JP7389589B2 - Acid generator, resist composition, and method for producing resist pattern - Google Patents

Description

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

特許文献２には、下記式で表される塩及び該塩を酸発生剤として含有するレジスト組成物が記載されている。

特許文献２には、下記式で表される塩及び該塩を酸発生剤として含有するレジスト組成物も記載されている。

特許文献３には、下記式で表される塩及び該塩を酸発生剤として含有するレジスト組成物が記載されている。

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

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

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

Patent Document 3 describes a salt represented by the following formula and a resist composition containing the salt as an acid generator.

Japanese Patent Application Publication No. 2004-203858 Japanese Patent Application Publication No. 2005-097254 Japanese Patent Application Publication No. 09-244234

An object of the present invention is to provide a salt that forms a resist pattern with better line edge roughness (LER) than a resist pattern formed from a resist composition containing the above salt.

［式（ａ１－１）及び式（ａ１－２）中、
Ｌ^ａ１及びＬ^ａ２は、それぞれ独立に、－Ｏ－又は＊－Ｏ－（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及びＲ^ａ５は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^ａ６及びＲ^ａ７は、それぞれ独立に、炭素数１～８のアルキル基、炭素数３～１８の脂環式炭化水素基又はこれらを組合せた基を表す。
ｍ１は、０～１４のいずれかの整数を表す。
ｎ１は、０～１０のいずれかの整数を表す。
ｎ１’は、０～３のいずれかの整数を表す。］
［６］酸不安定基を有する樹脂が、さらに式（ａ２－Ａ）で表される構造単位を含む［４］又は［５］記載のレジスト組成物。

［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。］
［７］酸発生剤から発生する酸よりも酸性度の弱い酸を発生する塩をさらに含有する［４］～［６］のいずれかに記載のレジスト組成物。
［８］（１）［４］～［７］のいずれかに記載のレジスト組成物を基板上に塗布する工程、
（２）塗布後の組成物を乾燥させて組成物層を形成する工程、
（３）組成物層に露光する工程、
（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] Salt represented by formula (I).
[In formula (I),
R ¹ represents a hydrocarbon group containing a cyclic hydrocarbon group having 3 to 18 carbon atoms (the cyclic hydrocarbon group may have a substituent), and -CH ₂ - contained in the hydrocarbon group may be replaced with -O-, -S-, -SO ₂ - or -CO-.
R ² represents a halogen atom or an alkyl group having 1 to 6 carbon atoms.
m2 represents any integer from 0 to 4, and when m2 is 2 or more, a plurality of R ² may be the same or different.
Z ⁺ represents an organic cation. ]
[2] R ¹ is a hydrocarbon group containing a monocyclic alicyclic hydrocarbon group having 3 to 8 carbon atoms (the alicyclic hydrocarbon group may have a substituent) -CH ₂ - contained in the group may be replaced with -O-, -S-, -SO ₂ - or -CO-), or alicyclic carbonization of a polycyclic ring having 6 to 12 carbon atoms. A hydrocarbon group containing a hydrogen group (the alicyclic hydrocarbon group may have a substituent) (-CH ₂ - contained in the hydrocarbon group is -O-, -S-, -SO ₂ - or -CO- may be substituted.) The salt according to [1].
[3] An acid generator containing the salt described in [1] or [2].
[4] A resist composition containing the acid generator according to [3] and a resin having an acid-labile group.
[5] The resist composition according to [4], wherein the resin having an acid-labile group contains at least one of a structural unit represented by formula (a1-1) and a structural unit represented by formula (a1-2). thing.

[In formula (a1-1) and formula (a1-2),
L ^a1 and L ^a2 each independently represent -O- or *-O-(CH ₂ ) _k1 -CO-O-, k1 represents an integer from 1 to 7, and * represents a bond with -CO- represents a hand.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
m1 represents any integer from 0 to 14.
n1 represents any integer from 0 to 10.
n1' represents any integer from 0 to 3. ]
[6] The resist composition according to [4] or [5], wherein the resin having an acid-labile group further contains a structural unit represented by formula (a2-A).

[In 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, hydroxy group, alkyl group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms, alkylcarbonyl group having 2 to 4 carbon atoms, alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl 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 is bonded.
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 any integer from 0 to 4. When mb is any integer of 2 or more, a plurality of R ^a51 's may be the same or different. ]
[7] The resist composition according to any one of [4] to [6], further containing a salt that generates an acid that is weaker in acidity than the acid generated from the acid generator.
[8] (1) Applying the resist composition according to any one of [4] to [7] onto a substrate,
(2) drying the applied composition to form a composition layer;
(3) exposing the composition layer to light;
(4) A method for producing a resist pattern, including the steps of: heating the exposed composition layer; and (5) developing the heated composition layer.

By using a resist composition using the salt of the present invention, a resist pattern with good line edge roughness (LER) can be manufactured.

In this specification, "(meth)acrylic monomer" refers to monomers having a structure of "CH ₂ = CH-CO-" and monomers having a structure of "CH ₂ = C(CH ₃ )-CO-". It means at least one kind selected from the group consisting of: Similarly, "(meth)acrylate" and "(meth)acrylic acid" refer to "at least one type selected from the group consisting of acrylate and methacrylate" and "at least one type selected from the group consisting of acrylic acid and methacrylic acid," respectively. ” means. When a structural unit having "CH ₂ = C(CH ₃ )-CO-" or "CH ₂ = CH-CO-" is exemplified, a structural unit having both groups is similarly exemplified. shall be taken as a thing. Moreover, in the groups described in this specification, those that can have both a linear structure and a branched structure may have either of them. A "combined group" means a group in which two or more of the exemplified groups are bonded together with their valences appropriately changed. If stereoisomers exist, all stereoisomers are included.
As used herein, "solid content of the resist composition" refers to the total amount of components excluding the solvent (E) described below from the total amount of the resist composition.

<Salt represented by formula (I)>
The present invention relates to a salt represented by formula (I) (hereinafter sometimes referred to as "salt (I)").
Of the salt (I), the side having a negative charge may be referred to as an "anion (I)", and the side having a positive charge may be referred to as a "cation (I)".

The hydrocarbon group containing a cyclic hydrocarbon group in R ¹ includes monocyclic or polycyclic alicyclic hydrocarbon groups having 3 to 18 carbon atoms, aromatic hydrocarbon groups having 6 to 18 carbon atoms, etc. Examples include a hydrocarbon group or a combination thereof, a group consisting of any combination of a cyclic hydrocarbon group and a chain hydrocarbon group having 1 to 6 carbon atoms (alkyl group, alkenyl group, alkynyl group), and the like.

The alicyclic hydrocarbon group may be monocyclic, polycyclic, or spirocyclic, and may be saturated or unsaturated. Examples of alicyclic hydrocarbon groups include monocyclic cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, and cyclododecyl group; Examples include polycyclic cycloalkyl groups such as decahydronaphthyl, norbornyl, and adamantyl groups.
Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, naphthyl group, biphenyl group, anthryl group, phenanthryl group, and binaphthyl group.

Examples of alkyl groups include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, and dodecyl group. Examples include alkyl groups such as groups. The alkyl group preferably has 1 to 9 carbon atoms, more preferably 1 to 4 carbon atoms.
Examples of the alkenyl group include an ethenyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a tert-butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octynyl group, an isooctynyl group, and a nonenyl group.
Examples of the alkynyl group include ethynyl group, propynyl group, isopropynyl group, butynyl group, isobutynyl group, tert-butynyl group, pentynyl group, hexynyl group, octynyl group, nonynyl group, and the like.

As a combined group,
A group consisting of a combination of an alicyclic hydrocarbon group and an aromatic hydrocarbon group (-CH ₂ - contained in the combined group is replaced with -O-, -S-, -CO- or -SO ₂ -) ),
A group that combines a cyclic hydrocarbon group and a chain hydrocarbon group (alkyl group, alkenyl group, alkynyl group) (-CH ₂ - contained in the combined group is -O-, -S-, -CO- or -SO ₂ -), that is,
A group that combines an alicyclic hydrocarbon group and a chain hydrocarbon group (alkyl group, alkenyl group, alkynyl group) (-CH ₂ - contained in the combined group is -O-, -S-, - CO- or -SO ₂ - may be substituted) and a group that combines an aromatic hydrocarbon group and a chain hydrocarbon group (alkyl group, alkenyl group, alkynyl group) (included in the combined group) CH ₂ - may be replaced with -O-, -S-, -CO- or -SO ₂ -.
In addition, in the combination, two or more types of alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and chain hydrocarbon groups (alkyl groups, alkenyl groups, alkynyl groups, etc.) may be combined. Moreover, any group may be bonded to an oxygen atom. Further, the above-mentioned groups may contain groups having different valences (alkanediyl group, alkanetriyl group, cycloalkanediyl group, cycloalkanetriyl group, etc.). The total carbon number of the hydrocarbon groups including the cyclic hydrocarbon group in R ¹ is, for example, 3 to 24, preferably 3 to 18, and more preferably 5 to 12.

Specific examples of combined groups include:
Alicyclic hydrocarbon groups - chain hydrocarbon groups - * (included in the chain hydrocarbon group and the alicyclic hydrocarbon group) such as adamantylmethyl group, adamantylethyl group, cyclohexylmethyl group, cyclohexylethyl group, etc. -CH ₂ - may be replaced with -O-, -S-, -CO- or -SO ₂ -),
Chain hydrocarbon group - alicyclic hydrocarbon group - * (-CH ₂ - contained in the chain hydrocarbon group and the alicyclic hydrocarbon group) such as methyladamantyl group, methylcyclohexyl group, dimethylcyclohexyl group, etc. may be replaced with -O-, -S-, -CO- or -SO ₂ -),
Chain hydrocarbon groups such as tolyl group and xylyl group - aromatic hydrocarbon group -* (-CH ₂ - contained in the chain hydrocarbon group is -O-, -S-, -CO- or - may be replaced by SO ₂ -),
Chain hydrocarbon group - alicyclic hydrocarbon group - chain hydrocarbon group - *(-CH ₂ - contained in the chain hydrocarbon group and the alicyclic hydrocarbon group) such as methylcyclohexylmethyl group , -O-, -S-, -CO- or -SO ₂ -),
Aromatic hydrocarbon group - chain hydrocarbon group - such as benzyl group, phenethyl group -* (-CH ₂ - contained in the chain hydrocarbon group is -O-, -S-, -CO- or - may be replaced by SO ₂ -),
Chain hydrocarbon group such as tolylmethyl group - aromatic hydrocarbon group - chain hydrocarbon group -* (-CH ₂ - contained in the chain hydrocarbon group is -O-, -S-, -CO - or -SO ₂ - may be replaced),
An aromatic hydrocarbon group such as a phenyladamantyl group - an alicyclic hydrocarbon group -* (-CH ₂ - contained in the alicyclic hydrocarbon group is -O-, -S-, -CO- or - may be replaced by SO ₂ -),
Alicyclic hydrocarbon group - aromatic hydrocarbon group - such as cyclohexylphenyl group, adamantyl phenyl group -* (-CH ₂ - contained in the alicyclic hydrocarbon group is -O-, -S-, - may be replaced with CO- or -SO ₂ -, and the like. Here, * represents a bonding site with an oxygen atom.

When -CH ₂ - contained in the hydrocarbon group represented by R ¹ is replaced with -O-, -S-, -CO- or -SO ₂ -, the number of carbon atoms before being replaced is the same as that of the hydrocarbon group. The total number of carbon atoms is Also, the number may be one, or two or more,

Examples of substituents that the cyclic hydrocarbon group may have include a halogen atom, a cyano group, and an alkyl group having 1 to 12 carbon atoms, and -CH ₂ - contained in the alkyl group is -O-, -S-, -CO- or -SO ₂ - may be substituted.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, octyl group, nonyl group, and the like.
When -CH ₂ - contained in an alkyl group is replaced with -O- or -CO- as a substituent, the number of carbon atoms before being replaced is the total number of carbon atoms in the alkyl group. Hydroxy group (a group in which -CH ₂ - contained in a methyl group is replaced with -O-), carboxyl group (a group in which -CH ₂ -CH ₂ - contained in an ethyl group is replaced with -O-CO-) group), an alkoxy group having 1 to 11 carbon atoms (a group in which -CH ₂ - contained in an alkyl group having 2 to 12 carbon atoms is replaced with -O-), an alkoxycarbonyl group having 2 to 11 carbon atoms (a group in which -O- is substituted for -CH 2 - contained in an alkyl group having 2 to 12 carbon atoms), A group in which -CH ₂ -CH ₂ - contained in an alkyl group having 3 to 12 carbon atoms is replaced with -O-CO-), an alkylcarbonyl group having 2 to 12 carbon atoms (a group in which -CH 2 -CH 2 - contained in an alkyl group having 3 to 12 carbon atoms is replaced with -O-CO-) -CH ₂ - contained in the group is replaced with -CO-), an alkylcarbonyloxy group having 2 to 11 carbon atoms (-CH ₂ -CH ₂ - contained in the alkyl group having 3 to 12 carbon atoms), -CO-O-) and the like.
Examples of the alkoxy group having 1 to 11 carbon atoms include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, undecyloxy group. Examples include groups.
The alkoxycarbonyl group having 2 to 11 carbon atoms, the alkylcarbonyl group having 2 to 12 carbon atoms, and the alkylcarbonyloxy group having 2 to 11 carbon atoms are groups in which a carbonyl group or carbonyloxy group is bonded to the above-mentioned alkyl group or alkoxy group. represents.
Examples of the alkoxycarbonyl group having 2 to 11 carbon atoms include methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group, and examples of the alkylcarbonyl group having 2 to 12 carbon atoms include acetyl group, propionyl group, butyryl group, etc. Examples of the alkylcarbonyloxy group having 2 to 11 carbon atoms include an acetyloxy group, a propionyloxy group, a butyryloxy group, and the like.
The cyclic hydrocarbon group having 3 to 18 carbon atoms may have one or more substituents.

A cyclic hydrocarbon group having 3 to 18 carbon atoms (the cyclic hydrocarbon group may have a substituent, and -CH ₂ - contained in the alicyclic hydrocarbon group is -O-, -S-, -SO ₂ - or -CO-) may be replaced with
An alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent (-CH ₂ - contained in the alicyclic hydrocarbon group is -O-, -S-, -SO ₂ - or -CO- may be substituted), or
It is preferably an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent,
An alicyclic hydrocarbon group having 3 to 18 carbon atoms that may have one or more members selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, and a fluorine atom (included in the alicyclic hydrocarbon group) -CH ₂ - may be replaced with -O-, -S-, -SO ₂ - or -CO-), or
More preferably, it is an aromatic hydrocarbon group having 6 to 18 carbon atoms, which may have one or more members selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxyl group, and a fluorine atom,
A monocyclic alicyclic hydrocarbon group having 3 to 8 carbon atoms which may have one or more members selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, and a fluorine atom (the alicyclic hydrocarbon group) -CH ₂ - contained in the group may be replaced with -O-, -S-, -SO ₂ - or -CO-), or
A polycyclic alicyclic hydrocarbon group having 6 to 12 carbon atoms which may have one or more members selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, and a fluorine atom (the alicyclic hydrocarbon -CH ₂ - contained in the group may be replaced by -O-, -S-, -SO ₂ - or -CO-).

A hydrocarbon group containing a cyclic hydrocarbon group having 3 to 18 carbon atoms (the cyclic hydrocarbon group may have a substituent) represented by R ¹ (-CH ₂ - contained in the hydrocarbon group) may be replaced with -O-, -S-, -SO ₂ - or -CO-.)
Preferably, an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent (-CH ₂ - contained in the alicyclic hydrocarbon group is -O-, -S-, -SO ₂ - or -CO-), an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent, and a fatty acid having 3 to 18 carbon atoms which may have a substituent. A group that combines a cyclic hydrocarbon group and a chain hydrocarbon group having 1 to 6 carbon atoms (-CH ₂ - contained in the combined group is -O-, -S-, -SO ₂ - or - (may be substituted with CO-), or a group combining an aromatic hydrocarbon group having 6 to 18 carbon atoms and a chain hydrocarbon group having 1 to 6 carbon atoms, which may have a substituent ( -CH ₂ - contained in the combined group may be replaced with -O-, -S-, -SO ₂ - or -CO-),
More preferably, an alicyclic hydrocarbon group having 3 to 18 carbon atoms (the alicyclic hydrocarbon -CH ₂ - contained in the hydrogen group may be replaced with -O-, -S-, -SO ₂ - or -CO-), an alkyl group having 1 to 4 carbon atoms, a hydroxy group, and a fluorine atom. an aromatic hydrocarbon group having 6 to 18 carbon atoms, which may have one or more selected from the group consisting of; or one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, and a fluorine atom; A group consisting of a combination of an alicyclic hydrocarbon group having 3 to 18 carbon atoms and a chain hydrocarbon group having 1 to 6 carbon atoms (-CH ₂ - contained in the combined group is - may be replaced with O-, -S-, -SO ₂ - or -CO-),
More preferably, a monocyclic alicyclic hydrocarbon group having 3 to 8 carbon atoms (the alicyclic -CH ₂ - contained in the cyclic hydrocarbon group may be replaced with -O-, -S-, -SO ₂ - or -CO-), an alkyl group having 1 to 4 carbon atoms, a hydroxy group and a polycyclic alicyclic hydrocarbon group having 6 to 12 carbon atoms which may have one or more atoms selected from the group consisting of fluorine atoms (-CH ₂ - contained in the alicyclic hydrocarbon group is - (may be replaced with O-, -S-, -SO ₂ - or -CO-), an alkyl group having 1 to 4 carbon atoms, a hydroxy group, and a fluorine atom. A group that combines a monocyclic alicyclic hydrocarbon group having 3 to 8 carbon atoms and a chain hydrocarbon group having 1 to 6 carbon atoms (-CH ₂ -- contained in the combined group is -O -, -S-, -SO ₂ - or -CO-), or one or more selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, a hydroxy group, and a fluorine atom. A group that combines a polycyclic alicyclic hydrocarbon group having 6 to 12 carbon atoms and a chain hydrocarbon group having 1 to 6 carbon atoms (-CH ₂ - contained in the combined group is - may be replaced with O-, -S-, -SO ₂ - or -CO-),
Particularly preferably, a monocyclic alicyclic hydrocarbon group having 3 to 8 carbon atoms (the alicyclic -CH ₂ - contained in the cyclic hydrocarbon group may be replaced with -O-, -S-, -SO ₂ - or -CO-), or an alkyl group having 1 to 4 carbon atoms, A polycyclic alicyclic hydrocarbon group having 6 to 12 carbon atoms which may have one or more members selected from the group consisting of a hydroxy group and a fluorine atom (-CH ₂ - contained in the alicyclic hydrocarbon group) , -O-, -S-, -SO ₂ - or -CO-).

Examples of the alkyl group having 1 to 6 carbon atoms for R ² include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, and hexyl group. The number of carbon atoms in the alkyl group is preferably 1 to 4.
Examples of the halogen atom for R ² include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
m2 is an integer of 0 to 4, preferably an integer of 0 to 2. In one embodiment, m2 is preferably zero. In another embodiment, m2 is preferably 1 or 2. When m2 ^is 1, ^R2 is preferably a halogen atom, and more preferably a fluorine atom or an iodine atom. When m2 is 2, one of ^R2 is a halogen atom, the other is preferably a halogen atom or an alkyl group having 1 to 4 carbon atoms, one of ^R2 is a fluorine atom or an iodine atom, and the other is more preferably a fluorine atom, an iodine atom, or an alkyl group having 1 to 3 carbon atoms.

Examples of the anion (I) include the following anions. Among these, anions represented by formulas (Ia-1) to (Ia-9), formula (Ia-16), and formulas (Ia-18) to (Ia-26) are preferred.

In the anion (I), in particular, when there is only one electron-withdrawing property due to an ester group at the meta position with respect to the SO ₃ ^- group, compared to when there are two electron-withdrawing properties due to ester groups, , in a resist composition as described below, line edge roughness (LER) during resist pattern formation can be effectively affected. In particular, when R ¹ has a leaving group and has a structure in which the leaving group can be removed by contact with an acid to form a hydrophilic group (e.g., hydroxy group or carboxy group), this is more noticeable. It is believed that there is.

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

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. The hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with 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. The hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group, or an alkoxy group having 1 to 12 carbon atoms.
R ^b4 and R ^b5 may bond to each other and 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 any integer from 0 to 5.
When m2 is 2 or more, multiple R ^b7s may be the same or different; when n2 is 2 or more, multiple R ^b8s 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 bond to each other and 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; The hydrogen atom contained in the aromatic hydrocarbon group may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group may be substituted with an alkoxy group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 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 is -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 any integer from 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 ^b13s are the same or different; when p2 is 2 or more, multiple R ^b14s are the same or different; when q2 is 2 or more, multiple R ^b15s are the same or different. , when r2 is 2 or more, multiple R ^b16s are the same or different; when s2 is 2 or more, multiple R ^b17s are the same or different; when t2 is 2 or more, multiple R ^b18s are the same or different; different.

特に、Ｒ^b9～Ｒ^b12の脂環式炭化水素基は、好ましくは炭素数３～１８、より好ましくは炭素数４～１２である。
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、ビフェニリル基、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、芳香族炭化水素基が、鎖式炭化水素基又は脂環式炭化水素基を有する場合は、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。 The aliphatic hydrocarbon group refers to a chain hydrocarbon group and an alicyclic hydrocarbon group.
Examples of 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. Can be mentioned.
In particular, the chain hydrocarbon groups R ^b9 to R ^b12 preferably have 1 to 12 carbon atoms.
The alicyclic hydrocarbon group may be monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclo Examples include cycloalkyl groups such as heptyl group, cyclooctyl group, and cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups.

In particular, the alicyclic hydrocarbon groups R ^b9 to R ^b12 preferably have 3 to 18 carbon atoms, more preferably 4 to 12 carbon atoms.
Examples of 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-isopropyladamantane-2-yl group, methylnorbornyl group, isobornyl group, and the like. In an alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group, the total number of carbon atoms in 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, biphenylyl group, naphthyl group, and phenanthryl group. 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 (tolyl group, xylyl group, cumenyl group, mesityl group) 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.).
In addition, when the aromatic hydrocarbon group has 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. is preferred.
Examples of the aromatic hydrocarbon group in which a hydrogen atom is substituted with an alkoxy group include p-methoxyphenyl group.
Examples of the chain hydrocarbon group in which a hydrogen atom is substituted with an aromatic hydrocarbon group include aralkyl groups such as benzyl group, phenethyl group, phenylpropyl group, trityl group, naphthylmethyl group, and naphthylethyl group.

Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group, and dodecyloxy group.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alkylcarbonyloxy group include methylcarbonyloxy group, ethylcarbonyloxy group, propylcarbonyloxy group, isopropylcarbonyloxy group, butylcarbonyloxy group, sec-butylcarbonyloxy group, tert-butylcarbonyloxy group, and pentylcarbonyloxy group. , hexylcarbonyloxy group, octylcarbonyloxy group, and 2-ethylhexylcarbonyloxy group.

Ｒ^b9とＲ^b10とが一緒になって形成する環は、単環式、多環式、芳香族性、非芳香族性、飽和及び不飽和のいずれの環であってもよい。この環は、３員環～１２員環が挙げられ、好ましくは３員環～７員環である。例えば、チオラン－１－イウム環（テトラヒドロチオフェニウム環）、チアン－１－イウム環、１，４－オキサチアン－４－イウム環等が挙げられる。
Ｒ^b11とＲ^b12とが一緒になって形成する環は、単環式、多環式、芳香族性、非芳香族性、飽和及び不飽和のいずれの環であってもよい。この環は、３員環～１２員環が挙げられ、好ましくは３員環～７員環である。オキソシクロヘプタン環、オキソシクロヘキサン環、オキソノルボルナン環、オキソアダマンタン環等が挙げられる。 The ring formed by R ^b4 and R ^b5 combined with each other and the sulfur atom to which they are bonded may be monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated. It may be a ring. Examples of this ring include a ring having 3 to 18 carbon atoms, preferably a ring having 4 to 18 carbon atoms. Further, examples of the ring containing a sulfur atom include a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring, such as the following rings. * represents a binding site.

The ring formed by R ^b9 and R ^b10 together may be monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated. Examples of this ring include a 3- to 12-membered ring, preferably a 3- to 7-membered ring. Examples include thiolane-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 monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated. Examples of this ring include a 3- to 12-membered ring, preferably a 3- to 7-membered ring. Examples include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

Among cations (b2-1) to cations (b2-4), 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.

Examples of the salt (I) include the salts listed in Table 1. For example, in Table 1, salt (I-1) is a salt consisting of an anion represented by formula (Ia-1) and a cation represented by formula (b2-c-1). be.

Among them, salt (I) includes salt (I-1) to salt (I-9), salt (I-16), salt (I-18) to salt (I-29), and salt (I-36). , Salt (I-38) ~ Salt (I-49), Salt (I-56), Salt (I-58) ~ Salt (I-69), Salt (I-76), Salt (I-78) ~ Salt (I-89), Salt (I-96), Salt (I-98) ~ Salt (I-109), Salt (I-116), Salt (I-118) ~ Salt (I-129), Salt (I-136), salt (I-138) ~ salt (I-149), salt (I-156), salt (I-158) ~ salt (I-169), salt (I-176), salt ( Preferred are salt (I-178) to salt (I-189), salt (I-196), salt (I-198) to salt (I-200), and salt (I-201) to salt (I-260).

（式中、全ての符号は、それぞれ前記と同じ意味を表す。Ｘは、ハロゲン原子又はＣＨ_３ＳＯ_４を表す。）
この反応における溶媒としては、クロロホルム、アセトニトリル、ジメチルホルムアミド等が挙げられる。
反応温度は通常５℃～８０℃であり、反応時間は通常０．５時間～２４時間である。 <Method for producing salt (I)>
Salt (I) can be produced, for example, by reacting a salt represented by formula (I-a) and a salt represented by formula (I1-b) in a solvent.

(In the formula, all symbols have the same meanings as above. X represents a halogen atom or CH ₃ SO _4. )
Examples of the solvent in this reaction include chloroform, acetonitrile, dimethylformamide, and the like.
The reaction temperature is usually 5°C to 80°C, and the reaction time is usually 0.5 to 24 hours.

Examples of the salt represented by formula (Ia) include salts represented by the following, which are easily available on the market.

（式中、全ての符号は、それぞれ前記と同じ意味を表す。）
この反応における溶媒としては、クロロホルム、アセトニトリル、ジメチルホルムアミド等が挙げられる。
反応温度は通常５℃～８０℃であり、反応時間は通常０．５時間～２４時間である。
式（Ｉ－ｃ）で表される塩は、例えば、以下で表される塩などが挙げられ、市場より容易に入手することができる。

式（Ｉ－ｄ）で表される化合物としては、下記式で表される化合物等が挙げられ、市場より容易に入手することができる。

The salt represented by the formula (I-b) can be prepared, for example, by reacting the salt represented by the formula (I-c) with carbonyldiimidazole in a solvent, and then reacting the salt represented by the formula (I-d) with the salt represented by the formula (I-d). It can be produced by reacting with the represented compound.

(In the formula, all symbols represent the same meanings as above.)
Examples of the solvent in this reaction include chloroform, acetonitrile, dimethylformamide, and the like.
The reaction temperature is usually 5°C to 80°C, and the reaction time is usually 0.5 to 24 hours.
Examples of the salt represented by formula (Ic) include salts represented by the following, and can be easily obtained from the market.

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

<Acid generator>
The acid generator of the present invention is an acid generator containing salt (I). Salt (I) may be used alone or in combination of two or more.
The acid generator of the present invention may contain, in addition to the salt (I), an acid generator known in the field of resists (hereinafter sometimes referred to as "acid generator (B)"). The acid generator (B) may be used alone or in combination of two or more.

The acid generator (B) may be either nonionic or ionic. Examples of nonionic acid generators include sulfonate esters (for example, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonate), sulfones (for example, disulfone, ketosulfone, sulfonyldiazomethane), etc. Typical ionic acid generators include onium salts containing onium cations (eg, diazonium salts, phosphonium salts, sulfonium salts, and iodonium salts). Examples of the anion of the onium salt include a sulfonic acid anion, a sulfonylimide anion, a sulfonylmethide anion, and the like.
As the acid generator (B), 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, U.S. Patent No. 3,779,778, U.S. Patent No. 3,849,137, German Patent No. 3914407, European Patent No. 126,712, etc. It is possible to use compounds that generate acids upon radiation as described in . 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 types.

［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。
Ｚ１^＋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)". However, salt (I ).

[In formula (B1),
Q ^b1 and Q ^b2 each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
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-. , the hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Y represents a methyl group which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and is included in the alicyclic hydrocarbon group. CH ₂ - may be replaced by -O-, -S(O) ₂ - or -CO-.
Z1 ⁺ 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 Examples include perfluorohexyl group.
Q ^b1 and Q ^b2 are each independently preferably a fluorine atom or a trifluoromethyl group, and more preferably both are fluorine atoms.

Examples of the divalent saturated hydrocarbon group in L ^b1 include a linear alkanediyl group, a branched alkanediyl group, and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group. It may also be a group formed by combining two or more of the groups.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1 ,7-diyl group, octane-1,8-diyl group, 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;
A monocyclic cycloalkanediyl group such as a cyclobutane-1,3-diyl group, a cyclopentane-1,3-diyl group, a cyclohexane-1,4-diyl group, or a cyclooctane-1,5-diyl group. alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbons such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, and adamantane-2,6-diyl group Examples include groups.
Examples of groups in which -CH ₂ - contained in the divalent saturated hydrocarbon group represented by L ^b1 are replaced with -O- or -CO- include formulas (b1-1) to (b1-3) Examples include groups represented by any of the following. 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 the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated -CH ₂ - contained in the hydrocarbon group may be replaced with -O- or -CO-.
However, the total carbon number 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 the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated -CH ₂ - contained in the hydrocarbon group may be replaced with -O- or -CO-.
However, the total carbon number 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 the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
L ^b7 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated -CH ₂ - contained in the hydrocarbon group may be replaced with -O- or -CO-.
However, the total carbon number 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-, the carbon before being replaced The number is the number of carbon atoms in the saturated hydrocarbon group.
Examples of the divalent saturated hydrocarbon group include those similar to the divalent saturated hydrocarbon group of L ^b1 .

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

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). Preferred groups are

［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。］ Examples of the group represented by formula (b1-1) include groups represented by formulas (b1-4) to (b1-8), respectively.

[In formula (b1-4),
L ^b8 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
In 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 the 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 the 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 the 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 the 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 divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b11 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b12 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b13 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b14 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b15 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b16 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 divalent saturated hydrocarbon group having 1 to 17 carbon atoms, more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.

式（ｂ１－９）中、
Ｌ^b19は、単結合又は炭素数１～２３の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b20は、単結合又は炭素数１～２３の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子、ヒドロキシ基又はア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。 Examples of the group represented by formula (b1-3) include groups represented by formulas (b1-9) to (b1-11), respectively.

In formula (b1-9),
L ^b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b20 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group 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 the 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 the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b22 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b23 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group 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 the 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 the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b25 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b26 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group 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 the 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, the substituted Let the previous carbon number be the carbon number of the saturated hydrocarbon group.

Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, a cyclohexylcarbonyloxy group, and an adamantylcarbonyloxy group.

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.

Examples of the alicyclic hydrocarbon group represented by Y include 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 one or two or more. good. Examples of 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）等の酸素原子を含む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 preferably includes formulas (Y1) to (Y20), formula (Y26), formula (Y27), formula (Y30), formula (Y31), and formula (Y39). 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), formula (Y31), formula (Y39), or formula (Y40), more preferably formula (Y11), formula (Y15), formula (Y20), formula (Y26), or formula (Y27), formula (Y30), formula (Y31), formula (Y39) or formula (Y40).
When the alicyclic hydrocarbon group represented by Y is a spiro ring containing an oxygen atom, such as formulas (Y28) to (Y35), formulas (Y39) to (Y40), between two oxygen atoms The alkanediyl group preferably has one or more fluorine atoms. Moreover, among the alkanediyl groups included in the ketal structure, it is preferable that the methylene group adjacent to the oxygen atom is not substituted with a fluorine atom.

Substituents for 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 an alkyl group having 1 to 16 carbon atoms, Represents an alicyclic hydrocarbon group, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof, and -CH ₂ - contained in the alkyl group and the alicyclic hydrocarbon group is -O- , -SO ₂ - or -CO-, and the hydrogen atom contained in the alkyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group is replaced with a hydroxy group or a fluorine atom. ja represents any integer from 0 to 4).
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 which may be substituted with 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 an alkyl group having 1 to 16 carbon atoms, Represents an alicyclic hydrocarbon group, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof, and -CH ₂ - contained in the alkyl group and the alicyclic hydrocarbon group is -O- , -SO ₂ - or -CO-, and the hydrogen atom contained in the alkyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group is replaced with a hydroxy group or a fluorine atom. ja represents any integer from 0 to 4).

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a norbornyl group, and an adamantyl group.
Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, naphthyl group, anthryl group, biphenyl group, and phenanthryl group. 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 (tolyl group, xylyl group, cumenyl group, mesityl group) 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.).
Examples of the alkyl group 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. group, decyl group, undecyl group, dodecyl group, etc.
Examples of the alkyl group substituted with a hydroxy group include hydroxyalkyl groups such as a hydroxymethyl group and a hydroxyethyl group.
Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group, and dodecyloxy group.
Examples of the aralkyl group include benzyl group, phenethyl group, phenylpropyl group, naphthylmethyl group, and naphthylethyl group.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, and a butyryl group.

Examples of Y include the following.

Y is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, more preferably an adamantyl group which may have a substituent; -CH ₂ - constituting the hydrogen group or 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.

Anions in the salt represented by formula (B1) include anions represented by formulas (B1-A-1) to (B1-A-55) [hereinafter referred to as "anion (B1-A-55)" according to the formula number. -1)” etc. ] is preferred, and formulas (B1-A-1) to (B1-A-4), formula (B1-A-9), formula (B1-A-10), and formulas (B1-A-24) to (B1-A-24) are preferred. (B1-A-33), Formula (B1-A-36) to Formula (B1-A-40), Formula (B1-A-47) to Formula (B1-A-55) Anions are more preferred.

ここでＲ^ｉ２～Ｒ^ｉ７は、それぞれ独立に、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。Ｒ^ｉ８は、例えば、炭素数１～１２の鎖式炭化水素基、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^Ａ４１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。
式（Ｂ１）で表される塩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 formed, for example, by a chain 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. and more preferably a methyl group, ethyl group, cyclohexyl group or adamantyl group. L ^A41 is a single bond or an alkanediyl group having 1 to 4 carbon atoms. Q ^b1 and Q ^b2 represent the same meanings as above.
Specific examples of the anion in the salt represented by formula (B1) include the anions described in JP-A No. 2010-204646.

Preferred anions in the salt represented by formula (B1) include anions represented by formulas (B1a-1) to (B1a-34), respectively.

Among them, formula (B1a-1) to formula (B1a-3), formula (B1a-7) to formula (B1a-16), formula (B1a-18), formula (B1a-19), formula (B1a-22 ) to (B1a-34) are preferred.

Examples of the organic cation of Z1 ⁺ include organic onium cations, organic sulfonium cations, organic iodonium cations, organic ammonium cations, benzothiazolium cations, and organic phosphonium cations. Among these, organic sulfonium cations and organic iodonium cations are preferred, and arylsulfonium cations are more preferred.
Examples of Z1 ⁺ in formula (B1) include the same ones as the cation (I) in salt (I).

The acid generator (B) is a combination of the above-mentioned anion and the above-mentioned organic cation, and these can be arbitrarily combined. The acid generator (B) is preferably one of formulas (B1a-1) to (B1a-3), formula (B1a-7) to (B1a-16), formula (B1a-18), and formula (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), among which those containing an arylsulfonium cation are preferred, and those containing formula (B1-1) ~ Formula (B1-3), Formula (B1-5) ~ Formula (B1-7), Formula (B1-11) ~ Formula (B1-14), Formula (B1-20) ~ Formula (B1-26), Particularly preferred are those represented by formula (B1-29) and formula (B1-31) to formula (B1-48).

When containing salt (I) and acid generator (B) as acid generators, the content ratio of salt (I) and acid generator (B) (mass ratio; salt (I): acid generator ( B)) is usually 1:99 to 99:1, preferably 2:98 to 98:2, more preferably 5:95 to 95:5, even more preferably 10:90 to 90. :10, particularly preferably 15:85 to 85:15.

<Resist composition>
The resist composition of the present invention contains an acid generator containing salt (I) and a resin having an acid-labile group (hereinafter sometimes referred to as "resin (A)"). Here, the term "acid-labile group" refers to a structure having a leaving group, which is removed by contact with an acid, and whose structural unit has a hydrophilic group (e.g., hydroxy group or carboxy group). means a group that is converted into a unit.
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 from the acid generator. , a solvent (hereinafter sometimes referred to as "solvent (E)") is preferably contained.

<Resin (A)>
The resin (A) has a structural unit (hereinafter sometimes referred to as "structural unit (a1)") having an acid-labile group. It is preferable that the resin (A) further contains a structural unit other than the structural unit (a1). Structural units other than structural unit (a1) include structural units that do not have acid-labile groups (hereinafter sometimes referred to as "structural units (s)"), structural units other than structural units (a1) and structural units (s) Structural units (for example, structural units having a halogen atom described below (hereinafter sometimes referred to as "structural unit (a4)"), structural units having a non-eliminating hydrocarbon group described later (hereinafter referred to as "structural unit (a5)") ) and other structural units derived from monomers known in the art.

［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 preferred.

[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 combination thereof. Watermelon, R ^a1 and R ^a2 combine with 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. Alternatively, R ^a2' and R ^a3' combine with 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 are included in the hydrocarbon group and the heterocyclic group - CH ₂ - may be replaced with -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 the alkyl group for R ^a1 , R ^a2 and R ^a3 include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group and the like.
The alicyclic hydrocarbon group in R ^a1 , R ^a2 and R ^a3 may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups (* represents a bond). The number of carbon atoms in the alicyclic hydrocarbon groups of R ^a1 , R ^a2 and R ^a3 is preferably 3 to 16.

Examples of groups combining an alkyl group and an alicyclic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, an adamantyldimethyl group, and a norbornyl group. Examples include ethyl group.
Preferably ma is 0 and na is 1.
Examples of --C(R ^a1 )(R ^a2 )(R ^a3 ) when R ^a1 and R ^a2 combine with each other to form an alicyclic hydrocarbon group include the following groups. The alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms. * represents a bond with -O-.

Ｒ^ａ１’及びＲ^ａ２’のうち、少なくとも１つは水素原子であることが好ましい。
ｎａ’は、好ましくは０である。 Examples of the hydrocarbon group for R ^a1' , R ^a2' and R ^a3' include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these.
Examples of the alkyl group and alicyclic hydrocarbon group 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 combining the above-mentioned alkyl group and an alicyclic hydrocarbon group, an aralkyl group such as a benzyl group, 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.), aromatic hydrocarbon group having alicyclic hydrocarbon group ( (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.), aryl-cycloalkyl groups such as phenylcyclohexyl group, and the like.
When R ^a2' and R ^a3' are bonded to each other to form a heterocyclic group together with the carbon atom to which they are bonded and X, -C(R ^a1' )(R ^a3' )-X-R ^a2' is, The following groups may be mentioned. * represents a bond.

It is preferable that at least one of R ^a1' and R ^a2' is a hydrogen atom.
na' is preferably 0.

Examples of the group (1) include the following groups.
A group in which R ^a1 , R ^a2 and R ^a3 are alkyl groups, ma=0, and na=1 in formula (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 atom to which they are bonded, R ^a3 is an alkyl group, ma=0, and na=1. .
In formula (1), R ^a1 and R ^a2 are each independently an alkyl group, R ^a3 is an adamantyl group, ma=0, and na=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.

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

［式（ａ１－０）、式（ａ１－１）及び式（ａ１－２）中、
Ｌ^a01、Ｌ^ａ１及びＬ^ａ２は、それぞれ独立に、－Ｏ－又は＊－Ｏ－（ＣＨ_２）_ｋ１－ＣＯ－Ｏ－を表し、ｋ１は１～７のいずれかの整数を表し、＊は－ＣＯ－との結合手を表す。
Ｒ^a01、Ｒ^ａ４及びＲ^ａ５は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^a02、Ｒ^a03及びＲ^a04は、それぞれ独立に、炭素数１～８のアルキル基、炭素数３～１８の脂環式炭化水素基又はこれらを組み合わせた基を表す。
Ｒ^ａ６及びＲ^ａ７は、それぞれ独立に、炭素数１～８のアルキル基、炭素数３～１８の脂環式炭化水素基又はこれらを組合せることにより形成される基を表す。
ｍ１は０～１４のいずれかの整数を表す。
ｎ１は０～１０のいずれかの整数を表す。
ｎ１’は０～３のいずれかの整数を表す。］ As a structural unit derived from a (meth)acrylic monomer having group (1), a structural unit represented by formula (a1-0) (hereinafter sometimes referred to as structural unit (a1-0)), a formula ( a1-1) (hereinafter sometimes referred to as structural unit (a1-1)) or the structural unit represented by formula (a1-2) (hereinafter referred to as structural unit (a1-2)) ) may be mentioned. Preferably, it is at least one structural unit selected from the group consisting of structural unit (a1-1) and structural unit (a1-2). These may be used alone or in combination of two or more.

[In formula (a1-0), formula (a1-1) and formula (a1-2),
L ^a01 , L ^a1 and L ^a2 each independently represent -O- or *-O-(CH ₂ ) _k1 -CO-O-, k1 represents any integer from 1 to 7, and * Represents a bond with -CO-.
R ^a01 , R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a02 , R ^a03 and R ^a04 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 ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group formed by combining these.
m1 represents any integer from 0 to 14.
n1 represents any integer from 0 to 10.
n1' represents any integer from 0 to 3. ]

R ^a01 , R ^a4 and R ^a5 are preferably methyl groups.
L ^a01 , L ^a1 and L ^a2 are preferably an oxygen atom or *-O-(CH ₂ ) _k01 -CO-O- (however, k01 is preferably an integer of 1 to 4, more preferably is 1), more preferably an oxygen atom.
Examples of the alkyl group, alicyclic hydrocarbon group, and a combination thereof in R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 include the groups listed for R ^a1 , R ^a2 and R ^a3 in formula (1). Examples include groups similar to .
The alkyl group in R ^a02 , R ^a03 , and R ^a04 preferably has 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.
The alkyl group in R ^a6 and R ^a7 preferably has 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group, or an isopropyl group, and even more preferably an ethyl group or an isopropyl group.
The number of carbon atoms in the alicyclic hydrocarbon groups of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 is preferably 5 to 12, more preferably 5 to 10.
In the group that is a combination of an alkyl group and an alicyclic hydrocarbon group, it is preferable that the total carbon number of the alkyl group and alicyclic hydrocarbon group is 18 or less.
R ^a02 and R ^a03 are preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group.
R ^a04 is preferably an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 5 to 12 carbon atoms, and more preferably a methyl group, ethyl group, cyclohexyl group or adamantyl group.
R ^a6 and R ^a7 are preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group, or an isopropyl group, and even more preferably an ethyl group or an isopropyl group.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1' is preferably 0 or 1.

The structural unit (a1-0) is, 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). Examples include structural units in which the corresponding methyl group is replaced with a hydrogen atom, and structural units represented by any of formulas (a1-0-1) to (a1-0-10) are preferred.

Examples of the structural unit (a1-1) include structural units derived from monomers described in JP-A No. 2010-204646. Among them, the structural unit represented by any one of formulas (a1-1-1) to formula (a1-1-4) and the methyl group corresponding to R ^a4 in the structural unit (a1-1) are replaced with a hydrogen atom. Structural units are preferred, and structural units represented by any of formulas (a1-1-1) to (a1-1-4) are more preferred.

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

When the resin (A) contains a structural unit (a1-0) and/or a structural unit (a1-1) and/or a structural unit (a1-2), the total content of these is the total structure of the resin (A). It is usually 10 to 95 mol%, preferably 15 to 90 mol%, more preferably 20 to 85 mol%, even more preferably 25 to 80 mol%, and even more preferably It is 30 to 75 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。］ Examples of the structural unit having a group (2) in the structural unit (a1) include a structural unit 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 that may have a halogen atom.
R ^a33 is a halogen atom, hydroxy group, alkyl group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms, alkylcarbonyl group having 2 to 4 carbon atoms, alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl Represents an oxy group or a methacryloyloxy group.
la represents any integer from 0 to 4. When la is 2 or more, a plurality of R ^a33 's 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, and 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 divalent hydrocarbon group having 2 to 20 carbon atoms together with the -C-O- to which they are bonded, and the -CH ₂ - contained in the hydrocarbon group and the divalent hydrocarbon group is - May be replaced with O- or -S-. ]

Examples of the alkyl group for R ^a32 and R ^a33 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, and a 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, and even more preferably a methyl group.
Examples of the halogen atom for R ^a32 and R ^a33 include a fluorine atom, a chlorine atom, and a bromine atom.
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. Can be mentioned.
Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group and hexyloxy group. Among these, 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.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, and the like.
Examples of the hydrocarbon group in R ^a34 , R ^a35 and R ^a36 include an alkyl group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group, and the same groups as R ^a1' and R ^a2' in formula (2) can be mentioned. 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 a combination thereof. can be 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, and more preferably 0.
R ^a34 is preferably a hydrogen atom.
R ^a35 is preferably an alkyl group or an alicyclic hydrocarbon group having 1 to 12 carbon atoms, 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 thereof. More preferably, it is an alkyl group having 1 to 18 carbon atoms, an alicyclic aliphatic 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 having 6 to 10 carbon atoms.

--OC(R ^a34 )(R ^a35 )-O-R ^a36 in structural unit (a1-4) comes into contact with an acid (for example, p-toluenesulfonic acid) and is eliminated to form a hydroxy group.

Examples of the structural unit (a1-4) include structural units derived from monomers described in JP-A No. 2010-204646. Preferred examples include structural units represented by formulas (a1-4-1) to (a1-4-12), respectively, and structural units in which the hydrogen atom corresponding to R ^a32 is replaced with a methyl group, and more preferably , the structural units represented by formulas (a1-4-1) to (a1-4-5), and formula (a1-4-10), respectively.

When the resin (A) has a structural unit (a1-4), its content is preferably 10 to 95 mol%, and 15 to 90% by mole based on the total of all structural units of the resin (A). It is more preferably mol%, even more preferably 20 to 85 mol%, even more preferably 20 to 70 mol%, and particularly preferably 20 to 60 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。 Examples of the structural unit derived from the (meth)acrylic monomer having group (2) include the structural unit represented by formula (a1-5) (hereinafter sometimes referred to as "structural unit (a1-5)"). It will 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 an integer of 1 to 3.
s1' represents any integer from 0 to 3.

Examples of the halogen atom include a fluorine atom and a chlorine atom, with a fluorine atom being preferred.
Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, fluoromethyl group, and trifluoromethyl group. Examples include 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.
It is preferable that one of L ⁵² and L ⁵³ is -O- and the other is -S-.
s1 is preferably 1.
s1' is preferably an integer of 0 to 2.
Z ^a1 is preferably a single bond or *-CH ₂ -CO-O-.

Examples of the structural unit (a1-5) include structural units derived from monomers described in JP-A No. 2010-61117. Among these, structural units represented by formulas (a1-5-1) to (a1-5-4), respectively, are preferred, and structural units represented by formula (a1-5-1) or formula (a1-5-2) are preferred. Structural units are more preferred.

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

Moreover, as the structural unit (a1), the following structural units may also be mentioned.

When the resin (A) contains structural units such as (a1-3-1) to (a1-3-7) above, the content thereof is 10 to 10% of the total structural units of the resin (A). 95 mol% is preferred, 15 to 90 mol% is more preferred, 20 to 85 mol% is even more preferred, 20 to 70 mol% is even more preferred, 20 to 60 mol% is even more preferred, and 10 to 40 mol% is Particularly preferred.

<Structural unit (s)>
The structural unit (s) is derived from a monomer that does not have an acid-labile group (hereinafter sometimes referred to as "monomer (s)"). As the monomer leading to the structural unit (s), monomers having no acid-labile groups 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 not having an acid-labile group (hereinafter sometimes referred to as "structural unit (a2)") and/or a structure having a lactone ring and not having an acid-labile group By using a resin having the unit (hereinafter sometimes referred to as "structural unit (a3)") in the resist composition of the present invention, the resolution of the resist pattern and the adhesion to the substrate can be improved.

<Structural unit (a2)>
The hydroxy group that the structural unit (a2) has may be an alcoholic hydroxy group or a phenolic hydroxy group.
When producing a resist pattern from the resist composition of the present invention, when a high-energy beam such as a KrF excimer laser (248 nm), an electron beam, or EUV (ultra-ultraviolet light) is used as an exposure light source, the structural unit (a2) is It is preferable to use a structural unit (a2) having a phenolic hydroxy group. Furthermore, when using an ArF excimer laser (193 nm), etc., the structural unit (a2) is preferably a structural unit (a2) having an alcoholic hydroxy group, and it is more preferable to use the structural unit (a2-1) described below. preferable. The structural unit (a2) may contain one type alone or two or more types.

［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。］ Examples of the structural unit having a phenolic hydroxy group in the structural unit (a2) include a structural unit represented by formula (a2-A) (hereinafter sometimes referred to as "structural unit (a2-A)").

[In 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, hydroxy group, alkyl group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms, alkylcarbonyl group having 2 to 4 carbon atoms, alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl 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 is bonded.
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 any integer from 0 to 4. When mb is any integer of 2 or more, a plurality of R ^a51 's may be the same or different. ]

Examples of the halogen atom for R ^a50 include a fluorine atom, a chlorine atom, a bromine atom, and the like.
Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom in 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 group Examples include 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, and even more preferably a hydrogen atom or a methyl group.
Examples of the alkyl group for R ^a51 include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, and hexyl group.
Examples of the alkoxy group for R ^a51 include methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, sec-butoxy group, and tert-butoxy group. 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.
Examples of the alkylcarbonyl group for R ^a51 include an acetyl group, a propionyl group, a butyryl group, and the like.
Examples of the alkylcarbonyloxy group for R ^a51 include 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 -. Among these, *-CO-O-, *-CO-O-A ^a52 -CO-O-, or *-O-A ^a52 -CO-O- is preferred.

Examples of alkanediyl groups include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, and hexane-1,5-diyl group. 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 -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-, and is preferably 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 ortho or para position of the benzene ring, and more preferably to the para position.

Structural units (a2-A) include 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. The structural unit (a2-A) is a structural unit represented by formula (a2-2-1), a structural unit represented by formula (a2-2-3), or a structural unit represented by formula (a2-2-6). In 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), It is preferable that the structural unit (a2-A) is a structural unit in which the methyl group corresponding to R ^a50 is replaced with a hydrogen atom.

When the structural unit (a2-A) is contained in the resin (A), the content of the structural unit (a2-A) is preferably 5 to 80 mol%, more preferably 5 to 80 mol% based on the total structural units. The content is 10 to 70 mol%, more preferably 15 to 65 mol%, even more preferably 20 to 65 mol%, and even more preferably 20 to 50 mol%.
The structural unit (a2-A) can be incorporated into the resin (A) by, for example, polymerizing the structural unit (a1-4) and then treating it 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.

式（ａ２－１）中、
Ｌ^a3は、－Ｏ－又は＊－Ｏ－（ＣＨ₂）_k2－ＣＯ－Ｏ－を表し、
ｋ２は１～７のいずれかの整数を表す。＊は－ＣＯ－との結合手を表す。
Ｒ^a14は、水素原子又はメチル基を表す。
Ｒ^a15及びＲ^a16は、それぞれ独立に、水素原子、メチル基又はヒドロキシ基を表す。
ｏ１は、０～１０のいずれかの整数を表す。 Examples of the structural unit having an alcoholic hydroxy group in the structural unit (a2) include 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 any integer from 0 to 10.

In formula (a2-1), L ^a3 is preferably -O-, -O-(CH ₂ ) _f1 -CO-O- (the f1 represents any integer from 1 to 4). , more preferably -O-.
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, more preferably 0 or 1.

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

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). It is more preferably 1 to 35 mol%, still more preferably 1 to 20 mol%, and even more preferably 1 to 10 mol%.

<Structural unit (a3)>
The lactone ring possessed by the structural unit (a3) may be a monocyclic ring such as a β-propiolactone ring, a γ-butyrolactone ring, or a δ-valerolactone ring, or may be a fused ring of a monocyclic lactone ring and another ring. But that's fine. Preferred examples include a γ-butyrolactone ring, an adamantane lactone ring, or a bridged ring containing a γ-butyrolactone ring structure (for example, a structural unit represented by the following formula (a3-2)).

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

[In formula (a3-1), formula (a3-2), formula (a3-3) and formula (a3-4),
L ^a4 , L ^a5 and L ^a6 are each independently represented by -O- or *-O-(CH ₂ ) _k3 -CO-O- (k3 represents any integer from 1 to 7); represents a group.
L ^a7 is -O-, *-OL ^a8 -O-, *-OL ^a8 -CO-O-, *-OL ^a8 -CO-OL ^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 any integer from 0 to 3.
r1 represents any integer from 0 to 3.
w1 represents any integer from 0 to 8.
When p1, q1, r1 and/or w1 is 2 or more, the plurality of R ^a21 , R ^a22 , R ^a23 and/or R ^a25 may be the same or different. ]

Examples of the aliphatic hydrocarbon groups 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. It will be done.
Examples of the halogen atom in R ^a24 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alkyl group in 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. Examples include alkyl groups, more preferably methyl groups or ethyl groups.
Examples of the alkyl group having a halogen atom in R ^a24 include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluoro sec-butyl group, perfluoro tert-butyl group, perfluoropentyl group, perfluoro Examples include hexyl group, trichloromethyl group, tribromomethyl group, triiodomethyl group, and the like.
Examples of the alkanediyl group in L ^a8 and L ^a9 include 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, Examples include 4-diyl group and 2-methylbutane-1,4-diyl group.

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-, even 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, and even more preferably a hydrogen atom or a methyl group. It 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 of 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 represent the same meanings as above.)

As the structural unit (a3), structures derived from monomers described in JP-A No. 2010-204646, monomers described in JP-A No. 2000-122294, and monomers described in JP-A No. 2012-41274 can be used. Units are listed. 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 formula (a3-3-2) and any one of formulas (a3-4-1) to formula (a3-4-12), and in the structural unit, formula (a3-1 ) ~ Structural units in which the methyl groups corresponding to R ^a18 , R ^a19 , R ^a20 and R ^a24 in formula (a3-4) are replaced with hydrogen atoms are preferred.

When the resin (A) contains the structural unit (a3), the total content thereof is usually 1 to 70 mol%, preferably 1 to 65 mol%, based on the total structural units of the resin (A). , more preferably 1 to 60 mol%.
In addition, the content of the structural unit (a3-1), the structural unit (a3-2), the structural unit (a3-3), or the structural unit (a3-4) is relative to the total structural units of the resin (A), respectively. The amount is preferably 1 to 60 mol%, more preferably 1 to 50 mol%, and even more preferably 1 to 50 mol%.

［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)>
Examples of the structural unit (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 carbon atoms and having a fluorine atom, and -CH ₂ - contained in the saturated hydrocarbon group may be replaced with -O- or -CO. ]
Examples of the saturated hydrocarbon group represented by R ⁴² include a chain hydrocarbon group, a monocyclic or polycyclic alicyclic hydrocarbon group, and a group formed by combining these.

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 chain 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. Can be mentioned. Examples of monocyclic or polycyclic alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group, and cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups. Examples include polycyclic alicyclic hydrocarbon groups such as (* represents a bond).

Examples of the group formed by the combination include a group formed by combining one or more alkyl groups or one or more alkanediyl groups and one or more alicyclic hydrocarbon groups, such as -alkanediyl group- Examples include alicyclic hydrocarbon group, -alicyclic hydrocarbon group-alkyl group, -alkanediyl group-alicyclic hydrocarbon group-alkyl group, and the like.

［式（ａ４－０）中、
Ｒ⁵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２価の脂肪族飽和炭化水素基を表す。
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。
Ｒ⁶は、水素原子又はフッ素原子を表す。］ The structural unit (a4) is at least one selected from the group consisting of formula (a4-0), formula (a4-1), formula (a4-2), formula (a4-3) and formula (a4-4). Examples include structural units represented by one.

[In formula (a4-0),
R ⁵ represents a hydrogen atom or a methyl group.
L ^4a represents a single bond or a divalent aliphatic saturated hydrocarbon 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 ⁶ represents a hydrogen atom or a fluorine atom. ]

Examples of the divalent aliphatic saturated hydrocarbon group in L ^4a include linear alkanediyl groups such as methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, and ethane-1 , 1-diyl group, propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, and 2-methylpropane-1,2-diyl group, etc. and alkanediyl groups.
The perfluoroalkanediyl group in 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.
Examples of the perfluorocycloalkanediyl group for L ^3a include 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 perfluoroalkanediyl group having 1 to 6 carbon atoms, more preferably a perfluoroalkanediyl group having 1 to 3 carbon atoms.

Examples of the structural unit (a4-0) include the structural units shown below and structural units in which the methyl group corresponding to R ⁵ 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 a saturated hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and -CH ₂ - contained in the saturated hydrocarbon group is replaced with -O- or -CO-. You can.
A ^a41 represents an alkanediyl group having 1 to 6 carbon atoms which may have a substituent 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 formula (a-g1),
s represents 0 or 1.
A ^a42 and A ^a44 each independently represent a divalent saturated hydrocarbon group having 1 to 5 carbon atoms which may have a substituent.
A ^a43 represents a divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a single bond or a substituent.
X ^a41 and X ^a42 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 the * 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以上の脂環式飽和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－脂環式飽和炭化水素基、－脂環式飽和炭化水素基－アルキル基、－アルカンジイル基－脂環式飽和炭化水素基－アルキル基等が挙げられる。 Examples of the saturated hydrocarbon group for R ^a42 include a chain saturated hydrocarbon group, a monocyclic or polycyclic alicyclic saturated hydrocarbon group, and a group formed by combining these.
Examples of 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. can be mentioned.
Examples of monocyclic or polycyclic alicyclic saturated hydrocarbon groups include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group, and cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group, and the following. Examples include polycyclic alicyclic saturated hydrocarbon groups such as groups (* represents a bond).

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

［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。 Examples of the substituent that R ^a42 may have include at least one selected from the group consisting of a halogen atom and a group represented by formula (a-g3). Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred.

[In 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.

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。 The aliphatic hydrocarbon groups in A ^a45 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 Alkyl groups such as octadecyl groups;
Monocyclic alicyclic hydrocarbon groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group; and decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* represents a bond) ) and other polycyclic alicyclic hydrocarbon groups.

Examples of the group formed by the combination include a group formed by combining one or more alkyl groups or one or more alkanediyl groups and one or more alicyclic hydrocarbon groups, such as -alkanediyl group- Examples thereof include alicyclic hydrocarbon group, -alicyclic hydrocarbon group-alkyl group, and -alkanediyl group-alicyclic hydrocarbon group-alkyl group.

R ^a42 is preferably an aliphatic hydrocarbon group which may have a halogen atom, more preferably an aliphatic hydrocarbon group having an alkyl group having a halogen atom and/or a group represented by formula (a-g3) .
When R ^a42 is an aliphatic hydrocarbon group having a halogen atom, it is preferably an aliphatic hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, and even more preferably a carbon number A perfluoroalkyl group having 1 to 6 carbon atoms, particularly preferably a perfluoroalkyl group having 1 to 3 carbon atoms. Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, and a perfluorooctyl group. Examples of the perfluorocycloalkyl group include a perfluorocyclohexyl group.
When R ^a42 is an aliphatic hydrocarbon group having a group represented by formula (a-g3), the total number of R ^a42 including the number of carbon atoms contained in the group represented by formula (a-g3) The number of carbon atoms is preferably 15 or less, more preferably 12 or less. When having 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価の脂肪族炭化水素基を表す。
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 an aliphatic hydrocarbon having a group represented by formula (a-g3), R ^a42 is more preferably a group represented by formula (a-g2).

[In formula (a-g2),
A ^a46 represents a divalent aliphatic 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 aliphatic hydrocarbon group of A ^a46 preferably has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms.
The aliphatic hydrocarbon group of A ^a47 preferably has 4 to 15 carbon atoms, more preferably 5 to 12 carbon atoms, and A ^a47 is more preferably a cyclohexyl group or an adamantyl group.

A preferable structure of the group represented by formula (a-g2) is the following structure (* is a bond with a carbonyl group).

As the alkanediyl group in A ^a41 , methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group Straight chain alkanediyl groups such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,2-diyl group, 1-methylbutane-1,4-diyl group, Examples include branched alkanediyl groups such as 2-methylbutane-1,4-diyl group.
Examples of the substituent 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 even 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 divalent alicyclic groups. Examples include a hydrocarbon group and a group 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, Examples include 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.
Examples of substituents for the divalent saturated hydrocarbon group represented by A ^a42 , A ^a43 and A ^a44 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
Preferably, s is 0.

Examples of the group represented by formula (a-g1) 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 methyl group corresponding to R ^a41 in the structural unit shown below and the structural unit represented by formula (a4-1) in the following structural unit is a hydrogen atom. Examples include substituted structural units.

［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。］ The structural unit represented by formula (a4-1) is preferably a structural unit represented by formula (a4-2).

[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 having a fluorine atom.
However, the upper limit of the total number of carbon atoms in L ⁴⁴ and R ^f6 is 21. ]

Examples of the alkanediyl group having 1 to 6 carbon atoms in L ⁴⁴ include the same groups as those exemplified for the alkanediyl group in A ^a41 .
Examples of the saturated hydrocarbon group for R ^f6 include the same groups as exemplified for R ^a42 .
The alkanediyl group having 1 to 6 carbon atoms in L ⁴⁴ is preferably an alkanediyl group having 2 to 4 carbon atoms, and more preferably an ethylene group.

Examples of the structural unit represented by formula (a4-2) include structural units represented by formulas (a4-1-1) to (a4-1-11), respectively. A structural unit in which the methyl group corresponding to R ^f5 in structural unit (a4-2) is replaced with a hydrogen atom is also included as the structural unit represented by 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。］ Examples of the structural unit (a4) include a structural unit represented by formula (a4-3).

[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 divalent saturated hydrocarbon group having 1 to 18 carbon atoms which may have a fluorine atom.
X ^f12 represents *-O-CO- or *-CO-O- (* represents a bond with A ^f13 ).
A ^f14 represents a saturated hydrocarbon group having 1 to 17 carbon atoms 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 number of carbon atoms in L ⁵ , A ^f13 and A ^f14 is 20. ]

Examples of the alkanediyl group for L ⁵ include the same groups as those exemplified for the alkanediyl group for A ^a41 .
The divalent saturated hydrocarbon group which may have a fluorine atom in A ^f13 is preferably a divalent aliphatic saturated hydrocarbon group which may have a fluorine atom and a divalent saturated hydrocarbon group which may have a fluorine atom. A divalent alicyclic saturated hydrocarbon group is preferable, and a perfluoroalkanediyl group is more preferable.
Examples of the divalent aliphatic hydrocarbon group which may have a fluorine atom include alkanediyl groups such as methylene group, ethylene group, propanediyl group, butanediyl group and pentanediyl group; difluoromethylene group, perfluoroethylene group, perfluoroethylene group, etc. Examples include 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. Examples of the monocyclic group include a cyclohexanediyl group and a perfluorocyclohexanediyl group. Examples of the polycyclic group include an adamantanediyl group, a norbornanediyl group, and a perfluoroadamantanediyl group.
Examples of the saturated hydrocarbon group of A ^f14 and the saturated hydrocarbon group which may have a fluorine atom include the same groups as 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 of 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group, heptyl group, perfluoroheptyl group, octyl group, perfluorooctyl group, etc. 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 , perfluoroadamantylmethyl group, etc. are preferred.

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; More preferred are two to three divalent chain hydrocarbon groups.
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 these, A ^f14 is preferably a group containing an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a cyclopropylmethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group.

Examples of the structural unit represented by formula (a4-3) include structural units represented by formulas (a4-1'-1) to (a4-1'-11), respectively. A structural unit in which the methyl group corresponding to R ^f7 in structural unit (a4-3) is replaced with a hydrogen atom is also included as a structural unit represented by 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。］ The structural unit (a4) also includes a structural unit 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 saturated hydrocarbon group having 1 to 10 carbon atoms and having a fluorine atom. ]

Examples of the saturated hydrocarbon group for R ^f22 include the same saturated hydrocarbon group as the 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. Preferably, an alkyl group having 1 to 6 carbon atoms and having a fluorine atom is more preferable.

In formula (a4-4), A ^f21 is preferably -(CH ₂ ) _j1 -, more preferably an ethylene group or a methylene group, and even more preferably a methylene group.

As the structural unit represented by formula (a4-4), for example, in the following structural units and the structural unit represented by the following formula, the methyl group corresponding to R ^f21 in structural unit (a4-4) is hydrogen. Examples include structural units that replace atoms.

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

［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 the non-eliminating hydrocarbon group possessed by the structural unit (a5) include groups having a linear, branched or cyclic hydrocarbon group. Among these, the structural unit (a5) is preferably a group having an alicyclic hydrocarbon group.
Examples of the structural unit (a5) include a structural unit represented by formula (a5-1).

[In formula (a5-1),
R ⁵¹ represents a hydrogen atom or a methyl group.
R ⁵² represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms. .
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 the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the polycyclic alicyclic hydrocarbon group include an adamantyl group and a norbornyl group.
Examples of aliphatic hydrocarbon groups having 1 to 8 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group, and - Alkyl groups such as ethylhexyl group.
Examples of the alicyclic hydrocarbon group having a substituent include a 3-methyladamantyl group.
R ⁵² is preferably an unsubstituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, more preferably an adamantyl group, norbornyl group or cyclohexyl group.
Examples of the divalent saturated hydrocarbon group in L ⁵⁵ include a divalent chain saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, and preferably a divalent chain saturated hydrocarbon group. .
Examples of the divalent chain saturated hydrocarbon group include alkanediyl groups such as methylene group, ethylene group, propanediyl group, butanediyl group, and pentanediyl group.
The divalent alicyclic saturated hydrocarbon group may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic saturated hydrocarbon group include 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。 Examples of groups in which -CH ₂ - contained in the divalent saturated hydrocarbon group represented by L ⁵⁵ are replaced with -O- or -CO- include formulas (L1-1) to (L1-4). The groups represented can be mentioned. In the following formula, * 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 represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms.
W ^x1 represents a divalent alicyclic saturated 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 divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group.
L ^x2 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond.
L ^x3 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x4 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x5 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group.
L ^x6 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group.
L ^x7 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x8 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond or a methylene group.
L ^x9 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond or a methylene group.
W ^x1 is preferably a divalent alicyclic saturated 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 following divalent groups.

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 a structural unit (a5), its content is preferably 1 to 30 mol%, more preferably 2 to 20 mol%, and 3 to 30 mol%, based on the total structural units of the resin (A). More preferably 15 mol%.

<Structural unit (II)>
The resin (A) may further contain a structural unit (hereinafter sometimes referred to as "structural unit (II)") that decomposes upon exposure to generate an acid. Specific examples of the structural unit (II) include the structural unit described in JP-A-2016-79235, which includes 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 sulfonate group or a carboxylate group in the side chain. A structural unit having a group and an organic anion is preferable.

［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。］ The structural unit having a sulfonate group or carboxylate group in its side chain is preferably a structural unit represented by formula (II-2-A').

[In 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-. Often, the 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 contain a halogen atom, or a hydroxy group.
A ^x1 represents an alkanediyl group having 1 to 8 carbon atoms, and the 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. ]

Examples of the halogen atom represented by R ^III3 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
The alkyl group having 1 to 6 carbon atoms and optionally having a halogen atom represented by R ^III3 includes the alkyl group having 1 to 6 carbon atoms optionally having a halogen atom represented by R ^a8 ; The same thing can be mentioned.
The alkanediyl group having 1 to 8 carbon atoms represented by A ^x1 includes a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, and a 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. Can be mentioned.
Examples of the perfluoroalkyl group having 1 to 6 carbon atoms which may be substituted with A ^x1 include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert group. -butyl group, perfluoropentyl group, perfluorohexyl group, etc.
Examples of the divalent saturated hydrocarbon group having 1 to 18 carbon atoms represented by ^XIII3 include a linear or branched alkanediyl group, and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group. or a combination of these may be used.
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 , linear alkanediyl groups such as dodecane-1,12-diyl group; butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group , pentane-1,4-diyl group, branched alkanediyl group such as 2-methylbutane-1,4-diyl group; 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 Examples include divalent polycyclic alicyclic saturated hydrocarbon groups such as -2,6-diyl group.
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). Can be mentioned. However, the number of carbon atoms in each of the saturated hydrocarbon groups before --CH ₂ -- is replaced with --O-, --S-, or --CO- is 17 or less. In the following formula, * and ** represent a binding site, 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.

Examples of ZA ⁺ in formula (II-2-A') include the same cation Z ⁺ in salt (I).

［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、前述の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 any integer from 0 to 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 as each other; It may be different or it may be different.
Q ^a and Q ^b each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. ]
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 group having 1 to 6 carbon atoms represented by Q ^b1 described above. .

［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。］
Ｒ^ＩＩＩ５で表される炭素数１～１２の飽和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、ヘプチル基、オクチル基、ノニル基、デシル基、ウンデシル基及びドデシル基等の直鎖又は分岐のアルキル基が挙げられる。
Ｘ^Ｉ２で表される２価の飽和炭化水素基としては、Ｘ^ＩＩＩ３で表される２価の飽和炭化水素基と同様のものが挙げられる。 The structural unit represented by formula (II-2-A) is preferably a structural unit represented by formula (II-2-A-1).

[In formula (II-2-A-1),
R ^III2 , R ^III3 , R ^III4 , Q ^a , Q ^b and ZA ⁺ represent the same meanings as above.
R ^III5 represents a saturated hydrocarbon group having 1 to 12 carbon atoms.
z2A1 represents any integer from 0 to 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-. Often, the hydrogen atoms contained in the saturated hydrocarbon group may be substituted with a halogen atom or a hydroxy group. ]
The saturated hydrocarbon group having 1 to 12 carbon atoms represented by R ^III5 includes methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, Straight chain or branched alkyl groups such as heptyl group, octyl group, nonyl group, decyl group, undecyl group and dodecyl group are mentioned.
Examples of the divalent saturated hydrocarbon group represented by X ^I2 include those similar to the divalent saturated hydrocarbon group represented by X ^III3 .

［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、それぞれ独立に、１又は２を表す。］ As the structural unit represented by formula (II-2-A-1), a structural unit represented by formula (II-2-A-2) is more 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. ]

Examples of the structural unit represented by formula (II-2-A') include the following structural units and the 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。具体的には、Ｒ^a1’、Ｒ^a2’及びＲ^a3’における炭化水素基と同じものが挙げられる。
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。 The structural unit having a sulfonio group and an organic anion in its side chain is preferably a structural unit represented by formula (II-1-1).

[In formula (II-1-1),
A ^II1 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 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.
Examples of the hydrocarbon group represented by R ^II2 and R ^II3 include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these. Specifically, the same hydrocarbon groups as R ^a1' , R ^a2' and R ^a3' can be mentioned.
Examples of the halogen atom represented by R ^II4 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
The alkyl group having 1 to 6 carbon atoms and optionally having a halogen atom represented by R ^II4 includes the alkyl group having 1 to 6 carbon atoms optionally having a halogen atom represented by R ^a8 ; The same thing can be mentioned.
Examples of the divalent linking group represented by A ^II1 include a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and -CH ₂ - contained in the divalent saturated hydrocarbon group is It may be replaced with -O-, -S- or -CO-. Specifically, the same divalent saturated hydrocarbon group having 1 to 18 carbon atoms as represented by ^XIII3 can be mentioned.

Examples of the cation-containing structural unit in formula (II-1-1) include the structural units shown below.

Examples of the organic anion represented by A ^- include sulfonic acid anions, sulfonylimide anions, sulfonylmethide anions, and carboxylic acid anions. The organic anion represented by A ^- is preferably a sulfonate anion, and the sulfonate anion is more preferably an anion contained in the salt represented by the above-mentioned formula (B1).

Examples of the sulfonylimide anion represented by A ^- include the following.

Examples of sulfonyl methide anions include the following.

Examples of carboxylic acid anions include the following.

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

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

The resin (A) may have structural units other than the above-mentioned structural units, and examples of such structural units include structural units well known in the art.

The resin (A) is preferably a resin consisting of a structural unit (a1) and a structural unit (s), that is, a copolymer of a monomer (a1) and a monomer (s).
Structural unit (a1) preferably includes structural unit (a1-0), structural unit (a1-1), structural unit (a1-2) (preferably the structural unit having a cyclohexyl group and a cyclopentyl group), and the structural unit At least one type selected from the group consisting of (a1-4), more preferably at least two types, still more preferably selected from the group consisting of structural unit (a1-1) and structural unit (a1-2) There are at least two types.
The structural unit (s) is preferably at least one selected from the group consisting of the structural unit (a2) and the structural unit (a3). Structural unit (a2) is preferably structural unit (a2-1) or structural unit (a2-A). Structural unit (a3) is preferably a group consisting of a structural unit represented by formula (a3-1), a structural unit represented by formula (a3-2), and a structural unit represented by formula (a3-4). At least one type selected from
Each structural unit constituting the resin (A) may be used alone or in combination of two or more, and is produced by a known polymerization method (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, even more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less, even more preferably 15,000 or less). In this specification, the weight average molecular weight is a value determined by gel permeation chromatography under the conditions described in Examples.

<Resin other than resin (A)>
The resist composition of the present invention may further contain a resin other than resin (A).
Examples of resins other than resin (A) include resins containing structural unit (a4) or structural unit (a5) (hereinafter sometimes referred to as resin (X)).
Among the resins (X), resins containing the structural unit (a4) are preferred. In other words, a resin containing a structural unit having a fluorine atom is preferable.
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 include structural units (a1), structural units (a2), structural units (a3), and structural units derived from other known monomers. Among these, the resin (X) is preferably a resin consisting only of the structural unit (a4) and/or the structural unit (a5).
Each structural unit constituting the resin (X) may be used alone or in combination of two or more, and can be produced by a known polymerization method (for example, radical polymerization method) using a monomer that induces these structural units. can do. The content of each structural unit in the resin (X) can be adjusted by adjusting the amount of monomer used for polymerization.
The weight average molecular weight of the resin (X) is preferably 6,000 or more (more preferably 7,000 or more) and 80,000 or less (more preferably 60,000 or less). The means for measuring the weight average molecular weight of resin (X) is the same as that for resin (A).

When the resist composition of the present invention contains resin (X), the content thereof is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, based on 100 parts by mass of resin (A). It is more preferably 1 to 40 parts by weight, particularly preferably 1 to 30 parts by weight, particularly preferably 1 to 8 parts by weight.

The content of the resin (A) in the resist composition is preferably 75% by mass or more and 99% by mass or less, more preferably 80% by mass or more and 95% by mass or less, based on the solid content of the resist composition. In addition, 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 75% by mass or more and 99% by mass based on the solid content of the resist composition. It is preferably at most 80% by mass and at most 95% by mass. The solid content of the resist composition and the resin content relative to the solid content can be measured by known analytical means such as liquid chromatography or gas chromatography.

<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, and 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, ethyl pyruvate, etc. Ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; Cyclic esters such as γ-butyrolactone; and the like. One type of solvent (E) may be used alone, or two or more types may be used.

<Quencher (C)>
Examples of the quencher (C) include salts that generate an acid that is weaker in acidity than the acid generated from the basic nitrogen-containing organic compound and the acid generator (B). 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.
Basic nitrogen-containing organic compounds include amines and ammonium salts. Amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines.
Examples of 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, 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, etc. Preferably, aromatic amines such as diisopropylaniline are used, and 2,6-diisopropylaniline is more preferable.
Examples of ammonium salts include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3-(trifluoromethyl)phenyltrimethyl Examples include ammonium hydroxide, tetra-n-butylammonium salicylate, and choline.

The acidity of a salt that generates an acid with weaker acidity than the acid generated from the acid generator (B) is indicated by the acid dissociation constant (pKa). The salt that generates an acid with weaker acidity than the acid generated from the acid generator (B) is a salt in which the acid dissociation constant of the acid generated from the salt is usually -3<pKa, preferably -1<pKa. A salt with a pKa<7, more preferably a salt with a pKa<5.
Examples of the salt that generates an acid with weaker acidity than the acid generated from the acid generator (B) include a salt represented by the following formula, a salt represented by the formula (D) described in JP-A-2015-147926; (hereinafter sometimes referred to as "weak acid inner salt (D)"), as well as JP 2012-229206, JP 2012-6908, JP 2012-72109, and JP 2011-39502. Examples include salts described in publications and JP-A No. 2011-191745. A weak acid inner salt (D) is preferable as a salt that generates an acid with weaker acidity than the acid generated from the acid generator (B).

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

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

<Preparation of resist composition>
The resist composition of the present invention comprises a salt (I), a resin (A), and, if necessary, an acid generator (B), a resin other than the resin (A), a solvent (E), a quencher (C) and It can be prepared by mixing other components (F). The mixing order is arbitrary and is not particularly limited. An appropriate temperature for mixing can be 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 it using a filter with a pore size of about 0.003 to 0.2 μm.

<Resist pattern manufacturing method>
The method for manufacturing a resist pattern of the present invention includes:
(1) Applying the resist composition of the present invention onto a substrate,
(2) drying the applied composition to form a composition layer;
(3) exposing the composition layer to light;
(4) a step of heating the composition layer after exposure; and (5) a step of developing the composition layer after heating.
The resist composition can be applied onto the substrate using a commonly used device such as a spin coater. Examples of the substrate include inorganic substrates such as silicon wafers. Before applying the resist composition, the substrate may be cleaned, or 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 performed, for example, by evaporating the solvent using a heating device such as a hot plate (so-called pre-baking), or by using a pressure reduction device. The heating temperature is preferably 50 to 200°C, and the heating time is preferably 10 to 180 seconds. Further, the pressure during reduced pressure drying is preferably about 1 to 1.0×10 ⁵ Pa.
The obtained composition layer is usually exposed using an exposure machine. The exposure machine may be an immersion exposure machine. Exposure light sources include those that emit laser light in the ultraviolet region such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), solid state laser light source (YAG or semiconductor laser). etc.) that converts the wavelength of laser light and emits harmonic laser light in the far ultraviolet or vacuum ultraviolet range, and uses various methods such as those that emit electron beams and ultraviolet light (EUV). I can do it. Note that in this specification, irradiation with these radiations may be collectively referred to as "exposure." During exposure, the 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 writing 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 in acid-labile groups. The heating temperature is usually about 50 to 200°C, preferably about 70 to 150°C.
The heated composition layer is usually developed using a developer using a developing device. Examples of the developing method include a dip method, a paddle method, a spray method, and a dynamic dispensing method. The development temperature is preferably, for example, 5 to 60°C, and the development time is, for example, preferably 5 to 300 seconds. By selecting the type of developer as described below, a positive resist pattern or a negative resist pattern can be manufactured.
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 the various alkaline aqueous solutions used in this field. Examples 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 organic developers 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; and glycols such as propylene glycol monomethyl ether. Examples include ether solvents; amide solvents such as N,N-dimethylacetamide; and 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 even more preferably substantially only the organic solvent.
Among these, as the organic developer, a developer containing butyl acetate and/or 2-heptanone is preferred. 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. Further, the organic developer may contain a trace amount of water.
During development, development may be stopped by replacing the organic developer with a different type of solvent.
It is preferable to wash the resist pattern after development with a rinsing liquid. The rinsing liquid is not particularly limited as long as it does not dissolve the resist pattern, and solutions containing common organic solvents can be used, preferably alcohol solvents or ester solvents.
After cleaning, it is preferable to remove the rinsing liquid remaining on the substrate and pattern.

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

The present invention will be explained in more detail with reference to Examples. In the examples, "%" and "part" representing the content or amount used are based on mass unless otherwise specified.
The weight average molecular weight is a value determined by gel permeation chromatography. The analysis conditions for gel permeation chromatography are as follows.
Column: TSKgel Multipore HXL-M x 3+guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0mL/min
Detector: RI detector Column temperature: 40℃
Injection volume: 100μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)
The structure of the compound was confirmed by measuring the molecular ion peak using mass spectrometry (LC: Model 1100 manufactured by Agilent; MASS: Model LC/MSD manufactured by Agilent). In the following examples, the value of this molecular ion peak is indicated by "MASS".

式（Ｉ－１－ａ）で表される塩４．８８部及びジメチルホルムアミド２５部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ－１－ｂ）で表される化合物３．８８部を添加し、さらに、５０℃で２時間攪拌した。得られた混合溶液に、式（Ｉ－１－ｃ）で表される化合物３．６２部を添加し、さらに、５０℃で３時間攪拌した後、２３℃まで冷却することにより、式（Ｉ－１－ｄ）で表される塩を含む溶液を得た。

式（Ｉ－１－ｄ）で表される塩を含む溶液に、式（Ｉ－１－ｅ）で表される塩５．８８部及びクロロホルム６０部を添加し、２３℃で２時間攪拌した後、分液して有機層を取り出した。得られた有機層に、イオン交換水６０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を５回繰り返した。得られた有機層をろ過した後、回収されたろ液を濃縮した。得られた濃縮残渣に、ｔｅｒｔ－ブチルメチルエーテル４０部を加えて、２３℃で３０分間攪拌した後、上澄み液を除去し、濃縮することにより、式（Ｉ－１）で表される塩５．３６部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ３４９．１ Example 1: Synthesis of salt represented by formula (I-1)

4.88 parts of the salt represented by formula (I-1-a) and 25 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. To the obtained mixed solution, 3.88 parts of the compound represented by formula (I-1-b) was added, and the mixture was further stirred at 50° C. for 2 hours. To the obtained mixed solution, 3.62 parts of the compound represented by formula (I-1-c) was added, and the mixture was further stirred at 50°C for 3 hours, and then cooled to 23°C. A solution containing the salt represented by -1-d) was obtained.

5.88 parts of the salt represented by formula (I-1-e) and 60 parts of chloroform were added to a solution containing the salt represented by formula (I-1-d), and the mixture was stirred at 23°C for 2 hours. After that, the organic layer was separated. After adding 60 parts of ion-exchanged water to the obtained organic layer and stirring at 23° C. for 30 minutes, the organic layer was separated. This water washing operation was repeated five times. After filtering the obtained organic layer, the collected filtrate was concentrated. After adding 40 parts of tert-butyl methyl ether to the obtained concentrated residue and stirring at 23°C for 30 minutes, the supernatant was removed and concentrated to obtain the salt 5 represented by formula (I-1). .36 copies were obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI(-)Spectrum): M ^- 349.1

式（Ｉ－１－ａ）で表される塩４．８８部及びジメチルホルムアミド２５部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ－１－ｂ）で表される化合物３．８８部を添加し、さらに、５０℃で２時間攪拌した。得られた混合溶液に、式（Ｉ－１－ｃ）で表される化合物３．６２部を添加し、さらに、５０℃で３時間攪拌した後、２３℃まで冷却することにより、式（Ｉ－１－ｄ）で表される塩を含む溶液を得た。

式（Ｉ－１－ｄ）で表される塩を含む溶液に、式（Ｉ－１４１－ｅ）で表される塩６．８５部及びクロロホルム６０部を添加し、２３℃で２時間攪拌した。得られた混合物に、５％シュウ酸水溶液６０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。得られた有機層に、イオン交換水６０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を５回繰り返した。得られた有機層をろ過した後、回収されたろ液を濃縮した。得られた濃縮残渣に、ｔｅｒｔ－ブチルメチルエーテル４０部を加えて、２３℃で３０分間攪拌した後、ろ過することにより、式（Ｉ－１４１）で表される塩４．９９部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２３７．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ３４９．１ Example 2: Synthesis of salt represented by formula (I-141)

4.88 parts of the salt represented by formula (I-1-a) and 25 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. To the obtained mixed solution, 3.88 parts of the compound represented by formula (I-1-b) was added, and the mixture was further stirred at 50° C. for 2 hours. To the obtained mixed solution, 3.62 parts of the compound represented by formula (I-1-c) was added, and the mixture was further stirred at 50°C for 3 hours, and then cooled to 23°C. A solution containing the salt represented by -1-d) was obtained.

6.85 parts of the salt represented by formula (I-141-e) and 60 parts of chloroform were added to a solution containing the salt represented by formula (I-1-d), and the mixture was stirred at 23°C for 2 hours. . After adding 60 parts of a 5% oxalic acid aqueous solution to the obtained mixture and stirring at 23°C for 30 minutes, the mixture was separated and the organic layer was taken out. After adding 60 parts of ion-exchanged water to the obtained organic layer and stirring at 23° C. for 30 minutes, the organic layer was separated. This water washing operation was repeated five times. After filtering the obtained organic layer, the collected filtrate was concentrated. 40 parts of tert-butyl methyl ether was added to the obtained concentrated residue, stirred at 23°C for 30 minutes, and filtered to obtain 4.99 parts of a salt represented by formula (I-141). .
MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI(-)Spectrum): M ^- 349.1

式（Ｉ－１－ａ）で表される塩４．８８部及びジメチルホルムアミド２５部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ－１－ｂ）で表される化合物３．８８部を添加し、さらに、５０℃で２時間攪拌した。得られた混合溶液に、式（Ｉ－２－ｃ）で表される化合物３．６２部を添加し、さらに、５０℃で３時間攪拌した後、２３℃まで冷却することにより、式（Ｉ－２－ｄ）で表される塩を含む溶液を得た。

式（Ｉ－２－ｄ）で表される塩を含む溶液に、式（Ｉ－１－ｅ）で表される塩５．８８部及びクロロホルム６０部を添加し、２３℃で２時間攪拌した後、分液して有機層を取り出した。得られた有機層に、イオン交換水６０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を５回繰り返した。得られた有機層をろ過した後、回収されたろ液を濃縮した。得られた濃縮残渣に、ｔｅｒｔ－ブチルメチルエーテル４０部を加えて、２３℃で３０分間攪拌した後、上澄み液を除去し、濃縮することにより、式（Ｉ－２）で表される塩４．１２部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ３４９．１ Example 3: Synthesis of salt represented by formula (I-2)

4.88 parts of the salt represented by formula (I-1-a) and 25 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. To the obtained mixed solution, 3.88 parts of the compound represented by formula (I-1-b) was added, and the mixture was further stirred at 50° C. for 2 hours. To the obtained mixed solution, 3.62 parts of the compound represented by formula (I-2-c) was added, and the mixture was further stirred at 50°C for 3 hours, and then cooled to 23°C. A solution containing the salt represented by -2-d) was obtained.

5.88 parts of the salt represented by formula (I-1-e) and 60 parts of chloroform were added to a solution containing the salt represented by formula (I-2-d), and the mixture was stirred at 23°C for 2 hours. After that, the organic layer was separated. After adding 60 parts of ion-exchanged water to the obtained organic layer and stirring at 23° C. for 30 minutes, the organic layer was separated. This water washing operation was repeated five times. After filtering the obtained organic layer, the collected filtrate was concentrated. After adding 40 parts of tert-butyl methyl ether to the obtained concentrated residue and stirring at 23°C for 30 minutes, the supernatant was removed and concentrated to obtain the salt 4 represented by formula (I-2). .12 copies were obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI(-)Spectrum): M ^- 349.1

式（Ｉ－１６－ａ）で表される塩５．２７部及びジメチルホルムアミド２５部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ－１－ｂ）で表される化合物３．８８部を添加し、さらに、５０℃で２時間攪拌した。得られた混合溶液に、式（Ｉ－２－ｃ）で表される化合物３．６２部を添加し、さらに、５０℃で３時間攪拌した後、２３℃まで冷却することにより、式（Ｉ－１６－ｄ）で表される塩を含む溶液を得た。

式（Ｉ－１６－ｄ）で表される塩を含む溶液に、式（Ｉ－１－ｅ）で表される塩５．８８部及びクロロホルム６０部を添加し、２３℃で２時間攪拌した後、分液して有機層を取り出した。得られた有機層に、イオン交換水６０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を５回繰り返した。得られた有機層をろ過した後、回収されたろ液を濃縮した。得られた濃縮残渣に、ｔｅｒｔ－ブチルメチルエーテル４０部を加えて、２３℃で３０分間攪拌した後、上澄み液を除去し、濃縮することにより、式（Ｉ－１６）で表される塩３．９８部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ３６７．１ Example 4: Synthesis of salt represented by formula (I-16)

5.27 parts of the salt represented by formula (I-16-a) and 25 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. To the obtained mixed solution, 3.88 parts of the compound represented by formula (I-1-b) was added, and the mixture was further stirred at 50° C. for 2 hours. To the obtained mixed solution, 3.62 parts of the compound represented by formula (I-2-c) was added, and the mixture was further stirred at 50°C for 3 hours, and then cooled to 23°C. A solution containing the salt represented by -16-d) was obtained.

5.88 parts of the salt represented by formula (I-1-e) and 60 parts of chloroform were added to a solution containing the salt represented by formula (I-16-d), and the mixture was stirred at 23°C for 2 hours. After that, the organic layer was separated. After adding 60 parts of ion-exchanged water to the obtained organic layer and stirring at 23° C. for 30 minutes, the organic layer was separated. This water washing operation was repeated five times. After filtering the obtained organic layer, the collected filtrate was concentrated. After adding 40 parts of tert-butyl methyl ether to the obtained concentrated residue and stirring at 23°C for 30 minutes, the supernatant was removed and concentrated to obtain the salt 3 represented by formula (I-16). .98 copies were obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI(-)Spectrum): M ^- 367.1

式（Ｉ－１－ａ）で表される塩４．８８部及びジメチルホルムアミド２５部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ－１－ｂ）で表される化合物３．８８部を添加し、さらに、５０℃で２時間攪拌した。得られた混合溶液に、式（Ｉ－３－ｃ）で表される化合物３．９３部を添加し、さらに、５０℃で３時間攪拌した後、２３℃まで冷却することにより、式（Ｉ－３－ｄ）で表される塩を含む溶液を得た。

式（Ｉ－３－ｄ）で表される塩を含む溶液に、式（Ｉ－１－ｅ）で表される塩５．８８部及びクロロホルム６０部を添加し、２３℃で２時間攪拌した後、分液して有機層を取り出した。得られた有機層に、イオン交換水６０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を５回繰り返した。得られた有機層をろ過した後、回収されたろ液を濃縮した。得られた濃縮残渣に、ｔｅｒｔ－ブチルメチルエーテル４０部を加えて、２３℃で３０分間攪拌した後、上澄み液を除去し、濃縮することにより、式（Ｉ－３）で表される塩３．９８部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ３６３．１ Example 5: Synthesis of salt represented by formula (I-3)

4.88 parts of the salt represented by formula (I-1-a) and 25 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. To the obtained mixed solution, 3.88 parts of the compound represented by formula (I-1-b) was added, and the mixture was further stirred at 50° C. for 2 hours. To the obtained mixed solution, 3.93 parts of the compound represented by formula (I-3-c) was added, and the mixture was further stirred at 50°C for 3 hours, and then cooled to 23°C. A solution containing the salt represented by -3-d) was obtained.

5.88 parts of the salt represented by formula (I-1-e) and 60 parts of chloroform were added to a solution containing the salt represented by formula (I-3-d), and the mixture was stirred at 23°C for 2 hours. After that, the organic layer was separated. After adding 60 parts of ion-exchanged water to the obtained organic layer and stirring at 23° C. for 30 minutes, the organic layer was separated. This water washing operation was repeated five times. After filtering the obtained organic layer, the collected filtrate was concentrated. After adding 40 parts of tert-butyl methyl ether to the obtained concentrated residue and stirring at 23°C for 30 minutes, the supernatant was removed and concentrated to obtain the salt 3 represented by formula (I-3). .98 copies were obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI(-)Spectrum): M ^- 363.1

式（Ｉ－１６－ａ）で表される塩５．２７部及びジメチルホルムアミド２５部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ－１－ｂ）で表される化合物３．８８部を添加し、さらに、５０℃で２時間攪拌した。得られた混合溶液に、式（Ｉ－３－ｃ）で表される化合物３．９３部を添加し、さらに、５０℃で３時間攪拌した後、２３℃まで冷却することにより、式（Ｉ－２０１－ｄ）で表される塩を含む溶液を得た。

式（Ｉ－２０１－ｄ）で表される塩を含む溶液に、式（Ｉ－１－ｅ）で表される塩５．８８部及びクロロホルム６０部を添加し、２３℃で２時間攪拌した後、分液して有機層を取り出した。得られた有機層に、イオン交換水６０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を５回繰り返した。得られた有機層をろ過した後、回収されたろ液を濃縮した。得られた濃縮残渣に、ｔｅｒｔ－ブチルメチルエーテル４０部を加えて、２３℃で３０分間攪拌した後、上澄み液を除去し、濃縮することにより、式（Ｉ－２０１）で表される塩３．１１部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ３８１．１ Example 6: Synthesis of salt represented by formula (I-201)

5.27 parts of the salt represented by formula (I-16-a) and 25 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. To the obtained mixed solution, 3.88 parts of the compound represented by formula (I-1-b) was added, and the mixture was further stirred at 50° C. for 2 hours. To the obtained mixed solution, 3.93 parts of the compound represented by formula (I-3-c) was added, and the mixture was further stirred at 50°C for 3 hours, and then cooled to 23°C. A solution containing the salt represented by -201-d) was obtained.

5.88 parts of the salt represented by formula (I-1-e) and 60 parts of chloroform were added to a solution containing the salt represented by formula (I-201-d), and the mixture was stirred at 23°C for 2 hours. After that, the organic layer was separated. After adding 60 parts of ion-exchanged water to the obtained organic layer and stirring at 23° C. for 30 minutes, the organic layer was separated. This water washing operation was repeated five times. After filtering the obtained organic layer, the collected filtrate was concentrated. After adding 40 parts of tert-butyl methyl ether to the obtained concentrated residue and stirring at 23°C for 30 minutes, the supernatant was removed and concentrated to obtain the salt 3 represented by formula (I-201). .11 copies were obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI(-)Spectrum): M ^- 381.1

式（Ｉ－１６－ａ）で表される塩５．２７部及びジメチルホルムアミド２５部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ－１－ｂ）で表される化合物３．８８部を添加し、さらに、５０℃で２時間攪拌した。得られた混合溶液に、式（Ｉ－２３１－ｃ）で表される化合物２．４９部を添加し、さらに、５０℃で３時間攪拌した後、２３℃まで冷却することにより、式（Ｉ－２３１－ｄ）で表される塩を含む溶液を得た。

式（Ｉ－２３１－ｄ）で表される塩を含む溶液に、式（Ｉ－１－ｅ）で表される塩５．８８部及びクロロホルム６０部を添加し、２３℃で２時間攪拌した後、分液して有機層を取り出した。得られた有機層に、イオン交換水６０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を５回繰り返した。得られた有機層をろ過した後、回収されたろ液を濃縮した。得られた濃縮残渣に、ｔｅｒｔ－ブチルメチルエーテル４０部を加えて、２３℃で３０分間攪拌した後、上澄み液を除去し、濃縮することにより、式（Ｉ－２３１）で表される塩７．８９部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ３１５．１ Example 7: Synthesis of salt represented by formula (I-231)

5.27 parts of the salt represented by formula (I-16-a) and 25 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. To the obtained mixed solution, 3.88 parts of the compound represented by formula (I-1-b) was added, and the mixture was further stirred at 50° C. for 2 hours. To the obtained mixed solution, 2.49 parts of the compound represented by formula (I-231-c) was added, and the mixture was further stirred at 50°C for 3 hours, and then cooled to 23°C. A solution containing the salt represented by -231-d) was obtained.

5.88 parts of the salt represented by formula (I-1-e) and 60 parts of chloroform were added to a solution containing the salt represented by formula (I-231-d), and the mixture was stirred at 23°C for 2 hours. After that, the organic layer was separated. After adding 60 parts of ion-exchanged water to the obtained organic layer and stirring at 23° C. for 30 minutes, the organic layer was separated. This water washing operation was repeated five times. After filtering the obtained organic layer, the collected filtrate was concentrated. After adding 40 parts of tert-butyl methyl ether to the obtained concentrated residue and stirring at 23°C for 30 minutes, the supernatant was removed and concentrated to obtain the salt 7 represented by formula (I-231). .89 copies were obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI(-)Spectrum): M ^- 315.1

式（Ｉ－１６－ａ）で表される塩５．２７部及びジメチルホルムアミド２５部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ－１－ｂ）で表される化合物３．８８部を添加し、さらに、５０℃で２時間攪拌した。得られた混合溶液に、式（Ｉ－２３２－ｃ）で表される化合物２．８０部を添加し、さらに、５０℃で３時間攪拌した後、２３℃まで冷却することにより、式（Ｉ－２３２－ｄ）で表される塩を含む溶液を得た。

式（Ｉ－２３２－ｄ）で表される塩を含む溶液に、式（Ｉ－１－ｅ）で表される塩５．８８部及びクロロホルム６０部を添加し、２３℃で２時間攪拌した後、分液して有機層を取り出した。得られた有機層に、イオン交換水６０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を５回繰り返した。得られた有機層をろ過した後、回収されたろ液を濃縮した。得られた濃縮残渣に、ｔｅｒｔ－ブチルメチルエーテル４０部を加えて、２３℃で３０分間攪拌した後、上澄み液を除去し、濃縮することにより、式（Ｉ－２３２）で表される塩７．１６部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ３２９．１ Example 8: Synthesis of salt represented by formula (I-232)

5.27 parts of the salt represented by formula (I-16-a) and 25 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. To the obtained mixed solution, 3.88 parts of the compound represented by formula (I-1-b) was added, and the mixture was further stirred at 50° C. for 2 hours. To the obtained mixed solution, 2.80 parts of the compound represented by formula (I-232-c) was added, and the mixture was further stirred at 50°C for 3 hours, and then cooled to 23°C. A solution containing a salt represented by -232-d) was obtained.

5.88 parts of the salt represented by formula (I-1-e) and 60 parts of chloroform were added to a solution containing the salt represented by formula (I-232-d), and the mixture was stirred at 23°C for 2 hours. After that, the organic layer was separated. After adding 60 parts of ion-exchanged water to the obtained organic layer and stirring at 23° C. for 30 minutes, the organic layer was separated. This water washing operation was repeated five times. After filtering the obtained organic layer, the collected filtrate was concentrated. After adding 40 parts of tert-butyl methyl ether to the obtained concentrated residue and stirring at 23°C for 30 minutes, the supernatant was removed and concentrated to obtain the salt 7 represented by formula (I-232). .16 copies were obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI(-)Spectrum): M ^- 329.1

式（Ｉ－１６－ａ）で表される塩５．２７部及びジメチルホルムアミド２５部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ－１－ｂ）で表される化合物３．８８部を添加し、さらに、５０℃で２時間攪拌した。得られた混合溶液に、式（Ｉ－２３１－ｃ）で表される化合物２．４９部を添加し、さらに、５０℃で３時間攪拌した後、２３℃まで冷却することにより、式（Ｉ－２３１－ｄ）で表される塩を含む溶液を得た。

式（Ｉ－２３１－ｄ）で表される塩を含む溶液に、式（Ｉ－２４６－ｅ）で表される塩６．２３部及びクロロホルム６０部を添加し、２３℃で２時間攪拌した後、分液して有機層を取り出した。得られた有機層に、イオン交換水６０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を５回繰り返した。得られた有機層をろ過した後、回収されたろ液を濃縮した。得られた濃縮残渣に、ｔｅｒｔ－ブチルメチルエーテル４０部を加えて、２３℃で３０分間攪拌した後、上澄み液を除去し、濃縮することにより、式（Ｉ－２４６）で表される塩７．９９部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２８１．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ３１５．１ Example 9: Synthesis of salt represented by formula (I-246)

5.27 parts of the salt represented by formula (I-16-a) and 25 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. To the obtained mixed solution, 3.88 parts of the compound represented by formula (I-1-b) was added, and the mixture was further stirred at 50° C. for 2 hours. To the obtained mixed solution, 2.49 parts of the compound represented by formula (I-231-c) was added, and the mixture was further stirred at 50°C for 3 hours, and then cooled to 23°C. A solution containing the salt represented by -231-d) was obtained.

6.23 parts of the salt represented by formula (I-246-e) and 60 parts of chloroform were added to a solution containing the salt represented by formula (I-231-d), and the mixture was stirred at 23°C for 2 hours. After that, the organic layer was separated. After adding 60 parts of ion-exchanged water to the obtained organic layer and stirring at 23° C. for 30 minutes, the organic layer was separated. This water washing operation was repeated five times. After filtering the obtained organic layer, the collected filtrate was concentrated. After adding 40 parts of tert-butyl methyl ether to the obtained concentrated residue and stirring at 23°C for 30 minutes, the supernatant was removed and concentrated to obtain the salt 7 represented by formula (I-246). .99 copies were obtained.
MASS (ESI (+) Spectrum): M ⁺ 281.1
MASS (ESI(-)Spectrum): M ^- 315.1

式（Ｉ－１６－ａ）で表される塩５．２７部及びジメチルホルムアミド２５部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ－１－ｂ）で表される化合物３．８８部を添加し、さらに、５０℃で２時間攪拌した。得られた混合溶液に、式（Ｉ－２３１－ｃ）で表される化合物２．４９部を添加し、さらに、５０℃で３時間攪拌した後、２３℃まで冷却することにより、式（Ｉ－２３１－ｄ）で表される塩を含む溶液を得た。

式（Ｉ－２３１－ｄ）で表される塩を含む溶液に、式（Ｉ－２４９－ｅ）で表される塩６．９４部及びクロロホルム６０部を添加し、２３℃で２時間攪拌した後、分液して有機層を取り出した。得られた有機層に、イオン交換水６０部を加えて２３℃で３０分間攪拌した後、分液して有機層を取り出した。この水洗操作を５回繰り返した。得られた有機層をろ過した後、回収されたろ液を濃縮した。得られた濃縮残渣に、ｔｅｒｔ－ブチルメチルエーテル４０部を加えて、２３℃で３０分間攪拌した後、上澄み液を除去し、濃縮することにより、式（Ｉ－２４９）で表される塩６．１２部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ３１７．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ３１５．１ Example 10: Synthesis of salt represented by formula (I-249)

5.27 parts of the salt represented by formula (I-16-a) and 25 parts of dimethylformamide were mixed and stirred at 23°C for 30 minutes. To the obtained mixed solution, 3.88 parts of the compound represented by formula (I-1-b) was added, and the mixture was further stirred at 50° C. for 2 hours. To the obtained mixed solution, 2.49 parts of the compound represented by formula (I-231-c) was added, and the mixture was further stirred at 50°C for 3 hours, and then cooled to 23°C. A solution containing the salt represented by -231-d) was obtained.

6.94 parts of the salt represented by formula (I-249-e) and 60 parts of chloroform were added to a solution containing the salt represented by formula (I-231-d), and the mixture was stirred at 23°C for 2 hours. After that, the organic layer was separated. After adding 60 parts of ion-exchanged water to the obtained organic layer and stirring at 23° C. for 30 minutes, the organic layer was separated. This water washing operation was repeated five times. After filtering the obtained organic layer, the collected filtrate was concentrated. After adding 40 parts of tert-butyl methyl ether to the obtained concentrated residue and stirring at 23°C for 30 minutes, the supernatant was removed and concentrated to obtain the salt 6 represented by formula (I-249). .12 copies were obtained.
MASS (ESI (+) Spectrum): M ⁺ 317.1
MASS (ESI(-)Spectrum): M ^- 315.1

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

Synthesis example 1 [Synthesis of resin A1]
As monomers, monomer (a1-4-2), monomer (a1-1-3) and monomer (a1-2-6) were used, and their molar ratio [monomer (a1-4-2): monomer (a1-1 -3):monomer (a1-2-6)] were mixed in a ratio of 38:24:38, and then added to this monomer mixture by 1.5 times the total mass of all monomers. of methyl isobutyl ketone were mixed. To the obtained mixture, azobisisotyronitrile was added as an initiator in an amount of 7 mol% based on the total number of moles of all monomers, and polymerization was performed by heating this at 85° C. for about 5 hours. . Thereafter, an aqueous p-toluenesulfonic acid solution was added to the polymerization reaction solution, stirred for 6 hours, and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate the resin, and by filtering and collecting it, a resin A1 (copolymer) with a weight average molecular weight of about 5.3 x 10 ³ was obtained in a yield of 78%. Obtained in %. This resin A1 has the following structural units.

<Preparation of resist composition>
As shown in Table 2, a resist composition was prepared by mixing the following components and filtering the resulting mixture through a fluororesin filter with a pore size of 0.2 μm.

ＩＸ－２：式（ＩＸ－２）で表される塩（特開２００５－０９７２５４号公報の実施例に従って合成）

ＩＸ－３：式（ＩＸ－３）で表される塩（特開２００５－０９７２５４号公報の実施例に従って合成）

ＩＸ－４：式（ＩＸ－４）で表される塩（特開平０９－２４４２３４号公報の実施例を参考に合成）

＜クエンチャー（Ｃ）＞
Ｃ１：特開２０１１－３９５０２号公報記載の方法で合成

＜溶剤（Ｅ）＞
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 １００部
γ－ブチロラクトン ５部 <Resin>
A1: Resin A1
<Salt (I)>
I-1: Salt represented by formula (I-1) I-2: Salt represented by formula (I-2) I-3: Salt represented by formula (I-3) I-16: Formula Salt represented by (I-16) I-141: Salt represented by formula (I-141) I-201: Salt represented by formula (I-201) I-231: Formula (I-231) I-232: Salt represented by formula (I-232) I-246: Salt represented by formula (I-246) I-249: Salt represented by formula (I-249) <Acid generator>
IX-1: Salt represented by formula (IX-1) (synthesized according to the examples of JP-A No. 2004-203858)

IX-2: Salt represented by formula (IX-2) (synthesized according to the examples of JP-A No. 2005-097254)

IX-3: Salt represented by formula (IX-3) (synthesized according to the examples of JP-A-2005-097254)

IX-4: Salt represented by formula (IX-4) (synthesized with reference to the examples of JP-A-09-244234)

<Quencher (C)>
C1: Synthesized by the method described in JP-A-2011-39502

<Solvent (E)>
Propylene glycol monomethyl ether acetate 400 parts Propylene glycol monomethyl ether 100 parts γ-butyrolactone 5 parts

(Electron beam exposure evaluation of resist composition)
A 6-inch silicon wafer was treated with hexamethyldisilazane at 90° C. for 60 seconds on a direct hot plate. A resist composition was spin-coated onto this silicon wafer so that the thickness of the composition layer was 0.04 μm. Thereafter, it was prebaked for 60 seconds on a direct hot plate at the temperature shown in the "PB" column of Table 2 to form a composition layer. A line-and-space pattern (pitch 60 nm/line) was formed on the composition layer formed on the wafer using an electron beam drawing machine [ELS-F125 125 keV manufactured by Elionix Co., Ltd.] by changing the exposure amount stepwise. A width of 30 nm) was directly drawn.
After exposure, post-exposure baking was performed for 60 seconds on a hot plate at the temperature shown in the "PEB" column of Table 2, and further paddle development was performed for 60 seconds with a 2.38% by mass tetramethylammonium hydroxide aqueous solution. , a resist pattern was obtained.
The obtained resist pattern (line and space pattern) was observed with a scanning electron microscope, and the exposure amount at which the line width and space width of the line and space pattern with a pitch of 60 nm was 1:1 was defined as the effective sensitivity.

Line edge roughness evaluation (LER): The amplitude of unevenness on the side wall surface of a resist pattern manufactured at effective sensitivity was measured using a scanning electron microscope, and line edge roughness was determined. The results are shown in Table 3.

Compared to Comparative Compositions 1 to 4, compositions 1 to 10 had smaller variations in unevenness on the side wall surfaces of the resist patterns, and the line edge roughness evaluation was good.

The salt of the present invention and the resist composition containing the salt have good line edge roughness and are useful for microfabrication of semiconductors.

Claims (7)

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

[In formula (I),
R ¹ is an alicyclic hydrocarbon group having a substituent and having 3 to 18 carbon atoms (-CH ₂ - contained in the alicyclic hydrocarbon group is -O-, -S-, -SO ₂ - or may be replaced with -CO-),
Aromatic hydrocarbon group having 6 to 18 carbon atoms having a substituent,
A group that combines a substituent- containing alicyclic hydrocarbon group having 3 to 18 carbon atoms and a chain hydrocarbon group having 1 to 6 carbon atoms (-CH ₂ - contained in the alicyclic hydrocarbon group is , -O-, -S-, -SO ₂ - or -CO- may be substituted, and -CH ₂ - contained in the chain hydrocarbon group is replaced with -O- or -CO-. ), or
A group that combines a substituent- containing aromatic hydrocarbon group having 6 to 18 carbon atoms and a chain hydrocarbon group having 1 to 6 carbon atoms (-CH ₂ - contained in the chain hydrocarbon group is - may be replaced with O- or -CO-) ,
The substituent is an alkyl group having 1 to 12 carbon atoms (-CH ₂ - contained in the alkyl group may be replaced with -O- or -CO-) or a halogen atom .
R ² represents a fluorine atom, a bromine atom, an iodine atom, or an alkyl group having 1 to 6 carbon atoms.
m2 represents any integer from 0 to 4, and when m2 is 2 or more, a plurality of R ² may be the same or different.
Z ⁺ represents a cation represented by formula (b2-1), formula (b2-2), formula (b2-3) or formula (b2-4). ]

[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. The hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with 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. The hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group, or an alkoxy group having 1 to 12 carbon atoms.
R ^b4 and R ^b5 may bond to each other and 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 any integer from 0 to 5.
When m2 is 2 or more, multiple R ^b7s may be the same or different; when n2 is 2 or more, multiple R ^b8s 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 bond to each other and 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; The hydrogen atom contained in the aromatic hydrocarbon group may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group may be substituted with an alkoxy group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 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 is -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 any integer from 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 ^b13s are the same or different; when p2 is 2 or more, multiple R ^b14s are the same or different; when q2 is 2 or more, multiple R ^b15s are the same or different. , when r2 is 2 or more, multiple R ^b16s are the same or different; when s2 is 2 or more, multiple R ^b17s are the same or different; when t2 is 2 or more, multiple R ^b18s are the same or different; different. ] R ¹ is a monocyclic alicyclic hydrocarbon group having a substituent and having 3 to 8 carbon atoms (-CH ₂ - contained in the alicyclic hydrocarbon group is -O-, -S-, - SO ₂ - or -CO- may be substituted), a polycyclic alicyclic hydrocarbon group having 6 to 12 carbon atoms having a substituent (-CH ₂ contained in the alicyclic hydrocarbon group) - may be replaced with -O-, -S-, -SO ₂ - or -CO-), a monocyclic alicyclic hydrocarbon group having 3 to 8 carbon atoms having a substituent and carbon A group combining a chain hydrocarbon group of numbers 1 to 6 (-CH ₂ - contained in the alicyclic hydrocarbon group is replaced with -O-, -S-, -SO ₂ - or -CO-) -CH ₂ - contained in the chain hydrocarbon group may be replaced with -O- or -CO-), or a polycarbonate group having 6 to 12 carbon atoms with a substituent. A group that combines a ring alicyclic hydrocarbon group and a chain hydrocarbon group having 1 to 6 carbon atoms (-CH ₂ - contained in the alicyclic hydrocarbon group is -O-, -S-, -SO ₂ - or -CO- may be substituted, and -CH ₂ - contained in the chain hydrocarbon group may be replaced with -O- or -CO-. The acid generator described in . A resist composition comprising the acid generator according to claim 1 or 2 and a resin having an acid-labile group. 4. The resist composition according to claim 3, wherein the resin having an acid-labile group contains at least one of a structural unit represented by formula (a1-1) and a structural unit represented by formula (a1-2).

[In formula (a1-1) and formula (a1-2),
L ^a1 and L ^a2 each independently represent -O- or *-O-(CH ₂ ) _k1 -CO-O-, k1 represents an integer from 1 to 7, and * represents a bond with -CO- represents a hand.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
m1 represents any integer from 0 to 14.
n1 represents any integer from 0 to 10.
n1' represents any integer from 0 to 3. ] 5. The resist composition according to claim 3, wherein the resin having an acid-labile group further contains a structural unit represented by formula (a2-A).

[In 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, hydroxy group, alkyl group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms, alkylcarbonyl group having 2 to 4 carbon atoms, alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl 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 is bonded.
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 any integer from 0 to 4. When mb is any integer of 2 or more, a plurality of R ^a51 's may be the same or different. ] 6. The resist composition according to claim 3, further comprising a salt that generates an acid having weaker acidity than the acid generated from the acid generator. (1) applying the resist composition according to any one of claims 3 to 6 onto a substrate;
(2) drying the applied composition to form a composition layer;
(3) exposing the composition layer to light;
(4) a step of heating the composition layer after exposure; and (5) a step of developing the composition layer after heating.
A method for manufacturing a resist pattern including: