JP2021017442A - Salt, quencher, resist composition, and method for producing resist pattern - Google Patents

Abstract

To provide a salt capable of producing a resist pattern having good CD uniformity (CDU) and a resist composition containing the salt.SOLUTION: A salt represented by formula (I), a quencher, and a resist composition containing the same are provided. [In the formula, R1 represents a halogen atom, a hydrocarbon group or the like; R2 and R3 each represent a halogen atom, a hydrocarbon group or the like or R2 and R3 may combine to form a single bond or an alkanediyl bridge together with carbon atoms to which they are bonded; -CH2- contained in the alkanediyl bridge may be substituted with -O-, -S- -CO- or the like; m1 represents an integer of 0 to 4; m2 and m3 each represent an integer of 0 to 5; and L1 represents an alkanediyl group.]SELECTED DRAWING: None

Description

The present invention relates to a salt, a quencher and a resist composition containing the salt, and a method for producing a resist pattern using the resist composition.

Patent Document 1 describes a resist composition containing a salt having the following structural formula, a resin containing a structural unit having an acid unstable group, and an acid generator.
Patent Document 2 describes a resist composition containing a salt having the following structural formula, a resin containing a structural unit having an acid unstable group, and an acid generator.

JP-A-2017-202993 JP-A-2018-066985

An object of the present invention is to provide a salt that forms a resist pattern having better CD uniformity (CDU) than a resist pattern formed from the resist composition containing the above salt.

The present invention includes the following inventions.
[1] A salt represented by the formula (I).
[In formula (I),
R ¹ represents a halogen atom, an alkyl fluoride group having 1 to 6 carbon atoms, or a hydrocarbon group having 1 to 18 carbon atoms, and −CH ₂ − contained in the hydrocarbon group is −O− or −CO−. It may be replaced with.
R ² and R ³ independently represent a halogen atom, an alkyl fluoride group having 1 to 6 carbon atoms, or a hydrocarbon group having 1 to 18 carbon atoms, and −CH ₂ − contained in the hydrocarbon group is It may be replaced by —O— or −CO−, or R ² and R ³ together to form a single bond or an alkanedyl bridge with 1 to 6 carbon atoms with the carbon atoms to which they are bonded. at best, _-CH 2 contained in the alkanediyl bridge - is, -O -, - S -, - CO -, - SO- or -SO ₂ - may be replaced with.
m1 represents an integer of 0 to 4, when m1 is 2 or more, plural R ¹ may be the same or different from each other.
m2 represents any integer from 0 to 5, and when m2 is 2 or more, a plurality of R ^2s may be the same or different from each other.
m3 represents an integer of 0 to 5, when m3 is 2 or more, plural R ³ may be the same or different from each other.
L ¹ represents an alkanediyl group having 1 to 6 carbon atoms. ]
[2] A quencher containing the salt according to [1].
[3] A resist composition containing the citric acid according to [2], a resin containing a structural unit having an acid unstable group, and an acid generator.
[4] At least one resin selected from the group consisting of a structural unit represented by the formula (a1-1) and a structural unit represented by the formula (a1-2) for a resin containing a structural unit having an acid unstable group. The resist composition according to [3].
[In the formula (a1-1) and the formula (a1-2),
L ^a1 and L ^a2 independently represent -O- or * -O- (CH ₂ ) _k1 -CO-O-, k1 represents an integer of 1 to 7, and * represents -CO-. Represents the binding site with.
R ^a4 and R ^a5 independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group combining these groups.
m1 represents any integer from 0 to 14.
n1 represents any integer from 0 to 10.
n1'represents an integer of 0 to 3. ]
[5] The resist composition according to [4], wherein the resin containing a structural unit having an acid unstable group contains a structural unit represented by the formula (a2-A).
[In formula (a2-A),
R ^a50 represents an alkyl group having 1 to 6 carbon atoms which may have a hydrogen atom, a halogen atom or a halogen atom.
^Ra51 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, and 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 binding site with a 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 independently represent -O-, ^-CO -O- or -O-CO-, respectively.
nb represents 0 or 1.
mb represents any integer from 0 to 4. When mb is any integer of 2 or more, the plurality of Ra ^51s may be the same as or different from each other. ]
[6] The resist composition according to any one of [3] to [5], wherein the acid generator contains a salt represented by the formula (B1).
[In equation (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 an alicyclic hydrocarbon group having 3 to 24 carbon atoms which may have a methyl group which may have a substituent or a substituent, and is contained in the alicyclic hydrocarbon group. CH ₂ - is, -O -, - S -, - SO 2 - or -CO- may be replaced with.
Z ⁺ represents an organic cation. ]
[7] The resist composition according to any one of [3] to [6], which further contains a salt that generates an acid having a weaker acidity than the acid generated from the acid generator.
[8] (1) A step of applying the resist composition according to any one of [3] to [7] onto a substrate.
(2) A step of drying the applied composition to form a composition layer,
(3) Step of exposing the composition layer,
A method for producing a resist pattern, which comprises (4) a step of heating the composition layer after exposure and (5) a step of developing the composition layer after heating.

By using the resist composition containing the salt of the present invention, a resist pattern can be produced with good CD uniformity (CDU).

As used herein, the term "(meth) acrylate" means "at least one of acrylate and methacrylate," respectively. Notations such as "(meth) acrylic acid" and "(meth) acryloyl" have the same meaning.
Further, unless otherwise specified, a group capable of taking a linear, branched and / or ring such as an "aliphatic hydrocarbon group" includes any of them. The “combined group” means a group obtained by binding two or more of the exemplified groups, and the valence of these groups may be appropriately changed depending on the bonding form. By "derived" or "derived", it means that the polymerizable C = C bond contained in the molecule becomes a -CC- group by polymerization. If a stereoisomer is present, it includes all stereoisomers.
In the present specification, the "solid content of the resist composition" means the total amount of the components excluding the solvent (E) described later from the total amount of the resist composition.

[Salt represented by formula (I)]
The salt of the present invention relates to a salt represented by the formula (I) (hereinafter, may be referred to as "salt (I)").
Examples of the halogen atom represented by R ¹ , R ² and R ³ in the formula (I) include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkyl fluoride group having 1 to 6 carbon atoms represented by R ¹ , R ² and R ³ include a trifluoromethyl group, a difluoromethyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group and 1 , 1,2,2-tetrafluoroethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, perfluorobutyl group, 1,1,2,2,3,3,4,4 -Alkyl fluoride groups such as octafluorobutyl group, perfluoropentyl group, 2,2,3,3,4,5,5,5-nonafluoropentyl group and perfluorohexyl group can be mentioned. The alkyl fluoride group preferably has 1 to 4 carbon atoms, and more preferably 1 to 3 carbon atoms.
The hydrocarbon groups having 1 to 18 carbon atoms represented by R ¹ , R ² and R ³ include chain hydrocarbon groups such as alkyl groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups and combinations thereof. Examples include hydrocarbons.
Examples of the alkyl group include an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group and a nonyl group. The number of carbon atoms of the alkyl group is preferably 1 to 12, more preferably 1 to 9, still more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 1. It is 3.

The alicyclic hydrocarbon group may be monocyclic, polycyclic or spiro ring, and may be saturated or unsaturated. Examples of the alicyclic hydrocarbon group include monocyclic cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group, cyclononyl group, cyclodecyl group and cyclododecyl group, norbornyl group and adamantyl group. Examples include polycyclic cycloalkyl groups such as groups. The alicyclic hydrocarbon group preferably has 3 to 16 carbon atoms, more preferably 3 to 12 carbon atoms, and further preferably 3 to 10 carbon atoms.
Specifically, examples of the alicyclic hydrocarbon group include the groups represented below. The binding site can be at any position.
Examples of the aromatic hydrocarbon group include an aryl group such as a phenyl group, a naphthyl group, a biphenyl group, an anthryl group and a phenanthryl group. The number of carbon atoms of the aromatic hydrocarbon group is preferably 6 to 14, and more preferably 6 to 10.
Examples of the combined group include a group combining the above-mentioned alkyl group and alicyclic hydrocarbon group (cycloalkylalkyl group, etc.), an aralkyl group (benzyl group, etc.), and an aromatic hydrocarbon group having an alkyl group (p-. Methylphenyl group, p-tert-butylphenyl group, trill group, xsilyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.), alicyclic hydrocarbon group Examples thereof include an aromatic hydrocarbon group having (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.), an aryl-cycloalkyl group (phenylcyclohexyl group, etc.) and the like.
When -CH ₂ − contained in the hydrocarbon groups represented by R ¹ , R ² and R ³ is replaced with -O- or -CO-, the number of carbon atoms before the replacement is the total carbon of the hydrocarbon group. Let it be a number.
As the replaced group, a hydroxy group (-CH ₂ − contained in the methyl group is replaced with −O −) and a carboxy group (−CH ₂ −CH ₂ − contained in the ethyl group are −O. -CO-replaced group), alkoxy group (-CH ₂ − at any position contained in the alkyl group is replaced with -O-), alkoxycarbonyl group (arbitrary position contained in the alkyl group) -CH ₂ -CH ₂ -replaced with -O-CO-), alkylcarbonyl group (group in which -CH _2-at any position contained in the alkyl group is replaced with -CO-), Examples thereof include an alkylcarbonyloxy group (a group in which −CH ₂ −CH _{2− at} an arbitrary position contained in an alkyl group is replaced with −CO−O−).
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, an undecyloxy group and a dodecyloxy group. Can be mentioned. The number of carbon atoms of the alkoxy group is preferably 1 to 12, more preferably 1 to 9, still more preferably 1 to 6, even more preferably 1 to 4, and even more preferably 1 to 3. Is.
Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, a butoxycarbonyl group and the like. The alkoxycarbonyl group has preferably 2 to 13 carbon atoms, more preferably 2 to 10 carbon atoms, still more preferably 2 to 7 carbon atoms, and even more preferably 2 to 5 carbon atoms.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, a butyryl group and the like. The alkylcarbonyl group preferably has 2 to 13 carbon atoms, more preferably 2 to 10 carbon atoms, still more preferably 2 to 7 carbon atoms, and even more preferably 2 to 5 carbon atoms.
Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, a propylcarbonyloxy group, a butylcarbonyloxy group and the like. The alkylcarbonyloxy group preferably has 2 to 13 carbon atoms, more preferably 2 to 10 carbon atoms, still more preferably 2 to 7 carbon atoms, and even more preferably 2 to 5 carbon atoms.

Examples of the group in which −CH ₂ − contained in the alicyclic hydrocarbon group is replaced with −O− or −CO− include the following groups. The binding site can be at any position.
m1 is preferably an integer of 0 to 3.
It is preferable that m2 and m3 are independently integers of 0 to 2. m2 and m3 are each independently 1 or greater, taken together R ² and R ^3, together with the carbon atoms to which they are attached, a single bond or a 1 to 6 carbon atoms alkanediyl bridge (the alkanediyl bridge is, -O - - _-CH 2 contained, - S -, - CO - , - SO- or -SO ₂ -. which may be substituted with) it is more preferable to form the.
R ¹ is a fluorine atom, an alkyl fluoride group having 1 to 4 carbon atoms, an alkyl group having 1 to 6 carbon atoms, or an alicyclic hydrocarbon group having 3 to 10 carbon atoms (the alkyl group and the alicyclic hydrocarbon). The −CH ₂₋ contained in the group may be replaced with −O− or −CO−).
A fluorine atom, an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 3 to 10 carbon atoms (-CH ₂ − contained in the alkyl group and the alicyclic hydrocarbon group is -O- or-. It may be replaced by CO-), more preferably.
It is more preferably a fluorine atom or an alkyl group having 1 to 4 carbon atoms (-CH ₂ − contained in the alkyl group may be replaced with −O− or −CO−).
It is even more preferable that the alkyl group has 1 to 3 carbon atoms (-CH ₂ − contained in the alkyl group may be replaced with −O− or −CO−).
R ² and R ³ are independently a fluorine atom, an alkyl fluoride group having 1 to 4 carbon atoms, an alkyl group having 1 to 6 carbon atoms, or an alicyclic hydrocarbon group having 3 to 10 carbon atoms (the alkyl group). And -CH _2- contained in the alicyclic hydrocarbon group may be replaced by -O- or -CO-), or R ² and R ³ are combined and they are bonded. together with the carbon atom, a single bond or a C 1-6 alkanediyl bridge _(-CH 2 contained in the alkanediyl bridge - is, -O -, - S -, - CO -, - SO- or -SO ₂ - It may be replaced with), and it is preferable to form
A fluorine atom, an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 3 to 10 carbon atoms (-CH ₂ − contained in the alkyl group and the alicyclic hydrocarbon group is -O- or-. It may be replaced by CO-), or R ² and R ³ may be combined together with the carbon atoms to which they are bonded, as well as a single bond or a hydrocarbon bridge with 1 to 6 carbon atoms (to the alkylandyl bridge). is, -O - - _-CH 2 contained, - S -, - CO - , - SO- or -SO ₂ -. which may be substituted with) it is more preferable to form the,
Fluorine atom or an alkyl group having 1 to 4 carbon atoms (-CH ₂ contained in the alkyl group - it is, -O- or -CO- in may also have been replaced) or a, ^{R 2} and ^{R 3} together Then, together with the carbon atom to which they are bonded, a single bond or an alkanediyl bridge having 1 to 4 carbon atoms (-CH ₂ − contained in the alkanediyl bridge is -O-, -S-, -CO-,- SO- or -SO ₂ -. which may be substituted with) more preferable to form a
Fluorine atom or an alkyl group having 1 to 3 carbon atoms (-CH ₂ contained in the alkyl group - it is, -O- or -CO- in may also have been replaced) or a, ^{R 2} and ^{R 3} together Then, together with the carbon atom to which they are bonded, a single bond or an alkanediyl bridge having 1 to 3 carbon atoms (-CH ₂ − contained in the alkanediyl bridge is -O-, -S-, -CO-,- It may be replaced with SO − or − SO ₂₋ ), which is even more preferable.

The alkanediyl group in L ¹ includes a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, and a hexane-1,6-diyl group. Linear alkanediyl groups such as 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. Alkanediyl group and the like can be mentioned.
L ¹ is preferably a methylene group, an ethylene group or a propylene group, more preferably a methylene group or an ethylene group, and even more preferably a methylene group.
-L ¹ -CO-O ^- bonding positions, it is preferred for bonding positions of ^{S +,} which is the o-position.

Examples of the salt (I) include compounds represented by the following formulas.

[Method for producing salt (I)]
The salt (I) can be obtained by mixing the salt represented by the formula (Ia) in a solvent under a base catalyst.
(In the formula, all the symbols have the same meanings as described above.)
Examples of the base include triethylamine, sodium hydroxide, potassium hydroxide and the like.
Examples of the solvent include chloroform and the like.
The reaction is usually carried out in the temperature range of 0 to 80 ° C. for 0.5 to 24 hours.

The salt represented by the formula (Ia) is prepared by combining a compound represented by the formula (Ib) and a compound represented by the formula (Ic) with trifluoromethanesulfonic acid and trifluoroacetic anhydride. It can be obtained by reacting in a solvent in the presence of.
(In the formula, all the symbols have the same meanings as described above.)
Examples of the solvent include chloroform, acetonitrile and the like.
The reaction is usually carried out in the temperature range of 0 to 60 ° C. for 0.5 to 24 hours.
Examples of the compound represented by the formula (Ib) include compounds represented by the following formula, which can be easily obtained from the market and can be easily produced by a known production method.
Examples of the compound represented by the formula (Ic) include compounds represented by the following formula, which can be easily obtained from the market.

[Quencher]
The citrate of the present invention contains salt (I). The quencher may contain one kind of salt (I), or may contain two or more kinds of salt (I).
In addition to the salt (I), the citric acid of the present invention may contain a citric acid known in the field of resist (hereinafter, may be referred to as "citric acid (C)"). The quencher (C) may be used alone or in combination of two or more.

<Quencher (C)>
The quencher (C) is represented by a salt that generates an acid having a weaker acidity than that generated from a basic nitrogen-containing organic compound and an acid generator (B) described later (however, represented by the formula (I)). Excluding salt.) Among them, it contains a salt that generates an acid having a weaker acidity than the acid generated from the acid generator (B) such as a weak acid intramolecular salt (hereinafter sometimes referred to as “weak acid intramolecular salt (D)”). It is preferable to have.
Examples of the basic nitrogen-containing organic compound include amine and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines.

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, trypentylamine, trihexylamine, tri Heptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, Ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, tri Isopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3 , 3'-diethyldiphenylmethane, 2,2'-methylenebisaniline, imidazole, 4-methylimidazole, pyridine, 4-methylpyridine, 1,2-di (2-pyridyl) ethane, 1,2-di (4-di) Pyridyl) ethane, 1,2-di (2-pyridyl) ethene, 1,2-di (4-pyridyl) ethane, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyloxy) ) Ethan, di (2-pyridyl) ketone, 4,4'-dipyridyl sulfide, 4,4'-dipyridyl disulfide, 2,2'-dipyridylamine, 2,2'-dipicorylamine, bipyridine and the like. Diisopropylaniline is preferable, and 2,6-diisopropylaniline is more preferable.

Ammonium salts include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3- (trifluoromethyl) phenyltrimethyl. Examples thereof include ammonium hydroxide, tetra-n-butylammonium salicylate and choline.

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

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

When the salt (I) and the quencher (C) are contained as the quencher, the ratio of the contents of the salt (I) and the quencher (C) (mass ratio; salt (I): quencher (C)) Is usually 1:99 to 99: 1, preferably 2:98 to 98: 2, more preferably 5:95 to 95: 5, and even more preferably 10:90 to 90:10. Yes, especially preferably 15:85-85:15.

[Resist composition]
The resist composition of the present invention includes a quencher containing a salt (I), a resin containing a structural unit having an acid unstable group (hereinafter sometimes referred to as “resin (A)”), and an acid generator (hereinafter referred to as “acid generation”). Agent (B) "is sometimes referred to). Here, the "acid-unstable group" means a group having a leaving group, which is removed by contact with an acid to form a hydrophilic group (for example, a hydroxy group or a carboxy group). ..
The resist composition of the present invention preferably contains a solvent (hereinafter sometimes referred to as "solvent (E)").

<Quencher>
In the resist composition of the present invention, the content of the salt (I) is usually 0.001 to 20% by mass, preferably 0.005 to 15% by mass, more preferably 0.005 to 15% by mass, based on the solid content of the resist composition. It is 0.01 to 10% by mass. When the quencher contains the quencher (C), the content of the quencher (C) is preferably about 0.01 to 15% by mass, preferably 0.01, based on the solid content of the resist composition. It is more preferably about 10% by mass, further preferably about 0.01 to 5% by mass, and even more preferably about 0.01 to 3% by mass.

<Resin (A)>
The resin (A) has a structural unit having an acid unstable group (hereinafter, may be referred to as “structural unit (a1)”). The resin (A) preferably further contains a structural unit other than the structural unit (a1). Structural units other than the structural unit (a1) include structural units having no acid-labile group (hereinafter sometimes referred to as "structural unit (s)"), structural units (a1), and structural units other than the structural unit (s). A structural unit (for example, a structural unit having a halogen atom described later (hereinafter sometimes referred to as “structural unit (a4)”) and a structural unit having a non-desorbed hydrocarbon group described later (hereinafter referred to as “structural unit (a5)”). In some cases) and other structural units derived from monomers known in the art.

<Structural unit (a1)>
The structural unit (a1) is derived from a monomer having an acid unstable group (hereinafter, may be referred to as “monomer (a1)”).
The acid-unstable group contained in the resin (A) is a group represented by the formula (1) (hereinafter, also referred to as a group (1)) and / or a group represented by the formula (2) (hereinafter, a group (2). ) Is also preferable.
[In the formula (1), R ^a1 , R ^a2, and R ^a3 independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a group combining these groups. R ^a1 and R ^a2 are bonded to each other to form an alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.
ma and na independently represent 0 or 1, and at least one of ma and na represents 1.
* Represents the binding site. ]
[In the formula (2), R ^a1'and R ^a2' each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^a3' represents a hydrocarbon group having 1 to 20 carbon atoms. Represented, R ^a2'and R ^a3' are bonded to each other to form a heterocyclic group having 3 to 20 carbon atoms together with the carbon atom and X to which they are bonded, and are contained in the hydrocarbon group and the heterocyclic group-. CH _2- may be replaced by −O− or −S−.
X represents an oxygen atom or a sulfur atom.
na'represents 0 or 1.
* Represents the binding site. ]

^Examples of the alkyl group in R ^a1 , R ^a2 and R ^a3 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an 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 (* indicates a binding site). The alicyclic hydrocarbon groups of R ^a1 , R ^a2 and R ^a3 have preferably 3 to 16 carbon atoms.
Examples of the group in which the alkyl group and the alicyclic hydrocarbon group are combined include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, an adamantyldimethyl group and a norbornyl group. Examples include an ethyl group.
Preferably, ma is 0 and na is 1.
Examples of -C (R ^a1 ) (R ^a2 ) (R ^a3 ) in the case where R ^a1 and R a ² are bonded to each other to form an alicyclic hydrocarbon group include the following groups. The alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms. * Represents the binding site with -O-.

Examples of the hydrocarbon group in 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 the alicyclic hydrocarbon group include the same groups as those mentioned in R ^a1 , R ^a2 and R ^a3 .
Examples of the aromatic hydrocarbon group include an aryl group such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group and a phenanthryl group.
Examples of the combined group include a group combining the above-mentioned alkyl group and alicyclic hydrocarbon group (cycloalkylalkyl group, etc.), an aralkyl group such as a benzyl group, and an aromatic hydrocarbon group having an alkyl group (p-methyl). Phenyl group, p-tert-butylphenyl group, trill group, xsilyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.), alicyclic hydrocarbon group Examples thereof include an aromatic hydrocarbon group (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.), an aryl-cycloalkyl group (phenylcyclohexyl group, etc.) and the like.
When R ^a2'and R ^a3'bond to each other to form a heterocyclic group with the carbon atom and X to which they are bonded, -C (R ^a1' ) (R ^a2' )-X-R ^a3' The following groups can be mentioned. * Represents the binding site.
Of R ^{a1 'and} R ^a2', it is preferable that at least one is a hydrogen atom.
na'is preferably 0.

A group in which R ^a1 , R ^a2, and R ^a3 are alkyl groups in the formula (1), ma = 0, and na = 1. As the group, a tert-butoxycarbonyl group is preferable.
In formula (1), R ^a1 and R ^a2 form an adamantyl group together with the carbon atom to which they are bonded, and R ^a3 is an alkyl group, ma = 0, and na = 1. ..
In the formula (1), R ^a1 and R ^a2 are independently alkyl groups, R ^a3 is an adamantyl group, ma = 0, and na = 1.
Specific examples of the group (1) include the following groups. * Represents the binding site.

Specific examples of the group (2) include the following groups. * Represents the binding site.

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

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

As the structural unit derived from the (meth) acrylic monomer having the group (1), the structural unit represented by the formula (a1-0) (hereinafter, may be referred to as the structural unit (a1-0)), the formula ( The structural unit represented by a1-1) (hereinafter, may be referred to as a structural unit (a1-1)) or the structural unit represented by the formula (a1-2) (hereinafter, referred to as a structural unit (a1-2)). In some cases.) Preferably, it is at least one structural unit selected from the group consisting of the structural unit (a1-1) and the structural unit (a1-2). These may be used alone or in combination of two or more.
[In the formula (a1-0), the formula (a1-1) and the formula (a1-2),
L ^a01, L ^a1 and L ^a2 each independently, -O- or _{* -O- (CH 2) k1 -CO} -O- the stands, k1 represents an integer of 1-7, and * Represents the binding site with −CO−.
R ^a01 , R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a02 , R ^a03 and R ^a04 independently ^represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group combining these groups.
R ^a6 and R ^a7 independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group formed by combining them.
m1 represents any integer from 0 to 14.
n1 represents any integer from 0 to 10.
n1'represents an integer of 0 to 3. ]

R ^a01 , R ^a4 and R ^a5 are preferably methyl groups.
L ^a01, L ^a1 and L ^a2 are preferably oxygen atom or _{* -O- (CH 2) k01 -CO} -O- and is (however, k01 is preferably either 1 to 4 integer, more preferably Is 1.), More preferably an oxygen atom.
Alkyl groups, alicyclic hydrocarbon groups in R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 and groups combining these are the groups listed in R ^a1 , R ^a2 and R ^a3 of the formula (1). The same group as.
The alkyl group in R ^a02 , R ^a03 , and R ^a04 is preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group, and further preferably a methyl group.
The alkyl group in R ^a6 and R ^a7 is preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group or an isopropyl group, and further preferably an ethyl group or an isopropyl group.
The alicyclic hydrocarbon groups of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 have preferably 5 to 12 carbon atoms, more preferably 5 to 10 carbon atoms.
The group in which the alkyl group and the alicyclic hydrocarbon group are combined preferably has a total carbon number of 18 or less in combination with these alkyl groups and the alicyclic hydrocarbon group.
R ^a02 and R ^a03 are preferably alkyl groups having 1 to 6 carbon atoms, and more preferably methyl groups or ethyl groups.
R ^a04 is preferably an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 5 to 12 carbon atoms, and more preferably a methyl group, an ethyl group, a cyclohexyl group or an 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 further 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, and more preferably 0 or 1.
n1'is preferably 0 or 1.

The structural unit (a1-0) includes, for example, the structural unit represented by any of the formulas (a1-0-1) to (a1-0-12) and R ^a01 in the structural unit (a1-0). Examples thereof include structural units in which the corresponding methyl group is replaced with a hydrogen atom, and structural units represented by any of the formulas (a1-0-1) to (a1-0-10) are preferable.

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

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

When the resin (A) contains the structural unit (a1-0), the content thereof is usually 5 to 60 mol%, preferably 5 to 50 mol%, based on all the structural units of the resin (A). Yes, more preferably 10-40 mol%.
When the resin (A) contains structural units (a1-1) and / or structural units (a1-2), the total content of these is usually 10 to 95 mol with respect to all the structural units of the resin (A). %, Preferably 15-90 mol%, more preferably 20-85 mol%, even more preferably 25-75 mol%, even more preferably 30-70 mol%.

Examples of the structural unit having the group (2) in the structural unit (a1) include a structural unit represented by the formula (a1-4) (hereinafter, may be referred to as “structural unit (a1-4)”). ..
[In equation (a1-4),
R ^a32 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a33 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, and 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 Ra ^33s may be the same or different from each other.
R ^a34 and R ^a35 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^a36 may represent a hydrocarbon group having 1 to 20 carbon atoms, R ^a35 and R ^a36 are bonded to each other Then, together with -CO- to which they are bonded, a divalent hydrocarbon group having 2 to 20 carbon atoms is formed, and the hydrocarbon group and −CH ₂ − contained in the divalent hydrocarbon group are − It may be replaced by O- or -S-. ]

^Examples of the alkyl group in 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 in 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 a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, and 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, 2,2,3,3,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group, etc. Can be mentioned.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group and a hexyloxy group. Of these, an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is even more preferable.
Examples of the 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.
As the hydrocarbon group for R ^a34, R ^a35 and R ^a36, an alkyl group, an alicyclic hydrocarbon group, aromatic hydrocarbon group and a group formed by combining these.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group and the like.
The alicyclic hydrocarbon group may be either a monocyclic or polycyclic group. 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 (* indicates a binding site).
Examples of the aromatic hydrocarbon group include an aryl group such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group and a phenanthryl group.
Examples of the combined group include a group combining the above-mentioned alkyl group and alicyclic hydrocarbon group (for example, cycloalkylalkyl group), an aralkyl group such as a benzyl group, and an aromatic hydrocarbon group having an alkyl group (p-methyl). Phenyl group, p-tert-butylphenyl group, trill group, xsilyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.), alicyclic hydrocarbon group Examples thereof include an aromatic hydrocarbon group (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.), an aryl-cycloalkyl group such as a phenylcyclohexyl group, and the like. In particular, ^Ra36 includes an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group formed by combining these groups. Can be mentioned.

In the formula (a1-4), a hydrogen atom is preferable as ^Ra32 .
As R ^a33 , an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group and an ethoxy group are more preferable, and a methoxy group is further preferable.
As la, 0 or 1 is preferable, and 0 is more preferable.
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, and 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. It is a group to be formed, more preferably 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 the alicyclic hydrocarbon group in ^Ra36 are preferably unsubstituted. Aromatic hydrocarbon group for R ^a36 is an aromatic ring preferably has an aryloxy group having 6 to 10 carbon atoms.

^{-OC (R a34) (R a35} ) -O-R a36 in the structural unit (a1-4) is desorbed by contact with an acid (e.g. p- toluenesulfonic acid) to form a hydroxy group.

Examples of the structural unit (a1-4) include a structural unit derived from a monomer described in JP-A-2010-204646. Preferably, hydrogen atom corresponding to R ^a32 in equation (a1-4-1) represented respectively to Formula (a1-4-12) structural units and structural units (a1-4) is replaced by a methyl group structure Units are mentioned, and more preferably, structural units represented by the formulas (a1-4-1) to (a1-4-5) and (a1-4-10) are mentioned.

When the resin (A) has a structural unit (a1-4), the content thereof is preferably 10 to 95 mol% with respect to the total of all the structural units of the resin (A), 15 to 90. It is more preferably mol%, further preferably 20 to 85 mol%, even more preferably 20 to 70 mol%, and particularly preferably 20 to 60 mol%.

Examples of the structural unit derived from the (meth) acrylic monomer having the group (2) include a structural unit represented by the formula (a1-5) (hereinafter, may be referred to as “structural unit (a1-5)”). Be done.
In equation (a1-5),
R ^a8 represents an alkyl group having 1 to 6 carbon atoms, a hydrogen atom or a halogen atom which may have a halogen atom.
Z ^a1 represents a single bond or _{* - (CH 2) h3 -CO} -L 54 - represents, h3 represents an integer of 1 to 4, * represents a binding site with L ^51.
L ⁵¹ , L ⁵² , L ⁵³ and L ⁵⁴ independently represent -O- or -S-, respectively.
s1 represents an integer of 1 to 3.
s1'represents an integer of 0 to 3.

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

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

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

Moreover, the following structural unit is also mentioned as a structural unit (a1).

When the resin (A) contains structural units such as (a1-3-1) to (a1-3-7), the content thereof is 10 to 10 with respect to all the structural units of the resin (A). 95 mol% is preferable, 15 to 90 mol% is more preferable, 20 to 85 mol% is further preferable, 20 to 70 mol% is further more preferable, and 20 to 60 mol% is particularly preferable.

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

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

Examples of the structural unit having a phenolic hydroxy group in the structural unit (a2) include a structural unit represented by the formula (a2-A) (hereinafter, may be referred to as “structural unit (a2-A)”).
[In formula (a2-A),
^Ra50 represents an alkyl group having 1 to 6 carbon atoms which may have a hydrogen atom, a halogen atom or a halogen atom.
^Ra51 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, and acryloyl. Represents an oxy group or a methacryloyloxy group.
A ^a50 represents a single bond or ^{* -X a51 - (A a52 -X} a52) nb - represents, * represents a binding site to the carbon atom to which -R ^a50 binds.
A ^a52 represents an alkanediyl group having 1 to 6 carbon atoms.
X ^a51 and X ^a52 independently represent -O-, ^-CO -O- or -O-CO-, respectively.
nb represents 0 or 1.
mb represents any integer from 0 to 4. When mb is any integer of 2 or more, the plurality of Ra ^51s may be the same as or different from each other. ]

^Examples of the halogen atom in ^Ra50 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 in ^Ra50 include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group and 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, 2,2,3,3,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group and perfluorohexyl Group is mentioned.
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 in ^Ra51 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group.
^Examples of the alkoxy group in ^Ra51 include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, and a tert-butoxy group. An alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is further preferable.
^Examples of the alkylcarbonyl group in ^Ra51 include an acetyl group, a propionyl group, a butyryl group and the like.
^Examples of the alkylcarbonyloxy group in ^Ra51 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- is * ^-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 -, Can be mentioned. Of these, * -CO-O-, * -CO-O-A ^a52- CO-O- or * -O-A ^a52- CO-O- are preferable.

The alkanediyl group includes a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, and a hexane-. 1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group and 2 -Methylbutane-1,4-diyl group and the like can be mentioned.
A ^a52 is preferably a methylene group or an ethylene group.

A ^a50 is preferably single bond, * -CO-O- or * -CO-O-A ^a52- CO-O-, single bond, * -CO-O- or * -CO-O-CH. It is more preferably _2- CO-O-, and even more preferably a single bond or * -CO-O-.

The 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-position or para-position of the benzene ring, and more preferably to the para-position.

Examples of the structural unit (a2-A) include monomer-derived structural units described in JP-A-2010-204634 and JP-A-2012-12577.
As the structural unit (a2-A), the structural unit represented by the formulas (a2-2-1) to (a2-2-6) and the formulas (a2-2-1) to (a2-2-6) are used. In the structural unit represented by), a structural unit in which the methyl group corresponding to ^Ra50 in the structural unit (a2-A) is replaced with a hydrogen atom can be mentioned. The structural unit (a2-A) is represented by a structural unit represented by the formula (a2-2-1), a structural unit represented by the formula (a2-2-3), and a formula (a2-2-6). In the structural unit represented by the formula (a2-2-1), the structural unit represented by the formula (a2-2-3), and the structural unit represented by the formula (a2-2-6). It is preferable that the methyl group corresponding to ^Ra50 in the structural unit (a2-A) 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. It is 10 to 70 mol%, more preferably 15 to 65 mol%, and even more preferably 20 to 65 mol%.
The structural unit (a2-A) can be included in the resin (A) by, for example, polymerizing using the structural unit (a1-4) and then treating with an acid such as p-toluenesulfonic acid. Further, the structural unit (a2-A) can be contained in the resin (A) by polymerizing with acetoxystyrene or the like and then treating with an alkali such as tetramethylammonium hydroxide.

Examples of the structural unit having an alcoholic hydroxy group in the structural unit (a2) include a structural unit represented by the formula (a2-1) (hereinafter, may be referred to as “structural unit (a2-1)”).
In equation (a2-1),
^La3 represents −O− or * −O− (CH ₂ ) _k2 −CO−O−.
k2 represents any integer from 1 to 7. * Represents the binding site 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.

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

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

When the resin (A) contains the structural unit (a2-1), the content thereof is usually 1 to 45 mol%, preferably 1 to 40 mol%, based on all the structural units of the resin (A). It is more preferably 1 to 35 mol%, further preferably 1 to 20 mol%, and even more preferably 1 to 10 mol%.

<Structural unit (a3)>
The lactone ring of the structural unit (a3) may be a monocyclic ring such as β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, or a fused ring of a monocyclic lactone ring and another ring. But it may be. Preferably, a γ-butyrolactone ring, an adamantane lactone ring, or a bridged ring containing a γ-butyrolactone ring structure (for example, a structural unit represented by the following formula (a3-2)) can be mentioned.

The structural unit (a3) is preferably a structural unit represented by the formula (a3-1), the formula (a3-2), the formula (a3-3), or the formula (a3-4). One of these may be contained alone, or two or more thereof may be contained.
[In the formula (a3-1), the formula (a3-2), the formula (a3-3) and the formula (a3-4),
^La4 , ^La5, and ^La6 are independently represented by -O- or * -O- (CH ₂ ) _k3 -CO-O- (k3 represents an integer of 1 to 7). Represents a group.
L ^a7 is, -O -, * - O- L a8 -O -, * - O-L a8 -CO-O -, * - O-L a8 -CO-O-L a9 -CO-O- or * Represents −O−L ^a8 −O−CO−L ^a9 −O−.
^{La 8} and ^{La 9} each independently represent an alkanediyl group having 1 to 6 carbon atoms.
* Represents the binding site with the 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, a hydrogen atom or a halogen atom which may have 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, a plurality of R ^a21 , R ^a22 , R ^a23 and / or R ^a25 may be the same as or different from each other. ]

Examples of the aliphatic hydrocarbon group in R ^a21 , R ^a22 , R ^a23 and R ^a25 include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group and tert-butyl group. Be done.
Examples of the halogen atom in ^Ra24 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
^Examples of the alkyl group in ^Ra24 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group, and preferably have 1 to 4 carbon atoms. Alkyl group of, more preferably methyl group or ethyl group.
Alkyl groups having a halogen atom in ^Ra24 include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group and perfluoro. Examples thereof include a hexyl group, a trichloromethyl group, a tribromomethyl group, and a triiodomethyl group.
The alkanediyl groups in ^La8 and ^La9 include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, and pentane-1,5. -Diyl group, hexane-1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1, Examples thereof include 4-diyl group and 2-methylbutane-1,4-diyl group.

Formula (a3-1) ~ formula ^{(a3-3), L a4, L} a5 and L ^a6 are each independently preferably -O- _{or, * - O- (CH 2)} k3 -CO-O- In, a group in which k3 is an integer of any of 1 to 4, more preferably -O- and * -O-CH _2- CO-O-, still more preferably an oxygen atom.
R ^a18 , R ^a19 , R ^a20 and R ^a21 are preferably methyl groups.
R ^a22 and R ^a23 are each independently, preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are independently, preferably an integer of 0 to 2, and more preferably 0 or 1.

In the 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, more preferably a hydrogen atom or a methyl group Is.
R ^a25 is preferably a carboxy group, a cyano group or a methyl group.
L ^a7 is preferably -O- or * -O-L ^a8 -CO-O-, more preferably an _{-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, the formula (a3-4) is preferably the formula (a3-4)'.
(In the formula, R ^a24 and ^{La 7} have the same meanings as above.)

The structural unit (a3) is a structure derived from the monomer described in JP-A-2010-204646, the monomer described in JP-A-2000-122294, and the monomer described in JP-A-2012-41274. The unit is mentioned. The structural unit (a3) includes the formula (a3-1-1), the formula (a3-1-2), the formula (a3-2-1), the formula (a3-2-2), and the formula (a3-3-3). 1), the structural unit represented by any of the formulas (a3-3-2) and the formulas (a3-4-1) to (a3-4-12), and in the structural unit, the formula (a3-1). ) R ^a18 in ~ formula ^{(a3-4), R a19, R} a20 and structural units in which a methyl group is replaced by a hydrogen atom corresponding to R ^a24 are preferred.

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

<Structural unit (a4)>
Examples of the structural unit (a4) include the following structural units.
[In equation (a4),
R ⁴¹ represents a hydrogen atom or a methyl group.
R ⁴² represents a saturated hydrocarbon group having a fluorine atom having 1 to 24 carbon atoms, 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.

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 the monocyclic or polycyclic alicyclic hydrocarbon group 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 thereof include a polycyclic alicyclic hydrocarbon group such as (* represents a binding site).
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, and examples thereof include-alkanediyl groups-. Examples thereof include an alicyclic hydrocarbon group, an alicyclic hydrocarbon group, an alkyl group, an alkanediyl group, an alicyclic hydrocarbon group, and an alkyl group.

The structural unit (a4) is at least selected from the group consisting of the formula (a4-0), the formula (a4-1), the formula (a4-2), the formula (a4-3), and the formula (a4-4). A structural unit represented by one can be mentioned.
[In equation (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. ]

The divalent aliphatic saturated hydrocarbon group in L ^4a includes a linear alcandiyl group such as a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, and an ethane-1. , 1-diyl group, propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group and the like. Alcandiyl group is mentioned.
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. -2,2-diyl group, perfluorobutane-1,4-diyl group, perfluorobutane-2,2-diyl group, perfluorobutane-1,2-diyl group, perfluoropentane-1,5-diyl group, perfluoropentane -2,2-diyl group, perfluoropentane-3,3-diyl group, perfluorohexane-1,6-diyl group, perfluorohexane-2,2-diyl group, perfluorohexane-3,3-diyl group, perfluoroheptane -1,7-diyl group, perfluoroheptane-2,2-diyl group, perfluoroheptane-3,4-diyl group, perfluoroheptane-4,4-diyl group, perfluorooctane-1,8-diyl group, perfluorooctane Examples thereof include -2,2-diyl group, perfluorooctane-3,3-diyl group, perfluorooctane-4,4-diyl group and the like.
^Examples of the perfluorocycloalkandyl group in L ^3a include a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, a perfluoroadamantandiyl group and the like.

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

The structural unit (a4-0), a methyl group corresponding to R ⁵ may be mentioned a structural unit replacing a hydrogen atom in the structural units in the structural units and the following structural units shown below (a4-0).

[In equation (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 may.
A ^a41 represents an alkanediyl group having 1 to 6 carbon atoms which may have a substituent or a group represented by the formula ( ^ag1 ). However, at least one of A ^a41 and R ^a42 has a halogen atom (preferably a fluorine atom) as a substituent.
[In the formula (ag1),
s represents 0 or 1.
A ^a42 and A ^a44 each independently represent a divalent 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 independently represent -O-, -CO-, ^-CO -O- or -O-CO-, respectively.
However, the total number of carbon atoms of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 7 or less. ]
* Is the binding site, and * on the right is the binding site with -O-CO-R ^a42 . ]

^Examples of the saturated hydrocarbon group in ^Ra42 include a chain-type saturated hydrocarbon group, a monocyclic or polycyclic alicyclic saturated hydrocarbon group, and a group formed by combining these.
The chain saturated hydrocarbon group includes 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 the monocyclic or polycyclic alicyclic saturated hydrocarbon group include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group and the following. Examples thereof include a polycyclic alicyclic saturated hydrocarbon group such as a group (* represents a binding site).
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 saturated hydrocarbon groups, and a-alkandyl group. -Alicyclic saturated hydrocarbon group, -Alicyclic saturated hydrocarbon group-alkyl group, -Alkanediyl group-Alicyclic saturated hydrocarbon group-alkyl group and the like.

^Examples of the substituent ^{contained in} R ^a42 include at least one selected from a halogen atom and a group represented by the formula ( ^ag3 ). Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.
[In the formula (ag3),
X ^a43 represents an oxygen atom, a carbonyl group, * ^-O -CO- or * -CO-O-.
A ^a45 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
* Represents the binding site with ^Ra42 . ]
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 having at least one halogen atom.

The aliphatic hydrocarbon group in A ^a45 includes 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 Examples thereof include a polycyclic alicyclic hydrocarbon group such as (* represents a binding site).
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, and examples thereof include-alkanediyl groups-. Examples thereof include an alicyclic hydrocarbon group, an alicyclic hydrocarbon group, an alkyl group, an alkanediyl group, an alicyclic hydrocarbon group, and an alkyl group.

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

When R ^a42 is an aliphatic hydrocarbon having a group represented by the formula ( ^ag3 ), R ^a42 is more preferably a group represented by the formula ( ^ag2 ).
[In the formula (ag2),
A ^a46 represents 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 the binding site 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 the binding site with the carbonyl group. ]

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

The preferred structure of the group represented by the formula (ag2) is the following structure (* is a binding site with a carbonyl group).

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

The divalent saturated hydrocarbon group represented by A ^a42 , A ^a43 and A ^{a44 in} the group represented by the formula (a-g1) includes a linear or branched alkandiyl group and a monocyclic divalent alicyclic group. Examples thereof include a hydrocarbon group and a group formed by combining an alcandiyl 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 thereof include 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.
^Examples of the substituent of 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.
s is preferably 0.

In the group represented by the formula (a-g1), ^{examples of the} group in which X ^a42 is -O-, ^-CO- , ^-CO -O- or -O-CO- include the following groups. In the following examples, * and ** represent the binding site, respectively, and ** is the binding site with -O-CO-R ^a42 .

As the structural unit represented by the formula (a4-1), the methyl group corresponding to ^Ra41 in the structural unit shown below and the structural unit represented by the formula (a4-1) in the following structural unit is a hydrogen atom. Examples include replaced structural units.

As the structural unit represented by the formula (a4-1), the structural unit represented by the formula (a4-2) is preferable.
[In equation (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 a fluorine atom having 1 to 20 carbon atoms.
However, the upper limit of the total carbon number of L ⁴⁴ and R ^f6 is 21. ]

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

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

Examples of the structural unit (a4) include a structural unit represented by the formula (a4-3).
[In equation (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 the binding site 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 carbon number of L ⁵ , A ^f13 and A ^f14 is 20. ]

^Examples of the alkanediyl group in L ⁵ include the same groups as those exemplified in the alkanediyl group in the divalent saturated hydrocarbon group of A ^a41 .
The divalent saturated hydrocarbon group which may have a fluorine atom in A ^f13 preferably has a divalent aliphatic saturated hydrocarbon group which may have a fluorine atom and a fluorine atom. It is also a good divalent alicyclic saturated hydrocarbon group, more preferably a perfluoroalkanediyl group.
Examples of the divalent aliphatic hydrocarbon group which may have a fluorine atom include an alkanediyl group such as a methylene group, an ethylene group, a propanediyl group, a butanjiyl group and a pentandiyl group; a difluoromethylene group, a perfluoroethylene group and a perfluoro Examples thereof include a perfluoroalkandyl group such as a propanediyl group, a perfluorobutandyl group and a perfluoropentanediyl group.
The divalent alicyclic hydrocarbon group which may have a fluorine atom may be either a monocyclic type or a polycyclic type. Examples of the monocyclic group include a cyclohexanediyl group and a perfluorocyclohexanediyl group. Examples of the polycyclic group include an adamantandiyl group, a norbornanediyl group, a perfluoroadamantandiyl group and the like.
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 in ^Ra42 . 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, 2,2,3,3,4,5,5,5-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 and the like are preferable.

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

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

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

^Examples of the saturated hydrocarbon group of R ^f22 include the same saturated hydrocarbon group represented by R ^a42 . R ^f22 is preferably an alkyl group having 1 to 10 carbon atoms having a fluorine atom or an alicyclic hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom, and an alkyl group having 1 to 10 carbon atoms having a fluorine atom is more preferable. Preferably, an alkyl group having 1 to 6 carbon atoms having a fluorine atom is more preferable.

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

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

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

<Structural unit (a5)>
Examples of the non-eliminating hydrocarbon group contained in the structural unit (a5) include a group having a linear, branched or cyclic hydrocarbon group. Among them, 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 the formula (a5-1).
[In equation (a5-1),
R ⁵¹ represents a hydrogen atom or a methyl group.
R ⁵² represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms. ..
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 in R ⁵² may be either a monocyclic or polycyclic group. Examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group. Examples of the polycyclic alicyclic hydrocarbon group include an adamantyl group and a norbornyl group.
The aliphatic hydrocarbon group having 1 to 8 carbon atoms includes, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group and 2 -Alkyl groups such as ethylhexyl groups can be mentioned.
Examples of the alicyclic hydrocarbon group having a substituent include a 3-methyladamantyl group.
R ⁵² is preferably an unsubstituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and more preferably an adamantyl group, a norbornyl group or a cyclohexyl group.
Examples of the divalent saturated hydrocarbon group in L ⁵⁵ include a divalent chain-type saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, and a divalent chain-type saturated hydrocarbon group is preferable. ..
Examples of the divalent chain saturated hydrocarbon group include an alkanediyl group such as a methylene group, an ethylene group, a propanediyl group, a butanjiyl group and a pentandiyl group.
The divalent alicyclic saturated hydrocarbon group may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic saturated hydrocarbon group include a cycloalkanediyl group such as a cyclopentanediyl group and a cyclohexanediyl group. Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include an adamantandiyl group and a norbornanediyl group.

Examples of the group in which -CH _2- contained in the divalent saturated hydrocarbon group represented by L ⁵⁵ is replaced with -O- or -CO- are represented by the formulas (L1-1) to (L1-4). The groups represented are mentioned. In the following formula, * and ** represent the binding sites, respectively, and * represents the binding site with the oxygen atom.
In formula (L1-1),
X ^x1 represents * -O-CO- or * -CO-O- (* represents the binding site 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 number of carbon atoms of L ^x1 and L ^x2 is 16 or less.
In formula (L1-2),
L ^x3 represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms.
L ^x4 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
However, the total number of carbon atoms of L ^x3 and L ^x4 is 17 or less.
In formula (L1-3),
L ^x5 represents a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^x6 and L ^x7 each independently represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms.
However, the total number of carbon atoms of L ^x5 , L ^x6 and L ^x7 is 15 or less.
In formula (L1-4),
L ^x8 and L ^x9 represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms.
W ^{x 1} represents a divalent alicyclic saturated hydrocarbon group having 3 to 15 carbon atoms.
However, the total number of carbon atoms of L ^x8 , L ^x9 and W ^x1 is 15 or less.

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

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

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

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

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

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

Examples of the structural unit (a5-1) include the structural unit shown below and the structural unit in which the methyl group corresponding to R ⁵¹ in the structural unit (a5-1) in the following structural unit is replaced with a hydrogen atom.
When the resin (A) has a structural unit (a5), the content thereof is preferably 1 to 30 mol%, more preferably 2 to 20 mol%, based on all the structural units of the resin (A). More preferably ~ 15 mol%.

<Structural unit (II)>
The resin (A) may further contain a structural unit (hereinafter, may be referred to as “structural unit (II)”) that decomposes by exposure to generate an acid. Specific examples of the structural unit (II) include the structural units described in JP-A-2016-79235, and the structural unit having a sulfonate group or a carboxylate group and an organic cation in the side chain or sulfonio in the side chain. It is preferably a structural unit having a group and an organic anion.

The structural unit having a sulfonate group or a carboxylate group in the side chain is preferably a structural unit represented by the 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 have 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 an alkyl group having 1 to 6 carbon atoms which may have a hydrogen atom, a halogen atom or 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.
As the alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^III3, the alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^a8 The same can be mentioned.
The alkanediyl group having 1 to 8 carbon atoms represented by A ^x1 includes 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.
The perfluoroalkyl group carbon atoms which may be have 1-6 substituents in A ^X1, trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, a perfluoro sec- butyl group, perfluoro tert -Butyl group, perfluoropentyl group, perfluorohexyl group and the like can be mentioned.
Examples of the divalent saturated hydrocarbon group having 1 to 18 carbon atoms represented by X ^III3 include a linear or branched alkanediyl group and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group. These may be a combination thereof.
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, Nonan-1,9-Diyl Group, Decane-1,10-Diyl Group, Undecane-1,11-Diyl Group , Dodecane-1,12-diyl group and other linear alcandiyl groups; butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group , Pentan-1,4-diyl group, 2-methylbutane-1,4-diyl group and other branched alkandiyl groups; cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1 , 4-Diyl group, cyclooctane-1,5-Diyl group and other cycloalkandyl groups; norbornan-1,4-diyl group, norbornan-2,5-diyl group, adamantan-1,5-diyl group, adamantan Examples thereof include a divalent polycyclic alicyclic saturated hydrocarbon group such as −2,6-diyl group.
When -CH _2- contained in the saturated hydrocarbon group is replaced by -O-, -S- or -CO-, for example, a divalent group represented by the formulas (X1) to (X53) is used. Can be mentioned. However, the number of carbon atoms before each of -CH _2- contained in the saturated hydrocarbon group is replaced by -O-, -S- or -CO- is 17 or less. In the following formulas, * and ** represent the binding site, and * represents a binding site with A ^X1.

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

Examples of the organic cation represented by ZA ⁺ include an organic onium cation, an organic sulfonium cation, an organic iodonium cation, an organic ammonium cation, a benzothiazolium cation, and an organic phosphonium cation. Among these, organic sulfonium cations and organic iodonium cations are preferable, and aryl sulfonium cations are more preferable. Specifically, the cation represented by any of the formulas (b2-1) to (b2-4) (hereinafter, may be referred to as "cation (b2-1)" or the like depending on the formula number). Can be mentioned.

In equations (b2-1) to (b2-4),
R ^{b4 to} R ^b6 independently represent a chain hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms. The hydrogen atom contained in the chain hydrocarbon group is a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. It may be substituted, and the hydrogen atom contained in the alicyclic hydrocarbon group is a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms or a glycidyloxy group. It may be substituted, and the hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group or an alkoxy group having 1 to 12 carbon atoms.
R ^b4 and R ^b5 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, and -CH ₂ − contained in the ring may be -O-, -S- or. It may be replaced with −CO−.
R ^b7 and R ^b8 independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0 to 5.
When m2 is 2 or more, the plurality of R ^b7s may be the same or different, and when n2 is 2 or more, the plurality of R ^b8s may be the same or different.
R ^b9 and R ^b10 independently represent a chain hydrocarbon group having 1 to 36 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms.
R ^b9 and R ^b10 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, and -CH ₂ − contained in the ring may be -O-, -S- or. It may be replaced with −CO−.
R ^b11 represents a hydrogen atom, a chain hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^b12 represents a chain hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the chain hydrocarbon group can be used as the chain hydrocarbon group. The contained hydrogen atom may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group may be an alkoxy group having 1 to 12 carbon atoms or 1 carbon atom. It may be substituted with ~ 12 alkylcarbonyloxy groups.
R ^b11 and R ^b12 may form a ring including −CH—CO− to which they are bonded to each other, and −CH ₂₋ contained in the ring is −O−, −S. It may be replaced with − or −CO−.
R ^{b13 to} R ^b18 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
L ^b31 represents a sulfur atom or an oxygen atom.
o2, p2, s2, and t2 each independently represent an integer of 0 to 5.
q2 and r2 each independently represent an integer of 0 to 4.
u2 represents 0 or 1.
When o2 is 2 or more, a plurality of R ^b13s are the same or different, when p2 is 2 or more, a plurality of R ^b14s are the same or different, and when q2 is 2 or more, a plurality of R ^b15s are the same or different. when r2 is 2 or more, plural R ^b16 same or different, when s2 is 2 or more, plural R ^b17 same or different, when t2 is 2 or more, plural R ^b18 same or different different.

The aliphatic hydrocarbon group represents a chain hydrocarbon group and an alicyclic hydrocarbon group.
Examples of the chain hydrocarbon group include an alkyl group of a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group and a 2-ethylhexyl group. Can be mentioned.
In particular, the chain hydrocarbon groups of R ^{b9 to} R ^b12 preferably have 1 to 12 carbon atoms.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon group includes a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cyclo. Cycloalkyl groups such as heptyl group, cyclooctyl group and cyclodecyl group can be mentioned. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups.
In particular, the alicyclic hydrocarbon groups of R ^{b9 to} R ^b12 preferably have 3 to 18 carbon atoms, and more preferably 4 to 12 carbon atoms.

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

Examples of the aromatic hydrocarbon group include aryl groups such as a phenyl group, a biphenyl group, a naphthyl group and a phenanthryl group. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group, and the aromatic hydrocarbon group having a chain hydrocarbon group includes a trill group, a xsilyl group and a cumenyl group. , Mesityl group, p-ethylphenyl group, p-tert-butylphenyl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group and the like, and aromatics having an alicyclic hydrocarbon group. Examples of the hydrocarbon group include a p-cyclohexylphenyl group and a p-adamantylphenyl group.
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 are used. Is preferable.
Examples of the aromatic hydrocarbon group in which the hydrogen atom is substituted with an alkoxy group include a p-methoxyphenyl group.
Examples of the chain hydrocarbon group in which the hydrogen atom is substituted with an aromatic hydrocarbon group include an aralkyl group such as a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group and a naphthylethyl group.

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

The ring formed by R ^b4 and R ^b5 bonding to each other and together with the sulfur atom to which they bond can be monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated. It may be a ring of. Examples of this ring include a ring having 3 to 18 carbon atoms, preferably a ring having 4 to 18 carbon atoms. The ring containing a sulfur atom may be a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring, and examples thereof include the following rings. * Represents the binding site.

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

Among the cations (b2-1) to cations (b2-4), the cation (b2-1) is preferable.
Examples of the cation (b2-1) include the following cations.

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

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

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

The structural unit represented by the formula (II-2-A') is preferably the structural unit represented by the 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 ^{III 2} and R ^III 4 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 ^{III 2} and R ^{III 4} are identical to 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. ]
The R ^III2, R ^III4, Q perfluoroalkyl group having 1 to 6 carbon atoms represented by ^a and Q ^b, include those similar to the perfluoroalkyl group having 1 to 6 carbon atoms represented by below of Q ^b1 ..

The structural unit represented by the formula (II-2-A) is preferably the structural unit represented by the formula (II-2-A-1).
[In formula (II-2-A-1),
^{R III2, R III3, R III4} , Q a, Q b and ZA ⁺ are the same as defined 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 atom contained in the saturated hydrocarbon group may be substituted with a halogen atom or a hydroxy group. ]
Examples of the saturated hydrocarbon group having 1 to 12 carbon atoms represented by R ^III5 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group. Examples thereof include a linear or branched alkyl group such as a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group and a dodecyl group.
Examples of the divalent saturated hydrocarbon group represented by X ^I 2 include those similar to the divalent saturated hydrocarbon group represented by X ^{III 3} .

As the structural unit represented by the formula (II-2-A-1), the structural unit represented by the 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 represent 1 or 2 independently of each other. ]

As the structural unit represented by the formula (II-2-A'), for example, the following structural unit, the group corresponding to the methyl group of R ^III3 is a hydrogen atom, a halogen atom (for example, a fluorine atom) or a halogen atom. Examples thereof include structural units replaced with alkyl groups having 1 to 6 carbon atoms (for example, trifluoromethyl groups, etc.) and structural units described in WO 2012/050015. ZA ⁺ represents an organic cation.

The structural unit having a sulfonio group and an organic anion in the side chain is preferably a structural unit represented by the 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 together with the sulfur atom to which they are bonded.
R ^II4 represents an alkyl group having 1 to 6 carbon atoms which may have a hydrogen atom, a halogen atom or 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 in 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.
As the alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^II4 is an alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^a8 The same 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 by -O-, -S- or -CO-. Specifically, the same divalent saturated hydrocarbon group having 1 to 18 carbon atoms represented by X ^III3 can be mentioned.

As the structural unit containing a cation in the formula (II-1-1), the structural unit represented by the following and the group corresponding to the methyl group of R ^II4 are replaced with hydrogen atom, fluorine atom, trifluoromethyl group and the like. Structural units and the like.

Examples of the organic anion represented by A ⁻ include a sulfonic acid anion, a sulfonylimide anion, a sulfonylmethide anion, and a carboxylic acid anion. The organic anion represented by A ⁻ is preferably a sulfonic acid anion, and the sulfonic acid anion is more preferably an anion contained in a salt represented by the formula (B1) described later.

Examples of the sulfonylimide anion represented by A ⁻ include the following.

Examples of the sulfonylmethide anion include the following.

Examples of the carboxylic acid anion include the following.

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

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

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

The resin (A) is preferably a resin composed of a structural unit (a1) and a structural unit (s), that is, a copolymer of a monomer (a1) and a monomer (s).
The structural unit (a1) is preferably a group consisting of a structural unit (a1-0), a structural unit (a1-1) and a structural unit (a1-2) (preferably the structural unit having a cyclohexyl group and a cyclopentyl group). It is at least one selected from, more preferably at least two, and even more preferably at least two selected from the group consisting of structural units (a1-1) and structural units (a1-2).
The structural unit (s) is preferably at least one selected from the group consisting of the structural unit (a2) and the structural unit (a3). The structural unit (a2) is preferably a structural unit (a2-1) or a structural unit (a2-A). The structural unit (a3) is preferably a group consisting of a structural unit represented by the formula (a3-1), a structural unit represented by the formula (a3-2), and a structural unit represented by the formula (a3-4). At least one 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 (for example, a radical polymerization method) using a monomer that derives these structural units. be able to. The content of each structural unit of the resin (A) can be adjusted by adjusting the amount of the monomer used for the polymerization.
The weight average molecular weight of the resin (A) is preferably 2,000 or more (more preferably 2,500 or more, still more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less, still more preferable. Is 15,000 or less). In the present specification, the weight average molecular weight is a value obtained by gel permeation chromatography under the conditions described in Examples.

<Resin other than resin (A)>
The resist composition of the present invention may be used in combination with a resin other than the resin (A).
Examples of the resin other than the resin (A) include a resin containing a structural unit (a4) or a structural unit (a5) (hereinafter, may be referred to as a resin (X)).
As the resin (X), a resin containing a structural unit (a4) is particularly preferable. That is, it is preferable that the resin contains a structural unit having a fluorine atom.
In the resin (X), the content of the structural unit (a4) is preferably 30 mol% or more, more preferably 40 mol% or more, based on the total of all the structural units of the resin (X). , 45 mol% or more is more preferable.
Examples of the structural unit that the resin (X) may further include include a structural unit (a1), a structural unit (a2), a structural unit (a3), and a structural unit derived from other known monomers. Above all, the resin (X) is preferably a resin composed of only 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 is produced by a known polymerization method (for example, a radical polymerization method) using a monomer for inducing these structural units. can do. The content of each structural unit of the resin (X) can be adjusted by adjusting the amount of the monomer used for the 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 the resin (X) is the same as that of the resin (A).

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

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

<Acid generator (B)>
As the acid generator (B), either a nonionic type or an ionic type may be used. Nonionic acid generators include sulfonate esters (eg 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonate), sulfones (eg disulfone, etc.). Ketosulfone, sulfonyldiazomethane) and the like. As the ionic acid generator, an onium salt containing an onium cation (for example, a diazonium salt, a phosphonium salt, a sulfonium salt, an iodonium salt) is typical. Examples of the onium salt anion include a sulfonic acid anion, a sulfonylimide anion, and a sulfonylmethide anion.
Examples of the acid generator (B) include Japanese Patent Application Laid-Open No. 63-26653, Japanese Patent Application Laid-Open No. 55-164824, Japanese Patent Application Laid-Open No. 62-69263, Japanese Patent Application Laid-Open No. 63-146038, and Japanese Patent Application Laid-Open No. 63-163452. Kaisho 62-153853, Japanese Patent Application Laid-Open No. 63-146029, US Pat. No. 3,779,778, US Pat. No. 3,849,137, German Patent No. 3914407, European Patent No. 126,712, etc. A compound that generates an acid by the radiation described in the above can be used. Moreover, you may use the compound produced by the known method. The acid generator (B) may be used in combination of two or more.

The acid generator (B) is preferably a fluorine-containing acid generator, and more preferably a salt represented by the formula (B1) (hereinafter, may be referred to as “acid generator (B1)”).
[In equation (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 an alicyclic hydrocarbon group having 3 to 24 carbon atoms which may have a methyl group which may have a substituent or a substituent, and is contained in the alicyclic hydrocarbon group. CH ₂ - is, -O -, - S -, - SO 2 - or -CO- may be replaced with.
Z ⁺ represents an organic cation. ]

The perfluoroalkyl groups represented by Q ^b1 and Q ^b2 include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group and Examples thereof include a perfluorohexyl group.
It is preferable that Q ^b1 and Q ^b2 are independently fluorine atoms or trifluoromethyl groups, and it is more preferable that 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 be a group formed by combining two or more of the groups.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1 , 7-Diyl Group, Octane-1,8-Diyl Group, Nonan-1,9-Diyl Group, Decane-1,10-Diyl Group, Undecane-1,11-Diyl Group, Dodecane-1,12-Diyl Group , Tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group and heptadecane-1,17-diyl group. Alcandiyl group;
Ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane- A branched alkanediyl group such as 1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group;
Monocyclic 2 which is a cycloalkanediyl group such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclooctane-1,5-diyl group, etc. Valuable alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbons such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, and adamantane-2,6-diyl group. The group etc. can be mentioned.

Examples of the group in which -CH _2- contained in the divalent saturated hydrocarbon group represented by L ^b1 is replaced with -O- or -CO- include formulas (b1-1) to (b1-3). A group represented by any of the above can be mentioned. In addition, in the groups represented by the formulas (b1-1) to (b1-3) and the groups represented by the formulas (b1-4) to (b1-11) which are specific examples thereof, * and * * Represents the binding site and * represents the binding site with -Y.

[In equation (b1-1),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated hydrocarbon group may be substituted. -CH _2- contained in the hydrocarbon group may be replaced with -O- or -CO-.
However, the total number of carbon atoms of L ^b2 and L ^b3 is 22 or less.
In equation (b1-2),
L ^b4 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated hydrocarbon group may be substituted. -CH _2- contained in the hydrocarbon group may be replaced with -O- or -CO-.
However, the total number of carbon atoms of L ^b4 and L ^b5 is 22 or less.
In equation (b1-3),
L ^b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
L ^b7 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated hydrocarbon group may be substituted. -CH _2- contained in the hydrocarbon group may be replaced with -O- or -CO-.
However, the total number of carbon atoms of L ^b6 and L ^b7 is 23 or less. ]

In the groups represented by the formulas (b1-1) to (b1-3), when -CH ₂ − contained in the saturated hydrocarbon group is replaced with -O- or -CO-, the carbon before the replacement Let the number be the number of carbon atoms of the saturated hydrocarbon group.
Examples of the divalent saturated hydrocarbon group include those similar to the divalent saturated hydrocarbon group of L ^b1 .
L ^b2 is preferably a single bond.
L ^b3 is preferably 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 ¹ is replaced with -O- or -CO- is represented by the formula (b1-1) or the formula (b1-3). Is preferred.

Examples of the group represented by the formula (b1-1) include groups represented by the formulas (b1-4) to (b1-8), respectively.
[In equation (b1-4),
L ^b8 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
In equation (b1-5),
L ^b9 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, 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 number of carbon atoms of L ^b9 and L ^b10 is 20 or less.
In equation (b1-6),
L ^b11 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b12 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. ..
However, the total number of carbon atoms of L ^b11 and L ^b12 is 21 or less.
In equation (b1-7),
L ^b13 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.
L ^b14 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and -CH _2- contained in the divalent saturated hydrocarbon group is replaced with -O- or -CO-. May be good.
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 number of carbon atoms of L ^{b13 to} L ^b15 is 19 or less.
In equation (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 number of carbon atoms 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, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.

Examples of the group represented by the formula (b1-3) include groups represented by the formulas (b1-9) to (b1-11), respectively.
In equation (b1-9),
L ^b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b20 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. May be good. -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 number of carbon atoms of L ^b19 and L ^b20 is 23 or less.
In equation (b1-10),
L ^b21 represents a single bond or a divalent saturated hydrocarbon group having 1 to ²¹ carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b22 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b23 represents a single bond or a divalent saturated hydrocarbon group having 1 to ²¹ carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. May be good. -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 equation (b1-11),
L ^b24 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b25 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b26 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. May be good. -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, L ^b24, the total number of carbon atoms of L ^b25 and L ^b26 is 21 or less.

In addition, in the group represented by the formula (b1-11) from the group represented by the formula (b1-9), when the hydrogen atom contained in the saturated hydrocarbon group is replaced with the alkylcarbonyloxy group, it is replaced. 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, an adamantylcarbonyloxy group and the like.

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

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

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

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

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

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

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

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

Examples of the group represented by the 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 by -O-, -S (O) _2- or -CO-, the number may be one or two or more. Good. Examples of such groups include groups represented by the formulas (Y12) to (Y35) and the formulas (Y39) to (Y43). * Represents the binding site with L ^b1 .
The alicyclic hydrocarbon group represented by Y is preferably Formula (Y1) to Formula (Y20), Formula (Y26), Formula (Y27), Formula (Y30), Formula (Y31), Formula (Y39). A group represented by any of the formulas (Y43), more preferably the formula (Y11), the formula (Y15), the formula (Y16), the formula (Y20), the formula (Y26), the formula (Y27), and the formula. (Y30), formula (Y31), formula (Y39), formula (Y40), formula (Y42) or formula (Y43), more preferably formula (Y11), formula (Y15), formula. (Y20), formula (Y26), formula (Y27), formula (Y30), formula (Y31), formula (Y39), formula (Y40), formula (Y42) or formula (Y43). ..
The alicyclic hydrocarbon group represented by Y is a spiro ring containing an oxygen atom of the formulas (Y28) to (Y35), formula (Y39), formula (Y40), formula (Y42), formula (Y43) and the like. In some cases, the alkylandyl group between the two oxygen atoms preferably has one or more fluorine atoms. Further, among the alkanediyl groups contained in the ketal structure, it is preferable that the methylene group adjacent to the oxygen atom is not substituted with a fluorine atom.

Examples of the substituent of the methyl group represented by Y include a halogen atom, a hydroxy group, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, a glycidyloxy group, and-(. CH ₂ ) _ja- CO-O-R ^b1 group or-(CH ₂ ) _ja- O-CO-R ^b1 group (in the formula, R ^b1 is an alkyl group having 1 to 16 carbon atoms and 3 to 16 carbon atoms. It represents an alicyclic hydrocarbon group, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group in which they are combined. Ja represents an integer of 0 to 4. The alkyl group and the alicyclic carbonization. The −CH ₂ − contained in the hydrogen group may be replaced by −O−, −S (O) ₂₋ or −CO−, and the alkyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon may be replaced. The hydrogen atom contained in the group may be replaced with a hydroxy group or a fluorine atom.) And the like.
As the substituent of the alicyclic hydrocarbon group represented by Y, an alkyl group having 1 to 16 carbon atoms which may be substituted with a halogen atom, a hydroxy group or a hydroxy group (-CH ₂ contained in the alkyl group). -May be replaced with -O- or -CO-), an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, and 7 to 21 carbon atoms. Aralkyl group, glycidyloxy group,-(CH ₂ ) _ja- CO-O-R ^b1 group ^or- (CH ₂ ) _ja- O-CO-R ^b1 group (in the formula, R ^b1 has ^{1 to} 16 carbon atoms. It represents an alkyl group, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group combining these. Ja represents an integer of 0 to 4. The -CH _2- contained in the alkyl group and the alicyclic hydrocarbon group may be replaced by -O-, -S (O) _2- or -CO-, and the alkyl group, the alicyclic group. The hydrogen atom contained in the hydrocarbon group and the aromatic hydrocarbon group may be replaced with a hydroxy group or a fluorine atom) and the like.

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, an adamantyl group and the like. The alicyclic hydrocarbon group may have a chain hydrocarbon group, and examples thereof include a methylcyclohexyl group and a dimethylcyclohexyl group. The alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms, and more preferably 3 to 10 carbon atoms.
Examples of the aromatic hydrocarbon group include an aryl group such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group and a 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 having 1 to 18 carbon atoms (trill group, xylyl group). Group, cumenyl group, mesityl group, p-methylphenyl group, p-ethylphenyl group, p-tert-butylphenyl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.), and carbon Examples thereof include aromatic hydrocarbon groups (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.) having alicyclic hydrocarbon groups of Nos. 3 to 18. The number of carbon atoms of the aromatic hydrocarbon group is preferably 6 to 14, and more preferably 6 to 10.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, a 2-ethylhexyl group, an octyl group and a nonyl group. Examples include a group, a decyl group, an undecyl group, a dodecyl group and the like. The alkyl group preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and further preferably 1 to 4 carbon atoms.
Examples of the alkyl group substituted with the hydroxy group include hydroxyalkyl groups such as a hydroxymethyl group and a hydroxyethyl group.
Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group and a naphthylethyl group.
Examples of the group in which -CH _2- contained in the alkyl group is replaced with -O-, -S (O) _2- or -CO-, etc. include an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylcarbonyloxy group, or these. Examples include a group that combines.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group. The alkoxy group has preferably 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and further preferably 1 to 4 carbon atoms.
Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, a butoxycarbonyl group and the like. The alkoxycarbonyl group has preferably 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, and even more preferably 2 to 4 carbon atoms.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, a butyryl group and the like. The alkylcarbonyl group preferably has 2-12 carbon atoms, more preferably 2-6 carbon atoms, and even more preferably 2-4 carbon atoms.
Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group and the like. The alkylcarbonyloxy group preferably has 2-12 carbon atoms, more preferably 2-6 carbon atoms, and even more preferably 2-4 carbon atoms.
Examples of the combined group include a group combining an alkoxy group and an alkyl group, a group combining an alkoxy group and an alkoxy group, a group combining an alkoxy group and an alkylcarbonyl group, and an alkoxy group and an alkylcarbonyloxy group. Examples include a group in which the above are combined.
Examples of the group in which the alkoxy group and the alkyl group are combined include an alkoxyalkyl group such as a methoxymethyl group, a methoxyethyl group, an ethoxyethyl group and an ethoxymethyl group. The alkoxyalkyl group has preferably 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, and further preferably 2 to 4 carbon atoms.
Examples of the group in which the alkoxy group and the alkoxy group are combined include an alkoxyalkoxy group such as a methoxymethoxy group, a methoxyethoxy group, an ethoxymethoxy group, and an ethoxyethoxy group. The alkoxyalkoxy group has preferably 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, and further preferably 2 to 4 carbon atoms.
Examples of the group in which the alkoxy group and the alkylcarbonyl group are combined include an alkoxyalkylcarbonyl group such as a methoxyacetyl group, a methoxypropionyl group, an ethoxyacetyl group, and an ethoxypropionyl group. The alkoxyalkylcarbonyl group preferably has 3 to 13 carbon atoms, more preferably 3 to 7 carbon atoms, and even more preferably 3 to 5 carbon atoms.
Examples of the group in which the alkoxy group and the alkylcarbonyloxy group are combined include an alkoxyalkylcarbonyloxy group such as a methoxyacetyloxy group, a methoxypropionyloxy group, an ethoxyacetyloxy group, and an ethoxypropionyloxy group. The alkoxyalkylcarbonyloxy group preferably has 3 to 13 carbon atoms, more preferably 3 to 7 carbon atoms, and even more preferably 3 to 5 carbon atoms.
The groups in which -CH _2- contained in the alicyclic hydrocarbon group is replaced with -O-, -S (O) _2- or -CO-, etc. are represented by the formulas (Y12) to (Y35) and (Y39). ) ~ The groups represented by the formula (Y43) can be mentioned.

Examples of Y include the following.

Y is preferably an alicyclic hydrocarbon group having 3 to 24 carbon atoms which may have a substituent, and more preferably an alicyclic hydrocarbon group having 3 to 20 carbon atoms which may have a substituent. It is a hydrocarbon group, more preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and even more preferably an adamantyl group which may have a substituent. , -CH _2- constituting the alicyclic hydrocarbon group or adamantyl group may be replaced with -CO-, -S (O) _2- or -CO-. Specifically, Y is preferably an adamantyl group, a hydroxyadamantyl group, an oxoadamantyl group, or a group represented by the following.

Examples of the anion in the salt represented by the formula (B1) include anions represented by the formulas (B1-A-1) to (B1-A-59) [hereinafter, "anion (B1-A)" according to the formula number. -1) ”and so on. ] Are preferable, and formulas (B1-A-1) to (B1-A-4), formulas (B1-A-9), formulas (B1-A-10), formulas (B1-A-24) to formulas (B1-A-24) to formulas. (B1-A-33), formulas (B1-A-36) to formulas (B1-A-40), formulas (B1-A-47) to formulas (B1-A-59). Anions are more preferred.

Here, R ^{i2 to} R ⁱ⁷ are, for example, an alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group, independently of each other. R ⁱ⁸ is formed, for example, by an aliphatic hydrocarbon group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 5 to 12 carbon atoms, or a combination thereof. Group, more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group. ^LA4 is a single bond or an alkanediyl group having 1 to 4 carbon atoms.
Q ^b1 and Q ^b2 have the same meanings as above.
Specific examples of the anion in the salt represented by the formula (B1) include the anion described in JP-A-2010-204646.

Examples of the anion in the salt represented by the preferred formula (B1) include anions represented by the formulas (B1a-1) to (B1a-38), respectively.

Among them, equations (B1a-1) to (B1a-3), equations (B1a-7) to (B1a-16), equations (B1a-18), equations (B1a-19), equations (B1a-22). )-Anion represented by any of the formulas (B1a-38) is preferable.

Examples of the Z ⁺ organic cation include an organic onium cation, an organic sulfonium cation, an organic iodonium cation, an organic ammonium cation, a benzothiazolium cation, an organic phosphonium cation, and the like, which are represented by the formula (II-2-A'). The same as the organic cation ZA ⁺ in the structural unit can be mentioned. Of these, organic sulfonium cations and organic iodonium cations are preferable, and aryl sulfonium cations are more preferable.

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 Formulas (B1a-1) to (B1a-3), Formulas (B1a-7) to Formulas (B1a-16), Formulas (B1a-18), Formulas (B1a-). 19), a combination of an anion represented by any of the formulas (B1a-22) to (B1a-38) and a cation (b2-1) or a cation (b2-3) can be mentioned.

Examples of the acid generator (B) preferably include those represented by the formulas (B1-1) to (B1-56), and among them, those containing an arylsulfonium cation are preferable, and the acid generator (B) contains the arylsulfonium cation, and the formula (B1-1). ~ Formula (B1-3), Formula (B1-5) ~ Formula (B1-7), Formula (B1-11) ~ Formula (B1-14), Formula (B1-20) ~ Formula (B1-26), Those represented by the formulas (B1-29) and the formulas (B1-31) to (B1-56) are particularly preferable.

In the resist composition of the present invention, the content of the acid generator is preferably 1 part by mass or more and 45 parts by mass or less, and more preferably 1 part by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the resin (A). More preferably, it is 3 parts by mass or more and 35 parts by mass or less. The resist composition of the present invention may contain one kind of the acid generator (B) alone, or may contain a plurality of kinds.

<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. % Or less. The content of the solvent (E) can be measured by a known analytical means such as liquid chromatography or gas chromatography.
Examples of the solvent (E) include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate; glycol ethers such as propylene glycol monomethyl ether; ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate. Esters; ketones such as acetone, methylisobutylketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; and the like. One type of solvent (E) may be used alone, or two or more types may be used.

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

<Preparation of resist composition>
The resist composition of the present invention comprises a salt (I), a resin (A) and an acid generator (B), and if necessary, a resin other than the resin (A) used, a solvent (E), and a quencher ( It can be prepared by mixing C) and the other component (F). The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can be selected from 10 to 40 ° C., depending on the type of resin or the like and the solubility of the resin or the like in the solvent (E). As the mixing time, an appropriate time can be selected from 0.5 to 24 hours depending on the mixing temperature. The mixing means is not particularly limited, and stirring and mixing or the like can be used.
After mixing each component, it is preferable to filter using a filter having a pore size of about 0.003 to 0.2 μm.

<Manufacturing method of resist pattern>
The method for producing a resist pattern of the present invention is
(1) A step of applying the resist composition of the present invention on a substrate,
(2) A step of drying the applied composition to form a composition layer,
(3) Step of exposing the composition layer,
It includes (4) a step of heating the composition layer after exposure and (5) a step of developing the composition layer after heating.
The resist composition can be applied onto the substrate by a commonly used device such as a spin coater. Examples of the substrate include an inorganic substrate such as a silicon wafer. The substrate may be washed before the resist composition is applied, or an antireflection film or the like may be formed on the substrate.
By drying the composition after coating, the solvent is removed and a composition layer is formed. Drying is performed, for example, by evaporating the solvent using a heating device such as a hot plate (so-called prebaking), or by using a decompression device. The heating temperature is preferably 50 to 200 ° C., and the heating time is preferably 10 to 180 seconds. The pressure at the time of vacuum drying is preferably about 1~1.0 × 10 ⁵ Pa.
The obtained composition layer is usually exposed to an exposure machine. The exposure machine may be an immersion exposure machine. Exposure light sources include those that emit ultraviolet laser light such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), and F ₂ excimer laser (wavelength 157 nm), and solid-state laser light sources (YAG or semiconductor laser). Etc.), wavelength-converted laser light from far-ultraviolet region or vacuum ultraviolet region to emit harmonic laser light, electron beam, super-ultraviolet light (EUV) irradiation, etc. Can be done. In addition, in this specification, irradiation of these radiations may be generically referred to as "exposure". At the time of exposure, the exposure is usually performed through a mask corresponding to the required pattern. When the exposure light source is an electron beam, the exposure may be performed by drawing directly without using a mask.
The exposed composition layer is heat treated (so-called post-exposure bake) to promote the deprotection reaction at the acid unstable group. The heating temperature is usually about 50 to 200 ° C, preferably about 70 to 150 ° C.
The composition layer after heating is usually developed using a developing solution using a developing device. Examples of the developing method include a dip method, a paddle method, a spray method, and a dynamic dispense method. The development temperature is preferably, for example, 5 to 60 ° C., and the development time is preferably, for example, 5 to 300 seconds. A positive resist pattern or a negative resist pattern can be produced by selecting the type of developer as follows.
When a positive resist pattern is produced from the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer may be any alkaline aqueous solution used in this field. For example, an aqueous solution of tetramethylammonium hydroxide or (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as choline) can be mentioned. The alkaline developer may contain a surfactant.
After development, it is preferable to wash the resist pattern with ultrapure water and then remove the substrate and water remaining on the pattern.
When a negative resist pattern is produced from the resist composition of the present invention, a developer containing an organic solvent (hereinafter, may be referred to as "organic developer") is used as the developer.
Examples of the organic solvent contained in the organic developing solution include a ketone solvent such as 2-hexanone and 2-heptanone; a glycol ether ester solvent such as propylene glycol monomethyl ether acetate; an ester solvent such as butyl acetate; and a glycol such as propylene glycol monomethyl ether. Examples thereof include ether solvents; amide solvents such as N and N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole.
The content of the organic solvent in the organic developer is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and further preferably substantially only the organic solvent.
Among them, as the organic developer, a developer containing butyl acetate and / or 2-heptanone is preferable. The total content of butyl acetate and 2-heptanone in the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and substantially butyl acetate and / or 2 -It is even more preferable that it is only heptanone.
The organic developer may contain a surfactant. Further, the organic developer may contain a small amount of water.
At the time of development, the development may be stopped by substituting with a solvent of a type different from that of the organic developer.
It is preferable to wash the developed resist pattern with a rinse solution. The rinsing solution is not particularly limited as long as it does not dissolve the resist pattern, and a solution containing a general organic solvent can be used, and an alcohol solvent or an ester solvent is preferable.
After cleaning, it is preferable to remove the rinse liquid remaining on the substrate and the pattern.

<Use>
The resist composition of the present invention includes a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure, or a resist composition for EUV exposure, particularly electrons. It is suitable as a resist composition for linear (EB) exposure or a resist composition for EUV exposure, and is useful for fine processing of semiconductors.

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

Example 1: Synthesis of salt represented by formula (I-1)
A mixture of 5.00 parts of the compound represented by the formula (I-1-a), 20 parts of chloroform, 5.13 parts of the compound represented by the formula (I-1-b) and 3.40 parts of trifluoromethanesulfonic acid. Then, the mixture was stirred at 23 ° C. for 30 minutes and then cooled to 5 ° C. To the obtained mixture, 4.76 parts of trifluoroacetic anhydride was added dropwise over 15 minutes, and the mixture was further stirred at 23 ° C. for 8 hours. To the obtained mixture, 40 parts of chloroform, 11.47 parts of triethylamine and 22.95 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to obtain an organic layer. 50 parts of a 5% aqueous oxalic acid solution was added to the obtained organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to obtain an organic layer. 50 parts of ion-exchanged water was added to the obtained organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to obtain an organic layer. This washing operation was performed 5 times. After concentrating the obtained organic layer, 30 parts of t-butyl methyl ether was added to the obtained residual, and the mixture was stirred at 23 ° C. for 30 minutes and then filtered to represent the formula (I-1). 1.21 parts of salt was obtained.
MASS (ESI (+) Spectrum): 409.1 [M + H] ⁺

Example 2: Synthesis of salt represented by formula (I-4)
5.40 parts of the compound represented by the formula (I-4-a), 20 parts of chloroform, 5.13 parts of the compound represented by the formula (I-1-b) and 3.40 parts of trifluoromethanesulfonic acid are mixed. Then, the mixture was stirred at 23 ° C. for 30 minutes and then cooled to 5 ° C. To the obtained mixture, 4.76 parts of trifluoroacetic anhydride was added dropwise over 15 minutes, and the mixture was further stirred at 23 ° C. for 8 hours. To the obtained mixture, 40 parts of chloroform, 11.47 parts of triethylamine and 22.95 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to obtain an organic layer. 50 parts of a 5% aqueous oxalic acid solution was added to the obtained organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to obtain an organic layer. 50 parts of ion-exchanged water was added to the obtained organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to obtain an organic layer. This washing operation was performed 5 times. After concentrating the obtained organic layer, 30 parts of t-butyl methyl ether was added to the obtained residual, and the mixture was stirred at 23 ° C. for 30 minutes and then filtered to be represented by the formula (I-4). 0.92 parts of salt was obtained.
MASS (ESI (+) Spectrum): 425.1 [M + H] ⁺

Example 3: Synthesis of salt represented by formula (I-9)
5.05 parts of the compound represented by the formula (I-9-a), 20 parts of chloroform, 5.13 parts of the compound represented by the formula (I-1-b) and 3.40 parts of trifluoromethanesulfonic acid are mixed. Then, the mixture was stirred at 23 ° C. for 30 minutes and then cooled to 5 ° C. To the obtained mixture, 4.76 parts of trifluoroacetic anhydride was added dropwise over 15 minutes, and the mixture was further stirred at 23 ° C. for 8 hours. To the obtained mixture, 40 parts of chloroform, 11.47 parts of triethylamine and 22.95 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes and separated to obtain an organic layer. 50 parts of a 5% aqueous oxalic acid solution was added to the obtained organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to obtain an organic layer. 50 parts of ion-exchanged water was added to the obtained organic layer, and the mixture was stirred at 23 ° C. for 30 minutes and separated to obtain an organic layer. This washing operation was performed 5 times. After concentrating the obtained organic layer, 30 parts of t-butyl methyl ether was added to the obtained residual, and the mixture was stirred at 23 ° C. for 30 minutes and then filtered to represent the formula (I-9). 1.01 part of salt was obtained.
MASS (ESI (+) Spectrum): 411.1 [M + H] ⁺

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

Synthesis Example 1 [Synthesis of resin A1]
As the monomer, a monomer (a1-4-2), a monomer (a1-1-3) and a monomer (a1-2-6) are used, and their molar ratio [monomer (a1-4-2): monomer (a1-1-1). -3): Monomer (a1-2-6)] is mixed so that the ratio is 38:24:38, and the monomer mixture is further multiplied by 1.5 by mass with respect to the total mass of all the monomers. Methyl isobutyl ketone was mixed. Azobisisobutyronitrile as an initiator was added to the obtained mixture so as to be 7 mol% based on the total number of moles of all the monomers, and this was heated at 85 ° C. for about 5 hours to carry out polymerization. It was. Then, a p-toluenesulfonic acid aqueous solution was added to the polymerization reaction solution, and the mixture was stirred for 6 hours and then separated. The resulting organic layer, to precipitate a resin poured into a large amount of n- heptane by filtration and recovered, yield 78 resin A1 (copolymer) is the weight average molecular weight of about 5.3 × 10 ³ Obtained in%. This resin A1 has the following structural units.

Synthesis Example 2 [Synthesis of resin A2]
As the monomer, a monomer (a1-4-2) and a monomer (a1-2-6) are used, and the molar ratio [monomer (a1-4-2): monomer (a1-2-6)] is 38:62. Methyl isobutyl ketone was further mixed with this monomer mixture in an amount of 1.5% by mass based on the total mass of all the monomers. Azobisisobutyronitrile as an initiator was added to the obtained mixture so as to be 7 mol% based on the total number of moles of all the monomers, and this was heated at 85 ° C. for about 5 hours to carry out polymerization. It was. Then, a p-toluenesulfonic acid aqueous solution was added to the polymerization reaction solution, and the mixture was stirred for 6 hours and then separated. The resulting organic layer, to precipitate a resin poured into a large amount of n- heptane by filtration and recovered, the resin weight average molecular weight of about 5.4 × 10 ³ A2 (copolymer) to yield 89 Obtained in%. This resin A2 has the following structural units.

<Preparation of resist composition>
As shown in Table 1, each of the following components was mixed, and the obtained mixture was filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

<Resin>
A1: Resin A1
<Acid generator (B)>
B1-43: Salt represented by the formula (B1-43) (synthesized according to an example of JP-A-2016-47815)
<Salt (I)>
I-1: Salt represented by formula (I-1) I-4: Salt represented by formula (I-4) I-9: Salt represented by formula (I-9) <Quencher (C) )>
IX-1
IX-2
C1: Synthesized by the method described in JP2011-39502.
<Solvent>
Propylene glycol monomethyl ether acetate 400 parts Propylene glycol monomethyl ether 150 parts γ-butyrolactone 5 parts

(Evaluation of electron beam exposure of resist composition)
A 6 inch silicon wafer was treated on a direct hot plate with hexamethyldisilazane at 90 ° C. for 60 seconds. The resist composition was spin-coated on this silicon wafer so that the film thickness of the composition layer was 0.04 μm. Then, on a direct hot plate, a composition layer was formed by prebaking at the temperature shown in the “PB” column of Table 1 for 60 seconds. A contact hole pattern (hole pitch 40 nm / hole) is used on the composition layer formed on the wafer by using an electron beam drawing machine [“ELS-F125 125keV” manufactured by Elionix Inc.] and the exposure amount is changed stepwise. (Diameter 17 nm) was directly drawn.
After exposure, post-exposure baking is performed on a hot plate at the temperature shown in the “PEB” column of Table 1 for 60 seconds, and further paddle development is performed for 60 seconds with a 2.38 mass% tetramethylammonium hydroxide aqueous solution. , A resist pattern was obtained.

In the resist pattern obtained after development, the exposure amount at which the formed hole diameter was 17 nm was defined as the effective sensitivity.

<CD uniformity (CDU) evaluation>
In the effective sensitivity, the hole diameter of the pattern formed with a hole diameter of 17 nm was measured 24 times for each hole, and the average value was taken as the average hole diameter of one hole. The standard deviation was determined by measuring the average hole diameter of a pattern formed with a hole diameter of 17 nm at 400 points on the same wafer as a population.
The results are shown in Table 2. The numbers in the table indicate the standard deviation (nm).

Compared with the comparative compositions 1 and 2, the standard deviation of the compositions 1 to 7 was small, and the CD uniformity (CDU) evaluation was good.

The resist composition containing the salt (I) of the present invention is suitable for microfabrication of semiconductors and is extremely useful in industry because a resist pattern having good CD uniformity (CDU) can be obtained.

Claims (8)

A salt represented by the formula (I).
[In formula (I),
R ¹ represents a halogen atom, an alkyl fluoride group having 1 to 6 carbon atoms, or a hydrocarbon group having 1 to 18 carbon atoms, and −CH ₂ − contained in the hydrocarbon group is −O− or −CO−. It may be replaced with.
R ² and R ³ independently represent a halogen atom, an alkyl fluoride group having 1 to 6 carbon atoms, or a hydrocarbon group having 1 to 18 carbon atoms, and −CH ₂ − contained in the hydrocarbon group is It may be replaced by —O— or −CO−, or R ² and R ³ together to form a single bond or an alkanedyl bridge with 1 to 6 carbon atoms with the carbon atoms to which they are bonded. at best, _-CH 2 contained in the alkanediyl bridge - is, -O -, - S -, - CO -, - SO- or -SO ₂ - may be replaced with.
m1 represents an integer of 0 to 4, when m1 is 2 or more, plural R ¹ may be the same or different from each other.
m2 represents any integer from 0 to 5, and when m2 is 2 or more, a plurality of R ^2s may be the same or different from each other.
m3 represents an integer of 0 to 5, when m3 is 2 or more, plural R ³ may be the same or different from each other.
L ¹ represents an alkanediyl group having 1 to 6 carbon atoms. ] A quencher containing the salt according to claim 1. A resist composition containing the citric acid according to claim 2, a resin containing a structural unit having an acid unstable group, and an acid generator. A claim in which a resin containing a structural unit having an acid unstable group contains at least one selected from the group consisting of a structural unit represented by the formula (a1-1) and a structural unit represented by the formula (a1-2). Item 3. The resist composition according to item 3.
[In the formula (a1-1) and the formula (a1-2),
L ^a1 and L ^a2 independently represent -O- or * -O- (CH ₂ ) _k1 -CO-O-, k1 represents an integer of 1 to 7, and * represents -CO-. Represents the binding site with.
R ^a4 and R ^a5 independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group combining these groups.
m1 represents any integer from 0 to 14.
n1 represents any integer from 0 to 10.
n1'represents an integer of 0 to 3. ] The resist composition according to claim 4, wherein the resin containing a structural unit having an acid unstable group contains a structural unit represented by the formula (a2-A).
[In formula (a2-A),
R ^a50 represents an alkyl group having 1 to 6 carbon atoms which may have a hydrogen atom, a halogen atom or a halogen atom.
^Ra51 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, and 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 binding site with a 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 independently represent -O-, ^-CO -O- or -O-CO-, respectively.
nb represents 0 or 1.
mb represents any integer from 0 to 4. When mb is any integer of 2 or more, the plurality of Ra ^51s may be the same as or different from each other. ] The resist composition according to any one of claims 3 to 5, wherein the acid generator contains a salt represented by the formula (B1).
[In equation (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 an alicyclic hydrocarbon group having 3 to 24 carbon atoms which may have a methyl group which may have a substituent or a substituent, and is contained in the alicyclic hydrocarbon group. CH _2- may be replaced with −O−, −S (O) ₂₋ or −CO−.
Z ⁺ represents an organic cation. ] The resist composition according to any one of claims 3 to 6, further comprising a salt that generates an acid having a weaker acidity than the acid generated from the acid generator. (1) A step of applying the resist composition according to any one of claims 3 to 7 onto a substrate.
(2) A step of drying the applied composition to form a composition layer,
(3) Step of exposing the composition layer,
(4) A step of heating the composition layer after exposure, and (5) A step of developing the composition layer after heating,
A method for producing a resist pattern including.