JP2018115149A - Salt, acid generator, resist composition, and method for producing resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a salt and a resist composition capable of producing a resist pattern having good CD uniformity.SOLUTION: There are provided: the salt having a group represented by formula (aa1); an acid generator containing the salt; and the resist composition containing the acid generator. [In the formula, Xand Xeach represent an oxygen atom or a sulfur atom; ring Wrepresents an alicyclic hydrocarbon group, provided that a hydrogen atom in the alicyclic hydrocarbon group may be substituted with a hydroxy group, an alkyl group, an alkoxy group, an alkoxycarbonyl group, or the like; Land Leach represent a single bond or a hydrocarbon group; Rand Reach represent an alicyclic hydrocarbon group which may have a substituent, provided that -CH- contained in the alicyclic hydrocarbon group may be substituted with -O-, -S-, -S(O)-, -CO-, or the like; and * represents a bond.]SELECTED DRAWING: None

Description

  The present invention relates to a salt, an acid generator, 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 an acid generator.
Patent Document 2 describes a resist composition containing a salt represented by the following formula as an acid generator.

JP 2011-37837 A JP 2011-246444 A

  In the resist composition containing the above salt, the CD uniformity (CDU) of the resulting resist pattern may not always be satisfied.

The present invention includes the following inventions.
[1] A salt having a group represented by the formula (aa1).
[In the formula (aa1),
X ^a and X ^b each independently represent an oxygen atom or a sulfur atom.
Ring W ¹ represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group includes a hydroxy group, an alkyl group having 1 to 12 carbon atoms, and 1 to 1 carbon atoms. 12 alkoxy groups having 2 to 13 carbon atoms, alkylcarbonyl groups having 2 to 13 carbon atoms, alkylcarbonyloxy groups having 2 to 13 carbon atoms, alicyclic hydrocarbon groups having 3 to 12 carbon atoms, carbon It may be substituted with an aromatic hydrocarbon group of several 6 to 10 or a combination thereof.
L ¹ and L ² each independently represent a single bond or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group is —O—, —S—, —CO—. Alternatively, it may be replaced by -S (O) _2- .
R ¹ and R ² each independently represents a C 3-18 alicyclic hydrocarbon group which may have a substituent, and —CH ₂ — contained in the alicyclic hydrocarbon group is: -O-, -S-, -CO- or -S (O) _2- may be substituted.
* Represents a bond. ]
[2] The salt according to [1], comprising an anion having a group represented by the formula (aa1) and a cation.
[3] The salt according to [2], wherein the anion having a group represented by the formula (aa1) is an anion having a group represented by the formula (aa1) and a sulfonate.
[4] The salt according to [3], wherein the anion having a group represented by the formula (aa1) and a sulfonate is a salt having an anion represented by the formula (aa2).
[In the formula (aa2),
X ^a , X ^b , L ¹ , L ² , R ¹ , R ² and ring W ¹ represent the same meaning as described above.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced by —O— or —CO—, and the saturated The hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group. ]
[5] Ring W ¹ is a ring represented by formula (w1-1), a ring represented by formula (w1-2), a ring represented by formula (w1-3), or formula (w1-6) The salt in any one of [1]-[4] which is a ring represented by these.
[In Formula (w1-1), Formula (w1-2) and Formula (w1-3),
The hydrogen atom contained in the ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic group having 6 to 10 carbon atoms. It may be substituted with a hydrocarbon group. ]
[6] L ^b1 represents # —CO—O— (CH ₂ ) _t — (t represents an integer of 0 to 6. # represents a bond to —C (Q ¹ ) (Q ² ) —. The salt according to [4] or [5], which represents a hand.
[7] An acid generator containing the salt according to any one of [1] to [6].
[8] A resist composition comprising the acid generator according to [7] and a resin having an acid labile group.
[9] The resist composition according to [8], further comprising a salt that generates an acid having a lower acidity than an acid generated from an acid generator.
[10] (1) A step of applying the resist composition according to [8] or [9] on a substrate,
(2) A step of drying the composition after application to form a composition layer,
(3) a step of exposing the composition layer;
(4) A method for producing a resist pattern, comprising: a step of heating the composition layer after exposure; and (5) a step of developing the composition layer after heating.

  Provided are a salt capable of producing a resist pattern having good CD uniformity (CDU) and a resist composition containing the salt.

In this specification, the term “(meth) acrylic monomer” refers to a monomer having a structure of “CH ₂ ═CH—CO—” and a monomer having a structure of “CH ₂ ═C (CH ₃ ) —CO—”. Means at least one selected from the group consisting of Similarly, “(meth) acrylate” and “(meth) acrylic acid” are respectively “at least one selected from the group consisting of acrylate and methacrylate” and “at least one selected from the group consisting of acrylic acid and methacrylic acid”. "Means. Moreover, in the group described in the present specification, any group that can take both a linear structure and a branched structure may be used. When stereoisomers exist, all stereoisomers are included.
In the present specification, the “solid content of the resist composition” means the total of components excluding the solvent (E) described later from the total amount of the resist composition.

[Salt (aa)]
The salt of the present invention is a salt having a group represented by the following formula (aa1) (hereinafter sometimes referred to as “salt (aa)”).
[In the formula (aa1),
X ^a and X ^b each independently represent an oxygen atom or a sulfur atom.
Ring W ¹ represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group includes a hydroxy group, an alkyl group having 1 to 12 carbon atoms, and 1 to 1 carbon atoms. 12 alkoxy groups having 2 to 13 carbon atoms, alkylcarbonyl groups having 2 to 13 carbon atoms, alkylcarbonyloxy groups having 2 to 13 carbon atoms, alicyclic hydrocarbon groups having 3 to 12 carbon atoms, carbon It may be substituted with an aromatic hydrocarbon group of several 6 to 10 or a combination thereof.
L ¹ and L ² each independently represent a single bond or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group is —O—, —S—, —CO—. Alternatively, it may be replaced by -S (O) _2- .
R ¹ and R ² each independently represents a C 3-18 alicyclic hydrocarbon group which may have a substituent, and —CH ₂ — contained in the alicyclic hydrocarbon group is: -O-, -S-, -CO- or -S (O) _2- may be substituted.
* Represents a bond. ]

X ^a and X ^b are preferably the same atom, and more preferably an oxygen atom.

The alicyclic hydrocarbon group represented by ring W ¹ may be either monocyclic or polycyclic, for example, a ring represented by formula (w1-1) to formula (w1-11). Group derived from.
Ring W ¹ is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms. The ring represented by formula (w1-1), the ring represented by formula (w1-2), and formula (w1) -3) or a ring represented by formula (w1-6) is more preferred, and a ring represented by formula (w1-1) is more preferred.
[In Formula (w1-1)-Formula (w1-11),
The hydrogen atom contained in the ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 13 carbon atoms, an alkylcarbonyl group having 2 to 13 carbon atoms, carbon The alkylcarbonyloxy group having 2 to 13 carbon atoms, the alicyclic hydrocarbon group having 3 to 12 carbon atoms, or the aromatic hydrocarbon group having 6 to 10 carbon atoms may be substituted. ]

Examples of the alkyl group having 1 to 12 carbon atoms that is a substituent of the ring W ¹ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, and an undecyl group. Group, dodecyl group and the like.
Examples of the alkoxy group having 1 to 12 carbon atoms which is a substituent of the ring W ¹ include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, octyloxy group, 2-ethylhexyloxy group, nonyloxy Group, decyloxy group, undecyloxy group, dodecyloxy group and the like.
Ring W ¹ of a substituted alkoxycarbonyl group having a carbon number of 2 to 13, alkylcarbonyloxy group the alkyl group and 2 to 13 carbon atoms 2 to 13 carbon atoms, a carbonyl group in an alkyl group or an alkoxy group described above Or the group which the carbonyloxy group couple | bonded is mentioned.
Examples of the alicyclic hydrocarbon group having 3 to 12 carbon atoms which is a substituent of the ring W ¹ include the following groups. ** is a bond with a ring.
Examples of the aromatic hydrocarbon group having 6 to 10 carbon atoms that is a substituent of the ring W ¹ include a phenyl group, a naphthyl group, a tolyl group, a xylyl group, and a cyclohexylphenyl group.
Examples of the group in which the substituents of the ring W ¹ are combined include a group in which a hydroxy group and an alkyl group having 1 to 12 carbon atoms are combined, an alkyl group having 1 to 12 carbon atoms, and an aromatic hydrocarbon group having 6 to 10 carbon atoms. And a combination of these and the like.
Examples of the group in which the hydroxy group and the alkyl group having 1 to 12 carbon atoms are combined include a hydroxyalkyl group having 1 to 12 carbon atoms such as a hydroxymethyl group and a hydroxyethyl group.
Examples of the group in which an alkyl group having 1 to 12 carbon atoms and an aromatic hydrocarbon group having 6 to 10 carbon atoms are combined include an aralkyl group having 7 to 22 carbon atoms such as a benzyl group.

The hydrocarbon group represented by L ¹ and L ² has a total carbon number of 1 to 12, and may further have one or more substituents. Examples of the substituent include a hydroxy group, a cyano group, a carboxyl group, an alkoxy group having 1 to 12 carbon atoms, an alkylcarbonyl group having 2 to 13 carbon atoms, an alkylcarbonyloxy group having 2 to 13 carbon atoms, and these groups. The group which combined 2 or more types is mentioned.
Examples of the alkoxy group having 1 to 12 carbon atoms, the alkylcarbonyl group having 2 to 13 carbon atoms, and the alkylcarbonyloxy group are the same as those exemplified as the substituent of the ring W ¹ .
The hydrocarbon group represented by L ¹ and L ² is preferably an alkanediyl group. Examples of the alkanediyl group include methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, and the like. A chain alkanediyl group;
Ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane- Examples thereof include branched alkanediyl groups such as 1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group and 2-methylbutane-1,4-diyl group.
When —CH ₂ — contained in the hydrocarbon group represented by L ¹ and L ² is replaced by —O—, —S—, —CO— or —S (O) ₂ —, the carbon before the replacement The number is the total carbon number of the hydrocarbon group.

The alicyclic hydrocarbon group represented by R ¹ and R ² has a total carbon number of 3 to 18, and may further have one or more substituents. Examples of the substituent include a hydroxy group, a cyano group, a carboxyl group, an alkoxy group having 1 to 12 carbon atoms, an alkylcarbonyl group having 2 to 13 carbon atoms, an alkylcarbonyloxy group having 2 to 13 carbon atoms, and these groups. The group which combined 2 or more types is mentioned.
Examples of the alkoxy group having 1 to 12 carbon atoms, the alkylcarbonyl group having 2 to 13 carbon atoms, and the alkylcarbonyloxy group are the same as those exemplified as the substituent of the ring W ¹ .
—CH ₂ — contained in the alicyclic hydrocarbon group represented by R ¹ and R ² may be replaced by —O—, —S—, —CO— or —S (O) ₂ —.
When the alicyclic hydrocarbon group represented by R ¹ and R ² has a substituent, or —CH ₂ — contained in the alicyclic hydrocarbon group is —O—, —S—, —CO— or —. When S (O) ₂ — is replaced, the number of carbons before the replacement is defined as the total number of carbon atoms of the alicyclic hydrocarbon group.

The alicyclic hydrocarbon group represented by R ¹ and R ² is preferably a cyclohexyl group or an adamantyl group, and more preferably an adamantyl group.
The substituent that R ¹ or R ² has is preferably a group having a hydroxy group, and more preferably a hydroxy group.
Among the alicyclic hydrocarbon groups represented by R ¹ and R ² , among them, those having a substituent or —CH ₂ — contained in the alicyclic hydrocarbon group is —O—, —S—, —CO. -Or -S (O) _2- is preferably substituted, and is substituted with a hydroxy group or -CH _2- contained in an alicyclic hydrocarbon group is replaced with -CO-. More preferred.

  In the salt (aa), the anion may have a group represented by the formula (aa1), and the cation may have a group represented by the formula (aa1). The salt (aa) is preferably a salt composed of an anion having a group represented by the formula (aa1) and a cation, and a salt composed of an anion having a group represented by the formula (aa1) and an organic cation It is more preferable that

The anion having a group represented by the formula (aa1) is preferably a sulfonate anion having a group represented by the formula (aa1) and a sulfonate, and is preferably an anion represented by the formula (aa2). More preferred.
[In the formula (aa2),
X ^a , X ^b , L ¹ , L ² , R ¹ , R ² and ring W ¹ represent the same meaning as described above.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced by —O— or —CO—, and the saturated The hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group. ]

Examples of the perfluoroalkyl group represented by Q ¹ and Q ² include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluoro sec-butyl group, perfluorotert-butyl group, perfluoropentyl. Group and perfluorohexyl group.
Q ¹ and Q ² are preferably each independently a fluorine atom or a trifluoromethyl group, and both Q ¹ and Q ² are more preferably a fluorine atom.

Examples of the divalent saturated hydrocarbon group represented by L ^b1 include alkanediyl groups, monocyclic or polycyclic divalent alicyclic saturated hydrocarbon groups, and two or more of these groups. May be combined.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1 , 7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group , Tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group and heptadecane-1,17-diyl group Alkanediyl group;
Ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane- Branched alkanediyl groups such as 1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group;
Monocyclic 2 which is a cycloalkanediyl group such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclooctane-1,5-diyl group Valent alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbon such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane-2,6-diyl group, etc. Groups and the like.

Examples of the group in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ^b1 is replaced by —O— or —CO— include any of the formulas (b1-1) to (b1-3) The group represented by is mentioned. In the formulas (b1-1) to (b1-3) and the specific examples (b1-4) to (b1-11), * represents a bond with W ¹ .
In formula (b1-1),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, —CH ₂ — contained in the hydrocarbon group may be replaced with —O— or —CO—.
However, the total number of carbon atoms of L ^b2 and L ^b3 is 22 or less.
In formula (b1-2),
L ^b4 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, —CH ₂ — contained in the hydrocarbon group may be replaced with —O— or —CO—.
However, the total carbon number of L ^b4 and L ^b5 is 22 or less.
In formula (b1-3),
L ^b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
L ^b7 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, —CH ₂ — contained in the hydrocarbon group may be replaced with —O— or —CO—.
However, the total carbon number of L ^b6 and L ^b7 is 23 or less.

In formulas (b1-1) to (b1-3), when —CH ₂ — contained in the saturated hydrocarbon group is replaced with —O— or —CO—, the number of carbons before the replacement is The carbon number of the saturated hydrocarbon group.
Examples of the divalent saturated hydrocarbon group include the same divalent saturated hydrocarbon groups as those represented by L ^b1 .

L ^b2 is preferably a single bond.
L ^b3 is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.
L ^b4 is preferably a C 1-8 divalent saturated hydrocarbon group, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b6 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b7 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group In the saturated hydrocarbon group, —CH ₂ — may be replaced by —O— or —CO—.
Among these, a group represented by the formula (b1-1) or the formula (b1-3) is preferable.

Examples of formula (b1-1) include groups represented by formula (b1-4) to formula (b1-8).
In formula (b1-4),
L ^b8 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
In formula (b1-5),
L ^b9 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms.
L ^b10 represents a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total carbon number of L ^b9 and L ^b10 is 20 or less.
In formula (b1-6),
L ^b11 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b12 represents a single bond or a ^C 1-20 divalent saturated hydrocarbon group, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total carbon number of L ^b11 and L ^b12 is 21 or less.
In formula (b1-7),
L ^b13 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.
L ^b14 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b15 represents a single bond or a C 1-18 divalent saturated hydrocarbon group, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total carbon number of L ^b13 , L ^b14 and L ^b15 is 19 or less.
In formula (b1-8),
L ^b16 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b17 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b18 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total carbon number of L ^b16 , L ^b17 and L ^b18 is 19 or less.

L ^b8 is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.
L ^b9 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b10 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b11 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b12 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b13 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b14 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b15 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b16 preferably represents a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b17 preferably represents a ^C 1-6 divalent saturated hydrocarbon group.
L ^b18 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.

Examples of formula (b1-3) include groups represented by formula (b1-9) to formula (b1-11), respectively.
In formula (b1-9),
L ^b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b20 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. Also good. —CH ₂ — contained in the alkylcarbonyloxy group may be replaced with —O— or —CO—, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxy group.
However, the total carbon number of L ^b19 and L ^b20 is 23 or less.
In formula (b1-10),
L ^b21 represents a single bond or a divalent saturated hydrocarbon group having 1 to ²¹ carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b22 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b23 represents a single bond or a divalent saturated hydrocarbon group having 1 to ²¹ carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. Also good. —CH ₂ — contained in the alkylcarbonyloxy group may be replaced with —O— or —CO—, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxy group.
However, the total carbon number of L ^b21 , L ^b22 and L ^b23 is 21 or less.
In formula (b1-11),
L ^b24 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b25 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b26 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an alkylcarbonyloxy group. Also good. —CH ₂ — contained in the alkylcarbonyloxy group may be replaced with —O— or —CO—, and a hydrogen atom contained in the alkylcarbonyloxy group may be substituted with a hydroxy group.
However, L ^b24, the total number of carbon atoms of L ^b25 and L ^b26 is 21 or less.

  In formulas (b1-9) to (b1-11), when a hydrogen atom contained in a saturated hydrocarbon group is substituted with an alkylcarbonyloxy group, the number of carbon atoms before the substitution is changed to the saturated hydrocarbon group. The number of carbons.

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

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

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

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

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

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

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

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

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

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

As L ^b1 , * ¹ —CO—O— (CH ₂ ) _t — (t represents an integer of 0 to 6. * ¹ represents a bond to —C (Q ¹ ) (Q ² ) —. Represents a hand).

Examples of the anion represented by the formula (aa2) include the anions described below.

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

In formula (b2-1) to formula (b2-4),
R ^{b4 to} R ^b6 each independently represents an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms, The hydrogen atom contained in the aliphatic hydrocarbon group is a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. The hydrogen atom contained in the alicyclic hydrocarbon group which may be substituted is a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms or a glycidyloxy group. The hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group, or an alkoxy group having 1 to 12 carbon atoms.
R ^b4 and R ^b5 may combine with each other to form a ring together with the sulfur atom to which they are bonded, and —CH ₂ — contained in the ring is —O—, —S— or -CO- may be substituted.
R ^b7 and R ^b8 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represents an integer of 0 to 5.
When m2 is 2 or more, the plurality of R ^b7 may be the same or different, and when n2 is 2 or more, the plurality of R ^b8 may be the same or different.
R ^b9 and R ^b10 each independently represent an aliphatic hydrocarbon group having 1 to 36 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms.
R ^b9 and R ^b10 may be bonded together to form a ring together with the sulfur atom to which they are bonded, and —CH ₂ — contained in the ring is —O—, —S— or -CO- may be substituted.
R ^b11 represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^b12 represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and is included in the aliphatic hydrocarbon The hydrogen atom may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group is an alkoxy group having 1 to 12 carbon atoms or 1 to 1 carbon atoms. It may be substituted with 12 alkylcarbonyloxy groups.
R ^b11 and R ^b12 may be bonded to each other to form a ring including —CH—CO— to which they are bonded, and —CH ₂ — contained in the ring is —O—, —S -Or -CO- may be substituted.
R ^{b13 to} R ^b18 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
L ^b31 represents a sulfur atom or an oxygen atom.
o2, p2, s2, and t2 each independently represents an integer of 0 to 5.
q2 and r2 each independently represents an integer of 0 to 4.
u2 represents 0 or 1.
When o2 is 2 or more, multiple R ^b13 are the same or different, when p2 is 2 or more, multiple R ^b14 are the same or different, and when q2 is 2 or more, multiple R ^b15 are the same or different , When r2 is 2 or more, a plurality of R ^b16 are the same or different, when s2 is 2 or more, a plurality of R ^b17 are the same or different, and when t2 is 2 or more, a plurality of R ^b18 are the same or different Different.

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

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

As aromatic hydrocarbon group, phenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, p-ethylphenyl group, p-tert-butylphenyl group, p-cyclohexylphenyl group, p-adamantylphenyl group , Aryl groups such as a biphenylyl group, a naphthyl group, a phenanthryl group, a 2,6-diethylphenyl group, and a 2-methyl-6-ethylphenyl group.
When the aromatic hydrocarbon group includes an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, the aliphatic hydrocarbon group having 1 to 18 carbon atoms and the alicyclic hydrocarbon having 3 to 18 carbon atoms Groups are preferred.
Examples of the aromatic hydrocarbon group in which a hydrogen atom is substituted with an alkoxy group include a p-methoxyphenyl group.
Examples of the aliphatic hydrocarbon group in which a hydrogen atom is substituted with an aromatic hydrocarbon group include aralkyl groups such as a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group, and a naphthylethyl group.

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

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

The ring formed by combining R ^b9 and R ^b10 may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. This ring includes a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring. Examples thereof include a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring.
The ring formed by ^combining R ^b11 and R ^b12 may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. This ring includes a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring. Examples thereof include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

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

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

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

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

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

The salt (aa) is preferably a combination of the anions and cations described above. These anions and cations can be arbitrarily combined.
Examples of the salt (aa) include the salts described in Table 1.
For example, the salt (aa-1) in Table 1 represents the following salt in which the anion is (aa-1-1) and the cation is (b2-c-1).

  Especially, as salt (aa), salt (aa-1), salt (aa-2), salt (aa-5), salt (aa-6), salt (aa-11), salt (aa-12) ), Salt (aa-23), salt (aa-24), salt (aa-27), salt (aa-28), salt (aa-33), salt (aa-34), salt (aa-45) , Salt (aa-46), salt (aa-49), salt (aa-50), salt (aa-55), salt (aa-56), salt (aa-67), salt (aa-68), Salt (aa-71), salt (aa-72), salt (aa-77), salt (aa-78) and salt (aa-89) to salt (aa-106) are preferred.

<Method for producing salt (aa)>
A method for producing a salt (aa) (a salt represented by the formula (I)) composed of an anion represented by the formula (aa2) and an organic cation (Z ⁺ ) will be described.
The salt represented by the formula (I) includes a salt represented by the formula (Ia), a compound represented by the formula (I-b1), and a compound represented by the formula (I-b2). It can be produced by reacting in an acid catalyst in a solvent.
(Wherein, X ^a , X ^b , L ¹ , L ² , R ¹ , R ² , Q ¹ , Q ² , L ^b1 and ring W ¹ have the same meaning as described above.)
Examples of the acid catalyst in this reaction include sulfuric acid and p-toluenesulfonic acid.
Examples of the solvent in this reaction include chloroform, acetonitrile, dimethylformamide and the like.
The salt represented by the formula (Ia) can be synthesized by the methods described in JP2007-224008A and JP2012-224611A, and examples thereof include salts represented below. .
Examples of the compound represented by the formula (I-b1) and the formula (I-b2) include compounds represented by the following formulas, and can be easily obtained from the market.

[Acid generator]
The salt (aa) of the present invention can act as an acid generator in the resist composition. When the salt (aa) is used as an acid generator in the resist composition, it may contain two or more types of salts (aa) and, as will be described later, acids known in the resist field other than the salt (aa). You may further contain a generator.

[Resist composition]
The resist composition contains an acid generator containing the salt (aa) of the present invention and a resin having an acid labile group (hereinafter sometimes referred to as “resin (A)”). The term “acid labile group” as used herein 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 upon contact with an acid. .
The resist composition of the present invention may contain an acid generator known in the resist field (hereinafter sometimes referred to as “acid generator (B)”) as an acid generator other than the salt (aa).
The resist composition preferably contains a quencher (hereinafter sometimes referred to as “quencher (C)”) and / or a solvent (hereinafter sometimes referred to as “solvent (E)”).

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

<Structural unit (a1)>
The structural unit (a1) is derived from a monomer having an acid labile group (hereinafter sometimes referred to as “monomer (a1)”).
The acid labile group contained in the resin (A) is a group represented by formula (1) (hereinafter also referred to as group (1)) and / or a group represented by formula (2) (hereinafter referred to as group (2). )) Is preferred.
[In the formula (1), R ^{a1 to} R ^a3 each independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a combination of these, or R ^a1 and R ^a2 are bonded to each other to form a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.
ma and na each independently represents 0 or 1, and at least one of ma and na represents 1.
* Represents a bond. ]

[In Formula (2), R ^{a1 ′} and R ^{a2 ′} each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^{a3 ′} represents a hydrocarbon group having 1 to 20 carbon atoms. R ^{a2 ′} and R ^{a3 ′} are bonded to each other to form a divalent heterocyclic group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded and X, and the hydrocarbon group and the divalent —CH ₂ — contained in the ring group may be replaced by —O— or —S—.
X represents an oxygen atom or a sulfur atom.
na ′ represents 0 or 1.
* Represents a bond. ]
In addition, when —CH ₂ — contained in the hydrocarbon group and the divalent heterocyclic group is replaced with —O— or the like, the number of carbons before the replacement is the total number of carbons of these groups.

^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 of R ^{a1 to} R ^a3 may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following group (* represents a bond). Carbon number of the alicyclic hydrocarbon group of R ^{a1 to} R ^a3 is preferably 3 to 16.
Examples of the group combining an alkyl group and an alicyclic hydrocarbon group include, for example, methylcyclohexyl group, dimethylcyclohexyl group, methylnorbornyl group, cyclohexylmethyl group, adamantylmethyl group, adamantyldimethyl group, norbornyl An ethyl group etc. are mentioned.
Preferably, ma is 0 and na is 1.
Examples of —C (R ^a1 ) (R ^a2 ) (R ^a3 ) in the case where R ^a1 and R ^a2 are bonded to each other to form a divalent alicyclic hydrocarbon group include the following groups. The divalent alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms. * Represents a bond with -O-.

Examples of the hydrocarbon group of R ^{a1 ′ to} R ^{a3 ′} include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these.
Examples of the alkyl group and alicyclic hydrocarbon group are the same as those described above.
The aromatic hydrocarbon group includes phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl. Group, phenanthryl group, 2,6-diethylphenyl group, aryl group such as 2-methyl-6-ethylphenyl group, and the like.
Examples of the combined group include a group obtained by combining the above-described alkyl group and an alicyclic hydrocarbon group, an aralkyl group such as a benzyl group, and an aryl-cyclohexyl group such as a phenylcyclohexyl group.
^{Examples of the} divalent heterocyclic group formed together with the carbon atom and X to which R ^{a2 ′} and R ^{a3 ′} are bonded to each other and X include the following groups. * Represents a bond.
At least one of R ^{a1 ′} and R ^{a2 ′} is preferably a hydrogen atom.
na ′ is preferably 0.

As the group (1), a 1,1-dialkylalkoxycarbonyl group (in the formula (1), R ^{a1 to} R ^a3 are alkyl groups, ma = 0, na = 1), preferably tert-butoxy Carbonyl group), 2-alkyladamantan-2-yloxycarbonyl group (in formula (1), R ^a1 , R ^a2 , together with the carbon atom to which they are bonded form an adamantyl group, and R ^a3 is alkyl And ma = 0, na = 1) and 1- (adamantan-1-yl) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are each independently And R ^a3 is an adamantyl group, ma = 0, and na = 1). Specific examples include the following groups. * Represents a bond.

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

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

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

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

R ^a01 , R ^a4 and R ^a5 are preferably methyl groups.
L ^a01 , L ^a1 and L ^a2 are preferably an oxygen atom or * —O— (CH ₂ ) _k01 —CO—O— (where k01 is preferably an integer of 1 to 4, more preferably Is 1.), more preferably an oxygen atom.
R ^a02 , R ^a03 , R ^a04 , R ^a6, R ^a7 , the alkyl group, the alicyclic hydrocarbon group, and the combination thereof are the same as those ^exemplified for R ^{a1 to} R ^a3 in formula (1). Groups.
The carbon number of the alkyl group of R ^a02 , R ^a03 and R ^a04 is preferably 1 to 6, more preferably a methyl group or an ethyl group, and still more preferably a methyl group.
The carbon number of the alicyclic hydrocarbon group of R ^a02 , R ^a03 and R ^a04 is preferably 3-8, more preferably 3-6.
The group in which the alkyl group and the alicyclic hydrocarbon group are combined preferably has 18 or less total carbon atoms in combination of the alkyl group and the alicyclic hydrocarbon group.
R ^a02 and R ^a03 are preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group.
R ^a04 is preferably an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 5 to 12 carbon atoms, and more preferably a methyl group, an ethyl group, a cyclohexyl group, or an adamantyl group.
The carbon number of the alkyl group in R ^a6 and R ^a7 is preferably 1 to 6, more preferably a methyl group, an ethyl group, or an isopropyl group, and still more preferably an ethyl group or an isopropyl group.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 ′ is preferably 0 or 1.

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

As a structural unit (a1-1), the structural unit derived from the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Among them, a structural unit represented by any one of formulas (a1-1-1) to (a1-1-4) and a structural unit in which a methyl group corresponding to R ^a4 is replaced with a hydrogen atom are preferable. -1-1)-the structural unit represented by any one of formula (a1-1-4) is more preferable.

As the structural unit (a1-2), the structural unit represented by any one of the formulas (a1-2-1) to (a1-2-6) and the methyl group corresponding to R ^a5 were replaced with hydrogen atoms. Examples of the structural unit include formula (a1-2-2), formula (a1-2-5), and formula (a1-2-6).

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

Examples of the structural unit having the group (2) in the structural unit (a1) include a structural unit represented by the formula (a1-4) (hereinafter sometimes referred to as “structural unit (a1-4)”). .
[In the formula (a1-4),
R ^a32 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a33 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl An oxy group or a methacryloyloxy group is represented.
la represents an integer of 0 to 4. When la is 2 or more, the plurality of R ^a33 may be the same as or different from each other.
R ^a34 and R ^a35 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^a36 may represent a hydrocarbon group having 1 to 20 carbon atoms, R ^a35 and R ^a36 are bonded to each other Together with —C—O— to which they are bonded to form a divalent hydrocarbon group having 2 to 20 carbon atoms, and —CH ₂ — contained in the hydrocarbon group and the divalent hydrocarbon group is — O- or -S- may be substituted. ]

^Examples of the alkyl group for R ^a32 and R ^a33 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, and a hexyl group. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and further preferably a methyl group.
Examples of the halogen atom for R ^a32 and R ^a33 include a fluorine atom, a chlorine atom, and a bromine atom.
Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom include trifluoromethyl group, difluoromethyl group, methyl group, perfluoroethyl group, 1,1,1-trifluoroethyl group, 1,1,1. 2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 1,1,1,2,2-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3 4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 1,1,1,2,2,3,3,4,4-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group, etc. Can be mentioned.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, and a hexyloxy group. Especially, a C1-C4 alkoxy group is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is further more preferable.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group, and a butyryloxy group.
Examples of the hydrocarbon group R ^a34, R ^a35 and R ^a36, an alkyl group, an alicyclic hydrocarbon group include aromatic hydrocarbon groups, the same groups as R ^{a1 'and} R ^a2' of formula (2) Is mentioned. In particular, as R ^a36 , an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group formed by combining these Is mentioned.

In formula (a1-4), R ^a32 is preferably a hydrogen atom.
R ^a33 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group or an ethoxy group, and further preferably a methoxy group.
As la, 0 or 1 is preferable, and 0 is more preferable.
R ^a34 is preferably a hydrogen atom.
R ^a35 is preferably an alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group, more preferably a methyl group or an ethyl group.
The hydrocarbon group for R ^a36 is preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof. It is a group to be formed, more preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic aliphatic hydrocarbon group having 3 to 18 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms. The alkyl group and the alicyclic hydrocarbon group in R ^a36 are preferably unsubstituted. The aromatic hydrocarbon group for R ^a36 is preferably an aromatic ring having an aryloxy group having 6 to 10 carbon atoms.

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

  When resin (A) has a structural unit (a1-4), it is preferable that the content rate is 10-95 mol% with respect to the sum total of all the structural units of resin (A), 15-90 More preferably, it is mol%, and further preferably 20-85 mol%.

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

Examples of the halogen atom include a fluorine atom and a chlorine atom, and a fluorine atom is preferable.
Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a fluoromethyl group and a trifluoromethyl group. Groups.
In formula (a1-5), R ^a8 is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.
L ⁵¹ is preferably an oxygen atom.
Of L ⁵² and L ⁵³ , one is preferably —O— and the other is preferably —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—.

As a structural unit (a1-5), the structural unit derived from the monomer described in Unexamined-Japanese-Patent No. 2010-611117 is mentioned, for example. Among these, structural units each represented by formula (a1-5-1) to formula (a1-5-4) are preferable, and are represented by formula (a1-5-1) or formula (a1-5-2). A structural unit is more preferable.

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

In addition, examples of the structural unit (a1) include the following structural units.

  When resin (A) contains the said structural unit, the content rate is 10-95 mol% with respect to all the structural units of resin (A), 15-90 mol% is more preferable, 20-85 mol % Is more preferable.

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

<Structural unit (a2)>
The hydroxy group contained in the structural unit (a2) may be an alcoholic hydroxy group or a phenolic hydroxy group.
When a resist pattern is produced from the resist composition of the present invention, when a high energy beam such as a KrF excimer laser (248 nm), an electron beam or EUV (ultra-ultraviolet light) is used as an exposure light source, the structural unit (a2) It is preferable to use the structural unit (a2) having a phenolic hydroxy group. When an ArF excimer laser (193 nm) or the like is used, the structural unit (a2) having an alcoholic hydroxy group is preferable as the structural unit (a2), and the structural unit (a2-1) is more preferable. As a structural unit (a2), 1 type may be included independently and 2 or more types may be included.

Examples of the structural unit having a phenolic hydroxy group in the structural unit (a2) include a structural unit represented by the formula (a2-A) (hereinafter sometimes referred to as “structural unit (a2-A)”).
[In the formula (a2-A),
R ^a50 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a51 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl An oxy group or a methacryloyloxy group is represented.
A ^a50 represents a single bond or ^* —X ^a51 — (A ^a52 —X ^a52 ) _na —, and * represents a bond to the carbon atom to which —R ^a50 is bonded.
A ^a52 each independently represents an alkanediyl group having 1 to 6 carbon atoms.
X ^a51 and X ^a52 each independently represent —O—, ^—CO —O— or —O—CO—.
na represents 0 or 1.
mb represents an integer of 0 to 4. When mb is an integer greater than or equal to 2, several ^Ra51 may mutually be same or different. ]

^Examples of the halogen atom for R ^a50 include a fluorine atom, a chlorine atom and a bromine atom.
^Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom in R ^a50 include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 1,1,1-trifluoroethyl group, 1,1,2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 1,1,1,2,2-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2, 3,3,4,4-octafluorobutyl group, butyl group, perfluoropentyl group, 1,1,1,2,2,3,3,4,4-nonafluoropentyl group, pentyl group, hexyl group and perfluoro A hexyl group is mentioned.
R ^a50 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and even more preferably a hydrogen atom or a methyl group.
^Examples of the alkyl group for R ^a51 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group.
^Examples of the R ^a51 alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, and a tert-butoxy group. A C1-C4 alkoxy group is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is more preferable.
^Examples of the alkylcarbonyl group for R ^a51 include an acetyl group, a propionyl group, and a butyryl group.
^Examples of the alkylcarbonyloxy group for R ^a51 include an acetyloxy group, a propionyloxy group, and a butyryloxy group.
R ^a51 is preferably a methyl group.

^* —X ^a51 — (A ^a52 —X ^a52 ) _na — includes ^* —O—, ^* —CO—O—, ^* —O—CO—, ^* —CO—O—A ^a52 —CO—O—, ^* —O—CO—A ^a52 —O—, ^* —O—A ^a52 —CO—O—, ^* —CO—O—A ^a52 —O—CO—, ^* —O—CO—A ^a52 —O—CO -. Of these, ^* —CO—O—, ^* —CO—O—A ^a52 —CO—O— or ^* —O—A ^a52 —CO—O— is preferable.

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

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

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

As the structural unit (a2-A), structural units represented by the formulas (a2-2-1) to (a2-2-4) and a structural unit in which a methyl group corresponding to R ^a50 is replaced with a hydrogen atom are included. Can be mentioned. The structural unit (a2-A) includes a structural unit represented by the formula (a2-2-1), a structural unit represented by the formula (a2-2-3), and a methyl group corresponding to R ^a50 in a hydrogen atom. A substituted structural unit is preferred.

  Examples of the structural unit (a2-A) include structural units derived from monomers described in JP2010-204634A and JP2012-12577A.

  When the structural unit (a2-A) is contained in the resin (A), the content of the structural unit (a2-A) is preferably 5 to 80 mol%, more preferably based on all structural units. It is 10-70 mol%, More preferably, it is 15-65 mol%.

Examples of the structural unit having an alcoholic hydroxy group in the structural unit (a2) include a structural unit represented by the formula (a2-1) (hereinafter sometimes referred to as “structural unit (a2-1)”).
In formula (a2-1),
L ^a3 represents —O— or ^* —O— (CH ₂ ) _k2 —CO—O—,
k2 represents any integer of 1 to 7. * Represents a bond with -CO-.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 each independently represent a hydrogen atom, a methyl group or a hydroxy group.
o1 represents an integer of 0 to 10.

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

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

  When resin (A) contains a structural unit (a2-1), the content rate is 1-45 mol% normally with respect to all the structural units of resin (A), Preferably it is 1-40 mol%. Yes, more preferably 1 to 35 mol%, still more preferably 2 to 20 mol%, and even more preferably 2 to 10 mol%.

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

The structural unit (a3) is preferably a structural unit represented by the formula (a3-1), the formula (a3-2), the formula (a3-3), or the formula (a3-4). These 1 type may be contained independently and 2 or more types may be contained.
[In Formula (a3-1), Formula (a3-2), Formula (a3-3) and Formula (a3-4),
L ^a4 , L ^a5 and L ^a6 are each independently represented by —O— or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents any integer of 1 to 7). Represents a group.
L ^a7 is —O—, ^* —O—L ^a8 —O—, ^* —O—L ^a8 —CO—O—, ^* —O—L ^a8 —CO—O—L ^a9 —CO—O— or ^* —O—L ^a8 —O—CO—L ^a9 —O— is represented.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
* Represents a bond with a carbonyl group.
R ^a18 , R ^a19 and R ^a20 each independently represent a hydrogen atom or a methyl group.
R ^a24 represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
R ^a22 , R ^a23 and R ^a25 each independently represent a carboxy group, a cyano group or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents any integer of 0 to 5.
q1 represents any integer of 0 to 3.
r1 represents any integer of 0 to 3.
w1 represents an integer of 0 to 8.
When p1, q1, r1, and / or w1 is 2 or more, a plurality of R ^a21 , R ^a22 , R ^a23 and / or R ^a25 may be the same as or different from each other. ]

Examples of the aliphatic hydrocarbon group for R ^a21 , R ^a22 , R ^a23 and R ^a25 include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group and tert-butyl group. It is done.
Examples of the halogen atom for R ^a24 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
^Examples of the alkyl group for ^Ra24 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group, and preferably have 1 to 4 carbon atoms. And more preferably a methyl group or an ethyl group.
Examples of the alkyl group having a halogen atom of Ra ²⁴ include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group, perfluoro A hexyl group, a trichloromethyl group, a tribromomethyl group, a triiodomethyl group, etc. are mentioned.

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

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

In formula (a3-4), R ^a24 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and still more preferably a hydrogen atom or a methyl group. It is.
R ^a25 is preferably a carboxy group, a cyano group, or a methyl group.
L ^a7 is preferably —O— or ^* —O—L ^a8 —CO—O—, more preferably —O—, —O—CH ₂ —CO—O— or —O—C ₂ H ₄ —. CO-O-.
In particular, the formula (a3-4) is preferably the formula (a3-4) ′.
(Wherein R ^a24 and L ^a7 represent the same meaning as described above.)

As the structural unit (a3), a monomer derived from JP2010-204646, a monomer described in JP2000-122294A, a structure derived from a monomer described in JP2012-41274A Units are listed. As the structural unit (a3), formula (a3-1-1) to formula (a3-1-2), formula (a3-2-1) to formula (a3-2-2), formula (a3-3) 1) to a structural unit represented by any one of formulas (a3-3-2) and (a3-4-1) to (a3-4-12), and R ^a18 , R ^a19 , A structural unit in which a methyl group corresponding to R ^a20 and R ^a24 is replaced with a hydrogen atom is preferred.

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%.
Moreover, the content rate of a structural unit (a3-1), a structural unit (a3-2), a structural unit (a3-3), and a structural unit (a3-4) is respectively with respect to all the structural units of resin (A). 5 to 60 mol% is preferable, 5 to 50 mol% is more preferable, and 10 to 50 mol% is more preferable.

<Structural unit (a4)>
As the structural unit (a4), a structural unit represented by formula (a4-0) can be given.
[In the formula (a4-0),
R ⁵ represents a hydrogen atom or a methyl group.
L ⁴ represents a single bond or an aliphatic saturated hydrocarbon group having 1 to 4 carbon atoms.
L ³ represents a perfluoroalkyl cycloalkanediyl group perfluoro alkanediyl group or 3 to 12 carbon atoms having 1 to 8 carbon atoms.
R ⁶ represents a hydrogen atom or a fluorine atom. ]

As the aliphatic saturated hydrocarbon group for L ⁴ , a linear alkanediyl group such as methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, ethane-1,1- Branched alkanediyl such as diyl group, propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group Groups.

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

L ⁴ is preferably a single bond, a methylene group or an ethylene group, and more preferably a single bond or a methylene group.
L ³ is preferably a C 1-6 perfluoroalkanediyl group, more preferably a C 1-3 perfluoroalkanediyl group.

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

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

^Examples of the hydrocarbon group for R ^a42 include chain and cyclic saturated hydrocarbon groups, aromatic hydrocarbon groups, and groups formed by combining these.
Chain and cyclic saturated hydrocarbon groups are formed by combining linear or branched alkyl groups and monocyclic or polycyclic alicyclic hydrocarbon groups, and alkyl groups and alicyclic hydrocarbon groups. And saturated hydrocarbon groups.

Chain saturated hydrocarbon groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl. Groups. Examples of the cyclic saturated hydrocarbon group include a cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group; a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups (* represents a bond). And polycyclic alicyclic hydrocarbon groups such as
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.

R ^a42 may have a halogen atom and a group represented by the formula (a-g3) as a substituent. 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.
[In the formula (a-g3),
X ^a43 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ^a45 represents a saturated hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
* Represents a bond. ]
However, in R ^a42 —X ^a43 —A ^a45 , when R ^a42 does not have a halogen atom, A ^a45 represents a C ^1-17 aliphatic hydrocarbon group having at least one halogen atom.

^As the saturated hydrocarbon group for A ^a45, the same groups as those exemplified for R ^a42 can be mentioned.
R ^a42 is preferably a saturated hydrocarbon group which may have a halogen atom, more preferably an alkyl group having a halogen atom and / or a saturated hydrocarbon group having a group represented by the formula (a-g3).
When R ^a42 is a saturated hydrocarbon group having a halogen atom, it is preferably a saturated hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, still more preferably 1 to 1 carbon atoms. 6 perfluoroalkyl group, particularly preferably a C 1-3 perfluoroalkyl group. Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, and a perfluorooctyl group. Examples of the perfluorocycloalkyl group include a perfluorocyclohexyl group.
When R ^a42 is a saturated hydrocarbon group having a group represented by the formula (a-g3), including the number of carbons contained in the group represented by the formula (a-g3), The total carbon number is preferably 15 or less, and more preferably 12 or less. When it has a group represented by the formula (a-g3) as a substituent, the number is preferably 1.

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

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

A more preferred structure of the partial structure represented by * -A ^a46 -X ^a44 -A ^a47 (* is a bond to a carbonyl group) is the following structure.
In addition, when —CH ₂ — contained in the hydrocarbon group represented by R ^a42 is replaced by —O— or the like, the number of carbons before the replacement is ^{defined as} the total number of carbon atoms of the hydrocarbon group.

^As the alkanediyl group of ^Aa41 , a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group Linear alkanediyl group such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,2-diyl group, 1-methylbutane-1,4-diyl group, Examples include branched alkanediyl groups such as 2-methylbutane-1,4-diyl group.
^Examples of the substituent in the alkanediyl group of A ^a41 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
A ^a41 is preferably an alkanediyl group having 1 to 4 carbon atoms, more preferably an alkanediyl group having 2 to 4 carbon atoms, and still more preferably an ethylene group.

The saturated hydrocarbon group of A ^a42 , A ^a43 and A ^{a44 in} the group represented by the formula (a-g1) is preferably a chain or cyclic saturated hydrocarbon group or a group formed by combining them. . Examples of the saturated hydrocarbon group include a linear or branched alkyl group and a monocyclic alicyclic hydrocarbon group, and a saturated hydrocarbon group formed by combining an alkyl group and an alicyclic hydrocarbon group. Is mentioned. Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, 1-methylpropane-1,3-diyl group, Examples include 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.
^Examples of the substituent for the saturated hydrocarbon group of A ^a42 , A ^a43 and A ^a44 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
s is preferably 0.

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

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

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. ]

The hydrocarbon group for R ^f22 includes aliphatic hydrocarbon groups formed by chain, cyclic, and combinations thereof. As the aliphatic hydrocarbon group, an alkyl group and an alicyclic hydrocarbon group are preferable.
Examples of the hydrocarbon group having a fluorine atom 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.
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 structural unit represented by formula (a4-4) include structural units in which the methyl group corresponding to R ^f21 is replaced with a hydrogen atom in the following structural units and structural units represented by the following formulas. It is done.

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

<Structural unit (a5)>
Examples of the non-elimination hydrocarbon group that the structural unit (a5) has include a group having a linear, branched, or cyclic hydrocarbon group. Among these, the structural unit (a5) preferably includes an alicyclic hydrocarbon group.
As a structural unit (a5), the structural unit represented by a formula (a5-1) is mentioned, for example.
[In the formula (a5-1),
R ⁵¹ represents a hydrogen atom or a methyl group.
R ⁵² represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms. . However, the hydrogen atom bonded to the carbon atom at the coupling position with the L ⁵⁵ is not substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms.
L ⁵⁵ represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced by —O— or —CO—. . ]

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

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

In the structural unit represented by the formula (a5-1), examples of the group in which —CH ₂ — contained in the saturated hydrocarbon group is replaced by —O— or —CO— include, for example, the formula (L1-1) to And a group represented by the formula (L1-4). In the following formula, * represents a bond with an oxygen atom.
In formula (L1-1),
X ^x1 represents * —O—CO— or * —CO—O— (* represents a bond to A ^f13 ) L ^x1 represents a divalent aliphatic saturated hydrocarbon having 1 to 16 carbon atoms Represents a group.
L ^x2 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
However, the total carbon number of L ^x1 and L ^x2 is 16 or less.
In formula (L1-2),
L ^x3 represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms.
L ^x4 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
However, the total carbon number of L ^x3 and L ^x4 is 17 or less.
In formula (L1-3),
L ^x5 represents a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^x6 and L ^x7 each independently represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms.
However, the total carbon number of L ^x5 , L ^x6 and L ^x7 is 15 or less.
In formula (L1-4),
L ^x8 and L ^x9 represent a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms.
W ^x1 represents a divalent alicyclic saturated hydrocarbon group having 3 to 15 carbon atoms.
However, the total carbon number of L ^x8 , L ^x9 and W ^x1 is 15 or less.

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

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

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

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

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

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

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

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

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

Each structural unit constituting the resin (A) may be used alone or in combination of two or more, and is produced by a known polymerization method (for example, radical polymerization method) using a monomer that derives these structural units. be able to. The content rate of each structural unit which resin (A) has can be adjusted with the usage-amount of the monomer used for superposition | polymerization.
The weight average molecular weight of the resin (A) is preferably 2,000 or more (more preferably 2,500 or more, more preferably 3,000 or more), 50,000 or less (more preferably 30,000 or less, further preferably 15,000 or less). In the present specification, the weight average molecular weight is a value obtained by gel permeation chromatography under the conditions described in Examples.

<Resin other than resin (A)>
The resist composition of the present invention may contain a resin other than the resin (A).
As the resin other than the resin (A), a resin containing the structural unit (a4) (however, the structural unit (a1) is not included. Hereinafter, it may be referred to as “resin (X)”) is preferable. In the resin (X), the content of the structural unit (a4) is preferably 40 mol% or more, more preferably 45 mol% or more, and still more preferably 50 mol% or more with respect to all the structural units of the resin (X). .
Examples of the structural unit that the resin (X) may further include a structural unit derived from the structural unit (a2), the structural unit (a3), the structural unit (a5), and other known monomers.
The weight average molecular weight of the resin (X) is preferably 8,000 or more (more preferably 10,000 or more) and 80,000 or less (more preferably 60,000 or less). The means for measuring the weight average molecular weight of the resin (X) is the same as that for the resin (A).
When the resist composition contains the resin (X), the content thereof is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass with respect to 100 parts by mass of the resin (A). Preferably it is 1-40 mass parts, Most preferably, it is 2-30 mass parts.

  As for the total content rate of resin other than resin (A) and resin (A), 80 to 99 mass% is preferable with respect to solid content of a resist composition. The solid content of the resist composition and the resin content relative thereto can be measured by a known analysis means such as liquid chromatography or gas chromatography.

<Acid generator (B)>
The resist composition of the present invention contains salt (aa) as an acid generator.
As described above, the acid generator contained in the resist composition may further contain an acid generator (B) known in the resist field other than the salt (a). The acid generator (B) may be an ionic acid generator or a nonionic generator. Preferably, it is an ionic acid generator. Examples of the ionic acid generator include an ionic acid generator composed of a combination of a known cation and a known anion.

  Examples of the acid generator (B) include organic sulfonium salts of organic sulfonic acids, and acid generators described in JP2013-68914A, JP2013-3155A, JP2013-11905A, and the like. Can be mentioned. Specifically, a salt represented by any one of formulas (B1-1) to (B1-48) can be given. Among them, those containing an arylsulfonium cation are preferable. Formula (B1-1) to Formula (B1-3), Formula (B1-5) to Formula (B1-7), Formula (B1-11) to Formula (B1-14) ), Formula (B1-17), Formula (B1-20) to Formula (B1-26), Formula (B1-29), Formula (B1-31) to Formula (B1-48). A salt is more preferred.

In the resist composition of the present invention, the content of the salt (aa) is preferably 0.1% by mass or more and 35% by mass or less, and 0.5% by mass or more and 30% by mass with respect to the solid content of the resist composition. The following is more preferable, and 1% by mass to 25% by mass is further preferable.
When the acid generator (B) is included, the total content of the salt (aa) and the acid generator (B) is preferably 1.5% by mass or more with respect to 100 parts by mass of the resin (A). (More preferably 3% by mass or more), preferably 40% by mass or less (more preferably 35% by mass or less).
In the resist composition of the present invention, the content ratio of the salt (aa) to the acid generator (B) (mass ratio; salt (aa): acid generator (B)) is usually 1: 99-100. : 0, preferably 1:99 to 99: 1, more preferably 2:98 to 98: 2, and even more preferably 5:95 to 95: 5.

  The content of the acid generator (B) is preferably 1 part by mass or more (more preferably 3 parts by mass or more), preferably 30 parts by mass or less (more preferably 25 parts by mass) with respect to 100 parts by mass of the resin (A). Part or less). The resist composition of the present invention may contain one kind of acid generator (B) alone, or may contain plural kinds.

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

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

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

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

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

The acidity in a salt that generates an acid having a weaker acidity than the acid generated from the salt (aa) and the acid generator (B) is represented by an acid dissociation constant (pKa). The salt that generates an acid having a lower acidity than the acid generated from the salt (aa) and the acid generator (B) is a salt in which the acid dissociation constant of the acid generated from the salt is usually −3 <pKa, A salt of −1 <pKa <7 is preferable, and a salt of 0 <pKa <5 is more preferable.
Examples of the salt that generates an acid having a lower acidity than the acid generated from the salt (aa) and the acid generator (B) include a salt represented by the following formula, and a formula (D) described in JP-A-2015-147926. (Hereinafter, also referred to as “weak acid inner salt (D)”), JP 2012-229206 A, JP 2012-6908 A, JP 2012-72109 A, Examples thereof include salts described in JP2011-39502A and JP2011-191745A. Preferably, it is a weak acid inner salt (D).

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

  The content of the quencher (C) is preferably 0.01 to 5% by mass and more preferably 0.01 to 3% by mass in the solid content of the resist composition.

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

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

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

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

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

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

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

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

When producing a positive resist pattern from the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer may be various alkaline aqueous solutions used in this field. Examples thereof include an aqueous solution of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline). The alkali developer may contain a surfactant.
It is preferable to wash the resist pattern with ultrapure water after development, and then remove the water remaining on the substrate and the pattern.

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

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

<Application>
The resist composition of the present invention is suitable as a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure, or a resist composition for EUV exposure. Yes, it is more suitable as a resist composition for ArF excimer laser exposure, and is useful for fine processing of semiconductors.

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

Example 1: Synthesis of a salt represented by the formula (aa-1)
10 parts of a salt represented by the formula (aa-1-a), 12.29 parts of a compound represented by the formula (aa-1-b), 70 parts of dimethylformamide and 1.67 parts of sulfuric acid are added, and 70 ° C. For 10 hours. The obtained mixture was cooled to 23 ° C., 190 parts of chloroform was added and stirred, and then filtered. The collected filtrate was charged with 290 parts of 5% sodium bicarbonate water, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. The recovered organic layer was charged with 60 parts of ion exchange water, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. After concentration of the obtained organic layer, 50 parts of acetonitrile and 200 parts of tert-butyl methyl ether were added to the concentration residue and stirred, and then the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 10.24 parts of the salt represented by the formula (aa-1).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (−) Spectrum): M ^- 665.3

Example 2: Synthesis of a salt represented by the formula (aa-2)
10 parts of a salt represented by the formula (aa-1-a), 8.74 parts of a compound represented by the formula (aa-2-b), 70 parts of dimethylformamide and 1.67 parts of sulfuric acid are added, and 70 ° C. For 10 hours. The obtained mixture was cooled to 23 ° C., 200 parts of chloroform was added and stirred, and then filtered. The collected filtrate was charged with 290 parts of 5% sodium bicarbonate water, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. The recovered organic layer was charged with 60 parts of ion exchange water, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. After concentration of the obtained organic layer, 20 parts of acetonitrile and 200 parts of tert-butyl methyl ether were added to the concentration residue and stirred, and then the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 7.88 parts of the salt represented by the formula (aa-2).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 561.3

Example 3: Synthesis of salt represented by formula (aa-11)
10.24 parts of a salt represented by the formula (aa-11-a), 12.29 parts of a compound represented by the formula (aa-1-b), 70 parts of dimethylformamide and 1.67 parts of sulfuric acid are added, Stir at 70 ° C. for 10 hours. The obtained mixture was cooled to 23 ° C., 200 parts of chloroform was added and stirred, and then filtered. The collected filtrate was charged with 290 parts of 5% sodium bicarbonate water, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. The recovered organic layer was charged with 60 parts of ion exchange water, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. After the obtained organic layer was concentrated, 40 parts of acetonitrile and 200 parts of tert-butyl methyl ether were added to the concentrated residue and stirred, and then the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 10.12 parts of the salt represented by the formula (aa-11).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 679.4

Example 4: Synthesis of salt represented by formula (aa-12)
10.24 parts of a salt represented by the formula (aa-11-a), 8.74 parts of a compound represented by the formula (aa-2-b), 70 parts of dimethylformamide and 1.67 parts of sulfuric acid are added, Stir at 70 ° C. for 10 hours. The obtained mixture was cooled to 23 ° C., 200 parts of chloroform was added and stirred, and then filtered. The collected filtrate was charged with 290 parts of 5% sodium bicarbonate water, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. The recovered organic layer was charged with 60 parts of ion exchange water, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. After concentration of the obtained organic layer, 20 parts of acetonitrile and 200 parts of tert-butyl methyl ether were added to the concentration residue and stirred, and then the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 9.28 parts of the salt represented by the formula (aa-12).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 575.3

Example 5: Synthesis of salt represented by formula (aa-89)
10 parts of a salt represented by the formula (aa-1-a), 9.85 parts of a compound represented by the formula (aa-89-b), 70 parts of dimethylformamide and 1.67 parts of sulfuric acid were added, and 70 ° C. For 10 hours. The obtained mixture was cooled to 23 ° C., 200 parts of chloroform was added and stirred, and then filtered. The collected filtrate was charged with 290 parts of 5% sodium bicarbonate water, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. The recovered organic layer was charged with 60 parts of ion exchange water, stirred at 23 ° C. for 30 minutes, and separated to recover the organic layer. This washing operation was performed 5 times. After concentration of the obtained organic layer, 20 parts of acetonitrile and 200 parts of tert-butyl methyl ether were added to the concentration residue and stirred, and then the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 2.48 parts of the salt represented by the formula (aa-89).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (-) Spectrum): M ^- 589.2

Example 6: Synthesis of salt represented by formula (aa-90)
1.59 parts of the compound represented by the formula (aa-89) and 10 parts of acetonitrile were mixed, stirred at 23 ° C. for 30 minutes, and then cooled to 5 ° C. To the obtained mixed solution, a mixed solution of 0.04 part of sodium borohydride and 0.53 part of ion-exchanged water was added and stirred at 23 ° C. for 18 hours. After concentrating the obtained reaction mixture, 30 parts of chloroform and 30 parts of ion-exchanged water were added to the concentration residue and stirred at 23 ° C. for 30 minutes, followed by liquid separation to take out the organic layer. 30 parts of ion-exchanged water was added to the obtained organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, followed by liquid separation to take out the organic layer. This washing operation was repeated 5 times. After concentration of the obtained organic layer, 10 parts of tert-butyl methyl ether was added to the concentration residue and stirred, and then the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 0.75 part of a salt represented by the formula (aa-90).

MS (ESI (+) Spectrum): M ⁺ 263.1
MS (ESI (−) Spectrum): M ^- 593.3

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

Synthesis Example 1: Synthesis of Resin A1 As the monomer, monomer (a1-1-3), monomer (a1-2-5), monomer (a2-1-3) and monomer (a3-4-2) were used. The molar ratio [monomer (a1-1-3): monomer (a1-2-9): monomer (a2-1-3): monomer (a3-4-2)] is 45: 14: 2.5: 38. The resulting mixture was mixed with propylene glycol monomethyl ether acetate having a mass ratio of 1.5 times the total monomer amount to obtain 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 73 ° 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 propylene glycol monomethyl ether acetate, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by reprecipitation operation of filtering the resin twice. Resin A1 having a molecular weight of 7.6 × 10 ³ was obtained in a yield of 68%. This resin A1 has the following structural units.

Synthesis Example 2: Synthesis of Resin X1 Monomer (a5-1-1) and monomer (a4-0-12) were used as monomers, and the molar ratio [monomer (a5-1-1): monomer (a4-0-) 12)] was 50:50, and methyl isobutyl ketone 1.2 mass times the total monomer amount was added to obtain a solution. To this solution, 3 mol% of azobis (2,4-dimethylvaleronitrile) as an initiator was added based on the total amount of monomers, and heated at 70 ° C. for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate a resin, and this resin was filtered to obtain a resin X1 having a weight average molecular weight of 1.0 × 10 ^{4 in} a yield of 91%. This resin X1 has the following structural units.

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

<Resin>
A1, X1: Resin A1, Resin X1
<Salt (aa)>
aa-1: salt represented by formula (aa-1) aa-2: salt represented by formula (aa-2) aa-11: salt represented by formula (aa-11) aa-12: formula Salt represented by (aa-12) aa-89: Salt represented by formula (aa-89) aa-90: Salt represented by formula (aa-90) <Acid generator>
B1-21: a salt represented by the formula (B1-21) (synthesized according to Examples in JP 2012-224611 A)
B1-22: a salt represented by the formula (B1-22) (synthesized according to Examples in JP 2012-224611 A)
IX-1: Synthesis according to the example of JP 2011-37837 A IX-2: Synthesis according to the example of JP 2011-246444 A
<Compound (D)>
D1: (Tokyo Chemical Industry Co., Ltd.)
<Solvent>
Propylene glycol monomethyl ether acetate 265 parts Propylene glycol monomethyl ether 20 parts 2-heptanone 20 parts γ-butyrolactone 3.5 parts

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

  In the resist pattern obtained after development, the exposure amount at which the hole diameter formed using the mask was 50 nm was defined as the effective sensitivity.

<Evaluation of CD uniformity (CDU)>
In terms of effective sensitivity, the hole diameter of a pattern formed with a mask having a hole diameter of 55 nm was measured 24 times per hole, and the average value was taken as the average hole diameter of one hole. A standard deviation is obtained using a population obtained by measuring 400 average hole diameters of a pattern formed with a mask having a hole diameter of 55 nm in the same wafer,
When the standard deviation is 1.70 nm or less,
The case where the standard deviation was larger than 1.70 nm was judged as “x”.
The results are shown in Table 3. Numerical values in parentheses indicate standard deviation (nm).

  Since the salt of the present invention and the resist composition containing the salt can obtain a resist pattern having good CD uniformity, it is suitable for fine processing of semiconductors and is extremely useful industrially.

Claims (10)

A salt having a group represented by the formula (aa1).
[In the formula (aa1),
X ^a and X ^b each independently represent an oxygen atom or a sulfur atom.
Ring W ¹ represents an alicyclic hydrocarbon group having 3 to 36 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group includes a hydroxy group, an alkyl group having 1 to 12 carbon atoms, and 1 to 1 carbon atoms. 12 alkoxy groups having 2 to 13 carbon atoms, alkylcarbonyl groups having 2 to 13 carbon atoms, alkylcarbonyloxy groups having 2 to 13 carbon atoms, alicyclic hydrocarbon groups having 3 to 12 carbon atoms, carbon It may be substituted with an aromatic hydrocarbon group of several 6 to 10 or a combination thereof.
L ¹ and L ² each independently represent a single bond or a hydrocarbon group having 1 to 12 carbon atoms, and —CH ₂ — contained in the hydrocarbon group is —O—, —S—, —CO—. Alternatively, it may be replaced by -S (O) _2- .
R ¹ and R ² each independently represents a C 3-18 alicyclic hydrocarbon group which may have a substituent, and —CH ₂ — contained in the alicyclic hydrocarbon group is: -O-, -S-, -CO- or -S (O) _2- may be substituted.
* Represents a bond. ]   The salt according to claim 1, comprising an anion having a group represented by the formula (aa1) and a cation.   The salt according to claim 2, wherein the anion having a group represented by the formula (aa1) is an anion having a group represented by the formula (aa1) and a sulfonate. The salt according to claim 3, wherein the anion having a group represented by the formula (aa1) and a sulfonate is a salt having an anion represented by the formula (aa2).
[In the formula (aa2),
X ^a , X ^b , L ¹ , L ² , R ¹ , R ² and ring W ¹ represent the same meaning as described above.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced by —O— or —CO—, and the saturated The hydrogen atom contained in the hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group. ] Ring ^{W 1} is represented by Formula ring represented by (W1-1), the ring represented by the formula (w1-2), ring or the formula represented by the formula (w1-3) (w1-6) The salt according to any one of claims 1 to 4, which is a ring.
[In formula (w1-1), formula (w1-2), formula (w1-3) and formula (w1-6),
The hydrogen atom contained in the ring is a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 13 carbon atoms, an alkylcarbonyl group having 2 to 13 carbon atoms, carbon The alkylcarbonyloxy group having 2 to 13 carbon atoms, the alicyclic hydrocarbon group having 3 to 12 carbon atoms, or the aromatic hydrocarbon group having 6 to 10 carbon atoms may be substituted. ] L ^b1 represents # —CO—O— (CH ₂ ) _t — (t represents an integer of 0 to 6. # represents a bond with —C (Q ¹ ) (Q ² ) —. The salt according to claim 4 or 5, wherein   The acid generator containing the salt in any one of Claims 1-6.   A resist composition comprising the acid generator according to claim 7 and a resin having an acid labile group.   Furthermore, the resist composition of Claim 8 containing the salt which generate | occur | produces the acid whose weakness is weaker than the acid generated from an acid generator. (1) The process of apply | coating the resist composition of Claim 8 or 9 on a board | substrate,
(2) A step of drying the composition after application to form 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: