JP7284658B2 - RESIST COMPOSITION AND RESIST PATTERN MANUFACTURING METHOD - Google Patents

Description

The present invention relates to a resin, a resist composition, a resist pattern manufacturing method using the resist composition, and the like.

特許文献２には、下記構造単位を有する樹脂を含有するレジスト組成物も記載されている。

Patent Document 1 describes a resist composition containing a resin having the following structural unit.

Patent Document 2 also describes a resist composition containing a resin having the following structural unit.

JP 2012-098520 A WO2017/002737

The present invention provides a resin that forms a resist pattern with better CD uniformity (CDU) than a resist pattern formed by a resist composition containing the above resin.

［式（Ｉ）中、
Ｒ^１は、水素原子又はメチル基を表す。
Ｒ^２、Ｒ^３及びＲ^４は、それぞれ独立に、炭素数１～４のアルキル基を表す。
Ｒ^５は、炭素数１～８のアルキル基を表す。
ｍは、０～８のいずれかの整数を表す。
ｎは、０～３のいずれかの整数を表す。］

［式（ａ１－１）中、
Ｌ^a1は、－Ｏ－又は＊－Ｏ－（ＣＨ_２）_k1－ＣＯ－Ｏ－を表し、ｋ１は１～７の整数を表し、＊は－ＣＯ－との結合手を表す。
Ｒ^a4は、水素原子又はメチル基を表す。
Ｒ^a6は、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た基を表す。
ｍ１は、０～１４のいずれかの整数を表す。］

［式（ａ２－Ａ）中、
Ｒ^a50は、水素原子、ハロゲン原子又はハロゲン原子を有していてもよい炭素数１～６のアルキル基を表す。
Ｒ^a51は、ハロゲン原子、ヒドロキシ基、炭素数１～６のアルキル基、炭素数１～６のアルコキシ基、炭素数２～４のアルキルカルボニル基、炭素数２～４のアルキルカルボニルオキシ基、アクリロイルオキシ基又はメタクリロイルオキシ基を表す。
Ａ^a50は、単結合又は^＊－Ｘ^a51－（Ａ^a52－Ｘ^a52）_nｂ－を表し、＊は－Ｒ^a50が結合する炭素原子との結合部位を表す。
Ａ^a52は、炭素数１～６のアルカンジイル基を表す。
Ｘ^a51及びＸ^a52は、それぞれ独立に、－Ｏ－、－ＣＯ－Ｏ－又は－Ｏ－ＣＯ－を表す。
ｎｂは、０又は１を表す。
ｍｂは０～４のいずれかの整数を表す。ｍｂが２以上のいずれかの整数である場合、複数のＲ^a51は互いに同一であっても異なってもよい。］
［２］さらに、式（ａ１－２）で表される構造単位を含む［１］記載の樹脂。

［式（ａ１－２）中、
Ｌ^a2は、－Ｏ－又は＊－Ｏ－（ＣＨ_２）_ｋ１－ＣＯ－Ｏ－を表し、ｋ１は１～７の整数を表し、＊は－ＣＯ－との結合手を表す。
Ｒ^a5は、水素原子又はメチル基を表す。
Ｒ^a7は、炭素数１～３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た基を表す。
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。］
［３］［１］又は［２］記載の樹脂と、酸発生剤とを含むレジスト組成物。
［４］酸発生剤が、式（Ｂ１）で表される塩を含む［３］記載のレジスト組成物。

［式（Ｂ１）中、
Ｑ^b1及びＱ^b2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１～２４の２価の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる－ＣＨ_２－は、－Ｏ－又は－ＣＯ－に置き換わっていてもよく、該２価の飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基で置換されていてもよい。
Ｙは、置換基を有していてもよいメチル基又は置換基を有していてもよい炭素数３～１８の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれる－ＣＨ_２－は、－Ｏ－、－Ｓ（Ｏ）_２－又は－ＣＯ－に置き換わっていてもよい。
Ｚ^＋は、有機カチオンを表す。］
［５］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［３］又は［４］記載のレジスト組成物。
［６］（１）［３］～［５］のいずれかに記載のレジスト組成物を基板上に塗布する工程、
（２）塗布後の組成物を乾燥させて組成物層を形成する工程、
（３）組成物層に露光する工程、
（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 resin containing a structural unit represented by formula (I), a structural unit represented by formula (a1-1) and a structural unit represented by formula (a2-A).

[in the formula (I),
R ¹ represents a hydrogen atom or a methyl group.
R ² , R ³ and R ⁴ each independently represent an alkyl group having 1 to 4 carbon atoms.
R ⁵ represents an alkyl group having 1 to 8 carbon atoms.
m represents any integer from 0 to 8;
n represents an integer of 0 to 3; ]

[In the formula (a1-1),
L ^a1 represents -O- or *-O-(CH ₂ ) _k1 -CO-O-, k1 represents an integer of 1 to 7, and * represents a bond with -CO-.
R ^a4 represents a hydrogen atom or a methyl group.
R ^a6 represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
m1 represents any integer from 0 to 14; ]

[In the formula (a2-A),
R ^a50 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a51 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl It represents an oxy group or a methacryloyloxy group.
A ^a50 represents a single bond or ^* -X ^a51 -(A ^a52 -X ^a52 ) _nb -, and * represents a bonding site with the carbon atom to which -R ^a50 bonds.
A ^a52 represents an alkanediyl group having 1 to 6 carbon atoms.
X ^a51 and X ^a52 each independently represent -O-, -CO-O- or -O-CO-.
nb represents 0 or 1;
mb represents an integer from 0 to 4; When mb is any integer of 2 or more, multiple R ^a51 may be the same or different. ]
[2] The resin according to [1], further comprising a structural unit represented by formula (a1-2).

[In formula (a1-2),
L ^a2 represents -O- or *-O-(CH ₂ ) _k1 -CO-O-, k1 represents an integer of 1 to 7, and * represents a bond with -CO-.
R ^a5 represents a hydrogen atom or a methyl group.
R ^a7 represents an alkyl group having 1 to 3 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
n1 represents any integer from 0 to 10;
n1' represents an integer of 0 to 3; ]
[3] A resist composition comprising the resin according to [1] or [2] and an acid generator.
[4] The resist composition according to [3], wherein the acid generator contains a salt represented by formula (B1).

[In formula (B1),
Q ^b1 and Q ^b2 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced with —O— or —CO— , a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Y represents an optionally substituted methyl group or an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, included in the alicyclic hydrocarbon group- CH ₂ - may be replaced by -O-, -S(O) ₂ - or -CO-.
Z ⁺ represents an organic cation. ]
[5] The resist composition according to [3] or [4], further comprising a salt that generates an acid weaker in acidity than the acid generated from the acid generator.
[6] (1) a step of applying the resist composition according to any one of [3] to [5] onto a substrate;
(2) a step of drying the applied composition to form a composition layer;
(3) exposing the composition layer;
(4) A process of heating the composition layer after exposure, and (5) a process of developing the composition layer after heating.

A resist pattern with good CD uniformity (CDU) can be produced by using a resist composition containing the resin of the present invention.

In this specification, unless otherwise specified, "(meth)acrylate" means "at least one selected from the group consisting of acrylate and methacrylate". Notations such as "(meth)acrylic acid" and "(meth)acryloyl" have the same meaning. Where structural units having "CH ₂ =C(CH ₃ )-CO-" or "CH ₂ =CH-CO-" are exemplified, structural units having both groups are similarly exemplified. shall be A "combined group" means a group in which two or more of the exemplified groups are combined by appropriately changing their valences. In addition, when stereoisomers exist, all stereoisomers are included.
As used herein, "the solid content of the resist composition" means the total amount of components excluding the solvent (E) described below from the total amount of the resist composition.

〔resin〕
The resin of the present invention comprises a structural unit represented by formula (I) (hereinafter sometimes referred to as structural unit (I)) and a structural unit represented by formula (a1-1) (hereinafter, structural unit ( a1-1)) and a structural unit represented by formula (a2-A) (hereinafter sometimes referred to as structural unit (a2-A)) (hereinafter referred to as “resin (A )”.

<Structural unit (I)>
In formula (I), R ¹ is preferably a methyl group.
Examples of alkyl groups for R ² , R ³ and R ⁴ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and tert-butyl group, preferably methyl group, It is an ethyl group or a tert-butyl group, more preferably two of R ² , R ³ and R ⁴ are a methyl group or an ethyl group and the rest are a methyl group, an ethyl group or a tert-butyl group.
The alkyl group for R ⁵ includes a methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group and the like, preferably an alkyl group having 1 to 4 carbon atoms, A straight-chain alkyl group having 1 to 4 carbon atoms is more preferred.
m is preferably an integer from 0 to 3, more preferably 0 or 1.
n is preferably 0 or 1, more preferably 0.

Structural units (I) include structural units described below.

In the structural units represented by formulas (I-1) to (I-24), structural units in which the methyl group corresponding to R ¹ is replaced with a hydrogen atom can also be cited as specific examples of structural unit (I). can. Among them, structural units represented by formulas (I-1) to (I-6) and formulas (I-13) to (I-20) are preferable, and formulas (I-1) to (I- 6), formula (I-19), more preferably structural units represented by formula (I-20), formula (I-1) to formula (I-3), formula (I-19), formula (I -20) is more preferred.

The content of the structural unit (I) in the resin (A) is preferably 3 to 80 mol%, more preferably 5 to 60 mol%, still more preferably 5 to 50 mol%, based on the total structural units. mol %, more preferably 5 to 45 mol %.

［式（ａ１－１）中、
Ｌ^a1は、－Ｏ－又は＊－Ｏ－（ＣＨ_２）_k1－ＣＯ－Ｏ－を表し、ｋ１は１～７の整数を表し、＊は－ＣＯ－との結合手を表す。
Ｒ^a4は、水素原子又はメチル基を表す。
Ｒ^a6は、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た基を表す。
ｍ１は、０～１４のいずれかの整数を表す。］ <Structural unit (a1-1)>
Structural unit (a1-1) is represented by the following formula.

[In the formula (a1-1),
L ^a1 represents -O- or *-O-(CH ₂ ) _k1 -CO-O-, k1 represents an integer of 1 to 7, and * represents a bond with -CO-.
R ^a4 represents a hydrogen atom or a methyl group.
R ^a6 represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
m1 represents any integer from 0 to 14; ]

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。
アルキル基と脂環式炭化水素基とを組合せた基は、これらアルキル基と脂環式炭化水素基とを組合せた合計炭素数が、１８以下であることが好ましい。
Ｒ^a6は、好ましくは炭素数１～６のアルキル基であり、より好ましくはメチル基、エチル基又はイソプロピル基であり、さらに好ましくはエチル基又はイソプロピル基である。
ｍ１は、好ましくは０～３のいずれかの整数であり、より好ましくは０又は１である。 R ^a4 is preferably a methyl group.
L ^a1 is preferably an oxygen atom or *—O—(CH ₂ ) _k01 —CO—O— (provided that k01 is preferably any integer of 1 to 4, more preferably 1). , and more preferably an oxygen atom.
Examples of the alkyl group for R ^a6 include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group and octyl group.
The alicyclic hydrocarbon group for R ^a6 may be either monocyclic or polycyclic. The monocyclic alicyclic hydrocarbon group includes cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group. Examples of polycyclic alicyclic hydrocarbon groups include decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* represents a bond). The alicyclic hydrocarbon group of R ^a6 preferably has 3 to 16 carbon atoms.

Groups in which an alkyl group and an alicyclic hydrocarbon group are combined include, for example, methylcyclohexyl group, dimethylcyclohexyl group, methylnorbornyl group, cyclohexylmethyl group, adamantylmethyl group, adamantyldimethyl group, norbornyl An ethyl group etc. are mentioned.
It is preferable that the combined group of an alkyl group and an alicyclic hydrocarbon group have a total carbon number of 18 or less.
R ^a6 is preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group or an isopropyl group, still more preferably an ethyl group or an isopropyl group.
m1 is preferably an integer from 0 to 3, more preferably 0 or 1.

Examples of structural units (a1-1) include structural units derived from monomers described in JP-A-2010-204646. Among them, a structural unit represented by any one of formulas (a1-1-1) to (a1-1-4) and a methyl group corresponding to R ^a4 in structural unit (a1-1) is replaced with a hydrogen atom. Structural units are preferred, and structural units represented by any one of formulas (a1-1-1) to (a1-1-4) are more preferred.

The content of the structural unit (a1-1) in the resin (A) is preferably 5 to 60 mol%, more preferably 5 to 50 mol%, still more preferably 10, based on the total structural units. ~40 mol%, and even more preferably 10 to 35 mol%.

［式（ａ２－Ａ）中、
Ｒ^a50は、水素原子、ハロゲン原子又はハロゲン原子を有してもよい炭素数１～６のアルキル基を表す。
Ｒ^a51は、ハロゲン原子、ヒドロキシ基、炭素数１～６のアルキル基、炭素数１～６のアルコキシ基、炭素数２～４のアルキルカルボニル基、炭素数２～４のアルキルカルボニルオキシ基、アクリロイルオキシ基又はメタクリロイルオキシ基を表す。
Ａ^a50は、単結合又は＊－Ｘ^a51－（Ａ^a52－Ｘ^a52）_nｂ－を表し、＊は－Ｒ^a50が結合する炭素原子との結合手を表す。
Ａ^a52は、炭素数１～６のアルカンジイル基を表す。
Ｘ^a51及びＸ^a52は、それぞれ独立に、－Ｏ－、－ＣＯ－Ｏ－又は－Ｏ－ＣＯ－を表す。
ｎｂは、０又は１を表す。
ｍｂは０～４のいずれかの整数を表す。ｍｂが２以上のいずれかの整数である場合、複数のＲ^a51は互いに同一であっても異なってもよい。］ <Structural unit (a2-A)>
The structural unit (a2-A) is represented by the following formula.

[In the formula (a2-A),
R ^a50 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a51 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl It represents an oxy group or a methacryloyloxy group.
A ^a50 represents a single bond or *—X ^a51 —(A ^a52 —X ^a52 ) _nb —, and * represents a bond with the carbon atom to which —R ^a50 bonds.
A ^a52 represents an alkanediyl group having 1 to 6 carbon atoms.
X ^a51 and X ^a52 each independently represent -O-, -CO-O- or -O-CO-.
nb represents 0 or 1;
mb represents an integer from 0 to 4; When mb is any integer of 2 or more, multiple R ^a51 may be the same or different. ]

Halogen atoms in R ^a50 include fluorine, chlorine and bromine atoms.
Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom for R ^a50 include trifluoromethyl group, difluoromethyl group, methyl group, perfluoroethyl group, 2,2,2-trifluoroethyl group, 1 , 1,2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3 , 3,4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group and perfluorohexyl groups.
R ^a50 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, even more preferably a hydrogen atom or a methyl group.
Examples of alkyl groups for R ^a51 include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl and hexyl groups.
Alkoxy groups for R ^a51 include methoxy, ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy and tert-butoxy groups. An alkoxy group having 1 to 4 carbon atoms is preferred, a methoxy group or an ethoxy group is more preferred, and a methoxy group is even more preferred.
The alkylcarbonyl group for R ^a51 includes an acetyl group, a propionyl group and a butyryl group.
The alkylcarbonyloxy group for R ^a51 includes an acetyloxy group, a propionyloxy group and a butyryloxy group.
R ^a51 is preferably a methyl group.
*-X ^a51 -(A ^a52 -X ^a52 ) _nb - includes *-O-, *-CO-O-, *-O-CO-, *-CO-O-A ^a52 -CO-O-, *-O-CO-A ^a52 -O-, *-O-A ^a52 -CO-O-, *-CO-O-A ^a52 -O-CO-, *-O-CO-A ^a52 -O-CO -, are included. Among them, *-CO-O-, *-CO-OA ^a52 -CO-O- or *-OA ^a52 -CO-O- is preferred.
The alkanediyl group includes methylene, ethylene, propane-1,3-diyl, propane-1,2-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane- 1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group and 2 -methylbutane-1,4-diyl group and the like.
A ^a52 is preferably a methylene group or an ethylene group.
A ^a50 is preferably a single bond, *—CO—O— or *—CO—O—A ^a52 —CO—O—, a single bond, *—CO—O— or *—CO—O—CH ₂ --CO--O-- is more preferred, and a single bond or *--CO--O-- is even more preferred.
mb is preferably 0, 1 or 2, more preferably 0 or 1, and particularly preferably 0.
The hydroxy group is preferably bonded to the o-position or p-position of the benzene ring, more preferably bonded to the p-position.

Examples of the structural unit (a2-A) include structural units derived from monomers described in JP-A-2010-204634 and JP-A-2012-12577.
The structural unit (a2-A) includes structural units represented by formulas (a2-2-1) to (a2-2-6) and formulas (a2-2-1) to (a2-2- Examples of the structural unit represented by 6) include a structural unit in which the methyl group corresponding to R ^a50 in the structural unit (a2-A) is replaced with a hydrogen atom. Structural unit (a2-A) includes a structural unit represented by formula (a2-2-1), a structural unit represented by formula (a2-2-3), and a structural unit represented by formula (a2-2-6). and the structural unit represented by formula (a2-2-1), the structural unit represented by formula (a2-2-3) or the structural unit represented by formula (a2-2-6), A structural unit in which the methyl group corresponding to R ^a50 in the structural unit (a2-A) is replaced with a hydrogen atom is preferred.

The content of the structural unit (a2-A) in the resin (A) is preferably 5 to 80 mol%, more preferably 10 to 70 mol%, still more preferably 10, based on the total structural units. ~65 mol%, still more preferably 10 to 55 mol%, even more preferably 10 to 50 mol%.
The structural unit (a2-A) can be included in the resin (A), for example, by polymerizing the structural unit (a1-4) described later and then treating with an acid such as p-toluenesulfonic acid. . Further, the structural unit (a2-A) can be included in the resin (A) by polymerizing with acetoxystyrene or the like and then treating with an alkali such as tetramethylammonium hydroxide.

The resin (A) of the present invention may be a polymer containing one or more structural units other than structural unit (I), structural unit (a1-1) and structural unit (a2-A). Structural units other than structural unit (I), structural unit (a1-1) and structural unit (a2-A) include structures having an acid labile group other than structural unit (I) and structural unit (a1-1) unit (hereinafter sometimes referred to as "structural unit (a1)"), a structural unit other than a structural unit having an acid-labile group and having a halogen atom (hereinafter sometimes referred to as "structural unit (a4)") ), a structural unit having no acid labile group other than the structural unit (a2-A) (hereinafter sometimes referred to as “structural unit (s)”), a structural unit having a non-eliminating hydrocarbon group (hereinafter “structural unit unit (a5)") and the like. Here, the acid-labile group means a group which has a leaving group, and upon contact with an acid, the leaving group leaves to form a hydrophilic group (for example, a hydroxy group or a carboxy group). In particular, the resin (A) preferably has a structural unit containing an acid-labile group in addition to the structural unit (I), the structural unit (a1-1), and the structural unit (a2-A). It is more preferable to have the unit (a1-2).
When the resin (A) contains structural units represented by formulas (a4) and/or (a5) described later (hereinafter sometimes referred to as "resin (AX)"), the structure in the resin (AX) of the present invention The content of unit (I) is preferably 5 to 75 mol%, more preferably 10 to 70 mol%, still more preferably It is 10 to 65 mol %, particularly preferably 10 to 60 mol %.

［式（１）中、Ｒ^a1、Ｒ^a２及び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の複素環基を形成し、該炭化水素基及び該複素環基に含まれる－ＣＨ_２－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-labile group (hereinafter sometimes referred to as "monomer (a1)").
The acid-labile group contained in the resin (A) is a group represented by formula (1) (hereinafter also referred to as group (1)) and/or a group represented by formula (2) (hereinafter referred to as group (2 )) is preferable.

[In formula (1), R ^a1 , R ^a2 and R ^a3 each 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 Alternatively, R ^a1 and R ^a2 are bonded to each other to form an alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atoms to which they are bonded.
ma and na each independently represent 0 or 1, and at least one of ma and na represents 1;
* represents a bond. ]

[In formula (2), R ^a1′ and R ^a2′ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^a3′ represents a hydrocarbon group having 1 to 20 carbon atoms. or R ^a2′ and R ^a3′ are bonded to each other to form a heterocyclic group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded and X, and the hydrocarbon group and the heterocyclic group include— CH ₂ - 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。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 alkyl groups for R ^a1 , R ^a2 and R ^a3 include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group and octyl group.
The alicyclic hydrocarbon groups for R ^a1 , R ^a2 and R ^a3 may be either monocyclic or polycyclic. The monocyclic alicyclic hydrocarbon group includes cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group. Examples of polycyclic alicyclic hydrocarbon groups include decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* represents a bond). The alicyclic hydrocarbon groups of R ^a1 , R ^a2 and R ^a3 preferably have 3 to 16 carbon atoms.

Groups in which an alkyl group and an alicyclic hydrocarbon group are combined include, for example, methylcyclohexyl group, dimethylcyclohexyl group, methylnorbornyl group, cyclohexylmethyl group, adamantylmethyl group, adamantyldimethyl group, norbornyl An ethyl group etc. are mentioned.
Preferably, ma is 0 and na is 1.
Examples of —C(R ^a1 )(R ^a2 )(R ^a3 ) when R ^a1 and R ^a2 combine to form an alicyclic hydrocarbon group include the following groups. The alicyclic hydrocarbon group preferably has 3-12 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 hydrocarbon groups for R ^a1′ , R ^a2′ and R ^a3′ include alkyl groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups and groups formed by combining these groups.
Alkyl groups and alicyclic hydrocarbon groups include the same groups as those listed for R ^a1 , R ^a2 and R ^a3 .
Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, naphthyl group, anthryl group, biphenyl group and phenanthryl group.
Examples of the combined group include a group obtained by combining the above-described alkyl group and an alicyclic hydrocarbon group (for example, a cycloalkylalkyl group), an aralkyl group (such as a benzyl group), and an aromatic hydrocarbon group having an alkyl group (p- methylphenyl group, p-tert-butylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.), alicyclic hydrocarbon group aromatic hydrocarbon groups (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.), aryl-cycloalkyl groups (phenylcyclohexyl group, etc.), and the like.
When R ^a2' and R ^a3' are bonded to each other to form a heterocyclic ring together with the carbon atom to which they are bonded and X, -C(R ^a1' )(R ^a3' )-X-R ^a2' group. * represents a bond.

At least one of R ^a1′ and R ^a2′ is preferably a hydrogen atom.
na' is preferably zero.

Group (1) includes the following groups.
A group of formula (1) wherein R ^a1 , R ^a2 and R ^a3 are alkyl groups, ma=0 and na=1. The group is preferably a tert-butoxycarbonyl group.
In formula (1), R ^a1 and R ^a2 form an adamantyl group together with the carbon atoms to which they are attached, R ^a3 is an alkyl group, ma = 0 and na = 1. .
A group in which R ^a1 and R ^a2 are each independently an alkyl group, R ^a3 is an adamantyl group, ma=0 and na=1 in formula (1).
Specific examples of the group (1) include the following groups. * represents a bond.

Specific examples of group (2) include the following groups. * represents a bond.

Monomer (a1) is preferably a monomer having an acid labile group and an ethylenically unsaturated bond, more preferably a (meth)acrylic monomer having an acid labile group.
Among (meth)acrylic monomers having an acid-labile group, those having an alicyclic hydrocarbon group having 5 to 20 carbon atoms are preferred. When the resin (A) having a structural unit derived from the monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group is used in the resist composition, the resolution of the resist pattern can be improved.

［式（ａ１－０）及び式（ａ１－２）中、
Ｌ^a01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^a7は、炭素数１～３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た基を表す。
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 a (meth)acrylic monomer having group (1) is preferably a structural unit represented by formula (a1-0) (hereinafter sometimes referred to as structural unit (a1-0).) Or a structural unit represented by formula (a1-2) (hereinafter sometimes referred to as structural unit (a1-2)). These may be used alone or in combination of two or more.

[In the formulas (a1-0) and (a1-2),
L ^a01 and L ^a2 each independently represent —O— or ^* —O—(CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, * is —CO— represents a bond with
R ^a01 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a02 , R ^a03 and R ^a04 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
R ^a7 represents an alkyl group having 1 to 3 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
n1 represents any integer from 0 to 10;
n1' represents an integer of 0 to 3; ]

R ^a01 and R ^a5 are preferably methyl groups.
L ^a01 and L ^a2 are preferably an oxygen atom or *—O—(CH ₂ ) _k01 —CO—O— (provided that k01 is preferably an integer of 1 to 4, more preferably 1 ), more preferably an oxygen atom.
The alkyl groups, alicyclic hydrocarbon groups and groups in which these are combined for R ^a02 , R ^a03 , R ^a04 and R ^a7 are the same as the groups listed for R ^a1 , R ^a2 and R ^a3 in formula (1). groups.
The alkyl group for R ^a02 , R ^a03 and R ^a04 preferably has 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group, still more preferably a methyl group.
The alkyl group for R ^a7 is preferably a methyl group, an ethyl group or an isopropyl group, more preferably an ethyl group or an isopropyl group.
The alicyclic hydrocarbon groups of R ^a02 , R ^a03 and R ^a04 preferably have 5 to 12 carbon atoms, more preferably 5 to 10 carbon atoms.
It is preferable that the combined group of an alkyl group and an alicyclic hydrocarbon group have a total carbon number of 18 or less.
R ^a02 and R ^a03 are preferably alkyl groups having 1 to 6 carbon atoms, more preferably methyl or ethyl groups.
R ^a04 is preferably an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 5 to 12 carbon atoms, more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group.
R ^a7 is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group, an ethyl group or an isopropyl group, still more preferably an ethyl group or an isopropyl group.
n1 is preferably an integer from 0 to 3, more preferably 0 or 1.
n1' is preferably 0 or 1.

As the structural unit (a1-0), for example, a structural unit represented by any one of formulas (a1-0-1) to (a1-0-12) and R ^a01 in the structural unit (a1-0) Structural units in which the corresponding methyl group is replaced with a hydrogen atom are exemplified, and structural units represented by any one of formulas (a1-0-1) to (a1-0-10) are preferred.

The structural unit (a1-2) corresponds to a structural unit represented by any one of formulas (a1-2-1) to (a1-2-6) and R ^a5 in the structural unit (a1-2). Structural units in which a methyl group is substituted with a hydrogen atom are included, and structural units represented by formulas (a1-2-2), (a1-2-5) and (a1-2-6) are preferred.

When the resin (A) contains the structural unit (a1-0) and/or the structural unit (a1-2), the total content of these is usually 5 to 85 mol with respect to the total structural units of the resin (A). %, preferably 7 to 70 mol %, more preferably 10 to 65 mol %, still more preferably 15 to 60 mol %, still more preferably 20 to 55 mol %.

［式（ａ１－４）中、
Ｒ^a32は、水素原子、ハロゲン原子、又は、ハロゲン原子を有してもよい炭素数１～６のアルキル基を表す。
Ｒ^a33は、ハロゲン原子、ヒドロキシ基、炭素数１～６のアルキル基、炭素数１～６のアルコキシ基、炭素数２～４のアルキルカルボニル基、炭素数２～４のアルキルカルボニルオキシ基、アクリロイルオキシ基又はメタクリロイルオキシ基を表す。
ｌａは０～４のいずれかの整数を表す。ｌａが２以上である場合、複数のＲ^a33は互いに同一であっても異なってもよい。
Ｒ^a34及びＲ^a35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^a36は、炭素数１～２０の炭化水素基を表すか、Ｒ^a35及びＲ^a36は互いに結合してそれらが結合する－Ｃ－Ｏ－とともに炭素数２～２０の２価の炭化水素基を形成し、該炭化水素基及び該２価の炭化水素基に含まれる－ＣＨ₂－は、－Ｏ－又は－Ｓ－で置き換わってもよい。］ Structural units having group (2) in structural unit (a1) include structural units represented by formula (a1-4) (hereinafter sometimes referred to as “structural unit (a1-4)”). .

[In formula (a1-4),
R ^a32 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a33 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl It represents an oxy group or a methacryloyloxy group.
la represents an integer of 0 to 4; When la is 2 or more, a plurality of R ^a33 may be the same or different.
R ^a34 and R ^a35 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^a36 represents a hydrocarbon group having 1 to 20 carbon atoms, or R ^a35 and R ^a36 are bonded to each other to form a C2-C20 divalent hydrocarbon group together with -C-O- to which they are bonded, and -CH ₂ - contained in the hydrocarbon group and the divalent hydrocarbon group is - O- or -S- may be substituted. ]

Examples of alkyl groups for R ^a32 and R ^a33 include methyl group, ethyl group, propyl group, isopropyl group, butyl group, pentyl group and hexyl group. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, even more preferably a methyl group.
Halogen atoms in R ^a32 and R ^a33 include fluorine, chlorine and bromine atoms.
Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom include trifluoromethyl group, difluoromethyl group, methyl group, perfluoroethyl group, 2,2,2-trifluoroethyl group, 1,1, 2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3, 4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group, etc. mentioned.
Alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentyloxy and hexyloxy groups. Among them, an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is even more preferable.
Alkylcarbonyl groups include acetyl, propionyl and butyryl groups.
An acetyloxy group, a propionyloxy group, a butyryloxy group, etc. are mentioned as an alkylcarbonyloxy group.
Examples of hydrocarbon groups for R ^a34 , R ^a35 and R ^a36 include alkyl groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups and groups in which these are combined. includes the same alkyl groups and alicyclic hydrocarbon groups as R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 .
Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl and biphenyl groups. group, phenanthryl group, 2,6-diethylphenyl group, aryl group such as 2-methyl-6-ethylphenyl group, and the like.
Examples of the combined group include a group obtained by combining the aforementioned alkyl group and an alicyclic hydrocarbon group, an aralkyl group such as a benzyl group, an aryl-cyclohexyl group such as a phenylcyclohexyl group, and the like. In particular, R ^a36 is an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group formed by combining these groups. is mentioned.

In formula (a1-4), R ^a32 is preferably a hydrogen atom.
R ^a33 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group, and even more preferably a methoxy group.
la is preferably 0 or 1, more preferably 0.
R ^a34 is preferably a hydrogen atom.
R ^a35 is preferably an alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group, more preferably a methyl group or an ethyl group.
The hydrocarbon group of R ^a36 is preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination of these A group to be formed, more preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms or an aralkyl group having 7 to 18 carbon atoms. The alkyl group and alicyclic hydrocarbon group in R ^a36 are preferably unsubstituted. The aromatic hydrocarbon group for R ^a36 is preferably an aromatic ring having an aryloxy group with 6 to 10 carbon atoms.
--OC(R ^a34 )(R ^a35 )-OR ^a36 in the structural unit (a1-4) is eliminated upon contact with an acid (eg, p-toluenesulfonic acid) to form a hydroxy group.

Examples of structural units (a1-4) include structural units derived from monomers described in JP-A-2010-204646. Preferably, structural units represented by formulas (a1-4-1) to (a1-4-12) and structures in which the hydrogen atom corresponding to R ^a32 in the structural unit (a1-4) is replaced with a methyl group units, more preferably structural units represented by formulas (a1-4-1) to (a1-4-5) and formula (a1-4-10).

When the resin (A) has the structural unit (a1-4), the content thereof is preferably 5 to 60 mol%, preferably 5 to 50 mol%, based on the total of all structural units of the resin (A). It is more preferably mol %, and even more preferably 10 to 40 mol %.

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。 Structural units derived from (meth)acrylic monomers having group (2) include structural units represented by formula (a1-5) (hereinafter sometimes referred to as “structural unit (a1-5)”). be done.

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

Halogen atoms include fluorine atoms and chlorine atoms, with fluorine atoms being preferred.
Examples of alkyl groups having 1 to 6 carbon atoms which may have a halogen atom include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, fluoromethyl and trifluoromethyl. groups.
In formula (a1-5), R ^a8 is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.
L ⁵¹ is preferably an oxygen atom.
Preferably, one of L ⁵² and L ⁵³ is —O— and the other is —S—.
As for s1, 1 is preferable.
s1' is preferably an integer of 0-2.
Z ^a1 is preferably a single bond or *—CH ₂ —CO—O—.

Examples of structural units (a1-5) include structural units derived from monomers described in JP-A-2010-61117. Among them, structural units represented by formulas (a1-5-1) to (a1-5-4) are preferable, and represented by formula (a1-5-1) or formula (a1-5-2) Structural units are more preferred.

When the resin (A) has the structural unit (a1-5), the content thereof is preferably 1 to 50 mol%, more preferably 3 to 45 mol%, based on the total structural units of the resin (A). , more preferably 5 to 40 mol %, and even more preferably 5 to 30 mol %.

［式（ａ１－０Ｘ）中、
Ｒ^x1は、水素原子又はメチル基を表す。
Ｒ^x2及びＲ^x3は、互いに独立に、炭素数１～６の飽和炭化水素基を表す。
Ａｒ^x1は、炭素数６～３６の芳香族炭化水素基を表す。］ Examples of the structural unit (a1) include structural units represented by formula (a1-0X) (hereinafter sometimes referred to as structural unit (a1-0X)).

[In the formula (a1-0X),
R ^x1 represents a hydrogen atom or a methyl group.
R ^x2 and R ^x3 each independently represent a saturated hydrocarbon group having 1 to 6 carbon atoms.
Ar ^x1 represents an aromatic hydrocarbon group having 6 to 36 carbon atoms. ]

Saturated hydrocarbon groups for R ^x2 and R ^x3 include alkyl groups, alicyclic hydrocarbon groups, and groups formed by combinations thereof.
Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl and hexyl groups.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and examples of monocyclic alicyclic hydrocarbon groups include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups.
Aromatic hydrocarbon groups for Ar ^x1 include aryl groups having 6 to 36 carbon atoms such as phenyl, naphthyl and anthryl groups.
The aromatic hydrocarbon group preferably has 6 to 24 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably a phenyl group.
Ar ^x1 is preferably an aromatic hydrocarbon group having 6 to 18 carbon atoms, more preferably a phenyl group or a naphthyl group, still more preferably a phenyl group.
R ^x1 , R ^x2 and R ^x3 are each independently preferably a methyl group or an ethyl group, more preferably a methyl group.

Examples of the structural unit (a1-0X) include the following structural units and compounds in which the methyl group corresponding to R ^x1 in the structural unit (a1-0X) is replaced with a hydrogen atom. Structural unit (a1-0X) is preferably structural unit (a1-0X-1) to structural unit (a1-0X-3).

When the resin (A) has the structural unit (a1-0X), the content thereof is preferably 5 to 60 mol%, more preferably 5 to 50 mol%, based on the total monomers in the resin (A). more preferably 10 to 40 mol %.
The resin (A) may contain two or more structural units (a1-0X).

The structural unit (a1) also includes the following structural units.

When the resin (A) contains the above structural unit, its content is preferably 5 to 60 mol%, more preferably 5 to 50 mol%, and 10 to 40 mol, based on the total structural units of the resin (A). % is more preferred.

<Structural unit (s)>
As a monomer leading to the structural unit (s), a monomer having no acid-labile group known in the field of resists can be used.
The structural unit (s) preferably has a hydroxy group or a lactone ring. A structural unit having a hydroxy group and no acid-labile group (hereinafter sometimes referred to as "structural unit (a2)") and/or a structure having a lactone ring and no acid-labile group When 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 adhesion to the substrate can be improved.

式（ａ２－１）中、
Ｌ^a3は、－Ｏ－又は^＊－Ｏ－（ＣＨ₂）_k2－ＣＯ－Ｏ－を表し、
ｋ２は１～７のいずれかの整数を表す。＊は－ＣＯ－との結合手を表す。
Ｒ^a14は、水素原子又はメチル基を表す。
Ｒ^a15及びＲ^a16は、それぞれ独立に、水素原子、メチル基又はヒドロキシ基を表す。
ｏ１は、０～１０のいずれかの整数を表す。 <Structural unit (a2)>
Examples of the hydroxy group possessed by the structural unit (a2) include an alcoholic hydroxy group, including the structural unit (a2-1) described below. As the structural unit (a2), one type may be contained alone, or two or more types may be contained.
A structural unit having an alcoholic hydroxy group in the structural unit (a2) includes a structural unit represented by formula (a2-1) (hereinafter sometimes referred to as "structural unit (a2-1)").

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

In formula (a2-1), L ^a3 is preferably —O—, —O—(CH ₂ ) _f1 —CO—O— (f1 represents 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 any integer from 0 to 3, more preferably 0 or 1.

Examples of structural units (a2-1) include structural units derived from monomers described in JP-A-2010-204646. Structural units represented by any one of formulas (a2-1-1) to (a2-1-6) are preferred, and any one of formulas (a2-1-1) to (a2-1-4) Structural units represented by the formula (a2-1-1) or (a2-1-3) are more preferable.

When the resin (A) contains the structural unit (a2-1), its content is usually 1 to 45 mol%, preferably 1 to 40 mol%, based on the total structural units of the resin (A). Yes, more preferably 1 to 35 mol %, still more preferably 1 to 20 mol %, still more preferably 1 to 10 mol %.

［式（ａ３－１）、式（ａ３－２）、式（ａ３－３）及び式（ａ３－４）中、
Ｌ^a4、Ｌ^a5及びＬ^a6は、それぞれ独立に、－Ｏ－又は＊－Ｏ－（ＣＨ_２）_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。
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。
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。
＊はカルボニル基との結合手を表す。
Ｒ^a18、Ｒ^a19及びＲ^a20は、それぞれ独立に、水素原子又はメチル基を表す。
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。
Ｘ^a3は、－ＣＨ_２－又は酸素原子を表す。
Ｒ^a21は炭素数１～４の脂肪族炭化水素基を表す。
Ｒ^a22、Ｒ^a23及びＲ^a25は、それぞれ独立に、カルボキシ基、シアノ基又は炭素数１～４の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。
ｑ１は、０～３のいずれかの整数を表す。
ｒ１は、０～３のいずれかの整数を表す。
ｗ１は、０～８のいずれかの整数を表す。
ｐ１、ｑ１、ｒ１及び／又はｗ１が２以上のとき、複数のＲ^a21、Ｒ^a22、Ｒ^a23及び／又はＲ^a25は互いに同一であってもよく、異なっていてもよい。］ <Structural unit (a3)>
The lactone ring of the structural unit (a3) may be a monocyclic ring such as a β-propiolactone ring, γ-butyrolactone ring, and δ-valerolactone ring. or heterocyclic ring). Preferable examples include a γ-butyrolactone ring, an adamantanelactone ring, or a bridged ring containing a γ-butyrolactone ring structure (for example, a structural unit represented by the following formula (a3-2)).
Structural unit (a3) is preferably a structural unit represented by formula (a3-1), formula (a3-2), formula (a3-3) or formula (a3-4). One of these may be contained alone, or two or more may be contained.

[In formula (a3-1), formula (a3-2), formula (a3-3) and formula (a3-4),
L ^a4 , L ^a5 and L ^a6 each independently represent -O- or *-O-(CH ₂ ) _k3 -CO-O- (k3 represents an integer of 1 to 7); represents a group.
L ^a7 is -O-, *-OL ^a8 -O-, *-OL ^a8 -CO-O-, *-OL ^a8 -CO-O-L ^a9 -CO-O- or * -O-L ^a8 -O-CO-L ^a9 -O-.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
* represents a bond with a carbonyl group.
R ^a18 , R ^a19 and R ^a20 each independently represent a hydrogen atom or a methyl group.
R ^a24 represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
X ^a3 represents —CH ₂ — or an oxygen atom.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
R ^a22 , R ^a23 and R ^a25 each independently represent a carboxy group, a cyano group or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents any integer from 0 to 5;
q1 represents an integer of 0 to 3;
r1 represents an integer of 0 to 3;
w1 represents any integer from 0 to 8;
When p1, q1, r1 and/or w1 are 2 or more, a plurality of R ^a21 , R ^a22 , R ^a23 and/or R ^a25 may be the same or different. ]

Examples of the aliphatic hydrocarbon group for R ^a21 , R ^a22 , R ^a23 and R ^a25 include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group and tert-butyl group. be done.
Halogen atoms in R ^a24 include fluorine, chlorine, bromine and iodine atoms.
Examples of the alkyl group for R ^a24 include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group and hexyl group, preferably having 1 to 4 carbon atoms. and more preferably a methyl group or an ethyl group.
The alkyl group having a halogen atom for R ^a24 includes a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, and a perfluoro A hexyl group, a trichloromethyl group, a tribromomethyl group, a triiodomethyl group and the like can be mentioned.
The alkanediyl group for L ^a8 and L ^a9 includes methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5 -diyl group, hexane-1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1, 4-diyl group, 2-methylbutane-1,4-diyl group and the like.

In formulas (a3-1) to (a3-3), L ^a4 to L ^a6 are each independently preferably —O— or *—O—(CH ₂ ) _k3 —CO—O—, k3 is an integer of 1 to 4, more preferably -O- and *-O-CH ₂ -CO-O-, 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 each independently preferably an integer of 0 to 2, 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, still more preferably a hydrogen atom or a methyl group is.
R ^a25 is preferably a carboxy group, a cyano group or a methyl group.
L ^a7 is preferably -O- or *-O-L ^a8 -CO-O-, more preferably -O-, -O-CH ₂ -CO-O- or -O-C ₂ H ₄ - It is CO—O—.
w1 is preferably an integer from 0 to 2, more preferably 0 or 1.
In particular, formula (a3-4) is preferably formula (a3-4)'.

(In the formula, R ^a24 and L ^a7 have the same meanings as above.)

As the structural unit (a3), the monomer described in JP-A-2010-204646, the monomer described in JP-A-2000-122294, the structure derived from the monomer described in JP-A-2012-41274 units. As the structural unit (a3), formula (a3-1-1), formula (a3-1-2), formula (a3-2-1), formula (a3-2-2), formula (a3-3- 1), a structural unit represented by any one of formulas (a3-3-2) and formulas (a3-4-1) to (a3-4-12), and in said structural unit, formula (a3-1 ) to R ^a18 , R ^a19 , R ^a20 and R ^a24 in formulas (a3-4) are preferably structural units in which methyl groups are replaced with hydrogen atoms.

When the resin (A) contains the structural unit (a3), the total content is usually 5 to 70 mol%, preferably 6 to 65 mol%, based on the total structural units of the resin (A). , more preferably 7 to 60 mol %.
Further, the content of structural unit (a3-1), structural unit (a3-2), structural unit (a3-3) or structural unit (a3-4) is 5 to 60 mol % is preferred, 5 to 50 mol % is more preferred, and 7 to 50 mol % is even more preferred.

［式（ａ４）中、
Ｒ⁴¹は、水素原子又はメチル基を表す。
Ｒ⁴²は、炭素数１～２４のフッ素原子を有する飽和炭化水素基を表し、該飽和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。］
Ｒ⁴²で表される飽和炭化水素基は、鎖式炭化水素基及び単環又は多環の脂環式炭化水素基、並びに、これらを組み合わせることにより形成される基等が挙げられる。 <Structural unit (a4)>
Structural units (a4) include the following structural units.

[In formula (a4),
R ⁴¹ represents a hydrogen atom or a methyl group.
R ⁴² represents a saturated hydrocarbon group having 1 to 24 fluorine atoms, and --CH ₂ -- contained in the saturated hydrocarbon group may be replaced with --O-- or --CO. ]
Examples of saturated hydrocarbon groups represented by R ⁴² include chain hydrocarbon groups, monocyclic or polycyclic alicyclic hydrocarbon groups, and groups formed by combining these groups.

組み合わせにより形成される基としては、１以上のアルキル基又は１以上のアルカンジイル基と、１以上の脂環式炭化水素基とを組み合わせることにより形成される基が挙げられ、－アルカンジイル基－脂環式炭化水素基、－脂環式炭化水素基－アルキル基、－アルカンジイル基－脂環式炭化水素基－アルキル基等が挙げられる。 Chain hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl groups. mentioned.
Monocyclic or polycyclic alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl; decahydronaphthyl, adamantyl, norbornyl and the following groups (* represents a bond) and other polycyclic alicyclic hydrocarbon groups.

Groups formed by combination include groups formed by combining one or more alkyl groups or one or more alkanediyl groups and one or more alicyclic hydrocarbon groups, and -alkanediyl groups- Alicyclic hydrocarbon group, -alicyclic hydrocarbon group-alkyl group, -alkanediyl group-alicyclic hydrocarbon group-alkyl group, and the like.

［式（ａ４－０）中、
Ｒ^5ａは、水素原子又はメチル基を表す。
Ｌ^4ａは、単結合又は炭素数１～４のアルカンジイル基を表す。
Ｌ^3ａ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。
Ｒ^6ａは、水素原子又はフッ素原子を表す。］ The structural unit (a4) is at least selected from the group consisting of formula (a4-0), formula (a4-1), formula (a4-2), formula (a4-3) and formula (a4-4) Structural units represented by one are exemplified.

[In the formula (a4-0),
R ^5a represents a hydrogen atom or a methyl group.
L ^4a represents a single bond or an alkanediyl group having 1 to 4 carbon atoms.
L ^3a represents a perfluoroalkanediyl group having 1 to 8 carbon atoms or a perfluorocycloalkanediyl group having 3 to 12 carbon atoms.
R ^6a represents a hydrogen atom or a fluorine atom. ]

The alkanediyl group for L ^4a includes linear alkanediyl groups such as methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, ethane-1,1-diyl, branched alkanediyl groups such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group; be done.
The perfluoroalkanediyl group for L ^3a 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 group. -2,2-diyl group, perfluorobutane-1,4-diyl group, perfluorobutane-2,2-diyl group, perfluorobutane-1,2-diyl group, perfluoropentane-1,5-diyl group, perfluoropentane -2,2-diyl group, perfluoropentane-3,3-diyl group, perfluorohexane-1,6-diyl group, perfluorohexane-2,2-diyl group, perfluorohexane-3,3-diyl group, perfluoroheptane -1,7-diyl group, perfluoroheptane-2,2-diyl group, perfluoroheptane-3,4-diyl group, perfluoroheptane-4,4-diyl group, perfluorooctane-1,8-diyl group, perfluorooctane -2,2-diyl group, perfluorooctane-3,3-diyl group, perfluorooctane-4,4-diyl group and the like.
The perfluorocycloalkanediyl group for L ^3a includes a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, a perfluoroadamantanediyl group, and the like.
L ^4a is preferably a single bond, a methylene group or an ethylene group, more preferably a single bond or a methylene group.
L ^3a is preferably a C 1-6 perfluoroalkanediyl group, more preferably a C 1-3 perfluoroalkanediyl group.

Examples of the structural unit (a4-0) include structural units shown below and structural units in which the methyl group corresponding to R ^5a in the structural unit (a4-0) in the following structural units is replaced with a hydrogen atom.

［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価の飽和炭化水素基を表す。
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。］

[In formula (a4-1),
R ^a41 represents a hydrogen atom or a methyl group.
R ^a42 represents an optionally substituted saturated hydrocarbon group having 1 to 20 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group is replaced with —O— or —CO— may
A ^a41 represents an optionally substituted alkanediyl group having 1 to 6 carbon atoms or a group represented by formula (a-g1). However, at least one of A ^a41 and R ^a42 has a halogen atom (preferably a fluorine atom) as a substituent.

[In the formula (a-g1),
s represents 0 or 1;
A ^a42 and A ^a44 each independently represent an optionally substituted divalent saturated hydrocarbon group having 1 to 5 carbon atoms.
A ^a43 represents a single bond or an optionally substituted C 1-5 divalent aliphatic hydrocarbon group.
X ^a41 and X ^a42 each independently represent -O-, -CO-, -CO-O- or -O-CO-.
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 . ]

組み合わせにより形成される基としては、１以上のアルキル基又は１以上のアルカンジイル基と、１以上の飽和脂環式炭化水素基とを組み合わせることにより形成される基が挙げられ、－アルカンジイル基－飽和脂環式炭化水素基、－飽和脂環式炭化水素基－アルキル基、－アルカンジイル基－飽和脂環式炭化水素基－アルキル基等が挙げられる。
Ｒ^a42が有していてもよい置換基としては、ハロゲン原子及び式（ａ－ｇ３）で表される基からなる群から選択される少なくとも１種が挙げられる。ハロゲン原子としては、フッ素原子、塩素原子、臭素原子及びヨウ素原子が挙げられ、好ましくはフッ素原子である。

［式（ａ－ｇ３）中、
Ｘ^a43は、酸素原子、カルボニル基、＊－Ｏ－ＣＯ－又は＊－ＣＯ－Ｏ－を表す（＊はＲ^a42との結合手を表す。）。
Ａ^a45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。
＊は結合手を表す。］
ただし、Ｒ^a42－Ｘ^a43－Ａ^a45において、Ｒ^a42がハロゲン原子を有しない場合は、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。
Ａ^a45における脂肪族炭化水素基としては、メチル基、エチル基、プロピル基、ブチル基、ペンチル基、ヘキシル基、ヘプチル基、オクチル基、デシル基、ドデシル基、ペンタデシル基、ヘキサデシル基、ヘプタデシル基及びオクタデシル基等のアルキル基；シクロペンチル基、シクロへキシル基、シクロヘプチル基、シクロオクチル基等の単環式の脂環式炭化水素基；並びにデカヒドロナフチル基、アダマンチル基、ノルボルニル基及び下記の基（＊は結合手を表す。）等の多環式の脂環式炭化水素基が挙げられる。

組み合わせにより形成される基としては、１以上のアルキル基又は１以上のアルカンジイル基と、１以上の脂環式炭化水素基とを組み合わせることにより形成される基が挙げられ、－アルカンジイル基－脂環式炭化水素基、－脂環式炭化水素基－アルキル基、－アルカンジイル基－脂環式炭化水素基－アルキル基等が挙げられる。 Examples of saturated hydrocarbon groups for R ^a42 include chain saturated hydrocarbon groups, monocyclic or polycyclic saturated alicyclic hydrocarbon groups, groups formed by combining these groups, and the like.
Chain saturated hydrocarbon groups include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group, dodecyl group, pentadecyl group, hexadecyl group, heptadecyl group and octadecyl group. are mentioned.
Examples of monocyclic or polycyclic saturated alicyclic hydrocarbon groups include cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and other cycloalkyl groups; decahydronaphthyl, adamantyl, norbornyl and the following polycyclic alicyclic saturated hydrocarbon groups such as groups (* represents a bond).

Groups formed by combination include groups formed by combining one or more alkyl groups or one or more alkanediyl groups and one or more saturated alicyclic hydrocarbon groups, and -alkanediyl groups -saturated alicyclic hydrocarbon group, -saturated alicyclic hydrocarbon group-alkyl group, -alkanediyl group-saturated alicyclic hydrocarbon group-alkyl group, and the like.
The substituent that R ^a42 may have includes at least one selected from the group consisting of halogen atoms and groups represented by formulas (a-g3). A halogen atom includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, preferably a fluorine atom.

[In the formula (a-g3),
X ^a43 represents an oxygen atom, a carbonyl group, *--O--CO-- or *--CO--O-- (* represents a bond with R ^a42 ).
A ^a45 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
* represents a bond. ]
However, in R ^a42 -X ^a43 -A ^a45 , when R ^a42 does not have a halogen atom, A ^a45 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms and having at least one halogen atom.
Aliphatic hydrocarbon groups for A ^a45 include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, pentadecyl, hexadecyl, heptadecyl and Alkyl groups such as octadecyl group; monocyclic alicyclic hydrocarbon groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* represents a bond) and other polycyclic alicyclic hydrocarbon groups.

Groups formed by combination include groups formed by combining one or more alkyl groups or one or more alkanediyl groups and one or more alicyclic hydrocarbon groups, and -alkanediyl groups- Alicyclic hydrocarbon group, -alicyclic hydrocarbon group-alkyl group, -alkanediyl group-alicyclic hydrocarbon group-alkyl group and the like.

R ^a42 is preferably a saturated hydrocarbon group which may have a halogen atom, more preferably an alkyl group having a halogen atom and/or a saturated hydrocarbon group having a group represented by formula (a-g3).
When R ^a42 is a saturated hydrocarbon group having a halogen atom, it is preferably a saturated hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, still more preferably having 1 to 1 carbon atoms. A perfluoroalkyl group having 6 carbon atoms, particularly preferably a perfluoroalkyl group having 1 to 3 carbon atoms. Perfluoroalkyl groups include perfluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, perfluorohexyl, perfluoroheptyl and perfluorooctyl groups. A perfluorocyclohexyl group etc. are mentioned as a perfluorocycloalkyl group.
When R ^a42 is a saturated hydrocarbon group having a group represented by formula (a-g3), the total carbon number of R ^a42 including the number of carbon atoms contained in the group represented by formula (a-g3) The number is preferably 15 or less, more preferably 12 or less. When it has a group represented by formula (a-g3) 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２価の飽和炭化水素基を表す。
Ｘ^a44は、＊－Ｏ－ＣＯ－又は＊－ＣＯ－Ｏ－を表す（＊はＡ^a46との結合手を表す。）。
Ａ^a47は、ハロゲン原子を有していてもよい炭素数１～１７の脂肪族炭化水素基を表す。
ただし、Ａ^a46、Ａ^a47及びＸ^a44の炭素数の合計は１８以下であり、Ａ^a46及びＡ^a47のうち、少なくとも一方は、少なくとも１つのハロゲン原子を有する。
＊はカルボニル基との結合手を表す。］ When R ^a42 is a saturated hydrocarbon group having a group represented by formula (a-g3), R ^a42 is more preferably a group represented by formula (a-g2).

[In the formula (a-g2),
A ^a46 represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
X ^a44 represents *-O-CO- or *-CO-O- (* represents a bond with A ^a46 ).
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 saturated hydrocarbon group of A ^a46 preferably has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms.
The number of carbon atoms in the aliphatic hydrocarbon group of A ^a47 is preferably 4 to 15, more preferably 5 to 12, and A ^a47 is more preferably a cyclohexyl group or an adamantyl group.
A preferred structure of the group represented by formula (a-g2) is the following structure (* is a bond with a carbonyl group).

Alkanediyl group for A ^a41 includes methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group and hexane-1,6-diyl group straight-chain alkanediyl groups such as; A branched alkanediyl group such as a 2-methylbutane-1,4-diyl group can be mentioned.
Examples of substituents on 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 still more preferably an ethylene group.

The divalent saturated hydrocarbon groups represented by A ^a42 , A ^a43 and A ^a44 in the group represented by formula (a-g1) include linear or branched alkanediyl groups and monocyclic or polycyclic divalent Examples thereof include alicyclic hydrocarbon groups and groups formed by combining an alkanediyl group and a divalent alicyclic hydrocarbon group. Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group and the like.
Substituents of the divalent saturated hydrocarbon groups represented by A ^a42 , A ^a43 and A ^a44 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
s is preferably zero.
Among the groups represented by the formula (a-g1), examples of groups in which X ^a42 is -O-, -CO-, -CO-O- or -O-CO- include the following groups. In the following examples, * and ** each represent a bond, and ** is a bond with --O--CO--R ^a42 .

As the structural unit represented by formula (a4-1), the following structural units and the methyl group corresponding to R ^a41 in the structural unit represented by formula (a4-1) in the following structural units is replaced with a hydrogen atom. Structural units replaced are included.

［式（ａ４－２）中、
Ｒ^f5は、水素原子又はメチル基を表す。
Ｌ⁴⁴は、炭素数１～６のアルカンジイル基を表し、該アルカンジイル基に含まれる－ＣＨ₂－は、－Ｏ－又は－ＣＯ－に置き換わっていてもよい。
Ｒ^f6は、炭素数１～２０のフッ素原子を有する飽和炭化水素基を表す。
ただし、Ｌ⁴⁴及びＲ^f6の合計炭素数の上限は２１である。］ As the structural unit represented by formula (a4-1), a structural unit represented by formula (a4-2) is preferable.

[In formula (a4-2),
R ^f5 represents a hydrogen atom or a methyl group.
L ⁴⁴ represents an alkanediyl group having 1 to 6 carbon atoms, and --CH ₂ -- contained in the alkanediyl group may be replaced with --O-- or --CO--.
R ^f6 represents a saturated hydrocarbon group having 1 to 20 carbon atoms and a fluorine atom.
However, the upper limit of the total carbon number of L ⁴⁴ and R ^f6 is 21. ]

Examples of the alkanediyl group for L ⁴⁴ include the same groups as those exemplified for L ^4a .
Examples of the saturated hydrocarbon group for R ^f6 include the same groups as those exemplified for R ^a42 .
The alkanediyl group for L ⁴⁴ is preferably an alkanediyl group having 2 to 4 carbon atoms, more preferably an ethylene group.
Examples of structural units represented by formula (a4-2) include structural units represented by formulas (a4-1-1) to (a4-1-11). A structural unit in which the methyl group corresponding to R ^f5 in the structural unit (a4-2) is replaced with a hydrogen atom is also included as the structural unit represented by the formula (a4-2).

［式（ａ４－３）中、
Ｒ^f7は、水素原子又はメチル基を表す。
Ｌ⁵は、炭素数１～６のアルカンジイル基を表す。
Ａ^f13は、フッ素原子を有していてもよい炭素数１～１８の２価の飽和炭化水素基を表す。
Ｘ^f12は、＊－Ｏ－ＣＯ－又は＊－ＣＯ－Ｏ－を表す（＊はＡ^f13との結合手を表す。）。
Ａ^f14は、フッ素原子を有していてもよい炭素数１～１７の飽和炭化水素基を表す。
但し、Ａ^f13及びＡ^f14の少なくとも１つは、フッ素原子を有し、Ｌ⁵、Ａ^f13及びＡ^f14の合計炭素数の上限は２０である。］

[In formula (a4-3),
R ^f7 represents a hydrogen atom or a methyl group.
L ⁵ represents an alkanediyl group having 1 to 6 carbon atoms.
A ^f13 represents a C 1-18 divalent saturated hydrocarbon group which may have a fluorine atom.
X ^f12 represents *-O-CO- or *-CO-O- (* represents a bond with A ^f13 ).
A ^f14 represents a C 1-17 saturated hydrocarbon group which may have a fluorine atom.
However, at least one of A ^f13 and A ^f14 has a fluorine atom, and the upper limit of the total carbon number of L ⁵ , A ^f13 and A ^f14 is 20. ]

The alkanediyl group for L ⁵ includes the same groups as those exemplified for the alkanediyl group for L ^4a .
The divalent saturated hydrocarbon group which may have a fluorine atom in A ^f13 preferably has a divalent chain saturated hydrocarbon group which may have a fluorine atom and a fluorine atom is a divalent saturated alicyclic hydrocarbon group, more preferably a perfluoroalkanediyl group.
Examples of divalent chain hydrocarbon groups which may have a fluorine atom include alkanediyl groups such as a methylene group, an ethylene group, a propanediyl group, a butanediyl group and a pentanediyl group; and perfluoroalkanediyl groups such as a propanediyl group, a perfluorobutanediyl group and a perfluoropentanediyl group.
The divalent alicyclic hydrocarbon group which may have a fluorine atom may be either monocyclic or polycyclic. Monocyclic groups include a cyclohexanediyl group, a perfluorocyclohexanediyl group, and the like. Examples of polycyclic groups include an adamantanediyl group, a norbornanediyl group, a perfluoroadamantanediyl group, and the like.
Examples of saturated hydrocarbon groups and optionally fluorine-containing saturated hydrocarbon groups for A ^f14 include groups similar to those exemplified for R ^a42 . Among them, trifluoromethyl group, difluoromethyl group, methyl group, perfluoroethyl group, 2,2,2-trifluoroethyl group, 1,1,2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3,4,4-octafluorobutyl group, butyl group, perfluoropentyl group, Fluorination such as 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group, heptyl group, perfluoroheptyl group, octyl group and perfluorooctyl group Alkyl group, cyclopropylmethyl group, cyclopropyl group, cyclobutylmethyl group, cyclopentyl group, cyclohexyl group, perfluorocyclohexyl group, adamantyl group, adamantylmethyl group, adamantyldimethyl group, norbornyl group, norbornylmethyl group, perfluoroadamantyl group , a perfluoroadamantylmethyl group, and the like.

In formula (a4-3), L ⁵ is preferably an ethylene group.
The divalent saturated hydrocarbon group of A ^f13 is preferably a group containing a divalent chain hydrocarbon group having 1 to 6 carbon atoms and a divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms. A 2-3 divalent chain hydrocarbon group is more preferred.
The saturated hydrocarbon group of A ^f14 is preferably a group containing a chain hydrocarbon group having 3 to 12 carbon atoms and an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and a chain hydrocarbon group having 3 to 10 carbon atoms. and a group containing an alicyclic hydrocarbon group having 3 to 10 carbon atoms is more preferred. Among them, A ^f14 is preferably a group containing an alicyclic hydrocarbon group having 3 to 12 carbon atoms, more preferably a cyclopropylmethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group and an adamantyl group.

Examples of structural units represented by formula (a4-3) include structural units represented by formulas (a4-1′-1) to (a4-1′-11). A structural unit in which the methyl group corresponding to R ^f7 in the structural unit (a4-3) is replaced with a hydrogen atom is also included as the structural unit represented by the formula (a4-3).

［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の飽和炭化水素基を表す。］ Structural units (a4) also include structural units represented by formula (a4-4).

[In formula (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 C 1-10 saturated hydrocarbon group having a fluorine atom. ]

The saturated hydrocarbon group represented by R ^f22 includes the same saturated hydrocarbon group represented by R ^a42 .
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, more preferably an alkyl group having 1 to 10 carbon atoms having a fluorine atom. An alkyl group having 1 to 6 carbon atoms and having a fluorine atom is more preferred.
In formula (a4-4), A ^f21 is preferably —(CH ₂ ) _j1 —, more preferably an ethylene group or a methylene group, even more preferably a methylene group.

As the structural unit represented by formula (a4-4), for example, in structural units represented by the following structural units and structural units represented by the following formulas, the methyl group corresponding to R ^f21 in structural unit (a4-4) is hydrogen Structural units replaced with atoms are included.

When the resin (A) has the structural unit (a4), the content thereof is preferably 1 to 20 mol%, more preferably 2 to 15 mol%, based on the total structural units of the resin (A), and 3 ~10 mol% is more preferred.

［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。
Ｌ⁵⁵は、単結合又は炭素数１～１８の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる－ＣＨ_２－は、－Ｏ－又は－ＣＯ－に置き換わっていてもよい。］ <Structural unit (a5)>
Examples of non-leaving hydrocarbon groups possessed by the structural unit (a5) include groups having linear, branched or cyclic hydrocarbon groups. Among them, the structural unit (a5) is preferably a group having an alicyclic hydrocarbon group.
Examples of the structural unit (a5) include structural units represented by formula (a5-1).

[In the formula (a5-1),
^R51 represents a hydrogen atom or a methyl group.
R ⁵² represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with 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 —CH ₂ — contained in the saturated hydrocarbon group may be replaced with —O— or —CO— . ]

The alicyclic hydrocarbon group for R ⁵² may be either monocyclic or polycyclic. Examples of monocyclic alicyclic hydrocarbon groups include cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl groups. Examples of polycyclic alicyclic hydrocarbon groups include adamantyl groups and norbornyl groups.
Aliphatic hydrocarbon groups having 1 to 8 carbon atoms are, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group and 2 - alkyl groups such as ethylhexyl groups.
A 3-methyladamantyl group etc. are mentioned as an alicyclic hydrocarbon group which has a substituent.
R ⁵² is preferably an unsubstituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, more preferably an adamantyl group, a norbornyl group or a cyclohexyl group.
The divalent saturated hydrocarbon group for L ⁵⁵ includes a divalent saturated chain hydrocarbon group and a saturated divalent alicyclic hydrocarbon group, preferably a saturated chain divalent hydrocarbon group. .
Examples of divalent chain saturated hydrocarbon groups include alkanediyl groups such as methylene, ethylene, propanediyl, butanediyl and pentanediyl groups.
The bivalent alicyclic saturated hydrocarbon group may be either monocyclic or polycyclic. The monocyclic alicyclic saturated hydrocarbon group includes cycloalkanediyl groups such as cyclopentanediyl group and cyclohexanediyl group. Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include an adamantanediyl group and a norbornanediyl group.

式（Ｌ１－１）中、
Ｘ^x1は、＊－Ｏ－ＣＯ－又は＊－ＣＯ－Ｏ－を表す（＊はＬ^x１との結合手を表す。）。
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。 Groups in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ⁵⁵ is replaced with —O— or —CO— include, for example, formulas (L1-1) to (L1-4) and the group represented by In the formula below, * and ** each represent a bond, and * represents a bond with an oxygen atom.

In formula (L1-1),
X ^x1 represents *-O-CO- or *-CO-O- (* represents a bond with L ^x1 ).
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 carbon number 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 carbon number 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 carbon number of L ^x5 , L ^x6 and L ^x7 is 15 or less.
In formula (L1-4),
L ^x8 and L ^x9 each represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms.
W ^x1 represents a divalent saturated alicyclic hydrocarbon group having 3 to 15 carbon atoms.
However, the total carbon number of L ^x8 , L ^x9 and W ^x1 is 15 or less.

L ^x1 is preferably a C 1-8 divalent aliphatic saturated hydrocarbon group, more preferably a methylene group or an ethylene group.
L ^x2 is preferably a single bond or a C 1-8 divalent saturated aliphatic hydrocarbon group, 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 C 1-8 divalent aliphatic saturated hydrocarbon group, more preferably a methylene group or an ethylene group.
L ^x6 is preferably a single bond or a C 1-8 divalent aliphatic saturated hydrocarbon group, 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 saturated aliphatic hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond or a methylene group.
L ^x9 is preferably a single bond or a divalent saturated aliphatic hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond or a methylene group.
W ^x1 is preferably a divalent saturated alicyclic hydrocarbon group having 3 to 10 carbon atoms, more preferably a cyclohexanediyl group or an adamantanediyl group.

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

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

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

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

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

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

樹脂（Ａ）が、構造単位（ａ５）を有する場合、その含有率は、樹脂（Ａ）の全構造単位に対して、１～３０モル％が好ましく、２～２０モル％がより好ましく、３～１５モル％がさらに好ましい。

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

<Structural unit (II)>
The resin (A) may further contain a structural unit that is decomposed by exposure to generate an acid (hereinafter sometimes referred to as "structural unit (II)"). includes structural units described in JP-A-2016-79235, a structural unit having a sulfonate group or a carboxylate group and an organic cation in the side chain or a structural unit having a sulfonio group and an organic anion in the side chain. Preferably.

［式（ＩＩ－２－Ａ’）中、
Ｘ^III3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－ＣＨ_２－は、－Ｏ－、－Ｓ－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、ハロゲン原子、ハロゲン原子を有していてもよい炭素数１～６のアルキル基又はヒドロキシ基で置き換わっていてもよい。
Ａ^x1は、炭素数１～８のアルカンジイル基を表し、該アルカンジイル基に含まれる水素原子は、フッ素原子又は炭素数１～６のペルフルオロアルキル基で置換されていてもよい。
ＲＡ^－は、スルホナート基又はカルボキシレート基を表す。
Ｒ^III3は、水素原子、ハロゲン原子又はハロゲン原子を有していてもよい炭素数１～６のアルキル基を表す。
ＺＡ^＋は、有機カチオンを表す。］ A structural unit having a sulfonate group or carboxylate group and an organic cation in a side chain is preferably a structural unit represented by formula (II-2-A').

[In the formula (II-2-A '),
X ^III3 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced with —O—, —S— or —CO— A hydrogen atom contained in the saturated hydrocarbon group may be replaced with a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, or a hydroxy group.
A ^x1 represents an alkanediyl group having 1 to 8 carbon atoms, and a hydrogen atom contained in the alkanediyl group may be substituted with a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
^RA- represents a sulfonate group or a carboxylate group.
R ^III3 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
ZA ⁺ represents an organic cation. ]

Halogen atoms represented by R ^III3 include fluorine, chlorine, bromine and iodine atoms.
The alkyl group having 1 to 6 carbon atoms and optionally having a halogen atom represented by R ^III3 includes an alkyl group having 1 to 6 carbon atoms and optionally having a halogen atom represented by R ^a8 . The same can be mentioned.
The alkanediyl group having 1 to 8 carbon atoms represented by A ^x1 includes methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group and pentane-1,5-diyl group. , hexane-1,6-diyl 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-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group, etc. mentioned.
The perfluoroalkyl group having 1 to 6 carbon atoms which may be substituted on A ^x1 includes a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, and a perfluorotert -butyl group, perfluoropentyl group, perfluorohexyl group and the like.
Examples of the divalent saturated hydrocarbon group having 1 to 18 carbon atoms represented by X ^III3 include a linear or branched alkanediyl group and a monocyclic or polycyclic bivalent alicyclic saturated hydrocarbon group. and may be a combination of these.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1 ,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group , dodecane-1,12-diyl group and other linear alkanediyl groups; butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group , pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group and other branched alkanediyl groups; cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1 ,4-diyl group, cycloalkanediyl group such as cyclooctane-1,5-diyl group; norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane Divalent polycyclic alicyclic saturated hydrocarbon groups such as -2,6-diyl group and the like can be mentioned.
Examples of saturated hydrocarbon groups in which —CH ₂ — is replaced with —O—, —S— or —CO— include divalent groups represented by formulas (X1) to (X53). mentioned. However, each —CH ₂ — contained in the saturated hydrocarbon group has 17 or less carbon atoms before being replaced with —O—, —S— or —CO—. In the formula below, * and ** represent binding sites, and * represents a bond with A ^x1 .

X ³ represents a divalent saturated hydrocarbon group having 1 to 16 carbon atoms.
X ⁴ represents a divalent saturated hydrocarbon group having 1 to 15 carbon atoms.
X ⁵ represents a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.
X ⁶ represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms.
X ⁷ represents a trivalent saturated hydrocarbon group having 1 to 14 carbon atoms.
X ⁸ represents a divalent saturated hydrocarbon group having 1 to 13 carbon atoms.

Organic cations represented by ZA ⁺ include organic onium cations such as organic sulfonium cations, organic iodonium cations, organic ammonium cations, organic benzothiazolium cations and organic phosphonium cations, and organic sulfonium cations and organic iodonium cations. are preferred, and arylsulfonium cations are more preferred.
Examples of ZA ⁺ in formula (II-2-A′) include the same organic cations Z ⁺ in acid generator (B1) described later.

［式（ＩＩ－２－Ａ）中、Ｒ^III3、Ｘ^III3及びＺＡ^＋は、上記と同じ意味を表す。
ｚ２Ａは、０～６のいずれかの整数を表す。
Ｒ^III2及びＲ^III4は、それぞれ独立して、水素原子、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し、ｚ２Ａが２以上のとき、複数のＲ^III2及びＲ^III4は互いに同一であってもよいし、異なっていてもよい。
Ｑ^ａ及びＱ^ｂは、それぞれ独立して、フッ素原子又は炭素数１～６のペルフルオロアルキル基を表す。］
Ｒ^III2、Ｒ^III4、Ｑ^ａ及びＱ^ｂで表される炭素数１～６のペルフルオロアルキル基としては、後述のＱ^b1で表される炭素数１～６のペルフルオロアルキル基と同じものが挙げられる。 The structural unit represented by formula (II-2-A') is preferably a structural unit represented by formula (II-2-A).

[In formula (II-2-A), R ^III3 , X ^III3 and ZA ⁺ have the same meanings as above.
z2A represents an integer of 0-6.
R ^III2 and R ^III4 each independently represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and when z2A is 2 or more, a plurality of R ^III2 and R ^III4 are the same may be different.
Q ^a and Q ^b each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group. ]
Examples of the perfluoroalkyl group having 1 to 6 carbon atoms represented by R ^III2 , R ^III4 , Q ^a and Q ^b include the same perfluoroalkyl groups having 1 to 6 carbon atoms represented by Q ^b1 described later. .

［式（ＩＩ－２－Ａ－１）中、
Ｒ^III2、Ｒ^III3、Ｒ^III4、Ｑ^a、Ｑ^b及びＺＡ^＋は、上記と同じ意味を表す。
Ｒ^III5は、炭素数１～１２の飽和炭化水素基を表す。
ｚ２Ａ１は、０～６のいずれかの整数を表す。
Ｘ^I2は、炭素数１～１１の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる－ＣＨ_２－は、－Ｏ－、－Ｓ－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、ハロゲン原子又はヒドロキシ基で置換されていてもよい。］ The structural unit represented by formula (II-2-A) is preferably a structural unit represented by formula (II-2-A-1).

[In formula (II-2-A-1),
R ^III2 , R ^III3 , R ^III4 , Q ^a , Q ^b and ZA ⁺ have the same meanings as above.
R ^III5 represents a saturated hydrocarbon group having 1 to 12 carbon atoms.
z2A1 represents an integer of 0-6.
X ^I2 represents a divalent saturated hydrocarbon group having 1 to 11 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced with —O—, —S— or —CO—. A hydrogen atom contained in the saturated hydrocarbon group may be substituted with a halogen atom or a hydroxy group. ]

Examples of saturated hydrocarbon groups having 1 to 12 carbon atoms represented by R ^III5 include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, Linear or branched alkyl groups such as heptyl group, octyl group, nonyl group, decyl group, undecyl group and dodecyl group can be mentioned.
As the divalent saturated hydrocarbon group represented by X ^I2 , the same divalent saturated hydrocarbon groups as those represented by X ^III3 can be mentioned.

［式（ＩＩ－２－Ａ－２）中、Ｒ^III3、Ｒ^III5及びＺＡ^＋は、上記と同じ意味を表す。
ｍ及びｎは、互いに独立に、１又は２を表す。］ As the structural unit represented by formula (II-2-1), a structural unit represented by formula (II-2-A-2) is preferable.

[In formula (II-2-A-2), R ^III3 , R ^III5 and ZA ⁺ have the same meanings as above.
m and n each independently represent 1 or 2; ]

The structural unit represented by formula (II-2-A′) includes, for example, the following structural units and structural units described in International Publication No. 2012/050015. ZA ⁺ represents an organic cation.

［式（ＩＩ－１－１）中、
Ａ^II1は、単結合又は２価の連結基を表す。
Ｒ^II1は、炭素数６～１８の２価の芳香族炭化水素基を表す。
Ｒ^II2及びＲ^II3は、それぞれ独立して、炭素数１～１８の炭化水素基を表し、Ｒ^II2及びＲ^II3は互いに結合してそれらが結合する硫黄原子とともに環を形成していてもよい。
Ｒ^II4は、水素原子、ハロゲン原子又はハロゲン原子を有してもよい炭素数１～６のアルキル基を表す。
Ａ^－は、有機アニオンを表す。］
Ｒ^II1で表される炭素数６～１８の２価の芳香族炭化水素基としては、フェニレン基及びナフチレン基等が挙げられる。
Ｒ^II2及びＲ^II3で表される炭化水素基としては、アルキル基、脂環式炭化水素基、芳香族炭化水素基及びこれらを組み合わせることにより形成される基等が挙げられる。
Ｒ^II4で表されるハロゲン原子としては、フッ素原子、塩素原子、臭素原子及びヨウ素原子等が挙げられる。
Ｒ^II4で表されるハロゲン原子を有していてもよい炭素数１～６のアルキル基としては、Ｒ^a8で表されるハロゲン原子を有していてもよい炭素数１～６のアルキル基と同じものが挙げられる。
Ａ^II1で表される２価の連結基としては、例えば、炭素数１～１８の２価の飽和炭化水素基が挙げられ、該２価の飽和炭化水素基に含まれる－ＣＨ_２－は、－Ｏ－、－Ｓ－又は－ＣＯ－で置き換わっていてもよい。具体的には、Ｘ^III3で表される炭素数１～１８の２価の飽和炭化水素基と同じものが挙げられる。 A structural unit having a cation having a sulfonio group in its side chain and an organic anion is preferably a structural unit represented by formula (II-1-1).

[In the formula (II-1-1),
^AII1 represents a single bond or a divalent linking group.
R ^II1 represents a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^II2 and R ^II3 each independently represent a hydrocarbon group having 1 to 18 carbon atoms, and R ^II2 and R ^II3 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.
R ^II4 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
A ⁻ represents an organic anion. ]
Examples of the divalent aromatic hydrocarbon group having 6 to 18 carbon atoms represented by R ^II1 include a phenylene group and a naphthylene group.
The hydrocarbon groups represented by R ^II2 and R ^II3 include alkyl groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups and groups formed by combining these groups.
Halogen atoms represented by R ^II4 include fluorine, chlorine, bromine and iodine atoms.
The alkyl group having 1 to 6 carbon atoms and optionally having a halogen atom represented by R ^II4 includes an alkyl group having 1 to 6 carbon atoms and optionally having a halogen atom represented by R ^a8 . The same can be mentioned.
The divalent linking group represented by A ^II1 includes, for example, a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group is -O-, -S- or -CO- may be substituted. Specific examples thereof include the same divalent saturated hydrocarbon groups having 1 to 18 carbon atoms represented by ^XIII3 .

Examples of structural units containing cations in formula (II-1-1) include structural units represented below.

Organic anions represented by A ⁻ include sulfonate anions, sulfonylimide anions, sulfonylmethide anions and carboxylate anions. The organic anion represented by A ⁻ is preferably a sulfonate anion, and the sulfonate anion is more preferably an anion contained in a salt represented by formula (B1) described later.

Sulfonylimide anions represented by A ⁻ include the following.

Sulfonylmethide anions include the following.

Carboxylate anions include the following.

Examples of structural units represented by formula (II-1-1) include structural units represented below.

When the resin (A) contains the structural unit (II), the content of the structural unit (II) is preferably 1 to 20 mol% of the total structural units of the resin (A), and more It is preferably 2 to 15 mol %, more preferably 3 to 10 mol %.

Resin (A) may have structural units other than the structural units described above, and examples of such structural units include structural units well known in the art.

Resin (A) is preferably a resin comprising structural unit (I), structural unit (a1-1) and structural unit (a2-A), structural unit (I), structural unit (a1-1) and structural Resin composed of unit (a2-A) and structural unit (a1-2), resin composed of structural unit (I), structural unit (a1-1), structural unit (a2-A) and structural unit (s) , a resin comprising the structural unit (I), the structural unit (a1-1), the structural unit (a2-A), the structural unit (a1-2) and the structural unit (s), the structural unit (I) and the structural unit ( a1-1), a structural unit (a2-A), a structural unit (a1-2), a structural unit (s), a structural unit (a4) and/or a structural unit (a5), or a resin consisting of a structural unit ( I), the structural unit (a1-1), the structural unit (a2-A) and the structural unit (a4), more preferably the structural unit (I), the structural unit (a1-1) and the structural unit a resin consisting of the unit (a2-A), a resin consisting only of the structural unit (I), the structural unit (a1-1), the structural unit (a2-A) and the structural unit (a1-2), the structural unit (I ), a structural unit (a1-1), a structural unit (a2-A), and a structural unit (s), or a structural unit (I), a structural unit (a1-1), and a structural unit (a2-A) It is a resin composed of a structural unit (a1-2) and a structural unit (s).

Structural unit (s) is preferably at least one selected from the group consisting of structural unit (a2) and structural unit (a3). Structural unit (a2) is preferably structural unit (a2-1). Structural unit (a3) is preferably a structural unit represented by formula (a3-1), a structural unit represented by formula (a3-2), a structural unit represented by formula (a3x-2) and a structural unit represented by formula ( It is at least one selected from the group consisting of structural units represented by a3-4).

Each structural unit that constitutes the resin (A) may be used alone or in combination of two or more, and is produced by a known polymerization method (e.g., radical polymerization method) using a monomer that leads to these structural units. be able to. The content of each structural unit in the resin (A) can be adjusted by adjusting the amount of monomer used for 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, further preferably 15,000 or less).
As used herein, the weight average molecular weight is a value determined by gel permeation chromatography. Gel permeation chromatography can be measured under the analysis conditions described in Examples.

[Resist composition]
The resist composition of the present invention preferably contains a resin (A) and an acid generator known in the resist field (hereinafter sometimes referred to as "acid generator (B)").
The resist composition of the present invention may further contain a resin other than resin (A).
The resist composition of the present invention preferably contains a quencher (hereinafter sometimes referred to as "quencher (C)") such as a salt that generates an acid that is weaker in acidity than the acid generated by the acid generator. , a solvent (hereinafter sometimes referred to as "solvent (E)").

<Resins other than resin (A)>
The resist composition of the present invention may further contain a resin other than resin (A).
The resin other than the resin (A) may be any resin that does not contain the structural unit (I) or the structural unit (a2-A). Such resins include, for example, a resin obtained by removing the structural unit (I) from the resin (A) (hereinafter sometimes referred to as "resin (AY)"), and a resin obtained by removing the structural unit (a2-A) from the resin (A). The resin (hereinafter sometimes referred to as "resin (AZ)"), the resin (hereinafter sometimes referred to as "resin (X)") consisting only of the structural unit (a4) and the structural unit (a5), and the like can be mentioned.

As the resin (X), among others, a resin containing the structural unit (a4) is preferable. That is, it is preferably a resin containing a structural unit having a fluorine atom.
In the resin (X), the content of the structural unit (a4) is preferably 30 mol% or more, more preferably 40 mol% or more, based on the total of all structural units of the resin (X). , more preferably 45 mol % or more.
Structural units that the resin (X) may further include structural units (a2), structural units (a3), and structural units derived from other known monomers. Among them, the resin (X) is preferably a resin consisting only of the structural unit (a4) and/or the structural unit (a5).

Each structural unit that constitutes the resin (X) may be used alone or in combination of two or more. Using a monomer that induces these structural units, the polymer is produced by a known polymerization method (e.g., radical polymerization method). can do. The content of each structural unit in the resin (X) can be adjusted by adjusting the amount of the monomer used for polymerization.
The weight average molecular weights of resin (AY), resin (AZ) and resin (X) are each independently 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 weights of resin (AY), resin (AZ) and resin (X) are the same as in the case of resin (A).
When the resist composition of the present invention contains the resin (AY) and/or the resin (AZ), the total content thereof is usually 1 to 2500 parts by mass (more preferably is 10 to 1000 parts by mass).
Further, when the resist composition contains the resin (X), its content is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, relative to 100 parts by mass of the resin (A). , More preferably 1 to 40 parts by mass, particularly preferably 1 to 30 parts by mass, particularly preferably 1 to 8 parts by mass.

In the resist composition of the present invention, the resin (A) may be used in combination with a resin other than the resin (A). and/or a resin containing a structural unit having a fluorine atom is preferably used in combination, and it is more preferable to use the resin (AY), the resin (AZ) and/or the resin (X) in combination.
The resin (A) content in the resist composition is preferably 80% by mass or more and 99% by mass or less, more preferably 90 to 99% by mass, based on the solid content of the resist composition. Further, when a resin other than the resin (A) is included, the total content of the resin (A) and the resin other than the resin (A) is 80% by mass or more and 99% by mass with respect to the solid content of the resist composition. It is preferably below, more preferably 90 to 99% by mass. The solid content and resin content of the resist composition can be measured by known analytical means such as liquid chromatography or gas chromatography.

<Acid generator (B)>
The acid generator (B) may be either nonionic or ionic. Nonionic acid generators include sulfonate esters (eg 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonate), sulfones (eg disulfone, ketosulfone, sulfonyldiazomethane) and the like. Typical ionic acid generators are onium salts containing onium cations (eg, diazonium salts, phosphonium salts, sulfonium salts, iodonium salts). The anions of the onium salts include sulfonate anions, sulfonylimide anions, sulfonylmethide anions, and the like.
Examples of the acid generator (B) include JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038, JP-A-63-163452, JP-A-62-153853, JP-A-63-146029, US Pat. No. 3,779,778, US Pat. A compound that generates an acid upon exposure to radiation as described in 1. above can be used. Moreover, you may use the compound manufactured by the well-known method. The acid generator (B) may be used in combination of two or more.

［式（Ｂ１）中、
Ｑ^b1及びＱ^b2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１～２４の２価の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる－ＣＨ_２－は、－Ｏ－又は－ＣＯ－に置き換わっていてもよく、該２価の飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基で置換されていてもよい。
Ｙは、置換基を有していてもよいメチル基又は置換基を有していてもよい炭素数３～１８の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれる－ＣＨ_２－は、－Ｏ－、－Ｓ（Ｏ）_２－又は－ＣＯ－に置き換わっていてもよい。
Ｚ^＋は、有機カチオンを表す。］ The acid generator (B) is preferably a fluorine-containing acid generator, more preferably a salt represented by formula (B1) (hereinafter sometimes referred to as "acid generator (B1)").

[In the formula (B1),
Q ^b1 and Q ^b2 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced with —O— or —CO— , a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Y represents an optionally substituted methyl group or an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, included in the alicyclic hydrocarbon group- CH ₂ - may be replaced by -O-, -S(O) ₂ - or -CO-.
Z ⁺ represents an organic cation. ]

The perfluoroalkyl groups represented by Q ^b1 and Q ^b2 include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group and A perfluorohexyl group and the like can be mentioned.
Q ^b1 and Q ^b2 are each independently preferably a fluorine atom or a trifluoromethyl group, and more preferably both are fluorine atoms.
The divalent saturated hydrocarbon group for L ^b1 includes a linear alkanediyl group, a branched alkanediyl group, and a monocyclic or polycyclic bivalent alicyclic saturated hydrocarbon group. A group formed by combining two or more of the groups may also be used.
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, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group , tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group and heptadecane-1,17-diyl group. alkanediyl 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, and 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; alicyclic saturated hydrocarbon group;
Polycyclic bivalent 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 and the like.
Groups in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ^b1 is replaced with —O— or —CO— include, for example, formulas (b1-1) to (b1-3) The group represented by any one of is mentioned. In addition, in the groups represented by formulas (b1-1) to (b1-3) and the groups represented by formulas (b1-4) to (b1-11) which are specific examples thereof, * and * * represents a binding site, and * represents a bond with -Y.

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

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

In the groups represented by formulas (b1-1) to (b1-3), when —CH ₂ — contained in the saturated hydrocarbon group is replaced with —O— or —CO—, carbon before replacement Let the number be the number of carbon atoms of the saturated hydrocarbon group.
As the divalent saturated hydrocarbon group, the same divalent saturated hydrocarbon group as L ^b1 can be mentioned.

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

［式（ｂ１－４）中、
Ｌ^b8は、単結合又は炭素数１～２２の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
式（ｂ１－５）中、
Ｌ^b9は、炭素数１～２０の２価の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる－ＣＨ_２－は－Ｏ－又は－ＣＯ－に置き換わっていてもよい。
Ｌ^b10は、単結合又は炭素数１～１９の２価の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b9及びＬ^b10の合計炭素数は２０以下である。
式（ｂ１－６）中、
Ｌ^b11は、炭素数１～２１の２価の飽和炭化水素基を表す。
Ｌ^b12は、単結合又は炭素数１～２０の２価の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b11及びＬ^b12の合計炭素数は２１以下である。
式（ｂ１－７）中、
Ｌ^b13は、炭素数１～１９の２価の飽和炭化水素基を表す。
Ｌ^b14は、単結合又は炭素数１～１８の２価の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる－ＣＨ_２－は－Ｏ－又は－ＣＯ－に置き換わっていてもよい。
Ｌ^b15は、単結合又は炭素数１～１８の２価の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b13～Ｌ^b15の合計炭素数は１９以下である。
式（ｂ１－８）中、
Ｌ^b16は、炭素数１～１８の２価の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる－ＣＨ_２－は－Ｏ－又は－ＣＯ－に置き換わっていてもよい。
Ｌ^b17は、炭素数１～１８の２価の飽和炭化水素基を表す。
Ｌ^b18は、単結合又は炭素数１～１７の２価の飽和炭化水素基を表し、該２価の飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b16～Ｌ^b18の合計炭素数は１９以下である。］ The group in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ^b1 is replaced with —O— or —CO— is represented by formula (b1-1) or formula (b1-3). are preferred.
Examples of the group represented by formula (b1-1) include groups represented by formulas (b1-4) to (b1-8).

[In formula (b1-4),
L ^b8 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
In formula (b1-5),
L ^b9 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced with —O— or —CO—.
L ^b10 represents a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. .
However, the total carbon number of L ^b9 and L ^b10 is 20 or less.
In formula (b1-6),
L ^b11 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b12 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. .
However, the total carbon number of L ^b11 and L ^b12 is 21 or less.
In formula (b1-7),
L ^b13 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.
L ^b14 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group is replaced with —O— or —CO— good too.
L ^b15 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. .
However, the total carbon number of L ^b13 to L ^b15 is 19 or less.
In formula (b1-8),
L ^b16 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced with —O— or —CO—.
L ^b17 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b18 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. .
However, the total carbon number of L ^b16 to L ^b18 is 19 or less. ]

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

式（ｂ１－９）中、
Ｌ^b19は、単結合又は炭素数１～２３の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b20は、単結合又は炭素数１～２３の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子、ヒドロキシ基又はアルキルカルボニルオキシ基に置換されていてもよい。該アルキルカルボニルオキシ基に含まれる－ＣＨ₂－は、－Ｏ－又は－ＣＯ－に置き換わっていてもよく、該アルキルカルボニルオキシ基に含まれる水素原子は、ヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b19及びＬ^b20の合計炭素数は２３以下である。
式（ｂ１－１０）中、
Ｌ^b21は、単結合又は炭素数１～２１の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b22は、単結合又は炭素数１～２１の２価の飽和炭化水素基を表す。
Ｌ^b23は、単結合又は炭素数１～２１の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子、ヒドロキシ基又はアルキルカルボニルオキシ基に置換されていてもよい。該アルキルカルボニルオキシ基に含まれる－ＣＨ₂－は、－Ｏ－又は－ＣＯ－に置き換わっていてもよく、該アルキルカルボニルオキシ基に含まれる水素原子は、ヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b21、Ｌ^b22及びＬ^b23の合計炭素数は２１以下である。
式（ｂ１－１１）中、
Ｌ^b24は、単結合又は炭素数１～２０の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b25は、炭素数１～２１の２価の飽和炭化水素基を表す。
Ｌ^b26は、単結合又は炭素数１～２０の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子、ヒドロキシ基又はアルキルカルボニルオキシ基に置換されていてもよい。該アルキルカルボニルオキシ基に含まれる－ＣＨ₂－は、－Ｏ－又は－ＣＯ－に置き換わっていてもよく、該アルキルカルボニルオキシ基に含まれる水素原子は、ヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b24、Ｌ^b25及びＬ^b26の合計炭素数は２１以下である。
なお、式（ｂ１－９）で表される基から式（ｂ１－１１）で表される基においては、飽和炭化水素基に含まれる水素原子がアルキルカルボニルオキシ基に置換されている場合、置き換わる前の炭素数を該飽和炭化水素基の炭素数とする。 Examples of the group represented by formula (b1-3) include groups represented by formulas (b1-9) to (b1-11).

In formula (b1-9),
L ^b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b20 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, a hydrogen atom contained in the saturated hydrocarbon group being substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group; good too. --CH ₂ -- contained in the alkylcarbonyloxy group may be replaced with --O-- or --CO--, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxy group.
However, the total carbon number of L ^b19 and L ^b20 is 23 or less.
In formula (b1-10),
L ^b21 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b22 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b23 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group; good too. --CH ₂ -- contained in the alkylcarbonyloxy group may be replaced with --O-- or --CO--, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxy group.
However, the total carbon number of L ^b21 , L ^b22 and L ^b23 is 21 or less.
In formula (b1-11),
L ^b24 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b25 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b26 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group; good too. --CH ₂ -- contained in the alkylcarbonyloxy group may be replaced with --O-- or --CO--, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxy group.
However, the total carbon number of L ^b24 , L ^b25 and L ^b26 is 21 or less.
In addition, in the group represented by formula (b1-9) to the group represented by formula (b1-11), when the hydrogen atom contained in the saturated hydrocarbon group is substituted with an alkylcarbonyloxy group, it is replaced Let the previous carbon number be the carbon number of this saturated hydrocarbon group.

The alkylcarbonyloxy group includes an acetyloxy group, a propionyloxy group, a butyryloxy group, a cyclohexylcarbonyloxy group, an adamantylcarbonyloxy group and the like.

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

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

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

Examples of the group represented by formula (b1-7) include the following.

Examples of the group represented by formula (b1-8) include the following.

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

Examples of the group represented by formula (b1-9) include the following.

Examples of the group represented by formula (b1-10) include the following.

Examples of the group represented by formula (b1-11) include the following.

The alicyclic hydrocarbon group represented by Y includes groups represented by formulas (Y1) to (Y11) and formulas (Y36) to (Y38).
When —CH ₂ — contained in the alicyclic hydrocarbon group represented by Y is replaced with —O—, —S(O) ₂ — or —CO—, the number may be 1 or 2 or more. good. Such groups include groups represented by formulas (Y12) to (Y35) and formulas (Y39) to (Y41).

Ｙで表される脂環式炭化水素基としては、好ましくは式（Ｙ１）～式（Ｙ２０）、式（Ｙ２６）、式（Ｙ２７）、式（Ｙ３０）、式（Ｙ３１）、式（Ｙ３９）～式（Ｙ４１）のいずれかで表される基であり、より好ましくは式（Ｙ１１）、式（Ｙ１５）、式（Ｙ１６）、式（Ｙ２０）、式（Ｙ２６）、式（Ｙ２７）、式（Ｙ３０）、式（Ｙ３１）、式（Ｙ３９）又は式（Ｙ４０）で表される基であり、さらに好ましくは式（Ｙ１１）、式（Ｙ１５）、式（Ｙ２０）、式（Ｙ２６）、式（Ｙ２７）、式（Ｙ３０）、式（Ｙ３１）、式（Ｙ３９）又は式（Ｙ４０）で表される基である。
Ｙで表される脂環式炭化水素基が式（Ｙ２８）～式（Ｙ３５）、式（Ｙ３９）～式（Ｙ４０）等のスピロ環である場合には、２つの酸素原子間のアルカンジイル基は、１以上のフッ素原子を有することが好ましい。また、ケタール構造に含まれるアルカンジイル基のうち、酸素原子に隣接するメチレン基には、フッ素原子が置換されていないのが好ましい。

The alicyclic hydrocarbon group represented by Y is preferably represented by formulas (Y1) to (Y20), formula (Y26), formula (Y27), formula (Y30), formula (Y31), and formula (Y39). to a group represented by any one of formula (Y41), more preferably formula (Y11), formula (Y15), formula (Y16), formula (Y20), formula (Y26), formula (Y27), formula (Y30), a group represented by formula (Y31), formula (Y39) or formula (Y40), more preferably formula (Y11), formula (Y15), formula (Y20), formula (Y26) or formula (Y27), a group represented by formula (Y30), formula (Y31), formula (Y39) or formula (Y40).
When the alicyclic hydrocarbon group represented by Y is a spiro ring such as formulas (Y28) to (Y35) and formulas (Y39) to (Y40), an alkanediyl group between two oxygen atoms preferably has one or more fluorine atoms. Further, among the alkanediyl groups contained in the ketal structure, the methylene group adjacent to the oxygen atom is preferably not substituted with a fluorine atom.

Examples of substituents of the methyl group represented by Y include a halogen atom, a hydroxy group, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, a glycidyloxy group, -( CH ₂ ) _ja —CO—O—R ^b1 group or —(CH ₂ ) _ja —O—CO—R ^b1 group (wherein R ^b1 is a C 1-16 alkyl group, a C 3-16 represents an alicyclic hydrocarbon group, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group combining these, ja represents an integer of 0 to 4. an alkyl group having 1 to 16 carbon atoms, and -CH ₂ - contained in an alicyclic hydrocarbon group having 3 to 16 carbon atoms may be replaced with -O-, -S(O) ₂ - or -CO-).
Substituents for the alicyclic hydrocarbon group represented by Y include a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms optionally substituted by a hydroxy group, and an alicyclic group having 3 to 16 carbon atoms. hydrocarbon group, alkoxy group having 1 to 12 carbon atoms, aromatic hydrocarbon group having 6 to 18 carbon atoms, aralkyl group having 7 to 21 carbon atoms, alkylcarbonyl group having 2 to 4 carbon atoms, glycidyloxy group, -( CH ₂ ) _ja —CO—O—R ^b1 group or —(CH ₂ ) _ja —O—CO—R ^b1 group (wherein R ^b1 is a C 1-16 alkyl group, a C 3-16 represents an alicyclic hydrocarbon group, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group combining these, ja represents an integer of 0 to 4. an alkyl group having 1 to 16 carbon atoms, and -CH ₂ - contained in an alicyclic hydrocarbon group having 3 to 16 carbon atoms may be replaced with -O-, -S(O) ₂ - or -CO-).
Halogen atoms include fluorine, chlorine, bromine and iodine atoms.
Examples of alicyclic hydrocarbon groups include cyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, cycloheptyl, cyclooctyl, norbornyl and adamantyl groups.
Examples of aromatic hydrocarbon groups include aryl groups such as phenyl, naphthyl, anthryl, biphenyl, and phenanthryl groups. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group, and an aromatic hydrocarbon group having a chain hydrocarbon group having 1 to 18 carbon atoms (tolyl group, xylyl group, cumenyl group, mesityl group, p-ethylphenyl group, p-tert-butylphenyl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.), and lipids having 3 to 18 carbon atoms. Examples thereof include aromatic hydrocarbon groups having a cyclic hydrocarbon group (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.).
Examples of alkyl groups include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group and nonyl. group, decyl group, undecyl group, dodecyl group and the like.
Alkyl groups substituted with a hydroxy group include hydroxyalkyl groups such as a hydroxymethyl group and a hydroxyethyl group.
Alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy and dodecyloxy groups.
Aralkyl groups include benzyl, phenethyl, phenylpropyl, naphthylmethyl and naphthylethyl groups.
Examples of alkylcarbonyl groups include acetyl group, propionyl group and butyryl group.

Examples of Y include the following.

Y is preferably an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, more preferably an optionally substituted adamantyl group, and the alicyclic carbonization —CH ₂ — constituting a hydrogen group or an adamantyl group may be replaced with —CO—, —S(O) ₂ — or —CO—. Y is more preferably an adamantyl group, a hydroxyadamantyl group, an oxoadamantyl group, or a group represented below.

Examples of the anion in the acid generator (B1) include anions represented by formulas (B1-A-1) to (B1-A-55) [hereinafter referred to as "anion (B1-A-1) etc. ] is preferable, formula (B1-A-1) ~ formula (B1-A-4), formula (B1-A-9), formula (B1-A-10), formula (B1-A-24) ~ formula (B1-A-33), represented by formula (B1-A-36) ~ formula (B1-A-40), formula (B1-A-47) ~ formula (B1-A-55) Anions are more preferred.

ここでＲⁱ²～Ｒⁱ⁷は、互いに独立に、例えば、炭素数１～４のアルキル基、好ましくはメチル基又はエチル基である。Ｒⁱ⁸は、例えば、炭素数１～１２の脂肪族炭化水素基、好ましくは炭素数１～４のアルキル基、炭素数５～１２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、より好ましくはメチル基、エチル基、シクロヘキシル基又はアダマンチル基である。Ｌ^A4は、単結合又は炭素数１～４のアルカンジイル基である。
Ｑ^b1及びＱ^b2は、上記と同じ意味を表す。
酸発生剤（Ｂ１）におけるアニオンとしては、具体的には、特開２０１０－２０４６４６号公報に記載されたアニオンが挙げられる。

Here, R ⁱ² to R ⁱ⁷ are each independently, for example, an alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group. R ⁱ⁸ is, for example, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 5 to 12 carbon atoms, or a combination thereof. group, more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group. L ^A4 is a single bond or an alkanediyl group having 1 to 4 carbon atoms.
Q ^b1 and Q ^b2 have the same meaning as above.
Specific examples of the anion in the acid generator (B1) include anions described in JP-A-2010-204646.

Preferred anions in the acid generator (B1) include anions represented by formulas (B1a-1) to (B1a-34).

Among them, formula (B1a-1) ~ formula (B1a-3) and formula (B1a-7) ~ formula (B1a-16), formula (B1a-18), formula (B1a-19), formula (B1a-22 ) to Formula (B1a-30) are preferred.

Organic cations of Z ⁺ include organic onium cations, organic sulfonium cations, organic iodonium cations, organic ammonium cations, benzothiazolium cations, organic phosphonium cations, and the like. Among these, organic sulfonium cations and organic iodonium cations are preferred, and arylsulfonium cations are more preferred. Specifically, a cation represented by any one of formulas (b2-1) to (b2-4) (hereinafter sometimes referred to as "cation (b2-1)" etc. depending on the formula number) is mentioned.

式（ｂ２－１）～式（ｂ２－４）において、
Ｒ^b4～Ｒ^b6は、それぞれ独立に、炭素数１～３０の鎖式炭化水素基、炭素数３～３６の脂環式炭化水素基又は炭素数６～３６の芳香族炭化水素基を表し、該鎖式炭化水素基に含まれる水素原子は、ヒドロキシ基、炭素数１～１２のアルコキシ基、炭素数３～１２の脂環式炭化水素基又は炭素数６～１８の芳香族炭化水素基で置換されていてもよく、該脂環式炭化水素基に含まれる水素原子は、ハロゲン原子、炭素数１～１８の脂肪族炭化水素基、炭素数２～４のアルキルカルボニル基又はグリシジルオキシ基で置換されていてもよく、該芳香族炭化水素基に含まれる水素原子は、ハロゲン原子、ヒドロキシ基又は炭素数１～１２のアルコキシ基で置換されていてもよい。
Ｒ^b4とＲ^b5とは、互いに結合してそれらが結合する硫黄原子と一緒になって環を形成してもよく、該環に含まれる－ＣＨ₂－は、－Ｏ－、－Ｓ－又は－ＣＯ－に置き換わってもよい。
Ｒ^b7及びＲ^b8は、それぞれ独立に、ヒドロキシ基、炭素数１～１２の脂肪族炭化水素基又は炭素数１～１２のアルコキシ基を表す。
ｍ２及びｎ２は、それぞれ独立に０～５のいずれかの整数を表す。
ｍ２が２以上のとき、複数のＲ^b7は同一でも異なってもよく、ｎ２が２以上のとき、複数のＲ^b8は同一でも異なってもよい。
Ｒ^b9及びＲ^b10は、それぞれ独立に、炭素数１～３６の鎖式炭化水素基又は炭素数３～３６の脂環式炭化水素基を表す。
Ｒ^b9とＲ^b10とは、互いに結合してそれらが結合する硫黄原子と一緒になって環を形成してもよく、該環に含まれる－ＣＨ₂－は、－Ｏ－、－Ｓ－又は－ＣＯ－に置き換わってもよい。
Ｒ^b11は、水素原子、炭素数１～３６の鎖式炭化水素基、炭素数３～３６の脂環式炭化水素基又は炭素数６～１８の芳香族炭化水素基を表す。
Ｒ^b12は、炭素数１～１２の鎖式炭化水素基、炭素数３～１８の脂環式炭化水素基又は炭素数６～１８の芳香族炭化水素基を表し、該鎖式炭化水素に含まれる水素原子は、炭素数６～１８の芳香族炭化水素基で置換されていてもよく、該芳香族炭化水素基に含まれる水素原子は、炭素数１～１２のアルコキシ基又は炭素数１～１２のアルキルカルボニルオキシ基で置換されていてもよい。
Ｒ^b11とＲ^b12とは、互いに結合してそれらが結合する－ＣＨ－ＣＯ－を含めて環を形成していてもよく、該環に含まれる－ＣＨ₂－は、－Ｏ－、－Ｓ－又は－ＣＯ－に置き換わってもよい。
Ｒ^b13～Ｒ^b18は、それぞれ独立に、ヒドロキシ基、炭素数１～１２の脂肪族炭化水素基又は炭素数１～１２のアルコキシ基を表す。
Ｌ^b31は、硫黄原子又は酸素原子を表す。
ｏ２、ｐ２、ｓ２、及びｔ２は、それぞれ独立に、０～５のいずれかの整数を表す。
ｑ２及びｒ２は、それぞれ独立に、０～４のいずれかの整数を表す。
ｕ２は０又は１を表す。
ｏ２が２以上のとき、複数のＲ^b13は同一又は相異なり、ｐ２が２以上のとき、複数のＲ^b14は同一又は相異なり、ｑ２が２以上のとき、複数のＲ^b15は同一又は相異なり、ｒ２が２以上のとき、複数のＲ^b16は同一又は相異なり、ｓ２が２以上のとき、複数のＲ^b17は同一又は相異なり、ｔ２が２以上のとき、複数のＲ^b18は同一又は相異なる。
脂肪族炭化水素基とは、鎖式炭化水素基及び脂環式炭化水素基を表す。
鎖式炭化水素基としては、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、ｓｅｃ－ブチル基、ｔｅｒｔ－ブチル基、ペンチル基、ヘキシル基、オクチル基及び２－エチルヘキシル基のアルキル基が挙げられる。
特に、Ｒ^b9～Ｒ^b12の鎖式炭化水素基は、好ましくは炭素数１～１２である。
脂環式炭化水素基としては、単環式又は多環式のいずれでもよく、単環式の脂環式炭化水素基としては、シクロプロピル基、シクロブチル基、シクロペンチル基、シクロへキシル基、シクロヘプチル基、シクロオクチル基、シクロデシル基等のシクロアルキル基が挙げられる。多環式の脂環式炭化水素基としては、デカヒドロナフチル基、アダマンチル基、ノルボルニル基及び下記の基等が挙げられる。

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。
水素原子が脂肪族炭化水素基で置換された脂環式炭化水素基としては、メチルシクロヘキシル基、ジメチルシクロへキシル基、２－メチルアダマンタン－２－イル基、２－エチルアダマンタン－２－イル基、２－イソプロピルアダマンタン－２－イル基、メチルノルボルニル基、イソボルニル基等が挙げられる。水素原子が脂肪族炭化水素基で置換された脂環式炭化水素基においては、脂環式炭化水素基と脂肪族炭化水素基との合計炭素数が好ましくは２０以下である。
芳香族炭化水素基としては、フェニル基、ビフェニル基、ナフチル基、フェナントリル基等のアリール基等が挙げられる。芳香族炭化水素基は、鎖式炭化水素基又は脂環式炭化水素基を有していてもよく、鎖式炭化水素基を有する芳香族炭化水素基（トリル基、キシリル基、クメニル基、メシチル基、ｐ－エチルフェニル基、ｐ－ｔｅｒｔ－ブチルフェニル基、２，６－ジエチルフェニル基、２－メチル－６－エチルフェニル基等）及び脂環式炭化水素基を有する芳香族炭化水素基（ｐ－シクロへキシルフェニル基、ｐ－アダマンチルフェニル基等）等が挙げられる。
なお、芳香族炭化水素基に、鎖式炭化水素基又は脂環式炭化水素基が含まれる場合は、炭素数１～１８の鎖式炭化水素基及び炭素数３～１８の脂環式炭化水素基が好ましい。
水素原子がアルコキシ基で置換された芳香族炭化水素基としては、ｐ－メトキシフェニル基等が挙げられる。
水素原子が芳香族炭化水素基で置換された鎖式炭化水素基としては、ベンジル基、フェネチル基、フェニルプロピル基、トリチル基、ナフチルメチル基、ナフチルエチル基等のアラルキル基が挙げられる。

In formulas (b2-1) to (b2-4),
R ^b4 to R ^b6 each independently represent a chain 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 chain 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 a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, or a glycidyloxy group. It may be substituted, and a 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 bonded to each other to form a ring together with the sulfur atom to which they are bonded, and —CH ₂ — contained in the ring may be —O—, —S— or -CO- may be substituted.
R ^b7 and R ^b8 each 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, multiple R ^b7 may be the same or different, and when n2 is 2 or more, multiple R ^b8 may be the same or different.
R ^b9 and R ^b10 each independently represent a chain 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 bonded to each other to form a ring together with the sulfur atom to which they are bonded, and —CH ₂ — contained in the ring may be —O—, —S— or -CO- may be substituted.
R ^b11 represents a hydrogen atom, a chain 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 a chain 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 may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atoms contained in the aromatic hydrocarbon group are alkoxy groups having 1 to 12 carbon atoms or 1 to 1 carbon atoms. It may be substituted with 12 alkylcarbonyloxy groups.
R ^b11 and R ^b12 may be bonded to each other to form a ring including —CH—CO— to which they are bonded, and —CH ₂ — contained in the ring may be —O—, —S - or -CO- may be substituted.
R ^b13 to R ^b18 each 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 to 5;
q2 and r2 each independently represent an integer of 0 to 4;
u2 represents 0 or 1;
When o2 is 2 or more, multiple R ^b13 are the same or different, when p2 is 2 or more, multiple R ^b14 are the same or different, and when q2 is 2 or more, multiple R ^b15 are the same or different. , when r2 is 2 or more, the plurality of R ^b16 are the same or different; when s2 is 2 or more, the plurality of R ^b17 are the same or different; when t2 is 2 or more, the plurality of R ^b18 are the same or different; different.
An aliphatic hydrocarbon group represents a chain hydrocarbon group and an alicyclic hydrocarbon group.
Chain hydrocarbon groups include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group and 2-ethylhexyl group. mentioned.
In particular, chain 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, a cyclo Cycloalkyl groups such as a heptyl group, a cyclooctyl group, and a cyclodecyl group can be mentioned. The polycyclic alicyclic hydrocarbon group includes decahydronaphthyl group, adamantyl group, 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, more preferably 4 to 12 carbon atoms.
Alicyclic hydrocarbon groups in which hydrogen atoms are substituted with aliphatic hydrocarbon groups include methylcyclohexyl group, dimethylcyclohexyl group, 2-methyladamantan-2-yl group, and 2-ethyladamantan-2-yl group. , 2-isopropyladamantan-2-yl group, methylnorbornyl group, isobornyl group and the like. In the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group, the total carbon number of the alicyclic hydrocarbon group and the aliphatic hydrocarbon group is preferably 20 or less.
Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, biphenyl group, naphthyl group and phenanthryl group. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group, and aromatic hydrocarbon groups having chain hydrocarbon groups (tolyl, xylyl, cumenyl, mesityl group, p-ethylphenyl group, p-tert-butylphenyl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.) and an aromatic hydrocarbon group having an alicyclic hydrocarbon group ( p-cyclohexylphenyl group, p-adamantylphenyl group, etc.) and the like.
When the aromatic hydrocarbon group contains a chain hydrocarbon group or an alicyclic hydrocarbon group, a chain hydrocarbon group having 1 to 18 carbon atoms and an alicyclic hydrocarbon group having 3 to 18 carbon atoms groups are preferred.
Aromatic hydrocarbon groups in which a hydrogen atom is substituted with an alkoxy group include a p-methoxyphenyl group and the like.
Chain hydrocarbon groups in which hydrogen atoms are substituted with aromatic hydrocarbon groups include aralkyl groups such as benzyl, phenethyl, phenylpropyl, trityl, naphthylmethyl and naphthylethyl groups.

Alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy and dodecyloxy groups.
An acetyl group, a propionyl group, a butyryl group, etc. are mentioned as an alkylcarbonyl group.
Halogen atoms include fluorine, chlorine, bromine and iodine atoms.
The alkylcarbonyloxy group includes a methylcarbonyloxy group, an ethylcarbonyloxy group, a propylcarbonyloxy group, an isopropylcarbonyloxy group, a butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group and a pentylcarbonyloxy group. , hexylcarbonyloxy group, octylcarbonyloxy group and 2-ethylhexylcarbonyloxy group.
The ring formed by R ^b4 and R ^b5 bonded together with the sulfur atom to which they are bonded may be monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated. may be a ring of This ring includes a ring having 3 to 18 carbon atoms, preferably a ring having 4 to 18 carbon atoms. Further, the ring containing a sulfur atom includes a 3- to 12-membered ring, preferably a 3- to 7-membered ring, and examples thereof include the following rings. * represents a binding site.

The ring formed by R ^b9 and R ^b10 together may be a monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated ring. This ring includes a 3- to 12-membered ring, preferably a 3- to 7-membered ring. Examples include thiolan-1-ium ring (tetrahydrothiophenium ring), thian-1-ium ring, 1,4-oxathian-4-ium ring and the like.
The ring formed by R ^b11 and R ^b12 together may be a monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated ring. This ring includes a 3- to 12-membered ring, preferably a 3- to 7-membered ring. oxocycloheptane ring, oxocyclohexane ring, oxonorbornane ring, oxoadamantane ring and the like.

Among the cations (b2-1) to (b2-4), the cation (b2-1) is preferred.
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 acid generator (B) is a combination of the aforementioned anions and the aforementioned organic cations, and these can be combined arbitrarily. As the acid generator (B), preferably formulas (B1a-1) to (B1a-3) and formulas (B1a-7) to (B1a-16), formulas (B1a-18), and formulas (B1a- 19), a combination of an anion represented by any one of formulas (B1a-22) to (B1a-34) and a cation (b2-1) or a cation (b2-3).

The acid generator (B) preferably includes those represented by formulas (B1-1) to (B1-48), respectively. Among them, those containing an arylsulfonium cation are preferred, and formula (B1-1) ~ Formula (B1-3), Formula (B1-5) ~ Formula (B1-7), Formula (B1-11) ~ Formula (B1-14), Formula (B1-20) ~ Formula (B1-26), Those represented by formula (B1-29) and formulas (B1-31) to (B1-48) are particularly preferred.

In the resist composition of the present invention, the content of the acid generator is preferably 1 part by mass or more and 40 parts by mass or less, more preferably 3 parts by mass or more and 35 parts by mass or less, relative to 100 parts by mass of the resin (A). and more preferably 10 parts by mass or more and 35 parts by mass or less. The resist composition of the present invention may contain one type of acid generator (B) alone, or may contain a plurality of types.

<Solvent (E)>
The content of the solvent (E) in the resist composition is usually 90% by mass or more and 99.9% by mass or less, preferably 92% by mass or more and 99% by mass or less, more preferably 94% by mass or more and 99% by mass. % or less. The content of the solvent (E) can be measured by 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; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; One kind of the solvent (E) may be used alone, or two or more kinds may be used.

<Quencher (C)>
Examples of the quencher (C) include salts that generate an acid weaker in acidity than the acid generated from the acid generator (B), and basic nitrogen-containing organic compounds. The content of the quencher (C) is preferably about 0.01 to 5% by mass, more preferably about 0.01 to 3% by mass, based on the solid content of the resist composition.

<Salt that generates an acid with a weaker acidity than the acid generated from the acid generator>
The acidity of a salt that generates an acid weaker than the acid generated from the acid generator (B) is indicated by the acid dissociation constant (pKa). The salt that generates an acid weaker in acidity than the acid generated from the acid generator (B) has an acid dissociation constant of -3<pKa, preferably -1<. Salts with pKa<7, more preferably salts with 0<pKa<5.
Examples of the salt that generates an acid weaker in acidity than the acid generated from the acid generator (B) include salts represented by the following formula, and salts represented by the formula (D) described in JP-A-2015-147926. (Hereinafter, it may be referred to as "weak acid inner salt (D)".), and JP-A-2012-229206, JP-A-2012-6908, JP-A-2012-72109, JP-A-2011-39502. and salts described in JP-A-2011-191745. The salt that generates an acid weaker in acidity than the acid generated from the acid generator (B) is preferably a weak acid inner salt (D).

The weak acid inner salt (D) includes the following salts.

Basic nitrogen-containing organic compounds include amines and ammonium salts. Amines include aliphatic amines and aromatic amines. Aliphatic amines include primary, secondary and tertiary amines.
Amines include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N,N-dimethylaniline, diphenylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, tri heptylamine, 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, tri isopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3 , 3′-diethyldiphenylmethane, 2,2′-methylenebisaniline, 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′-dipyridylamine, 2,2′-dipicolylamine, bipyridine and the like, Aromatic amines such as diisopropylaniline are preferred, and 2,6-diisopropylaniline is more preferred.
Ammonium salts include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3-(trifluoromethyl)phenyltrimethyl ammonium hydroxide, tetra-n-butylammonium salicylate and choline;

<Other ingredients>
If necessary, the resist composition of the present invention may contain components other than the components described above (hereinafter sometimes referred to as "other components (F)"). Other components (F) are not particularly limited, and additives known in the field of resists, such as sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes, etc., can be used.

<Preparation of resist composition>
The resist composition of the present invention comprises the resin (A) of the present invention, the acid generator (B), a salt that generates an acid with a weaker acidity than the acid generated from the acid generator, and, if necessary, a resin It can be prepared by mixing (A2), resin (X), quencher (C), solvent (E) and other components (F). The mixing order is arbitrary and not particularly limited. The temperature during mixing can be appropriately selected from 10 to 40° C. depending on the type of resin and the solubility of the resin in the solvent (E). An appropriate mixing time can be selected from 0.5 to 24 hours depending on the mixing temperature. The mixing means is also not particularly limited, and stirring and mixing 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.

<Method for manufacturing resist pattern>
The method for producing a resist pattern of the present invention comprises:
(1) a step of applying the resist composition of the present invention onto a substrate;
(2) a step of drying the applied composition to form a composition layer;
(3) exposing the composition layer;
(4) heating the exposed composition layer; and (5) developing the heated composition layer.
The coating of the resist composition on the substrate can be carried out using a commonly used device such as a spin coater. Examples of substrates include inorganic substrates such as silicon wafers. Before applying the resist composition, the substrate may be washed, and an antireflection film or the like may be formed on the substrate.
By drying the applied composition, the solvent is removed and a composition layer is formed. Drying is carried out, for example, by evaporating the solvent using a heating device such as a hot plate (so-called pre-baking), 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. Moreover, the pressure for drying under reduced pressure is preferably about 1 to 1.0×10 ⁵ Pa.
The resulting composition layer is usually exposed using an exposure machine. The exposure machine may be an immersion exposure machine. As the exposure light source, a KrF excimer laser (wavelength: 248 nm), an ArF excimer laser (wavelength: 193 nm), an _F2 excimer laser (wavelength: 157 nm) that emits a laser beam in the ultraviolet region, a solid-state laser source (YAG or semiconductor laser etc.) and emits harmonic laser light in the far ultraviolet region or vacuum ultraviolet region by wavelength conversion, electron beam, extreme ultraviolet light (EUV), etc. can be done. In the present specification, these irradiations with radiation may be collectively referred to as "exposure". During exposure, exposure is usually performed through a mask corresponding to the desired pattern. When the exposure light source is an electron beam, exposure may be performed by direct drawing without using a mask.
The exposed composition layer is subjected to a heat treatment (so-called post-exposure bake) in order to promote the deprotection reaction at the acid-labile groups. 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 developer using a developing device. The developing method includes a dipping method, a paddle method, a spraying method, a dynamic dispensing method, and the like. The development temperature is preferably, for example, 5 to 60° C., and the development time is preferably, for example, 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 the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer may be any of various alkaline aqueous solutions used in this field. Examples thereof include aqueous solutions of tetramethylammonium hydroxide and (2-hydroxyethyl)trimethylammonium hydroxide (commonly known as choline). The alkaline developer may contain a surfactant.
It is preferable to wash the resist pattern with ultrapure water after development, and then remove water remaining on the substrate and pattern.
When producing a negative resist pattern from the resist composition of the present invention, a developer containing an organic solvent (hereinafter sometimes referred to as "organic developer") is used as the developer.
Examples of organic solvents contained in the organic developer include ketone solvents such as 2-hexanone and 2-heptanone; glycol ether ester solvents such as propylene glycol monomethyl ether acetate; ester solvents such as butyl acetate; glycols such as propylene glycol monomethyl ether. ether solvents; amide solvents such as N,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 still more preferably substantially only the organic solvent.
Among them, 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 contains butyl acetate and/or 2-heptanone. - more preferably only heptanone.
The organic developer may contain a surfactant. In addition, the organic developer may contain a very small amount of water.
During development, the development may be stopped by replacing the organic developer with a solvent of a different type.
It is preferable to wash the resist pattern after development with a rinsing liquid. The rinse 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, preferably an alcohol solvent or an ester solvent.
After cleaning, it is preferable to remove the rinse liquid remaining on the substrate and pattern.

<Application>
The resist composition of the present invention is suitable as 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. It is more suitable as a resist composition for electron beam (EB) exposure or as a resist composition for EUV exposure, and is useful for microfabrication of semiconductors.

EXAMPLES The present invention will be described more specifically with reference to examples. In the examples, "%" and "parts" representing the content or amount used are based on mass unless otherwise specified.
The weight average molecular weight is a value obtained by gel permeation chromatography under the following conditions.
Apparatus: HLC-8120GPC type (manufactured by Tosoh Corporation)
Column: TSKgel Multipore H _XL -M x 3 + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL/min
Detector: RI detector Column temperature: 40°C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)
Further, the structure of the compound was confirmed by measuring the molecular ion peak using mass spectrometry (LC: Agilent Model 1100, MASS: Agilent Model LC/MSD). In the following examples, the value of this molecular ion peak is indicated by "MASS".

以下、これらのモノマーを式番号に応じて「モノマー（ａ１－１－３）」等という。 Synthesis of Resin The compounds (monomers) used in synthesizing the resin are shown below.

Hereinafter, these monomers are referred to as "monomer (a1-1-3)" and the like according to their formula numbers.

Example 1 [Synthesis of Resin A1]
As monomers, acetoxystyrene, monomer (a1-1-3), monomer (a1-2-6) and monomer (I-1) are used, and the molar ratio [acetoxystyrene:monomer (a1-1-3): Monomer (a1-2-6): Monomer (I-1)] is mixed so that the ratio is 38:24:28:10, and further, to this monomer mixture, 1.5 times by mass of methyl isobutyl ketone was mixed. To the obtained mixture, azobisisobutyronitrile was added as an initiator so as to be 7 mol % with respect to the total number of moles of all monomers, and the mixture was heated at 85° C. for about 5 hours to carry out polymerization. rice field. Thereafter, a 25% tetramethylammonium hydroxide aqueous solution was added to the polymerization reaction solution, stirred for 12 hours, and then separated. The obtained organic layer is poured into a large amount of n-heptane to precipitate the resin, which is then filtered and collected to obtain a resin A1 (copolymer) having a weight average molecular weight of about 5.4×10 ³ with a yield of 66. obtained in %. This resin A1 has the following structural units.

Example 2 [Synthesis of Resin A2]
As monomers, acetoxystyrene, monomer (a1-1-3), monomer (a1-2-6) and monomer (I-2) were used, and the molar ratio [acetoxystyrene:monomer (a1-1-3): Monomer (a1-2-6): Monomer (I-2)] is mixed in a ratio of 38:24:28:10, and further, to this monomer mixture, 1.5 times by mass of methyl isobutyl ketone was mixed. To the obtained mixture, azobisisobutyronitrile was added as an initiator so as to be 7 mol % with respect to the total number of moles of all monomers, and the mixture was heated at 85° C. for about 5 hours to carry out polymerization. rice field. Thereafter, a 25% tetramethylammonium hydroxide aqueous solution was added to the polymerization reaction solution, stirred for 12 hours, and then separated. The resulting organic layer was poured into a large amount of n-heptane to precipitate the resin, which was then filtered and collected to yield 61% of resin A2 (copolymer) having a weight average molecular weight of about 5.8×10 ³ . obtained in %. This resin A2 has the following structural units.

Example 3 [Synthesis of Resin A3]
As monomers, acetoxystyrene, monomer (a1-1-3) and monomer (I-1) are used, and the molar ratio [acetoxystyrene:monomer (a1-1-3):monomer (I-1)] is They were mixed in a ratio of 38:24:38, and methyl isobutyl ketone was added to the monomer mixture in an amount of 1.5 times the mass of the total mass of all the monomers. To the obtained mixture, azobisisobutyronitrile was added as an initiator so as to be 7 mol % with respect to the total number of moles of all monomers, and the mixture was heated at 85° C. for about 5 hours to carry out polymerization. rice field. Thereafter, a 25% tetramethylammonium hydroxide aqueous solution was added to the polymerization reaction solution, stirred for 12 hours, and then separated. The obtained organic layer was poured into a large amount of n-heptane to precipitate the resin, which was then filtered and collected to obtain a resin A3 (copolymer) having a weight average molecular weight of about 5.7×10 ³ with a yield of 59. obtained in %. This resin A3 has the following structural units.

Example 4 [Synthesis of Resin A4]
As monomers, monomer (a2-2-1), monomer (a1-1-3) and monomer (I-1) are used, and the molar ratio [monomer (a2-2-1):monomer (a1-1-3 ):monomer (I-1)] are mixed in a ratio of 38:24:38, and to this monomer mixture, methyl isobutyl ketone is added in an amount 1.5 times the weight of the total weight of all the monomers. were mixed. To the obtained mixture, azobisisobutyronitrile was added as an initiator so as to be 7 mol % with respect to the total number of moles of all monomers, and the mixture was heated at 85° C. for about 5 hours to carry out polymerization. rice field. After that, the polymerization reaction solution is poured into a large amount of n-heptane to precipitate the resin, which is then filtered and collected to obtain a resin A4 (copolymer) having a weight average molecular weight of about 5.3×10 ³ with a yield of 68. obtained in %. This resin A4 has the following structural units.

Example 5 [Synthesis of Resin A5]
As monomers, monomer (a1-4-2), monomer (a1-1-3), monomer (a1-2-6), monomer (a2-1-3), monomer (a3-4-2) and monomer ( I-1), the molar ratio [monomer (a1-4-2): monomer (a1-1-3): monomer (a1-2-6): monomer (a2-1-3): monomer (a3 -4-2): Monomer (I-1)] are mixed in a ratio of 32:20:25:3:10:10, and further, to this monomer mixture, , and 1.5 times the mass of methyl isobutyl ketone. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. Thereafter, after cooling the polymerization reaction solution to 23° C., an aqueous solution of p-toluenesulfonic acid was added, stirred for 3 hours, and separated. The collected organic layer was poured into a large amount of n-heptane to precipitate the resin, filtered and collected to obtain Resin A5 having a weight average molecular weight of about 6.0×10 ³ with a yield of 62%. This resin A5 has the following structural units.

Example 6 [Synthesis of Resin A6]
As monomers, monomer (a1-4-2), monomer (a1-1-3), monomer (a1-2-6), monomer (a2-1-3), monomer (a3-2-1) and monomer ( I-1), the molar ratio [monomer (a1-4-2): monomer (a1-1-3): monomer (a1-2-6): monomer (a2-1-3): monomer (a3 -2-1): Monomer (I-1)] are mixed in a ratio of 32:20:25:3:10:10, and further, to this monomer mixture, , and 1.5 times the mass of methyl isobutyl ketone. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. Thereafter, after cooling the polymerization reaction solution to 23° C., an aqueous solution of p-toluenesulfonic acid was added, stirred for 3 hours, and separated. The collected organic layer was poured into a large amount of n-heptane to precipitate the resin, filtered and collected to obtain Resin A6 having a weight average molecular weight of about 6.3×10 ³ with a yield of 58%. This resin A6 has the following structural units.

Example 7 [Synthesis of Resin A7]
As monomers, monomer (a1-4-2), monomer (a1-1-3), monomer (a1-2-6), monomer (a3-2-1) and monomer (I-1) are used, and the mol The ratio [monomer (a1-4-2):monomer (a1-1-3):monomer (a1-2-6):monomer (a3-2-1):monomer (I-1)] is 32:20 :25:13:10, and this monomer mixture was further mixed with methyl isobutyl ketone in an amount of 1.5 times the mass of the total mass of all the monomers. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. Thereafter, after cooling the polymerization reaction solution to 23° C., an aqueous solution of p-toluenesulfonic acid was added, stirred for 3 hours, and separated. The collected organic layer was poured into a large amount of n-heptane to precipitate the resin, filtered and collected to obtain Resin A7 having a weight average molecular weight of about 6.1×10 ³ with a yield of 63%. This resin A7 has the following structural units.

Example 8 [Synthesis of Resin A8]
As monomers, monomer (a1-4-2), monomer (a1-1-3), monomer (a3-2-1) and monomer (I-1) are used, and the molar ratio [monomer (a1-4-2 ):monomer (a1-1-3):monomer (a3-2-1):monomer (I-1)] are mixed so that the ratio is 32:20:13:35, and this monomer mixture 1.5 times the mass of methyl isobutyl ketone with respect to the total mass of all monomers was mixed. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. Thereafter, after cooling the polymerization reaction solution to 23° C., an aqueous solution of p-toluenesulfonic acid was added, stirred for 3 hours, and separated. The collected organic layer was poured into a large amount of n-heptane to precipitate the resin, filtered and collected to obtain Resin A8 having a weight average molecular weight of about 6.4×10 ³ with a yield of 55%. This resin A8 has the following structural units.

Example 9 [Synthesis of Resin A9]
As monomers, monomer (a2-2-1), monomer (a1-1-3), monomer (a3-2-1) and monomer (I-1) are used, and the molar ratio [monomer (a2-2-1 ):monomer (a1-1-3):monomer (a3-2-1):monomer (I-1)] are mixed so that the ratio is 32:20:13:35, and this monomer mixture 1.5 times the mass of methyl isobutyl ketone with respect to the total mass of all monomers was mixed. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. After that, the polymerization reaction solution was poured into a large amount of n-heptane to precipitate a resin, which was filtered and collected to obtain Resin A9 having a weight average molecular weight of about 6.0×10 ³ with a yield of 55%. This resin A9 has the following structural units.

Example 10 [Synthesis of Resin A10]
As monomers, using monomer (a2-2-1), monomer (a1-4-2), monomer (a1-1-3), monomer (a3x-2-1) and monomer (I-1), the mole The ratio [monomer (a2-2-1):monomer (a1-4-2):monomer (a1-1-3):monomer (a3x-2-1):monomer (I-1)] is 15:15 :20:35:15, and this monomer mixture was further mixed with methyl isobutyl ketone in an amount of 1.5 times the mass of the total mass of all the monomers. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of n-heptane to precipitate the resin, which was filtered and collected to obtain Resin A10 having a weight average molecular weight of about 6.5×10 ³ with a yield of 55%. This resin A10 has the following structural units.

Example 11 [Synthesis of Resin A11]
As monomers, monomer (a1-4-2), monomer (a1-1-3), monomer (a3-2-1) and monomer (I-1) are used, and the molar ratio [monomer (a1-4-2 ):monomer (a1-1-3):monomer (a3-2-1):monomer (I-1)] are mixed so that the ratio is 30:20:30:20, and this monomer mixture 1.5 times the mass of methyl isobutyl ketone with respect to the total mass of all monomers was mixed. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. Thereafter, after cooling the polymerization reaction solution to 23° C., an aqueous solution of p-toluenesulfonic acid was added, stirred for 3 hours, and separated. The collected organic layer was poured into a large amount of n-heptane to precipitate the resin, filtered and collected to obtain Resin A11 having a weight average molecular weight of about 5.9×10 ³ with a yield of 50%. This resin A11 has the following structural units.

Example 12 [Synthesis of Resin A12]
As monomers, acetoxystyrene, monomer (a1-1-3), monomer (a1-2-6) and monomer (I-3) are used, and the molar ratio [acetoxystyrene:monomer (a1-1-3): Monomer (a1-2-6): Monomer (I-3)] is mixed so that the ratio is 38:24:28:10, and further, to this monomer mixture, 1.5 times by mass of methyl isobutyl ketone was mixed. To the obtained mixture, azobisisobutyronitrile was added as an initiator so as to be 7 mol % with respect to the total number of moles of all monomers, and the mixture was heated at 85° C. for about 5 hours to carry out polymerization. rice field. Thereafter, a 25% tetramethylammonium hydroxide aqueous solution was added to the polymerization reaction solution, stirred for 12 hours, and then separated. The obtained organic layer is poured into a large amount of n-heptane to precipitate the resin, which is then filtered and collected to obtain a resin A12 (copolymer) having a weight average molecular weight of about 5.6×10 ³ with a yield of 58. obtained in %. This resin A12 has the following structural units.

Example 13 [Synthesis of resin A13]
As monomers, acetoxystyrene, monomer (a1-1-3) and monomer (I-2) are used, and the molar ratio [acetoxystyrene:monomer (a1-1-3):monomer (I-2)] is They were mixed in a ratio of 38:24:38, and methyl isobutyl ketone was added to the monomer mixture in an amount of 1.5 times the mass of the total mass of all the monomers. To the obtained mixture, azobisisobutyronitrile was added as an initiator so as to be 7 mol % with respect to the total number of moles of all monomers, and the mixture was heated at 85° C. for about 5 hours to carry out polymerization. rice field. Thereafter, a 25% tetramethylammonium hydroxide aqueous solution was added to the polymerization reaction solution, stirred for 12 hours, and then separated. The obtained organic layer is poured into a large amount of n-heptane to precipitate the resin, which is then filtered and collected to obtain a resin A13 (copolymer) having a weight average molecular weight of about 5.8×10 ³ with a yield of 63. obtained in %. This resin A13 has the following structural units.

Example 14 [Synthesis of Resin A14]
As monomers, acetoxystyrene, monomer (a1-1-3) and monomer (I-3) are used, and the molar ratio [acetoxystyrene:monomer (a1-1-3):monomer (I-3)] is They were mixed in a ratio of 38:24:38, and methyl isobutyl ketone was added to the monomer mixture in an amount of 1.5 times the mass of the total mass of all the monomers. To the obtained mixture, azobisisobutyronitrile was added as an initiator so as to be 7 mol % with respect to the total number of moles of all monomers, and the mixture was heated at 85° C. for about 5 hours to carry out polymerization. rice field. Thereafter, a 25% tetramethylammonium hydroxide aqueous solution was added to the polymerization reaction solution, stirred for 12 hours, and then separated. The obtained organic layer is poured into a large amount of n-heptane to precipitate the resin, which is then filtered and collected to yield 61% of resin A14 (copolymer) having a weight average molecular weight of about 5.6×10 ³ . obtained in %. This resin A14 has the following structural units.

Example 15 [Synthesis of Resin A15]
As monomers, acetoxystyrene, monomer (a1-1-3), monomer (a1-2-6) and monomer (I-19) were used, and their molar ratio [acetoxystyrene: monomer (a1-1-3): Monomer (a1-2-6): Monomer (I-19)] is mixed in a ratio of 38:24:28:10, and further, to this monomer mixture, 1.5 times by mass of methyl isobutyl ketone was mixed. To the obtained mixture, azobisisobutyronitrile was added as an initiator so as to be 7 mol % with respect to the total number of moles of all monomers, and the mixture was heated at 85° C. for about 5 hours to carry out polymerization. rice field. Thereafter, a 25% tetramethylammonium hydroxide aqueous solution was added to the polymerization reaction solution, stirred for 12 hours, and then separated. The resulting organic layer was poured into a large amount of n-heptane to precipitate the resin, which was then filtered and collected to yield 55% of resin A15 (copolymer) having a weight average molecular weight of about 5.4×10 ³ . obtained in %. This resin A15 has the following structural units.

Example 16 [Synthesis of Resin A16]
As monomers, acetoxystyrene, monomer (a1-1-3) and monomer (I-19) are used, and the molar ratio [acetoxystyrene: monomer (a1-1-3): monomer (I-19)] is They were mixed in a ratio of 38:24:38, and methyl isobutyl ketone was added to the monomer mixture in an amount of 1.5 times the mass of the total mass of all the monomers. To the obtained mixture, azobisisobutyronitrile was added as an initiator so as to be 7 mol % with respect to the total number of moles of all monomers, and the mixture was heated at 85° C. for about 5 hours to carry out polymerization. rice field. Thereafter, a 25% tetramethylammonium hydroxide aqueous solution was added to the polymerization reaction solution, stirred for 12 hours, and then separated. The obtained organic layer is poured into a large amount of n-heptane to precipitate the resin, which is then filtered and collected to obtain a resin A16 (copolymer) having a weight average molecular weight of about 5.4×10 ³ with a yield of 60%. obtained in %. This resin A16 has the following structural units.

Example 17 [Synthesis of resin A17]
As monomers, acetoxystyrene, monomer (a1-1-3), monomer (a1-2-6) and monomer (I-20) were used, and their molar ratio [acetoxystyrene: monomer (a1-1-3): Monomer (a1-2-6): Monomer (I-20)] is mixed in a ratio of 38:24:28:10, and further, to this monomer mixture, 1.5 times by mass of methyl isobutyl ketone was mixed. To the obtained mixture, azobisisobutyronitrile was added as an initiator so as to be 7 mol % with respect to the total number of moles of all monomers, and the mixture was heated at 85° C. for about 5 hours to carry out polymerization. rice field. Thereafter, a 25% tetramethylammonium hydroxide aqueous solution was added to the polymerization reaction solution, stirred for 12 hours, and then separated. The obtained organic layer is poured into a large amount of n-heptane to precipitate the resin, which is then filtered and collected to obtain resin A17 (copolymer) having a weight average molecular weight of about 5.2×10 ³ with a yield of 53. obtained in %. This resin A17 has the following structural units.

Example 18 [Synthesis of resin A18]
As monomers, acetoxystyrene, monomer (a1-1-3) and monomer (I-20) are used, and the molar ratio [acetoxystyrene:monomer (a1-1-3):monomer (I-20)] is They were mixed in a ratio of 38:24:38, and methyl isobutyl ketone was added to the monomer mixture in an amount of 1.5 times the mass of the total mass of all the monomers. To the obtained mixture, azobisisobutyronitrile was added as an initiator so as to be 7 mol % with respect to the total number of moles of all monomers, and the mixture was heated at 85° C. for about 5 hours to carry out polymerization. rice field. Thereafter, a 25% tetramethylammonium hydroxide aqueous solution was added to the polymerization reaction solution, stirred for 12 hours, and then separated. The resulting organic layer was poured into a large amount of n-heptane to precipitate the resin, which was then filtered and collected to yield 55% of resin A18 (copolymer) having a weight average molecular weight of about 5.1×10 ³ . obtained in %. This resin A18 has the following structural units.

Example 19 [Synthesis of resin A19]
As monomers, the monomer (a1-4-2), the monomer (a1-1-3), the monomer (a1-2-6), the monomer (a3-2-1) and the monomer (I-2) are used, and the mol The ratio [monomer (a1-4-2):monomer (a1-1-3):monomer (a1-2-6):monomer (a3-2-1):monomer (I-2)] is 32:20 :25:13:10, and this monomer mixture was further mixed with methyl isobutyl ketone in an amount of 1.5 times the mass of the total mass of all the monomers. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. Thereafter, after cooling the polymerization reaction solution to 23° C., an aqueous solution of p-toluenesulfonic acid was added, stirred for 3 hours, and separated. The collected organic layer was poured into a large amount of n-heptane to precipitate the resin, filtered and collected to obtain Resin A19 having a weight average molecular weight of about 5.9×10 ³ with a yield of 61%. This resin A19 has the following structural units.

Example 20 [Synthesis of resin A20]
As monomers, the monomer (a1-4-2), the monomer (a1-1-3), the monomer (a1-2-6), the monomer (a3-2-1) and the monomer (I-3) are used, and the mol The ratio [monomer (a1-4-2):monomer (a1-1-3):monomer (a1-2-6):monomer (a3-2-1):monomer (I-3)] is 32:20 :25:13:10, and this monomer mixture was further mixed with methyl isobutyl ketone in an amount of 1.5 times the mass of the total mass of all the monomers. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. Thereafter, after cooling the polymerization reaction solution to 23° C., an aqueous solution of p-toluenesulfonic acid was added, stirred for 3 hours, and separated. The collected organic layer was poured into a large amount of n-heptane to precipitate the resin, filtered and collected to obtain Resin A20 having a weight average molecular weight of about 5.7×10 ³ with a yield of 60%. This resin A20 has the following structural units.

Example 21 [Synthesis of resin A21]
As monomers, using monomer (a1-4-2), monomer (a1-1-3), monomer (a1-2-6), monomer (a3-2-1) and monomer (I-19), the mole The ratio [monomer (a1-4-2):monomer (a1-1-3):monomer (a1-2-6):monomer (a3-2-1):monomer (I-19)] is 32:20 :25:13:10, and this monomer mixture was further mixed with methyl isobutyl ketone in an amount of 1.5 times the mass of the total mass of all the monomers. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. Thereafter, after cooling the polymerization reaction solution to 23° C., an aqueous solution of p-toluenesulfonic acid was added, stirred for 3 hours, and separated. The collected organic layer was poured into a large amount of n-heptane to precipitate the resin, filtered and collected to obtain Resin A21 having a weight average molecular weight of about 5.5×10 ³ with a yield of 58%. This resin A21 has the following structural units.

Example 22 [Synthesis of Resin A22]
As monomers, monomer (a1-4-2), monomer (a1-1-3), monomer (a1-2-6), monomer (a3-2-1) and monomer (I-20) are used, and the mol The ratio [monomer (a1-4-2):monomer (a1-1-3):monomer (a1-2-6):monomer (a3-2-1):monomer (I-20)] is 32:20 :25:13:10, and this monomer mixture was further mixed with methyl isobutyl ketone in an amount of 1.5 times the mass of the total mass of all the monomers. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. Thereafter, after cooling the polymerization reaction solution to 23° C., an aqueous solution of p-toluenesulfonic acid was added, stirred for 3 hours, and separated. The collected organic layer was poured into a large amount of n-heptane to precipitate the resin, filtered and collected to obtain Resin A22 having a weight average molecular weight of about 5.2×10 ³ with a yield of 55%. This resin A22 has the following structural units.

Synthesis Example 1 [Synthesis of Resin AX1]
As monomers, monomer (a2-2-1), monomer (a1-4-2), monomer (a3x-2-1) and monomer (I-1) are used, and the molar ratio [monomer (a2-2-1 ):monomer (a1-4-2):monomer (a3x-2-1):monomer (I-1)] are mixed so that the ratio is 15:35:35:15, and this monomer mixture 1.5 times the mass of methyl isobutyl ketone with respect to the total mass of all monomers was mixed. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of n-heptane to precipitate the resin, which was filtered and collected to obtain resin AX1 having a weight average molecular weight of about 6.3×10 ³ with a yield of 75%. This resin AX1 has the following structural units.

Synthesis Example 2 [Synthesis of Resin AX2]
As monomers, monomer (a1-4-2), monomer (a3-2-1) and monomer (I-1) are used, and the molar ratio [monomer (a1-4-2): monomer (a3-2-1 ):monomer (I-1)] are mixed in a ratio of 30:30:40, and to this monomer mixture, methyl isobutyl ketone is added in an amount 1.5 times the weight of the total weight of all the monomers. were mixed. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. Thereafter, after cooling the polymerization reaction solution to 23° C., an aqueous solution of p-toluenesulfonic acid was added, stirred for 3 hours, and separated. The collected organic layer was poured into a large amount of n-heptane to precipitate the resin, filtered and collected to obtain resin AX2 having a weight average molecular weight of about 6.0×10 ³ with a yield of 78%. This resin AX2 has the following structural units.

Synthesis Example 3 [Synthesis of Resin AX3]
As monomers, monomer (a1-4-2), monomer (a3-2-1) and monomer (a1-1-3) are used, and the molar ratio [monomer (a1-4-2): monomer (a3-2 -1):monomer (a1-1-3)] are mixed so that the ratio is 30:30:40, and further, 1.5 times the mass of the total mass of all the monomers is added to this monomer mixture. of methyl isobutyl ketone was mixed. To the resulting mixture, azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers. C. for about 5 hours. Thereafter, after cooling the polymerization reaction solution to 23° C., an aqueous solution of p-toluenesulfonic acid was added, stirred for 3 hours, and separated. The collected organic layer was poured into a large amount of n-heptane to precipitate the resin, filtered and collected to obtain resin AX3 having a weight average molecular weight of about 5.5×10 ³ with a yield of 58%. This resin AX3 has the following structural units.

<Preparation of resist composition>
A mixture obtained by mixing and dissolving each component shown in Table 1 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）＞
（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）
Ｄ１：特開２０１１－３９５０２号公報記載の方法で合成

＜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 ４００部
プロピレングリコールモノメチルエーテル １５０部
γ－ブチロラクトン ５部 <Resin>
A1-A22, AX1-AX3: Resin A1-Resin A22, Resin AX1-Resin AX3
<Acid generator (B)>
B1-43: a salt represented by the formula (B1-43) (synthesized according to the examples of JP-A-2016-47815)

<Quencher (C)>
(Salt that generates an acid with a weaker acidity than the acid generated from the acid generator)
D1: synthesized by the method described in JP-A-2011-39502

<Solvent>
Propylene glycol monomethyl ether acetate 400 parts Propylene glycol monomethyl ether 150 parts γ-butyrolactone 5 parts

(Evaluation of resist composition by electron beam exposure: alkali development)
A 6-inch silicon wafer was treated with hexamethyldisilazane at 90° C. for 60 seconds on a direct hotplate. This silicon wafer was spin-coated with the resist composition so that the film thickness of the composition layer was 0.04 μm. After that, it was pre-baked for 60 seconds on a direct hot plate at the temperature shown in the "PB" column of Table 1 to form a composition layer. A contact hole pattern (hole pitch 40 nm/hole diameter 17 nm) were directly written.
After exposure, post-exposure baking was performed on a hot plate at the temperature shown in the "PEB" column of Table 1 for 60 seconds, and puddle development was performed for 60 seconds with a 2.38% by mass tetramethylammonium hydroxide aqueous solution. , a resist pattern was obtained.
In the resist pattern obtained after development, the effective sensitivity was defined as the amount of exposure at which the hole diameter formed using the mask was 17 nm.

比較組成物１～３と比較して、組成物１～４、１０～１８での標準偏差が小さく、ＣＤ均一性（ＣＤＵ）評価が良好であった。 <CD uniformity (CDU) evaluation>
In the effective sensitivity, the hole diameter of a pattern formed with a mask having a hole diameter of 17 nm was measured 24 times for each hole, and the average value was taken as the average hole diameter of one hole. A standard deviation was obtained by using a population of 400 measured average hole diameters of a pattern formed by a mask having a hole diameter of 17 nm in the same wafer.
Table 2 shows the results. Numerical values in parentheses indicate standard deviations (nm).

Compared to Comparative Compositions 1-3, Compositions 1-4 and 10-18 had smaller standard deviations and better CD Uniformity (CDU) ratings.

(Evaluation of resist composition by electron beam exposure: butyl acetate development)
A 6-inch silicon wafer was treated with hexamethyldisilazane at 90° C. for 60 seconds on a direct hotplate. This silicon wafer was spin-coated with the resist composition so that the film thickness of the composition layer was 0.04 μm. After that, it was pre-baked for 60 seconds on a direct hot plate at the temperature shown in the "PB" column of Table 1 to form a composition layer. The composition layer formed on the wafer is exposed to a contact hole pattern (hole pitch 50 nm/hole diameter 23 nm).
After the exposure, post-exposure baking was performed for 60 seconds on a hot plate at the temperature shown in the "PEB" column of Table 1. Next, the composition layer on the silicon wafer was developed using butyl acetate (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as a developer by a dynamic dispensing method at 23° C. for 20 seconds to obtain a resist pattern. .
In the resist pattern obtained after development, the effective sensitivity was defined as the exposure amount at which the hole diameter formed using the mask was 23 nm.

比較組成物１～３と比較して、組成物５～１１、１９～２２での標準偏差が小さく、ＣＤ均一性（ＣＤＵ）評価が良好であった。 <CD uniformity (CDU) evaluation>
In the effective sensitivity, the hole diameter of a pattern formed with a mask having a hole diameter of 23 nm was measured 24 times for each hole, and the average value was taken as the average hole diameter of one hole. A standard deviation was obtained by using a population of 400 measured average hole diameters of patterns formed by a mask having a hole diameter of 23 nm in the same wafer.
Table 3 shows the results. Numerical values in parentheses indicate standard deviations (nm).

Compared to Comparative Compositions 1-3, Compositions 5-11 and 19-22 had smaller standard deviations and better CD Uniformity (CDU) ratings.

INDUSTRIAL APPLICABILITY The resin and the resist composition containing the resin of the present invention can obtain a resist pattern having good CD uniformity (CDU).

Claims (4)

A resin containing a structural unit represented by formula (I), a structural unit represented by formula (a1-1) and a structural unit represented by formula (a2-A) , an acid generator, and an acid generator and a carboxylate that generates an acid that is weaker in acidity than the generated acid .

[in the formula (I),
R ¹ represents a hydrogen atom or a methyl group.
R ² , R ³ and R ⁴ each independently represent an alkyl group having 1 to 4 carbon atoms.
R ⁵ represents an alkyl group having 1 to 8 carbon atoms.
m represents any integer from 0 to 8;
n represents an integer of 0 to 3; ]

[In the formula (a1-1),
L ^a1 represents -O- or *-O-(CH ₂ ) _k1 -CO-O-, k1 represents an integer of 1 to 7, and * represents a bond with -CO-.
R ^a4 represents a hydrogen atom or a methyl group.
R ^a6 represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
m1 represents any integer from 0 to 14; ]

[In the formula (a2-A),
R ^a50 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a51 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl It represents an oxy group or a methacryloyloxy group.
A ^a50 represents a single bond or ^* -X ^a51 -(A ^a52 -X ^a52 ) _nb -, and * represents a bonding site with the carbon atom to which -R ^a50 bonds.
A ^a52 represents an alkanediyl group having 1 to 6 carbon atoms.
X ^a51 and X ^a52 each independently represent -O-, -CO-O- or -O-CO-.
nb represents 0 or 1;
mb represents an integer from 0 to 4; When mb is any integer of 2 or more, multiple R ^a51 may be the same or different. ] 2. The resist composition according to claim 1, further comprising a structural unit represented by formula (a1-2).

[In formula (a1-2),
L ^a2 represents -O- or *-O-(CH ₂ ) _k1 -CO-O-, k1 represents an integer of 1 to 7, and * represents a bond with -CO-.
R ^a5 represents a hydrogen atom or a methyl group.
R ^a7 represents an alkyl group having 1 to 3 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
n1 represents any integer from 0 to 10;
n1' represents an integer of 0 to 3; ] 3. The resist composition according to claim 1 , wherein the acid generator contains a salt represented by formula (B1).

[In formula (B1),
Q ^b1 and Q ^b2 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced with —O— or —CO— , a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Y represents an optionally substituted methyl group or an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, included in the alicyclic hydrocarbon group- CH ₂ - may be replaced by -O-, -S(O) ₂ - or -CO-.
Z ⁺ represents an organic cation. ] (1) a step of applying the resist composition according to any one of claims 1 to 3 onto a substrate;
(2) a step of drying the applied composition to form a composition layer;
(3) exposing the composition layer;
(4) heating the composition layer after exposure; and (5) developing the composition layer after heating;
A method of manufacturing a resist pattern comprising: