JP2020063242A - Salt, acid generator, resist composition, and method of producing resist pattern - Google Patents

Abstract

To provide a compound capable of producing an excellent CD-uniformity (CDU) resist pattern, a resin, and a resist composition containing the resin.SOLUTION: Provided are the salt, the acid generator represented by formula (I), and the resist composition containing thereof. In the formula, Qand Qrepresent a fluorine atom or a perfluoroalkyl group respectively, Rand Rrepresent a hydrogen atom, a fluorine atom or a perfluoroalkyl group respectively, z represent any integer of 0-6, Xand Xrepresent each independently -CO-O-, -O-CO-, -O-CO-O- or -O-, Lrepresents a hydrocarbon group which may have a single bond or a substituent group, Arepresents a lactone ring which may have a substituent group, Lrepresents a single bond or an alkanediyl group, Rrepresents a fluorinated hydrocarbon group, and Zrepresents an organic cation.SELECTED DRAWING: None

Description

  The present invention relates to a salt for an acid generator used for fine processing of semiconductors, an acid generator containing the salt, a resist composition and a method for producing a resist pattern.

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

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

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

Patent Document 4 describes a salt represented by the following formula, and a resist composition containing the salt as an acid generator.

Patent Document 5 describes a salt represented by the following formula, and a resist composition containing the salt as an acid generator.

JP, 2009-191054, A JP, 2011-046694, A JP, 2011-126869, A JP, 2017-019997, A JP2012-226325A

  The present invention provides a salt which forms a resist pattern having better CD uniformity (CDU) than the resist pattern formed by the above resist composition.

The present invention includes the following inventions.
[1] A salt represented by the formula (I).
[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
R ¹ and R ² each independently represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
z represents an integer of 0 to 6, and when z is 2 or more, a plurality of R ¹ and R ² may be the same or different from each other.
X ¹ and X ² each independently represent * -CO-O-, * -O-CO-, * -O-CO-O- or * -O-, and * represents C (R ¹ ) ( R ² ) or C (Q ¹ ) (Q ² ), or a binding site with A ¹ or L ² .
L ¹ represents a single bond or a hydrocarbon group having 1 to 28 carbon atoms which may have a substituent, and —CH ₂ — contained in the hydrocarbon group is —O—, —S—, —SO. _It may be replaced by _2- or -CO-.
A ¹ represents a lactone ring having 3 to 36 carbon atoms which may have a substituent.
L ² represents a single bond or an alkanediyl group having 1 to 6 carbon atoms.
R ³ represents a fluorinated hydrocarbon group having 1 to 18 carbon atoms.
Z ⁺ represents an organic cation. ]
[2] The salt according to [1], wherein A ¹ is a norbornane lactone ring.
[3] The salt according to [1] or [2], wherein L ² is a single bond.
[4] L ¹ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, or a group formed by combining an alkanediyl group having 1 to 4 carbon atoms and an adamantanediyl group (--CH ₂ contained in the alkanediyl group. -May be replaced by -O- or -CO-) or a group formed by combining an alkanediyl group having 1 to 4 carbon atoms and a phenylene group which may have a fluorine atom (the alkanediyl group). The —CH ₂ — contained in is optionally replaced with —O— or —CO—), [1] to [3].
[5] The salt according to any one of [1] to [4], wherein R ³ is a fluorinated alkyl group having 1 to 8 carbon atoms or a group represented by formula (R3-1).
[In the formula (R3-1),
L ³ represents a single bond or an alkanediyl group having 1 to 6 carbon atoms.
m3 represents an integer of 1 to 5.
R ⁴ represents a halogen atom or an alkyl group having 1 to 6 carbon atoms, and —CH ₂ — contained in the alkyl group may be replaced with —O— or —CO—.
m4 represents any integer of 0 to 4, and when m4 is 2 or more, a plurality of R ⁴ may be the same as or different from each other.
* Represents a binding site with X ² . ]
[6] An acid generator containing the salt according to any one of [1] to [5].
[7] A resist composition containing the acid generator according to [6] and a resin having an acid labile group.
[8] The resin having an acid labile group contains at least one selected from the group consisting of a structural unit represented by formula (a1-1) and a structural unit represented by formula (a1-2). ] The described resist composition.
[In Formula (a1-1) and Formula (a1-2),
L ^a1 and L ^a2 each independently represent —O— or * —O— (CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, and * represents —CO—. Represents a binding site with.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group combining these.
m1 represents any integer of 0-14.
n1 represents any integer of 0-10.
n1 ′ represents an integer of 0 to 3. ]
[9] The resist composition according to [7] or [8], further containing a salt that generates an acid having a weaker acidity than the acid generated from the acid generator.
[10] A step of applying the resist composition according to any one of [1] [7] to [9] onto a substrate,
(2) a step of drying the composition after coating to form a composition layer,
(3) exposing the composition layer
A method for producing a resist pattern, comprising: (4) heating the composition layer after exposure, and (5) 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).

In the present specification, the “(meth) acrylic monomer” includes a monomer having a structure of “CH ₂ ═CH—CO—” and a monomer having a structure of “CH ₂ ═C (CH ₃ ) —CO—”. It means at least one selected from the group consisting of Similarly, “(meth) acrylate” and “(meth) acrylic acid” mean “at least one selected from the group consisting of acrylate and methacrylate” and “at least one selected from the group consisting of acrylic acid and methacrylic acid”, respectively. Means. If _{"CH 2 = C (CH 3)} -CO- " or "CH ₂ = CH-CO-" structural unit having a are illustrated, structural units having both groups are exemplified similarly I shall. Further, in the groups described in the present specification, any of those having both a linear structure and a branched structure may be used. The “combined group” means a group in which two or more kinds of the exemplified groups are bonded, and the valence of these groups may be appropriately changed depending on the bonding form. When stereoisomers are present, all stereoisomers are included.
In the present specification, the “solid content of the resist composition” means the total of components excluding the solvent (E) described below from the total amount of the resist composition.

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

The perfluoroalkyl group of Q ¹ , Q ² , R ¹ and R ² includes a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group and a perfluorotert-butyl group. , Perfluoropentyl group, perfluorohexyl group and the like.
Q ¹ and Q ² are each independently preferably a trifluoromethyl group or a fluorine atom, more preferably a fluorine atom.
R ¹ and R ² are each independently preferably a hydrogen atom or a fluorine atom.
It is preferable that z is 0 or 1.

X ¹ is, * - CO-O- or * -O-CO - (* is ^{C (R 1) (R 2} ) or ^C (Q 1) (representing the binding site to ^{Q 2).)} It is Is preferred, and * -CO-O- is more preferred.

Examples of the divalent hydrocarbon group represented by L ¹ include an alkanediyl group, a monocyclic or polycyclic divalent alicyclic hydrocarbon group, and a divalent aromatic hydrocarbon group. A group obtained by combining two or more of the above groups (for example, a divalent hydrocarbon group formed from an alicyclic hydrocarbon group and an alkanediyl group) may be used.
Examples of the alkanediyl group include methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane- 1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl Groups, straight chain such as 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 -Like alkanediyl group; and 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 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., branched alkane A diyl group may be mentioned.
Examples of the monocyclic or polycyclic divalent alicyclic hydrocarbon group include cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclooctane A monocyclic divalent alicyclic hydrocarbon group which is a cycloalkanediyl group such as -1,5-diyl group; and norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane- Examples thereof include polycyclic divalent alicyclic hydrocarbon groups such as 1,5-diyl group and adamantane-2,6-diyl group.
Examples of the divalent aromatic hydrocarbon group include aromatic hydrocarbon groups such as phenylene group, naphthylene group, anthrylene group, biphenylene group, and arylene group such as phenanthrylene group.
The group in which two or more kinds are combined represents a group in which an alicyclic hydrocarbon group and an alkanediyl group are combined, or a group in which an aromatic hydrocarbon group and an alkanediyl group are combined, and for example, a -2 valent group Alicyclic hydrocarbon group-alkanediyl group-, -alkanediyl group-divalent alicyclic hydrocarbon group-alkanediyl group-, -alkanediyl group-divalent alicyclic hydrocarbon group-,- Divalent aromatic hydrocarbon group-alkanediyl group-, -alkanediyl group-2 divalent aromatic hydrocarbon group-alkanediyl group-, -alkanediyl group-2 divalent aromatic hydrocarbon group-, and the like. To be
—CH ₂ — contained in the divalent hydrocarbon group having ¹ to 28 carbon atoms of L ¹ may be replaced with —O—, —S—, —SO ₂ — or —CO—.
When —CH ₂ — contained in the hydrocarbon group having ¹ to 28 carbon atoms represented by L ¹ is replaced with —O—, —S—, —SO ₂ — or —CO—, the number of carbon atoms before replacement is shown. Is the number of carbon atoms in the hydrocarbon group.

The substituent which L ¹ may have is a hydroxy group, a carboxy group, a halogen atom, a cyano group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkoxy group having 2 to 13 carbon atoms. Examples thereof include a carbonyl group, an alkylcarbonyl group having 2 to 13 carbon atoms, an alkylcarbonyloxy group having 2 to 13 carbon atoms, and a group combining these.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, octyl group, nonyl group, decyl group and undecyl group. Group, dodecyl group and the like.
Examples of the alkoxy group having 1 to 12 carbon atoms include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, undecyloxy group. Group, dodecyloxy group and the like.
The alkoxycarbonyl group having 2 to 13 carbon atoms, the alkylcarbonyl group having 2 to 13 carbon atoms and the alkylcarbonyloxy group having 2 to 13 carbon atoms are groups in which a carbonyl group or a carbonyloxy group is bonded to the above-mentioned alkyl group or alkoxy group. Represents Examples of the alkoxycarbonyl group having 2 to 13 carbon atoms include methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group and the like, and examples of the alkylcarbonyl group having 2 to 13 carbon atoms include acetyl group, propionyl group and butyryl group. Examples of the alkylcarbonyloxy group having 2 to 13 carbon atoms include an acetyloxy group, a propionyloxy group and a butyryloxy group.

  The substituent is preferably an alkyl group having 1 to 6 carbon atoms, a hydroxy group or a halogen atom, more preferably an alkyl group having 1 to 4 carbon atoms or a halogen atom, and a methyl group or a fluorine atom. Is more preferable.

L ¹ represents a single bond, an alkanediyl group having 1 to 4 carbon atoms (provided that —CH ₂ — contained in the alkanediyl group may be replaced with —O— or —CO—), and carbon number. A group formed by combining an alkanediyl group having 1 to 4 and an alicyclic hydrocarbon group having 3 to 18 carbon atoms (provided that -CH _2- contained in the alkanediyl group is -O- or -CO-. may be replaced, -CH ₂ contained in the alicyclic hydrocarbon group - is, -O -, - S -, - SO 2 -. or -CO- may be replaced by) or 1 carbon atoms Group consisting of an alkanediyl group of 4 to 4 and an aromatic hydrocarbon group of 6 to 18 carbon atoms which may have a substituent (provided that —CH ₂ — contained in the alkanediyl group is —O -Or -CO- may be substituted). , A group formed by combining an alkanediyl group having 1 to 4 carbon atoms, an alkanediyl group having 1 to 4 carbon atoms and an alicyclic hydrocarbon group having 3 to 12 carbon atoms (however, included in the alkanediyl group- CH ₂ — may be replaced with —O— or —CO—) or a group formed by combining an alkanediyl group having 1 to 4 carbon atoms and a phenylene group which may have a substituent (however, -CH ₂ contained in the alkanediyl group -. is more preferably a the may be replaced by -O- or -CO-), a single bond, alkanediyl group having 1 to 4 carbon atoms, carbon atoms A group formed by combining an alkanediyl group of 1 to 4 and an adamantanediyl group (however, —CH ₂ — contained in the alkanediyl group may be replaced with —O— or —CO—) or carbon. Number 1-4 alkane Yl group and a fluorine atom comprising a combination of a well phenylene group having a group (however, -CH ₂ contained in the alkanediyl group - may be replaced by -O- or -CO-.) Is more preferable.
Even more preferably, L ¹ is a single bond.

The lactone ring having 3 to 36 carbon atoms of A ¹ represents a ring in which —CO ₂ —CH ₂ — contained in the alicyclic hydrocarbon ring having 3 to 38 carbon atoms is replaced with —CO—O—, and for example, , And the rings represented by the following.
The ring represented by the following is more preferable as A ¹ .
As A ¹ , a norbornane lactone ring represented by the following is more preferable.

The substituent which A ¹ may have is a hydroxy group, a carboxy group, a halogen atom, a cyano group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkoxy group having 2 to 13 carbon atoms. Examples thereof include a carbonyl group, an alkylcarbonyl group having 2 to 13 carbon atoms, an alkylcarbonyloxy group having 2 to 13 carbon atoms, and a group combining these.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkyl group having 1 to 12 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, octyl group, nonyl group, decyl group and undecyl group. Group, dodecyl group and the like.
Examples of the alkoxy group having 1 to 12 carbon atoms include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, undecyloxy group. Group, dodecyloxy group and the like.
The alkoxycarbonyl group having 2 to 13 carbon atoms, the alkylcarbonyl group having 2 to 13 carbon atoms and the alkylcarbonyloxy group having 2 to 13 carbon atoms are groups in which a carbonyl group or a carbonyloxy group is bonded to the above-mentioned alkyl group or alkoxy group. Represents Examples of the alkoxycarbonyl group having 2 to 13 carbon atoms include methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group and the like, and examples of the alkylcarbonyl group having 2 to 13 carbon atoms include acetyl group, propionyl group and butyryl group. Examples of the alkylcarbonyloxy group having 2 to 13 carbon atoms include an acetyloxy group, a propionyloxy group and a butyryloxy group.

The substituent which A ¹ may have is preferably an alkyl group having 1 to 6 carbon atoms, a hydroxy group, a hydroxyalkyl group, a carboxy group, a cyano group or a halogen atom, and an alkyl group having 1 to 4 carbon atoms. , A hydroxy group, a carboxy group, a cyano group or a halogen atom is more preferable, and a hydroxy group, a cyano group or a halogen atom is further preferable.

Examples of the alkanediyl group having 1 to 6 carbon atoms of L ² include methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane- A linear alkanediyl group such as a 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- A branched alkanediyl group such as a 1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, a 2-methylbutane-1,4-diyl group;
Examples thereof include cycloalkanediyl groups such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group and cyclooctane-1,5-diyl group.
L ² is preferably a single bond or an alkanediyl group having 1 to 3 carbon atoms, and more preferably a single bond.

X ² is preferably * -CO-O- or * -O-CO- (* represents a binding site with A ¹ or L ² ), and more preferably * -CO-O-. preferable.

Examples of the fluorinated hydrocarbon group having 1 to 18 carbon atoms represented by R ³ include an aliphatic hydrocarbon group (a chain hydrocarbon group such as an alkyl group, an alkenyl group and an alkynyl group and an alicyclic hydrocarbon group), Examples thereof include a group in which at least one of hydrogen atoms contained in an aromatic hydrocarbon group and a group obtained by combining these is replaced with a fluorine atom.
Examples of the alkyl group include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, octyl group and nonyl group. The alkyl group has preferably 1 to 9 carbon atoms, and more preferably 1 to 4 carbon atoms.
Examples of the alkenyl group include an ethenyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a tert-butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octynyl group, an isooctynyl group and a nonenyl group.
Examples of the alkynyl group include an ethynyl group, a propynyl group, an isopropynyl group, a butynyl group, an isobutynyl group, a tert-butynyl group, a pentynyl group, a hexynyl group, an octynyl group and a nonynyl group.
The alicyclic hydrocarbon group may be monocyclic, polycyclic or spiro ring, and may be saturated or unsaturated. As the alicyclic hydrocarbon group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, a cyclododecyl group, or another monocyclic cycloalkyl group, a norbornyl group, or an adamantyl group. And polycyclic cycloalkyl groups such as groups.
Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, naphthyl group, anthryl group, biphenyl group, phenanthryl group, and fluorenyl group, and phenyl group, naphthyl group and anthryl group are preferable, and phenyl group and naphthyl group are More preferably, a phenyl group is even more preferable.

The combined group is
A group in which an alicyclic hydrocarbon group and a chain hydrocarbon group such as an alkyl group, an alkenyl group and / or an alkynyl group are combined, an aromatic hydrocarbon group and a chain formula such as an alkyl group, an alkenyl group and / or an alkynyl group It represents a group combining a hydrocarbon group and a group combining an alicyclic hydrocarbon group and an aromatic hydrocarbon group. In the combined group, two or more kinds of the alicyclic hydrocarbon group, chain hydrocarbon group (alkyl group, alkenyl group, alkynyl group) and aromatic hydrocarbon group may be combined.
As a combined group,
Alicyclic hydrocarbon group such as adamantylmethyl group and cyclohexylmethyl group-chain type hydrocarbon group- *,
Chain type hydrocarbon group such as methyladamantyl group-alicyclic hydrocarbon group- *,
Chain type hydrocarbon group such as tolyl group, xylyl group, cyclohexylphenyl group-aromatic hydrocarbon group- *, alicyclic hydrocarbon group-aromatic hydrocarbon group- *,
Chain type hydrocarbon group such as methylcyclohexylmethyl group-alicyclic hydrocarbon group-chain type hydrocarbon group- *,
Aromatic hydrocarbon group such as benzyl group-chain hydrocarbon group- *,
Chain type hydrocarbon group such as tolylmethyl group-Aromatic hydrocarbon group-Chain type hydrocarbon group- *
Etc. Here, * represents a bonding position with X ² .

The fluorinated hydrocarbon group having 1 to 18 carbon atoms represented by R ^3, is preferably a group represented by the fluorinated alkyl group or the formula 1 to 8 carbon atoms (R3-1).
[In the formula (R3-1),
L ³ represents a single bond or an alkanediyl group having 1 to 6 carbon atoms.
m3 represents an integer of 1 to 5.
R ⁴ represents a halogen atom or an alkyl group having 1 to 6 carbon atoms, and —CH ₂ — contained in the alkyl group may be replaced with —O— or —CO—.
m4 represents any integer of 0 to 4, and when m4 is 2 or more, a plurality of R ⁴ may be the same as or different from each other. ]

Examples of the fluorinated alkyl group having 1 to 8 carbon atoms include trifluoromethyl group, difluoromethyl group, perfluoroethyl group, 2,2,2-trifluoroethyl group, 1,1,2,2-tetrafluoroethyl group. Group, perfluoropropyl group, 3,3,3-trifluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, perfluorobutyl group, 4,4,4-trifluorobutyl group, 3,3 , 4,4,4-Pentafluorobutyl group, 2,2,3,3,4,4,4-heptafluorobutyl group, 1,1,2,2,3,3,4,4-octafluorobutyl group Group, perfluoropentyl group, 4,4,5,5,5-pentafluoropentyl group, 3,3,4,4,5,5,5-heptafluoropentyl group, 2,2,3,3,4, 4,5,5,5-Nona Ruolopentyl group, perfluorohexyl group, 5,5,6,6,6-pentafluorohexyl group, 4,4,5,5,6,6,6-heptafluorohexyl group, 3,3,4,4,5 , 5,6,6,6-nonafluorohexyl group, 2,2,3,3,4,4,5,5,6,6,6-dodecafluorohexyl group, perfluoroheptyl group and perfluorooctyl group Can be mentioned.
Among _{them, * -. (CH 2)} m5 -Rf1 (m5 , the .Rf1 representing an integer of 0 to 2, representing * is a perfluoroalkyl group having 1 to 4 carbon atoms, bond with ^{X 2} A group represented by (1) represents a moiety.

Examples of the alkanediyl group having 1 to 6 carbon atoms of L ³ include methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane- A linear alkanediyl group such as a 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- A branched alkanediyl group such as a 1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, a 2-methylbutane-1,4-diyl group;
Examples thereof include cycloalkanediyl groups such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group and cyclooctane-1,5-diyl group.
L ³ is preferably a single bond or a methylene group, and more preferably a methylene group.

Examples of the alkyl group having 1 to 6 carbon atoms of R ⁴ 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 and a hexyl group. The carbon number of the alkyl group is preferably 1 to 4.
Examples of the halogen atom of R ⁴ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
m4 is preferably an integer of 0 to 3, and more preferably an integer of 0 to 2.
m3 is preferably an integer of 2 or more.

Examples of the anion in the salt (I) include anions represented by the following formulas (Ia-1) to (Ia-20). Among them, anions represented by formulas (Ia-1) to (Ia-6) are preferable, and anions represented by formulas (Ia-1) to (Ia-4) and formula (Ia-6) are more preferable. preferable.

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

In formula (b2-1) to formula (b2-4),
R ^{b4 to} R ^b6 each independently represent a chain hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms, The hydrogen atom contained in the chain hydrocarbon group is a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The hydrogen atom which may be substituted and is 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 is —O—, —S— or It may be replaced with -CO-.
R ^b7 and R ^b8 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0-5.
When m2 is 2 or more, a plurality of R ^b7 may be the same or different, and when n2 is 2 or more, a plurality of R ^b8 may be the same or different.
R ^b9 and R ^b10 each independently represent a chain hydrocarbon group having 1 to 36 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms.
R ^b9 and R ^b10 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, and —CH ₂ — contained in the ring is —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 included in the chain hydrocarbon group. The hydrogen atom may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group may be an alkoxy group having 1 to 12 carbon atoms or 1 to 12 carbon atoms. It may be substituted with 12 alkylcarbonyloxy groups.
R ^b11 and R ^b12 may be bonded to each other to form a ring including —CH—CO— to which they are bonded, and —CH ₂ — contained in the ring is —O—, —S. -Or-CO- may be substituted.
R ^{b13 to} R ^b18 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms.
L ^b31 represents a sulfur atom or an oxygen atom.
o2, p2, s2, and t2 each independently represent 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, the plurality of R ^b13 are the same or different, when p2 is 2 or more, the plurality of R ^b14 are the same or different, and when q2 is 2 or more, the plurality of R ^b15 are the same or different. , When r2 is 2 or more, the plurality of R ^b16 are the same or different, when s2 is 2 or more, the plurality of R ^b17 are the same or different, and when t2 is 2 or more, the plurality of R ^b18 are the 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 such as 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 group represented by R ^{b9 to} R ^b12 preferably has 1 to 12 carbon atoms.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon group may be a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group or a cyclohexyl group. Examples thereof include cycloalkyl groups such as heptyl group, cyclooctyl group and cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups.
In particular, the alicyclic hydrocarbon group of R ^{b9 to} R ^b12 preferably has 3 to 18 carbon atoms, and more preferably 4 to 12 carbon atoms.

  Examples of the alicyclic hydrocarbon group having a hydrogen atom 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-isopropyladamantan-2-yl group, methylnorbornyl group, isobornyl group and the like. In the alicyclic hydrocarbon group in which a hydrogen atom is replaced with an aliphatic hydrocarbon group, the total carbon number of the alicyclic hydrocarbon group and the aliphatic hydrocarbon group is preferably 20 or less.

Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, biphenyl group, naphthyl group and phenanthryl group. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group, and an aromatic hydrocarbon group having a chain hydrocarbon group having 1 to 18 carbon atoms (tolyl group, xylyl group). Group, cumenyl group, mesityl group, p-ethylphenyl group, p-tert-butylphenyl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.) and alicyclic ring having 3 to 18 carbon atoms. Examples thereof include aromatic hydrocarbon groups having a formula hydrocarbon group (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.). When the aromatic hydrocarbon group has a chain hydrocarbon group or an alicyclic hydrocarbon group, a chain hydrocarbon group having 1 to 18 carbon atoms and an alicyclic hydrocarbon group having 3 to 18 carbon atoms Is preferred.
A p-methoxyphenyl group etc. are mentioned as an aromatic hydrocarbon group by which the hydrogen atom was substituted by the alkoxy group.
Examples of the chain hydrocarbon group in which a hydrogen atom is replaced by an aromatic hydrocarbon group include aralkyl groups such as benzyl group, phenethyl group, phenylpropyl group, trityl group, naphthylmethyl group and naphthylethyl group.

Examples of the alkoxy group include 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 and a butyryl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, a propylcarbonyloxy group, an isopropylcarbonyloxy group, a butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, a pentylcarbonyloxy group. , A hexylcarbonyloxy group, an octylcarbonyloxy group and a 2-ethylhexylcarbonyloxy group.

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

The ring formed by R ^b9 and R ^{b10 taken} together may be any of a monocyclic ring, a polycyclic ring, an aromatic ring, a non-aromatic ring, a saturated ring and 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. Examples thereof include thiolane-1-ium ring (tetrahydrothiophenium ring), thian-1-ium ring, and 1,4-oxathian-4-ium ring.
The ring formed by R ^b11 and R ^{b12 taken} together may be any of a monocyclic ring, a polycyclic ring, an aromatic ring, a non-aromatic ring, a saturated ring and 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. Examples thereof include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

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

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

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

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

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

  The salt (I) is a combination of the above-mentioned anion and the above-mentioned organic cation, and these can be arbitrarily combined. The salt (I) is preferably a combination of an anion represented by any one of formulas (Ia-1) to (Ia-6) and a cation (b2-1) or a cation (b2-3). To be

Examples of the salt (I) include the salts shown in Table 1. In the table below, each symbol represents a symbol attached to the above-described structure representing anion or cation. For example, the salt (I-1) means a salt composed of an anion represented by the formula (Ia-1) and a cation represented by the formula (b2-c-1) and represents the salts shown below.

  Among them, the salt (I) includes the salt (I-1) to the salt (I-6), the salt (I-15) to the salt (I-20), the salt (I-29) to the salt (I-34), Salt (I-43) to salt (I-48), salt (I-57) to salt (I-62), salt (I-71) to salt (I-76), salt (I-85) to salt It is preferably (I-90).

<Method for producing salt (I)>
In the salt (I), X ¹ is * -CO-O- (* represents a binding site with C (R ¹ ) (R ² ) or C (Q ¹ ) (Q ² )). (Salt represented by formula (I1)) is, for example, obtained by reacting the salt represented by formula (I1-a) with carbonyldiimidazole in a solvent, and then further represented by formula (I1-b). It can be produced by reacting with the compound.
(In the formula, all symbols have the same meanings as described above.)
Examples of the solvent in this reaction include chloroform and acetonitrile.
The reaction temperature is generally 5 ° C to 80 ° C, and the reaction time is generally 0.5 hr to 24 hr.

Examples of the salt represented by the formula (I1-a) include salts represented by the following, and are produced by the methods described in JP2008-127367A and JP2011-046694A. You can
In the compound represented by the formula (I1-b), X ² is * -X ^2b -O- (X ^2b represents a single bond, a carbonyl group or -O-CO-**. * Represents L ² A compound (a compound represented by the formula (I1-b1)) is a compound represented by the formula (I1-c1). It can be produced by reacting a compound represented by formula (I1-d1) with a compound represented by formula (I1-d1) after reacting the compound with carbonyldiimidazole in a solvent.
(In the formula, all symbols have the same meanings as described above. X ^2b represents a single bond, a carbonyl group, or —O—CO— *. * Represents a bonding site with an oxygen atom.)
Examples of the solvent in this reaction include chloroform and acetonitrile.
Examples of the compound represented by the formula (I1-c1) include compounds represented by the following formulas, which can be easily obtained from the market.

Examples of the compound represented by the formula (I1-d1) include compounds represented by the following formula, which can be easily obtained from the market.
The compound represented by formula (I1-b1) is obtained by reacting the compound represented by formula (I1-c1) with the compound represented by formula (I1-d2) in a solvent in the presence of a base. Can also be manufactured by.
(In the formula, all symbols have the same meanings as described above, and X represents a halogen atom.)
Examples of the solvent in this reaction include dimethylformamide, tetrahydrofuran, chloroform, acetonitrile and the like.
Examples of the base in this reaction include potassium carbonate, potassium iodide, triethylamine, pyridine and the like.
The reaction temperature is generally 5 ° C to 80 ° C, and the reaction time is generally 0.5 hr to 24 hr.

Examples of the compound represented by the formula (I1-d2) include compounds represented by the following formula, and they can be easily obtained from the market.

In the compound represented by the formula (I1-b), X ² is a compound (formula (I1-b3)) in which * ² is —O—CO— (* represents a binding site with L ² ). Compound) can also be produced, for example, by reacting the compound represented by formula (I1-c1) with the compound represented by formula (I1-d3) in the presence of a base in a solvent.
(In the formula, all symbols have the same meanings as described above.)
Examples of the solvent in this reaction include dimethylformamide, tetrahydrofuran, chloroform, acetonitrile and the like.
Examples of the base in this reaction include triethylamine, pyridine, dimethylaminopyridine and the like.
The reaction temperature is generally 5 ° C to 80 ° C, and the reaction time is generally 0.5 hr to 24 hr.

Examples of the compound represented by the formula (I1-d3) include compounds represented by the following formula, which can be easily obtained from the market.

In the salt (I), X ¹ is * -O-CO- (* represents a binding site with C (R ¹ ) (R ² ) or C (Q ¹ ) (Q ² )). (Salt represented by formula (I2)) is, for example, obtained by reacting a compound represented by formula (I2-b) with carbonyldiimidazole in a solvent, and then further expressing by formula (I2-a). It can be produced by reacting with a salt.
(In the formula, all symbols have the same meanings as described above.)
Examples of the solvent in this reaction include chloroform and acetonitrile.
The reaction temperature is generally 5 ° C to 80 ° C, and the reaction time is generally 0.5 hr to 24 hr.

Examples of the salt represented by the formula (I2-a) include salts represented by the following, and the salt can be produced by the method described in JP 2012-193170 A.
Examples of the compound represented by the formula (I2-b) include compounds represented by the following formulas, which can be easily obtained from the market.

In the salt (I), X ¹ is, * - O-CO-O - (* ^{is, C (R 1) (R} 2) or ^C (Q 1) (representing the binding site to ^{Q 2).)} In A salt (a salt represented by the formula (I3)) is obtained by, for example, reacting the salt represented by the formula (I2-a) with carbonyldiimidazole in a solvent, and then further reacting with the formula (I1-b). It can be produced by reacting with a compound represented by
(In the formula, all symbols have the same meanings as described above.)
Examples of the solvent in this reaction include chloroform and acetonitrile.
The reaction temperature is generally 5 ° C to 80 ° C, and the reaction time is generally 0.5 hr to 24 hr.

In the salt (I), X ¹ is a salt (formula: * —O— (* represents a binding site with C (R ¹ ) (R ² ) or C (Q ¹ ) (Q ² )). (Salt represented by (I4)) is, for example, by reacting the salt represented by formula (I2-a) with the compound represented by formula (I1-b) in the presence of a base in a solvent. It can be manufactured.
(In the formula, all symbols have the same meanings as described above.)
Examples of the base in this reaction include potassium hydroxide and the like.
Examples of the solvent in this reaction include chloroform, acetonitrile, tetrahydrofuran, dimethylformamide and the like.
The reaction temperature is generally 5 ° C to 80 ° C, and the reaction time is generally 0.5 hr to 24 hr.

<Acid generator>
The acid generator of the present invention is an acid generator containing salt (I). One type of salt (I) may be contained, or two or more types of salt (I) may be contained.
The acid generator of the present invention may contain, in addition to the salt (I), an acid generator known in the resist field (hereinafter sometimes referred to as “acid generator (B)”). The acid generator (B) may be used alone or in combination of two or more kinds.

  The acid generator (B) may be either nonionic or ionic. As the nonionic acid generator, sulfonate esters (for example, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonate), sulfones (for example, disulfone, Ketosulfone, sulfonyldiazomethane) and the like. Representative examples of the ionic acid generator include onium salts containing an onium cation (for example, diazonium salt, phosphonium salt, sulfonium salt, iodonium salt). Examples of the anion of the onium salt include a sulfonate anion, a sulfonylimide anion, and a sulfonylmethide anion.

  Examples of the acid generator (B) include JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038, JP-A-63-163452, and JP-A-63-163452. JP-A-62-153853, JP-A-63-146029, U.S. Pat. No. 3,779,778, U.S. Pat. No. 3,849,137, German Patent No. 3914407, European Patent 126,712, etc. The compounds capable of generating an acid by the radiation described in 1. can be used. Moreover, you may use the compound manufactured by the well-known method. The acid generator (B) may be used in combination of two or more kinds.

The acid generator (B) is preferably a fluorine-containing acid generator, more preferably a salt represented by the formula (B1) (hereinafter sometimes referred to as “acid generator (B1)”).
[In the formula (B1),
Q ^b1 and Q ^b2 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. The hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Y represents a methyl group which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent and is contained in the alicyclic hydrocarbon group; CH ₂ - is, -O -, - S (O ) 2 - or -CO- may be replaced with.
Z ⁺ represents an organic cation. ]

The perfluoroalkyl group represented by Q ^b1 and Q ^b2 includes a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group and A perfluorohexyl group etc. are mentioned.
Q ^b1 and Q ^b2 are preferably each independently a fluorine atom or a trifluoromethyl group, and more preferably both are a fluorine atom.

Examples of the divalent saturated hydrocarbon group for 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, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group , Straight chain such as 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 An alkanediyl group;
Ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane- A branched alkanediyl group such as a 1,3-diyl group, a 2-methylpropane-1,2-diyl group, a pentane-1,4-diyl group, a 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 and the like. Valent alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbon such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group and adamantane-2,6-diyl group Groups and the like.

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, for example, formula (b1-1) to formula (b1-3). And a group represented by any of the above. 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 a binding site, and * represents a bond with -Y.

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

In the group represented by the formula (b1-1) ~ formula (b1-3), -CH ₂ contained in a saturated hydrocarbon radicals - if is replaced by -O- or -CO-, replacing the previous carbon Let the number be the carbon number 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 by -O- or -CO-.

The group in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ^b1 is replaced by —O— or —CO— is represented by the formula (b1-1) or the formula (b1-3). Are preferred groups.

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

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).
[In the formula (b1-9),
L ^b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b20 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. Good. -CH ₂ contained in the alkylcarbonyloxy group - may be replaced by -O- or -CO-, hydrogen atoms contained in the alkylcarbonyloxy group may be substituted by a hydroxy group.
However, the total carbon number of L ^b19 and L ^b20 is 23 or less.
In formula (b1-10),
L ^b21 represents a single bond or a divalent saturated hydrocarbon group having 1 to ²¹ carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b22 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b23 represents a single bond or a divalent saturated hydrocarbon group having 1 to ²¹ carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. Good. -CH ₂ contained in the alkylcarbonyloxy group - may be replaced by -O- or -CO-, hydrogen atoms contained in the alkylcarbonyloxy group may be substituted by a hydroxy group.
However, the total carbon number of L ^b21 , L ^b22 and L ^b23 is 21 or less.
In formula (b1-11),
L ^b24 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b25 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b26 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. Good. -CH ₂ contained in the alkylcarbonyloxy group - may be replaced by -O- or -CO-, hydrogen atoms contained in the alkylcarbonyloxy group may be substituted by a hydroxy group.
However, L ^b24, the total number of carbon atoms of L ^b25 and L ^b26 is 21 or less.
* And ** represent a binding site, and * represents a binding site with Y. ]

  In addition, in the group represented by the formula (b1-9) to the group represented by the formula (b1-11), when a hydrogen atom contained in the saturated hydrocarbon group is substituted with an alkylcarbonyloxy group, it is replaced. Let the previous carbon number be the carbon number of the saturated hydrocarbon group.

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

Examples of the group represented by the formula (b1-4) include the following.
(* And ** represent a binding site, and * represents a binding site with Y.)

Examples of the group represented by the formula (b1-5) include groups below.
(* And ** represent a binding site, and * represents a binding site with Y.)

Examples of the group represented by the formula (b1-6) include the following.
(* And ** represent a binding site, and * represents a binding site with Y.)

Examples of the group represented by the formula (b1-7) include groups below.
(* And ** represent a binding site, and * represents a binding site with Y.)

Examples of the group represented by the formula (b1-8) include groups below.
(* And ** represent a binding site, and * represents a binding site with Y.)

Examples of the group represented by the formula (b1-2) include the following.
(* And ** represent a binding site, and * represents a binding site with Y.)

Examples of the group represented by the formula (b1-9) include groups below.
(* And ** represent a binding site, and * represents a binding site with Y.)

Examples of the group represented by the formula (b1-10) include groups below.
(* And ** represent a binding site, and * represents a binding site with Y.)

Examples of the group represented by the formula (b1-11) include groups below.
(* And ** represent a binding site, and * represents a binding site with Y.)

Examples of the alicyclic hydrocarbon group represented by Y include groups represented by formula (Y1) to formula (Y11) and formula (Y36) to formula (Y38).
Is -O - - -CH ₂ contained in the alicyclic hydrocarbon group represented by _{Y, - S (O) 2} - or replaced by -CO-, to the number it may be one, even in two or more Good. Examples of such a group include groups represented by formula (Y12) to formula (Y35) and formula (Y39) to formula (Y41).

The alicyclic hydrocarbon group represented by Y is preferably formula (Y1) to formula (Y20), formula (Y26), formula (Y27), formula (Y30), formula (Y31), formula (Y39). To a group represented by any one of formula (Y41), more preferably formula (Y11), formula (Y15), formula (Y16), formula (Y20), formula (Y26), formula (Y27), formula A group represented by formula (Y30), formula (Y31), formula (Y39) or formula (Y40), more preferably formula (Y11), formula (Y15), formula (Y20), formula (Y26), formula It is a group represented by (Y27), formula (Y30), formula (Y31), formula (Y39) or formula (Y40).
When the alicyclic hydrocarbon group represented by Y is a spiro ring having an oxygen atom of the formula (Y28) to the formula (Y35), the formula (Y39), the formula (Y40), or the like, between two oxygen atoms It is preferable that the alkanediyl group of has at least one fluorine atom. Further, of 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.

As the substituent of the methyl group represented by Y, a halogen atom, a hydroxy group, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, a glycidyloxy group,-( ^{_{CH 2) ja -CO-O-}} R b1 group or _{- (CH 2) ja -O-} CO-R b1 group ^{(wherein, R b1} represents an alkyl group having 1 to 16 carbon atoms, 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 these are combined, and —CH ₂ — contained in the alkyl group and the alicyclic hydrocarbon group is —O— , —SO ₂ — or —CO— may be substituted, and the hydrogen atom contained in the alkyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group may be replaced with a hydroxy group or a fluorine atom. Ja may represent an integer of 0 to 4. Etc. The.
As the substituent of the alicyclic hydrocarbon group represented by Y, a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms which may be substituted with a hydroxy group, an alicyclic group having 3 to 16 carbon atoms Hydrocarbon group, alkoxy group having 1 to 12 carbon atoms, aromatic hydrocarbon group having 6 to 18 carbon atoms, aralkyl group having 7 to 21 carbon atoms, alkylcarbonyl group having 2 to 4 carbon atoms, glycidyloxy group,-( ^{_{CH 2) ja -CO-O-}} R b1 group or _{- (CH 2) ja -O-} CO-R b1 group ^{(wherein, R b1} represents an alkyl group having 1 to 16 carbon atoms, 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 these are combined, and —CH ₂ — contained in the alkyl group and the alicyclic hydrocarbon group is —O— , -SO ₂ - may be replaced or -CO-, The hydrogen atom contained in the alkyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group may be replaced by a hydroxy group or a fluorine atom, and ja represents an integer of 0 to 4. ) 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 and an adamantyl group.
Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, naphthyl group, anthryl group, biphenyl group and phenanthryl group. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group, and examples of the aromatic hydrocarbon group having a chain hydrocarbon group include a tolyl group, a xylyl 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 aromatic having alicyclic hydrocarbon group. Examples of the hydrocarbon group include p-cyclohexylphenyl group and p-adamantylphenyl group.
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. Group, decyl group, undecyl group, dodecyl group and the like.
Examples of the alkyl group substituted with a hydroxy group include hydroxyalkyl groups such as hydroxymethyl group and hydroxyethyl group.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group.
Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group and a naphthylethyl group.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group and a butyryl group.

Examples of Y include the following.

Y is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and more preferably an adamantyl group which may have a substituent. is -CO - - -CH ₂ constituting a hydrogen group or an adamantyl group, - S _{(O) 2} - or -CO- may be replaced with. Y is more preferably an adamantyl group, a hydroxyadamantyl group, an oxoadamantyl group or a group represented by the following.

  The anion in the salt represented by the formula (B1) is an anion represented by the formula (B1-A-1) to the formula (B1-A-55) [hereinafter, anion (B1-A depending on the formula number. -1) "and so on. ] Are preferable, Formula (B1-A-1) -Formula (B1-A-4), Formula (B1-A-9), Formula (B1-A-10), Formula (B1-A-24) -Formula (B1-A-33), Formula (B1-A-36) to Formula (B1-A-40), Formula (B1-A-47) to Formula (B1-A-55). Anions are more preferred.

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

Examples of preferable anions in the salt represented by the formula (B1) include anions represented by the formulas (B1a-1) to (B1a-34).

  Especially, Formula (B1a-1) -Formula (B1a-3) and Formula (B1a-7) -Formula (B1a-16), Formula (B1a-18), Formula (B1a-19), Formula (B1a-22). ) To formula (B1a-30) are preferred.

Examples of the organic cation of Z1 ⁺ 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, and the same as the cation Z ⁺ in the salt (I). Can be mentioned.

  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 the formula (B1a-1) to the formula (B1a-3) and the formula (B1a-7) to the formula (B1a-16), the formula (B1a-18), the formula (B1a-). 19) and a combination of the anion represented by any of the formulas (B1a-22) to (B1a-34) and the cation (b2-1) or the cation (b2-3).

As the acid generator (B), those represented by formulas (B1-1) to (B1-48) are preferably exemplified. Among them, those containing an arylsulfonium cation are preferable, and the formula (B1-1) to the formula (B1-3), the formula (B1-5) to the formula (B1-7), the formula (B1-11) to the formula (B1-14). ), The formula (B1-20) to the formula (B1-26), the formula (B1-29), and the formula (B1-31) to the formula (B1-48) are particularly preferable.

When the salt (I) and the acid generator (B) are contained as the acid generator, the ratio of the contents of the salt (I) and the acid generator (B) (mass ratio; salt (I): acid generator ( B)) is usually 1:99 to 99: 1, preferably 2:98 to 98: 2, more preferably 5:95 to 95: 5, and further preferably 10:90 to 90. : 10 and particularly preferably 15:85 to 85:15.
In the resist composition of the present invention, the total content of the acid generators is preferably 1 part by mass or more and 40 parts by mass or less, more preferably 3 parts by mass or more with respect to 100 parts by mass of the resin (A) described below. It is 35 parts by mass or less.

<Resist composition>
The resist composition of the present invention contains an acid generator containing a salt (I) and a resin having an acid labile group (hereinafter sometimes referred to as “resin (A)”). Here, the "acid-labile group" has a leaving group, the leaving group is released by contact with an acid, the structural unit has a hydrophilic group (for example, a hydroxy group or a carboxy group) Means a group that is converted to a unit.
The resist composition of the present invention preferably contains a quencher such as a salt that generates an acid having a weaker acidity than the acid generated from the acid generator (hereinafter sometimes referred to as “quencher (C)”). , A solvent (hereinafter sometimes referred to as “solvent (E)”) is preferably contained.

<Resin (A)>
The resin (A) has a structural unit having an acid labile group (hereinafter sometimes referred to as “structural unit (a1)”). The resin (A) preferably further contains a structural unit other than the structural unit (a1). Examples of the structural unit other than the structural unit (a1) include a structural unit having no acid labile group (hereinafter sometimes referred to as “structural unit (s)”), structural unit (a1) and structural unit (s). A structural unit (for example, a structural unit having a halogen atom described below (hereinafter sometimes referred to as “structural unit (a4)”) and a structural unit having a non-eliminating hydrocarbon group described below (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 labile group (hereinafter sometimes referred to as “monomer (a1)”).
The acid labile group contained in the resin (A) is a group represented by the formula (1) (hereinafter, also referred to as the group (1)) and / or a group represented by the formula (2) (hereinafter, the group (2 ) Is also preferable).
[In Formula (1), R ^a1 , R ^a2, and R ^a3 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a group in which these are combined. That is, 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 each independently represent 0 or 1, and at least one of ma and na represents 1.
* Represents a bond. ]
[In Formula (2), R ^{a1 ′} and R ^{a2 ′} each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^{a3 ′} represents a hydrocarbon group having 1 to 20 carbon atoms. Or R ^{a2 ′} and R ^{a3 ′} are bonded to each other to form a heterocyclic group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded and X, and are included 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 a bond. ]

^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 for 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 cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups (* represents a bond). The alicyclic hydrocarbon group of R ^a1 , R ^a2 and R ^a3 preferably has 3 to 16 carbon atoms.
Examples of the group in which an alkyl group and an alicyclic hydrocarbon group are combined include, for example, methylcyclohexyl group, dimethylcyclohexyl group, methylnorbornyl group, cyclohexylmethyl group, adamantylmethyl group, adamantyldimethyl group, norbornyl group. Examples thereof include an ethyl group.
Preferably, ma is 0 and na is 1.
The following groups are mentioned as -C (R ^a1 ) (R ^a2 ) (R ^a3 ) when R ^a1 and R ^a2 are bonded to each other to form an alicyclic hydrocarbon group. The alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms. * Represents a bond with -O-.

Examples of the hydrocarbon group for R ^{a1 ′} , R ^{a2 ′,} and R ^{a3 ′} include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these.
Examples of the alkyl group and the alicyclic hydrocarbon group include the same groups as those mentioned for R ^a1 , R ^a2 and R ^a3 .
Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, naphthyl group, anthryl group, biphenyl group and phenanthryl group.
Examples of the combined group include a group in which the above-described alkyl group and an alicyclic hydrocarbon group are combined (for example, a cycloalkylalkyl group), an aralkyl group such as a benzyl group, an aromatic hydrocarbon group having an alkyl group (p-methyl group). Phenyl group, p-tert-butylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.), alicyclic hydrocarbon group Examples thereof include aromatic hydrocarbon groups (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.) and aryl-cycloalkyl groups such as phenylcyclohexyl group.
^{Examples of} the heterocyclic group formed by R ^{a2 ′} and R ^{a3 ′} bonded to each other and the carbon atom to which they are bonded and X are the following groups. * Represents a bond.
At least one of R ^{a1 ′} and R ^{a2 ′} is preferably a hydrogen atom.
na ′ is preferably 0.

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

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

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

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

As the structural unit derived from the (meth) acrylic monomer having the group (1), a structural unit represented by the formula (a1-0) (hereinafter, sometimes referred to as the structural unit (a1-0)), a formula ( The structural unit represented by a1-1) (hereinafter sometimes referred to as the structural unit (a1-1)) or the structural unit represented by the formula (a1-2) (hereinafter referred to as the structural unit (a1-2). There are some cases). Preferably, it is at least one structural unit selected from the group consisting of structural unit (a1-1) and structural unit (a1-2). These may be used alone or in combination of two or more.
[In Formula (a1-0), Formula (a1-1), and Formula (a1-2),
L ^a01 , L ^a1 and L ^a2 each independently represent —O— or ^* —O— (CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, and * represents Represents a bond with -CO-.
R ^a01 , R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a02 , R ^a03 and R ^a04 each independently ^represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group combining these.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group formed by combining these.
m1 represents an integer of 0 to 14.
n1 represents any integer of 0-10.
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 atoms or * —O— (CH ₂ ) _k01 —CO—O— (however, k01 is preferably an integer of 1 to 4, more preferably Is 1.), more preferably an oxygen atom.
Examples of the alkyl group in R ^a02 , R ^a03 , R ^a04 , R ^a6, and R ^a7 , the alicyclic hydrocarbon group, and a group in which these groups are combined include the groups listed for R ^a1 , R ^a2, and R ^a3 in the formula (1). And the same groups as.
The alkyl group in R ^a02 , R ^a03 , and R ^a04 preferably has 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group, and further preferably a methyl group.
The alkyl group in R ^a6 and R ^a7 preferably has 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group or an isopropyl group, and further preferably an ethyl group or an isopropyl group.
The carbon number of the alicyclic hydrocarbon group of R ^a02 , R ^a03 and R ^a04 is preferably 5 to 12, and more preferably 5 to 10.
The group in which an alkyl group and an alicyclic hydrocarbon group are combined preferably has a total carbon number of 18 or less in which these alkyl groups and an alicyclic hydrocarbon group are combined.
R ^a02 and R ^a03 are preferably an alkyl group having 1 to 6 carbon atoms, and more preferably a methyl group or an ethyl group.
R ^a04 is preferably an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 5 to 12 carbon atoms, and more preferably a methyl group, 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 still more preferably an ethyl group or an isopropyl group.
m1 is preferably an integer of 0 to 3, and 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.

Examples of the structural unit (a1-0) include structural units represented by any of the formulas (a1-0-1) to (a1-0-12) and R ^a01 in the structural unit (a1-0). Structural units in which the corresponding methyl groups are replaced by hydrogen atoms are mentioned, 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 JP2010-204646A. Among them, the structural unit represented by any of the formulas (a1-1-1) to (a1-1-4) and the methyl group corresponding to R ^a4 in the structural unit (a1-1) were replaced with hydrogen atoms. 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). A structural unit in which a methyl group is replaced with a hydrogen atom can be given, and structural units represented by formula (a1-2-2), formula (a1-2-5) and formula (a1-2-6) are preferable.

When the resin (A) contains the structural unit (a1-0) and / or the structural unit (a1-1) and / or the structural unit (a1-2), the total content of these is the total structure of the resin (A). For units,
Usually, it is 10 to 95 mol%, preferably 15 to 90 mol%, more preferably 20 to 85 mol%, further preferably 25 to 70 mol%, still more preferably 30 to 70 mol%. is there.

Examples of the structural unit having the group (2) in the structural unit (a1) include structural units represented by the formula (a1-4) (hereinafter sometimes referred to as “structural unit (a1-4)”). .
[In the formula (a1-4),
R ^a32 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a33 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl It represents an oxy group or a methacryloyloxy group.
la represents an integer of 0 to 4. When la is 2 or more, plural R ^{a33 s} 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 And form a divalent hydrocarbon group having 2 to 20 carbon atoms with —C—O— to which they are bonded, and —CH ₂ — contained in the hydrocarbon group and the divalent hydrocarbon group is — It may be replaced with 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, 1,1, 2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3,3 4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group, etc. Can be mentioned.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group and a hexyloxy group. Among them, an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is further 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 and an octyl group.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, the following groups (* represents a bonding site) and the like.
Examples of the aromatic hydrocarbon group include aryl groups such as phenyl group, naphthyl group, anthryl group, biphenyl group and phenanthryl group.
Examples of the combined group include a group in which the above-described alkyl group and an alicyclic hydrocarbon group are combined (for example, a cycloalkylalkyl group), an aralkyl group such as a benzyl group, an aromatic hydrocarbon group having an alkyl group (p-methyl group). Phenyl group, p-tert-butylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.), alicyclic hydrocarbon group Examples thereof include aromatic hydrocarbon groups (p-cyclohexylphenyl group, p-adamantylphenyl group, etc.) and aryl-cycloalkyl groups such as phenylcyclohexyl group. In particular, R ^a36 is an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group formed by combining these. Is mentioned.

In formula (a1-4), R ^a32 is preferably a hydrogen atom.
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 having 1 to 12 carbon atoms or an alicyclic hydrocarbon group, 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. The group formed is more preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms or an aralkyl group having 7 to 18 carbon atoms. The alkyl group and alicyclic hydrocarbon group for R ^a36 are preferably unsubstituted. The aromatic hydrocarbon group for R ^a36 is preferably an aromatic ring having an aryloxy group having 6 to 10 carbon atoms.

^{-OC (R a34) (R a35} ) -O-R a36 in 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 structural units derived from a monomer described in JP 2010-204646 A. 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 A unit is mentioned, More preferably, the structural unit respectively represented by Formula (a1-4-1) -Formula (a1-4-5) and Formula (a1-4-10) is mentioned.

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

Examples of the structural unit derived from the (meth) acrylic monomer having the group (2) also include a structural unit represented by the formula (a1-5) (hereinafter sometimes referred to as “structural unit (a1-5)”). To be
In formula (a1-5),
R ^a8 represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
Z ^a1 represents a single bond or _{* - (CH 2) h3 -CO} -L 54 - represents, h3 represents an integer of 1 to 4, * represents a bond to L ^51.
L ^51, L ^52, L ⁵³ and L ⁵⁴ each independently represents -O- or -S-.
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.
Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom 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, a fluoromethyl group and trifluoromethyl. Groups.
In formula (a1-5), R ^a8 is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.
L ⁵¹ is preferably an oxygen atom.
It is preferable that one of L ⁵² and L ⁵³ is —O— and the other is —S—.
s1 is preferably 1.
s1 ′ is preferably an integer of 0-2.
Z ^a1 is preferably a single bond or * —CH ₂ —CO—O—.

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

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

Examples of the structural unit (a1) also include a structural unit represented by the formula (a1-0X) (hereinafter sometimes referred to as structural unit (a1-0X)).
[In the formula (a1-0X),
R ^x1 represents a hydrogen atom or a methyl group.
R ^x2 and R ^x3 each independently represent a saturated hydrocarbon group having 1 to 6 carbon atoms.
Ar ^x1 represents an aromatic hydrocarbon group having 6 to 36 carbon atoms. ]

Examples of the saturated hydrocarbon group for R ^x2 and R ^x3 include an alkyl group, an alicyclic hydrocarbon group, and a group formed by combining these.
Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group.

Examples of the aromatic hydrocarbon group of Ar ^x1 include aryl groups having 6 to 36 carbon atoms such as a phenyl group, a naphthyl group, and an anthryl group.
The aromatic hydrocarbon group preferably has 6 to 24 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably a phenyl group.

Ar ^x1 is preferably an aromatic hydrocarbon group having 6 to 18 carbon atoms, more preferably a phenyl group or a naphthyl group, and further preferably a phenyl group.
R ^x1 , R ^x2, and R ^x3 are each independently preferably a methyl group or an ethyl group, and more preferably a methyl group.

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

When the resin (A) has the structural unit (a1-0X), its content is preferably 5 to 60 mol%, and preferably 5 to 50 mol%, based on all the monomers in the resin (A). It is more preferable that the amount is 10 to 40 mol%.
The resin (A) may contain two or more types of structural units (a1-0X).

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

  When the resin (A) contains the structural unit, the content thereof is preferably 5 to 60 mol%, more preferably 5 to 50 mol%, and further preferably 10 to 40 mol, based on all the structural units of the resin (A). % Is more preferable.

<Structural unit (s)>
As the monomer leading to the structural unit (s), a monomer having no acid labile group known in the resist field can be used.
The structural unit (s) preferably has a hydroxy group or a lactone ring. A structural unit having a hydroxy group and having no acid labile group (hereinafter sometimes referred to as "structural unit (a2)") and / or a lactone ring and having no acid labile group When a resin having a unit (hereinafter sometimes referred to as “structural unit (a3)”) is used in the resist composition of the present invention, the resolution of the resist pattern and 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 KrF excimer laser (248 nm), electron beam or EUV (ultraviolet light) is used as an exposure light source, the structural unit (a2) is used. It is preferable to use the structural unit (a2) having a phenolic hydroxy group. When using an ArF excimer laser (193 nm) or the like, the structural unit (a2) is preferably a structural unit (a2) having an alcoholic hydroxy group, and the structural unit (a2-1) described later is more preferable. preferable. As the structural unit (a2), one type may be used alone, or two or more types may be used.

Examples of the structural unit having a phenolic hydroxy group in the structural unit (a2) include structural units represented by the formula (a2-A) (hereinafter sometimes referred to as “structural unit (a2-A)”).
[In the formula (a2-A),
R ^a50 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a51 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, or acryloyl. It 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 bond 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 each independently represent —O—, ^—CO —O— or —O—CO—.
nb represents 0 or 1.
mb represents the integer in any one of 0-4. When mb is any integer greater than or equal to 2, some R ^<a51> may mutually be same or different. ]

^Examples of the halogen atom for R ^a50 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 R ^a50 include trifluoromethyl group, difluoromethyl group, methyl group, perfluoroethyl group, 2,2,2-trifluoroethyl group, 1 , 1,2,2-Tetrafluoroethyl group, ethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3 , 3,4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group and perfluorohexyl group Groups.
R ^a50 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, still more preferably a hydrogen atom or a methyl group.
^Examples of the alkyl group for R ^a51 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 R ^a51 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 for R ^a51 include an acetyl group, a propionyl group and a butyryl group.
^Examples of the alkylcarbonyloxy group for R ^a51 include an acetyloxy group, a propionyloxy group and a butyryloxy group.
R ^a51 is preferably a methyl group.

^{* -X a51 - (A a52 -X} a52) nb - The, * - 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 -, And the like. Among them, * -CO-O-, * -CO-O- ^Aa52- CO-O- or * -O- ^Aa52- CO-O- is preferable.

Examples of the alkanediyl group include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane- 1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group and 2 -Methylbutane-1,4-diyl group and the like.
A ^a52 is preferably a methylene group or an ethylene group.

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

mb is preferably 0, 1 or 2, more preferably 0 or 1, and particularly preferably 0.
The hydroxy group is preferably bonded to the ortho position or para position of the benzene ring, more preferably to the para position.

As the structural unit (a2-A), the structural unit represented by the formula (a2-2-1) to the formula (a2-2-6), and the formula (a2-2-1) to the formula (a2-2-). ^Examples of the structural unit represented by 6) include a structural unit in which a methyl group corresponding to R ^a50 in the structural unit (a2-A) is replaced with a hydrogen atom. The structural unit (a2-A) is represented by the structural unit represented by the formula (a2-2-1), the structural unit represented by the formula (a2-2-3), and the structural unit (a2-2-6). In the structural unit represented by the formula (a2-2-1), the structural unit represented by the formula (a2-2-3) or the structural unit represented by the formula (a2-2-6), It is preferable that the methyl group corresponding to R ^a50 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% with respect to all structural units, and more preferably 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 contained in the resin (A) by, for example, polymerizing 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 structural units represented by the formula (a2-1) (hereinafter sometimes referred to as “structural unit (a2-1)”).
In formula (a2-1),
L ^a3 represents -O- or ^* -O- (CH ₂ ) _k2- CO-O-,
k2 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 each independently represent a hydrogen atom, a methyl group or a hydroxy group.
o1 represents any integer of 0-10.

In Formula (a2-1), L ^a3 is preferably —O—, —O— (CH ₂ ) _f1 —CO—O— (wherein f1 represents any integer of 1 to 4). , And 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 2010-204646 A. The structural unit represented by any of the formulas (a2-1-1) to (a2-1-6) is preferable, and the structural unit represented by any of the formulas (a2-1-1) to (a2-1-4) is preferable. 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% with respect to the total structural units of the resin (A). %, More preferably 1 to 35 mol%, further preferably 2 to 20 mol%, and still more preferably 2 to 10 mol%.

<Structural unit (a3)>
The lactone ring contained in the structural unit (a3) may be a single ring such as a β-propiolactone ring, a γ-butyrolactone ring, or a δ-valerolactone ring, or a condensed ring of a monocyclic lactone ring and another ring. But it's okay. 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)) is 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). These may be contained alone or in combination of two or more.
[In Formula (a3-1), Formula (a3-2), Formula (a3-3), and Formula (a3-4),
L ^a4 , L ^a5 and L ^a6 are each independently represented by —O— or * —O— (CH ₂ ) _k3— CO—O— (k3 represents 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 * -O- ^La8- O-CO- ^La9- O- is represented.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
* Represents a binding site to 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 which may have a halogen atom, a hydrogen atom or a halogen atom.
X ^a3 is, -CH ₂ - represents an 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 of 0-5.
q1 represents an integer of 0 to 3.
r1 represents an integer of 0 to 3.
w1 represents any integer of 0-8.
When p1, q1, r1 and / or w1 are 2 or more, a plurality of R ^a21 , R ^a22 , R ^a23 and / or R ^a25 may be the same as or different from each other. ]

Examples of the aliphatic hydrocarbon group for R ^a21 , R ^a22 , R ^a23 and R ^a25 include an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group and a tert-butyl group. To be
Examples of the halogen atom for R ^a24 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
^Examples of the alkyl group for R ^a24 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. And an alkyl group are more preferable, and a methyl group or an ethyl group is more preferable.
Examples of the alkyl group having a halogen atom in R ^a24 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group and a perfluoro group. Hexyl group, trichloromethyl group, tribromomethyl group, triiodomethyl group and the like can be mentioned.
^Examples of the alkanediyl group in L ^a8 and L ^a9 include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5. -Diyl group, hexane-1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1, Examples thereof include 4-diyl group and 2-methylbutane-1,4-diyl group.

In formula (a3-1) to formula (a3-3), L ^{a4 to} L ^a6 are each independently, preferably —O— or * —O— (CH ₂ ) _k3— CO—O—, k3. Is a group in which any of 1 to 4 is an integer, more preferably —O— and * —O—CH ₂ —CO—O—, and further preferably an oxygen atom.
R ^{a18 to} R ^a21 are preferably methyl groups.
R ^a22 and R ^a23 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are each independently preferably an integer of 0 to 2, and more preferably 0 or 1.

In formula (a3-4), R ^a24 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and further preferably a hydrogen atom or a methyl group. 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, and more preferably 0 or 1.
Particularly, the formula (a3-4) is preferably the formula (a3-4) ′.
(In the formula, R ^a24 and L ^a7 have the same meanings as described above.)

As the structural unit (a3), 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. Units are mentioned. As the structural unit (a3), formula (a3-1-1), formula (a3-1-2), formula (a3-2-1), formula (a3-2-2), formula (a3-3-). 1), the structural unit represented by any of the formula (a3-3-2) and the formula (a3-4-1) to the formula (a3-4-12), and the structural unit represented by the formula (a3-1). ) To formula (a3-4), a structural unit in which a methyl group corresponding to R ^a18 , R ^a19 , R ^a20 and R ^a24 in the formula (a3-4) is replaced with a hydrogen atom is preferable.

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

<Structural unit (a4)>
Examples of the structural unit (a4) include the following structural units.
[In the formula (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.

The chain hydrocarbon group includes a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a decyl group, a dodecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group and an 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, cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group and the following groups. (* Represents a bond) and other polycyclic alicyclic hydrocarbon groups.
Examples of the group formed by the combination include a group formed by combining one or more alkyl groups or one or more alkanediyl groups and one or more alicyclic hydrocarbon groups, and -alkanediyl group- 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 formula (a4-0), formula (a4-1), formula (a4-2), formula (a4-3) and formula (a4-4). The structural unit represented by one is mentioned.
[In the formula (a4-0),
R ^5a represents a hydrogen atom or a methyl group.
L ^4a represents a single bond or an alkanediyl group having 1 to 4 carbon atoms.
L ^3a represents a C 1-8 perfluoroalkanediyl group or a C 3-12 perfluorocycloalkanediyl group.
R ^6a represents a hydrogen atom or a fluorine atom. ]

The alkanediyl group for L ^4a includes a straight-chain alkanediyl group such as methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, ethane-1,1-diyl group, Examples include branched alkanediyl groups such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group. To be

^Examples of the perfluoroalkanediyl group in L ^3a include 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, perfluoro Tan-2,2-diyl group, perfluoroheptane-3,4-diyl group, perfluoroheptane-4,4-diyl group, perfluorooctane-1,8-diyl group, perfluorooctane-2,2-diyl group, perfluoro Octane-3,3-diyl group, perfluorooctane-4,4-diyl group and the like can be mentioned.
^Examples of the perfluorocycloalkanediyl group in L ^3a include a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, and a perfluoroadamantanediyl group.

L ^4a is preferably a single bond, a methylene group or an ethylene group, and more preferably a single bond or 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.

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

[In the formula (a4-1),
R ^a41 represents a hydrogen atom or a methyl group.
R ^a42 represents a saturated hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is replaced with —O— or —CO—. May be.
A ^a41 represents an ^optionally substituted alkanediyl group having 1 to 6 carbon atoms or a group represented by the formula (a-g1). However, at least one of A ^a41 and R ^a42 has a halogen atom (preferably a fluorine atom) as a substituent.
[In the formula (a-g1),
s represents 0 or 1.
A ^a42 and A ^a44 each independently represent a divalent saturated hydrocarbon group having 1 to 5 carbon atoms which may have a substituent.
A ^a43 represents a divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a single bond or a substituent.
X ^a41 and X ^a42 each independently represent —O—, —CO—, ^—CO —O— or —O—CO—.
However, the total number of carbon atoms of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 7 or less. ]
* Is a bond, and * on the right is a bond with -O-CO- ^Ra42 . ]

^Examples of the saturated hydrocarbon group for R ^a42 include a chain saturated hydrocarbon group, a monocyclic or polycyclic alicyclic saturated hydrocarbon group, and a group formed by combining these.

Examples of the chain saturated hydrocarbon group 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. Is mentioned.
Examples of the monocyclic or polycyclic alicyclic saturated hydrocarbon group include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group and Examples thereof include polycyclic alicyclic saturated hydrocarbon groups such as groups (* represents a bond).
Examples of the group formed by the combination include a group formed by combining one or more alkyl groups or one or more alkanediyl groups and one or more saturated alicyclic hydrocarbon groups, and an -alkanediyl group. Examples include -saturated alicyclic hydrocarbon group, -saturated alicyclic hydrocarbon group-alkyl group, -alkanediyl group-saturated alicyclic hydrocarbon group-alkyl group and the like.

^Examples of the substituent that R ^a42 may have include at least one selected from the group consisting of a halogen atom and a group represented by formula (a-g3). Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.
[In the formula (a-g3),
X ^a43 represents an oxygen atom, a carbonyl group, **-O-CO-, or **-CO-O- (** represents a bond with R ^a42 ).
A ^a45 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
* Represents a bond. ]
However, in R ^a42 -X ^a43 -A ^a45 , when R ^a42 does not have a halogen atom, A ^a45 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms and having at least one halogen atom.

^Examples of the aliphatic hydrocarbon group for A ^a45 include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group, dodecyl group, pentadecyl group, hexadecyl group, heptadecyl group and Alkyl group such as octadecyl group;
Monocyclic alicyclic hydrocarbon groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group; and decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* represents a bond) .) And other polycyclic alicyclic hydrocarbon groups.
Examples of the group formed by the combination include a group formed by combining one or more alkyl groups or one or more alkanediyl groups and one or more alicyclic hydrocarbon groups, and -alkanediyl group- 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 a saturated hydrocarbon group which may have a halogen atom, and more preferably a saturated hydrocarbon group having an alkyl group having a halogen atom and / or a group represented by the formula (a-g3).
When R ^a42 is a saturated hydrocarbon group having a halogen atom, it is preferably a saturated hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, further preferably a carbon number of 1 to 1 A perfluoroalkyl group having 6 carbon atoms, particularly preferably a perfluoroalkyl group having 1 to 3 carbon atoms. Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group and a perfluorooctyl group. Examples of the perfluorocycloalkyl group include a perfluorocyclohexyl group and the like.
When R ^a42 is a saturated hydrocarbon group having a group represented by formula (a-g3), the total carbon number of R ^a42 including the number of carbon atoms contained in the group represented by formula (a-g3). The number is preferably 15 or less, more preferably 12 or less. When the group represented by formula (a-g3) has a substituent, the number thereof is preferably 1.

When R ^a42 is a saturated hydrocarbon group having a group represented by formula (a-g3), R ^a42 is more preferably a group represented by formula (a-g2).
[In the formula (a-g2),
A ^a46 represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
^Xa44 represents **-O-CO- or **-CO-O- (** represents a bond with ^Aa46 ).
A ^a47 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
However, the total number of carbon atoms of A ^a46 , A ^a47 and X ^a44 is 18 or less, and at least one of A ^a46 and A ^a47 has at least one halogen atom.
* Represents a bond with the carbonyl group. ]

1-6 are preferable and, as for carbon number of the saturated hydrocarbon group of ^Aa46 , 1-3 are more preferable.
The aliphatic hydrocarbon group of A ^a47 preferably has 4 to 15 carbon atoms, more preferably 5 to 12 carbon atoms, and A ^a47 is more preferably a cyclohexyl group or an adamantyl group.

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

The alkanediyl group in A ^a41 is a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group. A linear alkanediyl group such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,2-diyl group, 1-methylbutane-1,4-diyl group, Examples thereof include branched alkanediyl groups such as 2-methylbutane-1,4-diyl group.
^Examples of the substituent in the alkanediyl group represented by 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 alkanediyl group and a monocyclic or polycyclic divalent group. Examples thereof include an alicyclic hydrocarbon group, and a group formed by combining an alkanediyl group and a divalent alicyclic hydrocarbon group. Specifically, a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a 1-methylpropane-1,3-diyl group, Examples thereof include 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.
^Examples of the substituent of the 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.

^{Examples of the} group represented by the formula (a-g1) in which X ^a42 is —O—, ^—CO— , ^—CO —O— or —O—CO— include the following groups. In the following examples, * and ** each represent a bond, and ** is a bond with -O-CO- ^Ra42 .

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

As the structural unit represented by formula (a4-1), the structural unit represented by formula (a4-2) is preferable.
[In the formula (a4-2),
R ^f5 represents a hydrogen atom or a methyl group.
L ⁴⁴ represents an alkanediyl group having 1 to 6 carbon atoms, and —CH ₂ — contained in the alkanediyl group may be replaced with —O— or —CO—.
R ^f6 represents a saturated hydrocarbon group having 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. ]

As the alkanediyl group for L ⁴⁴ , the same groups as those exemplified for A ^a41 can be mentioned.
Examples of the saturated hydrocarbon group for R ^f6 include the same groups as those exemplified for R ^a42 .
As the alkanediyl group for 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 formula (a4-1-1) to the formula (a4-1-11). A structural unit in which a methyl group corresponding to R ^f5 in the structural unit (a4-2) is replaced with a hydrogen atom is also included as the structural unit represented by the formula (a4-2).

[In formula (a4-3),
R ^f7 represents a hydrogen atom or a methyl group.
L ⁵ represents an alkanediyl group having 1 to 6 carbon atoms.
A ^f13 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms which may have a fluorine atom.
^Xf12 represents * -O-CO- or * -CO-O- (* represents a bond with ^Af13 ).
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 for L ⁵ include the same groups as those exemplified for the alkanediyl group for A ^a41 .

The divalent saturated hydrocarbon group which may have a fluorine atom in A ^f13 is preferably a divalent chain saturated hydrocarbon group which may have a fluorine atom and a fluorine atom. Is a divalent alicyclic saturated hydrocarbon group, more preferably a perfluoroalkanediyl group.
Examples of the divalent chain hydrocarbon group which may have a fluorine atom include alkanediyl groups such as methylene group, ethylene group, propanediyl group, butanediyl group and pentanediyl group; difluoromethylene group, perfluoroethylene group, perfluoro group. Examples thereof include perfluoroalkanediyl groups such as propanediyl group, perfluorobutanediyl group and perfluoropentanediyl group.
The divalent alicyclic hydrocarbon group which may have a fluorine atom may be either monocyclic or polycyclic. Examples of the monocyclic group include a cyclohexanediyl group and a perfluorocyclohexanediyl group. Examples of the polycyclic group include an adamantanediyl group, a norbornanediyl group and a perfluoroadamantanediyl group.

Examples of the saturated hydrocarbon group of A ^{f14 and} the saturated hydrocarbon group which may have a fluorine atom include the same groups as those exemplified for R ^a42 . Among them, trifluoromethyl group, difluoromethyl group, methyl group, perfluoroethyl group, 2,2,2-trifluoroethyl group, 1,1,2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3,4,4-octafluorobutyl group, butyl group, perfluoropentyl group, Fluorination of 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group, heptyl group, perfluoroheptyl group, octyl group, perfluorooctyl group, etc. Alkyl group, cyclopropylmethyl group, cyclopropyl group, cyclobutylmethyl group, cyclopentyl group, cyclohexyl group, Fluorocyclohexyl group, adamantyl group, adamantylmethyl group, adamantyl dimethyl group, norbornyl group, norbornylmethyl group, perfluoro adamantyl group, a perfluoroalkyl adamantylmethyl group and the like are preferable.

In formula (a4-3), L ⁵ is preferably an ethylene group.
The divalent saturated hydrocarbon group of A ^f13 is preferably a group containing a divalent chain hydrocarbon group having 1 to 6 carbon atoms and a divalent alicyclic hydrocarbon group having 3 to 12 carbon atoms, and having a carbon number of A 2-3 divalent chain hydrocarbon group is more preferred.
The saturated hydrocarbon group for 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 are 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 formula (a4-1′-1) to the formula (a4-1′-11). A structural unit in which a methyl group corresponding to R ^f7 in the structural unit (a4-3) is replaced with a hydrogen atom is also included as the structural unit represented by the formula (a4-3).

The structural unit (a4) also includes a structural unit represented by the formula (a4-4).
[In the formula (a4-4),
R ^f21 represents a hydrogen atom or a methyl group.
A ^f21 _{is, - (CH 2) j1 -} , - (CH 2) j2 -O- (CH 2) j3 - or _{- (CH 2) j4 -CO-} O- (CH 2) j5 - represents a.
j1 to j5 each independently represent an integer of 1 to 6.
R ^f22 represents a C 1-10 saturated hydrocarbon group having a fluorine atom. ]

^Examples of the saturated hydrocarbon group of R ^f22 include the same as the saturated hydrocarbon group represented by R ^a42 . R ^f22 is preferably a ^C 1-10 alkyl group having a fluorine atom or a C 1-10 alicyclic hydrocarbon group having a fluorine atom, more preferably a C 1-10 alkyl group having a fluorine atom. Preferably, a C1-C6 alkyl group having a fluorine atom is more preferable.

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

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

  When the resin (A) has the structural unit (a4), its content is preferably 1 to 20 mol%, more preferably 2 to 15 mol%, based on all the structural units of the resin (A). It is more preferably from 10 to 10 mol%.

<Structural unit (a5)>
Examples of the non-eliminating hydrocarbon group contained in the structural unit (a5) include groups 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 structural units represented by the formula (a5-1).
[In the formula (a5-1),
R ⁵¹ represents a hydrogen atom or a methyl group.
R ⁵² represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms. .
L ⁵⁵ represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced with —O— or —CO—. . ]

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

Examples of the divalent saturated hydrocarbon group for L ⁵⁵ include a divalent chain saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, preferably a divalent chain saturated hydrocarbon group. .
Examples of the divalent chain saturated hydrocarbon group include alkanediyl groups such as methylene group, ethylene group, propanediyl group, butanediyl group and pentanediyl group.
The divalent alicyclic saturated hydrocarbon group may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic saturated hydrocarbon group include cycloalkanediyl groups such as cyclopentanediyl group and cyclohexanediyl group. Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include an adamantanediyl group and a norbornanediyl group.

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

L ^x1 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group.
L ^x2 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, 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, more preferably a methylene group or an ethylene group.
L ^x6 is preferably a single bond or a C 1-8 divalent aliphatic saturated hydrocarbon group, more preferably a methylene group or an ethylene group.
L ^x7 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x8 is preferably a single bond or a divalent 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 ^x1 is preferably a divalent alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms, and more preferably a cyclohexanediyl group or an adamantanediyl group.

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

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

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

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 a structural unit shown below and a structural unit in which a 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 the structural unit (a5), its content is preferably 1 to 30 mol%, more preferably 2 to 20 mol%, based on the total structural units of the resin (A). ˜15 mol% is more preferred.

<Structural unit (II)>
The resin (A) may further contain a structural unit that decomposes upon exposure to generate an acid (hereinafter, may be referred to as “structural unit (II)”). Specific examples of the structural unit (II) include structural units described in JP-A-2016-79235, and a structural unit having a sulfonate group or a carboxylate group and an organic cation in a side chain, or a sulfonio in a 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 its side chain is preferably a structural unit represented by the formula (II-2-A ′).
[In the formula (II-2-A ′),
X ^III3 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced with —O—, —S— or —CO—. Of course, 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 a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
ZA ⁺ represents an organic cation. ]

Examples of the halogen atom represented by R ^III3 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
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.
Examples of the alkanediyl group having 1 to 8 carbon atoms represented by A ^x1 include methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group. , Hexane-1,6-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2, 4-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group, etc. Can be mentioned.
Examples of the perfluoroalkyl group having 1 to 6 carbon atoms which may be substituted with A ^X1 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group and a perfluorotert group. -Butyl group, perfluoropentyl group, perfluorohexyl group and the like.
Examples of the divalent saturated hydrocarbon group having 1 to 18 carbon atoms represented by X ^III3 include a linear or branched alkanediyl group and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group. However, these may be combined.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1. , 6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group , A linear alkanediyl group such as dodecane-1,12-diyl group; butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group , A branched alkanediyl group such as pentane-1,4-diyl group and 2-methylbutane-1,4-diyl group; cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1 , 4-diyl group, Cycloalkanediyl groups such as rooctane-1,5-diyl group; norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane-2,6-diyl group And other divalent polycyclic alicyclic saturated hydrocarbon groups.
Examples of the —CH ₂ — contained in the saturated hydrocarbon group replaced with —O—, —S— or —CO— include divalent groups represented by formula (X1) to formula (X53). Can be mentioned. However, -CH ₂ contained in a saturated hydrocarbon group - is, -O -, - number of carbon atoms before replacing with S- or -CO- is respectively 17 or less. In the following formula, * and ** represent a binding site, and * represents a bond with A ^x1 .

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

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

The structural unit represented by formula (II-2-A ′) is preferably the structural unit represented by formula (II-2-A).
Wherein ^(II-2-A), R III3, X III3 and ZA ⁺ are the same as defined above.
z2A represents an integer of 0 to 6.
R ^III2 and R ^III4 each independently represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and when z is 2 or more, a plurality of R ^III2 and R ^III4 are the same as each other. It may be different or different.
Q ^a and Q ^b each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group. ]
^Examples of the perfluoroalkyl group having 1 to 6 carbon atoms represented by R ^III2 , R ^III4 , Q ^a and Q ^b include the same as the perfluoroalkyl group having 1 to 6 carbon atoms represented by Q ^b1 described above. .

The structural unit represented by formula (II-2-A) is preferably the structural unit represented by formula (II-2-A-1).
[In the formula (II-2-A-1),
R ^III2 , R ^III3 , R ^III4 , Q ^a , Q ^b and ZA ⁺ have the same meanings as described above.
R ^III5 represents a saturated hydrocarbon group having 1 to 12 carbon atoms.
z2A1 represents an integer of 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—. Well, 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 methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, Examples thereof include linear or branched alkyl groups such as heptyl group, octyl group, nonyl group, decyl group, undecyl group and dodecyl group.
Examples of the divalent saturated hydrocarbon group represented by X ^I2 include those similar to the divalent saturated hydrocarbon group represented by X ^III3 .

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.
Wherein (II-2-A-2 ), R III3, R III5 and ZA ⁺ are the same as defined above.
m and n each independently represent 1 or 2. ]

As the structural unit represented by the formula (II-2-A ′), for example, the following structural unit, a 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 a structural unit in which an alkyl group having 1 to 6 carbon atoms (for example, a trifluoromethyl group) which may be possessed and a structural unit described in WO 2012/050015 are described. ZA ⁺ represents an organic cation.

The structural unit having a sulfonio group and an organic anion in its side chain is preferably a structural unit represented by the formula (II-1-1).
[In the 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 a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
A ⁻ represents an organic anion. ]
Examples of the divalent aromatic hydrocarbon group having 6 to 18 carbon atoms represented by R ^II1 include a phenylene group and a naphthylene group.
Examples of the hydrocarbon group represented by R ^II2 and R ^II3 include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these.
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 divalent saturated hydrocarbon groups 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-. Specific examples thereof include the same as the divalent saturated hydrocarbon group having 1 to 18 carbon atoms represented by X ^III3 .

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 a hydrogen atom, a fluorine atom, trifluoromethyl or the like. Examples include structural units.

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

A ^- The sulfonyl imide anions represented by, the following may be mentioned.

Examples of the sulfonylmethide anion include the following.

Examples of the carboxylate anion include the following.

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

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

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

The resin (A) is preferably a resin composed of the structural unit (a1) and the structural unit (s).
The structural unit (a1) is preferably a group consisting of the structural unit (a1-0), the structural unit (a1-1) and the structural unit (a1-2) (preferably the structural unit having a cyclohexyl group and a cyclopentyl group). It is at least one kind selected from the above, and more preferably at least two kinds.
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 represented by the formula (a2-A) or a structural unit represented by the formula (a2-1). 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). It is 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, radical polymerization method) using a monomer that guides these structural units. be able to. The content of each structural unit contained in the resin (A) can be adjusted by the amount of the monomer used for polymerization.
The weight average molecular weight of the resin (A) is preferably 2,000 or more (more preferably 2,500 or more, further preferably 3,000 or more), 50,000 or less (more preferably 30,000 or less, further preferably) Is 15,000 or less). In this specification, the weight average molecular weight is a value determined by gel permeation chromatography under the conditions described in the examples.

<Resin other than resin (A)>
The resist composition of the present invention may use a resin other than the resin (A) in combination.
Examples of the resin other than the resin (A) include a resin containing the structural unit (a4) or the structural unit (a5) (hereinafter sometimes referred to as resin (X)) and the like.

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

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, radical polymerization method) using a monomer that induces these structural units. can do. The content of each structural unit contained in the resin (X) can be adjusted by the amount of the monomer used for polymerization.
The weight average molecular weight of the resin (X) is preferably 6,000 or more (more preferably 7,000 or more) and 80,000 or less (more preferably 60,000 or less). The means for measuring the weight average molecular weight of the resin (X) is the same as that for the resin (A).
When the resist composition contains the resin (X), the content thereof is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, relative to 100 parts by mass of the resin (A). , More preferably 1 to 40 parts by mass, particularly preferably 1 to 30 parts by mass, 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 the resin other than the resin (A) is included, the total content of the resin (A) and the resin other than the resin (A) is 80% by mass or more and 99% by mass or more based on the solid content of the resist composition. The amount is preferably the following, and more preferably 90% by mass or more and 99% by mass or less. In the present specification, the “solid content of the resist composition” means the total of components excluding the solvent (E) described below from the total amount of the resist composition. The solid content of the resist composition and the resin content relative thereto can be measured by a known analysis means such as liquid chromatography or gas chromatography.

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

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

  As the amine, 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N-dimethylaniline, diphenylamine, hexylamine, Heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, tri Heptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, Ludicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyl Didecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, 2,2'-methylenebisaniline, imidazole, 4- Tylimidazole, pyridine, 4-methylpyridine, 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,2-di (2-pyridyl) ethene, 1,2- Di (4-pyridyl) ethene, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyloxy) ethane, di (2-pyridyl) ketone, 4,4′-dipyridyl sulfide, 4 , 4'-dipyridyl disulfide, 2,2'-dipyridyl amine, 2,2'-dipicolyl amine, bipyridine and the like, preferably aromatic amines such as diisopropylaniline, and more preferably 2,6- Diisopropylaniline may be mentioned.

  Examples of 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 generates an acid having a weaker acidity than the acid generated from the acid generator (B) is represented by an 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 in which the acid dissociation constant of the acid generated from the salt is usually -3 <pKa, and preferably -1 < It is a salt of pKa <7, more preferably a salt of 0 <pKa <5.
As the salt that generates an acid having a weaker acidity than the acid generated from the acid generator (B), 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 inner salt (D)".), And JP2012-229206A, JP2012-6908A, JP2012-72109A, and JP2011-39502A. The salts described in the official gazette and JP 2011-191745 A may be mentioned. The salt that generates an acid having a weaker acidity than the acid generated from the acid generator (B) is preferably a weak acid intramolecular salt (D).

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

<Other ingredients>
The resist composition of the present invention may contain a component (hereinafter sometimes referred to as “other component (F)”) other than the above components, if necessary. The other component (F) is not particularly limited, and additives known in the resist field, such as a sensitizer, a dissolution inhibitor, a surfactant, a stabilizer, and a dye can be used.

<Preparation of resist composition>
The resist composition of the present invention comprises a salt (I), a resin (A), and, if necessary, an acid generator (B), a resin other than the resin (A), a solvent (E), a quencher (C). And other components (F) can be mixed to prepare. 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, the solubility of the resin or the like in the solvent (E), or the like. 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 can be used.
After mixing the components, it is preferable to filter using a filter having a pore size of about 0.003 to 0.2 μm.

<Method of manufacturing 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 onto a substrate,
(2) a step of drying the composition after coating to form a composition layer,
(3) 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.

  Application of the resist composition onto the substrate can be carried out by a commonly used apparatus such as a spin coater. Examples of the substrate include inorganic substrates such as silicon wafers. The substrate may be washed before applying the resist composition, or an antireflection film or the like may be formed on the substrate.

The composition is dried to remove the solvent and form a composition layer. Drying is performed, for example, by evaporating the solvent using a heating device such as a hot plate (so-called prebaking) or 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 during drying under reduced pressure is preferably about 1 to 1.0 × 10 ⁵ Pa.

The obtained composition layer is usually exposed using an exposure device. The exposure machine may be an immersion exposure machine. As the exposure light source, one that emits laser light in the ultraviolet region such as a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), an F ₂ excimer laser (wavelength 157 nm), a solid-state laser light source (YAG or semiconductor laser) Etc.) that emits harmonic laser light in the far-ultraviolet region or vacuum-ultraviolet region by wavelength-converting the laser light from, etc., electron beams, or those that emit ultra-ultraviolet light (EUV), etc. You can In the present specification, the irradiation of these radiations may be collectively 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, it may be exposed by direct drawing without using a mask.

  The composition layer after exposure is subjected to a heat treatment (so-called post-exposure bake) in order to accelerate the deprotection reaction at the acid labile group. The heating temperature is usually about 50 to 200 ° C, preferably about 70 to 150 ° C.

  The composition layer after heating is usually developed using a developing device using a developing solution. 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 5 to 60 ° C., and the development time is preferably 5 to 300 seconds. A positive resist pattern or a negative resist pattern can be manufactured 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 of various alkaline aqueous solutions used in this field. Examples thereof include an aqueous solution of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline). The alkaline developer may contain a surfactant.
After development, it is preferable to wash the resist pattern with ultrapure water, and then remove the water remaining on the substrate and the pattern.

When a negative resist pattern is produced from the resist composition of the present invention, a developer containing an organic solvent (hereinafter sometimes referred to as "organic developer") is used as the developer.
Examples of the organic solvent contained in the organic developer include ketone solvents such as 2-hexanone and 2-heptanone; glycol ether ester solvents such as propylene glycol monomethyl ether acetate; ester solvents such as butyl acetate; glycols such as propylene glycol monomethyl ether. Examples include ether solvents; amide solvents such as N, N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole.
The content of the organic solvent in the organic developer is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and further preferably substantially only the organic solvent.
Among them, the organic developer is preferably a developer containing butyl acetate and / or 2-heptanone. 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 More preferably only heptanone.
A surfactant may be contained in the organic developer. 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 different type from the organic developer.

It is preferable to wash the resist pattern after development with a rinse liquid. The rinse liquid is not particularly limited as long as it does not dissolve the resist pattern, and a solution containing a general organic solvent can be used, 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 is a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure or a resist composition for EUV exposure, especially an electron. It is suitable as a resist composition for line (EB) exposure or a resist composition for EUV exposure and is useful for fine processing of semiconductors.

The present invention will be described more specifically with reference to examples. In the examples, “%” and “part” indicating the content or the amount used are based on mass unless otherwise specified.
The weight average molecular weight is a value determined by gel permeation chromatography. The analysis conditions of gel permeation chromatography are as follows.
Column: TSKgel Multipore HXL-M x 3 + guard column (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ℃
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)
The structure of the compound was confirmed by measuring a molecular ion peak using mass spectrometry (LC: Agilent model 1100, MASS: Agilent LC / MSD model). 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)
3 parts of the compound represented by the formula (I-1-a), 10 parts of dimethylformamide, 1.05 parts of potassium carbonate and 1.26 parts of potassium iodide were mixed and stirred at 23 ° C. for 30 minutes, and then the formula ( 8.49 parts of the compound represented by I-1-b) was added, and then the mixture was stirred at 23 ° C. for 18 hours. 50 parts of tert-butyl methyl ether and 30 parts of ion-exchanged water were added to the obtained reaction mixture, and the mixture was stirred at 23 ° C. for 30 minutes, then, separated, and the organic layer was taken out. 30 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. This water washing operation was repeated 3 times. The obtained organic layer was concentrated, and the concentrated mixture was subjected to a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: n-heptane / ethyl acetate = 3/1). By fractionating, 5.19 parts of the compound represented by the formula (I-1-c) were obtained.
After mixing 2.5 parts of the salt represented by formula (I-1-e) and 30 parts of acetonitrile and stirring the mixture at 23 ° C. for 30 minutes, the compound represented by formula (I-1-f) 1.17. Parts were added, the temperature was raised to 50 ° C., and the mixture was stirred at 50 ° C. for 2 hours. 3.04 parts of the compound represented by the formula (I-1-c) was added to the obtained reaction mixture, and the mixture was stirred at 50 ° C. for 10 hr. The obtained reaction mixture was cooled to 23 ° C., 50 parts of chloroform and 25 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes, then, separated, and the organic layer was taken out. 25 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, and then liquid-separated to take out the organic layer. This water washing operation was repeated 5 times. To the obtained organic layer, 25 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. 75 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. The obtained organic layer was concentrated, 2 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue, and the mixture was stirred at 23 ° C. for 30 minutes, then, the supernatant liquid was removed and concentrated to obtain the compound of the formula ( 4.18 parts of salt represented by I-1) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 601.0

Example 2: Synthesis of salt represented by formula (I-2)
4 parts of the compound represented by the formula (I-1-a), 10 parts of dimethylformamide, 1.39 parts of potassium carbonate and 1.68 parts of potassium iodide were mixed and stirred at 23 ° C. for 30 minutes, and then the formula ( 5.27 parts of the compound represented by I-2-b) was added, and then the mixture was stirred at 23 ° C. for 18 hours. 50 parts of tert-butyl methyl ether and 30 parts of ion-exchanged water were added to the obtained reaction mixture, and the mixture was stirred at 23 ° C. for 30 minutes, then, separated, and the organic layer was taken out. 30 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. This water washing operation was repeated 3 times. The obtained organic layer was concentrated, and the concentrated mixture was subjected to a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: n-heptane / ethyl acetate = 3/1). By fractionating, 4.66 parts of the compound represented by the formula (I-2-c) were obtained.
After mixing 2.5 parts of the salt represented by formula (I-1-e) and 30 parts of acetonitrile and stirring the mixture at 23 ° C. for 30 minutes, the compound represented by formula (I-1-f) 1.17. Parts were added, the temperature was raised to 50 ° C., and the mixture was stirred at 50 ° C. for 2 hours. 2.59 parts of the compound represented by the formula (I-2-c) was added to the obtained reaction mixture, and the mixture was stirred at 50 ° C. for 10 hr. The obtained reaction mixture was cooled to 23 ° C., 50 parts of chloroform and 25 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes, then, separated, and the organic layer was taken out. 25 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, and then liquid-separated to take out the organic layer. This water washing operation was repeated 5 times. To the obtained organic layer, 25 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. 75 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. The obtained organic layer was concentrated, 2 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue, and the mixture was stirred at 23 ° C. for 30 minutes, then, the supernatant liquid was removed and concentrated to obtain the compound of the formula ( 1.99 parts of the salt represented by I-2) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 535.0

Example 3: Synthesis of salt represented by formula (I-3)
3 parts of the compound represented by the formula (I-1-a), 10 parts of dimethylformamide, 1.05 parts of potassium carbonate and 1.26 parts of potassium iodide were mixed and stirred at 23 ° C. for 30 minutes, and then the formula ( 5.97 parts of the compound represented by I-3-b) were added, and then the mixture was stirred at 23 ° C. for 18 hours. 50 parts of tert-butyl methyl ether and 30 parts of ion-exchanged water were added to the obtained reaction mixture, and the mixture was stirred at 23 ° C. for 30 minutes, then, separated, and the organic layer was taken out. 30 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. This water washing operation was repeated 3 times. The obtained organic layer was concentrated, and the concentrated mixture was subjected to a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: n-heptane / ethyl acetate = 3/1). By fractionating, 3.96 parts of the compound represented by the formula (I-3-c) were obtained.
After mixing 2.5 parts of the salt represented by formula (I-1-e) and 30 parts of acetonitrile and stirring the mixture at 23 ° C. for 30 minutes, the compound represented by formula (I-1-f) 1.17. Parts were added, the temperature was raised to 50 ° C., and the mixture was stirred at 50 ° C. for 2 hours. 2.60 parts of the compound represented by the formula (I-3-c) was added to the obtained reaction mixture, and the mixture was stirred at 50 ° C for 10 hr. The obtained reaction mixture was cooled to 23 ° C., 50 parts of chloroform and 25 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes, then, separated, and the organic layer was taken out. 25 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, and then liquid-separated to take out the organic layer. This water washing operation was repeated 5 times. To the obtained organic layer, 25 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. 75 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. The obtained organic layer was concentrated, 2 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue, and the mixture was stirred at 23 ° C. for 30 minutes, then, the supernatant liquid was removed and concentrated to obtain the compound of the formula ( 3.01 parts of the salt represented by I-3) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 537.0

Example 4: Synthesis of salt represented by formula (I-4)
4 parts of the compound represented by the formula (I-1-a), 10 parts of dimethylformamide, 1.39 parts of potassium carbonate and 1.68 parts of potassium iodide were mixed and stirred at 23 ° C. for 30 minutes, and then the formula ( 4.54 parts of the compound represented by I-4-b) was added, and then the mixture was stirred at 23 ° C. for 18 hours. 50 parts of tert-butyl methyl ether and 30 parts of ion-exchanged water were added to the obtained reaction mixture, and the mixture was stirred at 23 ° C. for 30 minutes, then, separated, and the organic layer was taken out. 30 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. This water washing operation was repeated 3 times. The obtained organic layer was concentrated, and the concentrated mixture was subjected to a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: n-heptane / ethyl acetate = 3/1). By fractionating, 4.24 parts of the compound represented by the formula (I-2-c) was obtained.
After mixing 2.5 parts of the salt represented by formula (I-1-e) and 30 parts of acetonitrile and stirring the mixture at 23 ° C. for 30 minutes, the compound represented by formula (I-1-f) 1.17. Parts were added, the temperature was raised to 50 ° C., and the mixture was stirred at 50 ° C. for 2 hours. 2.34 parts of the compound represented by the formula (I-4-c) was added to the obtained reaction mixture, and the mixture was stirred at 50 ° C for 10 hr. The obtained reaction mixture was cooled to 23 ° C., 50 parts of chloroform and 25 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes, then, separated, and the organic layer was taken out. 25 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, and then liquid-separated to take out the organic layer. This water washing operation was repeated 5 times. To the obtained organic layer, 25 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. 75 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. The obtained organic layer was concentrated, 2 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue, and the mixture was stirred at 23 ° C. for 30 minutes, then, the supernatant liquid was removed and concentrated to obtain the compound of the formula ( 3.12 parts of salt represented by I-4) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 499.0

Example 5: Synthesis of salt represented by formula (I-6)
4 parts of the compound represented by the formula (I-1-a), 10 parts of dimethylformamide, 1.39 parts of potassium carbonate and 1.68 parts of potassium iodide were mixed and stirred at 23 ° C. for 30 minutes, and then the formula ( 4.18 parts of the compound represented by I-6-b) was added, and then the mixture was stirred at 23 ° C. for 18 hours. 50 parts of tert-butyl methyl ether and 30 parts of ion-exchanged water were added to the obtained reaction mixture, and the mixture was stirred at 23 ° C. for 30 minutes, then, separated, and the organic layer was taken out. 30 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. This water washing operation was repeated 3 times. The obtained organic layer was concentrated, and the concentrated mixture was subjected to a column (silica gel 60N (spherical, neutral) 100-210 μm; manufactured by Kanto Chemical Co., Inc., developing solvent: n-heptane / ethyl acetate = 3/1). By fractionating, 4.32 parts of the compound represented by the formula (I-6-c) were obtained.
After mixing 2.5 parts of the salt represented by formula (I-1-e) and 30 parts of acetonitrile and stirring the mixture at 23 ° C. for 30 minutes, the compound represented by formula (I-1-f) 1.17. Parts were added, the temperature was raised to 50 ° C., and the mixture was stirred at 50 ° C. for 2 hours. 2.22 parts of the compound represented by the formula (I-6-c) was added to the obtained reaction mixture, and the mixture was stirred at 50 ° C. for 10 hr. The obtained reaction mixture was cooled to 23 ° C., 50 parts of chloroform and 25 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes, then, separated, and the organic layer was taken out. 25 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, and then liquid-separated to take out the organic layer. This water washing operation was repeated 5 times. To the obtained organic layer, 25 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. 75 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. The obtained organic layer was concentrated, 2 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue, and the mixture was stirred at 23 ° C. for 30 minutes, then, the supernatant liquid was removed and concentrated to obtain the compound of the formula ( 3.72 parts of the salt represented by I-6) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 481.0

Example 6: Synthesis of salt represented by formula (I-34)
2.6 parts of the salt represented by the formula (I-34-e) and 30 parts of acetonitrile were mixed and stirred at 23 ° C. for 30 minutes, and then the compound represented by the formula (I-1-f) 1.17. Parts were added, the temperature was raised to 50 ° C., and the mixture was stirred at 50 ° C. for 2 hours. 2.22 parts of the compound represented by the formula (I-6-c) was added to the obtained reaction mixture, and the mixture was stirred at 50 ° C. for 10 hr. The obtained reaction mixture was cooled to 23 ° C., 50 parts of chloroform and 25 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes, then, separated, and the organic layer was taken out. 25 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, and then liquid-separated to take out the organic layer. This water washing operation was repeated 5 times. To the obtained organic layer, 25 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. 75 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. The obtained organic layer was concentrated, 2 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue, and the mixture was stirred at 23 ° C. for 30 minutes, then, the supernatant liquid was removed and concentrated to obtain the compound of the formula ( 3.69 parts of the salt represented by I-34) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 281.1
MASS (ESI (-) Spectrum): M ^- 481.0

Example 7: Synthesis of salt represented by formula (I-48)
2.8 parts of the salt represented by the formula (I-48-e) and 30 parts of acetonitrile were mixed and stirred at 23 ° C. for 30 minutes, and then the compound represented by the formula (I-1-f) 1.17. Parts were added, the temperature was raised to 50 ° C., and the mixture was stirred at 50 ° C. for 2 hours. 2.22 parts of the compound represented by the formula (I-6-c) was added to the obtained reaction mixture, and the mixture was stirred at 50 ° C. for 10 hr. The obtained reaction mixture was cooled to 23 ° C., 50 parts of chloroform and 25 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes, then, separated, and the organic layer was taken out. 25 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, and then liquid-separated to take out the organic layer. This water washing operation was repeated 5 times. To the obtained organic layer, 25 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. 75 parts of ion-exchanged water was added to the obtained organic layer, the mixture was stirred at 23 ° C. for 30 minutes, then liquid-separated, and the organic layer was taken out. The obtained organic layer was concentrated, 2 parts of acetonitrile and 30 parts of tert-butyl methyl ether were added to the concentrated residue, and the mixture was stirred at 23 ° C. for 30 minutes, then, the supernatant liquid was removed and concentrated to obtain the compound of the formula ( 3.22 parts of the salt represented by I-48) was obtained.

MASS (ESI (+) Spectrum): M ⁺ 317.1
MASS (ESI (-) Spectrum): M ^- 481.0

Resin Synthesis The compounds (monomers) used in the synthesis of resin (A) are shown below. Hereinafter, these compounds are referred to as “monomer (a1-1-3)” and the like according to the 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) were used, and the molar ratio thereof was [monomer (a1-4-2): monomer (a1-1). -3): Monomer (a1-2-6)] is mixed in a ratio of 38:24:38, and further, 1.5 times by mass of the total mass of all monomers is added to the monomer mixture. Of methyl isobutyl ketone were 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 monomers, and the mixture 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 liquid, and the mixture was stirred for 6 hours and then separated. The obtained organic layer was poured into a large amount of n-heptane to precipitate a resin, and the resin was filtered and collected to obtain a resin A1 (copolymer) having a weight average molecular weight of about 5.3 × 10 ³ in a yield of 78. Earned in%. This resin A1 has the following structural units.

<Preparation of resist composition>
As shown in Table 2, the following components were mixed, and the resulting mixture was filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

<Resin>
A1: Resin A1
<Salt (I)>
I-1: Salt represented by formula (I-1) I-2: Salt represented by formula (I-2) I-3: Salt represented by formula (I-3) I-4: Formula Salt represented by (I-4) I-6: Salt represented by formula (I-6) I-34: Salt represented by formula (I-34) I-48: Formula (I-48) The salt <acid generator>
IX-1: Salt represented by formula (IX-1) (synthesized by the method described in JP 2009-191054 A)
IX-2: a salt represented by the formula (IX-2) (synthesized by the method described in JP 2011-046694 A).
IX-3: a salt represented by the formula (IX-3) (synthesized by the method described in JP2011-126869A).
IX-4: Salt represented by formula (IX-4) (synthesized by the method described in JP-A-2017-019997)
IX-5: a salt represented by the formula (IX-5) (synthesized by the method described in JP 2012-226325 A).
<Quencher (C)>
C1: Synthesized by the method described in JP2011-39502A
<Solvent>
Propylene glycol monomethyl ether acetate 400 parts Propylene glycol monomethyl ether 100 parts γ-butyrolactone 5 parts

(Evaluation of electron beam exposure of resist composition)
A 6-inch silicon wafer was treated with hexamethyldisilazane on a direct hot plate at 90 ° C. for 60 seconds. This silicon wafer was spin-coated with a resist composition so that the thickness of the composition layer was 0.04 μm. Then, on the direct hot plate, it prebaked for 60 second at the temperature shown in the "PB" column of Table 2, and formed the composition layer. An electron beam drawing machine [“ELS-F125 125 keV” manufactured by Elionix Co., Ltd.] was used for the composition layer formed on the wafer, and the exposure amount was changed stepwise to obtain a contact hole pattern (hole pitch 40 nm / hole. (Diameter 17 nm) was directly drawn.
After exposure, post-exposure bake was performed on the hot plate at the temperature shown in the "PEB" column of Table 2 for 60 seconds, and then paddle development was 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 terms of effective sensitivity, the hole diameter of a 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 using a population obtained by measuring the average hole diameter of a pattern formed with a hole diameter of 17 nm on the same wafer at 400 points.
The results are shown in Table 3. Numerical values in the table indicate standard deviation (nm).

Compared to Comparative Compositions 1 to 5, the standard deviations of Compositions 1 to 7 were small and the CD uniformity (CDU) evaluation was good.

  The resist composition of the present invention can obtain a resist pattern having good CD uniformity (CDU), and thus is suitable for fine processing of semiconductors and is extremely useful industrially.

Claims (10)

A salt represented by the formula (I).
[In the formula (I),
Q ¹ and Q ² each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
R ¹ and R ² each independently represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
z represents an integer of 0 to 6, and when z is 2 or more, a plurality of R ¹ and R ² may be the same or different from each other.
X ¹ and X ² each independently represent * -CO-O-, * -O-CO-, * -O-CO-O- or * -O-, and * represents C (R ¹ ) ( R ² ) or C (Q ¹ ) (Q ² ), or a binding site with A ¹ or L ² .
L ¹ represents a single bond or a hydrocarbon group having 1 to 28 carbon atoms which may have a substituent, and —CH ₂ — contained in the hydrocarbon group is —O—, —S—, —SO. _It may be replaced by _2- or -CO-.
A ¹ represents a lactone ring having 3 to 36 carbon atoms which may have a substituent.
L ² represents a single bond or an alkanediyl group having 1 to 6 carbon atoms.
R ³ represents a fluorinated hydrocarbon group having 1 to 18 carbon atoms.
Z ⁺ represents an organic cation. ] The salt according to claim 1, wherein A ¹ is a norbornane lactone ring. The salt according to claim 1, wherein L ² is a single bond. L ¹ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a group formed by combining an alkanediyl group having 1 to 4 carbon atoms and an adamantanediyl group (-CH ₂ — contained in the alkanediyl group is -O- or -CO- may be substituted) or a group formed by combining an alkanediyl group having 1 to 4 carbon atoms and a phenylene group which may have a fluorine atom (included in the alkanediyl group. -CH ₂ -, the salt according to claim 1 is may be replaced by -O- or -CO-).. The salt according to claim 1, wherein R ³ is a fluorinated alkyl group having 1 to 8 carbon atoms or a group represented by formula (R3-1).
[In the formula (R3-1),
L ³ represents a single bond or an alkanediyl group having 1 to 6 carbon atoms.
m3 represents an integer of 1 to 5.
R ⁴ represents a halogen atom or an alkyl group having 1 to 6 carbon atoms, and —CH ₂ — contained in the alkyl group may be replaced with —O— or —CO—.
m4 represents any integer of 0 to 4, and when m4 is 2 or more, a plurality of R ⁴ may be the same as or different from each other.
* Represents a binding site with X ² . ]   An acid generator containing the salt according to claim 1.   A resist composition containing the acid generator according to claim 6 and a resin having an acid labile group. The resin having an acid labile 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). Resist composition.
[In Formula (a1-1) and Formula (a1-2),
L ^a1 and L ^a2 each independently represent —O— or * —O— (CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, and * represents —CO—. Represents a binding site with.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group combining these.
m1 represents any integer of 0-14.
n1 represents any integer of 0-10.
n1 ′ represents an integer of 0 to 3. ]   The resist composition according to claim 7, 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 7 to 9 onto a substrate,
(2) a step of drying the composition after coating to form a composition layer,
(3) exposing the composition layer
(4) heating the composition layer after exposure, and (5) developing the composition layer after heating,
A method of manufacturing a resist pattern including: