阅读说明：本技术 抗蚀剂组合物以及抗蚀剂图案形成方法 (Resist composition and resist pattern forming method ) 是由 大野庆晃 河野绅一 于 2019-06-28 设计创作，主要内容包括：本发明提供一种抗蚀剂组合物,特别是在将厚膜的抗蚀剂膜成膜而形成抗蚀剂图案的情况下,光刻特性优异且涂布性良好,能够抑制在高温烘烤时来自抗蚀剂图案的发泡。本发明的抗蚀剂组合物,含有：高分子化合物,具有以式(a10-1)表示的结构单元以及包含酸分解性基团的结构单元；以式(b1)表示的产酸剂,抗蚀剂组合物中的固体成分浓度为30质量％以上。式(a10-1)中,R为氢原子、烷基或卤代烷基,Ya<Sup>x1</Sup>为单键或2价连接基团,Wa<Sup>x1</Sup>为芳香族烃基,n<Sub>ax1</Sub>是1～3的整数,式(b)中,R<Sup>2011</Sup>、R<Sup>2021</Sup>以及R<Sup>2031</Sup>分别独立地表示芳基,2个以上也可以相互键合而与式中的硫原子一起形成环,X<Sup>-</Sup>表示反荷阴离子。<Image he="296" wi="700" file="DDA0002111511360000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>(The invention provides a resist composition, which has excellent lithographic characteristics and good coating properties, and can inhibit foaming from a resist pattern during high-temperature baking, particularly when a thick resist film is formed to form a resist pattern. The resist composition of the present invention comprises: a polymer compound having a structural unit represented by formula (a10-1) and a structural unit containing an acid-decomposable group; the acid generator represented by the formula (b1) has a solid content concentration in the resist composition of 30% by mass or more. In the formula (a10-1), R is a hydrogen atom, an alkyl group or a haloalkyl group，Ya x1 Is a single bond or a 2-valent linking group, Wa x1 Is an aromatic hydrocarbon radical, n ax1 Is an integer of 1 to 3, wherein R in the formula (b) 2011 、R 2021 And R 2031 Each independently represents an aryl group, 2 or more of which may be bonded to each other to form a ring together with the sulfur atom in the formula, X ‑ Denotes a counter anion.)

1. A resist composition which generates an acid upon exposure and whose solubility in a developer changes by the action of the acid, characterized by comprising:

a polymer compound (A1) having a structural unit (a10) represented by the following general formula (a10-1) and a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid; an acid generator (B1) represented by the following general formula (B1),

the solid content concentration in the resist composition is 30 mass% or more;

[ CHEM 1]

Wherein R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a haloalkyl 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 group; n is_ax1Is an integer of 1 to 3; r²⁰¹¹、R²⁰²¹And R²⁰³¹Each independently represents an aryl group which may have a substituent; r²⁰¹¹、R²⁰²¹And R²⁰³¹2 or more of them may be bonded to each other to form a ring together with the sulfur atom in the formula; x^-Denotes a counter anion.

2. The resist composition of claim 1,

r in the general formula (b1)²⁰¹¹、R²⁰²¹And R²⁰³¹At least 1 of which is an aryl group having a substituent,

the substituent is 1 or more selected from the group consisting of alkyl group, halogen atom, haloalkyl group, carbonyl group, cyano group, amino group, aryl group, and groups represented by the following general formulae (ca-r-1) to (ca-r-7);

[ CHEM 2]

In the formula (II), 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.

3. The resist composition according to claim 1 or 2, wherein the concentration of the polymer compound (a1) in the entire solid content of the resist composition is 90% by mass or more.

4. The resist composition according to any one of claims 1 to 3, wherein the high molecular compound (A1) has a weight average molecular weight of 5000 to 20000.

5. A method for forming a resist pattern, comprising:

a step (i) of forming a resist film on a support by using the resist composition according to any one of claims 1 to 4;

a step (ii) of exposing the resist film;

and (iii) developing the exposed resist film to form a resist pattern.

6. The method of forming a resist pattern according to claim 5, wherein in the step (ii), the resist film is irradiated with KrF excimer laser light.

Technical Field

The invention relates to a resist composition and a resist pattern forming method.

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, the miniaturization of patterns has been rapidly advanced due to the progress of photolithography. As a method for miniaturization, generally, the exposure light source is shortened in wavelength (increased in energy). Specifically, although ultraviolet rays typified by g-rays and i-rays have been used conventionally, semiconductor devices are now mass-produced using KrF excimer laser light or ArF excimer laser light. 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 of 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 to 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 base resin of a chemically amplified resist composition, for example, Polyhydroxystyrene (PHS) having high transparency to KrF excimer laser light (248nm), a resin (PHS-based resin) in which a hydroxyl group thereof is protected by an acid-dissociable dissolution-inhibiting group, or 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 has been 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.

In recent years, the photoelectric processing has become a mainstream of the precision microfabrication technology. The photolithography processing is a processing technique for producing various precision parts by applying the chemically amplified resist composition to the surface of a workpiece to form a resist film, forming a resist pattern having a predetermined shape on the resist film, and performing chemical etching, electrolytic etching, electroforming mainly using electroplating, or the like using the resist pattern as a mask.

In the above-mentioned photoelectric processing, depending on the application, a thick resist film having a film thickness of, for example, 8 μm or more is formed on the surface of the object, and a resist pattern is formed and etched.

Disclosure of Invention

Technical problem to be solved by the invention

When a thick resist film is formed using a chemically amplified resist composition, it is more difficult to apply the chemically amplified resist composition to a workpiece in a uniform thickness as the resist film becomes thicker. In addition, the formed resist pattern has a problem that lithographic characteristics (e.g., dimensional uniformity) are likely to be deteriorated.

In addition, when a resist pattern is formed using a chemically amplified resist composition, the thicker the resist film, the more difficult it is to maintain the sensitivity at the time of exposure. In contrast, for example, by using a chemically amplified resist composition in which an iodonium salt is selected as an acid generator component, sensitivity can be improved.

However, in the studies of the present inventors, it was confirmed that, when a chemically amplified resist composition containing an iodonium salt is used, foaming occurs when the support on which the resist film is formed is baked at a high temperature (180 ℃ or higher) (for example, when baking treatment (post-baking) is performed after development treatment or after rinsing treatment). In the resist composition which is likely to cause foaming in this manner, there is a problem that the effect of removing the residue is insufficient in ashing treatment for rework, for example.

The present invention has been made in view of the above circumstances, and has a technical problem in that: provided are a resist composition which has excellent lithographic characteristics and good coatability and which can suppress foaming from a resist pattern during high-temperature baking in the formation of a resist pattern, particularly in the formation of a resist pattern by forming a thick resist film, and a method for forming a resist pattern using the same.

Solution for solving the above technical problem

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

That is, the invention according to claim 1 is a resist composition which generates an acid upon exposure and whose solubility in a developer is changed by the action of the acid, comprising: a polymer compound (A1) having a structural unit (a10) represented by the following general formula (a10-1) and a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid; and an acid generator (B1) represented by the following general formula (B1), wherein the concentration of the solid component in the resist composition is 30% by mass or more.

[ CHEM 1]

[ wherein R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a haloalkyl 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, R²⁰¹¹、R²⁰²¹And R²⁰³¹Each independently represents an aryl group which may have a substituent. R²⁰¹¹、R²⁰²¹And R²⁰³¹2 or more of them may be bonded to each other to form a ring together with the sulfur atom in the formula. X^-Denotes a counter anion.]

The invention according to claim 2 is a resist pattern forming method including: a step (i) of forming a resist film on a support using the resist composition according to claim 1; a step (ii) of exposing the resist film; and (iii) developing the exposed resist film to form a resist pattern.

Effects of the invention

According to the present invention, it is possible to provide a resist composition which is excellent in lithographic characteristics and coatability and can suppress foaming from a resist pattern at the time of high-temperature baking in the formation of a resist pattern, particularly in the case of forming a resist pattern by forming a thick resist film, and a method for forming a resist pattern using the same.

The resist composition and the resist pattern forming method of the present invention are particularly suitable for forming a resist pattern of a thick film.

Detailed Description

In the present specification and the claims, "aliphatic" is a relative concept with respect to aromatic, and is defined to mean groups, compounds, and the like that do not have aromatic properties.

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).

When "may have a substituent" is described, 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 substituted are included₂-) two cases substituted with a 2-valent group.

"exposure" refers to a concept including irradiation of all radiation.

The "(meth) acrylate" refers to one or both of an acrylate having a hydrogen atom bonded to the α -position and a methacrylate having a methyl group bonded to the α -position.

The "(meth) acrylate" refers to one or both of an acrylate having a hydrogen atom bonded to the α -position and a methacrylate having a methyl group bonded to the α -position.

The term "(meth) acrylic acid" refers to one or both of acrylic acid having a hydrogen atom bonded to the α -position and methacrylic acid having a methyl group bonded to the α -position.

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 which a hydrogen atom at the carboxyl terminal is substituted with an organic group.

The hydrogen atom bonded to the carbon atom in the α -position of the acrylate may be substituted with a substituent. A substituent (R) for substituting the hydrogen atom bonded to the carbon atom at the alpha position^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) An alpha hydroxy acrylate substituted with a hydroxyalkyl group or a group modifying the hydroxyl group thereof. Unless otherwise specified, the carbon atom at the α -position of the acrylate refers to a carbon atom to which a carbonyl group of acrylic acid is bonded.

Hereinafter, an acrylate in which a hydrogen atom bonded to an α -position carbon atom is substituted with a substituent may be referred to as an α -substituted acrylate. Further, the acrylate and the α -substituted acrylate are also collectively referred to as "(α -substituted) acrylate".

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 obtained by substituting a substituent for a hydrogen atom bonded to a carbon atom in the α -position, or by substituting a substituent for one or both of hydrogen atoms of an amino group of the acrylamide. 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 substituting the hydrogen atom bonded to the carbon atom at the α -position of acrylamide include the groups (substituents (R) listed as the α -position substituents in the above-mentioned α -substituted acrylic acid ester^α0) ) the same radicalAnd (4) clustering.

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 in which an olefinic double bond of the hydroxystyrene derivative is cleaved.

The term "hydroxystyrene derivative" is intended to include 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 include compounds in which the hydrogen atom at the α -position is substituted with a substituent, and the hydrogen atom of the 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) of hydroxystyrene 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 include the same groups as those listed as the substituent at the α -position in the above 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 intended to include compounds in which the hydrogen atom at the α -position of vinylbenzoic acid is substituted with other substituent such as alkyl group, haloalkyl group and the like, and their derivatives. Examples of the derivatives include compounds in which the hydrogen atom at the α -position is substituted with a substituent and the hydrogen atom of the carboxyl group of vinylbenzoic acid is substituted with an organic group; and a compound in which a hydrogen atom at the α -position is optionally substituted with a substituent, and a substituent other than a hydroxyl group and a carboxyl group is bonded to the benzene ring of vinylbenzoic acid. In addition, the α -position (carbon atom at α -position) of vinylbenzoic acid means a carbon atom to which a benzene ring is bonded unless otherwise specified.

"styrene" includes styrene and compounds in which the hydrogen atom alpha to styrene is substituted with other substituents such as alkyl and haloalkyl.

The term "styrene derivative" is intended to include compounds in which the hydrogen atom at the α -position of styrene is substituted with other substituents such as alkyl groups and haloalkyl groups, and derivatives thereof. Examples of the derivatives include compounds in which a substituent 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.

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.

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

Specific examples of the hydroxyalkyl group as the substituent at the α -position include those 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, most preferably 1.

In the present description and in the claims, depending on the structure shown in the formula, asymmetric carbons exist and the structure of enantiomers (enantiomers) or diastereomers (diastereomers) may exist. In this case, these isomers are representatively shown in a chemical formula. These isomers may be used alone or as a mixture.

(resist composition)

The invention of claim 1 is the exposure to generate acid and the developer solubility due to acid changes of resist composition.

As an embodiment of the resist composition, there is exemplified a resist composition containing a base component (a) (hereinafter also referred to as "component a"), an acid generator component (B) (hereinafter also referred to as "component B"), and an organic solvent component (S) (hereinafter also referred to as "component S"), wherein the solubility of the base component (a) in a developer changes due to the action of an acid, and the acid generator component (B) generates an acid upon exposure. In the resist composition of the present embodiment, the component (a) contains a specific polymer compound (a1), the component (B) contains a specific acid generator (B1), and the solid content concentration in the resist composition is 30% by mass or more.

The resist composition of the present embodiment is suitable for resist pattern formation by exposure using a KrF excimer laser beam.

The resist composition of the present embodiment is suitable for forming a resist film of, for example, 1 to 10 μm on a support, and is particularly suitable for forming a resist pattern for forming a thick resist film. The thick film referred to herein is a film having a thickness of 6 μm or more. The resist composition of the present embodiment preferably has a thickness of 6 μm or more, and a resist film having a thickness of 7 μm or more, and further 8 μm or more is preferably formed in this range.

When a resist film is formed using the resist composition of the present embodiment and the resist film is selectively exposed, acid is generated from the component (B) in the 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 the 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 is applicable to an alkaline development process using an alkaline developer in a development process in forming a resist pattern, and also applicable to a solvent development process using a developer containing an organic solvent (organic developer) in the development process.

The resist composition of the present embodiment has an acid generating ability to generate an acid upon exposure, and the component (a) may generate an acid upon exposure in addition to the component (B).

When the component (a) generates an acid by exposure, the component (a) is a "base component which generates an acid by exposure and whose solubility in a developer is changed by the action of an acid". (A) When the component (a) is a base component which generates an acid upon exposure and changes its solubility in a developer by the action of the acid, it is preferable that the component (a1) described later is a polymer compound which generates an acid upon exposure and changes its solubility in a developer by the action of the acid. Examples of such a polymer compound include resins having a structural unit that generates an acid upon exposure to light. As the monomer for deriving the structural unit which generates an acid by exposure, a known monomer can be used.

< ingredient (A) >

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

In the present invention, the "base material component" is an organic compound having a 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.

As the component (a) used in the resist composition of the present embodiment, at least the component (a1) is used, and other high molecular compounds and/or low molecular compounds may be used in combination with the component (a 1).

In the resist composition of the present embodiment, the component (a) is a specific polymer compound (a1), namely, a polymer compound (a1) having a structural unit (a10) represented by the general formula (a10-1) described later and a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid (hereinafter also referred to as a "component (a 1)").

When a resist film formed using a resist composition containing the component (a1) is exposed to light, the bonding of at least a part of the structure of the structural unit (a1) is cleaved by the action of an acid, and the polarity is increased. Therefore, the resist composition of the present embodiment is a negative type in the case where the developer is an organic developer (solvent development process), and is a positive type in the case where the developer is an alkaline developer (alkaline development process). Since the polarity of the (a1) 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 by using the (a1) component.

That is, when the 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 of the acid 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 poorly soluble to soluble, while the unexposed portion of the resist film remains poorly soluble and does not change, and thus a positive resist pattern is 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 becomes high by the action of the acid, and the solubility in the organic developer is reduced. 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 changes from soluble to poorly soluble, while the unexposed portion of the resist film remains soluble and does not change, so that by developing with an organic developer, a contrast can be obtained between the exposed portion and the unexposed portion, and a negative resist pattern can be formed.

With respect to the (A1) component

(A1) Component (b) is a polymer compound having a structural unit (a10) represented by the general formula (a10-1) and a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid.

Structural unit (a10)

The structural unit (a10) is a structural unit represented by the following general formula (a 10-1).

[ CHEM 2]

[ wherein R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms. Ya^X1Is a single bond or a 2-valent linking group. Wa^X1Is (n)_ax1Aryl of +1) valencyAn aromatic hydrocarbon group. n is_ax1Is an integer of 1 to 3.]

In the formula (a10-1), R is hydrogen atom, alkyl group with 1-5 carbon atoms or halogenated alkyl group with 1-5 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 is preferably 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, a neopentyl group, or the like. 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. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., 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 a hydrogen atom or a methyl group is most preferable 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) includes, for example, a 2-valent hydrocarbon group which may have a substituent, and 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 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 is preferably a saturated aliphatic hydrocarbon group.

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

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, 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, a methylene group [ -CH ] may be mentioned₂-]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 3 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 specific examples thereof include-CH (CH)₃)-、-CH(CH₂CH₃)-、-C(CH₃)₂-、-C(CH₃)(CH₂CH₃)-、-C(CH₃)(CH₂CH₂CH₃)-、-C(CH₂CH₃)₂-and the like alkylmethylene; -CH (CH)₃)CH₂-、-CH(CH₃)CH(CH₃)-、-C(CH₃)₂CH₂-、-CH(CH₂CH₃)CH₂-、-C(CH₂CH₃)₂-CH₂-and the like, an alkyl ethylene group; -CH (CH)₃)CH₂CH₂-、-CH₂CH(CH₃)CH₂-and the like, alkyl propylene; -CH (CH)₃)CH₂CH₂CH₂-、-CH₂CH(CH₃)CH₂CH₂An alkylalkylene group such as an alkylbutylene group. The alkyl group in the alkyl alkylene group is preferably a linear 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 5 or more carbon atoms and being substituted with a fluorine atom, and a carbonyl group.

Aliphatic hydrocarbon groups containing rings in the structure

Examples of the 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) having a hetero atom in the ring structure and optionally having a substituent, a group obtained by bonding the cyclic aliphatic hydrocarbon group 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 include the same aliphatic hydrocarbon groups as described above.

The number of carbon atoms of the cyclic aliphatic hydrocarbon group is preferably 3 to 20, more preferably 3 to 12.

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 include groups in which a part or all of hydrogen atoms of the alkyl group are substituted with the halogen atom.

Of cyclic aliphatic hydrocarbon groups constituting the ring structure thereofA part of the carbon atoms of (a) may also be substituted with a heteroatom-containing substituent. The heteroatom-containing substituent is preferably-O-, -C (═ O) -O-, -S-, -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 heterocyclic ring 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 the 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 number of carbon atoms of the alkylene group bonded to the aryl or heteroaryl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

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 more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.

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

Heteroatom-containing 2-valent linking groups:

at Ya^x1In the case of a 2-valent linking group containing a hetero atom, preferable 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 a 2-valent hydrocarbon group which may have a substituent, O is an oxygen atom, and m' is 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 be the one mentioned in the description of the 2-valent linking group (which may have a substituent)The 2-valent hydrocarbon group) 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 Ya^x1Preferably a single bond, an ester bond [ -C (═ O) -O-]An ether bond (-O-) -, -C (-O) -NH linear or branched alkylene group, or a combination thereof, and among them, a single bond is more preferable.

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

As Wa^x1The aromatic hydrocarbon group in (1) includes those removed from aromatic ring (n)_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 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. As the aromatic ringSpecific examples thereof 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 heterocyclic ring 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 above formula (a10-1) are shown below.

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

[ CHEM 3 ]

(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 10-1-1).

[ CHEM 4 ]

[ 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 10 to 95 mol%, more preferably 30 to 90 mol%, and particularly preferably 50 to 85 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 (a10) to be equal to or higher than the lower limit of the above-described preferable range, it is easy to further improve the developing property, the lithographic property such as the EL limit (Margin), and the like, and by setting the ratio of the structural unit (a10) to be equal to or lower than the upper limit of the above-described preferable range, it is easy to balance with other structural units.

Structural unit (a1)

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 includes a group in which the polar group is protected by an acid-dissociable group (for example, a group in which a hydrogen atom of an OH-containing polar group is protected by 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 a 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 changes relatively due to the increase in polarity, and the solubility increases when the developer is an alkaline developer and decreases 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 resists.

Specific examples of the group proposed as the acid-dissociable group of the base resin for a chemically amplified resist include "acetal acid-dissociable group", "tert-alkyl ester acid-dissociable group", and "tert-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").

[ CHEM 5 ]

[ 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 the α -position in the above description of the α -substituted acrylate, and is preferably an alkyl group having 1 to 5 carbon atoms. Specifically, a linear or branched alkyl group can be preferably mentioned. More specifically, there may be mentioned methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl and the like, more preferably methyl or ethyl,methyl is particularly preferred.

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. Specific examples thereof include methyl group, ethyl group, n-propyl group, n-butyl group, and n-pentyl group. Among these, 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. Specific examples thereof include isopropyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group, 1-diethylpropyl group, and 2, 2-dimethylbutyl group, with isopropyl group being preferred.

In Ra'³When the hydrocarbon group is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, or may be 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 monocyclic hydrocarbon is preferably a monocyclic hydrocarbon 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 includes adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like.

When the cyclic hydrocarbon group of Ra' 3 is an aromatic hydrocarbon group, the aromatic hydrocarbon group has 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 heterocyclic ring include a pyridine ring and a thiophene ring.

As Ra'³Specific examples of the aromatic hydrocarbon group in (1) include a group (aryl group or heteroaryl group) 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.

Ra’³And Ra'¹、Ra’²In the case where any one of these groups is bonded to form a ring, the cyclic group is preferably a four-to seven-membered ring, and 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 general formula (a1-r-2) will be referred to as a "tertiary alkyl ester-type acid-dissociable group" hereinafter.

[ CHEM 6 ]

[ 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 hydrocarbon group of (2) may be represented by the above Ra'³The same hydrocarbon group.

Ra’⁴Preferably an alkyl group having 1 to 5 carbon atoms. In Ra'⁵And Ra'⁶When they are bonded to each other to form a ring, a group represented by the following general formula (a1-r2-1) may be mentioned. On the other hand, in Ra'⁴～Ra’⁶When the hydrocarbon groups are independent of each other, preferred examples thereof include groups represented by the following general formula (a1-r 2-2).

[ CHEM 7 ]

[ wherein, Ra'¹⁰Represents an alkyl group having 1 to 10 carbon atoms. Ra'¹¹Is represented by and Ra'¹⁰The bonded carbon atoms together form the radical of an alicyclic 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 linear or branched alkyl group of (1) are listed below. 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 alicyclic hydrocarbon group of (1) monocyclic group or polycyclic group is exemplified.

In the formula (a1-r2-2), Ra'¹²And Ra'¹⁴Each independently is 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'¹³More preferably as Ra'³Examples of the hydrocarbon group of (1) include linear or branched alkyl groups.

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

[ CHEM 8 ]

[ CHEM 9 ]

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

[ CHEM 10 ]

Tertiary alkoxycarbonyl acid-dissociable group:

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

[ CHEM 11 ]

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

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

The total number of carbon atoms 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-dissociable group as the base resin for a chemically amplified resist is preferably a tertiary alkyl ester type acid-dissociable group, more preferably an acid-dissociable group represented by the formula (a1-r-2), and still more preferably a group represented by the general formula (a1-r2-2), from the viewpoint of easily obtaining the effect of combining with the component (B) (resolution, dimensional uniformity (CDU) in the surface of the support (Shot), etc.).

Among the groups represented by the general formula (a1-r2-2), preferred are groups represented by the above formula (r-pr-c1), formula (r-pr-c2) or formula (r-pr-c 3).

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

Among the above, as the structural unit (a1), 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.

Preferable specific examples of the structural unit (a1) include structural units represented by the following general formula (a1-1) or (a 1-2).

[ CHEM 12 ]

[ wherein R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a haloalkyl group having 1 to 5 carbon atoms. Va (Va)¹Is a 2-valent hydrocarbon group which may have an ether bond, n_a1Is an integer of 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 includes methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl and the like. The C1-5 haloalkyl is a group in which a part or all of the hydrogen atoms of the C1-5 alkyl are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., 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), Va¹With a 2-valent hydrocarbon group which may have an ether bond and Ya in the formula (a10-1)^x1The same applies to the 2-valent hydrocarbon group which may have an ether bond as a substituent.

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

[ CHEM 13 ]

[ CHEM 14 ]

[ CHEM 15 ]

[ CHEM 16 ]

[ CHEM 17 ]

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

[ CHEM 18 ]

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

(A1) The proportion of the structural unit (a1) in component (a) is preferably 5 to 90 mol%, more preferably 10 to 70 mol%, particularly preferably 15 to 50 mol%, based on the total (100 mol%) of all the structural units constituting component (a 1).

By setting the ratio of the structural unit (a1) to be equal to or higher than the lower limit of the preferable range, the contrast between the exposed portion and the unexposed portion of the resist film can be further improved, and the resolution can be improved. On the other hand, by setting the upper limit value of the preferable range to be equal to or less than the upper limit value, balance with other constituent units can be obtained.

Other structural units

(A1) Component (c) may have other structural units in addition to the structural unit (a10) and the structural unit (a 1).

Examples of the other structural unit include a lactone ring-containing group and an-SO-containing group₂-a cyclic group or a carbonate-containing cyclic group-containing structural unit (a2) (wherein structural units belonging to structural unit (a10) or structural unit (a1) are excluded); a structural unit (a4) containing an acid-non-dissociable alicyclic group; a structural unit derived from styrene, a structural unit derived from a styrene derivative (wherein the structural unit belonging to the structural unit (a10) is excluded); a structural unit of an aliphatic hydrocarbon group having a polar group (wherein a structural unit belonging to any of the structural units is not included), and the like.

Structural unit (a2)

The structural unit (a2) is a lactone ring-containing group-SO-containing group₂A cyclic group or a structural unit containing a carbonate cyclic group (excluding a structural unit belonging to the structural unit (a10) or the structural unit (a 1)).

The lactone ring-containing group of the structural unit (a2) contains-SO₂When the component (a1) is used for forming a resist film, a cyclic group or a cyclic group containing carbonate is effective in improving adhesion of the resist film to a substrate. Further, by making the (a1) component have the structural unit (a2), the solubility of the resist film in an alkaline developer during development can be improved in the alkaline development process.

The "lactone ring-containing group" refers to a cyclic group containing a ring (lactone ring) containing — O — C (═ O) -, in the ring skeleton thereof. 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, there may be mentioned groups represented by the following general formulae (a2-r-1) to (a 2-r-7).

[ CHEM 19 ]

[ 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 general formulae (a2-r-1) to (a2-r-7) as 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. Specific examples 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'²¹The alkyl group in (1) is a group in which an alkyl group is bonded to an oxygen atom (-O-).

As Ra'²¹Examples of the halogen atom in (b) include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.

As Ra'²¹Examples of the haloalkyl group in (1) include the above 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 most 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, there may be mentioned 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' include the same groups as those represented by the above general formulae (a2-R-1) to (a 2-R-7).

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

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

As Ra'²¹The hydroxyalkyl group in (1) is preferably a hydroxyalkyl group having 1 to 6 carbon atoms, and concretely, the above 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 having-O-or-S-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.

[ CHEM 20 ]

[ CHEM 21 ]

"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. The ring skeleton of the catalyst contains-SO₂The ring of (E) is referred to as a first ring, and is referred to as a monocyclic group when only the ring is present, and is referred to as a polycyclic group when the ring has other ring structures. containing-SO₂The cyclic group may be a monocyclic group or a polycyclic group.

containing-SO₂The cyclic group is particularly preferably one having-O-SO in the ring skeleton₂A cyclic radical, i.e. 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).

[ CHEM 22 ]

[ 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 ', hydroxyalkyl group in (a2-R-1) to (a2-R-7) include Ra '²¹The same groups as those listed in the description of (1).

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.

[ CHEM 23 ]

[ CHEM 24 ]

[ CHEM 25 ]

The "carbonate-containing cyclic group" refers to a cyclic group containing a ring (carbonate ring) having a ring skeleton containing — O — C (═ O) -O-. 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 cyclic group containing a carbonic ester is not particularly limited, and any cyclic group containing a carbonic ester can be used. Specifically, there can be mentioned groups represented by the following general formulae (ax3-r-1) to (ax 3-r-3).

[ CHEM 26 ]

[ 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 ', hydroxyalkyl group in (a2-R-1) to (a2-R-7) include Ra '²¹The same groups as those listed in the description of (1).

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

[ CHEM 27 ]

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.

The structural unit (a2) is preferably a structural unit represented by the following general formula (a 2-1).

[ CHEM 28 ]

[ wherein R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a haloalkyl 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, carbonate ring group-containing or-SO-containing group₂-a cyclic group.]

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

As Ya²¹As the 2-valent linking group in (a), there can be mentioned the group corresponding to Ya in the above-mentioned general formula (a10-1)^x1The 2-valent linking group in (1) is the same linking group. Wherein, 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), 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 may preferably be represented by the 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) in the component (a1) is preferably 1 to 40 mol%, more preferably 2 to 20 mol%, and still more preferably 5 to 10 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 not less than the lower limit of the above preferable range, the effect of containing the structural unit (a2) can be sufficiently obtained. On the other hand, if the upper limit of the above-described preferable range is not more than the upper limit, balance with other constituent units can be obtained, and various lithographic characteristics and pattern shapes can be improved.

Structural unit (a4)

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 resist pattern formed has improved dry etching resistance. The hydrophobicity of the component (A) is improved. 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 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), and remains as it is in the structural unit.

As the structural unit (a4), for example, a structural unit derived from an acrylate containing an acid-non-dissociable alicyclic group is preferable. As the alicyclic group, a large number of groups known to be used as resin components of resist compositions for ArF excimer lasers, KrF excimer lasers (preferably for ArF excimer lasers), and the like can be used.

Particularly, at least 1 kind selected from the group consisting of tricyclodecyl group, adamantyl group, tetracyclododecyl group, isobornyl group and norbornyl group is preferable from the viewpoint of easy industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.

As the structural unit (a4), specific examples thereof include structural units represented by the following general formulae (a4-1) to (a 4-7).

[ CHEM 29 ]

[ in the formula, R^αAs before.]

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

When the component (a1) has the structural unit (a4), the proportion of the structural unit (a4) in the component (a1) is preferably 1 to 30 mol%, more preferably 3 to 20 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 (a4) to be equal to or higher than the lower limit of the above-mentioned preferable range, the effect of containing the structural unit (a4) can be sufficiently obtained. On the other hand, when the content is not more than the upper limit of the preferable range, balance with other constituent units can be easily obtained.

Structural units derived from styrene

When the component (a1) has a structural unit derived from styrene, the proportion of the structural unit derived from styrene in the component (a1) is preferably 1 to 30 mol%, more preferably 3 to 20 mol%, based on the total (100 mol%) of all the structural units constituting the component (a 1).