阅读说明：本技术 抗蚀剂图案形成方法 (Resist pattern forming method ) 是由 河野绅一 白木雄哲 大野庆晃 齐藤彩 砂道智成 于 2018-12-20 设计创作，主要内容包括：本发明涉及一种抗蚀剂图案形成方法,具有：在支承体上使用抗蚀剂组合物形成膜厚7μm以上的抗蚀剂膜的工序、对所述抗蚀剂膜进行曝光的工序以及对曝光后的抗蚀剂膜进行显影而形成抗蚀剂图案的工序,作为所述抗蚀剂组合物,含有对显影液的溶解性因酸的作用而变化的基材成分、与由以通式(b1-1)表示的化合物构成的产酸剂,式(b1-1)中,R<Sup>b1</Sup>为芳基,R<Sup>b2</Sup>以及R<Sup>b3</Sup>为脂肪族烃基。R<Sup>b2</Sup>与R<Sup>b3</Sup>可以相互键合而形成环结构。L<Sup>b1</Sup>、L<Sup>b2</Sup>以及L<Sup>b3</Sup>为2价的连接基团或单键,X<Sup>-</Sup>是反荷阴离子。[化1]<Image he="163" wi="700" file="DDA0002553145320000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>(The present invention relates to a resist pattern forming method, comprising: a step of forming a resist film having a film thickness of 7 μm or more on a support using a resist composition, a step of exposing the resist film, and a step of developing the exposed resist film to form a resist pattern, wherein the resist composition comprises a base component having a solubility in a developer that changes by the action of an acid, and an acid generator comprising a compound represented by general formula (b1-1) wherein R is represented by formula (b1-1) b1 Is aryl, R b2 And R b3 Is an aliphatic hydrocarbon group. R b2 And R b3 May be bonded to each other to form a ring structure. L is b1 、L b2 And L b3 Is a 2-valent linking group or a single bond, X ‑ Is a counter anion. [ formula 1])

1. A resist pattern forming method includes the steps of: a step (i) for forming a resist film having a thickness of 7 μm or more on a support using the resist composition; a step (ii) of exposing the resist film; and (iii) developing the exposed resist film to form a resist pattern, the method for forming a resist pattern being characterized in that,

the resist composition contains a base component (A) whose solubility in a developer is changed by the action of an acid, and an acid generator (B1) composed of a compound represented by the following general formula (B1-1),

[ solution 1]

In the formula, R^b1Is an aryl group which may have a substituent, R^b2And R^b3Each independently is an aliphatic hydrocarbon group, R^b2And R^b3Can be bonded to each other to form a ring structure, L^b1、L^b2And L^b3Each independently being a 2-valent linking group or a single bond, X^-Is a counter anion.

2. The resist pattern forming method according to claim 1, wherein L in the formula (b1-1)^b1Is a single bond.

3. The resist pattern forming method according to claim 1 or 2, wherein X in the formula (b1-1)^-Is an anion represented by the following general formula (b1-1-an1), an anion represented by the general formula (b1-1-an2) or an anion represented by the general formula (b1-1-an3),

[ solution 2]

In the formula, R¹⁰¹And R¹⁰⁴～R¹⁰⁸Each independently represents a cyclic group which may have a substituent, a linear alkyl group which may have a substituent, or a linear alkenyl group which may have a substituent, R¹⁰⁴And R¹⁰⁵May be bonded to each other to form a ring structure, R¹⁰²Is a C1-5 fluoroalkyl group or a fluorine atom, Y¹⁰¹Is a 2-valent linking group or a single bond containing an oxygen atom, V¹⁰¹～V¹⁰³Each independently is a single bond, alkylene or fluoroalkylene group, L¹⁰¹～L¹⁰²Each independently being a single bond or an oxygen atom, L¹⁰³～L¹⁰⁵Each independently of the other being a single bond, -CO-or-SO₂-。

4. The method of forming a resist pattern according to any one of claims 1 to 3, wherein in the step (ii), the resist film is irradiated with KrF excimer laser light.

Technical Field

The present invention relates to a resist pattern forming method.

The present application claims priority based on japanese patent application No. 2017-254872 filed in japan on 12/28/2017, the contents of which are incorporated herein by reference.

Background

In the photolithography technique, for example, the following steps are performed: a resist film made of a resist material is formed on a substrate, and the resist film is selectively exposed to light and subjected to a development process, thereby forming a resist pattern having a predetermined shape on the resist film. A resist material in which an exposed portion of the resist film is changed to a property of dissolving in a developer is called a positive type, and a resist material in which an exposed portion of the resist film is changed to a property of not dissolving in a developer is called a negative type.

In recent years, in the manufacture of semiconductor devices and liquid crystal display devices, miniaturization of patterns has been advanced due to advances in photolithography technology. As a method for miniaturization, generally, the exposure light source is shortened in wavelength (increased in energy). Specifically, ultraviolet rays typified by g-rays and i-rays have been used, and KrF excimer lasers or ArF excimer lasers are currently used for mass production of semiconductor devices. Further, studies have been conducted on EUV (extreme ultraviolet), EB (electron beam), X-ray, and the like, which have a shorter wavelength (higher energy) than these excimer lasers.

The resist material is required to have lithographic characteristics such as sensitivity to these exposure light sources and resolution with which a pattern having a fine size can be reproduced.

As a resist material satisfying such a demand, a chemically amplified resist composition containing a base component whose solubility in a developer changes by the action of an acid and an acid generator component which generates an acid upon exposure has been conventionally used.

For example, when the developer is an alkaline developer (alkaline developing process), a composition containing a resin component (base resin) whose solubility in the alkaline developer is increased by the action of an acid and an acid generator component is generally used as a positive chemically amplified resist composition. When a resist film formed using the resist composition is selectively exposed to light during formation of a resist pattern, an acid is generated from an acid generator component in an exposed portion, the polarity of a matrix resin is increased by the action of the acid, and the exposed portion of the resist film becomes soluble in an alkaline developer. Therefore, by performing the alkali development, a positive pattern in which an unexposed portion of the resist film remains as a pattern is formed.

On the other hand, when such a chemically amplified resist composition is applied to a solvent development process using a developer containing an organic solvent (organic developer), the solubility in the organic developer is relatively lowered when the polarity of the base resin is increased, and thus the unexposed portions of the resist film are dissolved and removed by the organic developer to form a negative resist pattern in which the exposed portions of the resist film remain as a pattern. The solvent development process for forming the negative resist pattern in this way is also sometimes referred to as a negative development process.

Heretofore, as a matrix resin of a chemically amplified resist composition, for example, Polyhydroxystyrene (PHS) having high transparency to KrF excimer laser light (248nm) or a resin (PHS-based resin) in which a hydroxyl group thereof is protected by an acid-dissociable dissolution-inhibiting group has been used. Alternatively, for example, for ArF excimer laser light (193nm), a resin ((meth) acrylic resin) in which a hydroxyl group in a carboxyl group of (meth) acrylic acid is protected by an acid-dissociable, dissolution-inhibiting group is used (for example, see patent document 1).

As the acid dissociable dissolution inhibiting group, a so-called acetal group such as a chain ether group represented by 1-ethoxyethyl group or a cyclic ether group represented by tetrahydropyranyl group, a tertiary alkyl group represented by a tertiary butyl group, a tertiary alkoxycarbonyl group represented by a tertiary butoxycarbonyl group, or the like is mainly used.

Further, as an acid generator component used in a chemically amplified resist composition, various acid generator components have been proposed so far, and for example, an onium salt type acid generator such as an iodonium salt or a sulfonium salt, an oxime sulfonate type acid generator, a diazomethane type acid generator, a nitrobenzyl sulfonate type acid generator, an imino sulfonate type acid generator, a disulfone type acid generator, and the like are known.

Among these, onium salt type acid generators are generally used, and onium salt type acid generators having an onium ion such as triphenylsulfonium in the cation portion are mainly used. In the anion portion of the onium salt type acid generator, an alkyl sulfonic acid ion or a fluoro alkyl sulfonic acid ion in which a part or all of hydrogen atoms of an alkyl group thereof is substituted with a fluorine atom, or the like is generally used.

However, with the high integration of LSIs and the high speed of communications, the increase in memory capacity is required, and the further miniaturization of patterns is rapidly progressing. However, although lithography using electron beam or EUV aims to form a fine pattern of several tens of nanometers, it has many technical problems such as low productivity, and the technique for microfabrication has limitations.

In addition to miniaturization, development of a three-dimensional device has been advanced in which a memory is increased in capacity by stacking cells (cells).

Disclosure of Invention

Technical problem to be solved by the invention

The manufacturing of the three-dimensional structure device includes the following steps: a thick resist film having a film thickness of, for example, 7 μm or more, which is higher than that of the conventional one, is formed on the surface of a work, and a resist pattern is formed and etched. In the case of using the chemically amplified resist composition, it is more difficult to maintain the sensitivity at the time of exposure as the thickness of the resist film is thicker. When a thick resist film is formed using a conventional chemically amplified resist composition, the required exposure amount increases, which causes a problem of sensitivity decrease. Further, there is a problem that the resolution for development is lowered and it is difficult to obtain a desired resist pattern shape.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resist pattern forming method capable of forming a pattern having a good shape while exhibiting high sensitivity even when a thick resist film having a film thickness of 7 μm or more is formed.

Solution for solving the above technical problem

In order to solve the above-described problems, the present invention adopts the following configuration.

That is, a resist pattern forming method according to an aspect (aspect) of the present invention includes: a step (i) for forming a resist film having a thickness of 7 μm or more on a support using the resist composition; a step (ii) of exposing the resist film; and (iii) developing the exposed resist film to form a resist pattern, wherein the resist composition contains a base component (a) whose solubility in a developer changes by the action of an acid, and an acid generator (B1) comprising a compound represented by the following general formula (B1-1).

[ solution 1]

[ in the formula, R^b1Is an aryl group which may have a substituent. R^b2And R^b3Each independently is an aliphatic hydrocarbon group. R^b2And R^b3May be bonded to each other to form a ring structure. L is^b1、L^b2And L^b3Each independently is a 2-valent linking group or a single bond. X^-Is a counter anion.]

Effects of the invention

According to the present invention, it is possible to provide a resist pattern forming method capable of forming a pattern having a good shape while exhibiting high sensitivity even when a thick resist film having a film thickness of 7 μm or more is formed.

Detailed Description

In the present specification and the claims, "aliphatic" refers to a relative concept with respect to aromatic, and is defined to mean a group, a compound, or the like having no aromatic property.

Unless otherwise specified, "alkyl" includes straight-chain, branched-chain and cyclic 1-valent saturated hydrocarbon groups. The same applies to the alkyl group in the alkoxy group.

Unless otherwise specified, "alkylene" includes linear, branched and cyclic 2-valent saturated hydrocarbon groups.

The "haloalkyl group" is a group in which a part or all of hydrogen atoms of an alkyl group are substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

"fluoroalkyl" or "fluoroalkylene" refers to a group in which a part or all of the hydrogen atoms of an alkyl group or alkylene group are replaced with fluorine atoms.

The "structural unit" refers to a monomer unit (monomer unit) constituting a polymer compound (resin, polymer, copolymer).

The term "may have a substituent" includes the case where a hydrogen atom (-H) is substituted with a group having a valence of 1, and the case where a methylene group (-CH) is substituted₂-) two cases substituted with a 2-valent group.

"exposure" is a concept including irradiation of all radiation.

The "structural unit derived from an acrylate" refers to a structural unit formed by cleavage of an ethylenic double bond of an acrylate.

"acrylate" is acrylic acid (CH)₂CH-COOH) in the carboxyl terminal groupA compound obtained by substituting the hydrogen atom of (a) with an organic group.

The hydrogen atom bonded to the carbon atom at position α of the acrylate may be substituted with a substituent (R) which replaces the hydrogen atom bonded to the carbon atom at position α^α0) Examples of the atom or group other than hydrogen atom include alkyl groups having 1 to 5 carbon atoms and halogenated alkyl groups having 1 to 5 carbon atoms. In addition, the compound also comprises a substituent (R)^α0) Itaconate diester substituted with a substituent comprising an ester bond, substituent (R)^α0) α Hydroxyacrylate substituted with a hydroxyalkyl group or a group modifying the hydroxyl group, and the carbon atom at position α of the acrylate means a carbon atom to which the carbonyl group of acrylic acid is bonded, unless otherwise specified.

Hereinafter, an acrylate in which a hydrogen atom bonded to a carbon atom at the α -position is substituted with a substituent may be referred to as an α -substituted acrylate. Further, the acrylate and the α -substituted acrylate may be collectively referred to as "(α -substituted) acrylate". Further, acrylic acid in which a hydrogen atom bonded to a carbon atom at the α -position is substituted with a substituent is sometimes referred to as α -substituted acrylic acid. In addition, acrylic acid and α -substituted acrylic acid may be collectively referred to as "(α -substituted) acrylic acid".

The "structural unit derived from acrylamide" refers to a structural unit formed by cleavage of an ethylenic double bond of acrylamide.

The acrylamide may be substituted with a substituent for a hydrogen atom bonded to the carbon atom at the α -position, or one or both of the hydrogen atoms of the amino group of the acrylamide may be substituted with a substituent. Unless otherwise specified, the carbon atom at the α -position of acrylamide refers to a carbon atom to which the carbonyl group of acrylamide is bonded.

Examples of the substituent for replacing the hydrogen atom bonded to the carbon atom at the α -position of the acrylamide may include a group (substituent (R) exemplified as the substituent at the α -position in the α -substituted acrylate^α0) ) the same group.

The "structural unit derived from hydroxystyrene" means a structural unit in which an olefinic double bond of hydroxystyrene is cleaved. The "structural unit derived from a hydroxystyrene derivative" means a structural unit formed by cleavage of an olefinic double bond of the hydroxystyrene derivative.

The term "hydroxystyrene derivative" is intended to encompass compounds in which the hydrogen atom at the α -position of hydroxystyrene is substituted with another substituent such as an alkyl group or a haloalkyl group, and derivatives thereof. Examples of the derivatives thereof include compounds in which a hydrogen atom at the α -position is substituted with a substituent, and a hydrogen atom of a hydroxyl group of hydroxystyrene is substituted with an organic group; and a compound in which a substituent other than a hydroxyl group is bonded to a benzene ring of hydroxystyrene in which a hydrogen atom at the α -position may be substituted with a substituent. In addition, the α -position (carbon atom at α -position) means a carbon atom to which a benzene ring is bonded unless otherwise specified.

Examples of the substituent for substituting the hydrogen atom at the α -position of hydroxystyrene may include the same ones as those exemplified as the substituent at the α -position in the above-mentioned α -substituted acrylate.

The "structural unit derived from vinylbenzoic acid or a vinylbenzoic acid derivative" refers to a structural unit in which an ethylenic double bond of vinylbenzoic acid or a vinylbenzoic acid derivative is cleaved.

The term "vinylbenzoic acid derivative" is a concept including compounds in which the hydrogen atom at the α -position of vinylbenzoic acid is substituted with another substituent such as an alkyl group or a haloalkyl group, and derivatives thereof. Examples of the derivatives thereof include compounds in which a hydrogen atom at the α -position is substituted with a substituent, and a hydrogen atom of the carboxyl group of vinylbenzoic acid is substituted with an organic group; and a compound in which a substituent other than a hydroxyl group and a carboxyl group is bonded to a benzene ring of vinylbenzoic acid in which a hydrogen atom at the α -position may be substituted with a substituent. In addition, the α -position (carbon atom at α -position) means a carbon atom to which a benzene ring is bonded unless otherwise specified.

The alkyl group as the substituent at the α -position is preferably a linear or branched alkyl group, and specifically, an alkyl group having 1 to 5 carbon atoms (methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl) and the like are mentioned.

The "alkyl group as a substituent at the α -position" may specifically be a group obtained by substituting a part or all of hydrogen atoms of the "alkyl group as a substituent at the α -position" with a halogen atom. The halogen atom may, for example, be a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and a fluorine atom is particularly preferable.

The hydroxyalkyl group as the substituent at the α -position may specifically be one obtained by substituting a part or all of the hydrogen atoms of the above-mentioned "alkyl group as a substituent at the α -position" with a hydroxyl group. The number of hydroxyl groups in the hydroxyalkyl group is preferably 1 to 5, and most preferably 1.

In the present specification and the claims, depending on the structure represented by the chemical formula, there may be a structure of asymmetric carbon, and there may be a structure of enantiomer (enatiomer) or diastereomer (diasteromer), in which case these isomers are represented representatively by one chemical formula. These isomers may be used alone or as a mixture.

(resist Pattern Forming method)

The resist pattern forming method of the present embodiment includes: a step (i) for forming a resist film having a thickness of 7 μm or more on a support by using the resist composition; a step (ii) of exposing the resist film; and (iii) developing the exposed resist film to form a resist pattern. In the resist pattern forming method of the above-described embodiment, a specific resist composition is selected in the step (i).

The resist pattern forming method of this embodiment can be performed, for example, as follows.

Step (i):

first, a specific resist composition described later is applied to a support by a spin coater or the like, and is subjected to a baking (pre-bake) treatment at a temperature of, for example, 80 to 150 ℃, preferably 100 to 150 ℃ (more preferably more than 100 ℃ and not more than 150 ℃) for 40 to 120 seconds, preferably 60 to 120 seconds (more preferably 80 to 100 seconds), thereby forming a resist film having a thickness of 7 μm or more.

Step (ii):

next, the resist film is selectively exposed to light through a mask (mask pattern) having a predetermined pattern formed thereon using, for example, an exposure apparatus, and then baked (Post exposure bake, PEB) at a temperature of, for example, 80 to 150 ℃, preferably 90 to 130 ℃ for 40 to 120 seconds, preferably 60 to 100 seconds.

Step (iii):

next, the exposed resist film is subjected to a development treatment. The development treatment is performed using an alkaline developer in the case of an alkaline development process, and is performed using an organic solvent-containing developer (organic developer) in the case of a solvent development process.

After the development treatment, a rinsing treatment is preferably performed. The rinsing treatment is preferably a water rinsing using pure water in the case of an alkaline development process, and a rinsing liquid containing an organic solvent in the case of a solvent development process.

In the case of the solvent development process, after the development treatment or the rinsing treatment, a treatment of removing the developing solution or the rinsing solution attached to the pattern by the supercritical fluid may be performed.

Drying is performed after the development treatment or after the rinsing treatment. Further, a baking treatment (post-baking) may be performed after the above-described developing treatment according to circumstances.

As described above, a resist pattern can be formed.

The support is not particularly limited, and conventionally known supports may be used, and examples thereof include substrates for electronic components, and supports having a predetermined wiring pattern formed thereon. More specifically, the substrate may be a silicon wafer, a substrate made of metal such as copper, chromium, iron, or aluminum, or a glass substrate. As a material of the wiring pattern, for example, copper, aluminum, nickel, gold, or the like can be used.

The support may be one in which an inorganic and/or organic film is provided on the substrate as described above. As the inorganic film, an inorganic anti-reflection film (inorganic BARC) may be mentioned. Examples of the organic film include organic films such as an organic anti-reflection film (organic BARC) and an underlying organic film in a multilayer resist method.

Here, the multilayer resist method is a method in which at least one organic film (lower organic film) and at least one resist film (upper resist film) are provided on a substrate, and patterning of the lower organic film is performed using a resist pattern formed on the upper resist film as a mask, and it is considered that a pattern with a high aspect ratio can be formed. That is, according to the multilayer resist method, a desired thickness can be secured by the lower organic film, and therefore, the resist film can be thinned, and a fine pattern with a high aspect ratio can be formed.

Among the multilayer resist methods, there are basically classified into a method (2-layer resist method) using a two-layer structure of an upper resist film and a lower organic film; and a method (3-layer resist method) of a multilayer structure of three or more layers in which one or more intermediate layers (metal thin films and the like) are provided between an upper resist film and a lower organic film.

The resist pattern forming method of this aspect is a method useful for forming a resist film having a high film thickness, and the film thickness of the resist film formed in the step (i) is 7 μm or more.

The thickness of the resist film formed in the step (i) is more preferably 8 μm or more, particularly preferably 10 μm or more, and the upper limit of the thickness is substantially 30 μm or less.

The resist film formed using the specific resist composition described later has a transmittance (248nm) of preferably more than 2%, more preferably 2.1% or more, further preferably 5% or more, and particularly preferably 6% or more, when the film thickness is 15 μm, for example. The upper limit of the transmittance is substantially 20% or less.

The "transmittance of a resist film" as used herein means a value measured by forming a film of a resist composition as a sample on a plate-like quartz glass in a desired film thickness and transmitting light having a wavelength of 248nm by an ultraviolet-visible spectrophotometer.

The wavelength used for the exposure is not particularly limited, and ArF excimer laser, KrF excimer laser, F excimer laser, and the like can be used₂Excimer laser, EUV (extreme ultraviolet)) Radiation such as VUV (vacuum ultraviolet), EB (electron beam), X-ray, and soft X-ray.

The resist pattern forming method of this aspect is particularly preferable when KrF excimer laser light is irradiated to the resist film in the step (ii).

The resist film may be exposed to normal light in an inert gas such as air or nitrogen (dry exposure) or may be subjected to Liquid Immersion exposure (Liquid Immersion Lithography).

The immersion exposure is an exposure method in which a space between the resist film and the lens at the lowermost position of the exposure apparatus is filled with a solvent (immersion medium) having a refractive index larger than that of air in advance, and exposure is performed in this state (immersion exposure).

The liquid immersion medium is preferably a solvent having a refractive index higher than that of air and lower than that of the resist film to be exposed. The refractive index of the solvent is not particularly limited within the above range.

Examples of the solvent having a refractive index higher than that of air and lower than that of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.

Specific example of the fluorine-based inert liquid is C₃HCl₂F₅、C₄F₉OCH₃、C₄F₉OC₂H₅、C₅H₃F₇And liquids containing a fluorine-based compound as a main component, preferably a liquid having a boiling point of 70 to 180 ℃, and more preferably a liquid having a boiling point of 80 to 160 ℃. When the fluorine-based inert liquid has a boiling point in the above range, it is preferable because the medium used for the immersion liquid can be removed by a simple method after the exposure is completed.

As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are substituted by fluorine atoms is particularly preferable. The perfluoroalkyl compound may specifically be a perfluoroalkyl ether compound or a perfluoroalkyl amine compound.

More specifically, the perfluoroalkyl ether compound may, for example, be perfluoro (2-butyl-tetrahydrofuran) (boiling point: 102 ℃ C.), and the perfluoroalkyl amine compound may, for example, be perfluorotributylamine (boiling point: 174 ℃ C.).

As the immersion medium, water is preferably used from the viewpoints of cost, safety, environmental problems, versatility, and the like.

In the alkaline developing process, the alkaline developer used for the developing treatment may, for example, be a 0.1 to 10 mass% aqueous tetramethylammonium hydroxide (TMAH) solution.

The organic solvent contained in the organic developer used for the development treatment in the solvent development process may be selected from known organic solvents as long as it is an organic solvent capable of dissolving the component (a) (component (a) before exposure). Specifically, the solvent may include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, ether solvents and hydrocarbon solvents.

The ketone solvent is an organic solvent containing C — C (═ O) -C in the structure. The ester solvent is an organic solvent containing C — C (═ O) -O — C in the structure. The alcohol solvent is an organic solvent containing alcoholic hydroxyl groups in the structure. "alcoholic hydroxyl group" means a hydroxyl group bonded to a carbon atom of an aliphatic hydrocarbon group. Nitrile solvents are organic solvents that contain nitrile groups in the structure. The amide-based solvent is an organic solvent containing an amide group in the structure. The ether solvent is an organic solvent containing C-O-C in the structure.

In the case where the organic solvent includes a plurality of functional groups that impart characteristics to the respective solvents in its structure, the organic solvent may be classified into any solvent type including the functional groups. For example, diethylene glycol monomethyl ether also falls under the category of alcohol solvents or ether solvents.

The hydrocarbon solvent is a hydrocarbon solvent composed of a halogenated hydrocarbon and having no substituent other than a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.

Among the above, the organic solvent contained in the organic developer is preferably a polar solvent, and preferably a ketone solvent, an ester solvent, a nitrile solvent, or the like.

Examples of the ketone solvent include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methylethyl ketone, methylisobutyl ketone, acetylacetone, diacetone, ionone, diacetone alcohol, acetyl methanol, acetophenone, methylnaphthyl ketone, isophorone, propylene carbonate, γ -butyrolactone, and methyl amyl ketone (2-heptanone). Among these, methyl amyl ketone (2-heptanone) is preferred as the ketone solvent.

Examples of the ester solvent include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, methyl ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, ethylene glycol monoethyl ether acetate, ethyl glycolate, n-butyl, Propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetate, ethyl acetate, butyl acetate, n-, Methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propyl-3-methoxypropionate, and the like. Among these, butyl acetate is preferable as the ester solvent.

Examples of the nitrile solvent include acetonitrile, propionitrile, valeronitrile, and butyronitrile.

The organic developer may be blended with known additives as needed. Examples of the additive include surfactants. The surfactant is not particularly limited, and for example, an ionic or nonionic fluorine-based and/or silicon-based surfactant can be used. The surfactant is preferably a nonionic surfactant, more preferably a nonionic fluorine-based surfactant or a nonionic silicon-based surfactant.

When the surfactant is blended, the blending amount thereof is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and more preferably 0.01 to 0.5% by mass, based on the total amount of the organic developer.

The developing treatment may be carried out by a known developing method, and examples thereof include a method of immersing the support in a developer for a certain period of time (immersion method), a method of supporting the developer on the surface of the support by surface tension and standing for a certain period of time (stirring (paddle) method), a method of spraying the developer on the surface of the support (spray method), and a method of continuously discharging the developer onto the support rotating at a certain speed while scanning a developer discharge nozzle at a certain speed (dynamic dispensing method).

As the organic solvent contained in the rinse liquid used in the rinse treatment after the development treatment in the solvent development process, for example, an organic solvent that is difficult to dissolve the resist pattern among the organic solvents exemplified as the organic solvents used in the organic developer can be appropriately selected and used. At least 1 solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents is generally used. Among these, at least 1 kind selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, and amide solvents is preferable, at least 1 kind selected from alcohol solvents and ester solvents is more preferable, and alcohol solvents are particularly preferable.

The alcoholic solvent used in the rinse liquid is preferably a monohydric alcohol having 6 to 8 carbon atoms, and the monohydric alcohol may be linear, branched or cyclic. Specifically, it may, for example, be 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol or benzyl alcohol. Among these, 1-hexanol, 2-heptanol, and 2-hexanol are preferred, and 1-hexanol and 2-hexanol are more preferred.

These organic solvents may be used alone, or 2 or more kinds may be used in combination. Further, the solvent may be used in combination with an organic solvent or water other than those mentioned above. However, in consideration of the developing property, the amount of water to be added to the rinse liquid is preferably 30% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, and particularly preferably 3% by mass or less, based on the total amount of the rinse liquid.

The rinse liquid may be mixed with known additives as needed. Examples of the additive include surfactants. Examples of the surfactant include the same surfactants as described above, preferably nonionic surfactants, more preferably nonionic fluorine surfactants, or nonionic silicon surfactants.

When a surfactant is blended, the blending amount thereof is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and more preferably 0.01 to 0.5% by mass, based on the total amount of the rinsing liquid.

The rinsing treatment (cleaning treatment) using the rinsing liquid can be performed by a known rinsing method. Examples of the rinsing treatment include a method of continuously discharging a rinsing liquid onto a support rotating at a constant speed (spin coating method), a method of immersing the support in a rinsing liquid for a constant time (immersion method), and a method of spraying a rinsing liquid onto the surface of the support (spray method).

< resist composition >

In the resist pattern forming method of the present embodiment, a specific resist composition is used in the step (i).

The above-mentioned specific resist composition is a resist composition which generates an acid upon exposure and whose solubility in a developer is changed by the action of the acid. As an example of the resist composition, there is an embodiment containing a base component (a) (hereinafter, also referred to as "component a") whose solubility in a developer changes by the action of an acid, and an acid generator component (hereinafter, also referred to as "component B") which generates an acid upon exposure.

The resist composition of the present embodiment is suitable for resist pattern formation by exposure to KrF excimer laser light.

The resist composition of the present embodiment is useful as a resist for forming a resist film having a high thickness on a support, and is suitable for forming a resist film having a thickness of 7 μm or more.

When a resist film is formed using the resist composition of the present embodiment and the resist film is selectively exposed, an acid is generated in an exposed portion of the resist film, and the solubility of the component (a) in the developer changes due to the action of the acid, while the solubility of the component (a) in the developer does not change in an unexposed portion of the resist film, so that a difference in solubility in the developer occurs between the exposed portion and the unexposed portion of the resist film. Therefore, when the resist film is developed, in the case where the resist composition is a positive type, exposed portions of the resist film are dissolved and removed to form a positive type resist pattern, and in the case where the resist composition is a negative type, unexposed portions of the resist film are dissolved and removed to form a negative type resist pattern.

In this specification, a resist composition in which exposed portions of a resist film are dissolved and removed to form a positive resist pattern is referred to as a positive resist composition, and a resist composition in which unexposed portions of a resist film are dissolved and removed to form a negative resist pattern is referred to as a negative resist composition.

The resist composition of the present embodiment may be a positive resist composition or a negative resist composition.

The resist composition of the present embodiment can be used in an alkaline development process using an alkaline developer in a development process in forming a resist pattern, and can also be used in a solvent development process using a developer containing an organic solvent (organic developer) in the development process.

That is, the resist composition of the present embodiment is a "positive resist composition for an alkaline development process" in which a positive resist pattern is formed in an alkaline development process, and a "negative resist composition for a solvent development process" in which a negative resist pattern is formed in a solvent development process.

The resist composition of the present embodiment has an acid generating ability to generate an acid upon exposure, and the acid generator component (B) separately blended with the component (a) generates an acid upon exposure. In addition to the component (B), the component (A) may be a component which generates an acid upon exposure to light. When the component (a) is a base material component which generates an acid upon exposure and changes its solubility in a developer by the action of the acid, the component (a1) to be described later is preferably a polymer compound which generates an acid upon exposure and changes its solubility in a developer by the action of the acid. As such a polymer compound, a polymer compound having a structural unit that generates an acid by exposure can be used. Examples of the structural unit which generates an acid by exposure include known structural units.

(A) component

(A) The component is a base component whose solubility in the developer changes by the action of an acid.

The "base material component" in the present embodiment is an organic compound having film-forming ability, and an organic compound having a molecular weight of 500 or more is preferably used. When the molecular weight of the organic compound is 500 or more, film formation ability is improved, and a resist pattern of a nanometer order is easily formed.

Organic compounds used as a component of the substrate are broadly classified into non-polymers and polymers.

As the non-polymer, a non-polymer having a molecular weight of 500 or more and less than 4000 is generally used. Hereinafter, in the case where "low molecular compound" is mentioned, it means a non-polymer having a molecular weight of 500 or more and less than 4000.

As the polymer, a polymer having a molecular weight of 1000 or more is generally used. Hereinafter, when "resin", "high molecular compound" or "polymer" is referred to, it means a polymer having a molecular weight of 1000 or more.

As the molecular weight of the polymer, a weight average molecular weight in terms of polystyrene based on GPC (gel permeation chromatography) was used.

In the case where the resist composition of the present embodiment is a "negative resist composition for an alkaline development process" in which a negative resist pattern is formed in an alkaline development process, or a "positive resist composition for a solvent development process" in which a positive resist pattern is formed in a solvent development process, it is preferable to use a base material component (a-2) (hereinafter referred to as "a-2 component") soluble in an alkaline developer, and further blend a crosslinking agent component as the (a) component. When an acid is generated from the component (B) by exposure, for example, the acid acts to crosslink the component (a-2) with the crosslinking agent component, and as a result, the solubility in an alkaline developer decreases (the solubility in an organic developer increases).

Therefore, in the formation of a resist pattern, when a resist film obtained by applying the resist composition to a support is selectively exposed, the exposed portion of the resist film is rendered insoluble to an alkaline developer (rendered soluble to an organic developer), while the unexposed portion of the resist film remains soluble to an alkaline developer (rendered insoluble to an organic developer), and therefore, development with an alkaline developer enables the formation of a negative resist pattern. In addition, at this time, a positive resist pattern can be formed by development with an organic developer.

As the component (a-2), a resin soluble in an alkaline developer (hereinafter referred to as "alkali-soluble resin") can be used.

Examples of the alkali-soluble resin include: a resin having a structural unit derived from at least one member selected from the group consisting of α - (hydroxyalkyl) acrylic acid and alkyl esters of α - (hydroxyalkyl) acrylic acid (preferably alkyl esters having 1 to 5 carbon atoms), disclosed in Japanese unexamined patent publication No. 2000-206694; acrylic resin or polycycloolefin resin having a sulfonamide group in which a hydrogen atom bonded to a carbon atom at the α -position may be substituted with a substituent, as disclosed in U.S. Pat. No. 6949325; acrylic resins containing a fluorinated alcohol in which a hydrogen atom bonded to a carbon atom at the α -position may be substituted with a substituent, as disclosed in U.S. Pat. No. 6949325, JP 2005-336452 and JP 2006-317803; the alkali-soluble resins disclosed in Japanese patent application laid-open No. 2006-259582, such as the polycycloolefin resins having a fluorinated alcohol, are preferable because they can form a good resist pattern with less swelling.

The α - (hydroxyalkyl) acrylic acid represents one or both of acrylic acid in which a hydrogen atom bonded to the α -position carbon atom is optionally substituted with a substituent, acrylic acid in which a hydrogen atom is bonded to the α -position carbon atom to which a carboxyl group is bonded, and α -hydroxyalkyl acrylic acid in which a hydroxyalkyl group (preferably a hydroxyalkyl group having 1 to 5 carbon atoms) is bonded to the α -position carbon atom.

As the crosslinking agent component, for example, an amino crosslinking agent such as glycoluril having a methylol group or an alkoxymethyl group, a melamine crosslinking agent, or the like is preferably used because a good resist pattern having a small swelling is easily formed. The amount of the crosslinking agent component to be blended is preferably 1 to 50 parts by mass per 100 parts by mass of the alkali-soluble resin.

In the case where the resist composition of the present embodiment is a "positive resist composition for an alkaline development process" in which a positive resist pattern is formed in an alkaline development process or a "negative resist composition for a solvent development process" in which a negative resist pattern is formed in a solvent development process, it is preferable to use, as the component (a), a base component (a-1) (hereinafter referred to as "component (a-1)") whose polarity is increased by the action of an acid. By using the (A-1) component, since the polarity of the base material component changes before and after exposure, a good development contrast can be obtained not only in the alkali development process but also in the solvent development process.

In the resist composition of the present embodiment, the component (a) is preferably the component (a-1). That is, the resist composition of the present embodiment is preferably a "positive resist composition for an alkaline development process" in which a positive resist pattern is formed in an alkaline development process, or a "negative resist composition for a solvent development process" in which a negative resist pattern is formed in a solvent development process.

A high molecular weight compound and/or a low molecular weight compound can be used as the component (a).

When the component (A) is the component (A-1), the component (A-1) is preferably a compound containing a resin component (A1) (hereinafter, also referred to as the "component (A1)") whose solubility in a developer is changed by the action of an acid. In this case, at least the component (a1) may be used as the component (a), and other high molecular compounds and/or low molecular compounds may be used together with the component (a 1).

With respect to the (A1) component

(A1) The component is a resin component whose solubility in the developer changes by the action of an acid, and is preferably a resin component containing the following polymer compound: a polymer compound having a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid.

The component (a1) preferably has a structural unit (a10) containing a hydroxystyrene skeleton in addition to the structural unit (a 1). The component (A1) may have other structural units as required in addition to the structural unit (a1) or in addition to the structural unit (a1) and the structural unit (a 10).

By using the (a1) component having the structural unit (a1), the polarity of the resin component changes before and after exposure, and a good development contrast can be obtained not only in the alkali development process but also in the solvent development process between the exposed portion and the unexposed portion of the resist film.

When an alkaline developing process is applied, the component (a1) is hardly soluble in an alkaline developer before exposure, and when an acid is generated from the component (B) by exposure, the polarity thereof increases by the action of the acid, and the solubility in the alkaline developer increases. Therefore, in the formation of a resist pattern, when a resist film obtained by applying the resist composition to a support is selectively exposed, the solubility of the exposed portion of the resist film in an alkaline developer is changed from sparingly soluble to soluble, while the unexposed portion of the resist film remains sparingly soluble and unchanged, so that a positive resist pattern can be formed by alkaline development.

On the other hand, in the case of applying the solvent development process, the solubility of the component (a1) in the organic developer before exposure is high, and when acid is generated from the component (B) by exposure, the polarity thereof increases by the action of the acid, and the solubility in the organic developer decreases. Therefore, in the formation of a resist pattern, when a resist film obtained by applying the resist composition to a support is selectively exposed, the solubility of the exposed portion of the resist film in an organic developer is changed from soluble to poorly soluble, while the unexposed portion of the resist film remains soluble and does not change, so that a negative resist pattern can be formed by development with an organic developer.

With respect to structural unit (a 1):

the structural unit (a1) is a structural unit containing an acid-decomposable group whose polarity is increased by the action of an acid.

The "acid-decomposable group" is an acid-decomposable group having a structure in which at least a part of the bonds in the structure of the acid-decomposable group can be cleaved by the action of an acid.

Examples of the acid-decomposable group whose polarity is increased by the action of an acid include groups which are decomposed by the action of an acid to generate a polar group.

Examples of the polar group include a carboxyl group, a hydroxyl group, an amino group and a sulfonic acid group (-SO)₃H) And the like. Among these, a polar group containing-OH in the structure (hereinafter also referred to as "OH-containing polar group") is preferable, a carboxyl group or a hydroxyl group is more preferable, and a carboxyl group is particularly preferable.

More specifically, the acid-decomposable group may, for example, be a group in which the above-mentioned polar group is protected with an acid-dissociable group (for example, a group in which a hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).

The "acid-dissociable group" herein means both of the following: (i) an acid-dissociable group having a bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group that can be cleaved by the action of an acid; or (ii) a group in which a part of the bond is cleaved by the action of an acid and then decarboxylation is further caused, whereby the bond between the acid-dissociable group and the atom adjacent to the acid-dissociable group can be cleaved.

The acid-dissociable group constituting the acid-dissociable group must be a group having a polarity lower than that of the polar group generated by dissociation of the acid-dissociable group, and thus when the acid-dissociable group dissociates by the action of an acid, a polar group having a polarity higher than that of the acid-dissociable group is generated and the polarity increases. As a result, the polarity of the entire component (a1) increases. The solubility in the developer is relatively changed by the increase in polarity, and the solubility is increased when the developer is an alkaline developer and is decreased when the developer is an organic developer.

Examples of the acid-dissociable group include those proposed as acid-dissociable groups of matrix resins for chemically amplified resist compositions.

Examples of the group proposed as the acid-dissociable group of the base resin for the chemically amplified resist composition include, specifically, "acetal type acid-dissociable group", "tertiary alkyl ester type acid-dissociable group" and "tertiary alkoxycarbonyl acid-dissociable group" described below.

Acetal type acid-dissociable group:

examples of the acid-dissociable group that protects the carboxyl group or the hydroxyl group of the polar group include acid-dissociable groups represented by the following general formula (a1-r-1) (hereinafter also referred to as "acetal-type acid-dissociable groups").

[ solution 2]

[ wherein, Ra'¹、Ra’²Is a hydrogen atom or an alkyl group, Ra'³Is hydrocarbyl, Ra'³May be substituted with Ra'¹、Ra’²Any of which is bonded to form a ring.]

In the formula (a1-r-1), Ra 'is preferred'¹And Ra'²At least one of them is a hydrogen atom, and more preferably both are hydrogen atoms.

In Ra'¹Or Ra'²In the case of an alkyl group, the alkyl group may be the same as the alkyl group exemplified as the substituent which may be bonded to the carbon atom at position α in the description of the α -substituted acrylate, and preferably an alkyl group having 1 to 5 carbon atoms.

In the formula (a1-r-1), as Ra'³Examples of the hydrocarbon group of (3) include a linear or branched alkyl group and a cyclic hydrocarbon group.

The number of carbon atoms of the linear alkyl group is preferably 1 to 5, more preferably 1 to 4, and further preferably 1 or 2. Specifically, the alkyl group may include methyl, ethyl, n-propyl, n-butyl, n-pentyl and the like. Among them, methyl, ethyl or n-butyl is preferable, and methyl or ethyl is more preferable.

The branched alkyl group preferably has 3 to 10 carbon atoms, more preferably 3 to 5 carbon atoms. Specifically, the alkyl group may include isopropyl, isobutyl, tert-butyl, isopentyl, neopentyl, 1-diethylpropyl, and 2, 2-dimethylbutyl, with isopropyl being preferred.

In Ra'³When the hydrocarbon group is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a polycyclic group, or a monocyclic group.

The alicyclic hydrocarbon group as a monocyclic group is preferably a group obtained by removing 1 hydrogen atom from a monocyclic hydrocarbon. The monocycloalkane is preferably a monocycloalkane having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane.

The aliphatic hydrocarbon group of the polycyclic group is preferably a group obtained by removing 1 hydrogen atom from a polycycloalkane, and the polycycloalkane is preferably a C7-12 polycycloalkane, and specifically, adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like can be mentioned.

In Ra'³When the cyclic hydrocarbon group of (2) is an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least 1 aromatic ring.

The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n +2 pi electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and particularly preferably 6 to 12.

Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, phenanthrene, and the like; and an aromatic heterocyclic ring in which a part of carbon atoms constituting the aromatic hydrocarbon ring is substituted with a hetero atom. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.

As Ra'³The aromatic hydrocarbon group in (1) may specifically be a group (aryl or heteroaryl) obtained by removing 1 hydrogen atom from the aromatic hydrocarbon ring or aromatic heterocyclic ring; a group obtained by removing 1 hydrogen atom from an aromatic compound (for example, biphenyl, fluorene, or the like) having 2 or more aromatic rings; and those in which 1 hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocyclic ring is substituted with an alkylene group (for example, arylalkyl groups such as benzyl, phenethyl, 1-naphthylmethyl, 2-naphthylmethyl, 1-naphthylethyl and 2-naphthylethyl). The number of carbon atoms of the alkylene group bonded to the aromatic hydrocarbon ring or the aromatic heterocyclic ring is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

In Ra'³And Ra'¹、Ra’²Any one of which is bonded to form a ringIn the case of (3), the cyclic group is preferably a four-to seven-membered ring, more preferably a four-to six-membered ring. Specific examples of the cyclic group include tetrahydropyranyl group and tetrahydrofuranyl group.

Tertiary alkyl ester type acid-dissociable group:

examples of the acid-dissociable group that protects the carboxyl group of the polar group include acid-dissociable groups represented by the following general formula (a 1-r-2).

For convenience of explanation, a group composed of an alkyl group in the acid-dissociable group represented by the following formula (a1-r-2) will be referred to as a "tertiary alkyl ester-type acid-dissociable group" hereinafter.

[ solution 3]

[ wherein, Ra'⁴～Ra’⁶Are each hydrocarbyl, Ra'⁵、Ra’⁶May be bonded to each other to form a ring.]

As Ra'⁴～Ra’⁶The hydrocarbyl group of (A) may, for example, be represented by the formula Ra'³The same hydrocarbon group.

Ra’⁴Preferably an alkyl group having 1 to 5 carbon atoms. In Ra'⁵And Ra'⁶Examples of the "ring" formed by bonding to each other include those represented by the following general formulae (a1-r 2-1). On the other hand, in Ra'⁴～Ra’⁶Examples of the hydrocarbon group which may be independent of each other include groups represented by the following general formulae (a1-r 2-2).

[ solution 4]

[ wherein, Ra'¹⁰Represents an alkyl group having 1 to 10 carbon atoms, Ra'¹¹Is represented by and Ra'¹⁰The bonded carbon atoms together form a radical of an aliphatic cyclic group, Ra'¹²～Ra’¹⁴Each independently represents a hydrocarbon group.]

Ra 'of the formula (a1-r 2-1)'¹⁰The alkyl group having 1 to 10 carbon atoms in (a1-r-1) is preferably Ra'³Examples of the "alkyl" may include linear and branched alkyl.

Ra 'of the formula (a1-r 2-1)'¹¹And Ra'¹⁰The alicyclic ring group formed together with the bonded carbon atoms is preferably Ra 'in the formula (a 1-r-1)'³The monocyclic group or polycyclic group is preferably the monocyclic group or the polycyclic group, and more preferably the monocyclic group is the monocyclic group.

In the formula (a1-r2-2), Ra'¹²And Ra'¹⁴Each independently preferably an alkyl group having 1 to 10 carbon atoms, and the alkyl group is more preferably Ra 'in the formula (a 1-r-1)'³The group exemplified as the linear or branched alkyl group of (2) is more preferably a linear alkyl group having 1 to 5 carbon atoms, and particularly preferably a methyl group or an ethyl group.

In the formula (a1-r2-2), Ra'¹³Preferably Ra 'in the formula (a 1-r-1)'³Examples of the hydrocarbon group of (3) include a linear or branched alkyl group and an aliphatic hydrocarbon group which is a monocyclic group or polycyclic group. Of these, Ra 'is more preferable'³The monocyclic group or polycyclic group of the above-mentioned aliphatic hydrocarbon group.

Specific examples of the group represented by the above formula (a1-r2-1) are shown below. Indicates a bond (the same as in the present specification hereinafter).

[ solution 5]

[ solution 6]

Specific examples of the group represented by the above formula (a1-r2-2) are shown below.

[ solution 7]

Tertiary alkoxycarbonyl acid-dissociable group:

examples of the acid-dissociable group that protects the hydroxyl group of the polar group include acid-dissociable groups represented by the following general formula (a1-r-3) (hereinafter, for convenience of explanation, also referred to as "tertiary alkoxycarbonyl acid-dissociable groups").

[ solution 8]

[ wherein, Ra'⁷～Ra’⁹Are each an alkyl group.]

In the formula (a1-r-3), Ra'⁷～Ra’⁹The alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms.

In addition, the total carbon number of each alkyl group is preferably 3 to 7, more preferably 3 to 5, and most preferably 3 to 4.

Among the above, the acid-decomposable group in the structural unit (a1) preferably contains an acid-dissociable group represented by the above general formula (a1-r-2), more preferably a group represented by the above general formula (a1-r2-1) or a group represented by the above general formula (a1-r2-2), because the acid-decomposability is higher due to the action of an acid.

Examples of the structural unit (a1) include a structural unit derived from an acrylate ester in which a hydrogen atom bonded to the carbon atom at the α -position is substituted with a substituent, a structural unit derived from acrylamide, a structural unit derived from hydroxystyrene or a hydroxystyrene derivative in which at least a part of the hydrogen atoms in the hydroxyl groups are protected with an acid-dissociable group, and a structural unit derived from vinylbenzoic acid or a vinylbenzoic acid derivative in which at least a part of the hydrogen atoms in-C (═ O) -OH is protected with an acid-dissociable group.

As the structural unit (a1), among the above structural units, a structural unit derived from an acrylate in which a hydrogen atom bonded to a carbon atom at the α -position may be substituted with a substituent is preferable.

As a preferred specific example of the above-mentioned structural unit (a1), a structural unit represented by the following general formula (a1-1) or general formula (a1-2) may be mentioned.

[ solution 9]

[ wherein R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms. Va (Va)¹Is a 2-valent hydrocarbon group which may have an ether bond, n_a1Is 0 to 2, Ra¹Is an acid-dissociable group represented by the above formula (a1-r-1) or (a 1-r-2). Wa¹Is n_a2A hydrocarbon radical having a valence of +1, n_a2Is 1 to 3, Ra²Is an acid-dissociable group represented by the formula (a1-r-1) or (a 1-r-3).]

In the above formula (a1-1), the alkyl group having 1 to 5 carbon atoms in R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specifically, it may, for example, be a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group or a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which a part or all of hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. The halogen atom may, for example, be a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and a fluorine atom is particularly preferable.

R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluoroalkyl group having 1 to 5 carbon atoms, and most preferably a hydrogen atom or a methyl group from the viewpoint of easy industrial availability.

In the formula (a1-1), Va¹The 2-valent hydrocarbon group in (b) may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

As Va¹The aliphatic hydrocarbon group of the 2-valent hydrocarbon group in (b) may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, and a saturated aliphatic hydrocarbon group is generally preferred.

More specifically, the aliphatic hydrocarbon group may, for example, be a straight-chain or branched aliphatic hydrocarbon group or an aliphatic hydrocarbon group having a ring in its structure.

The number of carbon atoms of the linear or branched aliphatic hydrocarbon group is preferably 1 to 10, more preferably 1 to 6, still more preferably 1 to 4, and most preferably 1 to 3.

The linear aliphatic hydrocarbon group is preferably a linear alkylene group, and specifically, it may, for example, be methylene [ -CH ]₂-]Ethylene [ - (CH)₂)₂-]Propylene [ - (CH)₂)₃-]Butylene [ - (CH)₂)₄-]- (CH) pentylene [ - (CH)₂)₅-]And the like.

The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specifically may, for example, be-CH (CH)₃)-、-CH(CH₂CH₃)-、-C(CH₃)₂-、-C(CH₃)(CH₂CH₃)-、-C(CH₃)(CH₂CH₂CH₃)-、-C(CH₂CH₃)₂-isoalkylmethylene; -CH (CH)₃)CH₂-、-CH(CH₃)CH(CH₃)-、-C(CH₃)₂CH₂-、-CH(CH₂CH₃)CH₂-、-C(CH₂CH₃)₂-CH₂-isoalkylethylene; -CH (CH)₃)CH₂CH₂-、-CH₂CH(CH₃)CH₂-isoalkylpropylene; -CH (CH)₃)CH₂CH₂CH₂-、-CH₂CH(CH₃)CH₂CH₂An alkylalkylene group such as an alkylbutylene group, etc. The alkyl group in the alkyl alkylene group is preferably a straight-chain alkyl group having 1 to 5 carbon atoms.

Examples of the aliphatic hydrocarbon group having a ring in the above structure include an alicyclic hydrocarbon group (a group obtained by removing 2 hydrogen atoms from an aliphatic hydrocarbon ring), a group in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and a group in which an alicyclic hydrocarbon group is interposed between linear or branched aliphatic hydrocarbon groups. The linear or branched aliphatic hydrocarbon group may, for example, be the same as the linear aliphatic hydrocarbon group or the branched aliphatic hydrocarbon group.

The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.

The alicyclic hydrocarbon group may be polycyclic or monocyclic. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing 2 hydrogen atoms from a monocycloparaffin. The monocycloparaffins are preferably those having 3 to 6 carbon atoms, and specifically, cyclopentane, cyclohexane and the like are exemplified. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing 2 hydrogen atoms from a polycycloalkane, and the polycycloalkane is preferably a C7-12 polycycloalkane, and specifically includes adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like.

As Va¹The aromatic hydrocarbon group of the 2-valent hydrocarbon group in (1) is a hydrocarbon group having an aromatic ring.

The number of carbon atoms of the aromatic hydrocarbon group is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 10. Wherein the number of carbons does not include the number of carbons in the substituent.

Specific examples of the aromatic ring included in the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, phenanthrene, and the like; and an aromatic heterocyclic ring in which a part of carbon atoms constituting the aromatic hydrocarbon ring is substituted with a hetero atom. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom.

Specific examples of the aromatic hydrocarbon group include a group (arylene group) obtained by removing 2 hydrogen atoms from the aromatic hydrocarbon ring; a group (aryl group) obtained by removing 1 hydrogen atom from the aromatic hydrocarbon ring, wherein 1 hydrogen atom is substituted with an alkylene group (for example, a group obtained by removing 1 hydrogen atom from an aryl group in an arylalkyl group such as benzyl, phenethyl, 1-naphthylmethyl, 2-naphthylmethyl, 1-naphthylethyl, 2-naphthylethyl) and the like. The number of carbon atoms of the alkylene group (alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

In the formula (a1-2), Wa¹N in (1)_a2The +1 valent hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. TheThe aliphatic hydrocarbon group means a hydrocarbon group having no aromatic character, and may be saturated or unsaturated, and is preferably saturated in general. Examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group having a ring in the structure, and a combination of a linear or branched aliphatic hydrocarbon group and an aliphatic hydrocarbon group having a ring in the structure.

N is_a2The +1 valence is preferably 2 to 4 valence, more preferably 2 or 3 valence.

Specific examples of the structural unit represented by the above formula (a1-1) are shown below. In the following formulae, R^αRepresents a hydrogen atom, a methyl group or a trifluoromethyl group.

[ solution 10]

[ solution 11]

[ solution 12]

[ solution 13]

[ solution 14]

Specific examples of the structural unit represented by the above formula (a1-2) are shown below.

[ solution 15]

AsAmong the structural units (a1), the structural unit represented by the above general formula (a1-1) is more preferable, and among them, the structural unit represented by the general formula (a1-1) and Ra are particularly preferable¹Is a structural unit of an acid-dissociable group represented by the formula (a 1-r-2).

(A1) The constituent unit (a1) of component (a) may be 1 or 2 or more.

(A1) The proportion of the structural unit (a1) in the component (a1) is preferably 5 to 30 mol%, more preferably 7 to 30 mol%, and still more preferably 10 to 25 mol% based on the total structural units (100 mol%) constituting the component (a 1).

By setting the ratio of the structural unit (a1) to be equal to or higher than the lower limit of the above-described preferable range, a resist pattern can be easily obtained, the resolution is further improved, and a pattern having a good shape can be easily formed. Further, by setting the above ratio to an upper limit or lower, balance with other constituent units can be achieved.

With respect to structural unit (a 10):

the structural unit (a10) is a structural unit containing a hydroxystyrene skeleton.

As the above-mentioned structural unit (a10), for example, a structural unit represented by the following general formula (a10-1) is preferable.

[ solution 16]

[ wherein R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms. Ya^x1Is a single bond or a 2-valent linking group. Wa^x1Is (n)_ax1+1) a valent aromatic hydrocarbon radical. n is_ax1Is an integer of 1 to 3.]

In the formula (a10-1), R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.

The alkyl group having 1 to 5 carbon atoms in R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specifically, it may, for example, be a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group or a neopentyl group. The haloalkyl group having 1 to 5 carbon atoms as R is a group in which a part or all of hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. The halogen atom may, for example, be a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and a fluorine atom is particularly preferable.

R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluoroalkyl group having 1 to 5 carbon atoms, and most preferably a hydrogen atom or a methyl group from the viewpoint of easy industrial availability.

In said formula (a10-1), Ya^x1Is a single bond or a 2-valent linking group.

As Ya^x1The 2-valent linking group in (2) may, for example, be a 2-valent hydrocarbon group which may have a substituent, or a 2-valent linking group containing a hetero atom, as a preferable group.

A 2-valent hydrocarbon group which may have a substituent:

at Ya^x1When the hydrocarbon group is a 2-valent hydrocarbon group which may have a substituent, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

··Ya^x1Aliphatic hydrocarbon group of (1)

The aliphatic hydrocarbon group represents a hydrocarbon group having no aromatic character. The aliphatic hydrocarbon group may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, and is preferably a saturated aliphatic hydrocarbon group.

Examples of the aliphatic hydrocarbon group include a straight-chain or branched-chain aliphatic hydrocarbon group, and an aliphatic hydrocarbon group having a ring in the structure.

Linear or branched aliphatic hydrocarbon radical

The number of carbon atoms of the straight-chain aliphatic hydrocarbon group is preferably 1 to 10, more preferably 1 to 6, still more preferably 1 to 4, and most preferably 1 to 3.

The linear aliphatic hydrocarbon group is preferably a linear alkylene group, and specifically, it may, for example, be methylene [ -CH ]₂-]Ethylene [ - (CH)₂)₂-]Propylene [ - (CH)₂)₃-]Butylene [ - (CH)₂)₄-]- (CH) pentylene [ - (CH)₂)₅-]And the like.

The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, still more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms.

The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specifically may, for example, be-CH (CH)₃)-、-CH(CH₂CH₃)-、-C(CH₃)₂-、-C(CH₃)(CH₂CH₃)-、-C(CH₃)(CH₂CH₂CH₃)-、-C(CH₂CH₃)₂-isoalkylmethylene; -CH (CH)₃)CH₂-、-CH(CH₃)CH(CH₃)-、-C(CH₃)₂CH₂-、-CH(CH₂CH₃)CH₂-、-C(CH₂CH₃)₂-CH₂-isoalkylethylene; -CH (CH)₃)CH₂CH₂-、-CH₂CH(CH₃)CH₂-isoalkylpropylene; -CH (CH)₃)CH₂CH₂CH₂-、-CH₂CH(CH₃)CH₂CH₂An alkylalkylene group such as an alkylbutylene group, etc. The alkyl group in the alkyl alkylene group is preferably a straight-chain alkyl group having 1 to 5 carbon atoms.

The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluoroalkyl group having 1 to 5 carbon atoms and substituted with a fluorine atom, and a carbonyl group.

Aliphatic hydrocarbon groups containing rings in the structure

Examples of the cyclic aliphatic hydrocarbon group having a ring in the structure include a cyclic aliphatic hydrocarbon group (a group obtained by removing 2 hydrogen atoms from an aliphatic hydrocarbon ring) which may have a substituent and which has a hetero atom in the ring structure, a group in which the cyclic aliphatic hydrocarbon group is bonded to an end of a linear or branched aliphatic hydrocarbon group, and a group in which the cyclic aliphatic hydrocarbon group is interposed between linear or branched aliphatic hydrocarbon groups. Examples of the linear or branched aliphatic hydrocarbon group may include the same aliphatic hydrocarbon groups as described above.

The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms.

The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing 2 hydrogen atoms from a monocycloparaffin. The monocycloalkane is preferably a monocycloalkane having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing 2 hydrogen atoms from a polycycloalkane, and the polycycloalkane is preferably a C7-12 polycycloalkane, and specifically includes adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like.

The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, and a carbonyl group.

The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.

The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and a tert-butoxy group, and most preferably a methoxy group or an ethoxy group.

Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.

Examples of the "haloalkyl" group as the substituent may include a group in which a part or all of hydrogen atoms of the alkyl group are substituted with the halogen atom.

The cyclic aliphatic hydrocarbon group may be partially substituted with a substituent containing a hetero atom, the carbon atom constituting the ring structure of the cyclic aliphatic hydrocarbon group. The substituent containing a hetero atom is preferably — O-, -C (═ O) -O-, -S (═ O)₂-、-S(＝O)₂-O-。

··Ya^x1Aromatic hydrocarbon radical in (1)

The aromatic hydrocarbon group is a hydrocarbon group having at least 1 aromatic ring.

The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n +2 pi electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and particularly preferably 6 to 12. Wherein the number of carbons does not include the number of carbons in the substituent. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, phenanthrene, and the like; and an aromatic heterocyclic ring in which a part of carbon atoms constituting the aromatic hydrocarbon ring is substituted with a hetero atom. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom.

Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.

Specific examples of the aromatic hydrocarbon group include a group (arylene group or heteroarylene group) obtained by removing 2 hydrogen atoms from the aromatic hydrocarbon ring or aromatic heterocyclic ring; a group obtained by removing 2 hydrogen atoms from an aromatic compound (for example, biphenyl, fluorene, or the like) having 2 or more aromatic rings; and a group (aryl or heteroaryl) obtained by removing 1 hydrogen atom from the aromatic hydrocarbon ring or aromatic heterocyclic ring, wherein 1 hydrogen atom is substituted with an alkylene group (for example, a group obtained by removing 1 hydrogen atom from an aryl group in an arylalkyl group such as benzyl, phenethyl, 1-naphthylmethyl, 2-naphthylmethyl, 1-naphthylethyl, 2-naphthylethyl, etc.), and the like. The alkylene group bonded to the aryl or heteroaryl group preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

In the aromatic hydrocarbon group, a hydrogen atom of the aromatic hydrocarbon group may be substituted with a substituent. For example, a hydrogen atom bonded to an aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a haloalkyl group, and a hydroxyl group.

The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.

Examples of the "alkoxy" and "halogen" and "haloalkyl" as the substituent include those exemplified as substituents for substituting a hydrogen atom of the cyclic aliphatic hydrocarbon group.

Heteroatom-containing 2-valent linking groups:

at Ya^x1In the case of a heteroatom-containing 2-valent linking group, examples of the linking group include-O-, -C (═ O) -, -O-C (═ O) -O-, -C (═ O) -NH-, -NH-C (═ NH) - (H may be substituted with a substituent such as an alkyl group or an acyl group), -S-, -S (═ O)₂-、-S(＝O)₂-O-, of the formula-Y²¹-O-Y²²-、-Y²¹-O-、-Y²¹-C(＝O)-O-、-C(＝O)-O-Y²¹-、-[Y²¹-C(＝O)-O]_m”-Y²²-、-Y²¹-O-C(＝O)-Y²²-or-Y²¹-S(＝O)₂-O-Y²²A group represented by (wherein Y is)²¹And Y²²Each independently represents a 2-valent hydrocarbon group which may have a substituent, O represents an oxygen atom, and m' represents an integer of 0 to 3.]Etc. as preferred groups.

In the case where the heteroatom-containing 2-valent linking group is — C (═ O) -NH-, -C (═ O) -NH-C (═ O) -, -NH-C (═ NH) -, H thereof may be substituted with a substituent such as an alkyl group or an acyl group. The number of carbon atoms of the substituent (such as alkyl group or acyl group) is preferably 1 to 10, more preferably 1 to 8, and particularly preferably 1 to 5.

General formula-Y²¹-O-Y²²-、-Y²¹-O-、-Y²¹-C(＝O)-O-、-C(＝O)-O-Y²¹-、-[Y²¹-C(＝O)-O]_m”-Y²²-、-Y²¹-O-C(＝O)-Y²²-or-Y²¹-S(＝O)₂-O-Y²²In (Y)²¹And Y²²Each independently is a 2-valent hydrocarbon group which may have a substituent. Examples of the 2-valent hydrocarbon group may include the same groups as those (the 2-valent hydrocarbon group which may have a substituent) exemplified in the description of the 2-valent linking group.

As Y²¹The aliphatic hydrocarbon group is preferably a linear aliphatic hydrocarbon group, more preferably a linear alkylene group, still more preferably a linear alkylene group having 1 to 5 carbon atoms,particular preference is given to methylene or ethylene.

As Y²²The aliphatic hydrocarbon group is preferably a linear or branched aliphatic hydrocarbon group, and more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.

Is represented by the formula- [ Y ]²¹-C(＝O)-O]_m”-Y²²In the group represented by (A), m' is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and particularly preferably 1. That is, as represented by the formula- [ Y ]²¹-C(＝O)-O]_m”-Y²²A group represented by the formula-Y is particularly preferred²¹-C(＝O)-O-Y²²-a group represented by (a). Among them, the formula- (CH) is preferred₂)_a’-C(＝O)-O-(CH₂)_b’-a group represented by (a). In the formula, a' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, further preferably 1 or 2, and most preferably 1. b' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, still more preferably 1 or 2, and most preferably 1.

As Ya^x1Preferably a single bond, an ester bond [ -C (═ O) -O-]An ether bond (-O-) -, -C (-O) -NH-, a linear or branched alkylene group, or a combination thereof, and among them, a single bond is particularly preferable.

In the formula (a10-1), Wa^x1Is (n)_ax1+1) a valent aromatic hydrocarbon radical.

As Wa^x1The aromatic hydrocarbon group in (1) may be a group obtained by removing (n) from an aromatic ring_ax1+1) hydrogen atoms. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n +2 pi electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, still more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, phenanthrene, and the like; and an aromatic heterocyclic ring in which a part of carbon atoms constituting the aromatic hydrocarbon ring is substituted with a hetero atom. As aromatic hetero compoundsExamples of the hetero atom in the ring include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.

In the formula (a10-1), n_ax1Is an integer of 1 to 3, preferably 1 or 2, more preferably 1.

Specific examples of the structural unit represented by the general formula (a10-1) are shown below.

In the formula, R^αRepresents a hydrogen atom, a methyl group or a trifluoromethyl group.

[ solution 17]

[ solution 18]

[ solution 19]

[ solution 20]

(A1) The constituent unit (a10) of component (a) may be 1 or 2 or more.

Among the above, the structural unit (a10) is preferably a structural unit having a hydroxystyrene skeleton, and particularly preferably a structural unit represented by the following general formula (a 10-1-0).

[ solution 21]

[ in the formula, R^stRepresents a hydrogen atom or a methyl group. m is₀₁Represents an integer of 1 to 3.]

(A1) The proportion of the structural unit (a10) in the component (a1) is preferably 40 to 80 mol%, more preferably 45 to 75 mol%, and particularly preferably 50 to 70 mol% based on the total (100 mol%) of all the structural units constituting the component (a 1).

By setting the proportion of the structural unit (a10) to be equal to or higher than the lower limit of the preferable range, sensitivity, development characteristics, the effect of suppressing the occurrence of defects, and the like are further improved, while by being equal to or lower than the upper limit of the preferable range, the lithography characteristics such as dimensional uniformity are further improved.

With respect to other structural units

The component (A1) may have other structural units as required in addition to the structural unit (a1) or in addition to the structural unit (a1) and the structural unit (a 10).

As the other structural units, for example, structural units derived from styrene or derivatives thereof; a structural unit (a4) containing an acid-non-dissociable alicyclic group; containing a lactone-containing cyclic group containing-SO₂-a cyclic group or a structural unit containing a carbonate cyclic group (a 2); a structural unit (a3) containing a polar group-containing aliphatic hydrocarbon group (wherein a structural unit belonging to the structural unit (a1) or the structural unit (a2) is not included), and the like.

Structural unit derived from styrene or a derivative thereof (structural unit (st))

"styrene" is a concept including styrene and a concept in which a hydrogen atom at the α -position of styrene is substituted with a substituent such as an alkyl group or a haloalkyl group. Examples of the alkyl group as the substituent include alkyl groups having 1 to 5 carbon atoms, and examples of the haloalkyl group as the substituent include haloalkyl groups having 1 to 5 carbon atoms.

Examples of the "styrene derivative" may include styrene derivatives in which a substituent is bonded to the benzene ring of styrene in which the hydrogen atom at the α -position may be substituted with a substituent.

In addition, the α -position (carbon atom at α -position) means a carbon atom to which a benzene ring is bonded unless otherwise specified.

The "structural unit derived from styrene" and the "structural unit derived from a styrene derivative" mean a structural unit in which an ethylenic double bond of styrene or a styrene derivative is cleaved.

(A1) The constituent (st) of the component (A) may be 1 or 2 or more.

When the component (a1) has the structural unit (st), the proportion of the structural unit (st) is preferably 1 to 30 mol%, more preferably 3 to 25 mol%, and still more preferably 5 to 20 mol% based on the total (100 mol%) of all the structural units constituting the component (a 1).

As to the structural unit (a 4):

the structural unit (a4) is a structural unit containing an acid-non-dissociable alicyclic group.

When the component (a1) has the structural unit (a4), the light transmittance of the resist film can be improved as compared with the case where the component has a structural unit containing an aromatic ring group. In addition, the resist pattern formed has improved dry etching resistance, and in addition, the component (a) has improved hydrophobicity. In particular, in the case of forming a resist pattern by a solvent development process, the improvement of hydrophobicity contributes to the improvement of resolution, resist pattern shape, and the like.

The "acid-non-dissociable cyclic group" in the structural unit (a4) is a cyclic group that does not dissociate and remains in the structural unit directly even by the action of an acid when the acid is generated in the resist composition by exposure (for example, when the acid is generated from the component (B) described later).

The acid-non-dissociable alicyclic group in the structural unit (a4) may be a monocyclic group or a polycyclic group, and is preferably a monocyclic group.

The monocyclic group here is preferably a group obtained by removing 1 or more hydrogen atoms from a monocyclic hydrocarbon. The monocycloalkane is more preferably a monocycloalkane having 3 to 8 carbon atoms, still more preferably a monocycloalkane having 5 to 8 carbon atoms, and specifically includes cyclopentane, cyclohexane, cyclooctane and the like. The polycyclic group is preferably a group obtained by removing 1 or more hydrogen atoms from a polycycloalkane, and the polycycloalkane is preferably a C7-12 polycycloalkane, and specifically includes adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like.

The monocyclic group and the polycyclic group may each have, for example, a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.

The structural unit (a4) may, for example, be a structural unit derived from an acrylate ester in which a hydrogen atom bonded to the carbon atom at the α -position is substituted with a substituent, or a structural unit derived from an acrylamide, and is preferably a structural unit derived from an acrylate ester in which a hydrogen atom bonded to the carbon atom at the α -position is substituted with a substituent.

Specific examples of the structural unit (a4) are shown below.

In the formula, R^αRepresents a hydrogen atom, a methyl group or a trifluoromethyl group.

[ solution 22]

(A1) The constituent unit (a4) of component (a) may be 1 or 2 or more.

Among the above structural units, the structural unit (a4) is preferably a structural unit containing an acid-non-dissociable monocyclic alicyclic group, and more preferably at least one selected from the group consisting of structural units represented by any one of the above chemical formulae (a4-7) to (a 4-10).

(A1) The proportion of the structural unit (a4) in the component (a1) is preferably 1 to 50 mol%, more preferably 2 to 50 mol%, and still more preferably 5 to 45 mol%, based on the total (100 mol%) of all the structural units constituting the component (a 1).

By setting the ratio of the structural unit (a4) to be equal to or higher than the lower limit of the preferable range, the light transmittance of the resist film can be further improved, and high sensitivity and resolution can be further improved. On the other hand, when the upper limit of the preferable range is set to be equal to or lower than the upper limit, balance with other constituent units can be easily obtained.

As to the structural unit (a 2):

(A1) component (b) other than the structural unit (a1) orThe monomer may further contain, in addition to the structural unit (a1) and the structural unit (a10), a lactone ring-containing group and an-SO-containing group as required₂-a cyclic group or a structural unit containing a carbonate cyclic group (a 2).

When the component (A1) is used for forming a resist film, the lactone ring-containing group and the-SO-containing group in the structural unit (a2)₂The cyclic group or the carbonate-containing cyclic group is effective in improving adhesion of the resist film to the substrate. Further, by having the structural unit (a2), the solubility of the resist film in an alkaline developer can be improved at the time of development in the alkaline development process.

The "lactone ring-containing group" refers to a cyclic group containing a ring containing — O — C (═ O) - (lactone ring) in its ring skeleton. The lactone ring is referred to as the first ring, and when the lactone ring is present alone, the lactone ring is referred to as a monocyclic group, and when the lactone ring has another ring structure, the lactone ring is referred to as a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group.

The lactone ring-containing group in the structural unit (a2) is not particularly limited, and any lactone ring-containing group can be used. Specifically, the groups may be represented by the following general formulae (a2-r-1) to (a 2-r-7).

[ solution 23]

[ wherein, Ra'²¹Each independently is a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, -COOR ", -OC (═ O) R", a hydroxyalkyl group or a cyano group; r' is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a-SO-containing group₂-a cyclic group. A' is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (-O-) or a sulfur atom (-S-), an oxygen atom or a sulfur atom. n 'is an integer of 0 to 2, and m' is 0 or 1.]

In the formulae (a2-r-1) to (a2-r-7), Ra'²¹The alkyl group in (1) is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specifically, canExamples thereof include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, and hexyl. Among these, methyl or ethyl is preferable, and methyl is particularly preferable.

As Ra'²¹The alkoxy group in (1) is preferably an alkoxy group having 1 to 6 carbon atoms.

The alkoxy group is preferably linear or branched. Specifically, the Ra 'may be mentioned'²¹Examples of the alkyl group in (1) include those in which an alkyl group is bonded to an oxygen atom (-O-).

As Ra'²¹The halogen atom in (2) may, for example, be a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and preferably a fluorine atom.

As Ra'²¹The haloalkyl group in (1) may be represented by the formula Ra'²¹Wherein a part or all of hydrogen atoms of the alkyl group in (1) are substituted by the halogen atom. The haloalkyl group is preferably a fluoroalkyl group, and particularly preferably a perfluoroalkyl group.

Ra’²¹In the group-COOR ", -OC (. ═ O) R", R "is each a hydrogen atom, an alkyl group, a lactone ring-containing group, a carbonate ring-containing group, or a group containing-SO₂-a cyclic group.

The alkyl group in R' may be linear, branched or cyclic, and the number of carbon atoms is preferably 1 to 15.

When R ″ is a linear or branched alkyl group, the number of carbon atoms is preferably 1 to 10, more preferably 1 to 5, and particularly preferably a methyl group or an ethyl group.

When R' is a cyclic alkyl group, the number of carbon atoms is preferably 3 to 15, more preferably 4 to 12, and still more preferably 5 to 10. Specifically, there can be exemplified a group obtained by removing 1 or more hydrogen atoms from a monocycloparaffin which may be substituted or unsubstituted with a fluorine atom or a fluoroalkyl group; and groups obtained by removing 1 or more hydrogen atoms from a multicycloparaffin such as bicycloalkane, tricycloalkane or tetracycloalkane. More specifically, the compound may include a group obtained by removing 1 or more hydrogen atoms from a monocycloparaffin such as cyclopentane or cyclohexane; and groups obtained by removing 1 or more hydrogen atoms from a polycyclic alkane such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, or the like.

Examples of the lactone ring-containing group in R "may include the same groups as those represented by the general formulae (a2-R-1) to (a 2-R-7).

As the carbonate-containing cyclic group in R', there may be mentioned, in particular, groups represented by the general formulae (ax3-R-1) to (ax3-R-3), respectively, in the same manner as the carbonate-containing cyclic group described later.

As containing-SO in R₂A cyclic group with-SO-containing as described later₂As the cyclic group, there may be mentioned, for example, groups represented by the general formulae (a5-r-1) to (a 5-r-4).

As Ra'²¹The hydroxyalkyl group in (A) is preferably a hydroxyalkyl group having 1 to 6 carbon atoms, and specifically, Ra'²¹Wherein at least 1 of the hydrogen atoms of the alkyl group in (1) is substituted with a hydroxyl group.

In the general formulae (a2-r-2), (a2-r-3) and (a2-r-5), the alkylene group having 1 to 5 carbon atoms in A ″ is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group and an isopropylene group. When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include a group wherein-O-or-S-is interposed between the terminal or carbon atom of the alkylene group, and examples thereof include-O-CH₂-、-CH₂-O-CH₂-、-S-CH₂-、-CH₂-S-CH₂-and the like. A' is preferably an alkylene group having 1 to 5 carbon atoms or-O-, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.

Specific examples of the groups represented by the general formulae (a2-r-1) to (a2-r-7) are shown below.

[ solution 24]

[ solution 25]

"contains-SO₂The term "cyclic group" means a group containing-SO in its ring skeleton₂The cyclic group of the ring of (A) is, in particular, -SO₂The sulfur atom (S) in (E) forms a cyclic group which is part of the ring skeleton of the cyclic group. Will contain-SO in the ring skeleton₂The ring of (a) is counted as the first ring, and is called a monocyclic group in the case of only the ring, and is called a polycyclic group regardless of the structure in the case of having other ring structures. containing-SO₂The cyclic group may be a monocyclic group or a polycyclic group.

containing-SO₂The cyclic group is particularly preferably one containing-O-SO in its ring skeleton₂Cyclic radicals of (i) containing-O-SO₂-O-S-in (a) -forms the cyclic group of the sultone ring forming part of the ring backbone.

As containing-SO₂More specifically, examples of the cyclic group include groups represented by the following general formulae (a5-r-1) to (a 5-r-4).

[ solution 26]

[ wherein, Ra'⁵¹Each independently is a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, -COOR ", -OC (═ O) R", a hydroxyalkyl group or a cyano group. R' is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a-SO-containing group₂-a cyclic group. A' is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom. n' is an integer of 0 to 2.]

In the general formulae (a5-r-1) to (a5-r-2), A 'is the same as A' in the general formulae (a2-r-2), (a2-r-3), and (a 2-r-5).

As Ra'⁵¹Examples of the alkyl group, alkoxy group, halogen atom, haloalkyl group, -COOR ", -OC (═ O) R", and hydroxyalkyl group in (a2-R-1) to (a2-R-7) include Ra'²¹The same groups as exemplified in the description of (1) above.

Specific examples of the groups represented by the general formulae (a5-r-1) to (a5-r-4) are shown below. "Ac" in the formula represents an acetyl group.

[ solution 27]

[ solution 28]

[ solution 29]

The "carbonate-containing cyclic group" refers to a cyclic group containing a ring (carbonate ring) containing — O — C (═ O) -O — in its ring skeleton. The carbonate ring is referred to as the first ring, and when only the carbonate ring is present, the carbonate ring is referred to as a monocyclic group, and when the carbonate ring has another ring structure, the carbonate ring is referred to as a polycyclic group regardless of the structure. The cyclic group containing carbonate may be a monocyclic group or a polycyclic group.

The carbonate-containing cyclic group is not particularly limited, and any carbonate-containing cyclic group can be used. Specifically, the groups may be represented by the following general formulae (ax3-r-1) to (ax 3-r-3).

[ solution 30]

[ wherein, Ra'^x31Each independently is a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, -COOR ", -OC (═ O) R", a hydroxyalkyl group or a cyano group. R' is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a-SO-containing group₂-a cyclic group. A' is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom. p 'is an integer of 0 to 3, and q' is 0 or 1.]

In the general formulae (ax3-r-2) to (ax3-r-3), A 'is the same as A' in the general formulae (a2-r-2), (a2-r-3), and (a 2-r-5).

As Ra'³¹Examples of the alkyl group, alkoxy group, halogen atom, haloalkyl group, -COOR ", -OC (═ O) R", and hydroxyalkyl group in (a2-R-1) to (a2-R-7) include Ra'²¹The same groups as exemplified in the description of (1) above.

Specific examples of the groups represented by the general formulae (ax3-r-1) to (ax3-r-3) are shown below.

[ solution 31]

As the structural unit (a2), among them, a structural unit derived from an acrylate in which a hydrogen atom bonded to a carbon atom at the α -position may be substituted with a substituent is preferable.

As a preferred specific example of the above-mentioned structural unit (a2), a structural unit represented by the following general formula (a2-1) may be mentioned.

[ solution 32]

[ wherein R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms. Ya²¹Is a single bond or a 2-valent linking group. La²¹is-O-, -COO-, -CON (R ') -, -OCO-, -CONHCO-or-CONHCS-, and R' represents a hydrogen atom or a methyl group. Wherein, in La²¹In the case of-O-, Ya²¹Will not be-CO-. Ra²¹Is a lactone ring group-containing, SO-containing₂-a cyclic group or a carbonate-containing cyclic group.]

In the formula (a2-1), R is the same as described above.

R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluoroalkyl group having 1 to 5 carbon atoms, and particularly preferably a hydrogen atom or a methyl group, from the viewpoint of easy industrial availability.

In the formula (a2-1), as Ya²¹A connection of valence 2The linking group is not particularly limited, and a 2-valent hydrocarbon group which may have a substituent, a 2-valent linking group containing a hetero atom, and the like are exemplified as preferable linking groups.

As Ya²¹The 2-valent hydrocarbon group in (a) is exemplified by Va in the above formula (a1-1)¹The same groups as those exemplified in the description of the 2-valent hydrocarbon group in (1). As Ya²¹Examples of the substituent which the 2-valent hydrocarbon group in (b) may have include an alkyl group having 1 to 5 carbon atoms, an alkoxy group, a halogen atom, a haloalkyl group having 1 to 5 carbon atoms, a hydroxyl group, and a carbonyl group.

As Ya²¹Preferred examples of the heteroatom-containing 2-valent linking group in (a) include, for example, -O-, -C (═ O) -, -O-C (═ O) -O-, -C (═ O) -NH-, -NH-C (═ NH) - (H may be substituted by a substituent such as an alkyl group or an acyl group), -S-, -S (═ O)₂-、-S(＝O)₂-O-, of the formula-Y²¹-O-Y²²-、-Y²¹-O-、-Y²¹-C(＝O)-O-、-C(＝O)-O-Y²¹-、-[Y²¹-C(＝O)-O]_m”-Y²²-、-Y²¹-O-C(＝O)-Y²²-or-Y²¹-S(＝O)₂-O-Y²²A group represented by (wherein Y is)²¹And Y²²Each independently represents a 2-valent hydrocarbon group which may have a substituent, O represents an oxygen atom, and m' represents an integer of 0 to 3.]And the like.

In the case where the heteroatom-containing 2-valent linking group is — C (═ O) -NH-, -C (═ O) -NH-C (═ O) -, -NH-C (═ NH) -, H thereof may be substituted with a substituent such as an alkyl group or an acyl group. The number of carbon atoms of the substituent (such as alkyl group or acyl group) is preferably 1 to 10, more preferably 1 to 8, and particularly preferably 1 to 5.

General formula-Y²¹-O-Y²²-、-Y²¹-O-、-Y²¹-C(＝O)-O-、-C(＝O)-O-Y²¹-、-[Y²¹-C(＝O)-O]_m”-Y²²-、-Y²¹-O-C(＝O)-Y²²-or-Y²¹-S(＝O)₂-O-Y²²In (Y)²¹And Y²²Each independently is a 2-valent hydrocarbon group which may have a substituent. The 2-valent hydrocarbon group may, for example, be the 2-valent hydrocarbon groupThe same groups (2-valent hydrocarbon group which may have a substituent) are exemplified in the description of the linking group(s) of (a).

As Y²¹The aliphatic hydrocarbon group is preferably a linear aliphatic hydrocarbon group, more preferably a linear alkylene group, still more preferably a linear alkylene group having 1 to 5 carbon atoms, and particularly preferably a methylene group or an ethylene group.

As Y²²The aliphatic hydrocarbon group is preferably a linear or branched aliphatic hydrocarbon group, and more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.

Is represented by the formula- [ Y ]²¹-C(＝O)-O]_m”-Y²²In the group represented by (A), m' is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and particularly preferably 1. That is, as represented by the formula- [ Y ]²¹-C(＝O)-O]_m”-Y²²A group represented by the formula-Y is particularly preferred²¹-C(＝O)-O-Y²²-a group represented by (a). Among them, the formula- (CH) is preferred₂)_a’-C(＝O)-O-(CH₂)_b’-a group represented by (a). In the formula, a' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, further preferably 1 or 2, and most preferably 1. b' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, still more preferably 1 or 2, and most preferably 1.

As Ya²¹Preferably a single bond, an ester bond [ -C (═ O) -O-]An ether bond (-O-), a linear or branched alkylene group, or a combination thereof.

In the formula (a2-1), La²¹is-O-, -COO-, -CON (R') -, -OCO-, -CONHCO-or-CONHCS-.

R' represents a hydrogen atom or a methyl group.

Wherein, in La²¹In the case of-O-, Ya²¹Will not be-CO-.

In the formula (a2-1), Ra²¹Is a lactone ring group-containing, SO-containing₂-a cyclic group or a carbonate-containing cyclic group.

As Ra²¹In (1), the lactone ring-type group-containing compound contains-SO₂The cyclic group and the carbonate-containing cyclic group are each preferably represented by the above-mentioned general formulae (a2-r-1) to (a2-r-7), the general formulae (a5-r-1) to (a5-r-4), and the general formulae (ax3-r-1) to (ax 3-r-3).

Wherein, Ra²¹Preferably containing a lactone ring group or containing-SO₂A cyclic group, more preferably a group represented by the general formula (a2-r-1), (a2-r-2), (a2-r-6) or (a5-r-1), respectively. More specifically, any of the above-mentioned chemical formulae (r-lc-1-1) to (r-lc-1-7), (r-lc-2-1) to (r-lc-2-18), (r-lc-6-1), (r-sl-1-1), and (r-sl-1-18) is more preferable.

(A1) The constituent unit (a2) of component (a) may be 1 or 2 or more.

When the component (a1) has the structural unit (a2), the proportion of the structural unit (a2) is preferably 1 to 80 mol%, more preferably 3 to 70 mol%, further preferably 5 to 60 mol%, and further preferably 10 to 50 mol% based on the total (100 mol%) of all the structural units constituting the component (a 1).

When the proportion of the structural unit (a2) is equal to or higher than the lower limit of the preferable range, the effect of including the structural unit (a2) can be sufficiently obtained, and when the proportion of the structural unit (a2) is equal to or lower than the upper limit of the preferable range, balance with other structural units can be obtained, and various lithographic characteristics and pattern shapes can be improved.

As to the structural unit (a 3):

the component (a1) may further have a structural unit (A3) containing a polar group-containing aliphatic hydrocarbon group as needed in addition to the structural unit (a1) or in addition to the structural unit (a1) and the structural unit (a10) (wherein the structural unit belonging to any of the structural unit (a0), the structural unit (a1), and the structural unit (a2) is not included).

When the component (a1) has the structural unit (a3), the hydrophilicity of the component (a) is improved, which contributes to improvement of resolution.

Examples of the polar group include a hydroxyl group, a cyano group, a carboxyl group, and a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom, and a hydroxyl group is particularly preferable.

Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group (preferably an alkylene group) having 1 to 10 carbon atoms and a cyclic aliphatic hydrocarbon group (a cyclic group). The cyclic group may be a monocyclic group or a polycyclic group, and may be appropriately selected from cyclic groups which have been mentioned several times among resins for use in a resist composition for ArF excimer laser light, for example. The cyclic group is preferably a polycyclic group, and more preferably has 7 to 30 carbon atoms.

Among these, a structural unit derived from an acrylic ester containing an aliphatic polycyclic group containing a hydroxyl group, a cyano group, a carboxyl group, or a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom is more preferable. Examples of the polycyclic group include groups obtained by removing 2 or more hydrogen atoms from a bicycloalkane, tricycloalkane, tetracycloalkane, or the like. Specifically, the compound may be one obtained by removing 2 or more hydrogen atoms from a polycyclic alkane such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, or the like. Among these polycyclic groups, industrially preferred are groups obtained by removing 2 or more hydrogen atoms from adamantane, groups obtained by removing 2 or more hydrogen atoms from norbornane, and groups obtained by removing 2 or more hydrogen atoms from tetracyclododecane.

The structural unit (a3) is not particularly limited as long as it contains a polar group-containing aliphatic hydrocarbon group, and any structural unit can be used.

As the structural unit (a3), a structural unit derived from an acrylate in which a hydrogen atom bonded to a carbon atom at the α -position may be substituted with a substituent is preferable, and is a structural unit containing an aliphatic hydrocarbon group containing a polar group.

The structural unit (a3) is preferably a structural unit derived from hydroxyethyl acrylate when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms, and when the hydrocarbon group is a polycyclic group, it is preferably a structural unit represented by the following formula (a3-1), a structural unit represented by the following formula (a3-2), or a structural unit represented by the following formula (a 3-3).

[ solution 33]

[ wherein R is the same as above, j is an integer of 1 to 3, k is an integer of 1 to 3, t' is an integer of 1 to 3, l is an integer of 1 to 5, and s is an integer of 1 to 3. ]

In the formula (a3-1), j is preferably 1 or 2, and more preferably 1. In the case where j is 2, it is preferable that hydroxyl groups are bonded to the 3-and 5-positions of the adamantyl group. When j is 1, a hydroxyl group is preferably bonded to the 3-position of the adamantyl group.

j is preferably 1, and particularly preferably a hydroxyl group is bonded to the 3-position of the adamantyl group.

In the formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5-or 6-position of the norbornyl group.

In the formula (a3-3), t' is preferably 1. l is preferably 1. s is preferably 1. They are preferably bonded with 2-norbornyl or 3-norbornyl at the terminal of the carboxyl group of acrylic acid. The fluoroalkyl alcohol is preferably bonded to the 5 or 6 position of the norbornyl group.

(A1) The constituent unit (a3) of component (a) may be 1 or 2 or more.

When the component (a1) has the structural unit (A3), the proportion of the structural unit (A3) is preferably 1 to 50 mol%, more preferably 3 to 40 mol%, further preferably 5 to 30 mol%, and particularly preferably 10 to 30 mol% based on the total (100 mol%) of all the structural units constituting the component (a 1).

By setting the ratio of the structural unit (a3) to a preferred lower limit or more, the resolution in forming a resist pattern is further improved. On the other hand, by setting the upper limit value to a preferable value or less, balance with other constituent units is more easily achieved.

In the resist composition of the present embodiment, the resin component as the component (a1) is preferably a resin component containing a polymer compound having the structural unit (a 1). As the polymer compound having the structural unit (a1), a polymer compound having the structural unit (a1) and the structural unit (a10), and a polymer compound having the structural unit (a1), the structural unit (a10), and the structural unit (st) can be preferably exemplified.

(A1) The weight average molecular weight (Mw) of the component (B) is preferably 5000 to 30000, more preferably 6000 to 25000, and still more preferably 10000 to 20000 (in terms of polystyrene equivalent by Gel Permeation Chromatography (GPC)).

When the Mw of the component (a1) is not more than the upper limit of the above preferable range, the viscosity of the resist composition is easily suppressed from being excessively high. Further, the resist composition has sufficient solubility in a resist solvent when used as a resist, and when the solubility is not less than the lower limit of the above preferable range, a resist film having a high film thickness can be easily formed. Further, the dry etching resistance and the cross-sectional shape of the resist pattern are further improved.

(A1) The molecular weight distribution coefficient (Mw/Mn) of the component (B) is not particularly limited, but is preferably 1.0 to 4.0, more preferably 1.0 to 3.0, and particularly preferably 1.5 to 2.5. In addition, Mn represents a number average molecular weight.

(A1) The ingredients can be manufactured, for example, in the following manner: a monomer from which the structural unit (a1) is derived, a monomer from which the structural unit (a10) is derived (a monomer in which at least a part of hydrogen atoms in hydroxyl groups bonded to a benzene ring is protected), and a monomer from which other structural units are derived as necessary are dissolved in a polymerization solvent, and herein, a radical polymerization initiator such as Azobisisobutyronitrile (AIBN), dimethyl azobisisobutyrate (e.g., V-601), or the like is added thereto to perform polymerization, followed by deprotection reaction.

In addition, in the polymerization, HS-CH may be used in combination, for example₂-CH₂-CH₂-C(CF₃)₂A chain transfer agent such as-OH to introduce-C (CF) at the terminal₃)₂-OH groups. Thus, the copolymer of the hydroxyalkyl group in which a part of the hydrogen atoms of the alkyl group is substituted with the fluorine atom is effective in reducing development defects and LER (line edge roughness: uneven line side wall).

The component (a1) contained in the resist composition may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

(A) The proportion of the component (a1) in the component (a) is preferably 25% by mass or more, more preferably 50% by mass or more, further preferably 75% by mass or more, and may be 100% by mass, based on the total mass of the component (a). When the ratio of the component (a1) is equal to or higher than the lower limit of the above-described preferable range, a resist pattern having a good shape and excellent in sensitivity, resolution, dimensional uniformity (CDU) in the support surface (Shot), and other lithographic characteristics can be easily formed.

In the resist composition of the present embodiment, the component (a) is a resin component whose solubility in a developer changes by the action of an acid, and may contain a resin component other than the component (a 1).

The content of the component (a) in the resist composition of the present embodiment may be appropriately adjusted according to the thickness of a resist film to be formed, and the like.

(B) component(s)

(B) The component (C) is an acid generator component which generates an acid by exposure. In the resist composition of the present embodiment, the component (B) includes an acid generator (B1) (hereinafter also referred to as a component (B1)) composed of a compound represented by the general formula (B1-1).

With respect to the (B1) component

(B1) Component (b) is an acid generator comprising a compound represented by the following general formula (b 1-1).

That is, the component (B1) is a monoaryl acid generator.

[ chemical 34]

[ in the formula, R^b1Is an aryl group which may have a substituent. R^b2And R^b3Each independently is an aliphatic hydrocarbon group. R^b2And R^b3May be bonded to each other to form a ring structure. L is^b1、L^b2And L^b3Each independently is a 2-valent linking group or a single bond. X^-Is a counter anion.]

The formula (b1-1) In, R^b1Is an aryl group which may have a substituent.

As R^b1Examples of the aryl group in (1) include aryl groups having 6 to 20 carbon atoms, and phenyl and naphthyl groups are preferable.

As R^b1Examples of the substituent which may be present include alkyl groups, halogen atoms, haloalkyl groups, carbonyl groups, cyano groups, amino groups, aryl groups, and groups represented by the following formulae (ca-r-1) to (ca-r-8).

[ solution 35]

[ wherein R'²⁰¹Each independently represents a hydrogen atom, a cyclic group which may have a substituent, a linear alkyl group which may have a substituent, or a linear alkenyl group which may have a substituent.]

A cyclic group which may have a substituent:

the cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromatic character. The aliphatic hydrocarbon group may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, and a saturated aliphatic hydrocarbon group is generally preferred.

R’²⁰¹The aromatic hydrocarbon group in (1) is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, still more preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and most preferably 6 to 10 carbon atoms. Wherein the number of carbons does not include the number of carbons in the substituent.

As R'²⁰¹The aromatic ring of the aromatic hydrocarbon group in (3) may, specifically, be benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, or an aromatic heterocycle in which a part of carbon atoms constituting these aromatic rings is substituted with a hetero atom.

Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom.

As R'²⁰¹The aromatic hydrocarbon group in (1) may be, specificallyExamples thereof include a group obtained by removing 1 hydrogen atom from the aromatic ring (for example, an aryl group such as a phenyl group and a naphthyl group), a group obtained by substituting 1 hydrogen atom of the aromatic ring with an alkylene group (for example, an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group and a 2-naphthylethyl group), and the like. The alkylene group (alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

R’²⁰¹The cyclic aliphatic hydrocarbon group in (2) may be an aliphatic hydrocarbon group having a ring in the structure.

Examples of the aliphatic hydrocarbon group having a ring in its structure include an alicyclic hydrocarbon group (a group obtained by removing 1 hydrogen atom from an aliphatic hydrocarbon ring), a group obtained by bonding an alicyclic hydrocarbon group to the end of a linear or branched aliphatic hydrocarbon group, and a group in which an alicyclic hydrocarbon group is interposed between linear or branched aliphatic hydrocarbon groups.

The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.

The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing 1 or more hydrogen atoms from a monocycloparaffin. The monocycloalkane is preferably a monocycloalkane having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing 1 or more hydrogen atoms from a polycyclic hydrocarbon, and the polycyclic alkane is preferably a polycyclic alkane having 7 to 30 carbon atoms. Among these, as the polycyclic alkane, polycyclic alkanes having a polycyclic skeleton with a crosslinked ring, such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane, are more preferable; polycyclic alkanes having a polycyclic skeleton of condensed rings, such as cyclic groups having a steroid skeleton.

Wherein, R'²⁰¹The cyclic aliphatic hydrocarbon group in (1) is preferably a group obtained by removing 1 or more hydrogen atoms from a monocycloparaffin or polycycloalkane, more preferably a group obtained by removing 1 hydrogen atom from a polycycloalkane, particularly preferably an adamantyl group or norbornyl group, and most preferably an adamantyl group。

The straight or branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms.

The linear aliphatic hydrocarbon group is preferably a linear alkylene group, and specifically, it may, for example, be methylene [ -CH ]₂-]Ethylene [ - (CH)₂)₂-]Propylene [ - (CH)₂)₃-]Butylene [ - (CH)₂)₄-]- (CH) pentylene [ - (CH)₂)₅-]And the like.

The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specifically may, for example, be-CH (CH)₃)-、-CH(CH₂CH₃)-、-C(CH₃)₂-、-C(CH₃)(CH₂CH₃)-、-C(CH₃)(CH₂CH₂CH₃)-、-C(CH₂CH₃)₂-isoalkylmethylene; -CH (CH)₃)CH₂-、-CH(CH₃)CH(CH₃)-、-C(CH₃)₂CH₂-、-CH(CH₂CH₃)CH₂-、-C(CH₂CH₃)₂-CH₂-isoalkylethylene; -CH (CH)₃)CH₂CH₂-、-CH₂CH(CH₃)CH₂-isoalkylpropylene; -CH (CH)₃)CH₂CH₂CH₂-、-CH₂CH(CH₃)CH₂CH₂An alkylalkylene group such as an alkylbutylene group, etc. The alkyl group in the alkyl alkylene group is preferably a straight-chain alkyl group having 1 to 5 carbon atoms.

Furthermore, R'²⁰¹The cyclic hydrocarbon group in (2) may contain a hetero atom like a heterocycle and the like. Specifically, examples thereof include lactone ring-containing groups represented by the general formulae (a2-r-1) to (a2-r-7) and-SO-containing groups represented by the general formulae (a5-r-1) to (a5-r-4)₂A cyclic group and other heterocyclic groups represented by the following chemical formulae (r-hr-1) to (r-hr-16).

[ solution 36]

As R'²⁰¹Examples of the substituent in the cyclic group (b) include an alkyl group, an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, a carbonyl group, and a nitro group.

The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.

The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and a tert-butoxy group, and most preferably a methoxy group or an ethoxy group.

Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.

Examples of the haloalkyl group as a substituent include alkyl groups having 1 to 5 carbon atoms, for example, groups in which some or all of hydrogen atoms such as methyl, ethyl, propyl, n-butyl, and tert-butyl are substituted with the above-mentioned halogen atom.

The carbonyl group as the substituent is a methylene group (-CH) substituted for the cyclic hydrocarbon group₂-) of (a) a group of (b).

Chain alkyl group which may have a substituent:

as R'²⁰¹The chain alkyl group of (b) may be either linear or branched.

The straight-chain alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, examples thereof include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, isotridecyl, tetradecyl, pentadecyl, hexadecyl, isohexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl and docosyl.

The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specific examples thereof include 1-methylethyl, 1-methylpropyl, 2-methylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl and 4-methylpentyl.

Chain alkenyl group which may have a substituent:

as R'²⁰¹The chain alkenyl group (b) may be either straight or branched, and the number of carbon atoms is preferably 2 to 10, more preferably 2 to 5, still more preferably 2 to 4, and particularly preferably 3. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched alkenyl group include a 1-methylethenyl group, a 2-methylethenyl group, a 1-methylpropenyl group and a 2-methylpropenyl group.

Among the above, the linear alkenyl group is preferably a linear alkenyl group, more preferably a vinyl group or a propenyl group, and particularly preferably a vinyl group.

As R'²⁰¹Examples of the substituent in the chain alkyl group or the chain alkenyl group of (1) may include an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group and the above-mentioned R'²⁰¹Cyclic group in (1), and the like.

R’²⁰¹Examples of the cyclic group which may have a substituent or the chain alkyl group which may have a substituent other than those described above may include the same groups as the acid-dissociable group represented by the above formula (a 1-r-2).

Wherein R'²⁰¹A group represented by the formula (ca-r-1) is preferred.

In the formula (b1-1), R^b2And R^b3Each independently is an aliphatic hydrocarbon group. R^b2And R^b3The aliphatic hydrocarbon group in (2) may be a linear or cyclic one, and examples thereof include linear or cyclic alkyl groups and alkenyl groups.

The chain or cyclic alkyl group is preferably an alkyl group having 1 to 30 carbon atoms.

The alkenyl group herein is preferably an alkenyl group having 2 to 10 carbon atoms.

R^b2And R^b3Can be bonded to each other to form a ring junctionAnd (5) forming. When they are bonded to each other to form a ring together with the sulfur atom in the formula, they may be bonded to each other via a hetero atom such as a sulfur atom, oxygen atom, nitrogen atom or the like, or a carbonyl group, -SO-, -SO₂-、-SO₃-, -COO-, -CONH-or-N (R)_N) - (the R)_NAlkyl group having 1 to 5 carbon atoms) and the like. The ring to be formed is preferably a three-to ten-membered ring in which 1 ring including the sulfur atom in the formula in the ring skeleton includes a sulfur atom, and particularly preferably a five-to seven-membered ring. Specific examples of the ring to be formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a thianthrene ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thioxanthone ring, a thianthrene ring, a phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

In the formula (b1-1), L^b1、L^b2And L^b3Each independently is a 2-valent linking group or a single bond.

As L^b1、L^b2And L^b3The linking group having a valence of 2 in (a) may be, independently, represented by-C (═ O) -, -C (═ O) -O-, -O-C (═ O) -, arylene, alkylene or alkenylene.

L^b1、L^b2And L^b3The arylene group in (b) may be a group obtained by further removing 1 hydrogen atom from an aryl group, and is preferably a group obtained by removing 2 hydrogen atoms from an aromatic ring (e.g., benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, or an aromatic heterocycle in which a part of carbon atoms constituting these aromatic rings is substituted with a hetero atom).

L^b1、L^b2And L^b3The alkylene group or alkenylene group in (1) may be exemplified by the group R'²⁰¹The group exemplified as the chain alkyl group or the chain alkenyl group in (1) is a group obtained by further removing 1 hydrogen atom. Specifically, the alkyl group may be a group obtained by further removing 1 hydrogen atom from a linear alkyl group having 1 to 20 carbon atoms or a group obtained by further removing 1 hydrogen atom from a branched alkyl group having 3 to 20 carbon atoms.

L in the formula (b1-1) is L because the acid generation efficiency by exposure can be further improved^b1Preferably, it isA single bond.

The cation portion of the component (B1) may more preferably be a cation represented by the following general formula (ca-1-01) or a cation represented by the following general formula (ca-1-02).

Particularly preferred is a cation represented by the general formula (ca-1-01).

[ solution 37]

[ in the formula, R^b11And R^b12Each independently is an aryl group which may have a substituent. L is^b11is-C (═ O) -or-C (═ O) -O-. R^b121And R^b122Each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. nb1 is an integer of 1 to 3. nb2 is an integer of 1 to 3.]

In the formula, R^b11And R^b12Are respectively reacted with R in the formula (b1-1)^b1The same is true. Among them, unsubstituted aryl groups are preferred. Preferred aryl groups include phenyl and naphthyl. Among these, phenyl is more preferable, that is, monophenyl-type acid generators are more preferable.

R^b121And R^b122Each of which is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom, a methyl group or an ethyl group, more preferably a hydrogen atom.

nb1 is an integer of 1 to 3, preferably 1 or 2, more preferably 2.

nb2 is an integer of 1 to 3, preferably 1 or 2, more preferably 1.

As the cation represented by the general formula (ca-1-01), preferred are cations represented by the following chemical formulae (ca-1-104) to (ca-1-129), respectively, and among these, more preferred are a cation represented by the chemical formula (ca-1-104) and a cation (R) represented by the chemical formula (ca-1-105) "²⁰¹In the case of a hydrogen atom).

As the cation represented by the general formula (ca-1-02), a cation represented by the following chemical formula (ca-1-102) or a cation represented by the following chemical formula (ca-1-103) is preferable.

[ solution 38]

[ in the formula, R "²⁰¹Is a hydrogen atom or a substituent, and as such a substituent, with the R as mentioned^b1Illustrative examples of the substituent may include the same ones.]

[ solution 39]

[ solution 40]

In the formula (b1-1), X^-Is a counter anion.

As the X^-The acid generator component used in the resist composition may be any one of a variety of acid generators, including, but not limited to, an acid generator component, a metal component, and the like.

For example, as X^-Examples thereof include an anion represented by the following general formula (b1-1-an1), an anion represented by the following general formula (b1-1-an2), and an anion represented by the following general formula (b1-1-an 3).

[ solution 41]

[ in the formula, R¹⁰¹And R¹⁰⁴～R¹⁰⁸Each independently represents a cyclic group which may have a substituent, a linear alkyl group which may have a substituent, or a linear alkenyl group which may have a substituent. R¹⁰⁴And R¹⁰⁵May be bonded to each other to form a ring structure. R¹⁰²Is a fluorinated alkyl group having 1 to 5 carbon atoms or a fluorine atom. Y is¹⁰¹Is a 2-valent linking group containing an oxygen atom or a single bond. V¹⁰¹～V¹⁰³Each independently a single bond, alkylene, or fluoroalkylene. L is¹⁰¹～L¹⁰²Each independently a single bond or an oxygen atom. L is¹⁰³～L¹⁰⁵Each independently of the other being a single bond, -CO-or-SO₂-。]

An anion represented by the general formula (b1-1-an1)

In the formula (b1-1-an1), R¹⁰¹The alkyl group may be a cyclic group which may have a substituent, a linear alkyl group which may have a substituent, or a linear alkenyl group which may have a substituent.

A cyclic group which may have a substituent:

the cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromatic character. The aliphatic hydrocarbon group may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, and a saturated aliphatic hydrocarbon group is generally preferred.

R¹⁰¹The aromatic hydrocarbon group in (1) is a hydrocarbon group having an aromatic ring. The number of carbon atoms of the aromatic hydrocarbon group is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 10. Wherein the number of carbons does not include the number of carbons in the substituent.

As R¹⁰¹The aromatic ring of the aromatic hydrocarbon group in (3) may, specifically, be benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, or an aromatic heterocycle in which a part of carbon atoms constituting these aromatic rings is substituted with a hetero atom. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom.

As R¹⁰¹Specific examples of the aromatic hydrocarbon group in (1) include a group obtained by removing 1 hydrogen atom from the aromatic ring (an aryl group: e.g., a phenyl group or a naphthyl group), and a group obtained by substituting 1 hydrogen atom of the aromatic ring with an alkylene group (e.g., an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group or a 2-naphthylethyl group). The number of carbon atoms of the alkylene group (alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

R¹⁰¹The cyclic aliphatic hydrocarbon group in (2) may be an aliphatic hydrocarbon group having a ring in the structure.

Examples of the aliphatic hydrocarbon group having a ring in its structure include an alicyclic hydrocarbon group (a group obtained by removing 1 hydrogen atom from an aliphatic hydrocarbon ring), a group obtained by bonding an alicyclic hydrocarbon group to the end of a linear or branched aliphatic hydrocarbon group, and a group in which an alicyclic hydrocarbon group is interposed between linear or branched aliphatic hydrocarbon groups.

The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.

The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing 1 or more hydrogen atoms from a monocycloparaffin. The monocycloalkane is preferably a monocycloalkane having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing 1 or more hydrogen atoms from a polycyclic hydrocarbon, and the polycyclic alkane is preferably a polycyclic alkane having 7 to 30 carbon atoms. Among these, as the polycyclic alkane, polycyclic alkanes having a polycyclic skeleton with a crosslinked ring, such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane, are more preferable; polycyclic alkanes having a polycyclic skeleton of condensed rings, such as cyclic groups having a steroid skeleton.

Wherein, as R¹⁰¹The cyclic aliphatic hydrocarbon group in (1) is preferably a group obtained by removing 1 or more hydrogen atoms from a monocycloalkane or polycycloalkane, more preferably a group obtained by removing 1 hydrogen atom from a polycycloalkane, particularly preferably an adamantyl group or norbornyl group, and most preferably an adamantyl group.

The number of carbon atoms of the straight-chain aliphatic hydrocarbon group that can be bonded to the alicyclic hydrocarbon group is preferably 1 to 10, more preferably 1 to 6, even more preferably 1 to 4, and most preferably 1 to 3. The linear aliphatic hydrocarbon group is preferably a linear alkylene group, and specifically, it may, for example, be methylene [ -CH ]₂-]Ethylene [ - (CH)₂)₂-]Propylene [ - (CH)₂)₃-]Butylene [ - (CH)₂)₄-]- (CH) pentylene [ - (CH)₂)₅-]And the like.

Of branched aliphatic hydrocarbon groups which may be bonded to alicyclic hydrocarbon groupsThe carbon number is preferably 2 to 10, more preferably 3 to 6, further preferably 3 or 4, and most preferably 3. The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specifically may, for example, be-CH (CH)₃)-、-CH(CH₂CH₃)-、-C(CH₃)₂-、-C(CH₃)(CH₂CH₃)-、-C(CH₃)(CH₂CH₂CH₃)-、-C(CH₂CH₃)₂-isoalkylmethylene; -CH (CH)₃)CH₂-、-CH(CH₃)CH(CH₃)-、-C(CH₃)₂CH₂-、-CH(CH₂CH₃)CH₂-、-C(CH₂CH₃)₂-CH₂-isoalkylethylene; -CH (CH)₃)CH₂CH₂-、-CH₂CH(CH₃)CH₂-isoalkylpropylene; -CH (CH)₃)CH₂CH₂CH₂-、-CH₂CH(CH₃)CH₂CH₂An alkylalkylene group such as an alkylbutylene group, etc. The alkyl group in the alkyl alkylene group is preferably a straight-chain alkyl group having 1 to 5 carbon atoms.

Furthermore, R¹⁰¹The cyclic hydrocarbon group in (2) may contain a hetero atom like a heterocycle and the like. Specifically, examples thereof include lactone ring-containing groups represented by the general formulae (a2-r-1) to (a2-r-7) and-SO-containing groups represented by the general formulae (a5-r-1) to (a5-r-4)₂A cyclic group and other heterocyclic groups represented by the above chemical formulas (r-hr-1) to (r-hr-16).

As R¹⁰¹Examples of the substituent in the cyclic group (b) include an alkyl group, an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, a carbonyl group, and a nitro group.

The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.

The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, and a tert-butoxy group, and most preferably a methoxy group or an ethoxy group.

Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.

Examples of the haloalkyl group as a substituent include alkyl groups having 1 to 5 carbon atoms, for example, groups in which some or all of hydrogen atoms such as methyl, ethyl, propyl, n-butyl, and tert-butyl are substituted with the above-mentioned halogen atom.

The carbonyl group as the substituent is a methylene group (-CH) substituted for the cyclic hydrocarbon group₂-) of (a) a group of (b).

Chain alkyl group which may have a substituent:

as R¹⁰¹The chain alkyl group of (b) may be either linear or branched.

The straight-chain alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, examples thereof include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, isotridecyl, tetradecyl, pentadecyl, hexadecyl, isohexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl and docosyl.

The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specific examples thereof include 1-methylethyl, 1-methylpropyl, 2-methylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl and 4-methylpentyl.

Chain alkenyl group which may have a substituent:

as R¹⁰¹The chain alkenyl group (b) may be either straight-chain or branched, and the number of carbon atoms is preferably 2 to 10, more preferably 2 to 5, still more preferably 2 to 4, and particularly preferably 3. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched alkenyl group include a 1-methylethenyl group, a 2-methylethenyl group, a 1-methylpropenyl group and a 2-methylpropenyl group.

Among the above, the linear alkenyl group is preferably a linear alkenyl group, more preferably a vinyl group or a propenyl group, and particularly preferably a vinyl group.

As R¹⁰¹Examples of the substituent in the linear alkyl group or the linear alkenyl group of (3) include an alkoxy group, a halogen atom, a haloalkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, and the above-mentioned R¹⁰¹Cyclic group in (1), and the like.

In the above, R¹⁰¹The cyclic group may have a substituent, and more preferably a cyclic hydrocarbon group may have a substituent. More specifically, the following is preferable: groups obtained by removing 1 or more hydrogen atoms from phenyl, naphthyl, or polycycloalkane; lactone ring-containing groups represented by the general formulae (a2-r-1) to (a2-r-7), respectively; containing-SO represented by the general formulae (a5-r-1) to (a5-r-4) respectively₂-cyclic groups, etc.

In the formula (b1-1-an1), Y¹⁰¹Is a 2-valent linking group comprising a single bond or an oxygen atom.

At Y¹⁰¹In the case of a 2-valent linking group containing an oxygen atom, Y¹⁰¹Atoms other than oxygen atoms may be contained. Examples of the atom other than the oxygen atom include a carbon atom, a hydrogen atom, a sulfur atom, and a nitrogen atom.

Examples of the 2-valent linking group containing an oxygen atom include non-hydrocarbon oxygen atom-containing linking groups such as an oxygen atom (ether bond: -O-), an ester bond (-C (═ O) -O-), an oxycarbonyl (-O-C (═ O) -), an amide bond (-C (═ O) -NH-), a carbonyl (-C (═ O) -), and a carbonate bond (-O-C (═ O) -O-; combinations of the non-hydrocarbon oxygen atom-containing linking groups and alkylene groups, and the like. In the combination, a sulfonyl group (-SO) may be further bonded₂-). Examples of the above-mentioned linking group having a valence of 2 and containing an oxygen atom may include linking groups represented by the following general formulae (y-al-1) to (y-al-7).

[ solution 42]

[ in the formula, V'¹⁰¹Is a single bond or C1-5 alkylene group, V'¹⁰²Is a C1-30 saturated hydrocarbon group with a valence of 2.]

V’¹⁰²The 2-valent saturated hydrocarbon group in (1) is preferably an alkylene group having 1 to 30 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, and still more preferably an alkylene group having 1 to 5 carbon atoms.

As V'¹⁰¹And V'¹⁰²The alkylene group in (b) may be a linear alkylene group or a branched alkylene group, and is preferably a linear alkylene group.

As V'¹⁰¹And V'¹⁰²The alkylene group in (1) is specifically exemplified by methylene [ -CH ]₂-]；-CH(CH₃)-、-CH(CH₂CH₃)-、-C(CH₃)₂-、-C(CH₃)(CH₂CH₃)-、-C(CH₃)(CH₂CH₂CH₃)-、-C(CH₂CH₃)₂-isoalkylmethylene; ethylene [ -CH₂CH₂-]；-CH(CH₃)CH₂-、-CH(CH₃)CH(CH₃)-、-C(CH₃)₂CH₂-、-CH(CH₂CH₃)CH₂-isoalkylethylene; propylene (n-propylene) [ -CH₂CH₂CH₂-]；-CH(CH₃)CH₂CH₂-、-CH₂CH(CH₃)CH₂-isoalkylpropylene; butylene [ -CH₂CH₂CH₂CH₂-]；-CH(CH₃)CH₂CH₂CH₂-、-CH₂CH(CH₃)CH₂CH₂-isoalkylbutylene; pentylene [ -CH₂CH₂CH₂CH₂CH₂-]And the like.

Furthermore, V'¹⁰¹Or V'¹⁰²In the alkylene group, a part of methylene groups may be substituted with a 2-valent alicyclic group having 5 to 10 carbon atoms. The aliphatic cyclic group is preferably derived from Ra 'of the formula (a 1-r-1)'³1 of the cyclic aliphatic hydrocarbon group (monocyclic alicyclic hydrocarbon group, polycyclic alicyclic hydrocarbon group) is further removedThe 2-valent group derived from a hydrogen atom is more preferably cyclohexylene, 1, 5-adamantylene or 2, 6-adamantylene.

As Y¹⁰¹The linking group having a valence of 2 and containing an ester bond or the linking group having a valence of 2 and containing an ether bond are preferable, and the linking groups represented by the above formulae (y-al-1) to (y-al-5) are more preferable.

In the formula (b1-1-an1), V¹⁰¹Is a single bond, alkylene or fluoroalkylene. V¹⁰¹The alkylene group and the fluoroalkylene group in (1) preferably have 1 to 4 carbon atoms. As V¹⁰¹The fluoroalkylene group in (1) may, for example, be V¹⁰¹Wherein a part or all of hydrogen atoms of the alkylene group in (1) are substituted by fluorine atoms. Wherein, V¹⁰¹Preferably a single bond or a C1-4 fluoroalkylene group.

In the formula (b1-1-an1), R¹⁰²Is a fluorine atom or a fluoroalkyl group having 1 to 5 carbon atoms. R¹⁰²Preferably a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms, more preferably a fluorine atom.

As a specific example of the anion portion represented by the above formula (b1-1-an1), for example, in Y¹⁰¹Examples of the "single bond" may include fluoroalkylsulfonate anions such as trifluoromethanesulfonate anion and perfluorobutane sulfonate anion; at Y¹⁰¹In the case of a linking group having a valence of 2 and containing an oxygen atom, an anion represented by any one of the following formulae (an-1) to (an-3) may be mentioned.

[ solution 43]

[ in the formula, R "¹⁰¹Is an alicyclic group which may have a substituent, a group represented by the above formulae (r-hr-1) to (r-hr-6), or a chain alkyl group which may have a substituent; r'¹⁰²Is an aliphatic cyclic group which may have a substituent, a lactone-containing cyclic group represented by the general formulae (a2-r-1) to (a2-r-7) or an-SO-containing cyclic group represented by the general formulae (a5-r-1) to (a5-r-4)₂-a cyclic group; r'¹⁰³Is an aromatic cyclic group which may have a substituent(s), may haveAn alicyclic group having a substituent, or a linear alkenyl group having a substituent; v 'is an integer of 0 to 3, q' is an integer of 1 to 20, t 'is an integer of 1 to 3, and n' is 0 or 1.]

R”¹⁰¹、R”¹⁰²And R "¹⁰³The alicyclic group which may have a substituent(s) is preferably as the R¹⁰¹The cyclic aliphatic hydrocarbon group in (1) is exemplified. The substituent may, for example, be represented by the formula¹⁰¹The same groups as those in (1) may be substituted for the substituents of the cyclic aliphatic hydrocarbon group.

R”¹⁰³The aromatic cyclic group which may have a substituent(s) in (1) is preferably the R¹⁰¹Examples of the aromatic hydrocarbon group in the cyclic hydrocarbon group in (1) are given. The substituent may, for example, be represented by the formula¹⁰¹The same substituents as those in (1) may be substituted for the aromatic hydrocarbon group.

R”¹⁰¹The chain alkyl group which may have a substituent(s) in (1) is preferably the R group¹⁰¹The chain alkyl group in (1) above. R'¹⁰³The optionally substituted chain alkenyl group in (1) is preferably the R group¹⁰¹The chain alkenyl group in (1) is exemplified.

An anion represented by the general formula (b1-1-an2)

In the formula (b1-1-an2), R¹⁰⁴、R¹⁰⁵Each of which is independently a cyclic group which may have a substituent, a linear alkyl group which may have a substituent, or a linear alkenyl group which may have a substituent, is exemplified by R in the formula (b1-1-an1)¹⁰¹The same groups. Wherein R is¹⁰⁴、R¹⁰⁵May be bonded to each other to form a ring.

R¹⁰⁴、R¹⁰⁵The alkyl group is preferably a chain alkyl group which may have a substituent, more preferably a linear or branched alkyl group or a linear or branched fluoroalkyl group.

The chain alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 7 carbon atoms, and still more preferably 1 to 3 carbon atoms. R is also good in solubility in a solvent for a resist, and the like¹⁰⁴、R¹⁰⁵Carbon number of chain alkyl group of (2)In the above range of carbon number, the smaller the carbon number, the better. Furthermore, R¹⁰⁴、R¹⁰⁵The larger the number of hydrogen atoms substituted with fluorine atoms in the chain alkyl group (2) is, the stronger the acid strength is and the transparency to high-energy light of 250nm or less and electron beams is improved, and thus the chain alkyl group is preferable.

The proportion of fluorine atoms in the chain alkyl group, that is, the fluorination rate, is preferably 70 to 100%, more preferably 90 to 100%, and most preferably a perfluoroalkyl group in which all hydrogen atoms are substituted with fluorine atoms.

In the formula (b1-1-an2), V¹⁰²、V¹⁰³Each independently a single bond, an alkylene group or a fluoroalkylene group, and are each exemplified by a group V of the formula (b1-1-an1)¹⁰¹The same groups.

In the formula (b1-1-an2), L¹⁰¹、L¹⁰²Each independently a single bond or an oxygen atom.

An anion represented by the general formula (b1-1-an3)

In the formula (b1-1-an3), R¹⁰⁶～R¹⁰⁸Each of which is independently a cyclic group which may have a substituent, a linear alkyl group which may have a substituent, or a linear alkenyl group which may have a substituent, is exemplified by R in the formula (b1-1-an1)¹⁰¹The same groups.

In the formula (b1-1-an3), L¹⁰³～L¹⁰⁵Each independently of the other being a single bond, -CO-or-SO₂-。

In the formula (b1-1), X^-May be R¹⁰⁹-SO₃ ^-. Herein, R is¹⁰⁹Examples of the "cyclic group" which may have a substituent(s), "linear alkyl group which may have a substituent(s)" or "linear alkenyl group which may have a substituent(s)" may include R in the above-mentioned formula (b1-1-an1)¹⁰¹The same groups. Wherein R is¹⁰⁹Wherein a fluorine atom is bonded to a carbon atom adjacent to the S atom.

In the formula (b1-1), X^-May be a halide anion. The halogen anion may, for example, be a fluoride ion, a chloride ion, a bromide ion or an iodide ion.

Among the above, the anion portion of the component (B1) is preferably an anion represented by the general formula (B1-1-an 1). Among these, anions represented by any of the above general formulae (an-1) to (an-3) are more preferable, and anions represented by any of the general formulae (an-1) and (an-2) are still more preferable.

(B1) The acid generator may be used alone in 1 kind or in combination of 2 or more kinds.

The component (B1) in the present embodiment is particularly preferably a compound represented by the following general formula (B1-10).

[ solution 44]

[ in the formula, R¹⁰¹、Y¹⁰¹、V¹⁰¹And R¹⁰²Are respectively linked with R in the formula (b1-1-an1)¹⁰¹、Y¹⁰¹、V¹⁰¹And R¹⁰²The same is true. R^b11And nb1 is each independently substituted with R in the formula (ca-1-01)^b11And nb 1.]

Specific examples of the preferable component (B1) are described below.

[ solution 45]

In the resist composition of the present embodiment, 1 kind of the component (B1) may be used alone, or 2 or more kinds may be used in combination.

In the resist composition of the present embodiment, the content of the component (B1) is preferably 0.5 to 7 parts by mass, more preferably 1 to 4 parts by mass, and still more preferably 1 to 3 parts by mass, relative to 100 parts by mass of the component (a).

When the content of the component (B1) is in the above range, sufficient patterning can be performed. Further, when the components of the resist composition are dissolved in an organic solvent, a uniform solution is easily obtained, and the storage stability of the resist composition is preferably improved. Further, by setting the content of the component (B1) to be equal to or more than the lower limit of the above-mentioned preferable range, the light transmittance of the resist film can be easily improved, and high sensitivity can be easily achieved.

With respect to the (B2) component

The resist composition of the present embodiment may contain an acid generator component (hereinafter referred to as "component B2") other than the component (B1).

The component (B2) is not particularly limited, and acid generators proposed heretofore as acid generators for use in chemically amplified resist compositions can be used.

Examples of such an acid generator include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators; diazomethane acid generators such as dialkyl or bisarylsulfonyl diazomethane and poly (bissulfonyl) diazomethane; a plurality of acid generators such as nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators and the like.

Examples of the cation portion of component (B2) include organic cations represented by the following general formulae (ca-1) to (ca-5) (except for the structure of the cation portion in general formula (B1-1)).

[ solution 46]

[ in the formula, R²⁰¹～R²⁰⁷And R²¹¹～R²¹²Each independently represents an aryl group, an alkyl group or an alkenyl group which may have a substituent, R²⁰¹～R²⁰³、R²⁰⁶～R²⁰⁷、R²¹¹～R²¹²May be bonded to each other to form a ring together with the sulfur atom in the formula. R²⁰⁸～R²⁰⁹Each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R²¹⁰Is an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or a-SO-containing group which may have a substituent₂-a cyclic radical, L²⁰¹represents-C (═ O) -or-C (═ O) -O-, Y²⁰¹Each independently represents an arylene group, an alkylene group or an alkenylene group, x is 1 or 2, W²⁰¹Represents a (x +1) -valent linking group.]

As R²⁰¹～R²⁰⁷And R²¹¹～R²¹²Examples of the aryl group in (1) include unsubstituted aryl groups having 6 to 20 carbon atoms, and phenyl and naphthyl are preferable.

As R²⁰¹～R²⁰⁷And R²¹¹～R²¹²The alkyl group in (1) is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms.

As R²⁰¹～R²⁰⁷And R²¹¹～R²¹²The alkenyl group in (1) preferably has 2 to 10 carbon atoms.

As R²⁰¹～R²⁰⁷And R²¹⁰～R²¹²Examples of the substituent which may be present include alkyl groups, halogen atoms, haloalkyl groups, carbonyl groups, cyano groups, amino groups, aryl groups, and groups represented by the above formulae (ca-r-1) to (ca-r-8).

At R²⁰¹～R²⁰³、R²⁰⁶～R²⁰⁷、R²¹¹～R²¹²When they are bonded to each other to form a ring together with the sulfur atom in the formula, they may be bonded to each other via a heteroatom such as a sulfur atom, an oxygen atom, a nitrogen atom or the like, a carbonyl group, -SO-, -SO₂-、-SO₃-, -COO-, -CONH-or-N (R)_N) - (the R)_NAlkyl group having 1 to 5 carbon atoms) and the like. The ring to be formed is preferably a three-to ten-membered ring in which 1 ring including the sulfur atom in the formula in the ring skeleton includes a sulfur atom, and particularly preferably a five-to seven-membered ring. Specific examples of the ring to be formed include a thiophene ring, a thiazole ring, a benzothiophene ring, a thianthrene ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thioxanthone ring, a thianthrene ring, a phenoxathiin ring, a tetrahydrothiophenium ring, and a tetrahydrothiopyranium ring.

R²⁰⁸～R²⁰⁹Each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, in R²⁰⁸～R²⁰⁹In the case of an alkyl group, they may be bonded to each other to form a ring.

R²¹⁰Is an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or a-SO-containing group which may have a substituent₂-a cyclic group.

As R²¹⁰The alkyl group in (1) is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms.

As R²¹⁰The alkenyl group in (1) preferably has 2 to 10 carbon atoms.

As R²¹⁰Wherein the-SO-containing group may have a substituent₂Examples of the "cyclic group" may include the groups represented by the general formulae (a5-r-1) to (a5-r-4) containing-SO₂The groups having the same cyclic groups, wherein "containing SO" is preferred₂A polycyclic group ", and more preferably a group represented by the general formula (a 5-r-1).

In the formulae (ca-4) and (ca-5), Y²⁰¹Each independently represents an arylene group, an alkylene group or an alkenylene group.

Y²⁰¹The arylene group in (A) is exemplified by R in said formula (b1-1-an1)¹⁰¹The aromatic hydrocarbon group in (1) is a group obtained by removing 1 hydrogen atom from an aryl group.

Y²⁰¹The alkylene group and alkenylene group in (a) may be exemplified by those represented by R in the formula (b1-1-an1)¹⁰¹The group (b) in (a) is a group obtained by removing 1 hydrogen atom from the group exemplified as the chain alkyl group or the chain alkenyl group.

In the formulas (ca-4) and (ca-5), x is 1 or 2.

W²⁰¹Is a linking group having a valence of (x +1), i.e., 2 or 3.

As W²⁰¹The 2-valent linking group in (a) is preferably a 2-valent hydrocarbon group which may have a substituent(s), and may be exemplified by the group corresponding to Ya in the above-mentioned general formula (a2-1)²¹The same 2-valent hydrocarbon group which may have a substituent. W²⁰¹The 2-valent linking group in (b) may be linear, branched or cyclic, and is preferably cyclic. Among these, a group in which 2 carbonyl groups are combined at both ends of an arylene group is preferable. The arylene group may, for example, be a phenylene group or a naphthylene group, and a phenylene group is particularly preferred.

As W²⁰¹The linking group having a valence of 3 in (1) may, for example, be represented by the formula W²⁰¹Wherein 1 hydrogen atom is removed from the 2-valent linking group, and the 2-valent linking group is bonded to the 2-valent linking groupGroups, and the like. As W²⁰¹The linking group having a valence of 3 in (1) is preferably a group in which 2 carbonyl groups are bonded to an arylene group.

Specific examples of the preferable cation represented by the formula (ca-1) include cations represented by the following formulae (ca-1-1) to (ca-1-101).

[ solution 47]

[ solution 48]

[ solution 49]

[ wherein g1, g2 and g3 represent the number of repeats, g1 is an integer of 1 to 5, g2 is an integer of 0 to 20, and g3 is an integer of 0 to 20. ]

[ solution 50]

[ solution 51]

[ solution 52]

Specific examples of the preferable cation represented by the formula (ca-2) include a diphenyliodonium cation and a bis (4-tert-butylphenyl) iodonium cation.

Specific examples of the preferable cation represented by the formula (ca-3) include cations represented by the following formulae (ca-3-1) to (ca-3-5).

[ Hua 53]

Specific examples of the preferable cation represented by the formula (ca-4) include cations represented by the following formulae (ca-4-1) to (ca-4-2).

[ solution 54]

Further, as the cation represented by the above formula (ca-5), cations represented by the following general formulae (ca-5-1) to (ca-5-3) are also preferable.

[ solution 55]

In the resist composition of the present embodiment, 1 kind of the component (B2) may be used alone, or 2 or more kinds may be used in combination.

When the resist composition contains the component (B2), the content of the component (B2) in the resist composition is preferably 3.5 parts by mass or less, more preferably 0.5 to 2 parts by mass, and still more preferably 0.5 to 1.5 parts by mass, relative to 100 parts by mass of the component (a).

When the content of the component (B2) is in the above range, sufficient patterning can be performed. Further, when the components of the resist composition are dissolved in an organic solvent, a uniform solution is easily obtained, and the storage stability of the resist composition is preferably improved.

Other ingredients

The resist composition of the present embodiment may further contain other components in addition to the above-described component (a) and component (B). Examples of the other components include the following components (D), (E), (F), and (S).

Component (D) for an acid diffusion-controlling agent

The resist composition of the present embodiment may further contain an acid diffusion controller component (hereinafter referred to as "component (D)") in addition to the component (a) or the components (a) and (B). (D) The component (a) is a substance that acts as a quencher (acid diffusion controller) for capturing an acid generated by exposure in the resist composition.

(D) The component (c) may be a photodegradable base (D1) (hereinafter referred to as "component (D1)") which is decomposed by exposure to light and loses its acid diffusion controllability, or a nitrogen-containing organic compound (D2) (hereinafter referred to as "component (D2)") which does not belong to the component (D1).

Component (D1)

When a resist pattern is formed using the resist composition containing the component (D1), the contrast between exposed portions and unexposed portions of the resist film can be improved.

The component (D1) is not particularly limited as long as it is a component which loses acid diffusion controllability by decomposition by exposure to light, and is preferably 1 or more compounds selected from the group consisting of a compound represented by the following general formula (D1-1) (hereinafter referred to as a "D1-1 component"), a compound represented by the following general formula (D1-2) (hereinafter referred to as a "D1-2 component"), and a compound represented by the following general formula (D1-3) (hereinafter referred to as a "D1-3 component").

The components (d1-1) to (d1-3) decompose in the exposed portion of the resist film and lose the acid diffusion controllability (basicity), and thus cannot function as a quencher, but function as a quencher in the unexposed portion.

[ solution 56]

[ in the formula, Rd¹～Rd⁴The alkyl group may be a cyclic group which may have a substituent, a linear alkyl group which may have a substituent, or a linear alkenyl group which may have a substituent. Wherein Rd in the formula (d1-2)²To the carbon atom adjacent to the S atom in (1) is not bonded with a fluorine atom. Yd¹Is a single bond or a 2-valent linking group. m is an integer of 1 or more，M^m+Each independently an m-valent organic cation.]

{ (d1-1) composition }

Anion moiety

In the formula (d1-1), Rd¹Examples of the substituent(s) include a cyclic group which may have a substituent(s), a linear alkyl group which may have a substituent(s), and a linear alkenyl group which may have a substituent(s), and R in the above-mentioned formula (b1-1-an1)¹⁰¹The same groups.

Among these, as Rd¹Preferred is an aromatic hydrocarbon group which may have a substituent, an alicyclic group which may have a substituent, or a chain alkyl group which may have a substituent. Examples of the substituent which these groups may have include a hydroxyl group, an oxo group, an alkyl group, an aryl group, a fluorine atom, a fluoroalkyl group, lactone ring-containing groups represented by the general formulae (a2-r-1) to (a2-r-7), ether bonds, ester bonds, and combinations thereof. In the case where an ether bond or an ester bond is contained as a substituent, an alkylene group may be present, and as the substituent in this case, linking groups represented by the above formulae (y-al-1) to (y-al-5) are preferred.

As the aromatic hydrocarbon group, a phenyl group or a naphthyl group is more preferable.

The alicyclic group is more preferably a group obtained by removing 1 or more hydrogen atoms from a polycyclic alkane such as adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, or the like.

The chain alkyl group is preferably a linear alkyl group having 1 to 10 carbon atoms, and specifically, may, for example, be a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, or the like; branched alkyl groups such as 1-methylethyl, 1-methylpropyl, 2-methylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl and 4-methylpentyl.

When the chain alkyl group is a fluoroalkyl group having a fluorine atom or a fluoroalkyl group as a substituent, the fluoroalkyl group preferably has 1 to 11 carbon atoms, more preferably 1 to 8 carbon atoms, and still more preferably 1 to 4 carbon atoms. The fluoroalkyl group may contain an atom other than a fluorine atom. Examples of the atom other than the fluorine atom include an oxygen atom, a sulfur atom, and a nitrogen atom.

As Rd¹The fluoroalkyl group is preferably a fluoroalkyl group in which a part or all of the hydrogen atoms constituting the linear alkyl group are substituted with fluorine atoms, and particularly preferably a fluoroalkyl group (linear perfluoroalkyl group) in which all of the hydrogen atoms constituting the linear alkyl group are substituted with fluorine atoms.

Preferred specific examples of the anion portion of the component (d1-1) are shown below.

[ solution 57]

Cation part

In the formula (d1-1), M^m+Is an organic cation with a valence of m.

As M^m+The organic cation of (2) may preferably be the same as the cations represented by the general formulae (ca-1) to (ca-5), respectively, or the same as the cation represented by the general formula (ca-1-01), or the cation represented by the general formula (ca-1-02). Among these, the cations represented by the general formula (ca-1) are more preferable, and the cations represented by the formulae (ca-1-1) to (ca-1-101) are still more preferable.

The component (d1-1) may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

{ (d1-2) composition }

Anion moiety

In the formula (d1-2), Rd²Examples of the "cyclic" group which may have a substituent(s), the "linear alkyl" group which may have a substituent(s), and the "linear alkenyl" group which may have a substituent(s) include R in the above-mentioned formula (b1-1-an1)¹⁰¹The same groups.

Wherein, Rd²The carbon atom adjacent to the S atom in (1) is not bonded with a fluorine atom (fluorine-free substitution). Thus, the anion of the component (D1-2) becomes a moderately weak acid anion, and the quenching ability as the component (D) is improved.

AsRd²Preferred is a chain alkyl group which may have a substituent, or an alicyclic group which may have a substituent. The chain alkyl group preferably has 1 to 10 carbon atoms, more preferably 3 to 10 carbon atoms. The alicyclic group is more preferably a group (which may have a substituent) obtained by removing 1 or more hydrogen atoms from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, or the like; groups obtained by removing 1 or more hydrogen atoms from camphor and the like.

Rd²The hydrocarbon group (C) may have a substituent, and examples of the substituent include Rd of the formula (d1-1)¹The hydrocarbon group (aromatic hydrocarbon group, alicyclic group, or chain alkyl group) in (1) may have the same substituent.

Preferred specific examples of the anion portion of the component (d1-2) are shown below.

[ solution 58]

Cation part

In the formula (d1-2), M^m+Is an organic cation having a valence of M, with M in said formula (d1-1)^m+The same is true.

The component (d1-2) may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

{ (d1-3) composition }

Anion moiety

In the formula (d1-3), Rd³Examples of the "cyclic group" which may have a substituent(s), "linear alkyl group which may have a substituent(s)" or "linear alkenyl group which may have a substituent(s)" may include R in the above-mentioned formula (b1-1-an1)¹⁰¹The same group is preferably a cyclic group, a linear alkyl group or a linear alkenyl group containing a fluorine atom. Among them, fluoroalkyl group is preferable, and Rd is more preferable¹The fluoroalkyl group of (a) is the same fluoroalkyl group.

In the formula (d1-3), Rd⁴Examples of the "cyclic" group which may have a substituent(s), the "linear alkyl" group which may have a substituent(s), and the "linear alkenyl" group which may have a substituent(s) include R in the above-mentioned formula (b1-1-an1)¹⁰¹The same group。

Among them, preferred are alkyl groups, alkoxy groups, alkenyl groups, and cyclic groups which may have a substituent.

Rd⁴The alkyl group in (b) is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specifically, it may, for example, be a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group or a neopentyl group. Rd⁴A part of the hydrogen atoms of the alkyl group in (b) may be substituted by a hydroxyl group, a cyano group or the like.

Rd⁴The alkoxy group in (3) is preferably an alkoxy group having 1 to 5 carbon atoms, and specific examples of the alkoxy group having 1 to 5 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group and a tert-butoxy group. Among them, methoxy group and ethoxy group are preferable.

Rd⁴The alkenyl group in (A) is exemplified by the one represented by R in the above-mentioned formula (b1-1-an1)¹⁰¹The same groups are preferably vinyl, propenyl (allyl), 1-methylpropenyl, 2-methylpropenyl. These groups may further have an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms as a substituent.

Rd⁴The cyclic group in (A) is exemplified by the group R in the above formula (b1-1-an1)¹⁰¹The same groups are preferably alicyclic groups obtained by removing 1 or more hydrogen atoms from cycloalkanes such as cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane and tetracyclododecane, or aromatic groups such as phenyl and naphthyl. At Rd⁴In the case of an alicyclic group, the resist composition is favorably dissolved in an organic solvent, whereby the lithographic characteristics are favorable. Furthermore, at Rd⁴In the case of an aromatic group, the resist composition is excellent in light absorption efficiency and excellent in sensitivity and lithographic characteristics.

In the formula (d1-3), Yd¹Is a single bond or a 2-valent linking group.

As Yd¹The 2-valent linking group in (2) is not particularly limited, and examples thereof include a 2-valent hydrocarbon group (aliphatic hydrocarbon group, aromatic hydrocarbon group) having a substituent, a 2-valent linking group containing a heteroatom, and the like. These may be eachExemplified by Ya in relation to the above formula (a2-1)²¹The substituent (2) valent hydrocarbon group which may have a substituent and the heteroatom-containing 2 valent linking group exemplified in the description of the 2 valent linking group in (1).

As Yd¹Preferably a carbonyl group, ester linkage, amide linkage, alkylene group, or a combination thereof. The alkylene group is more preferably a linear or branched alkylene group, and still more preferably a methylene group or an ethylene group.

Preferred specific examples of the anion portion of the component (d1-3) are shown below.

[ chemical 59]

[ solution 60]

Cation part

In the formula (d1-3), M^m+Is an organic cation having a valence of M, with M in said formula (d1-1)^m+The same is true.

The component (d1-3) may be used alone in 1 kind or in combination of 2 or more kinds.

(D1) Component (c) may be any of the above-mentioned components (d1-1) to (d1-3), or 2 or more of them may be used in combination.

When the resist composition contains the component (D1), the content of the component (D1) is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, and still more preferably 1 to 8 parts by mass, based on 100 parts by mass of the component (a).

When the content of the (D1) component is equal to or greater than the preferable lower limit, particularly good lithographic characteristics and resist pattern shape can be easily obtained. On the other hand, if the value is not more than the upper limit, the sensitivity can be maintained well, and the yield (throughput) is also excellent.

(D1) The method for producing the component (A):

the method for producing the component (d1-1) or the component (d1-2) is not particularly limited, and the component (d1-1) or the component (d1-2) can be produced by a known method.

The method for producing the component (d1-3) is not particularly limited, and the component (d1-3) can be produced, for example, in the same manner as the method described in U.S. Pat. No. 2012-0149916.

With respect to the (D2) component

The acid diffusion-controlling agent component may contain a nitrogen-containing organic compound component (hereinafter referred to as the "component D2") other than the above-mentioned component D1.

The component (D2) is not particularly limited as long as it functions as an acid diffusion controller and does not belong to the component (D1), and any known component may be used. Among them, aliphatic amines are preferable, and among them, secondary aliphatic amines and tertiary aliphatic amines are particularly more preferable.

The aliphatic amine is an amine having 1 or more aliphatic groups, and the aliphatic group preferably has 1 to 12 carbon atoms.

The aliphatic amine may, for example, be ammonia NH₃An amine (alkylamine or alkylol amine) or a cyclic amine obtained by substituting at least 1 of the hydrogen atoms of (a) with an alkyl group or a hydroxyalkyl group having 12 or less carbon atoms.

Specific examples of the alkylamine and the alkylol amine include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; dialkylamines such as diethylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, and dicyclohexylamine; trialkylamines such as trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, and tri-n-dodecylamine; and alkylolamines such as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine and tri-n-octanolamine. Among these, trialkylamines having 5 to 10 carbon atoms are more preferable, and tri-n-pentylamine or tri-n-octylamine is particularly preferable.

Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be a monocyclic compound (aliphatic monocyclic amine) or a polycyclic compound (aliphatic polycyclic amine).

Specific examples of the alicyclic monocyclic amine include piperidine and piperazine.

The aliphatic polycyclic amine is preferably one having 6 to 10 carbon atoms, and specifically, it may, for example, be 1, 5-diazabicyclo [4.3.0] -5-nonene, 1, 8-diazabicyclo [5.4.0] -7-undecene, hexamethylenetetramine or 1, 4-diazabicyclo [2.2.2] octane.

Examples of the other aliphatic amine include tris (2-methoxymethoxyethyl) amine, tris {2- (2-methoxyethoxy) ethyl } amine, tris {2- (2-methoxyethoxymethoxy) ethyl } amine, tris {2- (1-methoxyethoxy) ethyl } amine, tris {2- (1-ethoxyethoxy) ethyl } amine, tris {2- (1-ethoxypropoxy) ethyl } amine, tris [2- {2- (2-hydroxyethoxy) ethoxy } ethyl ] amine, and triethanolamine triacetate is preferable.

As the component (D2), an aromatic amine can be used.

Examples of the aromatic amine include 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, tribenzylamine, 2, 6-diisopropylaniline, and n-tert-butoxycarbonylpyrrolidine.

(D2) The components may be used alone or in combination of 2 or more.

When the resist composition contains the component (D2), the component (D2) is usually used in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the component (a). By setting the above range, the resist pattern shape, the stability with time of standing, and the like are improved.

A compound (E) containing at least 1 member selected from the group consisting of organic carboxylic acids and phosphorus oxo acids and derivatives thereof

The resist composition of the present embodiment may contain at least 1 compound (E) (hereinafter referred to as "component (E)") selected from the group consisting of organic carboxylic acids, phosphorus oxyacids and derivatives thereof as an optional component for the purpose of preventing sensitivity deterioration, improving resist pattern shape, stability with standing, and the like.

As the organic carboxylic acid, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid, and the like are preferable.

The oxyacid of phosphorus may, for example, be phosphoric acid, phosphonic acid or phosphinic acid, and among these, phosphonic acid is particularly preferred.

Examples of the derivative of an oxyacid of phosphorus include esters obtained by substituting a hydrogen atom of the oxyacid with a hydrocarbon group, and examples of the hydrocarbon group include an alkyl group having 1 to 5 carbon atoms and an aryl group having 6 to 15 carbon atoms.

Examples of the phosphoric acid derivative include phosphoric acid esters such as di-n-butyl phosphate and diphenyl phosphate.

Examples of the phosphonic acid derivative include phosphonic acid esters such as dimethyl phosphonate, di-n-butyl phosphonate, phenylphosphonic acid, diphenyl phosphonate, and dibenzyl phosphonate.

The phosphinic acid derivative may, for example, be a phosphinic acid ester or phenylphosphinic acid.

(E) The components can be used alone in 1 kind, or can be used in combination in more than 2 kinds.

When the resist composition contains the component (E), the component (E) is usually used in an amount of 0.01 to 5 parts by mass based on 100 parts by mass of the component (a).

With respect to the fluorine additive component (F)

The resist composition of the present embodiment may contain a fluorine additive component (hereinafter referred to as "component (F)") in order to impart water repellency to the resist film.

As the component (F), for example, fluorine-containing polymer compounds described in Japanese patent application laid-open Nos. 2010-002870, 2010-032994, 2010-277043, 2011-13569 and 2011-128226 can be used.

More specifically, the component (F) may be a polymer having a structural unit (F1) represented by the following formula (F1-1). As the polymer, a polymer (homopolymer) composed only of a structural unit (f1) represented by the following formula (f1-1) is preferable; a copolymer of the structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid and the structural unit (f 1); the structural unit (f1), a structural unit derived from acrylic acid or methacrylic acid, and a copolymer of the structural unit (a 1). Examples of the preferable structural unit of the structural unit (a1) copolymerized with the structural unit (f1) include a structural unit derived from 1-ethyl-1-cyclooctyl (meth) acrylate and a structural unit derived from 1-methyl-1-adamantyl (meth) acrylate.

[ solution 61]

[ wherein R is the same as defined above, Rf¹⁰²And Rf¹⁰³Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms, Rf¹⁰²And Rf¹⁰³May be the same or different. nf¹Is an integer of 1 to 5, Rf¹⁰¹Is an organic group containing a fluorine atom.]

In the formula (f1-1), R bonded to the carbon atom at the α -position is the same as described above. As R, a hydrogen atom or a methyl group is preferable.

In the formula (f1-1), as Rf¹⁰²And Rf¹⁰³Examples of the halogen atom of (b) include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is particularly preferable. As Rf¹⁰²And Rf¹⁰³Examples of the alkyl group having 1 to 5 carbon atoms include the same ones as those mentioned for the alkyl group having 1 to 5 carbon atoms for R, and a methyl group or an ethyl group is preferable. As Rf¹⁰²And Rf¹⁰³The haloalkyl group having 1 to 5 carbon atoms in (b) may specifically be a group in which a part or all of hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with a halogen atom.

The halogen atom may, for example, be a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and a fluorine atom is particularly preferable. Wherein as Rf¹⁰²And Rf¹⁰³The alkyl group is preferably a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms, and is preferably a hydrogen atom, a fluorine atom, a methyl group or an ethyl group.

In the formula (f1-1), nf¹Is an integer of 1 to 5, preferably an integer of 1 to 3, more preferably 1 or 2.

In the formula (f1-1), Rf¹⁰¹Is an organic group containing a fluorine atom, preferably a hydrocarbon group containing a fluorine atom.

The hydrocarbon group containing a fluorine atom may be any of a straight chain, a branched chain and a cyclic group, and the number of carbon atoms is preferably 1 to 20, more preferably 1 to 15, and particularly preferably 1 to 10.

The hydrocarbon group containing a fluorine atom is preferably fluorinated in an amount of 25% or more, more preferably 50% or more, of the hydrogen atoms in the hydrocarbon group, and is particularly preferably fluorinated in an amount of 60% or more, since the hydrophobicity of the resist film at the time of immersion exposure is improved.

Wherein, as Rf¹⁰¹More preferred is a C1-6 fluorinated hydrocarbon group, and particularly preferred is a trifluoromethyl group, -CH₂-CF₃、-CH₂-CF₂-CF₃、-CH(CF₃)₂、-CH₂-CH₂-CF₃、-CH₂-CH₂-CF₂-CF₂-CF₂-CF₃。

(F) The weight average molecular weight (Mw) of the component (A) is preferably 1000 to 50000, more preferably 5000 to 40000, most preferably 10000 to 30000 (in terms of polystyrene equivalent by gel permeation chromatography). If the lower limit of the range is less than the upper limit, the solvent for a resist has sufficient solubility when used as a resist, and if the lower limit of the range is more than the lower limit, the dry etching resistance and the cross-sectional shape of a resist pattern are good.

(F) The molecular weight distribution coefficient (Mw/Mn) of the component (B) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5.

(F) The components can be used alone in 1 kind, or can be used in combination in more than 2 kinds.

When the resist composition contains the component (F), the component (F) is usually used in a proportion of 0.5 to 10 parts by mass relative to 100 parts by mass of the component (A).

Regarding the organic solvent component (S)

The resist composition of the present embodiment can be produced by dissolving a resist material in an organic solvent component (hereinafter, sometimes referred to as "S component").

The component (S) is not particularly limited as long as it can dissolve each component used to form a uniform solution, and any component may be appropriately selected from those conventionally known as solvents for chemically amplified resist compositions.

For example, the component (S) may include lactones such as γ -butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-amyl ketone, methyl isoamyl ketone, and 2-heptanone; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; derivatives of polyhydric alcohols such as compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, or dipropylene glycol monoacetate, and compounds having an ether bond such as monomethyl ethers, monoethyl ethers, monopropyl ethers, monobutyl ethers, and the like of the polyhydric alcohols or the compounds having an ester bond [ among these, Propylene Glycol Monomethyl Ether Acetate (PGMEA), Propylene Glycol Monomethyl Ether (PGME) ]; esters such as cyclic ethers like dioxane, methyl lactate, Ethyl Lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; aromatic organic solvents such as anisole, ethylbenzyl ether, methyltolyl ether, diphenyl ether, dibenzyl ether, phenetole, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, isopropyltoluene, mesitylene, and the like; dimethylsulfoxide (DMSO), and the like.

The component (S) may be used alone or as a mixed solvent of 2 or more.

Among them, PGMEA, PGME, gamma-butyrolactone, EL, and cyclohexanone are preferable.

In addition, a mixed solvent obtained by mixing PGMEA with a polar solvent is also preferable. The blending ratio (mass ratio) thereof may be appropriately determined in consideration of the compatibility of PGMEA with a polar solvent, and the like, and is preferably 1: 9-9: 1, more preferably 2: 8-8: 2, or a salt thereof.

More specifically, in the case of blending EL or cyclohexanone as a polar solvent, PGMEA: the mass ratio of EL or cyclohexanone is preferably 1: 9-9: 1, more preferably 2: 8-8: 2. further, in the case of blending PGME as a polar solvent, PGMEA: the mass ratio of PGME is preferably 1: 9-9: 1, more preferably 2: 8-8: 2, more preferably 3: 7-7: 3. in addition, a mixed solvent of PGMEA and PGME with cyclohexanone is also preferable.

In addition to the (S) component, a mixed solvent of γ -butyrolactone and at least 1 selected from PGMEA and EL is also preferable. In this case, the mixing ratio of the former to the latter is preferably 70: 30-95: 5.

the amount of the component (S) used is not particularly limited, and is appropriately set according to the coating film thickness at a concentration at which the component (S) can be applied to a substrate or the like. Generally, the (S) component is used so that the solid content concentration of the resist composition is in the range of 20 to 55 mass%, preferably 30 to 45 mass%.

The resist composition of the present embodiment may further contain additives having miscibility, for example, an additional resin for improving the performance of the resist film, a surfactant (for example, a fluorine-based surfactant), a dissolution inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent, a dye, and the like, as desired.

The resist pattern forming method of the present embodiment described above is a method useful for forming a resist film having a high film thickness of 7 μm or more, and is carried out using a specific resist composition.

By using a specific resist composition, that is, a resist composition containing a monophenyl acid generator (component B1) composed of a compound represented by the general formula (B1-1), the light transmittance of a resist film having a high film thickness can be improved. Therefore, even when a resist film having a high film thickness of 7 μm or more is formed, it is possible to form a resist pattern having a good shape while achieving high sensitivity and improving resolution.

In addition, according to the above-described resist pattern forming method, since the light transmittance of the resist film can be improved by using the specific resist composition, even for resist films having different film thicknesses on wafers having a level difference, the pattern can be formed while suppressing the dimensional variation to a small extent.

Further, according to the above resist pattern forming method, dimensional variation can be suppressed even in a standing state after exposure.

The above-described resist pattern forming method is useful for manufacturing a three-dimensional structure device, and is a preferable method for use in processing a multi-stage stepped structure (such as superposition). By applying the resist pattern forming method of this embodiment mode, lamination of memory films can be realized with high accuracy (manufacturing of a three-dimensional, large-capacity memory).