JP6963972B2 - Method for producing acid generator, resist composition and resist pattern - Google Patents

Description

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

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

Japanese Unexamined Patent Publication No. 2012-229199

In the resist composition containing the above salt, the mask error factor (MEF) of the obtained resist pattern may not always be satisfactory.

［式（Ｉ）中、
Ｑ^Ａ１及びＱ^Ａ２は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^ｂ１は、炭素数１〜２８の３価又は４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。
Ｒ^１は、水素原子、フッ素原子又はヒドロキシ基を表す。
ｍは０〜２のいずれかの整数を表し、ｎは１〜１２のいずれかの整数を表し、ｏは０又は１を表す。
ｎｎは、２又は３を表す。複数存在するＲ^１、ｍ、ｎ及びｏはそれぞれ、異なっていてもよいし、同一であってもよい。
Ｚ１^＋は、有機対イオンを表す。］
〔２〕Ｌ^ｂ１が、式（Ｌ^１−１）、式（Ｌ^１−２）又は式（Ｌ^１−３）で表される基である〔１〕記載のレジスト組成物。

［式（Ｌ^１−１）、式（Ｌ^１−２）及び式（Ｌ^１−３）中、
Ｘ^０は、単結合、フッ素原子を有していてもよい炭素数１〜１４の２価の脂肪族炭化水素基又は式（ａ−１）で表される基を表す。

（式（ａ−１）中、
ｓは０又は１を表す。
Ｘ¹⁰及びＸ^1１は、同一又は相異なり、酸素原子、カルボニル基、カルボニルオキシ基、オキシカルボニル基又はオキシカルボニルオキシ基を表す。
Ａ¹⁰及びＡ^1１はそれぞれ独立に、フッ素原子を有していてもよい炭素数１〜１２の２価の脂肪族炭化水素基を表す。
Ａ¹²は、単結合又はフッ素原子を有していてもよい炭素数１〜１２の２価の脂肪族炭化水素基を表す。
＊はＷ又は炭素原子との結合手を表す。）
Ｗは、炭素原子又は炭素数４〜１８の脂環式炭化水素基を表す。
Ｘ^１は、−Ｏ−＊１、−Ｏ−ＣＯ−＊１、−Ｏ−ＣＨ_２−＊１又は−Ｏ−ＣＨ_２−ＣＯ−Ｏ−＊１を表す。＊１は−（ＣＨ_２）_ｍ−（ＣＦ_２）_ｎ−（ＣＨ_２）_Ｏ−Ｒ^１との結合手を表す。
Ｘ^２は、−Ｏ−＊２、−Ｏ−ＣＯ−＊２、−Ｏ−ＣＨ_２−＊２又は−Ｏ−ＣＨ_２−ＣＯ−Ｏ−＊２を表す。＊２は−（ＣＨ_２）_ｍ−（ＣＦ_２）_ｎ−（ＣＨ_２）_Ｏ−Ｒ^１との結合手を表す。
Ｘ^３は、−Ｏ−＊１又は−Ｏ−ＣＨ_２−ＣＯ−Ｏ−＊１を表す。＊１は−（ＣＨ_２）_ｍ−（ＣＦ_２）_ｎ−（ＣＨ_２）_Ｏ−Ｒ^１との結合手を表す。
Ｘ^４は、−Ｏ−＊２又は−Ｏ−ＣＨ_２−ＣＯ−Ｏ−＊２を表す。＊２は−（ＣＨ_２）_ｍ−（ＣＦ_２）_ｎ−（ＣＨ_２）_Ｏ−Ｒ^１との結合手を表す。
Ｘ^５は、−Ｏ−＊１、−Ｏ−ＣＯ−＊１又は−Ｏ−ＣＨ_２−＊１を表す。＊１は−（ＣＨ_２）_ｍ−（ＣＦ_２）_ｎ−（ＣＨ_２）_Ｏ−Ｒ^１との結合手を表す。
Ｘ^６は、−Ｏ−＊２、−Ｏ−ＣＯ−＊２又は−Ｏ−ＣＨ_２−＊２を表す。＊２は−（ＣＨ_２）_ｍ−（ＣＦ_２）_ｎ−（ＣＨ_２）_Ｏ−Ｒ^１との結合手を表す。
＊Ｌ０は−Ｃ（Ｑ^Ａ１）（Ｑ^Ａ２）−との結合手を表す。
ｍ１、ｍ２、ｍ３、ｍ４及びｍ５は、それぞれ独立に、０〜６のいずれかの整数を表す。
Ｒ^Ｌは、水素原子又はフッ素原子を有していてもよい炭素数１〜１４の脂肪族炭化水素基を表す。
＊Ｌ１及び＊Ｌ２は、−（ＣＨ_２）ｍ−（ＣＦ_２）ｎ−（ＣＨ_２）ｏ−Ｒ^１との結合手を表す。］
〔３〕〔１〕又は〔２〕記載の塩を含有する酸発生剤。
〔４〕〔３〕記載の酸発生剤と、酸不安定基を有する構造単位を含む樹脂とを含有するレジスト組成物。
〔５〕フッ素原子を有する構造単位を含む樹脂をさらに含有する〔４〕記載のレジスト組成物。
〔６〕酸発生剤から発生する酸よりも酸性度の弱い酸を発生する塩をさらに含有する〔４〕又は〔５〕記載のレジスト組成物。
〔７〕（１）［４］〜［６］のいずれか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).

[In formula (I),
Q ^A1 and Q ^A2 each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
L ^b1 represents a trivalent or tetravalent saturated hydrocarbon group having 1 to 28 carbon atoms, and -CH _2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-. The hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
R ¹ represents a hydrogen atom, a fluorine atom or a hydroxy group.
m represents any integer from 0 to 2, n represents any integer from 1 to 12, and o represents 0 or 1.
nn represents 2 or 3. R ¹ there are a ^plurality, m, n and o are each, it may be different, may be the same.
Z1 ⁺ represents an organic counterion. ]
[2] ^{L b1} is the formula ^(L 1 -1), formula ^(L 1 -2) or a group represented by the formula ^(L 1 -3) [1] resist composition.

Wherein ^(L 1 -1), formula ^(L 1 -2) and formula ^(L 1 -3),
X ⁰ represents a divalent aliphatic hydrocarbon group having 1 to 14 carbon atoms which may have a single bond and a fluorine atom or a group represented by the formula (a-1).

(In equation (a-1),
s represents 0 or 1.
X ¹⁰ and X ¹¹ are the same or different and represent an oxygen atom, a carbonyl group, a carbonyloxy group, an oxycarbonyl group or an oxycarbonyloxy group.
A ¹⁰ and A ¹¹ each independently represent a divalent aliphatic hydrocarbon group having 1 to 12 carbon atoms which may have a fluorine atom.
A ¹² represents a divalent aliphatic hydrocarbon group having 1 to 12 carbon atoms which may have a single bond or a fluorine atom.
* Represents a bond with W or a carbon atom. )
W represents a carbon atom or an alicyclic hydrocarbon group having 4 to 18 carbon atoms.
X ¹ represents -O- * 1, -O-CO- * 1, -O-CH _2- * 1 or -O-CH ₂ --CO-O- * 1. * 1 represents _{- (CH 2)} bond to ^{_{O -R 1 - (CH 2)}} m - (CF 2) n.
X ² represents -O- * 2, -O-CO- * 2, -O-CH _2- * 2, or -O-CH _2- CO-O- * 2. * 2 represents _{- (CH 2)} bond to ^{_{O -R 1 - (CH 2)}} m - (CF 2) n.
X ³ represents -O- * 1 or -O-CH _2- CO-O- * 1. * 1 represents _{- (CH 2)} bond to ^{_{O -R 1 - (CH 2)}} m - (CF 2) n.
X ⁴ represents -O- * 2 or -O-CH _2- CO-O- * 2. * 2 represents _{- (CH 2)} bond to ^{_{O -R 1 - (CH 2)}} m - (CF 2) n.
X ⁵ represents -O- * 1, -O-CO- * 1 or -O-CH _2- * 1. * 1 represents _{- (CH 2)} bond to ^{_{O -R 1 - (CH 2)}} m - (CF 2) n.
X ⁶ represents -O- * 2, -O-CO- * 2 or -O-CH _2- * 2. * 2 represents _{- (CH 2)} bond to ^{_{O -R 1 - (CH 2)}} m - (CF 2) n.
* L0 represents a bond with -C (Q ^A1 ) (Q ^A2)-.
m1, m2, m3, m4 and m5 each independently represent an integer of 0 to 6.
^RL represents an aliphatic hydrocarbon group having 1 to 14 carbon atoms which may have a hydrogen atom or a fluorine atom.
* L1 and * L2 represent a bond with _{− (CH 2} ) m- (CF ₂ ) n- (CH ₂ ) o-R ^1. ]
[3] An acid generator containing the salt according to [1] or [2].
[4] A resist composition containing the acid generator according to [3] and a resin containing a structural unit having an acid unstable group.
[5] The resist composition according to [4], which further contains a resin containing a structural unit having a fluorine atom.
[6] The resist composition according to [4] or [5], which further contains a salt that generates an acid having a weaker acidity than the acid generated from the acid generator.
[7] (1) A step of applying the resist composition according to any one of [4] to [6] 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 is a salt capable of producing a resist pattern of good mask error factor (MEF).

As used herein, the term "(meth) acrylate" means "at least one of acrylate and methacrylate," respectively. Notations such as "(meta) acrylic acid" and "(meta) acryloyl" have the same meaning.
Further, unless otherwise specified, a group capable of taking a linear, branched and / or ring such as an "aliphatic hydrocarbon group" includes any of them. The "aromatic hydrocarbon group" also includes a group in which a hydrocarbon group is bonded to an aromatic ring. If a steric isomer is present, it includes all steric isomers.
In the present specification, the "solid content of the resist composition" means the total amount of the components excluding the solvent (E) described later from the total amount of the resist composition.

［式（Ｉ）中、
Ｑ^Ａ１及びＱ^Ａ２は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^ｂ１は、炭素数１〜２８の３価又は４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。
Ｒ^１は、水素原子、フッ素原子又はヒドロキシ基を表す。
ｍは０〜２のいずれかの整数を表し、ｎは１〜１２のいずれかの整数を表し、ｏは０又は１を表す。
ｎｎは、２又は３を表す。複数存在するＲ^１、ｍ、ｎ及びｏはそれぞれ、異なっていてもよいし、同一であってもよい。
Ｚ１^＋は、有機対イオンを表す。］
塩（Ｉ）のうち、正電荷を有する側を「有機カチオン」と、負電荷を有する側を「スルホン酸アニオン」と、それぞれ称することがある。 <Salt>
The salt of the present invention is a salt represented by the formula (I) (hereinafter, may be referred to as "salt (I)").

[In formula (I),
Q ^A1 and Q ^A2 each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
L ^b1 represents a trivalent or tetravalent saturated hydrocarbon group having 1 to 28 carbon atoms, and -CH _2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-. The hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
R ¹ represents a hydrogen atom, a fluorine atom or a hydroxy group.
m represents any integer from 0 to 2, n represents any integer from 1 to 12, and o represents 0 or 1.
nn represents 2 or 3. R ¹ there are a ^plurality, m, n and o are each, it may be different, may be the same.
Z1 ⁺ represents an organic counterion. ]
Of the salt (I), the side having a positive charge may be referred to as an "organic cation", and the side having a negative charge may be referred to as a "sulfonic acid anion".

The perfluoroalkyl group Q ^A1 and Q ^A2, 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.
Q ^A1 and ^{Q A2} each independently is preferably a fluorine atom or a trifluoromethyl ^{group, Q A1} and ^{Q A2} is more preferably both fluorine atoms.

Examples of the trivalent and tetravalent saturated hydrocarbon groups of L ^b1 include groups from which one or two hydrogen atoms have been removed at arbitrary positions of the divalent saturated hydrocarbon groups. Examples of the divalent saturated hydrocarbon group include a linear alkanediyl group, a branched alkanediyl group, and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, among these groups. It may be a combination of two or more types.
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.

［式（Ｌ^１−１）、式（Ｌ^１−２）及び式（Ｌ^１−３）中、
Ｘ^０は、単結合、フッ素原子を有していてもよい炭素数１〜１４の２価の脂肪族炭化水素基又は式（ａ−１）で表される基を表す。

（式（ａ−１）中、
ｓは０又は１を表す。
Ｘ¹⁰及びＸ^1１は、同一又は相異なり、酸素原子、カルボニル基、カルボニルオキシ基、オキシカルボニル基又はオキシカルボニルオキシ基を表す。
Ａ¹⁰及びＡ^1１はそれぞれ独立に、フッ素原子を有していてもよい炭素数１〜１２の２価の脂肪族炭化水素基を表す。
Ａ¹²は、単結合又はフッ素原子を有していてもよい炭素数１〜１２の２価の脂肪族炭化水素基を表す。
＊はＷ又は炭素原子との結合手を表す。）
Ｗは、炭素原子又は炭素数４〜１８の脂環式炭化水素基を表す。
Ｘ^１は、−Ｏ−＊１、−Ｏ−ＣＯ−＊１、−Ｏ−ＣＨ_２−＊１又は−Ｏ−ＣＨ_２−ＣＯ−Ｏ−＊１を表す。＊１は−（ＣＨ_２）_ｍ−（ＣＦ_２）_ｎ−（ＣＨ_２）_Ｏ−Ｒ^１との結合手を表す。
Ｘ^２は、−Ｏ−＊２、−Ｏ−ＣＯ−＊２、−Ｏ−ＣＨ_２−＊２又は−Ｏ−ＣＨ_２−ＣＯ−Ｏ−＊２を表す。＊２は−（ＣＨ_２）_ｍ−（ＣＦ_２）_ｎ−（ＣＨ_２）_Ｏ−Ｒ^１との結合手を表す。
Ｘ^３は、−Ｏ−＊１又は−Ｏ−ＣＨ_２−ＣＯ−Ｏ−＊１を表す。＊１は−（ＣＨ_２）_ｍ−（ＣＦ_２）_ｎ−（ＣＨ_２）_Ｏ−Ｒ^１との結合手を表す。
Ｘ^４は、−Ｏ−＊２又は−Ｏ−ＣＨ_２−ＣＯ−Ｏ−＊２を表す。＊２は−（ＣＨ_２）_ｍ−（ＣＦ_２）_ｎ−（ＣＨ_２）_Ｏ−Ｒ^１との結合手を表す。
Ｘ^５は、−Ｏ−＊１、−Ｏ−ＣＯ−＊１又は−Ｏ−ＣＨ_２−＊１を表す。＊１は−（ＣＨ_２）_ｍ−（ＣＦ_２）_ｎ−（ＣＨ_２）_Ｏ−Ｒ^１との結合手を表す。
Ｘ^６は、−Ｏ−＊２、−Ｏ−ＣＯ−＊２又は−Ｏ−ＣＨ_２−＊２を表す。＊２は−（ＣＨ_２）_ｍ−（ＣＦ_２）_ｎ−（ＣＨ_２）_Ｏ−Ｒ^１との結合手を表す。
＊Ｌ０は−Ｃ（Ｑ^Ａ１）（Ｑ^Ａ２）−との結合手を表す。
ｍ１、ｍ２、ｍ３、ｍ４及びｍ５は、それぞれ独立に、０〜６の整数を表す。
Ｒ^Ｌは、水素原子又はフッ素原子を有していてもよい炭素数１〜１４の脂肪族炭化水素基を表す。
＊Ｌ１及び＊Ｌ２は、−（ＣＨ_２）ｍ−（ＣＦ_２）ｎ−（ＣＨ_２）ｏ−Ｒ^１との結合手を表す。］
ただし、これらの炭素数の最大合計数は２８である。 The nn is preferably 2.
The L ^b1, the following formulas ^(L 1 -1), is preferably a group represented by the formula ^(L 1 -2) or formula ^(L 1 -3).

Wherein ^(L 1 -1), formula ^(L 1 -2) and formula ^(L 1 -3),
X ⁰ represents a divalent aliphatic hydrocarbon group having 1 to 14 carbon atoms which may have a single bond and a fluorine atom or a group represented by the formula (a-1).

(In equation (a-1),
s represents 0 or 1.
X ¹⁰ and X ¹¹ are the same or different and represent an oxygen atom, a carbonyl group, a carbonyloxy group, an oxycarbonyl group or an oxycarbonyloxy group.
A ¹⁰ and A ¹¹ each independently represent a divalent aliphatic hydrocarbon group having 1 to 12 carbon atoms which may have a fluorine atom.
A ¹² represents a divalent aliphatic hydrocarbon group having 1 to 12 carbon atoms which may have a single bond or a fluorine atom.
* Represents a bond with W or a carbon atom. )
W represents a carbon atom or an alicyclic hydrocarbon group having 4 to 18 carbon atoms.
X ¹ represents -O- * 1, -O-CO- * 1, -O-CH _2- * 1 or -O-CH ₂ --CO-O- * 1. * 1 represents _{- (CH 2)} bond to ^{_{O -R 1 - (CH 2)}} m - (CF 2) n.
X ² represents -O- * 2, -O-CO- * 2, -O-CH _2- * 2, or -O-CH _2- CO-O- * 2. * 2 represents _{- (CH 2)} bond to ^{_{O -R 1 - (CH 2)}} m - (CF 2) n.
X ³ represents -O- * 1 or -O-CH _2- CO-O- * 1. * 1 represents _{- (CH 2)} bond to ^{_{O -R 1 - (CH 2)}} m - (CF 2) n.
X ⁴ represents -O- * 2 or -O-CH _2- CO-O- * 2. * 2 represents _{- (CH 2)} bond to ^{_{O -R 1 - (CH 2)}} m - (CF 2) n.
X ⁵ represents -O- * 1, -O-CO- * 1 or -O-CH _2- * 1. * 1 represents _{- (CH 2)} bond to ^{_{O -R 1 - (CH 2)}} m - (CF 2) n.
X ⁶ represents -O- * 2, -O-CO- * 2 or -O-CH _2- * 2. * 2 represents _{- (CH 2)} bond to ^{_{O -R 1 - (CH 2)}} m - (CF 2) n.
* L0 represents a bond with -C (Q ^A1 ) (Q ^A2)-.
m1, m2, m3, m4 and m5 each independently represent an integer of 0 to 6.
^RL represents an aliphatic hydrocarbon group having 1 to 14 carbon atoms which may have a hydrogen atom or a fluorine atom.
* L1 and * L2 represent a bond with _{− (CH 2} ) m- (CF ₂ ) n- (CH ₂ ) o-R ^1. ]
However, the maximum total number of these carbon atoms is 28.

Examples of the group represented by the formula (L 1 ^-1), for example, include the following.

Examples of the group represented by the formula (L ^{1-2) include the following.}

Examples of the divalent group represented by the formula (L ^{1-3) include the following.}

* ^2- (CH ₂ ) _m- (CF ₂ ) _n- (CH ₂ ) _o- R ¹ (* ² represents a bond with L ^b1 ) includes, for example, a group represented by the following. Can be mentioned.

Examples of the salt anion represented by the formula (I) include the sulfonic acid anions shown below.

Examples of the cation Z1 ⁺ of the formula (I) include an organic onium cation, for example, an organic sulfonium cation, an organic iodine cation, an organic ammonium cation, a benzothiazolium cation, an organic phosphonium cation, and the like, and an organic sulfonium cation or an organic cation is preferable. It is an iodonium cation, more preferably an aryl sulfonium cation.
Among them, a cation represented by any of the formulas (b2-1) to (b2-4) (hereinafter, may be referred to as “cation (b2-1)” or the like depending on the formula number) is preferable.

In equations (b2-1) to (b2-4),
R ^{b4 to} R ^b6 independently represent an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms. The hydrogen atom contained in the aliphatic hydrocarbon group is a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. It may be substituted, and the hydrogen atom contained in the alicyclic hydrocarbon group is substituted with a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an acyl group having 2 to 4 carbon atoms, or a glycidyloxy group. The hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group, or an alkoxy group having 1 to 12 carbon atoms.
R ^b4 and R ^b5 may be combined to form a ring containing a sulfur atom to which they are bonded, and the methylene group contained in the ring may be replaced with an oxygen atom, a sulfinyl group or a carbonyl group. ..

R ^b7 and R ^b8 independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0 to 5.
When m2 is 2 or more, the plurality of R ^b7s may be the same or different, and when n2 is 2 or more, the plurality of R ^b8s may be the same or different.

R ^b9 and R ^b10 independently represent an aliphatic hydrocarbon group having 1 to 36 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms.
R ^b9 and R ^b10 may be combined to form a ring containing a sulfur atom to which they are bonded, and the methylene group contained in the ring may be replaced with an oxygen atom, a sulfinyl group or a carbonyl group. ..
R ^b11 represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^b12 represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and is contained in the aliphatic hydrocarbon group. The hydrogen atom may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group may be an alkoxy group having 1 to 12 carbon atoms or 1 to 12 carbon atoms. It may be substituted with 12 alkylcarbonyloxy groups.
R ^b1 and R ^b12 may be combined to form a ring containing -CH-CO- to which they are bonded, and the methylene group contained in the ring may be an oxygen atom, a sulfinyl group or a carbonyl group. It may be replaced.

R ^{b13 to} R ^b18 independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
L ^b31 represents a sulfur atom or an oxygen atom.
o2, p2, s2, and t2 each independently represent an integer of 0-5.
q2 and r2 each independently represent an integer of 0-4.
u2 represents 0 or 1.
When o2 is 2 or more, a plurality of R ^b13s are the same or different, when p2 is 2 or more, a plurality of R ^b14s are the same or different, and when q2 is 2 or more, a plurality of R ^b15s are the same or different. when r2 is 2 or more, plural R ^b16 same or different, when s2 is 2 or more, plural R ^b17 same or different, when t2 is 2 or more, plural R ^b18 same or different different.

特に、Ｒ^b9〜Ｒ^b12の脂環式炭化水素基は、好ましくは炭素数３〜１８、より好ましくは炭素数４〜１２である。 The aliphatic hydrocarbon 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, an n-pentyl group, an n-hexyl group and an n-octyl group. Alkyl groups of groups and 2-ethylhexyl groups can be mentioned. In particular, ^{the aliphatic hydrocarbon groups of R b9 to} R ^b12 preferably have 1 to 12 carbon atoms.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon group includes a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclo. Cycloalkyl groups such as heptyl group, cyclooctyl group and cyclodecyl group can be mentioned. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups.

In particular, ^{the alicyclic hydrocarbon groups of R b9 to} R ^b12 preferably have 3 to 18 carbon atoms, and more preferably 4 to 12 carbon atoms.

Examples of the alicyclic hydrocarbon group in which the hydrogen atom is substituted with an aliphatic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a 2-alkyladamantan-2-yl group, a methylnorbornyl group, an isobornyl group and the like. Can be mentioned. In the alicyclic hydrocarbon group in which the hydrogen atom is substituted with an aliphatic hydrocarbon group, the total number of carbon atoms of the alicyclic hydrocarbon group and the aliphatic hydrocarbon group is preferably 20 or less.

Examples of the aromatic hydrocarbon group include a phenyl group, a tolyl group, a xsilyl group, a cumenyl group, a mesityl group, a p-ethylphenyl group, a p-tert-butylphenyl group, a p-cyclohexylphenyl group and a p-adamantylphenyl group. , Biphenylyl group, naphthyl group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group and other aryl groups.
When the aromatic hydrocarbon group contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, the aliphatic hydrocarbon group having 1 to 18 carbon atoms and the alicyclic hydrocarbon group having 3 to 18 carbon atoms are used. Groups are preferred.
Examples of the aromatic hydrocarbon group in which the hydrogen atom is substituted with an alkoxy group include a p-methoxyphenyl group.
Examples of the aliphatic hydrocarbon group in which the hydrogen atom is substituted with an aromatic hydrocarbon group include an aralkyl group such as a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group and a naphthylethyl 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 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.
Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropylcarbonyloxy group, an n-butylcarbonyloxy group, a sec-butylcarbonyloxy group, and a tert-butylcarbonyloxy group. Examples thereof include a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group and a 2-ethylhexylcarbonyloxy group.

The ^{ring containing a sulfur atom formed by R b4} and R ^b5 together may be a monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated ring. .. Examples of this ring include a ring having 3 to 18 carbon atoms, preferably a ring having 4 to 18 carbon atoms. The ring containing a sulfur atom includes a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring. The following rings are mentioned.

The ^{ring formed by R b9} and R ^b10 together may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. This ring may be a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring. For example, a thiolan-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, a 1,4-oxatian-4-ium ring and the like can be mentioned.
The ^{ring formed by R b11} and R ^b12 together may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. This ring may be a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring. Examples thereof include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

Among the cations (b2-1) to cations (b2-4), the cation (b2-1) is preferable.

Examples of the cation (b2-1) include the following cations.

Examples of the cation (b2-2) include the following cations.

Examples of the cation (b2-3) include the following cations.

Examples of the cation (b2-4) include the following cations.

The salt (I) is a combination of the above-mentioned sulfonic acid anion and organic cation. These anions and cations can be combined arbitrarily. Specific examples of the salt (I) are shown in Table 1.
In Table 1, the salt (I-1) is a salt composed of a sulfonic acid anion represented by the formula (Ia-1) and a cation represented by the formula (b2-c-1), and is a salt shown below. Represents.

Among them, the salt (I) is salt (I-1), salt (I-2), salt (I-5) to salt (I-8), salt (I-11) to salt (I-13). , Salt (I-24), Salt (I-25), Salt (I-28) -Salt (I-31), Salt (I-34) -Salt (I-36), Salt (I-47), Salt (I-48), salt (I-51) to salt (I-54), salt (I-57) to salt (I-59), salt (I-70), salt (I-71), salt (I-74) -salt (I-77), salt (I-80) -salt (I-82), salt (I-93), salt (I-94), salt (I-97) -salt ( I-100), salt (I-103) to salt (I-105), salt (I-116), salt (I-117), salt (I-120) to salt (I-123), salt (I) -126) to salt (I-128), salt (I-139), salt (I-140), salt (I-143) to salt (I-146), salt (I-149) to salt (I- 151), salt (I-162) to salt (I-203) are preferable.

Salts L ^b1 is represented by the formula ^(L 1 -1) in group a is a salt represented (I01) [Formula (I01) (I), hereinafter also referred to as "salt (I01)". ] Can be produced, for example, by reacting a salt represented by the formula (I01-a) with a compound represented by the formula (I01-b) in a solvent.

この反応の溶媒としては、クロロホルム、アセトニトリルなどが用いられる。
反応温度は通常５℃〜８０℃であり、反応時間は通常０．５時間〜２４時間である。
式（Ｉ０１−ｃ）で表される塩としては、以下で表される塩などが挙げられ、特開２００８−１２７３６７号公報に記載された方法で製造することができる。

The salt represented by the formula (I01-a) can be obtained by reacting the salt represented by the formula (I01-c) with the compound represented by the formula (I01-d) in a solvent. can.

Chloroform, acetonitrile and the like are used as the solvent for this reaction.
The reaction temperature is usually 5 ° C to 80 ° C, and the reaction time is usually 0.5 to 24 hours.
Examples of the salt represented by the formula (I01-c) include salts represented by the following, which can be produced by the method described in JP-A-2008-127365.

Examples of the compound represented by the formula (I01-b) include compounds represented by the following, which can be easily synthesized by a known synthesis method.

Salts L ^b1 is represented by the formula ^(L 1 -2) in group a is a salt represented (I02) [Formula (I02) (I), hereinafter also referred to as "salt (I02)". ] Can be produced, for example, by reacting a salt represented by the formula (I01-a) with a compound represented by the formula (I02-b) in a solvent.

Chloroform, acetonitrile and the like are used as the solvent for this reaction.
The reaction temperature is usually 5 ° C to 80 ° C, and the reaction time is usually 0.5 to 24 hours.
Examples of the compound represented by the formula (I02-b) include compounds represented by the following, which can be easily synthesized by a known synthesis method.

A salt (I02A) in which ^{L b1} is a group represented by the formula (L ^{1-2 ), X 0} is a group represented by the formula (a-1), and X ^{11 is an oxycarbonyloxy group.} The salt (I) represented by (I02A) is hereinafter referred to as "salt (I02A)" in some cases. ] Can also be produced, for example, by reacting a salt represented by the formula (I02A-a) with a compound represented by the formula (I02A-b).

式（Ｉ０２Ａ−ｂ）で表される化合物としては、例えば、以下で表される化合物が挙げられ、公知の合成方法で容易に合成することができる。

Chloroform, acetonitrile and the like are used as the solvent for this reaction.
The reaction temperature is usually 5 ° C to 80 ° C, and the reaction time is usually 0.5 to 24 hours.
Examples of the salt represented by the formula (I02A-a) include salts represented by the following, which can be produced by the method described in JP2012-72109.

Examples of the compound represented by the formula (I02A-b) include compounds represented by the following, which can be easily synthesized by a known synthesis method.

Salt (I03) on which L ^b1 is a group represented by the formula (L ^1-3 ) [Salt (I) represented by the formula (I03), hereinafter referred to as "salt (I03)" in some cases. ] Is produced, for example, by reacting the compound represented by the formula (I03-b) with carbonyldiimidazole in a solvent and then further reacting with the salt represented by the formula (I03-a). be able to.

Chloroform, acetonitrile and the like are used as the solvent for this reaction.
The reaction temperature is usually 5 ° C to 80 ° C, and the reaction time is usually 0.5 to 24 hours.
Examples of the salt represented by the formula (I03-a) include salts represented by the following, which can be produced by the method described in JP-A-2012-193170.

Examples of the compound represented by the formula (I03-b) include compounds represented by the following, which can be easily synthesized by a known synthesis method.

で表される基である塩（Ｉ）〔式（Ｉ１）で表される塩（Ｉ）、以下、場合により「塩（Ｉ１）」という。〕は、例えば、式（Ｉ１−ａ）で表される塩と、式（Ｉ１−ｂ）で表される化合物とを、溶媒中で反応させることにより製造することができる。

（式中、全ての符号は、それぞれ前記と同じ意味を表す。）
この反応の溶媒としては、クロロホルム、アセトニトリルなどが用いられる。
反応温度は通常５℃〜８０℃であり、反応時間は通常０．５時間〜２４時間である。 L ^b1 is the following formula

Salt (I) which is a group represented by (Salt (I) represented by formula (I1), hereinafter referred to as "salt (I1)" in some cases. ] Can be produced, for example, by reacting a salt represented by the formula (I1-a) with a compound represented by the formula (I1-b) in a solvent.

(In the formula, all the symbols have the same meanings as described above.)
Chloroform, acetonitrile and the like are used as the solvent for this reaction.
The reaction temperature is usually 5 ° C to 80 ° C, and the reaction time is usually 0.5 to 24 hours.

この反応の溶媒としては、クロロホルムなどが用いられる。
反応温度は通常５℃〜８０℃であり、反応時間は通常０．５時間〜２４時間である。
式（Ｉ１−ｃ）で表される化合物としては、以下で表される塩などが挙げられ、特開２００８−１２７３６７号公報に記載された方法で製造することができる。

The compound represented by the formula (I1-a) can be obtained by reacting the salt represented by the formula (I1-c) with the compound represented by the formula (I1-d) in a solvent. can.

Chloroform or the like is used as the solvent for this reaction.
The reaction temperature is usually 5 ° C to 80 ° C, and the reaction time is usually 0.5 to 24 hours.
Examples of the compound represented by the formula (I1-c) include salts represented by the following, which can be produced by the method described in JP-A-2008-127365.

この反応の触媒としては、炭酸カリウム、ヨウ化カリウムなどが用いられる。
この反応の溶媒としては、ジメチルホルムアミド、クロロホルム、アセトニトリルなどが用いられる。
反応温度は通常５℃〜８０℃であり、反応時間は通常０．５時間〜２４時間である。 The compound represented by the formula (I1-b) is such that the compound represented by the formula (I1-e) and the compound represented by the formula (I1-f) are reacted in a solvent in the presence of a catalyst. Can be obtained by

Potassium carbonate, potassium iodide and the like are used as catalysts for this reaction.
As the solvent for this reaction, dimethylformamide, chloroform, acetonitrile and the like are used.
The reaction temperature is usually 5 ° C to 80 ° C, and the reaction time is usually 0.5 to 24 hours.

Examples of the compound represented by the formula (I1-f) include compounds represented by the following, which are easily available on the market.

で表される基である塩（Ｉ）〔式（Ｉ２）で表される塩（Ｉ）、以下、場合により「塩（Ｉ２）」という。〕は、例えば、式（Ｉ２−ａ）で表される塩と、式（Ｉ２−ｂ１）で表される化合物又は式（Ｉ２−ｂ２）で表される化合物とを、塩基触媒の存在下、溶媒中で反応させることにより製造することができる。

（式中、全ての符号は、それぞれ前記と同じ意味を表す。）
この反応の溶媒としては、クロロホルム、アセトニトリルなどが用いられる。
塩基触媒としては、ピリジンなどが用いられる。
反応温度は通常５℃〜８０℃であり、反応時間は通常０．５時間〜２４時間である。
式（Ｉ２−ｂ１）で表される化合物としては、以下で表される化合物等が挙げられ、市場から容易に入手できる。

式（Ｉ２−ｂ２）で表される化合物としては、以下で表される化合物等が挙げられ、市場から容易に入手できる。

Further, L ^b1 is the following equation.

Salt (I) which is a group represented by (Salt (I) represented by formula (I2), hereinafter referred to as "salt (I2)" in some cases. ] Is, for example, a salt represented by the formula (I2-a) and a compound represented by the formula (I2-b1) or a compound represented by the formula (I2-b2) in the presence of a base catalyst. It can be produced by reacting in a solvent.

(In the formula, all the symbols have the same meanings as described above.)
Chloroform, acetonitrile and the like are used as the solvent for this reaction.
As the base catalyst, pyridine or the like is used.
The reaction temperature is usually 5 ° C to 80 ° C, and the reaction time is usually 0.5 to 24 hours.
Examples of the compound represented by the formula (I2-b1) include compounds represented by the following, which are easily available on the market.

Examples of the compound represented by the formula (I2-b2) include compounds represented by the following, which are easily available on the market.

（式中、全ての符号は、それぞれ前記と同じ意味を表す。）
この反応の触媒としては、炭酸カリウム、ヨウ化カリウムなどが用いられる。
この反応の溶媒としては、クロロホルム、アセトニトリルなどが用いられる。
反応温度は通常５℃〜８０℃であり、反応時間は通常０．５時間〜２４時間である。 The compound represented by the formula (I2-a) is a reaction of a compound represented by the formula (I1-c) and a compound represented by the formula (I2-c) in a solvent in the presence of a catalyst. Can be obtained by

(In the formula, all the symbols have the same meanings as described above.)
Potassium carbonate, potassium iodide and the like are used as catalysts for this reaction.
Chloroform, acetonitrile and the like are used as the solvent for this reaction.
The reaction temperature is usually 5 ° C to 80 ° C, and the reaction time is usually 0.5 to 24 hours.

[Acid generator]
The acid generator of the present invention is an acid generator containing a salt (I). The acid generator of the present invention may contain the salt (I) alone, or may contain two or more kinds of the salt (I).
The acid generator of the present invention may contain an acid generator known in the resist field (hereinafter, may be referred to as “acid generator (B)”) other than the salt (I).
When the salt (I) and the acid generator (B) are contained as the acid generator, the ratio of the contents of the salt (I) and the acid generator (B) (mass ratio; salt (I): acid generation The agent (B)) is usually 1:99 to 99: 1, preferably 2:98 to 98: 2, more preferably 5:95 to 95: 5, and even more preferably 10:90 to 90:10. ..

[Resist composition]
The resist composition of the present invention contains a resin having an acid unstable group (hereinafter sometimes referred to as "resin (A)") and the above-mentioned acid generator containing a salt (I). Here, the "acid-unstable group" is a structural unit having a leaving group, the leaving group being removed by contact with an acid, and the constituent unit having a hydrophilic group (for example, a hydroxy group or a carboxy group). Means the group that converts to.
The resist composition further preferably contains a quencher (hereinafter sometimes referred to as "quencher (C)") and preferably contains a solvent (hereinafter sometimes referred to as "solvent (E)"). ..

<Acid generator>
In the resist composition of the present invention, the content of the salt (I) is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, based on the resin (A).

<Acid generator (B)>
The acid generator is classified into a nonionic type and an ionic type, and any of the acid generator (B) of the resist composition of the present invention may be used. Nonionic acid generators include organic halides and sulfonate esters (eg 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4). -Sulfonates), sulfones (eg, disulfones, ketosulfones, sulfonyldiazomethanes) and the like. Examples of the ionic acid generator include an ionic acid generator composed of a combination of a known cation and a known anion, and an onium salt containing an onium cation (for example, a diazonium salt, a phosphonium salt, a sulfonium salt, an iodonium salt) is typical. Is the target. Examples of the onium salt anion include a sulfonic acid anion, a sulfonylimide anion, and a sulfonylmethide anion.

Examples of the acid generator (B) include Japanese Patent Application Laid-Open No. 63-26653, Japanese Patent Application Laid-Open No. 55-164824, Japanese Patent Application Laid-Open No. 62-69263, Japanese Patent Application Laid-Open No. 63-146038, Japanese Patent Application Laid-Open No. 63-163452, and Japanese Patent Application Laid-Open No. 63-163452. Kaisho 62-153853, Japanese Patent Application Laid-Open No. 63-146029, US Patent No. 3,779,778, US Patent No. 3,849,137, German Patent No. 3914407, European Patent No. 126,712, etc. The compound that generates an acid by radiation, the acid generator described in Japanese Patent Application Laid-Open No. 2013-68914, Japanese Patent Application Laid-Open No. 2013-3155, Japanese Patent Application Laid-Open No. 2013-1905, and the like can be used. Moreover, you may use the compound produced by the known method.

The acid generator (B) preferably contains an aryl sulfonium cation, and formulas (B1-1) to (B1-3), formulas (B1-5) to (B1-7), and formula (B1-B1-). 11) -Formula (B1-14), Formula (B1-17), Formula (B1-20) -Formula (B1-26), Formula (B1-29), Formula (B1-31) -Formula (B1-48) ) Is more preferable.

The acid generator (B) may contain one type alone or two or more types.
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。
ｍａ及びｎａは、それぞれ独立して、０又は１を表し、ｍａ及びｎａの少なくとも一方は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は、酸素原子又は硫黄原子を表す。
ｎａ’は、０又は１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.
ma and na independently represent 0 or 1, and at least one of ma and na represents 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 to which they are bonded, and the hydrocarbon group and the divalent complex. _{The −CH 2−} contained in the ring group may be replaced by −O− or −S−.
X represents an oxygen atom or a sulfur atom.
na'represents 0 or 1.
* 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、アダマンチルジメチル基、ノルボルニルエチル基等が挙げられる。
好ましくは、ｍａは０であり、ｎａは１である。
Ｒ^a1及びＲ^a2が互いに結合して２価の脂環式炭化水素基を形成する場合の−Ｃ（Ｒ^a1）（Ｒ^a2）（Ｒ^a3）としては、下記の基が挙げられる。２価の脂環式炭化水素基は、好ましくは炭素数３〜１２である。＊は−Ｏ−との結合手を表す。

^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 have preferably 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, an adamantyldimethyl group and a norbornyl group. Examples include an ethyl group.
Preferably, ma is 0 and na is 1.
^{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-.

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。
ｎａ’は、好ましくは０である。 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.
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, a p-adamantylphenyl group, a trill 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 a 2-methyl-6-ethylphenyl group.
When forming a divalent heterocyclic group formed together with the carbon atoms and X which R ^{a2 'and} R ^a3' are bonded to which they are attached to each ^{other, -C (R a1 ') (} R a3') -X-R The following groups can be mentioned as ^a2'. * Represents a bond.

Of R ^{a1 'and} R ^a2', it is preferable that at least one is a hydrogen atom.
na'is preferably 0.

Examples of the group represented by the formula (1), 1,1-dialkyl alkoxycarbonyl group (formula (1) R ^a1 to R ^a3 is alkyl group in a, ma = 0, na = 1, preferably 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 are adamantyl groups, R ^a3 is an alkyl group, ma = 0, na = 1 ) And 1- (adamantan-1-yl) -1- ^{alkylalkoxycarbonyl group (in formula (1), Ra1} and ^Ra2 are alkyl groups, ^Ra3 is adamantyl group, ma = 0, na = 1), etc. Further, the following groups can be mentioned. * Represents a bond.

Specific examples of the group 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.

［式（ａ１−０）、式（ａ１−１）及び式（ａ１−２）中、
Ｌ^a01、Ｌ^ａ１及びＬ^ａ２は、それぞれ独立に、−Ｏ−又は^＊−Ｏ−（ＣＨ_２）_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^a01、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^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。
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合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。］ The structural unit derived from the (meth) acrylic monomer having a group represented by the formula (1) is preferably a structural unit represented by the formula (a1-0) (hereinafter referred to as a structural unit (a1-0)). (In some cases), a structural unit represented by the formula (a1-1) (hereinafter, may be referred to as a structural unit (a1-1)) or a structural unit represented by the formula (a1-2) (hereinafter, referred to as a structural unit). It may be referred to as a structural unit (a1-2)). These may be used alone or in combination of two or more.

[In the formula (a1-0), the formula (a1-1) and the formula (a1-2),
L ^{a01, L a1} and ^{L a2} each independently, -O- or _{^{* -O- (CH 2) k1 -CO}} -O- the stands, k1 represents an integer of 1-7, and * Represents a bond with −CO−.
R ^a01 , R ^a4 and R ^a5 each independently represent 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.
R ^a6 and R ^a7 each 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. ]

R ^a01 , R ^a4 and R ^a5 are preferably methyl groups.
L ^{a01, L a1} and ^{L a2} are preferably oxygen atom or _{* -O- (CH 2) k01 -CO} -O- and is (however, k01 is preferably either 1 to 4 integer, more preferably Is 1.), More preferably an oxygen atom.
The alkyl groups of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 , the alicyclic hydrocarbon group and the group combining these are the same as the groups listed in ^{R a1 to} R ^{a3 of the formula (1).} The group is mentioned.
The alkyl groups of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 have preferably 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.
The alicyclic hydrocarbon groups of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 have preferably 3 to 8 carbon atoms, more preferably 3 to 6 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 of these alkyl groups and the alicyclic hydrocarbon group.
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.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, and more preferably 0 or 1.
n1'is preferably 0 or 1.

As the structural unit (a1-0), for example, the structural unit represented by any one of the formulas (a1-0-1) to (a1-0-12) and the methyl group corresponding to ^{R a01 are hydrogen atoms.} Examples of the structural units have been replaced, and structural units represented by any of the formulas (a1-0-1) to (a1-0-10) are preferable.

Examples of the monomer for deriving the structural unit (a1-1) include the monomers described in JP-A-2010-204646. Among them, preferred is formula (a1-1-1) ~ formula (a1-1-4) structural units in which a methyl group is replaced by a hydrogen atom corresponding to the structural units and ^{R a4} represented by any one of formula (a1 The structural unit represented by any of 1-1) to (a1-1-4) is more preferable.

The structural unit (a1-2), a methyl group corresponding to the structural units and ^{R a5} represented by any of formulas (a1-2-1) ~ formula (a1-2-6) is replaced by a hydrogen atom Structural units are mentioned, and the formula (a1-2-2), the formula (a1-2-5) and the formula (a1-2-6) are 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.

Further, examples of the structural unit (a1) having the group (1) include the following 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.

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 - represents, h3 represents an integer of 1 to 4, * represents a bond to 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. The 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.

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.

Examples of the structural unit (a2) having a phenolic hydroxy group include the structural units described below.

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 an integer of 1-7. * 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 γ-butyrolactone ring, an adamantane lactone ring, or a bridged ring containing 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、それぞれ独立に、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 a group represented by −O− or ^* −O− (CH ₂ ) _k3 −CO−O− (k3 represents an integer of any of 1 to 7). * 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 formula (a3-2),
^La5 represents a group represented by −O− or ^* −O− (CH ₂ ) _k3 −CO−O− (k3 represents an integer of any of 1 to 7). * 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 a group represented by −O− or ^* −O− (CH ₂ ) _k3 −CO−O− (k3 represents an integer of any of 1 to 7). * 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} independently represent an alkanediyl group having 1 to 6 carbon atoms.
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. ]

Examples of the aliphatic hydrocarbon groups of R ^a21 , R ^a22 , R ^a23 and R ^a25 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group and tert-butyl group. Alkyl groups 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、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 (a3-2-1) 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). 5 to 60 mol% is preferable, 5 to 50 mol% is more preferable, and 10 to 50 mol% is further preferable.

<Other structural units (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-desorbed hydrocarbon group are used. Examples thereof include structural units having a structure (hereinafter, may be referred to as “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 an 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 aliphatic saturated hydrocarbon group of 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 and a butane-1,4-diyl group. , Etc., 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, a propane-1, Examples thereof include branched alkanediyl groups such as 2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.

The perfluoroalkanediyl group of L ³ includes a difluoromethylene group, a perfluoroethylene group, a perfluoropropane-1,1-diyl 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 Examples thereof include -2,2-diyl group, perfluorooctane-3,3-diyl group, perfluorooctane-4,4-diyl group and the like.
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, 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。ただし、Ａ^ａ４１及びＲ^ａ４２のうち少なくとも１つは、置換基としてハロゲン原子（好ましくはフッ素原子）を有する。

〔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). However, ^{at least one of Aa41} and ^Ra42 has a halogen atom (preferably a fluorine atom) as a substituent.

[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 a polycyclic alicyclic hydrocarbon group 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。］ The aliphatic hydrocarbon group having a group represented by the formula (ag3) 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. Examples include aliphatic hydrocarbon groups. 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 .

Examples of the structural unit represented by the formula (a4-1) 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.

［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で置換されていてもよい。但し、Ｌ^５５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。
Ｌ^５５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 may be substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms. .. However, ^{the hydrogen atom bonded to the carbon atom at the bonding 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-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 ^{x 1} 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 ⁵¹ 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 consisting 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 3 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 by 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. As a salt that generates an acid having a weaker acidity than the acid generated from the acid generator (B) (hereinafter, may be referred to as “weak acid intramolecular salt (D)”), a salt represented by the following formula, In addition, the salts described in JP-A-2012-229206, JP-A-2012-6908, JP-A-2012-72109, JP-A-2011-39502 and JP-A-2011-191745 can be mentioned.

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

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. The exposure light source includes a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), an F ₂ excimer laser (wavelength 157 nm) that emits laser light in the ultraviolet region, and a solid-state laser light source (YAG or semiconductor laser). Etc.), and various ones such as those that radiate harmonic laser light in the far ultraviolet region or vacuum ultraviolet region by wavelength conversion, those that irradiate electron beams, super-ultraviolet light (EUV), etc. are used. 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 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−１−ａ）で表される化合物２部、ジメチルホルムアミド１０部、炭酸カリウム２．１部及びヨウ化カリウム０．６部を混合し、２３℃で３０分間攪拌し、さらに、５０℃で２時間撹拌した。得られた混合物に、式（Ｉ−１−ｂ）で表される化合物１１．７部を添加し、５０℃で１０時間撹拌した。得られた反応物を濃縮し、クロロホルム３０部及びイオン交換水１５部を加え、２３℃で３０分間攪拌した。その後、静置し、分液した。回収された有機層に、イオン交換水１５部を混合し、２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を５回行った。得られた有機層を濃縮することにより、式（Ｉ−１―ｃ）で表される化合物３．４部を得た。 Example 1: Synthesis of salt represented by formula (I-1)

2 parts of the compound represented by the formula (I-1-a), 10 parts of dimethylformamide, 2.1 parts of potassium carbonate and 0.6 parts of potassium iodide are mixed, stirred at 23 ° C. for 30 minutes, and further 50 parts. The mixture was stirred at ° C. for 2 hours. To the obtained mixture, 11.7 parts of the compound represented by the formula (I-1-b) was added, and the mixture was stirred at 50 ° C. for 10 hours. The obtained reaction product was concentrated, 30 parts of chloroform and 15 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it was allowed to stand and the liquid was separated. 15 parts of ion-exchanged water was mixed with the recovered organic layer, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. By concentrating the obtained organic layer, 3.4 parts of the compound represented by the formula (I-1-c) was obtained.

式（Ｉ−１−ｄ）で表される塩２部、アセトニトリル１０部及び式（Ｉ−１−ｅ）で表される化合物０．９部を混合し、２３℃で３０分間攪拌し、さらに、５０℃で２時間撹拌することにより、式（Ｉ−１−ｆ）で表される塩を含む溶液を得た。得られた式（Ｉ−１−ｆ）で表される塩を含む溶液に、式（Ｉ−１−ｃ）で表される化合物２．９部を添加し、５０℃で１０時間撹拌した後、濃縮した。得られた濃縮残渣に、クロロホルム４０部及びイオン交換水２０部を加え、２３℃で３０分間攪拌した。得られた混合物を、静置し、分液した。回収された有機層に、イオン交換水２０部を加え、２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を４回行った。得られた有機層を濃縮し、得られた濃縮物に、アセトニトリル１．５５部及びｔｅｒｔ−ブチルメチルエーテル４０部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ−１）で表される塩２．５部を得た。

2 parts of the salt represented by the formula (I-1-d), 10 parts of acetonitrile and 0.9 part of the compound represented by the formula (I-1-e) are mixed, stirred at 23 ° C. for 30 minutes, and further. , 50 ° C. for 2 hours to obtain a solution containing a salt represented by the formula (I-1-f). To the obtained solution containing the salt represented by the formula (I-1-f), 2.9 parts of the compound represented by the formula (I-1-c) was added, and the mixture was stirred at 50 ° C. for 10 hours. , Concentrated. To the obtained concentrated residue, 40 parts of chloroform and 20 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes. The resulting mixture was allowed to stand and separated. To the recovered organic layer, 20 parts of ion-exchanged water was added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. This washing operation was performed four times. The obtained organic layer was concentrated, 1.55 parts of acetonitrile and 40 parts of tert-butyl methyl ether were added to the obtained concentrate, and the mixture was stirred to remove the supernatant. The obtained residue was dissolved in acetonitrile and concentrated to obtain 2.5 parts of a salt represented by the formula (I-1).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 783.0

式（Ｉ−１１−ａ）で表される塩５部、ジメチルホルムアミド２０部、炭酸カリウム１．６部及びヨウ化カリウム０．５部を混合し、２３℃で３０分間攪拌し、さらに、５０℃で２時間撹拌した。得られた混合物に、式（Ｉ−１１−ｂ）で表される化合物１．８部を添加し、５０℃で１０時間撹拌した。得られた反応物を濃縮し、クロロホルム８０部及び５％シュウ酸水溶液８０部を加え、２３℃で３０分間攪拌した。得られた混合物を、静置し、分液した。回収された有機層に、イオン交換水４０部を加えて２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を８回行った。得られた有機層を濃縮し、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル４０部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ−１１―ｃ）で表される塩２．２部を得た。

式（Ｉ−１１―ｃ）で表される塩０．７部及びクロロホルム１０部を混合し、２３℃で３０分間攪拌した。得られた混合物に、ピリジン０．２８部を加え、４０℃に昇温した。得られた混合物に、さらに、式（Ｉ−１１―ｄ）で表される化合物０．７部及びクロロホルム１０部の混合溶液を１時間かけて滴下した。滴下後、４０℃で１８時間攪拌した後、２３℃まで冷却した。得られた反応溶液に、イオン交換水２０部を添加、攪拌し、分液により有機層を回収した。回収された有機層に、５℃の１０％炭酸カリウム水溶液２０部を添加して洗浄し、分液して有機層を回収した後、回収された有機層にさらに、イオン交換水２０部を添加して水洗し、分液を行って有機層を回収した。この水洗操作を３回繰り返して行った。回収された有機層を濃縮した後、得られた残渣をアセトニトリルに溶解し、濃縮した。その後、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル１０部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−１１）で表される塩０．５８部を得た。 Example 2: Synthesis of salt represented by formula (I-11)

5 parts of the salt represented by the formula (I-11-a), 20 parts of dimethylformamide, 1.6 parts of potassium carbonate and 0.5 part of potassium iodide are mixed, stirred at 23 ° C. for 30 minutes, and further 50 parts. The mixture was stirred at ° C. for 2 hours. To the obtained mixture, 1.8 parts of the compound represented by the formula (I-11-b) was added, and the mixture was stirred at 50 ° C. for 10 hours. The obtained reaction product was concentrated, 80 parts of chloroform and 80 parts of a 5% aqueous oxalic acid solution were added, and the mixture was stirred at 23 ° C. for 30 minutes. The resulting mixture was allowed to stand and separated. 40 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 recover the organic layer. This washing operation was performed 8 times. The obtained organic layer was concentrated, and 40 parts of tert-butyl methyl ether was added to the obtained concentrate and stirred to remove the supernatant. The obtained residue was dissolved in acetonitrile and concentrated to obtain 2.2 parts of a salt represented by the formula (I-11-c).

0.7 parts of the salt represented by the formula (I-11-c) and 10 parts of chloroform were mixed and stirred at 23 ° C. for 30 minutes. To the obtained mixture, 0.28 part of pyridine was added, and the temperature was raised to 40 ° C. Further, a mixed solution of 0.7 parts of the compound represented by the formula (I-11-d) and 10 parts of chloroform was added dropwise to the obtained mixture over 1 hour. After the dropping, the mixture was stirred at 40 ° C. for 18 hours and then cooled to 23 ° C. To the obtained reaction solution, 20 parts of ion-exchanged water was added and stirred, and the organic layer was recovered by liquid separation. 20 parts of a 10% potassium carbonate aqueous solution at 5 ° C. was added to the recovered organic layer for washing, and the liquid was separated to recover the organic layer, and then 20 parts of ion-exchanged water was further added to the recovered organic layer. Then, it was washed with water and separated to recover the organic layer. This washing operation was repeated 3 times. After concentrating the recovered organic layer, the obtained residue was dissolved in acetonitrile and concentrated. Then, 10 parts of tert-butyl methyl ether was added to the obtained concentrate and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 0.58 parts of a salt represented by the formula (I-11).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 640.9

式（Ｉ−１−ａ）で表される化合物２部、アセトニトリル２０部及び式（Ｉ−１−ｅ）で表される化合物４．８部を混合し、２３℃で３０分間攪拌し、さらに、５０℃で２時間撹拌した。得られた混合物に、式（Ｉ−１３−ｂ）で表される化合物１２．９部を添加し、５０℃で１０時間撹拌した。得られた反応物を濃縮し、クロロホルム４０部及びイオン交換水２０部を加え、２３℃で３０分間攪拌した。得られた混合物を、静置し、分液した。回収された有機層に、イオン交換水２０部を加えて２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を５回行った。得られた有機層を濃縮することにより、式（Ｉ−１３―ｄ）で表される化合物９．９部を得た。 Example 3: Synthesis of salt represented by formula (I-13)

Two parts of the compound represented by the formula (I-1-a), 20 parts of acetonitrile and 4.8 parts of the compound represented by the formula (I-1-e) are mixed, stirred at 23 ° C. for 30 minutes, and further. , Stirred at 50 ° C. for 2 hours. To the obtained mixture, 12.9 parts of the compound represented by the formula (I-13-b) was added, and the mixture was stirred at 50 ° C. for 10 hours. The obtained reaction product was concentrated, 40 parts of chloroform and 20 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes. The resulting mixture was allowed to stand and separated. To the recovered organic layer, 20 parts of ion-exchanged water was added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. This washing operation was performed 5 times. By concentrating the obtained organic layer, 9.9 parts of the compound represented by the formula (I-13-d) was obtained.

式（Ｉ−１−ｄ）で表される塩２部、アセトニトリル１０部及び式（Ｉ−１−ｅ）で表される化合物０．９部を混合し、２３℃で３０分間攪拌し、さらに、５０℃で２時間撹拌することにより、式（Ｉ−１３−ｇ）で表される塩を含む溶液を得た。得られた式（Ｉ−１３−ｇ）で表される塩を含む溶液に、式（Ｉ−１３−ｄ）で表される化合物４．４部を添加し、５０℃で１０時間撹拌した後、濃縮した。得られた濃縮残渣に、クロロホルム４０部及びイオン交換水２０部を加え、２３℃で３０分間攪拌した。得られた混合物を、静置し、分液した。回収された有機層に、イオン交換水２０部を仕込み、２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を４回行った。得られた有機層を濃縮し、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル４０部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ−１）で表される化合物４．４部を得た。

2 parts of the salt represented by the formula (I-1-d), 10 parts of acetonitrile and 0.9 part of the compound represented by the formula (I-1-e) are mixed, stirred at 23 ° C. for 30 minutes, and further. , 50 ° C. for 2 hours to obtain a solution containing a salt represented by the formula (I-13-g). 4.4 parts of the compound represented by the formula (I-13-d) was added to the obtained solution containing the salt represented by the formula (I-13-g), and the mixture was stirred at 50 ° C. for 10 hours. , Concentrated. To the obtained concentrated residue, 40 parts of chloroform and 20 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes. The resulting mixture was allowed to stand and separated. Twenty parts of ion-exchanged water was charged into the recovered organic layer, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed four times. The obtained organic layer was concentrated, and 40 parts of tert-butyl methyl ether was added to the obtained concentrate and stirred to remove the supernatant. The obtained residue was dissolved in acetonitrile and concentrated to obtain 4.4 parts of the compound represented by the formula (I-1).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 1118.9

式（Ｉ−１−ａ）で表される化合物５部、式（Ｉ−７−ｂ）で表される化合物１４．９２部及びクロロホルム４０部を混合し、２３℃で３０分間攪拌した。得られた混合物に、硫酸１．１０部を添加し、モレキュラーシーブ存在下、６０℃で１０時間還流撹拌した。得られた反応物を２３℃まで冷却した後、イオン交換水２０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液した。この水洗の操作を５回行った。得られた有機層を濃縮することにより、式（Ｉ−７―ｃ）で表される化合物４．９２部を得た。 Example 4: Synthesis of salt represented by formula (I-7)

5 parts of the compound represented by the formula (I-1-a), 14.92 parts of the compound represented by the formula (I-7-b) and 40 parts of chloroform were mixed and stirred at 23 ° C. for 30 minutes. To the obtained mixture, 1.10 parts of sulfuric acid was added, and the mixture was reflux-stirred at 60 ° C. for 10 hours in the presence of a molecular sieve. After cooling the obtained reaction product to 23 ° C., 20 parts of ion-exchanged water was added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it was allowed to stand and the liquid was separated. This washing operation was performed 5 times. By concentrating the obtained organic layer, 4.92 parts of the compound represented by the formula (I-7-c) was obtained.

式（Ｉ−１−ｄ）で表される塩１．３８部、クロロホルム１４部及び式（Ｉ−１−ｅ）で表される化合物０．６１部を混合し、２３℃で３０分間攪拌し、さらに、５０℃で２時間撹拌することにより、式（Ｉ−１−ｆ）で表される塩を含む溶液を得た。得られた式（Ｉ−１−ｆ）で表される塩を含む溶液に、式（Ｉ−７−ｃ）で表される化合物１．５７部を添加し、５０℃で１０時間撹拌した後、濃縮した。得られた濃縮残渣に、クロロホルム３０部及びイオン交換水２０部を加え、２３℃で３０分間攪拌した。得られた混合物を、静置し、分液した。回収された有機層に、イオン交換水２０部を加え、２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を４回行った。得られた有機層を濃縮し、得られた濃縮物に、アセトニトリル１部及びｔｅｒｔ−ブチルメチルエーテル２０部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ−７）で表される塩１．８９部を得た。

1.38 parts of the salt represented by the formula (I-1-d), 14 parts of chloroform and 0.61 part of the compound represented by the formula (I-1-e) are mixed and stirred at 23 ° C. for 30 minutes. Further, the mixture was further stirred at 50 ° C. for 2 hours to obtain a solution containing a salt represented by the formula (I-1-f). To the obtained solution containing the salt represented by the formula (I-1-f), 1.57 parts of the compound represented by the formula (I-7-c) was added, and the mixture was stirred at 50 ° C. for 10 hours. , Concentrated. To the obtained concentrated residue, 30 parts of chloroform and 20 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes. The resulting mixture was allowed to stand and separated. To the recovered organic layer, 20 parts of ion-exchanged water was added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. This washing operation was performed four times. The obtained organic layer was concentrated, and 1 part of acetonitrile and 20 parts of tert-butyl methyl ether were added to the obtained concentrate and stirred, and the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 1.89 parts of a salt represented by the formula (I-7).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 655.0

式（Ｉ−１−ｃ）で表される化合物０．３１部、クロロホルム１０部及び式（Ｉ−１６２−ａ）で表される塩０．３５部を混合し、２３℃で３０分間攪拌し、さらに、５０℃で２時間撹拌した後、濃縮した。得られた濃縮残渣に、クロロホルム４０部及びイオン交換水２０部を加え、２３℃で３０分間攪拌した。得られた混合物を、静置し、分液した。回収された有機層に、イオン交換水２０部を加え、２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を４回行った。得られた有機層を濃縮し、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル１０部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ−１６２）で表される塩０．４８部を得た。 Example 5: Synthesis of salt represented by formula (I-162)

0.31 part of the compound represented by the formula (I-1-c), 10 parts of chloroform and 0.35 part of the salt represented by the formula (I-162-a) were mixed and stirred at 23 ° C. for 30 minutes. Further, the mixture was further stirred at 50 ° C. for 2 hours and then concentrated. To the obtained concentrated residue, 40 parts of chloroform and 20 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes. The resulting mixture was allowed to stand and separated. To the recovered organic layer, 20 parts of ion-exchanged water was added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. This washing operation was performed four times. The obtained organic layer was concentrated, and 10 parts of tert-butyl methyl ether was added to the obtained concentrate and stirred to remove the supernatant. The obtained residue was dissolved in acetonitrile and concentrated to obtain 0.48 parts of a salt represented by the formula (I-162).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 991.1.

式（Ｉ−１−ｃ）で表される化合物０．３１部、クロロホルム１０部及び式（Ｉ−１８６−ａ）で表される塩０．３４部を混合し、２３℃で３０分間攪拌し、さらに、５０℃で２時間撹拌した後、濃縮した。得られた濃縮残渣に、クロロホルム４０部及びイオン交換水２０部を加え、２３℃で３０分間攪拌した。得られた混合物を、静置し、分液した。回収された有機層に、イオン交換水２０部を加え、２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を４回行った。得られた有機層を濃縮し、得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル１０部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ−１８６）で表される塩０．４４部を得た。 Example 6: Synthesis of salt represented by formula (I-186)

0.31 part of the compound represented by the formula (I-1-c), 10 parts of chloroform and 0.34 part of the salt represented by the formula (I-186-a) were mixed and stirred at 23 ° C. for 30 minutes. Further, the mixture was further stirred at 50 ° C. for 2 hours and then concentrated. To the obtained concentrated residue, 40 parts of chloroform and 20 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes. The resulting mixture was allowed to stand and separated. To the recovered organic layer, 20 parts of ion-exchanged water was added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to recover the organic layer. This washing operation was performed four times. The obtained organic layer was concentrated, and 10 parts of tert-butyl methyl ether was added to the obtained concentrate and stirred to remove the supernatant. The obtained residue was dissolved in acetonitrile and concentrated to obtain 0.44 parts of a salt represented by the formula (I-186).

MS (ESI (+) Spectrum): M ⁺ 237.1
MS (ESI (-) Spectrum): M ^- 991.1.

Synthesis of Resin The compounds (monomers) used for 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 reprecipitation operation of filtering the resin is performed twice, and the weight average is obtained. 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 the monomers, and these were added at 75 ° C. It was heated for about 5 hours. 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 was dissolved in dioxane again, and the obtained solution was poured into a methanol / water mixed solvent to precipitate the resin, and the reprecipitation operation of filtering the resin was performed twice, and the weight average molecular weight was 1.7. the resin X1 of × 10 ⁴ was obtained in 77% yield. This resin X1 has the following structural units.

Synthesis Example 3: Synthesis of Resin X2 A monomer (a5-1-1) and a 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 2, 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.

＜クエンチャー（Ｃ）＞
Ｄ１：（東京化成工業（株）製）

＜溶剤＞
プロピレングリコールモノメチルエーテルアセテート ２６５部
プロピレングリコールモノメチルエーテル ２０部
２−ヘプタノン ２０部
γ−ブチロラクトン ３．５部 <Resin>
A1, X1, X2: Resin A1, Resin X1, Resin X2
<Acid generator>
I-1: Salt represented by the formula (I-1) I-7: Salt represented by the formula (I-7) I-11: Salt represented by the formula (I-11) I-13: Formula Salt represented by (I-13) I-162: Salt represented by formula (I-162) I-186: Salt represented by formula (I-186) B1-5: Salt represented by formula (B1-5) Salt represented by (Synthesized according to Examples of JP-A-2015-200886)
B1-21: Salt represented by the formula (B1-21) (synthesized according to Examples of JP-A-2015-200886)
B1-22: Salt represented by the formula (B1-22) (synthesized according to Examples of JP-A-2015-200886)
B1-X: Synthesized according to the examples of JP2012-229199

<Quencher (C)>
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 Industries, 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 2 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 polarization). / 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 2 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 at which the hole diameter formed by using the mask was 45 nm was defined as the effective sensitivity.

<Mask error factor (MEF) evaluation>
In terms of effective sensitivity, a resist pattern was formed using masks having mask hole diameters (hole diameters of translucent portions of the mask) of 57 nm, 56 nm, 55 nm, 54 nm, and 53 nm (hole pitches are all 90 nm), respectively. The slope of the regression line when the hole diameter of the resist pattern formed (transferred) on the substrate by exposure was plotted on the vertical axis with the mask hole diameter on the horizontal axis was calculated as the MEF value.
Those with a MEF value of 5.0 or less are evaluated as having a good MEF, and are marked with ○.
Those having a MEF value of more than 5.0 were evaluated as having poor MEF and were evaluated as x.
The results are shown in Table 3. The numbers in parentheses indicate the MEF value.

The resist composition of the present invention is suitable for microfabrication of semiconductors because a resist pattern can be produced with a good mask error factor (MEF).

Claims (6)

An acid generator containing a salt represented by the formula (I).

[In formula (I),
Q ^A1 and Q ^A2 independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
L ^b1 of the formula (L ¹ -1), a group represented by the formula (L ¹ -2) or formula (L ¹ -3).
R ¹ represents a hydrogen atom, a fluorine atom or a hydroxy group.
m represents any integer from 0 to 2, n represents any integer from 1 to 12, and o represents 0 or 1.
nn represents 2. The plurality of R ¹ , m, n, and o that exist may be different or the same.
Z1 ⁺ represents an organic counterion. ]

Wherein (L ¹ -1), formula (L ¹ -2) and formula (L ¹ -3),
X ⁰ represents a divalent aliphatic hydrocarbon group having 1 to 14 carbon atoms which may have a single bond and a fluorine atom or a group represented by the formula (a-1).

(In equation (a-1),
s represents 0 or 1.
X ¹⁰ and X ¹¹ are the same or different and represent an oxygen atom, a carbonyl group, a carbonyloxy group, an oxycarbonyl group or an oxycarbonyloxy group.
A ¹⁰ and A ¹¹ each independently represent a divalent aliphatic hydrocarbon group having 1 to 12 carbon atoms which may have a fluorine atom.
A ¹² represents a divalent aliphatic hydrocarbon group having 1 to 12 carbon atoms which may have a single bond or a fluorine atom.
* Represents a bond with W or a carbon atom. )
W represents a carbon atom or an alicyclic hydrocarbon group having 4 to 18 carbon atoms.
X ¹ represents -O- * 1, -O-CO- * 1, -O-CH _2- * 1 or -O-CH _2- CO-O- * 1. * 1 represents a bond with − (CH ₂ ) _m − (CF ₂ ) _n − (CH ₂ ) _O −R ^1.
X ² represents -O- * 2, -O-CO- * 2, -O-CH _2- * 2, or -O-CH _2- CO-O- * 2. * 2 represents a bond with − (CH ₂ ) _m − (CF ₂ ) _n − (CH ₂ ) _O −R ^1.
X ³ represents -O- * 1 or -O-CH _2- CO-O- * 1. * 1 represents a bond with − (CH ₂ ) _m − (CF ₂ ) _n − (CH ₂ ) _O −R ^1.
X ⁴ represents -O- * 2 or -O-CH _2- CO-O- * 2. * 2 represents a bond with − (CH ₂ ) _m − (CF ₂ ) _n − (CH ₂ ) _O −R ^1.
X ⁵ represents -O- * 1, -O-CO- * 1 or -O-CH _2- * 1. * 1 represents a bond with − (CH ₂ ) _m − (CF ₂ ) _n − (CH ₂ ) _O −R ^1.
X ⁶ represents -O- * 2, -O-CO- * 2 or -O-CH _2- * 2. * 2 represents a bond with − (CH ₂ ) _m − (CF ₂ ) _n − (CH ₂ ) _O −R ^1.
* L0 represents a bond with -C (Q ^A1 ) (Q ^A2)-.
m1, m2, m3, m4 and m5 each independently represent an integer of 0 to 6.
R ^L represents a hydrogen atom or an aliphatic hydrocarbon group of carbon atoms which may 1 to 14 have a fluorine atom.
* L1 and * L2 represent a bond _{with-(CH 2} ) m- (CF ₂ ) n- (CH ₂ ) o-R ^1.
However, when the W is an alicyclic hydrocarbon group, − (CH ₂ ) _m1 − and − (CH ₂ ) _m2 −, − (CH ₂ ) _m4 − and − (CH ₂ ) _m5 − are respectively. Not bonded to the same carbon atom of W. ] The acid generator according to ^{claim 1} , wherein L ^b1 is a group represented by the formula (L 1-2). A resist composition containing the acid generator according to claim 1 or 2 and a resin containing a structural unit having an acid unstable group. The resist composition according to claim 3 , further comprising a resin containing a structural unit having a fluorine atom. The resist composition according to claim 3 or 4 , 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 any one of claims 3 to 5 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.