JP2018030830A - Salt, resist composition and method for producing resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a salt and a resist composition, which can produce a resist pattern with a good mask error factor (MEF).SOLUTION: The salt is represented by formula (I), and the resist composition contains the salt and a resin containing a structural unit having an acid-labile group. [X is O, S, or the like; Ris an F-substituted/unsubstituted alkyl group, an F-substituted/unsubstituted alicyclic hydrocarbon group, an F-substituted/unsubstituted aromatic hydrocarbon group, or the like; Ar is a substituted/unsubstituted divalent aromatic hydrocarbon group or heteroaromatic hydrocarbon group; Rand Rare each independently H, an OH group, or a hydrocarbon group; m and n are each independently 1 or 2; Xis "*"-O-, "*"-O-CO-, "*"-CO-O-, or the like; "*" is a bonding position to Ar; W is a substituted/unsubstituted alicyclic hydrocarbon group or a substituted/unsubstituted heterocyclic group; and Ais an organic anion].SELECTED DRAWING: None

Description

  The present invention relates to a salt used for semiconductor microfabrication, a resist composition, and a method for producing a resist pattern.

Patent Document 1 describes a resist composition containing a salt represented by the following formula as a salt for an acid generator.
Patent Document 2 describes a resist composition containing a salt represented by the following formula as a salt for an acid generator.

JP 2011-081044 A JP 2014-199389 A

  In the resist composition containing the salt represented by the above formula, the mask error factor (MEF) may not always be satisfied.

The present invention includes the following inventions.
[1] A salt represented by the formula (I).
[In the formula (I),
X represents an oxygen atom, a sulfur atom or —N (SO ₂ R ⁵ ) —.
R ⁵ may have an alkyl group having 1 to 12 carbon atoms which may have a fluorine atom, an alicyclic hydrocarbon group having 3 to 12 carbon atoms which may have a fluorine atom, or a fluorine atom. It represents an aromatic hydrocarbon group having 6 to 12 carbon atoms, and —CH ₂ — contained in the alkyl group or the alicyclic hydrocarbon group may be replaced by —O— or —CO—.
Ar is a divalent aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or a divalent heteroaromatic hydrocarbon having 4 to 36 carbon atoms which may have a substituent. Represents a group.
R ¹ and R ² each independently represent a hydrogen atom, a hydroxy group or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group is —O— or —CO—. It may be replaced.
m and n each independently represents 1 or 2. When m is 2, two R ¹ are the same or different, and when n is 2, two R ² are the same or different.
X ¹ represents * —O—, * —O—CO—, * —CO—O—, * —O—CO—O— or * —O—CH ₂ —CO—O—. * Represents a bonding position with Ar.
W represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. The hydrogen atom contained in the alicyclic hydrocarbon group is a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alicyclic hydrocarbon having 3 to 12 carbon atoms. It may be substituted with a group, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a combination thereof.
A ⁻ represents an organic anion. ]
[2] The salt according to [1], wherein X ¹ is * —O—CO— (* represents a bonding position with Ar).
[3] W is a cyclohexyl group, norbornyl group or adamantyl group, and the methylene group contained in the cyclohexyl group, norbornyl group or adamantyl group may be substituted with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group Well, the hydrogen atom contained in the cyclohexyl group, norbornyl group or adamantyl group is a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic ring having 3 to 12 carbon atoms The salt according to [1] or [2], which may be substituted with a formula hydrocarbon group, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a combination of these.
[4] The salt according to any one of [1] to [3], wherein Ar is a phenylene group.
[5] The salt according to any one of [1] to [4], wherein the organic anion is an organic sulfonate anion.
[6] The salt according to any one of [1] to [4], wherein the organic anion is an anion represented by the formula (IA).
[In the formula (IA),
Q ¹ and Q ² 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 saturated hydrocarbon group may be replaced by —O— or —CO—, and The hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Y represents an optionally substituted methyl group or an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and is included in the alicyclic hydrocarbon group − CH ₂ — may be replaced by —O—, —SO ₂ — or —CO—. ]
[7] Y represents an adamantyl group which may have a substituent, and —CH ₂ — contained in the adamantyl group may be replaced with —O— or —CO—. salt.
[8] A resist composition comprising the salt according to any one of [1] to [7] and a resin having an acid labile group.
[9] The resist composition according to [8], wherein the resin having an acid labile group further contains a structural unit having a lactone ring.
[10] The resist composition according to [8] or [9], further comprising a salt that generates an acid having a lower acidity than an acid generated from an acid generator.
[11] The resist composition according to any one of [8] to [10], further comprising a resin containing a structural unit having a fluorine atom.
[12] (1) A step of applying the resist composition according to any one of [8] to [11] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) A method for producing a resist pattern, comprising: a step of heating the composition layer after exposure; and (5) a step of developing the composition layer after heating.

  Provided are a salt capable of producing a resist pattern with a good mask error factor (MEF), and a resist composition containing the salt.

In the present specification, unless otherwise specified, a hydrocarbon group that can take both a linear structure and a branched structure such as an “aliphatic hydrocarbon group” in the description of the structural formula of a compound includes both of them, The “alicyclic hydrocarbon group” means a group obtained by removing the number of hydrogen atoms corresponding to the valence from the ring of the alicyclic hydrocarbon. The “aromatic hydrocarbon group” also includes a group in which a hydrocarbon group is bonded to an aromatic ring. When stereoisomers exist, all stereoisomers are included.
The term "(meth) acrylic monomer" means at least one monomer having a structure of _"CH 2 = _CH-CO-" or _{"CH 2 = C (CH 3)} -CO- ". Similarly, “(meth) acrylate” and “(meth) acrylic acid” mean “at least one of acrylate and methacrylate” and “at least one of acrylic acid and methacrylic acid”, respectively.
In the present specification, the “solid content of the resist composition” means the total of components excluding the solvent (E) described later from the total amount of the resist composition.

<Salt represented by formula (I) (hereinafter sometimes referred to as salt (I))>
[In the formula (I),
X represents an oxygen atom, a sulfur atom or —N (SO ₂ R ⁵ ) —.
R ⁵ may have an alkyl group having 1 to 12 carbon atoms which may have a fluorine atom, an alicyclic hydrocarbon group having 3 to 12 carbon atoms which may have a fluorine atom, or a fluorine atom. It represents an aromatic hydrocarbon group having 6 to 12 carbon atoms, and —CH ₂ — contained in the alkyl group or the alicyclic hydrocarbon group may be replaced by —O— or —CO—.
Ar is a divalent aromatic hydrocarbon group having 4 to 36 carbon atoms which may have a substituent or a divalent heteroaromatic hydrocarbon having 4 to 36 carbon atoms which may have a substituent. Represents a group.
R ¹ and R ² each independently represent a hydrogen atom, a hydroxy group or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group is —O— or —CO—. It may be replaced.
m and n each independently represents 1 or 2. When m is 2, two R ¹ are the same or different, and when n is 2, two R ² are the same or different.
X ¹ represents * —O—, * —O—CO—, * —CO—O—, * —O—CO—O— or * —O—CH ₂ —CO—O—. * Represents a bonding position with Ar.
W represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. The hydrogen atom contained in the alicyclic hydrocarbon group is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or carbon. It may be substituted with an aromatic hydrocarbon group of several 6 to 10 or a combination thereof.
A ⁻ represents an organic anion. ]

Examples of the divalent aromatic hydrocarbon group represented by Ar include a phenylene group, a naphthylene group, an anthracenylene group, a phenanthylene group, a tolylene group, a xylylene group, a dimethylphenylene group, a trimethylphenylene group, an ethylphenylene group, and a propylphenylene group. Group, butylphenylene group, biphenylene group, triphenylene group, indenylene group and tetrahydronaphthylene group. The divalent aromatic hydrocarbon group represented by Ar preferably has 6 to 24 carbon atoms, and more preferably 6 to 18 carbon atoms.
Examples of the hetero atom include a nitrogen atom, an oxygen atom, and a sulfur atom.
Examples of the divalent heteroaromatic hydrocarbon group include a furylene group and a thienylene group, preferably 4 to 24 carbon atoms, more preferably 4 to 18 carbon atoms.
Ar is preferably a divalent aromatic hydrocarbon group, more preferably a phenylene group.
Examples of the substituent for the divalent aromatic hydrocarbon group and the divalent heteroaromatic hydrocarbon group represented by Ar include a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, and an alkylcarbonyloxy having 2 to 18 carbon atoms. Group, an arylcarbonyloxy group having 7 to 18 carbon atoms, or an alkoxycarbonyloxy group having 2 to 18 carbon atoms, and —CH ₂ — contained in the alkoxy group having 1 to 12 carbon atoms is replaced by —O—. May be. The substituent of the aromatic hydrocarbon group and heteroaromatic hydrocarbon group represented by Ar is preferably a hydroxy group.
Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group and dodecyloxy group. Preferably, it is a C1-C6 alkoxy group, More preferably, it is a methoxy group.
Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropylcarbonyloxy group, an n-butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, Examples include a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group, and a 2-ethylhexylcarbonyloxy group. Preferably, it is a C2-C12 alkylcarbonyloxy group, More preferably, it is a methylcarbonyloxy group.
Examples of the arylcarbonyloxy group include a phenylcarbonyloxy group and a tosylcarbonyloxy group. An arylcarbonyloxy group having 7 to 12 carbon atoms is preferable, and a phenylcarbonyloxy group is more preferable.
As alkoxycarbonyloxy group, methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, isopropoxycarbonyloxy group, n-butoxycarbonyloxy group, sec-butoxycarbonyloxy group, tert-butoxycarbonyloxy group Pentyloxycarbonyloxy group, hexyloxycarbonyloxy group, octyloxycarbonyloxy group and 2-ethylhexyloxycarbonyloxy group. Preferably, it is a C2-C8 alkyloxycarbonyloxy group, More preferably, it is a tert- butyloxycarbonyloxy group.

Examples of the hydrocarbon group represented by R ¹ and R ² include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by a combination thereof.
As the alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group , Nonyl group, decyl group, undecyl group, dodecyl group and the like.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon group includes a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a methylcyclohexyl group. And cycloalkyl groups such as dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, cycloheptyl group and cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, 2-alkyladamantan-2-yl group, 1- (adamantan-1-yl) alkane-1-yl group, norbornyl group, Examples thereof include a methylnorbornyl group and an isobornyl group.
Examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group.
Examples of the group formed by combination include an aralkyl group, and a benzyl group and a phenethyl group.
Examples of the group in which —CH ₂ — contained in the hydrocarbon group is replaced by —O— or —CO— include a methoxy group, an ethoxy group, a butoxy group, an acetyl group, a methoxycarbonyl group, an acetyloxy group, and a butoxycarbonyloxy group. And a benzoyloxy group.

Examples of the alkyl group having 1 to 12 carbon atoms represented by R ⁵ include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, and hexyl. Group, heptyl group, 2-ethylhexyl group, octyl group, nonyl group, decyl group, undecyl group and dodecyl group.
Examples of the alkyl group having 1 to 12 carbon atoms having a fluorine atom represented by R ⁵ include trifluoromethyl group, difluoromethyl group, perfluoroethyl group, 1,1,1-trifluoroethyl group, 1,1,2,2. , 2-tetrafluoroethyl group, perfluoropropyl group, 1,1,1,2,2-pentafluoropropyl group, perfluorobutyl group, 1,1,2,2,3,3,4,4-octafluorobutyl Group, perfluoropentyl group, 1,1,1,2,2,3,3,4,4-nonafluoropentyl group, n-perfluorohexyl group and the like.
The alicyclic hydrocarbon group having 3 to 12 carbon atoms represented by R ⁵ may be monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon group may be a cyclopropyl group, Examples thereof include cycloalkyl groups such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cycloheptyl group, and a cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, 2-alkyladamantan-2-yl group, 1- (adamantan-1-yl) alkane-1-yl group, norbornyl group, Examples thereof include a methylnorbornyl group and an isobornyl group.
Examples of the aromatic hydrocarbon group having 6 to 12 carbon atoms represented by R ⁵ include a phenyl group and a naphthyl group.

The alicyclic hydrocarbon group represented by W may be monocyclic or polycyclic, and may be a spiro ring. When the methylene group contained in the alicyclic hydrocarbon group is replaced with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group, the number of —CH ₂ — to be replaced may be one, 2 or more, 3 or more, 4 or more, etc. There may be multiple. In this case, the methylene group contained in the alicyclic hydrocarbon group is preferably substituted with an oxygen atom, a sulfur atom, a carbonyloxy group or a sulfonyl group, and more preferably substituted with a carbonyloxy or sulfonyl group.
Examples of the alicyclic hydrocarbon group include groups represented by formulas (W1) to (W38).

Ring W includes a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and an aromatic carbonization having 6 to 10 carbon atoms. It may be substituted with a hydrogen group or a combination thereof.
Examples of the alkyl group, alkoxy group, alicyclic hydrocarbon group, aromatic hydrocarbon group, or a combination thereof are the same as those described above.
Of these, a hydroxy group, a hydroxyalkyl group or an alkoxy group is preferable, and a hydroxy group or a hydroxyalkyl group is preferable.

m is preferably 2.
n is preferably 2.
Of m and n, at least one is preferably 2, and both m and n are more preferably 2.
R ¹ and R ² are preferably the same group.
R ¹ is preferably a hydrogen atom.
R ² is preferably a hydrogen atom.
R ³ is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
R ⁴ is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
Either one of R ³ and R ⁴ is preferably a hydrogen atom, more preferably a hydrogen atom.
Ar is preferably an aromatic hydrocarbon group having 6 to 36 carbon atoms, more preferably an aromatic hydrocarbon group having 6 to 18 carbon atoms, further preferably a phenylene group, a tolylene group, a xylylene group, or a dimethylphenylene group, and a phenylene group. Is particularly preferred.
X is preferably a single bond, a methylene group or an oxygen atom, more preferably a single bond or a methylene group, and even more preferably a single bond.
X ¹ is preferably * —O—CO—, * —CO—O—, * —O—CO—O— or * —O—CH ₂ —CO—O—, and * —O—CO— Or * -CO-O-, more preferably * -O-CO- (* represents a bonding position with Ar).
W is preferably a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, an adamantyl group or a norbornyl group, more preferably a cyclohexyl group, an adamantyl group or a norbornyl group, and more preferably an adamantyl group. Even more preferred. Further, these preferably have a hydroxy group or hydroxyalkyl group substituted, and more preferably have a hydroxy group substituted.

Examples of the cation (hereinafter sometimes referred to as cation (I)) in the salt (I) include the following cations. The cation (I) is represented by the formula (Ic-1), formula (Ic-2), formula (Ic-3), formula (Ic-5), formula (Ic-7). , Formula (Ic-9), formula (Ic-10), formula (Ic-11), formula (Ic-15), formula (Ic-16) and formula (I- The cation represented by c-17) is preferred.

A ⁻ represents a monovalent anion, specifically, halide ion, hydroxide ion, organic sulfonate anion, organic sulfonylimide anion, organic sulfonylmethide anion, alkoxide anion, phenoxide anion, carboxylate anion, etc. Of organic anions.
A ⁻ is preferably a halide ion or an organic anion, more preferably an organic sulfonate anion or a carboxylate anion, and still more preferably an organic sulfonate anion.
The organic sulfonate anion is preferably an organic sulfonate anion having a sulfo group and a fluorine atom, and more preferably an anion represented by the formula (IA).
[In the formula (IA),
Q ¹ and Q ² 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 saturated hydrocarbon group may be replaced by —O— or —CO—, and The hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Y represents an optionally substituted methyl group or an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and is included in the alicyclic hydrocarbon group − CH ₂ — may be replaced by —O—, —SO ₂ — or —CO—. ]

Examples of the perfluoroalkyl group of Q ¹ and Q ² 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. A hexyl group etc. are mentioned.
Q ¹ and Q ² are preferably each independently a fluorine atom or a trifluoromethyl group, and more preferably a fluorine atom.

Examples of the divalent saturated hydrocarbon group for L ^b1 include a linear alkanediyl group, a branched alkanediyl group, a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, and these 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 , Tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group and heptadecane-1,17-diyl group Alkanediyl group;
Ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane- Branched alkanediyl groups such as 1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 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 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, adamantane-2,6-diyl group, etc. Groups and the like.

Examples of the group in which —CH ₂ — contained in the divalent saturated hydrocarbon group of L ^b1 is replaced by —O— or —CO— include any of formulas (b1-1) to (b1-3) The group represented by these is mentioned. In the formulas (b1-1) to (b1-3) and the following specific examples, * 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, and the saturated The methylene group contained in the hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
However, the total number of carbon atoms of L ^b2 and L ^b3 is 22 or less.
In formula (b1-2),
L ^b4 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated The methylene group contained in the hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
However, the total number of carbon atoms of L ^b4 and L ^b5 is 22 or less.
In formula (b1-3),
L ^b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
L ^b7 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated The methylene group contained in the hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
However, the total number of carbon atoms of L ^b6 and L ^b7 is 23 or less. ]

In Formula (b1-1) to Formula (b1-3), when the methylene group contained in the saturated hydrocarbon group is replaced with an oxygen atom or a carbonyl group, the number of carbons before the replacement is represented by the carbon number of the saturated hydrocarbon group. It is a number.
Examples of the divalent saturated hydrocarbon group include the same 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, The methylene group contained in the divalent saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
As the group in which —CH ₂ — contained in the divalent saturated hydrocarbon group of L ^b1 is replaced by —O— or —CO—, a group represented by the formula (b1-1) or the formula (b1-3) Is preferred.

Examples of formula (b1-1) include groups represented by formula (b1-4) to formula (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 the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
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 C1-C21 divalent saturated hydrocarbon group, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
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 C 1-19 divalent saturated hydrocarbon group, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
L ^b14 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
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 C1-C18 divalent saturated hydrocarbon group, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
L ^b17 represents a C1- ^C18 divalent saturated hydrocarbon group.
L ^b18 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. .
However, the total carbon number of L ^{b16 to} L ^b18 is 19 or less. ]

L ^b8 is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.
L ^b9 is preferably a C 1-8 divalent saturated hydrocarbon group.
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 ^C 1-6 divalent saturated hydrocarbon group.
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 formula (b1-3) include groups represented by formula (b1-9) to formula (b1-11), respectively.
[In the formula (b1-9),
L ^b19 represents a single bond or a ^C1-C23 divalent saturated hydrocarbon group, and the hydrogen atom contained in the divalent 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 divalent saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group, or an acyloxy group. Also good. The methylene group contained in the acyloxy group may be replaced with an oxygen atom or a carbonyl group, and the hydrogen atom contained in the acyloxy group may be substituted with a hydroxy group.
However, the total carbon number of L ^b19 and L ^b20 is 23 or less.
In formula (b1-10),
L ^b21 represents a single bond or a ^C1-C21 divalent saturated hydrocarbon group, and the hydrogen atom contained in the divalent 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, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
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 divalent saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group, or an acyloxy group. May be. The methylene group contained in the acyloxy group may be replaced with an oxygen atom or a carbonyl group, and the hydrogen atom contained in the acyloxy group may be substituted with a hydroxy group.
However, the total carbon number of L ^{b21 to} 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 divalent saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b25 represents a C1-C21 divalent saturated hydrocarbon group, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
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 divalent saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group, or an acyloxy group. May be. The methylene group contained in the acyloxy group may be replaced with an oxygen atom or a carbonyl group, and the hydrogen atom contained in the acyloxy group may be substituted with a hydroxy group.
^However, the total number of carbon atoms of L b24 ^{~L b26} is 21 or less. ]

  In formulas (b1-9) to (b1-11), when a hydrogen atom contained in a divalent saturated hydrocarbon group is substituted with an acyloxy group, the number of carbon atoms in the acyloxy group, CO in the ester bond, and The number of carbon atoms of the divalent saturated hydrocarbon group including the number of O is used.

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

Of the groups represented by formula (b1-1), examples of the group represented by formula (b1-4) include the following.

Of the groups represented by the formula (b1-1), examples of the group represented by the formula (b1-5) include the following.

Of the groups represented by formula (b1-1), examples of the group represented by formula (b1-6) include the following.

Of the groups represented by the formula (b1-1), examples of the group represented by the formula (b1-7) include the following.

Of the groups represented by the formula (b1-1), examples of the group represented by the formula (b1-8) include the following.

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

Of the groups represented by formula (b1-3), examples of the group represented by formula (b1-9) include the following.

Of the groups represented by the formula (b1-3), examples of the group represented by the formula (b1-10) include the following.

Of the groups represented by formula (b1-3), examples of the group represented by formula (b1-11) include the following.

Examples of the alicyclic hydrocarbon group represented by Y include groups represented by formulas (Y1) to (Y11) and formulas (Y36) to (Y38).
When —CH ₂ — contained in the alicyclic hydrocarbon group represented by Y is replaced by —O—, —SO ₂ — or —CO—, the number may be one or two or more. . Examples of such a group include groups represented by formula (Y12) to formula (Y35).

Among them, the group represented by any one of the formulas (Y1) to (Y20), the formula (Y30), and the formula (Y31) is preferable, and the formula (Y11), the formula (Y15), and the formula (Y Y16), a group represented by formula (Y20), formula (Y30) or formula (Y31), and more preferably a group represented by formula (Y11), formula (Y15) or formula (Y30).
When Y constitutes a spiro ring such as formula (Y28) to formula (Y33), the alkanediyl group between two oxygens preferably has one or more fluorine atoms. Of the alkanediyl groups contained in the ketal structure, those in which the fluorine atom is not substituted on the methylene group adjacent to the oxygen atom are preferred.

Examples of the substituent for the alicyclic hydrocarbon group represented by Y include a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms which may be substituted with a hydroxy group, and an alicyclic group having 3 to 16 carbon atoms. A hydrocarbon group, an alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, an aralkyl group having 7 to 21 carbon atoms, an acyl group having 2 to 4 carbon atoms, a glycidyloxy group, or — (CH ₂ ) _ja- O-CO-R ^b1 group (wherein R ^b1 is an alkyl group having 1 to 16 carbon atoms, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, or an aromatic carbon atom having 6 to 18 carbon atoms). Represents a hydrogen group, and ja represents an integer of 0 to 4).

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a norbornyl group, an adamantyl group, and the like.
Examples of the aromatic hydrocarbon group include phenyl group, naphthyl group, anthryl group, p-methylphenyl group, p-tert-butylphenyl group, p-adamantylphenyl group; tolyl group, xylyl group, cumenyl group, mesityl group. , Aryl groups such as biphenyl group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl, and the like.
Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, heptyl group, 2 -Ethylhexyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, etc. are mentioned.
Examples of the alkyl group substituted with a hydroxy group include hydroxyalkyl groups such as a hydroxymethyl group and a hydroxyethyl group.
Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group and dodecyloxy group.
Examples of the aralkyl group include benzyl group, phenethyl group, phenylpropyl group, naphthylmethyl group, and naphthylethyl group.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.

Examples of Y include the following.

When Y is a methyl group and L ^b1 is a divalent linear or branched saturated hydrocarbon group having 1 to 17 carbon atoms, the divalent saturated hydrocarbon group at the bonding position with Y It is preferable that —CH ₂ — is replaced by —O— or —CO—.

Y is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, more preferably an adamantyl group which may have a substituent, and the alicyclic carbonization The methylene group constituting the hydrogen group or adamantyl group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group. Y is more preferably an adamantyl group, a hydroxyadamantyl group, an oxoadamantyl group, or a group represented by the following.

Examples of the sulfonate anion in the salt represented by the formula (IA) include an anion represented by the formula (B1-A-1) to the formula (B1-A-55) [hereinafter referred to as “anion” according to the formula number. (B1-A-1) "or the like. ] Is preferable, Formula (B1-A-1)-Formula (B1-A-4), Formula (B1-A-9), Formula (B1-A-10), Formula (B1-A-24)-Formula (B1-A-33), Formula (B1-A-36) to Formula (B1-A-40), Formula (B1-A-47) to Formula (B1-A-55) An anion is more preferable.

Here, R ^{i2 to} R ⁱ⁷ are, for example, an alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group. 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. More preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group. L ⁴ is a single bond or an alkanediyl group having 1 to 4 carbon atoms.
Q ¹ and Q ² are the same as described above.
Specific examples of the sulfonate anion in the salt represented by the formula (IA) include the anions described in JP 2010-204646 A.

Examples of the sulfonate anion in the salt (I) include anions represented by formulas (B1a-1) to (B1a-34), respectively.

Examples of the organic sulfonylimide anion include the following.

As A ⁻ , Formula (B1a-1) to Formula (B1a-3) and Formula (B1a-7) to Formula (B1a-16), Formula (B1a-18), Formula (B1a-19), Formula (B1a) An anion represented by any one of −22) to formula (B1a-34) is preferable.

Examples of the salt (I) include the salts described in Table 1. In Table 1, salt (I-1) is a salt shown below, for example.

  Examples of the salt (I) include salt (I-1), salt (I-2), salt (I-3), salt (I-12), salt (I-13), salt (I-14), salt (I-15), salt (I-16), salt (I-17), salt (I-18), salt (I-19), salt (I-28), salt (I-29), salt ( I-30), salt (I-31), salt (I-32), salt (I-129), salt (I-130), salt (I-131), salt (I-140), salt (I -141), salt (I-142), salt (I-143), salt (I-144), salt (I-145), salt (I-146), salt (I-147), salt (I- 156), salt (I-157), salt (I-158), salt (I-159), salt (I-160), salt (I-161), salt (I-162), salt (I-163) ), Salt (I-172), salt (I-173), salt (I-174), salt I-175) and salts (I-176) are preferred.

The salt (I) can be produced by reacting the salt represented by the formula (Ia) and the compound represented by the formula (Ib) in a solvent in the presence of a catalyst.
(Wherein R ¹ , R ² , Ar, X ¹ , W, X and A ⁻ are as defined above.)
Examples of the catalyst include copper (II) benzoate.
Examples of the solvent include monochlorobenzene.

Examples of the salt represented by the formula (Ib) include a compound represented by the following formula.
The salt represented by the formula (Ia) is produced, for example, by reacting the salt represented by the formula (Ic) and the salt represented by the formula (Id) in a solvent. be able to.
(In the formula, X represents a chlorine atom or a bromine atom.)
Examples of the solvent include chloroform and water.
Examples of the compound represented by the formula (Id) include a compound represented by the following formula.

A salt represented by the formula (I1-c) in which X ¹ is * —O—CO— (* represents a bonding position with Ar) includes a compound represented by the formula (I1-e) and the formula It can manufacture by making the salt represented by (I1-f) react in a solvent in presence of a base catalyst.
Examples of the base include N-methylpyrrolidine and pyridine.
Examples of the solvent include acetonitrile and chloroform.
Examples of the compound represented by the formula (I1-e) include a compound represented by the following formula.
Examples of the salt represented by the formula (I1-f) include a salt represented by the following formula.

The salt represented by the formula (I2-c) in which X ¹ is * —CO—O— (* represents the bonding position with Ar) is the same as the salt represented by the formula (I2-f) and the carbonyl It can manufacture by making it react with the compound represented by a formula (I2-e), after making it react with a diimidazole in a solvent.
Examples of the solvent include acetonitrile and chloroform.
The compound represented by the formula (I2-e) is
Examples of the compound represented by the formula (I2-f) include a compound represented by the following formula.

The salt represented by the formula (I3-c) in which X ¹ is * —O—CO—O— (* represents the bonding position with Ar) is a compound represented by the formula (I2-e). And carbonyldiimidazole can be reacted in a solvent and then further reacted with a salt represented by the formula (I1-f).
Examples of the solvent include acetonitrile and chloroform.

A salt represented by the formula (I4-c) in which X ¹ is * —O— (* represents a bonding position with Ar) includes a compound represented by the formula (I2-e) and the formula (I1 The salt represented by -f) can be produced by reacting in a solvent in the presence of a base catalyst.
Examples of the base include potassium hydroxide.
Examples of the solvent include acetonitrile and chloroform.

The salt represented by the formula (I5-c), wherein X ¹ is * —O—CH ₂ —CO—O— (* represents the bonding position with Ar), is represented by the formula (I5-e). And a salt represented by the formula (I1-f) can be produced by reacting in a solvent in the presence of a base catalyst.
Examples of the base include N-methylpyrrolidine and pyridine.
Examples of the solvent include acetonitrile and chloroform.
Examples of the compound represented by the formula (I5-e) include a compound represented by the following formula.

[Resist composition]
The resist composition of the present invention contains a resin having an acid labile group (hereinafter sometimes referred to as “resin (A)”) and a salt (I). The salt (I) may contain two or more kinds, and the salt (I) acts as an acid generator in the resist composition.
The resist composition may contain an acid generator known in the resist field (hereinafter sometimes referred to as “acid generator (B)”). The resist composition preferably contains a quencher (hereinafter sometimes referred to as “quencher (C)”), and preferably contains a solvent (hereinafter sometimes referred to as “solvent (D)”).

<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). As the structural unit other than the structural unit (a1), a structural unit having no acid labile group (hereinafter sometimes referred to as “structural unit (s)”), other structural unit (hereinafter referred to as “structural unit (t)”). And structural units 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)”). “Acid labile group” means a group which has a leaving group and forms a hydrophilic group (for example, a hydroxy group or a carboxy group) by leaving the leaving group by contact with an acid.
In the resin (A), the acid labile group contained in the structural unit (a1) is preferably a group represented by the following formula (1) and / or a group represented by the formula (2).
[In the formula (1), R ^{a1 to} R ^a3 each independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a combination of these, or R ^a1 and R ^a2 are bonded to each other to form a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.
na represents 0 or 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. R ^{a2 ′} and R ^{a3 ′} are bonded to each other to form a divalent heterocyclic group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded, and the hydrocarbon group and the divalent heterocyclic group The methylene group contained in may be replaced with an oxygen atom or a sulfur atom.
X represents an oxygen atom or a sulfur atom.
* Represents a bond. ]

^Examples of the alkyl group represented by R ^{a1 to} R ^a3 include a methyl group, an ethyl group, a propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group.
The alicyclic hydrocarbon group of R ^{a1 to} R ^a3 may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups (* represents a bond). Carbon number of the alicyclic hydrocarbon group of R ^{a1 to} R ^a3 is preferably 3 to 16.
Examples of the combination of an alkyl group and an alicyclic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, an adamantyldimethyl group, and a norbornylethyl group. Etc.
na is preferably 0.

Examples of —C (R ^a1 ) (R ^a2 ) (R ^a3 ) in the case where R ^a1 and R ^a2 are bonded to each other to form a divalent alicyclic hydrocarbon group include the following groups. The divalent alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms. * Represents a bond with -O-.

Examples of the group represented by the formula (1) include a 1,1-dialkylalkoxycarbonyl group (a group in which R ^{a1 to} R ^a3 are alkyl groups in the formula (1), preferably a tert-butoxycarbonyl group), 2- An alkyladamantan-2-yloxycarbonyl group (in the formula (1), R ^a1 , R ^a2 and a carbon atom to which they are bonded form an adamantyl group, and R ^a3 is an alkyl group) and 1- (adamantane- 1-yl) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups, and R ^a3 is an adamantyl group).

Examples of the hydrocarbon group of R ^{a1 ′ to} R ^{a3 ′} include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these.
Examples of the alkyl group and alicyclic hydrocarbon group are the same as those described above.
The aromatic hydrocarbon group includes phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl. Group, phenanthryl group, 2,6-diethylphenyl group, aryl group such as 2-methyl-6-ethylphenyl group, and the like.
^{Examples of the} divalent heterocyclic group formed together with the carbon atom and X to which R ^{a2 ′} and R ^{a3 ′} are bonded to each other and X include the following groups. * Represents a bond.
At least one of R ^{a1 ′} and R ^{a2 ′} is preferably a hydrogen atom.

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

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

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

As a structural unit derived from a (meth) acrylic monomer having a group represented by the formula (1), a structural unit represented by the formula (a1-0) is preferably represented by the formula (a1-1). The structural unit represented by a structural unit or a formula (a1-2) is mentioned. These may be used alone or in combination of two or more. In this specification, the structural unit represented by formula (a1-0), the structural unit represented by formula (a1-1), and the structural unit represented by formula (a1-2) are each represented by structural unit (a1). -0), structural unit (a1-1), and structural unit (a1-2).
[In formula (a1-0), in formula (a1-1) and formula (a1-2),
L ^a01 , L ^a1 and L ^a2 each independently represent —O— or ^* —O— (CH ₂ ) _k1 —CO—O—, k1 represents any integer of 1 to 7, and * represents It represents a bond with —CO—.
R ^a01 , R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a02 , R ^a03 and R ^a04 each independently ^represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group formed by combining these.
m1 represents any integer of 0-14.
n1 represents an integer of 0 to 10.
n1 ′ represents any integer of 0 to 3. ]

L ^a01 , L ^a1 and L ^a2 are preferably an oxygen atom or * —O— (CH ₂ ) _k01 —CO—O— (where k01 is preferably an integer of 1 to 4, more preferably Is 1.), more preferably an oxygen atom.
R ^a4 and R ^a5 are preferably methyl groups.
R ^a02 , R ^a03 , R ^a04 , R ^a6, R ^a7 , the alkyl group, the alicyclic hydrocarbon group, and the combination thereof are the same as the groups listed for R ^{a1 to} R ^a3 in formula (1). Groups.
The carbon number of the alkyl group of R ^a02 , R ^a03 and R ^a04 is preferably 1 to 6, and more preferably a methyl group or an ethyl group.
The carbon number of the alkyl group in R ^a6 and R ^a7 is preferably 1 to 6, more preferably a methyl group, an ethyl group, or an isopropyl group, and still more preferably an ethyl group or an isopropyl group.
The carbon number of the alicyclic hydrocarbon group of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 is preferably 5 to 12, more preferably 5 to 10.
The group in which the alkyl group and the alicyclic hydrocarbon group are combined preferably has a total carbon number of 18 or less in combination of the alkyl group and the alicyclic hydrocarbon 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.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 ′ is preferably 0 or 1.

As the structural unit (a1-0), for example, a structural unit represented by any one of formulas (a1-0-1) to (a1-0-12) and a methyl group corresponding to R ^a01 can be a hydrogen atom. The substituted structural unit is mentioned, The structural unit represented by either the formula (a1-0-1)-a formula (a1-0-10) is preferable.

As a structural unit (a1-1), the structural unit derived from the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Among these, a structural unit represented by any one of formula (a1-1-1) to formula (a1-1-4) is preferable.

As the structural unit (a1-2), a structural unit represented by any one of formulas (a1-2-1) to (a1-2-6) and a methyl group corresponding to R ^a01 , R ^a4, and R ^a5 Is a structural unit in which is replaced with a hydrogen atom, and a structural unit represented by formula (a1-2-2) or formula (a1-2-5) is more preferable.

  When the resin (A) includes the structural unit (a1-0) and / or the structural unit (a1-1) and / or the structural unit (a1-2), the total content thereof is the total structure of the resin (A). It is 10-95 mol% normally with respect to the sum total of a unit, Preferably it is 15-90 mol%, More preferably, it is 20-85 mol%.

Examples of the structural unit having an acid labile group include a structural unit represented by the formula (a1-5) (hereinafter sometimes referred to as “structural unit (a1-5)”).
[In the formula (a1-5),
R ^a8 represents a C 1-6 alkyl group optionally having a halogen atom, a hydrogen atom, or a halogen atom.
Z ^a1 represents a single bond or * — (CH ₂ ) _h3 —CO—L ⁵⁴ —, h3 represents an integer of 1 to 4, and * represents a bond to L ⁵¹ .
L ⁵¹ , L ⁵² , L ⁵³ and L ⁵⁴ each independently represent —O— or —S—.
s1 represents any integer of 1 to 3.
s1 ′ represents any integer of 0 to 3.

As a halogen atom, a fluorine atom and a chlorine atom are mentioned, Preferably a fluorine atom is mentioned. 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 a trifluoromethyl group. 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.
One of L ⁵² and L ⁵³ is preferably —O— and the other is —S—.
As s1, 1 is preferable.
As s1 ', the integer in any one of 0-2 is preferable.
Z ^a1 is preferably a single bond or * —CH ₂ —CO—O—.

As a monomer which introduce | transduces structural unit (a1-5), the monomer described in Unexamined-Japanese-Patent No. 2010-61117 is mentioned, for example. Among these, structural units derived from the monomers respectively represented by formula (a1-5-1) to formula (a1-5-4) are preferable. Formula (a1-5-1) or formula (a1-5-2) The structural unit represented by is more preferable.

  When resin (A) has a structural unit (a1-5), it is preferable that the content rate is 1-50 mol% with respect to the sum total of all the structural units of resin (A), 3-45 It is more preferable that it is mol%, and it is further more preferable that it is 5-40 mol%.

Furthermore, examples of the structural unit (a1) include the structural units (a1-3) shown below.

The structural unit having a group represented by the formula (2) in the structural unit (a1) may be referred to as a structural unit represented by the formula (a1-4) (hereinafter 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 An oxy group or a methacryloyloxy group is represented.
la represents an integer of 0 to 4. When la is 2 or more, the plurality of R ^a33 may be the same as 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 Together with —C—O— to which they are bonded to form a divalent hydrocarbon group having 2 to 20 carbon atoms, and —CH ₂ — contained in the hydrocarbon group and the divalent hydrocarbon group is — O- or -S- may be substituted. ]

^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 further 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 trifluoromethyl group, difluoromethyl group, methyl group, perfluoroethyl group, 1,1,1-trifluoroethyl group, 1,1 , 2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 1,1,1,2,2-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3 , 4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 1,1,1,2,2,3,3,4,4-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group, etc. Is 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. Especially, a C1-C4 alkoxy group is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is further more preferable.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group, and a butyryloxy group.
As the hydrocarbon group for R ^a34, R ^a35 and R ^a36, an alkyl group, an alicyclic hydrocarbon group, aromatic hydrocarbon group, and include groups formed by combining these, alkyl groups and alicyclic hydrocarbon groups Examples thereof include the same groups as the alkyl group and the alicyclic hydrocarbon group in R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 .
The aromatic hydrocarbon group includes phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl. Group, phenanthryl group, 2,6-diethylphenyl group, aryl group such as 2-methyl-6-ethylphenyl group, and the like.
Examples of the combined group include a group obtained by combining the above-described alkyl group and alicyclic hydrocarbon group, an aralkyl group such as a benzyl group, and an aryl-cyclohexyl group such as a phenylcyclohexyl group. In particular, as R ^a36 , 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.
R ^a33 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group, and further preferably a methoxy group.
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, more preferably a methyl group or an ethyl group.
The hydrocarbon group for 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. A group to be formed, more preferably an alkyl group having 1 to 18 carbon atoms, an aliphatic hydrocarbon group having 3 to 18 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms. The alkyl group and alicyclic hydrocarbon group in R ^a36 are preferably unsubstituted. The aromatic hydrocarbon group for R ^a36 is preferably an aromatic ring having an aryloxy group having 6 to 10 carbon atoms.

As a structural unit (a1-4), the structural unit derived from the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Preferably, hydrogen atom corresponding to ^{R a32} in equation (a1-4-1) represented respectively to Formula (a1-4-8) structural units and structural units (a1-4) is replaced by a methyl group structure And more preferably, structural units represented by formula (a1-4-1) to formula (a1-4-5), respectively.

When the resin (A) includes the structural unit (a1-3) or the structural unit (a1-4), the content is preferably 10 to 95 mol% with respect to all the structural units of the resin (A), 15 -90 mol% is more preferable, and 20-85 mol% is further more preferable.

  The structural unit (a1) having an acid labile group in the resin (A) is at least selected from the group consisting of the structural unit (a1-0), the structural unit (a1-1), and the structural unit (a1-2). 1 type or more is preferable, and at least 2 types or more are more preferable, the combination of a structural unit (a1-1) and a structural unit (a1-2), the combination of a structural unit (a1-1) and a structural unit (a1-0), and a structure A combination of the unit (a1-2) and the structural unit (a1-0), a structural unit (a1-0), a combination of the structural unit (a1-1) and the structural unit (a1-2) is more preferable, and the structural unit ( The combination of a1-1) and structural unit (a1-2) is particularly preferred.

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

<Structural unit (a2)>
The hydroxy group contained in the structural unit (a2) may be an alcoholic hydroxy group or a phenolic hydroxy group.
When a resist pattern is produced from the resist composition of the present invention, when a high energy beam such as a KrF excimer laser (248 nm), an electron beam or EUV (ultra-ultraviolet light) is used as an exposure light source, the structural unit (a2) It preferably contains a structural unit (a2) having a phenolic hydroxy group. In the case of using an ArF excimer laser (193 nm) or the like, the structural unit (a2) preferably includes a structural unit (a2) having an alcoholic hydroxy group. As a structural unit (a2), 1 type may be included independently and 2 or more types may be included.
When the resin (A) has a structural unit (a2-0) having a phenolic hydroxy group, the content is preferably from 5 to 95 mol% with respect to all the structural units of the resin (A). 80 mol% is more preferable, and 15-80 mol% is further more preferable.

Examples of the structural unit (a2) having an alcoholic hydroxy group include a structural unit represented by the formula (a2-1) (hereinafter sometimes referred to as “structural unit (a2-1)”).
[In the formula (a2-1),
L ^a3 represents —O— or * —O— (CH ₂ ) _k2 —CO—O—,
k2 represents any 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 an integer of 0 to 10. ]

In the formula (a2-1), L ^a3 is preferably, -O -, - O- (CH 2) f1 -CO-O- and is (wherein f1 is an integer of 1 to 4) More preferably, it is —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 monomer that derives the structural unit (a2-1) include monomers described in JP 2010-204646 A. A structural unit represented by any one of formula (a2-1-1) to formula (a2-1-6) is preferred, and any one of formula (a2-1-1) to formula (a2-1-4) The structural unit represented is more preferable, and the structural unit represented by the formula (a2-1-1) or the formula (a2-1-3) is more preferable.

  When the resin (A) contains a structural unit (a2) having an alcoholic hydroxy group, the content is usually 1 to 45 mol%, preferably 1 to 45 mol% with respect to all the structural units of the resin (A). It is 40 mol%, More preferably, it is 1-35 mol%, More preferably, it is 2-20 mol%.

<Structural unit (a3)>
The lactone ring of the structural unit (a3) may be a monocycle such as a β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, or a condensed ring of a monocyclic lactone ring and another ring. However, the lactone ring is preferably a γ-butyrolactone ring, an adamantane lactone ring, or a bridged ring containing a γ-butyrolactone ring structure.

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). Resin (A) may contain these 1 type individually, and may contain 2 or more types.
[In Formula (a3-1), Formula (a3-2), Formula (a3-3) and Formula (a3-4),
L ^a4 , L ^a5 and L ^a6 each represent a group represented by —O— or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). .
L ^a7 is —O—, ^* —O—L ^a8 —O—, ^* —O—L ^a8 —CO—O—, ^* —O—L ^a8 —CO—O—L ^a9 —CO—O— or ^* —O—L ^a8 —O—CO—L ^a9 —O— is represented.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
* Represents a bond with a carbonyl group.
R ^a18 , R ^a19 and R ^a20 each 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.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
R ^a22 , R ^a23 and R ^a25 represent a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents any integer of 0 to 5.
q1 represents any integer of 0 to 3.
r1 represents any integer of 0 to 3.
w1 represents an integer of 0 to 8.
When p1, q1, r1, and / or w1 is 2 or more, a plurality of R ^a21 , R ^a22 , R ^a23 and / or R ^a25 may be the same as or different from each other. ]

Examples of the aliphatic hydrocarbon group for R ^a21 , R ^a22 and R ^a23 include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group and tert-butyl group. Can be mentioned.
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, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group. An alkyl group having 1 to 4 carbon atoms is preferable, and a methyl group or an ethyl group is more preferable.
Examples of the alkyl group having a halogen atom of Ra ²⁴ include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group, perfluoro A hexyl group, a trichloromethyl group, a tribromomethyl group, a triiodomethyl group, etc. are mentioned.

^Examples of the alkanediyl group of L ^a8 and L ^a9 include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, and a pentane-1,5. -Diyl group, hexane-1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1, 4-diyl group, 2-methylbutane-1,4-diyl group, etc. are mentioned.

In formula (a3-1) to formula (a3-4), L ^{a4 to} L ^a6 are preferably each independently —O— or k— is an integer of 1 to 4 —O— ( CH ₂ ) _{k 3} —CO—O—, more preferably —O— and * —O—CH ₂ —CO—O—, and still more preferably an oxygen atom.
L ^a7 is preferably —O— or ^* —O—L ^a8 —CO—O—, more preferably —O—, —O—CH ₂ —CO—O— or —O—C ₂ H ₄ —. CO-O-.
R ^{a18 to} R ^a21 are preferably methyl groups.
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 still more preferably a hydrogen atom or a methyl group.
R ^a22 , R ^a23 and R ^a25 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1, q1, r1 and w1 are each independently preferably an integer of 0 to 2, more preferably 0 or 1.
In formula (a3-4), formula (a3-4) ′ is particularly preferred.
(Wherein R ^a24 and L ^a7 represent the same meaning as described above.)

As monomers for deriving the structural unit (a3), monomers described in JP 2010-204646 A, monomers described in JP 2000-122294 A, monomers described in JP 2012-41274 A are listed. Can be mentioned. As the structural unit (a3), a structural unit represented by any of the following is preferable, and the formula (a3-1-1), the formula (a3-2-1), the formula (a3-2-2), and the formula ( The structural unit represented by any one of a3-4-1) to formula (a3-4-6) is more preferable, and is represented by formula (a3-1-1), formula (a3-2-3), or formula (a3- The structural unit represented by 4-2) is more preferable.

In the structural unit, a compound in which a methyl group corresponding to R ^a18 , R ^a19 , R ^a20 and R ^a24 is replaced with a hydrogen atom is also a specific example of the structural unit (a3).

When the resin (A) includes the structural unit (a3), the total content is usually 5 to 70 mol%, preferably 10 to 65 mol%, based on all the structural units of the resin (A). More preferably, it is 10-60 mol%.
Each content rate of the structural unit represented by Formula (a3-1), Formula (a3-2), Formula (a3-3), and Formula (a3-4) is based on all structural units of the resin (A). Usually, it is 5 to 60 mol%, preferably 5 to 50 mol%, more preferably 10 to 50 mol%.

<Other structural units (t)>
The resin (A) may contain another structural unit (t) as a structural unit other than the structural unit (a1) and the structural unit (s). As the structural unit (t), in addition to the structural unit (a2) and the structural unit (a3), a structural unit having a halogen atom (hereinafter sometimes referred to as “structural unit (a4)”) and a non-leaving hydrocarbon group. And a structural unit that may be included (hereinafter sometimes referred to as “structural unit (a5)”).

<Structural unit (a4)>
The halogen atom in the structural unit (a4) is preferably a fluorine atom. As the structural unit (a4), a structural unit represented by formula (a4-0) can be given.
[In the formula (a4-0),
R ⁵⁵ represents a hydrogen atom or a methyl group.
L ⁵ represents a single bond or an aliphatic saturated hydrocarbon group having 1 to 4 carbon atoms.
L ³ represents a C 1-8 perfluoroalkanediyl group or a C 5-12 perfluorocycloalkanediyl group.
R ⁶ represents a hydrogen atom or a fluorine atom. ]

Examples of the aliphatic saturated hydrocarbon group for L ⁵ include an alkanediyl group having 1 to 4 carbon atoms, such as a methylene group, an ethylene group, a propane-1,3-diyl group, and a butane-1,4-diyl group. Having a side chain of an alkyl group (especially methyl group, ethyl group, etc.), ethane-1,1-diyl group, propane-1,2 -Branched alkanediyl groups such as diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.

The perfluoroalkanediyl group of L ³ includes a difluoromethylene group, a perfluoroethylene group, a perfluoropropane-1,1-diyl group, a perfluoropropane-1,3-diyl group, a perfluoropropane-1,2-diyl group, and a perfluoropropane. -2,2-diyl group, perfluorobutane-1,4-diyl group, perfluorobutane-2,2-diyl group, perfluorobutane-1,2-diyl group, perfluoropentane-1,5-diyl group, perfluoropentane -2,2-diyl group, perfluoropentane-3,3-diyl group, perfluorohexane-1,6-diyl group, perfluorohexane-2,2-diyl group, perfluorohexane-3,3-diyl group, perfluoroheptane -1,7-diyl group, perfluoroheptane 2,2-diyl group, perfluoroheptane-3,4-diyl group, perfluoroheptane-4,4-diyl group, perfluorooctane-1,8-diyl group, perfluorooctane-2,2-diyl group, perfluorooctane- Examples include 3,3-diyl group and perfluorooctane-4,4-diyl group.
Examples of the L ³ perfluorocycloalkanediyl group include a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, and a perfluoroadamantanediyl group.

L ⁵ is preferably a single bond, a methylene group or an ethylene group, more preferably a single bond or a methylene group.
L ³ is preferably a C 1-6 perfluoroalkanediyl group, and more preferably a C ^1-3 C perfluoroalkanediyl group.

Examples of the structural unit (a4-0) include the following.

In the above structural unit, a structural unit in which a methyl group corresponding to R ⁵ is replaced with a hydrogen atom can also be given as a specific example of the structural unit (a4-0).

As the structural unit (a4), a structural unit represented by formula (a4-1) can be given.
[In the formula (a4-1),
R ^a41 represents a hydrogen atom or a methyl group.
R ^a42 represents an ^optionally substituted hydrocarbon group having 1 to 20 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—. Good.
A ^a41 represents a ^C1-C6 alkanediyl group which may have a substituent 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 ^C 1-5 divalent aliphatic hydrocarbon group which may have a substituent.
A ^a43 represents a ^C 1-5 divalent aliphatic hydrocarbon group which may have a substituent or a single bond.
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 6 or less. ]
At least one of A ^a41 and R ^a42 is a group having a halogen atom as a substituent.
* And ** are bonds, and * is a bond with —O—CO—R ^a42 . ]
s is preferably 0.

^Examples of the hydrocarbon group for R ^a42 include chain and cyclic aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and groups formed by combining these. Examples of chain aliphatic hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, hexadecyl, pentadecyl, hexyldecyl And alkyl groups such as a heptadecyl group and an octadecyl group. Examples of the cyclic alicyclic hydrocarbon group include a cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group; a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups (* Represents a bond.) And a polycyclic alicyclic hydrocarbon group.
Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a biphenylyl group, a phenanthryl group, and a fluorenyl group.

The hydrocarbon group for R ^a42 is preferably a chain or cyclic aliphatic hydrocarbon group or a group formed by combining these. These groups may have a carbon-carbon unsaturated bond, but chain and cyclic aliphatic saturated hydrocarbon groups and groups formed by combining them are more preferable.

^Examples of the substituent for R ^a42 include a halogen atom and a group represented by the formula (a-g3). As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, Preferably a fluorine atom is mentioned.
[In the formula (a-g3),
X ^a43 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ^a45 represents a C ^1-17 aliphatic hydrocarbon group having at least one halogen atom.
* Represents a bond with a carbonyl group. ]

^As the aliphatic hydrocarbon group for A ^a45, the same groups as those exemplified for R ^a42 can be mentioned.
R ^a42 is preferably an aliphatic hydrocarbon group which may have a halogen atom, more preferably an alkyl group having a halogen atom and / or an aliphatic hydrocarbon group having a group represented by the formula (a-g3). .

When R ^a42 is an aliphatic hydrocarbon group having a halogen atom, it is preferably an aliphatic hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, and still more preferably a carbon number. It is a 1-6 perfluoroalkyl group, Most preferably, it is a C1-C3 perfluoroalkyl group. Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, and a perfluorooctyl group. Examples of the perfluorocycloalkyl group include a perfluorocyclohexyl group.

When R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula (a-g3), including the carbon number contained in the group represented by the formula (a-g3), the aliphatic hydrocarbon The total carbon number of the group is preferably 15 or less, more preferably 12 or less. When it has a group represented by the formula (a-g3) as a substituent, the number is preferably 1.

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

1-6 are preferable and, as for carbon number of the aliphatic hydrocarbon group of ^Aa46 , 1-3 are more preferable.
4-15 are preferable, as for carbon number of the aliphatic hydrocarbon group of ^Aa47 , 5-12 are more preferable, and a cyclohexyl group or an adamantyl group is further more preferable.

Examples of the group represented by the formula (a-g2) include the following groups.

^As the alkanediyl group of ^Aa41 , 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 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 include branched alkanediyl groups such as 2-methylbutane-1,4-diyl group.
^Examples of the substituent in the alkanediyl group of A ^a41 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
A ^a41 is preferably an alkanediyl group having 1 to 4 carbon atoms, more preferably an alkanediyl group having 2 to 4 carbon atoms, and still more preferably an ethylene group.

^Examples of the aliphatic hydrocarbon group represented by A ^a42 , A ^a43, and A ^{a44 in} the group represented by the formula (a-g1) (hereinafter sometimes referred to as “group (a-g1)”) include a methylene group and an ethylene group. Propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl Group, 2-methylpropane-1,2-diyl group and the like. Examples of these substituents include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.

^Examples of the group (a-g1) in which X ^a42 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group include the following groups. In the following examples, * and ** each represent a bond, and ** is a bond with —O—CO—R ^a42 .

As the structural unit represented by the formula (a4-1), structural units represented by the formula (a4-2) and the formula (a4-3) are preferable.
[In the formula (a4-2),
R ^f1 represents a hydrogen atom or a methyl group.
A ^f1 represents an alkanediyl group having 1 to 6 carbon atoms.
R ^f2 represents a C 1-10 hydrocarbon group having a fluorine atom. ]

As the alkanediyl group of A ^f1 , a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group , A straight-chain alkanediyl group such as hexane-1,6-diyl group; 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2 -Branched alkanediyl groups such as a diyl group, 1-methylbutane-1,4-diyl group, 2-methylbutane-1,4-diyl group.

The hydrocarbon group of R ^f2 includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group, and the aliphatic hydrocarbon group includes a chain, a cyclic group, and a group formed by a combination thereof. As the aliphatic hydrocarbon group, an alkyl group and an alicyclic hydrocarbon group are preferable.
Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group and 2 -An ethylhexyl group is mentioned.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon group includes a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a methylcyclohexyl group. And cycloalkyl groups such as dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, cycloheptyl group and cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, 2-alkyladamantan-2-yl group, 1- (adamantan-1-yl) alkane-1-yl group, norbornyl group, A methyl norbornyl group and an isobornyl group are mentioned.

Examples of the hydrocarbon group having a fluorine atom for R ^f2 include an alkyl group having a fluorine atom and an alicyclic hydrocarbon group having a fluorine atom.
Specifically, as the alkyl group having a fluorine atom, a difluoromethyl group, a trifluoromethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, Perfluoroethyl group, 1,1,2,2-tetrafluoropropyl group, 1,1,2,2,3,3-hexafluoropropyl group, perfluoroethylmethyl group, 1- (trifluoromethyl) -1,2 , 2,2-tetrafluoroethyl group, perfluoropropyl group, 1,1,2,2-tetrafluorobutyl group, 1,1,2,2,3,3-hexafluorobutyl group, 1,1,2, 2,3,3,4,4-octafluorobutyl group, perfluorobutyl group, 1,1-bis (trifluoro) methyl-2,2,2-trifluoroethyl group, 2- (perfluoro (Ropropyl) ethyl group, 1,1,2,2,3,3,4,4-octafluoropentyl group, perfluoropentyl group, 1,1,2,2,3,3,4,4,5,5- Decafluoropentyl group, 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, perfluoropentyl group, 2- (perfluorobutyl) ethyl group, 1,1,2, 2,3,3,4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyl group, perfluoropentyl Examples thereof include fluorinated alkyl groups such as a methyl group and a perfluorohexyl group.
Examples of the alicyclic hydrocarbon group having a fluorine atom include fluorinated cycloalkyl groups such as a perfluorocyclohexyl group and a perfluoroadamantyl group.

In Formula (a4-2), A ^f1 is preferably an alkanediyl group having 2 to 4 carbon atoms, and more preferably an ethylene group.
R ^f2 is preferably a fluorinated alkyl group having 1 to 6 carbon atoms.

[In the formula (a4-3),
R ^f11 represents a hydrogen atom or a methyl group.
A ^f11 represents an alkanediyl group having 1 to 6 carbon atoms.
A ^f13 represents an aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a fluorine atom.
X ^f12 represents a carbonyloxy group or an oxycarbonyl group.
A ^f14 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a fluorine atom. However, at least one of A ^f13 and A ^f14 represents an aliphatic hydrocarbon group having a fluorine atom. ]

^Examples of the alkanediyl group for A ^f11 include the same groups as the alkanediyl group for A ^f1 .

The aliphatic hydrocarbon group for A ^f13 includes either a chain or a cyclic group, and a divalent aliphatic hydrocarbon group formed by combining them. The aliphatic hydrocarbon may have a carbon-carbon unsaturated bond, but is preferably a saturated aliphatic hydrocarbon group.
The aliphatic hydrocarbon group which may have a fluorine atom of A ^f13 is preferably an aliphatic saturated hydrocarbon group which may have a fluorine atom, and more preferably a perfluoroalkanediyl group.
Examples of the divalent chain aliphatic hydrocarbon group which may have a fluorine atom include alkanediyl groups such as methylene group, ethylene group, propanediyl group, butanediyl group and pentanediyl group; difluoromethylene group, perfluoroethylene Groups, perfluoroalkanediyl groups such as perfluoropropanediyl group, perfluorobutanediyl group and perfluoropentanediyl group.
The divalent cyclic aliphatic hydrocarbon group which may have a fluorine atom may be either monocyclic or polycyclic. Examples of the monocyclic aliphatic hydrocarbon group include a cyclohexanediyl group and a perfluorocyclohexanediyl group. Examples of the polycyclic divalent aliphatic hydrocarbon group include an adamantanediyl group, a norbornanediyl group, a perfluoroadamantanediyl group, and the like.

As the aliphatic hydrocarbon group for A ^f14 , one of a chain type and a cyclic type, and an aliphatic hydrocarbon group formed by combining them are included. The aliphatic hydrocarbon may have a carbon-carbon unsaturated bond, but is preferably a saturated aliphatic hydrocarbon group.
The aliphatic hydrocarbon group which may have a fluorine atom for A ^f14 is preferably an aliphatic saturated hydrocarbon group which may have a fluorine atom.
Examples of the chain aliphatic hydrocarbon group which may have a fluorine atom include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 1,1,1-trifluoroethyl group, 1,1 , 2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 1,1,1,2,2-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3 , 4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 1,1,1,2,2,3,3,4,4-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group, A heptyl group, a perfluoro heptyl group, an octyl group, a perfluorooctyl group, etc. are mentioned.
The cyclic aliphatic hydrocarbon group which may have a fluorine atom may be monocyclic or polycyclic. Examples of the group containing a monocyclic aliphatic hydrocarbon group include a cyclopropylmethyl group, a cyclopropyl group, a cyclobutylmethyl group, a cyclopentyl group, a cyclohexyl group, and a perfluorocyclohexyl group. Examples of the group containing a polycyclic aliphatic hydrocarbon group include an adamantyl group, an adamantylmethyl group, a norbornyl group, a norbornylmethyl group, a perfluoroadamantyl group, and a perfluoroadamantylmethyl group.

In the formula ^(a4-3), examples of ^{A f11,} ethylene group is preferable.
The aliphatic hydrocarbon group for A ^f13 preferably has 1 to 6 carbon atoms, more preferably 2 to 3 carbon atoms.
The aliphatic hydrocarbon group for A ^f14 preferably has 3 to 12 carbon atoms, and more preferably 3 to 10 carbon atoms. 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.

As the structural unit represented by the formula (a4-2), a structural unit represented by the formula (a4-1-1) to the formula (a4-1-11) and a methyl group corresponding to R ^f1 can be a hydrogen atom. Examples include structural units that have been replaced.

The structural unit represented by formula (a4-3), include structural units in which a methyl group is replaced by a hydrogen atom corresponding to the structural units and R ^f11 below.

Examples of the structural unit (a4) include the structural units described below.

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

<Structural unit (a5)>
Examples of the non-leaving hydrocarbon group that the structural unit (a5) has include a linear, branched, or cyclic hydrocarbon group, and a group having an alicyclic hydrocarbon group is preferable. As a structural unit (a5), the structural unit represented by a formula (a5-1) is mentioned, for example.
[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 a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms. . However, the hydrogen atom bonded to the carbon atom at the coupling position with the L ⁵⁵ is not 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, a methylene group contained in the saturated hydrocarbon group may be replaced by an oxygen atom or a carbonyl group. ]

The alicyclic hydrocarbon group for R ⁵² may be 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 a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. , Alkyl groups such as octyl group and 2-ethylhexyl group.
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 aliphatic saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, preferably a divalent aliphatic saturated hydrocarbon group. .
Examples of the divalent aliphatic saturated hydrocarbon group include alkanediyl groups such as a methylene group, an ethylene group, a propanediyl group, a butanediyl group, and a pentanediyl group.
The divalent alicyclic saturated hydrocarbon group may be 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 the methylene group contained in the saturated hydrocarbon group is replaced with an oxygen atom or a carbonyl group include groups represented by formulas (L1-1) to (L1-4). In the following formula, * represents a bond with an oxygen atom.
In formula (L1-1),
X ^x1 represents a carbonyloxy group or an oxycarbonyl group.
L ^x1 represents a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
L ^x2 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
However, the total carbon number of L ^x1 and L ^x2 is 16 or less.
In formula (L1-2),
L ^x3 represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms.
L ^x4 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
However, the total carbon number of L ^x1 and L ^x2 is 17 or less.
In formula (L1-3),
L ^x5 represents a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^x6 and L ^x7 each independently represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms.
However, the total carbon number of L ^x5 , L ^x6 and L ^x7 is 15 or less.
In formula (L1-4),
L ^x8 and L ^x9 each independently 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 C 1-8 divalent aliphatic saturated hydrocarbon group, more preferably a methylene group or an ethylene group.
L ^x2 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond.
L ^x3 is preferably a C 1-8 divalent aliphatic saturated hydrocarbon group.
L ^x4 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x5 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group.
L ^x6 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group.
L ^x7 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^x8 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond or a methylene group.
L ^x9 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a single bond or a methylene group.
W ^x1 is preferably a divalent alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms, more preferably a cyclohexanediyl group or an adamantanediyl group.

As group represented by a formula (L1-1), the bivalent group shown below is mentioned, for example.

As group represented by a formula (L1-2), the bivalent group shown below is mentioned, for example.

As group represented by a formula (L1-3), the bivalent group shown below is mentioned, for example.

As group represented by a formula (L1-4), the bivalent group shown below is mentioned, for example.

^L55 is preferably a single bond, a methylene group, an ethylene group or a group represented by the formula (L1-1), more preferably a single bond or a group represented by the formula (L1-1). .

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

  When the resin (A) has the structural unit (a5), the content is preferably 1 to 30 mol%, more preferably 2 to 20 mol%, based on all structural units of the resin (A). More preferred is ˜15 mol%.

The resin (A) is preferably a resin composed of the structural unit (a1) and the structural unit (s), that is, a copolymer of the monomer (a1) and the monomer (s).
The structural unit (s) is preferably at least one of the structural unit (a2) and the structural unit (a3). The structural unit (a2) is preferably a structural unit represented by the formula (a2-1). The structural unit (a3) is preferably a structural unit represented by formula (a3-1-1) to formula (a3-1-4), formula (a3-2-1) to formula (a3-2-4). And at least one selected from structural units represented by formula (a3-4-1) to formula (a3-4-2).

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 derives these structural units. can do. The content rate of each structural unit which resin (A) has can be adjusted with the usage-amount of the monomer used for superposition | polymerization.
The weight average molecular weight of the resin (A) is preferably 2,000 or more (more preferably 2,500 or more, more preferably 3,000 or more), 50,000 or less (more preferably 30,000 or less, further preferably 15,000 or less). In the present specification, the weight average molecular weight is a value obtained by gel permeation chromatography under the conditions described in Examples.

<Resin other than resin (A)>
The resist composition of the present invention may contain a resin other than the resin (A). Examples of such a resin include a resin containing the structural unit (t), and a resin containing the structural unit (a4) (however, the structural unit (a1) is not included. Hereinafter, the case of “resin (X)”) Is preferred).
In the resin (X), the content of the structural unit (a4) is preferably 40 mol% or more, more preferably 45 mol% or more, and still more preferably 50 mol% or more with respect to all the structural units of the resin (X). .
Examples of the structural unit that the resin (X) may further include a structural unit derived from the structural unit (a2), the structural unit (a3), and other known monomers.
The weight average molecular weight of the resin (X) is preferably 8,000 or more (more preferably 10,000 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 with respect to 100 parts by mass of the resin (A). Preferably it is 1-40 mass parts, Most preferably, it is 2-30 mass parts.

  As for the total content rate of resin other than resin (A) and resin (A), 80 to 99 mass% is preferable with respect to solid content of a 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.

<Acid generator (B)>
As the acid generator (B), a known acid generator can be used, and either an ionic acid generator or a nonionic generator may be used. Preferably, it is an ionic acid generator. Examples of the ionic acid generator include an ionic acid generator composed of a combination of a known cation and a known anion.

Examples of the acid generator (B) include organic sulfonic acids, organic sulfonium salts, and the like. For example, acid generation described in JP2013-68914A, JP2013-3155A, and JP2013-11905A Agents and the like. Specific examples include those represented by formula (B1-1) to formula (B1-48), respectively, among which formula (B1-1) to formula (B1-3), formula (B) containing an arylsulfonium cation B1-5) to formula (B1-7), formula (B1-11) to formula (B1-14), formula (B1-17), formula (B1-20) to formula (B1-26), formula (B1) -29) and those represented by formulas (B1-31) to (B1-48) are particularly preferred.

An acid generator (B) may contain 2 or more types.
The resist composition may contain only the salt (I) or a combination of the salt (I) and the acid generator (B).
When the salt (I) and the acid generator (B) are contained as the acid generator, the ratio of the content of the salt (I) and the acid generator (B) (mass ratio, salt (I0): acid generator (B)) is usually 1:99 to 99: 1, preferably 2:98 to 98: 2, more preferably 5:95 to 95: 5.
In the resist composition, when the salt (I) and the acid generator (B) are used as the acid generator, the content of the salt (I) and the acid generator (B) is preferably relative to the resin (A). Is 1% by mass or more (more preferably 3% by mass or more), preferably 40% by mass or less (more preferably 35% by mass or less).

<Solvent (E)>
In the resist composition, the content of the solvent (E) is usually 90% by mass or more, preferably 92% by mass or more, more preferably 94% by mass or more, and 99.9% by mass or less. Preferably it is 99 mass% or less. The content rate of a solvent (E) can be measured by well-known analysis means, such as a liquid chromatography or a gas chromatography, for example.

  Examples of the solvent (E) include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate; glycol ethers such as propylene glycol monomethyl ether; ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate Esters such as acetone, methyl isobutyl ketone, ketones such as 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; and the like. One kind of the solvent (E) may be contained alone, or two or more kinds may be contained.

<Quencher (C)>
Examples of the quencher (C) include a salt that generates an acid having a lower acidity than an acid generated from a basic nitrogen-containing organic compound or an acid generator.
Examples of the basic nitrogen-containing organic compound include amines and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines.

  Examples of the amine include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N-dimethylaniline, diphenylamine, hexylamine, Heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, tri Heptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, Rudicyclohexylamine, 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- Tyrimidazole, pyridine, 4-methylpyridine, 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,2-di (2-pyridyl) ethene, 1,2- Di (4-pyridyl) ethene, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyloxy) ethane, di (2-pyridyl) ketone, 4,4′-dipyridyl sulfide, 4 , 4'-dipyridyl disulfide, 2,2'-dipyridylamine, 2,2'-dipicolylamine, bipyridine, etc., preferably diisopropylaniline, more preferably 2,6-diisopropylaniline. .

  As ammonium salts, tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3- (trifluoromethyl) phenyltrimethyl Ammonium hydroxide, tetra-n-butylammonium salicylate, choline and the like can be mentioned.

The acidity in a salt that generates an acid having a weaker acidity than the acid generated from the salt (aa) and the acid generator (B) is represented by an acid dissociation constant (pKa). The salt that generates an acid having a lower acidity than the acid generated from the salt (aa) and the acid generator (B) is a salt in which the acid dissociation constant of the acid generated from the salt is usually −3 <pKa, A salt of −1 <pKa <7 is preferable, and a salt of 0 <pKa <5 is more preferable.
Examples of the salt that generates an acid having a lower acidity than the acid generated from the salt (aa) and the acid generator (B) include a salt represented by the following formula and a salt represented by the formula (D) (hereinafter, weak acid). And may be referred to as an intramolecular salt (D)), and JP 2012-229206 A, JP 2012-6908 A, JP 2012-72109 A, JP 2011-39502 A, and JP 2011-191745 A. And salts described in Japanese Patent Publication. Preferably, it is a weak acid salt represented by the formula (D).

  The content of the quencher (C) is preferably about 0.01 to 5% by mass based on the solid content of the resist composition.

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

<Preparation of resist composition>
The resist composition of the present invention comprises a resin (A), a salt (I) of the present invention, a resin other than the resin (A) used as necessary, an acid generator (B), a solvent (E), a quencher. It can be prepared by mixing a salt that generates a weakly acidic acid such as char (C) or weak acid inner salt (D) and other component (F). The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select an appropriate temperature from 10-40 degreeC according to the kind etc. of resin etc., the solubility with respect to solvents (E), such as resin. An appropriate mixing time can be selected from 0.5 to 24 hours depending on the mixing temperature. The mixing means is not particularly limited, and stirring and mixing can be used.
After mixing each component, it is preferable to filter using a filter having a pore size of about 0.003 to 0.2 μm.

<Method for producing resist pattern>
The method for producing a resist pattern of the present invention comprises:
(1) The process of apply | coating the resist composition of this invention on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.

  The resist composition can be applied onto the substrate by a commonly used apparatus such as a spin coater. Examples of the substrate include an inorganic substrate such as a silicon wafer. Before applying the resist composition, the substrate may be washed, or an antireflection film or the like may be formed on the substrate.

By drying the composition after coating, the solvent is removed and a composition layer is formed. Drying is performed, for example, by evaporating the solvent using a heating device such as a hot plate (so-called pre-baking), or using a decompression device. The heating temperature is preferably 50 to 200 ° C., and the heating time is preferably 10 to 180 seconds. Moreover, it is preferable that the pressure at the time of drying under reduced pressure is about 1-1.0 * 10 < ⁵ > Pa.

The obtained composition layer is usually exposed using an exposure machine. The exposure machine may be an immersion exposure machine. Exposure light sources include those that emit laser light in the ultraviolet region such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), solid-state laser light source (YAG or semiconductor laser) Etc.) Using various lasers such as those that convert wavelength of laser light from the laser and emit harmonic laser light in the far-ultraviolet region or vacuum ultraviolet region, those that irradiate electron beams or extreme ultraviolet light (EUV), etc. Can do. In this specification, the irradiation of these radiations may be collectively referred to as “exposure”. At the time of exposure, exposure is usually performed through a mask corresponding to a required pattern. When the exposure light source is an electron beam, exposure may be performed by direct drawing without using a mask.

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

  The heated composition layer is usually developed using a developer using a developing device. Examples of the developing method include a dipping method, a paddle method, a spray method, and a dynamic dispensing method. The development temperature is preferably 5 to 60 ° C., for example, and the development time is preferably 5 to 300 seconds, for example. A positive resist pattern or a negative resist pattern can be produced by selecting the type of developer as follows.

When producing a positive resist pattern from the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer may be 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 alkali developer may contain a surfactant.
It is preferable to wash the resist pattern with ultrapure water after development, and then remove the water remaining on the substrate and the pattern.

In the case of producing a negative resist pattern from the resist composition of the present invention, a developer containing an organic solvent as a developer (hereinafter sometimes referred to as “organic developer”) is used.
Organic solvents contained in the organic developer include ketone solvents such as 2-hexanone and 2-heptanone; glycol ether ester solvents such as propylene glycol monomethyl ether acetate; ester solvents such as butyl acetate; glycols such as propylene glycol monomethyl ether Examples include ether solvents; amide solvents such as N, N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole.
In the organic developer, the content of the organic solvent is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and still more preferably only the organic solvent.
Among them, the organic developer is preferably a developer containing butyl acetate and / or 2-heptanone. In the organic developer, the total content of butyl acetate and 2-heptanone is preferably 50% by mass to 100% by mass, more preferably 90% by mass to 100% by mass, and substantially butyl acetate and / or 2 -More preferred is heptanone alone.
The organic developer may contain a surfactant. The organic developer may contain a trace amount of water.
At the time of development, the development may be stopped by substituting a solvent of a different type from the organic developer.

It is preferable to wash the developed resist pattern with a rinse solution. The rinsing liquid is not particularly limited as long as it does not dissolve the resist pattern, and a solution containing a general organic solvent can be used, and an alcohol solvent or an ester solvent is preferable.
After the cleaning, it is preferable to remove the rinse solution remaining on the substrate and the pattern.

<Application>
The resist composition of the present invention is suitable as a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure, or a resist composition for EUV exposure. Yes, it is more suitable as a resist composition for ArF excimer laser 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 “parts” representing the content or amount used are based on mass unless otherwise specified.
The weight average molecular weight is a value determined by gel permeation chromatography. The analysis conditions for gel permeation chromatography are as follows.
Column: TSKgel Multipore HXL-M x 3 + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)
The structure of the compound was confirmed by measuring the molecular peak using mass spectrometry (LC is model 1100 manufactured by Agilent, and MASS is LC / MSD manufactured by Agilent). In the following examples, the value of this molecular ion peak is indicated by “MASS”.

Example 1: Synthesis of a salt represented by the formula (I-3)
10.6 parts of the compound represented by the formula (I-3-a), 9.6 parts of the salt represented by the formula (I-3-b) and 50 parts of acetonitrile were mixed and stirred at 23 ° C. for 30 minutes. . To the obtained mixed solution, 5 parts of N-methylpyrrolidine was added dropwise over 5 minutes, followed by stirring at 23 ° C. for 18 hours. To the resulting reaction solution, 35 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Thereafter, 75 parts of chloroform was added and stirred, and the organic layer was recovered by liquid separation. To the collected organic layer, 70 parts of 5% aqueous sodium hydrogen carbonate solution was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. To the collected organic layer, 70 parts of ion-exchanged water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This operation was repeated three times. The recovered organic layer was concentrated to obtain 12.47 parts of the salt represented by the formula (I-3-c).

2.7 parts of the salt represented by the formula (I-3-d), 16 parts of ion-exchanged water and 24 parts of acetonitrile were mixed and stirred at 23 ° C. for 1 hour. To the obtained mixed solution, 6.2 parts of the salt represented by the formula (I-3-c), 6.2 parts of ion-exchanged water, and 12.4 parts of acetonitrile were mixed and stirred at 23 ° C. for 36 hours. The obtained reaction product was concentrated, 80 parts of chloroform and 30 parts of ion-exchanged water were added to the concentration residue, and the mixture was stirred at 23 ° C. for 30 minutes and separated to take out the organic layer. To the collected organic layer, 30 parts of ion-exchanged water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This operation was repeated three times. The recovered organic layer was concentrated to obtain 6.58 parts of the salt represented by the formula (I-3-e).

2.85 parts of a salt represented by the formula (I-3-e), 0.46 parts of a compound represented by the formula (I-3-f) and 20 parts of monochlorobenzene were charged and stirred at 23 ° C. for 30 minutes. . To the obtained mixture, 0.02 part of copper (II) dibenzoate was added, and the mixture was further stirred at 100 ° C. for 30 minutes. The resulting reaction solution was concentrated. To the obtained residue, 35 parts of chloroform, 12 parts of ion exchange water and 0.15 part of 28% ammonia water were added and stirred at 23 ° C. for 30 minutes, followed by liquid separation to take out the organic layer. To the recovered organic layer, 12 parts of ion exchange water was added and stirred at 23 ° C. for 30 minutes, followed by liquid separation to take out the organic layer. This washing operation was repeated three times. After concentrating the obtained organic layer, 30 parts of tert-butyl methyl ether was added to the resulting residue and stirred, followed by filtration to obtain 1.38 parts of the salt represented by the formula (I-3). Got.
MASS (ESI (+) Spectrum): M ⁺ 359.2
MASS (ESI (-) Spectrum): M ^- 323.0

Example 2: Synthesis of a salt represented by the formula (I-2)
2.9 parts of the salt represented by the formula (I-2-d), 16 parts of ion-exchanged water and 24 parts of acetonitrile were mixed and stirred at 23 ° C. for 1 hour. To the obtained mixed solution, 6.2 parts of the salt represented by the formula (I-3-c), 6.2 parts of ion-exchanged water, and 12.4 parts of acetonitrile were mixed and stirred at 23 ° C. for 36 hours. The obtained reaction product was concentrated, and 80 parts of chloroform and 30 parts of ion-exchanged water were added to the concentrated residue, followed by stirring at 23 ° C. for 30 minutes, followed by liquid separation to take out the organic layer. To the collected organic layer, 30 parts of ion-exchanged water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This operation was repeated three times. The recovered organic layer was concentrated to obtain 6.44 parts of the salt represented by the formula (I-2-e).

2.9 parts of a salt represented by the formula (I-2-e), 0.5 part of a compound represented by the formula (I-3-f) and 20 parts of monochlorobenzene were charged and stirred at 23 ° C. for 30 minutes. . To the obtained mixture, 0.02 part of copper (II) dibenzoate was added, and the mixture was further stirred at 100 ° C. for 30 minutes. The resulting reaction solution was concentrated. To the obtained residue, 35 parts of chloroform, 12 parts of ion-exchanged water and 0.15 part of 28% ammonia water were added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. To the recovered organic layer, 12 parts of ion exchange water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This washing operation was repeated three times. The obtained organic layer was concentrated. To the obtained residue, 30 parts of tert-butyl methyl ether was added and stirred, followed by filtration to obtain 1.12 parts of the salt represented by the formula (I-2).
MASS (ESI (+) Spectrum): M ⁺ 359.2
MASS (ESI (−) Spectrum): M ^- 339.1

Example 3: Synthesis of salt represented by formula (I-13)
2.7 parts of a salt represented by the formula (I-13-d), 16 parts of ion exchange water and 24 parts of acetonitrile were charged and stirred at 23 ° C. for 1 hour. To the obtained mixed solution, 6.2 parts of the salt represented by the formula (I-3-c), 6.2 parts of ion-exchanged water, and 12.4 parts of acetonitrile were mixed and stirred at 23 ° C. for 36 hours. The obtained reaction product was concentrated, and 80 parts of chloroform and 30 parts of ion-exchanged water were added to the concentrated residue, followed by stirring at 23 ° C. for 30 minutes, followed by liquid separation to take out the organic layer. To the collected organic layer, 30 parts of ion-exchanged water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This operation was repeated three times. The recovered organic layer was concentrated to obtain 6.44 parts of the salt represented by the formula (I-13-e).

2.9 parts of the salt represented by the formula (I-13-e), 0.5 part of the compound represented by the formula (I-3-f) and 20 parts of monochlorobenzene were mixed and stirred at 23 ° C. for 30 minutes. did. To the obtained mixture, 0.02 part of copper (II) dibenzoate was added, and the mixture was further stirred at 100 ° C. for 30 minutes. The obtained reaction solution is concentrated, and 35 parts of chloroform, 12 parts of ion-exchanged water and 0.15 part of 28% aqueous ammonia are added to the resulting residue, and the mixture is stirred at 23 ° C. for 30 minutes, followed by liquid separation. Was taken out. To the recovered organic layer, 12 parts of ion exchange water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This washing operation was repeated three times. The obtained organic layer was concentrated. To the obtained residue, 30 parts of tert-butyl methyl ether was added and stirred, followed by filtration to obtain 1.88 parts of the salt represented by the formula (I-13).
MASS (ESI (+) Spectrum): M ⁺ 359.2
MASS (ESI (-) Spectrum): M ^- 323.1

Example 4: Synthesis of salt represented by formula (I-131)
11.5 parts of the compound represented by the formula (I-131-a), 9.6 parts of the salt represented by the formula (I-3-b) and 50 parts of acetonitrile were mixed and stirred at 23 ° C. for 30 minutes. . To the obtained mixed solution, 5 parts of N-methylpyrrolidine was added dropwise over 5 minutes, followed by stirring at 23 ° C. for 18 hours. To the resulting reaction solution, 35 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Thereafter, 75 parts of chloroform was added and stirred, and the organic layer was recovered by liquid separation. To the collected organic layer, 70 parts of 5% aqueous sodium hydrogen carbonate solution was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. To the collected organic layer, 70 parts of ion-exchanged water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This operation was repeated three times. The recovered organic layer was concentrated to obtain 11.22 parts of the salt represented by the formula (I-131-c).

2.7 parts of the salt represented by the formula (I-3-d), 16 parts of ion-exchanged water and 24 parts of acetonitrile were mixed and stirred at 23 ° C. for 1 hour. To the obtained mixed solution, 6.5 parts of the salt represented by the formula (I-131-c), 6.5 parts of ion-exchanged water and 13 parts of acetonitrile were mixed and stirred at 23 ° C. for 36 hours. The obtained reaction product was concentrated, 80 parts of chloroform and 30 parts of ion-exchanged water were added to the concentration residue, and the mixture was stirred at 23 ° C. for 30 minutes and separated to take out the organic layer. To the collected organic layer, 30 parts of ion-exchanged water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This operation was repeated three times. The recovered organic layer was concentrated to obtain 6.28 parts of the salt represented by the formula (I-131-e).

2.94 parts of a salt represented by the formula (I-131-e), 0.46 part of a compound represented by the formula (I-3-f) and 20 parts of monochlorobenzene were charged and stirred at 23 ° C. for 30 minutes. . To the obtained mixture, 0.02 part of copper (II) dibenzoate was added, and the mixture was further stirred at 100 ° C. for 30 minutes. The resulting reaction solution was concentrated. To the obtained residue, 35 parts of chloroform, 12 parts of ion exchange water and 0.15 part of 28% ammonia water were added and stirred at 23 ° C. for 30 minutes, followed by liquid separation to take out the organic layer. To the recovered organic layer, 12 parts of ion exchange water was added and stirred at 23 ° C. for 30 minutes, followed by liquid separation to take out the organic layer. This washing operation was repeated three times. After concentrating the obtained organic layer, 30 parts of tert-butyl methyl ether was added to the resulting residue and stirred, followed by filtration to obtain 1.29 parts of the salt represented by the formula (I-131). Got.
MASS (ESI (+) Spectrum): M ⁺ 375.2
MASS (ESI (-) Spectrum): M ^- 323.0

Example 5: Synthesis of salt represented by formula (I-130)
2.9 parts of the salt represented by the formula (I-2-d), 16 parts of ion-exchanged water and 24 parts of acetonitrile were mixed and stirred at 23 ° C. for 1 hour. To the obtained mixed solution, 6.5 parts of the salt represented by the formula (I-131-c), 6.5 parts of ion-exchanged water and 13 parts of acetonitrile were mixed and stirred at 23 ° C. for 36 hours. The obtained reaction product was concentrated, and 80 parts of chloroform and 30 parts of ion-exchanged water were added to the concentrated residue, followed by stirring at 23 ° C. for 30 minutes, followed by liquid separation to take out the organic layer. To the collected organic layer, 30 parts of ion-exchanged water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This operation was repeated three times. The recovered organic layer was concentrated to obtain 6.23 parts of the salt represented by the formula (I-130-e).

3.0 parts of a salt represented by the formula (I-130-e), 0.5 part of a compound represented by the formula (I-3-f) and 20 parts of monochlorobenzene were charged and stirred at 23 ° C. for 30 minutes. . To the obtained mixture, 0.02 part of copper (II) dibenzoate was added, and the mixture was further stirred at 100 ° C. for 30 minutes. The resulting reaction solution was concentrated. To the obtained residue, 35 parts of chloroform, 12 parts of ion-exchanged water and 0.15 part of 28% ammonia water were added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. To the recovered organic layer, 12 parts of ion exchange water was added, stirred at 23 ° C. for 30 minutes, and separated to take out the organic layer. This washing operation was repeated three times. The obtained organic layer was concentrated. To the obtained residue, 30 parts of tert-butyl methyl ether was added and stirred, and then filtered to obtain 1.01 part of a salt represented by the formula (I-130).
MASS (ESI (+) Spectrum): M ⁺ 375.2
MASS (ESI (−) Spectrum): M ^- 339.1

Synthesis of Resin (A) The compound (monomer) used for the synthesis of resin (A) is shown below. Hereinafter, these compounds are referred to as “monomer (a1-1-3)” or the like according to the formula number.

Synthesis Example 1 [Synthesis of Resin A1]
Monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-1) and monomer (a3-4-2) are mixed in a molar ratio [monomer (a1-1-3): Monomer (a1-2-9): monomer (a2-1-1): monomer (a3-4-2)] is mixed to be 35: 15: 2.5: 47.5. 1.5 mass times propylene glycol monomethyl ether acetate was added to prepare a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and these were heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The obtained resin was added to a methanol / water mixed solvent, repulped, and then subjected to a purification operation of filtering twice to obtain a resin A1 having a weight average molecular weight of 8.0 × 10 ^{3 in} a yield of 69%. This resin A1 has the following structural units.

Synthesis Example 2 [Synthesis of Resin A2]
As the monomer, a monomer (a1-1-3), a monomer (a1-2-11), a monomer (a2-1-1) and a monomer (a3-4-2) are used, and the molar ratio [monomer (a1-1 -3): Monomer (a1-2-11): Monomer (a2-1-1): Monomer (a3-4-2)] except for mixing to be 35: 15: 2.5: 47.5 In the same manner as in Synthesis Example 1, a resin A2 having a weight average molecular weight of 7.9 × 10 ³ was obtained in a yield of 65%. This resin A2 has the following structural units.

Synthesis Example 3 [Synthesis of Resin X1]
Monomer (a4-1-7) was used as a monomer, and 1.5 mass times of methyl isobutyl ketone as the total monomer amount was added to prepare a solution. Azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the solution in an amount of 0.7 mol% and 2.1 mol%, respectively, with respect to the total monomer amount, and these were added at 75 ° C. Heated for about 5 hours. The obtained reaction mixture was poured into a large amount of a methanol / water mixed solvent to precipitate a resin, and this resin was filtered to obtain a resin X1 having a weight average molecular weight of 1.8 × 10 ^{4 in} a yield of 77%. This resin X1 has the following structural units.

Synthesis Example 4 [Synthesis of Resin X2]
Monomer (a5-1-1) and monomer (a4-0-12) are mixed so that the molar ratio [monomer (a5-1-1): monomer (a4-0-12)] is 50:50. Then, 1.2 mass times the total monomer amount of methyl isobutyl ketone was added to make a solution. To this solution, 3 mol% of azobis (2,4-dimethylvaleronitrile) as an initiator was added based on the total amount of monomers, and heated at 70 ° C. for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate a resin, and this resin was filtered to obtain a resin X2 (copolymer) having a weight average molecular weight of 1.0 × 10 ^{4 in} a yield of 91%. Got in. This resin X2 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, A2, X1, X2: Resin A1, Resin A2, Resin X1, Resin X2
<Acid generator>
I-2: salt represented by formula (I-2) I-3: salt represented by formula (I-3) I-13: salt represented by formula (I-13) I-130: formula Salt represented by (I-130) I-131: Salt represented by formula (I-131) B1-21: (Synthesis according to Examples of JP 2012-224611 A)
B1-22: (Synthesis according to the example of JP2012-224611)
B1-X1: (Synthesis according to the example of JP2011-081044A)
B1-X2: (Synthesis according to the examples of JP 2014-199389 A)
<Quencher (C)>
D1: (Tokyo Chemical Industry Co., Ltd.)
<Solvent>
Propylene glycol monomethyl ether acetate 265 parts Propylene glycol monomethyl ether 20 parts 2-heptanone 20 parts γ-butyrolactone 3.5 parts

<Manufacture of resist pattern and its evaluation>
An organic antireflective coating composition (ARC-29; manufactured by Nissan Chemical Co., Ltd.) is applied to a silicon wafer and baked at 205 ° C. for 60 seconds to form an organic reflective film having a thickness of 78 nm on the wafer. A prevention film was formed. Next, on the organic antireflection film, the above resist composition was applied (spin coated) so that the film thickness after drying was 85 nm. After coating, the silicon wafer was pre-baked on a direct hot plate at the temperature described in the “PB” column of Table 2 for 60 seconds to form a composition layer. ArF excimer stepper for immersion exposure (XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light) on a silicon wafer on which the composition layer is formed, and a contact hole pattern (hole pitch 90 nm) Using a mask for forming a hole diameter of 55 nm), the exposure amount was changed stepwise. Note that ultrapure water was used as the immersion medium.
After the exposure, post-exposure baking was performed for 60 seconds on the hot plate at the temperature described in the “PEB” column of Table 2. Next, the composition layer on the silicon wafer is developed by using a butyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a developing solution by a dynamic dispensing method at 23 ° C. for 20 seconds, thereby forming a negative resist pattern. Manufactured.

  In the resist pattern obtained after development, the exposure amount at which the hole diameter formed using the mask was 45 nm was defined as the effective sensitivity.

<Evaluation of mask error factor (MEF)>
In terms of effective sensitivity, a resist pattern was formed using masks having mask hole diameters (hole diameters of light transmitting portions of the mask) of 57 nm, 56 nm, 55 nm, 54 nm, and 53 nm (all hole pitches were 90 nm). The slope of the regression line when the mask hole diameter was plotted on the horizontal axis and the hole diameter of the resist pattern formed (transferred) on the substrate by exposure was plotted on the vertical axis was calculated as the MEF value.
When the MEF value is 4.8 or less, the MEF is evaluated as good.
A MEF value exceeding 4.8 was evaluated as x when the MEF was not good.
The results are shown in Table 3. Numerical values in parentheses indicate MEF values.

  Since the resist composition containing the salt of the present invention can produce a resist pattern with a good mask error factor (MEF), it is suitable for fine processing of semiconductors.

Claims (12)

A salt represented by the formula (I).
[In the formula (I),
X represents an oxygen atom, a sulfur atom or —N (SO ₂ R ⁵ ) —.
R ⁵ may have an alkyl group having 1 to 12 carbon atoms which may have a fluorine atom, an alicyclic hydrocarbon group having 3 to 12 carbon atoms which may have a fluorine atom, or a fluorine atom. It represents an aromatic hydrocarbon group having 6 to 12 carbon atoms, and —CH ₂ — contained in the alkyl group or the alicyclic hydrocarbon group may be replaced by —O— or —CO—.
Ar is a divalent aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or a divalent heteroaromatic hydrocarbon having 4 to 36 carbon atoms which may have a substituent. Represents a group.
R ¹ and R ² each independently represent a hydrogen atom, a hydroxy group or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group is —O— or —CO—. It may be replaced.
m and n each independently represents 1 or 2. When m is 2, two R ¹ are the same or different, and when n is 2, two R ² are the same or different.
X ¹ represents * —O—, * —O—CO—, * —CO—O—, * —O—CO—O— or * —O—CH ₂ —CO—O—. * Represents a bonding position with Ar.
W represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group. The hydrogen atom contained in the alicyclic hydrocarbon group is a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alicyclic hydrocarbon having 3 to 12 carbon atoms. It may be substituted with a group, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a combination thereof.
A ⁻ represents an organic anion. ] The salt according to claim ¹ , wherein X ¹ is * —O—CO— (* represents a bonding position with Ar).   W is a cyclohexyl group, norbornyl group or adamantyl group, and the methylene group contained in the cyclohexyl group, norbornyl group or adamantyl group may be substituted with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group, The hydrogen atom contained in the cyclohexyl group, norbornyl group or adamantyl group is a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alicyclic hydrocarbon having 3 to 12 carbon atoms. The salt according to claim 1 or 2, which may be substituted with a group, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a combination thereof.   The salt according to any one of claims 1 to 3, wherein Ar is a phenylene group.   The salt according to any one of claims 1 to 4, wherein the organic anion is an organic sulfonate anion. The salt according to any one of claims 1 to 4, wherein the organic anion is an anion represented by the formula (IA).
[In the formula (IA),
Q ¹ and Q ² 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 saturated hydrocarbon group may be replaced by —O— or —CO—, and The hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Y represents an optionally substituted methyl group or an optionally substituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and is included in the alicyclic hydrocarbon group − CH ₂ — may be replaced by —O—, —SO ₂ — or —CO—. ] The salt according to claim 6, wherein Y represents an adamantyl group which may have a substituent, and —CH ₂ — contained in the adamantyl group may be replaced with —O— or —CO—.   A resist composition comprising the salt according to claim 1 and a resin having an acid labile group.   The resist composition according to claim 8, wherein the resin having an acid labile group further contains a structural unit having a lactone ring.   The resist composition according to claim 8 or 9, further comprising a salt that generates an acid having a lower acidity than an acid generated from an acid generator.   Furthermore, the resist composition in any one of Claims 8-10 containing resin containing the structural unit which has a fluorine atom. (1) The process of apply | coating the resist composition in any one of Claims 8-11 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including: