JP2012229198A - Salt, resist composition, and method for producing resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist composition capable of producing a resist pattern in an excellent focus margin (DOF).SOLUTION: A salt is represented to by a formula (I). In the formula, R, L-CH-, Y are specific groups.

Description

  The present invention relates to a salt for an acid generator used for microfabrication of a semiconductor, a resist composition, and a method for producing a resist pattern.

Patent Document 1 describes a resist composition containing a salt represented by the following formula as a salt for an acid generator.

JP 2010-61018 A

  Conventionally known resist compositions containing the above acid generators may not always have a satisfactory focus margin (DOF) during the production of the resist pattern.

［式（Ｉ）中、
Ｒ^１及びＲ^２は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^１は、２価の炭素数１〜１７の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
Ｙは、置換基を有していてもよい炭素数１〜１８の脂肪族炭化水素基又は置換基を有していてもよい炭素数３〜１８の脂環式炭化水素基を表し、該脂肪族炭化水素基及び該脂環式炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−、−ＳＯ_２−又は−ＣＯ−で置き換わっていてもよい。
ｍ及びｎは、それぞれ独立に、１又は２を表す。
Ｒ^３及びＲ^４は、それぞれ独立に、水素原子又は炭素数１〜６のアルキル基を表す。
ｍが２であるとき、複数存在するＲ^３は、互いに同じでも異なっていてもよい。
ｎが２であるとき、複数存在するＲ^４は、互いに同じでも異なっていてもよい。
Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８及びＲ^９は、それぞれ独立に、水素原子、ヒドロキシ基又は炭素数１〜１２の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。］
〔２〕ｍ及びｎが２であり、かつ、Ｒ^３及びＲ^４が水素原子である前記〔１〕記載の塩。
〔３〕Ｌ^１が、＊−ＣＯ−Ｏ−（ＣＨ_２）_ｎ−（＊は、−Ｃ（Ｒ^４）（Ｒ^５）−の炭素原子との結合手を表し、ｎは０又は１を表す。）である前記〔１〕又は前記〔２〕のいずれかに記載の塩。
〔４〕前記〔１〕〜〔３〕のいずれかに記載の塩を含有する酸発生剤。
〔５〕前記〔４〕記載の酸発生剤と樹脂とを含み、該樹脂は酸に不安定な基を有し、かつアルカリ水溶液に不溶又は難溶な樹脂であり、酸の作用によりアルカリ水溶液に溶解し得る樹脂であるレジスト組成物。
〔６〕さらに溶剤を含む前記〔５〕記載のレジスト組成物。
〔７〕さらに塩基性化合物を含む前記〔５〕又は〔６〕記載のレジスト組成物。
〔８〕（１）前記〔５〕〜〔７〕のいずれかに記載のレジスト組成物を基板上に塗布する工程、
（２）塗布後の組成物を乾燥させて組成物層を形成する工程、
（３）組成物層に露光機を用いて露光する工程、
（４）露光後の組成物層を加熱する工程、及び
（５）加熱後の組成物層を現像する工程を含むレジストパターンの製造方法。 The present invention includes the following inventions.
[1] A salt represented by the formula (I).

[In the formula (I),
R ¹ and R ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. .
Y represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent; —CH ₂ — contained in the aromatic hydrocarbon group and the alicyclic hydrocarbon group may be replaced by —O—, —SO ₂ — or —CO—.
m and n each independently represents 1 or 2.
R ³ and R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
When m is 2, a plurality of R ³ may be the same as or different from each other.
When n is 2, a plurality of R ⁴ may be the same as or different from each other.
R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represents a hydrogen atom, a hydroxy group or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group is , -O- or -CO-. ]
[2] The salt according to [1], wherein m and n are 2, and R ³ and R ⁴ are hydrogen atoms.
[3] L ¹ represents * —CO—O— (CH ₂ ) _n — (* represents a bond with a carbon atom of —C (R ⁴ ) (R ⁵ ) —, and n represents 0 or 1 The salt according to either [1] or [2] above.
[4] An acid generator containing the salt according to any one of [1] to [3].
[5] The acid generator according to [4] and a resin, wherein the resin has an acid labile group and is insoluble or hardly soluble in an alkaline aqueous solution. A resist composition, which is a resin that can be dissolved in water.
[6] The resist composition according to [5], further including a solvent.
[7] The resist composition according to [5] or [6], further including a basic compound.
[8] (1) A step of applying the resist composition according to any one of [5] to [7] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer using an exposure machine;
(4) A method for producing a resist pattern, comprising a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.

  If a resist composition containing the salt of the present invention is used as an acid generator, a resist pattern can be produced with an excellent focus margin (DOF).

［式（Ｉ）中、
Ｒ^１及びＲ^２は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^１は、２価の炭素数１〜１７の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
Ｙは、置換基を有していてもよい炭素数１〜１８の脂肪族炭化水素基又は置換基を有していてもよい炭素数３〜１８の脂環式炭化水素基を表し、該脂肪族炭化水素基及び該脂環式炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−、−ＳＯ_２−又は−ＣＯ−で置き換わっていてもよい。
ｍ及びｎは、それぞれ独立に、１又は２を表す。
Ｒ^３及びＲ^４は、それぞれ独立に、水素原子又は炭素数１〜６のアルキル基を表す。
ｍが２であるとき、複数存在するＲ^３は、互いに同じでも異なっていてもよい。
ｎが２であるとき、複数存在するＲ^４は、互いに同じでも異なっていてもよい。
Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８及びＲ^９は、それぞれ独立に、水素原子、ヒドロキシ基又は炭素数１〜１２の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。］
以下の説明において、塩（Ｉ）のうち、正電荷を有する側を「有機カチオン」と、負電荷を有する側を「有機アニオン」と、それぞれ称することがある。 <Salt>
The salt of the present invention is a salt represented by the formula (I) (hereinafter sometimes referred to as “salt (I)”).

[In the formula (I),
R ¹ and R ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. .
Y represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent; —CH ₂ — contained in the aromatic hydrocarbon group and the alicyclic hydrocarbon group may be replaced by —O—, —SO ₂ — or —CO—.
m and n each independently represents 1 or 2.
R ³ and R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
When m is 2, a plurality of R ³ may be the same as or different from each other.
When n is 2, a plurality of R ⁴ may be the same as or different from each other.
R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represents a hydrogen atom, a hydroxy group or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group is , -O- or -CO-. ]
In the following description, in the salt (I), the side having a positive charge may be referred to as an “organic cation”, and the side having a negative charge may be referred to as an “organic anion”.

［式（Ｉ−Ａ）中、
Ｒ^１及びＲ^２は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^１は、２価の炭素数１〜１７の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
Ｙは、置換基を有していてもよい炭素数１〜１８の脂肪族炭化水素基又は置換基を有していてもよい炭素数３〜１８の脂環式炭化水素基を表し、該脂肪族炭化水素基及び該脂環式炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−、−ＳＯ_２−又は−ＣＯ−で置き換わっていてもよい。］ <Organic anion>
The organic anion of the salt represented by the formula (I) is a sulfonate anion represented by the formula (IA).

[In the formula (IA),
R ¹ and R ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. .
Y represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent; —CH ₂ — contained in the aromatic hydrocarbon group and the alicyclic hydrocarbon group may be replaced by —O—, —SO ₂ — or —CO—. ]

Examples of the perfluoroalkyl group for R ¹ and R ² include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, and a perfluoropentyl group. And a perfluorohexyl group.
As an acid generator used in the resist composition of the present invention, R ¹ and R ² are each independently preferably a trifluoromethyl group or a salt (I) which is a fluorine atom, and both are salts (I) which are both a fluorine atom. Is more preferable.

Examples of the divalent saturated hydrocarbon group for L ¹ include a linear alkanediyl group, a branched alkanediyl group, a monocyclic or polycyclic divalent alicyclic hydrocarbon group, and these groups Two or more of them may be combined.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1 , 6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group , Dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1, Linear alkanediyl groups such as 17-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group and propane-2,2-diyl group;
An alkyl group (particularly an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group); For example, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl A branched alkanediyl group such as a 2-methylbutane-1,4-diyl group;
Cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,2-diyl group, 1-methylcyclohexane-1,2-diyl group, cyclohexane-1,4-diyl group, cyclo A monocyclic divalent alicyclic hydrocarbon group which is a cycloalkanediyl group such as an octane-1,2-diyl group or a cyclooctane-1,5-diyl group;
Norbornane-2,3-diyl group, norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,2-diyl group, adamantane-1,5-diyl group, adamantane-2,6 -Polycyclic bivalent alicyclic hydrocarbon groups, such as a diyl group, etc. are mentioned.
Further, any one hydrogen atom in a monovalent alicyclic hydrocarbon described later may be used as a bond.

Examples of the group in which —CH ₂ — in the divalent saturated hydrocarbon group of L ¹ is replaced by —O— or —CO— include formula (b1-1) to formula (b1-6). The formula (b1-1) to the formula (b1-6) are described in accordance with the formula (IA) on the left and right sides, bonded to C (R ¹ ) (R ² )-on the left side, and on the right side. Combines with -Y. The same applies to specific examples of the following formulas (b1-1) to (b1-6).

式（ｂ１−１）〜式（ｂ１−６）中、
Ｌ^b2は、単結合又は炭素数１〜１５の２価の飽和炭化水素基を表す。
Ｌ^b3は、単結合又は炭素数１〜１２の２価の飽和炭化水素基を表す。
Ｌ^b4は、炭素数１〜１３の２価の飽和炭化水素基を表す。
Ｌ^b5は、炭素数１〜１５の２価の飽和炭化水素基を表す。
Ｌ^b6及びＬ^b7は、それぞれ独立に、炭素数１〜１５の２価の飽和炭化水素基を表す。
Ｌ^b8は、炭素数１〜１４の２価の飽和炭化水素基を表す。
Ｌ^b9及びＬ^b10は、それぞれ独立に、炭素数１〜１１の２価の飽和炭化水素基を表す。
中でも、Ｌ¹は、好ましくは式（ｂ１−１）〜式（ｂ１−４）のいずれか、より好ましくは式（ｂ１−１）又は式（ｂ１−２）、さらに好ましくは式（ｂ１−１）で表される２価の基であり、特に、Ｌ^b2が単結合又は−ＣＨ_２−である式（ｂ１−１）で表される２価の基が好ましい。

In formula (b1-1) to formula (b1-6),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b4 represents a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.
L ^b5 represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b6 and L ^b7 each independently represent a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b8 represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms.
L ^b9 and L ^b10 each independently represent a divalent saturated hydrocarbon group having 1 to 11 carbon atoms.
Among them, L ¹ is preferably any one of formula (b1-1) to formula (b1-4), more preferably formula (b1-1) or formula (b1-2), and still more preferably formula (b1-1). In particular, a divalent group represented by the formula (b1-1) in which L ^b2 is a single bond or —CH ₂ — is preferable.

Examples of the divalent group represented by the formula (b1-1) include the following.

Examples of the divalent group represented by the formula (b1-2) include the following.

Examples of the divalent group represented by the formula (b1-3) include the following.

Examples of the divalent group represented by the formula (b1-4) include the following.

Examples of the divalent group represented by the formula (b1-5) include the following.

Examples of the divalent group represented by the formula (b1-6) include the following.

Examples of the aliphatic hydrocarbon group for Y include a methyl group, an ethyl group, a 1-methylethyl group (isopropyl group), a 1,1-dimethylethyl group (tert-butyl group), a 2,2-dimethylethyl group, Propyl group, 1-methylpropyl group, 2,2-dimethylpropyl group, 1-ethylpropyl group, butyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-propylbutyl group, pentyl group, 1-methylpentyl group, hexyl group, 1,4-dimethylhexyl group, heptyl group, 1-methylheptyl group, octyl group, methyloctyl group, methylnonyl group, 2-ethylhexyl group, nonyl group, decyl group, undecyl group, Examples include linear or branched alkyl groups such as dodecyl group. Especially, a C1-C6 alkyl group is preferable.
Examples of the alicyclic hydrocarbon group for Y include groups represented by the following formulas (Y1) to (Y11).
Examples of the group in which —CH ₂ — in the aliphatic hydrocarbon group and the alicyclic hydrocarbon group is replaced by —O—, —SO ₂ — or —CO— include, for example, —CH ₂ — contained in the alkyl group described above. Group in which is replaced by —O— or —CO—, groups represented by the following formulas (Y12) to (Y26), and the like.

  Especially, it is preferably a group represented by any one of formulas (Y1) to (Y19), and more preferably represented by formula (Y11), formula (Y14), formula (Y15), and formula (Y19). And more preferably a group represented by formula (Y11) or formula (Y14).

Examples of the substituent of the aliphatic hydrocarbon group and alicyclic hydrocarbon group in Y include a halogen atom (excluding a fluorine atom), a hydroxy group, an oxo group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, hydroxy Group-containing C1-C12 aliphatic hydrocarbon group, C3-C36 alicyclic hydrocarbon group, C1-C12 alkoxy group, C6-C18 aromatic hydrocarbon group, carbon number An aralkyl group having 7 to 21 carbon atoms, an acyl group having 2 to 4 carbon atoms, a glycidyloxy group, or a — (CH ₂ ) _m —O—CO— ^Ra group (wherein R ^a is an aliphatic group having 1 to 36 carbon atoms) A hydrocarbon group, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, where m represents an integer of 0 to 4). In addition, the aliphatic hydrocarbon group, the alicyclic hydrocarbon group, the aromatic hydrocarbon group, the aralkyl group, and the like, which are the substituents of Y, may further have a substituent. Examples of the substituent here include an alkyl group, a halogen atom (excluding a fluorine atom), a hydroxy group, an oxo group, a glycidyloxy group, a cyano group, and a carboxyl group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the hydroxy group-containing aliphatic hydrocarbon group include a hydroxymethyl group and a hydroxyethyl group.
Examples of the alkoxy group include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, n-pentoxy group, n-hexoxy group and the like.
Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl Groups, phenanthryl groups, 2,6-diethylphenyl groups, aryl groups such as 2-methyl-6-ethylphenyl, and the like.
Examples of the aralkyl group include benzyl group, phenethyl group, phenylpropyl group, trityl group, naphthylmethyl group, naphthylethyl group and the like.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.

Examples of Y, which is an alicyclic hydrocarbon group substituted with an aliphatic hydrocarbon group, include the following.

Examples of Y that is an alicyclic hydrocarbon group substituted with a hydroxy group or a hydroxy group-containing aliphatic hydrocarbon group include the following.

Examples of Y, which is an alicyclic hydrocarbon group substituted with an aromatic hydrocarbon group, include the following.

Examples of Y that is an alicyclic hydrocarbon group substituted by ^a — (CH ₂ ) _m —O—CO—R ^a group include the following.

When Y is an aliphatic hydrocarbon group and L ¹ is a divalent aliphatic hydrocarbon group having 1 to 17 carbon atoms, the divalent aliphatic hydrocarbon group bonded to Y is constituted. The methylene group is preferably replaced with an oxygen atom or a carbonyl group. In this case, the methylene group constituting the aliphatic hydrocarbon group for Y is not replaced with an oxygen atom or a carbonyl group.

  Y is preferably an adamantyl group which may have a substituent (for example, a hydroxy group, a hydroxyalkyl group, an oxo group, etc.), more preferably an adamantyl group or an oxoadamantyl group having a hydroxy group, a hydroxyalkyl group. It is.

Examples of the sulfonate anion include formula (b1-1-1), formula (b1-1-2), formula (b1-1-3), formula (b1-1-4), and formula (b1-1-5). , Formula (b1-1-6), Formula (b1-1-7), Formula (b1-1-8), and Formula (b1-1-9) [Hereinafter, “Formula (b1-1-1) to Formula” (B1-1-9) ”. ] The sulfonate anion represented by either of these is preferable. R ⁱ² and R ⁱ³ are each independently the same as those exemplified as the substituent that the alicyclic hydrocarbon group represented by Y may have, and an alkyl group having 1 to 4 carbon atoms. And a hydroxy group are preferable, and a methyl group and a hydroxy group are more preferable.

Fatty acid substituted with sulfonate anion or aliphatic hydrocarbon group containing Y which is an aliphatic hydrocarbon group or an unsubstituted alicyclic hydrocarbon group and a divalent group represented by formula (b1-1) Examples of the sulfonate anion containing Y which is a cyclic hydrocarbon group and the divalent group represented by the formula (b1-1) include the following.

L ¹ is a group represented by the formula (b1-1), Y is _{- (CH 2) m -O-} CO-R a sulfonic acid is an alicyclic hydrocarbon group having a group represented by the group Examples of the anion include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-1) and Y is an alicyclic hydrocarbon group having a hydroxy group include the following.

As the sulfonate anion, L ¹ is a group represented by the formula (b1-1), and Y is an alicyclic hydrocarbon group having an aromatic hydrocarbon group or an alicyclic hydrocarbon group having an aralkyl group. For example, the following may be mentioned.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-1) and Y is a cyclic ether group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-1) and Y is the lactone ring group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-1) and Y is a cyclic ketone group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-1) and Y is a sultone ring group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-2) and Y is an aliphatic hydrocarbon group or an unsubstituted alicyclic hydrocarbon group include the following. .

A sulfonate anion in which L ¹ is a group represented by the formula (b1-2) and Y is an alicyclic hydrocarbon group having a group represented by — (CH ₂ ) _j2 —O—CO—R ^i1. For example, the following may be mentioned.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-2) and Y is an alicyclic hydrocarbon group having a hydroxy group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-2) and Y is an alicyclic hydrocarbon group having an aromatic hydrocarbon group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-2) and Y is a cyclic ether group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-2) and Y is a lactone ring group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-2) and Y is a cyclic ketone group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-2) and Y is a sultone ring group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-3) and Y is an aliphatic hydrocarbon group or an unsubstituted alicyclic hydrocarbon group include the following. It is done.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-3) and Y is an alicyclic hydrocarbon group having an alkoxy group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-3) and Y is an alicyclic hydrocarbon group having a hydroxy group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-3) and Y is a cyclic ketone group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-4) and Y is an unsubstituted alicyclic hydrocarbon group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-4) and Y is an alicyclic hydrocarbon group having an alkoxy group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-4) and Y is an alicyclic hydrocarbon group having a hydroxy group include the following.

Examples of the sulfonate anion in which L ¹ is a group represented by the formula (b1-4) and Y is a cyclic ketone group include the following.

Among the sulfonate anions, more preferred sulfonate anions are shown below.

［式（Ｉ−Ｂ）中、
Ｒ^３及びＲ^４は、それぞれ独立に、水素原子又は炭素数１〜６のアルキル基を表す。
ｍ及びｎは、それぞれ独立に、１又は２を表す。
ｍが２であるとき、複数存在するＲ^３は、互いに同じでも異なっていてもよい。
ｎが２であるとき、複数存在するＲ^４は、互いに同じでも異なっていてもよい。
Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８及びＲ^９は、それぞれ独立に、水素原子、ヒドロキシ基又は炭素数１〜１２の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。］ <Organic cation>
The organic cation of the salt represented by the formula (I) is represented by the formula (IB).

[In the formula (IB),
R ³ and R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
m and n each independently represents 1 or 2.
When m is 2, a plurality of R ³ may be the same as or different from each other.
When n is 2, a plurality of R ⁴ may be the same as or different from each other.
R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represents a hydrogen atom, a hydroxy group or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group is , -O- or -CO-. ]

Examples of the alkyl group for R ³ and R ⁴ are the same as those described above.
Examples of the hydrocarbon group for R ^{5 to} R ⁹ include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and combinations thereof.
Examples of the alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, and a cyclooctyl group.
Examples of the aromatic hydrocarbon group include those similar to the above.
Examples of the combination group include an aralkyl group, such as a benzyl group and a phenethyl group.
Examples of the group in which —CH ₂ — contained in the hydrocarbon group is replaced by —O— or —CO— include a methoxy group, an ethoxy group, a butoxy group, an acetyl group, a methoxycarbonyl group, a methylcarbonyloxy group, and a butoxycarbonyloxy group. Group, phenylcarbonyloxy group and the like.

In formula (IB), in the ring containing S, m and n are 2, and R ³ and R ⁴ are each preferably a ring represented by the following.

Examples of the organic cation include the following cations.

  Examples of the salt (I) include salts composed of a sulfonate anion and an organic cation described in Tables 1 and 2 below.

Of these, the salts shown below are preferred.

（式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８、Ｒ^９、Ｌ^１、ｍ、ｎ及びＹは、それぞれ前記と同義である。）
触媒としては、二安息香酸銅（ＩＩ）等が挙げられる。
溶剤としては、モノクロロベンゼン等が挙げられる。
式（Ｉ−ａ）で表される塩としては、例えば、以下で表される化合物などが挙げられる。

The salt represented by the formula (I) is obtained by, for example, reacting the salt represented by the formula (Ia) and the salt represented by the formula (Ib) in a solvent in the presence of a catalyst. Can be manufactured.

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , L ¹ , m, n and Y are as defined above).
Examples of the catalyst include copper (II) dibenzoate.
Examples of the solvent include monochlorobenzene.
Examples of the salt represented by the formula (Ia) include compounds represented by the following.

The compound represented by the formula (Ib) can be produced by reducing the compound represented by the formula (Ic) in a solvent.
Examples of the reducing agent include sodium borohydride.
Examples of the solvent include acetonitrile / ion exchange water.

Examples of the compound represented by the formula (Ic) include compounds represented by the following.

<Acid generator>
The acid generator of the present invention contains a salt (I). When the salt (I) is used as an acid generator, it may be used alone or in combination.
In addition, the acid generator of the present invention further includes a salt known as an acid generator other than the salt (I) (for example, an organic cation contained in the salt (I) and a known anion (sulfone contained in the salt (I)). A salt composed of an anion other than the acid anion), a sulfonate anion contained in the salt (I), and a known cation (such as a salt composed of a cation other than the organic cation contained in the salt (I)). Hereinafter, salts other than the salt (I) contained in the acid generator may be referred to as “acid generator (B)”. The acid generator (B) may be used alone or in combination of two or more.

  As an acid generator (B) used together with salt (I), the compound which consists of a sulfonate anion and a sulfonium cation contained in salt (I) is mentioned. For example, what is represented by Formula (B1-1)-Formula (B1-20) is mentioned. Among these, those containing a triarylsulfonium cation are preferable, and a triphenylsulfonium cation and a tolylsulfonium cation are more preferable. In particular, Formula (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-6), Formula (B1-7), Formula (B1-11), Formula (B1-12) Further preferred are salts selected from formula (B1-13) and formula (B1-14).

In the acid generator, the content of the salt (I) is 5 parts by mass or more, preferably 10 parts by mass or more (more preferably 30 parts by mass or more), 100 parts by mass with respect to 100 parts by mass of the total amount of the acid generator. Part or less, preferably 95 parts by weight or less (more preferably 90 parts by weight or less).
The ratio (mass) of the content of the salt (I) and the acid generator (B) is, for example, 5:95 to 100: 0, preferably 5:95 to 95: 5, and more preferably 10:90. It is -90: 10, More preferably, it is 15: 85-85: 15, More preferably, it is 30: 70-70: 30.

<Resist composition>
The resist composition of the present invention includes the acid generator described above and a resin (hereinafter sometimes referred to as “resin (A)”).
The resist composition preferably further contains a basic compound (hereinafter sometimes referred to as “basic compound (C)”) and a solvent (hereinafter sometimes referred to as “solvent (E)”). .
In the resist composition of the present invention, the content of the salt (I) is preferably 1 part by mass or more (more preferably 3 parts by mass or more), preferably 40 parts, relative to 100 parts by mass of the resin (A) described later. It is not more than part by mass (more preferably not more than 35 parts by mass).
When the salt (I) and the acid generator (B) are contained, the total content of the salt (I) and the acid generator (B) is 100 parts by mass of the resin (A). The amount is preferably 1 part by mass or more (more preferably 3 parts by mass or more), preferably 40 parts by mass or less (more preferably 35 parts by mass or less).

<Resin (A)>
Resin (A) contained in the resist composition of the present invention is a resin having an acid labile group and insoluble or hardly soluble in an alkaline aqueous solution, and soluble in an alkaline aqueous solution by the action of an acid. It is. “Can be dissolved in an alkaline aqueous solution by the action of an acid” means “insoluble or hardly soluble in an alkaline aqueous solution before contact with an acid, but soluble in an alkaline aqueous solution after contact with an acid”. means.
The resin (A) can be produced by polymerizing a monomer having an acid labile group (hereinafter, sometimes referred to as “monomer having an acid labile group (a1)”). It becomes alkali-soluble. As the monomer (a1) having an acid labile group, one type may be used alone, or two or more types may be used in combination.

In the present specification, "(meth) acrylic monomer", "CH ₂ = CH-CO-" or _{"CH 2 = C (CH 3)} -CO- " at least one monomer having the structure Means. Similarly, “(meth) acrylate” and “(meth) acrylic acid” mean “at least one of acrylate and methacrylate” and “at least one of acrylic acid and methacrylic acid”, respectively.

<Monomer (a1) having an acid labile group>
The term “acid-labile group” means a group that cleaves a leaving group upon contact with an acid to form a hydrophilic group (for example, a hydroxy group or a carboxy group). Examples of the acid labile group include a group represented by the formula (1) and a group represented by the formula (2).

［式（１）中、Ｒ^a1〜Ｒ^a3は、それぞれ独立に、炭素数１〜８のアルキル基又は炭素数３〜２０の脂環式炭化水素基を表すか、Ｒ^a1及びＲ^a2は互いに結合して炭素数２〜２０の２価の炭化水素基を形成する。＊は結合手を表す。］

［式（２）中、Ｒ^a1'及びＲ^a2'は、それぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表し、Ｒ^a3'は、炭素数１〜２０の炭化水素基を表すか、Ｒ^a2'及びＲ^a3'は互いに結合して炭素数２〜２０の２価の炭化水素基を形成し、該炭化水素基及び２価の基に含まれる−ＣＨ_２−は、−Ｏ―又は―Ｓ−で置き換わってもよい。］

In Expression (1), R ^a1 ~R ^a3 each independently represent a cycloaliphatic hydrocarbon radical of the alkyl group or 3 to 20 carbon atoms having 1 to 8 carbon atoms, R ^a1 and R ^a2 are each Bonding to form a divalent hydrocarbon group having 2 to 20 carbon atoms. * Represents a bond. ]

[In Formula (2), R ^{a1 ′} and R ^{a2 ′} each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^{a3 ′} represents a hydrocarbon group having 1 to 20 carbon atoms. R ^{a2 ′} and R ^{a3 ′} are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms, and —CH ₂ — contained in the hydrocarbon group and the divalent group is — O- or -S- may be substituted. ]

^Examples of the alkyl group represented by R ^{a1 to} R ^a3 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group.
The alicyclic hydrocarbon group may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, and dimethylcyclohexane. Examples thereof include a cycloalkyl group such as a hexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic saturated hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, methylnorbornyl group, and the following groups. In the formula (1), the alicyclic hydrocarbon group preferably has 3 to 16 carbon atoms.

When R ^a1 and R ^a2 are bonded to each other to form a divalent hydrocarbon group, examples of the —C (R ^a1 ) (R ^a2 ) (R ^a3 ) group include groups represented by the following formulae. . Such a divalent hydrocarbon group preferably has 3 to 12 carbon atoms.

Examples of the acid labile group represented by the formula (1) include a 1,1-dialkylalkoxycarbonyl group (in the formula (1), R ^{a1 to} R ^a3 are alkyl groups, preferably tert- Butoxycarbonyl group), 2-alkyladamantan-2-yloxycarbonyl group (in the formula (1), R ^a1 , R ^a2 and a carbon atom form an adamantyl group, and R ^a3 is an alkyl group) and 1- (Adamantan-1-yl) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups, and R ^a3 is an adamantyl group).

Examples of the hydrocarbon group for R ^{a1 ′ to} R ^{a3 ′} include an alkyl group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group.
Examples of the alkyl group and alicyclic hydrocarbon group are the same as those described above.
Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl Groups, phenanthryl groups, 2,6-diethylphenyl groups, aryl groups such as 2-methyl-6-ethylphenyl, and the like.

Preferably, at least one of R ^{a1 ′} and R ^{a2 ′} is a hydrogen atom.
Examples of the group represented by the formula (2) include the following groups.

  The monomer (a1) having an acid labile group is preferably a monomer having an acid labile group and a carbon-carbon double bond, more preferably a (meth) acryl having an acid labile group. Monomer.

  The monomer (a1) is preferably a monomer having both an acid labile group (1) and / or an acid labile group (2) and a carbon-carbon double bond in the molecule, and the acid labile group (1 ) And / or a monomer having both an acid labile group (2) and a (meth) acrylic group in the molecule, and more preferably a (meth) acrylic monomer having an acid labile group (1).

  Of the (meth) acrylic monomers having an acid labile group, those having an alicyclic hydrocarbon group having 5 to 20 carbon atoms are preferred. If a resin obtained by polymerizing the monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group is used, the resolution of the resist can be improved.

  The (meth) acrylic monomer having an acid labile group and an alicyclic hydrocarbon group is preferably a structural unit represented by the formula (a1-1) (hereinafter referred to as “structural unit (a1-1)”). Or a structural unit represented by formula (a1-2) or formula (a1-2) (hereinafter referred to as “structure”). And a monomer for deriving the unit (sometimes referred to as “a1-2)” (hereinafter, sometimes referred to as “monomer (a1-2)”). These may be used alone or in combination of two or more.

［式（ａ１−１）及び式（ａ１−２）中、
Ｌ^a1及びＬ^a2は、それぞれ独立に、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−を表し、ｋ１は１〜７の整数を表し、＊は−ＣＯ−との結合手を表す。
Ｒ^a4及びＲ^a5は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^a6及びＲ^a7は、それぞれ独立に、炭素数１〜８のアルキル基又は炭素数３〜１０の脂環式炭化水素基を表す。
ｍ１は０〜１４の整数を表す。
ｎ１は０〜１０の整数を表す。
ｎ１’は０〜３の整数を表す。］

[In Formula (a1-1) and Formula (a1-2),
L ^a1 and L ^a2 each independently represent —O— or ^* —O— (CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, and * represents a bond to —CO—. Represents a hand.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 10 carbon atoms.
m1 represents the integer of 0-14.
n1 represents an integer of 0 to 10.
n1 ′ represents an integer of 0 to 3. ]

脂環式炭化水素基は、好ましくは炭素数８以下、より好ましくは６以下である。
ｍ１は、好ましくは０〜３の整数、より好ましくは０又は１である。
ｎ１は、好ましくは０〜３の整数、より好ましくは０又は１である。
ｎ１’は好ましくは０又は１である。 L ^a1 and L ^a2 are preferably —O— or ^* —O— (CH ₂ ) _k1 —CO—O—, more preferably —O—. k1 is preferably an integer of 1 to 4, more preferably 1.
R ^a4 and R ^a5 are preferably methyl groups.
^Examples of the alkyl group for R ^a6 and R ^a7 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. The alkyl group for R ^a6 and R ^a7 preferably has 6 or less carbon atoms.
The alicyclic hydrocarbon group for R ^a6 and R ^a7 may be monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, Examples thereof include cycloalkyl groups such as methylcyclohexyl group, dimethylcyclohexyl group, cycloheptyl group, and cyclooctyl group. Examples of the polycyclic saturated hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, methylnorbornyl group, and the following groups.

The alicyclic hydrocarbon group preferably has 8 or less carbon atoms, more preferably 6 or less.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 ′ is preferably 0 or 1.

Examples of the monomer represented by the formula (a1-1) include monomers described in JP 2010-204646 A. Monomers represented by the following formulas (a1-1-1) to (a1-1-8) are preferred, and monomers represented by the following formulas (a1-1-1) to (a1-1-4) are more preferred. .

Examples of the monomer represented by the formula (a1-2) include 1-ethylcyclopentan-1-yl (meth) acrylate, 1-ethylcyclohexane-1-yl (meth) acrylate, 1-ethylcycloheptane-1 -Yl (meth) acrylate, 1-methylcyclopentan-1-yl (meth) acrylate, 1-isopropylcyclopentan-1-yl (meth) acrylate and the like. Monomers represented by the following formulas (a1-2-1) to (a1-2-6) are preferred, and monomers represented by the following formulas (a1-2-3) to (a1-2-4) are more preferred. A monomer represented by the following formula (a1-2-3) is more preferable.

  The content of the structural unit (a1-1) and / or the structural unit (a1-2) in the resin (A) is usually 10 to 95 mol% in all structural units of the resin (A), preferably 15 to It is 90 mol%, More preferably, it is 20-85 mol%.

式（ａ１−５）中、
Ｒ^３１は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｌ^３〜Ｌ^５は、オキシ基、チオキシ基又は^＊−Ｏ−（ＣＨ₂）_k4−ＣＯ−Ｏ−で表される基を表す。ここで、ｋ４は１〜７の整数を表し、＊はカルボニル基（−ＣＯ−）との結合手である。
Ｚ^１’は、単結合又は炭素数１〜６のアルカンジイル基であり、該アルカンジイル基中に含まれるメチレン基は、オキシ基又はカルボニル基に置き換わっていてもよい。
ｓ１及びｓ１’は、それぞれ独立して、０〜４の整数を表す。 As the other monomer (a1), for example, a monomer represented by the formula (a1-5) which is a (meth) acrylic monomer having an acid labile group (2) (hereinafter referred to as “monomer (a1-5)”) May be used).

In formula (a1-5),
R ³¹ represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
L ^{3 to} L ⁵ represent an oxy group, a thioxy group, or a group represented by ^* —O— (CH ₂ ) _k4 —CO—O—. Here, k4 represents an integer of 1 to 7, and * is a bond with a carbonyl group (—CO—).
Z ^{1 ′} is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the methylene group contained in the alkanediyl group may be replaced with an oxy group or a carbonyl group.
s1 and s1 ′ each independently represents an integer of 0 to 4.

In formula (a1-5), R ³¹ is preferably a hydrogen atom, a methyl group, or a trifluoromethyl group.
L ⁵ is preferably an oxygen atom.
One of L ³ and L ⁴ is preferably an oxygen atom and the other is a sulfur atom.
s1 is preferably 1.
s1 ′ is preferably an integer of 0 to 2.
Z ^{1 ′} is preferably a single bond or —CH ₂ —CO—O—.

Examples of the monomer (a1-5) include the following monomers.

  When the resin (A) has a structural unit derived from the monomer (a1-5), the content thereof is in the range of 1 to 95 mol% with respect to all the structural units (100 mol%) of the resin (A). Is preferable, the range of 3-90 mol% is more preferable, and the range of 5-85 mol% is further more preferable.

<Acid stable monomer>
The resin (A) is preferably a co-polymerization of a monomer (a1) having an acid labile group and a monomer having no acid labile group (hereinafter sometimes referred to as “acid stable monomer”). It is a coalescence. An acid stable monomer may be used individually by 1 type, and may use 2 or more types together.
When the resin (A) is a copolymer of a monomer (a1) having an acid labile group and an acid stable monomer, the structural units derived from the monomer (a1) having an acid labile group are all Preferably it is 10-80 mol% with respect to 100 mol% of structural units, More preferably, it is 20-60 mol%. Further, the content of the structural unit derived from the monomer having an adamantyl group (particularly the monomer (a1-1) having an acid labile group) is preferably relative to the monomer (a1) having an acid labile group. 15 mol% or more. When the ratio of the monomer having an adamantyl group is increased, the dry etching resistance of the resist is improved.

  As an acid stable monomer, Preferably, the monomer which has a hydroxyl group or a lactone ring is mentioned. Acid-stable monomer having a hydroxy group (hereinafter sometimes referred to as “acid-stable monomer having a hydroxy group (a2)”) or acid-stable monomer having a lactone ring (hereinafter referred to as “acid-stable monomer having a lactone ring (a3)”) If a resin having a structural unit derived from (sometimes) is used, the resolution of the resist and the adhesion to the substrate can be improved.

<Acid-stable monomer having a hydroxy group (a2)>
When the resist composition is used for KrF excimer laser exposure (248 nm), high energy beam exposure such as electron beam or EUV light, the acid-stable monomer (a2) having a hydroxy group is preferably a phenolic hydroxy which is a hydroxystyrene. The acid-stable monomer (a2-0) having a group is used.
On the other hand, when using short-wavelength ArF excimer laser exposure (193 nm) or the like, the acid-stable monomer (a2) having a hydroxy group is preferably acid-stable having a hydroxyadamantyl group represented by the formula (a2-1) Use monomers. The acid-stable monomer (a2) having a hydroxy group may be used alone or in combination of two or more.

［式（ａ２−０）中、
Ｒ^a30は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｒ^a31は、ハロゲン原子、ヒドロキシ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜４のアシル基、炭素数２〜４のアシルオキシ基、アクリロイル基又はメタクリロイル基を表す。
ｍａは０〜４の整数を表す。ｍａが２以上の整数である場合、複数のＲ^a31は同一であっても異なってもよい。］ Examples of the monomer (a2-0) having a phenolic hydroxy group include styrene monomers such as p- or m-hydroxystyrene represented by the formula (a2-0).

[In the formula (a2-0),
R ^a30 represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
R ^a31 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyl group, or methacryloyl. Represents a group.
ma represents an integer of 0 to 4. When ma is an integer of 2 or more, the plurality of R ^a31 may be the same or different. ]

^Examples of the alkyl group for R ^a30 and R ^a31 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, and n-hexyl group. Preferably, it is a C1-C4 alkyl group, More preferably, it is a C1-C2 alkyl group, Most preferably, it is a methyl group.
Examples of the alkoxy group for R ^a31 include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentoxy group, and an n-hexoxy group. Preferably an alkoxy group having 1 to 4 carbon atoms, more preferably an alkoxy group having 1 or 2 carbon atoms, and particularly preferably a methoxy group.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, and an isobutyryloxy group.
ma is preferably 0 to 2, more preferably 0 or 1, and particularly preferably 0.

In order to obtain a copolymer resin having a structural unit derived from a monomer having such a phenolic hydroxy group, the corresponding (meth) acrylic acid ester monomer and acetoxystyrene and / or other polymerizable monomer were radically polymerized. Thereafter, it can be obtained by deacetylation using a base.
As a monomer which has a phenolic hydroxy group, the monomer described in Unexamined-Japanese-Patent No. 2010-204634 is mentioned, for example. Monomers represented by the following formulas (a2-0-1) and (a2-0-2) are preferred. When manufacturing resin (A), what protected the phenolic hydroxy group in these with the suitable protective group can also be used.

  When the resin (A) has a structural unit derived from the acid-stable monomer (a2-0), the content is usually from 5 to 90 mol%, preferably from 10 to 85 mol% in all units of the resin. More preferably, it is 15-80 mol%.

式（ａ２−１）中、
Ｌ^a3は、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k2−ＣＯ−Ｏ−を表し、
ｋ２は１〜７の整数を表す。＊は−ＣＯ−との結合手を表す。
Ｒ^a14は、水素原子又はメチル基を表す。
Ｒ^a15及びＲ^a16は、それぞれ独立に、水素原子、メチル基又はヒドロキシ基を表す。
ｏ１は、０〜１０の整数を表す。 Examples of the acid stable monomer having a hydroxyadamantyl group include a monomer represented by the formula (a2-1).

In formula (a2-1),
L ^a3 represents —O— or ^* —O— (CH ₂ ) _k2 —CO—O—,
k2 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 each independently represent a hydrogen atom, a methyl group or a hydroxy group.
o1 represents an integer of 0 to 10.

In the formula (a2-1), L ^a3 is preferably, -O -, - O- (CH 2) f1 -CO-O- and is (wherein f1 is an integer from 1 to 4), more preferably Is —O—.
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, more preferably 0 or 1.

As an acid stable monomer (a2-1) which has a hydroxyadamantyl group, the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Monomers represented by the following formulas (a2-1-1) to (a2-1-6) are preferable, respectively, and monomers represented by the following formulas (a2-1-1) to (a2-1-4) are respectively used. More preferred are monomers represented by the following formulas (a2-1-1) or (a2-1-3), respectively.

  When the resin (A) has a structural unit derived from the monomer represented by the formula (a2-1), the content is usually 3 to 45 mol% in all units of the resin (A), preferably Is from 5 to 40 mol%, more preferably from 5 to 35 mol%, still more preferably from 5 to 20 mol%.

<Acid-stable monomer having a lactone ring (a3)>
The lactone ring possessed by the acid stable monomer (a3) may be, for example, a monocycle such as a β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, and a monocyclic lactone ring and other rings The condensed ring may be used. Among these lactone rings, a γ-butyrolactone ring or a condensed ring of γ-butyrolactone ring and another ring is preferable.

  The acid-stable monomer (a3) having a lactone ring is preferably represented by the formula (a3-1), the formula (a3-2) or the formula (a3-3). These 1 type may be used independently and may use 2 or more types together.

式（ａ３−１）〜式（ａ３−３）中、
Ｌ^a4〜Ｌ^a6は、それぞれ独立に、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−を表す。
ｋ３は１〜７の整数を表す。＊は−ＣＯ−との結合手を表す。
Ｒ^a18〜Ｒ^a20は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^a21は、炭素数１〜４のアルキル基を表す。
ｐ１は０〜５の整数を表す。
Ｒ^a22及びＲ^a23は、それぞれ独立に、カルボキシ基、シアノ基又は炭素数１〜４のアルキル基を表す。
ｑ１及びｒ１は、それぞれ独立に０〜３の整数を表す。
ｐ１が２以上のとき、複数のＲ^a21の全部又は一部は同じであってもよい。
ｑ１が２以上のとき、複数のＲ^a22の全部又は一部は同じであってもよい。
ｒ１が２以上のとき、複数のＲ^a23の全部又は一部は同じであってもよい。

In formula (a3-1) to formula (a3-3),
L ^{a4 to} L ^a6 each independently represent —O— or ^* —O— (CH ₂ ) _k3 —CO—O—.
k3 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^{a18 to} R ^a20 each independently represents a hydrogen atom or a methyl group.
R ^a21 represents an alkyl group having 1 to 4 carbon atoms.
p1 represents an integer of 0 to 5.
R ^a22 and R ^a23 each independently represent a carboxy group, a cyano group, or an alkyl group having 1 to 4 carbon atoms.
q1 and r1 each independently represents an integer of 0 to 3.
When p1 is 2 or more, all or some of the plurality of R ^a21 may be the same.
When q1 is 2 or more, all or some of the plurality of R ^a22 may be the same.
When r1 is 2 or more, all or some of the plurality of R ^a23 may be the same.

In the formula (a3-1) to the formula (a3-3), examples of L ^{a4 to} L ^a6 include those described for L ^a3 .
L ^{a4 to} L ^a6 are each independently preferably —O— or ^* —O— (CH ₂ ) _k3 —CO—O—, more preferably —O—. k3 is preferably an integer of 1 to 4, more preferably 1.
R ^{a18 to} R ^a21 are each independently preferably a methyl group.
R ^a22 and R ^a23 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1 to r1 are each independently preferably 0 to 2, more preferably 0 or 1.

Examples of the acid-stable monomer (a3) having a lactone ring include monomers described in JP 2010-204646 A. The following formulas (a3-1-1) to (a3-1-4), (a3-2-1) to (a3-2-4), (a3-3-1) to (a3-3-4), respectively Are preferable, and monomers represented by the following formulas (a3-1-1) to (a3-1-2) and (a3-2-3) to (a3-2-4) are more preferable, respectively. More preferably, monomers represented by the following formula (a3-1-1) or (a3-2-3), respectively.

When the resin (A) has a structural unit derived from the acid-stable monomer (a3) having a lactone ring, the total content is usually from 5 to 70 mol%, preferably from 10 to 10% in all structural units of the resin. It is 65 mol%, More preferably, it is 10-60 mol%.
The content of each of the structural unit derived from the monomer (a3-1), the structural unit derived from the monomer (a3-2), and the structural unit derived from the monomer (a3-3) is the total structure of the resin (A). 5-60 mol% is preferable with respect to a unit (100 mol%), the range of 5-50 mol% is more preferable, and the range of 10-50 mol% is more preferable.

<Other monomer (a4)>
The resin may have a structural unit derived from another known monomer (a4) other than the above-mentioned monomers. Hereinafter, such an acid stable monomer may be referred to as “other monomer (a4)”.

  Preferably, the resin (A) polymerizes at least the monomer (a1) having an acid labile group, the acid stable monomer (a2) having a hydroxy group, and / or the acid stable monomer (a3) having a lactone ring. Copolymer. In the copolymer, the monomer (a1) having an acid labile group is more preferably at least one of a monomer (a1-1) having an adamantyl group and a monomer (a1-2) having a cyclohexyl group. (More preferably, the monomer (a1-1) having an adamantyl group), and the acid-stable monomer (a2) having a hydroxy group is preferably an acid-stable monomer (a2-1) having a hydroxyadamantyl group, and a lactone ring More preferably, the acid-stable monomer (a3) having a γ-butyrolactone ring and an acid-stable monomer (a3-1) having a condensed ring of a γ-butyrolactone ring and a norbornane ring are used. At least one. Resin (A) can be manufactured by a well-known polymerization method (for example, radical polymerization method).

The weight average molecular weight of the resin (A) is preferably 2,500 or more, more preferably 3,000 or more, and further preferably 4,000 or more. The upper limit of the weight average molecular weight is preferably 50,000 or less, more preferably 30,000 or less, and even more preferably 15,000 or less.
The content of the resin (A) is preferably 80% by mass or more and 99% by mass or less in the solid content of the composition. The “solid content in the composition” means the total of resist composition components excluding the solvent (E) described later. The solid content in the composition and the content of the resin (A) relative thereto can be measured, for example, by a known analysis means such as liquid chromatography or gas chromatography.

<Basic compound (hereinafter sometimes referred to as “basic compound (C)”)>
The basic compound (C) acts as a quencher.
The basic compound (C) is preferably a basic nitrogen-containing organic compound, and examples thereof include amines and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines. The basic compound (C) is preferably a compound represented by the formula (C1) to a compound represented by the formula (C8), more preferably a compound represented by the formula (C1-1). It is done.

［式（Ｃ１）中、Ｒ^c1、Ｒ^c2及びＲ^c3は、それぞれ独立に、水素原子、炭素数１〜６のアルキル基、炭素数５〜１０の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基を表し、該アルキル基及び該脂環式炭化水素基に含まれる水素原子は、ヒドロキシ基、アミノ基又は炭素数１〜６のアルコキシ基で置換されていてもよく、該芳香族炭化水素基に含まれる水素原子は、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数５〜１０の脂環式炭化水素又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよい。］

[In formula (C1), R ^c1 , R ^c2 and R ^c3 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 5 to 10 carbon atoms, or 6 to 6 carbon atoms. 10 represents an aromatic hydrocarbon group, and the hydrogen atom contained in the alkyl group and the alicyclic hydrocarbon group may be substituted with a hydroxy group, an amino group or an alkoxy group having 1 to 6 carbon atoms, The hydrogen atom contained in the aromatic hydrocarbon group is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon having 5 to 10 carbon atoms, or an aromatic group having 6 to 10 carbon atoms. It may be substituted with a group hydrocarbon group. ]

［式（Ｃ１−１）中、Ｒ^c2及びＲ^c3は、上記と同じ意味を表す。
Ｒ^c4は、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数５〜１０の脂環式炭化水素又は炭素数６〜１０の芳香族炭化水素基を表す。
ｍ３は０〜３の整数を表し、ｍ３が２以上のとき、複数のＲ^c4の全部又は一部は同じであってもよい。］

[In Formula (C1-1), R ^c2 and R ^c3 represent the same meaning as described above.
R ^c4 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon having 5 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.
m3 represents an integer of 0 to 3, and when m3 is 2 or more, all or some of the plurality of R ^c4 may be the same. ]

［式（Ｃ２）、式（Ｃ３）及び式（Ｃ４）中、Ｒ^c5、Ｒ^c6、Ｒ^c7及びＲ^c8は、それぞれ独立に、Ｒ^c1と同じ意味を表す。
Ｒ^c9は、炭素数１〜６のアルキル基、炭素数３〜６の脂環式炭化水素基又は炭素数２〜６のアルカノイル基を表す。
ｎ３は０〜８の整数を表し、ｎ３が２以上のとき、複数のＲ^c9の全部又は一部は同じであってもよい。］

[In Formula (C2), Formula (C3) and Formula (C4), R ^c5 , R ^c6 , R ^c7 and R ^c8 each independently represent the same meaning as R ^c1 .
R ^c9 represents an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 3 to 6 carbon atoms, or an alkanoyl group having 2 to 6 carbon atoms.
n3 represents an integer of 0 to 8, and when n3 is 2 or more, all or some of the plurality of R ^c9 may be the same. ]

［式（Ｃ５）及び式（Ｃ６）中、Ｒ^c10、Ｒ^c11、Ｒ^c12、Ｒ^c13及びＲ^c16は、それぞれ独立に、Ｒ^c1と同じ意味を表す。
Ｒ^c14、Ｒ^c15及びＲ^c17は、それぞれ独立に、Ｒ^c4と同じ意味を表す。
ｏ３及びｐ３は、それぞれ独立に０〜３の整数を表し、ｏ３又はｐ３が２以上であるとき、それぞれ、複数のＲ^c14及びＲ^c15の全部又は一部は同じであってもよい。
Ｌ^c1は、炭素数１〜６のアルカンジイル基、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｓ−又はこれらを組合せた２価の基を表す。］

[In Formula (C5) and Formula (C6), R ^c10 , R ^c11 , R ^c12 , R ^c13 and R ^c16 each independently represent the same meaning as R ^c1 .
R ^c14 , R ^c15 and R ^c17 each independently represent the same meaning as R ^c4 .
o3 and p3 each independently represent an integer of 0 to 3. When o3 or p3 is 2 or more, all or a part of the plurality of R ^c14 and R ^c15 may be the same.
L ^c1 represents an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

［式（Ｃ７）及び式（Ｃ８）中、Ｒ^c18、Ｒ^c19及びＲ^c20は、それぞれ独立に、Ｒ^c4と同じ意味を表す。
ｑ３、ｒ３及びｓ３は、それぞれ独立に０〜３の整数を表し、ｑ３、ｒ３及びｓ３が２以上であるとき、それぞれ、複数のＲ^c18、Ｒ^c19及びＲ^c20の全部又は一部は同じであってもよい。
Ｌ^c2は、単結合又は炭素数１〜６のアルカンジイル基、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｓ−又はこれらを組合せた２価の基を表す。］

Wherein (C7) and formula ^{(C8), R c18, R} c19 and R ^c20 in each occurrence independently represent the same meaning as R ^c4.
q3, r3 and s3 each independently represent an integer of 0 to 3, when q3, r3 and s3 is 2 or more, respectively, all or a portion of the plurality of R ^c18, R ^c19 and R ^{c 20} at the same There may be.
L ^c2 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

In the formulas (C1) to (C8), examples of the alkyl group, the alicyclic hydrocarbon group, the aromatic hydrocarbon group, the alkoxy group, and the alkanediyl group are the same as those described above.
Examples of the alkanoyl group include acetyl group, 2-methylacetyl group, 2,2-dimethylacetyl group, propionyl group, butyryl group, isobutyryl group, pentanoyl group, and 2,2-dimethylpropionyl group.

  Examples of the compound represented by the formula (C1) include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N- Dimethylaniline, diphenylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tri Pentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyl Hexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonyl Amine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2- Examples include diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, and preferably diisopropyl. Piruanirin. Particularly preferred include 2,6-diisopropylaniline.

Examples of the compound represented by the formula (C2) include piperazine.
Examples of the compound represented by the formula (C3) include morpholine.
Examples of the compound represented by the formula (C4) include piperidine and hindered amine compounds having a piperidine skeleton described in JP-A No. 11-52575.
Examples of the compound represented by the formula (C5) include 2,2′-methylenebisaniline.
Examples of the compound represented by the formula (C6) include imidazole and 4-methylimidazole.
Examples of the compound represented by the formula (C7) include pyridine and 4-methylpyridine.
Examples of the compound represented by the formula (C8) include 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,2-di (2-pyridyl) ethene, 1, 2-di (4-pyridyl) ethene, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyloxy) ethane, di (2-pyridyl) ketone, 4,4′-dipyridyl sulfide 4,4′-dipyridyl disulfide, 2,2′-dipyridylamine, 2,2′-dipiconylamine, bipyridine and the like.

  As ammonium salts, tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3- (trifluoromethyl) phenyltrimethyl Ammonium hydroxide, tetra-n-butylammonium salicylate, choline and the like can be mentioned.

  The content of the basic compound (C) is preferably about 0.01 to 5% by mass, more preferably about 0.01 to 3% by mass, and particularly preferably based on the solid content of the resist composition. It is about 0.01-1 mass%.

<Solvent (sometimes referred to as "solvent (E)")
The solvent (E) contained in the resist composition of the present invention is, for example, 90% by mass or more, preferably 92% by mass or more, more preferably 94% by mass or more in the resist composition. It is contained at 99.9% by mass or less, preferably 99% by mass or less.
The content rate of a solvent (E) can be measured by well-known analysis means, such as a liquid chromatography or a gas chromatography, for example.

  Examples of the solvent (E) include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate; glycol ethers such as propylene glycol monomethyl ether; ethyl lactate, butyl acetate, amyl acetate and And esters such as ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; A solvent (E) may be used individually by 1 type, and may use 2 or more types together.

<Other components (hereinafter sometimes referred to as “other components (F)”)>
The resist composition of this invention may contain the other component (F) as needed. There is no particular limitation on the component (F), and additives known in the resist field, for example, polymer compounds other than the resin (A) (for example, the above-mentioned acid-stable monomer and / or copolymer of known monomers), Examples include sensitizers, dissolution inhibitors, surfactants, stabilizers, and dyes.

<Method for preparing resist composition>
The resist composition can be usually prepared by mixing the salt (I) and the resin (A) in the presence of the solvent (D). Furthermore, you may mix an acid generator (B), a basic compound (C), and / or a component (F) as needed as above-mentioned. The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select an appropriate temperature range from the range of 10-40 degreeC according to the kind etc. of resin, the solubility with respect to solvent (E), such as resin. An appropriate mixing time can be selected from 0.5 to 24 hours depending on the mixing temperature. The mixing means is not particularly limited, and stirring and mixing can be used.
By selecting the amount of each component used when preparing the resist composition of the present invention, the content of each component in the resist composition of the present invention can be adjusted.

  Thus, after mixing resin (A) and acid generator (B) and each of basic compound (C), solvent (E) or component (F) used as necessary, at a preferred content, A resist composition can be prepared by filtering using a filter having a pore size of about 0.003 to 0.2 μm.

<Method for producing resist pattern>
The method for producing a resist pattern of the present invention comprises:
(1) The process of apply | coating the resist composition of this invention on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) A step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.

  Application of the resist composition onto the substrate can be performed by a commonly used apparatus such as a spin coater.

The composition after application is dried to remove the solvent. For drying, for example, the coating film is dried by heating means using a heating device such as a hot plate (so-called pre-baking), decompressing means using a decompression device, or a combination of these means, and the solvent (D) Remove. The temperature in this case is preferably about 50 to 200 ° C., for example. The pressure is preferably about 1 to 1.0 × 10 ⁵ Pa.

The obtained composition layer is usually exposed using an exposure machine. The exposure machine may be an immersion exposure machine. At this time, exposure is usually performed through a mask (photomask) on which a required pattern is formed. Exposure light sources include those that emit laser light in the ultraviolet region such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), solid-state laser light source (YAG or semiconductor laser) Etc.) can be used such as those that convert the wavelength of the laser light from the above and radiate the harmonic laser light in the far ultraviolet region or the vacuum ultraviolet region. The exposure machine may irradiate an electron beam or extreme ultraviolet light (EUV). In this specification, irradiating these radiations may be collectively referred to as “exposure”.

The composition layer after the exposure is subjected to heat treatment for promoting the deprotection group reaction. As heating temperature, it is about 50-200 degreeC normally, Preferably it is about 70-150 degreeC.
The heated composition layer is usually developed using an alkali developer using a developing device.
The alkaline developer may be various alkaline aqueous solutions used in this field. Examples thereof include an aqueous solution of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline).
After development, it is preferable to rinse with ultrapure water to remove water remaining on the substrate and the pattern.

<Application>
The resist composition of the present invention includes a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) irradiation, or a resist composition or liquid for an EUV exposure machine. It is suitable as a resist composition for immersion exposure and useful for fine processing of semiconductors.

The present invention will be described more specifically with reference to examples. In the examples, “%” and “parts” representing the content or amount used are based on mass unless otherwise specified. The weight average molecular weight is a value determined by gel permeation chromatography. The analysis conditions for gel permeation chromatography are as follows.
Apparatus: HLC-8120GPC type (manufactured by Tosoh Corporation)
Column: TSKgel Multipore H _XL -M x 3 + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

  The structure of the compound was confirmed by measuring molecular peaks using mass spectrometry (LC: Agilent model 1100, MASS: Agilent LC / MSD model). In the following examples, the value of this molecular peak is indicated by “MASS”.

式（Ｉ１−ａ）で表される化合物２．００部及びアセトニトリル１０部を添加し、２３℃で２時間攪拌した。得られた混合溶液を０℃まで冷却し、水素化ホウ素ナトリウム０．３３部及びイオン交換水４．８８部の混合液を１０分かけて滴下し、さらに、０℃で３時間攪拌した。得られた反応マスに、１Ｎ塩酸８．６１部を添加し、濃縮し、クロロホルム４０部及びイオン交換水１００部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この操作を４回繰り返した。回収された有機層をろ過し、ろ液を濃縮することにより、式（Ｉ１−ｂ）で表される塩１．３７部を得た。 Example 1: Synthesis of a salt represented by the formula (I1)

2.00 parts of a compound represented by the formula (I1-a) and 10 parts of acetonitrile were added and stirred at 23 ° C. for 2 hours. The obtained mixed solution was cooled to 0 ° C., a mixed solution of 0.33 part of sodium borohydride and 4.88 parts of ion-exchanged water was added dropwise over 10 minutes, and further stirred at 0 ° C. for 3 hours. To the obtained reaction mass, 8.61 parts of 1N hydrochloric acid was added, concentrated, 40 parts of chloroform and 100 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to take out the organic layer. This operation was repeated 4 times. The collected organic layer was filtered and the filtrate was concentrated to obtain 1.37 parts of the salt represented by the formula (I1-b).

式（Ｉ１−ｃ）で表される塩２．９６部、（Ｉ１−ｂ）で表される化合物０．４８部及びモノクロロベンゼン２４．００部を仕込み、２３℃で３０分間攪拌した。得られた混合液に、二安息香酸銅（ＩＩ）０．０３部を添加し、さらに、１００℃で３０分間攪拌した。得られた反応溶液を濃縮した。得られた残渣に、クロロホルム４５部及びイオン交換水１１．２５部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この操作を４回繰り返した。得られた有機層を濃縮し、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル２０．９０部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮した。得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル２４．２０部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ１）で表される塩１．６７部を得た。

2.96 parts of a salt represented by the formula (I1-c), 0.48 parts of a compound represented by (I1-b) and 24.00 parts of monochlorobenzene were charged and stirred at 23 ° C. for 30 minutes. To the resulting mixture, 0.03 part of copper (II) dibenzoate was added, and the mixture was further stirred at 100 ° C. for 30 minutes. The resulting reaction solution was concentrated. To the obtained residue, 45 parts of chloroform and 11.25 parts of ion-exchanged water were added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This operation was repeated 4 times. The obtained organic layer was concentrated, and 20.90 parts of tert-butyl methyl ether was added to the obtained residue and stirred, and the supernatant was removed. The resulting residue was dissolved in acetonitrile and concentrated. To the obtained residue, 24.20 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 1.67 parts of the salt represented by the formula (I1).

MASS (ESI (+) Spectrum): M ⁺ 251.2
MASS (ESI (−) Spectrum): M ^- 339.1

式（Ｉ３−ｃ）で表される塩２．９０部、（Ｉ１−ｂ）で表される化合物０．４８部及びモノクロロベンゼン２４．００部を仕込み、２３℃で３０分間攪拌した。得られた混合液に、二安息香酸銅（ＩＩ）０．０３部を添加し、さらに、１００℃で３０分間攪拌した。得られた反応溶液を濃縮した。得られた残渣に、クロロホルム４０部及びイオン交換水１５部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この操作を４回繰り返した。得られた有機層を濃縮し、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル２０部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮した。得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル２０部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ３）で表される塩１．２３部を得た。 Example 2: Synthesis of a salt represented by the formula (I3)

2.90 parts of a salt represented by the formula (I3-c), 0.48 parts of a compound represented by (I1-b) and 24.00 parts of monochlorobenzene were charged and stirred at 23 ° C. for 30 minutes. To the resulting mixture, 0.03 part of copper (II) dibenzoate was added, and the mixture was further stirred at 100 ° C. for 30 minutes. The resulting reaction solution was concentrated. To the obtained residue, 40 parts of chloroform and 15 parts of ion-exchanged water were added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This operation was repeated 4 times. The obtained organic layer was concentrated, and 20 parts of tert-butyl methyl ether was added to the resulting residue and stirred, and the supernatant was removed. The resulting residue was dissolved in acetonitrile and concentrated. To the obtained residue, 20 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 1.23 parts of the salt represented by the formula (I3).

MASS (ESI (+) Spectrum): M ⁺ 251.2
MASS (ESI (-) Spectrum): M ^- 323.0

Resin synthesis The monomers used are shown below. These monomers are referred to as “monomer (A)” to “monomer (G)”.

[Synthesis of Resin A1]
Monomer (A), monomer (E), monomer (B), monomer (C) and monomer (D) were charged at a molar ratio of 30: 14: 6: 20: 30. Subsequently, 1.5 mass times dioxane was added with respect to the total mass of all the monomers. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators in proportions of 1 mol% and 3 mol%, respectively, with respect to the total number of moles of all monomers. This was heated at 75 ° C. for about 5 hours. Thereafter, the reaction solution is purified by pouring it into a large amount of methanol / water mixed solvent (4: 1) and precipitating three times, and the weight average molecular weight is about 7.2 × 10 ^3. The coalescence was obtained with a yield of 78%. This copolymer has a structural unit of the following formula, and this is designated as resin A1.

[Synthesis of Resin A2]
Monomer (F), monomer (C) and monomer (B) were charged at a molar ratio of 40:40:20, and then 1.5 mass times dioxane was added to the total mass of all monomers. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were 0.8 mol% and 2.4 mol%, respectively, with respect to the total number of moles of all monomers. And heated at 70 ° C. for about 5 hours. Thereafter, the reaction solution is purified by pouring it into a large amount of methanol / water mixed solvent (3: 1) and precipitating three times, and the weight average molecular weight is about 1.0 × 10 ^4. The coalescence was obtained with a yield of 78%. This copolymer has a structural unit of the following formula, and this is designated as resin A2.

[Synthesis of Resin A3]
Monomer (A), monomer (E), monomer (B), monomer (D) and monomer (C) are mixed in a molar ratio of 30: 14: 6: 20: 30. 5 mass times dioxane was added to make a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and these were heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The obtained resin was again dissolved in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 7.2. A × 10 ³ copolymer A3 was obtained with a yield of 78%. This resin A3 has the following structural units.

[Synthesis of Resin A4]
Monomer (A), monomer (G), monomer (B), monomer (D) and monomer (C) are mixed in a molar ratio of 30: 14: 6: 20: 30. 5 mass times dioxane was added to make a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and these were heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The obtained resin was again dissolved in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 7.2. A × 10 ³ copolymer A4 was obtained with a yield of 78%. This resin A4 has the following structural units.

<Preparation of resist composition>
As shown in Table 3, the following components were mixed, and the resulting mixture was filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

Ｉ３：実施例２で合成

Ｂ１：特開２０１０−１５２３４１号公報の実施例に従って合成

Ｂ２：特開２０１０−６１０１８号公報の実施例に従って合成

＜塩基性化合物：クエンチャー＞
Ｃ１：２，６−ジイソプロピルアニリン（東京化成工業（株）製）
＜溶剤＞
プロピレングリコールモノメチルエーテルアセテート ２６５．０部
２−ヘプタノン ２０．０部
プロピレングリコールモノメチルエーテル ２０．０部
γ−ブチロラクトン ３．５部 <Resin>
Resin A1
Resin A2
Resin A3
Resin A4
<Acid generator>
I1: Synthesis in Example 1

I3: synthesized in Example 2

B1: Synthesis according to the example of JP 2010-152341 A

B2: synthesized according to the example of JP 2010-61018 A

<Basic compound: Quencher>
C1: 2,6-diisopropylaniline (manufactured by Tokyo Chemical Industry Co., Ltd.)
<Solvent>
Propylene glycol monomethyl ether acetate 265.0 parts 2-heptanone 20.0 parts Propylene glycol monomethyl ether 20.0 parts γ-butyrolactone 3.5 parts

<Manufacture of resist pattern and its evaluation>
An organic antireflective coating composition (ARC-29; manufactured by Nissan Chemical Co., Ltd.) is applied to a silicon wafer and baked at 205 ° C. for 60 seconds to form an organic antireflective coating having a thickness of 78 nm. Formed. Next, each of the resist compositions shown in Table 3 was spin-coated on the organic antireflection film so that the film thickness after drying (pre-baking) was 85 nm.
The silicon wafer coated with the resist composition was pre-baked on a direct hot plate at a temperature described in the “PB” column of Table 3 for 60 seconds to form a resist film.
ArF excimer stepper for immersion exposure (XT: 1900Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light) on a silicon wafer on which a resist film is formed, and a contact hole pattern (hole pitch 100 nm / Using a mask for forming a hole diameter of 70 nm, exposure was performed while changing the exposure amount stepwise. Note that ultrapure water was used as the immersion medium.
After the exposure, the silicon wafer was post-exposure baked on a hot plate for 60 seconds at the temperature described in the “PEB” column of Table 3. Next, this silicon wafer was subjected to paddle development for 60 seconds with a 2.38% tetramethylammonium hydroxide aqueous solution to obtain a resist pattern.

  In each resist film, an exposure amount at which the hole diameter of a pattern formed with a mask having a hole diameter of 70 nm was 55 nm was defined as effective sensitivity.

<Focus margin evaluation (DOF)>
In the effective sensitivity, when the focus was changed, the range (52.5 to 57.7 nm) in which the line width was 55 nm ± 5% was used as the line width index, and the DOF was evaluated according to the following four levels. In other words, those having a DOF of 0.17 μm or more are indicated with “◎”,
“○” indicates that the thickness is 0.12 μm or more and less than 0.17 μm,
What was less than 0.12 micrometer was made into "x".
The results are shown in Table 4.

  If the resist composition containing the salt of the present invention is used, a resist pattern having an excellent focus margin (DOF) can be produced.

Claims (8)

A salt represented by the formula (I).

[In the formula (I),
R ¹ and R ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. .
Y represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent; —CH ₂ — contained in the aromatic hydrocarbon group and the alicyclic hydrocarbon group may be replaced by —O—, —SO ₂ — or —CO—.
m and n each independently represents 1 or 2.
R ³ and R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
When m is 2, a plurality of R ³ may be the same as or different from each other.
When n is 2, a plurality of R ⁴ may be the same as or different from each other.
R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represents a hydrogen atom, a hydroxy group or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group is , -O- or -CO-. ] The salt according to claim 1, wherein m and n are 2, and R ³ and R ⁴ are both hydrogen atoms. L ¹ is * —CO—O— (CH ₂ ) _n — (* represents a bond to the carbon atom of —C (R ¹ ) (R ² ) —, and n represents 0 or 1). The salt according to claim 1 or 2, wherein   The acid generator containing the salt in any one of Claims 1-3.   A resin comprising an acid generator according to claim 4 and a resin, wherein the resin has an acid labile group and is insoluble or hardly soluble in an alkaline aqueous solution, and can be dissolved in an alkaline aqueous solution by the action of an acid. Resist composition which is resin.   The resist composition according to claim 5, further comprising a solvent.   Furthermore, the resist composition of Claim 5 or 6 containing a basic compound. (1) The process of apply | coating the resist composition in any one of Claims 5-7 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including: