JP2020033555A - Resin, resist composition, and method for producing resist pattern - Google Patents

Abstract

To provide a resin and a resist composition capable of producing a resist pattern having good resolution.SOLUTION: The resin contains: a structural unit represented by formula (I); a structural unit having a group represented by formula (II-x); at least one structural unit selected from the group consisting of a structural unit represented by formula (a1-1) and a structural unit represented by formula (a1-2); and a structural unit represented by formula (a2-A). The resist composition contains the resin.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 having the following structural unit.
Patent Document 2 describes a resist composition containing a resin having the following structural unit.
Patent Document 3 discloses a resist composition containing a resin having the following structural unit.

JP-A-2002-214788 JP 2013-205811 A JP 2011-148967 A

  The present invention provides a resin that forms a resist pattern having better resolution than a resist pattern formed by a resist composition containing the above resin.

The present invention includes the following inventions.
[1] A structural unit represented by the formula (I), a structural unit having a group represented by the formula (II-x), a structural unit represented by the formula (a1-1), and a structural unit represented by the formula (a1-2) A) a resin comprising at least one structural unit selected from the group consisting of structural units represented by formula (a) and a structural unit represented by formula (a2-A):
[In the formula (I),
R ¹ represents a hydrogen atom or a methyl group.
A ¹ represents a single bond or ^* -CO-O-, and * represents a bonding site to the carbon atom to which -R ¹ is bonded.
R ² represents a halogen atom, a hydroxy group, a haloalkyl group having 1 to 4 carbon atoms or an alkyl group having 1 to 12 carbon atoms, and -CH _2- contained in the alkyl group is -O- or -CO-. It may be replaced.
mi represents an integer of any of 1 to 3.
ni represents an integer of 0 to 4, when ni is 2 or more, plural R ² may be the same or different from each other. Here, mi + ni ≦ 5. ]
[In the formula (II-x),
Ring W ¹ represents a heterocyclic ring having 2 to 36 carbon atoms, and a hydrogen atom contained in the heterocyclic ring is a halogen atom, a hydroxy group, a hydrocarbon group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. may be substituted with an alkylcarbonyloxy group having 2 to 4 alkylcarbonyl group or a carbon number of 2 to 4 carbon atoms, -CH 2 contained in the heterocyclic and hydrocarbon groups _- is, -O-, -S -, - it may be replaced by CO- or NR ^c group.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ]
[In the formulas (a1-1) and (a1-2),
L ^a1 and ^{L a2} each independently, -O- or _{* -O- (CH 2) k1 -CO} -O- the stands, k1 represents an integer of 1-7, * the binding of -CO- Represent hand.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
m1 represents any integer of 0 to 14.
n1 represents any integer of 0-10.
n1 ′ represents any integer of 0 to 3. ]
[In the formula (a2-A),
^Ra50 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 represents a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl. Represents an oxy group or a methacryloyloxy group.
A ^a50 represents a single bond or ^{* -X a51 - (A a52 -X} a52) nb - represents, * represents a binding site to the carbon atom to which -R ^a50 binds.
A ^a52 represents an alkanediyl group having 1 to 6 carbon atoms.
X ^a51 and X ^a52 each independently represent -O-, ^-CO -O-, or -O-CO-.
nb represents 0 or 1.
mb represents any integer of 0-4. When mb is any integer of 2 or more, a plurality of R ^a51 may be the same or different. ]
[2] The resin according to [1], wherein the structural unit having a group represented by the formula (II-x) is a structural unit represented by the formula (IIA).
[In formula (IIA), ^Rx represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
A ^X is a single bond, ^{-A X1} - * or ^{-CO-O-A X1 - *} (* represents a binding position with a carbonyl group.) Represents the.
A ^X1 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, _-CH 2 contained in the saturated hydrocarbon group - is -O -, - CO- or -N ^{(R d)} - in It may be replaced.
Ring W ¹ represents a heterocyclic ring having 2 to 36 carbon atoms, and a hydrogen atom contained in the heterocyclic ring is a halogen atom, a hydroxy group, a hydrocarbon group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. may be substituted with an alkylcarbonyloxy group having 2 to 4 alkylcarbonyl group or a carbon number of 2 to 4 carbon atoms, -CH 2 contained in the heterocyclic and hydrocarbon groups _- is, -O-, -S -, - it may be replaced by CO- or NR ^c group.
R ^c and R ^d each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ]
[3] A resist composition comprising the resin according to [1] or [2] and an acid generator.
[4] The resist composition according to [3], wherein the acid generator contains a salt represented by the formula (B1).
[In the formula (B1),
Q ^b1 and Q ^b2 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. The hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Y represents a methyl group which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and-is included in the alicyclic hydrocarbon group. CH ₂ — may be replaced by —O—, —S (O) ₂ — or —CO—.
Z ⁺ represents an organic cation. ]
[5] The resist composition of [3] or [4], further comprising a salt that generates an acid having a lower acidity than the acid generated from the acid generator.
[6] (1) a step of applying the resist composition according to any one of [3] to [5] on a substrate;
(2) drying the composition after application to form a composition layer;
(3) a step of exposing the composition layer,
(4) A method for producing a resist pattern, comprising: a step of heating the composition layer after exposure; and (5) a step of developing the composition layer after heating.

  By using the resist composition containing the resin of the present invention, a resist pattern can be produced with good resolution.

In the present specification, unless otherwise specified, “(meth) acrylate” means “at least one selected from the group consisting of acrylates and methacrylates”. Notations such as "(meth) acrylic acid" and "(meth) acryloyl" have the same meaning. When a structural unit having “CH ₂ ＣC (CH ₃ ) —CO—” or “CH ₂ ＣＨCH—CO—” is exemplified, a structural unit having both groups is also exemplified. Shall be. The term “combined group” refers to a group obtained by combining two or more of the exemplified groups and changing their valences as appropriate. When stereoisomers are present, all stereoisomers are included.
In the present specification, the “solid content of the resist composition” means the sum of components excluding a solvent (E) described later from the total amount of the resist composition.

〔resin〕
The resin of the present invention comprises a structural unit represented by the formula (I) (hereinafter sometimes referred to as a structural unit (I)) and a structural unit having a group represented by the formula (II-x) It may be referred to as a structural unit (II), a structural unit represented by the formula (a1-1) (hereinafter, also referred to as a structural unit (a1-1)), and a formula (a1-2). At least one structural unit selected from the group consisting of a structural unit represented by the following formula (a1-2A) and a structural unit represented by the formula (a2-A) (Hereinafter sometimes referred to as “resin (A)”).

<Structural unit (I)>
In the formula (I), R ¹ is preferably a methyl group.
Examples of the halogen atom for R ² include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
The haloalkyl group having 1 to 4 carbon atoms in R ² represents an alkyl group having 1 to 4 carbon atoms having a halogen atom, and is a chloromethyl group, a bromomethyl group, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a perfluoro group. Butyl and the like.
Examples of the alkyl group having 1 to 12 carbon atoms for R ² include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, and a nonyl group. And an alkyl group. The carbon number of the alkyl group is preferably 1 to 9, more preferably 1 to 4.
When —CH ₂ — contained in the alkyl group represented by R ² is replaced by —O— or —CO—, the number of carbon atoms before the replacement is defined as the total number of carbon atoms of the alkyl group. R ² represents a hydroxy group (a group in which —CH ₂ — contained in a methyl group is replaced by —O—), a carboxyl group (—CH ₂ —CH ₂ — contained in an ethyl group represents —O— A group substituted by —CO—), an alkoxy group having 1 to 11 carbon atoms (a group in which —CH ₂ — contained in an alkyl group having 2 to 12 carbon atoms is replaced by —O—), (A group in which —CH ₂ —CH ₂ — contained in an alkyl group having 3 to 12 carbon atoms is replaced by —O—CO—), an alkylcarbonyl group having 2 to 12 carbon atoms (having 2 carbon atoms) A group in which —CH ₂ — contained in an alkyl group having 2 to 12 carbon atoms is replaced by —CO—; an alkylcarbonyloxy group having 2 to 11 carbon atoms (a group containing —CH _{2 —} contained in an alkyl group having 3 to 12 carbon atoms) -CH ₂ - is replaced by a -CO-O- Group).
Examples of the alkoxy group having 1 to 11 carbon atoms include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, octyloxy, 2-ethylhexyloxy, nonyloxy, decyloxy, undecyloxy And the like.
Examples of the alkoxycarbonyl group having 2 to 11 carbon atoms include a methoxycarbonyl group, an ethoxycarbonyl group, and a butoxycarbonyl group. Examples of the alkylcarbonyl group having 2 to 12 carbon atoms include an acetyl group, a propionyl group, and a butyryl group. Examples of the alkylcarbonyloxy group having 2 to 11 carbon atoms include an acetyloxy group, a propionyloxy group, and a butyryloxy group.
As R ² , among others, a halogen atom, a haloalkyl group having 1 to 4 carbon atoms or an alkyl group having 1 to 12 carbon atoms (-CH _2- contained in the alkyl group is replaced by -O- or -CO-. A fluorine atom, a haloalkyl group having 1 to 3 carbon atoms or an alkyl group having 1 to 6 carbon atoms (-CH _2- contained in the alkyl group is -O- or- (It may be replaced by CO-.).
mi is preferably 1 or 2.
ni is preferably any integer of 0 to 2, and more preferably 0.

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

In the structural units represented by the formulas (I-1) to (I-8), the structural units in which the hydrogen atom corresponding to R ¹ is replaced by a methyl group are also represented by the formulas (I-9) to (I-16). In the structural unit represented by (1), a structural unit in which the methyl group corresponding to R ¹ is replaced by a hydrogen atom can also be mentioned as a specific example of the structural unit (I). Among them, the structural units represented by the formulas (I-1) to (I-8), (I-9), and (I-11) are preferable, and the structural units represented by the formulas (I-1) to (I-I) are preferable. 4), the structural units represented by the formulas (I-9) and (I-11) are more preferable, and the structural units represented by the formulas (I-1), (I-3), (I-9) and (I-9) are more preferable. The structural unit represented by -11) is more preferable.

  The content of the structural unit (I) in the resin (A) is preferably from 3 to 80 mol%, more preferably from 5 to 60 mol%, even more preferably from 5 to 50 mol%, based on all structural units. Mol%, even more preferably 5 to 40 mol%.

<Structural unit (II)>
The structural unit (II) is a structural unit having a group represented by the formula (II-x), and is preferably a structural unit having a group represented by the formula (II-x) in a side chain.
[In the formula (II-x),
Ring W ¹ represents a heterocyclic ring having 2 to 36 carbon atoms, and a hydrogen atom contained in the heterocyclic ring is a halogen atom, a hydroxy group, a hydrocarbon group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. may be substituted with an alkylcarbonyloxy group having 2 to 4 alkylcarbonyl group or a carbon number of 2 to 4 carbon atoms, -CH 2 contained in the heterocyclic and hydrocarbon groups _- is, -O-, -S -, - it may be replaced by CO- or NR ^c group.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ]

Ring W ¹ represents a ring structure containing a nitrogen atom as a ring-constituting atom and one of the carbon atoms constituting the ring being a carbonyl group together with an oxo group (＝ O).
Heterocyclic ring ^{W 1} is eg, -CH ₂ constituting the ring - is, -O -, - S -, - CO- or may be further substituted such as NR ^c group. R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. The heterocyclic ring W ¹ may be an aromatic heterocyclic ring or a non-aromatic heterocyclic ring. It may be monocyclic or polycyclic.

The following formula
Specific examples of the group represented by are the following. * Represents a bond to the carbon atom of the carbonyl group.

The hydrogen atom contained in the heterocyclic ring having 2 to 36 carbon atoms represented by ring W ¹ is a halogen atom, a hydroxy group, a hydrocarbon group having 1 to 24 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, It may be substituted by 4 alkylcarbonyl groups or alkylcarbonyloxy groups having 2 to 4 carbon atoms.
Examples of the hydrocarbon group include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a combination thereof. —CH ₂ — contained in the hydrocarbon group is replaced by —O—, —S—, —CO—, an NR ^OF group ( ^ROF represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) and the like. However, it is preferable to substitute -O- or -CO-.
The aliphatic hydrocarbon group represents a chain hydrocarbon group and an alicyclic hydrocarbon group.
The chain hydrocarbon group may be saturated or unsaturated, and may be linear or branched. For example, linear saturated alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, pentadecyl group and hexadecyl group; isopropyl group, sec-butyl A branched saturated alkyl group such as a tert-butyl group and a 2-ethylhexyl group; an unsaturated linear alkyl group such as a vinyl group, a propenyl group, a hexenyl group and an octenyl group; and 3-methyl-2 And a branched unsaturated alkyl group such as -butenyl group.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, and a dimethylcyclohexane group. And cycloalkyl groups such as a xyl 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, a methylnorbornyl group, and the following groups.
Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group and an anthryl group.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, and an isobutyryloxy group.

The ring W ¹ is preferably a 4- to 7-membered heterocyclic ring containing a nitrogen atom or a heterocyclic ring containing the 4- to 7-membered ring. A heterocyclic ring containing a 6-membered ring is more preferable, and a 4- to 6-membered heterocyclic ring containing a nitrogen atom or a polycyclic structure containing the 4- to 6-membered heterocyclic ring is more preferable. -CO- are those that are positioned adjacent to the nitrogen atom, i.e. preferably the ring W ¹ is a lactam ring, and more preferably a lactam ring having a polycyclic structure.

The structural unit having a group represented by the formula (II-x) has a group derived from a polymerizable group. Examples of the polymerizable group include a vinyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, a methacryloyloxy group, an acryloylamino group, a methacryloylamino group, an acryloylthio group, and a methacryloylthio group.
Among them, the monomer that leads to the structural unit (II) is preferably a monomer having an ethylenically unsaturated bond, and more preferably a (meth) acrylic monomer.

The structural unit (II) is preferably a structural unit represented by the formula (IIA).
[In formula (IIA), ^Rx represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
A ^X is a single bond, ^{-A X1} - * or ^{-CO-O-A X1 - *} (* represents a binding position with a carbonyl group.) Represents the.
A ^X1 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, _-CH 2 contained in the saturated hydrocarbon group - is -O -, - CO- or -N ^{(R d)} - in It may be replaced.
Ring W ¹ represents a heterocyclic ring having 2 to 36 carbon atoms, and a hydrogen atom contained in the heterocyclic ring is a halogen atom, a hydroxy group, a hydrocarbon group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. may be substituted with an alkylcarbonyloxy group having 2 to 4 alkylcarbonyl group or a carbon number of 2 to 4 carbon atoms, -CH 2 contained in the heterocyclic and hydrocarbon groups _- is, -O-, -S -, - it may be replaced by CO- or NR ^c group.
R ^c and R ^d each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ]

Examples of the halogen atom for R ^x include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkyl group for R ^x 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. And preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group.
Examples of the alkyl group having a halogen atom for ^Rx include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, and a perfluoropentyl group. , A perfluorohexyl group, a trichloromethyl group, a tribromomethyl group and a triiodomethyl group.
R ^x is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and further preferably a hydrogen atom or a methyl group.

Examples of the divalent saturated hydrocarbon group of A ^X1, linear alkanediyl group, branched alkanediyl group, a divalent alicyclic saturated hydrocarbon group having a monocyclic or polycyclic and the like, these Two or more of the groups 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 , Dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1, Linear alkanediyl groups such as 17-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group and propane-2,2-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- A branched alkanediyl group such as a diyl group;
Monocyclic 2 which is a cycloalkanediyl group such as a cyclobutane-1,3-diyl group, a cyclopentane-1,3-diyl group, a cyclohexane-1,4-diyl group, a cyclooctane-1,5-diyl group; Divalent 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 and the like And the like.
A ^X1 is alkanediyl group having 1 to 6 carbon atoms _(-CH 2 contained in the alkanediyl group - is -O -, - CO- or -N ^{(R d)} - may be replaced with.) preferably, _-CH 2 in straight-chain alkanediyl group (the alkanediyl group having 1 to 4 carbon atoms - is, -O -, - CO- or -N ^{(R d)} - may be replaced by Is more preferred.
A ^X is a single _{bond, -CO-O- (CH 2)} gg - *, - CO-NH- (CH 2) gg - *, - CO-O- (CH 2) gg-O - * (* is , .gg representing the binding position of the carbonyl group is preferably represented) an integer of 1 to 4, a single _{bond, -CO-O- (CH 2)} gg -. * (* is Represents a bonding position with a carbonyl group, and gg represents an integer of any of 1 to 4.), and is more preferably a single bond.

Examples of the structural unit (II) include the following structural units.

In the structural units represented by the formulas (II-1) to (II-10), structural units in which a methyl group corresponding to R ^X is replaced by a hydrogen atom may also be mentioned as specific examples of the structural unit (II). it can. Among them, the structural units represented by the formulas (II-1) and (II-6) to (II-9) are preferable, and the structural units represented by the formulas (I-1) and (I-7) are preferable. Units are more preferred.

  The content of the structural unit (II) is preferably 1 to 50 mol%, more preferably 2 to 40 mol%, and still more preferably 3 to 4 mol%, based on the total of all the structural units of the resin (A). It is 30 mol%, particularly preferably 3 to 25 mol%.

<Structural unit (a1-1) and structural unit (a1-2)>
The structural unit (a1-1) and the structural unit (a1-2) are represented by the following formula.
[In the formulas (a1-1) and (a1-2),
L ^a1 and ^{L a2} each independently, -O- or _{* -O- (CH 2) k1 -CO} -O- the stands, k1 represents an integer of 1-7, and * -CO- Represents a bond with
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
m1 represents any integer of 0 to 14.
n1 represents any integer of 0-10.
n1 ′ represents any integer of 0 to 3. ]

R ^a4 and R ^a5 are preferably a methyl group.
L ^a1 and ^{L a2} are preferably oxygen atom or _{* -O- (CH 2) k01 -CO} -O- and is (however, k01 is preferably an integer of 1 to 4, more preferably 1 And more preferably an oxygen atom.
Examples of the alkyl group, the alicyclic hydrocarbon group, and the combination thereof in R ^a6 and R ^a7 include the same groups as those described in R ^a1 to R ^a2 and R ^a3 in Formula (1) described below. Can be
The alkyl group in ^Ra6 and ^Ra7 preferably has 1 to 6 carbon atoms, more preferably is a methyl group or an ethyl group, and further preferably is a methyl group.
The carbon number of the alicyclic hydrocarbon group of ^Ra6 and ^Ra7 is preferably 3 to 8, and more preferably 3 to 6.
The group obtained by combining the alkyl group and the alicyclic hydrocarbon group preferably has a total carbon number of 18 or less obtained by combining the alkyl group and the alicyclic hydrocarbon group.
^Ra6 and ^Ra7 are preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group, an ethyl group or an isopropyl group, and further preferably an ethyl group or an isopropyl group.
m1 is preferably an integer of any of 0 to 3, and more preferably 0 or 1.
n1 is preferably an integer of any of 0 to 3, and more preferably 0 or 1.
n1 ′ is preferably an integer of 0 to 2, more preferably 0 or 1.

Examples of the structural unit (a1-1) include a structural unit derived from a monomer described in JP-A-2010-204646. Above all, a methyl group corresponding to R ^a4 in the structural unit represented by any of the formulas (a1-1-1) to (a1-1-4) and the structural unit (a1-1) was replaced with a hydrogen atom. Structural units are preferable, and structural units represented by any of formulas (a1-1-1) to (a1-1-4) are more preferable.

  The content of the structural unit (a1-1) in the resin (A) is preferably 5 to 60 mol%, more preferably 5 to 50 mol%, and still more preferably 10 to 10 mol% based on all the structural units. To 45 mol%, and still more preferably 10 to 40 mol%.

The structural unit (a1-2) corresponds to the structural unit represented by any of the formulas (a1-2-1) to (a1-2-6) and R ^a5 in the structural unit (a1-2). Examples include a structural unit in which a methyl group is replaced by a hydrogen atom, and a structural unit represented by Formula (a1-2-2), Formula (a1-2-5), or Formula (a1-2-6) is preferable.

  The content of the structural unit (a1-2) in the resin (A) is preferably 5 to 60 mol%, more preferably 5 to 50 mol%, and still more preferably 10 to 10 mol%, based on all structural units. To 45 mol%, and still more preferably 10 to 40 mol%.

  The total content of the structural unit (a1-1) and the structural unit (a1-2) is usually 10 to 90 mol%, preferably 15 to 75 mol%, based on all structural units of the resin (A). Yes, more preferably 15 to 70 mol%, still more preferably 20 to 65 mol%, even more preferably 25 to 65 mol%.

<Structural unit (a2-A)>
The structural unit (a2-A) is represented by the following formula.
[In the formula (a2-A),
^Ra50 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 represents a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl. Represents an oxy group or a methacryloyloxy group.
A ^a50 represents a single bond or ^{* -X a51 - (A a52 -X} a52) nb - represents, * represents a bond to the carbon atom to which -R ^a50 binds.
A ^a52 represents an alkanediyl group having 1 to 6 carbon atoms.
X ^a51 and X ^a52 each independently represent -O-, ^-CO -O-, or -O-CO-.
nb represents 0 or 1.
mb represents any integer of 0-4. When mb is any integer of 2 or more, a plurality of R ^a51 may be the same or different. ]

^Examples of the halogen atom for R ^a50 include a fluorine atom, a chlorine atom, and a bromine atom.
^Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom in ^Ra50 include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, , 1,2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3 , 3,4,4-octafluorobutyl, butyl, perfluoropentyl, 2,2,3,3,4,4,5,5,5-nonafluoropentyl, pentyl, hexyl and perfluorohexyl Groups.
^Ra50 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, further preferably a hydrogen atom or a methyl group.
^Examples of the alkyl group for ^Ra51 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group.
^Examples of the alkoxy group for ^Ra51 include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, and a tert-butoxy group. An alkoxy group having 1 to 4 carbon atoms is preferred, a methoxy group or an ethoxy group is more preferred, and a methoxy group is even more preferred.
^Examples of the alkylcarbonyl group for ^Ra51 include an acetyl group, a propionyl group, and a butyryl group.
^Examples of the alkylcarbonyloxy group for ^Ra51 include an acetyloxy group, a propionyloxy group, and a butyryloxy group.
^Ra51 is preferably a methyl group.

^{* -X a51 - (A a52 -X} a52) nb - The, * - O -, * - CO-O -, * - O-CO -, * - CO-O-A a52 -CO-O-, * -O-CO- ^Aa52 -O-, * ^-OAa52 -CO-O-, * -CO- ^OAa52 -O- ^CO- , * -O-CO- ^Aa52- O-CO -. Especially, * -CO-O-, * -CO- ^OAa52- CO-O- or * ^-OAa52- CO-O- is preferable.
Examples of the alkanediyl group include methylene, ethylene, propane-1,3-diyl, propane-1,2-diyl, butane-1,4-diyl, pentane-1,5-diyl, and hexane-. 1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group and 2 -Methylbutane-1,4-diyl group and the like.
A ^a52 is preferably a methylene group or an ethylene group.
A ^a50 is preferably a single bond, * -CO-O- or * -CO-O-A ^a52 -CO-O-, and a single bond, * -CO-O- or * -CO-O-CH It is more preferably _2- CO-O-, even more preferably a single bond or * -CO-O-.
mb is preferably 0, 1 or 2, more preferably 0 or 1, and particularly preferably 0.
The hydroxy group is preferably bonded to the o- or p-position of the benzene ring, and more preferably bonded to the p-position.

Examples of the structural unit (a2-A) include structural units derived from monomers described in JP-A-2010-204634 and JP-A-2012-12577.
As the structural unit (a2-A), the structural units represented by the formulas (a2-2-1) to (a2-2-6) and the formulas (a2-2-1) to (a2-2-2-) In the structural unit represented by 6), a structural unit in which a methyl group corresponding to R ^a50 in the structural unit (a2-A) is replaced by a hydrogen atom is ^exemplified . The structural unit (a2-A) is a structural unit represented by the formula (a2-2-1), a structural unit represented by the formula (a2-2-3), or a structural unit represented by the formula (a2-2-6). A structural unit represented by the formula (a2-2-1), a structural unit represented by the formula (a2-2-3), or a structural unit represented by the formula (a2-2-6) Is preferably a structural unit in which the methyl group corresponding to R ^a50 in the structural unit (a2-A) has been replaced with a hydrogen atom.

The content of the structural unit (a2-A) in the resin (A) is preferably from 5 to 80 mol%, more preferably from 10 to 70 mol%, even more preferably from 10 to 70 mol% based on all the structural units. To 65 mol%, and still more preferably 10 to 60 mol%.
The structural unit (a2-A) can be included in the resin (A) by, for example, polymerizing using the structural unit (a1-4) described below, and then treating with an acid such as p-toluenesulfonic acid. . After polymerization using acetoxystyrene or the like, the resin (A) can be made to contain the structural unit (a2-A) by treating with an alkali such as tetramethylammonium hydroxide.

The resin (A) of the present invention comprises one structural unit other than the structural unit (I), the structural unit (II), the structural unit (a1-1), the structural unit (a1-2) and the structural unit (a2-A). A polymer containing the above may be used. As structural units other than the structural unit (I), the structural unit (II), the structural unit (a1-1), the structural unit (a1-2) and the structural unit (a2-A), the structural unit (a1-1), Structural unit (a1-2) and, if applicable, a structural unit having an acid labile group other than structural unit (II) and structural unit (a2-A) (hereinafter sometimes referred to as “structural unit (a1)”) A structural unit other than a structural unit having an acid labile group and having a halogen atom (hereinafter sometimes referred to as “structural unit (a4)”), a structural unit having no acid labile group (hereinafter referred to as “ Structural unit (s) "), a structural unit having a non-eliminable hydrocarbon group (hereinafter sometimes referred to as" structural unit (a5) "), and a structural unit which decomposes upon exposure to generate an acid (hereinafter referred to as" structural unit (s5) ") "Structural unit (III)"). It is.
Here, the acid labile group means a group that has a leaving group and forms a hydrophilic group (for example, a hydroxy group or a carboxy group) by leaving the leaving group upon 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) includes a group represented by the formula (1) (hereinafter, also referred to as a group (1)) and / or a group represented by the formula (2) (hereinafter, a group (2) ) Is also preferred.
[In the formula (1), R ^a1 , R ^a2 and R ^a3 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a combination thereof. R ^a1 and R ^a2 are bonded to each other to form an alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.
ma and na each independently represent 0 or 1, and at least one of ma and na represents 1.
* Represents a bond. ]
[In the 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 heterocyclic group having 3 to 20 carbon atoms together with the carbon atom and X to which they are bonded, and are included in the hydrocarbon group and the heterocyclic group; CH ₂ - may be replaced by -O- or -S-.
X represents an oxygen atom or a sulfur atom.
na ′ represents 0 or 1.
* Represents a bond. ]

The alkyl group in which R ^a1, R ^a2 and a ^{R a3,} a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group.
The alicyclic hydrocarbon group for R ^a1 , R ^a2 and R ^a3 may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include a cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups (* represents a bond). R ^a1, the number of carbon atoms in the alicyclic hydrocarbon group ^{R a2} and ^{R a3} is preferably 3 to 16.
Examples of a group obtained by combining an alkyl group and an alicyclic hydrocarbon group include, for example, a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, an adamantyldimethyl group, and a norbornyl group. And an ethyl group.
Preferably, ma is 0 and na is 1.
When R ^a1 and R ^a2 are bonded to each other to form an alicyclic hydrocarbon group, examples of —C (R ^a1 ) (R ^a2 ) (R ^a3 ) include the following groups. The alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms. * Represents a bond to -O-.

Examples of the hydrocarbon group for R ^{a1 ′} , R ^{a2 ′} and R ^{a3 ′} include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these.
Examples of the alkyl group and the alicyclic hydrocarbon group include the same groups as those described for R ^a1 , R ^a2, and R ^a3 .
Examples of the aromatic hydrocarbon group include aryl groups such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, and a phenanthryl group.
Examples of the combined group include a group obtained by combining the above-described alkyl group and an alicyclic hydrocarbon group (for example, a cycloalkylalkyl group), an aralkyl group (such as a benzyl group), and an aromatic hydrocarbon group having an alkyl group (p- Methylphenyl group, p-tert-butylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.), alicyclic hydrocarbon group And an aryl-cycloalkyl group (such as a phenylcyclohexyl group) and the like.
When R ^{a2 ′} and R ^{a3 ′} are bonded to each other to form a heterocyclic group together with the carbon atom to which they are bonded and X, —C (R ^{a1 ′} ) (R ^{a3 ′} ) —X—R ^{a2 ′} includes The following groups are mentioned. * Represents a bond.
It is preferable that at least one of R ^{a1 ′} and R ^{a2 ′} is a hydrogen atom.
na ′ is preferably 0.

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

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

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

The structural unit derived from the (meth) acrylic monomer having the group (1) is preferably a structural unit represented by the formula (a1-0) (hereinafter sometimes referred to as a structural unit (a1-0)). Is mentioned. These may be used alone or in combination of two or more.
[In the formula (a1-0),
L ^a01 is, -O- or _{^{* -O- (CH 2) k1 -CO}} -O- the stands, k1 represents an integer of 1-7, * represents a bond to -CO-.
R ^a01 represents 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. ]

^Ra01 is preferably a methyl group.
L ^a01 is preferably an oxygen atom or * -O- (CH ₂ ) _k01 -CO-O- (however, k01 is preferably an integer of any of 1 to 4, and more preferably 1). And more preferably an oxygen atom.
The alkyl group of R ^a02, R ^a03 and R ^a04, methyl, ethyl, propyl, n- butyl, n- pentyl, n- hexyl, n- heptyl, n- octyl group can be mentioned Can be
The alicyclic hydrocarbon group of ^Ra02 , ^Ra03 and ^Ra04 may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include a cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups (* represents a bond). R ^a02, R ^a03 and the number of carbon atoms in the alicyclic hydrocarbon group R ^a04 is preferably 3 to 16.
Examples of a group obtained by combining an alkyl group and an alicyclic hydrocarbon group include, for example, a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, an adamantyldimethyl group, and a norbornyl group. And an ethyl group.
The carbon number of the alicyclic hydrocarbon group of ^Ra02 , ^Ra03 and ^Ra04 is preferably 5 to 12, more preferably 5 to 10.
The group obtained by combining the alkyl group and the alicyclic hydrocarbon group preferably has a total carbon number of 18 or less obtained by combining the alkyl group and the alicyclic hydrocarbon group.
^Ra02 and ^Ra03 are preferably an alkyl group having 1 to 6 carbon atoms, more preferably a methyl group or an ethyl group.
^Ra04 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.

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

  When the resin (A) contains a structural unit (a1-0), its content is usually 5 to 60 mol%, preferably 5 to 50 mol%, based on all structural units of the resin (A). And more preferably 10 to 40 mol%.

Examples of the structural unit having the group (2) in the structural unit (a1) include a structural unit represented by the formula (a1-4) (hereinafter, may be referred to as “structural unit (a1-4)”). .
[In the formula (a1-4),
^Ra32 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 represents a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl. Represents an oxy group or a methacryloyloxy group.
la represents any integer of 0-4. When la is 2 or more, a plurality of ^Ra33 may be the same or different from each other.
R ^a34 and R ^a35 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^a36 may represent a hydrocarbon group having 1 to 20 carbon atoms, R ^a35 and R ^a36 are bonded to each other to with -C-O-which they are attached to form a divalent hydrocarbon group having 2 to 20 carbon atoms, -CH ₂ contained in the hydrocarbon group of the hydrocarbon group and the divalent - is - It may be replaced by O- or -S-. ]

^Examples of the alkyl group for ^Ra32 and ^Ra33 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 a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 2,2,2-trifluoroethyl group, 2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3 4,4-octafluorobutyl, butyl, perfluoropentyl, 2,2,3,3,4,4,5,5,5-nonafluoropentyl, pentyl, hexyl, perfluorohexyl, etc. No.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group and a hexyloxy group. Among them, an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is further preferable.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, and a butyryl group.
Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, and the like.
As the hydrocarbon group for R ^a34, R ^a35 and R ^a36, an alkyl group, an alicyclic hydrocarbon group, aromatic hydrocarbon group and a group formed by combining these are exemplified, as the alkyl group and alicyclic hydrocarbon groups Is the same as the alkyl group and the alicyclic hydrocarbon group in R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 .
Examples of the aromatic hydrocarbon group include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, and biphenyl. And aryl groups such as a phenanthryl group, a 2,6-diethylphenyl group and a 2-methyl-6-ethylphenyl group.
Examples of the combined group include a group obtained by combining the above-described alkyl group and alicyclic hydrocarbon group, an aralkyl group such as a benzyl group, and an aryl-cyclohexyl group such as a phenylcyclohexyl group. In particular, R ^a36 is an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group formed by combining these. Is mentioned.

In the formula (a1-4), R ^a32 is preferably a hydrogen atom.
As ^Ra33 , an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group and an ethoxy group are more preferable, and a methoxy group is further preferable.
As la, 0 or 1 is preferable, and 0 is more preferable.
^Ra34 is preferably a hydrogen atom.
^Ra35 is preferably an alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group, and more preferably a methyl group or an ethyl group.
The hydrocarbon group of ^Ra36 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 formed, more preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms. The alkyl group and the alicyclic hydrocarbon group for R ^a36 are preferably unsubstituted. Aromatic hydrocarbon group for R ^a36 is an aromatic ring preferably has an aryloxy group having 6 to 10 carbon atoms.
^{-OC (R a34) (R a35} ) -O-R a36 in the structural unit (a1-4) is desorbed by contact with an acid (e.g. p- toluenesulfonic acid) to form a hydroxy group.

Examples of the structural unit (a1-4) include a structural unit derived from a monomer described in JP-A-2010-204646. Preferably, hydrogen atom corresponding to R ^a32 in equation (a1-4-1) represented respectively to Formula (a1-4-12) structural units and structural units (a1-4) is replaced by a methyl group structure Units, and more preferably, structural units represented by formulas (a1-4-1) to (a1-4-5) and (a1-4-10).

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

Examples of the structural unit derived from the (meth) acrylic monomer having the group (2) also include a structural unit represented by the formula (a1-5) (hereinafter sometimes referred to as “structural unit (a1-5)”). Can be
In the formula (a1-5),
R ^a8 represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
Z ^a1 represents a single bond or _{* - (CH 2) h3 -CO} -L 54 - represents, h3 represents an integer of 1 to 4, * represents a bond to L ^51.
L ⁵¹ , L ⁵² , L ⁵³ and L ⁵⁴ each independently represent —O— or —S—.
s1 represents an integer of any of 1 to 3.
s1 ′ represents an integer from 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 the 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 of -O-, and is preferably other is -S-.
s1 is preferably 1.
s1 ′ is preferably an integer of 0 to 2.
Z ^a1 represents a single bond or * -CH ₂ -CO-O- are preferable.

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

  When the resin (A) has a structural unit (a1-5), its content is preferably from 1 to 50 mol%, more preferably from 3 to 45 mol%, based on all structural units of the resin (A). , 5 to 40 mol% is still more preferable, and 5 to 30 mol% is still more preferable.

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

Examples of the saturated hydrocarbon group for R ^x2 and R ^x3 include an alkyl group, an alicyclic hydrocarbon group, and a group formed by a combination thereof.
Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.
Examples of the aromatic hydrocarbon group of Ar ^x1 include aryl groups having 6 to 36 carbon atoms such as a phenyl group, a naphthyl group, and an anthryl group.
The aromatic hydrocarbon group preferably has 6 to 24 carbon atoms, more preferably has 6 to 18 carbon atoms, and still more preferably is a phenyl group.
Ar ^x1 is preferably an aromatic hydrocarbon group having 6 to 18 carbon atoms, more preferably a phenyl group or a naphthyl group, and further preferably a phenyl group.
Each of R ^x1 , R ^x2 and R ^x3 is independently preferably a methyl group or an ethyl group, and more preferably a methyl group.

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

When the resin (A) has the structural unit (a1-0X), its content is preferably from 5 to 60 mol%, more preferably from 5 to 50 mol%, based on all monomers in the resin (A). More preferably, it is more preferably 10 to 40 mol%.
The resin (A) may contain two or more structural units (a1-0X).

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

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

<Structural unit (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.
The structural unit (s) preferably has a hydroxy group or a lactone ring. Structure having a hydroxy group and not having an acid labile group (hereinafter sometimes referred to as “structural unit (a2)”) and / or having a lactone ring and having no acid labile group Use of a resin having units (hereinafter sometimes referred to as “structural unit (a3)”) in the resist composition of the present invention can improve the resolution of a resist pattern and the adhesion to a substrate.

<Structural unit (a2)>
Examples of the hydroxy group of the structural unit (a2) include an alcoholic hydroxy group, and examples of the structural unit (a2) include a structural unit (a2-1) described below. As the structural unit (a2), one type may be included alone, or two or more types may be included.

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

Formula (a2-1), L ^a3 is preferably, -O -, - O- (CH 2) f1 -CO-O- and is (wherein f1 represents an integer of 1 to 4) And more preferably -O-.
R ^a14 is preferably a methyl group.
^Ra15 is preferably a hydrogen atom.
^Ra16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of any of 0 to 3, more preferably 0 or 1.

Examples of the structural unit (a2-1) include a structural unit derived from a monomer described in JP-A-2010-204646. A structural unit represented by any of formulas (a2-1-1) to (a2-1-6) is preferable, and a structural unit represented by any of formulas (a2-1-1) to (a2-1-4) is preferable. The structural unit represented by the formula (a2-1-1) or the formula (a2-1-3) is more preferable.

  When the resin (A) contains the structural unit (a2-1), its content is usually from 1 to 45 mol%, preferably from 1 to 40 mol%, based on all the structural units of the resin (A). Yes, more preferably 1 to 35 mol%, still more preferably 1 to 20 mol%, and still more preferably 1 to 10 mol%.

<Structural unit (a3)>
The lactone ring contained in the structural unit (a3) may be a monocyclic ring such as a β-propiolactone ring, a γ-butyrolactone ring, a δ-valerolactone ring, or a monocyclic lactone ring and another ring (hydrocarbon ring). Or a heterocyclic ring). Preferably, a γ-butyrolactone ring, an adamantane lactone ring, or a bridged ring containing a γ-butyrolactone ring structure (for example, a structural unit represented by the following formula (a3-2)) is exemplified.

The structural unit (a3) is preferably a structural unit represented by the formula (a3-1), the formula (a3-2), the formula (a3-3) or the formula (a3-4). One of these may be contained alone, or two or more thereof may be contained.
[In the formula (a3-1), the formula (a3-2), the formula (a3-3) and the formula (a3-4),
L ^{a4, L a5} and ^{L a6} each independently, -O- or _{^{* -O- (CH 2) k3 -CO}} -O- (k3 represents. An integer of 1-7) is represented by Represents a group.
L ^{a7 is, -O-, * -O-L a8} -O-, * -O-L a8 -CO-O-, * -O-L a8 -CO-O-L a9 -CO-O- or ^* -O- ^La8- O-CO- ^La9- O- is represented.
^La8 and ^La9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
* Represents a bond to a carbonyl group.
R ^a18 , R ^a19 and R ^a20 each independently represent a hydrogen atom or a methyl group.
^Ra24 represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
^Ra21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
^Ra22 , ^Ra23 and ^Ra25 each independently represent a carboxy group, a cyano group or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
X ^a3 is, -CH ₂ - represents an or an oxygen atom.
p1 represents an integer of any of 0 to 5.
q1 represents any integer of 0 to 3.
r1 represents any integer of 0 to 3.
w1 represents an integer of any of 0 to 8.
When p1, q1, r1 and / or w1 are 2 or more, a plurality of R ^a21 , R ^a22 , R ^a23 and / or R ^a25 may be the same or different. ]

Examples of the aliphatic hydrocarbon group for R ^a21 , R ^a22 , R ^a23 and R ^a25 include alkyl groups such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group and a tert-butyl group. Can be
Examples of the halogen atom for ^Ra24 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
^Examples of the alkyl group for ^Ra24 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. And more preferably a methyl group or an ethyl group.
Examples of the alkyl group having a halogen atom in ^Ra24 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 perfluoropentyl group. Examples include a hexyl group, a trichloromethyl group, a tribromomethyl group, and a triiodomethyl group.
The alkanediyl group in ^La8 and ^La9 includes a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a pentane-1,5 -Diyl group, hexane-1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1, Examples include a 4-diyl group and a 2-methylbutane-1,4-diyl group.

In the formula (a3-1) ~ formula ^(a3-3), L a4 ^{~L a6} are each independently preferably -O- _{or, * - O- (CH 2)} k3 -CO-O- in, k3 Is a group represented by any integer of 1 to 4, more preferably —O— and * —O—CH ₂ —CO—O—, and still more preferably an oxygen atom.
^{Ra18 to Ra21} are preferably a methyl group.
^Ra22 and ^Ra23 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are each independently preferably an integer of 0 to 2, more preferably 0 or 1.

In the formula (a3-4), R ^a24 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, more preferably a hydrogen atom or a methyl group It is.
^Ra25 is preferably a carboxy group, a cyano group or a methyl group.
L ^a7 is preferably -O- or ^{* -O-L} a8 ^-CO-O-, more preferably an _{-O -, - O-CH 2} -CO-O- or _-O-C 2 _{H 4} - CO-O-.
w1 is preferably an integer of 0 to 2, more preferably 0 or 1.
Particularly, the formula (a3-4) is preferably the formula (a3-4) ′.
(In the formula, R ^a24 and L ^a7 represent the same meaning as described above.)

Examples of the structural unit (a3) include a monomer described in JP-A-2010-204646, a monomer described in JP-A-2000-122294, and a structure derived from a monomer described in JP-A-2012-41274. Units. As the structural unit (a3), the formula (a3-1-1), the formula (a3-1-2), the formula (a3-2-1), the formula (a3-2-2), the formula (a3-3-3) 1), a structural unit represented by any one of formulas (a3-3-2) and formulas (a3-4-1) to (a3-4-12), and the structural unit represented by the formula (a3-1) ) To a (a3-4), a structural unit in which a methyl group corresponding to R ^a18 , R ^a19 , R ^a20 and R ^a24 is replaced by a hydrogen atom is preferable.

When the resin (A) contains the structural unit (a3), its total content is usually 1 to 70 mol%, preferably 1 to 60 mol%, based on all structural units of the resin (A). , More preferably 1 to 50 mol%.
Further, the content of the structural unit (a3-1), the structural unit (a3-2), the structural unit (a3-3) or the content of the structural unit (a3-4) is respectively based on the total structural unit of the resin (A). Thus, 1 to 60 mol% is preferable, 1 to 50 mol% is more preferable, and 1 to 45 mol% is further preferable.

<Structural unit (a4)>
Examples of the structural unit (a4) include the following structural units.
[In the formula (a4),
R ⁴¹ represents a hydrogen atom or a methyl group.
R ⁴² represents a saturated hydrocarbon group having a fluorine atom having 1 to 24 carbon atoms, and —CH ₂ — contained in the saturated hydrocarbon group may be replaced by —O— or —CO. ]
Examples of the saturated hydrocarbon group represented by R ⁴² include a chain hydrocarbon group, a monocyclic or polycyclic alicyclic hydrocarbon group, and a group formed by combining these.

Examples of the chain hydrocarbon group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl. No.
Examples of the monocyclic or polycyclic alicyclic hydrocarbon group include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* Represents a bond), and polycyclic alicyclic hydrocarbon groups.
Examples of the group formed by the combination include a group formed by combining one or more alkyl groups or one or more alkanediyl groups with one or more alicyclic hydrocarbon groups. Alicyclic hydrocarbon group, -alicyclic hydrocarbon group-alkyl group, -alkanediyl group-alicyclic hydrocarbon group-alkyl group, and the like.

As the structural unit (a4), at least one selected from the group consisting of the formulas (a4-0), (a4-1), (a4-2), (a4-3), and (a4-4) And a structural unit represented by one.
[In the formula (a4-0),
R ^5a represents a hydrogen atom or a methyl group.
L ^4a represents a single bond or an alkanediyl group having 1 to 4 carbon atoms.
L ^3a represents a perfluoroalkyl cycloalkanediyl group perfluoro alkanediyl group or 3 to 12 carbon atoms having 1 to 8 carbon atoms.
R ^6a represents a hydrogen atom or a fluorine atom. ]

^Examples of the alkanediyl group for L ^4a include a linear alkanediyl group such as a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, an ethane-1,1-diyl group, And branched alkanediyl groups such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group. Can be
^Examples of the perfluoroalkanediyl group for L ^3a include a difluoromethylene group, a perfluoroethylene group, a perfluoropropane-1,1-diyl group, a perfluoropropane-1,3-diyl group, a perfluoropropane-1,2-diyl group, and a perfluoropropane group. -2,2-diyl group, perfluorobutane-1,4-diyl group, perfluorobutane-2,2-diyl group, perfluorobutane-1,2-diyl group, perfluoropentane-1,5-diyl group, perfluoropentane -2,2-diyl group, perfluoropentane-3,3-diyl group, perfluorohexane-1,6-diyl group, perfluorohexane-2,2-diyl group, perfluorohexane-3,3-diyl group, perfluoroheptane -1,7-diyl group, perfluoro Tan-2,2-diyl group, perfluoroheptane-3,4-diyl group, perfluoroheptane-4,4-diyl group, perfluorooctane-1,8-diyl group, perfluorooctane-2,2-diyl group, perfluoro An octane-3,3-diyl group, a perfluorooctane-4,4-diyl group and the like can be mentioned.
^Examples of the perfluorocycloalkanediyl group in L ^3a include a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, a perfluoroadamantanediyl group, and the like.
L ^4a is preferably a single bond, a methylene group or an ethylene group, and more preferably a single bond or a methylene group.
L ^3a is preferably a C 1-6 perfluoroalkanediyl group, more preferably a C 1-3 perfluoroalkanediyl group.

The structural unit (a4-0), a methyl group corresponding to R ^5a can be mentioned a structural unit replacing a hydrogen atom in the structural units in the structural units and the following structural units shown below (a4-0).

[In the formula (a4-1),
^Ra41 represents a hydrogen atom or a methyl group.
R ^a42 represents a saturated hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and —CH ₂ — contained in the saturated hydrocarbon group is replaced by —O— or —CO—. You may.
A ^a41 represents an ^optionally substituted alkanediyl group having 1 to 6 carbon atoms or a group represented by the formula (a-g1). However, at least one of A ^a41 and R ^a42 has a halogen atom (preferably a fluorine atom) as a substituent.
[In the formula (a-g1),
s represents 0 or 1.
A ^a42 and A ^a44 each independently represent a divalent saturated hydrocarbon group having 1 to 5 carbon atoms which may have a substituent.
A ^a43 represents a single bond or a divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a substituent.
X ^a41 and X ^a42 each independently represent -O-, -CO-, ^-CO -O-, or -O-CO-.
However, the total number of carbon atoms of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 7 or less. ]
* Is a bond, and * on the right side is a bond with -O-CO- ^Ra42 . ]

^Examples of the saturated hydrocarbon group for ^Ra42 include a chain saturated hydrocarbon group, a monocyclic or polycyclic alicyclic saturated hydrocarbon group, and a group formed by combining these.
Examples of the chain-type saturated hydrocarbon group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl. Is mentioned.
As the monocyclic or polycyclic alicyclic saturated hydrocarbon group, cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group and the following And a polycyclic alicyclic saturated hydrocarbon group such as a group (* represents a bond).
Examples of the group formed by the combination include a group formed by combining one or more alkyl groups or one or more alkanediyl groups with one or more saturated alicyclic hydrocarbon groups. -Saturated alicyclic hydrocarbon group, -saturated alicyclic hydrocarbon group-alkyl group, -alkanediyl group-saturated alicyclic hydrocarbon group-alkyl group, and the like.
^Examples of the substituent which ^Ra42 may have include at least one selected from the group consisting of a halogen atom and a group represented by the formula (a-g3). Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.
[In the formula (a-g3),
X ^a43 represents * ^-O- , * ^-CO- , * ^-O -CO- or * -CO-O- (* represents a bond to ^Ra42 ).
A ^a45 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
* Represents a bond. ]
However, in R ^a42 -X ^a43 -A ^a45, when R ^a42 has no halogen atom, A ^a45 represents an aliphatic hydrocarbon group of 1 to 17 carbon atoms and having at least one halogen atom.
^Examples of the aliphatic hydrocarbon group for A ^a45 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 decyl group, a dodecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group and An alkyl group such as an octadecyl group;
Monocyclic alicyclic hydrocarbon groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* represents a bond )) And other polycyclic alicyclic hydrocarbon groups.
Examples of the group formed by the combination include a group formed by combining one or more alkyl groups or one or more alkanediyl groups with one or more alicyclic hydrocarbon groups. Alicyclic hydrocarbon group, -alicyclic hydrocarbon group-alkyl group, -alkanediyl group-alicyclic hydrocarbon group-alkyl group, and the like.
R ^a42 is preferably a saturated hydrocarbon group ^optionally having a halogen atom, more preferably an alkyl group having a halogen atom and / or a saturated hydrocarbon group having a group represented by the formula (a-g3).
When R ^a42 is a saturated hydrocarbon group having a halogen atom, it is preferably a saturated hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, and further preferably a carbon number of 1 to 1. And is particularly preferably a perfluoroalkyl group having 1 to 3 carbon atoms. Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group and a perfluorooctyl group. Examples of the perfluorocycloalkyl group include a perfluorocyclohexyl group.
When ^Ra42 is a saturated hydrocarbon group having a group represented by the formula (a-g3), the total carbon number of ^Ra42 including the number of carbon atoms contained in the group represented by the formula (a-g3) The number 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 one.

When R ^a42 is a saturated hydrocarbon group having a group represented by the formula (a-g3), R ^a42 is more preferably a group represented by the formula (a-g2).
[In the formula (a-g2),
A ^a46 represents a divalent saturated hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
^Xa44 represents **-O-CO- or **-CO-O- (** represents a bond to ^Aa46 ).
A ^a47 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
However, the total number of carbon atoms of A ^a46 , A ^a47 and X ^a44 is 18 or less, and at least one of A ^a46 and A ^a47 has at least one halogen atom.
* Represents a bond to a carbonyl group. ]
The carbon number of the saturated hydrocarbon group for A ^a46 is preferably from 1 to 6, and more preferably from 1 to 3.
The number of carbon atoms of the aliphatic hydrocarbon group A ^a47 is preferably 4 to 15, more preferably from 5 to 12, A ^a47 is more preferably cyclohexyl group or adamantyl group.
The preferred structure of the group represented by the formula (a-g2) is the following structure (* is a bond to a carbonyl group).

^Examples of the alkanediyl group in A ^a41 include a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, and a hexane-1,6-diyl group. Linear alkanediyl groups 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 a branched alkanediyl group such as a 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.

As the divalent saturated hydrocarbon group represented by A ^a42 , A ^a43 and A ^{a44 in} the group represented by the formula (a-g1), a linear or branched alkanediyl group and a monocyclic or polycyclic divalent Examples thereof include an alicyclic hydrocarbon group, and a group formed by combining an alkanediyl group and a divalent alicyclic hydrocarbon group. Specifically, a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a 1-methylpropane-1,3-diyl group, Examples thereof include a 2-methylpropane-1,3-diyl group and a 2-methylpropane-1,2-diyl group.
^Examples of the substituent of the divalent saturated hydrocarbon group represented by A ^a42 , A ^a43 and A ^a44 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
s is preferably 0.
In the group represented by the formula (a-g1), ^{examples of the} group in which X ^a42 is —O—, ^—CO— , ^—CO —O—, or —O—CO— include the following groups. In the following examples, * and ** each represent a bond, and ** is a bond with -O-CO- ^Ra42 .

As the structural unit represented by the formula (a4-1), a methyl group corresponding to R ^a41 in the following structural unit and a structural unit represented by the formula (a4-1) in the following structural unit is a hydrogen atom. Replaced structural units.

As the structural unit represented by the formula (a4-1), a structural unit represented by the formula (a4-2) is preferable.
[In the formula (a4-2),
R ^f5 represents a hydrogen atom or a methyl group.
L ⁴⁴ represents an alkanediyl group having 1 to 6 carbon atoms, -CH ₂ contained in the alkanediyl group - may be replaced by -O- or -CO-.
R ^f6 represents a saturated hydrocarbon group having 1 to 20 carbon atoms and a fluorine atom.
However, the upper limit of the total number of carbon atoms of L ⁴⁴ and R ^f6 are 21. ]
Alkanediyl group of L ⁴⁴ include the same groups as those exemplified in A ^a41.
As the saturated hydrocarbon group for R ^f6 , the same groups as those exemplified for R ^a42 can be mentioned.
The alkanediyl group in L ^44, preferably alkanediyl group having 2 to 4 carbon atoms, and more preferably an ethylene group.
Examples of the structural unit represented by Formula (a4-2) include structural units represented by Formulas (a4-1-1) to (a4-1-11). A structural unit in which the methyl group corresponding to R ^f5 in the structural unit (a4-2) is replaced by a hydrogen atom is also exemplified as the structural unit represented by the formula (a4-2).

[In the formula (a4-3),
R ^f7 represents a hydrogen atom or a methyl group.
L ⁵ represents an alkanediyl group having 1 to 6 carbon atoms.
A ^f13 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms which may have a fluorine atom.
^Xf12 represents * -O-CO- or * -CO-O- (* represents a bond to ^Af13 ).
A ^f14 represents a C 1 to C 17 saturated hydrocarbon group which may have a fluorine atom.
However, at least one of A ^f13 and A ^f14 has a fluorine atom, and the upper limit of the total carbon number of L ⁵ , A ^f13 and A ^f14 is 20. ]

^Examples of the alkanediyl group for L ⁵ include the same groups as those exemplified for the alkanediyl group for A ^a41 .
As the divalent saturated hydrocarbon group ^optionally having a fluorine atom for A ^f13 , preferably a divalent chain-type saturated hydrocarbon group optionally having a fluorine atom or having a fluorine atom A divalent alicyclic saturated hydrocarbon group, and more preferably a perfluoroalkanediyl group.
Examples of the divalent chain hydrocarbon group which may have a fluorine atom include alkanediyl groups such as methylene group, ethylene group, propanediyl group, butanediyl group and pentanediyl group; difluoromethylene group, perfluoroethylene group, and perfluoroethylene group. And perfluoroalkanediyl groups such as a propanediyl group, a perfluorobutanediyl group and a perfluoropentanediyl group.
The divalent alicyclic hydrocarbon group which may have a fluorine atom may be either monocyclic or polycyclic. Examples of the monocyclic group include a cyclohexanediyl group and a perfluorocyclohexanediyl group. Examples of the polycyclic group include an adamantanediyl group, a norbornanediyl group, a perfluoroadamantanediyl group, and the like.
Or saturated hydrocarbon group which may have a saturated hydrocarbon group and a fluorine atom of A ^f14 include the same groups as those exemplified with R ^a42. Among them, trifluoromethyl group, difluoromethyl group, methyl group, perfluoroethyl group, 2,2,2-trifluoroethyl group, 1,1,2,2-tetrafluoroethyl group, ethyl group, perfluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3,4,4-octafluorobutyl group, butyl group, perfluoropentyl group, Fluorination of 2,2,3,3,4,4,5,5,5-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group, heptyl group, perfluoroheptyl group, octyl group and perfluorooctyl group Alkyl group, cyclopropylmethyl group, cyclopropyl group, cyclobutylmethyl group, cyclopentyl group, cyclohexyl group, Fluorocyclohexyl group, adamantyl group, adamantylmethyl group, adamantyl dimethyl group, norbornyl group, norbornylmethyl group, perfluoro adamantyl group, a perfluoroalkyl adamantylmethyl group and the like are preferable.

In the formula (a4-3), L ⁵ is preferably an ethylene group.
Divalent saturated hydrocarbon group of A ^f13 is preferably a group containing a divalent alicyclic hydrocarbon group having a divalent chain hydrocarbon group and 3 to 12 carbon atoms having 1 to 6 carbon atoms, carbon atoms 2-3 divalent chain hydrocarbon groups are more preferred.
The saturated hydrocarbon group for A ^f14 is preferably a group containing a chain hydrocarbon group having 3 to 12 carbon atoms and an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and is preferably a chain hydrocarbon group having 3 to 10 carbon atoms. And a group containing an alicyclic hydrocarbon group having 3 to 10 carbon atoms is more preferable. Among them, ^Af14 is preferably a group containing an alicyclic hydrocarbon group having 3 to 12 carbon atoms, and more preferably a cyclopropylmethyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group.

Examples of the structural unit represented by the formula (a4-3) include structural units represented by the formulas (a4-1′-1) to (a4-1′-11). A structural unit in which the methyl group corresponding to R ^f7 in the structural unit (a4-3) is replaced with a hydrogen atom is also exemplified as the structural unit represented by the formula (a4-3).

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

^As the saturated hydrocarbon group for R ^f22 , the same as the saturated hydrocarbon group for R ^a42 can be mentioned. R ^f22 is preferably an alkyl group having 1 to 10 carbon atoms having a fluorine atom or an alicyclic hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom, more preferably an alkyl group having 1 to 10 carbon atoms having a fluorine atom. Preferably, an alkyl group having 1 to 6 carbon atoms having a fluorine atom is more preferable.
In the formula (a4-4), A ^f21 is preferably — (CH ₂ ) _j1 —, more preferably an ethylene group or a methylene group, and further preferably a methylene group.

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

  When the resin (A) has the structural unit (a4), its content is preferably 1 to 20 mol%, more preferably 2 to 15 mol%, and more preferably 3 to 15 mol%, based on all structural units of the resin (A). -10 mol% is more preferred.

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

The alicyclic hydrocarbon group for R ⁵² may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group. Examples of the polycyclic alicyclic hydrocarbon group include an adamantyl group and a norbornyl group.
Aliphatic hydrocarbon groups having 1 to 8 carbon atoms include, for example, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl and octyl. An alkyl group such as -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, more preferably an adamantyl group, a norbornyl group or a cyclohexyl group.
Examples of the divalent saturated hydrocarbon group for L ⁵⁵ include a divalent chain saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, and preferably a divalent chain saturated hydrocarbon group. .
Examples of the divalent chain 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 a cycloalkanediyl group such as a cyclopentanediyl group and a cyclohexanediyl group. Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include an adamantanediyl group and a norbornanediyl group.

-CH ₂ contained in the divalent saturated hydrocarbon group represented by L ⁵⁵ - is, the group replaced by -O- or -CO-, for example, by the formula (L1-1) ~ formula (L1-4) The groups represented are mentioned. In the following formulas, * and ** each represent a bond, and * represents a bond to an oxygen atom.
In the formula (L1-1),
X ^x1 represents * -O-CO- or * -CO-O- (* represents a bond to L ^x1 ).
L ^x1 represents a divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms.
L ^x2 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
However, the total carbon number of L ^x1 and L ^x2 is 16 or less.
In the 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 the 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 the formula (L1-4),
L ^x8 and L ^{x9 each} represent a single bond or a divalent saturated aliphatic hydrocarbon group having 1 to 12 carbon atoms.
W ^x1 represents a divalent alicyclic saturated hydrocarbon group having 3 to 15 carbon atoms.
However, the total carbon number of L ^x8 , L ^x9 and W ^x1 is 15 or less.

L ^x1 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, more preferably a methylene group or an ethylene group.
L ^x2 is preferably a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms, and more preferably a single bond.
L ^x3 is preferably a divalent aliphatic saturated hydrocarbon group having 1 to 8 carbon atoms.
^Lx4 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.
^Lx6 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.

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

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

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

Examples of the group represented by the formula (L1-4) include the following divalent groups.
L ⁵⁵ is preferably a single bond or a group represented by the formula (L1-1).

The structural unit (a5-1), a methyl group corresponding to R ⁵¹ may be mentioned a structural unit replacing a hydrogen atom in the structural units in the structural units and the following structural units shown below (a5-1).

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

<Structural unit (III)>
The resin (A) may further contain a structural unit that decomposes upon exposure to generate an acid (hereinafter, may be referred to as “structural unit (III)”). The structural unit described in JP-A-2006-79235 is mentioned, a structural unit having a sulfonate group or a carboxylate group and an organic cation in a side chain or a structural unit having a sulfonio group and an organic anion in a side chain. Preferably, there is.
The structural unit having a sulfonate group or a carboxylate group and an organic cation in the side chain is preferably a structural unit represented by the formula (III-2-A ′).
[In the formula (III-2-A ′),
X ^III3 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, -CH ₂ contained in the saturated hydrocarbon group - is -O -, - it is replaced in S- or -CO- The hydrogen atom contained in the saturated hydrocarbon group may be replaced by 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.
ZA ⁺ represents an organic cation. ]

Examples of the halogen atom represented by R ^III3 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
As the alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^III3, the alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^a8 The same is mentioned.
The alkanediyl group having 1 to 8 carbon atoms represented by A ^x1, methylene group, ethylene group, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl 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 and the like. No.
Examples of the perfluoroalkyl group having 1 to 6 carbon atoms which may be substituted by ^Ax1 include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, and a perfluorotert-butyl group. -Butyl group, perfluoropentyl group, perfluorohexyl group and the like.
Examples of the divalent saturated hydrocarbon group having 1 to 18 carbon atoms represented by ^XIII3 include a linear or branched alkanediyl group and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group. And 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 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, Divalent monocyclic alicyclic saturated hydrocarbon group such as cycloalkanediyl group such as looctane-1,5-diyl group; norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane- Examples thereof include a divalent polycyclic alicyclic saturated hydrocarbon group such as a 1,5-diyl group and an adamantane-2,6-diyl group.
Examples of the thing in which —CH ₂ — contained in the saturated hydrocarbon group is replaced by —O—, —S— or —CO— include divalent groups represented by formulas (X1) to (X53). No. However, -CH ₂ contained in a saturated hydrocarbon group - is, -O -, - number of carbon atoms before replacing with S- or -CO- is respectively 17 or less. In the following formulas, * and ** represent the binding site, * 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 a carbon number of 1 to 13.
X ⁶ represents a divalent saturated hydrocarbon group having 1 to 14 carbon atoms.
X ⁷ represents a trivalent saturated hydrocarbon group having 1 to 14 carbon atoms.
X ⁸ represents a divalent saturated hydrocarbon group having a carbon number of 1 to 13.

Examples of the organic cation represented by ZA ⁺ include an organic onium cation, for example, an organic sulfonium cation, an organic iodonium cation, an organic ammonium cation, an organic benzothiazolium cation, an organic phosphonium cation, and the like, and an organic sulfonium cation and an organic iodonium cation Are preferable, and an arylsulfonium cation is more preferable.
ZA ⁺ in the formula (III-2-A ′) is the same as the organic cation Z ⁺ in the acid generator (B1) described later.

The structural unit represented by the formula (III-2-A ′) is preferably a structural unit represented by the formula (III-2-A).
[In formula (III-2-A), R ^III3 , X ^III3 and ZA ⁺ represent the same meaning as described above.
z2A represents any integer of 0 to 6.
R ^III2 and R ^III4 each independently represent a hydrogen atom, a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and when z2A is 2 or more, a plurality of R ^III2 and R ^III4 are the same as each other; Or different.
Q ^a and Q ^b are each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms. ]

The ^{R III2,} R III4, ^Q perfluoroalkyl group having 1 to 6 carbon atoms represented by ^a and ^{Q b,} include those similar to the perfluoroalkyl group having 1 to 6 carbon atoms represented by below of ^{Q b1} .

The structural unit represented by the formula (III-2-A) is preferably a structural unit represented by the formula (III-2-A-1).
[In the formula (III-2-A-1),
R ^III2 , R ^III3 , R ^III4 , Q ^a , Q ^b and ZA ⁺ represent the same meaning as described above.
z2A1 represents an integer of any of 0 to 6.
R ^III5 represents a saturated hydrocarbon group having 1 to 12 carbon atoms.
X ^I2 represents a divalent saturated hydrocarbon group of 1 to 11 carbon atoms, -CH ₂ contained in the saturated hydrocarbon group - is -O -, - it is replaced in 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 a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, Examples thereof include a linear or branched alkyl group such as a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group and a dodecyl group.
Examples of the divalent saturated hydrocarbon group represented by X ^I2, are the same as those of the divalent saturated hydrocarbon group represented by X ^III3.

As the structural unit represented by the formula (III-2-1), a structural unit represented by the formula (III-2-A-2) is preferable.
[In formula (III-2-A-2), R ^III3 , R ^III5, and ZA ⁺ 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 (III-2-A ′) include the following structural units and the structural units described in WO2012 / 050015. ZA ⁺ represents an organic cation.

The structural unit having a cation having a sulfonio group in the side chain and an organic anion is preferably a structural unit represented by the formula (III-1-1).
[In the formula (III-1-1),
A ^II1 represents a single bond or a divalent linking group.
R ^II1 represents a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^II2 and R ^II3 each independently represent a hydrocarbon group having 1 to 18 carbon atoms, and R ^II2 and R ^II3 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.
R ^II4 represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
A ^- represents an organic anion. ]
Examples of the divalent aromatic hydrocarbon group having 6 to 18 carbon atoms represented by R ^II1 include a phenylene group and a naphthylene group.
Examples of the hydrocarbon group represented by R ^II2 and R ^II3 include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these.
Examples of the halogen atom represented by R ^II4 include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
As the alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^II4 is an alkyl group having 1 to 6 carbon atoms which may have a halogen atom represented by R ^a8 The same is mentioned.
Examples of the divalent linking group represented by A ^II1, for example, include a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, -CH 2 contained in a saturated hydrocarbon group of the divalent _- is It may be replaced by -O-, -S- or -CO-. Specific examples include the same divalent saturated hydrocarbon groups having 1 to 18 carbon atoms represented by ^XIII3 .

Examples of the structural unit containing a cation in the formula (III-1-1) include the following structural units.

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

Examples of the sulfonylimide anion represented by A ⁻ include the following.

Examples of the sulfonylmethide anion include the following.

Examples of the carboxylate anion include the following.

Examples of the structural unit represented by the formula (III-1-1) include the following structural units.

  When the structural unit (III) is contained in the resin (A), the content of the structural unit (III) is preferably from 1 to 20 mol% based on all structural units of the resin (A). Preferably it is 2 to 15 mol%, more preferably 3 to 10 mol%.

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

  The resin (A) is preferably a resin comprising the structural unit (I), the structural unit (II), the structural unit (a1-1), and the structural unit (a2-A), and the structural unit (I) and the structural unit ( II) a resin composed of a structural unit (a1-2) and a structural unit (a2-A), a structural unit (I), a structural unit (I), a structural unit (a1-1), and a structural unit (a1-2) And a resin comprising a structural unit (a2-A), a structural unit (I), a structural unit (II), a structural unit (a1-1), a structural unit (a1-2), a structural unit (a2-A), and a structure Resin consisting of unit (s), structural unit (I), structural unit (II), structural unit (a1-1), structural unit (a1-2), structural unit (a2-A), and structural unit (III) A resin consisting of the structural unit (I), the structural unit (II), the structural unit (a1-1), and the structural unit (a1-2) A resin comprising the unit (a2-A), the structural unit (s), the structural unit (a4), and / or the structural unit (a5), or the structural unit (I), the structural unit (II), and the structural unit (a1- 1) a resin comprising a structural unit (a1-2), a structural unit (a2-A), and a structural unit (a4), and more preferably a structural unit (I), a structural unit (II), and a structural unit ( a1-1), a resin comprising a structural unit (a1-2) and a structural unit (a2-A), a structural unit (I), a structural unit (II), a structural unit (a1-1) and a structural unit (a1- 2) a resin composed of a structural unit (a2-A) and a structural unit (s), a structural unit (I), a structural unit (II), a structural unit (a1-1), a structural unit (a1-2), and a structure It is a resin comprising a unit (a2-A) and a structural unit (III).

The structural unit (a1) is preferably at least one selected from the group consisting of a structural unit (a1-0) and a structural unit (a1-0X).
The structural unit (s) is preferably at least one selected from the group consisting of the structural unit (a2) and the structural unit (a3). The structural unit (a2) is preferably a structural unit (a2-1). The structural unit (a3) is preferably a structural unit represented by the formula (a3-1), a structural unit represented by the formula (a3-2), a structural unit represented by the formula (a3-3), and a compound represented by the formula (a3-3): at least one selected from the group consisting of the structural units represented by a3-4).

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, a radical polymerization method) using a monomer that leads to these structural units. be able to. The content of each structural unit of the resin (A) can be adjusted by the amount of the monomer used for polymerization.
The weight average molecular weight of the resin (A) is preferably 2,000 or more (more preferably 2,500 or more, more preferably 3,000 or more), 50,000 or less (more preferably 30,000 or less, and further preferably 15,000 or less).
In the present specification, the weight average molecular weight is a value determined by gel permeation chromatography. Gel permeation chromatography can be measured under the analysis conditions described in the examples.

(Resist composition)
The resist composition of the present invention preferably contains a resin (A) and an acid generator known in the resist field (hereinafter sometimes referred to as “acid generator (B)”).
The resist composition of the present invention may further contain a resin other than the resin (A).
The resist composition of the present invention preferably contains a quencher such as a salt that generates an acid having a lower acidity than the acid generated from the acid generator (hereinafter sometimes referred to as “quencher (C)”). And a solvent (hereinafter sometimes referred to as “solvent (E)”).

<Resins other than resin (A)>
The resin other than the resin (A) may be any resin that does not contain the structural unit (I) or the structural unit (a2-A). Examples of such a resin include a resin obtained by removing the structural unit (I) from the resin (A) (hereinafter sometimes referred to as “resin (AY)”), and a structural unit (a2-A) from the resin (A). Excluded resin (hereinafter sometimes referred to as “resin (AZ)”), resin composed only of structural unit (a4) and structural unit (a5) (hereinafter sometimes referred to as resin (X)), and the like.

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

Each of the structural units constituting the resin (X) may be used alone or in combination of two or more, and is produced by a known polymerization method (for example, a radical polymerization method) using a monomer for deriving these structural units. can do. The content of each structural unit of the resin (X) can be adjusted by the amount of the monomer used for polymerization.
The weight average molecular weights of the resin (AY), the resin (AZ) and the resin (X) are each independently preferably 6,000 or more (more preferably 7,000 or more), 80,000 or less (more preferably 60 or more). 2,000 or less). The means for measuring the weight average molecular weight of the resin (AY), the resin (AZ) and the resin (X) is the same as that for the resin (A).
When the resist composition of the present invention contains the resin (AY) and / or the resin (AZ), the total content thereof is usually 1 to 2500 parts by mass (more preferably 100 parts by mass of the resin (A)). Is 10 to 1000 parts by mass).
When the resist composition contains the resin (X), the content is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, based on 100 parts by mass of the resin (A). More preferably, it is 1 to 40 parts by mass, particularly preferably 1 to 30 parts by mass, particularly preferably 1 to 8 parts by mass.

  In the resist composition of the present invention, the resin (A) may be used in combination with a resin other than the resin (A), and when a resin other than the resin (A) is used in combination, a resin containing a structural unit having an acid labile group It is preferable to use a resin containing a structural unit having a fluorine atom and / or a resin (AY), a resin (AZ) and / or a resin (X) in combination.

  The content of the resin (A) in the resist composition is preferably from 80% by mass to 99% by mass, more preferably from 90% to 99% by mass, based on the solid content of the resist composition. When a resin other than the resin (A) is contained, the total content of the resin (A) and the resin other than the resin (A) is from 80% by mass to 99% by mass based on the solid content of the resist composition. It is preferably at most 90% by mass, more preferably 90 to 99% by mass. The solid content of the resist composition and the content of the resin with respect to the solid content can be measured by known analytical means such as liquid chromatography or gas chromatography.

<Acid generator (B)>
The acid generator (B) may be either nonionic or ionic. Examples of the nonionic acid generator include sulfonate esters (eg, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonate), sulfones (eg, disulfone, Ketosulfone, sulfonyldiazomethane) and the like. Onium salts containing onium cations (eg, diazonium salts, phosphonium salts, sulfonium salts, iodonium salts) are typical examples of the ionic acid generator. Examples of the anion of the onium salt include a sulfonic acid anion, a sulfonylimide anion, and a sulfonylmethide anion.
Examples of the acid generator (B) include JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038, and JP-A-63-163452. JP-A-62-153853, JP-A-63-146029, U.S. Pat. No. 3,779,778, U.S. Pat. No. 3,849,137, German Patent No. 3,914,407, European Patent No. 126,712, etc. The compounds capable of generating an acid by the radiation described in (1) can be used. Further, a compound produced by a known method may be used. The acid generator (B) may be used in combination of two or more.

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

^Examples of the perfluoroalkyl group represented by Q ^b1 and Q ^b2 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 And perfluorohexyl groups.
Q ^b1 and Q ^b2 are each independently preferably a fluorine atom or a trifluoromethyl group, and more preferably both are fluorine atoms.
Examples of the divalent saturated hydrocarbon group for L ^b1 include a linear alkanediyl group, a branched alkanediyl group, and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group. It may be a group formed by combining two or more of the groups.
Specifically, methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1 , 7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group Linear groups such as tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group and heptadecane-1,17-diyl group 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 a cyclobutane-1,3-diyl group, a cyclopentane-1,3-diyl group, a cyclohexane-1,4-diyl group, a cyclooctane-1,5-diyl group; Divalent 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 and the like And the like.
Examples of the group in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ^b1 is replaced by —O— or —CO— include, for example, formulas (b1-1) to (b1-3) And a group represented by any of the following: Note that, in the groups represented by the formulas (b1-1) to (b1-3) and the groups represented by the formulas (b1-4) to (b1-11), which are specific examples, * and * * Represents a binding site, and * represents a bond to -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 a 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 a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group; —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
^However, the total number of carbon atoms of ^{L b2} and ^{L b3} is 22 or less.
In the formula (b1-2),
L ^b4 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a 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 a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group; —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
^However, the total number of carbon atoms of ^{L b4} and ^{L b5} is 22 or less.
In the formula (b1-3),
L ^b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and a 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 a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group; —CH ₂ — contained in the hydrocarbon group may be replaced by —O— or —CO—.
^However, the total number of carbon atoms of ^{L b6} and ^{L b7} is 23 or less. ]
In the groups represented by the formulas (b1-1) to (b1-3), when —CH ₂ — contained in the saturated hydrocarbon group is replaced by —O— or —CO—, the carbon before replacement is Let the number be the carbon number of the saturated hydrocarbon group.
Examples of the divalent saturated hydrocarbon group include the same as the divalent saturated hydrocarbon group for ^Lb1 .

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 a 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 a 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 a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group; —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—.
Examples of the group in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ^b1 is replaced by —O— or —CO— include those represented by formula (b1-1) or formula (b1-3). Are preferred.

Examples of the group represented by the formula (b1-1) include groups represented by the formulas (b1-4) to (b1-8).
[In the formula (b1-4),
L ^b8 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
In the formula (b1-5),
L ^b9 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—.
L ^b10 represents a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group .
However, the total carbon number of ^Lb9 and ^Lb10 is 20 or less.
In the formula (b1-6),
L ^b11 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b12 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group .
^However, the total number of carbon atoms of ^{L b11} and ^{L b12} is 21 or less.
In the formula (b1-7),
^Lb13 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.
L ^b14 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and -CH _2- contained in the divalent saturated hydrocarbon group is replaced by -O- or -CO-. Is also good.
L ^b15 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and a hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group .
^However, the total number of carbon atoms of L b13 ^{~L b15} is 19 or less.
In the formula (b1-8),
L ^b16 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—.
^Lb17 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b18 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group .
^However, the total number of carbon atoms of L b16 ^{~L b18} is 19 or less. ]

^Lb8 is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.
^Lb9 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
^Lb10 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
^Lb11 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
^Lb12 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
^Lb13 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b14 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
^Lb15 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
^Lb16 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
^Lb17 is preferably a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b18 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.

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

Examples of the group represented by the formula (b1-4) include the following.

Examples of the group represented by the formula (b1-5) include the following.

Examples of the group represented by the formula (b1-6) include the following.

Examples of the group represented by the formula (b1-7) include the following.

Examples of the group represented by the formula (b1-8) include the following.

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

Examples of the group represented by the formula (b1-9) include the following.

Examples of the group represented by the formula (b1-10) include the following.

Examples of the group represented by the formula (b1-11) include the following.

Examples of the alicyclic hydrocarbon group represented by Y include groups represented by formulas (Y1) to (Y11) and formulas (Y36) to (Y38).
When —CH ₂ — contained in the alicyclic hydrocarbon group represented by Y is replaced by —O—, —S (O) ₂ — or —CO—, the number may be one or two or more. Good. Examples of such a group include groups represented by Formulas (Y12) to (Y35) and Formulas (Y39) to (Y41).
As the alicyclic hydrocarbon group represented by Y, preferably, formulas (Y1) to (Y20), formula (Y26), formula (Y27), formula (Y30), formula (Y31), and formula (Y39) To a group represented by any one of formulas (Y41) to (Y41), more preferably a formula (Y11), a formula (Y15), a formula (Y16), a formula (Y20), a formula (Y26), a formula (Y27), or a formula A group represented by formula (Y30), formula (Y31), formula (Y39) or formula (Y40), and more preferably formula (Y11), formula (Y15), formula (Y20), formula (Y26), A group represented by formula (Y27), formula (Y30), formula (Y31), formula (Y39) or formula (Y40).
When the alicyclic hydrocarbon group represented by Y is a spiro ring represented by formulas (Y28) to (Y35), (Y39) to (Y40), an alkanediyl group between two oxygen atoms Preferably has one or more fluorine atoms. Further, among the alkanediyl groups contained in the ketal structure, it is preferable that the methylene group adjacent to the oxygen atom is not substituted with a fluorine atom.

Examples of the substituent of 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,-( ^{_{CH 2) ja -CO-O-}} R b1 group or _{- (CH 2) ja -O-} CO-R b1 group ^{(wherein, R b1} represents an alkyl group having 1 to 16 carbon atoms, 3 to 16 carbon atoms alicyclic hydrocarbon group, an aromatic hydrocarbon group or a group composed of a combination of these having 6 to 18 carbon atoms, -CH 2 contained in the alkyl group and alicyclic hydrocarbon group _- is, -O- , -SO ₂ -or -CO-, and the hydrogen atom contained in the alkyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group may be replaced by a hydroxy group or a fluorine atom. Ja represents an integer of any of 0 to 4) And the like.
Examples of the substituent of 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 by 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 alkylcarbonyl group having 2 to 4 carbon atoms, a glycidyloxy group,-( ^{_{CH 2) ja -CO-O-}} R b1 group or _{- (CH 2) ja -O-} CO-R b1 group ^{(wherein, R b1} represents an alkyl group having 1 to 16 carbon atoms, 3 to 16 carbon atoms alicyclic hydrocarbon group, an aromatic hydrocarbon group or a group composed of a combination of these having 6 to 18 carbon atoms, -CH 2 contained in the alkyl group and alicyclic hydrocarbon group _- is, -O- , -SO ₂ - may be replaced or -CO-, The hydrogen atom contained in the alkyl group, the alicyclic hydrocarbon group and the aromatic hydrocarbon group may be replaced by a hydroxy group or a fluorine atom, and ja represents any integer of 0 to 4. And the like.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a norbornyl group, an adamantyl group, and the like.
Examples of the aromatic hydrocarbon group include an aryl group such as a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, and a phenanthryl group. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group. The aromatic hydrocarbon group having a chain hydrocarbon group (tolyl group, xylyl group, cumenyl group, mesityl group) Group, p-ethylphenyl group, p-tert-butylphenyl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.) and an aromatic hydrocarbon group having an alicyclic hydrocarbon group ( p-cyclohexylphenyl group, p-adamantylphenyl group, etc.).
Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, 2-ethylhexyl, octyl, and nonyl. Group, decyl group, undecyl group, dodecyl group and the like.
Examples of the alkyl group substituted with a hydroxy group include a hydroxyalkyl group such as a hydroxymethyl group and a hydroxyethyl group.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group, and a dodecyloxy group.
Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group and a naphthylethyl group.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group, and a butyryl group.

Examples of Y include the following.

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

  As the anion in the acid generator (B1), an anion represented by the formula (B1-A-1) to the formula (B1-A-55) [hereinafter, “anion (B1-A-1)” according to the formula number And so on. Are preferred, and the formulas (B1-A-1) to (B1-A-4), the formula (B1-A-9), the formula (B1-A-10), and the formulas (B1-A-24) to (B1-A-33), Formula (B1-A-36) to Formula (B1-A-40), or Formula (B1-A-47) to Formula (B1-A-55). Anions are more preferred.

Here, R ^{i2 to} R ⁱ⁷ each independently represent, 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. And more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group. ^LA4 is a single bond or an alkanediyl group having 1 to 4 carbon atoms.
Q ^b1 and Q ^b2 represent the same meaning as described above.
Specific examples of the acid generator (B1) include anions described in JP-A-2010-204646.

Preferred anions in the acid generator (B1) include anions represented by the formulas (B1a-1) to (B1a-34).

  Among them, the formulas (B1a-1) to (B1a-3) and the formulas (B1a-7) to (B1a-16), the formula (B1a-18), the formula (B1a-19), and the formula (B1a-22) ) To anion represented by any one of formulas (B1a-30).

Examples of the organic cation for Z ⁺ include an organic onium cation, an organic sulfonium cation, an organic iodonium cation, an organic ammonium cation, a benzothiazolium cation, and an organic phosphonium cation. Among these, an organic sulfonium cation and an organic iodonium cation are preferable, and an aryl sulfonium cation is more preferable. Specifically, a cation represented by any of formulas (b2-1) to (b2-4) (hereinafter, may be referred to as “cation (b2-1)” or the like depending on the formula number). No.

In the formulas (b2-1) to (b2-4),
R ^{b4 to} R ^b6 each independently represent a chain hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 36 carbon atoms; The hydrogen atom contained in the chain hydrocarbon group is a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms. A hydrogen atom contained in the alicyclic hydrocarbon group which may be substituted is a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms or a glycidyloxy group. The hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group or an alkoxy group having 1 to 12 carbon atoms.
R ^b4 and R ^b5 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, and -CH _2- contained in the ring is -O-, -S- or It may be replaced by -CO-.
R ^b7 and R ^b8 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0 to 5;
When m2 is 2 or more, a plurality of R ^b7 may be the same or different, and when n2 is 2 or more, a plurality of R ^b8 may be the same or different.
R ^b9 and R ^b10 each independently represent a chain hydrocarbon group having 1 to 36 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms.
R ^b9 and R ^b10 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, and -CH _2- contained in the ring is -O-, -S- or It may be replaced by -CO-.
R ^b11 represents a hydrogen atom, a chain hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^b12 represents a chain hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and is included in the chain hydrocarbon. May be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group may be an alkoxy group having 1 to 12 carbon atoms or a carbon atom having 1 to 12 carbon atoms. It may be substituted with 12 alkylcarbonyloxy groups.
R ^b11 and R ^b12 may be bonded to each other to form a ring including —CH—CO— to which they are bonded, and —CH ₂ — contained in the ring includes —O— and —S -Or -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 a sulfur atom or an oxygen atom.
o2, p2, s2, and t2 each independently represent any integer of 0 to 5.
q2 and r2 each independently represent any integer of 0 to 4.
u2 represents 0 or 1.
When o2 is 2 or more, a plurality of R ^b13 are the same or different. When p2 is 2 or more, a plurality of R ^b14 are the same or different. When q2 is 2 or more, a plurality of R ^b15 are the same or different. , When r2 is 2 or more, a plurality of R ^b16 are the same or different; when s2 is 2 or more, a plurality of R ^b17 are the same or different; when t2 is 2 or more, a plurality of R ^b18 are the same or different. different.
The aliphatic hydrocarbon group represents a chain hydrocarbon group and an alicyclic hydrocarbon group.
Examples of the chain hydrocarbon group include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl and 2-ethylhexyl alkyl groups. No.
In particular, the chain 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 cyclohexyl group. Cycloalkyl groups such as a heptyl group, a cyclooctyl group and a cyclodecyl group are exemplified. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group, and the following groups.
In particular, the alicyclic hydrocarbon group of R ^{b9 to} R ^b12 preferably has 3 to 18 carbon atoms, more preferably 4 to 12 carbon atoms.
Examples of the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a 2-methyladamantan-2-yl group, and a 2-ethyladamantan-2-yl group. , 2-isopropyladamantan-2-yl group, methylnorbornyl group, isobornyl group and the like. In the alicyclic hydrocarbon group in which a hydrogen atom has been substituted with an aliphatic hydrocarbon group, the total carbon number of the alicyclic hydrocarbon group and the aliphatic hydrocarbon group is preferably 20 or less.
Examples of the aromatic hydrocarbon group include aryl groups such as a phenyl group, a biphenyl group, a naphthyl group, and a phenanthryl group. The aromatic hydrocarbon group may have a chain hydrocarbon group or an alicyclic hydrocarbon group. The aromatic hydrocarbon group having a chain hydrocarbon group (tolyl group, xylyl group, cumenyl group, mesityl group) Group, p-ethylphenyl group, p-tert-butylphenyl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc.) and an aromatic hydrocarbon group having an alicyclic hydrocarbon group ( p-cyclohexylphenyl group, p-adamantylphenyl group, etc.).
When the aromatic hydrocarbon group contains a chain hydrocarbon group or an alicyclic hydrocarbon group, the chain hydrocarbon group has 1 to 18 carbon atoms and the alicyclic hydrocarbon group has 3 to 18 carbon atoms. Groups are preferred.
Examples of the aromatic hydrocarbon group in which a hydrogen atom is substituted with an alkoxy group include a p-methoxyphenyl group.
Examples of the chain hydrocarbon group in which a hydrogen atom is substituted with an aromatic hydrocarbon group include aralkyl groups such as benzyl group, phenethyl group, phenylpropyl group, trityl group, naphthylmethyl group, and naphthylethyl group.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group, and a dodecyloxy group.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group and a butyryl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, a propylcarbonyloxy group, an isopropylcarbonyloxy group, a butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, and a pentylcarbonyloxy group Hexylcarbonyloxy group, octylcarbonyloxy group and 2-ethylhexylcarbonyloxy group.
R ^b4 and R ^b5 are bonded to each other to form a ring together with the sulfur atom to which they are bonded, and may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated, and unsaturated. May be a ring of The ring includes a ring having 3 to 18 carbon atoms, and is preferably a ring having 4 to 18 carbon atoms. The ring containing a sulfur atom may be a 3- to 12-membered ring, preferably a 3- to 7-membered ring, for example, the following rings. * Represents a binding site.
The ring formed by R ^b9 and R ^b10 together may be any of a monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated ring. The ring may be a 3- to 12-membered ring, preferably a 3- to 7-membered ring. For example, a thiolan-1-ium ring (tetrahydrothiophenium ring), a thiane-1-ium ring, a 1,4-oxathian-4-ium ring and the like can be mentioned.
The ring formed by R ^b11 and R ^b12 together may be any of a monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated ring. The ring may be a 3- to 12-membered ring, preferably a 3- to 7-membered ring. Oxocycloheptane ring, oxocyclohexane ring, oxonorbornane ring, oxoadamantane ring and the like.

Among cations (b2-1) to cations (b2-4), cations (b2-1) are preferred.
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 (B) is a combination of the above-mentioned anion and the above-mentioned organic cation, and these can be arbitrarily combined. As the acid generator (B), preferably, the formulas (B1a-1) to (B1a-3) and the formulas (B1a-7) to (B1a-16), the formulas (B1a-18), and the formulas (B1a-) 19), and a combination of an anion represented by any one of formulas (B1a-22) to (B1a-34) with a cation (b2-1) or a cation (b2-3).

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

  In the resist composition of the present invention, the content of the acid generator is preferably from 1 part by mass to 40 parts by mass, more preferably from 3 parts by mass to 35 parts by mass, per 100 parts by mass of the resin (A). And more preferably 10 parts by mass or more and 35 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) in the resist composition is usually from 90% by mass to 99.9% by mass, preferably from 92% by mass to 99% by mass, more preferably from 94% by mass to 99% by mass. % Or less. The content of the solvent (E) can be measured by a known analytical means such as liquid chromatography or gas chromatography.
Examples of the solvent (E) include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate; glycol ethers such as propylene glycol monomethyl ether; ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate; Esters; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; One kind of the solvent (E) may be used alone, or two or more kinds may be used.

<Quencher (C)>
Examples of the quencher (C) include a salt that generates an acid having a lower acidity than the acid generated from the acid generator (B), and a basic nitrogen-containing organic compound. The content of the quencher (C) is preferably about 0.01 to 5% by mass, and more preferably about 0.01 to 3% by mass, based on the solid content of the resist composition.

<Salt that generates an acid whose acidity is weaker than the acid generated from the acid generator>
The acidity of a salt that generates an acid having a lower acidity than the acid generated from the acid generator (B) is represented by an acid dissociation constant (pKa). The salt that generates an acid having a lower acidity than the acid generated from the acid generator (B) is a salt whose acid dissociation constant of the acid generated from the salt is usually −3 <pKa, preferably −1 <pKa. It is a salt with pKa <7, and more preferably a salt with 0 <pKa <5.
Examples of the salt that generates an acid having a lower acidity than the acid generated from the acid generator (B) include a salt represented by the following formula and a salt represented by the formula (D) described in JP-A-2015-147926. (Hereinafter sometimes referred to as “weak acid inner salt (D)”), JP-A-2012-229206, JP-A-2012-6908, JP-A-2012-72109, and JP-A-2011-39502. And the salts described in JP-A-2011-191745. The salt that generates an acid having a lower acidity than the acid generated from the acid generator (B) is preferably a weak acid inner salt (D).

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

Examples of the basic nitrogen-containing organic compound include amines and ammonium salts. Amines include aliphatic amines and aromatic amines. Aliphatic amines include primary, secondary and tertiary amines.
Examples of the amine include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N-dimethylaniline, diphenylamine, hexylamine, Heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, trihexylamine Heptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, Rudicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyl Didecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, 2,2'-methylenebisaniline, imidazole, 4-methyli Dazole, 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, Examples include 4′-dipyridyl disulfide, 2,2′-dipyridylamine, 2,2′-dipicolylamine, bipyridine and the like, preferably aromatic amines such as diisopropylaniline, more preferably 2,6-diisopropyl Aniline is mentioned.
Examples of the ammonium salt include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, and 3- (trifluoromethyl) phenyltrimethyl. Ammonium hydroxide, tetra-n-butylammonium salicylate, choline and the like.

<Other ingredients>
The resist composition of the present invention may contain components other than the above-described 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, for example, a sensitizer, a dissolution inhibitor, a surfactant, a stabilizer, a dye, and the like can be used.

<Preparation of resist composition>
The resist composition of the present invention comprises a resin (A) of the present invention, an acid generator (B), a salt that generates an acid having a lower acidity than the acid generated from the acid generator, and, if necessary, a resin. It can be prepared by mixing (A2), resin (X), quencher (C), solvent (E) and other components (F). The mixing order is arbitrary and is not particularly limited. An appropriate temperature can be selected from 10 to 40 ° C. depending on the type of the resin and the like and the solubility of the resin and the like in the solvent (E). 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 perform filtration using a filter having a pore size of about 0.003 to 0.2 μm.

<Resist pattern manufacturing method>
The method for producing a resist pattern according to the present invention includes:
(1) a step of applying the resist composition of the present invention on a substrate,
(2) drying the composition after application to form a composition layer;
(3) a step of exposing the composition layer,
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.
The application of the resist composition onto the substrate can be performed 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 application, the solvent is removed to form a composition layer. Drying is performed, for example, by evaporating the solvent using a heating device such as a hot plate (so-called prebaking), or using a decompression device. The heating temperature is preferably from 50 to 200 ° C., and the heating time is preferably from 10 to 180 seconds. The pressure at the time of 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. The exposure light source, which emits laser light in a UV-region such as a KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), solid-state laser source (YAG or semiconductor laser Etc.), use various types of laser light, such as one that emits harmonic laser light in the far ultraviolet or vacuum ultraviolet region by converting the wavelength of the laser light from the above, and one that irradiates an electron beam or ultra-ultraviolet light (EUV). Can be. In the present specification, irradiating these radiations may be collectively referred to as “exposure”. At the time of exposure, the exposure is usually performed through a mask corresponding to the required pattern. When the exposure light source is an electron beam, exposure may be performed by direct drawing without using a mask.
The composition layer after the exposure is subjected to a heat treatment (so-called post-exposure bake) in order to promote a deprotection reaction at the acid labile group. The heating temperature is usually about 50 to 200C, preferably about 70 to 150C.
The heated composition layer is usually developed using a developing solution using a developing device. Examples of the developing method include a dip method, a paddle method, a spray method, a dynamic dispense method, and the like. The development temperature is preferably, for example, 5 to 60 ° C., and the development time is, for example, preferably 5 to 300 seconds. By selecting the type of the developer as follows, a positive resist pattern or a negative resist pattern can be produced.
When producing a positive resist pattern from the resist composition of the present invention, an alkaline developer is used as a developer. The alkaline developer may be any of various alkaline aqueous solutions used in this field. For example, an aqueous solution of tetramethylammonium hydroxide or (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as choline) may, for example, be mentioned. The alkali developer may contain a surfactant.
After the development, it is preferable to wash the resist pattern with ultrapure water, and then remove water remaining on the substrate and the pattern.
When a negative resist pattern is produced from the resist composition of the present invention, a developer containing an organic solvent (hereinafter sometimes referred to as “organic developer”) is used as a developer.
Examples of the organic solvent contained in the organic developer include ketone solvents such as 2-hexanone and 2-heptanone; glycol ether ester solvents such as propylene glycol monomethyl ether acetate; ester solvents such as butyl acetate; glycols such as propylene glycol monomethyl ether. Ether solvents; amide solvents such as N, N-dimethylacetamide; and aromatic hydrocarbon solvents such as anisole.
The content of the organic solvent in the organic developer is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and further preferably substantially only the organic solvent.
Among them, as the organic developer, a developer containing butyl acetate and / or 2-heptanone is preferable. The total content of butyl acetate and 2-heptanone in the organic developer is preferably from 50% by mass to 100% by mass, more preferably from 90% by mass to 100% by mass, and substantially butyl acetate and / or 2% by mass. More preferably it is only heptanone.
The organic developer may contain a surfactant. Further, 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 type different from the organic developer.
It is preferable to wash the developed resist pattern with a rinse solution. The rinsing solution 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 is preferably an alcohol solvent or an ester solvent.
After the cleaning, it is preferable to remove the rinse liquid remaining on the substrate and the pattern.

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

The present invention will be described more specifically with reference to examples. In the examples, "%" and "part" representing the content or the use amount 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 (Tosoh Corporation)
Eluent: tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)
The structure of the compound was confirmed by measuring a molecular ion peak using mass spectrometry (LC: 1100, manufactured by Agilent, MASS: LC / MSD, manufactured by Agilent). In the following examples, the value of this molecular ion peak is indicated by “MASS”.

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

Example 1 [Synthesis of resin A1]
Monomers (a1-4-2), monomer (a1-1-3), monomer (a1-2-6), monomer (a3-1-1), monomer (I-1) and monomer (II- 1) and the molar ratio [monomer (a1-4-2): monomer (a1-1-3): monomer (a1-2-6): monomer (a3-1-1): monomer (I-1) ): Monomer (II-1)] was mixed at a ratio of 34: 26: 20: 3: 10: 7, and further added to the monomer mixture in an amount of 1.5 to the total mass of all monomers. Methyl isobutyl ketone in a mass ratio was mixed. To the obtained mixture, azobisisobutyronitrile as an initiator was added in an amount of 7 mol% based on the total number of moles of all monomers, and the mixture was heated at 85 ° C. for about 5 hours to perform polymerization. Was. Thereafter, an aqueous solution of p-toluenesulfonic acid was added, and the mixture was stirred for 6 hours and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate a resin, which was filtered and collected to obtain a resin A1 (copolymer) having a weight average molecular weight of about 5.8 × 10 ³ in a yield of 63. %. This resin A1 has the following structural units.

Example 2 [Synthesis of Resin A2]
As the monomer, a monomer (a1-4-2), a monomer (a1-1-3), a monomer (a1-2-6), a monomer (I-1) and a monomer (II-1) were used, and the molar ratio thereof was [ Monomer (a1-4-2): monomer (a1-1-3): monomer (a1-2-6): monomer (I-1): monomer (II-1)] is 34: 26: 23: 10. : 7, and further, 1.5% by mass of methyl isobutyl ketone was added to this monomer mixture with respect to the total mass of all the monomers. To the obtained mixture, azobisisobutyronitrile as an initiator was added in an amount of 7 mol% based on the total number of moles of all monomers, and the mixture was heated at 85 ° C. for about 5 hours to perform polymerization. Was. Thereafter, an aqueous solution of p-toluenesulfonic acid was added, and the mixture was stirred for 6 hours and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate a resin, and the resin was filtered and collected to obtain a resin A2 (copolymer) having a weight average molecular weight of about 5.7 × 10 ³ in a yield of 60. %. This resin A2 has the following structural units.

Example 3 [Synthesis of Resin A3]
Monomers (a1-4-2), monomer (a1-1-1), monomer (a1-2-6), monomer (I-1) and monomer (II-1) were used as monomers, and the molar ratio thereof was [ Monomer (a1-4-2): monomer (a1-1-1): monomer (a1-2-6): monomer (I-1): monomer (II-1)] is 34: 20: 30: 9. : 7, and further, 1.5% by mass of methyl isobutyl ketone was added to this monomer mixture with respect to the total mass of all the monomers. To the obtained mixture, azobisisobutyronitrile as an initiator was added in an amount of 7 mol% based on the total number of moles of all monomers, and the mixture was heated at 85 ° C. for about 5 hours to perform polymerization. Was. Thereafter, an aqueous solution of p-toluenesulfonic acid was added, and the mixture was stirred for 6 hours and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate a resin, which was filtered and collected to obtain a resin A3 (copolymer) having a weight average molecular weight of about 5.8 × 10 ³ in a yield of 78. %. This resin A3 has the following structural units.

Example 4 [Synthesis of Resin A4]
Monomers (a1-4-2), monomer (a1-1-2), monomer (a1-2-6), monomer (III-2-A1), monomer (I-1) and monomer (II- 1) and the molar ratio [monomer (a1-4-2): monomer (a1-1-2): monomer (a1-2-6): monomer (III-2-A1): monomer (I-1) ): Monomer (II-1)] is mixed so as to have a ratio of 30: 30: 20: 5: 8: 7. Methyl isobutyl ketone in a mass ratio was mixed. To the obtained mixture, azobisisobutyronitrile as an initiator was added in an amount of 7 mol% based on the total number of moles of all monomers, and the mixture was heated at 85 ° C. for about 5 hours to perform polymerization. Was. Thereafter, an aqueous solution of p-toluenesulfonic acid was added, and the mixture was stirred for 6 hours and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate a resin, and the resin was filtered and collected to obtain a resin A4 (copolymer) having a weight average molecular weight of about 6.0 × 10 ³ in a yield of 70. %. This resin A4 has the following structural units.

Example 5 [Synthesis of Resin A5]
Monomers (a1-4-2), monomer (a1-1-3), monomer (a1-2-2), monomer (a2-1-1), monomer (a3-1-1), monomer ( I-1) and the monomer (II-1), and the molar ratio [monomer (a1-4-2): monomer (a1-1-3): monomer (a1-2-2): monomer (a2-1) -1): Monomer (a3-1-1): Monomer (I-1): Monomer (II-1)] are mixed at a ratio of 34: 28: 14: 3: 3: 10: 8. Further, to this monomer mixture, methyl isobutyl ketone was mixed at 1.5 times the mass of the total mass of all the monomers. To the resulting mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers, and these were added to the mixture at 73%. Heated at ℃ C for about 5 hours. Thereafter, the polymerization reaction solution was cooled to 23 ° C., an aqueous solution of p-toluenesulfonic acid was added, and the mixture was stirred for 3 hours and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate a resin, which was filtered and collected to obtain a resin A5 having a weight average molecular weight of about 5.9 × 10 ³ in a yield of 58%. This resin A5 has the following structural units.

Example 6 [Synthesis of Resin A6]
Monomers (a1-4-2), monomer (a1-1-3), monomer (a1-2-6), monomer (a2-1-3), monomer (a3-4-2), monomer (a I-1) and the monomer (II-1), and the molar ratio [monomer (a1-4-2): monomer (a1-1-3): monomer (a1-2-6): monomer (a2-1) -3): Monomer (a3-4-2): Monomer (I-1): Monomer (II-1)] are mixed at a ratio of 32: 18: 20: 3: 10: 10: 7. Further, to this monomer mixture, methyl isobutyl ketone was mixed at 1.5 times the mass of the total mass of all the monomers. To the resulting mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers, and these were added to the mixture at 73%. Heated at ℃ C for about 5 hours. Thereafter, the polymerization reaction solution was cooled to 23 ° C., an aqueous solution of p-toluenesulfonic acid was added, and the mixture was stirred for 3 hours and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate a resin, which was filtered and collected to obtain a resin A6 having a weight average molecular weight of about 5.9 × 10 ³ in a yield of 58%. This resin A6 has the following structural units.

Example 7 [Synthesis of Resin A7]
Monomers (a1-4-2), monomer (a1-1-3), monomer (a1-2-6), monomer (a3-1-1), monomer (I-3) and monomer (II- 1) and the molar ratio [monomer (a1-4-2): monomer (a1-1-3): monomer (a1-2-6): monomer (a3-1-1): monomer (I-3) ): Monomer (II-1)] was mixed at a ratio of 34: 26: 20: 3: 10: 7, and further added to the monomer mixture in an amount of 1.5 to the total mass of all monomers. Methyl isobutyl ketone in a mass ratio was mixed. To the obtained mixture, azobisisobutyronitrile as an initiator was added in an amount of 7 mol% based on the total number of moles of all monomers, and the mixture was heated at 85 ° C. for about 5 hours to perform polymerization. Was. Thereafter, an aqueous solution of p-toluenesulfonic acid was added, and the mixture was stirred for 6 hours and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate a resin, and the resin was filtered and collected to obtain a resin A7 (copolymer) having a weight average molecular weight of about 5.5 × 10 ³ in a yield of 56. %. This resin A7 has the following structural units.

Example 8 [Synthesis of Resin A8]
Monomers (a1-4-2), monomer (a1-1-3), monomer (a1-2-6), monomer (a3-1-1), monomer (I-9) and monomer (II- 1) and the molar ratio [monomer (a1-4-2): monomer (a1-1-3): monomer (a1-2-6): monomer (a3-1-1): monomer (I-9) ): Monomer (II-1)] was mixed at a ratio of 34: 26: 20: 3: 10: 7, and further added to the monomer mixture in an amount of 1.5 to the total mass of all monomers. Methyl isobutyl ketone in a mass ratio was mixed. To the obtained mixture, azobisisobutyronitrile as an initiator was added in an amount of 7 mol% based on the total number of moles of all monomers, and the mixture was heated at 85 ° C. for about 5 hours to perform polymerization. Was. Thereafter, an aqueous solution of p-toluenesulfonic acid was added, and the mixture was stirred for 6 hours and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate a resin, and the resin was filtered and collected to obtain a resin A8 (copolymer) having a weight average molecular weight of about 5.4 × 10 ³ in a yield of 62. %. This resin A8 has the following structural units.

Example 9 [Synthesis of Resin A9]
Monomers (a1-4-2), monomer (a1-1-3), monomer (a1-2-6), monomer (a3-1-1), monomer (I-11) and monomer (II- 1) and the molar ratio [monomer (a1-4-2): monomer (a1-1-3): monomer (a1-2-6): monomer (a3-1-1): monomer (I-11) ): Monomer (II-1)] was mixed at a ratio of 34: 26: 20: 3: 10: 7, and further added to the monomer mixture in an amount of 1.5 to the total mass of all monomers. Methyl isobutyl ketone in a mass ratio was mixed. To the obtained mixture, azobisisobutyronitrile as an initiator was added in an amount of 7 mol% based on the total number of moles of all monomers, and the mixture was heated at 85 ° C. for about 5 hours to perform polymerization. Was. Thereafter, an aqueous solution of p-toluenesulfonic acid was added, and the mixture was stirred for 6 hours and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate a resin, and the resin was filtered and collected to obtain a resin A9 (copolymer) having a weight average molecular weight of about 5.2 × 10 ³ in a yield of 58. %. This resin A9 has the following structural units.

Example 10 [Synthesis of Resin A10]
Monomers (a1-4-2), monomer (a1-1-3), monomer (a1-2-6), monomer (a2-1-3), monomer (a3-4-2), monomer (a I-3) and the monomer (II-1), and the molar ratio [monomer (a1-4-2): monomer (a1-1-3): monomer (a1-2-6): monomer (a2-1) -3): Monomer (a3-4-2): Monomer (I-3): Monomer (II-1)] is mixed at a ratio of 32: 18: 20: 3: 10: 10: 7. Further, to this monomer mixture, methyl isobutyl ketone was mixed at 1.5 times the mass of the total mass of all the monomers. To the resulting mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers, and these were added to the mixture at 73%. Heated at ℃ C for about 5 hours. Thereafter, the polymerization reaction solution was cooled to 23 ° C., an aqueous solution of p-toluenesulfonic acid was added, and the mixture was stirred for 3 hours and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate a resin, which was filtered and collected to obtain a resin A10 having a weight average molecular weight of about 5.4 × 10 ³ in a yield of 53%. This resin A10 has the following structural units.

Example 11 [Synthesis of Resin A11]
Monomers (a1-4-2), monomer (a1-1-3), monomer (a1-2-6), monomer (a2-1-3), monomer (a3-4-2), monomer (a I-9) and the monomer (II-1), and the molar ratio [monomer (a1-4-2): monomer (a1-1-3): monomer (a1-2-6): monomer (a2-1) -3): Monomer (a3-4-2): Monomer (I-9): Monomer (II-1)] is mixed at a ratio of 32: 18: 20: 3: 10: 10: 7. Further, to this monomer mixture, methyl isobutyl ketone was mixed at 1.5 times the mass of the total mass of all the monomers. To the resulting mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers, and these were added to the mixture at 73%. Heated at ℃ C for about 5 hours. Thereafter, the polymerization reaction solution was cooled to 23 ° C., an aqueous solution of p-toluenesulfonic acid was added, and the mixture was stirred for 3 hours and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate a resin, which was filtered and collected to obtain a resin A11 having a weight average molecular weight of about 5.6 × 10 ³ in a yield of 62%. This resin A11 has the following structural units.

Example 12 [Synthesis of Resin A12]
Monomers (a1-4-2), monomer (a1-1-3), monomer (a1-2-6), monomer (a2-1-3), monomer (a3-4-2), monomer (a I-11) and the monomer (II-1), and the molar ratio [monomer (a1-4-2): monomer (a1-1-3): monomer (a1-2-6): monomer (a2-1) -3): Monomer (a3-4-2): Monomer (I-11): Monomer (II-1)] is mixed at a ratio of 32: 18: 20: 3: 10: 10: 7. Further, to this monomer mixture, methyl isobutyl ketone was mixed at 1.5 times the mass of the total mass of all the monomers. To the resulting mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers, and these were added to the mixture at 73%. Heated at ℃ C for about 5 hours. Thereafter, the polymerization reaction solution was cooled to 23 ° C., an aqueous solution of p-toluenesulfonic acid was added, and the mixture was stirred for 3 hours and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate a resin, which was filtered and collected to obtain a resin A12 having a weight average molecular weight of about 5.1 × 10 ³ in a yield of 51%. This resin A12 has the following structural units.

Synthesis Example 1 [Synthesis of resin AX1]
A monomer (a1-1-1) and a monomer (I-1) are used as the monomer, and the molar ratio [monomer (a1-1-1): monomer (I-1)] is 31:69. Was mixed in this manner, and further, 1.5% by mass of methyl isobutyl ketone was mixed with the monomer mixture based on the total mass of all the monomers. To the obtained mixture, azobisisobutyronitrile as an initiator was added in an amount of 7 mol% based on the total number of moles of all monomers, and the mixture was heated at 85 ° C. for about 5 hours to perform polymerization. Was. Thereafter, the polymerization solution was poured into a large amount of n-heptane to precipitate a resin, and the resin was filtered and collected to obtain a resin AX1 having a weight average molecular weight of about 5.9 × 10 ³ in a yield of 89%. This resin AX1 has the following structural units.

Synthesis Example 2 [Synthesis of resin AX2]
As the monomer, a monomer (a1-4-2), a monomer (a1-1-2), a monomer (III-2-A1), and a monomer (I-1) were used, and their molar ratios [monomer (a1-4-2) ): Monomer (a1-1-2): Monomer (III-2-A1): Monomer (I-1)], and mixed at a ratio of 30: 35: 5: 30. Was mixed with 1.5 times by mass of methyl isobutyl ketone with respect to the total mass of all the monomers. To the obtained mixture, azobisisobutyronitrile as an initiator was added in an amount of 7 mol% based on the total number of moles of all monomers, and the mixture was heated at 85 ° C. for about 5 hours to perform polymerization. Was. Thereafter, an aqueous solution of p-toluenesulfonic acid was added, and the mixture was stirred for 6 hours and then separated. The collected organic layer was poured into a large amount of n-heptane to precipitate a resin, and the resin was filtered and collected to obtain a resin AX2 (copolymer) having a weight average molecular weight of about 5.3 × 10 ³ in a yield of 65. %. This resin AX2 has the following structural units.

Synthesis Example 3 [Synthesis of resin AX3]
As monomers, monomer (a1-1-3), monomer (a1-2-2), monomer (a2-1-1), monomer (a3-1-1) and monomer (II-1) were used. The ratio [monomer (a1-1-3): monomer (a1-2-2): monomer (a2-1-1): monomer (a3-1-1): monomer (II-1)] is 28:14: The mixture was mixed so that the ratio became 10:38:10, and further, 1.5 parts by mass of methyl isobutyl ketone was mixed with the monomer mixture based on the total mass of all the monomers. To the resulting mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators at 1.2 mol% and 3.6 mol%, respectively, based on the total amount of monomers, and these were added to the mixture at 73%. Heated at ℃ C for about 5 hours. The obtained reaction mixture was poured into a large amount of a mixed solvent of methanol / water to precipitate a resin, and the resin was filtered. The obtained resin is again dissolved in methyl isobutyl ketone, and the resulting solution is poured into a mixed solvent of methanol and water to precipitate the resin, and the resin is filtered twice to perform a reprecipitation operation, whereby the weight average molecular weight of 6 is obtained. 0.0 × 10 ³ resin AX3 was obtained with a yield of 62%. This resin AX3 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 A12, AX1 to AX3: Resin A1 to Resin A12, Resin AX1 to Resin AX3
<Acid generator (B)>
B1-43: Salt represented by formula (B1-43) (synthesized according to the example of JP-A-2016-47815)
<Quencher (C)>
(Salt that generates an acid whose acidity is weaker than the acid generated from the acid generator)
D1: synthesized by the method described in JP-A-2011-39502
<Solvent>
Propylene glycol monomethyl ether acetate 400 parts Propylene glycol monomethyl ether 150 parts γ-butyrolactone 5 parts

(Evaluation of electron beam exposure of resist composition: alkali development)
A 6-inch silicon wafer was treated at 60 ° C. for 60 seconds using hexamethyldisilazane on a direct hot plate. This silicon wafer was spin-coated with a resist composition such that the thickness of the composition layer was 0.04 μm. Thereafter, the composition was prebaked on a direct hot plate at a temperature shown in the “PB” column of Table 1 for 60 seconds to form a composition layer. The composition layer formed on the wafer is subjected to a line and space pattern (pitch: 36 to 72 nm) by using an electron beam lithography machine (“ELS-F125 125 keV” manufactured by Elionix Inc.) and changing the exposure stepwise. / Line width 18 to 36 nm).
After exposure, post-exposure baking is performed on a hot plate at a temperature shown in the “PEB” column of Table 1 for 60 seconds, and paddle development is further performed with a 2.38% by mass aqueous solution of tetramethylammonium hydroxide for 60 seconds. Thus, a resist pattern was obtained.
In the obtained resist pattern, the exposure amount at which the line width and the space width of the 36 nm line and space pattern were 1: 1 was defined as the effective sensitivity.

<Resolution evaluation>
In the effective sensitivity, the resist pattern was observed with a scanning electron microscope, and the resolution was defined as the minimum line width resolved. Table 2 shows the results. Indicates the resolution (nm).

As compared with Comparative Compositions 1 to 3, the resolutions of the resist patterns of Compositions 1 to 5 and 7 to 9 were smaller, and the resolution evaluation was better.

(Evaluation of electron beam exposure of resist composition: development with butyl acetate)
A 6-inch silicon wafer was treated at 60 ° C. for 60 seconds using hexamethyldisilazane on a direct hot plate. This silicon wafer was spin-coated with a resist composition such that the thickness of the composition layer was 0.04 μm. Thereafter, the composition was prebaked on a direct hot plate at a temperature shown in the “PB” column of Table 1 for 60 seconds to form a composition layer. The composition layer formed on the wafer is subjected to an electron beam lithography machine (“ELS-F125 125 keV” manufactured by Elionix Co., Ltd.), the exposure amount is changed stepwise, and after development, the line and space pattern (pitch) is changed. Direct writing was performed so as to be 36 to 72 nm / line width 18 to 36 nm.
After the exposure, post-exposure baking was performed on a hot plate at a temperature shown in the “PEB” column of Table 1 for 60 seconds. Next, a resist pattern was obtained by developing the composition layer on the silicon wafer by a dynamic dispense method at 23 ° C. for 20 seconds using butyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a developing solution. .
In the obtained resist pattern, the exposure amount at which the line width and the space width of the 36 nm line and space pattern were 1: 1 was defined as the effective sensitivity.

<Resolution evaluation>
In the effective sensitivity, the resist pattern was observed with a scanning electron microscope, and the resolution was defined as the minimum line width resolved. Table 3 shows the results. Indicates the resolution (nm).

Compared with Comparative Compositions 1 to 3, the resolutions of the resist patterns of Compositions 3 to 6 and 10 to 12 were small, and the resolution evaluation was good.

  INDUSTRIAL APPLICABILITY The resin of the present invention and a resist composition containing the same are suitable for fine processing of semiconductors and are extremely useful industrially because a resist pattern having good resolution can be obtained.

Claims (6)

A structural unit represented by the formula (I), a structural unit having a group represented by the formula (II-x), a structural unit represented by the formula (a1-1), and a structural unit represented by the formula (a1-2) A resin comprising at least one structural unit selected from the group consisting of the following structural units and a structural unit represented by Formula (a2-A).
[In the formula (I),
R ¹ represents a hydrogen atom or a methyl group.
A ¹ represents a single bond or ^* -CO-O-, and * represents a bonding site to the carbon atom to which -R ¹ is bonded.
R ² represents a halogen atom, a hydroxy group, a haloalkyl group having 1 to 4 carbon atoms or an alkyl group having 1 to 12 carbon atoms, and -CH _2- contained in the alkyl group is -O- or -CO-. It may be replaced.
mi represents an integer of any of 1 to 3.
ni represents an integer of 0 to 4, when ni is 2 or more, plural R ² may be the same or different from each other. Here, mi + ni ≦ 5. ]
[In the formula (II-x),
Ring W ¹ represents a heterocyclic ring having 2 to 36 carbon atoms, and a hydrogen atom contained in the heterocyclic ring is a halogen atom, a hydroxy group, a hydrocarbon group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. may be substituted with an alkylcarbonyloxy group having 2 to 4 alkylcarbonyl group or a carbon number of 2 to 4 carbon atoms, -CH 2 contained in the heterocyclic and hydrocarbon groups _- is, -O-, -S -, - it may be replaced by CO- or NR ^c group.
R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ]
[In the formulas (a1-1) and (a1-2),
L ^a1 and ^{L a2} each independently, -O- or _{* -O- (CH 2) k1 -CO} -O- the stands, k1 represents an integer of 1-7, * the binding of -CO- Represent hand.
R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
m1 represents any integer of 0 to 14.
n1 represents any integer of 0-10.
n1 ′ represents any integer of 0 to 3. ]
[In the formula (a2-A),
^Ra50 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 represents a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl. Represents an oxy group or a methacryloyloxy group.
A ^a50 represents a single bond or ^{* -X a51 - (A a52 -X} a52) nb - represents, * represents a binding site to the carbon atom to which -R ^a50 binds.
A ^a52 represents an alkanediyl group having 1 to 6 carbon atoms.
X ^a51 and X ^a52 each independently represent -O-, ^-CO -O-, or -O-CO-.
nb represents 0 or 1.
mb represents any integer of 0-4. When mb is any integer of 2 or more, a plurality of R ^a51 may be the same or different. ] The resin according to claim 1, wherein the structural unit having a group represented by the formula (II-x) is a structural unit represented by the formula (IIA).
[In formula (IIA), ^Rx represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
A ^X is a single bond, ^{-A X1} - * or ^{-CO-O-A X1 - *} (* represents a binding position with a carbonyl group.) Represents the.
A ^X1 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, _-CH 2 contained in the saturated hydrocarbon group - is -O -, - CO- or -N ^{(R d)} - in It may be replaced.
Ring W ¹ represents a heterocyclic ring having 2 to 36 carbon atoms, and a hydrogen atom contained in the heterocyclic ring is a halogen atom, a hydroxy group, a hydrocarbon group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. may be substituted with an alkylcarbonyloxy group having 2 to 4 alkylcarbonyl group or a carbon number of 2 to 4 carbon atoms, -CH 2 contained in the heterocyclic and hydrocarbon groups _- is, -O-, -S -, - it may be replaced by CO- or NR ^c group.
R ^c and R ^d each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ]   A resist composition comprising the resin according to claim 1 and an acid generator. The resist composition according to claim 3, wherein the acid generator contains a salt represented by the formula (B1).
[In the formula (B1),
Q ^b1 and Q ^b2 each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and —CH ₂ — contained in the divalent saturated hydrocarbon group may be replaced by —O— or —CO—. The hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Y represents a methyl group which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and-is included in the alicyclic hydrocarbon group. CH ₂ — may be replaced by —O—, —S (O) ₂ — or —CO—.
Z ⁺ represents an organic cation. ]   5. The resist composition according to claim 3, further comprising a salt that generates an acid having a lower acidity than the acid generated from the acid generator. (1) a step of applying the resist composition according to any one of claims 3 to 5 on a substrate;
(2) drying the composition after application to form a composition layer;
(3) a step of exposing the composition layer,
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern comprising: