JP6932943B2 - Method for Producing Salt, Resist Composition and Resist Pattern - Google Patents

Description

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

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

Patent Document 2 describes a resist composition containing a salt represented by the following formula as a salt for an acid generator.

Japanese Unexamined Patent Publication No. 2012-224611 Japanese Unexamined Patent Publication No. 2004-059882

In the resist composition containing the salt represented by the above formula, the CD uniformity (CDU) of the resist pattern may not always be sufficiently satisfied.

［式（Ｉ）中、
Ｒ^１及びＲ^２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。
ｍ及びｎは、それぞれ独立に、１又は２を表す。ｍが２のとき、２つのＲ^１は同一又は相異なり、ｎが２のとき、２つのＲ^２は同一又は相異なる。
Ｘは、酸素原子又は硫黄原子を表す。
Ａｒは、電子吸引基を有する炭素数６〜３６の芳香族炭化水素基又は電子吸引基を有する炭素数６〜３６のヘテロ芳香族炭化水素基を表す。
Ａ⁻は、ハロゲン化物イオン、ヒドロキシドイオン又は有機アニオンを表す。］
［２］有機アニオンが、有機スルホン酸アニオンである［１］に記載の塩。
［３］有機アニオンが、式（Ｉ−Ａ）で表されるアニオンである［１］又は［２］に記載の塩。

［式（Ｉ−Ａ）中、Ｌ^b1は、炭素数１〜２４の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−に置き換わっていてもよく、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基で置換されていてもよい。
Ｙは、置換基を有していてもよいメチル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、該脂環式炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−、−ＳＯ_２−又は−ＣＯ−に置き換わっていてもよい。
Ｑ¹及びＱ²は、それぞれ独立して、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。］
［４］［１］〜［３］のいずれかに記載の塩と酸不安定基を有する樹脂とを含有するレジスト組成物。
［５］（１）［４］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) (hereinafter, may be referred to as a salt (I). Further, the side of the salt (I) having a positive charge may be referred to as a “cation (I)”. ).

[In formula (I),
R ¹ and R ² independently represent 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−. It may be replaced.
m and n independently represent 1 or 2, respectively. when m is 2, two R ¹ may be the same or different, when n is 2, the two R ² are same or different.
X represents an oxygen atom or a sulfur atom.
Ar represents an aromatic hydrocarbon group having 6 to 36 carbon atoms having an electron-withdrawing group or a heteroaromatic hydrocarbon group having 6 to 36 carbon atoms having an electron-withdrawing group.
A ⁻ represents a halide ion, a hydroxyd ion or an organic anion. ]
[2] The salt according to [1], wherein the organic anion is an organic sulfonic acid anion.
[3] The salt according to [1] or [2], wherein the organic anion is an anion represented by the formula (IA).

[In the formula (IA), L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and -CH _2- contained in the saturated hydrocarbon group is -O- or -CO-. The hydrogen atom contained in the saturated hydrocarbon group may be replaced with a fluorine atom or a hydroxy group.
Y represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a methyl group which may have a substituent or a substituent, and is contained in the alicyclic hydrocarbon group. CH ₂ - is, -O -, - SO ₂ - or -CO- may be replaced with.
Q ¹ and Q ² independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. ]
[4] A resist composition containing the salt according to any one of [1] to [3] and a resin having an acid unstable group.
[5] A step of applying the resist composition according to (1) and [4] onto a substrate.
(2) A step of drying the applied composition to form a composition layer,
(3) Step of exposing the composition layer,
A method for producing a resist pattern, which comprises a step of (4) heating the composition layer after exposure and (5) a step of developing the composition layer after heating.

Provided are a salt capable of producing a resist pattern with good CD uniformity (CDU) and a resist composition containing the salt.

As used herein, the term "(meth) acrylic monomer" means at least one type of monomer having a structure of _{"CH 2} = CH-CO-" or "CH ₂ = C (CH _{3) -CO-".} do. 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.

<Salt represented by formula (I)>
Ar represents an aromatic hydrocarbon group having an electron-withdrawing group or a heteroaromatic hydrocarbon group with an electron-withdrawing group. The aromatic hydrocarbon group or heteroaromatic hydrocarbon group usually has 6 to 36 carbon atoms, preferably 6 to 24 carbon atoms, and more preferably 6 to 18 carbon atoms. Ar is preferably an aromatic hydrocarbon group.
The aromatic hydrocarbon group includes a phenyl group, a naphthyl group, an anthryl group, a phenanthonyl group, a trill group, a xylyl group, a cumyl group, a dimethylphenyl group, a trimethylphenyl group, an ethylphenyl group, a propylphenyl group, a butylphenyl group and a biphenyl group. An aryl group having 6 to 36 carbon atoms such as a group, a triphenyl group, an indenyl group, a tetrahydronaphthyl group, a p-adamantylphenyl group, a phenanthryl group, a 2,6-diethylphenyl group, and a 2-methyl-6-ethylphenyl group. Can be mentioned.
Examples of the hetero atom include a nitrogen atom, an oxygen atom, and a sulfur atom.
Examples of the heteroaromatic hydrocarbon group include a frill group and a thiophenyl group.
Examples of the electron-withdrawing group include a halogen group, a cyano group and a nitro group, preferably a halogen group or a cyano group, and more preferably a fluoro group or a cyano group.

Examples of the hydrocarbon group represented by R ¹ and R ² include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these.
The alkyl group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, a 2-ethylhexyl group and an octyl group. , Nonyl group, decyl group, undecyl group, dodecyl group and the like.
The alicyclic hydrocarbon group may be either a monocyclic group or a polycyclic group, and the monocyclic alicyclic hydrocarbon group includes a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group and a methylcyclohexyl group. , Cycloalkyl group having 3 to 12 carbon atoms such as dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, cycloheptyl group and cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a 2-alkyladamantan-2-yl group, a 1- (adamantan-1-yl) alkane-1-yl group, and a norbornyl group. Examples thereof include a methylnorbornyl group and an isobornyl group.
Examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group.
Examples of the group formed by the combination include an aralkyl group, and examples thereof include an aralkyl group having 7 to 12 carbon atoms such as a benzyl group and a phenethyl group.
_{The groups in which -CH 2-} contained in the hydrocarbon group is replaced with -O- or -CO- include a methoxy group, an ethoxy group, a butoxy group, an acetyl group, a methoxycarbonyl group, an acetyloxy group, and a butoxycarbonyloxy group. , Benoxyloxy group and the like.

m is preferably 2.
n is preferably 2.
Of m and n, at least one is preferably 2, and more preferably both m and n are 2.
R ¹ is preferably a hydrogen atom.
R ² is preferably a hydrogen atom.
R ¹ and R ² are preferably the same group, and more preferably both hydrogen atoms.
Ar is preferably an aromatic hydrocarbon group having 6 to 24 carbon atoms having an electron-withdrawing group, more preferably an aromatic hydrocarbon group with 6 to 18 carbon atoms having an electron-withdrawing group, and electron-withdrawing. A phenyl group having a group or a naphthyl group having an electron-withdrawing group is more preferable, and a phenyl group having a fluoro group or a cyano group or a naphthyl group having a fluoro group or a cyano group is particularly preferable.

Examples of the cation (I) include the following cations and the like.

Among them, the formula (I-c-1), the formula (I-c-2), the formula (I-c-3), the formula (I-c-9), the formula (I-c-10), the formula ( I-c-12), formula (I-c-17), formula (I-c-18), formula (I-c-19) and cations represented by formula (I-c-25) are preferable. The cations represented by the formulas (I-c-1), (I-c-10), (I-c-12), and (I-c-17) are more preferable.

［式（Ｉ−Ａ）中、Ｌ^b1は、炭素数１〜２４の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−に置き換わっていてもよく、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基で置換されていてもよい。
Ｙは、置換基を有していてもよいメチル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、該脂環式炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−、−ＳＯ_２−又は−ＣＯ−に置き換わっていてもよい。
Ｑ¹及びＱ²は、それぞれ独立して、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。］ A ⁻ represents a monovalent anion, and specifically, a halide ion, a hydroxide ion, an organic sulfonic acid anion, an organic sulfonylimide anion, an organic sulfonylmethide anion, an alkoxide anion, a phenoxide anion, a carboxylic acid anion, and the like. Organic anion of.
A ⁻ is preferably a halide ion or an organic anion, more preferably an organic sulfonic acid anion or a carboxylic acid anion, and further preferably an organic sulfonic acid anion.
The organic sulfonic acid anion is preferably an organic sulfonic acid anion having a fluorine atom, and more preferably an anion represented by the formula (IA).

[In the formula (IA), L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and -CH _2- contained in the saturated hydrocarbon group is -O- or -CO-. The hydrogen atom contained in the saturated hydrocarbon group may be replaced with a fluorine atom or a hydroxy group.
Y represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a methyl group which may have a substituent or a substituent, and is contained in the alicyclic hydrocarbon group. CH ₂ - is, -O -, - SO ₂ - or -CO- may be replaced with.
Q ¹ and Q ² independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. ]

The perfluoroalkyl group of Q ¹ and Q ^2, a trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, a perfluoro sec- butyl group, perfluoro-tert- butyl group, perfluoropentyl group, and a perfluoro Hexyl groups and the like can be mentioned.
Independently, Q ¹ and Q ² are preferably a fluorine atom or a trifluoromethyl group, and more preferably a fluorine atom.
Q ¹ and Q ² are preferably the same group, and more preferably both are fluorine atoms.

Examples of the divalent saturated hydrocarbon group of L ^b1 include a linear alkanediyl group, a branched alkanediyl group, and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group. It may be a group formed by combining two or more of the groups.
Specifically, methylene group, ethylene group, propane-1,3-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, Nonan-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 and heptadecane-1,17-diyl group. Alcandiyl group;
Ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane- Branched alkanediyl groups such as 1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group;
Monocyclic 2 which is a cycloalkanediyl group such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclooctane-1,5-diyl group, etc. Valuable alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbons such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, and adamantane-2,6-diyl group. The group etc. can be mentioned.

The _{group in which -CH 2-} contained in the divalent saturated hydrocarbon group of ^{L b1} is replaced with -O- or -CO- is represented by any of the formulas (b1-1) to (b1-3). The group to be used is mentioned.
In equations (b1-1) to (b1-3), * represents a bond with −Y.

式（ｂ１−１）中、
Ｌ^b2は、単結合又は炭素数１〜２２の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b3は、単結合又は炭素数１〜２２の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよく、該飽和炭化水素基に含まれるメチレン基は、−Ｏ−又は−ＣＯ−に置き換わっていてもよい。
ただし、Ｌ^b2とＬ^b3との炭素数合計は、２２以下である。
式（ｂ１−２）中、
Ｌ^b４は、単結合又は炭素数１〜２２の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b５は、単結合又は炭素数１〜２２の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよく、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
ただし、Ｌ^b4とＬ^b5との炭素数合計は、２２以下である。
式（ｂ１−３）中、
Ｌ^b6は、単結合又は炭素数１〜２３の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
Ｌ^b7は、単結合又は炭素数１〜２３の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよく、該飽和炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−に置き換わっていてもよい。
ただし、Ｌ^b6とＬ^b7との炭素数合計は、２３以下である。

In equation (b1-1),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated hydrocarbon group may be substituted. The methylene group contained in the hydrocarbon group may be replaced with -O- or -CO-.
However, the total number of carbon atoms of ^{L b2} and L ^{b3 is 22 or less.}
In equation (b1-2),
L ^b4 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated hydrocarbon group may be substituted. The methylene group contained in the hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
However, the total number of carbon atoms of ^{L b4} and L ^{b5 is 22 or less.}
In equation (b1-3),
L ^b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
L ^b7 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated hydrocarbon group may be substituted. _{-CH 2-} contained in the hydrocarbon group may be replaced with -O- or -CO-.
However, the total number of carbon atoms of ^{L b6} and L ^{b7 is 23 or less.}

In the formulas (b1-1) to (b1-3), when -CH _2- contained in the saturated hydrocarbon group is replaced with -O- or -CO-, the number of carbon atoms before the replacement is used. Let it be the number of carbon atoms of the saturated hydrocarbon group.
Examples of the divalent saturated hydrocarbon group include those similar to the divalent saturated hydrocarbon group of ^{L b1.}

L ^b2 is preferably a single bond.
L ^b3 is preferably an alkanediyl group having 1 to 4 carbon atoms.
L ^b4 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b6 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b7 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. _{, -CH 2-} contained in the saturated hydrocarbon group may be replaced with -O- or -CO-.

The _{group in which -CH 2-} contained in the divalent saturated hydrocarbon group of ^{L b1} is replaced with -O- or -CO- is a group represented by the formula (b1-1) or the formula (b1-3). Is preferable.

式（ｂ１−４）中、
Ｌ^b8は、単結合又は炭素数１〜２２の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
式（ｂ１−５）中、
Ｌ^b9は、炭素数１〜２０の２価の飽和炭化水素基を表す。
Ｌ^b10は、単結合又は炭素数１〜１９の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b9及びＬ^b10の合計炭素数は２０以下である。
式（ｂ１−６）中、
Ｌ^b11は、炭素数１〜２１の２価の飽和炭化水素基を表す。
Ｌ^b12は、単結合又は炭素数１〜２０の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b11及びＬ^b12の合計炭素数は２１以下である。
式（ｂ１−７）中、
Ｌ^b13は、炭素数１〜１９の２価の飽和炭化水素基を表す。
Ｌ^b14は、単結合又は炭素数１〜１８の２価の飽和炭化水素基を表す。
Ｌ^b15は、単結合又は炭素数１〜１８の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b13、Ｌ^b14及びＬ^b15の合計炭素数は１９以下である。
式（ｂ１−８）中、
Ｌ^b16は、炭素数１〜１８の２価の飽和炭化水素基を表す。
Ｌ^b17は、炭素数１〜１８の２価の飽和炭化水素基を表す。
Ｌ^b18は、単結合又は炭素数１〜１７の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b16、Ｌ^b17及びＬ^b18の合計炭素数は１９以下である。 Examples of the formula (b1-1) include groups represented by the formulas (b1-4) to (b1-8). In equations (b1-4) to (b1-8), * represents a bond with −Y.

In equation (b1-4),
L ^b8 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
In equation (b1-5),
L ^b9 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms.
L ^b10 represents a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total number of carbon atoms of ^{L b9} and L ^{b10 is 20 or less.}
In equation (b1-6),
L ^b11 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b12 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total number of carbon atoms of ^{L b11} and L ^{b12 is 21 or less.}
In equation (b1-7),
L ^b13 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.
L ^b14 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b15 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total number of carbon atoms of ^{L b13} , L ^b14 and L ^{b15 is 19 or less.}
In equation (b1-8),
L ^b16 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b17 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b18 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total number of carbon atoms of ^{L b16} , L ^b17 and L ^{b18 is 19 or less.}

L ^b8 is preferably an alkanediyl group having 1 to 4 carbon atoms.
L ^b9 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b10 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b11 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b12 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b13 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b14 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b15 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b16 preferably represents a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b17 preferably represents a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b18 preferably represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and more preferably represents a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.

式（ｂ１−９）中、
Ｌ^b19は、単結合又は炭素数１〜２３の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b20は、単結合又は炭素数１〜２３の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子、ヒドロキシ基又はアシルオキシ基に置換されていてもよい。該アシルオキシ基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−に置き換わっていてもよく、該アシルオキシ基に含まれる水素原子は、ヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b19及びＬ^b20の合計炭素数は２３以下である。
式（ｂ１−１０）中、
Ｌ^b21は、単結合又は炭素数１〜２１の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b22は、単結合又は炭素数１〜２１の２価の飽和炭化水素基を表す。
Ｌ^b23は、単結合又は炭素数１〜２１の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子、ヒドロキシ基又はアシルオキシ基に置換されていてもよい。該アシルオキシ基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−に置き換わっていてもよく、該アシルオキシ基に含まれる水素原子は、ヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b21、Ｌ^b22及びＬ^b23の合計炭素数は２１以下である。
式（ｂ１−１１）中、
Ｌ^b24は、単結合又は炭素数１〜２０の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b25は、炭素数１〜２１の２価の飽和炭化水素基を表す。
Ｌ^b26は、単結合又は炭素数１〜２０の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子、ヒドロキシ基又はアシルオキシ基に置換されていてもよい。該アシルオキシ基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−に置き換わっていてもよく、該アシルオキシ基に含まれる水素原子は、ヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b24、Ｌ^b25及びＬ^b26の合計炭素数は２１以下である。 Examples of the formula (b1-3) include groups represented by the formulas (b1-9) to (b1-11), respectively. In formulas (b1-9) to (b1-11), * represents a bond with −Y.

In equation (b1-9),
L ^b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b20 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxy group or an acyloxy group. .. _{-CH 2-} contained in the acyloxy group may be replaced with -O- or -CO-, and the hydrogen atom contained in the acyloxy group may be replaced with a hydroxy group.
However, the total number of carbon atoms of ^{L b19} and L ^{b20 is 23 or less.}
In equation (b1-10),
L ^b21 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b22 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b23 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxy group or an acyloxy group. .. _{-CH 2-} contained in the acyloxy group may be replaced with -O- or -CO-, and the hydrogen atom contained in the acyloxy group may be replaced with a hydroxy group.
However, the total carbon number of ^{L b21} , L ^b22 and L ^{b23 is 21 or less.}
In equation (b1-11),
L ^b24 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b25 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b26 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxy group or an acyloxy group. .. _{-CH 2-} contained in the acyloxy group may be replaced with -O- or -CO-, and the hydrogen atom contained in the acyloxy group may be replaced with a hydroxy group.
However, L ^b24, the total number of carbon atoms of L ^b25 and L ^b26 is 21 or less.

In the formulas (b1-10) and (b1-11), when the hydrogen atom contained in the saturated hydrocarbon group is substituted with an acyloxy group, the number of carbon atoms of the acyloxy group, CO and O in the ester bond The number of carbon atoms of the saturated hydrocarbon group is taken into consideration, including the number of carbon atoms of the saturated hydrocarbon group.

Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, a cyclohexylcarbonyloxy group, an adamantylcarbonyloxy group and the like.
Examples of the acyloxy group having a substituent include an oxoadamantylcarbonyloxy group, a hydroxyadamantylcarbonyloxy group, an oxocyclohexylcarbonyloxy group, a hydroxycyclohexylcarbonyloxy group and the like.

Among the groups represented by the formula (b1-1), the groups represented by the formula (b1-4) include the following. * Represents a bond with -Y.

Among the groups represented by the formula (b1-1), the groups represented by the formula (b1-5) include the following. * Represents a bond with -Y.

Among the groups represented by the formula (b1-1), the groups represented by the formula (b1-6) include the following. * Represents a bond with -Y.

Among the groups represented by the formula (b1-1), the groups represented by the formula (b1-7) include the following. * Represents a bond with -Y.

Among the groups represented by the formula (b1-1), the groups represented by the formula (b1-8) include the following. * Represents a bond with -Y.

Examples of the group represented by the formula (b1-2) include the following. * Represents a bond with -Y.

Among the groups represented by the formula (b1-3), the groups represented by the formula (b1-9) include the following. * Represents a bond with -Y.

Among the groups represented by the formula (b1-3), the groups represented by the formula (b1-10) include the following. * Represents a bond with -Y.

Among the groups represented by the formula (b1-3), the groups represented by the formula (b1-11) include the following. * Represents a bond with -Y.

The alicyclic hydrocarbon group having 3 to 18 carbon atoms represented by Y may be either a monocyclic ring or a polycyclic ring, or may be a spiro ring.
_{When -CH 2-} contained in an alicyclic hydrocarbon group having 3 to 18 carbon atoms represented by Y is replaced by -O-, -SO _2- or -CO-, only one _{-CH 2- is replaced.} It may be a plurality of two or more.
Examples of the alicyclic hydrocarbon group having 3 to 18 carbon atoms represented by Y include groups represented by the formulas (Y1) to (Y38).

It is preferably a group represented by any of the formulas (Y1) to (Y20), the formula (Y30) and the formula (Y31), and more preferably the formula (Y11), the formula (Y15), the formula (Y16), It is a group represented by the formula (Y19), the formula (Y30) and the formula (Y31), and more preferably a group represented by the formula (Y11), the formula (Y15) and the formula (Y30).

Examples of the substituent of the alicyclic hydrocarbon group of Y include a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms which may have a hydroxy group, and an alicyclic hydrocarbon group having 3 to 16 carbon atoms. , An alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, an acyl group having 2 to 4 carbon atoms, a glycidyloxy group or-(CH ₂ ) _ja. during ^{_{'-O-CO-R b1'}} group (wherein, R ^{b1 'is} an alkyl group having 1 to 16 carbon atoms, an aromatic alicyclic hydrocarbon group or a C6-18 3 to 16 carbon atoms carbide It represents a hydrogen group. Ja'represents an integer of 0 to 4) and the like.

Examples of the alkyl group having a hydroxy group include a hydroxymethyl group and a hydroxyethyl group.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group.
Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group and a p-adamantylphenyl group; a tolyl group, a xylyl group, a cumenyl group, a mesityl group and a biphenyl group. Examples thereof include an aryl group such as a group, a phenanthryl group, a 2,6-diethylphenyl group and 2-methyl-6-ethylphenyl.
Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group and a naphthylethyl group.
Examples of the acyl group include an acetyl group, a propionyl group and a butyryl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

The substituents that Y may have are a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms which may have a hydroxy group, an aromatic hydrocarbon group having 6 to 18 carbon atoms, and-(. CH _{2) niv} is preferably ^{'-O-CO-R b1'} group, and more preferably a halogen atom and hydroxy group.

Examples of Y include the following.

Y is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and more preferably an adamantyl group which may have a substituent (constituting these groups). -CH _2- may be replaced with -O-, -SO2- or -CO-) More preferably, it is an adamantyl group, a hydroxyadamantyl group or an oxoadamantyl group or a group represented by the following.

Examples of the anion represented by the formula (IA) include anions represented by the formulas (IA-1) to (IA-49) [hereinafter, "depending on the formula number". It may be called "anion (IA-1)" or the like. ]. Among them, formulas (IA-1) to formulas (IA-4), formulas (IA-9), formulas (IA-10), formulas (IA-24) to formulas (I). An anions represented by any of −A-29), formula (IA-37), formulas (IA-40) to formulas (IA-43) are preferable.

Here, R ^{i2 to} R ⁱ⁷ are, for example, an alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group.
R ⁱ⁸ is, for example, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 5 to 12 carbon atoms, or a combination thereof. It is a group formed, more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group.
L ⁴⁴ is a single bond or an alkanediyl group having 1 to 4 carbon atoms.
Q ¹ and ^{Q 2} are the same as above.

As the anion represented by the formula (IA), the anions represented by the formulas (Ia-1) to (Ia-22) are preferable.

Examples of the organic sulfonylimide anion include the following.

Examples of the anion represented by the formula (IA) include formulas (Ia-1) to (Ia-3), formulas (Ia-7) to formulas (Ia-12), and formulas (Ia-17) to formulas (Ia-17). The anion represented by any of the formulas (Ia-19) and (Ia-22) is preferable, and the anion is represented by any of the formulas (Ia-2), (Ia-3) and (Ia-12). Anions are more preferred.

Examples of the salt (I) include the salts shown in Tables 1 and 2. In Table 1, for example, the salt (I-1) is the salt shown below.

Examples of the salt represented by the formula (I) include salt (I-1), salt (I-2), salt (I-4), salt (I-5), salt (I-6), and salt (I). -7), salt (I-8), salt (I-10), salt (I-11), salt (I-12), salt (I-13), salt (I-14), salt (I-) 16), salt (I-17), salt (I-18), salt (I-19), salt (I-20), salt (I-22), salt (I-23), salt (I-24) ), Salt (I-25), Salt (I-26), Salt (I-28), Salt (I-29), Salt (I-30), Salt (I-31), Salt (I-32) , Salt (I-34), Salt (I-35), Salt (I-36), Salt (I-37), Salt (I-38), Salt (I-40), Salt (I-41), Salt (I-42), salt (I-43), salt (I-44), salt (I-46), salt (I-47), salt (I-48), salt (I-49), salt (I-50), salt (I-52), salt (I-53), salt (I-54), salt (I-55), salt (I-56), salt (I-58), salt ( I-59), salt (I-60), salt (I-61), salt (I-62), salt (I-63), salt (I-64), salt (I-65), salt (I) -66), salt (I-67), salt (I-68), salt (I-69), salt (I-70), salt (I-71), salt (I-72), salt (I-) 73), salt (I-74), salt (I-75), salt (I-76), salt (I-77), salt (I-78), salt (I-79), salt (I-80) ), Salt (I-81), Salt (I-82), Salt (I-83), Salt (I-84), Salt (I-85), Salt (I-86), Salt (I-87) , Salt (I-88), Salt (I-89), Salt (I-90), Salt (I-91), Salt (I-92), Salt (I-93), Salt (I-94), Salt (I-95), salt (I-96), salt (I-97), salt (I-98), salt (I-99) and salt (I-100) are preferred.

（式中、Ｒ^１、Ｒ^２、Ａｒ、Ｘ、ｎ、ｍ及びＡ⁻は、前記と同義である。）
反応温度は通常、２０℃〜２００℃の範囲内である。
触媒としては、酢酸銅（ＩＩ）等が挙げられる。
溶剤としては、クロロホルム等が挙げられる。 The salt (I) can be produced by reacting a salt represented by the formula (Ia) with a compound represented by the formula (Ib) in a solvent in the presence of a catalyst.

(In the formula, R ¹ , R ² , Ar, X, n, m and A ⁻ have the same meanings as described above.)
The reaction temperature is usually in the range of 20 ° C to 200 ° C.
Examples of the catalyst include copper acetate (II) and the like.
Examples of the solvent include chloroform and the like.

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

（式中、Ａｒ、Ｑ¹、Ｑ²、Ｌ^b1及びＹは、前記と同義である。）
反応温度は通常、５℃〜６０℃の範囲内である。
溶剤としては、クロロホルム等が挙げられる。 Among the salts represented by the formula (IA), the salt in which A ⁻ is an anion represented by the formula (IA) (the salt represented by the following formula (I1-a)) is the salt represented by the formula (I1). It can be produced by reacting the salt represented by −c) with the salt represented by the formula (I1-d) in a solvent.

(In the equation, Ar, Q ¹ , Q ² , L ^{b 1} and Y are synonymous with the above.)
The reaction temperature is usually in the range of 5 ° C to 60 ° C.
Examples of the solvent include chloroform and the like.

Examples of the salt represented by the formula (I1-d) include compounds represented by the following formula.

The salt represented by the formula (I1-c) is produced by reacting the salt represented by the formula (I1-e) with the compound represented by the formula (I1-f) in a solvent such as chloroform. You can also do it.
The reaction temperature is usually in the range of 5 ° C to 60 ° C.

反応温度は通常、５℃〜６０℃の範囲内である。
酸としては、硫酸、酢酸、無水酢酸等が挙げられる。 The salt represented by the formula (I1-e) has an odor after reacting the compound represented by the formula (I1-g) with the compound represented by the formula (I1-h) in the presence of an acid. It can also be produced by treating with an aqueous sodium bromide solution.

The reaction temperature is usually in the range of 5 ° C to 60 ° C.
Examples of the acid include sulfuric acid, acetic acid, acetic anhydride and the like.

Examples of the compound represented by the formula (I1-g) include compounds represented by the following formula.

<Resist composition>
The resist composition contains a resin having an acid unstable group (hereinafter sometimes referred to as "resin (A)") and a salt represented by the formula (I). The salt represented by the formula (I) may contain two or more kinds.
The resist composition may contain an acid generator known in the field of resist (hereinafter, may be referred to as "acid generator (B)"). The resist composition preferably contains a quencher (hereinafter sometimes referred to as "quencher (C)") and preferably contains a solvent (hereinafter sometimes referred to as "solvent (D)"). The content of the salt (I) is preferably 1 to 20% by mass, more preferably 3 to 15% by mass, based on the resin (A).

<Acid generator (B)>
As the acid generator (B), a known acid generator can be used, and it may be an ionic acid generator or a nonionic acid generator. Preferably, it is an ionic acid generator. Examples of the ionic acid generator include an ionic acid generator composed of a combination of a known cation and a known anion.

Examples of the acid generator (B) include organic sulfonic acids and organic sulfonium salts. For example, the acid generation described in JP2013-68914, JP2013-3155, and JP2013-1905. Agents and the like can be mentioned. Specific examples thereof include salts represented by any of the formulas (B1-1) to (B1-40). Of these, those containing an arylsulfonium cation are preferable, and formulas (B1-1), formulas (B1-2), formulas (B1-3), formulas (B1-6), formulas (B1-7), and formulas (B1-11) are preferable. ), Equation (B1-12), Equation (B1-13), Equation (B1-14), Equation (B1-20), Equation (B1-21), Equation (B1-22), Equation (B1-23). , Equation (B1-24), Equation (B1-25), Equation (B1-26), Equation (B1-29), Equation (B1-31), Equation (B1-32), Equation (B1-33), Any of formula (B1-34), formula (B1-35), formula (B1-36), formula (B1-37), formula (B1-38), formula (B1-39) or formula (B1-40) The salt represented by is more preferable.

The acid generator (B) may contain two or more kinds.
The content of the acid generator (B) is preferably 1 to 20% by mass, more preferably 3 to 15% by mass, based on the resin (A).
In the resist composition, when the salt (I) and the acid generator (B) are used as the acid generator, the contents of the salt (I) and the acid generator (B) are preferable with respect to the resin (A). Is 1.5% by mass or more (more preferably 3% by mass or more), preferably 40% by mass or less (more preferably 35% by mass or less).

<Resin (A)>
The resin (A) has a structural unit having an acid unstable group (hereinafter, may be referred to as “structural unit (a1)”). The resin (A) preferably further contains a structural unit other than the structural unit (a1). Structural units other than the structural unit (a1) include structural units having no acid-labile group (hereinafter sometimes referred to as "structural unit (s)"), structural units (a1), and structural units other than the structural unit (s). Examples thereof include structural units (hereinafter sometimes referred to as “structural units (t)”) and other structural units derived from monomers known in the art.

［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、炭素数３〜２０の脂環式炭化水素基又はこれらを組み合わせた基を表すか、Ｒ^a1及びＲ^a2は互いに結合してそれらが結合する炭素原子とともに炭素数３〜２０の２価の脂環式炭化水素基を形成する。
ｎａは、０又は１を表す。
＊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’は互いに結合してそれらが結合する炭素原子及びＸ^ａ２とともに炭素数３〜２０の２価の複素環基を形成し、該炭化水素基及び該２価の複素環基に含まれる−ＣＨ₂−は、−Ｏ−又は−Ｓ−で置き換わってもよい。
Ｘ^ａ２は、酸素原子又は硫黄原子を表す。
＊は結合手を表す。］ <Structural unit (a1)>
The structural unit (a1) is derived from a monomer having an acid unstable group (hereinafter, may be referred to as “monomer (a1)”).
The acid unstable group contained in the resin (A) is preferably a group represented by the formula (1) and / or a group represented by the formula (2).

[In the formula (1), R ^{a1 to} R ^a3 independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a group combining these groups, or R. ^a1 and R ^a2 are bonded to each other to form a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.
na represents 0 or 1.
* Represents a bond. ]

[In the 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. Represented, R ^a2'and R ^a3' are bonded to each other to form a divalent heterocyclic group having 3 to 20 ^{carbon atoms together with the carbon atom and X a2 to which they are bonded, and the hydrocarbon group and the divalent} _{-CH 2} − contained in the heterocyclic group may be replaced with −O − or −S−.
X ^a2 represents an oxygen atom or a sulfur atom.
* Represents a bond. ]

アルキル基と脂環式炭化水素基とを組み合わせた基としては、例えば、メチルシクロヘキシル基、ジメチルシクロへキシル基、メチルノルボルニル基、シクロヘキシルメチル基、アダマンチルメチル基、ノルボルニルエチル基等が挙げられる。
ｎａは、好ましくは０である。 ^Examples of the alkyl group of R ^{a1 to} R a3 include a methyl group, an ethyl group, a propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group and the like.
The alicyclic hydrocarbon groups of R ^{a1 to} R ^a3 may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups (* indicates a bond). The alicyclic hydrocarbon groups of R ^{a1 to} R ^a3 are preferably alicyclic hydrocarbon groups having 3 to 16 carbon atoms.

Examples of the group in which the alkyl group and the alicyclic hydrocarbon group are combined include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, a norbornylethyl group and the like. Can be mentioned.
na is preferably 0.

^{Examples of -C (R a1} ) (R ^a2 ) (R ^a3 ) in the case where R ^a1 and R a ² are bonded to each other to form a divalent alicyclic hydrocarbon group include the following groups. The divalent alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms. * Represents a bond with -O-.

Examples of the group represented by the formula (1) include a 1,1-dialkylalkoxycarbonyl group (a group in which R ^{a1 to} R ^a3 are alkyl groups in the formula (1), preferably a tert-butoxycarbonyl group), 2-. Alkyl adamantan-2-yloxycarbonyl group (in formula (1), R ^a1 , R ^a2 and the carbon atom to which they are bonded 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) and the like.

Ｒ^a1’及びＲ^a2’のうち、少なくとも１つは水素原子であることが好ましい。 Examples of the hydrocarbon group R ^{a1 '~R a3',} an alkyl group, an alicyclic hydrocarbon group, and a group formed by combining an aromatic hydrocarbon group and thereof.
Examples of the alkyl group and the alicyclic hydrocarbon group include the same as above.
The aromatic hydrocarbon group includes a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group, a tolyl group, a xsilyl group, a cumenyl group, a mesityl group and a biphenyl group. Examples thereof include an aryl group such as a group, a phenanthryl group, a 2,6-diethylphenyl group and 2-methyl-6-ethylphenyl.
^{Examples of the} divalent heterocyclic group formed by R ^a2'and R a3'bonding to each other together with the carbon atom and X to which they are bonded include the following groups. * Represents a bond.

Of R ^{a1 'and} R ^a2', it is preferable that at least one is a hydrogen atom.

Specific examples of the groups represented by the formula (2) include the following groups. * Represents a bond.

The monomer (a1) is preferably a monomer having an acid unstable group and an ethylenically unsaturated bond, and more preferably a (meth) acrylic monomer having an acid unstable group.

Among the (meth) acrylic monomers having an acid unstable group, those having an alicyclic hydrocarbon group having 5 to 20 carbon atoms are preferable. If the resin (A) having a structural unit derived from the monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group is used in the resist composition, the resolution of the resist pattern can be improved.

As the structural unit derived from the (meth) acrylic monomer having a group represented by the formula (1), the structural unit represented by the formula (a1-0) is preferably represented by the formula (a1-1). Examples thereof include a structural unit or a structural unit represented by the formula (a1-2). These may be used alone or in combination of two or more. In the present specification, the structural unit represented by the formula (a1-0), the structural unit represented by the formula (a1-1), and the structural unit represented by the formula (a1-2) are each structural unit (a1). −0), structural unit (a1-1) and structural unit (a1-2), monomer for inducing structural unit (a1-0), monomer for inducing structural unit (a1-1) and structural unit (a1-) The monomer that induces 2) may be referred to as a monomer (a1-0), a monomer (a1-1), and a monomer (a1-2), respectively.

［式（ａ１−０）中、
Ｌ^a01は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k01−ＣＯ−Ｏ−を表し、ｋ０１は１〜７のいずれかの整数を表し、＊はカルボニル基との結合手を表す。
Ｒ^a01は、水素原子又はメチル基を表す。
Ｒ^a02、Ｒ^a03及びＲ^a04は、それぞれ独立に、炭素数１〜８のアルキル基、炭素数３〜１８の脂環式炭化水素基又はこれらを組み合わせた基を表す。］

[In equation (a1-0),
L ^a01 represents an oxygen atom or _{^{* -O- (CH 2) k01 -CO}} -O- the stands, k01 represents an integer of 1-7, * represents a bond to a carbonyl group.
R ^a01 represents a hydrogen atom or a methyl group.
R ^a02 , R ^a03, and R ^a04 independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group combining these groups. ]

［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のいずれかの整数を表し、＊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、炭素数３〜１８の脂環式炭化水素基又はこれらを組み合わせることにより形成される基を表す。
ｍ１は０〜１４のいずれかの整数を表す。
ｎ１は０〜１０のいずれかの整数を表す。
ｎ１’は０〜３のいずれかの整数を表す。］

[In the formula (a1-1) and the formula (a1-2),
L ^a1 and L ^a2 independently represent −O− or ^* −O− (CH ₂ ) _k1 −CO−O−, k1 represents an integer of 1 to 7, and * represents −CO−. Represents a bond with.
R ^a4 and R ^a5 independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group formed by combining them.
m1 represents any integer from 0 to 14.
n1 represents any integer from 0 to 10.
n1'represents an integer of 0 to 3. ]

^La01 is preferably an oxygen atom or ^* -O- (CH ₂ ) _k01- CO-O- (where k01 is preferably an integer of 1 to 4, more preferably 1. ), More preferably an oxygen atom.
Examples of the alkyl group of R ^a02 , R ^a03 and R ^a04 , the alicyclic hydrocarbon group and the group combining these groups include the same groups as those mentioned in ^{R a1 to} R ^{a3 of the formula (1).}
The alkyl groups of R ^a02 , R ^a03 and R ^a04 preferably have 6 or less carbon atoms.
The alicyclic hydrocarbon groups of R ^a02 , R ^a03 and R ^a04 preferably have 8 or less carbon atoms, and more preferably 6 or less carbon atoms.
The group in which the alkyl group and the alicyclic hydrocarbon group are combined preferably has a total carbon number of 18 or less in combination with these alkyl groups and the alicyclic hydrocarbon group. Examples of such a group include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a methyladamantyl group, a cyclohexylmethyl group, a methylcyclohexylmethyl group, an adamantylmethyl group, a norbornylmethyl group and the like. Be done.
R ^a02 and R ^a03 are preferably alkyl groups having 1 to 6 carbon atoms, and more preferably methyl groups or ethyl groups.
^Ra04 is preferably an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 5 to 12 carbon atoms, and more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group.

L ^a1 and L ^a2 are preferably −O− or ^* −O− (CH ₂ ) _{k1 ′} −CO−O− (where k1 ′ is an integer of any of 1 to 4, and is preferable. Is 1.), More preferably −O−.
R ^a4 and R ^a5 are preferably methyl groups.
Examples of the alkyl group of R ^a6 and R ^a7 , the alicyclic hydrocarbon group, and the group combining these groups include the same groups as those listed in ^{R a1 to} R ^{a3 of the formula (1).}
The alkyl groups of R ^a6 and R ^a7 preferably have 6 or less carbon atoms.
The alicyclic hydrocarbon groups of R ^a6 and R ^a7 are preferably alicyclic hydrocarbon groups having 8 or less carbon atoms, and more preferably 6 or less alicyclic hydrocarbon groups.
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.

As the structural unit (a1-0), for example, a structural unit represented by any of the formulas (a1-0-1) to (a1-0-12) is preferable, and the structural units (a1-0-1) to The structural unit represented by any of the formulas (a1-0-10) is more preferable.

In the above structural units, structural units in which a methyl group is replaced by a hydrogen atom corresponding to R ^a01 may be mentioned as specific examples of the structural units (a1-0).

Examples of the monomer (a1-1) include the monomers described in JP-A-2010-204646. Among them, the monomers represented by any of the formulas (a1-1-1) to (a1-1-8) are preferable, and any one of the formulas (a1-1-1) to (a1-1-4) is preferable. The monomer represented by is more preferable.

Examples of the monomer (a1-2) include 1-methylcyclopentane-1-yl (meth) acrylate, 1-ethylcyclopentane-1-yl (meth) acrylate, and 1-methylcyclohexane-1-yl (meth). Acrylate, 1-ethylcyclohexane-1-yl (meth) acrylate, 1-ethylcycloheptan-1-yl (meth) acrylate, 1-ethylcyclooctane-1-yl (meth) acrylate, 1-isopropylcyclopentane-1 -Il (meth) acrylate, 1-isopropylcyclohexane-1-yl (meth) acrylate and the like can be mentioned. Monomers represented by any of formulas (a1-2-1) to (a1-2-12) are preferable, and formulas (a1-2-3), formulas (a1-2-4), and formulas (a1-) are preferable. The monomers represented by 2-9) and the formula (a1-2-10) are more preferable, and the monomers represented by the formulas (a1-2-3) and the formula (a1-2-9) are further preferable.

When the resin (A) contains a structural unit (a1-0) and / or a structural unit (a1-1) and / or a structural unit (a1-2), the total content of these is the total structure of the resin (A). It is usually 10 to 95 mol%, preferably 15 to 90 mol%, and more preferably 20 to 85 mol% with respect to the unit.

式（ａ１−５）中、
Ｒ^a8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。
Ｚ^a1は、単結合又は＊−（ＣＨ₂）_h3−ＣＯ−Ｌ⁵⁴−を表し、ｈ３は１〜４のいずれかの整数を表し、＊は、Ｌ⁵¹との結合手を表す。
Ｌ⁵¹、Ｌ⁵²、Ｌ⁵³及びＬ⁵⁴は、それぞれ独立に、−Ｏ−又は−Ｓ−を表す。
ｓ１は、１〜３のいずれかの整数を表す。
ｓ１’は、０〜３のいずれかの整数を表す。 The structural unit derived from the (meth) acrylic monomer having a group represented by the formula (2) is a structural unit represented by the formula (a1-5) (hereinafter referred to as “structural unit (a1-5)”). There is).

In equation (a1-5),
R ^a8 represents an alkyl group having 1 to 6 carbon atoms, a hydrogen atom or a halogen atom which may have a halogen atom.
Z ^a1 represents a single bond or * − (CH ₂ ) _h3 −CO−L ⁵⁴ −, h3 represents an integer of 1 to 4, and * represents a bond with ^{L 51.}
L ⁵¹ , L ⁵² , L ⁵³ and L ⁵⁴ independently represent -O- or -S-, respectively.
s1 represents an integer of 1 to 3.
s1'represents an integer of 0 to 3.

Examples of the halogen atom include a fluorine atom and a chlorine atom, and a fluorine atom is preferable.
Alkyl groups having 1 to 6 carbon atoms which may have a halogen atom include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, fluoromethyl group and trifluoromethyl. Group is mentioned.
In the formula (a1-5), R ^a8 represents a hydrogen atom, a methyl group or a trifluoromethyl group.
L ⁵¹ is preferably an oxygen atom.
Of L ⁵² and L ⁵³ , it is preferable that one is −O− and the other is −S−.
s1 is preferably 1.
s1'is preferably an integer of 0 to 2.
Z ^a1 is preferably a single bond or * -CH _2- CO-O-.

Examples of the monomer for deriving the structural unit (a1-5) include the monomers described in JP-A-2010-61117. Among them, the monomers represented by the formulas (a1-5-1) to (a1-5-2) are preferable, and the monomers represented by the formula (a1-5-1) or the formula (a1-5-2) are preferable. Is more preferable.

When the resin (A) has a structural unit (a1-5), the content thereof is preferably 1 to 50 mol%, more preferably 3 to 45 mol%, based on all the structural units of the resin (A). , 5-40 mol% is more preferred.

Further, as the structural unit (a1), the hydrogen atom bonded to the main chain of the following structural unit and the structural unit represented by the formulas (a1-4-4) to (a1-4-8) becomes a methyl group. Examples include replaced structural units.

樹脂（Ａ）が上記構造単位を含む場合、その含有率は、樹脂（Ａ）の全構造単位に対して、１０〜９５モル％が好ましく、１５〜９０モル％がより好ましく、２０〜８５モル％がさらに好ましい。

When the resin (A) contains the above structural units, the content thereof is preferably 10 to 95 mol%, more preferably 15 to 90 mol%, and 20 to 85 mol% with respect to all the structural units of the resin (A). % Is more preferable.

The structural unit (a) having an acid unstable group in the resin (A) includes a structural unit (a1-0), a structural unit (a1-1), a structural unit (a1-2), and a structural unit (a1-5). At least one or more selected from the group consisting of) is preferable, and at least two or more are more preferable, and combinations of structural units (a1-1) and structural units (a1-2), structural units (a1-1) and structural units (a1-1) The combination of a1-5) is even more preferable. The structural unit (a1) preferably includes the structural unit (a1-1).

<Structural unit (s)>
The structural unit (s) is derived from a monomer having no acid-labile group (hereinafter, may be referred to as “monomer (s)”). As the monomer for deriving the structural unit (s), a monomer having no acid unstable group known in the resist field can be used.
As the structural unit (s), a structural unit having a hydroxy group or a lactone ring and having no acid unstable group is preferable. A structure having a hydroxy group and no acid-labile group (hereinafter sometimes referred to as "structural unit (a2)") and / or a lactone ring and no acid-labile group. If a resin having a unit (hereinafter sometimes referred to as "structural unit (a3)") is used in the resist composition of the present invention, the resolution of the resist pattern and the adhesion to the substrate can be improved.

<Structural unit (a2)>
The hydroxy group contained in the structural unit (a2) may be an alcoholic hydroxy group or a phenolic hydroxy group.
When a resist pattern is produced from the resist composition of the present invention, when a high-energy ray such as a KrF excimer laser (248 nm), an electron beam or EUV (ultraviolet light) is used as an exposure light source, the structural unit (a2) is used. , It is preferable to use the structural unit (a2) having a phenolic hydroxy group. When an ArF excimer laser (193 nm) or the like is used, the structural unit (a2) is preferably a structural unit (a2) having an alcoholic hydroxy group, and more preferably a structural unit (a2-1). As the structural unit (a2), one type may be contained alone, or two or more types may be included.

［式（ａ２−０）中、
Ｒ^a30は、水素原子、ハロゲン原子又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、アクリロイルオキシ基又はメタクリロイルオキシ基を表す。
ｍａは０〜４のいずれかの整数を表す。ｍａが２以上の整数である場合、複数のＲ^a31は互いに同一であっても異なってもよい。］ Examples of the structural unit (a2) having a phenolic hydroxy group include a structural unit represented by the formula (a2-0) (hereinafter, may be referred to as “structural unit (a2-0)”).

[In equation (a2-0),
^Ra30 represents an alkyl group having 1 to 6 carbon atoms which may have a hydrogen atom, a halogen 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 acryloyloxy group or the like. Represents a methacryloyloxy group.
ma represents any integer from 0 to 4. When ma is an integer of 2 or more, the plurality of Ra ^31s may be the same or different from each other. ]

^Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom of Ra30 include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 1,1,1-trifluoroethyl group, and 1 , 1,2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 1,1,1,2,2-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3 , 3,4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 1,1,1,2,2,3,3,4,4-nonafluoropentyl group, n-pentyl group, n-hexyl Groups, n-perfluorohexyl group and the like can be mentioned. R ^a30 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and even more preferably a hydrogen atom or a methyl group.
^Examples of the alkoxy group of Ra31 include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group and a hexyloxy group. Of these, an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is even more preferable.
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 the like.
The ma is preferably 0, 1 or 2, more preferably 0 or 1, and even more preferably 0.

Examples of the monomer for inducing the structural unit (a2-0) include the monomers described in JP-A-2010-204634.
Among them, the structural unit (a2-0) is represented by the formula (a2-0-1), the formula (a2-0-2), the formula (a2-0-3) and the formula (a2-0-4), respectively. The structural unit represented by the formula (a2-0-1) or the formula (a2-0-2) is more preferable.

The resin (A) containing the structural unit (a2-0) undergoes a polymerization reaction using a monomer in which the phenolic hydroxy group of the monomer inducing the structural unit (a2-0) is protected with a protecting group, and then deprotected. It can be manufactured by processing. However, when performing the deprotection treatment, it is necessary to carry out the deprotection treatment so as not to significantly impair the acid unstable group of the structural unit (a1). Examples of such a protecting group include an acetyl group and the like.

When the resin (A) has a structural unit (a2-0) having a phenolic hydroxy group, the content thereof is preferably 5 to 95 mol%, preferably 10 to 95 mol%, based on the total structural units of the resin (A). 80 mol% is more preferable, and 15 to 80 mol% is even more preferable.

式（ａ２−１）中、
Ｌ^a3は、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k2−ＣＯ−Ｏ−を表し、
ｋ２は１〜７のいずれかの整数を表す。＊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のいずれかの整数を表す。 Examples of the structural unit (a2) having an alcoholic hydroxy group include a structural unit represented by the formula (a2-1) (hereinafter, may be referred to as “structural unit (a2-1)”).

In equation (a2-1),
^La3 represents −O− or ^* −O− (CH ₂ ) _k2 −CO−O−.
k2 represents any integer from 1 to 7. * Represents a bond with -CO-.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 independently represent a hydrogen atom, a methyl group or a hydroxy group, respectively.
o1 represents any integer from 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 of 1 to 4) , More preferably -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.

Examples of the structural unit (a2-1) include structural units derived from the monomers described in JP-A-2010-204646. The structural unit represented by any of the formulas (a2-1-1) to (a2-1-6) is preferable, and any of the formulas (a2-1-1) to (a2-1-4) is used. The structural unit represented is more preferable, and the structural unit represented by the formula (a2-1-1) or the formula (a2-1-3) is further preferable.

When the resin (A) contains the structural unit (a2-1), the content thereof is usually 1 to 45 mol%, preferably 1 to 40 mol%, based on all the structural units of the resin (A). Yes, more preferably 1 to 35 mol%, still more preferably 2 to 20 mol%.

<Structural unit (a3)>
The lactone ring of the structural unit (a3) may be a monocyclic ring such as β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, or a fused ring of a monocyclic lactone ring and another ring. But it may be. Preferably, a crosslinked ring containing a γ-butyrolactone ring, an adamantanane lactone ring or a γ-butyrolactone ring structure can be mentioned.

The structural unit (a3) is preferably a structural unit represented by the formula (a3-1), the formula (a3-2), the formula (a3-3) or the formula (a3-4). One of these may be contained alone, or two or more thereof may be contained.

［式（ａ３−１）中、
Ｌ^a4は、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７のいずれかの整数を表す。
）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a18は、水素原子又はメチル基を表す。
Ｒ^a21は炭素数１〜４の脂肪族炭化水素基を表す。
ｐ１は０〜５のいずれかの整数を表す。ｐ１が２以上のとき、複数のＲ^a21は互いに同一又は相異なる。
式（ａ３−２）中、
Ｌ^a5は、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７のいずれかの整数を表す。
）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a19は、水素原子又はメチル基を表す。
Ｒ^a22は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。
ｑ１は、０〜３のいずれかの整数を表す。ｑ１が２以上のとき、複数のＲ^a22は互いに同一又は相異なる。
式（ａ３−３）中、
Ｌ^a6は、−Ｏ−又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７のいずれかの整数を表す。
）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a20は、水素原子又はメチル基を表す。
Ｒ^a23は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。
ｒ１は、０〜３のいずれかの整数を表す。ｒ１が２以上のとき、複数のＲ^a23は互いに同一又は相異なる。
式（ａ３−４）中、
Ｒ^a24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^ａ２５は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表す。
Ｌ^a7は、−Ｏ−、^＊−Ｏ−Ｌ^a8−Ｏ−、^＊−Ｏ−Ｌ^a8−ＣＯ−Ｏ−、^＊−Ｏ−Ｌ^a8−ＣＯ−Ｏ−Ｌ^a9−ＣＯ−Ｏ−又は^＊−Ｏ−Ｌ^a8−Ｏ−ＣＯ−Ｌ^a9−Ｏ−を表す。
＊はカルボニル基との結合手を表す。
Ｌ^a8及びＬ^a9は、互いに独立に、炭素数１〜６のアルカンジイル基を表す。
ｗ１は、０〜８のいずれかの整数を表す。ｗ１が２以上のとき、複数のＲ^ａ２５は互いに同一であってもよく、異なってもよい。］

[In equation (a3-1),
^La4 represents −O− or ^* −O− (CH ₂ ) _k3 −CO−O− (k3 is an integer of any of 1 to 7.
) Represents a group. * Represents a bond with a carbonyl group.
R ^a18 represents a hydrogen atom or a methyl group.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents any integer from 0 to 5. When p1 is 2 or more, a plurality of Ra ^21s are the same or different from each other.
In equation (a3-2),
^La5 represents −O− or ^* −O− (CH ₂ ) _k3 −CO−O− (k3 is an integer of any of 1 to 7.
) Represents a group. * Represents a bond with a carbonyl group.
R ^a19 represents a hydrogen atom or a methyl group.
R ^a22 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
q1 represents any integer from 0 to 3. When q1 is 2 or more, a plurality of ^Ra22s are the same or different from each other.
In formula (a3-3),
^La6 represents −O− or ^* −O− (CH ₂ ) _k3 −CO−O− (k3 is an integer of any of 1 to 7.
) Represents a group. * Represents a bond with a carbonyl group.
R ^a20 represents a hydrogen atom or a methyl group.
R ^a23 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
r1 represents any integer from 0 to 3. When r1 is 2 or more, a plurality of ^Ra23s are the same or different from each other.
In formula (a3-4),
R ^a24 represents an alkyl group having 1 to 6 carbon atoms, a hydrogen atom or a halogen atom which may have a halogen atom.
^Ra25 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
L ^a7 is -O-, ^* -O-L ^a8- O-, ^* -O-L ^a8- CO-O-, ^* -O-L ^a8- CO-O-L ^a9- CO-O- or ^* Represents −O−L ^a8 −O−CO−L ^a9 −O−.
* Represents a bond with a carbonyl group.
^{La 8} and ^{La 9} represent an alkanediyl group having 1 to 6 carbon atoms independently of each other.
w1 represents any integer from 0 to 8. When w1 is 2 or more, the plurality of Ra ^25s may be the same or different from each other. ]

The aliphatic hydrocarbon groups of R ^a21 , R ^a22 and R ^a23 include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group and tert-butyl group. Can be mentioned.
Examples of the halogen atom of R ^a24 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
^Examples of the alkyl group of R a24 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group and an n-hexyl group. , It is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group.
Alkyl groups having a halogen atom of R ^a24 include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group and perfluoro. Examples thereof include a hexyl group, a trichloromethyl group, a tribromomethyl group, and a triiodomethyl group.

The ^{alkanediyl groups of La8} and ^La9 include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, and pentane-1,5. -Diyl group, hexane-1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1, Examples thereof include 4-diyl group and 2-methylbutane-1,4-diyl group.

In the formula (a3-1) ~ formula (a3-3), L ^a4 ~L ^a6 are each independently preferably, -O- or is either an integer k3 is 1 to 4 * -O- (CH ₂ ) _{A group represented by k3-} CO-O-, more preferably -O- and * -O-CH _2- CO-O-, still more preferably an oxygen atom.
R ^{a18 to} R ^a21 are preferably methyl groups.
R ^a22 and R ^a23 are each independently, preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are independently, preferably an integer of 0 to 2, and more preferably 0 or 1.

（式中、Ｒ^ａ２４、及びＬ^ａ７は、上記と同じ意味を表す。） In formula (a3-4)
R ^a24 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and further preferably a hydrogen atom or a methyl group.
L ^a7 is preferably -O- or ^* -O-L ^a8- CO-O-, and more preferably -O-, -O-CH ₂ -CO-O- or -O-C ₂ H. _4- CO-O-.
^Ra25 is preferably a carboxy group, a cyano group or a methyl group.
w1 is preferably an integer of 0 to 2, more preferably 0 or 1.
In particular, the formula (a3-4) is preferably the formula (a3-4)'.

(In the formula, ^Ra24 and ^La7 have the same meanings as above.)

Examples of the monomer for deriving the structural unit (a3) include the monomers described in JP-A-2010-204646, the monomers described in JP-A-2000-122294, and the monomers described in JP-A-2012-41274. Can be mentioned. The structural unit (a3) includes equations (a3-1-1) to (a3-1-4), equations (a3-2-1) to (a3-2-4), and equations (a3-3-3). 1) The structural unit represented by any of the formulas (a3-3-4) and the formulas (a3-4-1) to (a3-4-12) is preferable, and the formula (a3-1-1), It is represented by any of the formulas (a3-1-2), formulas (a3-2-3) to formulas (a3-2-4) and formulas (a3-4-1) to formulas (a3-4-12). The structural unit is more preferable, and the structural unit represented by any of the formulas (a3-4-1) to (a3-4-12) is more preferable, and the structural units represented by the formulas (a3-4-1) to (a3-4-1) are more preferable. The structural unit represented by any of 4-6) is even more preferable.

In the structural unit represented by the following formula (a3-4-1) ~ formula (a3-4-12), compound methyl group corresponding to R ^a24 is replaced by a hydrogen atom, the structural unit (a3-4 ) Can be given as a specific example.

When the resin (A) contains the structural unit (a3), the total content thereof is usually 5 to 70 mol%, preferably 10 to 65 mol%, based on all the structural units of the resin (A). , More preferably 10 to 60 mol%.
The contents of the structural unit (a3-1), the structural unit (a3-2), the structural unit (a3-3), and the structural unit (a3-4) are each relative to all the structural units of the resin (A). Therefore, 5 to 60 mol% is preferable, 5 to 50 mol% is more preferable, and 10 to 50 mol% is further preferable.

<Structural unit (t)>
As the structural unit (t), a structural unit having a halogen atom in addition to the structural unit (a2) and the structural unit (a3) (hereinafter, sometimes referred to as “structural unit (a4)”) and a non-eliminating hydrocarbon group are used. Examples thereof include a structural unit having a structure (hereinafter, may be referred to as a “structural unit (a5)”).

［式（ａ４−０）中、
Ｒ⁵は、水素原子又はメチル基を表す。
Ｌ⁴は、単結合又は２価の炭素数１〜４の脂肪族飽和炭化水素基を表す。
Ｌ³は、炭素数１〜８のペルフルオロアルカンジイル基又は炭素数３〜１２のペルフルオロシクロアルカンジイル基を表す。
Ｒ⁶は、水素原子又はフッ素原子を表す。］ Examples of the structural unit (a4) include a structural unit represented by the formula (a4-0).

[In equation (a4-0),
R ⁵ represents a hydrogen atom or a methyl group.
L ⁴ represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 4 carbon atoms.
L ³ represents a perfluoroalkanediyl group having 1 to 8 carbon atoms or a perfluorocycloalkanediyl group having 3 to 12 carbon atoms.
R ⁶ represents a hydrogen atom or a fluorine atom. ]

Examples of the divalent aliphatic saturated hydrocarbon group represented by L ⁴ include an alkanediyl group having 1 to 4 carbon atoms, for example, a methylene group, an ethylene group, a propane-1,3-diyl group, butane-1, A linear alkanediyl group such as a 4-diyl group, a linear alkanediyl group having a side chain of an alkyl group (particularly a methyl group, an ethyl group, etc.), an ethane-1,1-diyl group, Bifurcated alkanediyl groups such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group can be mentioned. Be done.

The perfluoroalkanediyl group of L ³ includes a difluoromethylene group, a perfluoroethylene group, a perfluoroethylfluoromethylene group, a perfluoropropane-1,3-diyl group, a perfluoropropane-1,2-diyl group, and a perfluoropropane-2,2. -Diyl group, perfluorobutane-1,4-diyl group, perfluorobutane-2,2-diyl group, perfluorobutane-1,2-diyl group, perfluoropentane-1,5-diyl group, perfluoropentane-2,2 -Diyl group, perfluoropentane-3,3-diyl group, perfluorohexane-1,6-diyl group, perfluorohexane-2,2-diyl group, perfluorohexane-3,3-diyl group, perfluoroheptane-1,7 -Diyl group, perfluoroheptane-2,2-diyl group, perfluoroheptane-3,4-diyl group, perfluoroheptane-4,4-diyl group, perfluorooctane-1,8-diyl group, perfluorooctane-2,2 -Diyl group, perfluorooctane-3,3-diyl group, perfluorooctane-4,4-diyl group and the like can be mentioned.
Examples of the perfluorocycloalkanediyl group of L ³ include a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, a perfluoroadamantandiyl group and the like.

L ⁴ is preferably a single bond, a methylene group or an ethylene group, and more preferably a single bond or a methylene group.
L ³ is preferably a perfluoroalkanediyl group having 1 to 6 carbon atoms, and more preferably a perfluoroalkanediyl group having 1 to 3 carbon atoms.

The structural unit (a4-0), a methyl group have structural units replaced by a hydrogen atom corresponding to R ⁵ in the structural unit and the following structural units shown below.

［式（ａ４−１）中、
Ｒ^a41は、水素原子又はメチル基を表す。
Ｒ^a42は、置換基を有していてもよい炭素数１〜２０の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ₂−は、−Ｏ−又は−ＣＯ−に置き換わっていてもよい。
Ａ^a41は、置換基を有していてもよい炭素数１〜６のアルカンジイル基又は式（ａ−ｇ１）で表される基を表す。

〔式（ａ−ｇ１）中、
ｓは０又は１を表す。
Ａ^a42及びＡ^a44は、それぞれ独立に、置換基を有していてもよい炭素数１〜５の２価の脂肪族炭化水素基を表す。
Ａ^a43は、単結合又は置換基を有していてもよい炭素数１〜５の２価の脂肪族炭化水素基を表す。
Ｘ^a41及びＸ^a42は、それぞれ独立に、−Ｏ−、−ＣＯ−、−ＣＯ−Ｏ−又は−Ｏ−ＣＯ−を表す。
ただし、Ａ^a42、Ａ^a43、Ａ^a44、Ｘ^a41及びＸ^a42の炭素数の合計は７以下である。〕
＊は結合手であり、右側の＊が−Ｏ−ＣＯ−Ｒ^a42との結合手である。］ Examples of the structural unit (a4) include a structural unit represented by the formula (a4-1).

[In equation (a4-1),
R ^a41 represents a hydrogen atom or a methyl group.
R ^a42 represents a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and −CH ₂ − contained in the hydrocarbon group may be replaced with −O− or −CO−. good.
A ^a41 represents an alkanediyl group having 1 to 6 carbon atoms which may have a substituent or a group represented by the formula (ag1).

[In the formula (ag1),
s represents 0 or 1.
A ^a42 and A ^a44 each independently represent a divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a substituent.
A ^a43 represents a divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a single bond or a substituent.
X ^a41 and X ^a42 independently represent -O-, -CO-, -CO-O- or -O-CO-, respectively.
However, the total number of carbon atoms of ^{A a42} , A ^a43 , A ^a44 , X ^a41 and X ^{a42 is 7 or less.} ]
* Is a bond, and * on the right is a bond with -O-CO-R ^a42 . ]

^Examples of the hydrocarbon group of R a42 include a chain type and a ring type aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these groups.
The chain-type and cyclic-type aliphatic hydrocarbon groups may have a carbon-carbon unsaturated bond, but chain-type and cyclic-type aliphatic saturated hydrocarbon groups are preferable. The aliphatic saturated hydrocarbon group is a fat formed by combining a linear or branched alkyl group and a monocyclic or polycyclic alicyclic hydrocarbon group, and an alkyl group and an alicyclic hydrocarbon group. Group hydrocarbon groups and the like can be mentioned.

芳香族炭化水素基としては、フェニル基、ナフチル基、アントリル基、ビフェニリル基、フェナントリル基及びフルオレニル基が挙げられる。 Chain-type aliphatic hydrocarbon groups include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group and n-decyl. Examples thereof include a group, an n-dodecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group and an n-octadecyl group. Cyclic aliphatic hydrocarbon groups include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* is a bond). Examples thereof include polycyclic aliphatic hydrocarbon groups such as (representing a hand).

Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a biphenylyl group, a phenanthryl group and a fluorenyl group.

［式（ａ−ｇ３）中、
Ｘ^a43は、酸素原子、カルボニル基、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ^a45は、少なくとも１つのハロゲン原子を有する炭素数１〜１７の脂肪族炭化水素基を表す。
＊は結合手を表す。］ Examples of R a42 include a halogen atom or a group represented by the formula ( ^{ag3) as a substituent.} Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.

[In the formula (ag3),
X ^a43 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ^a45 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms having at least one halogen atom.
* Represents a bond. ]

Examples of the aliphatic hydrocarbon group of A ^{a45 include} the same groups as those exemplified in ^{R a42.}
R ^a42 is preferably an aliphatic hydrocarbon group which may have a halogen atom, and more preferably an alkyl group having a halogen atom and / or an aliphatic hydrocarbon group having a group represented by the formula (ag3). ..
When R ^a42 is an aliphatic hydrocarbon group having a halogen atom, it is preferably an aliphatic hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, and further preferably having a carbon number of carbons. It is a perfluoroalkyl group of 1 to 6, and particularly preferably a perfluoroalkyl group having 1 to 3 carbon atoms. Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group and a perfluorooctyl group. Examples of the perfluorocycloalkyl group include a perfluorocyclohexyl group.
When R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula (ag3), the aliphatic hydrocarbon includes the number of carbon atoms contained in the group represented by the formula (ag3). The total carbon number of the group is preferably 15 or less, more preferably 12 or less. When the group represented by the formula (ag3) is used as a substituent, the number thereof is preferably one.

［式（ａ−ｇ２）中、
Ａ^a46は、ハロゲン原子を有していてもよい炭素数１〜１７の脂肪族炭化水素基を表す。
Ｘ^a44は、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ^a47は、ハロゲン原子を有していてもよい炭素数１〜１７の脂肪族炭化水素基を表す。
ただし、Ａ^a46、Ａ^a47及びＸ^a44の炭素数の合計は１８以下であり、Ａ^a46及びＡ^a47のうち、少なくとも一方は、少なくとも１つのハロゲン原子を有する。
＊はカルボニル基との結合手を表す。］ When R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula ( ^{ag3), R a42} is more preferably a group represented by the formula (ag2).

[In the formula (ag2),
A ^a46 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
X ^a44 represents a carbonyloxy group or an oxycarbonyl group.
A ^a47 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
However, the total number of carbon atoms of ^{A a46} , A ^a47 and X ^{a44 is 18 or less, and at least one of A a46} and A ^a47 has at least one halogen atom.
* Represents a bond with a carbonyl group. ]

The aliphatic hydrocarbon group of A ^a46 preferably has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms.
The aliphatic hydrocarbon group of A ^a47 preferably has 4 to 15 carbon atoms, more preferably 5 to 12 carbon atoms, and further preferably A ^a47 has a cyclohexyl group or an adamantyl group.

A more preferable structure of the partial structure represented by * -A ^a46- X ^a44- A ^a47 (* is a bond with a carbonyl group) is the following structure.

The ^{alkanediyl group of A a41} includes a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, and a hexane-1,6-diyl group. Linear alkanediyl groups such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,2-diyl group, 1-methylbutane-1,4-diyl group, etc. Examples thereof include branched alkanediyl groups such as 2-methylbutane-1,4-diyl group.
^Examples of the substituent in the alkanediyl group of A a41 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
A ^a41 is preferably an alkanediyl group having 1 to 4 carbon atoms, more preferably an alkanediyl group having 2 to 4 carbon atoms, and further preferably an ethylene group.

^{The aliphatic hydrocarbon groups A a42} , A ^a43 and A ^{a44 in} the group (a-g1) may have a carbon-carbon unsaturated bond, but are chain and cyclic aliphatic saturated hydrocarbon groups. In addition, a group formed by combining these is preferable. The aliphatic saturated hydrocarbon group is formed by combining a linear or branched alkyl group and a monocyclic or polycyclic alicyclic hydrocarbon group, and an alkyl group and an alicyclic hydrocarbon group. Aliphatic hydrocarbon groups and the like can be mentioned. Specifically, a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a 1-methylpropane-1,3-diyl group, Examples thereof include 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.
^Examples of the substituent of the aliphatic hydrocarbon group of A a42, A ^a43 and A ^a44 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
s is preferably 0.

^{Examples of the group (ag1) in} which X a42 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group include the following groups. In the following examples, * and ** represent the bond, respectively, and ** is the bond with -O-CO-R ^a42 .

［式（ａ４−２）中、
Ｒ^f1は、水素原子又はメチル基を表す。
Ａ^f1は、炭素数１〜６のアルカンジイル基を表す。
Ｒ^f2は、フッ素原子を有する炭素数１〜１０の炭化水素基を表す。］ As the structural unit represented by the formula (a4-1), the structural unit represented by the formula (a4-2) and the formula (a4-3) is preferable.

[In equation (a4-2),
R ^f1 represents a hydrogen atom or a methyl group.
A ^f1 represents an alkanediyl group having 1 to 6 carbon atoms.
R ^f2 represents a hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom. ]

The ^{alkanediyl group of A f1} includes a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, and a pentane-1,5-diyl group. , Hexine-1,6-diyl group and other linear alkanediyl groups; 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2 Examples thereof include branched alkanediyl groups such as −diyl group, 1-methylbutane-1,4-diyl group and 2-methylbutane-1,4-diyl group.

The hydrocarbon group of R ^f2 includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group, and the aliphatic hydrocarbon group includes a chain type, a cyclic type and a group formed by a combination thereof. As the aliphatic hydrocarbon group, an alkyl group and an alicyclic hydrocarbon group are preferable.
The alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group and 2 -Ethylhexyl group is mentioned.
The alicyclic hydrocarbon group may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cycloheptyl group, a cyclodecyl group and the like. Cycloalkyl groups can be mentioned. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a 2-alkyladamantan-2-yl group, a 1- (adamantan-1-yl) alkane-1-yl group, and a norbornyl group. Examples thereof include a methylnorbornyl group and an isobornyl group.

Examples of the hydrocarbon group having a fluorine atom of R ^f2 include an alkyl group having a fluorine atom and an alicyclic hydrocarbon group having a fluorine atom.
Examples of the alkyl group having a fluorine atom include a difluoromethyl group, a trifluoromethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, a perfluoroethyl group, and 1 , 1,2,2-tetrafluoropropyl group, 1,1,2,2,3,3-hexafluoropropyl group, perfluoroethylmethyl group, 1- (trifluoromethyl) -1,2,2,2- Tetrafluoroethyl group, 1- (trifluoromethyl) -2,2,2-trifluoroethyl group, perfluoropropyl group, 1,1,2,2-tetrafluorobutyl group, 1,1,2,2,3 , 3-Hexafluorobutyl group, 1,1,2,2,3,3,4,4-octafluorobutyl group, perfluorobutyl group, 1,1-bis (trifluoro) methyl-2,2,2- Trifluoroethyl group, 2- (perfluoropropyl) ethyl group, 1,1,2,2,3,3,4,4-octafluoropentyl group, perfluoropentyl group, 1,1,2,2,3,3 , 4,4,5,5-decafluoropentyl group, 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, 2- (perfluorobutyl) ethyl group, 1 , 1,2,2,3,3,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,5,5,6,6-dodecafluoro Fluoroalkyl groups such as hexyl groups, perfluoropentylmethyl groups and perfluorohexyl groups can be mentioned.
Examples of the alicyclic hydrocarbon group having a fluorine atom include a cycloalkyl fluoride group such as a perfluorocyclohexyl group and a perfluoroadamantyl group.

^{As A f1} in the formula (a4-2), an alkanediyl group having 2 to 4 carbon atoms is preferable, and an ethylene group is more preferable.
As R ^f2 , an alkyl fluoride group having 1 to 6 carbon atoms is preferable.

［式（ａ４−３）中、
Ｒ^f11は、水素原子又はメチル基を表す。
Ａ^f11は、炭素数１〜６のアルカンジイル基を表す。
Ａ^f13は、フッ素原子を有していてもよい炭素数１〜１８の脂肪族炭化水素基を表す。
Ｘ^f12は、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ^f14は、フッ素原子を有していてもよい炭素数１〜１７の脂肪族炭化水素基を表す。
ただし、Ａ^f13及びＡ^f14の少なくとも１つは、フッ素原子を有する脂肪族炭化水素基を表す。］

[In equation (a4-3),
R ^f11 represents a hydrogen atom or a methyl group.
A ^f11 represents an alkanediyl group having 1 to 6 carbon atoms.
A ^f13 represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a fluorine atom.
X ^f12 represents a carbonyloxy group or an oxycarbonyl group.
A ^f14 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a fluorine atom.
However, ^{at least one of A f13} and A ^f14 represents an aliphatic hydrocarbon group having a fluorine atom. ]

^Examples of the alkanediyl group of A f11 include the same groups as the alkanediyl group of A ^f1 .

The aliphatic hydrocarbon group of A ^f13 includes a chain type and a cyclic type aliphatic hydrocarbon group, and a divalent aliphatic hydrocarbon group formed by combining them. This aliphatic hydrocarbon may have a carbon-carbon unsaturated bond, but is preferably a saturated aliphatic hydrocarbon group.
The ^{aliphatic hydrocarbon group which may have a fluorine atom of A f13} is preferably an aliphatic saturated hydrocarbon group which may have a fluorine atom, and more preferably a perfluoroalkanediyl group.
Examples of the divalent chain aliphatic hydrocarbon group which may have a fluorine atom include an alkanediyl group such as a methylene group, an ethylene group, a propanediyl group, a butanjiyl group and a pentandiyl group; a difluoromethylene group and a perfluoroethylene group. Examples thereof include a perfluoroalkandyl group such as a group, a perfluoropropanediyl group, a perfluorobutandyl group and a perfluoropentanediyl group.
The divalent cyclic aliphatic hydrocarbon group which may have a fluorine atom may be a group containing either a monocyclic or polycyclic group. Examples of the monocyclic aliphatic hydrocarbon group include a cyclohexanediyl group and a perfluorocyclohexanediyl group. Examples of the polycyclic divalent aliphatic hydrocarbon group include an adamantandiyl group, a norbornanediyl group, and a perfluoroadamantandiyl group.

The aliphatic hydrocarbon group of A ^f14 includes either a chain type or a cyclic type, and an aliphatic hydrocarbon group formed by combining them. This aliphatic hydrocarbon may have a carbon-carbon unsaturated bond, but is preferably a saturated aliphatic hydrocarbon group.
The ^{aliphatic hydrocarbon group which may have a fluorine atom of A f14} is preferably an aliphatic saturated hydrocarbon group which may have a fluorine atom.
Chain-type aliphatic hydrocarbon groups that may have a fluorine atom include trifluoromethyl group, difluoromethyl group, methyl group, perfluoroethyl group, 1,1,1-trifluoroethyl group, and 1,1. , 2,2-Tetrafluoroethyl group, ethyl group, perfluoropropyl group, 1,1,1,2,2-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3 , 4,4-Octafluorobutyl group, butyl group, perfluoropentyl group, 1,1,1,2,2,3,3,4,4-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group, Examples thereof include a heptyl group, a perfluoroheptyl group, an octyl group and a perfluorooctyl group.
The cyclic aliphatic hydrocarbon group which may have a fluorine atom may be either monocyclic or polycyclic. Examples of the group containing a monocyclic aliphatic hydrocarbon group include a cyclopropylmethyl group, a cyclopropyl group, a cyclobutylmethyl group, a cyclopentyl group, a cyclohexyl group, and a perfluorocyclohexyl group. Examples of the group containing a polycyclic aliphatic hydrocarbon group include an adamantyl group, an adamantyl methyl group, a norbornyl group, a norbornyl methyl group, a perfluoroadamantyl group, and a perfluoroadamantyl methyl group.

In the formula (a4-3), A ^f11 is an ethylene group is preferred.
The aliphatic hydrocarbon group of A ^f13 is preferably an aliphatic hydrocarbon group having 1 to 6 carbon atoms, and more preferably an aliphatic hydrocarbon group having 2 to 3 carbon atoms.
The aliphatic hydrocarbon group of A ^f14 is preferably an aliphatic hydrocarbon group having 3 to 12 carbon atoms, and more preferably an aliphatic hydrocarbon group having 3 to 10 carbon atoms. Among them, A ^f14 is preferably a group containing an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a cyclopropylmethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group and an adamantyl group.

Examples of the structural unit represented by the formula (a4-2) include the structural unit shown below and the structural unit in which the ^{methyl group corresponding to R f1} in the following structural unit is replaced with a hydrogen atom.

The structural unit represented by formula (a4-3), a methyl group have structural units replaced by a hydrogen atom corresponding to R ^f11 in the structural unit and the following structural units shown below.

［式（ａ４−４）中、
Ｒ^f21は、水素原子又はメチル基を表す。
Ａ^f21は、−（ＣＨ₂）_j1−、−（ＣＨ₂）_j2−Ｏ−（ＣＨ₂）_j3−又は−（ＣＨ₂）_j4−ＣＯ−Ｏ−（ＣＨ₂）_j5−を表す。
ｊ１〜ｊ５は、それぞれ独立に、１〜６のいずれかの整数を表す。
Ｒ^f22は、フッ素原子を有する炭素数１〜１０の炭化水素基を表す。］ The structural unit (a4) also includes a structural unit represented by the formula (a4-4).

[In equation (a4-4),
R ^f21 represents a hydrogen atom or a methyl group.
A ^f21 represents − (CH ₂ ) _j1 −, − (CH ₂ ) _j2 −O− (CH ₂ ) _j3 − or − (CH ₂ ) _j4 −CO−O− (CH ₂ ) _j5− .
j1 to j5 each independently represent an integer of 1 to 6.
R ^f22 represents a hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom. ]

^Examples of the hydrocarbon group having a fluorine atom of R ^{f22 include the same hydrocarbon group as R f2} in the formula (a4-2). R ^f22 is preferably an alkyl group having 1 to 10 carbon atoms having a fluorine atom or an alicyclic hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom, and an alkyl group having 1 to 10 carbon atoms having a fluorine atom is more preferable. Preferably, an alkyl group having 1 to 6 carbon atoms having a fluorine atom is more preferable.

In the formula (a4-4), as A ^f21 , − (CH ₂ ) _j1 − is preferable, an ethylene group or a methylene group is more preferable, and a methylene group is further preferable.

Examples of the structural unit represented by the formula (a4-4) include the following structural unit and the structural unit represented by the following formula in which ^{the methyl group corresponding to R f21} is replaced with a hydrogen atom. Be done.

When the resin (A) has a structural unit (a4), the content thereof is preferably 1 to 20 mol%, more preferably 2 to 15 mol%, and 3) with respect to all the structural units of the resin (A). 10 mol% is more preferable.

［式（ａ５−１）中、
Ｒ⁵¹は、水素原子又はメチル基を表す。
Ｒ⁵²は、炭素数３〜１８の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれる水素原子は炭素数１〜８の脂肪族炭化水素基又はヒドロキシ基で置換されていてもよい。但し、Ｌ⁵⁵との結合位置にある炭素原子に結合する水素原子は、炭素数１〜８の脂肪族炭化水素基で置換されない。
Ｌ⁵⁵は、単結合又は炭素数１〜１８の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。］ <Structural unit (a5)>
Examples of the non-eliminating hydrocarbon group contained in the structural unit (a5) include a linear, branched or cyclic hydrocarbon group. Among them, the structural unit (a5) preferably contains an alicyclic hydrocarbon group.
Examples of the structural unit (a5) include a structural unit represented by the formula (a5-1).

[In equation (a5-1),
R ⁵¹ represents a hydrogen atom or a methyl group.
R ⁵² represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group is substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms or a hydroxy group. You may. However, ^{the hydrogen atom bonded to the carbon atom at the bond position with L 55} is not replaced by an aliphatic hydrocarbon group having 1 to 8 carbon atoms.
L ⁵⁵ represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group. ]

The alicyclic hydrocarbon group of R ⁵² may be either a monocyclic or polycyclic group. Examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group. Examples of the polycyclic alicyclic hydrocarbon group include an adamantyl group and a norbornyl group.
The aliphatic hydrocarbon group having 1 to 8 carbon atoms includes, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. Alkyl groups such as octyl group and 2-ethylhexyl group can be mentioned.
Examples of the alicyclic hydrocarbon group having a substituent include a 3-hydroxyadamantyl group and a 3-methyladamantyl group.
R ⁵² is preferably an unsubstituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and more preferably an adamantyl group, a norbornyl group or a cyclohexyl group.

Examples of the divalent saturated hydrocarbon group of L ⁵⁵ include a divalent aliphatic saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, and a divalent aliphatic saturated hydrocarbon group is preferable. ..
Examples of the divalent aliphatic saturated hydrocarbon group include an alkanediyl group such as a methylene group, an ethylene group, a propanediyl group, a butanjiyl group and a pentandiyl group.
The divalent alicyclic saturated hydrocarbon group may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic saturated hydrocarbon group include a cycloalkanediyl group such as a cyclopentanediyl group and a cyclohexanediyl group. Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include an adamantandiyl group and a norbornanediyl group.

式（Ｌ１−１）中、
Ｘ^x1は、カルボニルオキシ基又はオキシカルボニル基を表す。
Ｌ^x1は、炭素数１〜１６の２価の脂肪族飽和炭化水素基を表す。
Ｌ^x2は、単結合又は炭素数１〜１５の２価の脂肪族飽和炭化水素基を表す。
ただし、Ｌ^x1及びＬ^x2の合計炭素数は、１６以下である。
式（Ｌ１−２）中、
Ｌ^x3は、炭素数１〜１７の２価の脂肪族飽和炭化水素基を表す。
Ｌ^x4は、単結合又は炭素数１〜１６の２価の脂肪族飽和炭化水素基を表す。
ただし、Ｌ^x3及びＬ^x4の合計炭素数は、１７以下である。
式（Ｌ１−３）中、
Ｌ^x5は、炭素数１〜１５の２価の脂肪族飽和炭化水素基を表す。
Ｌ^x6及びＬ^x7は、それぞれ独立に、単結合又は炭素数１〜１４の２価の脂肪族飽和炭化水素基を表す。
ただし、Ｌ^x5、Ｌ^x6及びＬ^x7の合計炭素数は、１５以下である。
式（Ｌ１−４）中、
Ｌ^x8及びＬ^x9は、単結合又は炭素数１〜１２の２価の脂肪族飽和炭化水素基を表す。
Ｗ^x1は、炭素数３〜１５の２価の脂環式飽和炭化水素基を表す。
ただし、Ｌ^x8、Ｌ^x9及びＷ^x1の合計炭素数は、１５以下である。 Examples of the group in which the methylene group contained in the saturated hydrocarbon group is replaced with an oxygen atom or a carbonyl group include groups represented by the formulas (L1-1) to (L1-4). In the following formula, * represents a bond with an oxygen atom.

In formula (L1-1),
X ^x1 represents a carbonyloxy group or an oxycarbonyl group.
L ^x1 represents a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
L ^x2 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
However, the total number of carbon atoms of ^{L x1} and L ^{x2 is 16 or less.}
In formula (L1-2),
L ^x3 represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms.
L ^x4 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
However, the total number of carbon atoms of ^{L x3} and L ^{x4 is 17 or less.}
In formula (L1-3),
L ^x5 represents a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^x6 and L ^x7 each independently represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms.
However, the total number of carbon atoms of ^{L x5} , L ^x6 and L ^{x7 is 15 or less.}
In formula (L1-4),
L ^x8 and L ^x9 represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms.
W ^{x 1} represents a divalent alicyclic saturated hydrocarbon group having 3 to 15 carbon atoms.
However, the total number of carbon atoms of ^{L x8} , L ^x9 and W ^{x1 is 15 or less.}

L ^x1 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a methylene group or an ethylene group.
L ^x2 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a single bond.
L ^x3 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x4 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x5 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a methylene group or an ethylene group.
L ^x6 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a methylene group or an ethylene group.
L ^x7 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x8 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a single bond or a methylene group.
L ^x9 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a single bond or a methylene group.
W ^{x 1} is preferably a divalent alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms, and more preferably a cyclohexanediyl group or an adamantandiyl group.

Examples of the group represented by the formula (L1-1) include the divalent groups shown below.

Examples of the group represented by the formula (L1-2) include the following divalent groups.

Examples of the group represented by the formula (L1-3) include the divalent groups shown below.

Examples of the group represented by the formula (L1-4) include the divalent groups shown below.

L ⁵⁵ is preferably a single bond or a group represented by the formula (L1-1).

Examples of the structural unit (a5-1) include the structural unit shown below and the structural unit in which the ^{methyl group corresponding to R 51} in the following structural unit is replaced with a hydrogen atom.

When the resin (A) has a structural unit (a5), the content thereof is preferably 1 to 30 mol%, more preferably 2 to 20 mol%, and 3) with respect to all the structural units of the resin (A). ~ 15 mol% is more preferred.

The resin (A) is preferably a resin composed of a structural unit (a1) and a structural unit (s), that is, a copolymer of a monomer (a1) and a monomer (s).
The structural unit (s) is preferably at least one of the structural unit (a2) and the structural unit (a3). The structural unit (a2) is preferably a structural unit represented by the formula (a2-1).
The structural unit (a3) is preferably selected from the structural unit represented by the formula (a3-1), the structural unit represented by the formula (a3-2), and the structural unit represented by the formula (a3-4). At least one kind.

Each structural unit constituting the resin (A) may be used alone or in combination of two or more, and is produced by a known polymerization method (for example, a radical polymerization method) using a monomer for inducing these structural units. can do. The content of each structural unit of the resin (A) can be adjusted by adjusting the amount of the monomer used for the polymerization.
The weight average molecular weight of the resin (A) is preferably 2,000 or more (more preferably 2,500 or more, still more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less, still more preferable. Is 15,000 or less).

<Resin other than resin (A)>
The resist composition of the present invention may contain a resin other than the resin (A). Examples of such a resin include a resin composed of only the structural unit (s), a resin containing the structural unit (a4) (however, the resin does not include the structural unit (a1); hereinafter may be referred to as “resin (X)”) and the like. Can be mentioned. Of these, a resin containing the structural unit (a4) is preferable.
In the resin (X), the content of the structural unit (a4) is preferably 40 mol% or more, more preferably 45 mol% or more, still more preferably 50 mol% or more, based on all the structural units of the resin (X). ..
Examples of the structural unit that the resin (X) may further include include a structural unit (a2), a structural unit (a3), and a structural unit derived from other known monomers.
The weight average molecular weight of the resin (X) is preferably 6,000 or more (more preferably 7,000 or more) and 80,000 or less (more preferably 60,000 or less). The means for measuring the weight average molecular weight of the resin (X) is the same as that of the resin (A).
When the resist composition contains the resin (X), the content thereof is preferably 1 to 60 parts by mass, more preferably 2 to 50 parts by mass, and further, with respect to 100 parts by mass of the resin (A). It is preferably 2 to 40 parts by mass, and particularly preferably 2 to 30 parts by mass.

The total content of the resin (A) and the resin other than the resin (A) is preferably 80% by mass or more and 99% by mass or less, and preferably 90% by mass or more and 99% by mass or less with respect to the solid content of the resist composition. ..
The solid content of the resist composition and the content of the resin relative to the solid content can be measured by a known analytical means such as liquid chromatography or gas chromatography.

<Solvent (E)>
The content of the solvent (E) is usually 90% by mass or more, preferably 92% by mass or more, more preferably 94% by mass or more, and usually 99.9% by mass or less, preferably 99% by mass or less in the resist composition. Is. The content of the solvent (E) can be measured by a known analytical means such as liquid chromatography or gas chromatography.

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 ethyl pyruvate. Esters; ketones such as acetone, methylisobutylketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; and the like. The solvent (E) may contain one type alone or two or more types.

<Quencher (C)>
Examples of the quencher (C) include a basic nitrogen-containing organic compound or a salt that generates an acid having a weaker acidity than the acid generated from the salt (I) and the acid generator (B).

<Basic nitrogen-containing organic compounds>
Examples of the basic nitrogen-containing organic compound include amine and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines.

Specifically, 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, trypentylamine, trihexylamine, Triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine , Ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, Triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino- 3,3'-diethyldiphenylmethane, piperazine, morpholin, piperidine and hindered amine compounds having a piperidine skeleton described in JP-A-11-52575, imidazole, 4-methylimidazole, pyridine, 4-methylpyridine, 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'-dipyridyl Amine, 2,2'-dipicolylamine, bipyridine and the like can be mentioned, preferably diisopropylaniline, and particularly preferably 2,6-diisopropylaniline.

Ammonium salts include 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.

<Salt that generates acid with weak acidity>
The acidity of a salt that produces an acid that is weaker than the acid generated from the salt (I) and the acid generator (B) is indicated by the acid dissociation constant (pKa). A salt that generates an acid having a weaker acidity than the acid generated from the salt (I) and the acid generator (B) usually has an acid dissociation constant of -3 <pKa. A salt of -1 <pKa <7 is preferable, and a salt of 0 <pKa <5 is more preferable. Examples of the salt that generates an acid having a weaker acidity than the acid generated from the acid generator (B) include a salt represented by the following formula, a weak acid intramolecular salt represented by the formula (D), and JP-A-2012-. Examples thereof include the salts described in JP-A-229206, JP-A-2012-6908, JP-A-2012-72109, JP-A-2011-39502 and JP-A-2011-191745. It is preferably a weak acid intramolecular salt represented by the formula (D) (hereinafter, may be referred to as “weak acid intramolecular salt (D)”).

［式（Ｄ）中、
Ｒ^D1及びＲ^D2は、それぞれ独立に、炭素数１〜１２の炭化水素基、炭素数１〜６のアルコキシ基、炭素数２〜７のアシル基、炭素数２〜７のアシルオキシ基、炭素数２〜７のアルコキシカルボニル基、ニトロ基又はハロゲン原子を表す。
ｍ’及びｎ’は、それぞれ独立に、０〜４のいずれかの整数を表し、ｍ’が２以上の場合、複数のＲ^D1は同一又は相異なり、ｎ’が２以上の場合、複数のＲ^D2は同一又は相異なる。］

[In formula (D),
R ^D1 and R ^D2 independently have a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 7 carbon atoms, an acyloxy group having 2 to 7 carbon atoms, and a carbon number of carbon atoms. Represents 2 to 7 alkoxycarbonyl groups, nitro groups or halogen atoms.
m'and n'independently represent an integer of 0 to 4, and when m'is 2 or more, a plurality of ^RD1s are the same or different, and when n'is 2 or more, a plurality of RD1s are the same or different. R ^D2 is the same or different. ]

In the weak acid intramolecular salt (D), ^{the hydrocarbon groups of R D1} and R ^D2 are aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and groups formed by combining them. And so on.
Examples of the aliphatic hydrocarbon group include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group and nonyl group.
The alicyclic hydrocarbon group may be either a monocyclic or polycyclic group, and may be saturated or unsaturated. Examples thereof include cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclononyl group and cyclododecyl group, norbonyl group and adamantyl group.
Examples of the aromatic hydrocarbon group include phenyl group, 1-naphthyl group, 2-naphthyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group and 4-propylphenyl group. , 4-isopropylphenyl group, 4-butylphenyl group, 4-t-butylphenyl group, 4-hexylphenyl group, 4-cyclohexylphenyl group, anthryl group, p-adamantylphenyl group, trill group, xsilyl group, cumenyl group , Mesityl group, biphenyl group, phenanthryl group, aryl group such as 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl and the like.
Examples of the group formed by combining these groups include an alkyl-cycloalkyl group, a cycloalkyl-alkyl group, and an aralkyl group (for example, a phenylmethyl group, a 1-phenylethyl group, a 2-phenylethyl group, and a 1-phenyl-1 group. -Propyl group, 1-Phenyl-2-propyl group, 2-Phenyl-2-propyl group, 3-Phenyl-1-propyl group, 4-Phenyl-1-butyl group, 5-Phenyl-1-pentyl group, 6 −Phenyl-1-hexyl group, etc.) and the like.

Examples of the alkoxy group include a methoxy group and an ethoxy group.
Examples of the acyl group include an acetyl group, a propanoyl group, a benzoyl group, a cyclohexanecarbonyl group and the like.
Examples of the acyloxy group include a group in which an oxy group (−O−) is bonded to the above acyl group.
Examples of the alkoxycarbonyl group include a group in which a carbonyl group (−CO−) is bonded to the above alkoxy group.
Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom.

In the formula (D), ^RD1 and ^RD2 independently have an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and 2 to 2 carbon atoms. An acyl group of 4 and an acyloxy group having 2 to 4 carbon atoms, an alkoxycarbonyl group having 2 to 4 carbon atoms, a nitro group or a halogen atom are preferable.
For m'and n', any integer of 0 to 2 is preferable, and 0 is more preferable. When m'is 2 or more, a plurality of R ^D1s are the same or different, and when n'is 2 or more, a plurality of R ^D2s are the same or different.

Examples of the weak acid intramolecular salt (D) include the following compounds.

The content of the quencher (C) is preferably 0.01 to 5% by mass, more preferably 0.01 to 4% by mass, and particularly preferably 0.01 to 3% by mass, based on the solid content of the resist composition. It is mass%.

<Other ingredients>
If necessary, the resist composition may contain components other than the above-mentioned components (hereinafter, may be referred to as "other components (F)"). As the other component (F), additives known in the field of resist, for example, sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes and the like can be used.

<Preparation of resist composition>
The resist composition includes an acid generator containing a resin (A) and a salt (I), and if necessary, a resin other than the resin (A), an acid generator (B), a solvent (E), and a quencher ( It can be prepared by mixing C) and the other component (F). The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can be selected from 10 to 40 ° C., depending on the type of resin or the like and the solubility of the resin or the like in the solvent (E). The 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 or the like can be used.
After mixing each component, it is preferable to filter using a filter having a pore size of about 0.003 to 0.2 μm.

[Manufacturing method of resist pattern]
The method for producing a resist pattern of the present invention is
(1) A step of applying the resist composition of the present invention on a substrate,
(2) A step of drying the applied composition to form a composition layer,
(3) Step of exposing the composition layer,
It includes (4) a step of heating the composition layer after exposure and (5) a step of developing the composition layer after heating.

The resist composition can be applied onto the substrate by a commonly used device such as a spin coater. Examples of the substrate include an inorganic substrate such as a silicon wafer. Before applying the resist composition, the substrate may be washed, or an antireflection film or the like may be formed on the substrate.

By drying the composition after coating, the solvent is removed and a composition layer is formed. Drying is performed, for example, by evaporating the solvent using a heating device such as a hot plate (so-called prebaking), or by using a decompression device. The heating temperature is preferably 50 to 200 ° C., and the heating time is preferably 10 to 180 seconds. The pressure at the time of vacuum drying is preferably about 1~1.0 × 10 ⁵ Pa.

The obtained composition layer is usually exposed to an exposure machine. The exposure machine may be an immersion exposure machine. Exposure light sources include those that emit ultraviolet laser light such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), and F ₂ excimer laser (wavelength 157 nm), and solid-state laser light sources (YAG or semiconductor laser). Etc.), wavelength-converted laser light from far-ultraviolet region or vacuum ultraviolet region to emit harmonic laser light, electron beam, super-ultraviolet light (EUV) irradiation, etc. Can be done. In addition, in this specification, irradiating these radiations may be generically referred to as "exposure". At the time of exposure, the exposure is usually performed through a mask corresponding to the required pattern. When the exposure light source is an electron beam, the exposure may be performed by drawing directly without using a mask.

The exposed composition layer is heat treated (so-called post-exposure bake) to promote the deprotection reaction at the acid-labile group. The heating temperature is usually about 50 to 200 ° C, preferably about 70 to 150 ° C.

The composition layer after heating is usually developed using a developing solution using a developing device. Examples of the developing method include a dip method, a paddle method, a spray method, and a dynamic dispense method. The developing temperature is preferably 5 to 60 ° C., and the developing time is preferably 5 to 300 seconds. A positive resist pattern or a negative resist pattern can be produced by selecting the type of developer as follows.

When producing a positive resist pattern from a resist composition, an alkaline developer is used as the developer. The alkaline developer may be any alkaline aqueous solution used in this field. Examples thereof include an aqueous solution of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as choline). The alkaline developer may contain a surfactant.
After development, it is preferable to wash the resist pattern with ultrapure water and then remove the substrate and water remaining on the pattern.

When a negative resist pattern is produced from a resist composition, a developer containing an organic solvent (hereinafter, may be referred to as "organic developer") is used as the developer.
Examples of the organic solvent contained in the organic developing solution include a ketone solvent such as 2-hexanone and 2-heptanone; a glycol ether ester solvent such as propylene glycol monomethyl ether acetate; an ester solvent such as butyl acetate; and a glycol such as propylene glycol monomethyl ether. Examples thereof include ether solvents; amide solvents such as N and N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole.
The content of the organic solvent in the organic developer is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and further preferably substantially only the organic solvent.
As the organic developer, a developer containing butyl acetate and / or 2-heptanone is preferable. The total content of butyl acetate and 2-heptanone in the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and substantially butyl acetate and / or 2 -It is even more preferable that it is only heptanone.
The organic developer may contain a surfactant. Further, the organic developer may contain a small amount of water.
At the time of development, the development may be stopped by substituting with a solvent of a type different from that of the organic developer.

It is preferable to wash the developed resist pattern with a rinse solution. The rinsing liquid is not particularly limited as long as it does not dissolve the resist pattern, and a solution containing a general organic solvent can be used, and an alcohol solvent or an ester solvent is preferable.
After cleaning, it is preferable to remove the rinse liquid remaining on the substrate and the pattern.

<Use>
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) exposure, or a resist composition for EUV exposure, particularly ArF. It is suitable as a resist composition for excimer laser exposure and is useful for fine processing of semiconductors.

An example will be given and a more specific description will be given. In the examples, "%" and "part" representing the content or the amount used are based on mass unless otherwise specified.
The weight average molecular weight is a value obtained by gel permeation chromatography under the following conditions.
Equipment: HLC-8120GPC type (manufactured by Tosoh Corporation)
Column: TSKgel Multipore H _XL -M x 3 + guardcolumn (manufactured by Tosoh)
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)

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

式（Ｉ−Ｘ１−ａ）で表される化合物２３．５０部、式（Ｉ−Ｘ１−ｂ）で表される化合物１７．４４部、酢酸５２．３３部及び無水酢酸２６．１７部を添加し、２３℃で３０分間攪拌した。得られた混合溶液を５℃まで冷却した後、硫酸１７．４４部を１５分かけて滴下し、５℃で３時間攪拌した後、２３℃まで昇温し、さらに、２３℃で１２時間攪拌した。得られた反応マスに、ｔｅｒｔ−ブチルメチルエーテル５５部及びイオン交換水５５部を加えて２３℃で３０分間攪拌した後、ろ過し、ろ液を分液して有機層を回収した。回収された有機層に、臭化ナトリウム８．７２部及びイオン交換水４３．６１部を加えて２３℃で３０分間攪拌した後、ろ過することにより、式（Ｉ−Ｘ１−ｃ）で表される塩８．８１部を得た。

式（Ｉ−Ｘ１−ｃ）で表される塩８．８１部及びクロロホルム４４．３０部を添加し、２３℃で３０分間攪拌した。得られた混合溶液に、ジメチル硫酸３．０８部を添加し、さらに、メタノール８８．６０部を添加した後、２３℃で２４時間攪拌した。得られた反応マスを濃縮した後、得られた濃縮残に、ｔｅｒｔ−ブチルメチルエーテル４４．５部を加えて２３℃で３０分間攪拌し、上澄み液を除去し、濃縮することにより、式（Ｉ−Ｘ１−ｄ）で表される塩８．９９部を得た。

式（Ｉ−Ｘ１−ｄ）で表される塩３．２７部、式（Ｉ−Ｘ１−ｅ）で表される化合物０．８０部及びクロロホルム２６．１６部を添加し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ−Ｘ１−ｆ）で表される化合物０．０２部を添加した後、６０℃で５時間還流攪拌した。得られた反応マスに、モノクロロベンゼン２６．１６部を添加した後、８０℃で４時間かけて還流攪拌しながら、クロロホルムを留去した。更に、１００℃で４時間還流攪拌した後、濃縮した。得られた濃縮残に、ｔｅｒｔ−ブチルメチルエーテル１０部を加えて２３℃で３０分間攪拌し、上澄み液を除去し、濃縮することにより、式（Ｉ−Ｘ１）で表される塩１．２８部を得た。 Example 1: Synthesis of salt represented by the formula (IX1)

23.50 parts of the compound represented by the formula (I-X1-a), 17.44 parts of the compound represented by the formula (I-X1-b), 52.33 parts of acetic acid and 26.17 parts of acetic anhydride were added. Then, the mixture was stirred at 23 ° C. for 30 minutes. After cooling the obtained mixed solution to 5 ° C., 17.44 parts of sulfuric acid was added dropwise over 15 minutes, the mixture was stirred at 5 ° C. for 3 hours, the temperature was raised to 23 ° C., and the mixture was further stirred at 23 ° C. for 12 hours. bottom. 55 parts of tert-butyl methyl ether and 55 parts of ion-exchanged water were added to the obtained reaction mass, and the mixture was stirred at 23 ° C. for 30 minutes, filtered, and the filtrate was separated to recover the organic layer. To the recovered organic layer, 8.72 parts of sodium bromide and 43.61 parts of ion-exchanged water were added, stirred at 23 ° C. for 30 minutes, and then filtered to be represented by the formula (I-X1-c). 8.81 parts of salt was obtained.

8.81 parts of the salt represented by the formula (I-X1-c) and 44.30 parts of chloroform were added, and the mixture was stirred at 23 ° C. for 30 minutes. To the obtained mixed solution, 3.08 parts of dimethyl sulfate was added, and 88.60 parts of methanol was further added, and then the mixture was stirred at 23 ° C. for 24 hours. After concentrating the obtained reaction mass, 44.5 parts of tert-butyl methyl ether was added to the obtained concentrated residue, and the mixture was stirred at 23 ° C. for 30 minutes to remove the supernatant and concentrated. 8.99 parts of salt represented by I-X1-d) was obtained.

3.27 parts of the salt represented by the formula (I-X1-d), 0.80 part of the compound represented by the formula (I-X1-e) and 26.16 parts of chloroform were added, and the mixture was added at 23 ° C. for 30 minutes. Stirred. 0.02 part of the compound represented by the formula (I-X1-f) was added to the obtained mixed solution, and the mixture was stirred under reflux at 60 ° C. for 5 hours. After adding 26.16 parts of monochlorobenzene to the obtained reaction mass, chloroform was distilled off while refluxing and stirring at 80 ° C. for 4 hours. Further, the mixture was refluxed and stirred at 100 ° C. for 4 hours and then concentrated. To the obtained concentrated residue, 10 parts of tert-butyl methyl ether was added, and the mixture was stirred at 23 ° C. for 30 minutes to remove the supernatant and concentrated to obtain 1.28 salt represented by the formula (IX1). I got a part.

MASS (ESI (+) Spectrum): M ⁺ 199.1
MASS (ESI (-) Spectrum): M ^- 111.0

式（Ｉ−Ｘ１−ｃ）で表される塩３．０３部、式（Ｉ−Ｘ１−ｅ）で表される化合物０．８０部及びクロロホルム２６．１６部を添加し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ−Ｘ１−ｆ）で表される化合物０．０２部を添加した後、６０℃で５時間還流攪拌した後、濃縮した。得られた濃縮残に、ｔｅｒｔ−ブチルメチルエーテル１０部を加えて２３℃で３０分間攪拌し、上澄み液を除去し、濃縮することにより、式（Ｉ−Ｘ２）で表される塩１．４４部を得た。 Example 2: Synthesis of salt represented by the formula (IX2)

3.03 parts of the salt represented by the formula (I-X1-c), 0.80 part of the compound represented by the formula (I-X1-e) and 26.16 parts of chloroform were added, and the mixture was added at 23 ° C. for 30 minutes. Stirred. 0.02 part of the compound represented by the formula (I-X1-f) was added to the obtained mixed solution, and the mixture was stirred under reflux at 60 ° C. for 5 hours and then concentrated. To the obtained concentrated residue, 10 parts of tert-butyl methyl ether was added, and the mixture was stirred at 23 ° C. for 30 minutes to remove the supernatant and concentrated to obtain 1.44 salt represented by the formula (IX2). I got a part.

MASS (ESI (+) Spectrum): M ⁺ 199.1
MASS (ESI (-) Spectrum): M ^- 78.9

式（Ｉ−Ｘ２）で表される塩１．１７部及びクロロホルム１０部を添加し、２３℃で３０分間攪拌した。得られた混合溶液に、フッ化銀０．５３部を添加した後、２３℃で１２０時間攪拌した後、ろ過した。回収されたろ液を濃縮した後、ｔｅｒｔ−ブチルメチルエーテル５部を加えて２３℃で３０分間攪拌し、上澄み液を除去し、濃縮することにより、式（Ｉ−Ｘ３）で表される塩０．３４部を得た。 Example 3: Synthesis of salt represented by formula (IX3)

1.17 parts of the salt represented by the formula (IX2) and 10 parts of chloroform were added, and the mixture was stirred at 23 ° C. for 30 minutes. After adding 0.53 part of silver fluoride to the obtained mixed solution, the mixture was stirred at 23 ° C. for 120 hours and then filtered. After concentrating the recovered filtrate, 5 parts of tert-butyl methyl ether is added, and the mixture is stirred at 23 ° C. for 30 minutes to remove the supernatant and concentrated to obtain salt 0 represented by the formula (IX3). .34 copies were obtained.

MASS (ESI (+) Spectrum): M ⁺ 199.1
MASS (ESI (-) Spectrum): M ^- 19.0

式（Ｉ−Ｘ１）で表される塩３．２５部及びクロロホルム６０部を仕込んだ後、式（Ｉ−２−ａ）で表される塩８．９２部及びイオン交換水３０部を仕込み、２３℃で１２時間攪拌した。得られた反応液を分液して有機層を取り出した。回収された有機層にイオン交換水３０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を２回繰り返した。得られた残渣を濃縮した後、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌した後、上澄み液を除去した。得られた残渣を濃縮することにより、式（Ｉ−２）で表される塩４．４８部を得た。 Example 4: Synthesis of salt represented by formula (I-2)

After charging 3.25 parts of the salt represented by the formula (IX1) and 60 parts of chloroform, 8.92 parts of the salt represented by the formula (I-2-a) and 30 parts of ion-exchanged water were charged. The mixture was stirred at 23 ° C. for 12 hours. The obtained reaction solution was separated and the organic layer was taken out. After adding 30 parts of ion-exchanged water to the recovered organic layer and stirring at 23 ° C. for 30 minutes, the liquid was separated and the organic layer was taken out. This washing operation was repeated twice. After concentrating the obtained residue, 30 parts of tert-butyl methyl ether was added to the obtained residue and stirred, and then the supernatant was removed. By concentrating the obtained residue, 4.48 parts of a salt represented by the formula (I-2) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 199.1
MASS (ESI (-) Spectrum): M ^- 323.0

式（Ｉ−Ｘ１−ｄ）で表される塩４．４９部及びクロロホルム６０部を仕込んだ後、式（Ｉ−２−ａ）で表される塩８．９２部及びイオン交換水３０部を仕込み、２３℃で１２時間攪拌した。得られた反応液を分液して有機層を取り出した。回収された有機層にイオン交換水３０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を２回繰り返した。得られた残渣を濃縮した後、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌した後、上澄み液を除去した。得られた残渣を濃縮することにより、式（Ｉ−２６−ａ）で表される塩５．９８部を得た。 Example 5: Synthesis of salt represented by formula (I-26)

After charging 4.49 parts of the salt represented by the formula (I-X1-d) and 60 parts of chloroform, 8.92 parts of the salt represented by the formula (I-2-a) and 30 parts of ion-exchanged water were added. The mixture was charged and stirred at 23 ° C. for 12 hours. The obtained reaction solution was separated and the organic layer was taken out. After adding 30 parts of ion-exchanged water to the recovered organic layer and stirring at 23 ° C. for 30 minutes, the liquid was separated and the organic layer was taken out. This washing operation was repeated twice. After concentrating the obtained residue, 30 parts of tert-butyl methyl ether was added to the obtained residue and stirred, and then the supernatant was removed. By concentrating the obtained residue, 5.98 parts of a salt represented by the formula (I-26-a) was obtained.

式（Ｉ−２６−ａ）で表される塩４．２５部、式（Ｉ−２６−ｂ）で表される化合物０．８０部及びクロロホルム４０部を添加し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ−２６−ｃ）で表される化合物０．０２部を添加し、さらに、６０℃で７２時間還流攪拌した。得られた反応マスを２３℃まで冷却後、５％シュウ酸水溶液１３．３３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。回収された有機層にイオン交換水１３．３３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５回繰り返した。得られた有機層をろ過した後、回収されたろ液を濃縮し、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌した後、上澄み液を除去した。得られた残渣を濃縮することにより、式（Ｉ−２６）で表される塩２．６８部を得た。

4.25 parts of the salt represented by the formula (I-26-a), 0.80 part of the compound represented by the formula (I-26-b) and 40 parts of chloroform were added, and the mixture was stirred at 23 ° C. for 30 minutes. .. To the obtained mixed solution, 0.02 part of the compound represented by the formula (I-26-c) was added, and the mixture was further reflux-stirred at 60 ° C. for 72 hours. The obtained reaction mass was cooled to 23 ° C., 13.33 parts of a 5% aqueous oxalic acid solution was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated and the organic layer was taken out. 13.33 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to remove the organic layer. This operation was repeated 5 times. After filtering the obtained organic layer, the recovered filtrate was concentrated, 30 parts of tert-butyl methyl ether was added to the obtained residue, and the mixture was stirred, and then the supernatant was removed. By concentrating the obtained residue, 2.68 parts of a salt represented by the formula (I-26) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 215.0
MASS (ESI (-) Spectrum): M ^- 323.0

式（Ｉ−Ｘ１）で表される塩３．２５部及びクロロホルム６０部を仕込んだ後、式（Ｉ−６−ａ）で表される塩１１．９４部及びイオン交換水３０部を仕込み、２３℃で１２時間攪拌した。得られた反応液を分液して有機層を取り出した。回収された有機層にイオン交換水３０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を２回繰り返した。得られた残渣を濃縮した後、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌した後、上澄み液を除去した。得られた残渣を濃縮することにより、式（Ｉ−６）で表される塩４．７２部を得た。 Example 5: Synthesis of salt represented by formula (I-6)

After charging 3.25 parts of the salt represented by the formula (IX1) and 60 parts of chloroform, 11.94 parts of the salt represented by the formula (I-6-a) and 30 parts of ion-exchanged water were charged. The mixture was stirred at 23 ° C. for 12 hours. The obtained reaction solution was separated and the organic layer was taken out. After adding 30 parts of ion-exchanged water to the recovered organic layer and stirring at 23 ° C. for 30 minutes, the liquid was separated and the organic layer was taken out. This washing operation was repeated twice. After concentrating the obtained residue, 30 parts of tert-butyl methyl ether was added to the obtained residue and stirred, and then the supernatant was removed. By concentrating the obtained residue, 4.72 parts of a salt represented by the formula (I-6) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 199.1
MASS (ESI (-) Spectrum): M ^- 467.1

式（Ｉ−Ｘ１−ｄ）で表される塩６．７２部及びクロロホルム３０部を仕込んだ後、式（Ｉ−６−ａ）で表される塩５．９６及びイオン交換水１５部を仕込み、２３℃で１２時間攪拌した。得られた反応液を分液して有機層を取り出した。回収された有機層にイオン交換水１５部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を５回繰り返した。得られた残渣を濃縮した後、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル１５部を加えて攪拌した後、上澄み液を除去した。得られた残渣を濃縮することにより、式（Ｉ−３０−ａ）で表される塩６．８４部を得た。 Example 6: Synthesis of salt represented by formula (I-30)

After charging 6.72 parts of the salt represented by the formula (I-X1-d) and 30 parts of chloroform, 5.96 parts of the salt represented by the formula (I-6-a) and 15 parts of ion-exchanged water were charged. , Stirred at 23 ° C. for 12 hours. The obtained reaction solution was separated and the organic layer was taken out. After adding 15 parts of ion-exchanged water to the recovered organic layer and stirring at 23 ° C. for 30 minutes, the liquid was separated and the organic layer was taken out. This washing operation was repeated 5 times. After concentrating the obtained residue, 15 parts of tert-butyl methyl ether was added to the obtained residue and stirred, and then the supernatant was removed. By concentrating the obtained residue, 6.84 parts of a salt represented by the formula (I-30-a) was obtained.

式（Ｉ−３０−ａ）で表される塩５．２１部、式（Ｉ−２６−ｂ）で表される化合物０．８０部及びクロロホルム４０部を添加し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ−２６−ｃ）で表される化合物０．０２部を添加し、さらに、６０℃で７２時間還流攪拌した。得られた反応マスを２３℃まで冷却後、５％シュウ酸水溶液１３．３３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。回収された有機層にイオン交換水１３．３３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５回繰り返した。得られた有機層をろ過した後、回収されたろ液を濃縮し、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌した後、上澄み液を除去した。得られた残渣を濃縮することにより、式（Ｉ−３０）で表される塩２．５１部を得た。

5.21 parts of the salt represented by the formula (I-30-a), 0.80 parts of the compound represented by the formula (I-26-b) and 40 parts of chloroform were added, and the mixture was stirred at 23 ° C. for 30 minutes. .. To the obtained mixed solution, 0.02 part of the compound represented by the formula (I-26-c) was added, and the mixture was further reflux-stirred at 60 ° C. for 72 hours. The obtained reaction mass was cooled to 23 ° C., 13.33 parts of a 5% aqueous oxalic acid solution was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated and the organic layer was taken out. 13.33 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to remove the organic layer. This operation was repeated 5 times. After filtering the obtained organic layer, the recovered filtrate was concentrated, 30 parts of tert-butyl methyl ether was added to the obtained residue, and the mixture was stirred, and then the supernatant was removed. By concentrating the obtained residue, 2.51 parts of a salt represented by the formula (I-30) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 215.0
MASS (ESI (-) Spectrum): M ^- 467.1

式（Ｉ−Ｘ４−ｂ）で表される化合物５．００部、ヨウ素１．９８部及び硫酸２０．００部を添加し、２３℃で３０分間攪拌した。得られた混合溶液を５℃まで冷却した後、式（Ｉ−Ｘ４−ａ）で表される化合物８．４３部を１５分かけて添加し、５℃で３時間攪拌した後、２３℃で１時間、さらに、５０℃で１０時間攪拌した。得られた反応マスに、ｔｅｒｔ−ブチルメチルエーテル３０部及びイオン交換水４０部を加えて２３℃で３０分間攪拌した後、ろ過し、ろ液を回収した。回収されたろ液に、臭化ナトリウム２．５０部及びイオン交換水１２．５０部を加えて２３℃で３０分間攪拌した後、ろ過することにより、式（Ｉ−Ｘ４−ｃ）で表される塩２．４８部を得た。

式（Ｉ−Ｘ４−ｃ）で表される塩２．００部、メタノール２０部及び臭化ナトリウム０．５０部を添加し、２３℃で１時間攪拌した。得られた混合溶液に、ジメチル硫酸０．７４部を添加し、２３℃で２４時間攪拌した。得られた反応マスを濃縮した後、得られた濃縮残に、ｔｅｒｔ−ブチルメチルエーテル２０部を加えて２３℃で３０分間攪拌し、上澄み液を除去し、濃縮することにより、式（Ｉ−Ｘ４−ｄ）で表される塩１．４５部を得た。

式（Ｉ−Ｘ４−ｄ）で表される塩１．４５部、式（Ｉ−Ｘ４−ｅ）で表される化合物０．３４部及びクロロホルム２９部を添加し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ−Ｘ４−ｆ）で表される化合物０．０１部を添加した後、６０℃で５時間還流攪拌した後、濃縮した。得られた濃縮残に、ｔｅｒｔ−ブチルメチルエーテル１０部を加えて２３℃で３０分間攪拌し、上澄み液を除去し、濃縮することにより、式（Ｉ−Ｘ４）で表される塩０．９２部を得た。 Example 7: Synthesis of salt represented by the formula (IX4)

5.00 parts of the compound represented by the formula (I-X4-b), 1.98 parts of iodine and 20.00 parts of sulfuric acid were added, and the mixture was stirred at 23 ° C. for 30 minutes. After cooling the obtained mixed solution to 5 ° C., 8.43 parts of the compound represented by the formula (I-X4-a) was added over 15 minutes, and the mixture was stirred at 5 ° C. for 3 hours and then at 23 ° C. The mixture was stirred for 1 hour and further at 50 ° C. for 10 hours. To the obtained reaction mass, 30 parts of tert-butyl methyl ether and 40 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes, filtered, and the filtrate was recovered. To the recovered filtrate, 2.50 parts of sodium bromide and 12.50 parts of ion-exchanged water are added, and the mixture is stirred at 23 ° C. for 30 minutes and then filtered to be represented by the formula (I-X4-c). 2.48 parts of salt was obtained.

2.00 parts of the salt represented by the formula (I-X4-c), 20 parts of methanol and 0.50 parts of sodium bromide were added, and the mixture was stirred at 23 ° C. for 1 hour. 0.74 parts of dimethyl sulfate was added to the obtained mixed solution, and the mixture was stirred at 23 ° C. for 24 hours. After concentrating the obtained reaction mass, 20 parts of tert-butyl methyl ether was added to the obtained concentrated residue, and the mixture was stirred at 23 ° C. for 30 minutes to remove the supernatant and concentrated to obtain the formula (I-). 1.45 parts of salt represented by X4-d) was obtained.

1.45 parts of the salt represented by the formula (I-X4-d), 0.34 parts of the compound represented by the formula (I-X4-e) and 29 parts of chloroform were added, and the mixture was stirred at 23 ° C. for 30 minutes. .. To the obtained mixed solution, 0.01 part of the compound represented by the formula (I-X4-f) was added, and the mixture was reflux-stirred at 60 ° C. for 5 hours and then concentrated. To the obtained concentrated residue, 10 parts of tert-butyl methyl ether was added, and the mixture was stirred at 23 ° C. for 30 minutes to remove the supernatant and concentrated to obtain a salt of 0.92 represented by the formula (IX4). I got a part.

MASS (ESI (+) Spectrum): M ⁺ 206.1
MASS (ESI (-) Spectrum): M ^- 111.0

式（Ｉ−Ｘ４）で表される塩０．６６部及びクロロホルム２０部を仕込んだ後、式（Ｉ−６−ａ）で表される塩２．３９部及びイオン交換水６部を仕込み、２３℃で１２時間攪拌した。得られた反応液を分液して有機層を取り出した。回収された有機層にイオン交換水１０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を２回繰り返した。得られた残渣を濃縮した後、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル１０部を加えて攪拌した後、上澄み液を除去した。得られた残渣を濃縮することにより、式（Ｉ−５４）で表される塩０．９１部を得た。 Example 8: Synthesis of salt represented by formula (I-54)

After charging 0.66 parts of salt represented by the formula (IX4) and 20 parts of chloroform, 2.39 parts of salt represented by the formula (I-6-a) and 6 parts of ion-exchanged water were charged. The mixture was stirred at 23 ° C. for 12 hours. The obtained reaction solution was separated and the organic layer was taken out. After adding 10 parts of ion-exchanged water to the recovered organic layer and stirring at 23 ° C. for 30 minutes, the liquid was separated and the organic layer was taken out. This washing operation was repeated twice. After concentrating the obtained residue, 10 parts of tert-butyl methyl ether was added to the obtained residue and stirred, and then the supernatant was removed. By concentrating the obtained residue, 0.91 part of a salt represented by the formula (I-54) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 206.1
MASS (ESI (-) Spectrum): M ^- 467.1

式（Ｉ−Ｘ５−ｂ）で表される化合物５．００部、ヨウ素１．９８部及び硫酸２０．００部を添加し、２３℃で３０分間攪拌した。得られた混合溶液を５℃まで冷却した後、式（Ｉ−Ｘ５−ａ）で表される化合物１０．０７部を１５分かけて添加し、５℃で３時間攪拌した後、２３℃で１時間、さらに、５０℃で３０時間攪拌した。得られた反応マスに、ｔｅｒｔ−ブチルメチルエーテル１５部及びイオン交換水１５部を加えて２３℃で３０分間攪拌した後、ろ過した。回収されたろ物に、ｔｅｒｔ−ブチルメチルエーテル２０部を加えて２３℃で３０分間攪拌した後、ろ過することにより、式（Ｉ−Ｘ４−ｃ）で表される塩８．８４部を得た。

式（Ｉ−Ｘ５−ｃ）で表される塩４．００部、メタノール４０部及び臭化ナトリウム１．００部を添加し、２３℃で１時間攪拌した。得られた混合溶液に、ジメチル硫酸１．３４部を添加し、２３℃で２４時間攪拌した。得られた反応マスを濃縮した後、得られた濃縮残に、ｔｅｒｔ−ブチルメチルエーテル２０部を加えて２３℃で３０分間攪拌した後、ろ過することにより、式（Ｉ−Ｘ５−ｄ）で表される塩２．８２部を得た。

式（Ｉ−Ｘ５−ｄ）で表される塩２．８２部、式（Ｉ−Ｘ５−ｅ）で表される化合物０．６１部及びクロロホルム２９部を添加し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ−Ｘ５−ｆ）で表される化合物０．０１部を添加した後、６０℃で５時間還流攪拌した後、濃縮した。得られた濃縮残に、ｔｅｒｔ−ブチルメチルエーテル１０部を加えて２３℃で３０分間攪拌し、上澄み液を除去し、濃縮することにより、式（Ｉ−Ｘ５）で表される塩１．１７部を得た。 Example 9: Synthesis of salt represented by formula (IX5)

5.00 parts of the compound represented by the formula (I-X5-b), 1.98 parts of iodine and 20.00 parts of sulfuric acid were added, and the mixture was stirred at 23 ° C. for 30 minutes. After cooling the obtained mixed solution to 5 ° C., 10.07 parts of the compound represented by the formula (I-X5-a) was added over 15 minutes, and the mixture was stirred at 5 ° C. for 3 hours and then at 23 ° C. The mixture was stirred for 1 hour and further at 50 ° C. for 30 hours. To the obtained reaction mass, 15 parts of tert-butyl methyl ether and 15 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes and then filtered. To the recovered filter medium, 20 parts of tert-butyl methyl ether was added, the mixture was stirred at 23 ° C. for 30 minutes, and then filtered to obtain 8.84 parts of a salt represented by the formula (I-X4-c). ..

4.00 parts of salt represented by the formula (I-X5-c), 40 parts of methanol and 1.00 parts of sodium bromide were added, and the mixture was stirred at 23 ° C. for 1 hour. To the obtained mixed solution, 1.34 parts of dimethyl sulfate was added, and the mixture was stirred at 23 ° C. for 24 hours. After concentrating the obtained reaction mass, 20 parts of tert-butyl methyl ether was added to the obtained concentrated residue, and the mixture was stirred at 23 ° C. for 30 minutes and then filtered to obtain the formula (I-X5-d). 2.82 parts of the salt represented was obtained.

2.82 parts of the salt represented by the formula (I-X5-d), 0.61 part of the compound represented by the formula (I-X5-e) and 29 parts of chloroform were added, and the mixture was stirred at 23 ° C. for 30 minutes. .. To the obtained mixed solution, 0.01 part of the compound represented by the formula (I-X5-f) was added, and the mixture was reflux-stirred at 60 ° C. for 5 hours and then concentrated. To the obtained concentrated residue, 10 parts of tert-butyl methyl ether was added, and the mixture was stirred at 23 ° C. for 30 minutes to remove the supernatant and concentrated to obtain 1.17 salt represented by the formula (IX5). I got a part.

MASS (ESI (+) Spectrum): M ⁺ 226.1
MASS (ESI (-) Spectrum): M ^- 111.0

式（Ｉ−Ｘ５）で表される塩０．７０部及びクロロホルム２０部を仕込んだ後、式（Ｉ−６−ａ）で表される塩２．３９部及びイオン交換水６部を仕込み、２３℃で１２時間攪拌した。得られた反応液を分液して有機層を取り出した。回収された有機層にイオン交換水１０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を２回繰り返した。得られた残渣を濃縮した後、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル１０部を加えて攪拌した後、上澄み液を除去した。得られた残渣を濃縮することにより、式（Ｉ−６０）で表される塩０．７８部を得た。 Example 10: Synthesis of salt represented by formula (I-60)

After charging 0.70 parts of salt represented by the formula (IX5) and 20 parts of chloroform, 2.39 parts of salt represented by the formula (I-6-a) and 6 parts of ion-exchanged water were charged. The mixture was stirred at 23 ° C. for 12 hours. The obtained reaction solution was separated and the organic layer was taken out. After adding 10 parts of ion-exchanged water to the recovered organic layer and stirring at 23 ° C. for 30 minutes, the liquid was separated and the organic layer was taken out. This washing operation was repeated twice. After concentrating the obtained residue, 10 parts of tert-butyl methyl ether was added to the obtained residue and stirred, and then the supernatant was removed. By concentrating the obtained residue, 0.78 parts of a salt represented by the formula (I-60) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 226.1
MASS (ESI (-) Spectrum): M ^- 467.1

式（Ｉ−Ｘ１）で表される塩３．２５部及びクロロホルム６０部を仕込んだ後、式（Ｉ−１−ａ）で表される塩９．２６部及びイオン交換水３０部を仕込み、２３℃で１２時間攪拌した。得られた反応液を分液して有機層を取り出した。回収された有機層にイオン交換水３０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を２回繰り返した。得られた残渣を濃縮した後、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌した後、上澄み液を除去した。得られた残渣を濃縮することにより、式（Ｉ−１）で表される塩４．２８部を得た。 Example 11: Synthesis of salt represented by formula (I-1)

After charging 3.25 parts of salt represented by the formula (IX1) and 60 parts of chloroform, 9.26 parts of salt represented by the formula (I-1-a) and 30 parts of ion-exchanged water were charged. The mixture was stirred at 23 ° C. for 12 hours. The obtained reaction solution was separated and the organic layer was taken out. After adding 30 parts of ion-exchanged water to the recovered organic layer and stirring at 23 ° C. for 30 minutes, the liquid was separated and the organic layer was taken out. This washing operation was repeated twice. After concentrating the obtained residue, 30 parts of tert-butyl methyl ether was added to the obtained residue and stirred, and then the supernatant was removed. By concentrating the obtained residue, 4.28 parts of a salt represented by the formula (I-1) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 199.1
MASS (ESI (-) Spectrum): M ^- 339.1

式（Ｉ−Ｘ１）で表される塩３．２５部及びクロロホルム６０部を仕込んだ後、式（Ｉ−１８−ａ）で表される塩９．２６部及びイオン交換水３０部を仕込み、２３℃で１２時間攪拌した。得られた反応液を分液して有機層を取り出した。回収された有機層にイオン交換水３０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を２回繰り返した。得られた残渣を濃縮した後、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌した後、上澄み液を除去した。得られた残渣を濃縮することにより、式（Ｉ−６１）で表される塩４．２８部を得た。 Example 12: Synthesis of salt represented by formula (I-61)

After charging 3.25 parts of salt represented by the formula (IX1) and 60 parts of chloroform, 9.26 parts of salt represented by the formula (I-18-a) and 30 parts of ion-exchanged water were charged. The mixture was stirred at 23 ° C. for 12 hours. The obtained reaction solution was separated and the organic layer was taken out. After adding 30 parts of ion-exchanged water to the recovered organic layer and stirring at 23 ° C. for 30 minutes, the liquid was separated and the organic layer was taken out. This washing operation was repeated twice. After concentrating the obtained residue, 30 parts of tert-butyl methyl ether was added to the obtained residue and stirred, and then the supernatant was removed. By concentrating the obtained residue, 4.28 parts of a salt represented by the formula (I-61) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 199.1
MASS (ESI (-) Spectrum): M ^- 339.1

Resin Synthesis The compounds (monomers) used in the synthesis of the resin (A) are shown below. Hereinafter, these compounds are referred to as "monomers (a1-1-3)" and the like according to their formula numbers.

Synthesis Example 1: Synthesis of resin A1 As a monomer, a monomer (a1-1-3), a monomer (a1-2-9), a monomer (a2-1-3), and a monomer (a3-4-2) are used. The molar ratio [monomer (a1-1-3): monomer (a1-2-9): monomer (a2-1-3): monomer (a3-4-2)] is 45: 14: 2.5: 38. The mixture was mixed so as to have a concentration of 5, and propylene glycol monomethyl ether acetate 1.5% by mass of the total amount of the monomers was added to prepare a solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 1 mol% and 3 mol%, respectively, based on the total amount of monomers, and these were heated at 73 ° C. for about 5 hours. bottom. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate a resin, and the resin was filtered. The obtained resin is dissolved again in propylene glycol monomethyl ether acetate, and the obtained solution is poured into a methanol / water mixed solvent to precipitate the resin, and the resin is filtered. the resin A1 having a molecular weight of 7.6 × 10 ³ was obtained in 68% yield. This resin A1 has the following structural units.

Synthesis Example 2: Synthesis of resin X1 A monomer (a4-1-7) was used as a monomer, and methyl isobutyl ketone 1.5% by mass of the total amount of the monomer was added to prepare a solution. Azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to this solution in an amount of 0.7 mol% and 2.1 mol%, respectively, based on the total amount of monomers, and these were added at 75 ° C. It was heated for about 5 hours. The reaction mixture obtained, the resin was precipitated by pouring into a large amount of methanol / water mixed solvent, the resin was filtered, to obtain a resin X1 of weight average molecular weight 1.7 × 10 ⁴ in 77% yield. This resin X1 has the following structural units.

Synthesis Example 3: Synthesis of Resin X2 Monomer (a5-1-1) and monomer (a4-0-12) are used as monomers, and their molar ratio [monomer (a5-1-1): monomer (a4-0-). 12)] was mixed so that the ratio was 50:50, and methyl isobutyl ketone, which was 1.2% by mass of the total amount of the monomers, was added to prepare a solution. Azobis (2,4-dimethylvaleronitrile) as an initiator was added to this solution in an amount of 3 mol% based on the total amount of monomers, and the mixture was heated at 70 ° C. for about 5 hours. The reaction mixture obtained, the resin was precipitated by pouring into a large amount of methanol / water mixed solvent, the resin was filtered, to obtain a resin X having a weight-average molecular weight 1.0 × 10 ⁴ in 91% yield. This resin X2 has the following structural units.

<Preparation of resist composition>
As shown in Table 4, each of the following components was mixed, and the obtained mixture was filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

<Resin>
A1, X1, X2: Resin A1, Resin X1, Resin X2
<Salt (I)>
I-1: Salt represented by the formula (I-1) I-2: Salt represented by the formula (I-2) I-6: Salt represented by the formula (I-6) I-26: Formula Salt represented by (I-26) I-30: Salt represented by formula (I-30) I-54: Salt represented by formula (I-54) I-60: Salt represented by formula (I-60) Salt represented by I-61: Salt represented by formula (I-61) <acid generator>
B1-21: Salt represented by the formula (B1-21) (synthesized according to an example of JP2012-224611)
B1-22: Salt represented by the formula (B1-22) (synthesized according to an example of JP2012-224611)
IX-1: Synthesized according to the examples of JP2012-224611.

<Compound (D)>
D1: (manufactured by Tokyo Chemical Industry Co., Ltd.)

<Solvent>
Propylene Glycol Monomethyl Ether Acetate 265 Parts Propylene Glycol Monomethyl Ether 20 Parts 2-Heptanone 20 Parts γ-Butyrolactone 3.5 Parts

<Manufacturing of resist pattern and its evaluation>
An organic antireflection film composition (ARC-29; manufactured by Nissan Chemical Co., Ltd.) is applied to a silicon wafer and baked at 205 ° C. for 60 seconds to produce organic reflection on the wafer with a film thickness of 78 nm. An anti-reflective film was formed. Next, the above resist composition was applied (spin coated) on the organic antireflection film so that the film thickness after drying was 85 nm. After coating, the silicon wafer was prebaked on a direct hot plate at the temperature listed in the “PB” column of Table 4 for 60 seconds to form a composition layer. A contact hole pattern (hole pitch 90 nm) was used on a silicon wafer on which a composition layer was formed with an ArF excimer stepper for immersion exposure (XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Anal XY polarized light). / Using a mask for forming a hole diameter of 55 nm), the exposure amount was changed stepwise for exposure. Ultrapure water was used as the immersion medium.
After the exposure, post-exposure baking was performed on a hot plate at the temperature listed in the “PEB” column of Table 4 for 60 seconds. Next, the composition layer on the silicon wafer was developed by the dynamic dispensing method at 23 ° C. for 20 seconds using butyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a developing solution to form a negative resist pattern. Manufactured.

In the resist pattern obtained after development, the exposure amount having a hole diameter of 50 nm formed by using the mask was defined as the effective sensitivity.

<CD uniformity (CDU) evaluation>
In the effective sensitivity, the hole diameter of the pattern formed by the mask having a hole diameter of 55 nm was measured 24 times for each hole, and the average value was taken as the average hole diameter of one hole. The standard deviation was obtained by measuring the average hole diameter of a pattern formed with a mask having a hole diameter of 55 nm at 400 points on the same wafer as a population.
"○" when the standard deviation is 1.70 nm or less,
When the standard deviation was larger than 1.70 nm, it was judged as “x”.
The results are shown in Table 5. The numbers in parentheses indicate the standard deviation (nm).

The resist composition containing the salt of the present invention has good CD uniformity of the obtained resist pattern, is suitable for microfabrication of semiconductors, and is extremely useful in industry.

Claims (4)

A salt represented by the formula (I).

[In formula (I),
R ¹ and R ² independently represent 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−. It may be replaced.
m and n each independently represent 2. When m is 2, the two R ^1s are the same or different, and when n is 2, the two R ^2s are the same or different.
X represents an oxygen atom.
Ar is selected from the group consisting of an aromatic hydrocarbon group having 6 to 36 carbon atoms having an electron-withdrawing group selected from the group consisting of a halogen group, a cyano group and a nitro group, or the group consisting of a halogen group, a cyano group and a nitro group. It represents a heteroaromatic hydrocarbon group having 6 to 36 carbon atoms and having an electron-withdrawing group.
A ^- represents an anion represented by the formula (I-A). ]

[In the formula (IA), L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and −CH ₂ − contained in the saturated hydrocarbon group is −O− or −CO−. The hydrogen atom contained in the saturated hydrocarbon group may be replaced with a fluorine atom or a hydroxy group.
Y represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a methyl group which may have a substituent or a substituent, and is contained in the alicyclic hydrocarbon group. CH ₂ − may be replaced with −O −, −SO _{2− or −CO−.}
Q ¹ and Q ² independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. ] A resist composition containing the salt according to claim 1 and a resin having an acid unstable group. The resist composition according to claim 2, further containing a salt that generates an acid having a weaker acidity than the acid generated from the acid generator. (1) A step of applying the resist composition according to claim 2 or 3 onto a substrate.
(2) A step of drying the applied composition to form a composition layer,
(3) Step of exposing the composition layer,
A method for producing a resist pattern, which comprises a step of (4) heating the composition layer after exposure and (5) a step of developing the composition layer after heating.