阅读说明：本技术 环氧化合物、抗蚀剂组合物、及图案形成方法 (Epoxy compound, resist composition, and pattern formation method ) 是由 提箸正义 谷口良辅 渡边武 松井良宪 于 2020-03-05 设计创作，主要内容包括：本发明涉及环氧化合物、抗蚀剂组合物、及图案形成方法。本发明的课题为提供无损感度而能适当地控制产生自产酸剂的酸的扩散长度的抗蚀剂组合物、及使用了该抗蚀剂组合物的图案。该课题的解决方法为以下式(1)表示的环氧化合物、及含有该环氧化合物的抗蚀剂组合物。<Image he="154" wi="700" file="DDA0002401402580000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>式中,X<Sup>1</Sup>及X<Sup>2</Sup>分别独立地为-CH<Sub>2</Sub>-或-O-。k<Sup>A</Sup>为0或1。R<Sup>1</Sup>及R<Sup>2</Sup>分别独立地为碳数4～20的叔烃基、或选自于下式中的基团。<Image he="321" wi="700" file="DDA0002401402580000012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>式中,虚线为价键。(The invention relates to an epoxy compound, a resist composition, and a pattern forming method. The invention provides a resist composition which can properly control the diffusion length of acid generated from an acid generator without damaging the sensitivity, and a pattern using the resist composition. The epoxy compound represented by the following formula (1) and a resist composition containing the epoxy compound are provided. In the formula, X 1 And X 2 Are each independently-CH 2 -or-O-. k is a radical of A Is 0 or 1. R 1 And R 2 Each independently represents a C4-20 tertiary alkyl group or a group selected from the following formulae. Wherein the dotted line is a bond.)

1. An epoxy compound represented by the following formula (1);

in the formula, X¹And X²Are each independently-CH₂-or-O-; k is a radical of^AIs 0 or 1; r¹And R²Each independently represents a C4-20 tertiary alkyl group or a group selected from the following formulae;

wherein the dotted line is a bond.

2. A resist composition comprising:

the epoxy compound according to claim 1,

a base polymer containing a repeating unit whose polarity changes by the action of an acid and at least 1 selected from the repeating units represented by the following formulae (B) to (E),

acid generators, and

an organic solvent;

in the formula, R^AIs a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; z¹A C1-20 fluoroalcohol-containing substituent; z²A C1-20 substituent containing a phenolic hydroxyl group; z³A C1-20 substituent containing a carboxyl group; z⁴Is a bagA substituent containing a lactone skeleton, a sultone skeleton, a carbonate skeleton, a cyclic ether skeleton, an acid anhydride skeleton, an alcoholic hydroxyl group, an alkoxycarbonyl group, a sulfonamide group, or a carbamoyl group; y is¹～Y⁴Each independently is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, naphthylene, -O-Y⁵-、-C(＝O)-O-Y⁵-or-C (═ O) -NH-Y⁵-, and Y⁵Is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms, a phenylene group or a naphthylene group, and may contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group.

3. The resist composition according to claim 2, wherein the base polymer further comprises at least 1 selected from the group consisting of repeating units represented by the following formulae (F1) to (F4);

in the formula, R^AIs a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; l is¹¹Is a single bond, phenylene, -O-L^11A-、-C(＝O)-O-L^11A-or-C (═ O) -NH-L^11A-, and L^11AAn alkanediyl group having 1 to 20 carbon atoms, an alkenediyl group having 2 to 20 carbon atoms or a phenylene group which may contain a hetero atom; l is¹²And L¹³Each independently represents a single bond or a C1-20 divalent hydrocarbon group which may contain a hetero atom; l is¹⁴Is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, -O-L^14A-、-C(＝O)-O-L^14Aor-C (═ O) -NH-L^14A-；L^14AIs phenylene which may also be substituted; r³¹～R⁴¹Each independently is a C1-20 hydrocarbon group which may contain a hetero atom; furthermore, L¹¹、R³¹And R³²Any 2 of which may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded, R³³、R³⁴And R³⁵Any 2 of (1), R³⁶、R³⁷And R³⁸Or any 2 of (1), or R³⁹、R⁴⁰And R⁴¹Any 2 of (3) may also beAre bonded to each other and form a ring together with the sulfur atom to which they are bonded; xc^-Is a non-nucleophilic counterion; a. the¹Is a hydrogen atom or a trifluoromethyl group; n is¹Is 0 or 1, however, L¹²Is a single bond, n¹Is 0; n is²Is 0 or 1, however, L¹³Is a single bond, n²Is 0.

4. A resist composition comprising:

the epoxy compound according to claim 1,

a base polymer containing a repeating unit whose polarity changes by the action of an acid and at least 1 selected from the repeating units represented by the following formulae (B) to (E) and at least 1 selected from the repeating units represented by the formulae (F1) to (F4), and

an organic solvent;

in the formula, R^AIs a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group; z¹A C1-20 fluoroalcohol-containing substituent; z²A C1-20 substituent containing a phenolic hydroxyl group; z³A C1-20 substituent containing a carboxyl group; z⁴Is a substituent containing a lactone skeleton, a sultone skeleton, a carbonate skeleton, a cyclic ether skeleton, an acid anhydride skeleton, an alcoholic hydroxyl group, an alkoxycarbonyl group, a sulfonamide group, or a carbamoyl group; y is¹～Y⁴Each independently is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, naphthylene, -O-Y⁵-、-C(＝O)-O-Y⁵-or-C (═ O) -NH-Y⁵-, and Y⁵An alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms, a phenylene group, or a naphthylene group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group;

in the formula, R^ATo hydrogen atomsA fluorine atom, a methyl group or a trifluoromethyl group; l is¹¹Is a single bond, phenylene, -O-L^11A-、-C(＝O)-O-L^11A-or-C (═ O) -NH-L^11A-, and L^11AAn alkanediyl group having 1 to 20 carbon atoms, an alkenediyl group having 2 to 20 carbon atoms or a phenylene group which may contain a hetero atom; l is¹²And L¹³Each independently represents a single bond or a C1-20 divalent hydrocarbon group which may contain a hetero atom; l is¹⁴Is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, -O-L^14A-、-C(＝O)-O-L^14Aor-C (═ O) -NH-L^14A-; and L is^14AIs phenylene which may also be substituted; r³¹～R⁴¹Each independently is a C1-20 hydrocarbon group which may contain a hetero atom; furthermore, L¹¹、R³¹And R³²Any 2 of which may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded, R³³、R³⁴And R³⁵Any 2 of (1), R³⁶、R³⁷And R³⁸Or any 2 of (1), or R³⁹、R⁴⁰And R⁴¹Any 2 of them may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded; xc^-Is a non-nucleophilic counterion; a. the¹Is a hydrogen atom or a trifluoromethyl group; n is¹Is 0 or 1, however, L¹²Is a single bond, n¹Is 0; n is²Is 0 or 1, however, L¹³Is a single bond, n²Is 0.

5. A method of forming a pattern, comprising the steps of:

forming a resist film on a substrate using the resist composition according to any one of claims 2 to 4,

exposing the resist film with high-energy radiation, and

and developing the exposed resist film by using a developing solution to obtain a pattern.

6. The pattern forming method according to claim 5, wherein a developer of an alkali aqueous solution is used as the developer to dissolve an exposed portion, thereby obtaining a positive pattern in which an unexposed portion is not dissolved.

7. The pattern forming method according to claim 5, wherein an organic solvent developer is used as the developer to dissolve an unexposed portion to obtain a negative pattern in which an exposed portion is not dissolved.

Technical Field

The invention relates to an epoxy compound, a resist composition and a pattern forming method.

Background

Miniaturization is rapidly progressing with high integration and high speed of LSIs. In the most advanced microfabrication technology, the field of ArF immersion lithography, in which exposure is performed by inserting a liquid such as water between a projection lens and a substrate, is used for mass production, and studies are being made on multiple exposure (multiple patterning) of ArF lithography, Extreme Ultraviolet (EUV) lithography with a wavelength of 13.5nm, and the like.

The main stream of ArF resist compositions is a so-called chemically amplified resist composition containing a base polymer and a photoacid generator as essential components. The acid generated from the acid generator by the exposure reacts with the base polymer, and the base polymer changes only in the exposed portion. Thereafter, a pattern is obtained by development with an alkali solution or an organic solvent as a developer.

In the progress of miniaturization, resist compositions used for photolithography are required to improve various characteristics such as high resolution performance and high sensitivity performance, and for example, improvement of edge roughness (LWR) of a line pattern by controlling a diffusion length of acid generated from an acid generator to a high degree has been studied.

It is believed that in order to control the diffusion length of the acid, the structure of the acid generator is first selected for a low acid diffusion design. For example, it has been proposed to select a photoacid generator designed to have a cation structure and an anion structure in the same molecule, increase the molecular weight of the generated acid, and the like, to achieve low diffusion of the generated acid. However, there are drawbacks in lithographic performance such as insufficient solubility in a solvent of an acid generator having a low sensitivity and a high molecular weight and solubility in an aqueous alkali solution, and it is technically difficult to achieve both low acid diffusion and high sensitivity (patent document 1). Next, studies have been made to improve the design of a salt compound using an amine compound or an acid having a low degree of acidity as a quencher. Although the excellent acid diffusion length can be controlled in proportion to the amount of the quencher added, the sensitivity of the resist composition is inevitably lowered, and it is not necessarily satisfactory in requiring a high processing amount in the photolithography step (patent documents 2 to 3).

Disclosure of Invention

Problems to be solved by the invention

As miniaturization progresses, studies on both low acid diffusion and high sensitivity have been conventionally conducted mainly by improving the structure of an acid generator and a quencher, but as described above, low acid diffusion and high sensitivity are in a trade-off relationship, and it is not necessarily sufficient from the viewpoint of satisfying various performances represented by resolution, roughness, and resist pattern shape at the same time.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a resist composition which can appropriately control the diffusion length of an acid generated from an acid generator without impairing the sensitivity, and a pattern using the resist composition.

Means for solving the problems

The present inventors have made extensive studies to achieve the above-mentioned object, and as a result, have obtained the following findings; when a predetermined epoxy compound is used as an additive of a resist composition in combination with an acid generator, the diffusion length of an acid generated from the acid generator can be appropriately controlled, and it is effective to achieve both low acid diffusion and high sensitivity.

Accordingly, the present invention provides the following epoxy compound, resist composition and pattern forming method.

1. An epoxy compound represented by the following formula (1).

[ solution 1]

In the formula, X¹And X²Are each independently-CH₂-or-O-. k is a radical of^AIs 0 or 1. R¹And R²Each independently represents a C4-20 tertiary alkyl group or a group selected from the following formulae.

[ solution 2]

Wherein the dotted line is a bond.

2. A resist composition comprising:

an epoxy compound of the formula 1,

a base polymer containing a repeating unit whose polarity changes by the action of an acid and at least 1 selected from the repeating units represented by the following formulae (B) to (E),

acid generators, and

an organic solvent.

[ solution 3]

In the formula, R^AIs a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Z¹A C1-20 fluoroalcohol-containing substituent. Z²A C1-20 substituent containing a phenolic hydroxyl group. Z³A C1-20 substituent containing a carboxyl group. Z⁴Is a substituent containing a lactone skeleton, a sultone skeleton, a carbonate skeleton, a cyclic ether skeleton, an acid anhydride skeleton, an alcoholic hydroxyl group, an alkoxycarbonyl group, a sulfonamide group or a carbamoyl group. Y is¹～Y⁴Each independently is a single bond, methylene, ethylene, phenyleneFluorinated phenylene, naphthylene, -O-Y⁵-、-C(＝O)-O-Y⁵-or-C (═ O) -NH-Y⁵-, and Y⁵Is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms, a phenylene group or a naphthylene group, and may contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group.

3. The resist composition according to claim 2, wherein the base polymer further contains at least 1 selected from the group consisting of repeating units represented by the following formulae (F1) to (F4).

[ solution 4]

In the formula, R^AIs a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. L is¹¹Is a single bond, phenylene, -O-L^11A-、-C(＝O)-O-L^11A-or-C (═ O) -NH-L^11A-, and L^11AIs an alkanediyl group having 1 to 20 carbon atoms, an alkenediyl group having 2 to 20 carbon atoms or a phenylene group which may contain a hetero atom. L is¹²And L¹³Each independently represents a single bond or a C1-20 hydrocarbon group having a valence of 2 which may contain a hetero atom. L is¹⁴Is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, -O-L^14A-、-C(＝O)-O-L^14Aor-C (═ O) -NH-L^14A-。L^14AIs phenylene which may also be substituted. R³¹～R⁴¹Each independently is a C1-20 hydrocarbon group which may contain a hetero atom. Furthermore, L¹¹、R³¹And R³²Any 2 of which may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded, R³³、R³⁴And R³⁵Any 2 of (1), R³⁶、R³⁷And R³⁸Or any 2 of (1), or R³⁹、R⁴⁰And R⁴¹Any 2 of them may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. Xc^-Is a non-nucleophilic counterion. A. the¹Is a hydrogen atom or a trifluoromethyl group. n is¹Is 0 or 1, however, L¹²Is a single bond, n¹Is 0. n is²Is 0 or 1, however, L¹³Is a single bond, n²Is 0.

4. A resist composition comprising:

an epoxy compound of the formula 1,

a base polymer containing a repeating unit whose polarity changes by the action of an acid and at least 1 selected from the repeating units represented by the following formulae (B) to (E) and at least 1 selected from the repeating units represented by the formulae (F1) to (F4), and

an organic solvent.

[ solution 5]

In the formula, R^A、Z¹～Z⁴、Y¹～Y⁴As before.

[ solution 6]

In the formula, R^A、L¹¹～L¹⁴、R³¹～R⁴¹、Xc^-、A¹、n¹And n²As before.

5. A method of forming a pattern, comprising the steps of:

forming a resist film on a substrate using the resist composition according to any one of claims 2 to 4,

exposing the resist film with a high-energy radiation, and

the exposed resist film is developed with a developer to obtain a pattern.

6. The pattern forming method according to the above 5, wherein a developer of an alkali aqueous solution is used as the developer to dissolve an exposed portion, thereby obtaining a positive pattern in which an unexposed portion is not dissolved.

7. The pattern forming method according to claim 5, wherein an organic solvent developer is used as the developer to dissolve an unexposed portion, thereby obtaining a negative pattern in which an exposed portion is not dissolved.

Invention of the inventionEffect of (1)

The epoxy compound of the present invention is particularly useful for resist compositions for ArF lithography, EB lithography and EUV lithography, and can suitably control the diffusion length of an acid generated from an acid generator, and is effective for both low acid diffusion and high sensitivity, and can achieve a good LWR.

Drawings

FIG. 1 shows the preparation of an epoxy compound EP-1 obtained in example 1-1¹H-NMR spectrum.

FIG. 2 shows the epoxy compound EP-X obtained in comparative example 1-1¹H-NMR spectrum.

Detailed Description

The present invention will be described in detail below. In addition, enantiomers and diastereomers may exist in the chemical structures in the following chemical formulae, but if not specifically mentioned, all of these stereoisomers are represented by the respective chemical formulae. In addition, these stereoisomers may be used alone in 1, also can be used in a mixture form.

[ epoxy Compound ]

The epoxy compound of the present invention is represented by the following formula (1).

[ solution 7]

In the formula (1), X¹And X²Are each independently-CH₂-or-O-. k is a radical of^AIs 0 or 1. R¹And R²Each independently represents a C4-20 tertiary alkyl group or a group selected from the following formulae.

[ solution 8]

Wherein the dotted line is a bond.

In the tertiary hydrocarbon group having 4 to 20 carbon atoms, the carbon atom bonded to the ester oxygen atom is a tertiary carbon atom. The tertiary hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The tertiary hydrocarbon group may contain an aromatic group. Examples of the tertiary hydrocarbon group having 4 to 20 carbon atoms include groups represented by the following formulae (L3) to (L9).

The epoxy compound represented by the formula (1) includes, but is not limited to, the following compounds. In the following formula, X¹And X²As before.

[ solution 9]

[ solution 10]

The method for obtaining the epoxy compound of the present invention may be exemplified by: a method of converting a double bond moiety into an epoxide by subjecting an olefin compound (pr-1) which is a precursor obtainable by a known method to an oxidation reaction. The reaction scheme is shown below, but the method for obtaining the epoxy compound is not limited thereto.

[ solution 11]

In the formula, X¹、X²、R¹、R²And k^AAs before.

The method for oxidizing the olefin compound (pr-1) as the precursor may be, for example, an aqueous hydrogen peroxide solution, or may be an optimum method selected from known oxidation methods such as a reaction of a peroxide of an organic carboxylic acid such as performic acid, peracetic acid or m-chloroperoxybenzoic acid with a transition metal catalyst and a transition metal oxide obtained by combining the above peroxide with a transition metal catalyst. Among them, it is preferable to use an aqueous hydrogen peroxide solution or a peroxide of an organic carboxylic acid, which is capable of reacting under mild conditions of room temperature to about 40 ℃ and does not require a complicated production process.

The oxidation reaction is preferably carried out by following the reaction by Gas Chromatography (GC) or silica gel Thin Layer Chromatography (TLC) and then completing the reaction, and is usually about 1 to 72 hours from the viewpoint of the yield. The epoxy compound can be obtained by subjecting the reaction mixture to a usual aqueous treatment (aqueous work-up), and if necessary, the epoxy compound can be purified by a usual method such as distillation, chromatography, recrystallization, or the like.

[ resist composition ]

The resist composition of the present invention contains an epoxy compound represented by formula (1), a base polymer, an acid generator, and an organic solvent. The acid generator may be a polymer-bonded acid generator integrated with the base polymer, or an additive acid generator which is different from the base polymer. In the case of a polymer-bonded acid generator, the base polymer functions as a base polymer and also as an acid generator.

The epoxy compound represented by the formula (1) functions as a sensitivity adjuster in a resist composition. Generally, epoxy compounds have a less moderate action than so-called quenchers for strong acids, such as amines and salt compounds of weak acids, in resist compositions, but have the effect of inhibiting the diffusion of acids generated from acid generators by exposure. The aforementioned epoxy compound is characterized in that: in addition to the epoxy ring, the compound has a 4-ring condensed ring skeleton and is more acid-labile alkoxycarbonyl. By using the epoxy compound as an additive in a resist composition, the diffusion of an excessive amount of acid can be appropriately suppressed, which contributes to the improvement of the contrast of exposed portions and unexposed portions in a line and space pattern (line and space pattern), and a good pattern with a small LWR can be formed. It is presumed that the rigid 4-ring condensed ring structure contributes to adjustment of the migration ability or the kinetic property of the epoxy compound itself at the time of the post-exposure heat treatment step (post-exposure bake: PEB) in the resist film, and as a result, the reactivity or the activity of the epoxy compound with respect to the acid molecule is adjusted to be appropriate. Further, the epoxy compound of the present invention contains an acid labile group structure, and therefore the acid labile group can react to the action of the generated acid molecules in an excessive amount by diffusion, which is not easily completely inhibited by only the epoxy group. Therefore, it is presumed that the undesirable acid catalyst elimination reaction of the acid labile group of the base polymer at the unexposed portion can be suppressed, and that the epoxy compound after suppressing the action of the acid generates a carboxylic acid group of high polarity, for example, becomes soluble in an aqueous alkali solution, and contributes to the improvement of the soluble-insoluble solubility contrast at the time of development of the boundary between the exposed portion and the unexposed portion.

In the resist composition of the present invention, the content of the epoxy compound is preferably 0.001 to 10 parts by mass, and more preferably 0.01 to 5 parts by mass, relative to 80 parts by mass of a base polymer described later. The epoxy compounds can be used alone in 1 or more than 2. Further, by using a quencher such as an amine or an onium salt compound of a weak acid in combination, improvement of the lithographic performance of the conventional resist composition can be expected.

[ base Polymer ]

The base polymer used in the resist composition of the present invention contains a repeating unit whose polarity changes by the action of an acid (hereinafter, repeating unit a is referred to).

As the monomer providing the repeating unit A, a monomer represented by the following formula (A-1) or (A-2) may be mentioned.

[ solution 12]

In the formulae (A-1) and (A-2), R^AIs a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. X^AIs an acid labile group. R¹¹Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may contain an ether bond or a carbonyl group. L is¹Is a single bond, carbonyloxy or amido. L is²A single bond, or an alkanediyl group having 1 to 7 carbon atoms which may contain an ether bond or a carbonyl group. a is an integer satisfying a is less than or equal to 5+2 c-b. b is an integer of 1 to 5. c is an integer of 0 to 2.

In the formula (A-2), R¹¹The alkyl group having 1 to 6 carbon atoms which may contain an ether bond or a carbonyl group is represented by: methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, cyclopentyl, cyclohexyl, or the following groups, but are not limited thereto.

[ solution 13]

Wherein the dotted line is a bond.

In the formula (A-2), L²The alkanediyl group having 1 to 7 carbon atoms which may contain an ether bond or a carbonyl group includes: methylene, ethylene, propane-1, 3-diyl, butane-1, 4-diyl, pentane-1, 5-diyl, hexane-1, 6-diyl, heptane-1, 7-diyl, or the following group, but not limited thereto.

[ solution 14]

Wherein the dotted line is a bond.

The polymer containing a repeating unit derived from the monomer represented by the formula (A-1) or (A-2) is decomposed by the action of an acid to generate a carboxyl group or a phenolic hydroxyl group, and is alkali-soluble. Various acid labile groups X may be used^ASpecific examples thereof include groups represented by the following formulas (L1) to (L9), tertiary alkyl groups having 4 to 20 carbon atoms, more preferably 4 to 15 carbon atoms, trialkylsilyl groups each having an alkyl group having 1 to 6 carbon atoms, and oxoalkyl groups having 4 to 20 carbon atoms.

[ solution 15]

Wherein the dotted line is a bond.

In the formula (L1), R^L01And R^L02Each independently represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms. The alkyl group may be linear, branched or cyclic, and specific examples thereof include: methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, n-octyl, norbornyl, tricyclodecyl, tetracyclododecyl, adamantyl, and the like.

In the formula (L1), R^L03The C1-to C18-valent hydrocarbon group which may contain a hetero atom is preferably 1-to C10. The aforementioned hetero atoms may be exemplified by: oxygen atom, nitrogen atom, sulfur atom, etc. The above-mentioned 1-valent hydrocarbon group can be exemplified by: a linear, branched or cyclic alkyl group, a group in which a part of hydrogen atoms of these groups is substituted with a hydroxyl group, an alkoxy group, an oxo group, an amino group, an alkylamino group or the like, a group in which a part of carbon atoms of these groups is substituted with a hetero atom group such as an oxygen atom or the like, and the like. The aforementioned alkyl groups are exemplified by those mentioned above as R^L01And R^L02The alkyl group is the same as the above-mentioned alkyl group. Examples of the substituted alkyl group include the groups shown below.

[ solution 16]

Wherein the dotted line is a bond.

R^L01And R^L02、R^L01And R^L03Or R^L02And R^L03Or may be bonded to each other to form a ring together with the carbon atom and oxygen atom to which they are bonded, and when forming a ring, the group to which they are bonded is a linear or branched alkanediyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms.

In the formula (L2), R^L04A C4-20 tertiary alkyl group, preferably C4-15 tertiary alkyl group, a trialkylsilyl group in which each alkyl group is an alkyl group having C1-6 carbon atoms, an oxoalkyl group having C4-20 carbon atoms, or a group represented by the formula (L1). k is an integer of 0 to 6.

Examples of the tertiary alkyl group include: t-butyl, t-pentyl, 1-diethylpropyl, 2-cyclopentylpropan-2-yl, 2-cyclohexylpropan-2-yl, 2- (bicyclo [2.2.1] heptan-2-yl) propan-2-yl, 2- (adamantan-1-yl) propan-2-yl, 1-ethylcyclopentyl, 1-butylcyclopentyl, 1-ethylcyclohexyl, 1-butylcyclohexyl, 1-ethyl-2-cyclopentenyl, 1-ethyl-2-cyclohexenyl, 2-methyl-2-adamantyl, 2-ethyl-2-adamantyl, and the like. The above-mentioned trialkylsilyl group may be exemplified by: trimethylsilyl, triethylsilyl, dimethyl-t-butylsilyl, and the like. Examples of the oxoalkyl group include: 3-oxocyclohexyl, 4-methyl-2-oxooxacyclohex-4-yl, 5-methyl-2-oxooxacyclopent-5-yl and the like.

In the formula (L3), R^L05The alkyl group having 1 to 8 carbon atoms which may contain a hetero atom, or the aryl group having 6 to 20 carbon atoms which may contain a hetero atom. The alkyl group may be linear, branched or cyclic, and specific examples thereof include: methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, cyclopentyl, cyclohexyl and the like, a part of hydrogen atoms of which may be substituted with hydroxy, alkoxy, carboxy, alkoxycarbonyl, oxo, amino, alkylamino, cyano, mercapto, alkylthio, sulfo and the like. The aforementioned aryl groups include: phenyl, methylphenyl, naphthyl, anthryl, phenanthryl, pyrenyl and the like. In the formula (L3), m is 0 or 1, n is an integer of 0 to 3, and 2m + n is 2 or 3.

In the formula (L4), R^L06The alkyl group having 1 to 10 carbon atoms which may contain a hetero atom, or the aryl group having 6 to 20 carbon atoms which may contain a hetero atom. Specific examples of the aforementioned alkyl and aryl groups are listed under R^L05The same groups as those described in the description of (1) are alkyl groups and aryl groups.

In the formula (L4), R^L07～R^L16Each independently represents a hydrogen atom or a C1-valent hydrocarbon group having 1 to 15 carbon atoms. The 1-valent hydrocarbon group may be any of linear, branched, and cyclic, and specific examples thereof include: and linear, branched or cyclic alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, and cyclohexylbutyl groups, and some of the hydrogen atoms of these groups may be substituted with hydroxyl, alkoxy, carboxyl, alkoxycarbonyl, oxo, amino, alkylamino, cyano, mercapto, alkylthio, and sulfo groups. R^L07～R^L162 selected from them may also be bonded to each other and form a ring together with the carbon atom to which they are bonded (e.g. R)^L07And R^L08、R^L07And R^L09、R^L08And R^L10、R^L09And R^L10、R^L11And R^L12、R^L13And R^L14Etc.), in this case, the group participating in the ring formation is a 2-valent hydrocarbon group having 1 to 15 carbon atoms. Examples of the 2-valent hydrocarbon group include a 2-valent hydrocarbon group obtained by removing 1 hydrogen atom from the 1-valent hydrocarbon group listed above. Furthermore, R^L07～R^L16In the case of carbon-bonded carbon copolymers, the adjacent carbon atoms may be bonded to each other without any structure, or a double bond (e.g., R) may be formed^L07And R^L09、R^L09And R^L15、R^L13And R^L15Etc.).

In the formula (L5), R^L17～R^L19Each independently an alkyl group having 1 to 15 carbon atoms. The alkyl group may be linear, branched or cyclic, and specific examples thereof include: methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, n-octyl, 1-adamantyl, 2-adamantyl, and the like.

In the formula (L6), R^L20The alkyl group having 1 to 10 carbon atoms which may contain a hetero atom, or the aryl group having 6 to 20 carbon atoms which may contain a hetero atom. Specific examples of the aforementioned alkyl and aryl groups are listed under R^L05The same groups as those described in the description of (1) are alkyl groups and aryl groups.

In the formula (L7), R^L21The alkyl group having 1 to 10 carbon atoms which may contain a hetero atom, or the aryl group having 6 to 20 carbon atoms which may contain a hetero atom. Specific examples of the aforementioned alkyl and aryl groups are listed under R^L05The same groups as those described in the description of (1) are alkyl groups and aryl groups. R^L22And R^L23Each independently represents a hydrogen atom or a C1-valent hydrocarbon group having 1 to 10 carbon atoms. The 1-valent hydrocarbon group may be linear, branched or cyclic, and specific examples thereof include^L07～R^L16The same groups as described in the description of (1) are hydrocarbon groups having a valence of 1. Furthermore, R^L22And R^L23Or may be bonded to each other and form, together with the carbon atom to which they are bonded, a substituted or unsubstituted cyclopentane ring or a substituted or unsubstituted cyclohexane ring. R^L24Is taken together with the carbon atom to which it is bonded to form a substituted or unsubstituted cyclopentane ring, a substituted or unsubstituted cyclohexane ring, or a substituted or unsubstitutedThe 2-valent radical of the norbornane ring. s is 1 or 2.

In the formula (L8), R^L25The alkyl group having 1 to 10 carbon atoms which may contain a hetero atom, or the aryl group having 6 to 20 carbon atoms which may contain a hetero atom. Specific examples of the aforementioned alkyl and aryl groups are listed under R^L05The same groups as those described in the description of (1) are alkyl groups and aryl groups. R^L26And R^L27Each independently represents a hydrogen atom or a C1-valent hydrocarbon group having 1 to 10 carbon atoms. The 1-valent hydrocarbon group may be linear, branched or cyclic, and specific examples thereof include^L07～R^L16The same groups as described in the description of (1) are hydrocarbon groups having a valence of 1. Furthermore, R^L26And R^L27Or may be bonded to each other and form, together with the carbon atom to which they are bonded, a substituted or unsubstituted cyclopentane ring or a substituted or unsubstituted cyclohexane ring. R^L28Is a 2-valent group which forms a substituted or unsubstituted cyclopentane ring, a substituted or unsubstituted cyclohexane ring, or a substituted or unsubstituted norbornane ring together with the carbon atom to which it is bonded. t is 1 or 2.

In the formula (L9), R^L29The alkyl group having 1 to 10 carbon atoms which may contain a hetero atom, or the aryl group having 6 to 20 carbon atoms which may contain a hetero atom. Specific examples of the aforementioned alkyl and aryl groups are listed under R^L05The same groups as those described in the description of (1) are alkyl groups and aryl groups. R^L30And R^L31Each independently represents a hydrogen atom or a C1-valent hydrocarbon group having 1 to 10 carbon atoms. The 1-valent hydrocarbon group may be linear, branched or cyclic, and specific examples thereof include^L07～R^L16The same groups as described in the description of (1) are hydrocarbon groups having a valence of 1. Furthermore, R^L30And R^L31Or may be bonded to each other and form, together with the carbon atom to which they are bonded, a substituted or unsubstituted cyclopentane ring or a substituted or unsubstituted cyclohexane ring. R^L32Is a 2-valent group which forms a substituted or unsubstituted cyclopentane ring, a substituted or unsubstituted cyclohexane ring, or a substituted or unsubstituted norbornane ring together with the carbon atom to which it is bonded.

Among the acid-labile groups represented by formula (L1), examples of the linear or branched acid-labile groups include, but are not limited to, the following groups.

[ solution 17]

Wherein the dotted line is a bond.

Examples of the cyclic acid-labile group in the acid-labile group represented by formula (L1) include: tetrahydrofuran-2-yl, 2-methyltetrahydrofuran-2-yl, tetrahydropyran-2-yl, 2-methyltetrahydropyran-2-yl, and the like.

The acid-labile group represented by formula (L2) may be exemplified by: t-butoxycarbonyl, t-butoxycarbonylmethyl, t-pentyloxycarbonyl, t-pentyloxycarbonylmethyl, 1-diethylpropoxycarbonyl, 1-diethylpropoxycarbonylmethyl, 1-ethylcyclopentyloxycarbonyl, 1-ethylcyclopentyloxycarbonylmethyl, 1-ethyl-2-cyclopentenyloxycarbonyl, 1-ethyl-2-cyclopentenyloxycarbonylmethyl, 1-ethoxyethoxycarbonylmethyl, 2-tetrahydropyranyloxycarbonylmethyl, 2-tetrahydrofuranylmethyl and the like.

The acid-labile group represented by formula (L3) may be exemplified by: 1-methylcyclopentyl, 1-ethylcyclopentyl, 1-n-propylcyclopentyl, 1-isopropylcyclopentyl, 1-n-butylcyclopentyl, 1-sec-butylcyclopentyl, 1-tert-butylcyclopentyl, 1-cyclohexylcyclopentyl, 1- (4-methoxy-n-butyl) cyclopentyl, 1-methylcyclohexyl, 1-ethylcyclohexyl, 3-methyl-1-cyclopenten-3-yl, 3-ethyl-1-cyclopenten-3-yl, 3-methyl-1-cyclohexen-3-yl, 3-ethyl-1-cyclohexen-3-yl, and the like.

The acid-labile group represented by formula (L4) is particularly preferably a group represented by the following formulae (L4-1) to (L4-4).

[ solution 18]

In the formulae (L4-1) to (L4-4), the dotted line indicates the bonding position and bonding direction. R^L41Each independently is a C1-10 hydrocarbon group. The 1-valent hydrocarbon group may be any of linear, branched, and cyclic, and specific examples thereof include: first of allAnd a linear, branched or cyclic alkyl group such as an ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, tert-pentyl group, n-hexyl group, cyclopentyl group, or cyclohexyl group.

Stereoisomers (enantiomers or diastereomers) may be present in the groups represented by the formulae (L4-1) to (L4-4), but all of these stereoisomers are represented by the formulae (L4-1) to (L4-4). Acid labile group X^AWhen the group is represented by the formula (L4), a plurality of stereoisomers may be contained.

For example, the compound represented by the formula (L4-3) represents 1 or a mixture of 2 selected from the group represented by the following formulae (L4-3-1) and (L4-3-2).

[ solution 19]

In the formula, R^L41As before. The dotted line indicates the bonding position and bonding direction.

Further, the compound represented by the formula (L4-4) represents 1 or a mixture of 2 or more selected from the group represented by the following formulae (L4-4-1) to (L4-4-4).

[ solution 20]

In the formula, R^L41As before. The dotted line indicates the bonding position and bonding direction.

The compounds represented by formulae (L4-1) to (L4-4), (L4-3-1), (L4-3-2), and formulae (L4-4-1) to (L4-4-4) also represent their enantiomers and mixtures of enantiomers.

Further, the high reactivity in the acid catalyst elimination reaction is achieved by setting the bonding directions of the formulae (L4-1) to (L4-4), (L4-3-1), (L4-3-2), and (L4-4-1) to (L4-4-4) to exo sides with respect to the bicyclo [2.2.1] heptane ring, respectively (see Japanese patent application laid-open No. 2000-336121). In the production of a monomer having a tertiary exo-alkyl group having a bicyclo [2.2.1] heptane skeleton as a substituent, a monomer substituted with an endo-alkyl group represented by the following formulae (L4-1-endo) to (L4-4-endo) may be contained in some cases, but in order to achieve good reactivity, the exo ratio is preferably 50 mol% or more, and more preferably 80 mol% or more.

[ solution 21]

In the formula, R^L41As before. The dotted line indicates the bonding position and bonding direction.

The acid-labile group represented by formula (L4) includes, but is not limited to, the following groups.

[ solution 22]

In the formula, the dotted line represents the bonding position and bonding direction.

The acid-labile group represented by formula (L5) may be exemplified by: t-butyl, t-amyl, groups shown below, but not limited thereto.

[ solution 23]

Wherein the dotted line is a bond.

The acid-labile group represented by formula (L6) includes, but is not limited to, the following groups.

[ solution 24]

Wherein the dotted line is a bond.

The acid-labile group represented by formula (L7) includes, but is not limited to, the following groups.

[ solution 25]

Wherein the dotted line is a bond.

The acid-labile group represented by formula (L8) includes, but is not limited to, the following groups.

[ solution 26]

Wherein the dotted line is a bond.

The acid-labile group represented by formula (L9) includes, but is not limited to, the following groups.

[ solution 27]

Wherein the dotted line is a bond.

Further, X^AAmong the acid-labile groups represented by the formula, a C4-20 tertiary alkyl group, a C1-6 trialkylsilyl group for each alkyl group, and an C4-20 oxoalkyl group are each represented by R^L04The same groups as those described in the description of (1).

The monomer represented by the formula (A-1) includes, but is not limited to, the following monomers. In the following formula, R^AAs before.

[ solution 28]

[ solution 29]

[ solution 30]

[ solution 31]

[ solution 32]

The monomer represented by the formula (A-2) includes, but is not limited to, the following monomers. In the following formula, R^AAs before.

[ solution 33]

[ chemical 34]

[ solution 35]

[ solution 36]

[ solution 37]

[ solution 38]

[ solution 39]

[ solution 40]

The base polymer further contains at least 1 repeating unit selected from the group consisting of a repeating unit represented by the following formula (B) (hereinafter, a repeating unit B is also referred to), a repeating unit represented by the following formula (C) (hereinafter, a repeating unit C is also referred to), a repeating unit represented by the following formula (D) (hereinafter, a repeating unit D is also referred to), and a repeating unit represented by the following formula (E) (hereinafter, a repeating unit E is also referred to).

[ solution 41]

In the formulae (B) to (D), R^AIs a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Z¹A C1-20 fluoroalcohol-containing substituent. Z²A C1-20 substituent containing a phenolic hydroxyl group. Z³A C1-20 substituent containing a carboxyl group. Z⁴Is a substituent containing a lactone skeleton, a sultone skeleton, a carbonate skeleton, a cyclic ether skeleton, an acid anhydride skeleton, an alcoholic hydroxyl group, an alkoxycarbonyl group, a sulfonamide group or a carbamoyl group. Y is¹～Y⁴Each independently is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, naphthylene, -O-Y⁵-、-C(＝O)-O-Y⁵-or-C (═ O) -NH-Y⁵-, and Y⁵Is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms, a phenylene group or a naphthylene group, and may contain a carbonyl group, an ester bond, an ether bond or a hydroxyl group.

The repeating unit B has a fluoroalcohol-containing substituent having 1 to 20 carbon atoms and having a high affinity with an aqueous alkali solution. Preferable examples of the fluoroalcohol-containing unit include repeating units containing a 1,1,1,3,3, 3-hexafluoro-2-propanol residue, a 2-hydroxy-2-trifluoromethyloxalane structure and the like as described in Japanese patent laid-open Nos. 2007-297590, 2008-111103, 2008-122932 and 2012-128067.

The fluoroalcohol-containing unit corresponding to formula (B) may be generated by first protecting the fluoroalcohol with an acyl group or an acid labile group, and then hydrolyzing the protected fluoroalcohol with a developer of an aqueous alkali solution or deprotecting the protected fluoroalcohol with an acid after exposure. In this case, preferable repeating units include those described in paragraphs [0036] to [0040] of Japanese patent application laid-open No. 2012 and 128067, and those represented by the formulae (2a), (2b) and (2f) in paragraph [0041] of the same publication.

The monomer providing the repeating unit B includes, but is not limited to, the following monomers. In the following formula, R^AAs before.

[ solution 42]

The repeating unit C is a unit having a phenolic hydroxyl group, and examples thereof include a unit derived from a monomer represented by the following formula (C-1).

[ solution 43]

In the formula, R^AAs before. R²¹Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may contain an ether bond or a carbonyl group. L is³Is a single bond, carbonyloxy or amido. L is⁴A single bond, or an alkanediyl group having 1 to 7 carbon atoms which may contain an ether bond or a carbonyl group. d is an integer satisfying d ≦ 5+2 f-e. e is an integer of 1 to 5. f is an integer of 0 to 2.

In the formula (C-1), R²¹The alkyl group having 1 to 6 carbon atoms which may contain an ether bond or a carbonyl group is represented by: methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, cyclopentyl, cyclohexyl, or the following groups, but are not limited thereto.

[ solution 44]

Wherein the dotted line is a bond.

In the formula (C-1), L⁴The alkanediyl group having 1 to 7 carbon atoms which may contain an ether bond or a carbonyl group includes: methylene, ethylene, propane-1, 3-diyl, butane-1, 4-diyl, pentane-1, 5-diyl, hexane-1, 6-diyl, heptane-1, 7-diyl, or the following group, but not limited thereto.

[ solution 45]

Wherein the dotted line is a bond.

The monomer providing the repeating unit C includes, but is not limited to, the following monomers. In the following formula, R^AAs before.

[ solution 46]

[ solution 47]

[ solution 48]

The repeating unit D is a repeating unit having a carboxyl group, and examples thereof include a repeating unit derived from a monomer represented by the following formula. In the following formula, R^AAs before.

[ solution 49]

The repeating unit E is a unit containing a lactone skeleton, a sultone skeleton, a carbonate skeleton, a cyclic ether skeleton, an acid anhydride skeleton, an alcoholic hydroxyl group, an alkoxycarbonyl group, a sulfonamide group, or a carbamoyl group.

Monomers providing repeating unit E are listed asThe monomers shown below, but are not limited thereto. In the following formula, R^AMe is methyl, as before.

[ solution 50]

[ solution 51]

[ solution 52]

[ Hua 53]

[ solution 54]

When the base polymer is a polymer-bonded acid generator, the base polymer further contains at least 1 selected from the group consisting of a repeating unit represented by the following formula (F1) (hereinafter, the repeating unit F1 is also referred to), a repeating unit represented by the following formula (F2) (hereinafter, the repeating unit F2 is also referred to), a repeating unit represented by the following formula (F3) (hereinafter, the repeating unit F3 is also referred to), and a repeating unit represented by the following formula (F4) (hereinafter, the repeating unit F4 is also referred to). When the resist composition of the present invention contains an additive acid generator described later, the base polymer may or may not contain the repeating units F1 to F4.

[ solution 55]

In the formulae (F1) to (F4), R^AIs a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. L is¹¹Is a single bond, phenylene, -O-L^11A-、-C(＝O)-O-L^11A-or-C (═ O) -NH-L^11A-。L^11AIs an alkanediyl group having 1 to 20 carbon atoms, an alkenediyl group having 2 to 20 carbon atoms or a phenylene group which may contain a hetero atom. L is¹²And L¹³Each independently represents a single bond or a C1-20 hydrocarbon group having a valence of 2 which may contain a hetero atom. L is¹⁴Is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, -O-L^14A-、-C(＝O)-O-L^14Aor-C (═ O) -NH-L^14A-。L^14AIs phenylene which may also be substituted.

L^11AThe alkanediyl group may be any of linear, branched and cyclic, and specific examples thereof include: methylene, ethane-1, 1-diyl, ethane-1, 2-diyl, propane-2, 2-diyl, propane-1, 3-diyl, 2-methylpropane-1, 3-diyl, butane-2, 3-diyl, butane-1, 4-diyl, pentane-1, 3-diyl, pentane-1, 4-diyl, 2-dimethylpropane-1, 3-diyl, pentane-1, 5-diyl, hexane-1, 6-diyl, cyclopentane-1, 2-diyl, cyclopentane-1, 3-diyl, cyclohexane-1, 4-diyl, and the like. Furthermore, L¹¹The alkenyldiyl group may be any of linear, branched and cyclic, and specific examples thereof include: ethylene-1, 2-diyl, 1-propylene-1, 3-diyl, 2-butene-1, 4-diyl, 1-methyl-1-butene-1, 4-diyl, 2-cyclohexene-1, 4-diyl, etc.

L¹²And L¹³The 2-valent hydrocarbon group represented may be any of linear, branched and cyclic, and specific examples thereof include the alkanediyl and alkenediyl groups described above.

In the formulae (F1) to (F4), R³¹～R⁴¹Each independently is a C1-20 hydrocarbon group which may contain a hetero atom. The 1-valent hydrocarbon group may be any of linear, branched, and cyclic, and specific examples thereof include: alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl; 1-valent saturated aliphatic cyclic hydrocarbon groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, adamantyl and the like; alkenyl groups such as vinyl, allyl, propenyl, butenyl, hexenyl, and the like; cyclohexenyl and the likeA 1-valent unsaturated aliphatic cyclic hydrocarbon group; aryl groups such as phenyl and naphthyl; heteroaryl groups such as thienyl; aralkyl groups such as benzyl, 1-phenylethyl and 2-phenylethyl. Among them, preferred is an aryl group. Further, some of the hydrogen atoms of these groups may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and some of the carbon atoms of these groups may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, a hydroxyl group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride, a halogenated alkyl group, etc. may be contained.

L¹¹、R³¹And R³²Any 2 of which may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded, R³³、R³⁴And R³⁵Any 2 of (1), R³⁶、R³⁷And R³⁸Or any 2 of (1), or R³⁹、R⁴⁰And R⁴¹Any 2 of them may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded.

In the formula (F1), Xc^-Is a non-nucleophilic counterion. Examples of the non-nucleophilic counter ion include: halide ions such as chloride ions and bromide ions; fluoroalkyl sulfonate ions such as trifluoromethanesulfonate ion, 1,1, 1-trifluoroethane sulfonate ion, and nonafluorobutane sulfonate ion; arylsulfonate ions such as a toluenesulfonate ion, a benzenesulfonate ion, a 4-fluorobenzenesulfonate ion, and a 1,2,3,4, 5-pentafluorobenzenesulfonate ion; alkylsulfonate ions such as methanesulfonate ion and butanesulfonate ion; imide acid group ions such as bis (trifluoromethylsulfonyl) imide ion, bis (perfluoroethylsulfonyl) imide ion, and bis (perfluorobutylsulfonyl) imide ion; and methide acid ions such as tris (trifluoromethylsulfonyl) methide ion and tris (perfluoroethylsulfonyl) methide ion.

Further, Xc^-Examples of the non-nucleophilic counter ion include anions represented by the following formula (F5) or (F6).

[ solution 56]

In the formulae (F5) and (F6), R⁵¹And R⁵²Each independently is a C1-40 hydrocarbon group which may contain a hetero atom. A. the²Is a hydrogen atom or a trifluoromethyl group. The C1-valent hydrocarbon group having 1 to 40 carbon atoms may be any of straight-chain, branched, and cyclic.

In the formula (F2), A¹Is a hydrogen atom or a trifluoromethyl group. A specific structure of the anion in the formula (F2) can be exemplified by the paragraph [0021 ] in Japanese patent laid-open publication No. 2014-177407]～[0026]The structure described. Furthermore, A¹As a specific structure of the anion in the case of a hydrogen atom, a paragraph [0021 ] of Japanese patent laid-open No. 2010-116550 can be mentioned]～[0028]The structure described above; a. the¹Specific structure of anion in the case of trifluoromethyl is described in paragraph [0021 ] of Japanese patent application laid-open No. 2010-77404]～[0027]The structure described.

Specific structure of anion in formula (F3) includes-CH (A) in the specific example of formula (F2)¹)CF₂SO₃ ^-Is substituted with-C (CF)₃)₂CH₂SO₃ ^-And the structure is formed.

Examples of the anion of the monomer providing the repeating unit F2 include, but are not limited to, the anions shown below. In the following formula, A¹As before.

[ solution 57]

Examples of the anion of the monomer providing the repeating unit F3 include, but are not limited to, the anions shown below.

[ solution 58]

Examples of the sulfonium cation in the formulae (F2) to (F4) include the following cations, but are not limited thereto. In the following formula, Me is a methyl group, nBu is an n-butyl group, and tBu is a tert-butyl group.

[ chemical 59]

The repeating units F1 to F4 function as an acid generator. In this case, the base polymer also functions as an acid generator. When the base polymer containing the repeating units F1 to F4 is used, the additive acid generator described later may be contained or not contained.

The base polymer may contain repeating units derived from a monomer having a carbon-carbon double bond other than those described above, and may contain substituted acrylates derived from methyl methacrylate, methyl crotonate, dimethyl maleate, dimethyl itaconate, and the like; unsaturated carboxylic acids such as maleic acid, fumaric acid, and itaconic acid; norbornene, norbornene derivatives, tetracyclic [4.4.0.1^2,5.17^7,10]Cyclic olefins such as dodecene derivatives, unsaturated anhydrides such as itaconic anhydride, α -methylene-gamma-butyrolactone, and repeating units of monomers such as indene and acenaphthene.

In the aforementioned base polymer, the ideal content ratio of each repeating unit may fall within a range (mol%) shown below, for example, but is not limited thereto.

(I) 1 or 2 or more species of the repeating unit A fall within a range of 1 to 98 mol%, preferably 1 to 80 mol%, more preferably 10 to 70 mol%.

(II) 1 or more species of the repeating units B to E fall within a range of 2 to 99 mol%, preferably 2 to 80 mol%, more preferably 2 to 70 mol%.

(III) 1 or more of the repeating units F1 to F4 fall within a range of 0 to 50 mol%, preferably within a range of 0 to 30 mol%, more preferably within a range of 0 to 20 mol%.

(IV) 1 or more of the other repeating units fall within the range of 0 to 97 mol%, preferably 0 to 70 mol%, more preferably 0 to 50 mol%.

The weight average molecular weight (Mw) of the base polymer is preferably 1,000 to 500,000, more preferably 3,000 to 100,000. When Mw is within the above range, etching resistance is good, contrast before and after exposure can be ensured, and resolution is also good. In the present invention, Mw is a polystyrene-equivalent measured value obtained by Gel Permeation Chromatography (GPC) using Tetrahydrofuran (THF) or N, N-Dimethylformamide (DMF) as a solvent.

In addition, when the molecular weight distribution (Mw/Mn) of the base polymer is extremely wide, foreign substances may be observed on the pattern after exposure and the shape of the pattern may be deteriorated because of the presence of a polymer having a low molecular weight and a high molecular weight. Therefore, since the influence of Mw and Mw/Mn tends to be large as the pattern is made finer, the Mw/Mn of the base polymer is preferably 1.0 to 3.0, more preferably 1.0 to 2.5, in order to obtain a resist composition suitable for a fine pattern size. The aforementioned base polymers may be used alone in 1 kind or in combination of 2 or more kinds.

The method for producing the base polymer includes a step of supplying a monomer solution containing a monomer providing the repeating unit to a reaction vessel, and a step of carrying out a polymerization reaction in the reaction vessel.

Various monomers are dissolved in a solvent, and a polymerization initiator is added to the obtained monomer solution and heated to carry out polymerization. The solvents used in the polymerization include: toluene, benzene, THF, diethyl ether, dioxane, cyclohexane, cyclopentane, Methyl Ethyl Ketone (MEK), Propylene Glycol Monomethyl Ether Acetate (PGMEA), γ -butyrolactone (GBL), and the like. The polymerization initiator includes: 2,2' -Azobisisobutyronitrile (AIBN), 2' -azobis (2, 4-dimethylvaleronitrile), dimethyl-2, 2-azobis (2-methylpropionate), 1' -azobis (1-acetoxy-1-phenylethane), benzoyl peroxide, lauroyl peroxide and the like. The amount of the initiator added is preferably 0.01 to 25 mol% based on the total amount of the monomers to be polymerized. The reaction temperature is preferably 50 to 150 ℃, and more preferably 60 to 100 ℃. The reaction time is preferably 2 to 24 hours, and more preferably 2 to 12 hours from the viewpoint of production efficiency.

The polymerization initiator may be added to the monomer solution and then supplied to the reaction vessel, or an initiator solution different from the monomer solution may be prepared and supplied to the reaction vessel separately. Since there is a possibility that the polymerization reaction proceeds due to radicals generated from the initiator during the standby time and an ultra-high molecular weight is generated, it is preferable to prepare and add the monomer solution and the initiator solution separately from each other in view of quality control. The acid-labile group may be used in the form of being introduced into a monomer as it is, or may be protected or partially protected after polymerization. Further, for adjusting the molecular weight, a known chain transfer agent such as dodecyl mercaptan, 2-mercaptoethanol, or the like may be used in combination. In this case, the amount of the chain transfer agent added is preferably 0.01 to 20 mol% based on the total amount of the monomers to be polymerized.

When hydroxystyrene or hydroxyvinylnaphthalene is copolymerized, hydroxystyrene or hydroxyvinylnaphthalene and other monomers may be polymerized by heating in an organic solvent with the addition of a radical polymerization initiator, or acetoxystyrene or acetoxyvinylnaphthalene may be used, and after polymerization, acetoxy groups are deprotected by alkali hydrolysis to produce polyhydroxystyrene or hydroxypolyvinylnaphthalene.

As the base for the basic hydrolysis, ammonia, triethylamine and the like can be used. In addition, the reaction temperature is preferably-20 to 100 ℃, and more preferably 0 to 60 ℃. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

The amount of each monomer in the monomer solution may be appropriately set so as to be, for example, an ideal content ratio of the repeating unit.

The polymer obtained by the above-mentioned production method can be used to produce a final product from a reaction solution obtained by a polymerization reaction, or can be used as a final product from a powder obtained by a purification step such as reprecipitation in which a polymerization solution is added to a poor solvent to obtain a powder. Specific examples of the solvent used in this case include: ketones such as cyclohexanone and methyl-2-n-amyl ketone described in paragraphs [0144] to [0145] of Japanese patent laid-open No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ethers such as Propylene Glycol Monomethyl Ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, t-butyl acetate, t-butyl propionate, and propylene glycol mono-t-butyl ether acetate; lactones such as GBL; alcohols such as diacetone alcohol; high boiling point alcohol solvents such as diethylene glycol, propylene glycol, glycerin, 1, 4-butane diol, 1, 3-butane diol, and the like; and a mixed solvent thereof.

The concentration of the polymer in the polymer solution is preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass.

The reaction solution and the polymer solution are preferably filtered by a filter. By performing the filter filtration, foreign substances and gels which may cause defects can be removed, and the quality can be effectively stabilized.

The material of the filter used for the filter filtration may be: a fluorocarbon, cellulose, nylon, polyester, hydrocarbon filter, or the like, but the filtering step of the resist composition is preferably a filter made of fluorocarbon called teflon (registered trademark), hydrocarbon such as polyethylene or polypropylene, or nylon. The pore size of the filter can be appropriately selected according to the target degree of cleanliness, and is preferably 100nm or less, and more preferably 20nm or less. Further, these filters may be used alone in 1 kind, or a plurality of kinds may be used in combination. The filtration method may be to pass the solution only 1 time, but it is more preferable to circulate the solution and perform filtration a plurality of times. The filtration step may be performed in any order and number of times in the polymer production step, but it is preferable to filter the reaction solution after the polymerization reaction, the polymer solution, or both.

[ organic solvent ]

The organic solvent may be, for example: ketones such as cyclohexanone, cyclopentanone, methyl-2-n-amyl ketone, diacetone alcohol and the like; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, methyl lactate, ethyl lactate, n-butyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, t-butyl acetate, t-butyl propionate, propylene glycol mono-t-butyl ether acetate, methyl 2-hydroxyisobutyrate, isopropyl 2-hydroxyisobutyrate, isobutyl 2-hydroxyisobutyrate, and n-butyl 2-hydroxyisobutyrate; lactones such as GBL; and a mixed solvent thereof.

In the resist composition of the present invention, the content of the organic solvent is preferably 50 to 10,000 parts by mass, and more preferably 100 to 5,000 parts by mass, relative to 80 parts by mass of the base polymer. The organic solvent can be used alone in 1 or more than 2 mixed use.

[ acid generators ]

In the resist composition of the present invention, when the base polymer is not a polymer-bonded acid generator, an acid generator (hereinafter also referred to as an additive acid generator) is further contained. When the base polymer is a polymer-bonded acid generator, the additive acid generator may be contained or not contained.

Examples of the additive acid generator include compounds (photoacid generators) that generate an acid in response to active light or radiation. Specific examples of such photoacid generators include, for example, the compounds described in paragraphs [0122] to [0142] of Japanese patent application laid-open No. 2008-111103, and particularly preferable examples of the structures include the compounds described in paragraphs [0088] to [0092] of Japanese patent application laid-open No. 2014-1259, the compounds described in paragraphs [0015] to [0017] of Japanese patent application laid-open No. 2012-41320, and the compounds described in paragraphs [0015] to [0029] of Japanese patent application laid-open No. 2012-106986. The partially fluorinated sulfonic acid-generating photoacid generator described in the above publication is preferably used, particularly in ArF lithography, because the generated acid has an appropriate strength and diffusion length.

Examples of acids generated from the additive acid generator include: sulfonic acid, imide acid, methide acid, and like strong acids. The term strong acid as used herein refers to a compound having a degree of acidity sufficient to cause deprotection of acid labile groups of the base polymer. Among them, sulfonic acids fluorinated in the α -position are most commonly used, but when the acid-labile group is an acetal which is easily deprotected, it is not necessarily necessary to have a fluorination in the α -position.

The additive acid generator is preferably an acid generator represented by the following formula (AG1) or (AG 2).

[ solution 60]

In the formula (AG1), R¹⁰¹Is a C1-35 hydrocarbon group which may be a hydrogen atom, a fluorine atom or a heteroatom. R¹⁰²、R¹⁰³And R¹⁰⁴Each independently is a C1-20 hydrocarbon group which may contain a hetero atom. Furthermore, R¹⁰²、R¹⁰³And R¹⁰⁴Any 2 of them may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded.

R¹⁰¹The 1-valent hydrocarbon group represented may be any of linear, branched, and cyclic, and specific examples thereof include: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, cyclopentyl, hexyl, cyclohexyl, 3-cyclohexenyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl methyl, tricyclodecyl, tetracyclododecyl methyl, dicyclohexylmethyl, eicosyl, allyl, benzyl, diphenylmethyl, tetrahydrofuryl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, (2-methoxyethoxy) methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, tert-butyl, pentyl, neopentyl, cyclohexyl, 3-adamantyl, norbornyl, tricyclodecyl, tetracyclodecyl, tetracyclododecyl, dicyclohexylmethyl, eicosyl, allyl, 4-oxo-1-adamantyl, 3-oxocyclohexyl, and the like. In addition, some of the hydrogen atoms of these groups may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom or the like, or some of the carbon atoms of these groups may be interposedThe group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom and the like may contain a hydroxyl group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride, a halogenated alkyl group and the like as a result.

In the formula (AG2), R²⁰¹And R²⁰²Each independently is a C1-20 hydrocarbon group which may contain a hetero atom. R²⁰³Is a C1-20 2-valent hydrocarbon group which may contain a hetero atom. Furthermore, R²⁰¹、R²⁰²And R²⁰³Any 2 of them may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. L is^AIs a single bond, an ether bond, or a C1-20 2-valent hydrocarbon group which may contain a hetero atom.

In the formulae (AG1) and (AG2), X^a、X^b、X^CAnd X^dEach independently is a hydrogen atom, a fluorine atom or a trifluoromethyl group. k is a radical of¹And k²Each independently is an integer of 1 to 4.

Further, the acid generator represented by the formula (AG1) is preferably an acid generator represented by the following formula (AG 1'); the acid generator represented by the formula (AG2) is preferably an acid generator represented by the following formula (AG 2').

[ solution 61]

In the formulae (AG1') and (AG2'), R¹⁰²、R¹⁰³、R¹⁰⁴And L^AAs before. A. the³And A⁴Each independently is a hydrogen atom or a trifluoromethyl group. R¹⁰⁵Is a C1-35 hydrocarbon group which may contain a hetero atom. R²¹¹、R²¹²And R²¹³Each independently represents a hydrogen atom or a C1-20 hydrocarbon group which may contain a hetero atom. p and q are each independently an integer of 0 to 5. r is an integer of 0 to 4.

The additive acid generator is an acid generator represented by the formula (AG1') or (AG2'), preferably by A in the formula (AG1') or (AG2')³Or A⁴Acid generators that are trifluoromethyl, for example if in a line and space pattern, can form low LWR and acid-spreadThe control of the divergence length is improved, and in addition, if it is a hole pattern, a true circular, size control improved pattern can be formed.

Examples of the acid generator represented by the formula (AG1) include, but are not limited to, the following acid generators. In the following formula, A³Me is methyl, Ac is acetyl and Ph is phenyl, as before.

[ solution 62]

[ solution 63]

[ solution 64]

[ solution 65]

[ solution 66]

[ solution 67]

Specific examples of the acid generator represented by the formula (AG2) are shown below, but not limited thereto. In the following formula, A⁴Me is methyl, as before.

[ solution 68]

[ solution 69]

When the resist composition of the present invention contains the additive acid generator, the content thereof is preferably 0.5 to 30 parts by mass, more preferably 1 to 20 parts by mass, relative to 80 parts by mass of the base polymer. The base polymer contains repeating units F1 to F4 and/or contains an additive acid generator, whereby the resist composition of the present invention can function as a chemically amplified resist composition. The additive acid generators may be used alone in 1 kind or in combination of 2 or more kinds.

[ quenching agent ]

The resist composition of the present invention may further contain a quencher (acid diffusion controlling agent). In addition, the quencher in the present invention refers to a component for preventing diffusion thereof toward an unexposed portion by trapping an acid generated from a photoacid generator in a resist composition, and for forming a desired pattern.

Examples of the quencher include primary, secondary or tertiary amine compounds described in paragraphs [0146] to [0164] of Japanese patent application laid-open No. 2008-111103, particularly amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group and a sulfonic ester bond, and compounds having a carbamate group described in Japanese patent application laid-open No. 3790649.

The aforementioned quencher may also use an onium salt represented by the following formula (xa) or (xb).

[ solution 70]

In the formula (xa), R^q1A 1-valent hydrocarbon group of 1 to 40 carbon atoms which may contain a heteroatom, wherein the hydrogen atoms bonded to the carbon atoms at the α -position and the β -position of the sulfo group are not substituted by a fluorine atom or a fluoroalkyl group^q2Is a C1-40 hydrocarbon group which may be a hydrogen atom or a heteroatom.

R^q1The 1-valent hydrocarbon group represented by (a): methyl, ethylPropyl, isopropyl, n-butyl, sec-butyl, tert-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, tricyclo [5.2.1.0^2,6]Decyl, adamantyl, phenyl, naphthyl, anthracenyl, and the like. Further, some of the hydrogen atoms of these groups may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, or a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or the like, which may be interposed between carbon-carbon atoms of these groups, and as a result, a hydroxyl group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride, a halogenated alkyl group, or the like may be contained.

R^q2Specific examples of the 1-valent hydrocarbon group include R^q1Specific examples of the substituent include a fluorine-containing alkyl group such as a trifluoromethyl group and a trifluoroethyl group, and a fluorine-containing aryl group such as a pentafluorophenyl group and a 4-trifluoromethylphenyl group.

In the formula (xa), specific structures of the anion include, but are not limited to, the structures shown below.

[ solution 71]

[ chemical formula 72]

Specific structures of the anion in the formula (xb) include, but are not limited to, the structures shown below.

[ solution 73]

In the formulae (xa) and (xb), Mq⁺Is of the formula (c1), (c2) or(c3) Onium cation of the formula.

[ chemical formula 74]

In the formulae (c1) to (c3), R³⁰¹、R³⁰²、R³⁰³、R³⁰⁴、R³⁰⁵、R³⁰⁶、R³⁰⁷、R³⁰⁸And R³⁰⁹Each independently is a C1-40 hydrocarbon group which may contain a hetero atom. Furthermore, R³⁰¹And R³⁰²Or may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. And R is³⁰⁶And R³⁰⁷Or may be bonded to each other and form a ring together with the nitrogen atom to which they are bonded. R³⁰¹～R³⁰⁹Specific examples of the 1-valent hydrocarbon group represented by (X) are R in the formula (xa)^q1The groups shown are the same as the 1-valent hydrocarbon groups.

In the formulae (xa) and (xb), the cation moiety (Mq)⁺) Specific examples thereof include, but are not limited to, the following cations. In the following formula, Me is a methyl group.

[ solution 75]

[ 76]

Specific examples of the onium salt represented by the formula (xa) or (xb) include any combination of the aforementioned anion and cation. In addition, these onium salts can be easily prepared by ion exchange reaction using a known organic chemical method. For the ion exchange reaction, for example, refer to Japanese patent application laid-open No. 2007-145797.

The onium salt represented by the formula (xa) or (xb) functions as a quencher in the resist composition of the present invention. This is because each counter anion of the aforementioned onium salt is a conjugate base of a weak acid. As used herein, a weak acid refers to an acid that exhibits a degree of acidity that does not deprotect the acid labile groups of the acid labile group-containing units used in the base polymer. The onium salt represented by the formula (xa) or (xb) functions as a quencher when used together with an onium salt type photoacid generator having a conjugate base of a strong acid such as a sulfonic acid fluorinated in the α -position as a counter anion. That is, when an onium salt that generates a strong acid such as an α -fluorinated sulfonic acid and an onium salt that generates a weak acid such as a non-fluorine-substituted sulfonic acid or carboxylic acid are used in combination, the strong acid generated from the photoacid generator by irradiation with high-energy rays collides with an unreacted onium salt having a weak acid anion, and the weak acid is released through salt exchange, thereby generating an onium salt having a strong acid anion. In this process, the strong acid is exchanged for a weak acid with a lower catalyst capacity, and thus the acid is apparently deactivated to allow control of the acid diffusion.

Here, when the photoacid generator which generates a strong acid is an onium salt, the strong acid generated by irradiation with a high-energy ray can be exchanged with a weak acid as described above, but it is considered that the weak acid generated by irradiation with a high-energy ray is less likely to collide with an unreacted onium salt which generates a strong acid, thereby performing salt exchange. This is due to the phenomenon that onium cations readily form ion pairs with the anions of stronger acids.

Further, as the onium salt type quencher of a weak acid, a compound represented by the following formula (xc) can be used.

[ solution 77]

In the formula (xc), R⁴⁰¹And R⁴⁰²Independently represents a C1-12 alkyl group, a nitro group, a C1-12 alkoxy group, a C2-12 acyl group or a C2-12 acyloxy group. x and y are each independently an integer of 0 to 4.

The compound represented by the formula (xc) includes, but is not limited to, the compounds shown below.

[ solution 78]

In the resist composition of the present invention, the content of the quencher is 0 to 100 parts by mass, and preferably 0.001 to 50 parts by mass, if contained, relative to 80 parts by mass of the base polymer. The aforementioned quenchers may be used singly or in combination of 1 or more than 2.

[ other ingredients ]

In addition to the above components, the resist composition of the present invention may be formulated by appropriately combining a surfactant, a dissolution controlling agent, an acetylene alcohol, a water repellency improving agent, and the like according to the purpose. As the surfactant, those described in paragraphs [0165] to [0166] of Japanese patent application laid-open No. 2008-111103 can be used. The dissolution control agent can be the one described in paragraphs [0155] to [0178] of Japanese patent application laid-open No. 2008-122932. The acetylene alcohols described in paragraphs [0179] to [0182] of Japanese patent application laid-open No. 2008-122932 can be used.

The content of the dissolution controlling agent is preferably 0 to 50 parts by mass, and more preferably 0 to 40 parts by mass, relative to 80 parts by mass of the base polymer. The contents of the surfactant and the acetylene alcohol may be appropriately selected according to the purpose of blending.

The resist composition of the present invention may contain a water repellency improver for improving the water repellency of the resist surface after spin coating. The water repellency improver can be used in immersion lithography without using a top coat (top coat). Such a water repellency improver is preferably a water repellency improver having a specific structure and having a 1,1,1,3,3, 3-hexafluoro-2-propanol residue, and more preferably the water repellency improvers described in japanese patent application laid-open nos. 2007 & 297590, 2008 & 111103, 2008 & 122932, 2012 & 128067, and 2013 & 57836.

The water repellency improver may specifically be a polymer for improving water repellency, and is preferably a polymer composed of 1 fluorine atom-containing unit, a copolymer composed of 2 or more fluorine atom-containing units, or a copolymer composed of a fluorine atom-containing unit and a unit containing no fluorine atom.

Examples of the fluorine atom-containing unit and other units include, but are not limited to, the following units. In the following formula, R^BIs a hydrogen atom or a methyl group.

[ solution 79]

[ solution 80]

[ solution 81]

[ solution 82]

[ solution 83]

[ solution 84]

[ solution 85]

[ solution 86]

The aforementioned water repellency improver needs to be dissolved in an alkaline aqueous solution of a developer. The water repellency improver having a 1,1,1,3,3, 3-hexafluoro-2-propanol residue has good solubility in a developer. The water repellency improver contains a polymer compound having a repeating unit of an amino group or an amine salt, and has a high effect of preventing evaporation of an acid in PEB, and preventing poor opening of a hole pattern and bridging between a line pattern and a pitch pattern after development. The content of the water repellency improver is preferably 0 to 20 parts by mass, more preferably 0.1 to 20 parts by mass, and still more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of the base polymer. The water repellency improver may be used alone in 1 kind or in combination of 2 or more kinds.

[ Pattern Forming method ]

The pattern forming method of the present invention includes a step of forming a resist film on a substrate using the resist composition, a step of exposing the resist film to high-energy radiation, and a step of developing the exposed resist film with a developer to obtain a pattern. Several additional steps may be added as necessary.

For example, the resist composition of the present invention is applied to a substrate (Si, SiO) for integrated circuit fabrication by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, blade coating, and the like₂SiN, SiON, TiN, WSi, BPSG, SOG, silicon-containing antireflection film, or organic hydrocarbon film-containing multilayer film) or a substrate for mask circuit fabrication (Cr, CrO, CrON, MoSi)₂、SiO₂Etc.) so that the coating film thickness is 0.01 to 2 μm. The pre-baking is carried out on a heating plate, preferably at 60-150 ℃ for 10-30 minutes, more preferably at 80-120 ℃ for 30-20 minutes.

Then, the resist film is exposed to high-energy radiation. The high-energy radiation includes: ultraviolet rays, far ultraviolet rays, EB, X rays, excimer laser, gamma rays, synchrotron radiation, EUV, soft X rays, and the like. When ultraviolet rays, far ultraviolet rays, X-rays, excimer laser, gamma rays, synchrotron radiation, EUV, and soft X-rays are used as the high-energy rays, a mask for forming a target pattern is used, and the exposure amount is preferably about 1 to 200mJ/cm²More preferably, it is about 10 to 100mJ/cm²The irradiation is performed in the manner of (1). When EB is used as the high-energy ray, the exposure amount is preferably about 0.1～100μC/cm²More preferably about 0.5 to 50 μ C/cm²The writing is performed directly or using a mask for forming a target pattern. The resist composition of the present invention is particularly suitable for fine patterning by KrF excimer laser, ArF excimer laser, EB, EUV, soft X-ray, γ -ray, synchrotron radiation, and the like among high-energy rays.

In addition to the usual exposure method, the exposure may be performed by an immersion method in which a liquid having a refractive index of 1.0 or more, such as water, is interposed between the resist film and the projection lens. In this case, a water-insoluble protective film may be used.

The water-insoluble protective films are used for preventing the elution from the resist film and for improving the water-slipping property of the film surface, and are roughly classified into 2 types. The resist film is one which is an organic solvent-peeling type requiring peeling with an organic solvent that does not dissolve the resist film before the alkali aqueous solution development, and the other one which is an alkali aqueous solution-soluble type soluble in an alkali developing solution and removing the resist film-soluble portion and the protective film. The latter is particularly preferably a material based on a polymer having a 1,1,1,3,3, 3-hexafluoro-2-propanol residue, which is insoluble in water and soluble in an alkali developing solution, and dissolved in an alcohol solvent having 4 or more carbon atoms, an ether solvent having 8 to 12 carbon atoms, or a mixed solvent thereof. The surfactant insoluble in water and soluble in an alkali developer may be dissolved in an alcohol solvent having 4 or more carbon atoms, an ether solvent having 8 to 12 carbon atoms, or a mixed solvent thereof.

After exposure, PEB may be applied to the hot plate, preferably at 60 to 150 ℃ for 10 seconds to 30 minutes, more preferably at 80 to 120 ℃ for 30 seconds to 20 minutes.

Development is performed after exposure or after PEB. The development is carried out, for example, with a developer of an aqueous alkali solution such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH) in an amount of 0.1 to 10% by mass, preferably 2 to 5% by mass, preferably 3 seconds to 3 minutes, more preferably 5 seconds to 2 minutes, by a conventional method such as a dip (dip) method, a dip (paddle) method, or a spray (spray) method, whereby the portion irradiated with light is dissolved in the developer, and the unexposed portion is not dissolved, thereby forming a desired positive pattern on the substrate.

Negative development to obtain a negative pattern by development with an organic solvent can also be carried out using the resist composition of the present invention. The developing solution used in this case includes: 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butenyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isoamyl lactate, 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, Methyl phenylacetate, benzyl formate, phenethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, and the like. These organic solvents can be used alone in 1 or more than 2.

After the development step, rinsing may be performed by a common method such as a dipping method, or a spraying method using water, preferably for 3 seconds to 3 minutes, more preferably for 5 seconds to 2 minutes.

The hole pattern and the groove pattern after development may be shrunk by heat flow, RELACS technique, DSA technique, or the like. The hole pattern is coated with a shrinking agent, and the shrinking agent is crosslinked on the surface of the resist by diffusion of an acid catalyst from the resist layer during baking, so that the shrinking agent is attached to the side wall of the hole pattern. The baking temperature is preferably 70-180 ℃, more preferably 80-170 ℃, and the baking time is 10-300 seconds. Finally, removing the redundant shrinking agent to reduce the hole pattern.