JP2018090779A - Resin, resist composition, and method for producing resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist composition capable of producing a resist pattern with good line edge roughness.SOLUTION: A resin contains structural units represented by formula (I) and formula (a3-4). [Ar is a substituted or unsubstituted aromatic hydrocarbon group; Ris H or methyl; Ris H, an alkyl unsubstituted or substituted with a halogen, or the like; Rand Rare each independently a hydrocarbon; Ris carboxyl, cyano, or the like; Lis L-O, L-CO-O, or the like; and w1 is an integer of 0-8.]SELECTED DRAWING: None

Description

  The present invention relates to a resin, a resist composition, a method for producing a resist pattern using the resist composition, and the like.

Patent Document 1 describes a resist composition containing a resin composed of the following structural units.
Patent Document 2 describes a resist composition containing a resin composed of the following structural units.

JP 2010-122579 A JP 2014-74731 A

  A resist pattern formed from a resist composition containing the above resin may not always satisfy line edge roughness (LER).

The present invention includes the following inventions.
[1] A resin comprising a structural unit represented by formula (I) and a structural unit represented by formula (a3-4).
[In the formula (I),
R ¹ represents a hydrogen atom or a methyl group.
R ² and R ³ each independently represents a saturated hydrocarbon group having 1 to 6 carbon atoms.
Ar represents an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent. ]
[In the formula (a3-4),
R ^a24 represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
L ^a7 is a single bond, ^* —L ^a8 —O—, ^* —L ^a8 —CO—O—, ^* —L ^a8 —CO—O—L ^a9 —CO—O— or ^* —L ^a8 —O—CO ^-La9- O- is represented.
* Represents a bond with -O-.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
R ^a25 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
w1 represents an integer of 0 to 8. When w1 is 2 or more, the plurality of R ^a25 may be the same as or different from each other. ]
[2] The resin according to [1], wherein R ² and R ³ are each independently a methyl group or an ethyl group.
[3] The resin according to [1] or [2], wherein Ar is a phenyl group which may have a substituent.
[4] A resist composition comprising the resin according to any one of [1] to [3] and an acid generator.
[5] The resist composition according to [4], further comprising a salt that generates an acid having a lower acidity than an acid generated from the acid generator.
[6] (1) A step of applying the resist composition according to [4] or [5] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) A method for producing a resist pattern, comprising: a step of heating the composition layer after exposure; and (5) a step of developing the composition layer after heating.

  By using the resist composition using the resin of the present invention, a resist pattern can be produced with good line edge roughness (LER).

In the present specification, “(meth) acrylate” means “at least one of acrylate and methacrylate”. The notations such as “(meth) acrylic acid” and “(meth) acryloyl” have the same meaning.
In addition, unless otherwise specified, “aliphatic hydrocarbon group” refers to linear and branched hydrocarbon groups, and “alicyclic hydrocarbon group” refers to cyclic hydrocarbon groups and / or cyclic hydrocarbon groups. This means a group to which a hydrogen group is bonded. The “aromatic hydrocarbon group” also includes a group in which a hydrocarbon group is bonded to an aromatic ring. When stereoisomers exist, all stereoisomers are included.
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.

〔resin〕
The resin of the present invention has a structural unit represented by formula (I) (hereinafter sometimes referred to as structural unit (I)) and a structural unit represented by formula (a3-4) (hereinafter referred to as “structural unit (a3)”. -4) ”))) (hereinafter also referred to as“ resin (A) ”).

<Structural unit (I)>
The structural unit (I) is represented by the following formula.
[In the formula (I),
R ¹ represents a hydrogen atom or a methyl group.
R ² and R ³ each independently represents a saturated hydrocarbon group having 1 to 6 carbon atoms.
Ar represents an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent. ]

Examples of the saturated hydrocarbon group for R ² and R ³ include an alkyl group, an alicyclic hydrocarbon group, and a group formed by a combination thereof.
Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group and the like.
The alicyclic hydrocarbon group may be monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

As the aromatic hydrocarbon group of Ar, phenyl group, naphthyl group, anthryl group, phenanthryl group, tolyl group, xylyl group, cumyl group, dimethylphenyl group, trimethylphenyl group, ethylphenyl group, propylphenyl group, butylphenyl group Aryl having 6 to 36 carbon atoms such as biphenyl group, triphenyl group, indenyl group, tetrahydronaphthyl group, p-adamantylphenyl group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group Groups.
The aromatic hydrocarbon group preferably has 6 to 24 carbon atoms, more preferably 6 to 18 carbon atoms, and still more preferably a phenyl group.
Examples of the substituent of the aromatic hydrocarbon group include a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alkylcarbonyloxy group having 2 to 18 carbon atoms, an arylcarbonyloxy group having 7 to 18 carbon atoms, or 2 to 18 carbon atoms. And —CH ₂ — contained in the alkoxy group having 1 to 12 carbon atoms may be replaced by —O—.
Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, decyloxy group, and dodecyloxy group, preferably 1 to 1 carbon atoms. 6 alkoxy groups are mentioned, More preferably, a methoxy group is mentioned.
Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropylcarbonyloxy group, an n-butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, Examples thereof include a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group and a 2-ethylhexylcarbonyloxy group, preferably an alkylcarbonyloxy group having 2 to 12 carbon atoms, more preferably a methylcarbonyloxy group. Can be mentioned.
Examples of the arylcarbonyloxy group include a phenylcarbonyloxy group and a tosylcarbonyloxy group, preferably an arylcarbonyloxy group having 7 to 12 carbon atoms, and more preferably a phenylcarbonyloxy group.
As alkoxycarbonyloxy group, methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, isopropoxycarbonyloxy group, n-butoxycarbonyloxy group, sec-butoxycarbonyloxy group, tert-butoxycarbonyloxy group A pentyloxycarbonyloxy group, a hexyloxycarbonyloxy group, an octyloxycarbonyloxy group, a 2-ethylhexyloxycarbonyloxy group, and the like, preferably an alkyloxycarbonyloxy group having 2 to 8 carbon atoms, and more preferably. Examples include tert-butyloxycarbonyloxy group.
As a substituent which Ar has, a hydroxy group is preferable.

Ar is preferably an aromatic hydrocarbon group which may have a substituent, more preferably an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent, and more preferably Is a phenyl group which may have a substituent or a naphthyl group which may have a substituent, and particularly preferably a phenyl group which may have a substituent.
R ¹ , R ² and R ³ are each independently preferably a methyl group or an ethyl group, and more preferably a methyl group.

Examples of the structural unit (I) include the structural units described below. The structural unit (I) is preferably a structural unit (I-1) to a structural unit (I-3), or a structural unit (I-7) to a structural unit (I-9).

In the structural unit, a structural unit in which a methyl group corresponding to R ¹ is replaced with a hydrogen atom can also be given as a specific example of the structural unit (I).

The content of the structural unit (I) is usually from 5 to 90 mol%, preferably from 10 to 85 mol%, more preferably from 10 to 80 mol%, based on all monomers in the resin (A). More preferably, it is 10-70 mol%.
The resin (A) may contain two or more structural units (I).

<Structural unit (a3-4)>
The structural unit (a3-4) is represented by the following formula.
[In the formula (a3-4),
R ^a24 represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
L ^a7 is a single bond, ^* —L ^a8 —O—, ^* —L ^a8 —CO—O—, ^* —L ^a8 —CO—O—L ^a9 —CO—O— or ^* —L ^a8 —O—CO ^-La9- O- is represented.
* Represents a bond with -O-.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
R ^a25 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
w1 represents an integer of 0 to 8. When w1 is 2 or more, the plurality of R ^a25 may be the same as or different from each other. ]

Examples of the aliphatic hydrocarbon group having 1 to 4 carbon atoms represented by ^Ra25 include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and a tert-butyl group. .
Examples of the halogen atom represented by R ^a24 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
^Examples of the alkyl group represented by ^Ra24 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group. Preferably, a C1-C4 alkyl group is mentioned, More preferably, a methyl group or an ethyl group is mentioned.
Examples of the alkyl group having a halogen atom represented by Ra ²⁴ include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluoro sec-butyl group, perfluorotert-butyl group, perfluoropentyl. Group, perfluorohexyl group, trichloromethyl group, tribromomethyl group, triiodomethyl group and the like.
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.

^Examples of the alkanediyl group represented by ^La8 and ^La9 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 and the like.
L ^a7 is preferably a single bond or ^* -L ^a8 —CO—O—, and more preferably a single bond, —CH ₂ —CO—O— or —C ₂ H ₄ —CO—O—.
R ^a25 is preferably a carboxy group, a cyano group, or a methyl group.
w1 is preferably an integer of 0 to 2, and more preferably 0 or 1.
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.)

Examples of the structural unit (a3-4) include the following structural units.

In the structural unit, a structural unit in which a methyl group corresponding to R ^a24 is replaced with a hydrogen atom can also be given as a specific example of the structural unit (a3-4).

The content rate of a structural unit (a3-4) is 10-95 mol% normally with respect to all the structural units of resin (A), Preferably it is 15-90 mol%, More preferably, it is 20-85 mol%. %.
Resin (A) may contain 2 or more types of structural units (a3-4).

  The resin (A) preferably further has a structural unit having an acid labile group (hereinafter sometimes referred to as “structural unit (a1)”). Here, the “acid labile group” means a group having a leaving group and forming a hydrophilic group (for example, a hydroxy group or a carboxy group) by leaving the leaving group by contact with an acid. .

<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 preferably a group represented by the formula (1) and / or a group represented by the formula (2).
[In the formula (1), R ^{a1 to} R ^a3 each independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a combination of these, or R ^a1 and R ^a2 are bonded to each other to form a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.
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. ]

^Examples of the alkyl group represented by R ^{a1 to} R ^a3 include a methyl group, an ethyl group, a propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, and an n-octyl group.
The alicyclic hydrocarbon group of R ^{a1 to} R ^a3 may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include 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 in which an alkyl group and an alicyclic hydrocarbon group are combined include, for example, methylcyclohexyl group, dimethylcyclohexyl group, methylnorbornyl group, cyclohexylmethyl group, adamantylmethyl group, adamantyldimethyl group, norbornyl 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.
When R ^{a2 ′} and R ^{a3 ′} are bonded to each other to form a divalent heterocyclic group formed together with the carbon atom to which they are bonded and X, —C (R ^{a1 ′} ) (R ^{a3 ′} ) —X—R ^{Examples of a2 ′} 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.

The group represented by the formula (1) is a 1,1-dialkylalkoxycarbonyl group (in the formula (1), R ^{a1 to} R ^a3 are alkyl groups, ma = 0, na = 1, preferably tert-butoxycarbonyl Group), 2-alkyladamantan-2-yloxycarbonyl group (in formula (1), R ^a1 , R ^a2 and the carbon atom to which they are bonded are adamantyl groups, R ^a3 is an alkyl group, ma = 0, na = 1 ) And 1- (adamantan-1-yl) -1-alkylalkoxycarbonyl group (in formula (1), R ^a1 and R ^a2 are alkyl groups, R ^a3 is an adamantyl group, ma = 0, na = 1), etc. Furthermore, the following groups are mentioned. * Represents a bond.

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

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

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

The structural unit derived from the (meth) acrylic monomer having a group represented by the formula (1) is preferably a structural unit represented by the formula (a1-0) (hereinafter referred to as the structural unit (a1-0)). The structural unit represented by the formula (a1-1) (hereinafter sometimes referred to as the structural unit (a1-1)) or the structural unit represented by the formula (a1-2) (hereinafter, And may be referred to as a structural unit (a1-2).). These may be used alone or in combination of two or more.
[In Formula (a1-0), Formula (a1-1) and Formula (a1-2),
L ^a01 , L ^a1 and L ^a2 each independently represent —O— or ^* —O— (CH ₂ ) _k1 —CO—O—, k1 represents 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 , R ^a04 , R ^a6 and R ^a7 is preferably 1 to 6, more preferably a methyl group or an ethyl group, and further preferably a methyl group.
Carbon number of the alicyclic hydrocarbon group of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 is preferably 3-8, more preferably 3-6.
The group in which the alkyl group and the alicyclic hydrocarbon group are combined preferably has a total carbon number of 18 or less in combination of the alkyl group and the alicyclic hydrocarbon group.
R ^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.
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 monomer which introduce | transduces structural unit (a1-1), 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%.

As the structural unit (a1) having a group represented by the group (2), a structural unit represented by the formula (a1-4) (hereinafter sometimes referred to as “structural unit (a1-4)”). Can be mentioned.
[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 acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or Represents a methacryloyloxy group.
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 And 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— Alternatively, it may be replaced by -S-. ]

^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, n-pentyl group, n-hexyl group, n -A perfluorohexyl group etc. are 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 acyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, and a butyryloxy group.
The R ^a34 and R ^a35, include the same groups as R ^{a1 'and} R ^a2' of formula (2).
^Ra36 includes an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group formed by combining these. It is done.

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 a hydrocarbon group having 1 to 12 carbon atoms, 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. When the aromatic hydrocarbon group in R ^a36 has a substituent, the substituent is preferably an aryloxy group having 6 to 10 carbon atoms.

Examples of the monomer for deriving the structural unit (a1-4) include monomers described in JP 2010-204646 A, preferably formula (a1-4-1) to formula (a1-4-7). And monomers represented by formulas (a1-4-1) to (a1-4-5) are more preferred.

  The resin (A) preferably has the structural unit (a1-4). When the resin has the structural unit (a1-4), the content is 10 with respect to the total of all the structural units of the resin (A). It is preferably -95 mol%, more preferably 15-90 mol%, still more preferably 20-85 mol%.

As a structural unit derived from a (meth) acrylic monomer having a group represented by the formula (2), a structural unit represented by the formula (a1-5) (hereinafter referred to as “structural unit (a1-5)”) Is also included).
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 monomer which introduce | transduces structural unit (a1-5), the monomer described in Unexamined-Japanese-Patent No. 2010-61117 is mentioned, for example. Among these, structural units 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.

  The resin (A) further includes a monomer having no acid labile group (hereinafter sometimes referred to as “monomer (s)”), a structural unit other than the structural unit (s), for example, the structural unit (a4), the structure The unit (a5) and / or other structural units derived from monomers known in the art may be contained.

<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 (a2) having a phenolic hydroxy group 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 acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or Represents a methacryloyloxy group.
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 any integer of 2 or more, the plurality of ^Ra51s may be the same as or different from each other. ]

^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, n-pentyl group, n-hexyl Groups and n-perfluorohexyl groups.
R ^a50 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, 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, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group.
^Examples of the alkoxy group for R ^a51 include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-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 acyl group for R ^a51 include an acetyl group, a propionyl group, and a butyryl group.
^Examples of the acyloxy 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 -. Among these, ^* —CO—O—, ^* —CO—O—A ^a52 —CO—O— or ^* —O—A ^a52 —CO—O— is preferable.

Examples of alkanediyl groups 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 preferably 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 hydroxyl group is preferably bonded to the o-position or p-position of the benzene ring, and more preferably bonded to the p-position.

Examples of the monomer for deriving the structural unit (a2-A) include monomers described in JP 2010-204634 A and JP 2012-12577 A.
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 (a2) having an alcoholic hydroxy group include a structural unit represented by the formula (a2-1) (hereinafter sometimes referred to as “structural unit (a2-1)”).
In formula (a2-1),
L ^a3 represents —O— or ^* —O— (CH ₂ ) _k2 —CO—O—,
k2 represents any integer of 1 to 7. * Represents a bond with -CO-.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 each independently represent a hydrogen atom, a methyl group or a hydroxy group.
o1 represents an integer of 0 to 10.

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

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. The structural unit represented by any one of formula (a2-1-1) to formula (a2-1-6) is 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%. More preferably, it is 1-35 mol%, More preferably, it is 2-20 mol%.

<Structural unit (a3)>
The lactone ring of the structural unit (a3) may be a monocycle such as a β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, or a condensed ring of a monocyclic lactone ring and another ring. But you can. Preferably, a bridged ring containing a γ-butyrolactone ring or 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), or the formula (a3-3). These 1 type may be contained independently and 2 or more types may be contained.

[In the formula (a3-1),
L ^a4 represents —O— or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7).
) Represents a group represented by * Represents a bond with a carbonyl group.
R ^a18 represents a hydrogen atom or a methyl group.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents any integer of 0 to 5. When p1 is 2 or more, the plurality of R ^a21 are the same or different from each other.
In formula (a3-2),
L ^a5 represents —O— or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7).
) Represents a group represented by * Represents a bond with a carbonyl group.
R ^a19 represents a hydrogen atom or a methyl group.
R ^a22 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
q1 represents any integer of 0 to 3. When q1 is 2 or more, the plurality of R ^a22 are the same or different from each other.
In formula (a3-3),
L ^a6 represents —O— or ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7).
) Represents a group represented by * Represents a bond with a carbonyl group.
R ^a20 represents a hydrogen atom or a methyl group.
R ^a23 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
r1 represents any integer of 0 to 3. When r1 is 2 or more, the plurality of R ^a23 are the same or different from each other. ]

Examples of the aliphatic hydrocarbon group for R ^a21 , R ^a22 and R ^a23 include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group and tert-butyl group. Can be mentioned.

In formula (a3-1) to formula (a3-3), L ^{a4 to} L ^a6 are preferably each independently, preferably —O— or k3 is an integer of 1 to 4 * —O—. A group represented by (CH ₂ ) _k3 —CO—O—, 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.

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

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

<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.

Examples of the structural unit (a4) include a structural unit represented by the formula (a4-1).
[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 aliphatic hydrocarbon group which may have a substituent.
A ^a43 represents a ^C1-C5 divalent aliphatic hydrocarbon group which may have a single bond or a substituent.
X ^a41 and X ^a42 each independently represent —O—, —CO—, ^—CO —O— or —O—CO—.
However, the total number of carbon atoms of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 7 or less. ]
* Represents a bond, and * on the right side represents a bond with —O—CO—R ^a42 . ]

^Examples of the hydrocarbon group for R ^a42 include chain and cyclic aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and groups formed by combining these.
The chain and cyclic aliphatic hydrocarbon groups may have a carbon-carbon unsaturated bond, but the chain and cyclic aliphatic saturated hydrocarbon groups are preferable. The aliphatic saturated hydrocarbon group includes a straight chain or branched alkyl group and a monocyclic or polycyclic alicyclic hydrocarbon group, and an aliphatic group formed by combining an alkyl group and an alicyclic hydrocarbon group. Group hydrocarbon group and the like.

Examples of chain aliphatic hydrocarbon groups include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and n-decyl. Group, n-dodecyl group, n-pentadecyl group, n-hexadecyl group, n-heptadecyl group and n-octadecyl group. Cyclic aliphatic hydrocarbon groups include cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group and other cycloalkyl groups; decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* is a bond) And a polycyclic alicyclic hydrocarbon group 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.

The hydrocarbon group for R ^a42 is preferably a chain or cyclic aliphatic hydrocarbon group or a group formed by a combination thereof, and may have a carbon-carbon unsaturated bond. And a cyclic aliphatic saturated hydrocarbon group and a group formed by combining these are more preferable.
R ^a42 includes a halogen atom or 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 C ^1-17 aliphatic hydrocarbon group having at least one halogen atom.
* Represents a bond. ]

^As the aliphatic hydrocarbon group for A ^a45, the same groups as those exemplified for R ^a42 can be mentioned.
R ^a42 is preferably an aliphatic hydrocarbon group which may have a halogen atom, more preferably an alkyl group having a halogen atom and / or an aliphatic hydrocarbon group having a group represented by the formula (a-g3). .
When R ^a42 is an aliphatic hydrocarbon group having a halogen atom, it is preferably an aliphatic hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, and still more preferably a carbon number. It is a 1-6 perfluoroalkyl group, Most preferably, it is a C1-C3 perfluoroalkyl group. Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, and a perfluorooctyl group. Examples of the perfluorocycloalkyl group include a perfluorocyclohexyl group.
When R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula (a-g3), including the carbon number contained in the group represented by the formula (a-g3), the aliphatic hydrocarbon The total carbon number of the group is preferably 15 or less, more preferably 12 or less. When it has a group represented by the formula (a-g3) as a substituent, the number is preferably 1.

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

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

A more preferred structure of the partial structure represented by * -A ^a46 -X ^a44 -A ^a47 (* represents a bond to a carbonyl group) is the following structure.

^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 aliphatic hydrocarbon group of A ^a42 , A ^a43 and A ^{a44 in} the group (a-g1) may have a carbon-carbon unsaturated bond, but a linear and cyclic aliphatic saturated hydrocarbon group In addition, groups formed by combining them are preferred. The aliphatic saturated hydrocarbon group is formed by combining a linear or branched alkyl group and a monocyclic or polycyclic alicyclic hydrocarbon group, and an alkyl group and an alicyclic hydrocarbon group. An aliphatic hydrocarbon group etc. are 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 aliphatic 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 ( ^{ag1) 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 ** represents 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 having a fluorine atom of R ^f22 includes chain and cyclic aliphatic hydrocarbon groups and aromatic hydrocarbon groups, and groups formed by combining them. As the aliphatic hydrocarbon group, an alkyl group (straight or branched) and an alicyclic hydrocarbon group are preferable.
Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group and 2 -An ethylhexyl group is mentioned.
The alicyclic hydrocarbon group may be monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, methylcyclohexyl group, dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, cycloheptyl group, and cyclodecyl group. A cycloalkyl group is mentioned. Examples of the polycyclic alicyclic hydrocarbon group include decahydronaphthyl group, adamantyl group, 2-alkyladamantan-2-yl group, 1- (adamantan-1-yl) alkane-1-yl group, norbornyl group, A methyl norbornyl group and an isobornyl group are mentioned.

^Examples of the hydrocarbon group having a fluorine atom for R ^f22 include an alkyl group having a fluorine atom and an alicyclic hydrocarbon group having a fluorine atom.
Examples of the alkyl group having a fluorine atom include a difluoromethyl group, a trifluoromethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, a 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, 1- (trifluoromethyl) -2,2,2-trifluoroethyl 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- (perfluoropropyl) 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, 2- (perfluoro Butyl) ethyl group, 1,1,2,2,3,3,4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,4,5,5 Fluorinated alkyl groups such as 6,6-dodecafluorohexyl group, perfluoropentylmethyl group and perfluorohexyl group can be mentioned.
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), as the _{^{A f21, - (CH 2)}} j1 - , more preferably an ethylene group or a methylene group, 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 them, the structural unit (a5) preferably includes a group having 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 the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group. ]

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

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

Examples of the group in which the methylene group contained in the saturated hydrocarbon group is replaced with an oxygen atom or a carbonyl group include groups represented by formulas (L1-1) to (L1-4). In the following formula, * represents a bond with an oxygen atom.
In formula (L1-1),
X ^x1 represents a carbonyloxy group or an oxycarbonyl group.
L ^x1 represents a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
L ^x2 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
However, the total carbon number of L ^x1 and L ^x2 is 16 or less.
In formula (L1-2),
L ^x3 represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms.
L ^x4 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
However, the total carbon number of L ^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 divalent alicyclic saturated hydrocarbon group having 3 to 10 carbon atoms, more preferably a cyclohexanediyl group or an adamantanediyl group.

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

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

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

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

L ⁵¹ is preferably a single bond or a group represented by 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%.

<Structural unit (II)>
The resin (A) may further contain a structural unit that decomposes upon exposure to generate an acid (hereinafter sometimes referred to as “structural unit (II)”. Specifically, Japanese Patent Application Laid-Open No. 2006-79235. Examples of the structural units described in the publication include structural units having a sulfonate group or a carboxylate group in the side chain (an organic cation as a counter ion for these groups is also included in the side chain) or a sulfonio group (-S ⁺ (R) (R ′)) is a structural unit (an organic anion as a counter ion for this group is also included in the side chain).

The structural unit having a sulfonate group or carboxylate group and an organic cation in the side chain is preferably a structural unit represented by the formula (II-2-A ′).
[In the formula (II-2-A ′)
X ^III3 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced by —O—, —S— or —CO—. The hydrogen atom contained in the saturated hydrocarbon group may be replaced with a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, or a hydroxy group.
A ^x1 represents an alkanediyl group having 1 to 8 carbon atoms, and a hydrogen atom contained in the alkanediyl group may be substituted with a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
RA ^- represents a sulfonate or carboxylate groups.
R ^III3 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
Z ^{a +} represents an organic cation. ]

Examples of the halogen atom represented by R ^III3 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
As the alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^III3 , an alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^a8 and The same can be mentioned.
Examples of the alkanediyl group having 1 to 8 carbon atoms represented by A ^x1 include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, and a pentane-1,5-diyl group. Hexane-1,6-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2, 4-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group, etc. Can be mentioned.

Examples of the divalent saturated hydrocarbon group having 1 to 18 carbon atoms represented by ^XIII3 include a linear or branched alkanediyl group, a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group. These may be combined.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1 , 6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group , Linear alkanediyl groups such as dodecane-1,12-diyl group; butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group Branched alkanediyl groups such as pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group; cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1 , 4-diyl group, Cycloalkanediyl group such as looctane-1,5-diyl group; norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane-2,6-diyl group Bivalent polycyclic alicyclic saturated hydrocarbon groups and the like.

Examples of the group in which —CH ₂ — contained in the saturated hydrocarbon group is replaced by —O—, —S—, or —CO— include divalent groups represented by formula (X1) to formula (X53), for example. Can be mentioned. However, the number of carbon atoms before —CH ₂ — contained in the saturated hydrocarbon group is replaced with —O—, —S—, or —CO— is 17 or less. In the following formulas, * represents a bond to ^{A x1.}

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

Examples of the organic cation represented by Z ^{a +} include organic onium cations such as organic sulfonium cation, organic iodonium cation, organic ammonium cation, organic benzothiazolium cation, and organic phosphonium cation. Organic sulfonium cation and organic iodonium cation Are preferred, and arylsulfonium cations are more preferred.
Specific examples include the same organic cations in the acid generator (B) described later.

The structural unit represented by the formula (II-2-A ′) is preferably a structural unit represented by the formula (II-2-A).
[In formula (II-2-A), R ^III3 , X ^III3 and Z ^{a +} represent the same meaning as described above.
Z represents an integer of 0 to 6.
R ^III2 and R ^III4 each independently represent a hydrogen atom, a fluorine atom or a C 1-6 perfluoroalkyl group, and when z is 2 or more, the plurality of R ^III2 and R ^III4 are the same as each other It may be different or different.
Q ^a and Q ^b each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group. ]

^{Examples of} the C 1-6 perfluoroalkyl group represented by R ^III2 , R ^III4 , Q ^a and Q ^b include the same as the C 1-6 perfluoroalkyl group represented by Q ¹ .

The structural unit represented by the formula (II-2-A) is preferably a structural unit represented by the formula (II-2-A-1).
[In the formula (II-2-A-1)
R ^III2 , R ^III3 , R ^III4 , Q ^a , Q ^b , z and Z ^{a +} represent the same meaning as described above.
R ^III5 represents a saturated hydrocarbon group having 1 to 12 carbon atoms.
X ² represents a divalent saturated hydrocarbon group having 1 to 11 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced by —O—, —S— or —CO—. The hydrogen atom contained in the saturated hydrocarbon group may be substituted with a halogen atom or a hydroxy group. ]

Examples of the saturated hydrocarbon group having 1 to 12 carbon atoms represented by R ^III5 include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, Examples thereof include linear or branched alkyl groups such as heptyl group, octyl group, nonyl group, decyl group, undecyl group and dodecyl group.
Examples of the divalent saturated hydrocarbon group having 1 to 11 carbon atoms represented by X ² include those having up to 11 carbon atoms in the divalent saturated hydrocarbon group represented by X ^III3 .

As the structural unit represented by the formula (II-2-A), a structural unit represented by the formula (II-2-A-2) is more preferable.
[In Formula (II-2-A-2), R ^III3 , R ^III5 and Z ^{a +} represent the same meaning as described above.
m and n each independently represent 1 or 2. ]

Examples of the structural unit represented by the formula (II-2-A-1) include the following structural units and the structural units described in WO2012 / 050015. Z ^{a +} represents an organic cation.

The structural unit having a sulfonio group and an organic anion in the side chain is preferably a structural unit represented by the formula (II-1-1).
[In the formula (II-1-1),
A ^II1 represents a single bond or a divalent linking group.
R ^II represents a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^II2 and R ^II3 each independently represent a hydrocarbon group having 1 to 18 carbon atoms, and R ^II2 and R ^II3 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.
R ^II4 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
A ⁻ represents an organic anion. ]
Examples of the divalent aromatic hydrocarbon group having 6 to 18 carbon atoms represented by R ^II1 include a phenylene group and a naphthylene group.
Examples of the hydrocarbon group having 1 to 18 carbon atoms represented by R ^II2 and ^{R II3,} include those similar to the hydrocarbon group having 1 to 18 carbon atoms represented by ^{R 1.}
Examples of the halogen atom represented by R ^II4 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
As the alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^II4 , an alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^a8 ; The same can be mentioned.
Examples of the divalent linking group represented by A ^II1 include a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group is: -O-, -S- or -CO- may be substituted. Specifically, the same thing as a C1-C18 bivalent saturated hydrocarbon group represented by ^XIII3 is mentioned.

Examples of the structural unit containing a cation in formula (II-1-1) include the structural units represented below.

A ^- The organic anion represented by a sulfonic acid anion, sulfonyl imide anion, methide anion and a carboxylate anion, and the like. A ^- organic anion represented by the sulfonate anion are preferable, and more preferably an anion contained in the later-described acid generator (B1).

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

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

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

The resin (A) is preferably a resin composed of the structural unit (I) and the structural unit (a3-4), and further includes a structural unit (s).
The structural unit (s) is preferably the structural unit (a2). The structural unit (a2) is preferably a structural unit represented by the formula (a2-A) or the formula (a2-1).

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

  As for the content rate of 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.

<Resist composition>
The resist composition of the present invention contains a resin (A) and an acid generator.
The resist composition preferably contains a quencher (hereinafter sometimes referred to as “quencher (C)”) and a solvent (hereinafter sometimes referred to as “solvent (E)”).

<Resin other than resin (A)>
The resist composition of the present invention may contain a resin other than the resin (A). Examples of such a resin include a resin containing a structural unit having a fluorine atom.
As the resin containing a structural unit having a fluorine atom, a resin containing the structural unit (a4) (hereinafter sometimes 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). .
The resin (X) preferably does not contain the structural unit (a1).
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 resin (X) is included, the content is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, and still more preferably 1 to 50 parts by mass with respect to 100 parts by mass of the resin (A). 40 parts by mass, particularly preferably 2 to 30 parts by mass.

  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 acid generator (B) may be either nonionic or ionic. Nonionic acid generators include organic halides, sulfonate esters (for example, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonate), and sulfones. (For example, disulfone, ketosulfone, sulfonyldiazomethane) and the like. Typical examples of the ionic acid generator include onium salts containing onium cations (for example, diazonium salts, phosphonium salts, sulfonium salts, and iodonium salts). Examples of the anion of the onium salt include a sulfonate anion, a sulfonylimide anion, and a sulfonylmethide anion.

  As the acid generator (B), JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038, JP-A-63-163452, Kaisho 62-153853, JP 63-146029, U.S. Pat. No. 3,779,778, U.S. Pat. No. 3,849,137, German Patent 3914407, European Patent 126,712, etc. The compound which generate | occur | produces an acid by the radiation as described in 1 can be used. Moreover, you may use the compound manufactured by the well-known method. Two or more acid generators (B) may be used in combination.

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

Examples of the perfluoroalkyl group of Q ¹ and Q ² include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, and a perfluoro group. A hexyl group etc. are mentioned.
Q ¹ and Q ² are preferably each independently a fluorine atom or a trifluoromethyl group, and more preferably a fluorine atom.

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

Examples of the group in which —CH ₂ — contained in the divalent saturated hydrocarbon group of L ^b1 is replaced by —O— or —CO— include any of formulas (b1-1) to (b1-3) The group represented by these is mentioned. In the formulas (b1-1) to (b1-3) and the following specific examples, * represents a bond with -Y.

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

In Formula (b1-1) to Formula (b1-3), when the methylene group contained in the saturated hydrocarbon group is replaced with an oxygen atom or a carbonyl group, the number of carbons before the replacement is represented by the carbon number of the saturated hydrocarbon group. It is a number.
Examples of the divalent saturated hydrocarbon group include the same divalent saturated hydrocarbon group of L ^b1.

L ^b2 is preferably a single bond.
L ^b3 is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.
L ^b4 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms, and the hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b6 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b7 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, The methylene group contained in the divalent saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.

As the group in which —CH ₂ — contained in the divalent saturated hydrocarbon group of L ^b1 is replaced by —O— or —CO—, a group represented by the formula (b1-1) or the formula (b1-3) Is preferred.
Examples of the group represented by the formula (b1-1) include the following.

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

Examples of the group represented by the formula (b1-3) include the following.

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

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

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

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

Examples of Y include the following.

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

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

  The sulfonate anion in the salt represented by the formula (B1) is an anion represented by the formula (B1-A-1) to the formula (B1-A-55) [hereinafter, anion (B1 -A-1) "or the like. ] Is preferable, Formula (B1-A-1)-Formula (B1-A-4), Formula (B1-A-9), Formula (B1-A-10), Formula (B1-A-24)-Formula It is represented by any one of (B1-A-33), formula (IA-36) to formula (IA-40), formula (B1-A-47) to formula (B1-A-55). An anion is more preferable.

Here, R ^{i2 to} R ⁱ⁷ are, for example, an alkyl group having 1 to 4 carbon atoms, preferably a methyl group or an ethyl group. R ⁱ⁸ is formed by, for example, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 5 to 12 carbon atoms, or a combination thereof. More preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group. L ⁴⁴ is a single bond or an alkanediyl group having 1 to 4 carbon atoms.
Q ¹ and Q ² are the same as described above.
Specific examples of the sulfonate anion in the salt represented by the formula (B1) include the anions described in JP 2010-204646 A.

  Examples of the sulfonate anion in the salt represented by Formula (B1) include anions represented by Formula (B1a-1) to Formula (B1a-34), respectively.

  Especially, Formula (B1a-1)-Formula (B1a-3) and Formula (B1a-7)-Formula (B1a-16), Formula (B1a-18), Formula (B1a-19), Formula (B1a-22) ) To (B1a-34) are preferable.

Examples of the organic cation of Z ⁺ include organic onium cations such as organic sulfonium cation, organic iodonium cation, organic ammonium cation, benzothiazolium cation, and organic phosphonium cation, and preferably organic sulfonium cation or organic iodonium cation. More preferably, an arylsulfonium cation is mentioned.
Z ⁺ in the formula (B1) is preferably a cation represented by any one of the formulas (b2-1) to (b2-4) [hereinafter referred to as “cation (b2-1)” or the like depending on the formula number, etc. There is a case. ].

[In Formula (b2-1)-Formula (b2-4),
R ^{b4 to} R ^b6 each independently represent 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 may be substituted with a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an acyl 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 form a ring together with the sulfur atom to which they are bonded, and —CH ₂ — contained in the ring may be replaced with —O—, —SO— or —CO—. .
R ^b7 and R ^b8 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently 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 form a ring together with the sulfur atom to which they are bonded, and —CH ₂ — contained in the ring may be replaced with —O—, —SO— or —CO—. .
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 together form a ring containing —CH—CO— to which they are bonded, and —CH ₂ — contained in the ring is —O—, —SO—. Alternatively, it may be replaced by -CO-.
R ^{b13 to} R ^b18 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
L ^b31 represents -S- or -O-.
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, the plurality of R ^b13 may be the same or different. When p2 is 2 or more, the plurality of R ^b14 may be the same or different. When q2 is 2 or more The plurality of R ^b15 may be the same or different. When r2 is 2 or more, the plurality of R ^b16 may be the same or different. When s2 is 2 or more, the plurality of R ^b17 is ^They may be the same or different, and when t2 is 2 or more, the plurality of R ^b18 may be the same or different. ]

Examples of the aliphatic hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group and 2-ethylhexyl group. Of the alkyl group. In particular, the aliphatic hydrocarbon group of 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 carbon number of the alicyclic hydrocarbon group of R ^{b9 to} R ^b12 is preferably 3 to 18, and more preferably 4 to 12.

  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-alkyladamantan-2-yl group, a methylnorbornyl group, and an isobornyl group. Groups 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 or the alicyclic hydrocarbon group having 3 to 18 carbon atoms is preferable.
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 acyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropylcarbonyloxy group, an n-butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, Examples thereof include a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group, and a 2-ethylhexylcarbonyloxy group.

The ring that R ^b4 and R ^b5 may form together with the sulfur atom to which they are bonded is any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. There may be. As this ring, a C3-C18 ring is mentioned, Preferably a C4-C18 ring is mentioned. Moreover, as a ring containing a sulfur atom, 3-membered ring-12-membered ring are mentioned, Preferably 3-membered ring-7-membered ring are mentioned, Specifically, the following ring is mentioned.

The ring formed by R ^b9 and R ^b10 together with the sulfur atom to which they are bonded may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. Good. Examples of the ring include 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) and thian-1-ium ring. Ring, 1,4-oxathian-4-ium ring and the like.
The ring formed by ^combining R ^b11 and R ^b12 may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. Examples of the ring include 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. It is done.

Among cations (b2-1) to cations (b2-4), cations (b2-1) are 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 acid generator (B1) is a combination of the above-described sulfonate anion and the above-mentioned organic cation, and these can be arbitrarily combined. The acid generator (B1) is preferably an anion and a cation (b2) represented by any one of formulas (B1a-1) to (B1a-3) and (B1a-7) to (B1a-16). -1) or a combination with a cation (b2-3).

Examples of the acid generator (B1) include those represented by formula (B1-1) to formula (B1-48), respectively, among which 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) and those represented by formulas (B1-31) to (B1-48) are preferable.

  In the resist composition of the present invention, the content of the acid generator is preferably 1 part by mass or more (more preferably 3 parts by mass or more), preferably 30 parts by mass or less with respect to 100 parts by mass of the resin (A). (More preferably 25 parts by mass 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)>
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 99% by mass or less in the resist composition. It is. 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)>
The resist composition of the present invention may contain a quencher (hereinafter sometimes referred to as “quencher (C)”). The quencher (C) may be a basic nitrogen-containing organic compound or a salt that generates an acid having a lower acidity than the acid generator (B).

<Basic nitrogen-containing organic compound>
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.

  Specifically, 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, Triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyl Cyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldinonylamine Decylamine, 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-methyl Imidazole, 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, and the like are preferable, diisopropylaniline is preferable, and 2,6-diisopropylaniline is particularly preferable.

  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.

<Salt that generates acid with low acidity>
The acidity in a salt that generates an acid having a weaker acidity than the acid generated from the acid generator is indicated by an acid dissociation constant (pKa). The salt that generates an acid having a weaker acidity than the acid generated from the acid generator is a salt in which the pKa of the acid generated from the salt is usually -3 <pKa, preferably -1 <pKa <7. More preferably, the salt is 0 <pKa <5. As a salt that generates an acid weaker than an acid generated from an acid generator (hereinafter sometimes referred to as “weak acid intramolecular salt (D)”), a salt represented by the following formula, JP-A-2015-147926 The weak acid inner salt represented by the formula (D) described in the gazette, JP 2012-229206 A, JP 2012-6908 A, JP 2012-72109 A, JP 2011-39502 A, and special Examples thereof include salts described in Japanese Unexamined Patent Publication No. 2011-191745.

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

  The content of the quencher (C) is preferably 0.01 to 5% by mass, more preferably 0.01 to 4% by mass, and particularly preferably 0.01 to 3% by mass in the solid content of the resist composition. % By mass.

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

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

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

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

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

The obtained composition layer is usually exposed using an exposure machine. The exposure machine may be an immersion exposure machine. 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, irradiating 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., and the development time is preferably 5 to 300 seconds. A positive resist pattern or a negative resist pattern can be produced by selecting the type of developer as follows.

When 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 includes a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure, or a resist composition for EUV exposure, particularly an electron. It is suitable as a resist composition for line (EB) exposure or a resist composition for EUV exposure, and is useful for fine processing of semiconductors.

The present invention will be described more specifically with reference to examples. In the examples, “%” and “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 under the following conditions.
Apparatus: HLC-8120GPC type (manufactured by Tosoh Corporation)
Column: TSKgel Multipore H _XL -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)

Resin Synthesis The compounds (monomers) used in the resin synthesis are shown below. Hereinafter, these monomers are referred to as “monomer (a1-1-1)” according to the formula number.

Example 1 [Synthesis of Resin A1]
As the monomer, monomer (a1-4-2), monomer (I-1), monomer (a2-1-4), monomer (a3-4-2) and monomer (II-2-A-1-1) Molar ratio [monomer (a1-4-2): monomer (I-1): monomer (a2-1-4): monomer (a3-4-2): monomer (II-2-A-1-) 1)] is mixed at a ratio of 25: 39: 5: 28: 3, and 1.5 mass times of methyl isobutyl ketone is mixed with this monomer mixture with respect to the total mass of all monomers. did. To the obtained mixture, azobisisobutyronitrile as an initiator was added so as to be 7 mol% with respect to the total number of moles of all monomers, and this was heated at 85 ° C. for about 5 hours to polymerize. Went. Thereafter, a p-toluenesulfonic acid aqueous solution was added to the polymerization reaction solution, and the mixture was stirred for 6 hours, followed by liquid separation. The recovered organic layer was poured into a large amount of n-heptane to precipitate a resin, and filtered and recovered to obtain Resin A1 having a weight average molecular weight of about 6.3 × 10 ³ in a yield of 72%. This resin A1 has the following structural units.

Example 2 [Synthesis of Resin A2]
As the monomer, monomer (a1-4-2), monomer (I-1), monomer (a2-1-4) and monomer (a3-4-2) were used, and their molar ratio [monomer (a1-4-2) ): Monomer (I-1): Monomer (a2-1-4): Monomer (a3-4-2)] is the same as Resin A1 except that the ratio is 28: 39: 5: 28. By this method, a resin A2 having a weight average molecular weight of about 6.1 × 10 ³ was obtained in a yield of 82%. This resin A2 has the following structural units.

Example 3 [Synthesis of Resin A3]
As the monomer, monomer (a1-4-2), monomer (I-2), monomer (a2-1-4) and monomer (a3-4-2) were used, and their molar ratio [monomer (a1-4-2) ): Monomer (I-2): Monomer (a2-1-4): Monomer (a3-4-2)] is the same as Resin A1 except that the ratio is 28: 39: 5: 28. By this method, a resin A3 having a weight average molecular weight of about 6.3 × 10 ³ was obtained in a yield of 80%. This resin A3 has the following structural units.

Example 4 [Synthesis of Resin A4]
As the monomer, monomer (a1-4-2), monomer (I-3), monomer (a2-1-4) and monomer (a3-4-2) were used, and the molar ratio [monomer (a1-4-2) ): Monomer (I-3): monomer (a2-1-4): monomer (a3-4-2)] is mixed in a ratio of 28: 39: 5: 28. By this method, a resin A4 having a weight average molecular weight of about 6.5 × 10 ³ was obtained in a yield of 76%. This resin A4 has the following structural units.

Example 5 [Synthesis of Resin A5]
As the monomer, monomer (a1-4-2), monomer (I-1), monomer (a1-1-3), monomer (a1-2-6), monomer (a2-1-4), monomer (a3- 4-2) and monomer (II-2-A-1-1), and the molar ratio [monomer (a1-4-2): monomer (I-1): monomer (a1-1-3): monomer (A1-2-6): monomer (a2-1-4): monomer (a3-4-2): monomer (II-2-A-1-1)] is 25: 15: 14: 10: 5 A resin A5 having a weight average molecular weight of about 6.8 × 10 ³ was obtained in a yield of 72% by the same method as that for the resin A1, except that the ratio was 28: 3. This resin A5 has the following structural units.

Example 6 [Synthesis of Resin A6]
As monomers, monomer (a1-4-2), monomer (I-1), monomer (a1-1-3), monomer (a1-2-6), monomer (a2-1-4) and monomer (a3- 4-2) and its molar ratio [monomer (a1-4-2): monomer (I-1): monomer (a1-1-3): monomer (a1-2-6): monomer (a2-1) -4): monomer (a3-4-2)] was mixed in a ratio of 28: 15: 14: 10: 5: 28 in the same manner as Resin A1, except that the weight average molecular weight was about 6 Resin A6 of .4 × 10 ³ was obtained with a yield of 71%. This resin A6 has the following structural units.

Example 7 [Synthesis of Resin A7]
As the monomer, monomer (a1-4-2), monomer (I-1), monomer (a1-2-6), monomer (a2-1-4) and monomer (a3-4-2) were used, and their moles The ratio [monomer (a1-4-2): monomer (I-1): monomer (a1-2-6): monomer (a2-1-4): monomer (a3-4-2)] is 28:15 A resin A7 having a weight average molecular weight of about 6.7 × 10 ³ was obtained in a yield of 86% by the same method as that for the resin A1, except that the ratio was 24: 5: 28. This resin A7 has the following structural units.

Example 8 [Synthesis of Resin A8]
As the monomer, monomer (I-2), monomer (a2-1-1) and monomer (a3-4-2) were used, and the molar ratio [monomer (I-2): monomer (a2-1-1): Monomer (a3-4-2)] is mixed at a ratio of 25:25:50, and further, 1.5 mass times of methyl isobutyl ketone is added to this monomer mixture with respect to the total mass of all monomers. Were mixed. To the resulting mixture, azobisisobutyronitrile as an initiator was added so as to be 5 mol% with respect to the total number of moles of all monomers, and this was heated at 85 ° C. for about 5 hours for polymerization. Went. 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 poured into a methanol / water mixed solvent and repulped, and this resin was filtered to obtain a resin A8 having a weight average molecular weight of 8.8 × 10 ^{3 in} a yield of 82%. This resin A8 has the following structural units.

Example 9 [Synthesis of Resin A9]
As the monomer, monomer (I-1), monomer (a2-1-1), monomer (a3-4-2) and monomer (II-2-A-2-1) were used, and their molar ratio [monomer (I -1): monomer (a2-1-1): monomer (a3-4-2): monomer (II-2-A-2-1)] in a ratio of 33: 18: 35: 14 Furthermore, 1.5 mass times of methyl isobutyl ketone was mixed with this monomer mixture with respect to the total mass of all monomers. To the resulting mixture, azobisisobutyronitrile as an initiator was added so as to be 6 mol% with respect to the total number of moles of all monomers, and this was heated at 85 ° C. for about 5 hours for polymerization. Went. 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 poured into a methanol / water mixed solvent and repulped, and this resin was filtered to obtain Resin A9 having a weight average molecular weight of about 7.5 × 10 ³ in a yield of 65%. This resin A9 has the following structural units.

Example 10 [Synthesis of Resin A10]
As the monomer, the monomer (a1-4-2), the monomer (I-7), the monomer (a2-1-4) and the monomer (a3-4-2) were used, and their molar ratio [monomer (a1-4-2) ): Monomer (I-7): Monomer (a2-1-4): Monomer (a3-4-2)] is the same as Resin A1 except that the ratio is 28: 39: 5: 28. By this method, a resin A10 having a weight average molecular weight of about 6.1 × 10 ³ was obtained with a yield of 78%. This resin A10 has the following structural units.

Example 11 [Synthesis of Resin A11]
As the monomer, monomer (a1-4-2), monomer (I-7), monomer (a2-1-1) and monomer (a3-4-2) were used, and their molar ratio [monomer (a1-4-2) ): Monomer (I-7): Monomer (a2-1-1): Monomer (a3-4-2)] is the same as Resin A1 except that the ratio is 28: 39: 5: 28. By this method, a resin A11 having a weight average molecular weight of about 6.2 × 10 ³ was obtained in a yield of 75%. This resin A11 has the following structural units.

Example 12 [Synthesis of Resin A12]
As the monomer, the monomer (a1-4-2), the monomer (I-8), the monomer (a2-1-4) and the monomer (a3-4-2) were used, and their molar ratio [monomer (a1-4-2) ): Monomer (I-8): Monomer (a2-1-4): Monomer (a3-4-2)] is the same as Resin A1 except that the ratio is 28: 39: 5: 28. By this method, a resin A12 having a weight average molecular weight of about 5.9 × 10 ³ was obtained in a yield of 76%. This resin A12 has the following structural units.

Example 13 [Synthesis of Resin A13]
As the monomer, the monomer (a1-4-2), the monomer (I-8), the monomer (a2-1-1) and the monomer (a3-4-2) were used, and the molar ratio [monomer (a1-4-2) ): Monomer (I-8): monomer (a2-1-1): monomer (a3-4-2)] is mixed in a ratio of 28: 39: 5: 28. By this method, a resin A13 having a weight average molecular weight of about 6.0 × 10 ³ was obtained in a yield of 73%. This resin A13 has the following structural units.

Example 14 [Synthesis of Resin A14]
As the monomer, monomer (a1-4-2), monomer (I-1), monomer (a2-1-1) and monomer (a3-4-2) were used, and their molar ratio [monomer (a1-4-2) ): Monomer (I-1): monomer (a2-1-1): monomer (a3-4-2)] is mixed in a ratio of 28: 39: 5: 28. By the method, a resin A14 having a weight average molecular weight of about 6.2 × 10 ³ was obtained in a yield of 80%. This resin A14 has the following structural units.

Example 15 [Synthesis of Resin A15]
As the monomer, monomer (a1-4-2), monomer (I-1), monomer (a2-1-3) and monomer (a3-4-2) were used, and their molar ratio [monomer (a1-4-2) ): Monomer (I-1): monomer (a2-1-3): monomer (a3-4-2)] is the same as the resin A1 except that the ratio is 28: 39: 5: 28. By this method, a resin A15 having a weight average molecular weight of about 6.0 × 10 ³ was obtained in a yield of 72%. This resin A15 has the following structural units.

Example 16 [Synthesis of Resin A16]
As the monomer, monomer (a1-4-2), monomer (I-7), monomer (a2-1-3) and monomer (a3-4-2) were used, and their molar ratio [monomer (a1-4-2) ): Monomer (I-7): Monomer (a2-1-3): Monomer (a3-4-2)] is the same as Resin A1 except that the ratio is 28: 39: 5: 28. By the method, a resin A16 having a weight average molecular weight of about 6.0 × 10 ³ was obtained with a yield of 70%. This resin A16 has the following structural units.

Example 17 [Synthesis of Resin A17]
As the monomer, the monomer (a1-4-2), the monomer (I-1) and the monomer (a3-4-2) are used, and the molar ratio thereof [monomer (a1-4-2): monomer (I-1): The resin A17 having a weight average molecular weight of about 5.8 × 10 ³ was collected in the same manner as the resin A1 except that the monomer (a3-4-2)] was mixed at a ratio of 38:42:20. Obtained at a rate of 78%. This resin A17 has the following structural units.

Example 18 [Synthesis of Resin A18]
As the monomer, the monomer (a1-4-2), the monomer (I-7), and the monomer (a3-4-2) were used, and the molar ratio [monomer (a1-4-2): monomer (I-7): The resin A18 having a weight average molecular weight of about 5.7 × 10 ³ is collected in the same manner as the resin A1 except that the monomer (a3-4-2)] is mixed so as to have a ratio of 38:42:20. Obtained at a rate of 73%. This resin A18 has the following structural units.

Example 19 [Synthesis of Resin A19]
As the monomer, monomer (a1-4-2), monomer (I-1), monomer (a1-1-3), monomer (a1-2-6) and monomer (a3-4-2) were used, and their moles The ratio [monomer (a1-4-2): monomer (I-1): monomer (a1-1-3): monomer (a1-2-6): monomer (a3-4-2)] is 33:17 The resin A19 having a weight average molecular weight of about 6.2 × 10 ³ was obtained in a yield of 65% by the same method as that for the resin A1, except that the ratio was 20:10:20. This resin A19 has the following structural units.

Example 20 [Synthesis of Resin A20]
As the monomer, monomer (a1-4-2), monomer (I-7), monomer (a1-1-3), monomer (a1-2-6) and monomer (a3-4-2) were used, and their moles The ratio [monomer (a1-4-2): monomer (I-7): monomer (a1-1-3): monomer (a1-2-6): monomer (a3-4-2)] is 33:17 A resin A20 having a weight average molecular weight of about 6.4 × 10 ³ was obtained in a yield of 63% by the same method as that for the resin A1, except that the ratio was 20:10:20. This resin A20 has the following structural units.

Synthesis Example 1 [Synthesis of Resin AX1]
As the monomer, monomer (I-2), monomer (a2-1-1) and monomer (a3-x) were used, and the molar ratio thereof [monomer (I-2): monomer (a2-1-1): monomer ( a3-x)] was obtained by the same method as that for Resin A8 except that it was mixed at a ratio of 25:25:50 to obtain Resin AX1 having a weight average molecular weight of 8.9 × 10 ^{3 in} a yield of 85%. This resin AX1 has the following structural units.

Synthesis Example 2 [Synthesis of Resin AX2]
As the monomer, monomer (I-1), monomer (a2-1-1), monomer (a3-1-1) and monomer (II-2-A-2-1) were used, and their molar ratio [monomer (I -1): monomer (a2-1-1): monomer (a3-1-1): monomer (II-2-A-2-1)] in a ratio of 33: 18: 35: 14 A resin AX2 having a weight average molecular weight of about 7.7 × 10 ³ was obtained in a yield of 62% by the same method as that for the resin A9 except for mixing. This resin AX2 has the following structural units.

<Preparation of resist composition>
A mixture obtained by mixing and dissolving the components shown in Table 1 was filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

<Resin>
A1 to A20: Resin A1 to Resin A20
A2: Resin A2
<Acid generator (B)>
B1-25: salt represented by formula (B1-25); synthesized by the method described in JP2011-126869A
<Quencher (C)>
C1: synthesized by the method described in JP2011-39502A
<Solvent>
Propylene glycol monomethyl ether acetate 400 parts Propylene glycol monomethyl ether 150 parts γ-butyrolactone 5 parts

(Electron beam exposure evaluation of resist composition: alkali development)
A 6-inch silicon wafer was treated on a direct hot plate with hexamethyldisilazane at 90 ° C. for 60 seconds. This silicon wafer was spin-coated with a resist composition so that the film thickness of the composition layer was 0.04 μm. Thereafter, the composition layer was formed by pre-baking on a direct hot plate for 60 seconds at the temperature shown in the “PB” column of Table 1. A line-and-space pattern was directly drawn on the composition layer formed on the wafer using an electron beam drawing machine ("HL-800D 50 keV" manufactured by Hitachi, Ltd.) while changing the exposure stepwise. .
After exposure, post exposure baking is performed for 60 seconds on the hot plate at the temperature shown in the “PEB” column of Table 1, and then paddle development is performed for 60 seconds with an aqueous 2.38 mass% tetramethylammonium hydroxide solution. A resist pattern was obtained.
The obtained resist pattern (line and space pattern) was observed with a scanning electron microscope, and the exposure amount at which the line width and space width of the 60 nm line and space pattern were 1: 1 was defined as effective sensitivity.

  Line edge roughness evaluation (LER): The width of unevenness on the side wall surface of a resist pattern manufactured with effective sensitivity was measured with a scanning electron microscope to determine line edge roughness. The results are shown in Table 2.

(Electron beam exposure evaluation of resist composition: organic solvent development)
A 6-inch silicon wafer was treated on a direct hot plate with hexamethyldisilazane at 90 ° C. for 60 seconds. This silicon wafer was spin-coated with a resist composition so that the film thickness of the composition layer was 0.04 μm. Thereafter, the composition layer was formed by pre-baking on a direct hot plate for 60 seconds at the temperature shown in the “PB” column of Table 1. A line-and-space pattern was directly drawn on the composition layer formed on the wafer using an electron beam drawing machine ("HL-800D 50 keV" manufactured by Hitachi, Ltd.) while changing the exposure stepwise. .
After the exposure, a post-exposure bake was performed for 60 seconds on the hot plate at the temperature shown in the “PEB” column of Table 1, and then the composition layer on the silicon wafer was treated with butyl acetate (Tokyo Chemical Industry ( The negative resist pattern was manufactured by performing development at 23 ° C. for 20 seconds using a dynamic dispensing method.
The obtained resist pattern (line and space pattern) was observed with a scanning electron microscope, and the exposure amount at which the line width and space width of the 60 nm line and space pattern were 1: 1 was defined as effective sensitivity.

  Line edge roughness evaluation (LER): The width of unevenness on the side wall surface of a resist pattern manufactured with effective sensitivity was measured with a scanning electron microscope to determine line edge roughness. The results are shown in Table 3.

  Since the salt, acid generator and resist composition of the present invention are excellent in line edge roughness (LER) of the resulting resist pattern, they are suitable for fine processing of semiconductors and are extremely useful industrially.

Claims (6)

A resin comprising a structural unit represented by formula (I) and a structural unit represented by formula (a3-4).
[In the formula (I),
R ¹ represents a hydrogen atom or a methyl group.
R ² and R ³ each independently represents a saturated hydrocarbon group having 1 to 6 carbon atoms.
Ar represents an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent. ]
[In the formula (a3-4),
R ^a24 represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
L ^a7 is a single bond, ^* —L ^a8 —O—, ^* —L ^a8 —CO—O—, ^* —L ^a8 —CO—O—L ^a9 —CO—O— or ^* —L ^a8 —O—CO ^-La9- O- is represented.
* Represents a bond with -O-.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
R ^a25 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
w1 represents an integer of 0 to 8. When w1 is 2 or more, the plurality of R ^a25 may be the same as or different from each other. ] The resin according to claim 1, wherein R ² and R ³ are each independently a methyl group or an ethyl group.   The resin according to claim 1 or 2, wherein Ar is a phenyl group which may have a substituent.   A resist composition containing the resin according to claim 1 and an acid generator.   The resist composition according to claim 4, further comprising a salt that generates an acid having a lower acidity than an acid generated from the acid generator. (1) The process of apply | coating the resist composition of Claim 4 or 5 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including: