JP2014019690A - Salt, resist composition and production method of resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist composition from which a resist pattern with excellent pattern collapse resistance can be produced.SOLUTION: A resist pattern with excellent pattern collapse resistance can be produced by using a resist composition containing a salt expressed by formula (I) as an acid generator.

Description

  The present invention relates to a salt for an acid generator used for microfabrication of a semiconductor, 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.

JP 2003-342254 A

  In the resist composition containing the above-described salt as an acid generator, the resistance to pattern collapse of the resist pattern may not always be sufficiently satisfied.

The present invention includes the following inventions.
[1] A salt represented by the formula (I).

[In the formula (I),
R ^s1 , R ^s2 , R ^s5 and R ^s6 are each independently an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms. And —CH ₂ — contained in the alicyclic hydrocarbon group may be replaced by —O— or —CO—. R ^s1 and R ^s2 may together form a 3- to 12-membered ring with the sulfur atom to which they are bonded, and R ^s5 and R ^s6 are the sulfur to which they are bonded together. A 3-membered ring to a 12-membered ring may be formed together with atoms, and —CH ₂ — contained in these rings may be replaced with —O— or —CO—.
R ^s3 and R ^s4 each independently represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
L ^s1 represents a single bond or a divalent hydrocarbon group having 1 to 36 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
R ^s7 , R ^s8 , R ^s10 and R ^s11 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^s2 and L ^s3 each independently represent a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms which may have a substituent.
X ^s1 and X ^s2 represent —O—CO— or —O—.
R ^s9 and R ^s12 each independently represents an optionally substituted saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group is —O— , —SO ₂ — or —CO— may be substituted. ]
[2] The salt according to [1], wherein L ^s1 is a single bond, a carbonyl group, a phenylene group, an alkanediyl group having 1 to 18 carbon atoms, or a group represented by the formula (xs1).

[In the formula (xs1), L ^s4 represents a divalent hydrocarbon group having 1 to 32 carbon atoms. ]

[3] The salt according to the above [1] or [2], wherein R ^s9 and R ^s12 are a group represented by the formula (I-A1-1).

[In formula (I-A1-1), W ^s1 represents an alicyclic saturated hydrocarbon group having 3 to 24 carbon atoms which may have a substituent.
L ^s21 represents a C1-C21 divalent saturated hydrocarbon group which may have a single bond or a substituent.
However, the upper limit of the total carbon number of W ^s1 and L ^s21 is 24.
Note that —CH ₂ — contained in the alicyclic saturated hydrocarbon group of W ^s1 may be replaced by —O—, —SO ₂ — or —CO—. ]

[4] An acid generator containing the salt according to any one of [1] to [3].
[5] A resist composition comprising the acid generator according to the above [4] and a resin having an acid labile group.
[6] The resist composition according to [5], further containing a basic compound.
[7] (1) A step of applying the resist composition according to [5] or [6] 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 using an exposure machine;
(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.

  If a resist composition containing the salt of the present invention is used as an acid generator, a resist pattern having excellent pattern collapse resistance can be produced.

<Salt>
The salt of the present invention is a salt represented by the formula (I) (hereinafter sometimes referred to as “salt (I)”).

[In the formula (I),
R ^s1 , R ^s2 , R ^s5 and R ^s6 are each independently an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms. And —CH ₂ — contained in the alicyclic hydrocarbon group may be replaced by —O— or —CO—. R ^s1 and R ^s2 may together form a 3- to 12-membered ring with the sulfur atom to which they are bonded, and R ^s5 and R ^s6 are the sulfur to which they are bonded together. A 3-membered ring to a 12-membered ring may be formed together with atoms, and —CH ₂ — contained in these rings may be replaced with —O— or —CO—.
R ^s3 and R ^s4 each independently represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
L ^s1 represents a single bond or a divalent hydrocarbon group having 1 to 36 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
R ^s7 , R ^s8 , R ^s10 and R ^s11 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^s2 and L ^s3 each independently represent a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms which may have a substituent.
X ^s1 and X ^s2 represent —O—CO— or —O—.
R ^s9 and R ^s12 each independently represents an optionally substituted saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group is —O— , —SO ₂ — or —CO— may be substituted. ]

In the following description, in the salt (I), the side having a positive charge may be referred to as “cation (IC)” and the side having a negative charge may be referred to as “anion (IA)”.
The anion (IA) of the salt represented by the formula (I) is a sulfonate anion represented by the formula (I-A1) or the formula (I-A2). The sulfonate anions of formula (I-A1) and formula (I-A2) may be the same or different, but are preferably the same.

[In the formulas (I-A1) and (I-A2), R ^s7 , R ^s8 , R ^s9 , R ^s10 , R ^s11 , R ^s12 , L ^s2 , L ^s3 , X ^s1 , X ^s2 are represented by the above formula ( Same as I)]

^Examples of the perfluoroalkyl group ^{represented by} R ^s7 , R ^s8 , R ^s10, and R ^s11 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, and a perfluorotert-butyl group. A butyl group, a perfluoropentyl group, a perfluorohexyl group, etc. are mentioned.
As the anion (IA) of the acid generator used in the resist composition of the present invention, R ^s7 , R ^s8 , R ^s10 and R ^s11 are each independently an anion (IA) which is a trifluoromethyl group or a fluorine atom. An anion (IA) in which all are fluorine atoms is preferred.

Examples of the divalent saturated hydrocarbon group of L ^s2 and L ^s3 include a linear alkanediyl group, a branched alkanediyl group, a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group. A combination of two or more of these groups may be used.

Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1 , 6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group , Dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, ethane-1,1-diyl group, propane-1, Linear alkanediyl groups such as a 1-diyl group and a propane-2,2-diyl group;
An alkyl group (particularly an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group); For example, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl A branched alkanediyl group such as a 2-methylbutane-1,4-diyl group;
Cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,2-diyl group, 1-methylcyclohexane-1,2-diyl group, cyclohexane-1,4-diyl group, cyclo A monocyclic divalent alicyclic saturated hydrocarbon group which is a cycloalkanediyl group such as an octane-1,2-diyl group or a cyclooctane-1,5-diyl group;
Norbornane-2,3-diyl group, norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,2-diyl group, adamantane-1,5-diyl group, adamantane-2,6 -Polycyclic bivalent alicyclic saturated hydrocarbon groups, such as a diyl group.

Examples of the substituent for the divalent saturated hydrocarbon group of L ^s2 and L ^s3 include a halogen atom such as a fluorine atom, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, an acyloxy group having 1 to 6 carbon atoms, and the like. . Examples of L ^s2 and L ^s3 having a substituent include groups represented by the following formulas. In the formula, * represents a bond.

X ^s1 and X ^s2 are preferably —O—CO—. —O—CO— may be bonded in either direction, but is preferably bonded to L ^s2 or L ^s3 on the CO side.

Examples of the saturated hydrocarbon group for R ^s9 and R ^s12 include a chain saturated hydrocarbon group, an alicyclic saturated hydrocarbon group, and a combination thereof, and preferably a group containing an alicyclic saturated hydrocarbon group. is there. Note that —CH ₂ — contained in these chain saturated hydrocarbon group and alicyclic saturated hydrocarbon group may be replaced by —O—, —SO ₂ — or —CO—.
Examples of the chain saturated hydrocarbon group for R ^s9 and R ^s12 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and the like. 1 to 6 chain saturated hydrocarbon groups.
Examples of the alicyclic saturated hydrocarbon group for R ^s9 and R ^s12 include groups represented by formulas (Y1) to (Y11). Examples of the group in which —CH ₂ — contained in the alicyclic saturated hydrocarbon group is replaced with —O—, —SO ₂ — or —CO— include, for example, those represented by formula (Y12) to formula (Y26): And the group represented. In the formula, * represents a bond.

The alicyclic saturated hydrocarbon group for R ^s9 and R ^s12 is preferably a group represented by any one of formulas (Y1) to (Y19), more preferably formula (Y11), formula (Y14), It is group represented by Formula (Y15) or Formula (Y19), More preferably, it is group represented by Formula (Y11) or Formula (Y14).

As a group combining the chain saturated hydrocarbon group and the alicyclic saturated hydrocarbon group of R ^s9 and R ^s12 , a hydrogen atom contained in the chain saturated hydrocarbon group is substituted with an alicyclic saturated hydrocarbon group. And a group in which a hydrogen atom contained in an alicyclic saturated hydrocarbon group is substituted with a chain saturated hydrocarbon group.

Examples of the substituent of the saturated hydrocarbon group of R ^s9 and R ^s12 include a halogen atom, a hydroxy group, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and preferably a halogen atom or a hydroxy group.
As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom etc. are mentioned, for example, Preferably it is a fluorine atom.
Examples of the aromatic hydrocarbon group include a tolyl group such as a phenyl group, a naphthyl group, an anthryl group, and a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group, a xylyl group, a cumenyl group, and a mesityl group. Group, biphenyl group, phenanthryl group, 2,6-diethylphenyl group, aryl group such as 2-methyl-6-ethylphenyl group, and the like.

R ^s9 and R ^s12 are preferably groups represented by formula (I-A1-1), formula (I-A1-2), formula (I-A1-3), or formula (I-A1-4). It is.

[In formula (I-A1-1), W ^s1 represents an alicyclic saturated hydrocarbon group having 3 to 24 carbon atoms which may have a substituent.
L ^s21 represents a C1-C21 divalent saturated hydrocarbon group which may have a single bond or a substituent.
However, the upper limit of the total carbon number of W ^s1 and L ^s21 is 24.
Note that —CH ₂ — contained in the alicyclic saturated hydrocarbon group of W ^s1 may be replaced by —O—, —SO ₂ — or —CO—. ]
Examples of the alicyclic saturated hydrocarbon group for W ^s1 include the groups exemplified as the alicyclic saturated hydrocarbon group in R ^s9 and R ^s12 .

Examples of the substituent that the alicyclic saturated hydrocarbon group represented by W ^s1 may have include a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, and an alkyl group having 1 to 12 carbon atoms containing a hydroxy group. , An alicyclic hydrocarbon group having 3 to 16 carbon atoms, 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, and 2 to 4 carbon atoms An acyl group, a glycidyloxy group or — (CH ₂ ) _h —O—CO—R ^b1 group (wherein R ^b1 is an alkyl group having 1 to 16 carbon atoms and an alicyclic hydrocarbon group having 3 to 16 carbon atoms) Alternatively, it represents an aromatic hydrocarbon group having 6 to 18 carbon atoms, and h represents an integer of 0 to 4.

As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, for example.
Examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group and the like.
Examples of the hydroxy group-containing alkyl group include a hydroxymethyl group and a hydroxyethyl group.
Examples of the alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, and a cyclodecyl 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 aromatic hydrocarbon group include phenyl group, naphthyl group, anthryl group, p-tert-butylphenyl group, p-adamantylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, biphenyl group, phenanthryl group. , Aryl groups such as 2,6-diethylphenyl group and 2-methyl-6-ethylphenyl group.
Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group, and a naphthylethyl group.
Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group.

Examples of the alicyclic saturated hydrocarbon group having a substituent in W ^s1 include the following. In the formula, * represents a bond.

W ^s1 is preferably an alicyclic saturated hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, more preferably an adamantyl group which may have a substituent, and more preferably Is an adamantyl group, a hydroxyadamantyl group or an oxoadamantyl group.

As the divalent saturated hydrocarbon group for L ^s21 , methylene group, ethylene group, ethane-1,1-diyl group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1, 4-diyl group, butane-1,3-diyl group, pentane-1,5-diyl group, pentane-1,4-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, heptadecane-1,17-diyl group and the like. Preferably, it is a C1-C6 bivalent saturated hydrocarbon group, More preferably, a methylene group, ethylene group, a propane- 1, 3- diyl group, butane- 1, 4- diyl group, ethane- 1, A 1-diyl group, a propane-1,2-diyl group, a butane-1,3-diyl group or a pentane-1,4-diyl group, more preferably a methylene group.

Examples of the substituent that the divalent saturated hydrocarbon group of L ^s21 may have include a halogen atom and a hydroxy group. The halogen atom is preferably a fluorine atom.

The upper limit of the total carbon number of W ^s1 and L ^s21 is 24. However, when the alicyclic saturated hydrocarbon group of W ^{s1 has} an aromatic hydrocarbon group as a substituent, the carbon number of the aromatic hydrocarbon group is not included in the total carbon number of W ^s1 and L ^s21 .

  Formula (I-A1-2) is as follows.

[In Formula (I-A1-2), W ^s2 represents an alicyclic saturated hydrocarbon group having 3 to 22 carbon atoms which may have a substituent.
L ^s22 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms which may have a substituent.
L ^s23 represents a C1-C19 divalent saturated hydrocarbon group which may have a single bond or a substituent.
However, the upper limit of the total carbon number of W ^s2 , L ^s22 and L ^s23 is 23.
Note that —CH ₂ — contained in the alicyclic saturated hydrocarbon group of W ^s2 may be replaced by —O—, —SO ₂ —, or —CO—. ]
Examples of the alicyclic saturated hydrocarbon group for W ^s2 include the same groups as those for W ^s1 .
Examples of the divalent saturated hydrocarbon group for L ^s22 and L ^s23 include the same groups as those described above for L ^s21 .
W ^s2 is preferably an alicyclic saturated hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, more preferably an adamantyl group which may have a substituent. Is an adamantyl group, a hydroxyadamantyl group or an oxoadamantyl group.

As * -L ^s22 -O-L ^s23- *, a group of the following formula can be exemplified. * Represents a bond.

  Formula (I-A1-3) is as follows.

[In formula (I-A1-3), W ^s3 represents an alicyclic saturated hydrocarbon group having 3 to 21 carbon atoms which may have a substituent.
L ^s24 represents a C1-C19 divalent saturated hydrocarbon group which may have a single bond or a substituent. (However, when X ^s1 or X ^s2 is —O—CO—, L ^s24 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.)
L ^s25 represents a ^C1-C18 divalent saturated hydrocarbon group which may have a single bond or a substituent.
However, the upper limit of the total carbon number of W ^s3 , L ^s24 and L ^s25 is 22.
Note that —CH ₂ — contained in the alicyclic saturated hydrocarbon group of W ^s3 may be replaced by —O—, —SO ₂ — or —CO—. ]
Examples of the alicyclic saturated hydrocarbon group for W ^s3 include the same groups as those for W ^s1 .
^Examples of the divalent saturated hydrocarbon group for L ^s24 and L ^s25 include the same groups as those described above for L ^s21 .
W ^s3 is preferably an alicyclic saturated hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, more preferably an adamantyl group which may have a substituent, and more preferably Is an adamantyl group, a hydroxyadamantyl group or an oxoadamantyl group.
As * -L ^s24 -COO-L ^s25- *, a group of the following formula is preferably exemplified. * Represents a bond.

  Formula (I-A1-4) is as follows.

[In Formula (I-A1-4), W ^s4 represents an alicyclic saturated hydrocarbon group having 3 to 20 carbon atoms which may have a substituent.
L ^s26 represents a ^C 1-18 divalent saturated hydrocarbon group which may have a substituent.
L ^s27 and L ^s28 represents a divalent saturated hydrocarbon group of a single bond or a substituted carbon atoms, which may based on have 1-17.
However, the upper limit of the total number of carbon atoms in W ^s4, L ^s26, L ^s27 and L ^s28 is 21.
Note that —CH ₂ — contained in the alicyclic saturated hydrocarbon group of W ^s4 may be replaced by —O—, —SO ₂ —, or —CO—. ]

Examples of the alicyclic saturated hydrocarbon group for W ^s4 include the same groups as those described above for W ^s1 .
Examples of the divalent saturated hydrocarbon group of L ^s26, L ^s27 and L ^s28, the same groups as the L ^s21 can be exemplified.
W ^s4 is preferably an alicyclic saturated hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, more preferably an adamantyl group which may have a substituent, and more preferably Is an adamantyl group, a hydroxyadamantyl group or an oxoadamantyl group.
^{* -L s26 -O-L s27 -COO} -L s28 - The *, preferably, it may be exemplified groups represented by the following formula. * Represents a bond.

Among them, R ^s9 and R ^s12 are preferably a group represented by the formula (I-A1-1), and are —W ^s1 or —CH ₂ —W ^s1 (W ^s1 is as defined above). More preferably.

  Examples of the sulfonate anion include anions represented by the formulas (Ia-1) to (Ia-6) [hereinafter referred to as “anions (Ia-1)” depending on the formula number]. is there. ] Is more preferable.

Furthermore, as the sulfonate anion, the anion represented by the formula (Ia-7) to the formula (Ia-15) [hereinafter referred to as “anion (Ia-7)” according to the formula number, etc.] There is a case. ] Is preferable. R ^s21 and R ^s22 are independently synonymous with R ^s7 , R ^s8 , R ^s10 , and R ^s11 . R ^s23 has the same ^definition as the substituent that the alicyclic saturated hydrocarbon group of W ^{s1 to} W ^s4 may have, and is preferably an alkyl group having 1 to 4 carbon atoms or a hydroxy group. A methyl group or a hydroxy group is more preferable. R ^s24 is an alkyl group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 6 carbon atoms, and more preferably a methyl group. L ^1, the ^{-L s21 -, - L s22 -O} -L s23 -, L s24 -COO-L s25 -, or ^{-L s26 -O-L s27 -COO-} L s28 - a.

<Cation (IC)>
The cation (IC) of the salt represented by the formula (I) is represented by the formula (IB).

[In the formula (IB),
R ^s1 , R ^s2 , R ^s5 and R ^s6 are each independently an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms. And —CH ₂ — contained in the alicyclic hydrocarbon group may be replaced by —O— or —CO—. R ^s1 and R ^s2 may together form a 3- to 12-membered ring with the sulfur atom to which they are bonded, and R ^s5 and R ^s6 are the sulfur to which they are bonded together. A 3-membered ring to a 12-membered ring may be formed together with atoms, and —CH ₂ — contained in these rings may be replaced with —O— or —CO—.
R ^s3 and R ^s4 each independently represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
L ^s1 represents a single bond or a divalent hydrocarbon group having 1 to 36 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—. ]

Examples of the alkyl group having 1 to 18 carbon atoms of R ^s1 , R ^s2 , R ^s3 , R ^s4 , R ^s5 and R ^s6 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, sec- A butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group and a 2-ethylhexyl group can be mentioned. In particular, the alkyl group preferably has 1 to 12 carbon atoms.
The alicyclic hydrocarbon group having 3 to 18 carbon atoms of R ^s1 , R ^s2 , R ^s3 , R ^s4 , R ^s5 and R ^s6 may be either monocyclic or polycyclic, and the alicyclic carbonization. A hydrogen atom contained in the hydrogen group may be substituted with an alkyl group. In this case, the carbon number of the alicyclic hydrocarbon group is 18 or less including the carbon number of the alkyl group. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups. Hereinafter, * in the illustration of each group represents a bond.

In particular, the alicyclic hydrocarbon group preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms.
Examples of the group in which —CH ₂ — contained in the alicyclic hydrocarbon group is replaced by —O— or —CO— include the following groups.

R ^s1 and R ^s2 and R ^s5 and R ^s6 are preferably a 3-membered to 7-membered ring as the ring formed together with the sulfur atom to which they are bonded. —CH ₂ — contained in the ring may be replaced with —O— or —CO—. Examples of the ring include the rings represented below.

Examples of the aromatic hydrocarbon group having 6 to 18 carbon atoms of R ^s1 , R ^s2 , R ^s3 , R ^s4 , R ^s5 and R ^s6 include a phenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, p -Ethylphenyl group, p-tert-butylphenyl group, p-cyclohexylphenyl group, p-adamantylphenyl group, biphenylyl group, naphthyl group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6- An ethylphenyl group etc. are mentioned.

Examples of the divalent hydrocarbon group having 1 to 36 carbon atoms of L ^s1 include a divalent aliphatic hydrocarbon group, a divalent alicyclic hydrocarbon group, a divalent aromatic hydrocarbon group, or these groups. Examples thereof include a divalent group in which two or more are combined. —CH ₂ — contained in a divalent aliphatic hydrocarbon group, a divalent alicyclic hydrocarbon group, and a divalent group obtained by combining two or more of these groups is replaced with —O— or —CO—. It may be.
The divalent aliphatic hydrocarbon group includes methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, butane-1,2- Diyl group, butane-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, heptadecane-1,17-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group and propane-2 Straight chain such as 2-diyl group Alkanediyl group, and in these the linear alkanediyl group include branched alkanediyl group which alkyl group is substituted.
The divalent alicyclic hydrocarbon group includes cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,1-diyl group, cyclohexane-1,2-diyl group, 1 -Monocyclic divalent alicyclic rings such as methylcyclohexane-1,2-diyl group, cyclohexane-1,4-diyl group, cyclooctane-1,2-diyl group, cyclooctane-1,5-diyl group A hydrocarbon group of formula;
Norbornane-2,3-diyl group, norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,2-diyl group, adamantane-1,5-diyl group, adamantane-2,6 -Polycyclic bivalent alicyclic hydrocarbon groups, such as a diyl group, etc. are mentioned.
The divalent aromatic hydrocarbon group includes 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, naphthalene-1,2-diyl group, naphthalene-1,3-diyl group, Naphthalene-1,4-diyl group, naphthalene-1,5-diyl group, naphthalene-1,6-diyl group, naphthalene-1,7-diyl group, naphthalene-1,8-diyl group, naphthalene-2,3 -A monocyclic or condensed divalent aromatic hydrocarbon group such as a diyl group, a naphthalene-2,6-diyl group, and a naphthalene-2,7-diyl group.
Examples of the group in which these are combined include, for example, a divalent group in which an alicyclic hydrocarbon group and an aliphatic hydrocarbon group are combined, and a divalent group in which an aromatic hydrocarbon group and an aliphatic hydrocarbon group are combined. (Group A), a divalent group obtained by combining an aromatic hydrocarbon group and an alicyclic hydrocarbon group.

R ^s1 and R ^s2 are preferably joined together to form a ring with the sulfur atom to which they are attached, and R ^s5 and R ^s6 are also taken together to form a ring with the sulfur atom to which they are attached. Is preferred.
R ^s3 and R ^s4 are preferably hydrogen atoms.
L ^s1 is preferably a single bond, a carbonyl group, a phenylene group, an alkanediyl group having 1 to 18 carbon atoms, or a group represented by the formula (xs1).

[In the formula (xs1), L ^s4 represents a divalent hydrocarbon group having 1 to 32 carbon atoms. ]

Examples of the divalent hydrocarbon group include the same groups as those exemplified for L ^s1 .
L ^s4 is preferably a group represented by the formula (xs2) or a divalent saturated hydrocarbon group having 1 to 32 carbon atoms.

[In the formula (xs2), L ^s5 represents a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms.
A ^s1 and A ^s2 each independently represent an alkyl group having 1 to 4 carbon atoms.
x1 and x2 each independently represent an integer of 0 to 4. When x1 is 2 or more, the plurality of A ^s1 may be the same or different from each other. When x2 is 2 or more, the plurality of A ^s2 is They may be the same or different from each other.
However, the total carbon number of L ^s5 , A ^s1 and A ^s2 is 20 or less. ]
Desirable L ^s5 is represented by the formula (xs3).

[In formula (xs3), A ^s3 and A ^s4 each independently represent an alkanediyl group having 1 to 8 carbon atoms.
A ^s5 represents an alkyl group having 1 to 4 carbon atoms.
x5 represents an integer of 0 to 4, and when x5 is 2 or more, a plurality of ^As5 may be the same or different from each other]

Examples of the divalent saturated hydrocarbon group having ¹ to 32 carbon atoms of L ^s4 include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl. Group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, ethane-1,1-diyl group, propane-1 , 1-diyl group, propane-2,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane- Alkanediyl groups such as 1,4-diyl group and 2-methylbutane-1,4-diyl group; cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group , Cyclooctane-1,5-di Cycloalkanediyl group such group; and a group represented by the following formulas are exemplified.

[ ^Wherein , L ^s6 , L ^s7 and L ^s8 represent an alkanediyl group having 1 to 3 carbon atoms.
L ^s6 and L ^s7 are preferably a methylene group.
L ^s8 is preferably a propane-2,2-diyl group. ]

Examples of the group represented by the formula (xs1) when L ^s4 is a divalent saturated hydrocarbon group include the following divalent groups.

Examples of the group represented by the formula (xs1) when L ^s4 is a group represented by the formula (xs2) include a divalent group represented by the following.

  The cation of formula (IB) is preferably represented by formula (x1).

[In the formula (x1), R ^s1 , R ^s2 , R ^s5 , R ^s6 and L ^s4 have the same meaning as described above.]

  The cation of the formula (IB) is more preferably represented by the formula (x2).

[In the formula (x2), R ^s1 , R ^s2 , and L ^s4 have the same meaning as described above.]

  Examples of the cation (IC) include the following cations.

  Examples of the salt (I) include salts composed of anions (IA) and cations (IC) listed in Tables 1 to 3.

  Of these, the salts shown below are preferred.

In the resist composition described later, the content of the salt (I) as the acid generator is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, based on the solid content of the resist composition. More preferably, it is 1 mass% or more, Most preferably, it is 1.5 mass% or more. Moreover, 30 mass% or less is preferable, More preferably, it is 25 mass% or less, More preferably, it is 20 mass% or less, Most preferably, it is 15 mass% or less. In the resist composition of the present invention, when the content of the salt (I) as the acid generator is within the above range, the resist pattern collapse resistance property is good.
In the present specification, the “solid content of the resist composition” means the total of components excluding the solvent (D) described later from the total amount of the resist composition. The solid content of the resist composition and the resin content relative to the solid content can be measured, for example, by known analytical means such as liquid chromatography or gas chromatography.

  Examples of the salt represented by the formula (I) include a salt represented by the formula (I-a1), a salt represented by the formula (I-a2), and a salt represented by the formula (Ib). It can be produced by reacting in a solvent.

(In the formula, R ^s1 , R ^s2 , R ^s3 , R ^s4 , R ^s5 , R ^s6 , R ^s7 , R ^s8 , R ^s9 , R ^s10 , R ^s11 , R ^s12 , X ^s1 , X ^s2 , L ^s1 , L ^s2 and L ^s3 are as defined above.)

Examples of the solvent include chloroform / ion exchange water, acetonitrile / methanol and the like.
Examples of the salt represented by the formula (I-a1) and the formula (I-a2) include compounds represented by the following.

  The compound represented by the formula (Ib) includes a compound represented by the formula (Ic), a compound represented by the formula (I-d1), and a compound represented by the formula (Id2). It can be produced by reacting in a solvent.

Examples of the solvent include acetonitrile.

  Examples of the compound represented by the formula (Ic) include compounds represented by the following.

  Examples of the compound represented by the formula (I-d1) or the formula (I-d2) include compounds represented by the following.

<Acid generator>
The acid generator of the present invention contains the salt (I). The acid generator of the present invention may further contain an acid generator other than the salt (I) (hereinafter sometimes referred to as “acid generator (B)”).
As the acid generator (B), a known acid generator can be used, and an ionic acid generator or a nonionic generator may be used, but an ionic acid generator is preferable. Examples of the ionic acid generator include an ionic acid generator composed of a combination of a sulfonate anion constituting the salt (I) and a cation other than the cation (IC) constituting the salt (I), and a known cation. And an ionic acid generator composed of a combination with a known anion.

  As an acid generator (B), the salt represented by either of Formula (B1-1)-Formula (B1-20) is mentioned, for example. Among them, those containing a triarylsulfonium cation are preferable. Formula (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-6), Formula (B1-7), Formula (B1- 11) A salt represented by any one of formula (B1-12), formula (B1-13) and formula (B1-14) is more preferred.

  In the resist composition described later, the total content of the salt (I) as the acid generator and the acid generator (B) is preferably 0.1% by mass or more based on the solid content of the resist composition. Preferably it is 0.5 mass% or more, More preferably, it is 1 mass% or more, Most preferably, it is 1.5 mass% or more. Moreover, 30 mass% or less is preferable, More preferably, it is 25 mass% or less, More preferably, it is 20 mass% or less, Most preferably, it is 15 mass% or less.

  The amount of the salt (I) in the acid generator is, for example, 10% by mass or more, preferably 40% by mass or more, and more preferably, with respect to the total of the salt (I) and the other acid generator (B). It is 70% by mass or more, particularly preferably 90% by mass or more, and may be 100% by mass.

<Resist composition>
The resist composition of the present invention contains the acid generator of the present invention and a resin containing a structural unit having an acid labile group (hereinafter sometimes referred to as “resin (A)”).
<Resin (A)>
The resin (A) is a resin containing a structural unit having an acid labile group (hereinafter sometimes referred to as “structural unit (a1)”), and is decomposed by the action of an acid. A resin that exhibits solubility in an alkaline developer (such as tetramethylammonium hydroxide aqueous solution) by this decomposition, or a resin that has the property of decreasing solubility in an organic solvent (such as butyl acetate or 2-heptanone) is preferred.

<Structural unit a1>
The “acid labile group” means a group having a leaving group and forming a hydrophilic group (for example, a hydroxy group or a carboxy group) by leaving the leaving group by contact with an acid. Examples of the acid labile group include a group represented by the formula (1) and a group represented by the formula (2).

[In the formula (1), R ^a1 , R ^a2 and 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 group obtained by combining them. R ^a1 and R ^a2 are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms. * 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 hydrocarbon group having 2 to 20 carbon atoms, and —CH ₂ — contained in the hydrocarbon group and the divalent hydrocarbon group. May be replaced by -O- or -S-. * 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, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group.
The alicyclic hydrocarbon group for 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 a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups (* represents a bond). The alicyclic hydrocarbon group of R ^{a1 to} R ^a3 preferably has 3 to 16 carbon atoms.

  Examples of the group obtained by combining an alkyl group and an alicyclic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, and a methylnorbornyl group.

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 hydrocarbon group include the following groups. The divalent 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 (in the formula (1), R ^{a1 to} R ^a3 are alkyl groups, preferably a tert-butoxycarbonyl group), 2-alkyladamantan-2-yloxycarbonyl group (in the formula (1), R ^a1 , R ^a2 and a carbon atom 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 for R ^{a1 ′ to} R ^{a3 ′} include an alkyl group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group.
Examples of the alkyl group and alicyclic hydrocarbon group are the same as those described above.
Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl Groups, phenanthryl groups, 2,6-diethylphenyl groups, aryl groups such as 2-methyl-6-ethylphenyl, and the like.
Examples of the divalent hydrocarbon group formed by combining R ^{a2 ′} and R ^{a3 ′} include groups in which one hydrogen atom has been removed from the hydrocarbon groups of R ^{a1 ′ to} R ^{a3 ′} .

In Formula (2), it is preferable that at least one of R ^{a1 ′} and R ^{a2 ′} is a hydrogen atom.
Specific examples of the group represented by the formula (2) include the following groups. * Represents a bond.

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

  The (meth) acrylic structural unit (a1) into which an acid labile group has been introduced preferably has an alicyclic hydrocarbon group having 5 to 20 carbon atoms. If the resin (A) having the structural unit (a1) having a bulky structure such as an alicyclic hydrocarbon group is used in the resist composition, the resolution of the resist pattern can be improved.

As the (meth) acrylic structural unit having an acid labile group represented by the formula (1), preferably a structural unit represented by the formula (a1-1), a structural unit represented by the formula (a1-2) And a structural unit represented by formula (a1-3). These may be used alone or in combination of two or more. In this specification, the structural unit represented by formula (a1-1), the structural unit represented by formula (a1-2), and the structural unit represented by formula (a1-3) are each represented by structural unit (a1). -1), structural unit (a1-2), and structural unit (a1-3).
First, the structural unit represented by the formula (a1-1) and the structural unit represented by the formula (a1-2) will be described.

[In Formula (a1-1) and Formula (a1-2),
L ^a1 and L ^a2 each independently represent —O— or ^* —O— (CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, and * represents a bond to —CO—. Represents a hand.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group obtained by combining these.
m1 represents the integer of 0-14.
n1 represents an integer of 0 to 10.
n1 ′ represents an integer of 0 to 3. ]

L ^a1 and L ^a2 are preferably —O— or ^* —O— (CH ₂ ) _k1 —CO—O—, and more preferably —O—. k1 is preferably an integer of 1 to 4, more preferably 1.
R ^a4 and R ^a5 are preferably methyl groups.
Examples of the alkyl group of R ^a6 and R ^a7 , the alicyclic hydrocarbon group, and the group obtained by combining these include the same groups as those described for R ^{a1 to} R ^a3 in formula (1).
The alkyl group for R ^a6 and R ^a7 preferably has 6 or less carbon atoms.
The alicyclic hydrocarbon group of R ^a6 and R ^a7 preferably has 8 or less carbon atoms, more preferably 6 or less.
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 a monomer which introduce | transduces structural unit (a1-1), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Among these, a monomer represented by any one of formula (a1-1-1) to formula (a1-1-8) is preferable, and any one of formula (a1-1-1) to formula (a1-1-4) is preferable. The monomer represented by is more preferable.

  Examples of the monomer that leads to the structural unit (a1-2) include 1-ethylcyclopentan-1-yl (meth) acrylate, 1-ethylcyclohexane-1-yl (meth) acrylate, and 1-ethylcycloheptane-1- Il (meth) acrylate, 1-methylcyclopentan-1-yl (meth) acrylate, 1-isopropylcyclopentan-1-yl (meth) acrylate, and the like can be given. Monomers represented by the formula (a1-2-1) to the formula (a1-2-12) are preferred, and the formula (a1-2-3) to the formula (a1-2-4) or the formula (a1-2-9) The monomer represented by formula (a1-2-10) is more preferable, and the monomer represented by formula (a1-2-3) or formula (a1-2-9) is more preferable.

  When the resin (A) contains the structural unit (a1-1) and / or the structural unit (a1-2), the total content thereof is usually 10 to 95 mol with respect to all the structural units of the resin (A). %, Preferably 15 to 90 mol%, more preferably 20 to 85 mol%.

  The structural unit represented by the formula (a1-3) is as follows.

[In the formula (a1-3),
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 ] _k1 —CO—L ^a6 —. Here, k1 represents an integer of 1 to 4. * Represents a bond with L ^a3 .
L ^a3 , L ^a4 , L ^a5 and L ^a6 each independently represent —O— or —S—.
s1 represents an integer of 1 to 3.
s1 ′ represents an integer of 0 to 3. ]

In formula (a1-3), R ^a8 is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.
L ^a3 is preferably —O—.
One of L ^a4 and L ^a5 is preferably —O— and the other is —S—.
s1 is preferably 1.
s1 ′ is preferably an integer of 0 to 2.
Z ^a1 is preferably a single bond or * —CH ₂ —CO—O—.

  Examples of the monomer that leads to the structural unit (a1-3) include the following monomers.

  When the resin (A) has the structural unit (a1-3), the content is preferably from 1 to 50 mol%, more preferably from 3 to 45 mol%, based on all the structural units of the resin (A). 5 to 40 mol% is more preferable.

  The resin (A) preferably contains the structural unit (a1-1) and / or the structural unit (a1-2) as the structural unit (a1), and more preferably contains the structural unit (a1-1).

<Structural unit without acid labile group>
The resin (A) may have a structural unit having no acid labile group (hereinafter sometimes referred to as “structural unit (s)”). The monomer for deriving the structural unit (s) is not particularly limited as long as it does not have an acid labile group, and monomers 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 structural unit having a hydroxy group and having no acid labile group (hereinafter sometimes referred to as “structural unit (a2)”) and / or a lactone ring and having no acid labile group ( If a resin having a “structural unit (a3)” hereinafter) is used for the resist composition, 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. 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 ^a6 represents —O— or ^* —O— (CH ₂ ) _k2 —CO—O—,
k2 represents an integer of 1 to 7. * Represents a bond with -CO-.
R ^a10 represents a hydrogen atom or a methyl group.
R ^a11 and R ^a12 each independently represents a hydrogen atom, a methyl group or a hydroxy group.
o1 represents an integer of 0 to 10. ]

In the formula (a2-1), L ^a6 is preferably, -O -, - O- (CH 2) f1 -CO-O- and is (wherein f1 is an integer from 1 to 4), more preferably Is —O—.
R ^a10 is preferably a methyl group.
R ^a11 is preferably a hydrogen atom.
R ^a12 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, more preferably 0 or 1.

  As a monomer which introduce | transduces structural unit (a2-1), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. A monomer represented by any one of formula (a2-1-1) to formula (a2-1-6) is preferable, and represented by any one of formula (a2-1-1) to formula (a2-1-4). The monomer represented by Formula (a2-1-1) or Formula (a2-1-3) is more preferable.

  When the resin (A) includes the structural unit (a2), the content is usually 3 to 45 mol%, preferably 1 to 40 mol%, based on all the structural units of the resin (A). More preferably, it is 1-35 mol%, More preferably, it is 2-20 mol%.

<Structural unit (a3)>
The lactone ring contained in the structural unit (a3) may be, for example, a monocycle such as a β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, and a bridged ring including these monocyclic lactone ring structures. But you can. Among these lactone rings, a γ-butyrolactone ring or a bridged ring containing a γ-butyrolactone ring structure is preferable.

  The structural unit (a3) is preferably a structural unit represented by any one of the formulas (a3-1) to (a3-4). These 1 type may be contained independently and 2 or more types may be contained.

[In the formula (a3-1),
L ^a7 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a21 represents a hydrogen atom or a methyl group.
R ^a25 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents an integer of 0 to 5. When p1 is 2 or more, the plurality of ^Ra25s are the same or different from each other.
In formula (a3-2),
L ^a8 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a22 represents a hydrogen atom or a methyl group.
R ^a26 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
q1 represents an integer of 0 to 3. When q1 is 2 or more, the plurality of R ^a26 are the same or different from each other.
In formula (a3-3),
L ^a9 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a23 represents a hydrogen atom or a methyl group.
R ^a27 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
r1 represents an integer of 0 to 3. When r1 is 2 or more, the plurality of R ^a27 are the same or different from each other.
In formula (a3-4),
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.
A ^a1 is a single bond, ^* —A ^a2 —O—, ^* —A ^a2 —CO—O—, ^* —A ^a2 —CO—O—A ^a3 —CO—O— or ^* —A ^a2 —O—CO —A ^a3 —O— is represented.
* Represents a bond with -O-.
A ^a2 and A ^a3 each independently represent an alkanediyl group having 1 to 6 carbon atoms. ]

In formula (a3-1) to formula (a3-3), L ^{a7 to} L ^a9 are preferably each independently —O— or ^* —O— (CH ₂ ) _k3 —CO—O—. In formula (a3-1) and formula (a3-3), more preferably -O-. In the formula (a3-2), more preferably —O— (CH ₂ ) _k3 —CO—O—. k3 is preferably an integer of 1 to 4, more preferably 1.
R ^{a21 to} R ^a23 are preferably methyl groups.
R ^a24 is preferably a methyl group.
R ^a25 is preferably a methyl group.
R ^a26 and R ^a27 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1 to r1 are each independently preferably 0 to 2, more preferably 0 or 1.
A ^a2 and A ^a3 are preferably each independently a methylene group or an ethylene group.

  As a monomer which introduce | transduces structural unit (a3-1), (a3-2), or (a3-3), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Formula (a3-1-1) to Formula (a3-1-4), Formula (a3-2-1) to Formula (a3-2-4), and Formula (a3-3-1) to Formula (a3-3) -4) is preferred, and the monomers represented by formula (a3-1-1) to formula (a3-1-2) and formula (a3-2-3) to formula (a3-2-4) are preferred. The monomer represented by either is more preferable, and the monomer represented by the formula (a3-1-1) or the formula (a3-2-3) is more preferable.

  The monomer that leads to the structural unit (a3-4) is represented by the formula (a3-4 ′).

[In formula (a3-4 ′), R ^a24 and A ^a1 represent the same meaning as described above. ]

Compound (a3-4 ′) [represented by the formula (a3-4′-1), wherein A ^a1 is * —CH ₂ —CO—O— (* represents a bond to —CO—O—). Can be produced by reacting the compound represented by the formula (a3-4′-1-a) with the compound represented by the formula (a3-4′-1-b) in a solvent. . Examples of the solvent used for the reaction include methylene chloride, tetrahydrofuran and acetonitrile.

  The compound represented by the formula (a3-4′-1-a) is represented by the compound represented by the formula (a3-4′-1-c) and the formula (a3-4′-1-d). It can manufacture by making the compound react.

  This reaction is preferably carried out in the presence of a solvent such as methylene chloride, tetrahydrofuran and acetonitrile. In this reaction, a condensing agent such as dicyclohexylcarbodiimide may be used.

  Examples of the compound represented by the formula (a3-4′-1-c) include the following compounds. This compound is readily available from the market.

  Examples of the compound (a3-4 ′) include the following.

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%.
In addition, the contents of the structural unit (a3-1), the structural unit (a3-2), the structural unit (a3-3), and the structural unit (a3-4) are each in the total structural unit of the resin (A). On the other hand, 5-60 mol% is preferable, 5-50 mol% is more preferable, and 10-50 mol% is further more preferable.

<Other structural units (s)>
As the structural unit (s), in addition to the structural unit derived from the monomer (a2) and the structural unit derived from the monomer (a3), a structural unit having a halogen atom (hereinafter sometimes referred to as “structural unit (a4)”). Is mentioned.

  As a structural unit (a4), the structural unit represented by a formula (a4-1) is mentioned, for example.

[In the formula (a4-1),
R ^a41 represents a monovalent hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced with —O— or —CO—.
A ^a41 is an alkanediyl group having 1 to 6 carbon atoms which may have a substituent or a formula (a-g1).

[In the formula (a-g1),
s represents 0 or 1.
A ^a42 and A ^a44 each independently represent an ^optionally substituted aliphatic hydrocarbon group having 1 to 5 carbon atoms.
A ^a43 represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms 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. ]
Represents a group represented by
R ^a42 represents an ^optionally substituted hydrocarbon group having 1 to 20 carbon atoms.
However, at least one of A ^a41 and R ^a42 is a group having a halogen atom. ]

As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned, Preferably it is a fluorine atom.
The aliphatic hydrocarbon group may have a carbon-carbon unsaturated bond, but is preferably an aliphatic saturated hydrocarbon group. Examples of the aliphatic saturated hydrocarbon group include an alkyl group (the alkyl group may be linear or branched), an alicyclic hydrocarbon group, and an aliphatic combination of an alkyl group and an alicyclic hydrocarbon group. Group hydrocarbon group and the like.

^Examples of the hydrocarbon group for R ^a41 include chain and cyclic aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and groups in which these are combined. Examples of chain aliphatic hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, hexadecyl, pentadecyl, and hexyl. A decyl group, a heptadecyl group, an octadecyl group, etc. are mentioned. Examples of the cyclic aliphatic 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).

  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.

^Examples of the hydrocarbon group for R ^a42 include chain and cyclic aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and groups in which these are combined, and chain and cyclic aliphatic hydrocarbons. Group and a group in which these are combined, and may have a carbon-carbon unsaturated bond, but a chain and cyclic aliphatic saturated hydrocarbon group and a group in which these are combined are more preferable. . Specifically, the same group as R ^a41 is ^exemplified .
R ^a42 is preferably an aliphatic hydrocarbon group, and more preferably an aliphatic hydrocarbon group having a halogen atom and / or a group represented by the formula (a-g2).

[In the formula (a-g2),
X ^a43 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ^a45 represents a C ^3-17 aliphatic hydrocarbon group having at least one halogen atom. ]
When R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula (a-g2), including the carbon number contained in the group represented by the formula (a-g2), 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-g2) as a substituent, the number is preferably one.

  The aliphatic hydrocarbon having a group represented by the formula (a-g2) is more preferably a group represented by the formula (a-g3).

[In the formula (a-g3),
A ^a46 represents an aliphatic hydrocarbon group having 3 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 3 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. ]

Preferred R ^a42 , an aliphatic hydrocarbon group having a substituent selected from the group consisting of a halogen atom and a group represented by formula (a-g2) (a group represented by formula (a-g3)) Detailed description.

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.

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 A ^<a47> , 5-12 are more preferable, and A ^<a47> has a more preferable cyclohexyl group or an adamantyl group.

Among the combinations of A ^a46 and A ^a47, the more preferable, * - is represented by the partial structure represented by A ^a46 -X ^a44 -A ^a47 (* represents a bond to a carbonyl group), the following structure Is mentioned.

^As the alkanediyl group of ^Aa41 , 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.
^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.

In the group represented by the formula (a-g1) of A ^a41 (hereinafter sometimes referred to as “group (a-g1)”), A ^a44 is ^bonded to —O—CO—R ^a42 .
As the aliphatic hydrocarbon group for A ^a42 , A ^a43 and A ^{a44 in} the group (a-g1), a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane- Examples include 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 is an oxygen atom include the following groups. In the following examples, among the two bonds represented by *, * on the right side is a bond with —O—CO—R ^a42 .

Examples of the group (a-g1) in which X ^a42 is a carbonyl group include the following groups.

Examples of the group (a-g1) in which X ^a42 is a carbonyloxy group include the following groups.

Examples of the group (a-g1) in which X ^a42 is an oxycarbonyl group include the following groups.

  As the structural unit represented by the formula (a4-1), a structural unit represented by the formula (a4-2) or the formula (a4-3) is 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 for R ^f2 includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group, and the aliphatic hydrocarbon group includes a chain type, a cyclic group, and 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, pentyl group, hexyl group, octyl group and 2-ethylhexyl group. .
The alicyclic hydrocarbon group may be monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a methyl group. Examples thereof include cycloalkyl groups such as cyclohexyl group, 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, and norbornyl. Group, methylnorbornyl group and isobornyl group.

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), as A ^f1 , an alkanediyl group having 2 to 4 carbon atoms is preferable, and an ethylene group is more preferable.
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 in which these are combined. 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 , either a chain or a cyclic group, and an aliphatic hydrocarbon group in which these are combined 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 of 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 and pentyl group, hexyl group, perfluorohexyl group, A heptyl group, a perfluoro heptyl group, an octyl group, a perfluorooctyl group, etc. are mentioned.
Etc.
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, and 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.

  Examples of the monomer for deriving the structural unit represented by formula (a4-2) include monomers represented by formula (a4-1-1) to formula (a4-1-22), respectively.

  Examples of the monomer for deriving the structural unit represented by formula (a4-3) include monomers represented by formula (a4-1′-1) to formula (a4-1′-22), respectively.

  Examples of the structural unit (a4) include a structural unit represented by the formula (a4-4).

[In the formula (a4-4),
R ^f21 represents a hydrogen atom or a methyl group.
A ^f21 represents — (CH ₂ ) _j1 —, — (CH ₂ ) _j2 —O— (CH ₂ ) _j3 — or — (CH ₂ ) _j4 —CO—O— (CH ₂ ) _j5 —.
j1 to j5 each independently represents an integer of 1 to 6.
R ^f22 represents a C 1-10 hydrocarbon group having a fluorine atom. ]

^Examples of the hydrocarbon group having a fluorine atom of R ^f22 include the same hydrocarbon groups as R ^f2 in formula (a4-2). R ^f22 is preferably a ^C 1-10 alkyl group having a fluorine atom or a C 1-10 alicyclic hydrocarbon group having a fluorine atom, more preferably a C 1-10 alkyl group having a fluorine atom. Preferably, the C1-C6 alkyl group which has a fluorine atom is further more preferable.

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

  Examples of the monomer for deriving the structural unit represented by the formula (a4-4) include the following monomers.

  When the resin (A) has the 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%.

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

In the resist composition, the content of the resin (A) is preferably 80% by mass or more, more preferably 82% by mass or more, still more preferably 85% by mass or more, particularly preferably based on the solid content of the resist composition. 90% by mass or more. Moreover, 99 mass% or less is preferable, More preferably, it is 98 mass% or less, More preferably, it is 97 mass% or less, Most preferably, it is 96 mass% or less.
In the resist composition of the present invention, when the content of the resin (A) is within the above range, the resist pattern collapse resistance is good.

<Method for producing resin (A)>
The resin (A) can be produced by polymerizing the monomer (a1) and the monomer (s) used as necessary by a known polymerization method (for example, radical polymerization method). The content rate of each structural unit which resin (A) has can be adjusted with the usage-amount of the monomer used for copolymerization.

  The weight average molecular weight of the resin (A) is preferably 2,500 or more (more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less). In addition, the weight average molecular weight here is calculated | required as a conversion value of a standard polystyrene reference | standard by gel permeation chromatography analysis. Detailed analysis conditions for this analysis are described in the examples herein.

<Resin other than resin (A)>
The resist composition of the present invention may contain a resin other than the resin (A). An example of such a resin is a resin composed of only the structural unit (s).
Especially, as resin other than resin (A), resin (henceforth "resin (X)") which has structural unit (a4) is preferable. In the resin (X), the content ratio of the structural unit (a4) is preferably 80 mol% or more, more preferably 85 mol% or more, and still more preferably 90 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 3 to 50 parts by mass with respect to 100 parts by mass of the resin (A). Preferably it is 4-40 mass parts, Most preferably, it is 5-30 mass parts.

  The resin content in the resist composition is preferably 80% by mass or more and 99% by mass or less with respect to the solid content of the resist composition.

The resist composition of the present invention preferably further contains a solvent (D), a basic compound (C) and the like.
<Solvent (D)>
The content of the solvent (D) is, for example, 90% by mass or more in the resist composition, preferably 92% by mass or more, more preferably 94% by mass or more, for example 99.9% by mass or less, preferably 99% by mass or less. It is. The content rate of a solvent (D) can be measured with well-known analysis means, such as a liquid chromatography or a gas chromatography, for example.

  Examples of the solvent (D) 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 And esters such as ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; A solvent (D) may contain individually by 1 type and may contain 2 or more types.

<Basic compound (C)>
The basic compound (C) is preferably a basic nitrogen-containing organic compound, and examples thereof include amines and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines. The basic compound (C) is preferably a compound represented by any one of the formulas (C1) to (C8) and (C1-1), more preferably represented by the formula (C1-1). The compound which is made is mentioned.

[In formula (C1), R ^c1 , R ^c2 and R ^c3 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 5 to 10 carbon atoms, or 6 to 6 carbon atoms. 10 represents an aromatic hydrocarbon group, and the hydrogen atom contained in the alkyl group and the alicyclic hydrocarbon group may be substituted with a hydroxy group, an amino group or an alkoxy group having 1 to 6 carbon atoms, The hydrogen atom contained in the aromatic hydrocarbon group is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 5 to 10 carbon atoms, or a carbon atom having 6 to 10 carbon atoms. It may be substituted with an aromatic hydrocarbon group. ]

[In Formula (C1-1), R ^c2 and R ^c3 represent the same meaning as described above.
R ^c4 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 5 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.
m3 represents an integer of 0 to 3, and when m3 is 2 or more, the plurality of R ^c4 are the same or different. ]

[In Formula (C2), Formula (C3) and Formula (C4), R ^c5 , R ^c6 , R ^c7 and R ^c8 each independently represent the same meaning as R ^c1 .
R ^c9 represents an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 3 to 6 carbon atoms, or an alkanoyl group having 2 to 6 carbon atoms.
n3 represents an integer of 0 to 8, and when n3 is 2 or more, the plurality of R ^c9 are the same or different. ]

[In Formula (C5) and Formula (C6), R ^c10 , R ^c11 , R ^c12 , R ^c13 and R ^c16 each independently represent the same meaning as R ^c1 .
R ^c14 , R ^c15 and R ^c17 each independently represent the same meaning as R ^c4 .
o3 and p3 each independently represents an integer of 0 to 3, and when o3 is 2 or more, the plurality of R ^c14 are the same or different, and when p3 is 2 or more, the plurality of R ^c15 are the same or Different.
L ^c1 represents an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

Wherein (C7) and formula ^{(C8), R c18, R} c19 and R ^c20 in each occurrence independently represent the same meaning as R ^c4.
q3, r3 and s3 each independently represent an integer of 0 to 3, and when q3 is 2 or more, the plurality of R ^c18 are the same or different, and when r3 is 2 or more, the plurality of R ^c19 are the same. Or when different and when s3 is 2 or more, the plurality of R ^c20 are the same or different.
L ^c2 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

In formula (C1) to formula (C8) and formula (C1-1), the alkyl group, alicyclic hydrocarbon group, aromatic hydrocarbon group, alkoxy group, alkanediyl group are the same as those described above. Is mentioned.
Examples of the alkanoyl group include acetyl group, 2-methylacetyl group, 2,2-dimethylacetyl group, propionyl group, butyryl group, isobutyryl group, pentanoyl group, and 2,2-dimethylpropionyl group.

  Examples of the compound represented by the formula (C1) 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, tri Pentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyl Hexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonyl Amine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2- Examples include diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, and preferably diisopropyl. Piruanirin. Particularly preferred include 2,6-diisopropylaniline.

Examples of the compound represented by the formula (C2) include piperazine.
Examples of the compound represented by the formula (C3) include morpholine.
Examples of the compound represented by the formula (C4) include piperidine and hindered amine compounds having a piperidine skeleton described in JP-A No. 11-52575.
Examples of the compound represented by the formula (C5) include 2,2′-methylenebisaniline.
Examples of the compound represented by the formula (C6) include imidazole and 4-methylimidazole.
Examples of the compound represented by the formula (C7) include pyridine and 4-methylpyridine.
Examples of the compound represented by the formula (C8) include 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′-dipiconylamine, bipyridine and the like.

  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 content of the basic compound (C) in the solid content of the resist composition is preferably about 0.01 to 5% by mass, more preferably about 0.01 to 3% by mass, and particularly preferably 0.8. It is about 01 to 1% by mass.

<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 (I) used as an acid generator, a solvent (D), an acid generator (B), a basic compound (C) and other compounds used as necessary. It can be prepared by mixing component (F). The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select an appropriate temperature range from the range of 10-40 degreeC according to the kind etc. of resin etc., the solubility with respect to solvents (D), 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) The process of heating the composition layer after exposure, (5) The process of developing the composition layer after a heating is included.

  The resist composition can be applied onto the substrate by a commonly used apparatus such as a spin coater.

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., for example, and the heating time is preferably 10 to 180 seconds, for example. The pressure during drying under reduced pressure is preferably about 1 to 1.0 × 10 ⁵ Pa.

The obtained composition layer is usually exposed using an exposure machine. The exposure machine may be an immersion exposure machine. At this time, exposure is usually performed through a mask corresponding to a required pattern. 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.

  The composition layer after exposure is subjected to heat treatment (so-called post-exposure baking) in order to promote the deprotection reaction of the resin (A). 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.

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 a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure, or a resist composition for EUV exposure, particularly a liquid. It is suitable as a resist composition for immersion exposure and 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 structure of the compound was confirmed by MASS (LC: Agilent 1100 type, MASS: Agilent LC / MSD type or LC / MSD TOF type).
The composition ratio of the resin (A) (copolymerization ratio of the structural unit derived from each monomer used for the production of the resin (A) to the resin (A)) is the amount of unreacted monomer in the reaction liquid after the polymerization is finished. It measured using the chromatography, and computed by calculating | requiring the monomer amount consumed by superposition | polymerization from the obtained result.
The weight average molecular weight is a value determined by gel permeation chromatography under the following conditions.
Apparatus: HLC-8120GPC type (manufactured by Tosoh Corporation)
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)

Example 1 [Synthesis of salt represented by formula (I-56)]

  58.1 parts of a compound represented by the formula (I-56-a), 208.3 parts of N-methylpiperidine and 870 parts of dioxane were charged into a reactor and stirred at 40 ° C. for 30 minutes. Thereafter, 403.7 parts of a compound represented by the formula (I-56-b) was added and stirred at 40 ° C. for 40 hours. After adding 64 parts of methanol to the resulting reaction mixture and stirring, the supernatant was recovered. After the collected supernatant was concentrated, 1500 parts of methyl isobutyl ketone and 750 parts of ion-exchanged water were added to the resulting concentrate and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 750 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This water washing operation was further repeated 10 times. After concentrating the collected organic layer, the resulting concentrate is subjected to column fractionation (column fractionation conditions, stationary phase: silica gel 60-200 mesh, developed by Merck & Co., Ltd., developing solvent: toluene) to obtain the formula (I-56 15.7 parts of the compound represented by -c) were obtained.

  3.58 parts of the compound represented by the formula (I-56-c) and 26.7 parts of acetonitrile were charged into a reactor and stirred at 23 ° C. for 30 minutes. Thereafter, 1.76 parts of a compound represented by the formula (I-56-d) was added, and the mixture was stirred at 23 ° C. for 12 hours. The obtained reaction mixture was filtered to obtain 4.00 parts of the salt represented by the formula (I-56-e).

1.00 parts of a salt represented by the formula (I-56-f) obtained by the method described in JP-A-2008-209917, and a salt 1.47 represented by the formula (I-56-e) Part, chloroform 10 parts and ion-exchanged water 5 parts were charged in a reactor and stirred at 23 ° C. for 15 hours. Since the obtained reaction liquid was separated into two layers, the chloroform layer was separated and taken out, and 5 parts of ion-exchanged water was further added to the chloroform layer and washed with water. This operation was repeated 5 times. The chloroform layer was concentrated, 10 parts of tert-butyl methyl ether was added to the resulting residue, the mixture was stirred at 23 ° C. for 30 minutes, and then filtered to obtain the salt 1.62 represented by the formula (I-56). Got a part.
MASS (ESI (+) Spectrum): M ⁺ 374.2
MASS (ESI (−) Spectrum): M ⁻ 339.1

Example 2 [Synthesis of salt represented by formula (I-62)]

  7.21 parts of a compound represented by the formula (I-62-a), 15.62 parts of N-methylpiperidine and 108.2 parts of dioxane were charged into a reactor and stirred at 40 ° C. for 30 minutes. Thereafter, 30.28 parts of a compound represented by the formula (I-62-b) was added and stirred at 40 ° C. for 40 hours. To the resultant reaction mixture, 4.8 parts of methanol was added and stirred, followed by filtration. After concentrating the collected filtrate, 120 parts of methyl isobutyl ketone and 70 parts of ion-exchanged water were added to the resulting concentrate and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 70 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This water washing operation was further repeated 13 times. After the collected organic layer was concentrated, the obtained concentrate was subjected to column fractionation (column fractionation conditions, stationary phase: silica gel 60-200 mesh, developed by Merck & Co., Ltd., developing solvent: toluene) to obtain the formula (I-62 4.00 parts of a compound represented by -c) were obtained.

  A compound represented by the formula (I-62-c) (3.09 parts) and acetonitrile (22.5 parts) were charged into a reactor and stirred at 23 ° C. for 30 minutes. Thereafter, 1.41 parts of a compound represented by the formula (I-62-d) was added and stirred at 23 ° C. for 20 hours. The obtained reaction mixture was filtered to obtain 3.75 parts of the salt represented by the formula (I-62-e).

1.00 parts of the salt represented by the formula (I-62-f) obtained by the method described in JP-A-2008-209917, and the salt 1.55 represented by the formula (I-62-e) Part, chloroform 10 parts and ion-exchanged water 5 parts were charged in a reactor and stirred at 23 ° C. for 15 hours. Since the obtained reaction liquid was separated into two layers, the chloroform layer was separated and taken out, and 5 parts of ion-exchanged water was further added to the chloroform layer and washed with water. This operation was repeated 5 times. The chloroform layer was concentrated, 10 parts of tert-butyl methyl ether was added to the resulting residue, the mixture was stirred at 23 ° C. for 30 minutes, and then filtered to obtain a salt 1.72 represented by the formula (I-62). Got a part.
MASS (ESI (+) Spectrum): M ⁺ 402.2
MASS (ESI (−) Spectrum): M ⁻ 339.1

Example 3 [Synthesis of salt represented by formula (I-50)]

  5.2 parts of a compound represented by the formula (I-50-c) and 54.5 parts of acetonitrile were charged into a reactor and stirred at 23 ° C. for 30 minutes. Then, 3.3 parts of a compound represented by the formula (I-50-d) was added and stirred at 23 ° C. for 20 hours. The obtained reaction mixture was filtered to obtain 5.25 parts of the salt represented by the formula (I-50-e).

1.00 parts of the salt represented by the formula (I-50-f) obtained by the method described in JP-A-2008-209917, and the salt 1.08 represented by the formula (I-50-e) Part, chloroform 10 parts and ion-exchanged water 5 parts were charged in a reactor and stirred at 23 ° C. for 15 hours. Since the obtained reaction liquid was separated into two layers, the chloroform layer was separated and taken out, and 5 parts of ion-exchanged water was further added to the chloroform layer and washed with water. This operation was repeated 5 times. The chloroform layer was concentrated, 10 parts of tert-butyl methyl ether was added to the resulting residue, and the mixture was stirred at 23 ° C. for 30 minutes, and then filtered to obtain 0.59 of the salt represented by the formula (I-50). Got a part.
MASS (ESI (+) Spectrum): M ⁺ 232.1
MASS (ESI (−) Spectrum): M ⁻ 339.1

Example 4 [Synthesis of salt represented by formula (I-2)]

  A reactor was charged with 6.21 parts of a compound represented by the formula (I-2-a), 40.37 parts of a compound represented by the formula (I-2-b) and 139.7 parts of toluene. For 30 minutes. Thereafter, 21.25 parts of triethylamine was added dropwise and stirred at 23 ° C. for 18 hours. To the obtained reaction mixture, 200 parts of ethyl acetate and 150 parts of ion-exchanged water were added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 150 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This washing operation was further repeated 5 times. After the collected organic layer was concentrated, the obtained concentrate was subjected to column fractionation (column fractionation conditions, stationary phase: silica gel 60-200 mesh manufactured by Merck & Co., Ltd., developing solvent: ethyl acetate / n-heptane = 1/1 volume. Ratio) to obtain 4.28 parts of a compound represented by the formula (I-2-c).

  3.65 parts of the compound represented by the formula (I-2-c) and 18.2 parts of acetonitrile were charged into a reactor and stirred at 23 ° C. for 30 minutes. Thereafter, 2.12 parts of the compound represented by the formula (I-2-d) was added and stirred at 23 ° C. for 20 hours. The obtained reaction mixture was filtered to obtain 3.61 parts of the salt represented by the formula (I-2-e).

1.00 parts of the salt represented by the formula (I-2-f) obtained by the method described in JP-A-2008-209917, and the salt 1.32 represented by the formula (I-2-e) Part, chloroform 10 parts and ion-exchanged water 5 parts were charged in a reactor and stirred at 23 ° C. for 15 hours. Since the obtained reaction liquid was separated into two layers, the chloroform layer was separated and taken out, and 5 parts of ion-exchanged water was further added to the chloroform layer and washed with water. This operation was repeated 5 times. The chloroform layer was concentrated, 10 parts of tert-butyl methyl ether was added to the resulting residue, the mixture was stirred at 23 ° C. for 30 minutes, and then filtered to give the salt represented by formula (I-2) 1.12. Got a part.
MASS (ESI (+) Spectrum): M ⁺ 320.1
MASS (ESI (−) Spectrum): M ⁻ 339.1

Example 5 [Synthesis of salt represented by formula (I-98)]

  12.02 parts of a compound represented by the formula (I-98-a), 9.49 parts of pyridine and 129.1 parts of tetrahydrofuran were charged into a reactor, and stirred at 40 ° C. for 30 minutes. Thereafter, 24.22 parts of a compound represented by the formula (I-98-b) was added and stirred at 40 ° C. for 40 hours. To the resultant reaction mixture, 3.8 parts of methanol was added and stirred, and then filtered. After the collected filtrate was concentrated, 200 parts of ethyl acetate and 75 parts of ion-exchanged water were added to the obtained concentrate, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 75 parts of ion exchange water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This washing operation was repeated three more times. After the collected organic layer was concentrated, the obtained concentrate was subjected to column fractionation (column fractionation conditions stationary phase: silica gel 60-200 mesh manufactured by Merck & Co., Ltd. developing solvent: toluene / ethyl acetate = 2/1 volume ratio). As a result, 9.40 parts of a compound represented by the formula (I-98-c) was obtained.

  3.86 parts of the compound represented by the formula (I-98-c) and 26.3 parts of acetonitrile were charged into a reactor and stirred at 23 ° C. for 30 minutes. Thereafter, 1.41 parts of a compound represented by the formula (I-98-d) was added, and the mixture was stirred at 23 ° C. for 20 hours. The obtained reaction mixture was filtered to obtain 2.02 parts of the salt represented by the formula (I-98-e).

1.00 parts of the salt represented by the formula (I-98-f) obtained by the method described in JP 2008-209917 A, and the salt 1.82 represented by the formula (I-98-e) Part, chloroform 10 parts and ion-exchanged water 5 parts were charged in a reactor and stirred at 23 ° C. for 15 hours. Since the obtained reaction liquid was separated into two layers, the chloroform layer was separated and taken out, and 5 parts of ion-exchanged water was further added to the chloroform layer and washed with water. This operation was repeated 5 times. The chloroform layer was concentrated, 10 parts of tert-butyl methyl ether was added to the obtained residue, and the mixture was stirred at 23 ° C. for 30 minutes, and then filtered to obtain the salt 1.01 represented by the formula (I-98). Got a part.
MASS (ESI (+) Spectrum): M ⁺ 498.3
MASS (ESI (−) Spectrum): M ⁻ 339.1

Example 6 [Synthesis of salt represented by formula (I-92)]

  37.45 parts of the compound represented by the formula (I-92-a), 18.27 parts of pyridine and 374.5 parts of tetrahydrofuran were charged into a reactor and stirred at 23 ° C. for 30 minutes. Thereafter, 44.41 parts of a compound represented by the formula (I-92-b) was added, and the mixture was stirred at 23 ° C. for 14 hours. The obtained reaction mixture was filtered, and the collected filtrate was concentrated. To the obtained concentrate, 1500 parts of ethyl acetate and 400 parts of ion-exchanged water were added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 400 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This washing operation was repeated three more times. After the collected organic layer was concentrated, the obtained concentrate was subjected to column fractionation (column fractionation conditions stationary phase: silica gel 60-200 mesh manufactured by Merck & Co., Ltd. Developing solvent: n-heptane / ethyl acetate = 2/1 volume. To obtain 41.2 parts of a compound represented by the formula (I-92-c).

  6.16 parts of the compound represented by the formula (I-92-c) and 44.0 parts of acetonitrile were charged into a reactor and stirred at 23 ° C. for 30 minutes. Thereafter, 2.65 parts of the compound represented by the formula (I-92-d) was added and stirred at 23 ° C. for 20 hours. The obtained reaction mixture was filtered to obtain 5.85 parts of the salt represented by the formula (I-92-e).

1.00 parts of the salt represented by the formula (I-92-f) obtained by the method described in JP 2008-209917 A, and the salt 2.23 represented by the formula (I-92-e) Part, chloroform 20 parts and ion-exchanged water 5 parts were charged into a reactor and stirred at 23 ° C. for 15 hours. Since the obtained reaction solution was separated into two layers, the chloroform layer was separated and taken out, and 10 parts of ion-exchanged water was further added to the chloroform layer and washed with water. This operation was repeated 5 times. The chloroform layer was concentrated, 10 parts of tert-butyl methyl ether was added to the resulting residue, the mixture was stirred at 23 ° C. for 30 minutes, and then filtered to obtain the salt 1.68 represented by the formula (I-92). Got a part.
MASS (ESI (+) Spectrum): M ⁺ 648.3
MASS (ESI (−) Spectrum): M ⁻ 339.1

Synthesis of Resin (A) The compounds used for the synthesis of resin (A) are shown below.

  Hereinafter, these compounds are referred to as “monomer (a1-1-2)” or the like according to the formula number.

Synthesis Example 1 [Synthesis of Resin A1]
As the monomer, using monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-3), monomer (a3-2-1) and monomer (a3-1-1), The molar ratio [monomer (a1-1-3): monomer (a1-2-9): monomer (a2-1-3): monomer (a3-2-1)): monomer (a3-1-1)] However, it mixed so that it might become 45: 14: 2.5: 22: 16.5, and 1.5 mass times propylene glycol monomethyl ether acetate of the total monomer amount was added, and it was set as the solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 0.95 mol% and 2.85 mol%, respectively, based on the total monomer amount, and these were added at 73 ° C. Heated for about 5 hours. 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 resin obtained was dissolved again in propylene glycol monomethyl ether acetate, and the resulting solution was poured into a methanol solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and the weight-average molecular weight was 7. 9 × 10 ³ resin A1 was obtained with a yield of 73%. This resin A1 has the following structural units.

Synthesis Example 2 [Synthesis of Resin A2]
As the monomer, using monomer (a1-1-3), monomer (a1-3-1), monomer (a2-1-3), monomer (a3-2-1) and monomer (a3-1-1), The molar ratio [monomer (a1-1-3): monomer (a1-3-1): monomer (a2-1-3): monomer (a3-2-1)): monomer (a3-1-1)] However, it mixed so that it might become 45: 14: 2.5: 22: 16.5, and 1.5 mass times propylene glycol monomethyl ether acetate of the total monomer amount was added, and it was set as the solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 0.95 mol% and 2.85 mol%, respectively, based on the total monomer amount, and these were added at 73 ° C. Heated for about 5 hours. 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 resin obtained was dissolved again in propylene glycol monomethyl ether acetate, and the resulting solution was poured into a methanol solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and the weight-average molecular weight was 7. 6 × 10 ³ resin A2 was obtained with a yield of 68%. This resin A2 has the following structural units.

Synthesis Example 3: [Synthesis of Resin A3]
Monomer (1-1-2), monomer (a2-1-1) and monomer (a3-1-1) are mixed in a molar ratio [monomer (1-1-2): monomer (a2-1-1): Monomer (a3-1-1)] was mixed so as to be 50:25:25, and 1.5 mass times dioxane was further mixed with respect to the total mass of all monomers. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators in proportions of 1 mol% and 3 mol%, respectively, with respect to the total number of moles of all monomers. Then, this was heated at 80 ° C. for about 8 hours to carry out polymerization. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. Again, the obtained resin is dissolved in dioxane, poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and recovered three times for reprecipitation purification. A resin A3 having a weight average molecular weight of about 9.2 × 10 ³ was obtained in a yield of 60%. This resin A3 has structural units derived from the following monomers.

Synthesis Example 4 [Synthesis of Resin A4]
Monomer (a1-1-2), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-2-3) and monomer (a3-1-1) are mixed in a molar ratio [ Monomer (a1-1-2): monomer (a1-2-3): monomer (a2-1-1): monomer (a3-2-3): monomer (a3-1-1)] is 30:14 : 6: 20: 30 The mixture was mixed and 1.5 mass times dioxane of the total monomer amount was added to make 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 again dissolved in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 7.2. A × 10 ³ copolymer A4 was obtained with a yield of 78%. This resin A4 has the following structural units.

Synthesis Example 5 [Synthesis of Resin A5]
Monomer (a1-1-2), monomer (a1-3-1), monomer (a2-1-1), monomer (a3-2-3) and monomer (a3-1-1) are mixed in a molar ratio [ Monomer (a1-1-2): monomer (a1-3-1): monomer (a2-1-1): monomer (a3-2-3): monomer (a3-1-1)] is 30:14 : 6: 20: 30 The mixture was mixed and 1.5 mass times dioxane of the total monomer amount was added to make 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 again dissolved in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 7.2. A × 10 ³ copolymer A5 was obtained with a yield of 78%. This resin A5 has the following structural units.

Synthesis Example 6 [Synthesis of Resin X1]
Monomer (a4-1-7) was used as a monomer, and 1.5 mass times dioxane of 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 methanol / water mixed solvent to precipitate the resin, and this resin was filtered.
The resin thus obtained was dissolved again in dioxane, and the solution obtained by pouring the solution into a methanol / water mixed solvent was precipitated twice, and the resin was filtered twice to perform the reprecipitation operation twice. 8 × 10 ⁴ of resin X1 was obtained with a yield of 77%. This resin X1 has the following structural units.

<Preparation of resist composition>
As shown in Table 4, each component was mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

<Resin>
A1: Resin A1
A2: Resin A2
A3: Resin A3
A4: Resin A4
A5: Resin A5
X1: Resin X1

<Acid generator>
I-56: salt represented by formula (I-56) I-62: salt represented by formula (I-62) I-50: salt represented by formula (I-50) I-2: formula Salt represented by (I-2) I-98: Salt represented by formula (I-98) I-92: Salt represented by formula (I-92) B1-3: JP 2010-152341 A Synthesis according to the example of the publication

Z1: Synthesis according to the example of JP-A-2003-342254

<Basic compound: Quencher>
C1: 2,6-diisopropylaniline (manufactured by 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

Examples 7 to 17 and Comparative Example 1
<Manufacture of positive resist pattern>
An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] was applied onto a 12-inch silicon wafer and baked at 205 ° C. for 60 seconds to obtain a thickness of 78 nm. An organic antireflection film was formed.
The resist composition was spin-coated on the organic antireflection film so that the film thickness after drying (pre-baking) was 85 nm.
The obtained silicon wafer was pre-baked on a direct hot plate at a temperature described in the “PB” column of Table 4 for 60 seconds to form a composition layer on the wafer. An ArF excimer laser stepper for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light] is applied to the composition layer formed on the silicon wafer in this manner. Using a mask for forming an and-space pattern (pitch 100 nm / line width 50 nm), exposure was carried out while changing the exposure amount stepwise. Note that ultrapure water was used as the immersion medium.
After exposure, post-exposure baking was performed for 60 seconds on the hot plate at the temperature indicated in the “PEB” column of Table 4, and further paddled at 23 ° C. for 60 seconds with an aqueous 2.38% tetramethylammonium hydroxide solution. The resist pattern was obtained by developing by the method.

  In the obtained resist pattern, the exposure amount at which the line pattern width was 50 nm was defined as the effective sensitivity.

<Pattern collapse evaluation (PCM) evaluation>
Using a mask for forming a 50 nm 1: 1 line and space pattern (pitch 100 nm / line 50 nm), the line pattern formed with an exposure amount higher than the effective sensitivity was observed. A case where pattern disappearance due to falling or peeling is not observed even if the line width of the pattern transferred to the substrate by exposure becomes thinner than 45 nm, and a case where pattern disappearance due to falling or peeling is observed even when the line width is 45 nm or more. It was. The results are shown in Table 5. The numbers in parentheses indicate the minimum line width (nm) of the resist pattern in which no pattern disappearance is observed.

Examples 18 to 26 and Comparative Example 2
<Manufacture of negative resist pattern>
An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] was applied onto a 12-inch silicon wafer, and baked under the conditions of 205 ° C. and 60 seconds, whereby an organic layer having a thickness of 78 nm was obtained. An antireflection film was formed. Next, the resist composition was spin-coated on the organic antireflection film so that the film thickness of the composition layer after drying (pre-baking) was 100 nm. After coating, the composition layer was formed on the silicon wafer by pre-baking on a direct hot plate for 60 seconds at the temperature described in the “PB” column of Table 4.
The composition layer formed on the silicon wafer was subjected to an immersion exposure ArF excimer laser stepper [XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized illumination], and a line and space pattern. Using a mask for forming (pitch 90 nm / line width 45 nm), the exposure was changed in stages and exposed. Note that ultrapure water was used as the immersion medium.
After exposure, post-exposure baking was performed for 60 seconds on the hot plate at the temperature described in the “PEB” column of Table 4. 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 obtained resist pattern, an exposure amount at which the line width and space width of the line and space pattern were 1: 1 was defined as effective sensitivity.

<Pattern collapse evaluation (PCM) evaluation>
When the obtained resist pattern was observed with a scanning electron microscope and the pattern pattern disappeared due to falling or peeling was not observed in the line pattern formed with an exposure amount less than the effective sensitivity, it was formed with an exposure amount less than the effective sensitivity. The case where pattern disappearance due to falling or peeling was observed also in the line pattern was marked as x. The results are shown in Table 6. The line width of the line pattern becomes narrower as the exposure amount is smaller, and the pattern disappears more easily. The numbers in parentheses indicate the minimum line width (nm) of the resist pattern in which no pattern disappearance is observed.

  According to the salt of the present invention, a resist pattern having excellent pattern collapse resistance can be produced from a resist composition containing the salt, which is useful for fine processing of semiconductors.

Claims (7)

A salt represented by the formula (I).

[In the formula (I),
R ^s1 , R ^s2 , R ^s5 and R ^s6 are each independently an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms. And —CH ₂ — contained in the alicyclic hydrocarbon group may be replaced by —O— or —CO—. R ^s1 and R ^s2 may together form a 3- to 12-membered ring with the sulfur atom to which they are bonded, and R ^s5 and R ^s6 are the sulfur to which they are bonded together. A 3- to 12-membered ring may be formed together with the atom, and —CH ₂ — contained in these rings may be replaced with —O— or —CO—.
R ^s3 and R ^s4 each independently represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
L ^s1 represents a single bond or a divalent hydrocarbon group having 1 to 36 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
R ^s7 , R ^s8 , R ^s10 and R ^s11 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^s2 and L ^s3 each independently represent a single bond or a divalent saturated hydrocarbon group having 1 to 15 carbon atoms which may have a substituent.
X ^s1 and X ^s2 represent —O—CO— or —O—.
R ^s9 and R ^s12 each independently represents an optionally substituted saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group is —O— , —SO ₂ — or —CO— may be substituted. ] The salt according to claim 1, wherein L ^s1 is a single bond, a carbonyl group, a phenylene group, an alkanediyl group having 1 to 18 carbon atoms, or a group represented by the formula (xs1).

[In the formula (xs1), L ^s4 represents a divalent hydrocarbon group having 1 to 32 carbon atoms. ] The salt according to claim 1 or 2, wherein R ^s9 and R ^s12 are a group represented by the formula (I-A1-1).

[In Formula (I-A1-1), W ^s1 represents an alicyclic hydrocarbon group having 3 to 24 carbon atoms which may have a substituent.
L ^s21 represents a C1-C21 divalent saturated hydrocarbon group which may have a single bond or a substituent.
However, the upper limit of the total carbon number of W ^s1 and L ^s21 is 24.
Note that —CH ₂ — contained in the alicyclic hydrocarbon group of W ^s1 may be replaced by —O—, —SO ₂ —, or —CO—. ]   The acid generator containing the salt in any one of Claims 1-3.   A resist composition comprising the acid generator according to claim 4 and a resin having an acid labile group.   Furthermore, the resist composition of Claim 5 containing a basic compound. (1) The process of apply | coating the resist composition of Claim 5 or 6 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: