JP6722433B2 - Method for forming resist pattern and polymer composition for thickening pattern - Google Patents

Description

The present invention relates to a resist pattern forming method and a polymer composition for thickening a pattern.

In the lithographic technique, for example, a resist film made of a resist material is formed on a substrate, and the resist film is selectively exposed to radiation such as light or an electron beam through a mask on which a predetermined pattern is formed. A step of forming a resist pattern having a predetermined shape on the resist film is performed by performing exposure and development processing.
A resist material in which the exposed portion changes to a characteristic that dissolves in a developing solution is called a positive type, and a resist material in which the exposed portion changes to a characteristic that does not dissolve in a developing solution is called a negative type.

In the manufacture of semiconductor devices and liquid crystal display devices, finer patterns are being advanced due to advances in lithography technology.
As a pattern miniaturization method, generally, the wavelength of an exposure light source is shortened (increased in energy). Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but nowadays, mass production of semiconductor elements using KrF excimer laser or ArF excimer laser is being carried out. Further, electron beams, EUV (extreme ultraviolet), X-rays, etc. having a shorter wavelength (high energy) than these excimer lasers are also being studied.

As the wavelength of the exposure light source is shortened, the resist material is required to have improved lithography properties such as sensitivity to the exposure light source and resolution capable of reproducing a fine pattern. A chemically amplified resist composition is known as a resist material satisfying such requirements.
As the chemically amplified resist composition, those containing a base material component whose solubility in a developing solution is changed by the action of an acid and an acid generator component which generates an acid upon exposure are generally used. There is. For example, when the developing solution is an alkaline developing solution (alkali developing process), a base component that increases the solubility in the alkaline developing solution by the action of acid is used.

A positive-type chemically amplified resist composition, that is, a positive-type development process in which a chemically-amplified resist composition whose solubility in an alkali developing solution increases by exposure and an alkali developing solution are combined is a negative-type chemically amplified resist composition. Compared with a negative development process in which a resist composition and an alkali developing solution are combined, there are advantages such that the structure of the photomask can be simplified and the characteristics of the formed pattern are excellent. Therefore, at present, a positive development process in which a positive chemically amplified resist composition is combined with an alkaline developer is mainly used for forming a fine pattern.

When the positive development process is applied, when a resist film obtained by coating a chemically amplified resist composition on a support is selectively exposed, the exposed part of the resist film is decomposed by acid decomposition in the base resin. The functional group is decomposed by the action of the acid generated from the acid generator, etc., and changes from poorly soluble to soluble in an alkali developing solution, while the unexposed portion of the resist film remains alkali poorly soluble, so that the alkali By developing with a developing solution, a dissolution contrast can be provided between the exposed area and the unexposed area, and a positive resist pattern can be formed.
However, when the positive development process is applied to form a fine pattern (dense pattern, trench pattern, etc.), a region having a low optical strength occurs in the exposed portion of the resist film, particularly in the film thickness direction. , The resolution of the resist pattern is likely to decrease.

A method of forming a resist pattern (negative resist pattern) by selectively dissolving and removing a region having weak optical intensity is useful for forming the fine pattern as described above. As a method of forming a negative resist pattern using a chemically amplified resist composition used in a mainstream positive development process, a negative development process in combination with a developer containing an organic solvent (organic developer) is used. Is known (for example, refer to Patent Document 1).
When the negative development process is applied, when a resist film obtained by applying a chemically amplified resist composition on a support is selectively exposed, the exposed part of the resist film is decomposed by acid decomposition in the base resin. The functional group is decomposed by the action of an acid generated from an acid generator, etc., and changes from soluble to poorly soluble in an organic developing solution, while the unexposed portion of the resist film remains soluble and remains organic. By developing with a developing solution, a dissolution contrast can be provided between the exposed portion and the unexposed portion, and a negative resist pattern in which the exposed portion remains as a pattern can be formed.

JP, 2013-178515, A

In recent years, further advances in lithography technology and expansion of application fields have led to rapid miniaturization of patterns. Among them, when manufacturing a semiconductor device or the like, a technique capable of forming a fine pattern having a dimension of less than 100 nm by a simple method is required.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a resist pattern forming method capable of forming a finer pattern by a simple method.

A first aspect of the present invention is a method for forming a resist pattern in which a resist prepattern is thickened, which comprises a step A of forming a resist prepattern on a support, and a step of coating the resist prepattern. A step B of applying a pattern thickening polymer composition to form a polymer film on a support having the resist prepattern formed thereon, and a step C of forming a developer insoluble layer on the surface of the resist prepattern. And a step D of developing the resist pre-pattern having the developer-insoluble layer formed on the surface and the polymer film covering the resist pre-pattern to form a resist pattern thickened from the resist pre-pattern. The method for forming a resist pattern is characterized in that the pattern thickening polymer composition contains a block copolymer containing a block chain (b1) having a function of thickening the resist pre-pattern.

A second aspect of the present invention is a pattern thickening polymer composition used for thickening a resist pre-pattern, comprising a block chain (b1) having a thickening function of the resist pre-pattern. A pattern thickening polymer composition comprising a block copolymer containing the same.

According to the present invention, it is possible to provide a resist pattern forming method capable of forming a finer pattern by a simple method.

It is a schematic process drawing explaining one embodiment of a resist pattern forming method.

In the present specification and claims, the term “aliphatic” is defined as a concept relative to aromatic and means a group, compound or the like having no aromaticity.
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups.
Unless otherwise specified, the "alkylene group" includes linear, branched and cyclic divalent saturated hydrocarbon groups. The same applies to the alkyl group in the alkoxy group.
The “halogenated alkyl group” is a group in which a part or all of hydrogen atoms of an alkyl group are substituted with a halogen atom, and the halogen atom includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
The “fluorinated alkyl group” or “fluorinated alkylene group” refers to a group in which part or all of the hydrogen atoms of the alkyl group or alkylene group are substituted with fluorine atoms.
The "structural unit" means a monomer unit (monomer unit) that constitutes a high molecular compound (resin, polymer, copolymer).
The “structural unit derived from an acrylate ester” means a constitutional unit formed by cleavage of an ethylenic double bond of an acrylate ester.
The “acrylic acid ester” is a compound in which a hydrogen atom at the carboxy group end of acrylic acid (CH ₂ ═CH—COOH) is substituted with an organic group.
In the acrylate ester, the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. The substituent (R ^α ) for substituting the hydrogen atom bonded to the carbon atom at the α-position is an atom or a group other than a hydrogen atom, and is, for example, an alkyl group having 1 to 5 carbon atoms or a halogenated group having 1 to 5 carbon atoms. Examples thereof include an alkyl group and a hydroxyalkyl group. The α-position carbon atom of an acrylate ester is a carbon atom to which a carbonyl group is bonded, unless otherwise specified.
Hereinafter, an acrylic acid ester in which a hydrogen atom bonded to a carbon atom at the α-position is substituted with a substituent may be referred to as an α-substituted acrylic acid ester. In addition, the acrylic ester and the α-substituted acrylic ester may be collectively referred to as “(α-substituted) acrylic ester”.
The “structural unit derived from hydroxystyrene or hydroxystyrene derivative” means a structural unit formed by cleavage of the ethylenic double bond of hydroxystyrene or hydroxystyrene derivative.
The “hydroxystyrene derivative” is a concept including hydroxystyrene in which the hydrogen atom at the α-position is substituted with another substituent such as an alkyl group and a halogenated alkyl group, and derivatives thereof. As those derivatives, those obtained by substituting the hydrogen atom of the hydroxyl group of hydroxystyrene with an organic group which may substitute the hydrogen atom at the α-position with an organic group, or even if the hydrogen atom at the α-position is substituted with a substituent Examples thereof include those in which a substituent other than a hydroxyl group is bonded to the benzene ring of good hydroxystyrene. The α-position (carbon atom at the α-position) refers to the carbon atom to which the benzene ring is bonded, unless otherwise specified.
Examples of the substituent for substituting the hydrogen atom at the α-position of hydroxystyrene include the same ones as the substituents at the α-position in the above α-substituted acrylate ester.
The “constituent unit derived from vinylbenzoic acid or a vinylbenzoic acid derivative” means a constituent unit formed by cleavage of the ethylenic double bond of vinylbenzoic acid or a vinylbenzoic acid derivative.
The term “vinyl benzoic acid derivative” includes vinyl benzoic acid in which the α-position hydrogen atom is substituted with another substituent such as an alkyl group and a halogenated alkyl group, and a derivative thereof. Those derivatives include those in which the hydrogen atom of the carboxy group of vinylbenzoic acid, which may have a hydrogen atom at the α-position substituted by an organic group, and the hydrogen atom at the α-position are substituted by a substituent. And the like. Examples thereof include vinyl benzoic acid having a benzene ring to which a substituent other than a hydroxyl group and a carboxy group is bonded. The α-position (carbon atom at the α-position) refers to the carbon atom to which the benzene ring is bonded, unless otherwise specified.
The “styrene derivative” means one in which the hydrogen atom at the α-position of styrene is substituted with another substituent such as an alkyl group or a halogenated alkyl group.
The "structural unit derived from styrene" and "structural unit derived from styrene derivative" mean a structural unit formed by cleavage of the ethylenic double bond of styrene or a styrene derivative.
The alkyl group as the α-position substituent is preferably a linear or branched alkyl group, specifically, an alkyl group having 1 to 5 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group , N-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group) and the like.
The halogenated alkyl group as the α-position substituent is specifically a group in which a part or all of the hydrogen atoms of the above-mentioned “alkyl group as the α-position substituent” is substituted with a halogen atom. To be Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is particularly preferable.
Specific examples of the hydroxyalkyl group as the α-position substituent include groups in which part or all of the hydrogen atoms of the above-mentioned “alkyl group as the α-position substituent” are substituted with hydroxyl groups. 1-5 are preferable and, as for the number of the hydroxyl groups in this hydroxyalkyl group, 1 is the most preferable.
Be referred to as a "may have a substituent", the case of replacing a hydrogen atom (-H) a monovalent group, methylene group - when substituting a divalent radical (-CH ₂₎ Including both.
“Exposure” is a concept that includes all radiation irradiation.

(Method of forming resist pattern)
The resist pattern forming method of the first aspect of the present invention is a method of forming a resist pattern in which a resist pre-pattern is thickened, and has the following steps A, B, C and D.
Step A: Step of forming a resist prepattern on a support Step B: Application of a polymer composition for pattern thickening on a support on which the resist prepattern is formed so as to cover the resist prepattern Step C: Step of forming a developer insoluble layer on the surface of the resist pre-pattern Step D: Resist pre-pattern having the developer insoluble layer formed on the surface and the polymer film coating the same To develop a resist pattern in which the resist pre-pattern is thickened

<Polymer composition for thickening pattern>
The pattern thickening polymer composition used in step B is used for thickening the resist pre-pattern formed in step A, and has a block chain having a thickening function of the resist pre-pattern. It contains a block copolymer containing (b1).

In the present invention, “thickening the resist pre-pattern” means changing the dimensions of the pattern previously formed (shrinking), and by thickening the pattern, for example, if it is a hole pattern, it is opened. The area of the hole is narrowed (the diameter of the hole is reduced); in the line and space pattern, the line width is widened and the space width is narrowed.
“Having the function of thickening the resist pre-pattern” means that it has a function of interacting with the resist pre-pattern and newly forming a part of the pattern (developer-insoluble layer) on the resist pre-pattern surface. means.

<< block copolymer >>
The block copolymer in the present invention contains a block chain (b1) having a function of thickening the resist prepattern.
The block copolymer refers to a polymer compound in which a plurality of partial structural components (block chains) in which structural units of the same type are repeatedly bonded are bonded. The types of block chains constituting the block copolymer may be two types or three or more types.

・Block chain (b1)
The block chain (b1) has a thickening function of the resist prepattern.
In the present invention, the block chain (b1) is a partial constituent component that interacts with the resist prepattern and is capable of forming a developer insoluble layer on the surface of the resist prepattern.

The block chain (b1) preferably has a neutralizing group. Since the block chain (b1) has a neutralizing group, in step C, the block chain (b1) and the resist prepattern are neutralized, and a developer insoluble layer is easily formed on the resist prepattern surface. Is formed.

In the present invention, the “neutralizing group” means a group capable of forming a developer insoluble layer on the surface of the resist prepattern by neutralizing the resist prepattern.
In step C, the neutralizing group contained in the block chain (b1) is neutralized with the carboxylic acid, hydroxyl group, lactone, acid anhydride or ester (hereinafter referred to as “carboxylic acid etc.”) on the surface of the resist prepattern. Thus, a developer insoluble layer is formed on the surface of the resist prepattern.
The neutralizing group contained in the block chain (b1) is appropriately selected in consideration of the type of resist prepattern formed in step A. For example, the step A is an operation of forming a resist film on a support using a resist composition containing a resin component whose solubility in an organic solvent is reduced by the action of an acid, and developing the resist film with an organic solvent. And the step of forming a resist pre-pattern, the neutralizing group contained in the block chain (b1) is a basic group.
As the basic group, an “organic group having a nitrogen atom” exemplified in the description of Rx ¹ in the general formula (b1-u1) described later is preferable.

The preferred block chain (b1) includes, for example, a partial structural component in which structural units represented by general formula (b1-u1) shown below are repeatedly bonded.

［式中、Ｒは、水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基である。Ｖｘ^０１は、エーテル結合若しくはアミド結合を有する２価の炭化水素基、２価の芳香族炭化水素基又は単結合である。Ｙｘ^０１は、単結合又は２価の連結基である。Ｒｘ^１は、中和性基を含む有機基である。］

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Vx ⁰¹ is a divalent hydrocarbon group having an ether bond or an amide bond, a divalent aromatic hydrocarbon group, or a single bond. Yx ⁰¹ is a single bond or a divalent linking group. Rx ¹ is an organic group containing a neutralizing group. ]

[R]
In the formula (b1-u1), R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms.
The alkyl group having 1 to 5 carbon atoms in R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specifically, methyl group, ethyl group, propyl group, isopropyl group, n- Examples thereof include a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms in R is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is particularly preferable.
As R, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms is preferable, and a hydrogen atom or a methyl group is particularly preferable from the viewpoint of industrial availability.

[Vx ⁰¹ ]
In the formula (b1-u1), Vx ⁰¹ is a divalent hydrocarbon group having an ether bond or an amide bond, a divalent aromatic hydrocarbon group or a single bond, and preferably a single bond.
The hydrocarbon group of Vx ⁰¹ may be either an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.

-Aliphatic Hydrocarbon Group The aliphatic hydrocarbon group as the divalent hydrocarbon group in Vx ⁰¹ may be saturated or unsaturated, and is usually preferably saturated.
Specific examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group and an aliphatic hydrocarbon group containing a ring in the structure.
Examples of Vx ⁰¹ include those in which the above divalent hydrocarbon group has an ether bond or an amide bond.

.. linear or branched aliphatic hydrocarbon group The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and 1 to 4 carbon atoms. More preferably, 1-3 are the most preferable.
As the linear aliphatic hydrocarbon group, preferably a linear alkylene group, and specific examples include a methylene group _[-CH 2 -], an ethylene group _{[- (CH 2) 2 -} ], trimethylene [ _{- (CH 2) 3 -]} , a tetramethylene group _{[- (CH 2) 4 -} ], a pentamethylene group _{[- (CH 2) 5 -} ] , and the like.
The branched-chain aliphatic hydrocarbon group preferably has 3 to 10 carbon atoms, more preferably 3 to 6, further preferably 3 or 4, and most preferably 3.
As the branched aliphatic hydrocarbon group, preferably a branched chain alkylene group, _{specifically, -CH (CH 3) -,} - CH (CH 2 CH 3) -, - C (CH 3) _{2 -, - C (CH 3} ) (CH 2 CH 3) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as - _{CH (CH 3) CH 2 -} , - CH (CH 3) CH (CH 3) -, - C (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - C (CH 2 Alkylethylene group such as CH ₃ ) ₂ —CH ₂ —; alkyltrimethylene group such as —CH(CH ₃ )CH ₂ CH ₂ —, —CH ₂ CH(CH ₃ )CH ₂ —; —CH(CH ₃ ). Examples thereof include alkyl alkylene groups such as alkyl tetramethylene groups such as CH ₂ CH ₂ CH ₂ —, —CH ₂ CH(CH ₃ )CH ₂ CH ₂ — and the like. As the alkyl group in the alkylalkylene group, a linear alkyl group having 1 to 5 carbon atoms is preferable.

..Aliphatic hydrocarbon group containing a ring in the structure As the aliphatic hydrocarbon group containing a ring in the structure, an alicyclic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring) , A group in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, or an alicyclic hydrocarbon group in the middle of a linear or branched aliphatic hydrocarbon group And a group intervening in. Examples of the linear or branched aliphatic hydrocarbon group include the same ones as described above.
The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The alicyclic hydrocarbon group may be polycyclic or monocyclic. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, and specifically, adamantane. , Norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.

-Aromatic Hydrocarbon Group The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring.
The aromatic hydrocarbon group as the divalent hydrocarbon group in Vx ⁰¹ preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, further preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and 6 carbon atoms. Most preferably, 10 to 10. However, the number of carbon atoms does not include the number of carbon atoms in the substituent.
Specific examples of the aromatic ring included in the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; some of the carbon atoms constituting the aromatic hydrocarbon ring are hetero. Aromatic heterocycles substituted with atoms; and the like. Examples of the hetero atom in the aromatic heterocycle include an oxygen atom, a sulfur atom and a nitrogen atom.
Specific examples of the aromatic hydrocarbon group include a group obtained by removing two hydrogen atoms from the aromatic hydrocarbon ring (arylene group, preferably phenylene group, naphthylene group); hydrogen atom from the aromatic hydrocarbon ring. A group in which one of the hydrogen atoms of the group except one (aryl group) is substituted with an alkylene group (for example, a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, 2 -A group obtained by removing one more hydrogen atom from an aryl group in an arylalkyl group such as a naphthylethyl group); The alkylene group (alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

[Yx ⁰¹ ]
In general formula (b1-u1), Yx ⁰¹ represents a single bond or a divalent linking group.
The divalent linking group for Yx ⁰¹ is not particularly limited, but examples thereof include a divalent hydrocarbon group which may have a substituent and a divalent linking group containing a hetero atom.

-Divalent hydrocarbon group which may have a substituent The hydrocarbon group as the divalent linking group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.
The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.
Examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, and the like.

Examples of the linear aliphatic hydrocarbon group, the branched aliphatic hydrocarbon group, and the aliphatic hydrocarbon group having a ring in the structure in Yx ⁰¹ include the linear aliphatic hydrocarbon group in Vx ⁰¹ . And branched aliphatic hydrocarbon groups and aliphatic hydrocarbon groups containing a ring in the structure, respectively.

The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and a carbonyl group.

The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group and a carbonyl group.
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group or a tert-butyl group.
As the alkoxy group as the substituent, an alkoxy group having 1 to 5 carbon atoms is preferable, a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group and a tert-butoxy group are preferable, and a methoxy group is preferable. Most preferred is the group ethoxy.
Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent include groups in which a part or all of the hydrogen atoms of the alkyl group are substituted with the halogen atom.
In the cyclic aliphatic hydrocarbon group, a part of carbon atoms constituting the ring structure may be substituted with a substituent containing a hetero atom. As the substituent containing the hetero atom, -O-, -C(=O)-O-, -S-, -S(=O) _2- , and -S(=O) _2- O- are preferable.

Examples of the aromatic hydrocarbon group for Yx ⁰¹ include the same as the aromatic hydrocarbon group for Vx ⁰¹ described above.
In the aromatic hydrocarbon group, the hydrogen atom of the aromatic hydrocarbon group may be substituted with a substituent. For example, the hydrogen atom bonded to the aromatic ring in the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group and the like.
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group or a tert-butyl group.
Examples of the alkoxy group, the halogen atom and the halogenated alkyl group as the substituent include those exemplified as the substituent for substituting the hydrogen atom of the cyclic aliphatic hydrocarbon group.

-Divalent linking group containing a hetero atom The hetero atom in the divalent linking group containing a hetero atom is an atom other than a carbon atom and a hydrogen atom, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom. Can be mentioned.

When Yx ⁰¹ is a divalent linking group containing a hetero atom, preferable examples of the linking group include —O—, —C(═O)—O—, —C(═O)—, and —O—C. (=O)-O-, -C(=O)-NH-, -NH-, -NH-C(=NH)-(H may be substituted with a substituent such as an alkyl group and an acyl group. _{.), - S -, -} S (= O) 2 -, - S (= O) 2 -O-, the formula ^{-Y 21 -O-Y 22 -,} - Y 21 -O -, - Y 21 - ^{C (= O) -O -,} - C (= O) -O-Y 21, [Y 21 -C (= O) -O] m '-Y 22 - or ^-Y 21 -O-C (= O ) —Y ²² — A group represented by the formula, wherein Y ²¹ and Y ²² are each independently a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m is 'Is an integer of 0 to 3. ] Etc. are mentioned.
When the divalent linking group containing a hetero atom is -C(=O)-NH-, -NH-, -NH-C(=NH)-, H is a substituent such as an alkyl group or acyl. It may be substituted. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.
Formula ^{-Y 21 -O-Y 22 -,} - Y 21 -O -, - Y 21 -C (= O) -O -, - C (= O) -O-Y 21, - [Y 21 -C ( _{= O) -O] m '-Y} 22 - or ^{-Y 21 -O-C (= O} ) -Y 22 - ^{in, Y 21} and ^{Y 22} each independently have a substituent It is a good divalent hydrocarbon group. Examples of the divalent hydrocarbon group include those similar to the “divalent hydrocarbon group which may have a substituent” mentioned in the description of the divalent linking group.
As Y ²¹ , a linear aliphatic hydrocarbon group is preferable, a linear alkylene group is more preferable, a linear alkylene group having 1 to 5 carbon atoms is further preferable, and a methylene group or an ethylene group is particularly preferable. preferable.
As Y ²² , a linear or branched aliphatic hydrocarbon group is preferable, and a methylene group, an ethylene group or an alkylmethylene group is more preferable. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.
Formula ^{- [Y 21 -C (= O} ) -O] m '-Y 22 - In the group represented by, m' is an integer of 0 to 3, preferably an integer of 0 to 2, 0 Alternatively, 1 is more preferable, and 1 is particularly preferable. In other words, the formula ^- Examples of the group represented by the formula ^{-Y 21 -C (= O) -O} -Y 22 - - [Y 21 -C (= O) -O] m '-Y 22 represented by Groups are particularly preferred. Among them, the formula _{- (CH 2) a '-C} (= O) -O- (CH 2) b' - a group represented by are preferred. In the formula, a′ is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, still more preferably 1 or 2, and most preferably 1. b′ is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, further preferably 1 or 2, and most preferably 1.

Among them, Yx ⁰¹ is preferably a divalent linking group, more preferably a divalent linking group containing a hetero atom, an ester bond [-C(=O)-O-], an ether bond (-O-). It is particularly preferable that it is a linear or branched alkylene group, or a combination thereof.

[Rx ¹ ]
In the formula (b1-u1), Rx ¹ is an organic group containing a neutralizing group.
The organic group containing a neutralizing group is not particularly limited as long as the block chain (b1) and the resist prepattern are bound by neutralization to form a developer insoluble layer on the surface of the resist prepattern. ..
As the organic group containing a neutralizing group, for example, an organic group having a nitrogen atom is preferable, and one having a high pKa of the conjugate acid is more preferable. Specifically, an organic group having a nitrogen atom and a conjugate acid having a pKa of -3 to 15 is preferable.

Examples of the organic group containing a neutralizing group include primary aliphatic amines, secondary aliphatic amines, tertiary aliphatic amines, aromatic amines or heterocyclic amines. It can be mentioned as a suitable one.
Examples of the aliphatic amines include ethylamine, n-propylamine, sec-butylamine, tert-butylamine, hexylamine, cyclohexylamine, octylamine, dodecylamine, ethylenediamine, tetraethylenepentamine, dimethylamine, diethylamine and di-n-. Propylamine, diisopropylamine, di-n-butylamine, diisobutylamine, di-sec-butylamine, dipentylamine, dihexylamine, dicyclohexylamine, dioctylamine, didodecylamine, N,N-dimethylethylenediamine, N,N-dimethyltetraamine Ethylene pentamine, trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, triisobutylamine, tri-sec-butylamine, tripentylamine, trihexylamine, tricyclohexylamine, triheptylamine , Trioctylamine, tridecylamine, tridodecylamine, N,N,N',N'-tetramethylmethylenediamine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N '-Tetramethyltetraethylenepentamine, dimethylethylamine, methylethylpropylamine, benzylamine, phenethylamine, benzyldimethylamine, monoethanolamine, diethanolamine, triethanolamine, N-ethyldiethanolamine, N,N-diethylethanolamine, tri Examples include isopropanolamine, 2-aminoethanol, 3-amino-1-propanol, 4-amino-1-butanol, 2,2,6,6,tetramethylpiperidine, 2,2,6,6 and pentamethylpiperidine. To be done.

Examples of aromatic amines or heterocyclic amines include aniline, diphenyl(p-tolyl)amine, methyldiphenylamine, triphenylamine, phenylenediamine, naphthylamine, diaminonaphthalene, pyrrole, oxazole, thiazole, imidazole, pyrazole, furazan, pyrroline. , Pyrrolidine, imidazoline, imidazolidine, pyridine (preferably 2-(2-hydroxyethyl)pyridine), pyridazine, pyrimidine, pyrazine, pyrazoline, pyrazolidine, piperidine, piperazine (preferably 1-(2-hydroxyethyl)piperazine, 1 -[2-(2-hydroxyethoxy)ethyl]piperazine), morpholine (preferably 4-(2-hydroxyethyl)morpholine), indole, isoindole, 1H-indazole, indoline, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline. , Phthalazine, purine, pteridine, carbazole, phenanthridine, acridine, phenazine, 1,10-phenanthroline, adenine, adenosine, guanine, guanosine, uracil, uridine and the like.
These aromatic amines or heterocyclic amines may have a substituent. Preferred substituents which may be present are a hydroxyl group, an amino group, an alkyl group, an alkoxy group, an acyl group, an acyloxy group, an aryl group, an aryloxy group, a nitro group, a cyano group, an ester group and a lactone group.

Among them, Rx ¹ is preferably a group represented by any one of the following general formulas (Rx-1) and (Rx-2).

［式中、Ｒｘ^０１〜Ｒｘ^０４はそれぞれ独立に水素原子又は直鎖状若しくは分岐鎖状のアルキル基であり、ｎは０〜８の整数であり、＊はＹｘ^０１との結合手を示す。］

^Wherein, Rx 01 ^{to Rx 04} are each independently a hydrogen atom or a linear or branched alkyl group, n is an integer of 0-8, * represents a bond to ^{Yx 01.} ]

In the above formula, the linear or branched alkyl group of Rx ^{01 to} Rx ⁰⁴ is preferably an alkyl group having 1 to 10 carbon atoms; specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group. , N-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, 1,1-dimethylethyl group, 1,1-diethylpropyl group, 2,2-dimethylpropyl group, 2,2 , -Dimethylbutyl group and the like.
Of these, a methyl group or an ethyl group is preferable.
n is an integer of 0 to 8 and is preferably 2 or 4.

Specific examples of the group represented by formula (Rx-1) are shown below. In the following specific examples, * indicates a bond.

The group represented by the formula (Rx-2) means a cyclic amine.
As the group represented by the general formula (Rx-2), a group represented by the following general formula (Rx-2-1) is preferable. As the group represented by general formula (Rx-2-1) shown below, the group represented by general formula (Rx-2-1-1) is particularly preferable.

［式中、Ｒｘ^０５〜Ｒｘ^０６、Ｒｘ^０６１〜Ｒｘ^０６４はそれぞれ独立に水素原子又は直鎖状若しくは分岐鎖状のアルキル基であり、ｎ１は０〜８の整数であり、＊はＹｘ^０１との結合手を示す。］

[In the formula, Rx ^{05 to} Rx ⁰⁶ and Rx ^{061 to} Rx ⁰⁶⁴ are each independently a hydrogen atom or a linear or branched alkyl group, n1 is an integer of 0 to 8, and * represents Yx ⁰¹ and Shows the hand of joining. ]

The linear or branched alkyl group of Rx ^{05 to} Rx ⁰⁶ and Rx ^{061 to} Rx ⁰⁶⁴ is the same as described above for Rx ^{01 to} Rx ⁰⁴ . n1 is an integer of 0-8.

Specific examples of the group represented by formula (Rx-2) are shown below. In the following specific examples, * indicates a bond.

As the constitutional unit represented by the general formula (b1-u1), a constitutional unit represented by any of the following general formulas (b1-u1-1) to (b1-u1-3) is preferable.

［式中、Ｒは、水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基である。Ｙｘ^０１’は単結合又は２価の炭化水素基である。Ｒｘ^１は中和性基を含む有機基を示す。］

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Yx 01 ^'is a single bond or a divalent hydrocarbon group. Rx ¹ represents an organic group containing a neutralizing group. ]

In the formulas (b1-u1-1) to (b1-u1-3), R, Yx ⁰¹ and Rx ¹ are the same as described above. The divalent hydrocarbon group for Yx ⁰¹ ′ is the same as the description for the divalent hydrocarbon group for Yx ⁰¹ .

Below, the specific example of the structural unit represented by general formula (b1-u1) is described. In the following specific examples, R is the same as above.

The weight average molecular weight (Mw) (based on polystyrene conversion by gel permeation chromatography) of the partial constituent components (repeating structures of the same kind of constituent units) constituting the block chain (b1) is not particularly limited, but is 1000 -50000 is preferable, 1000-30000 is more preferable, 1000-10000 is still more preferable.

-Other block chain The block chain other than the block chain (b1) contained in the block copolymer in the present invention is not particularly limited, and examples thereof include a structural unit having a styrene skeleton, a structural unit (a3) described below, Partial constituent components in which the structural unit (a4) or the structural unit (a9) represented by general formula (a9-1) shown below are repeatedly bonded are included.

..Partial constituent components in which constituent units having a styrene skeleton are repeatedly bonded (hereinafter referred to as "block chain (b2)")
The block copolymer in the present invention preferably contains a block chain (b2) in addition to the block chain (b1).
By including the block chain (b2) in addition to the block chain (b1), the resist prepattern can be thickened more efficiently.

Examples of the structural unit having a styrene skeleton include a hydroxystyrene, a hydroxystyrene derivative, or a structural unit (st) derived from styrene (hereinafter referred to as "structural unit (st)").
The number of hydroxyl groups bonded to the benzene ring of hydroxystyrene is preferably an integer of 1 to 3, and more preferably 1.
Examples of the preferable structural unit (st) include a structural unit (st1) represented by the following general formula (I) and a structural unit (st2) represented by the following general formula (II).

［式（Ｉ）中、Ｒ^ｓｔは水素原子又はメチル基を表し、ｍ_０１は１〜３の整数を表す。式（ＩＩ）中、Ｒ^ｓｔは水素原子又はメチル基を表し、Ｒ^０１は炭素数１〜５のアルキル基を表し、ｍ_０２は０または１〜３の整数を表す。］

[In the formula (I), R ^st represents a hydrogen atom or a methyl group, and m ₀₁ represents an integer of 1 to 3. In the formula (II), R ^st represents a hydrogen atom or a methyl group, R ⁰¹ represents an alkyl group having 1 to 5 carbon atoms, and m ₀₂ represents 0 or an integer of 1 to 3. ]

In the formula (I), R ^st is a hydrogen atom or a methyl group, and preferably a hydrogen atom.
m ₀₁ is an integer of 1 to 3, and is preferably 1.
The position of the hydroxyl group may be any of o-position, m-position and p-position. Those having m of 1 and having a hydroxyl group at the p-position are preferred because they are easily available and inexpensive. When m ₀₁ is 2 or 3, arbitrary substitution positions can be combined.

In the formula (II), R ^st is a hydrogen atom or a methyl group, and preferably a hydrogen atom.
R ⁰¹ is a linear or branched alkyl group having 1 to 5 carbon atoms, and is a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl. Group, neopentyl group and the like. Industrially, a methyl group or an ethyl group is preferred.

The m ₀₂ is 0 or an integer of 1 to 3. Of these, m ₀₂ is preferably 0 or 1, and industrially preferably 0.
In addition, when m ₀₂ is 1, the substitution position of R ⁰¹ may be any of o-position, m-position and p-position, and when m ₀₂ is 2 or 3, it is optional. The substitution positions can be combined.

The weight average molecular weight (Mw) (based on polystyrene conversion by gel permeation chromatography) of the partial constituent components (repeating structures of the same kind of constituent units) constituting the block chain (b2) is not particularly limited, but is 1000 ˜200000 is preferable, 1000 to 100000 is more preferable, and 1000 to 50000 is further preferable.

..Partial structural components in which the structural unit (a9) is repeatedly bonded (hereinafter referred to as "block chain (b3)")
The block copolymer in the present invention may contain a block chain (b3) in addition to the block chain (b1).
The structural unit (a9) is a structural unit represented by general formula (a9-1) shown below.

［式中、Ｒは前記と同様であり、Ｙａ^９１は単結合または２価の連結基であり、Ｒ^９１は置換基を有していてもよい炭化水素基であり、Ｙａ^９２は２価の連結基である。］

[In the formula, R is as defined above, Ya ⁹¹ is a single bond or a divalent linking group, R ⁹¹ is a hydrocarbon group which may have a substituent, and Ya ⁹² is a divalent group. It is a linking group. ]

In the formula (a9-1), the divalent linking group for Ya ⁹¹ may be the same as the divalent linking group for Yx ⁰¹ in the formula (b1-u1). Ya ⁹¹ is preferably a single bond.
In the formula (a9-1), the divalent linking group for Ya ⁹² is the same as the divalent linking group for Ya ⁹¹ described above, and the divalent linking group for Yx ⁰¹ in the formula (b1-u1) (substitution And a divalent hydrocarbon group which may have a group, a divalent linking group containing a hetero atom, etc.).

In the divalent linking group for Ya ⁹² in formula (a9-1), the divalent hydrocarbon group that may have a substituent is a linear or branched aliphatic hydrocarbon group. preferable.
As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferable, the number of carbon atoms is preferably 1-10, more preferably 1-6, further preferably 1-4, and 1-3. Is most preferred. Specifically, a methylene group _[-CH 2 -], an ethylene group _{[- (CH 2) 2 -} ], a trimethylene group _{[- (CH 2) 3 -} ], a tetramethylene group _{[- (CH 2) 4 -} ] , a pentamethylene group _{[- (CH 2) 5 -} ] , and the like.
The branched-chain aliphatic hydrocarbon group is preferably a branched-chain alkylene group, has preferably 3 to 10 carbon atoms, more preferably has 3 to 6 carbon atoms, and further preferably has 3 or 4 carbon atoms. _{Specifically, -CH (CH 3) -,} - CH (CH 2 CH 3) -, - C (CH 3) 2 -, - C (CH 3) (CH 2 CH 3) -, - C (CH _{3) (CH 2 CH 2 CH} 3) -, - C (CH 2 CH 3) 2 - alkyl groups such _{as; -CH (CH 3) CH 2} -, - CH (CH 3) CH (CH 3) - _{, -C (CH 3) 2 CH} 2 -, - CH (CH 2 CH 3) CH 2 -, - C (CH 2 CH 3) 2 -CH 2 - alkyl groups such as; -CH _(CH 3) CH _{2 CH 2 -, - CH 2} CH (CH 3) CH 2 - alkyl trimethylene groups such _{as; -CH (CH 3) CH 2} CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 - And an alkyl alkylene group such as an alkyl tetramethylene group. As the alkyl group in the alkylalkylene group, a linear alkyl group having 1 to 5 carbon atoms is preferable.
The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and a carbonyl group.

Further, in the divalent linking group for Ya ⁹² in formula (a9-1), the divalent linking group optionally having a hetero atom includes —O— and —C(═O)—O—. , -C(=O)-, -OC(=O)-O-, -C(=O)-NH-, -NH-, -NH-C(=NH)-(H is an alkyl group, with a substituent such as an acyl group which may be _{substituted), -. S -, -} S (= O) 2 -, - S (= O) 2 -O -, - C (= S) -, the formula ^{-Y 91 -O-Y 92 -,} - Y 91 -O -, - Y 91 -C (= O) -O -, - C (= O) -O-Y 91, [Y 91 -C (= O ) -O] _{m '-Y} ⁹² - or ^{-Y 91 -O-C (= O} ) -Y 92 - group [wherein represented ^{by, Y 91} and ^{Y 92} each independently have a substituent Is a divalent hydrocarbon group which may be present, O is an oxygen atom, and m′ is an integer of 0 to 3. ] Etc. are mentioned. Among them, -C(=O)- and -C(=S)- are preferable.

In the formula (a9-1), examples of the hydrocarbon group for R ⁹¹ include an alkyl group, a monovalent alicyclic hydrocarbon group, an aryl group and an aralkyl group.
The alkyl group for R ⁹¹ preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and may be linear or branched. Specific examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and an octyl group.
The monovalent alicyclic hydrocarbon group for R ⁹¹ preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms, and may be polycyclic or monocyclic. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclobutane, cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms from polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, and specifically, Examples include adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.
The aryl group for R ⁹¹ preferably has 6 to 18 carbon atoms, more preferably 6 to 10 carbon atoms, and specifically preferably a phenyl group.
The aralkyl group for R ⁹¹ is preferably an aralkyl group having 7 to 10 carbon atoms, and examples of the aralkyl group having 7 to 10 carbon atoms include a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, and a 1-naphthyl group. Examples of the arylalkyl group include an ethyl group and a 2-naphthylethyl group.

The hydrocarbon group for R ⁹¹ may have a substituent. Examples of the substituent include a halogen atom, an oxo group (= O), a hydroxyl group (-OH), a amino group _{(-NH 2), - SO 2} -NH 2 , and the like.
The hydrocarbon group for R ⁹¹ is preferably such that a part or all of the hydrogen atoms of the hydrocarbon group are substituted with fluorine atoms, and 30 to 100% of the hydrogen atoms of the hydrocarbon group are substituted with fluorine atoms. Is more preferable. Among them, it is particularly preferable that the above-mentioned alkyl group is a perfluoroalkyl group in which all the hydrogen atoms are substituted with fluorine atoms.

Further, some of the carbon atoms constituting the hydrocarbon group for R ⁹¹ may be substituted with a substituent containing a hetero atom. Examples of the substituent containing the hetero atom include -O-, -NH-, -N=, -C(=O)-O-, -S-, -S(=O) _2- , -S(=O. ) _2- O- is mentioned.
Examples of the hydrocarbon group having a substituent in R ⁹¹ include lactone-containing cyclic groups represented by general formulas (a2-r-1) to (a2-r-7) described below.
In R ⁹¹ , as the hydrocarbon group having a substituent, a —SO ₂ —-containing cyclic group represented by each of general formulas (a5-r-1) to (a5-r-4) described below; Examples thereof include a substituted aryl group and a monovalent heterocyclic group represented by a chemical formula.
In the following formula, “*” indicates a bond with Ya ⁹² .

The structural unit (a9) is preferably a structural unit represented by general formula (a9-1-1) shown below.

［式中、Ｒは前記と同様であり、Ｙａ^９１は単結合または２価の連結基であり、Ｒ^９１は置換基を有していてもよい炭化水素基であり、Ｒ^９２は酸素原子又は硫黄原子である。］

[In the formula, R is as defined above, Ya ⁹¹ is a single bond or a divalent linking group, R ⁹¹ is a hydrocarbon group which may have a substituent, and R ⁹² is an oxygen atom or It is a sulfur atom. ]

In the formula (a9-1-1), the description about Ya ⁹¹ , R ⁹¹ , and R is the same as above.
R ⁹² is an oxygen atom or a sulfur atom.

Specific examples of the structural unit (a9) are shown below.
In the formula below, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

The weight average molecular weight (Mw) (based on polystyrene equivalent by gel permeation chromatography) of the partial constituent components (repeating structures of the same kind of constituent units) constituting the block chain (b3) is not particularly limited, but is 1000 ˜200000 is preferable, 1000 to 100000 is more preferable, and 1000 to 50000 is further preferable.

As the block copolymer in the present invention, a block chain (b1) having a function of thickening a resist pre-pattern and a block chain (b2) which is a partial constituent in which structural units having a styrene skeleton are repeatedly bonded Those containing are preferable.
Among these, as the block copolymer, the partial structural component in which the structural unit represented by the general formula (b1-u1) is repeatedly bonded and the structural unit (st2) represented by the general formula (II) are repeatedly bonded. It is more preferable that the above-mentioned partial component is included.

The molar ratio of the block chain (b1) to the block chain (b2) is such that the structural unit of the block chain (b1)/the structural unit of the block chain (b2)=1/99 to 50/50. Is preferred, 1/99 to 30/70 is more preferred, and 1/99 to 20/80 is even more preferred.
When the molar ratio is within the above-mentioned preferred range, the effect of thickening the resist prepattern is likely to be improved.

The block copolymer in the present invention preferably contains the block chain (b1) at the end of the main chain.
The term “including the block chain (b1) at the end of the main chain” may mean that the end of the main chain is the block chain (b1), or the end of the main chain is not the block chain (b1) but another block chain. May be Among them, the terminal of the main chain is preferably the block chain (b1).
When the end of the main chain is the other block chain, it is preferable that the block chain (b1) is closer to the end of the main chain.
By including the block chain (b1) at the end of the main chain, even if a low molecular weight polymer is adopted as the block copolymer, the effect of thickening the resist prepattern can be sufficiently obtained (thickened portion). Width (shrink volume: S.V. can be increased).
The closer the block chain (b1) is to the end of the main chain, the more the block chain (b1) interacts with the resist pre-pattern, and the other block chains easily move away from the resist pre-pattern, forming a developer insoluble layer. It becomes easy to be affected.

The weight average molecular weight (Mw) of the block copolymer (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 1000 to 200000, more preferably 1000 to 100000, and further preferably It is 1,000 to 50,000. The higher the Mw of the block copolymer, the larger the width (shrink volume: SV) of the thickened portion can be.
The dispersity (weight average molecular weight/number average molecular weight) of the block copolymer is preferably 1.5 or less, more preferably 1.45 or less, further preferably 1.4 or less, and particularly preferably 1.3 or less.

As the block copolymer in the present invention, it is preferable to use a block copolymer obtained by living polymerization, because the effect of thickening the resist prepattern can be further enhanced by narrowing the dispersion. Examples of preferable living polymerization include living anionic polymerization and living radical polymerization.
In the pattern thickening polymer composition, one type of such block copolymer may be used alone, or two or more types may be used in combination.

The polymer composition for pattern thickening also includes a polymer other than the above block copolymer (hereinafter referred to as “polymer (P2)”) from the viewpoint of controlling the pattern shape before and after thickening the resist prepattern. You may have.

<<Polymer (P2)>>
The polymer (P2) is not particularly limited, and examples thereof include those that do not have the function of thickening the resist prepattern (polymers that cannot form a developer insoluble layer on the resist prepattern surface in step C). ..
As the preferred polymer (P2), the following structural unit (a1), structural unit (a2), structural unit (a3), structural unit (a4), the structural unit (st) and the following general formula (a5-1) Examples thereof include those having at least one selected from the group consisting of the structural unit (a5) represented.

［式中、Ｒは前記と同様であり、Ｒａ^５１は炭素数１〜５の直鎖若しくは分岐鎖状のアルキル基、又は炭素数１〜５の直鎖若しくは分岐鎖状のフッ素化アルキル基である。］

[In the formula, R is the same as above, and Ra ⁵¹ is a linear or branched alkyl group having 1 to 5 carbon atoms, or a linear or branched fluorinated alkyl group having 1 to 5 carbon atoms. is there. ]

In the formula (a5-1), R has the same meaning as above.
In the formula (a5-1), Ra ⁵¹ is a linear or branched alkyl group having 1 to 5 carbon atoms, or a linear or branched fluorinated alkyl group having 1 to 5 carbon atoms. ..
Examples of the linear or branched alkyl group having 1 to 5 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group. Groups and the like.
Examples of the linear or branched fluorinated alkyl group having 1 to 5 carbon atoms include groups in which some or all of the hydrogen atoms of the above alkyl group having 1 to 5 carbon atoms are substituted with fluorine atoms.

The polymer (P2) may be a copolymer or a homopolymer.
When the polymer (P2) is a copolymer, it preferably has at least one selected from the group consisting of structural units (a1) to (a5), and consists of structural unit (a3) and structural unit (a4). It is more preferable to have at least one selected from the group.
When the polymer (P2) is a homopolymer, it preferably has a structural unit (a5) or a structural unit (st).
Specifically, the polymer (P2) includes a copolymer composed of the structural unit (a3) and the structural unit (a4), a copolymer composed of the structural unit (a4) and the structural unit (a5), and the structural unit (a1). And a copolymer composed of the structural unit (a3), a copolymer composed of the structural units (a1), (a2) and (a3), a homopolymer composed of the structural unit (a5), and a homopolymer composed of the structural unit (st). Polymers are preferred.

When the polymer (P2) is a copolymer, the proportions of the structural units (a1) to (a5) and (st) in the polymer (P2) are not particularly limited, and may be in all structural units constituting the polymer (P2). On the other hand, it can be appropriately adjusted within the range of 1 to 99 mol %.

The polymer (P2) can be obtained by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate for the monomer that induces each structural unit.

The weight average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography) of the polymer (P2) is not particularly limited and is preferably 1000 to 1,000,000, more preferably 1500 to 500000, most preferably 2000 to 300000. preferable.
When the weight average molecular weight of the polymer (P2) is within the above range, the pattern can be satisfactorily thickened.

In the polymer composition for pattern thickening, the polymer (P2) may be used alone or in combination of two or more.
In the pattern thickening polymer composition, the mass ratio of the block copolymer to the polymer (P2) is preferably block copolymer/polymer (P2)=1/99 to 99/1. /95 to 95/5 is more preferable, and 10/90 to 90/10 is further preferable.

<<solvent>>
The solvent contained in the pattern thickening polymer composition may be water or an organic solvent, and is not particularly limited as long as it does not dissolve the resist pre-pattern, and the pattern thickening used It can be appropriately selected depending on the polymer composition material for use or the resist composition. It is preferable to use an organic solvent as the solvent.
When water is used as the solvent, pure water is preferable, and when an organic solvent is used, a ketone solvent, an ester solvent, an alcohol solvent, an amide solvent, an ether solvent, etc., or a mixed solvent of two or more thereof. Is preferably used.
Among these, from the viewpoint of not dissolving the resist pre-pattern, it is more preferable to use an ester solvent, and it is particularly preferable to use butyl acetate.
The total solid content concentration (total mass excluding the solvent) of the pattern thickening polymer composition is preferably 0.1 to 20 mass% with respect to the total amount (100 mass%) of the pattern thickening polymer composition. , More preferably 0.1 to 10% by mass, further preferably 0.1 to 5% by mass.

<Method of forming resist pattern>
Hereinafter, the resist pattern forming method of the present invention will be described with reference to the drawings. However, the present invention is not limited to this.
FIG. 1 is a schematic process diagram for explaining one embodiment of a resist pattern forming method according to the present invention, showing a series of processes for thickening a hole pattern.
First, a resist prepattern 2 is formed on a support 1 using a resist composition (step A; FIG. 1A). In the resist pre-pattern 2, the diameter of the hole is T ₁ .
Next, the pattern thickening polymer composition is applied onto the support 1 having the resist pre-pattern 2 formed thereon so as to cover the resist pre-pattern 2 to form a polymer film 3 (step B; FIG. 1). (B)).
Then, a developer insoluble layer 3a (thickened portion) is formed on the surface of the resist prepattern 2 (step C; FIG. 1C).
Then, the resist pre-pattern 2 having the developer insoluble layer 3a formed on the surface and the polymer film 3 covering the resist pre-pattern 2 are developed. As a result, in the present embodiment, the resist pre-pattern 2 is thickened in the height direction and the radial direction of the hole, and the fine resist pattern 4 having a smaller hole diameter than the resist pre-pattern 2 is formed ( Step D; FIG. 1(d)).
In FIG. 1D, the resist pattern 4 is a hole pattern composed of the resist prepattern 2 and the developer insoluble layer 3a. In the resist pattern 4, the resist pre-pattern 2 is thickened, and the diameter of the hole is reduced from T ₁ to T ₂ (T ₂ <T ₁ ). The width of the thickened portion in the radial direction of the hole (shrink volume: S.V.) is set to T ₀ (that is, T ₁ −T ₀ =T ₂ , T ₀ =T _0a +T _0b ).

[Process A]
Step A is a step of forming the resist prepattern 2 on the support 1.
As a method of forming the resist pre-pattern 2, for example, a step of forming a resist film on the support 1 using a resist composition described later, a step of exposing the resist film, and a step of developing the exposed resist film. Then, a method including a step of forming the resist pre-pattern 2 is mentioned.

The resist prepattern can be formed as follows, for example.
First, a resist composition described below is applied on a support by a spinner or the like, and a baking (post-apply bake (PAB)) treatment is performed, for example, at a temperature condition of 80 to 150° C. for 40 to 120 seconds, preferably 60 to 60° C. It is applied for 90 seconds to form a resist film.
Next, using an exposure device such as an ArF exposure device, an electron beam exposure device, and an EUV exposure device, the resist film is exposed through a mask (mask pattern) on which a predetermined pattern is formed or a mask pattern. After performing selective exposure such as drawing by direct irradiation with an electron beam not through, a baking (post exposure bake (PEB)) treatment is performed, for example, at a temperature condition of 80 to 150° C. for 40 to 120 seconds, preferably 60 to Apply for 90 seconds.

Next, the resist film is developed.
The development treatment is performed using an alkali developing solution in the case of an alkali developing process and using a developing solution containing an organic solvent (organic developing solution) in the case of a solvent developing process.
The development treatment may be an alkali development process or a solvent development process, but is preferably a solvent development process. That is, step A preferably includes an operation of developing a resist film with an organic solvent to form a resist pre-pattern, and further, a resist composition containing a resin component whose solubility in an organic solvent is reduced by the action of acid. It is more preferable to include an operation of forming a resist film on a support using a material and an operation of developing the resist film with an organic solvent to form a resist pre-pattern.

After the development processing, rinsing processing is preferably performed. The rinse treatment is preferably a water rinse using pure water in the case of an alkali development process, and preferably a rinse liquid containing an organic solvent in the case of a solvent development process.
In the case of the solvent developing process, after the developing process or the rinsing process, a process of removing the developing solution or the rinsing solution adhering to the pattern with a supercritical fluid may be performed.
After development or rinsing, drying is performed. In some cases, a bake treatment (post bake) may be performed after the above development treatment.
In this way, a resist pre-pattern can be obtained.

Although FIG. 1 shows a series of steps for thickening the hole pattern, the shape of the resist pre-pattern is not particularly limited, and may be a line pattern, a trench pattern, or the like.
The method of forming a resist pattern of the present invention is particularly useful when the shape of the resist pre-pattern in step A is a hole pattern, and in this case, it contains a resin component whose solubility in an organic solvent decreases due to the action of acid. And a step of forming a resist film on a support using a resist composition to form a resist pre-pattern by developing the resist film with an organic solvent, in addition to the block chain ( The neutralizing group contained in b1) is preferably a basic group.

The support is not particularly limited, and a conventionally known support can be used, and examples thereof include a substrate for electronic parts, and a support having a predetermined wiring pattern formed thereon. More specifically, a silicon wafer, a substrate made of metal such as copper, chromium, iron, and aluminum, a glass substrate, or the like can be given. As the material of the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
Further, the support may be the above-mentioned substrate provided with an inorganic and/or organic film. Examples of the inorganic film include an inorganic antireflection film (inorganic BARC). Examples of the organic film include organic films such as an organic antireflection film (organic BARC) and a lower organic film in a multilayer resist method.
Here, the multi-layer resist method means that at least one organic film (lower organic film) and at least one resist film (upper resist film) are provided on a substrate, and the resist pattern formed on the upper resist film is used as a mask. It is a method of patterning the lower organic film and is said to be capable of forming a pattern with a high aspect ratio. That is, according to the multilayer resist method, a desired thickness can be secured by the lower organic film, so that the resist film can be thinned and a fine pattern with a high aspect ratio can be formed.
The multilayer resist method basically includes a method of forming a two-layer structure of an upper layer resist film and a lower layer organic film (two-layer resist method), and one or more intermediate layers between the upper layer resist film and the lower layer organic film ( A method of forming a multi-layered structure having three or more layers (three-layer resist method) provided with a metal thin film or the like).

The exposure is not particularly limited, and radiation such as ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet ray), VUV (vacuum ultraviolet ray), EB (electron beam), X-ray, and soft X-ray is used. Can be done by

The exposure method of the resist film may be either normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or liquid immersion exposure (Liquid Immersion Lithography).
In the immersion exposure, the space between the resist film and the lens at the lowest position of the exposure apparatus is previously filled with a solvent (immersion medium) having a refractive index higher than that of air, and exposure (immersion exposure) is performed in that state. It is an exposure method.
As the liquid immersion medium, a solvent having a refractive index higher than that of air and lower than that of the resist film to be exposed is preferable. The refractive index of the solvent is not particularly limited as long as it falls within the above range.
Examples of the solvent having a refractive index higher than that of air and lower than that of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.
Specific examples of the fluorine-based inert liquid include a fluorine-based compound such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F ₇ as a main component. Examples thereof include liquids, those having a boiling point of 70 to 180° C. are preferable, and those having a boiling point of 80 to 160° C. are more preferable. It is preferable that the fluorine-based inert liquid has a boiling point within the above range because the medium used for immersion can be removed by a simple method after the exposure is completed.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all the hydrogen atoms of the alkyl group are replaced with fluorine atoms is particularly preferable. Specific examples of the perfluoroalkyl compound include a perfluoroalkyl ether compound and a perfluoroalkylamine compound.
More specifically, examples of the perfluoroalkyl ether compound include perfluoro(2-butyl-tetrahydrofuran) (boiling point 102° C.), and examples of the perfluoroalkylamine compound include perfluorotributylamine( The boiling point is 174° C.).
As the liquid immersion medium, water is preferably used from the viewpoints of cost, safety, environmental problems, versatility and the like.

Examples of the alkaline developer used for the developing treatment in the alkaline developing process include an aqueous solution of tetramethylammonium hydroxide (TMAH) of 0.1 to 10% by mass.
The organic solvent contained in the organic developer used for the developing treatment in the solvent developing process may be any one as long as it can dissolve the component (A) (component (A) before exposure) contained in the resist composition, It can be appropriately selected from known organic solvents. Specifically, a polar solvent such as a ketone solvent, an ester solvent, an alcohol solvent, an amide solvent, an ether solvent, or a hydrocarbon solvent can be used.
Known additives may be added to the organic developer as needed. Examples of the additive include a surfactant. The surfactant is not particularly limited, but for example, an ionic or nonionic fluorine-based and/or silicon-based surfactant can be used.
When the surfactant is blended, the blending amount thereof is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and 0.01 to 0. 5% by mass is more preferable.

The development treatment can be carried out by a known development method, for example, a method of immersing the support in a developing solution for a certain period of time (dip method), or raising the developing solution to the surface of the support by surface tension and then standing still for a certain period of time. Method (paddle method), spraying the developer on the surface of the support (spray method), and applying the developer while scanning the developer application nozzle at a constant speed on the support rotating at a constant speed. A method of continuing (dynamic dispensing method) and the like can be mentioned.

The rinse treatment (washing treatment) using the rinse liquid can be carried out by a known rinse method. Examples of the method include a method in which the rinse solution is continuously applied onto the support rotating at a constant speed (rotational coating method), a method in which the support is immersed in the rinse solution for a certain period of time (dip method), and the surface of the support. And a method of spraying a rinse liquid on the surface (spray method).

[Step B]
In step B, the polymer composition for pattern thickening is applied by coating the polymer composition for pattern thickening on the support 1 on which the resist prepattern 2 is formed so as to cover the resist prepattern 2 formed in step A. Is a step of forming.
The polymer film 3 is formed by, for example, applying the above-described polymer composition for pattern thickening on the support 1 on which the resist prepattern 2 is formed, and drying the composition.
As a method of applying the polymer composition for pattern thickening, a conventionally known spin coating method, spraying method, roller coating method, dipping method, or the like can be used, and a spin coating method is preferable.

[Step C]
Step C is a step of forming the developer insoluble layer 3a on the surface of the resist prepattern 2.
The polymer film 3 formed on the resist pre-pattern 2 in the step B contains a block copolymer containing a block chain (b1) having a thickening function of the resist pre-pattern 2. After the polymer film 3 is formed, the block chain (b1) interacts with the resist pre-pattern 2 to form the developer insoluble layer 3a (thickened portion).
In step C, it is preferable to heat the resist pre-pattern 2 and the polymer film 3 covering it. By such heating, the interaction between the block chain (b1) contained in the block copolymer in the polymer film 3 and the resist prepattern 2 is further strengthened, and the developer insoluble layer 3a (thickness) is formed on the resist prepattern 2 surface. It becomes easy to form a meat part). In addition, the insoluble residual solvent in the resist prepattern 2 and the polymer film 3 is removed.

The heating temperature and time depend on the type of resist material used, the type of block copolymer in the polymer composition for pattern thickening, or the required width of the thickened portion (shrink volume: SV). Therefore, it can be set appropriately.
The heating temperature is preferably 0 to 200°C, more preferably 50 to 170°C, further preferably 70 to 160°C, and particularly preferably 80 to 150°C. If the heating temperature is equal to or higher than the preferable lower limit value, S. V. Can be increased. If it is at most the preferable upper limit value, the resist pattern shape is likely to be favorably maintained.
The heating time is preferably 30 to 300 seconds, more preferably 50 to 120 seconds, and particularly preferably 50 to 80 seconds.

When the block chain (b1) contained in the block copolymer in the polymer film 3 has a neutralizing group, the block chain (b1) and the resist pre-pattern 2 are neutralized to form the resist pre-pattern. The developer insoluble layer 3a is formed on the surface of the second layer.
In this case, the neutralizing group contained in the block chain (b1) and the carboxylic acid, hydroxyl group, lactone, acid anhydride or ester (hereinafter referred to as “carboxylic acid”) on the surface of the resist prepattern are neutralized. As a result, the developer insoluble layer 3a is formed.
The surface of the resist pre-pattern is in a state where carboxylic acid or the like is exposed by deprotection or the like. Here, when the pattern thickening polymer composition is coated, the pattern thickening polymer composition contacts the resist pre-pattern, and the carboxylic acid and the like exposed on the resist pre-pattern surface, and the pattern thickening polymer composition. The neutralizing groups (basic groups) in the product are neutralized with each other to form a developer insoluble layer which is insoluble in the developer at the time of development in the subsequent step D.
In step C, the residual solvent is removed, preferably by heating, and the neutralization on the resist pre-pattern surface proceeds more favorably.

[Process D]
Step D is a step of developing the resist prepattern 2 having the developer-insoluble layer 3a formed on the surface and the polymer film 3 covering the resist prepattern 2 to form a resist pattern 4 in which the resist prepattern 2 is thickened. .. By the development in step D, the polymer film 3 portion other than the developer insoluble layer 3a and the excess or unreacted pattern thickening polymer composition are removed.
The developing treatment may be carried out by an alkali developing process or a solvent developing process. In the case of an alkali developing process, an alkali developing solution is used, and in the case of a solvent developing process, a developing solution containing an organic solvent (organic developing solution) is used. Among them, the development treatment is preferably performed by a solvent development process from the viewpoint of the removal efficiency of the pattern thickening polymer composition.

After the development processing, rinsing processing is preferably performed. The rinse treatment is preferably a water rinse using pure water in the case of an alkali development process, and preferably a rinse liquid containing an organic solvent in the case of a solvent development process.
In the case of the solvent developing process, after the developing process or the rinsing process, a process of removing the developing solution or the rinsing solution adhering to the pattern with a supercritical fluid may be performed.
After development or rinsing, drying is performed. In some cases, a bake treatment (post bake) may be performed after the above development treatment.
In this way, it is possible to obtain a target resist pattern in which the resist pre-pattern is thickened.

According to the resist pattern forming method of the present embodiment, as shown in FIG. 1D, the resist pre-pattern is thickened, so that a fine pattern with a reduced hole diameter can be formed by a simple method.
In addition, in this embodiment, since the block copolymer is used in the pattern thickening polymer composition, it is possible to sufficiently thicken the resist pre-pattern even if a low molecular weight polymer is adopted. You can

In the present embodiment, the resist pre-pattern is a hole pattern, but it is not limited to this and may be, for example, a line-and-space pattern (hereinafter referred to as “LS pattern”). When the resist pre-pattern is an LS pattern, the resist pattern forming method according to the present invention can form a fine pattern with a reduced space width by a simple method.

<Resist composition>
The resist composition that can be used in the present embodiment is preferably a resist composition that generates an acid upon exposure and whose solubility in a developing solution changes due to the action of the acid.
The resist composition preferably contains a base component (A) whose solubility in a developing solution is changed by the action of an acid (hereinafter also referred to as “component (A)”).
When a resist film is formed using such a resist composition and the resist film is selectively exposed, an acid is generated in the exposed area, and the action of the acid causes the solubility of the component (A) in a developing solution. On the other hand, the solubility of the component (A) in the developing solution does not change in the unexposed area, but a difference in solubility in the developing solution occurs between the exposed area and the unexposed area. Therefore, when the resist film is developed, the exposed part is dissolved and removed to form a positive resist pattern when the resist composition is a positive type, and the unexposed part is dissolved when the resist composition is a negative type. The resist pattern is removed to form a negative resist pattern.
In the present specification, a resist composition in which an exposed portion is dissolved and removed to form a positive resist pattern is referred to as a positive resist composition, and a resist composition which forms a negative resist pattern in which an unexposed portion is dissolved and removed. Is referred to as a negative resist composition.
In the present embodiment, the resist composition may be either a positive resist composition or a negative resist composition.
Further, in the present embodiment, the resist composition may be for an alkali developing process in which an alkali developing solution is used for the developing treatment at the time of forming a resist pattern, and the developing treatment containing an organic solvent (organic developing solution). ) May be used for the solvent development process, but is preferably for the solvent development process.

The above resist composition has an acid generating ability to generate an acid upon exposure, and the component (A) may generate an acid upon exposure, and is an additive component blended separately from the component (A). May generate an acid upon exposure.
Specifically, in this embodiment, the resist composition is
(1) It may contain an acid generator component (B) that generates an acid upon exposure (hereinafter referred to as “(B) component”);
(2) The component (A) may be a component which generates an acid upon exposure to light;
(3) The component (A) may be a component that generates an acid upon exposure, and may further contain the component (B).
That is, in the cases of the above (2) and (3), the component (A) becomes “a base material component which generates an acid upon exposure and whose solubility in a developing solution is changed by the action of the acid”. When the component (A) is a base material component that generates an acid upon exposure to light and the solubility of the developer changes by the action of the acid, the component (A1) described below generates an acid upon exposure to light, and A polymer compound whose solubility in a developing solution is changed by the action of an acid is preferable. As such a polymer compound, a resin having a structural unit that generates an acid upon exposure can be used. As the structural unit that generates an acid upon exposure, a known unit can be used.
In this embodiment, the resist composition is particularly preferably the case (1) above.

≪(A) ingredient≫
In the present embodiment, the “base material component” is an organic compound having a film-forming ability, and an organic compound having a molecular weight of 500 or more is preferably used. When the molecular weight of the organic compound is 500 or more, the film forming ability is improved and, in addition, a nano-level photosensitive resin pattern is easily formed.
The organic compound used as the base material component is roughly classified into a non-polymer and a polymer.
As the non-polymer, one having a molecular weight of 500 or more and less than 4000 is usually used. Hereinafter, the term "low molecular weight compound" means a non-polymer having a molecular weight of 500 or more and less than 4000.
As the polymer, a polymer having a molecular weight of 1,000 or more is usually used. Hereinafter, the term "resin" refers to a polymer having a molecular weight of 1000 or more.
As the molecular weight of the polymer, a polystyrene-equivalent weight average molecular weight by GPC (gel permeation chromatography) is used.
As the component (A), a resin may be used, a low molecular weight compound may be used, or these may be used in combination.
The component (A) is one whose solubility in a developing solution changes due to the action of an acid.
Further, in the present embodiment, the component (A) may generate an acid upon exposure.

In the present embodiment, the component (A) is a polymer compound (A1) having a structural unit containing an acid-decomposable group whose polarity is increased by the action of an acid (hereinafter sometimes referred to as “structural unit (a1)”). ) (Component (A1)) is preferred.
The component (A1) is a structural unit containing a lactone-containing cyclic group, a —SO ₂ —-containing cyclic group or a carbonate-containing cyclic group in addition to the structural unit (a1) (hereinafter referred to as “structural unit (a2)”. , And a structural unit containing a polar group-containing aliphatic hydrocarbon group (hereinafter, may be referred to as “structural unit (a3)”).

Structural unit (a1):
The structural unit (a1) is a structural unit containing an acid-decomposable group whose polarity increases due to the action of an acid.
The “acid-decomposable group” is a group having acid-decomposability capable of cleaving at least a part of the bonds in the structure of the acid-decomposable group by the action of an acid.
Examples of the acid-decomposable group whose polarity increases by the action of an acid include groups that decompose to form a polar group by the action of an acid.
Examples of the polar group include a carboxy group, a hydroxyl group, an amino group, a sulfo group _(-SO 3 H) and the like. Among these, a sulfo group or a polar group containing -OH in the structure (hereinafter sometimes referred to as "OH-containing polar group") is preferable, a sulfo group, a carboxy group or a hydroxyl group is preferable, and a carboxy group is particularly preferable. ..
Specific examples of the acid-decomposable group include groups in which the polar group is protected with an acid-dissociable group (for example, a group in which a hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).
Here, the "acid dissociable group" means
(I) an acid dissociable group capable of cleaving the bond between the acid dissociable group and an atom adjacent to the acid dissociable group by the action of an acid, or
(Ii) A group capable of cleaving the bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group by further decarboxylation reaction after a part of the bond is cleaved by the action of an acid. ,
To both sides.
The acid-dissociable group constituting the acid-decomposable group needs to be a group having a lower polarity than the polar group generated by dissociation of the acid-dissociable group. When is dissociated, a polar group having a higher polarity than the acid dissociable group is generated and the polarity is increased. As a result, the polarity of the entire component (A1) increases. The increase in polarity relatively changes the solubility in the developing solution, and decreases the solubility when the developing solution is an organic developing solution.

The acid dissociable group is not particularly limited, and those which have been proposed as the acid dissociable group of the base resin for the chemically amplified resist can be used.
Among the polar groups, examples of the acid dissociable group that protects a carboxy group or a hydroxyl group include, for example, an acid dissociable group represented by the following general formula (a1-r-1) (hereinafter, for convenience, "acetal-type acid dissociable group"). Sometimes referred to as "group").

［式中、Ｒａ’^１、Ｒａ’^２は水素原子またはアルキル基、Ｒａ’^３は炭化水素基、Ｒａ’^３は、Ｒａ’^１、Ｒａ’^２のいずれかと結合して環を形成してもよい。］

[In the formula, Ra′ ¹ and Ra′ ² are each a hydrogen atom or an alkyl group, Ra′ ³ is a hydrocarbon group, and Ra′ ³ is bonded to either Ra′ ¹ or Ra′ ² to form a ring. Good. ]

In the formula (a1-r-1), the alkyl group of Ra′ ¹ and Ra′ ² is mentioned as the substituent that may be bonded to the carbon atom at the α-position in the description of the α-substituted acrylate ester. Examples thereof include those similar to the alkyl group, a methyl group or an ethyl group is preferable, and a methyl group is most preferable.

As the hydrocarbon group for Ra′ ³ , an alkyl group having 1 to 20 carbon atoms is preferable, an alkyl group having 1 to 10 carbon atoms is more preferable; a linear or branched alkyl group is preferable, and specifically, , Methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, 1,1-dimethylethyl group, 1,1-diethylpropyl group 2,2-dimethylpropyl group, 2,2,-dimethylbutyl group and the like can be mentioned.

When Ra′ ³ is a cyclic hydrocarbon group, it may be aliphatic or aromatic, and may be polycyclic or monocyclic. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing one hydrogen atom from monocycloalkane. The monocycloalkane preferably has 3 to 8 carbon atoms, and specific examples thereof include cyclopentane, cyclohexane and cyclooctane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing one hydrogen atom from polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically, adamantane. , Norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.

When it becomes an aromatic hydrocarbon group, specific examples of the aromatic ring contained include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, phenanthrene; and the like of the carbon atoms constituting the aromatic hydrocarbon ring. Aromatic heterocycles partially substituted with heteroatoms; and the like. Examples of the hetero atom in the aromatic heterocycle include an oxygen atom, a sulfur atom and a nitrogen atom.
Specific examples of the aromatic hydrocarbon group include a group in which one hydrogen atom is removed from the aromatic hydrocarbon ring (aryl group); a group in which one of the hydrogen atoms in the aryl group is substituted with an alkylene group (for example, , Benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group and other arylalkyl groups); The alkylene group (alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

When Ra′ ³ is bonded to either Ra′ ¹ or Ra′ ² to form a ring, the cyclic group is preferably a 4- to 7-membered ring, more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

Among the polar groups, examples of the acid dissociable group that protects the carboxy group include acid dissociable groups represented by the following general formula (a1-r-2) (the following formula (a1-r-2). Among the acid dissociable groups represented by (4), those composed of an alkyl group may be hereinafter referred to as "tertiary alkyl ester type acid dissociable groups" for convenience).

［式中、Ｒａ’^４〜Ｒａ’^６は炭化水素基であり、Ｒａ’^５、Ｒａ’^６は互いに結合して環を形成してもよい。］

[In the formula, Ra′ ^{4 to} Ra′ ⁶ are hydrocarbon groups, and Ra′ ⁵ and Ra′ ⁶ may be bonded to each other to form a ring. ]

Examples of the hydrocarbon group for Ra′ ^{4 to} Ra′ ⁶ include the same as those for Ra′ ³ . Ra′ ⁴ is preferably an alkyl group having 1 to 5 carbon atoms. When Ra′ ⁵ and Ra′ ⁶ are bonded to each other to form a ring, a group represented by general formula (a1-r2-1) shown below can be mentioned.
On the other hand, when Ra′ ^{4 to} Ra′ ⁶ are not bonded to each other and are independent hydrocarbon groups, groups represented by general formula (a1-r2-2) shown below can be mentioned.

［式中、Ｒａ’^１０は炭素数１〜１０のアルキル基、Ｒａ’^１１はＲａ’^１０が結合した炭素原子と共に脂肪族環式基を形成する基、Ｒａ’^１２〜Ｒａ’^１４は、それぞれ独立に炭化水素基を示す。］

[In the formula, Ra′ ¹⁰ is an alkyl group having 1 to ¹⁰ carbon atoms, Ra′ ¹¹ is a group forming an aliphatic cyclic group together with the carbon atom to which Ra′ ¹⁰ is bonded, Ra′ ^{12 to} Ra′ ¹⁴ are respectively It independently represents a hydrocarbon group. ]

In the formula (a1-r2-1), the alkyl group of the alkyl group having 1 to ¹⁰ carbon atoms of Ra′ ¹⁰ is the linear or branched alkyl group of Ra′ ³ in the formula (a1-r-1). The groups mentioned as are preferable. In the formula (a1-r2-1), the aliphatic cyclic group which Ra′ ¹¹ constitutes is preferably the group exemplified as the cyclic alkyl group for Ra′ ³ in the formula (a1-r-1).

In formula (a1-r2-2), it is preferable that Ra′ ¹² and Ra′ ¹⁴ are each independently an alkyl group having 1 to 10 carbon atoms, and the alkyl group is Ra in formula (a1-r-1). The group described as the linear or branched alkyl group of ' ³ is more preferable, a linear alkyl group having 1 to 5 carbon atoms is further preferable, and a methyl group or an ethyl group is particularly preferable. ..
In formula (a1-r2-2), Ra′ ¹³ is a linear, branched or cyclic alkyl group exemplified as the hydrocarbon group for Ra′ ³ in formula (a1-r-1). Is preferred. Among these, the groups mentioned as the cyclic alkyl group of Ra′ ³ are more preferable.

Specific examples of the formula (a1-r2-1) will be given below. In the formulas below, “*” indicates a bond.

Specific examples of the formula (a1-r2-2) will be given below.

Moreover, as an acid dissociable group which protects a hydroxyl group among the polar groups, for example, an acid dissociable group represented by the following general formula (a1-r-3) (hereinafter, for the sake of convenience, "tertiary alkyloxycarbonyl acid") is used. Sometimes referred to as a “dissociative group”).

［式中、Ｒａ’^７〜Ｒａ’^９はアルキル基を示す。］

Wherein, Ra ^'7 ~Ra' ⁹ is an alkyl group. ]

In formula (a1-r-3), Ra′ ^{7 to} Ra′ ⁹ are preferably alkyl groups having 1 to 5 carbon atoms, and more preferably 1 to 3 carbon atoms.
The total carbon number of each alkyl group is preferably 3 to 7, more preferably 3 to 5, and most preferably 3 to 4.

The structural unit (a1) is a structural unit derived from an acrylate ester in which a hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, and an acid whose polarity increases by the action of an acid. A constitutional unit containing a decomposable group; a constitutional unit in which at least a part of hydrogen atoms in a hydroxyl group of the constitutional unit derived from hydroxystyrene or a hydroxystyrene derivative is protected by a substituent containing the acid-decomposable group; vinylbenzoic acid or Examples include a structural unit in which at least a part of hydrogen atoms in -C(=O)-OH of a structural unit derived from a vinylbenzoic acid derivative is protected by a substituent containing the acid-decomposable group.

Among the above, the structural unit (a1) is preferably a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent.
As the structural unit (a1), a structural unit represented by general formula (a1-1) or (a1-2) shown below is preferable.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基である。Ｖａ^１はエーテル結合、ウレタン結合、又はアミド結合を有していてもよい２価の炭化水素基であり、ｎ_ａ１は０〜２であり、Ｒａ^１は上記式（ａ１−ｒ−１）〜（ａ１−ｒ−２）で表される酸解離性基である。Ｗａ^１はｎ_ａ２＋１価の炭化水素基であり、ｎ_ａ２は１〜３であり、Ｒａ^２は上記式（ａ１−ｒ−１）または（ａ１−ｒ−３）で表される酸解離性基である。］

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Va ¹ is a divalent hydrocarbon group which may have an ether bond, a urethane bond, or an amide bond, na ₁ is 0 to 2, and Ra ¹ is the above formula (a1-r-1) to It is an acid dissociable group represented by (a1-r-2). Wa ¹ is a _{na 2} +1 valent hydrocarbon group, _{na 2} is 1 to 3, and Ra ² is an acid dissociable compound represented by the above formula (a1-r-1) or (a1-r-3). It is a base. ]

In the general formula (a1-1), the alkyl group having 1 to 5 carbon atoms is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, specifically, a methyl group, an ethyl group, Examples thereof include a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group and a neopentyl group. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which a part or all of hydrogen atoms of the alkyl group having 1 to 5 carbon atoms is substituted with a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is particularly preferable.
As R, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms is preferable, and a hydrogen atom or a methyl group is most preferable from the viewpoint of industrial availability.

In the formula (a1-1), the divalent hydrocarbon group for Va ¹ is the same as the description of the divalent hydrocarbon group for Vx ⁰¹ in the general formula (b1-u1).
The divalent hydrocarbon group in Va ¹ may have an ether bond, a urethane bond, or an amide bond.

In the formula (a1-2), the na ₂ +1 valent hydrocarbon group for Wa ¹ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity, may be saturated or unsaturated, and is usually preferably saturated. As the aliphatic hydrocarbon group, a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, or a linear or branched aliphatic hydrocarbon group Examples thereof include groups in which an aliphatic hydrocarbon group having a ring in the structure is combined, and specific examples thereof include the same groups as Va ¹ in the above formula (a1-1).
The _{na 2} +1 valence is preferably 2 to 4, and more preferably 2 or 3.

As the formula (a1-2), a structural unit represented by general formula (a1-2-01) shown below is particularly desirable.

In formula (a1-2-01), Ra ² is an acid dissociable group represented by the above formula (a1-r-1) or (a1-r-3). n _a2 is an integer of 1 to 3, preferably 1 or 2, and more preferably 1. c is an integer of 0 to 3, preferably 0 or 1, and more preferably 1. R is the same as above.

Specific examples of the above formulas (a1-1) and (a1-2) are shown below. In each of the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

The proportion of the structural unit (a1) in the component (A1) is preferably 20 to 80 mol%, more preferably 20 to 75 mol%, and even more preferably 25 to 70 mol%, based on all the structural units constituting the component (A1). Is more preferable. By setting the ratio of the structural unit (a1) to the lower limit or more, the lithography properties such as sensitivity, resolution and LWR are also improved. Further, by setting the content to the upper limit or less, it is possible to balance with other structural units.

Structural unit (a2):
The structural unit (a2) is a structural unit containing a lactone-containing cyclic group, a —SO ₂ — containing cyclic group or a carbonate containing cyclic group.
The lactone-containing cyclic group, -SO ₂ -containing cyclic group or carbonate-containing cyclic group of the structural unit (a2) adheres to the substrate of the resist film when the component (A1) is used for forming the resist film. It is effective in enhancing the sex.
In the present embodiment, the component (A1) preferably has the structural unit (a2).
When the structural unit (a1) contains a lactone-containing cyclic group, a —SO ₂ —-containing cyclic group or a carbonate-containing cyclic group in its structure, the structural unit also corresponds to the structural unit (a2). However, such a structural unit corresponds to the structural unit (a1) and does not correspond to the structural unit (a2).

The structural unit (a2) is preferably a structural unit represented by general formula (a2-1) shown below.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基であり、Ｙａ^２１は単結合または２価の連結基であり、Ｌａ^２１は−Ｏ−、−ＣＯＯ−、−ＣＯＮ（Ｒ’）−、−ＯＣＯ−、−ＣＯＮＨＣＯ−又は−ＣＯＮＨＣＳ−であり、Ｒ’は水素原子またはメチル基を示す。ただしＬａ^２１が−Ｏ−の場合、Ｙａ^２１は−ＣＯ−にはならない。Ｒａ^２１はラクトン含有環式基、−ＳＯ_２−含有環式基又はカーボネート含有環式基である。］

[In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, Ya ²¹ is a single bond or a divalent linking group, and La ²¹ is -O. -, -COO-, -CON(R')-, -OCO-, -CONHCO- or -CONHCS-, and R'represents a hydrogen atom or a methyl group. However, when La ²¹ is -O-, Ya ²¹ does not become -CO-. Ra ²¹ is a lactone-containing cyclic group, a —SO ₂ — containing cyclic group or a carbonate containing cyclic group. ]

The divalent linking group for Ya ²¹ is not particularly limited, but examples thereof include a divalent hydrocarbon group which may have a substituent and a divalent linking group containing a hetero atom. The divalent hydrocarbon group optionally having a substituent in Ya ^{21 and} the divalent linking group containing a hetero atom have a substituent in Yx ⁰¹ in the above formula (b1-u1), The same divalent hydrocarbon group and the same as the divalent linking group containing a hetero atom may be used.
In the present embodiment, as Ya ²¹ , a single bond, an ester bond [—C(═O)—O—], an ether bond (—O—), a linear or branched alkylene group, or a combination thereof. Is preferred.

The “lactone-containing cyclic group” refers to a cyclic group containing a ring (lactone ring) containing —O—C(═O)— in its ring skeleton. The lactone ring is counted as the first ring, and a lactone ring alone is referred to as a monocyclic group, and a lactone ring having another ring structure is referred to as a polycyclic group regardless of the structure. The lactone-containing cyclic group may be either a monocyclic group or a polycyclic group.
The lactone-containing cyclic group is not particularly limited and any one can be used. Specific examples include groups represented by general formulas (a2-r-1) to (a2-r-7) shown below. Hereinafter, “*” represents a bond.

［式中、Ｒａ’^２１はそれぞれ独立に水素原子、アルキル基、アルコキシ基、ハロゲン原子、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基またはシアノ基であり；Ｒ”は水素原子またはアルキル基であり；Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり、ｎ’は０〜２の整数であり、ｍ’は０または１である。］

[Wherein Ra′ ²¹ is independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR”, —OC(═O)R”, a hydroxyalkyl group or a cyano group. R" is a hydrogen atom or an alkyl group; A" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, and n'is 0 to 2 Is an integer and m′ is 0 or 1. ]

In the general formulas (a2-r-1) to (a2-r-7), A″ has 1 to 5 carbon atoms which may contain an oxygen atom (—O—) or a sulfur atom (—S—). And an oxygen atom or a sulfur atom. As the alkylene group having 1 to 5 carbon atoms in A″, a linear or branched alkylene group is preferable, and a methylene group, an ethylene group, an n-propylene group, Examples include isopropylene group and the like. When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include a group in which —O— or —S— is present at the terminal or carbon atom of the alkylene group, and for example, —O—CH _{2 -, - CH 2 -O-CH} 2 -, - S-CH 2 -, - CH 2 -S-CH 2 - , and the like. As A″, an alkylene group having 1 to 5 carbon atoms or —O— is preferable, an alkylene group having 1 to 5 carbon atoms is more preferable, and a methylene group is most preferable. Ra′ ²¹ is independently an alkyl group or an alkoxy group. A group, a halogen atom, a halogenated alkyl group, -COOR", -OC(=O)R", a hydroxyalkyl group or a cyano group.
The alkyl group in Ra′ ²¹ is preferably an alkyl group having 1 to 5 carbon atoms.
As the alkoxy group for Ra′ ^21, an alkoxy group having 1 to 6 carbon atoms is preferable. The alkoxy group is preferably linear or branched. Specific examples thereof include groups in which an alkyl group mentioned as the alkyl group in Ra′ ²¹ and an oxygen atom (—O—) are linked.
Examples of the halogen atom in Ra′ ²¹ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.
'Examples of the halogenated alkyl group for ^21, the Ra' Ra part or all of the hydrogen atoms of the alkyl group in ²¹ can be mentioned it has been substituted with the aforementioned halogen atoms. As the halogenated alkyl group, a fluorinated alkyl group is preferable, and a perfluoroalkyl group is particularly preferable.

Specific examples of the groups represented by general formulas (a2-r-1) to (a2-r-7) are shown below.

And _- "-SO 2 containing cyclic group", -SO 2 _- within the ring skeleton thereof shows a cyclic group containing a ring containing, in particular, -SO 2 _- sulfur atom (S) is in A cyclic group that forms part of the ring skeleton of the cyclic group. A ring containing —SO ₂ — in its ring skeleton is counted as the first ring, and if it is the only ring, it is a monocyclic group, and if it has another ring structure, it is a polycyclic group regardless of its structure. Called. The —SO ₂ — containing cyclic group may be monocyclic or polycyclic.
The —SO ₂ — containing cyclic group is particularly a cyclic group containing —O—SO ₂ — in its ring skeleton, that is, —O—S— in —O—SO ₂ — forms a part of the ring skeleton. It is preferably a cyclic group containing a sultone ring to be formed. Specific examples of the —SO ₂ — containing cyclic group include groups represented by general formulas (a5-r-1) to (a5-r-4) shown below.

［式中、Ｒａ’^５１はそれぞれ独立に水素原子、アルキル基、アルコキシ基、ハロゲン原子、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基またはシアノ基であり；Ｒ”は水素原子またはアルキル基であり；Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり、ｎ’は０〜２の整数である。］

[Wherein Ra′ ⁵¹ is independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group or a cyano group. R" is a hydrogen atom or an alkyl group; A" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, and n'is 0 to 2 Is an integer. ]

In the general formulas (a5-r-1) to (a5-r-4), A″ is the same as A″ in the general formulas (a2-r-1) to (a2-r-7) described above. .. Examples of the alkyl group, alkoxy group, halogen atom, halogenated alkyl group, —COOR″, —OC(═O)R″, and hydroxyalkyl group for Ra′ ⁵¹ are the above general formulas (a2-r-1) to ( The same as Ra' ^{21 in} a2-r-7).

Specific examples of the groups represented by general formulas (a5-r-1) to (a5-r-4) are shown below. “Ac” in the formula represents an acetyl group.

The “carbonate-containing cyclic group” refers to a cyclic group containing a ring (carbonate ring) containing —O—C(═O)—O— in its ring skeleton. The carbonate ring is counted as the first ring, and when it has only a carbonate ring, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of its structure. The carbonate-containing cyclic group may be either a monocyclic group or a polycyclic group.
The carbonate ring-containing cyclic group is not particularly limited, and any group can be used. Specific examples include groups represented by general formulas (ax3-r-1) to (ax3-r-3) shown below.

［式中、Ｒａ’^ｘ３１はそれぞれ独立に水素原子、アルキル基、アルコキシ基、ハロゲン原子、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基またはシアノ基であり；Ｒ”は水素原子またはアルキル基であり；Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり、ｐ’は０〜３の整数であり、ｑ’は０または１である。］

[ ^Wherein Ra′ ^x31 is independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, —COOR”, —OC(═O)R”, a hydroxyalkyl group or a cyano group. R" is a hydrogen atom or an alkyl group; A" is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, and p'is 0 to 3 Is an integer and q'is 0 or 1. ]

A" in the general formulas (ax3-r-1) to (ax3-r-3) is the same as A" in the general formula (a2-r-1).
The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, —COOR″, —OC(═O)R″, and hydroxyalkyl group for Ra′ ^x31 are each represented by the general formula (a2-r-1) to (a2-r-1). The same as those mentioned in the description of Ra′ ^{21 in} a2-r-7) can be mentioned.

Specific examples of the groups represented by general formulas (ax3-r-1) to (ax3-r-3) are shown below.

The structural unit (a2) contained in the component (A1) may be one type or two or more types.
When the component (A1) has the structural unit (a2), the proportion of the structural unit (a2) is preferably 1 to 80 mol% with respect to the total of all the structural units constituting the component (A1), It is more preferably from 5 to 70 mol%, further preferably from 10 to 65 mol%, particularly preferably from 10 to 60 mol%.
When the ratio of the structural unit (a2) is at least the lower limit value, the effect of containing the structural unit (a2) is sufficiently obtained, and when the ratio is at most the upper limit value, it is balanced with other structural units. Thus, various lithographic characteristics such as DOF and CDU and pattern shape are improved.

Structural unit (a3):
The structural unit (a3) is a structural unit containing a polar group-containing aliphatic hydrocarbon group (excluding those corresponding to the structural units (a1) and (a2) described above).
It is considered that the component (A1) having the structural unit (a3) increases the hydrophilicity of the component (A) and contributes to the improvement of resolution.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is replaced with a fluorine atom, and the like, and a hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and a cyclic aliphatic hydrocarbon group (cyclic group). The cyclic group may be a monocyclic group or a polycyclic group, and for example, it can be appropriately selected and used from the many proposed ones in resins for resist compositions for ArF excimer lasers. The cyclic group is preferably a polycyclic group, and more preferably has 7 to 30 carbon atoms.
Among them, a structural unit derived from an acrylate ester containing an aliphatic polycyclic group containing a hydroxyalkyl group in which a part of hydrogen atoms of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with a fluorine atom. Is more preferable. Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane, and the like. Specific examples thereof include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, a group obtained by removing two or more hydrogen atoms from adamantane, a group obtained by removing two or more hydrogen atoms from norbornane, and a group obtained by removing two or more hydrogen atoms from tetracyclododecane are Industrially preferred.

The structural unit (a3) is not particularly limited as long as it contains a polar group-containing aliphatic hydrocarbon group, and any unit can be used.
The structural unit (a3) is a structural unit derived from an acrylate ester in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent, and includes a polar group-containing aliphatic hydrocarbon group. Structural units are preferred.
As the structural unit (a3), when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms, it is derived from hydroxyethyl ester of acrylic acid. When the hydrocarbon group is a polycyclic group, a structural unit represented by the following formula (a3-1), a structural unit represented by the formula (a3-2), a formula (a3) The structural unit represented by a3-3) is preferred.

［式中、Ｒは前記と同じであり、ｊは１〜３の整数であり、ｋは１〜３の整数であり、ｔ’は１〜３の整数であり、ｌは１〜５の整数であり、ｓは１〜３の整数である。］

[In the formula, R is the same as above, j is an integer of 1 to 3, k is an integer of 1 to 3, t'is an integer of 1 to 3, and l is an integer of 1 to 5. And s is an integer of 1 to 3. ]

In the formula (a3-1), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl groups are bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group be bonded to the 3-position of the adamantyl group.
j is preferably 1, and particularly preferably a hydroxyl group bonded to the 3-position of the adamantyl group.

In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group.

In formula (a3-3), t′ is preferably 1. It is preferable that l is 1. It is preferable that s is 1. These preferably have a 2-norbornyl group or a 3-norbornyl group bonded to the terminal of the carboxy group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

The structural unit (a3) contained in the component (A1) may be one type or two or more types.
When the component (A1) has the structural unit (a3), the proportion of the structural unit (a3) is preferably 5 to 50 mol% with respect to the total of all the structural units constituting the component (A1), 5 to 40 mol% is more preferable, and 5 to 25 mol% is further preferable.
By setting the ratio of the structural unit (a3) to the lower limit or more, the effect of containing the structural unit (a3) can be sufficiently obtained, and by setting the ratio of the structural unit (a3) to the upper limit or less, balance with other structural units can be achieved. It will be easier.

The component (A1) may have the following structural unit (a4) in addition to the above structural units (a1), (a2) and (a3).

Structural unit (a4):
The structural unit (a4) is a structural unit containing an acid non-dissociable cyclic group. When the component (A1) has the structural unit (a4), the dry etching resistance of the resist pattern formed is improved. Further, the hydrophobicity of the component (A1) is increased. It is considered that the improvement of hydrophobicity contributes to the improvement of resolution, resist pattern shape, etc., particularly in the case of organic solvent development.
The “acid-non-dissociable cyclic group” in the structural unit (a4) means that when an acid is generated from the component (B) described below by exposure, it does not dissociate in the structural unit as it is even when the acid acts. It is the remaining cyclic group.
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing an acid non-dissociable aliphatic cyclic group is preferable. Examples of the cyclic group include the same groups as those exemplified in the case of the structural unit (a1), for ArF excimer laser, KrF excimer laser (preferably for ArF excimer laser), etc. A large number of those conventionally known as those used as the resin component of the resist composition can be used.
Particularly, at least one selected from a tricyclodecyl group, an adamantyl group, a tetracyclododecyl group, an isobornyl group, and a norbornyl group is preferable in terms of industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include those represented by general formulas (a4-1) to (a4-7) shown below.

［式中、Ｒ^αは、水素原子、メチル基またはトリフルオロメチル基を示す。］

[In the formula, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group. ]

The structural unit (a4) contained in the component (A1) may be one type or two or more types.
When the component (A1) has the structural unit (a4), the proportion of the structural unit (a4) is preferably 1 to 30 mol% with respect to the total of all the structural units constituting the component (A1). It is more preferably about 20 mol%.

The component (A1) is particularly preferably a copolymer having (a1), (a2) and (a3).

The component (A1) is obtained by polymerizing a monomer that induces each structural unit, for example, by known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate. be able to.
Further, as the component (A1), a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C(CF ₃ ) ₂ —OH is used in combination during the above polymerization, so that -C and _{(CF 3)} 2 -OH group may be introduced into the. As described above, the copolymer having a hydroxyalkyl group in which a part of hydrogen atoms of the alkyl group is substituted with a fluorine atom is introduced, the development defects are reduced and LER (line edge roughness: unevenness of line side wall unevenness) is obtained. Is effective in reducing

In the present embodiment, the weight average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography) of the component (A1) is not particularly limited and is preferably 1000 to 50000, more preferably 1500 to 30000, 2000-20000 is the most preferable.
When it is at most the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and when it is at least the lower limit of this range, dry etching resistance and resist pre-pattern cross-sectional shape are good. ..

In the resist composition, as the component (A1), one type may be used alone, or two or more types may be used in combination.
The proportion of the component (A1) in the base component (A) is preferably 25% by mass or more, more preferably 50% by mass, further preferably 75% by mass, based on the total mass of the substrate component (A). It may be% by mass. When the proportion is 25% by mass or more, the lithography characteristics are further improved.

In the resist composition, as the component (A), one type may be used alone, or two or more types may be used in combination.
In the present embodiment, the content of the component (A) may be adjusted according to the resist film thickness to be formed and the like.

<<Acid Generator Component; (B) Component>>
In the present embodiment, the resist composition may contain an acid generator component (B) that generates an acid upon exposure (hereinafter referred to as “(B) component”).
The component (B) is not particularly limited, and those which have been proposed as acid generators for chemically amplified resists can be used.
Examples of such an acid generator include onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators, diazomethane-based acid generators such as bisalkyl or bisarylsulfonyldiazomethanes and poly(bissulfonyl)diazomethanes. There are various types such as an acid generator, a nitrobenzyl sulfonate-based acid generator, an imino sulfonate-based acid generator, and a disulfone-based acid generator. Among these, it is preferable to use an onium salt-based acid generator.

Examples of the onium salt-based acid generator include a compound represented by the following general formula (b-1) (hereinafter also referred to as “component (b-1)”) and a general formula (b-2). A compound (hereinafter also referred to as “component (b-2)”) or a compound represented by general formula (b-3) (hereinafter also referred to as “(b-3) component”) can be used.

［式中、Ｒ^１０１、Ｒ^１０４〜Ｒ^１０８はそれぞれ独立に置換基を有していてもよい環式基、置換基を有していてもよい鎖状のアルキル基、または置換基を有していてもよい鎖状のアルケニル基である。Ｒ^１０４、Ｒ^１０５は、相互に結合して環を形成していてもよい。Ｒ^１０６〜Ｒ^１０７のいずれか２つは、相互に結合して環を形成していてもよい。Ｒ^１０２はフッ素原子または炭素数１〜５のフッ素化アルキル基である。Ｙ^１０１は単結合または酸素原子を含む２価の連結基である。Ｖ^１０１〜Ｖ^１０３はそれぞれ独立に単結合、アルキレン基、またはフッ素化アルキレン基である。Ｌ^１０１〜Ｌ^１０２はそれぞれ独立に単結合または酸素原子である。Ｌ^１０３〜Ｌ^１０５はそれぞれ独立に単結合、−ＣＯ−又は−ＳＯ_２−である。Ｍ’^ｍ＋はｍ価の有機カチオンである。］

[In formula, R< ¹⁰¹ >, R< ¹⁰⁴ >-R< ¹⁰⁸ > has a cyclic group which may have a substituent each independently, the chain-like alkyl group which may have a substituent, or a substituent. A chain alkenyl group which may be present. R ¹⁰⁴ and R ¹⁰⁵ may be bonded to each other to form a ring. Any two of R ^{106 to} R ¹⁰⁷ may be bonded to each other to form a ring. R ¹⁰² is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. Y ¹⁰¹ is a single bond or a divalent linking group containing an oxygen atom. V ^{101 to} V ¹⁰³ are each independently a single bond, an alkylene group, or a fluorinated alkylene group. L ^{101 to} L ¹⁰² are each independently a single bond or an oxygen atom. L ^{103 to} L ¹⁰⁵ are each independently a single bond, —CO— or —SO ₂ —. ^M'm+ is an m-valent organic cation. ]

{Anion part}
Anion part of component (b-1) In formula (b-1), R ¹⁰¹ represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, Alternatively, it is a chain alkenyl group which may have a substituent.

.. Cyclic group which may have a substituent in R ¹⁰¹ The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group is an aromatic hydrocarbon group. Or may be an aliphatic hydrocarbon group.
The aromatic hydrocarbon group for R ¹⁰¹ is an aromatic hydrocarbon ring mentioned as the divalent aromatic hydrocarbon group for Vx ⁰¹ in the formula (b1-u1), or an aromatic compound containing two or more aromatic rings. And an aryl group obtained by removing one hydrogen atom from the above, and a phenyl group and a naphthyl group are preferable.
The cyclic aliphatic hydrocarbon group for R ¹⁰¹ is obtained by removing one hydrogen atom from the monocycloalkane or polycycloalkane mentioned as the divalent aliphatic hydrocarbon group for Vx ⁰¹ in the formula (b1-u1). Examples thereof include an adamantyl group and a norbornyl group.
The cyclic hydrocarbon group for R ¹⁰¹ may contain a heteroatom such as a heterocycle, and is specifically represented by any of the above general formulas (a2-r-1) to (a2-r-7). The lactone-containing cyclic group, the -SO ₂ -containing cyclic group respectively represented by the above general formulas (a5-r-1) to (a5-r-4), and the following (r-hr-1) to The heterocyclic group mentioned in (r-hr-16) can be mentioned.

Examples of the substituent in the cyclic hydrocarbon group of R ¹⁰¹ include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group and the like.
The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group or a tert-butyl group.
The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, a tert-butoxy group, and a methoxy group. Most preferred is the group ethoxy.
Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.
As the halogenated alkyl group as a substituent, some or all of hydrogen atoms such as an alkyl group having 1 to 5 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group are the above Examples thereof include groups substituted with a halogen atom.

· The chain alkyl group of the alkyl group R ¹⁰¹ may be chain substituted in R ^101, may be either linear or branched.
The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group. Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, henicosyl group, docosyl group and the like.
The branched chain alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like can be mentioned.

The chain alkenyl group of alkenyl group R ¹⁰¹ may be chain substituted in · · R ^101, may be either linear or branched, is 2-10 carbon atoms It is preferable, 2-5 is more preferable, 2-4 is more preferable, and 3 is particularly preferable. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group) and a butynyl group. Examples of the branched alkenyl group include a 1-methylpropenyl group and a 2-methylpropenyl group.
Among the above, the chain alkenyl group is particularly preferably a propenyl group.

Examples of the substituent in the chain alkyl group or alkenyl group for R ¹⁰¹ include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, and the cyclic group for R ¹⁰¹ above. Can be mentioned.

Among them, R ¹⁰¹ is preferably a cyclic group which may have a substituent, and more preferably a cyclic hydrocarbon group which may have a substituent. More specifically, a phenyl group, a naphthyl group, a group obtained by removing one or more hydrogen atoms from a polycycloalkane, and a lactone represented by each of the formulas (a2-r-1) to (a2-r-7). Preferred are a containing cyclic group and a —SO ₂ — containing cyclic group represented by each of the above general formulas (a5-r-1) to (a5-r-4).

In formula (b-1), Y ¹⁰¹ is a single bond or a divalent linking group containing an oxygen atom.
When Y ¹⁰¹ is a divalent linking group containing an oxygen atom, Y ¹⁰¹ may contain an atom other than an oxygen atom. Examples of the atom other than the oxygen atom include a carbon atom, a hydrogen atom, a sulfur atom and a nitrogen atom.
Examples of the divalent linking group containing an oxygen atom include an oxygen atom (ether bond: —O—), an ester bond (—C(═O)—O—), an oxycarbonyl group (—O—C(═O). )-), amide bond (-C(=O)-NH-), carbonyl group (-C(=O)-), carbonate bond (-O-C(=O)-O-) and other non-hydrocarbons. Examples include a combination of a non-hydrocarbon-based oxygen atom-containing linking group and an alkylene group. A sulfonyl group (—SO ₂ —) may be further linked to the combination. Examples of the combination include linking groups represented by the following formulas (y-al-1) to (y-al-7).

［式中、Ｖ’^１０１は単結合または炭素数１〜５のアルキレン基であり、Ｖ’^１０２は炭素数１〜３０の２価の飽和炭化水素基である。］

[In the formula, V′ ¹⁰¹ is a single bond or an alkylene group having 1 to 5 carbon atoms, and V′ ¹⁰² is a divalent saturated hydrocarbon group having 1 to 30 carbon atoms. ]

The divalent saturated hydrocarbon group for V′ ¹⁰² is preferably an alkylene group having 1 to 30 carbon atoms.

The alkylene group in V′ ¹⁰¹ and V′ ¹⁰² may be a linear alkylene group or a branched alkylene group, and a linear alkylene group is preferable.
As the alkylene group for V′ ¹⁰¹ and V′ ¹⁰² , specifically, a methylene group [—CH ₂ —]; —CH(CH ₃ )—, —CH(CH ₂ CH ₃ )—, and —C(CH ₃ ). _{2 -, - C (CH 3} ) (CH 2 CH 3) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as ethylene group _{[-CH 2 CH 2 -];} - CH (CH 3) CH 2 -, - CH (CH 3) CH (CH 3) -, - C (CH 3) 2 CH 2 -, - CH (CH 2 CH ₃ ) Alkyl ethylene group such as CH ₂ -; trimethylene group (n-propylene group) [-CH ₂ CH ₂ CH ₂ -]; -CH(CH ₃ )CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ ). tetramethylene group _{[-CH 2 CH 2 CH 2 CH} 2 -];; - CH 2 alkyltetramethylene groups such as _{- CH (CH 3) CH 2} CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH ₂ - and the like alkyl tetramethylene group; pentamethylene group _{[-CH 2 CH 2 CH 2 CH} 2 CH 2 -] , and the like.
Moreover, a part of the methylene groups in the alkylene group in V′ ¹⁰¹ or V′ ¹⁰² may be substituted with a divalent aliphatic cyclic group having 5 to 10 carbon atoms. The aliphatic cyclic group is preferably a divalent group obtained by further removing one hydrogen atom from the cyclic aliphatic hydrocarbon group of Ra′ ^{3 in} the above formula (a1-r-1), and a cyclohexylene group. , 1,5-adamantylene group or 2,6-adamantylene group is more preferred.

As Y ¹⁰¹ , a divalent linking group having an ester bond or an ether bond is preferable, and a linking group represented by each of the above formulas (y-al-1) to (y-al-5) is preferable.

In formula (b-1), V ¹⁰¹ is a single bond, an alkylene group, or a fluorinated alkylene group. The alkylene group and fluorinated alkylene group for V ¹⁰¹ preferably have 1 to 4 carbon atoms. ^Examples of the fluorinated alkylene group for V ¹⁰¹ include groups in which some or all of the hydrogen atoms of the alkylene group for V ¹⁰¹ have been replaced with fluorine atoms. Among them, V ¹⁰¹ is preferably a single bond or a fluorinated alkylene group having 1 to 4 carbon atoms.

In formula (b-1), R ¹⁰² is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. R ¹⁰² is preferably a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms, and more preferably a fluorine atom.

(B-1) Specific examples of the anion moiety of the component, for example, if the Y ¹⁰¹ is a single bond, fluorinated alkyl sulfonate anions such as trifluoromethane sulfonate anion or perfluorobutane sulfonate anion can be exemplified; Y ¹⁰¹ is In the case of a divalent linking group containing an oxygen atom, an anion represented by any of the following formulas (an-1) to (an-3) can be mentioned.

［式中、Ｒ”^１０１は、置換基を有していてもよい脂肪族環式基、前記式（ｒ−ｈｒ−１）〜（ｒ−ｈｒ−６）でそれぞれ表される基、又は置換基を有していてもよい鎖状のアルキル基であり；Ｒ”^１０２は、置換基を有していてもよい脂肪族環式基、前記式（ａ２−ｒ−１）〜（ａ２−ｒ−７）でそれぞれ表されるラクトン含有環式基、又は前記一般式（ａ５−ｒ−１）〜（ａ５−ｒ−４）でそれぞれ表される−ＳＯ_２−含有環式基であり；Ｒ”^１０３は、置換基を有していてもよい芳香族環式基、置換基を有していてもよい脂肪族環式基、又は置換基を有していてもよい鎖状のアルケニル基であり；Ｖ”^１０１は、フッ素化アルキレン基であり；Ｌ”^１０１は、−Ｃ（＝Ｏ）−又は−ＳＯ_２−であり；ｖ”はそれぞれ独立に０〜３の整数であり、ｑ”はそれぞれ独立に１〜２０の整数であり、ｎ”は０または１である。］

[In the formula, R" ¹⁰¹ is an aliphatic cyclic group which may have a substituent, a group represented by each of the formulas (r-hr-1) to (r-hr-6), or a substituent. Is a chain alkyl group which may have a group; R″ ¹⁰² is an aliphatic cyclic group which may have a substituent, and the above formulas (a2-r-1) to (a2-r) lactone-containing cyclic group represented respectively by -7), or the formula (a5-r-1) ~ (a5-r-4) with -SO ₂ respectively represented - be-containing cyclic group; R “ ¹⁰³ is an aromatic cyclic group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain alkenyl group which may have a substituent. Yes; V″ ¹⁰¹ is a fluorinated alkylene group; L″ ¹⁰¹ is —C(═O)— or —SO ₂ —; v″ is each independently an integer of 0 to 3; Are each independently an integer of 1 to 20, and n″ is 0 or 1. ]

The aliphatic cyclic group which may have a substituent of R″ ¹⁰¹ , R″ ¹⁰² and R″ ¹⁰³ is preferably the group exemplified as the cyclic aliphatic hydrocarbon group for R ¹⁰¹ . Examples of the substituent include those similar to the substituent that may substitute the cyclic aliphatic hydrocarbon group for R ¹⁰¹ .

The aromatic cyclic group which may have a substituent in R″ ¹⁰³ is preferably the group exemplified as the aromatic hydrocarbon group in the cyclic hydrocarbon group in R ^101. The substituent is , R ¹⁰¹ may be the same as the substituent which may substitute the aromatic hydrocarbon group.

The chain alkyl group which may have a substituent in R″ ¹⁰¹ is preferably the group exemplified as the chain alkyl group in the above R ^101. The chain alkyl group which may have a substituent in R″ ¹⁰³ The chain alkenyl group which may be mentioned is preferably the group exemplified as the chain alkenyl group for R ¹⁰¹ . V″ ¹⁰¹ is preferably a fluorinated alkylene group having 1 to 3 carbon atoms, and particularly preferably —CF ₂ —, —CF ₂ CF ₂ —, —CHFCF ₂ —, and —CF(CF ₃ )CF ₂ —. _{, -CH (CF 3) CF 2} - it is.

Anion Part of Component (b-2) In Formula (b-2), R ¹⁰⁴ and R ¹⁰⁵ each independently have a cyclic group which may have a substituent or a substituent which may have a substituent. It is a good chain alkyl group or a chain alkenyl group which may have a substituent, and examples thereof include the same groups as R ¹⁰¹ in the formula (b-1). However, R ¹⁰⁴ and R ¹⁰⁵ may be bonded to each other to form a ring.
Each of R ¹⁰⁴ and R ¹⁰⁵ is preferably a chain alkyl group which may have a substituent, and is a linear or branched alkyl group or a linear or branched fluorinated alkyl group. Is more preferable.
The chain-like alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 7 carbon atoms, and further preferably 1 to 3 carbon atoms. The carbon number of the chain alkyl group of R ¹⁰⁴ and R ¹⁰⁵ is preferably as small as possible within the range of the above carbon number for the reason that solubility in the resist solvent is also good. Further, in the chain alkyl group of R ¹⁰⁴ and R ¹⁰⁵ , as the number of hydrogen atoms substituted with fluorine atoms is larger, the strength of the acid is stronger, and the high energy light of 200 nm or less and electron beam It is preferable because the transparency is improved. The ratio of fluorine atoms in the chain alkyl group, that is, the fluorination ratio is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all hydrogen atoms are replaced with fluorine atoms. It is a perfluoroalkyl group.
In formula (b-2), V ¹⁰² and V ¹⁰³ each independently represent a single bond, an alkylene group, or a fluorinated alkylene group, and each of them is the same as V ¹⁰¹ in formula (b-1). Can be mentioned.
In formula (b-2), L ^{101 to} L ¹⁰² each independently represent a single bond or an oxygen atom.

-Anion part of component (b-3) In formula (b-3), R< ¹⁰⁶ > to R< ¹⁰⁸ > may each independently have a cyclic group which may have a substituent, or a substituent which may have a substituent. It is a good chain alkyl group or a chain alkenyl group which may have a substituent, and examples thereof include the same groups as R ¹⁰¹ in the formula (b-1).
L ^{103 to} L ¹⁰⁵ are each independently a single bond, —CO— or —SO ₂ —.

{Cation part}
In the formulas (b-1), (b-2) and (b-3), ^M'm+ is an m-valent organic cation, preferably a sulfonium cation or an iodonium cation, and the following general formula The cations represented by (ca-1) to (ca-4) are particularly preferable.

［式中、Ｒ^２０１〜Ｒ^２０７、およびＲ^２１１〜Ｒ^２１２は、それぞれ独立に置換基を有していてもよいアリール基、アルキル基またはアルケニル基を表し、Ｒ^２０１〜Ｒ^２０３、Ｒ^２０６〜Ｒ^２０７、Ｒ^２１１〜Ｒ^２１２は、相互に結合して式中のイオウ原子と共に環を形成してもよい。Ｒ^２０８〜Ｒ^２０９はそれぞれ独立に水素原子または炭素数１〜５のアルキル基を表し、Ｒ^２１０は置換基を有していてもよいアリール基、アルキル基、アルケニル基、又は−ＳＯ_２−含有環式基であり、Ｌ^２０１は−Ｃ（＝Ｏ）−または−Ｃ（＝Ｏ）−Ｏ−を表し、Ｙ^２０１は、それぞれ独立に、アリーレン基、アルキレン基またはアルケニレン基を表し、ｘは１または２であり、Ｗ^２０１は（ｘ＋１）価の連結基を表す。］

[In the formula, R ^{201 to} R ²⁰⁷ and R ^{211 to} R ²¹² each independently represent an aryl group, an alkyl group or an alkenyl group which may have a substituent, and R ^{201 to} R ²⁰³ and R ²⁰⁶ to R ²⁰⁷ and R ^{211 to} R ²¹² may be bonded to each other to form a ring with the sulfur atom in the formula. R ^{208 to} R ²⁰⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ²¹⁰ is an aryl group which may have a substituent, an alkyl group, an alkenyl group, or —SO ₂ — containing. a cyclic ^{group, L 201} is -C (= O) - or -C (= O) represents ^{-O-, Y 201} each independently represent an arylene group, an alkylene group or alkenylene group, x 1 or 2 and W ²⁰¹ represents a (x+1)-valent linking group. ]

Examples of the aryl group in R ^{201 to} R ²⁰⁷ and R ^{211 to} R ²¹² include an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group and a naphthyl group are preferable.
The alkyl group in R ^{201 to} R ²⁰⁷ and R ^{211 to} R ²¹² is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms.
The alkenyl group for R ^{201 to} R ²⁰⁷ and R ^{211 to} R ²¹² preferably has 2 to 10 carbon atoms.
Examples of the substituent that R ^{201 to} R ²⁰⁷ and R ^{210 to} R ²¹² may have include, for example, an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and arylthio. And a group represented by each of the following formulas (ca-r-1) to (ca-r-7).
The aryl group in the arylthio group as a substituent is the same as that described for R ¹⁰¹ , and specifically includes a phenylthio group or a biphenylthio group.

［式中、Ｒ’^２０１はそれぞれ独立に、水素原子、置換基を有していてもよい環式基、鎖状のアルキル基、または鎖状のアルケニル基である。］

[In the formula, each R′ ²⁰¹ is independently a hydrogen atom, a cyclic group which may have a substituent, a chain alkyl group, or a chain alkenyl group. ]

The cyclic group which may have a substituent, the chain alkyl group which may have a substituent, or the chain alkenyl group which may have a substituent of R′ ²⁰¹ is as defined above. In addition to those similar to R ¹⁰¹ in the formula (b-1), a cyclic group which may have a substituent or a chain alkyl group which may have a substituent may be the above formula ( The same groups as the acid dissociable group represented by a1-r-2) are also included.

When R ^{201 to} R ²⁰³ , R ^{206 to} R ²⁰⁷ , and R ^{211 to} R ²¹² are bonded to each other to form a ring with a sulfur atom in the formula, a hetero atom such as a sulfur atom, an oxygen atom, or a nitrogen atom, or carbonyl _{group, -SO -, - SO 2 -} , - SO 3 -, - COO -, - CONH- , or -N _(R N) - (. the _{R N} is an alkyl group having 1 to 5 carbon atoms), etc. You may couple|bond together via the functional group of. As the ring to be formed, one ring containing a sulfur atom in the formula in its ring skeleton is preferably a 3 to 10-membered ring including a sulfur atom, and particularly preferably a 5 to 7-membered ring. preferable. Specific examples of the ring formed include, for example, thiophene ring, thiazole ring, benzothiophene ring, thianthrene ring, benzothiophene ring, dibenzothiophene ring, 9H-thioxanthene ring, thioxanthone ring, thianthrene ring, phenoxathiin ring, tetrahydro. Examples thereof include a thiophenium ring and a tetrahydrothiopyranium ring.

R ^{208 to} R ²⁰⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when they become an alkyl group, they are bonded to each other to form a ring. May be formed.

R ²¹⁰ may have an aryl group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or an substituent. -SO ₂ - containing cyclic group.
^Examples of the aryl group for R ²¹⁰ include an unsubstituted aryl group having 6 to 20 carbon atoms, and a phenyl group and a naphthyl group are preferable.
The alkyl group for R ²¹⁰ is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms.
The alkenyl group for R ²¹⁰ preferably has 2 to 10 carbon atoms.
Examples of the —SO ₂ — containing cyclic group which may have a substituent in R ²¹⁰ include the same ones as the above-mentioned “—SO ₂ — containing cyclic group”, and the above general formula (a5- The group represented by r-1) is preferable.

Y ^201's each independently represent an arylene group, an alkylene group or an alkenylene group.
Examples of the arylene group for Y ²⁰¹ include a group obtained by removing one hydrogen atom from the aryl group exemplified as the aromatic hydrocarbon group for R ¹⁰¹ in the above formula (b-1).
Examples of the alkylene group and alkenylene group for Y ²⁰¹ include the same ones as the aliphatic hydrocarbon group as the divalent hydrocarbon group for Vx ⁰¹ in the general formula (b1-u1).

In the formula (ca-4), x is 1 or 2.
W ²⁰¹ is a (x+1)-valent, that is, a divalent or trivalent linking group.
The divalent linking group for W ²⁰¹ is preferably a divalent hydrocarbon group which may have a substituent, and examples thereof include the same hydrocarbon group as Ya ²¹ in the general formula (a2-1). The divalent linking group for W ²⁰¹ may be linear, branched, or cyclic, and is preferably cyclic. Of these, a group in which two carbonyl groups are combined at both ends of the arylene group is preferable. Examples of the arylene group include a phenylene group and a naphthylene group, and a phenylene group is particularly preferable.
^Examples of the trivalent linking group for W ²⁰¹ include a group obtained by removing one hydrogen atom from the divalent linking group for W ²⁰¹ , a group in which the divalent linking group is further bonded to the divalent linking group, and the like. Can be mentioned. The trivalent linking group for W ²⁰¹ is preferably a group in which two carbonyl groups are bonded to an arylene group.

Specific examples of the suitable cation represented by the formula (ca-1) include cations represented by the following formulas (ca-1-1) to (ca-1-63).

［式中、ｇ１、ｇ２、ｇ３は繰返し数を示し、ｇ１は１〜５の整数であり、ｇ２は０〜２０の整数であり、ｇ３は０〜２０の整数である。］

[In formula, g1, g2, and g3 show a repeating number, g1 is an integer of 1-5, g2 is an integer of 0-20, and g3 is an integer of 0-20. ]

［式中、Ｒ”^２０１は水素原子又は置換基であって、置換基としては前記Ｒ^２０１〜Ｒ^２０７、およびＲ^２１０〜Ｒ^２１２が有していてもよい置換基として挙げたものと同様である。］

[In the formula, R″ ²⁰¹ is a hydrogen atom or a substituent, and the substituent is the same as those mentioned as the substituent which R ^{201 to} R ²⁰⁷ and R ^{210 to} R ²¹² may have. is there.]

Specific examples of the suitable cation represented by the formula (ca-3) include cations represented by the following formulas (ca-3-1) to (ca-3-6).

Specific examples of the suitable cation represented by the formula (ca-4) include cations represented by the following formulas (ca-4-1) to (ca-4-2).

As the component (B), one type of the above-mentioned acid generator may be used alone, or two or more types may be used in combination.
In the present embodiment, when the resist composition contains the component (B), the content of the component (B) is preferably 0.5 to 60 parts by mass, and 1 to 50 parts by mass with respect to 100 parts by mass of the component (A). Parts is more preferred, and 1-40 parts by mass is even more preferred.
By setting the content of the component (B) within the above range, pattern formation is sufficiently performed. Further, when each component of the resist composition is dissolved in an organic solvent, a uniform solution is obtained, and the storage stability becomes favorable, which is preferable.

<<Basic Compound Component; (D) Component>>
In the present embodiment, the resist composition further comprises, in addition to the component (A), or in addition to the components (A) and (B), an acid diffusion controller component (hereinafter also referred to as “component (D)”). May be included.
The component (D) acts as a quencher (acid diffusion control agent) that traps the acid generated by exposure from the component (B) and the like.
The component (D) in the present embodiment may be a photodegradable base (D1) which is decomposed by exposure and loses acid diffusion controllability (hereinafter referred to as “(D1) component”). The nitrogen-containing organic compound (D2) (hereinafter referred to as “(D2) component”) which does not correspond to the above may be used.

(D1) component:
By using the resist composition containing the component (D1), it is possible to improve the contrast between the exposed portion and the non-exposed portion when forming a resist pattern.
The component (D1) is not particularly limited as long as it decomposes by exposure and loses the acid diffusion controllability, and is a compound represented by the following general formula (d1-1) (hereinafter referred to as “(d1-1) component”). ), a compound represented by the following general formula (d1-2) (hereinafter referred to as “(d1-2) component”) and a compound represented by the following general formula (d1-3) (hereinafter referred to as “(d1- 3) component"). One or more compounds selected from the group consisting of) are preferable.
The components (d1-1) to (d1-3) do not act as a quencher because they decompose in the exposed area and lose the acid diffusion controllability (basicity), but act as a quencher in the unexposed area.

［式中、Ｒｄ^１〜Ｒｄ^４は置換基を有していてもよい環式基、置換基を有していてもよい鎖状のアルキル基、または置換基を有していてもよい鎖状のアルケニル基である。ただし、式（ｄ１−２）中のＲｄ^２における、Ｓ原子に隣接する炭素原子にはフッ素原子は結合していないものとする。Ｙｄ^１は単結合、または２価の連結基である。Ｍ^ｍ＋はそれぞれ独立にｍ価の有機カチオンである。］

[In the formula, Rd ^{1 to} Rd ⁴ are each a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain which may have a substituent. Is an alkenyl group of. However, a fluorine atom is not bonded to the carbon atom adjacent to the S atom in Rd ² in formula (d1-2). Yd ¹ is a single bond or a divalent linking group. M ^m+ is each independently an m-valent organic cation. ]

{(D1-1) component}
Anion moiety In the formula (d1-1), Rd ¹ has a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a substituent. Is a chain alkenyl group which may be the same as R ¹⁰¹ .
Among these, Rd ¹ may have an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a substituent. A chain hydrocarbon group is preferred. The substituent which these groups may have is preferably a hydroxyl group, a fluorine atom or a fluorinated alkyl group.
The aromatic hydrocarbon group is more preferably a phenyl group or a naphthyl group.
The aliphatic cyclic group is more preferably a group obtained by removing one or more hydrogen atoms from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane and tetracyclododecane.
The chain hydrocarbon group is preferably a chain alkyl group. The chain alkyl group preferably has 1 to 10 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group and a nonyl group. Group, linear alkyl group such as decyl group; 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group A branched chain alkyl group such as a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group and a 4-methylpentyl group.

When the chain alkyl group is a fluorinated alkyl group having a fluorine atom or a fluorinated alkyl group as a substituent, the carbon number of the fluorinated alkyl group is preferably 1 to 11, more preferably 1 to 8 and 1 The fluorinated alkyl group with 4 to 4 being more preferable may contain an atom other than a fluorine atom. Examples of the atom other than the fluorine atom include an oxygen atom, a carbon atom, a hydrogen atom, a sulfur atom and a nitrogen atom.
Rd ¹ is preferably a fluorinated alkyl group in which a part or all of hydrogen atoms constituting a linear alkyl group are substituted with a fluorine atom, and a hydrogen atom constituting a linear alkyl group is preferable. It is preferable that all are fluorinated alkyl groups (linear perfluoroalkyl groups) substituted with fluorine atoms.

Preferred specific examples of the anion moiety of the component (d1-1) are shown below.

-Cation part In formula (d1-1), Mm ⁺ is an m-valent organic cation.
The organic cation of M ^m+ is not particularly limited, and examples thereof include those similar to the cations represented by the general formulas (ca-1) to (ca-4), respectively. Cations represented by 1) to (ca-1-63) are preferable.
As the component (d1-1), one type may be used alone, or two or more types may be used in combination.

{(D1-2) component}
· During anion formula (d1-2), Rd ² is has an optionally substituted cyclic group which may have a substituent chain alkyl group or a substituted group, It may be a chain alkenyl group, and examples thereof include those similar to R ¹⁰¹ .
However, a fluorine atom is not bonded to the carbon atom adjacent to the S atom in Rd ² (not fluorine-substituted). Thereby, the anion of the component (d1-2) becomes an appropriate weak acid anion, and the quenching ability of the component (D) is improved.
Rd ² is preferably an aliphatic cyclic group which may have a substituent, and is a group obtained by removing one or more hydrogen atoms from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane and the like. (It may have a substituent); More preferably, it is a group obtained by removing one or more hydrogen atoms from camphor or the like.
The hydrocarbon group of Rd ² may have a substituent, and as the substituent, the hydrocarbon group in Rd ¹ of the formula (d1-1) (aromatic hydrocarbon group, aliphatic hydrocarbon group) The same as the substituent which may have.

Specific preferred examples of the anion moiety of the component (d1-2) are shown below.

-Cation part In formula (d1-2), Mm ⁺ is an m-valent organic cation and is the same as Mm ⁺ in the formula (d1-1).
As the component (d1-2), one type may be used alone, or two or more types may be used in combination.

{(D1-3) component}
During Anion formula (d1-3), Rd ³ is have an optionally substituted cyclic group which may have a substituent chain alkyl group or a substituted group, Is a chain alkenyl group which may be the same as R ^101, and is preferably a cyclic group containing a fluorine atom, a chain alkyl group, or a chain alkenyl group. Among them, a fluorinated alkyl group is preferable, and a group similar to the fluorinated alkyl group for Rd ¹ is more preferable.

In formula (d1-3), Rd ⁴ may have a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a substituent. It is a chain alkenyl group, and examples thereof include those similar to R ¹⁰¹ .
Among them, an alkyl group which may have a substituent, an alkoxy group, an alkenyl group and a cyclic group are preferable.
The alkyl group for Rd ⁴ is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group. , Tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like. Part of the hydrogen atoms of the alkyl group of Rd ⁴ may be substituted with a hydroxyl group, a cyano group or the like.
The alkoxy group for Rd ⁴ is preferably an alkoxy group having 1 to 5 carbon atoms, and specific examples of the alkoxy group having 1 to 5 carbon atoms include methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n- Examples thereof include butoxy group and tert-butoxy group. Of these, a methoxy group and an ethoxy group are preferable.

Examples of the alkenyl group for Rd ⁴ include those similar to the above R ^101, and a vinyl group, a propenyl group (allyl group), a 1-methylpropenyl group, and a 2-methylpropenyl group are preferable. These groups may further have, as a substituent, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms.

Examples of the cyclic group for Rd ⁴ include the same groups as those for R ¹⁰¹ described above, and one or more hydrogen atoms are excluded from cycloalkane such as cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane and tetracyclododecane. Also preferred are alicyclic groups or aromatic groups such as phenyl and naphthyl groups. When Rd ⁴ is an alicyclic group, the resist composition is well dissolved in an organic solvent, and thus the lithographic properties are good. When Rd ⁴ is an aromatic group, the resist composition is excellent in light absorption efficiency in lithography using EUV or the like as an exposure light source, and sensitivity and lithographic characteristics are good.

In formula (d1-3), Yd ¹ is a single bond or a divalent linking group.
The divalent linking group for Yd ¹ is not particularly limited, but a divalent hydrocarbon group (aliphatic hydrocarbon group, aromatic hydrocarbon group) optionally having a substituent, or a hetero atom-containing 2 Examples thereof include a valent linking group. Examples of each of these are the same as those mentioned in the description of the divalent linking group for Ya ²¹ in the formula (a2-1).
Yd ¹ is preferably a carbonyl group, an ester bond, an amide bond, an alkylene group or a combination thereof. The alkylene group is more preferably a linear or branched alkylene group, further preferably a methylene group or an ethylene group.

Specific preferred examples of the anion moiety of the component (d1-3) are shown below.

-Cation part In formula (d1-3), Mm ⁺ is an m-valent organic cation and is the same as Mm ⁺ in the formula (d1-1).
As the component (d1-3), one type may be used alone, or two or more types may be used in combination.

As the component (D1), only one type of the above-mentioned components (d1-1) to (d1-3) may be used, or two or more types may be used in combination.
The content of the component (D1) is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, and 1 to 8 parts by mass with respect to 100 parts by mass of the component (A). More preferably, it is parts by mass.
When the content of the component (D1) is at least the preferred lower limit value, particularly good lithographic properties and resist pattern shapes will be obtained. On the other hand, when it is at most the upper limit value, the sensitivity can be maintained well and the throughput is also excellent.

The method for producing the above-mentioned component (d1-1) and component (d1-2) is not particularly limited and can be produced by a known method.

The content of the component (D1) is preferably 0.5 to 10.0 parts by mass, more preferably 0.5 to 8.0 parts by mass, relative to 100 parts by mass of the component (A). , 1.0 to 8.0 parts by mass is more preferable. When it is at least the lower limit value of the above range, particularly good lithographic properties and resist pattern shape can be obtained. When it is at most the upper limit of the above range, the sensitivity can be favorably maintained and the throughput is also excellent.

(D2) component:
The component (D) may contain a nitrogen-containing organic compound component (hereinafter referred to as the component (D2)) that does not correspond to the component (D1).
The component (D2) is not particularly limited as long as it acts as an acid diffusion controller and does not correspond to the component (D1), and any known component may be used. Of these, aliphatic amines, especially secondary aliphatic amines and tertiary aliphatic amines are preferred.
The aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic group preferably has 1 to 12 carbon atoms.
Examples of the aliphatic amine include amines (alkylamines or alkylalcoholamines) or cyclic amines in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or a hydroxyalkyl group having 12 or less carbon atoms.
Specific examples of the alkylamine and alkylalcoholamine include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine and n-decylamine; diethylamine, di-n-propylamine, di-amine. Dialkylamines such as -n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine , Tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, tri-n-dodecylamine and like trialkylamines; diethanolamine, triethanolamine, diisopropanolamine, tri Examples include alkyl alcohol amines such as isopropanol amine, di-n-octanol amine, and tri-n-octanol amine. Among these, a trialkylamine having 5 to 10 carbon atoms is more preferable, and tri-n-pentylamine or tri-n-octylamine is particularly preferable.

Examples of the cyclic amine include a heterocyclic compound containing a nitrogen atom as a hetero atom. The heterocyclic compound may be a monocyclic compound (aliphatic monocyclic amine) or a polycyclic compound (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
The aliphatic polycyclic amine preferably has 6 to 10 carbon atoms, and specifically, 1,5-diazabicyclo[4.3.0]-5-nonene and 1,8-diazabicyclo[5. 4.0]-7-undecene, hexamethylenetetramine, 1,4-diazabicyclo[2.2.2]octane and the like can be mentioned.

Other aliphatic amines include tris(2-methoxymethoxyethyl)amine, tris{2-(2-methoxyethoxy)ethyl}amine, tris{2-(2-methoxyethoxymethoxy)ethyl}amine, tris{2. -(1-methoxyethoxy)ethyl}amine, tris{2-(1-ethoxyethoxy)ethyl}amine, tris{2-(1-ethoxypropoxy)ethyl}amine, tris[2-{2-(2-hydroxy) Ethoxy)ethoxy}ethyl]amine, triethanolamine triacetate and the like can be mentioned, with triethanolamine triacetate being preferred.

An aromatic amine may be used as the component (D2).
Examples of aromatic amines include aniline, pyridine, 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or their derivatives, diphenylamine, triphenylamine, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxy. Carbonyl pyrrolidine etc. are mentioned.

The component (D2) may be used alone or in combination of two or more kinds.
The component (D2) is usually used in the range of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the component (A). By setting the amount within the above range, the resist pattern shape, the stability over time with leaving and the like are improved.

As the component (D), one type may be used alone, or two or more types may be used in combination.
In the present embodiment, when the resist composition contains the component (D), the amount of the component (D) is preferably 0.1 to 15 parts by mass, and 0.3 to 100 parts by mass of the component (A). It is more preferably ˜12 parts by mass, further preferably 0.5 to 12 parts by mass.
When it is at least the lower limit value of the above range, the lithographic properties such as LWR are further improved when the composition is used as a resist composition. Further, a better resist pattern shape can be obtained. When it is at most the upper limit of the above range, the sensitivity can be favorably maintained and the throughput is also excellent.

≪Arbitrary ingredients≫
(E) component:
In the present embodiment, the resist composition contains, as an optional component, an organic carboxylic acid, and an oxo acid of phosphorus and its derivative for the purpose of preventing sensitivity deterioration and improving resist pattern shape, leaving stability over time, and the like. At least one compound (E) selected from the group consisting of (E) (hereinafter referred to as component (E)) can be contained.
As the organic carboxylic acid, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Examples of phosphorus oxo acids include phosphoric acid, phosphonic acid, and phosphinic acid. Of these, phosphonic acid is particularly preferable.
Examples of the oxo acid derivative of phosphorus include esters in which the hydrogen atom of the above oxo acid is substituted with a hydrocarbon group, and the hydrocarbon group includes an alkyl group having 1 to 5 carbon atoms and 6 to 6 carbon atoms. The aryl group of 15 and the like can be mentioned.
Examples of phosphoric acid derivatives include phosphoric acid esters such as phosphoric acid di-n-butyl ester and phosphoric acid diphenyl ester.
Examples of the derivative of phosphonic acid include phosphonic acid dimethyl ester, phosphonic acid-di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, and phosphonic acid dibenzyl ester.
Examples of the phosphinic acid derivative include phosphinic acid ester and phenylphosphinic acid.
As the component (E), one type may be used alone, or two or more types may be used in combination.
The component (E) is usually used in the range of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the component (A).

(F) component:
In the present embodiment, the resist composition may contain a fluorine additive (hereinafter referred to as “component (F)”) in order to impart water repellency to the resist film.
Examples of the component (F) are disclosed in JP2010-002870A, JP2010-032994A, JP2010-277043A, JP2011-13569A, and JP2011-128226A. The fluorine-containing polymer compounds described can be used.
More specifically, the component (F) includes a polymer having a structural unit (f1) represented by the following formula (f1-1). As the polymer, a polymer (homopolymer) consisting only of the structural unit (f1) represented by the following formula (f1-1); the structural unit (f1) represented by the following formula (f1-1) and the above Copolymer with the structural unit (a1): a structural unit (f1) represented by the following formula (f1-1), a structural unit derived from acrylic acid or methacrylic acid, and the structural unit (a1) It is preferably a copolymer. Here, as the structural unit (a1) copolymerized with the structural unit (f1) represented by the following formula (f1-1), 1-ethyl-1-cyclooctyl (meth)acrylate or the above formula (a1) 2-01) is preferred.

［式中、Ｒは前記同様であり、Ｒｆ^１０２およびＲｆ^１０３はそれぞれ独立して水素原子、ハロゲン原子、炭素数１〜５のアルキル基、又は炭素数１〜５のハロゲン化アルキル基を表し、Ｒｆ^１０２およびＲｆ^１０３は同じであっても異なっていてもよい。ｎｆ^１は１〜５の整数であり、Ｒｆ^１０１はフッ素原子を含む有機基である。］

[In the formula, R is the same as above, and Rf ¹⁰² and Rf ¹⁰³ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, Rf ¹⁰² and Rf ¹⁰³ may be the same or different. nf ¹ is an integer of ¹ to 5, and Rf ¹⁰¹ is an organic group containing a fluorine atom. ]

In formula (f1-1), R is the same as the above. R is preferably a hydrogen atom or a methyl group.
In formula (f1-1), examples of the halogen atom of Rf ¹⁰² and Rf ¹⁰³ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is particularly preferable. Examples of the alkyl group having 1 to 5 carbon atoms of Rf ¹⁰² and Rf ¹⁰³ are the same as those of the alkyl group having 1 to 5 carbon atoms of R above, and a methyl group or an ethyl group is preferable. Specific examples of the halogenated alkyl group having 1 to 5 carbon atoms of Rf ¹⁰² and Rf ¹⁰³ include a group in which a part or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms is substituted with a halogen atom. Can be mentioned. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is particularly preferable. Among them, Rf ¹⁰² and Rf ¹⁰³ are preferably a hydrogen atom, a fluorine atom or an alkyl group having 1 to 5 carbon atoms, and a hydrogen atom, a fluorine atom, a methyl group or an ethyl group is preferable.
In formula (f1-1), nf ¹ is an integer of ¹ to 5, preferably an integer of 1 to 3, and more preferably 1 or 2.

In formula (f1-1), Rf ¹⁰¹ is an organic group containing a fluorine atom, and is preferably a hydrocarbon group containing a fluorine atom.
The hydrocarbon group containing a fluorine atom may be linear, branched or cyclic, and has preferably 1 to 20 carbon atoms, and more preferably 1 to 15 carbon atoms. Particularly preferably, the carbon number is 1 to 10.
Further, in the hydrocarbon group containing a fluorine atom, 25% or more of the hydrogen atoms in the hydrocarbon group are preferably fluorinated, more preferably 50% or more, and more preferably 60% or more. Fluorination is particularly preferable because the hydrophobicity of the resist film at the time of immersion exposure increases.
Among them, as Rf ¹⁰¹ , a fluorinated hydrocarbon group having 1 to 5 carbon atoms is particularly preferable, and a methyl group, —CH ₂ —CF ₃ , —CH ₂ —CF ₂ —CF ₃ , or —CH(CF ₃ ) _{2 is used. , -CH} 2 _-CH 2 _-CF 3, and most preferably _{-CH 2 -CH 2 -CF 2 -CF 2} -CF 2 -CF 3.

The weight average molecular weight (Mw) of the component (F) (polystyrene conversion standard by gel permeation chromatography) is preferably from 1000 to 50,000, more preferably from 5,000 to 40,000, and most preferably from 10,000 to 30,000. When it is at most the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and when it is at least the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
The dispersity (Mw/Mn) of the component (F) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5.

As the component (F), one type may be used alone, or two or more types may be used in combination.
The component (F) is usually used in a proportion of 0.5 to 10 parts by mass with respect to 100 parts by mass of the component (A).

In the present embodiment, the resist composition further includes a miscible additive if desired, for example, an additional resin for improving the performance of the resist film, a dissolution inhibitor, a plasticizer, a stabilizer, a colorant, an antihalation agent. Agents, dyes, and the like can be appropriately added and contained.

(S) component:
In the present embodiment, the resist composition can be manufactured by dissolving the material in an organic solvent (hereinafter sometimes referred to as the component (S)).
As the component (S), any component capable of dissolving each component to be used to form a uniform solution may be used, and any one of the conventionally known solvents for a chemically amplified resist may be used, or Two or more kinds can be appropriately selected and used.
For example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone (MEK), cyclohexanone, methyl-n-pentyl ketone (2-heptanone), and methyl isopentyl ketone; ethylene glycol, diethylene glycol, propylene glycol, diketone. A polyhydric alcohol such as propylene glycol; a compound having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, or dipropylene glycol monoacetate, a polyhydric alcohol or a compound having an ester bond Derivatives of polyhydric alcohols such as compounds having an ether bond such as monoalkyl ethers such as monomethyl ether, monoethyl ether, monopropyl ether and monobutyl ether, and compounds having an ether bond such as monophenyl ether [among these, propylene glycol monomethyl ether acetate (PGMEA ), and propylene glycol monomethyl ether (PGME) are preferred]; cyclic ethers such as dioxane, methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methoxy. Esters such as methyl propionate and ethyl ethoxypropionate; anisole, ethylbenzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, Examples thereof include aromatic organic solvents such as cymene and mesitylene, dimethyl sulfoxide (DMSO), and the like.
These organic solvents may be used alone or as a mixed solvent of two or more kinds.
Of these, PGMEA, PGME, γ-butyrolactone and EL are preferable.
A mixed solvent obtained by mixing PGMEA and a polar solvent is also preferable. The compounding ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, but is preferably 1:9 to 9:1, more preferably 2:8 to 8:2. It is preferably within the range.
More specifically, when EL or cyclohexanone is blended as the polar solvent, the mass ratio of PGMEA:EL or cyclohexanone is preferably 1:9 to 9:1, more preferably 2:8 to 8:2. .. When PGME is blended as the polar solvent, the mass ratio of PGMEA:PGME is preferably 1:9 to 9:1, more preferably 2:8 to 8:2, and further preferably 3:7 to 7:. It is 3.
Further, as the component (S), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, as the mixing ratio, the mass ratio of the former and the latter is preferably 70:30 to 95:5.
The amount of the component (S) used is not particularly limited and is appropriately set according to the coating film thickness at a concentration that can be applied to a substrate or the like. Generally, the resist composition is used so that the solid content concentration is in the range of 1 to 20% by mass, preferably 2 to 15% by mass.

(Polymer composition for thickening pattern)
The pattern thickening polymer composition of the second aspect of the present invention is a pattern thickening polymer composition used for thickening a resist prepattern, wherein the resist prepattern is thickened. It contains a block copolymer containing a functional block chain (b1).
The pattern thickening polymer composition of the present embodiment is the same as the pattern thickening polymer composition used in the above-described resist pattern forming method.

Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to the following examples.
Note that Examples 11, 12 and 13 are reference examples.

<Preparation of resist composition>
The components shown in Table 1 were mixed and dissolved to prepare a chemically amplified resist composition.

Each abbreviation in Table 1 has the following meaning. Moreover, the numerical value in [] is a compounding quantity (mass part).
(A)-1: A polymer compound represented by the following chemical formula (A)-1. The standard polystyrene equivalent weight average molecular weight (Mw) determined by GPC measurement was 9000, and the molecular weight dispersity (Mw/Mn) was 1.56. ^The copolymerization composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by ¹³ C-NMR was 1/m/n/o/p=30/20/20/10/20.

(B)-1: An acid generator comprising a compound represented by the following chemical formula (B)-1.
(D)-1: An acid diffusion controller comprising a compound represented by the following chemical formula (D)-1.
(F)-1: A fluorine-containing polymer compound represented by the following chemical formula (F)-1. The weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement is 23100, and the molecular weight dispersity (Mw/Mn) is 1.78. ^The copolymerization composition ratio (the ratio (molar ratio) of each structural unit in the structural formula) determined by ¹³ C-NMR was 1/m=77/23.
(S)-1: γ-butyrolactone.
(S)-2: mixed solvent of propylene glycol monomethyl ether acetate/propylene glycol monomethyl ether/cyclohexanone=45/30/25 (mass ratio).

<Preparation of pattern thickening polymer composition>
Each of the copolymers (P)-1 to (P)-19 shown in Table 2 was obtained by synthesizing by a known polymerization method.
The copolymers (P)-1 to (P)-6 are random copolymers having no order in the arrangement of the monomers M1 and M2.
In the copolymers (P)-7 to (P)-19, the partial structural component (block chain (b2)) in which the structural unit derived from the monomer M1 is repeatedly bonded and the structural unit derived from the monomer M2 are repeated. It is a block copolymer in which the bonded partial constituents (block chain (b1)) are bonded.
Table 2 shows the standard polystyrene-equivalent weight average molecular weight (Mw) and molecular weight dispersity (Mw/Mn) of the obtained copolymer by GPC measurement.

M1 and M2 representing monomers in Table 2 mean monomers having the following chemical structures, respectively.

100 parts by mass of each of the copolymers (P)-1 to (P)-19 obtained above was dissolved in 6500 parts by mass of butyl acetate to obtain a polymer composition for pattern thickening.

<Formation of resist pattern>
(Comparative Examples 1-6, Examples 1-16)
A resist pattern having a thickened resist pre-pattern was formed by the following series of steps A, B, C and D.

[Process A]
A 12-inch silicon wafer was coated with an organic antireflection film composition "ARC-29A" (trade name, manufactured by Brewer Science Co., Ltd.) using a spinner and baked on a hot plate at 205°C for 60 seconds. By drying, an organic antireflection film having a film thickness of 89 nm was formed to prepare a support.
Next, the above chemically amplified resist composition was applied onto the organic antireflection film using a spinner, and prebaked (PAB) was performed on a hot plate at a temperature of 105° C. for 60 seconds. By drying, a resist film having a film thickness of 85 nm was formed.
Then, an ArF excimer laser (193 nm) was applied to the resist film with an exposure apparatus NSRX609B (manufactured by Nikon Corporation; NA1.07, Annual) for each mask pattern (6% halftone) of the following targets (1) to (3). Illuminated selectively via.
Target (1): Dense CH 110nm pitch/60nm CH
Target (2): Iso CH 300nm pitch/60nm CH
Target (3): Oval-X 55 nm/Oval-Y 138 nm, Y-CD/X-CD=2.5.
Then, a post exposure bake (PEB) process was performed under the conditions of a temperature of 80° C. and a time of 60 seconds.
Then, solvent development was performed for 13 seconds using butyl acetate.
As a result, a hole pattern was formed as a resist prepattern.

[Step B]
On the support on which the resist pre-pattern is formed, so as to cover the resist pre-pattern, the pattern thickening polymer composition obtained above, each is applied using a spinner, to form a polymer film. Formed. The coating film thickness of this polymer film was set to 60 nm.

[Step C]
After the [Step B], the resist pre-pattern and the polymer film covering the resist pre-pattern were heated at the heating temperature shown in Tables 3 and 4 for 60 seconds.

[Process D]
After the above [Step C], solvent development was performed for 13 seconds using butyl acetate.
As a result, a fine hole pattern having a thickened resist pre-pattern and a reduced hole diameter was formed.

<Evaluation of width of thickened portion (shrink volume: SV)>
For each hole pattern formed above, the width (shrink volume (nm)) of the thickened portion corresponding to “T _0a +T _0b (=T ₀ )” in FIG. 1D is calculated by the following method. evaluated.
Each resist pre-pattern and each hole pattern after step D were observed from above the pattern by a length-measuring SEM (scanning electron microscope, accelerating voltage 500V, trade name: CG5000, manufactured by Hitachi High-Technologies Corporation), and the target. The hole diameter was measured in the patterns (1) and (2), and the hole short axis and the hole long axis were measured in the target (3) pattern.

Regarding the shrink volume in the pattern of the target (1), the difference in hole diameter between the resist pre-pattern and the hole pattern after the step D is described as "Dense CH" in Tables 3 and 4 below.
Regarding the shrink volume in the pattern of the target (2), the difference in hole diameter between the resist pre-pattern and the hole pattern after the step D is shown as "Iso CH" in Tables 3 and 4 below.
Regarding the shrink volume in the pattern of the target (3), the difference between the resist pre-pattern and the hole pattern after the step D is defined as "Oval-X", and the difference between the hole major axes is "Oval-Y". And Table 4.
Further, (Oval-Y)/(Oval-X) was obtained as the amount of change in the aspect ratio of the (elliptical) hole before and after thickening the resist pre-pattern. The results are shown in Tables 3 and 4 below as "Y/X". The closer "Y/X" is to 1, the smaller the variation in the aspect ratio of the hole cross section due to the thickening of the resist prepattern.

As can be seen from the results shown in Tables 3 and 4, according to the resist pattern forming methods of Examples 1 to 16 to which the present invention was applied, the shrink volume was larger than that of Comparative Examples 1 to 6, so that the hole diameter It can be confirmed that a smaller hole pattern is formed.
That is, it is understood that a finer pattern can be formed by a simple method by the resist pattern forming method of the present invention.

From the comparison between Example 7 and Comparative Example 5 (the heating temperature is the same), by using the block copolymer, the effect of thickening the resist pre-pattern can be enhanced even with a low molecular weight polymer. I can confirm.

1... Support,
2... Resist pre-pattern,
3... Polymer film,
3a... developer insoluble layer,
4... Resist pattern

Claims (9)

A method of forming a resist pattern having a thickened resist pre-pattern,
An operation of forming a resist prepattern on a support using a resist composition containing a resin component whose solubility in an organic solvent is reduced by the action of an acid , and developing the resist film with an organic solvent to form a resist prepattern And a step A including
A step B of forming a polymer film by coating a pattern thickening polymer composition on a support on which the resist prepattern is formed so as to cover the resist prepattern,
Step C of forming a developer insoluble layer on the surface of the resist prepattern,
A step D of developing the resist pre-pattern having the developer-insoluble layer formed on the surface and the polymer film covering the resist pre-pattern to form a resist pattern in which the resist pre-pattern is thickened;
Have
The pattern thickening polymer composition contains a block copolymer containing a block chain (b1) having a thickening function of the resist pre-pattern and a block chain (b2) having a styrene skeleton,
The block chain (b1) has a basic group,
In the step C, the block chain (b1) having the basic group and the resist prepattern are neutralized to form a developer insoluble layer on the surface of the resist prepattern,
The molar ratio of the block chain (b1) to the block chain (b2) is such that the structural unit constituting the block chain (b1)/the structural unit constituting the block chain (b2)=1/99 to 10/90 A method for forming a resist pattern, which is less than 1. The resist pattern forming method according to claim 1, wherein the block copolymer includes the block chain (b1) at an end of a main chain. Structural units that constitute the block chain (b1) is a structural unit represented by the following general formula (b1-u1), a resist pattern forming method according to claim 1 or 2.

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Vx ⁰¹ is a divalent hydrocarbon group having an ester bond or an amide bond, a divalent aromatic hydrocarbon group, or a single bond. Yx ⁰¹ is a single bond or a divalent linking group. Rx ¹ is an organic group having a nitrogen atom . ] The block copolymer of the degree of dispersion (weight average molecular weight / number average molecular weight) is 1.5 or less, a resist pattern forming method according to any one of claims 1-3. The resist pre pattern is a hole pattern, the resist pattern forming method according to any one of claims 1-4. An operation of forming a resist pre-pattern on a support using a resist composition containing a resin component whose solubility in an organic solvent is reduced by the action of an acid, and developing the resist film with an organic solvent to form a resist pre-pattern And a step A including
A step B of forming a polymer film by coating a pattern thickening polymer composition on a support on which the resist prepattern is formed so as to cover the resist prepattern,
Step C of forming a developer insoluble layer on the surface of the resist prepattern,
A step D of developing the resist pre-pattern having the developer-insoluble layer formed on the surface and the polymer film covering the resist pre-pattern to form a resist pattern in which the resist pre-pattern is thickened;
A pattern thickening polymer composition used in a method for forming a resist pattern , comprising:
A block copolymer containing a block chain (b1) having a function of thickening the resist pre-pattern and a block chain (b2) having a styrene skeleton,
The block chain (b1) has a basic group,
In the step C, the block chain (b1) having the basic group and the resist prepattern are neutralized to form a developer insoluble layer on the surface of the resist prepattern,
The molar ratio of the block chain (b1) to the block chain (b2) is such that the structural unit of the block chain (b1)/the structural unit of the block chain (b2)=1/99 to 10/90. A polymer composition for pattern thickening, characterized by being less than. The pattern thickening polymer composition according to claim 6 , wherein the block copolymer contains the block chain (b1) at an end of a main chain. The polymer composition for pattern thickening according to claim 7 , wherein the structural unit constituting the block chain (b1) is a structural unit represented by the following general formula (b1-u1).

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Vx ⁰¹ is a divalent hydrocarbon group having an ester bond or an amide bond, a divalent aromatic hydrocarbon group, or a single bond. Yx ⁰¹ is a single bond or a divalent linking group. Rx ¹ is an organic group having a nitrogen atom . ] The block copolymer of the degree of dispersion (weight average molecular weight / number average molecular weight) is 1.5 or less, pattern thickening polymer composition according to any one of claims 6-8.

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