JP2008169353A - Polymer for resist, resist composition and method for producing substrate on which resist pattern is formed - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist composition capable of forming resist films which have sufficient dry etching resistance, are high in sensitivity, resolution and light transmittance, are wide in focal depth margin, are little in defects, and can resist to thin resist films, to provide a polymer for resists, and to provide a method for producing a substrate on which a resist pattern is formed. <P>SOLUTION: The polymer for the resists, having constituting units (A1) represented by formula (1-1) is used. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resist polymer, a resist composition, and a method for producing a substrate on which a fine pattern is formed.

  In recent years, a resist pattern formed in a manufacturing process of a semiconductor element, a liquid crystal element, or the like has been rapidly miniaturized due to progress in lithography technology. As a technique for miniaturization, there is a reduction in wavelength of irradiation light. Specifically, the irradiation light has become shorter in wavelength from ultraviolet rays typified by conventional g-line (wavelength: 438 nm) and i-line (wavelength: 365 nm) to shorter wavelength DUV (Deep Ultra Violet). .

  Recently, KrF excimer laser (wavelength: 248 nm) lithography technology has been introduced, and ArF excimer laser (wavelength: 193 nm) lithography technology and EUV excimer laser (wavelength: 13 nm) lithography technology for further shortening the wavelength have been studied. . Furthermore, these immersion lithography techniques are also being studied. Also, as a different type of lithography technology, electron beam lithography technology has been energetically studied.

A “chemically amplified resist composition” containing a photoacid generator has been proposed as a high-resolution resist composition used for forming a resist pattern using the irradiation light or electron beam of the short wavelength. Improvement and development of amplification resist compositions are underway.
For example, as a chemically amplified resist polymer used in ArF excimer laser lithography, an acrylic polymer that is transparent with respect to light having a wavelength of 193 nm has attracted attention. As the acrylic polymer, for example, a polymer of (meth) acrylic acid ester having an adamantane skeleton in an ester portion and (meth) acrylic acid ester having a lactone skeleton in an ester portion has been proposed (Patent Document 1). 2).

However, when the acrylic polymer is used as a resist composition, there is a case where the depth of focus margin is not sufficient, and there is a possibility that the yield is reduced in the actual resist pattern forming process.
Further, when a resist pattern is formed by developing with an alkali developer, a development defect called defect may occur. Then, due to the defect, the resist pattern may be missing, causing circuit disconnection, defects, and the like, which may lead to a decrease in yield in the manufacturing process of the semiconductor element.
Further, there is a concern that the dry etching resistance is insufficient due to the thinning of the resist film.

As a polymer excellent in dry etching resistance, a polymer having a heteroaromatic ring has been proposed (Patent Documents 3 to 5, etc.).
However, especially in the case of ArF excimer laser (wavelength: 193 nm) lithography, the polymer often has insufficient light transmittance of the polymer at the exposure wavelength, which may adversely affect sensitivity, resolution, and the like.
JP 10-319595 A JP-A-10-274852 JP 2005-114968 A JP 2004-163877 A JP 2006-276458 A

  The present invention has high sensitivity and high resolution in DUV excimer laser lithography, etc., wide depth of focus, high light transmittance, few defects during development, and dry etching resistance that can withstand the thinning of resist films. To provide a resist composition capable of forming a resist film, a resist polymer from which the resist composition can be obtained, and a method for producing a substrate with a fine pattern on which a high-precision fine pattern can be formed Objective.

  The resist polymer of the present invention is characterized by having a structural unit (A1) represented by the following formula (1-1).

In formula (1-1), R ¹⁰ represents a hydrogen atom or a methyl group, and G represents a single bond, —C (═O) —O—, —O—, or —O—C (═O) —. L ¹ ′ represents a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms which may have a hetero atom, X ¹¹ represents an alkyl group having 1 to 6 carbon atoms, hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, represents an alkoxy group having 1 to 6 carbon atoms, alcohols esterified with the carboxy group of 1 to 6 carbon atoms or an amino group, the number of carbon atoms in X ¹¹ 1 -6 alkyl group is a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a carboxyl group esterified with an alcohol having 1 to 6 carbon atoms, a cyano group At least one group selected from the group consisting of a group and an amino group May have, h11 represents an integer of 0 to 4, when the h11 is 2 or ^{more, X 11} may be a different group respectively, g3 represents 0 or 1, Y is - C (R ¹²¹ ) (R ¹²² ) (R ¹²³ ) or —C (R ¹³¹ ) (R ¹³² ) —O—R ¹³³ is represented, and R ¹²¹ , R ¹²² , and R ¹²³ each represent (i) 4 carbon atoms. Represents a monovalent alicyclic hydrocarbon group of ˜20 or a derivative thereof or an alkyl group having 1 to 4 carbon atoms, and at least one of R ¹²¹ , R ¹²² and R ¹²³ is the alicyclic hydrocarbon group or Or (ii) a divalent alicyclic group having 4 to 20 carbon atoms, together with any two of R ¹²¹ , R ¹²² , and R ¹²³ bonded to each other, and the carbon atom to which each is bonded. Hydrocarbon group or its derivative And the remaining one of R ¹²¹ , R ¹²² , and R ¹²³ is an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms, or a derivative thereof, and R ¹³¹ , R ¹³² , and R ¹³³ are (i) R ¹³³ represents a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or an alkyl group having 1 to 4 carbon atoms, and R ¹³¹ and R ¹³² are Each represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or (ii) two of R ¹³¹ or R ¹³² and R ¹³³ are bonded to each other, together with the carbon atom to which each is bonded, 4 to 20 divalent alicyclic hydrocarbon groups or derivatives thereof are formed, and the remaining one of R ¹³¹ and R ¹³² represents a hydrogen atom.

The resist composition of the present invention comprises the resist polymer of the present invention.
The method for producing a substrate having a fine pattern according to the present invention comprises a step of applying the resist composition of the present invention on a substrate to be processed to form a resist film, and applying light having a wavelength of 250 nm or less to the resist film. The method includes a step of forming a latent image by irradiation and a step of developing the resist film on which the latent image is formed with a developer.

According to the resist polymer of the present invention, it has high sensitivity, high resolution, wide depth of focus, high light transmittance, few defects during development, and resistance to dry etching that can withstand thinning of the resist film. A resist composition capable of forming a resist film having the resist film can be obtained.
The resist composition of the present invention has high sensitivity and high resolution in DUV excimer laser lithography and the like, has a wide depth of focus margin, high light transmittance, few defects during development, and can withstand thinning of the resist film. A resist film having dry etching resistance can be formed.
According to the method for manufacturing a substrate on which a fine pattern is formed according to the present invention, a highly accurate fine pattern can be formed.

  In this specification, (meth) acrylic acid means acrylic acid or methacrylic acid.

<Resist polymer>
The resist polymer of the present invention has a structural unit (A1) having a naphthalene skeleton having an acid leaving group.
If necessary, the resist polymer of the present invention comprises a structural unit (A2) having a naphthalene skeleton having an acidic group, a structural unit (B) having a lactone skeleton, and a structural unit (C) having an acid-eliminating group. In addition, other structural units such as a structural unit (D) having a hydrophilic group may be included.

The acid leaving group is a group having a bond that is cleaved by an acid, and a part or all of the acid leaving group is released from the main chain of the polymer by cleavage of the bond.
The hydrophilic group is _{-C (CF} 3) 2 -OH, hydroxy group, at least one cyano group, methoxy group, carboxyl group and amino group.

(Structural unit (A1))
The structural unit (A1) is a structural unit represented by the following formula (1-1) and having a naphthalene skeleton having an acid leaving group.

g3 represents 0 or 1.
R ¹⁰ represents a hydrogen atom or a methyl group.
G represents a single bond, —C (═O) —O—, —O—, or —O—C (═O) —, and —C (═O) —O— or — from the viewpoint of polymerizability. O—C (═O) — is preferred.

L ¹ ′ represents a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms. The divalent hydrocarbon group may be linear, branched or cyclic, may have a substituent, and may have a hetero atom. Examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom, and a phosphorus atom. Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms include the following formulas (2-1) to (2-33).

As L ¹ ′, from the viewpoint of solubility in a resist solvent, a linear or branched divalent hydrocarbon group having 1 to 4 carbon atoms, — (CH ₂ CH ₂ O) _g21 CH ₂ CH ₂ —, or _{- (CH 2 CH (CH 3} ) O) g22 CH 2 CH (CH 3) - are preferred. g21 and g22 each represent an integer of 0 to 4, and 0 or 1 is preferable from the viewpoint of resolution.

Y represents -C (R ^<121> ) (R ^<122> ) (R ^<123> ), or -C (R ^<131> ) (R ^<132> )-O-R ^<133 >.
R ¹²¹ , R ¹²² , and R ¹²³ represent the following (i) or (ii).
(I) represents a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ¹²¹ , R ¹²² , and R ¹²³ At least one is the alicyclic hydrocarbon group or a derivative thereof.
(Ii) Any two of R ¹²¹ , R ¹²² , and R ¹²³ are bonded to each other, and together with the bonded carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof And the remaining one of R ¹²¹ , R ¹²² , and R ¹²³ not participating in the bond is a linear or branched alkyl group having 1 to 4 carbon atoms or a monovalent alicyclic group having 4 to 20 carbon atoms It is a hydrocarbon group or a derivative thereof.

R ¹³¹ , R ¹³² , and R ¹³³ represent the following (i) or (ii).
(I) R ¹³³ represents a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ¹³¹ and R ¹³² are each hydrogen. An atom or a linear or branched alkyl group having 1 to 4 carbon atoms is represented.
(Ii) Two of R ¹³¹ or R ¹³² and R ¹³³ are bonded to each other, and together with the carbon atoms to which each is bonded, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, The remaining one of R ¹³¹ and R ¹³² that did not participate in the bonding represents a hydrogen atom.

-C (R ¹²¹ ) (R ¹²² ) (R ¹²³ ) is preferably a structure represented by the following formulas (K-1) to (K-6) from the viewpoint of excellent line edge roughness. In terms of high resistance, structures represented by the following formulas (K-7) to (K-17) are preferable. Of these, the following formulas (K-2), (K-4), (K-6), (K-8), (K-11), and (K-13) are more preferable from the viewpoint of excellent sensitivity. .

-C (R ¹³¹ ) (R ¹³² ) -O-R ¹³³ is preferably a structure represented by the following formulas (J-1) to (J-24) from the viewpoint of excellent line edge roughness. From the viewpoint of high etching resistance, structures represented by the following formulas (J-25) to (J-52) are preferable.

h11 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of resolution.
X ¹¹ is an alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a carboxy esterified with an alcohol having 1 to 6 carbon atoms. Represents a group or an amino group. The alkyl group having 1 to 6 carbon atoms is a carboxyl group esterified with a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alcohol having 1 to 6 carbon atoms. It may have at least one group selected from the group consisting of a group, a cyano group and an amino group.
X ¹¹ is preferably a linear or branched alkyl group having 1 to 6 carbon atoms having a hydroxy group or a hydroxy group or a cyano group as a substituent, from the viewpoint of reducing defects and improving the resist pattern rectangularity.
If h11 is 2 or ^{more, X 11} may be a different group.

  When the resist polymer of the present invention has the structural unit (A1), when used as a resist composition for immersion exposure (particularly when the immersion liquid is pure water), the resist composition has a reduced defect. Has the effect of.

Since the structural unit (A1) has an acid leaving group, the resist polymer having the structural unit (A1) becomes soluble in alkali when the acid leaving group is eliminated. A pattern can be formed.
When the structural unit (A1) has a hydrophilic group, the resist pattern rectangularity tends to be good.
A structural unit having an acid-eliminable group (originally corresponding to the structural unit (C)) or a structural unit having a hydrophilic group (originally corresponding to the structural unit (D)). In addition, the structural unit represented by Formula (1-1) is the structural unit (A1).

  The proportion of the structural unit (A1) is preferably 2 mol% or more, more preferably 4 mol% or more, in the structural unit (100 mol%) of the resist polymer in terms of dry etching resistance and refractive index. Further, in terms of sensitivity and resolution, 20 mol% or less is preferable, 15 mol% or less is more preferable, and 10 mol% or less is more preferable.

The resist polymer of the present invention may have two or more different types of structural units (A1).
As the structural unit (A1), a structural unit (A11) represented by the following formula (1-2) is preferable from the viewpoint of transparency to 193 nm excimer laser light.

In formula (1-2), R ¹⁰ , G, L ¹ ′, Y, and g3 are respectively synonymous with formula (1-1).
The structural unit (A11) is a structural unit in which h11 in the formula (1-1) is 0 and a linking group and a substituent are bonded only to the 2nd and 6th positions of the naphthalene ring.

  The resist polymer having the structural unit (A11) can be produced by polymerizing a monomer containing the monomer (a1) represented by the following formula (1-3).

In formula (1-3), R ¹⁰ , G, L ¹ ′, Y, and g3 have the same meaning as in formula (1-1).
Examples of the monomer (a1) include monomers represented by the following formulas (8-1) to (8-19). In formulas (8-1) to (8-19), R represents a hydrogen atom or a methyl group.

  Among these, from the viewpoint of line edge roughness, monomers represented by formulas (8-1) to (8-6), and geometrical isomers and optical isomers thereof are preferable.

(Structural unit (A2))
The structural unit (A2) is a structural unit having a naphthalene skeleton having an acidic group (excluding the structural unit (A1)).
The structural unit (A2) is preferably used as a structural component of the resist polymer because it exhibits the effect of developing dry etching resistance.

  Since the resist polymer of the present invention has the structural unit (A2), the light transmittance at 193 nm can be increased, and in particular, when the immersion liquid is pure water, the defect of the resist composition is reduced. Play.

Since the structural unit (A2) has an acidic group, the resist polymer having the structural unit (A2) becomes soluble in alkali, and a resist pattern can be formed.
In addition, since the structural unit (A2) has an acidic group, that is, a hydrophilic group, the resist pattern rectangularity tends to be good.

  The proportion of the structural unit (A2) is preferably 2 mol% or more, more preferably 4 mol% or more in the structural unit (100 mol%) of the resist polymer from the viewpoint of defect or line edge roughness. Moreover, from the point of the light transmittance in 193 nm, 20 mol% or less is preferable, 15 mol% or less is more preferable, and 10 mol% or less is further more preferable.

  The total of the proportion of the structural unit (A1) and the proportion of the structural unit (A2) is preferably 5 mol% or more in the structural unit (100 mol%) of the resist polymer, from the viewpoint of dry etching resistance. % Or more is more preferable. Moreover, from the point of the light transmittance in 193 nm, 30 mol% or less is preferable, 20 mol% or less is more preferable, and 17 mol% or less is further more preferable.

The resist polymer of the present invention may have two or more different types of structural units (A2).
As the structural unit (A2), the structural unit (A21) represented by the following formula (1-4) is preferable from the viewpoint of sensitivity or dry etching resistance. From the viewpoint of defect or line edge roughness, the following formula (1- The structural unit (A22) represented by 6) is more preferred, and the structural unit (A23) represented by the following formula (1-7) is more preferred.

g2 represents 0 or 1.
R ¹¹ represents a hydrogen atom or a methyl group.
G ¹ represents a single bond, —C (═O) —O—, —O—, or —O—C (═O) —, and —C (═O) —O—, Or -O-C (= O)-is preferable.

L ² represents a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms. The divalent hydrocarbon group may be linear, branched, or cyclic, and may have a hetero atom. Examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom, and a phosphorus atom. Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms include formulas (2-1) to (2-33).

L ² is a linear or branched divalent hydrocarbon group having 1 to 4 carbon atoms, — (CH ₂ CH ₂ O) _g31 CH ₂ CH ₂ —, or from the viewpoint of solubility in a resist solvent. _{- (CH 2 CH (CH 3} ) O) g32 CH 2 CH (CH 3) - it is preferred. g31 and g32 each represent an integer of 0 to 4, and 0 or 1 is preferable from the viewpoint of resolution.
When G ¹ is —C (═O) —O—, from the viewpoint of sensitivity, L ² may be —C (CH ₃ ) ₂ —, —C (CH ₃ ) ₂ —CH ₂ —, and —C ( More preferred is at least one selected from CH ₃ ) (CH ₂ CH ₃ ) —.

Y ¹ represents —CH ₂ —C (═O) —OH, —OH.
L ² ″ represents a straight-chain hydrocarbon group having 1 to 4 carbon atoms.

  The polymer having the structural unit (A21) can be produced by polymerizing a monomer containing the monomer (a2) represented by the following formula (1-5).

In formula (1-5), R ¹¹ , G ¹ , L ² , g 2 and Y ¹ have the same meaning as in formula (1-4).
Examples of the monomer (a2) include monomers represented by the following formulas (8-101) to (8-159). In formulas (8-101) to (8-159), R represents a hydrogen atom or a methyl group.

  Among these, from the point of sensitivity, formulas (8-111) to (8-112), formulas (8-115) to (8-120), formulas (8-123) to (8-128), formula ( Monomers represented by 8-139) to (8-140), formulas (8-142) to (8-145), and formula (8-155), and geometric isomers and optical isomers thereof are preferable. .

(Structural unit (B))
The structural unit (B) is a structural unit having a lactone skeleton (excluding the structural units (A1) and (A2)).
The structural unit (B) is preferably used as a structural component of the resist polymer because it exerts an effect of developing adhesion to the substrate.

When the structural unit (B) has an acid leaving group, it tends to have better sensitivity.
When the structural unit (B) has a hydrophilic group, the resist pattern rectangularity and sensitivity tend to be good.
A structural unit having an acid-eliminable group (originally corresponding to the structural unit (C)) or a structural unit having a hydrophilic group (originally corresponding to the structural unit (D)). In addition, the structural unit having a lactone skeleton is the structural unit (B).

  The proportion of the structural unit (B) is preferably 30 mol% or more, more preferably 35 mol% or more in the structural unit (100 mol%) of the resist polymer, from the viewpoint of adhesion to the substrate. Moreover, from the point of a sensitivity and resolution, 60 mol% or less is preferable, 55 mol% or less is more preferable, and 50 mol% or less is further more preferable.

The resist polymer of the present invention may have two or more different types of structural units (B).
The structural unit (B) is preferably at least one selected from the group consisting of the following formulas (4-1) to (4-6) from the viewpoint of sensitivity or dry etching resistance.

Formula (4-1):
R ⁴¹ represents a hydrogen atom or a methyl group.
R ⁴⁰¹ and R ⁴⁰² represent the following (i) or (ii).
(I) Each represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms.
(Ii) —O—, —S—, —NH— or a methylene chain [— (CH ₂ ) _j — (j represents an integer of 1 to 6) formed by combining R ⁴⁰¹ and R ⁴⁰² . )].

i represents 0 or 1;
n5 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ⁵ is a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alcohol having 1 to 6 carbon atoms. Represents an esterified carboxy group or amino group. A linear or branched alkyl group having 1 to 6 carbon atoms is a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alcohol having 1 to 6 carbon atoms as a substituent. It may have at least one group selected from the group consisting of an esterified carboxy group, a cyano group, and an amino group. When n5 is 2 or more, X ⁵ may be a different group.
m represents 1 or 2, and 1 is preferable from the viewpoint of sensitivity and resolution.

Formula (4-2):
^R42 represents a hydrogen atom or a methyl group.
R ²⁰¹ and R ²⁰² each represent a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms. From the viewpoint of high solubility in the solvent, a hydrogen atom, a methyl group, an ethyl group or an isopropyl group is preferable.

A ¹ and A ² represent the following (i) or (ii).
(I) Each represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms.
(Ii) ^{A 1} and ^{A 2} formed by bonding, -O -, - S -, - NH- or a methylene chain _{[- (CH 2) k -} (k represents an integer of 1-6. )].
The ^{A 1,} A ^2, _-CH ² in terms high dry etching resistance, are formed bonded to -, - _{CH 2 CH} 2 - is preferred, in terms of high solubility in resist solvents, bound -O- formed is preferable.

n6 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ⁶ is a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alcohol having 1 to 6 carbon atoms. It represents an esterified carboxy group, cyano group, or amino group. The linear or branched alkyl group having 1 to 6 carbon atoms is a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or a cyano group. And at least one group selected from the group consisting of amino groups. When n6 is 2 or more, X ⁶ may be a different group.

Formula (4-3):
R ⁴³ represents a hydrogen atom or a methyl group.
R ²⁰³ and R ²⁰⁴ each represent a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms. From the viewpoint of high solubility in the solvent, a hydrogen atom, a methyl group, an ethyl group, or an isopropyl group is preferable.

A ³ and A ⁴ represent the following (i) or (ii).
(I) Each represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms.
(Ii) and ^{A 3} and ^{A 4} is formed by bonding, -O -, - S -, - NH- or a methylene chain _{[- (CH 2) l -} (l represents an integer of 1-6. )].
As A ³ and A ⁴ , —CH ₂ — or —CH ₂ CH ₂ — formed by bonding is preferable from the viewpoint of high dry etching resistance, and bonded from the viewpoint of high solubility in a resist solvent. -O- formed is preferable.

n7 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ⁷ is a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alcohol having 1 to 6 carbon atoms. It represents an esterified carboxy group, cyano group, or amino group. The linear or branched alkyl group having 1 to 6 carbon atoms is a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or a cyano group. And at least one group selected from the group consisting of amino groups. When n7 is 2 or more, X ⁷ may be a different group.

Formula (4-4):
R ⁴⁴ represents a hydrogen atom or a methyl group.
R ²⁰⁵ , R ²⁰⁶ , and R ²⁰⁷ each represent a hydrogen atom or a methyl group, and a hydrogen atom is preferable from the viewpoint of high solubility in a resist solvent.
Y ¹¹ , Y ¹² and Y ¹³ each represent —CH ₂ — or —C (═O) —O—, and at least one of Y ¹¹ , Y ¹² and Y ¹³ represents —C (═O) —. Represents O-. As Y ¹¹ , Y ¹² and Y ¹³ , it is preferable that one is —C (═O) —O— and the remaining two are —CH ₂ — from the viewpoint of high adhesion to the substrate surface and the like. .

n8 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ⁸ is a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alcohol having 1 to 6 carbon atoms. It represents an esterified carboxy group, cyano group, or amino group. The linear or branched alkyl group having 1 to 6 carbon atoms is a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or a cyano group. And at least one group selected from the group consisting of amino groups. When n8 is 2 or more, X ⁸ may be a different group.

Formula (4-5):
R ⁹¹ and R ⁹² represent the following (i) or (ii).
(I) Each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms.
^{(Ii) R 91} and ^{R 92} is formed by bonding, -O -, - S -, - NH-, or a methylene chain _{[- (CH 2) t -} (t is an integer from 1 to 6 .)].
R ⁹¹ and R ⁹² are each preferably a hydrogen atom or a methyl group from the viewpoint of high solubility in a resist solvent.

m1 represents 1 or 2, and 1 is preferable from the viewpoint of sensitivity and resolution.
R ⁹³ and R ⁹⁴ each represent a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms. From the viewpoint of high solubility in the solvent, a hydrogen atom or a methyl group is preferable.

Formula (4-6):
R ⁴⁵ represents a hydrogen atom or a methyl group.
R ²⁰⁸ and R ²⁰⁹ each represent a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms. From the viewpoint of high solubility in the solvent, a hydrogen atom, a methyl group, an ethyl group, or an isopropyl group is preferable.
R ²¹⁰ and R ²¹¹ each represent a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, and from the viewpoint of high solubility in a resist solvent, a hydrogen atom, a methyl group, an ethyl group, or isopropyl Groups are preferred.

A ⁵ and A ⁶ represent the following (i) or (ii).
(I) Each represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms.
(Ii) and ^{A 5} and ^{A 6} is formed by bonding, -O -, - S -, - NH- or a methylene chain _{[- (CH 2) k1 -} (k1 represents an integer of 1-6. )].
As A ⁵ and A ⁶ , —CH ₂ — or —CH ₂ CH ₂ — formed by bonding is preferable in view of high dry etching resistance, and bonded in terms of high solubility in a resist solvent. -O- formed is preferable.

Y ²¹ and Y ²² each represent —CH ₂ — or —C (═O) —, and at least one of Y ²¹ and Y ²² represents —C (═O) —. As Y ²¹ and Y ²² , it is preferable that one is —C (═O) — and the remaining one is —CH ₂ — from the viewpoint of high adhesion to the substrate surface and the like.

n9 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ⁹ is a linear or branched alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alcohol having 1 to 6 carbon atoms. It represents an esterified carboxy group, cyano group, or amino group. The linear or branched alkyl group having 1 to 6 carbon atoms is a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or a cyano group. And at least one group selected from the group consisting of amino groups. When n9 is 2 or more, X ⁹ may be a different group.

The polymer having the structural unit (B) can be produced by polymerizing a monomer containing the monomer (b) that gives the structural unit (B).
Examples of the monomer (b) include monomers represented by the following formulas (10-1) to (10-29). In formulas (10-1) to (10-29), R represents a hydrogen atom or a methyl group.

  Among these, in terms of sensitivity, the monomers represented by the formulas (10-1) to (10-3) and the formula (10-5), and geometric isomers and optical isomers thereof are preferable. In terms of etching resistance, Formula (10-7), Formula (10-9), Formula (10-10), Formula (10-12), Formula (10-14), Formula (10-24) to (10) -26), monomers represented by the formula (10-29), and geometric isomers and optical isomers thereof are preferable. From the viewpoint of solubility in a resist solvent, the formula (10-8) and the formula Monomers represented by (10-13), formulas (10-16) to (10-23) and formula (10-28), and geometric isomers and optical isomers thereof are more preferable.

(Structural unit (C))
The structural unit (C) is a structural unit having an acid leaving group (excluding the structural units (A1), (A2), and (B)).
The structural unit (C) is a component that is soluble in an alkali by an acid, and has an effect of enabling the formation of a resist pattern. Therefore, the structural unit (C) is preferably used as a structural component of a resist polymer.
When the structural unit (C) has a hydrophilic group, it tends to have better sensitivity.
Even a structural unit having a hydrophilic group (originally corresponding to the structural unit (D)), the structural unit having an acid-eliminable group is the structural unit (C).

  The proportion of the structural unit (C) is preferably 20 mol% or more, more preferably 25 mol% or more in the structural unit (100 mol%) of the resist polymer from the viewpoint of sensitivity and resolution. Moreover, 60 mol% or less is preferable from the point of the adhesiveness to a substrate surface etc., 55 mol% or less is more preferable, and 50 mol% or less is more preferable.

The resist polymer of the present invention may have two or more different types of structural units (C).
As the structural unit (C), from the viewpoint of high dry etching resistance, the following formula (3-1-1), formula (3-2-1), formula (3-3-1), formula (3-4-) 1), at least one selected from the group consisting of formula (3-5-1), formula (3-6-1), formula (3-7-1) and formula (3-8-1) is preferred.

Formula (3-1-1):
R ³¹ represents a hydrogen atom or a methyl group.
R ¹ represents an alkyl group having 1 to 3 carbon atoms, and is preferably a methyl group, an ethyl group, or an isopropyl group from the viewpoint of sensitivity and resolution.
n1 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ¹ represents a linear or branched alkyl group having 1 to 6 carbon atoms. When n1 is 2 or more, X ¹ may be a different group.

Formula (3-2-1):
R ³² represents a hydrogen atom or a methyl group.
R ² and R ³ each represent an alkyl group having 1 to 3 carbon atoms, and are preferably a methyl group, an ethyl group, or an isopropyl group from the viewpoint of sensitivity and resolution.
n2 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ² represents a linear or branched alkyl group having 1 to 6 carbon atoms. When n2 is 2 or more, X ² may be a different group.

Formula (3-3-1):
R ³³ represents a hydrogen atom or a methyl group.
R ⁴ represents an alkyl group having 1 to 3 carbon atoms, and is preferably a methyl group, an ethyl group, or an isopropyl group from the viewpoint of sensitivity and resolution.
q represents 0 or 1, and is preferably 1 in terms of high dry etching resistance, and is preferably 0 in terms of high solubility in a resist solvent.
R ³³¹ , R ³³² , R ³³³ , and R ³³⁴ each represent a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms. From the viewpoint of high solubility in a resist solvent, a hydrogen atom or a methyl group , Ethyl group, or isopropyl group is preferable.

V ¹ and V ² each represent —O—, —S—, —NH—, or a methylene chain [— (CH ₂ ) _u1 — (u1 represents an integer of 1 to 6)], and has dry etching resistance. From the high point, —CH ₂ — or —CH ₂ CH ₂ — is preferable.
n3 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ³ represents a linear or branched alkyl group having 1 to 6 carbon atoms. When n3 is 2 or more, X ³ may be a different group.

Formula (3-4-1):
R ³⁴ represents a hydrogen atom or a methyl group.
R ⁵ represents an alkyl group having 1 to 3 carbon atoms, and is preferably a methyl group, an ethyl group, or an isopropyl group from the viewpoint of sensitivity and resolution.
n4 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ⁴ represents a linear or branched alkyl group having 1 to 6 carbon atoms. When n4 is 2 or more, X ⁴ may be a different group.
r represents an integer of 0 to 2, preferably 1 in terms of high dry etching resistance, and preferably 0 in terms of high solubility in a resist solvent.

Formula (3-5-1):
R ³⁵ represents a hydrogen atom or a methyl group.
q3 represents 0 or 1, and is preferably 1 from the viewpoint of high dry etching resistance, and preferably 0 from the viewpoint of high solubility in a resist solvent.
R ³⁵¹ , R ³⁵² , R ³⁵³ , and R ³⁵⁴ each represent a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms. From the viewpoint of high solubility in a resist solvent, a hydrogen atom or a methyl group , Ethyl group, or isopropyl group is preferable.

V ³ and V ⁴ each represent —O—, —S—, —NH—, or a methylene chain [— (CH ₂ ) _u11 — (u11 represents an integer of 1 to 6)], and has dry etching resistance. From the high point, —CH ₂ — or —CH ₂ CH ₂ — is preferable.
n51 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ⁵¹ represents a linear or branched alkyl group having 1 to 6 carbon atoms. When n51 is 2 or more, X ⁵¹ may be a different group.

R ³⁵⁵ , R ³⁵⁶ , and R ³⁵⁷ represent the following (i) or (ii).
(I) each represents a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ³⁵⁵ , R ³⁵⁶ , or R ³⁵⁷ At least one of these is the alicyclic hydrocarbon group or a derivative thereof.
(Ii) any two of R ³⁵⁵ , R ³⁵⁶ , and R ³⁵⁷ are bonded to each other, and together with the carbon atoms to which each is bonded, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof And the remaining one of R ³⁵⁵ , R ³⁵⁶ , and R ³⁵⁷ that is not involved in the bond is a linear or branched alkyl group having 1 to 4 carbon atoms, or a monovalent alicyclic ring having 4 to 20 carbon atoms Represents a hydrocarbon group or its derivative.
-C (R ³⁵⁵ ) (R ³⁵⁶ ) (R ³⁵⁷ ) is preferably a structure represented by formulas (K-1) to (K-6) in terms of excellent line edge roughness, and is resistant to dry etching. Is high, the structures represented by the formulas (K-7) to (K-17) are preferable.

Formula (3-6-1):
R ³⁶ represents a hydrogen atom or a methyl group.
q4 represents 0 or 1, preferably 1 from the viewpoint of high dry etching resistance, and preferably 0 from the viewpoint of high solubility in a resist solvent.
R ³⁶¹ , R ³⁶² , R ³⁶³ , and R ³⁶⁴ each represent a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms. From the viewpoint of high solubility in a resist solvent, a hydrogen atom or a methyl group , An ethyl group, or an isopropyl group is preferable.

V ⁵ and V ⁶ each represent —O—, —S—, —NH—, or a methylene chain [— (CH ₂ ) _u12 — (u12 represents an integer of 1 to 6)], and has dry etching resistance. From the high point, —CH ₂ — or —CH ₂ CH ₂ — is preferable.
n61 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ⁶¹ represents a linear or branched alkyl group having 1 to 6 carbon atoms. When n61 is 2 or more, X ⁶¹ may be a different group.

R ³⁶⁷ represents a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms.
R ³⁶⁵ and R ³⁶⁶ represent the following (i) or (ii).
(I) Each represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.
(Ii) Two of R ³⁶⁵ or R ³⁶⁶ and R ³⁶⁷ are bonded to each other, and together with the carbon atom to which each is bonded, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, The remaining one of R ³⁶⁵ and R ³⁶⁶ that was formed and did not participate in bonding represents a hydrogen atom.
-C (R ³⁶⁵ ) (R ³⁶⁶ ) -O-R ³⁶⁷ is preferably a structure represented by formulas (J-1) to (J-24) in terms of excellent line edge roughness, and dry etching. In terms of high resistance, structures represented by formulas (J-25) to (J-52) are preferable.

Formula (3-7-1):
R ³⁷ represents a hydrogen atom or a methyl group.
R ³⁷³ represents a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a linear or branched alkyl group having 1 to 4 carbon atoms.

R ³⁷¹ and R ³⁷² represent the following (i) or (ii).
(I) Each represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.
(Ii) R ³⁷¹ or R ³⁷² and R ³⁷³ are bonded to each other, and together with the carbon atoms to which each is bonded, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, The remaining one of R ³⁷¹ and R ³⁷² that was formed and did not participate in bonding represents a hydrogen atom.
-C (R ³⁷¹ ) (R ³⁷² ) -O-R ³⁷³ is preferably a structure represented by formulas (J-1) to (J-24) from the viewpoint of excellent line edge roughness. In terms of high resistance, structures represented by formulas (J-25) to (J-52) are preferable.

Formula (3-8-1):
^R38 represents a hydrogen atom or a methyl group.
R ³⁸¹ , R ³⁸² and R ³⁸³ each represent a linear or branched alkyl group having 1 to 4 carbon atoms.

The polymer having the structural unit (C) can be produced by polymerizing a monomer containing the monomer (c) that gives the structural unit (C).
Examples of the monomer (c) include monomers represented by the following formulas (9-1) to (9-224). In formulas (9-1) to (9-224), R and R ′ each represent a hydrogen atom or a methyl group.

In addition to the above monomers, methoxymethyl (meth) acrylate and 1-ethoxyethyl (meth) acrylate may be mentioned.
Among these, in terms of sensitivity and resolution, Expressions (9-1) to (9-3), Expression (9-5), Expression (9-16), Expression (9-19), Expression (9-20) ), Formula (9-22), Formula (9-23), Formula (9-25) to (9-28), Formula (9-30), Formula (9-31), Formula (9-33), Monomers represented by formula (9-34) and formulas (9-102) to (9-129), and geometric isomers and optical isomers thereof are preferred, and formula (9-1), formula (9) -2), Formula (9-16), Formula (9-20), Formula (9-23), Formula (9-28), Formula (9-31), Formula (9-34), Formula (9- 109), a monomer represented by formula (9-111), formula (9-114) to (9-117), formula (9-125), formula (9-128) and formula (9-129). Is particularly preferred.

  Moreover, in the point which is excellent in line edge roughness, Formula (9-35)-(9-40), Formula (9-52)-(9-62), Formula (9-76)-(9-88) , Monomers represented by formulas (9-130) to (9-135), formulas (9-147) to (9-157), formulas (9-171) to (9-183), and these Geometric isomers and optical isomers are preferred.

Moreover, in the point which is excellent in dry etching tolerance, Formula (9-41)-(9-51), Formula (9-63)-(9-75), Formula (9-89)-(9-101) , Monomers represented by formulas (9-136) to (9-146), formulas (9-158) to (9-170), formulas (9-184) to (9-196), and these Geometric isomers and optical isomers are preferred.
In addition, in terms of good resist pattern rectangularity, monomers represented by formulas (9-197) to (9-224), and geometric isomers and optical isomers thereof are preferable.

(Structural unit (D))
The structural unit (D) is a structural unit having a hydrophilic group (excluding the structural units (A1), (A2), (B), and (C)).
The structural unit (D) is preferably used as a structural unit of the resist polymer in order to reduce the defects of the resist composition and improve the resist pattern rectangularity.

  The proportion of the structural unit (D) is preferably from 5 to 30 mol%, more preferably from 10 to 25 mol%, in the structural unit (100 mol%) of the resist polymer from the viewpoint of the resist pattern rectangularity.

The resist polymer of the present invention may have two or more different types of structural units (D).
The structural unit (D) is preferably at least one selected from the group consisting of the following formulas (5-1) to (5-7) from the viewpoint of high dry etching resistance.

Formula (5-1):
R ⁵¹ represents a hydrogen atom or a methyl group.
R ⁵⁰¹ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and is preferably a methyl group, an ethyl group, or an isopropyl group in terms of sensitivity and resolution, and in terms of high solubility in a resist solvent, Atoms are preferred.

n51 represents an integer of 1 to 4, and 1 is preferable from the viewpoint of high dry etching resistance.
X ⁵¹ is a linear or branched alkyl group having 1 to 6 carbon atoms, —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, a carboxy group, an acyl group having 1 to 6 carbon atoms, or 1 to 1 carbon atoms. 6 represents an alkoxy group, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or an amino group. Linear or branched alkyl group having 1 to 6 carbon atoms, _-C as a substituent _(CF 3) 2 -OH, hydroxy group, a cyano group, a carboxy group, an acyl group having 1 to 6 carbon atoms, 1 to carbon atoms It may have at least one group selected from the group consisting of a carboxy group esterified with 6 alcohols and an amino group. When n51 is 2 or more, X ⁵¹ may be a different group.
X ⁵¹ is preferably —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, or a methoxy group from the viewpoint of good resist pattern shape.

Formula (5-2):
R ⁵² represents a hydrogen atom or a methyl group.
n52 represents an integer of 1 to 4, and 1 is preferable from the viewpoint of high dry etching resistance.
X ⁵² represents a linear or branched alkyl group having 1 to 6 carbon atoms, —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, a carboxy group, an acyl group having 1 to 6 carbon atoms, 6 represents an alkoxy group, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or an amino group. Linear or branched alkyl group having 1 to 6 carbon atoms, _-C as a substituent _(CF 3) 2 -OH, hydroxy group, a cyano group, a carboxy group, an acyl group having 1 to 6 carbon atoms, 1 to carbon atoms It may have at least one group selected from the group consisting of a carboxy group esterified with 6 alcohols and an amino group. When n52 is 2 or more, X ⁵² may be a different group.
X ⁵² is preferably —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, or a methoxy group from the viewpoint of good resist pattern shape.

Formula (5-3):
R ⁵³ represents a hydrogen atom or a methyl group.
R ⁵⁰² represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and is preferably a methyl group, an ethyl group, or an isopropyl group in terms of sensitivity and resolution, and in terms of high solubility in a resist solvent, Atoms are preferred.

q1 represents 0 or 1, and 1 is preferable from the viewpoint of high dry etching resistance, and 0 is preferable from the viewpoint of high solubility in a resist solvent.
R ^{531 to} R ⁵³⁴ each represent a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, and from the viewpoint of high solubility in a resist solvent, a hydrogen atom, a methyl group, an ethyl group, or isopropyl Groups are preferred.
W ¹ and W ² each represent —O—, —S—, —NH—, or a methylene chain [— (CH ₂ ) _u2 — (u2 represents an integer of 1 to 6)], and has dry etching resistance. From the high point, —CH ₂ — or —CH ₂ CH ₂ — is preferable.

n53 represents an integer of 1 to 4, and 1 is preferable from the viewpoint of high dry etching resistance.
X ⁵³ is a C 1-6 linear or branched alkyl group, —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, a carboxy group, a C 1-6 acyl group, a C 1-6 6 represents an alkoxy group, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or an amino group. Linear or branched alkyl group having 1 to 6 carbon atoms, _-C as a substituent _(CF 3) 2 -OH, hydroxy group, a cyano group, a carboxy group, an acyl group having 1 to 6 carbon atoms, 1 to carbon atoms It may have at least one group selected from the group consisting of a carboxy group esterified with 6 alcohols and an amino group. When n53 is 2 or more, X ⁵³ may be a different group.
X ⁵³ is preferably —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, or a methoxy group from the viewpoint of good resist pattern shape.

Formula (5-4):
R ⁵⁴ represents a hydrogen atom or a methyl group.
R ⁵⁰³ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and is preferably a methyl group, an ethyl group, or an isopropyl group in terms of sensitivity and resolution, and a hydrogen atom in terms of high solubility in a resist solvent. Atoms are preferred.
r1 represents an integer of 0 to 2, preferably 1 from the viewpoint of high dry etching resistance, and preferably 0 from the viewpoint of high solubility in a resist solvent.

n54 represents an integer of 1 to 4, and 1 is preferable from the viewpoint of high dry etching resistance.
X ⁵⁴ is a linear or branched alkyl group having 1 to 6 carbon atoms, —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, a carboxy group, an acyl group having 1 to 6 carbon atoms, 6 represents an alkoxy group, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or an amino group. Linear or branched alkyl group having 1 to 6 carbon atoms, _-C as a substituent _(CF 3) 2 -OH, hydroxy group, a cyano group, a carboxy group, an acyl group having 1 to 6 carbon atoms, 1 to carbon atoms It may have at least one group selected from the group consisting of a carboxy group esterified with 6 alcohols and an amino group. When n54 is 2 or more, X ⁵⁴ may be a different group.
X ⁵⁴ is preferably —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, or a methoxy group from the viewpoint of good resist pattern shape.

Formula (5-5):
R ⁵⁵ represents a hydrogen atom or a methyl group.
R ⁵⁰⁴ and R ⁵⁰⁵ each represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and are preferably a methyl group, an ethyl group, or an isopropyl group from the viewpoint of sensitivity and resolution.

n55 represents an integer of 1 to 4, and 1 is preferable from the viewpoint of high dry etching resistance.
X ⁵⁵ represents a linear or branched alkyl group having 1 to 6 carbon _{atoms, -C (CF 3) 2 -OH} , hydroxy group, a cyano group, a carboxy group, an acyl group having 1 to 6 carbon atoms, 1 to carbon atoms 6 represents an alkoxy group, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or an amino group. Linear or branched alkyl group having 1 to 6 carbon atoms, _-C as a substituent _(CF 3) 2 -OH, hydroxy group, a cyano group, a carboxy group, an acyl group having 1 to 6 carbon atoms, 1 to carbon atoms It may have at least one group selected from the group consisting of a carboxy group esterified with 6 alcohols and an amino group. When n55 is 2 or more, X ⁵⁵ may be a different group.
X ⁵⁵ is preferably —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, or a methoxy group from the viewpoint of good resist pattern shape.

Formula (5-6):
R ⁵⁶ represents a hydrogen atom or a methyl group.
R ⁵⁰⁶ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and is preferably a methyl group, an ethyl group, or an isopropyl group in terms of sensitivity and resolution, and in terms of high solubility in a resist solvent, Atoms are preferred.

q2 represents 0 or 1, preferably 1 from the viewpoint of high dry etching resistance, and preferably 0 from the viewpoint of high solubility in a resist solvent.
R ⁵³⁵ and R ⁵³⁶ each represent a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, and from the viewpoint of high solubility in a resist solvent, a hydrogen atom, a methyl group, an ethyl group, or isopropyl Groups are preferred.
W ³ represents —O—, —S—, —NH— or a methylene chain [— (CH ₂ ) _{u 3} — (u 3 represents an integer of 1 to 6)], and has a high dry etching resistance, -CH ₂ - or _-CH 2 CH ₂ - is preferred.

n56 represents an integer of 1 to 4, and 1 is preferable from the viewpoint of high dry etching resistance.
X ⁵⁶ is a linear or branched alkyl group having 1 to 6 carbon atoms, —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, a carboxy group, an acyl group having 1 to 6 carbon atoms, 6 represents an alkoxy group, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or an amino group. Linear or branched alkyl group having 1 to 6 carbon atoms, _-C as a substituent _(CF 3) 2 -OH, hydroxy group, a cyano group, a carboxy group, an acyl group having 1 to 6 carbon atoms, 1 to carbon atoms It may have at least one group selected from the group consisting of a carboxy group and an amino group esterified with 6 alcohols. When n56 is 2 or more, X ⁵⁶ may be a different group.
X ⁵⁶ is preferably —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, or a methoxy group from the viewpoint of good resist pattern shape.

Formula (5-7):
R ⁵⁷ represents a hydrogen atom or a methyl group.
R ⁵⁷¹ and R ⁵⁷² represent the following (i) or (ii).
(I) R ⁵⁷¹ is a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, a bridged cyclic hydrocarbon group having 4 to 16 carbon atoms, or a bridged cyclic carbon group having 4 to 16 carbon atoms. Represents a linear or branched alkyl group having 1 to 6 carbon atoms and having a hydrogen group,
R ⁵⁷² represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms.
(Ii) R ⁵⁷¹ and R ⁵⁷² are bonded to each other to form a bridged cyclic hydrocarbon group having 4 to 16 carbon atoms together with the carbon atom to which each is bonded.
A linear or branched alkyl group having 1 to 6 carbon atoms has a hydroxy group, a carboxy group, an acyl group having 2 to 6 carbon atoms, or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms as a substituent. You may do it.
The bridged cyclic hydrocarbon group may have a linear or branched alkyl group having 1 to 6 carbon atoms as a substituent. The alkyl group may have a hydroxy group, a carboxy group, an acyl group having 2 to 6 carbon atoms, or a carboxy group esterified with an alcohol having 1 to 6 carbon atoms as a substituent.

As R ⁵⁷¹ and R ⁵⁷² , in terms of high dry etching resistance, R ⁵⁷¹ and R ⁵⁷² are bonded to each other, and together with the carbon atoms to which each is bonded, a bridged cyclic hydrocarbon group having 4 to 16 carbon atoms. The structure which forms is preferable.
R ⁵⁷¹ and R ⁵⁷² are included in the bridged cyclic hydrocarbon group formed together with the carbon atom to which R ⁵⁷¹ and R ⁵⁷² are bonded together in terms of excellent heat resistance and stability. It is preferable that the ring to be selected is a camphor ring, an adamantane ring, a norbornane ring, a pinane ring, a bicyclo [2.2.2] octane ring, a tetracyclododecane ring, a tricyclodecane ring, or a decahydronaphthalene ring.

X ⁵⁷ is a linear or branched alkyl group having 1 to 6 carbon atoms, —C (CF ₃ ) ₂ —OH, a hydroxy group, a cyano group, a carboxy group, an acyl group having 1 to 6 carbon atoms, 6 represents an alkoxy group, a carboxy group esterified with an alcohol having 1 to 6 carbon atoms, or an amino group. Linear or branched alkyl group having 1 to 6 carbon atoms, _-C as a substituent _(CF 3) 2 -OH, hydroxy group, a cyano group, a carboxy group, an acyl group having 1 to 6 carbon atoms, 1 to carbon atoms It may have at least one group selected from the group consisting of a carboxy group esterified with 6 alcohols and an amino group.
X ⁵⁷ is preferably —CH ₂ —C (CF ₃ ) ₂ —OH, —CH ₂ —OH, —CH ₂ —CN, —CH ₂ —O—CH ₃ , or - is _{(CH 2) 2 -O-CH} 3 preferred.

In the formulas (5-1) to (5-7), the position where X ⁵¹ , X ⁵² , X ⁵³ , X ⁵⁴ , X ⁵⁵ , X ⁵⁶ and X ⁵⁷ are bonded may be any position in the cyclic structure. .

The polymer having the structural unit (D) can be produced by polymerizing a monomer containing the monomer (d) that gives the structural unit (D).
Examples of the monomer (d) include monomers represented by the following formulas (13-1) to (13-79). In formulas (13-1) to (13-79), R represents a hydrogen atom or a methyl group.

In addition to the above monomers, unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid, itaconic acid and the like can be mentioned.
Among these, in terms of good solubility in a resist solvent, the formulas (13-1) to (13-9), the formulas (13-13) to (13-16), and the formulas (13-21) to (13-24), Formulas (13-30) to (13-34), Formulas (13-37) to (13-43), Formulas (13-56) to (13-59), Formula (13-62) ) To (13-63), formulas (13-66) to (13-69), formula (13-72), monomers represented by formulas (13-76) to (13-79), and these The geometric isomers and optical isomers are preferred.

  Moreover, in the point with high dry etching tolerance, Formula (13-25)-(13-30), Formula (13-44)-(13-55), Formula (13-60)-(13-61), Formula Monomers represented by (13-64) to (13-65), formula (13-71), formulas (13-73) to (13-75), and geometric isomers and optical isomers thereof. preferable.

(Structural unit (E))
The resist polymer of the present invention may have other structural units (E) excluding the structural units (A1), (A2), and (B) to (D) as necessary.
The proportion of the structural unit (E) is preferably 20 mol% or less in the structural unit (100 mol%) of the resist polymer.
Examples of the structural unit (E) include the following structural units (E1) and (E2).

(Structural unit (E1))
The structural unit (E1) is a structural unit having an alicyclic skeleton (nonpolar alicyclic skeleton) that does not have an acid leaving group and a hydrophilic group.
An alicyclic skeleton is a skeleton having one or more cyclic saturated hydrocarbon groups.

The structural unit (E1) tends to exhibit an effect of developing dry etching resistance.
The resist polymer of the present invention may have two or more different types of structural units (E1).
As the structural unit (E1), structural units represented by the following formulas (11-1) to (11-4) are preferable from the viewpoint of high dry etching resistance.

Formula (11-1):
R ³⁰¹ represents a hydrogen atom or a methyl group.
n301 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ³⁰¹ represents a linear or branched alkyl group having 1 to 6 carbon atoms. When n301 is 2 or more, X ³⁰¹ may be a different group.

Formula (11-2):
R ³⁰² represents a hydrogen atom or a methyl group.
n302 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ³⁰² represents a linear or branched alkyl group having 1 to 6 carbon atoms. When n302 is 2 or more, X ³⁰² may be a different group.

Formula (11-3):
R ³⁰³ represents a hydrogen atom or a methyl group.
n303 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ³⁰³ represents a linear or branched alkyl group having 1 to 6 carbon atoms. If n303 is 2 or ^{more, X 303} may be a different group.
p represents an integer of 0 to 2, and 0 is preferable in terms of high solubility in a resist solvent, and 1 is preferable in terms of high dry etching resistance.

Formula (11-4):
R ³⁰⁴ represents a hydrogen atom or a methyl group.
n304 represents an integer of 0 to 4, and 0 is preferable from the viewpoint of high dry etching resistance.
X ³⁰⁴ represents a linear or branched alkyl group having 1 to 6 carbon atoms. When n304 is 2 or more, X ³⁰⁴ may be a different group.
p1 represents an integer of 0 to 2, and 0 is preferable in terms of high solubility in a resist solvent, and 1 is preferable in terms of high dry etching resistance.

In the formulas (11-1) to (11-4), the position where X ³⁰¹ , X ³⁰² , X ³⁰³ and X ³⁰⁴ are bonded may be any position in the cyclic structure.

The polymer having the structural unit (E1) can be produced by polymerizing a monomer containing the monomer (e1) having a nonpolar alicyclic skeleton.
Examples of the monomer (e1) include cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, norbornyl (meth) acrylate, adamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, ( Examples include (meth) acrylic acid dicyclopentadienyl and derivatives having a linear or branched alkyl group having 1 to 6 carbon atoms on the alicyclic skeleton of these compounds.
Specific examples include monomers represented by the following formulas (14-1) to (14-5). In formulas (14-1) to (14-5), R represents a hydrogen atom or a methyl group.
In addition to the above monomers, those having a cycloolefin structure such as norbornene as the alicyclic skeleton can be mentioned.

(Structural unit (E2))
The structural unit (E2) is another structural unit (E) excluding the structural unit (E1).
The polymer having the structural unit (E2) can be produced by polymerizing the monomer including the monomer (e2).

Examples of the monomer (e2) include the following compounds.
(Meth) acrylic acid ester having a linear or branched structure: methyl (meth) acrylate, ethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-propyl (meth) acrylate, (meth) acrylic Isopropyl acid, butyl (meth) acrylate, isobutyl (meth) acrylate, n-propoxyethyl (meth) acrylate, isopropoxyethyl (meth) acrylate, n-butoxyethyl (meth) acrylate, (meth) acrylic Isobutoxyethyl acid, tert-butoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxy-n-propyl (meth) acrylate, (meta ) 4-hydroxy-n-butyl acrylate, 2-methacrylic acid (meth) acrylate Xylethyl, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoro-n-propyl (meth) acrylate, 2,2,3,3 (meth) acrylic acid 3-pentafluoro-n-propyl, methyl α- (tri) fluoromethyl acrylate, ethyl α- (tri) fluoromethyl acrylate, 2-ethylhexyl α- (tri) fluoromethyl acrylate, α- (tri) fluoro N-propyl methyl acrylate, isopropyl α- (tri) fluoromethyl acrylate, n-butyl α- (tri) fluoromethyl acrylate, isobutyl α- (tri) fluoromethyl acrylate, α- (tri) fluoromethyl acrylic Tert-butyl acid, α- (tri) fluoromethylacrylic acid methoxymethyl, α- (tri) fluoromethylacrylic acid Ethoxyethyl oxalate, n-propoxyethyl α- (tri) fluoromethyl acrylate, isopropoxyethyl α- (tri) fluoromethyl acrylate, n-butoxyethyl α- (tri) fluoromethyl acrylate, α- (tri ) Isobutoxyethyl fluoromethyl acrylate, tert-butoxyethyl α- (tri) fluoromethyl acrylate, and the like.

Aromatic alkenyl compounds: styrene, α-methylstyrene, vinyltoluene, p-hydroxystyrene, p-tert-butoxycarbonylhydroxystyrene, 3,5-di-tert-butyl-4-hydroxystyrene, 3,5-dimethyl- 4-hydroxystyrene, p-tert-perfluorobutylstyrene, p- (2-hydroxy-isopropyl) styrene and the like.
Carboxylic anhydride: maleic anhydride, itaconic anhydride, etc.
Other monomers: ethylene, propylene, norbornene, tetrafluoroethylene, acrylamide, N-methylacrylamide, N, N-dimethylacrylamide, vinyl chloride, vinyl fluoride, vinylidene fluoride, vinylpyrrolidone and the like.

(Resist polymer)
The weight average molecular weight of the resist polymer of the present invention is preferably 2,000 or more, more preferably 3,000 or more, further preferably 4,000 or more, from the viewpoint of dry etching resistance and resist pattern shape, and 5,000. The above is particularly preferable.
The weight average molecular weight of the resist polymer of the present invention is preferably 100,000 or less, more preferably 50,000 or less, even more preferably 30,000 or less, from the viewpoint of solubility in a resist solvent and resolution. 000 or less is particularly preferable.

  The molecular weight distribution of the resist polymer of the present invention is preferably 2.5 or less, more preferably 2.0 or less, and particularly preferably 1.8 or less, from the viewpoints of solubility in a resist solvent and resolution.

  The resist polymer of the present invention may be used alone or in combination of two or more.

  The resist polymer of the present invention may be used as a resist composition for metal etching, photofabrication, plate making, hologram, color filter, retardation film and the like in addition to semiconductor element production. .

(Method for producing resist polymer)
The resist polymer of the present invention is produced by a solution polymerization method.
The solution polymerization method may be a batch polymerization method in which monomers are charged in a polymerization vessel at once, or may be a dropping polymerization method in which a monomer is dropped into a polymerization vessel. Of these, the drop polymerization method is preferred because a polymer having a narrow composition distribution and / or molecular weight distribution can be obtained easily.

In the dropping polymerization method, the inside of the polymerization vessel is heated to a predetermined polymerization temperature, and then the monomer and the polymerization initiator are dropped into the polymerization vessel independently or in any combination.
The monomer may be dropped only with the monomer, or may be dropped as a monomer solution in which the monomer is dissolved in an organic solvent (hereinafter also referred to as “dropping solvent”).

  An organic solvent (hereinafter also referred to as “charged solvent”) may be charged into the polymerization vessel in advance, or the charged solvent may not be charged into the polymerization vessel in advance. When the charged solvent is not charged in the polymerization vessel in advance, the monomer or the polymerization initiator is dropped into the polymerization vessel in the absence of the charged solvent.

The polymerization initiator may be dissolved directly in the monomer, may be dissolved in the monomer solution, or may be dissolved only in the dropping solvent.
The monomer and the polymerization initiator may be dropped into the polymerization vessel after mixing in the same storage tank; they may be dropped into the polymerization container from each independent storage tank; They may be mixed immediately before the supply and dropped into the polymerization vessel.
One of the monomer and the polymerization initiator may be dropped first, and then the other may be dropped with a delay, or both may be dropped at the same timing.

The dropping rate may be constant until the end of dropping, or may be changed in multiple stages according to the consumption rate of the monomer or the polymerization initiator.
The dripping may be performed continuously or intermittently.
The polymerization temperature is preferably 50 to 150 ° C.

Examples of the organic solvent include the following compounds.
Ethers: chain ethers such as diethyl ether and propylene glycol monomethyl ether (hereinafter referred to as “PGME”); cyclic ethers such as tetrahydrofuran (hereinafter referred to as “THF”), 1,4-dioxane and the like.
Esters: methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate, propylene glycol monomethyl ether acetate (hereinafter referred to as “PGMEA”) and the like.
Ketones: acetone, methyl ethyl ketone (hereinafter referred to as “MEK”), methyl isobutyl ketone (hereinafter referred to as “MIBK”), and the like.
Amides: N, N-dimethylacetamide, N, N-dimethylformamide and the like.
Sulfoxide: dimethyl sulfoxide and the like.
Aromatic hydrocarbons: benzene, toluene, xylene and the like.
Aliphatic hydrocarbon: hexane and the like.
Alicyclic hydrocarbons: cyclohexane and the like.
Other: γ-butyrolactone and the like.

Among the above organic solvents, when a low molecular weight polymer is obtained, a hydroxyl group-containing ester such as ethyl lactate is preferable.
An organic solvent may be used individually by 1 type, and may use 2 or more types together.

When using 2 or more types of organic solvents together, the mixing ratio of the organic solvent in a dripping solvent and a preparation solvent can be set in arbitrary ratios.
As for the quantity of an organic solvent, 30-700 mass parts is preferable with respect to 100 mass parts of monomer whole quantity.
As for the quantity of a preparation solvent, 30-700 mass parts is preferable with respect to 100 mass parts of monomer whole quantity.
As for the density | concentration of a monomer, 5-50 mass% is preferable in a monomer solution (100 mass%).

As the polymerization initiator, those that generate radicals efficiently by heat are preferable. Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile, dimethyl-2,2′-azobisisobutyrate (hereinafter referred to as “DAIB”), 2,2′-azobis [ Azo compounds such as 2- (2-imidazolin-2-yl) propane]; 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexane, di (4-tert-butylcyclohexyl) peroxydi Examples thereof include organic peroxides such as carbonate.
Of the above polymerization initiators, DAIB is preferred from the viewpoint of the sensitivity of the resist composition.

  ArF excimer laser (wavelength: 193 nm) When producing a resist polymer used in lithography, as a polymerization initiator, the light transmittance of the resist polymer (transmittance with respect to light with a wavelength of 193 nm) is not reduced as much as possible. Those having no aromatic ring in the molecular structure are preferred. In consideration of safety during polymerization, the polymerization initiator preferably has a 10-hour half-life temperature of 60 ° C. or higher.

  The amount of the polymerization initiator is preferably 0.3 mol parts or more, more preferably 1 mol parts or more, and the molecular weight distribution is narrow with respect to 100 mol parts of the total monomer amount from the viewpoint of increasing the yield of the polymer. From the point of making it, 30 mol part or less is preferable with respect to 100 mol part of monomer whole quantity.

  When producing the resist polymer of the present invention, a chain transfer agent may be used as long as the storage stability of the resist composition is not impaired. Examples of the chain transfer agent include 1-butanethiol, 2-butanethiol, 1-octanethiol, 1-decanethiol, 1-tetradecanethiol, cyclohexanethiol, 2-methyl-1-propanethiol, 2-hydroxyethyl mercaptan. Etc.

  ArF excimer laser (wavelength: 193 nm) When producing a resist polymer used in lithography, as a chain transfer agent, the light transmittance of the resist polymer (transmittance with respect to light with a wavelength of 193 nm) is not reduced as much as possible. Those having no aromatic ring are preferred.

  The polymer solution obtained by the solution polymerization method was diluted to an appropriate solution viscosity with a good solvent such as 1,4-dioxane, acetone, THF, MEK, MIBK, γ-butyrolactone, PGMEA, and PGME as necessary. Then, it is dripped in a lot of poor solvents, such as methanol, water, hexane, and heptane, and a polymer is deposited. This process is called reprecipitation and is very effective for removing unreacted monomers, polymerization initiators and the like remaining in the polymer solution. If these unreacted substances remain as they are, there is a possibility that the performance of the resist film may be adversely affected. The reprecipitation process may be unnecessary depending on circumstances.

Thereafter, the precipitate is filtered off and sufficiently dried to obtain the resist polymer of the present invention. Moreover, after filtering off, you may use it as a wet powder, without drying.
The polymer solution may be used as it is as a resist composition, or the polymer solution may be diluted with an appropriate solvent and used as a resist composition, or the polymer solution may be concentrated and used as a resist composition. Good. At that time, additives such as a storage stabilizer may be appropriately added.

<Resist composition>
The resist composition of the present invention is obtained by dissolving the resist polymer of the present invention in a solvent. When the resist composition of the present invention is used as a chemically amplified resist composition, a photoacid generator is further dissolved.

(solvent)
Examples of the solvent include the following compounds.
Ketones: linear or branched ketones such as MEK, MIBK, 2-pentanone and 2-hexanone; cyclic ketones such as cyclopentanone and cyclohexanone.
Propylene glycol monoalkyl acetates: PGMEA, propylene glycol monoethyl ether acetate and the like.
Ethylene glycol monoalkyl ether acetates: ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate and the like.
Propylene glycol monoalkyl ethers: PGME, propylene glycol monoethyl ether, etc.
Ethylene glycol monoalkyl ethers: ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and the like.
Diethylene glycol alkyl ethers: diethylene glycol dimethyl ether, diethylene glycol monomethyl ether and the like.
Esters: ethyl acetate, ethyl lactate and the like.
Alcohols: n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, cyclohexanol, 1-octanol and the like.
Other: 1,4-dioxane, ethylene carbonate, γ-butyrolactone and the like.

A solvent may be used individually by 1 type and may use 2 or more types together.
The amount of the solvent is preferably 200 to 5000 parts by mass, and more preferably 300 to 2000 parts by mass with respect to 100 parts by mass of the resist polymer.

(Photoacid generator)
The photoacid generator can be arbitrarily selected from those that can be used as the photoacid generator of the chemically amplified resist composition. A photo-acid generator may be used individually by 1 type, and may use 2 or more types together.

Examples of the photoacid generator include onium salt compounds, sulfonimide compounds, sulfone compounds, sulfonic acid ester compounds, quinone diazide compounds, diazomethane compounds, and the like.
The photoacid generator is preferably an onium salt compound such as a sulfonium salt, iodonium salt, phosphonium salt, diazonium salt, pyridinium salt, specifically, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, triphenyl. Sulfonium naphthalenesulfonate, (hydroxyphenyl) benzylmethylsulfonium toluenesulfonate, diphenyliodonium triflate, diphenyliodonium pyrenesulfonate, diphenyliodonium dodecylbenzenesulfonate, diphenyliodonium hexafluoroantimonate, p-methylphenyldiphenylsulfonium nonafluorobutanesulfonate, tri ( tert-butylphenyl) sulfonium trifluorometa Sulfonate, and the like.

The amount of the photoacid generator is preferably 0.1 parts by mass or more and more preferably 0.5 parts by mass or more with respect to 100 parts by mass of the resist polymer. By setting the amount of the photoacid generator within this range, a chemical reaction due to the catalytic action of the acid generated by light irradiation can be sufficiently caused.
The amount of the photoacid generator is preferably 20 parts by mass or less and more preferably 10 parts by mass or less with respect to 100 parts by mass of the resist polymer. By setting the amount of the photoacid generator within this range, the stability of the resist composition is improved, and the occurrence of uneven coating during application of the resist composition, scum during development, etc. can be sufficiently suppressed.

(Nitrogen-containing compounds)
The chemically amplified resist composition may contain a nitrogen-containing compound. By including the nitrogen-containing compound, the resist pattern shape, the stability over time, and the like are further improved. That is, the cross-sectional shape of the resist pattern becomes closer to a rectangle, and the resist film is irradiated with light, then baked (PEB), and then left for several hours before the next development process. Although it is a line, the occurrence of the deterioration of the cross-sectional shape of the resist pattern is further suppressed when left as such (timed).

Examples of the nitrogen-containing compound include known compounds, and amines are preferable, and secondary lower aliphatic amines and tertiary lower aliphatic amines are more preferable.
The lower aliphatic amine is an alkyl or alkyl alcohol amine having 5 or less carbon atoms.

  Examples of the secondary lower aliphatic amine and tertiary lower aliphatic amine include trimethylamine, diethylamine, triethylamine, di-n-propylamine, tri-n-propylamine, tripentylamine, diethanolamine, triethanolamine and the like. And tertiary alkanolamines such as triethanolamine are preferred.

A nitrogen-containing compound may be used individually by 1 type, and may use 2 or more types together.
The amount of the nitrogen-containing compound is preferably 0.01 parts by mass or more with respect to 100 parts by mass of the resist polymer. By making the amount of the nitrogen-containing compound within this range, the resist pattern shape can be made more rectangular.
The amount of the nitrogen-containing compound is preferably 2 parts by mass or less with respect to 100 parts by mass of the resist polymer. By making the amount of the nitrogen-containing compound within this range, deterioration in sensitivity can be reduced.

(Organic carboxylic acid, phosphorus oxo acid or its derivative)
The chemically amplified resist composition may contain an organic carboxylic acid, an oxo acid of phosphorus, or a derivative thereof (hereinafter collectively referred to as an acid compound). By including an acid compound, it is possible to suppress deterioration in sensitivity due to the blending of the nitrogen-containing compound, and further improve the resist pattern shape, stability with time of leaving, and the like.

  Examples of the organic carboxylic acid include malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid, and the like.

Examples of phosphorus oxo acids or derivatives thereof include the following compounds.
Phosphoric acid or derivatives thereof: phosphoric acid, phosphoric acid di-n-butyl ester, phosphoric acid diphenyl ester and the like.
Phosphonic acid or derivatives thereof: phosphonic acid, phosphonic acid dimethyl ester, phosphonic acid di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, phosphonic acid dibenzyl ester, and the like.
Phosphinic acid or derivatives thereof: phosphinic acid, phenylphosphinic acid and the like.

As the phosphorus oxo acid or derivative thereof, phosphonic acid is preferred.
An acid compound may be used individually by 1 type, and may use 2 or more types together.
The amount of the acid compound is preferably 0.01 parts by mass or more with respect to 100 parts by mass of the resist polymer. By making the amount of the acid compound within this range, the resist pattern shape can be made more rectangular.
The amount of the acid compound is preferably 5 parts by mass or less with respect to 100 parts by mass of the resist polymer. By reducing the amount of the acid compound within this range, the film loss of the resist pattern can be reduced.

  The chemically amplified resist composition may contain both a nitrogen-containing compound and an acid compound, or may contain only one of them.

(Additive)
The resist composition of the present invention may contain various additives such as surfactants, other quenchers, sensitizers, antihalation agents, storage stabilizers, and antifoaming agents as necessary. Any of these additives can be used as long as they are known in the art. Further, the amount of these additives is not particularly limited, and may be determined as appropriate.

<Manufacturing method of substrate on which fine pattern is formed>
An example of the manufacturing method of the board | substrate with which the fine pattern was formed of this invention is demonstrated.
First, the resist composition of the present invention is applied to the surface of a substrate to be processed such as a silicon wafer on which a desired fine pattern is to be formed by spin coating or the like. And the resist film is formed on a board | substrate by drying the to-be-processed board | substrate with which this resist composition was apply | coated by baking process (prebaking) etc.

Next, the resist film is irradiated with light of 250 nm or less through a photomask to form a latent image (exposure). As irradiation light, a KrF excimer laser, an ArF excimer laser, an F ₂ excimer laser, and an EUV excimer laser are preferable, and an ArF excimer laser is particularly preferable. Moreover, you may irradiate an electron beam.
In addition, high-refractive-index liquids such as pure water, perfluoro-2-butyltetrahydrofuran, perfluorotrialkylamine, perhydronaphthalene, and perhydropyrene are interposed between the resist film and the final lens of the exposure apparatus. You may perform immersion exposure which irradiates light in a state.

After the exposure, heat treatment is appropriately performed (post-exposure baking, PEB), an alkali developer is brought into contact with the resist film, and the exposed portion is dissolved in the developer and removed (development). Examples of the alkaline developer include known ones.
After development, the substrate is appropriately rinsed with pure water or the like. In this way, a resist pattern is formed on the substrate to be processed.

The substrate on which the resist pattern is formed is appropriately heat-treated (post-baked) to strengthen the resist and selectively etch the portion without the resist.
After the etching, the resist is removed with a release agent to obtain a substrate on which a fine pattern is formed.

  Since the resist polymer of the present invention described above has the structural unit (A1), the resist film containing the polymer has high sensitivity and high resolution, a wide focal depth margin, and a high light transmittance. There are few defects at the time of development, and it has a dry etching resistance that can withstand the thinning of the resist film.

  In addition, since the resist composition of the present invention described above includes the resist polymer of the present invention, it has high sensitivity and high resolution, wide focus depth margin, and high light transmittance in DUV excimer laser lithography and the like. It is possible to form a resist film having dry etching resistance that can withstand thinning of the resist film with few defects during development.

  When the resist composition of the present invention is used as a resist composition for immersion, a resist pattern can be formed with high resolution. Therefore, the resist composition of the present invention can be suitably used for DUV excimer laser lithography, these immersion lithography and electron beam lithography, particularly ArF excimer laser lithography and immersion lithography.

  Moreover, in the manufacturing method of the board | substrate with which the fine pattern was formed of this invention demonstrated above, since the resist composition of this invention is used, the board | substrate with which the highly accurate fine pattern was formed can be manufactured.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.
“Parts” in the examples refers to “parts by mass” unless otherwise specified.

<Evaluation of resist polymer>
(Percentage of each structural unit)
The proportion of the respective structural units resist polymer is ¹ determined by ^{1 H-NMR} measurement in the case where it can be determined by ^H-NMR measurement, if it can not be determined in ^{1 H-NMR} measurement by such overlapping proton peak Was determined by ¹³ C-NMR measurement.

The measurement of ¹ H-NMR was performed using JNM-GX270 type FT-NMR (trade name) manufactured by JEOL Ltd., and a solution of a polymer sample for resist of about 5% by mass (deuterated chloroform solution or deuterated). Dimethyl sulfoxide solution) was put in a test tube having a diameter of 5 mmφ, and the measurement was carried out 64 times in an observation frequency of 270 MHz and a single pulse mode. The measurement temperature was 40 ° C. when deuterated chloroform was used as the solvent, and 60 ° C. when deuterated dimethyl sulfoxide was used as the solvent.

^In the case of ¹³ C-NMR measurement, using a UNITY-INOVA type FT-NMR (trade name) manufactured by Varian Technologies, an approximately 20% by mass resist polymer sample solution of deuterated dimethyl sulfoxide has a diameter of 5 mmφ. The sample was subjected to a total of 50000 times by the proton complete decoupling method in which the measurement temperature was 60 ° C., the observation frequency was 125 MHz, and the nuclear overhauser effect (NOE) was removed.

(Mass average molecular weight, molecular weight distribution)
About 20 mg of the resist polymer is dissolved in 5 mL of THF and filtered through a 0.5 μm membrane filter to prepare a sample solution. The sample solution is manufactured by Tosoh Corporation using gel permeation chromatography (GPC). Then, the mass average molecular weight (Mw) and the number average molecular weight (Mn) of the resist polymer were measured. The measurement was performed using Showa Denko Co., Ltd., Shodex GPC K-805L (trade name) in series as a separation column, THF (flow rate: 1.0 mL / min) as a solvent, and differential as a detector. Using a refractometer, polystyrene was used as the standard polymer, and the measurement was performed at a temperature of 40 ° C. and an injection amount of 0.1 mL.
The molecular weight distribution was Mw / Mn.

<Evaluation of resist composition>
(Light transmittance)
A resist solution was prepared by mixing 5 parts of a resist polymer and 45 parts of PGMEA as a solvent to obtain a uniform solution, followed by filtration through a membrane filter having a pore size of 0.1 μm.
The resist composition was spin-coated on a quartz wafer and prebaked at 120 ° C. for 60 seconds using a hot plate to form a resist film having a thickness of 1 μm.
A resist film is placed on the sample side, and an untreated quartz wafer is placed on the reference side, and a wavelength range of 192 to 194 nm is scanned using an ultraviolet / visible absorptiometer UV-3100 (trade name) manufactured by Shimadzu Corporation. Measurement was performed by setting the medium speed, the sampling pitch automatically, and the slit width 2.0, and the light transmittance at 193 nm was obtained.

(Preparation of chemically amplified resist composition)
100 parts of a resist polymer, 2 parts of triphenylsulfonium triflate as a photoacid generator, 720 parts of PGMEA as a solvent and 180 parts of ethyl lactate are mixed to form a uniform solution, and then filtered through a membrane filter having a pore size of 0.1 μm. Then, a chemically amplified resist composition was prepared.

(sensitivity)
A chemically amplified resist composition was spin-coated on a silicon wafer and pre-baked at 120 ° C. for 60 seconds using a hot plate to form a resist film having a thickness of 0.3 μm.
The resist film was exposed with an ArF excimer laser exposure machine (wavelength: 193 nm) using a line-and-space pattern mask, and then subjected to post-exposure baking at 110 ° C. for 60 seconds using a hot plate.
The resist film was developed at room temperature using a 2.38% tetramethylammonium hydroxide aqueous solution, washed with pure water, and dried to form a resist pattern.
At this time, the exposure amount (mJ / cm ² ) at which the mask pattern of 0.16 μm was transferred to the resist pattern line width of 0.16 μm was measured and used as sensitivity.

(resolution)
In addition, an exposure amount at which a mask pattern of 0.16 μm is transferred to a resist pattern line width of 0.16 μm is set as an optimal exposure amount, and the minimum dimension (μm) of the resist pattern formed by exposure with the exposure amount and development processing. ) As the resolution.

(Defect amount)
With respect to the resist pattern formed by exposure and development processing with the optimum exposure amount, the number of development defects was measured by using a surface defect observation apparatus KLA2132 (trade name) manufactured by KLA Tencor Co., Ltd., and used as a defect amount.

(Depth of focus)
Using a 0.16 μm line-and-space pattern, changing the depth of focus from -1.0 μm to +1.0 μm in 0.1 μm increments, exposing at the optimum exposure dose at each focal depth, and developing to form The resist pattern was observed using a JSM-6340F field emission scanning electron microscope (trade name) manufactured by JEOL.
The focus depth range (μm) in which the resist pattern line width is 0.144 μm (−10%) to 0.176 μm (+ 10%) was defined as the focus depth margin.

(Dry etching resistance)
A silicon wafer on which a resist film having a thickness of 0.3 μm was formed was subjected to dry etching using an SPE-220T type dry etching apparatus (trade name) manufactured by Showa Vacuum Co., Ltd. The processing conditions were such that the gas type and gas flow rate were CF ₄ / O ₂ = 95 sccm / 5.0 sccm, the processing chamber pressure was 15 Pa, the plasma power was 400 W, and the processing time was 2 minutes. The thickness of the resist film before and after the dry etching treatment was measured using a Lambda Ace VM-8000J type optical interference type film thickness measuring device (trade name) manufactured by Dainippon Screen Mfg. The measurement method was to measure the thickness of a total of five points including the center of the wafer and the points moved 25 mm up, down, left, and right from the center, and the average value was taken as the thickness of the resist film.

The dry etching resistance is the thickness (T) of the resist film before the dry etching process, the thickness (t) of the resist film after the dry etching process, and the thickness of the reference cresol novolac resin before the dry etching process (T ₀ ) and the thickness (t ₀ ) after the dry etching treatment, the value (ER) obtained by the following formula was used.
ER = (T−t) / (T ₀ −t ₀ )

[Example 1]
After putting 74.3 parts of ethyl lactate at room temperature in a flask equipped with a dropping device, a nitrogen inlet, a stirrer, a condenser, and a thermometer, nitrogen was blown into the ethyl lactate for 30 minutes using a ball filter. Thereafter, the flask was placed in a hot water bath, and the temperature of the hot water bath was raised to 80 ° C. while stirring the inside of the flask in a nitrogen atmosphere.
30.6 parts of α-methacryloyloxy-γ-butyrolactone represented by the following formula (51) (hereinafter referred to as “GBLMA”),
39.3 parts of 2-methacryloyloxy-2-methyladamantane (hereinafter referred to as “MAdMA”) represented by the following formula (52);
19.2 parts of 2-methacryloyloxymethyl-6- (ethylcyclopentyloxycarbonylmethyl) naphthalene (hereinafter referred to as “ECPNMA”) represented by the following formula (53);
A monomer solution was prepared by mixing 133.7 parts of ethyl lactate and 2.94 parts of DAIB. From the dropping device, the monomer solution was dropped into the flask at a constant rate over 4 hours. Then, the temperature of 80 degreeC was hold | maintained for 3 hours.

  The obtained reaction solution was added dropwise to about 10 times the amount of methanol with stirring to obtain a white precipitate (resist polymer A-1). The precipitate was filtered off and again poured into about 10 times the amount of methanol with respect to the reaction solution, and the precipitate was washed while stirring. The washed precipitate was filtered off and dried under reduced pressure at 60 ° C. for about 40 hours. The obtained resist polymer A-1 and the resist composition were evaluated. The results are shown in Table 1.

[Example 2]
Into a flask equipped with a dropping device, a nitrogen inlet, a stirrer, a condenser, and a thermometer, 83.8 parts of ethyl lactate was added at room temperature, and then nitrogen was blown into the ethyl lactate for 30 minutes using a ball filter. Thereafter, the flask was placed in a hot water bath, and the temperature of the hot water bath was raised to 80 ° C. while stirring the inside of the flask in a nitrogen atmosphere.
8- or 9-acryloyloxy-4-oxatricyclo [5.2.1.0 ^2,6 ] decan-3-one represented by the following formula (54) (hereinafter referred to as “OTDA”) 31 .1 part
45.0 parts of 2-adamantyloxymethyl methacrylate (hereinafter referred to as “AdOMMA”) represented by the following formula (55);
12.3 parts of 1-methacryloyloxy-3-hydroxyadamantane (hereinafter referred to as “HAdMA”) represented by the following formula (56);
12.3 parts of 2-methacryloyloxymethyl-6- (2-adamantyloxycarbonylmethyl) naphthalene (hereinafter referred to as “AdONMA”) represented by the following formula (57);
A monomer solution was prepared by mixing 150.9 parts of ethyl lactate and 8.92 parts of DAIB. From the dropping device, the monomer solution was dropped into the flask at a constant rate over 4 hours. Then, the temperature of 80 degreeC was hold | maintained for 3 hours.

  The obtained reaction solution was dropped into a mixed solvent of about 10 times the amount of methanol and water (methanol / water = 85/15 volume ratio) with stirring, and a white precipitate (resist polymer A-2) A precipitate was obtained. The precipitate was filtered off, and again poured into a mixed solvent of methanol and water (methanol / water = 95/5 volume ratio) of about 10 times the amount of the reaction solution, and the precipitate was washed with stirring. The washed precipitate was filtered off and dried under reduced pressure at 60 ° C. for about 40 hours. The obtained resist polymer A-2 and the resist composition were evaluated. The results are shown in Table 1.

Example 3
Into a flask equipped with a dropping device, a nitrogen inlet, a stirrer, a condenser, and a thermometer, 73.2 parts of ethyl lactate was added at room temperature, and then nitrogen was blown into the ethyl lactate for 30 minutes using a ball filter. Thereafter, the flask was placed in a hot water bath, and the temperature of the hot water bath was raised to 80 ° C. while stirring the inside of the flask in a nitrogen atmosphere.
19.7 parts of ethylcyclopentyl methacrylate represented by the following formula (58) (hereinafter referred to as “ECPMA”),
12.3 parts of 2- and 3-cyano-5-norbornyl methacrylate (hereinafter referred to as “CNNMA”) represented by the following formula (59);
15.8 parts of 2-methacryloyloxymethyl-6- (ethylnorbornyloxycarbonylmethyl) naphthalene (hereinafter referred to as “ENBNMA”) represented by the following formula (60);
7.4 parts of 2-methacryloyloxymethyl-6-hydroxynaphthalene (hereinafter referred to as “HNMMA”) represented by the following formula (61);
A monomer solution was prepared by mixing 27.2 parts of GBLMA, 112.5 parts of ethyl lactate and 1.38 parts of DAIB. From the dropping device, the monomer solution was dropped into the flask at a constant rate over 4 hours. Then, the temperature of 80 degreeC was hold | maintained for 3 hours.

  The obtained reaction solution was added dropwise to about 10 times amount of methanol with stirring to obtain a white precipitate (resist polymer A-3). The precipitate was filtered off and again poured into about 10 times the amount of methanol with respect to the reaction solution, and the precipitate was washed while stirring. The washed precipitate was filtered off and dried under reduced pressure at 60 ° C. for about 40 hours. The obtained resist polymer A-3 and the resist composition were evaluated. The results are shown in Table 1.

Example 4
Into a flask equipped with a dropping device, a nitrogen inlet, a stirrer, a condenser, and a thermometer, 72.4 parts of ethyl lactate was added at room temperature, and then nitrogen was blown into the ethyl lactate for 30 minutes using a ball filter. Thereafter, the flask was placed in a hot water bath, and the temperature of the hot water bath was raised to 80 ° C. while stirring the inside of the flask in a nitrogen atmosphere.
10.7 parts of 1-methacryloyloxymethyl-5- (ethylcyclohexyloxycarbonylmethyl) naphthalene (hereinafter referred to as “15EHNMA”) represented by the following formula (62);
A monomer solution was prepared by mixing 26.5 parts of GBLMA, 40.3 parts of MAdMA, 9.4 parts of HAdMA, 130.3 parts of ethyl lactate and 3.86 parts of DAIB. From the dropping device, the monomer solution was dropped into the flask at a constant rate over 4 hours. Then, the temperature of 80 degreeC was hold | maintained for 3 hours.

  The obtained reaction solution was added dropwise to about 10 times the amount of methanol with stirring to obtain a white precipitate (resist polymer A-4). The precipitate was filtered off and again poured into about 10 times the amount of methanol with respect to the reaction solution, and the precipitate was washed while stirring. The washed precipitate was filtered off and dried under reduced pressure at 60 ° C. for about 40 hours. The obtained resist polymer A-4 and the resist composition were evaluated. The results are shown in Table 1.

[Comparative Example 1]
After putting 69.6 parts of ethyl lactate at room temperature into a flask equipped with a dropping device, a nitrogen inlet, a stirrer, a condenser, and a thermometer, nitrogen was blown into the ethyl lactate for 30 minutes using a ball filter. Thereafter, the flask was placed in a hot water bath, and the temperature of the hot water bath was raised to 80 ° C. while stirring the inside of the flask in a nitrogen atmosphere.
A monomer solution was prepared by mixing 27.2 parts of GBLMA, 42.1 parts of MAdMA, 14.2 parts of HAdMA, 125.2 parts of ethyl lactate and 2.76 parts of DAIB. From the dropping device, the monomer solution was dropped into the flask at a constant rate over 4 hours. Then, the temperature of 80 degreeC was hold | maintained for 3 hours.

  The obtained reaction solution was dropped into a mixed solvent of about 10 times the amount of methanol and water (methanol / water = 80/20 volume ratio) with stirring, and a white precipitate (resist polymer B-1) A precipitate was obtained. The precipitate was filtered off, and again poured into a mixed solvent of methanol and water (methanol / water = 90/10 volume ratio) of about 10 times the amount of the reaction solution, and the precipitate was washed with stirring. The washed precipitate was filtered off and dried under reduced pressure at 60 ° C. for about 40 hours. The obtained resist polymer B-1 and the resist composition were evaluated. The results are shown in Table 1.

[Comparative Example 2]
Into a flask equipped with a dropping device, a nitrogen inlet, a stirrer, a condenser, and a thermometer, 69.5 parts of ethyl lactate was added at room temperature, and then nitrogen was blown into the ethyl lactate for 30 minutes using a ball filter. Thereafter, the flask was placed in a hot water bath, and the temperature of the hot water bath was raised to 80 ° C. while stirring the inside of the flask in a nitrogen atmosphere.
6.8 parts of 2-vinyl-6-hydroxynaphthalene (hereinafter referred to as “HVN”) represented by the following formula (63);
A monomer solution was prepared by mixing 27.2 parts of GBLMA, 37.4 parts of MAdMA, 9.4 parts of HAdMA, 125.0 parts of ethyl lactate and 2.76 parts of DAIB. From the dropping device, the monomer solution was dropped into the flask at a constant rate over 4 hours. Then, the temperature of 80 degreeC was hold | maintained for 3 hours.

  The obtained reaction solution was added dropwise to about 10 times the amount of methanol with stirring to obtain a white precipitate (resist polymer B-2). The precipitate was filtered off and again poured into about 10 times the amount of methanol with respect to the reaction solution, and the precipitate was washed while stirring. The washed precipitate was filtered off and dried under reduced pressure at 60 ° C. for about 40 hours. The obtained resist polymer B-2 and the resist composition were evaluated. The results are shown in Table 1.

The resist polymer of the present invention (Examples 1 to 4) does not have the structural unit (A1), but has a light beam at the exposure wavelength as compared with the resist polymer of Comparative Example 2 having the structural unit (A2). Excellent transmittance.
Furthermore, the resist composition (Examples 1 to 4) using the resist polymer of the present invention uses the resist polymer of Comparative Example 1 having neither the structural unit (A1) nor the structural unit (A2). Compared with the conventional resist composition, it had sufficient resolution, wide focus depth margin, few defects, and excellent dry etching resistance.
Moreover, the resist composition (Examples 1-4) using the resist polymer of this invention does not have a structural unit (A1), but the resist polymer of the comparative example 2 which has a structural unit (A2). Compared to the resist composition used, it had sufficient sensitivity and resolution, had a wide focal depth margin, and was excellent in dry etching resistance.

  The resist polymer and resist composition of the present invention are suitable for fine processing by excimer laser and electron beam lithography.

Claims (4)

A resist polymer having a structural unit (A1) represented by the following formula (1-1).

In formula (1-1),
R ¹⁰ represents a hydrogen atom or a methyl group,
G represents a single bond, —C (═O) —O—, —O—, or —O—C (═O) —,
L ¹ ′ represents a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms which may have a hetero atom,
X ¹¹ is an alkyl group having 1 to 6 carbon atoms, a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a carboxy esterified with an alcohol having 1 to 6 carbon atoms. Represents a group or an amino group, and the alkyl group having 1 to 6 carbon atoms of X ¹¹ is a hydroxy group, a carboxy group, an acyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a carbon number as a substituent. May have at least one group selected from the group consisting of a carboxyl group esterified with 1 to 6 alcohols, a cyano group and an amino group,
h11 is an integer of 0 to 4, when h11 is 2 or ^{more, X 11} may be a different group respectively,
g3 represents 0 or 1,
Y represents —C (R ¹²¹ ) (R ¹²² ) (R ¹²³ ), or —C (R ¹³¹ ) (R ¹³² ) —O—R ¹³³ ;
R ¹²¹ , R ¹²² , and R ¹²³ each represent (i) a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or an alkyl group having 1 to 4 carbon atoms, and R ¹²¹ , R ¹²² , At least one of R ¹²³ is the alicyclic hydrocarbon group or a derivative thereof, or (ii) any two of R ¹²¹ , R ¹²² , and R ¹²³ are bonded to each other, and each is bonded Together with the carbon atom, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, and the remaining one of R ¹²¹ , R ¹²² , and R ¹²³ is an alkyl group having 1 to 4 carbon atoms or A monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof,
R ¹³¹ , R ¹³² , and R ¹³³ represent (i) R ¹³³ represents a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or an alkyl group having 1 to 4 carbon atoms, and R ¹³¹ , R ¹³² each represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, or (ii) two of R ¹³¹ or R ¹³² and R ¹³³ are bonded to each other, and together with the carbon atom to which each is bonded, A divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof is formed, and the remaining one of R ¹³¹ and R ¹³² represents a hydrogen atom. The resist polymer according to claim 1, wherein the structural unit (A1) is a structural unit (A11) represented by the following formula (1-2).

In formula (1-2), R ¹⁰ , G, L ¹ ′, Y, and g3 are respectively synonymous with formula (1-1).   A resist composition comprising the resist polymer according to claim 1. Applying the resist composition according to claim 3 on a substrate to be processed to form a resist film;
Irradiating the resist film with light having a wavelength of 250 nm or less to form a latent image;
And a step of developing the resist film on which the latent image is formed with a developer.