JP6757623B2 - Polymer composition for thickening resist pattern and method for forming resist pattern - Google Patents

Description

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

In lithography technology, 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 and electron beams 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 developing treatment.
A resist material whose exposed portion changes to a characteristic that dissolves in a developing solution is called a positive type, and a resist material whose exposed portion changes to a characteristic that does not dissolve in a developing solution is called a negative type.

In the manufacture of semiconductor elements and liquid crystal display elements, pattern miniaturization is progressing due to advances in lithography technology.
As a method for miniaturizing a pattern, generally, the wavelength of an exposure light source is shortened (energy is increased). Specifically, in the past, ultraviolet rays typified by g-rays and i-rays were used, but nowadays, mass production of semiconductor devices using KrF excimer lasers and ArF excimer lasers is being carried out. Further, studies are being conducted on electron beams having a shorter wavelength (higher energy) than these excimer lasers, EUV (extreme ultraviolet), X-rays, and the like.

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

A positive-type chemically amplified resist composition, that is, a positive-type developing process in which a chemically amplified resist composition whose solubility in an alkaline developer is increased by exposure and an alkaline developer is combined is a negative-type chemically amplified resist composition. Compared with the negative development process in which the resist composition and the alkaline developer are combined, there are advantages such as a simple structure of the photomask and excellent characteristics of the formed pattern. For this reason, at present, a positive development process in which a positive chemically amplified resist composition and an alkaline developer are combined is mainly used for forming a fine pattern.

When the positive development process is applied, when the chemically amplified resist composition is applied onto the support and selectively exposed to the resist film obtained, the exposed portion of the resist film undergoes acid decomposition in the base resin. The sexual group decomposes due to the action of the acid generated from the acid generator, etc., and changes from sparingly soluble to soluble in the alkaline developer, while the unexposed part of the resist film remains sparingly soluble in alkali, so it is alkaline. By developing with a developing solution, a dissolution contrast can be provided between the exposed portion and the unexposed portion, 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 weak optical intensity is generated in the exposed portion of the resist film, especially in the film thickness direction. , The resolution of the resist pattern tends to decrease.

For the formation of a fine pattern as described above, a method in which a region having a weak optical intensity is selectively dissolved and removed to form a resist pattern (negative resist pattern) is useful. As a method of forming a negative resist pattern using a chemically amplified resist composition used in the mainstream positive development process, a negative development process combined with a developer containing an organic solvent (organic developer) Is known (see, for example, Patent Document 1).
When the negative developer is applied, when the chemically amplified resist composition is applied onto the support and selectively exposed to the resist film obtained, the exposed portion of the resist film undergoes acid decomposition in the base resin. The sexual group decomposes due to the action of the acid generated from the acid generator, etc., and changes from soluble to sparingly soluble in the organic developer, while the unexposed part of the resist film remains soluble and does not change. 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.

Japanese Unexamined Patent Publication No. 2013-178515

In recent years, the pattern has been rapidly miniaturized due to further progress in lithography technology and expansion of application fields. Among them, when manufacturing a semiconductor element or the like, a technique capable of forming a fine pattern having a size of less than 100 nm in a good shape is required.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resist pattern forming method capable of forming a finer pattern in a good shape, and a polymer composition for thickening the resist pattern used therefor. To do.

A first aspect of the present invention is a polymer composition for thickening a resist pattern used for thickening a resist prepattern whose surface is exposed to acidic groups, and has a thickening function of the resist prepattern. The resin component (X) contains a resin component (X) and a base component (Y), and the resin component (X) has a structural unit derived from a monomer (mx) containing a basic group. The base component (Y) has a pKa in which the acid dissociation constant (pKa) of its conjugate acid is smaller than the pKa of the conjugate acid of the monomer (mx), and has a log P value of 7.5 or less. A polymer composition for thickening a resist pattern, which comprises the compound (Y1).

A second aspect of the present invention is a method of forming a resist pattern in which the resist pre-pattern is thickened, the step A of forming a resist pre-pattern in which acidic groups are exposed on the surface on the support, and the above-mentioned step A. A step B of applying the resist pattern thickening polymer composition according to the first aspect onto a support on which the resist pre-pattern is formed so as to cover the resist pre-pattern to form a polymer film. Step C of forming a developing solution insoluble layer on the surface of the resist prepattern, and developing the resist prepattern on which the developing solution insoluble layer is formed on the surface and the polymer film covering the resist prepattern are developed. This is a resist pattern forming method, which comprises a step D of forming a thickened resist pattern.

According to the present invention, it is possible to provide a resist pattern forming method capable of forming a finer pattern in a good shape, and a polymer composition for thickening the resist pattern used therefor.

It is a schematic process diagram explaining one Embodiment of the resist pattern formation method.

In the present specification and claims, "aliphatic" is defined as a concept relative to aromatics and means groups, compounds, etc. that do not have aromaticity.
Unless otherwise specified, the "alkyl group" shall include linear, branched chain and cyclic monovalent saturated hydrocarbon groups.
Unless otherwise specified, the "alkylene group" shall include linear, branched and cyclic divalent saturated hydrocarbon groups. The same applies to the alkyl group in the alkoxy group.
The "alkyl halide group" is a group in which a part or all of the hydrogen atom of the alkyl group is substituted with a halogen atom, and examples of the halogen atom include 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 a part or all of hydrogen atoms of the alkyl group or the alkylene group is substituted with a fluorine atom.
The "constituent unit" means a monomer unit (monomer unit) constituting a polymer compound (resin, polymer, copolymer).
The “constituent unit derived from the acrylic acid ester” means a structural unit formed by cleaving the ethylenic double bond of the acrylic acid ester.
The "acrylic acid ester" is a compound in which the hydrogen atom at the terminal of the carboxy group of acrylic acid (CH ₂ = CH-COOH) is replaced with an organic group.
In the acrylic acid ester, the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. The substituent (R ^α ) that replaces the hydrogen atom bonded to the carbon atom at the α-position is an atom or group other than the hydrogen atom, for example, an alkyl group having 1 to 5 carbon atoms and a halogenation having 1 to 5 carbon atoms. Examples thereof include an alkyl group and a hydroxyalkyl group. The carbon atom at the α-position of the acrylic acid 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. Further, the acrylic acid ester and the α-substituted acrylic acid ester may be collectively referred to as “(α-substituted) acrylic acid ester”.
"Constituent unit derived from hydroxystyrene or hydroxystyrene derivative" means a structural unit formed by cleaving the ethylenic double bond of hydroxystyrene or hydroxystyrene derivative.
The "hydroxystyrene derivative" is a concept including a hydrogen atom at the α-position of hydroxystyrene substituted with another substituent such as an alkyl group or an alkyl halide group, and derivatives thereof. As those derivatives, the hydrogen atom at the α-position may be substituted with a substituent, the hydrogen atom of the hydroxyl group of hydroxystyrene is substituted with an organic group, or the hydrogen atom at the α-position is substituted with a substituent. Examples thereof include a good hydroxystyrene benzene ring to which a substituent other than a hydroxyl group is bonded. The α-position (carbon atom at the α-position) refers to a carbon atom to which a benzene ring is bonded unless otherwise specified.
Examples of the substituent substituting the hydrogen atom at the α-position of hydroxystyrene include the same as those mentioned as the substituent at the α-position in the α-substituted acrylic acid ester.
The "constituent unit derived from vinyl benzoic acid or vinyl benzoic acid derivative" means a structural unit formed by cleaving the ethylenic double bond of vinyl benzoic acid or vinyl benzoic acid derivative.
The "vinyl benzoic acid derivative" is a concept including those in which the hydrogen atom at the α-position of vinyl benzoic acid is substituted with another substituent such as an alkyl group or an alkyl halide group, and derivatives thereof. As those derivatives, the hydrogen atom at the α-position may be substituted with a substituent, the hydrogen atom of the carboxy group of vinyl benzoic acid is substituted with an organic group, and the hydrogen atom at the α-position is substituted with a substituent. Examples thereof include a vinyl benzoic acid having a benzene ring bonded to a substituent other than a hydroxyl group and a carboxy group. The α-position (carbon atom at the α-position) refers to a carbon atom to which a benzene ring is bonded unless otherwise specified.
The "styrene derivative" means that the hydrogen atom at the α-position of styrene is substituted with another substituent such as an alkyl group or an alkyl halide group.
“Constituent unit derived from styrene” and “constituent unit derived from styrene derivative” mean a structural unit formed by cleavage of an ethylenic double bond of styrene or a styrene derivative.
The alkyl group as the substituent at the α-position is preferably a linear or branched alkyl group, and 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.
Further, the alkyl halide group as the substituent at the α-position is specifically a group in which a part or all of the hydrogen atom of the above-mentioned "alkyl group as the substituent at the α-position" is substituted with a halogen atom. Be done. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is particularly preferable.
Specific examples of the hydroxyalkyl group as the substituent at the α-position include a group in which a part or all of the hydrogen atom of the above-mentioned "alkyl group as the substituent at the α-position" is substituted with a hydroxyl group. The number of hydroxyl groups in the hydroxyalkyl group is preferably 1 to 5, and most preferably 1.
When it is described that "it may have a substituent", when the hydrogen atom (-H) is replaced with a monovalent group and when the methylene group (-CH _2- ) is replaced with a divalent group. Including both.
"Exposure" is a concept that includes general irradiation of radiation.

(Polymer composition for thickening resist pattern)
The polymer composition for thickening the resist pattern of the present embodiment (hereinafter, also simply referred to as “polymer composition”) is used for thickening the resist pre-pattern in which acidic groups are exposed on the surface. It contains a resin component (X) having a thickening function of the resist pre-pattern and a base component (Y).
Such a polymer composition is suitably used, for example, in a resist pattern forming method having steps A, B, C and D described later.

In the present invention, "thickening the resist pre-pattern" means changing the size of the previously formed pattern (shrink), and by thickening the pattern, for example, if it is a hole pattern, an opening is formed. The hole portion is narrowed (the hole diameter is reduced); if the line and space pattern is used, the line width is widened and the space width is narrowed.

<Resin component (X)>
The resin component (X) (hereinafter, also referred to as “component (X)”) has a thickening function of a resist pre-pattern in which acidic groups are exposed on the surface.
In the present invention, "having a thickening function of the resist pre-pattern" means that it interacts with the resist pre-pattern to newly form a part of the pattern (developer insoluble layer) on the surface of the resist pre-pattern. Means to have.
In the present embodiment, the component (X) has a structural unit derived from a monomer (mx) containing a basic group (hereinafter, this is referred to as "constituent unit (b1)").

Structural unit (b1):
The structural unit (b1) is a structural unit derived from a monomer (mx) containing a basic group, that is, a structural unit containing a basic group that neutralizes with an acidic group exposed on the surface of the resist prepattern. is there.
Since the component (X) has a structural unit (b1) containing a basic group, the basic group and the acidic group exposed on the surface of the resist prepattern interact with each other in step C. Therefore, a developer-insoluble layer is easily formed on the surface of the resist pre-pattern.
The basic group in the structural unit (b1) is appropriately selected in consideration of the type of resist prepattern formed in step A.

A preferable monomer (mx) is a compound having an acid dissociation constant (pKa) of the conjugate acid of more than 6, more preferably a compound having a pKa of the conjugate acid of 7 to 12, and a compound having a pKa of the conjugate acid of 7. Compounds 5 to 11 are more preferred.
When the pKa of the conjugate acid is within the above-mentioned preferable range, the action with the acidic group exposed on the surface of the resist pre-pattern is enhanced, and the developer insoluble layer is easily formed.

In the present invention, the "acid dissociation constant (pKa)" is generally used as an index indicating the acid strength of the target substance.
The pKa of the conjugate acid of the monomer (mx) can be measured and determined by a conventional method. Further, calculated values using known software such as "ACD / Labs" (trade name, manufactured by Advanced Chemistry Development) can also be used.

The basic groups in the structural unit (b1), preferably "organic group having a nitrogen atom" exemplified in the description of Rx ¹ of the general formula (b1-U1-1) in which will be described later.

As a preferable structural unit (b1), for example, a structural unit represented by the following general formula (b1-u1-1) can be mentioned.

［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、塩基性基を含む有機基である。］

[In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or an alkyl halide group having 1 to 5 carbon atoms. 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 divalent linking group. Rx ¹ is an organic group containing a basic group. ]

[R]
In the above formula (b1-u1-1), R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkyl halide 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, a methyl group, an ethyl group, a propyl group, an isopropyl group, or 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 alkyl halide group having 1 to 5 carbon atoms in R is a group in which a part 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, an iodine atom and the like, 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 above formula (b1-u1-1), 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 is preferably a single bond.

The hydrocarbon group of Vx ⁰¹ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Aliphatic hydrocarbon groups mean hydrocarbon groups that do not have aromaticity.
Examples of Vx ⁰¹ include those in which the divalent hydrocarbon group has an ether bond or an amide bond.

-Alphatic Hydrocarbon Group The aliphatic hydrocarbon group in Vx ⁰¹ may be saturated or unsaturated, and is usually preferably saturated.
More specific 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.

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 preferably 1 to 4 carbon atoms. More preferably, 1 to 3 are most preferable.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable, and specifically, a methylene group [−CH ₂ −], an ethylene group [− (CH ₂ ) ₂ −], and a trimethylene group [ − (CH ₂ ) ₃ −], tetramethylene group [− (CH ₂ ) ₄ −], pentamethylene group [− (CH ₂ ) ₅ −] and the like can be mentioned.
The branched-chain aliphatic hydrocarbon group preferably has 3 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, still more preferably 3 or 4, and most preferably 3.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferable, and specifically, -CH (CH ₃ )-, -CH (CH ₂ CH ₃ )-, -C (CH ₃ ). Alkylmethyl groups such as _2- , -C (CH ₃ ) (CH ₂ CH ₃ )-, -C (CH ₃ ) (CH ₂ CH ₂ CH ₃ )-, -C (CH ₂ CH ₃ ) _2-, etc.;- 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 -etc. Alkylethylene groups; -CH (CH ₃ ) CH ₂ CH _2- , -CH ₂ CH (CH ₃ ) CH ₂ -etc. Alkylmethyl group; -CH (CH ₃ ) Examples thereof include alkylalkylene groups such as alkyltetramethylene groups such as CH ₂ CH ₂ CH ₂ − and −CH ₂ CH (CH ₃ ) CH ₂ CH ₂ −. As the alkyl group in the alkylalkylene group, a linear alkyl group having 1 to 5 carbon atoms is preferable.

An aliphatic hydrocarbon group containing a ring in the structure The aliphatic hydrocarbon group containing a ring in the structure is 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 Examples include groups intervening in. Examples of the linear or branched aliphatic hydrocarbon group include the same groups 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 a polycyclic type or a monocyclic type. As the monocyclic alicyclic hydrocarbon group, a group obtained by removing two hydrogen atoms from a monocycloalkane is preferable. 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 a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, specifically. Examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

-Aromatic hydrocarbon group An aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring.
The aromatic 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 most preferably 6 to 10 carbon atoms. However, the carbon number does not include the carbon number in the substituent.
Specifically, the aromatic ring contained in the aromatic hydrocarbon group is an aromatic hydrocarbon ring such as benzene, biphenyl, fluorene, naphthalene, anthracene, or phenanthrene; a part of carbon atoms constituting the aromatic hydrocarbon ring is heterogeneous. Aromatic heterocycles substituted with atoms; etc. Examples of the hetero atom in the aromatic heterocycle include an oxygen atom, a sulfur atom, a nitrogen atom and the like.
Specifically, as the aromatic hydrocarbon group, a group obtained by removing two hydrogen atoms from the aromatic hydrocarbon ring (arylene group, preferably a phenylene group or a naphthylene group); a hydrogen atom from the aromatic hydrocarbon ring. A group in which one of the hydrogen atoms of the removed group (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 the formula (b1-u1-1), Yx ⁰¹ is a single bond or a divalent linking group.
The divalent linking group in Yx ⁰¹ is not particularly limited, but a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a heteroatom, and the like are preferable.

-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.
Aliphatic hydrocarbon groups mean hydrocarbon groups that do not have 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.

The linear aliphatic hydrocarbon group in Yx ⁰¹ , the branched aliphatic hydrocarbon group, and the aliphatic hydrocarbon group containing a ring in the structure include the linear aliphatic hydrocarbon group in Vx ⁰¹ . , Aliphatic hydrocarbon groups in the form of branched chains, 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, a carbonyl group and the like.

The aliphatic hydrocarbon group containing the ring may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, an alkyl halide group, a hydroxyl group, a carbonyl group and the like.
As the alkyl group as the substituent, an alkyl group having 1 to 5 carbon atoms is preferable, and a methyl group, an ethyl group, a propyl group, an n-butyl group and a tert-butyl group are most preferable.
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 methoxy. Groups and ethoxy groups are most preferred.
Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.
Examples of the alkyl halide group as the substituent include a group in which a part or all of the hydrogen atom of the alkyl group is substituted with the halogen atom.
In the aliphatic hydrocarbon group containing a ring, a part of carbon atoms constituting the ring structure may be substituted with a substituent containing a hetero atom. The substituent containing a hetero atom, -O -, - C (= O) -O -, - S -, - S (= O) 2 -, - S (= O) 2 -O- are preferred.

Examples of the aromatic hydrocarbon group in Yx ⁰¹ include those similar to the aromatic hydrocarbon group in Vx ⁰¹ .
In the aromatic hydrocarbon group, the hydrogen atom contained in 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, an alkyl halide group, a hydroxyl group and the like.
As the alkyl group as the substituent, an alkyl group having 1 to 5 carbon atoms is preferable, and a methyl group, an ethyl group, a propyl group, an n-butyl group and a tert-butyl group are most preferable.
Examples of the alkoxy group, halogen atom and alkyl halide 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, for example, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom and the like. Can be mentioned.

When Yx ⁰¹ is a divalent linking group containing a hetero atom, preferred linking groups are -O-, -C (= O) -O-, -C (= O)-, -OC (. = O) -O-, -C (= O) -NH-, -NH-, -NH-C (= NH)-(H may be substituted with a substituent such as an alkyl group or 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 ^- group represented by wherein, Y ²¹ and Y ²² are each independently a divalent which may have a substituent hydrocarbon group, O is an oxygen atom, m ' Is an integer from 0 to 3. ] Etc. can be mentioned.
When the divalent linking group containing a hetero atom is -C (= O) -NH-, -NH-, -NH-C (= NH)-, the H is a substituent such as an alkyl group or an acyl group. It may be replaced. 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 the same as 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 alkyl methylene 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 Or 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, further 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, as Yx ⁰¹ , a divalent linking group is preferable, a divalent linking group containing a hetero atom is more preferable, and an ester bond [-C (= O) -O-] and an ether bond (-O-) are preferable. , A linear or branched alkylene group, or a combination thereof is particularly preferable.

[Rx ¹ ]
In the above formula (b1-u1-1), Rx ¹ is an organic group containing a basic group.
The organic group containing a basic group is not particularly limited as long as it can interact with the acidic group exposed on the surface of the resist prepattern to form a developer-insoluble layer on the surface of the resist prepattern.
As the organic group containing a basic group, for example, an organic group having a nitrogen atom is preferable.

As the organic group having a nitrogen atom, for example, primary aliphatic amines, secondary aliphatic amines, tertiary aliphatic amines, aromatic amines or heterocyclic amines are suitable. Listed as a thing.

Examples of 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, diddecylamine, N, N-dimethylethylenediamine, N, N-dimethyltetra Ethylenepentamine, 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 Isopropanolamine, 2-aminoethanol, 3-amino-1-propanol, 4-amino-1-butanol, 2,2,6,6, tetramethylpiperidin, 2,2,6,6, pentamethylpiperidine and the like. Be done.

Examples of aromatic amines or heterocyclic amines include aniline, diphenyl (p-tolyl) amine, methyldiphenylamine, triphenylamine, phenylenediamine, naphthylamine, diaminonaphthalene, pyrrol, oxazole, thiazole, imidazole, pyrazole, frazan, and pyrolin. , Pyrrolidine, imidazoline, imidazolidine, pyridine (preferably 2- (2-hydroxyethyl) pyridine), pyridazine, pyrimidine, pyrazine, pyrazoline, pyrazolidine, piperazine, piperazine (preferably 1- (2-hydroxyethyl) piperazine, 1, -[2- (2-Hydroxyethoxy) ethyl] piperazine, morpholine (preferably 4- (2-hydroxyethyl) morpholine), indole, isoindole, 1H-indazole, indolin, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline, Examples thereof include phthalazine, purine, pteridine, carbazole, phenanthrazine, aclysine, phenazine, 1,10-phenanthroline, adenine, adenosine, guanine, guanosine, uracil and uridine.
These aromatic amines or heterocyclic amines may have a substituent. Preferred substituents include 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, a lactone group and the like.

Among them, Rx ¹ is preferably a group represented by either the following general formula (Rx-1) or (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_０は０〜８の整数であり、＊はＹｘ^０１との結合手を示す。］

[In the formula, Rx ^{01 to} Rx ⁰⁴ are each independently a hydrogen atom or a linear or branched-chain alkyl group, n ₀ is an integer of ₀ to 8, and * is Yx ⁰¹ . Show the bond. ]

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, or 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 ₀ is an integer from ₀ to 8, preferably 2 or 4.

Specific examples of the groups represented by the general 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), the group represented by the following general formula (Rx-2-1) is preferable. Among the groups represented by the following general formula (Rx-2-1), the group represented by the 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 * Indicates a bond with Yx ⁰¹ . ]

The linear or branched alkyl groups of Rx ^{05 to} Rx ⁰⁶ and Rx ^{061 to} Rx ⁰⁶⁴ are the same as those described in Rx ^{01 to} Rx ⁰⁴ . n1 is an integer from 0 to 8.

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

As the structural unit (b1), a structural unit represented by any of the following general formulas (b1-u1-11) to (b1-u1-13) 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。Ｒ^ｓｔは、水素原子又はメチル基である。Ｙｘ^０１’は、単結合又は２価の炭化水素基である。Ｒｘ^１は、塩基性基を含む有機基を示す。］

[In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or an alkyl halide group having 1 to 5 carbon atoms. R ^st is a hydrogen atom or a methyl group. Yx ⁰¹ 'is a single bond or a divalent hydrocarbon group. Rx ¹ represents an organic group containing a basic group. ]

In the formulas (b1-u1-11) to (b1-u1-13), the description of R, Yx ⁰¹ and Rx ¹ is the same as described above. The divalent hydrocarbon group for Yx ⁰¹ 'is similar to the description of the divalent hydrocarbon group for ^{Yx 01.}

Specific examples of the structural unit (b1) will be described below. In the following specific examples, R and R ^st are the same as described above.

The pKa of the conjugate acid of the monomer (mx) that induces the structural unit (b1) given as the above specific example is shown below.
PKa10.13 of the monomeric conjugate acid that induces the structural unit (b1-1) (R = CH ₃ )
PKa9.41 of the monomeric conjugate acid that induces the structural unit (b1-2) (R = CH ₃ )
PKa10.76 of the monomeric conjugate acid that induces the structural unit (b1-3) (R = CH ₃ )
PKa10.53 of the monomeric conjugate acid that induces the structural unit (b1-4) (R = CH ₃ )
PKa8.18 of the monomeric conjugate acid that induces the structural unit (b1-11) (R = CH ₃ )
PKa9.18 of the monomeric conjugate acid that induces the structural unit (b1-12) (R = CH ₃ )
PKa9.33 of the monomeric conjugate acid that induces the structural unit (b1-13) (R = CH ₃ )
PKa8.34 of the monomeric conjugate acid that induces the building block (b1-14) (R = CH ₃ )
PKa8.02 of the monomeric conjugate acid that induces the structural unit (b1-15) (R = CH ₃ )
PKa9.74 of the monomeric conjugate acid that induces the building block (b1-16) (R = CH ₃ )
PKa10.55 of the monomeric conjugate acid that induces the structural unit (b1-17) (R = CH ₃ )
PKa 14.51 of the monomeric conjugate acid that induces the structural unit (b1-23) (R = CH ₃ )
PKa14.18 of the monomeric conjugate acid that induces the building block (b1-24) (R = CH ₃ )
PKa14.88 of the monomeric conjugate acid that induces the building block (b1-25) (R = CH ₃ )
PKa14.76 of the monomeric conjugate acid that induces the building block (b1-26) (R = CH ₃ )

The structural unit (b1) contained in the component (X) may be one type or two or more types.
The ratio of the structural unit (b1) in the component (X) is preferably 50 mol% or less, more preferably 1 to 50 mol%, or 2) with respect to all the structural units (100 mol%) constituting the component (X). ~ 25 mol% is more preferred.
When the ratio of the structural unit (b1) is at least the lower limit of the above-mentioned preferable range, the thickening effect of the resist pre-pattern can be more easily obtained. On the other hand, when it is not more than the upper limit value of the above-mentioned preferable range, it becomes easy to balance with other structural units.

Other building blocks:
The component (X) may further have other structural units in addition to the structural unit (b1).
Examples of other structural units include a structural unit having a styrene skeleton, a structural unit (a4) described later, a structural unit (a9) represented by the following general formula (a9-1), and the like.

.. A structural unit having a styrene skeleton (hereinafter referred to as "constituent unit (st)")
The component (X) preferably has a structural unit (st) in addition to the structural unit (b1). By having the structural unit (st), the resist pre-pattern can be thickened more efficiently.

Examples of the structural unit (st) include hydroxystyrene, a hydroxystyrene derivative, or a structural unit derived from styrene.
The number of hydroxyl groups bonded to the benzene ring of hydroxystyrene is preferably 1, 2 or 3, and more preferably 1.
Preferred structural units (st) include the structural unit (st1) represented by the following general formula (I) or the 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 formula (I), R ^st represents a hydrogen atom or a methyl group, and m ₀₁ represents an integer of 1 to 3. In 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 an integer of 0 or 1 to 3. ]

In the formula (I), R ^st is a hydrogen atom or a methyl group, and is preferably a hydrogen atom.
m ₀₁ is an integer of 1 to 3, and is preferably 1.
The substitution position of the hydroxyl group may be any of the o-position, the m-position, and the p-position. Since it is easily available and inexpensive, it is preferable that m ₀₁ is 1 and that it has a hydroxyl group at the p-position. When m ₀₁ is 2 or 3, any substitution position can be combined.

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

The above m ₀₂ is an integer of 0 or 1-3. Of these, m ₀₂ is preferably 0 or 1, and is particularly preferably industrially 0.
When m ₀₂ is 1, the replacement position of R ⁰¹ may be any of the o-position, m-position, and p-position, and when m ₀₂ is 2 or 3, it is arbitrary. Replacement positions can be combined.

The structural unit (st) contained in the component (X) may be one type or two or more types.
When the component (X) has a structural unit (st), the ratio of the structural unit (st) in the component (X) is 99 mol% with respect to all the structural units (100 mol%) constituting the component (X). The following is preferable, 50 to 99 mol% is more preferable, and 75 to 98 mol% is particularly preferable.

・ ・ Structural unit (a9)
The structural unit (a9) is a structural unit represented by the following general formula (a9-1).

［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。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 a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or an alkyl halide group having 1 to 5 carbon atoms. 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 linking group. ]

In the formula (a9-1), R is the same as described above.
In the formula (a9-1), the divalent linking group in Ya ⁹¹ may be the same as the divalent linking group in Yx ⁰¹ in the formula (b1-u1-1). Ya ⁹¹ is preferably a single bond.

In the formula (a9-1), the divalent linking group in Ya ⁹² is the divalent linking group in Yx ⁰¹ in the formula (b1-u1-1), similarly to the divalent linking group in Ya ⁹¹ . (A divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, etc.) and the same can be mentioned.
In the divalent linking group in Ya ⁹² in the above formula (a9-1), the divalent hydrocarbon group which may have a substituent is a linear or branched aliphatic hydrocarbon group. Is preferable.
Further, in the divalent linking group in Ya ⁹² in the formula (a9-1), the divalent linking group which may have a hetero atom is -C (= O)-, -C (= S). )-Preferably.

In the formula (a9-1), examples of the hydrocarbon group in R ⁹¹ include an alkyl group, a monovalent alicyclic hydrocarbon group, an aryl group, and an aralkyl group.
The alkyl group in R ⁹¹ preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, further preferably 1 to 4 carbon atoms, and may be linear or branched. Specifically, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group and the like are preferable.
The monovalent alicyclic hydrocarbon group in R ⁹¹ preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms, and may be a polycyclic type or a monocyclic type. As the monocyclic alicyclic hydrocarbon group, a group obtained by removing one or more hydrogen atoms from a monocycloalkane is preferable. 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 a polycycloalkane, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, specifically. Examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
The aryl group in R ⁹¹ preferably has 6 to 18 carbon atoms, more preferably 6 to 10 carbon atoms, and specifically preferably a phenyl group.
The arylyl group in R ⁹¹ is preferably an aralkyl group having 7 to 10 carbon atoms, and the aralkyl group having 7 to 10 carbon atoms includes a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group and a 1-naphthyl group. Arylalkyl groups such as an ethyl group and a 2-naphthylethyl group can be mentioned.

The hydrocarbon group in R ⁹¹ may have a substituent. Examples of the substituent include a halogen atom, an oxo group (= O), a hydroxyl group (-OH), an amino group (-NH ₂ ), -SO _2- NH _{2 and the} like.
The hydrocarbon group in R ⁹¹ preferably has a part or all of the hydrogen atom of the hydrocarbon group substituted with a fluorine atom, and 30 to 100% of the hydrogen atom of the hydrocarbon group is substituted with a fluorine atom. Is more preferable. Among them, it is particularly preferable that all the hydrogen atoms of the above-mentioned alkyl group are perfluoroalkyl groups substituted with fluorine atoms.

Further, a part of the carbon atoms constituting the hydrocarbon group in R ⁹¹ may be substituted with a substituent containing a hetero atom. Substituents containing the heteroatom include -O-, -NH-, -N =, -C (= O) -O-, -S-, -S (= O) _2-, -S (= O). ) _2- O- can be mentioned.
In R ⁹¹ , examples of the hydrocarbon group having a substituent include lactone-containing cyclic groups represented by the general formulas (a2-r-1) to (a2-r-7) described later.
^Further, in ^{R 91,} examples of the hydrocarbon group having a substituent, -SO ₂ respectively represented by the general formula below (a5-r-1) ~ (a5-r-4) - containing cyclic group; following Examples thereof include a substituted aryl group represented by a chemical formula and a monovalent heterocyclic group.
In the following formula, "*" indicates a bond with Ya ⁹² .

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

［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 the same as above, Ya ⁹¹ is a single bond or 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 above formula (a9-1-1), the description of Ya ⁹¹ , R ⁹¹ , and R is the same as described above. Further, R ⁹² is an oxygen atom or a sulfur atom.

A specific example of the structural unit (a9) is shown below. In the following formula, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

The structural unit (a9) contained in the component (X) may be one type or two or more types.
When the component (X) has a structural unit (a9), the ratio of the structural unit (a9) in the component (X) is 1 mol% with respect to all the structural units (100 mol%) constituting the component (X). The above is preferable, 5 to 50 mol% is more preferable, and 10 to 40 mol% is further preferable.

In the present embodiment, the component (X) has a structural unit (b1), and for example, a polymer compound having a structural unit (b1) and a structural unit (st) (hereinafter, this is referred to as “(X1) component”. ".) Can be mentioned.
Among them, as the component (X1), a polymer compound having a repeating structure of a structural unit (b1) and a structural unit (st2) is preferably mentioned.

In the (X1) component,
The ratio of the structural unit (b1) is preferably 1 mol% or more, more preferably 1 to 50 mol%, and further 1 to 10 mol% with respect to all the structural units (100 mol%) constituting the component (X1). preferable.
The ratio of the structural unit (st2) is preferably 99 mol% or less, more preferably 50 to 99 mol%, and further 90 to 99 mol% with respect to all the structural units (100 mol%) constituting the component (X1). preferable.

The weight average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography) of the component (X1) is not particularly limited, but is preferably 1000 to 200,000, more preferably 1000 to 100,000, and further preferably 1000. ~ 50,000. The higher the Mw of the component (X1), the larger the width (shrink volume: S.V.) of the thickened portion can be adjusted, and the thicker effect can be easily obtained.
The degree of dispersion (weight average molecular weight / number average molecular weight) of the component (X1) is preferably 1.50 or less, more preferably 1.40 or less, and particularly preferably 1.30 or less.

As the component (X1), it is preferable to use a component obtained by living polymerization because it can be narrowly dispersed and the effect of thickening the resist pre-pattern is further enhanced. Preferred living anionic polymerization methods include living anionic polymerization and living radical polymerization, and living anionic polymerization is preferable because the effect of thickening the resist prepattern is further enhanced.

In the polymer composition for thickening the resist pattern, the component (X1) may be used alone or in combination of two or more.
The ratio of the component (X1) to the component (X) is preferably 50% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and may be 100% by mass, and 100% by mass is used. Especially preferable.

≪ (X2) component ≫
The component (X) contained in the polymer composition for thickening the resist pattern is a polymer compound other than the above-mentioned component (X1) from the viewpoint of controlling the pattern shape before and after the thickening of the resist pre-pattern (hereinafter, "" (X2) component ") may be used in combination.

The component (X2) is not particularly limited, and for example, a component having no thickening function of the resist pre-pattern (a polymer that cannot form a developer-insoluble layer on the surface of the resist pre-pattern in step D described later) is used. Can be mentioned.
The component (X2) is selected from the group consisting of the constituent unit (a1), the constituent unit (a2), the constituent unit (a3), and the constituent unit (a5) represented by the following general formula (a5-1), which will be described later. Those having at least one kind of.

［式中、Ｒは前記と同様であり、Ｒａ^５１は炭素数１〜５の直鎖状若しくは分岐鎖状のアルキル基、又は炭素数１〜５の直鎖状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 alkyl fluorinated chain having 1 to 5 carbon atoms. Is the basis. ]

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

The component (X2) may be a copolymer or a homopolymer.
As the component (X2), a monomer for inducing each structural unit can be obtained, for example, by known radical polymerization using a radical polymerization initiator.

The weight average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography) of the component (X2) is not particularly limited, and is preferably 1000 to 1000000, more preferably 1500 to 500000, and most preferably 2000 to 300,000. preferable. By setting the weight average molecular weight of the component (X2) in the above range, the pattern can be satisfactorily thickened.

In the polymer composition for thickening the resist pattern, the component (X2) may be used alone or in combination of two or more.

<Base component (Y)>
In the present embodiment, the base component (Y) (hereinafter, also referred to as “(Y) component”) is a monomer (mx) in which the acid dissociation constant (pKa) of the conjugate acid induces the structural unit (b1). ) Contains a compound (Y1) having a pKa smaller than the acid dissociation constant (pKa) of the conjugate acid and having a logP value of 7.5 or less (hereinafter, also referred to as “(Y1) component”).

The component (Y1) is not particularly limited as long as it is a compound in which the acid dissociation constant (pKa) of the conjugate acid is smaller than the pKa of the conjugate acid of the above-mentioned monomer (mx), and for example, the monomer (mx). It is selected in consideration of the type of.
As the component (Y1), a compound having a pKa of the conjugate acid of 2 to 10 is preferable, a compound having a pKa of the conjugate acid of 2 to 9 is more preferable, and a compound having a pKa of the conjugate acid of 2.5 to 7 is further preferable. Preferably, a compound having a pKa of the conjugate acid of 3 to 5 is particularly preferable, and a compound having a pKa of the conjugate acid of 3 to 4 is most preferable.
When the pKa of the conjugate acid of the component (Y1) is within the above-mentioned preferable range, the shrink volume (SV) is further increased, and the resist pattern shape is further improved. When the pKa of the conjugate acid of the component (Y1) is equal to or less than the upper limit of the above-mentioned preferable range, S.I. V. Is easy to be raised.

In addition, as the component (Y1), a compound having a logP value of 7.5 or less is preferable, a compound having a logP value of 7.0 or less is more preferable, and a compound having a logP value of 6.0 or less is further preferable. A compound having a logP value of -1 to 5.0 is particularly preferable, and a compound having a logP value of -1 to 4.0 is most preferable.
When the logP value of the component (Y1) is within the above-mentioned preferable range, the shrink volume (SV) is further increased, and the resist pattern shape is further improved.

The "logP value" here means a logarithmic value of the octanol / water partition coefficient ( _Power ). The "logP value" is an effective parameter capable of characterizing the hydrophilicity / hydrophobicity of a wide range of compounds. In general, the partition coefficient can be obtained by calculation regardless of the experiment, and in the present invention, CS ChemDraw Ultra Ver. The value calculated by 8.0 software package (Crippen's fragmentation method) is shown.
When the logP value increases on the positive side across 0, the hydrophobicity increases, and when the absolute value increases on the negative side, the water solubility increases (high polarity). The logP value has a negative correlation with the water solubility of the organic compound, and is widely used as a parameter for estimating the affinity hydrophobicity of the organic compound.

The component (Y1) is preferably a compound having a molecular weight of less than 1000, more preferably a compound having a molecular weight of 500 or less, further preferably a compound having a molecular weight of 50 to 300, and having a molecular weight of 50 from the viewpoint of solubility in a developing solution. ~ 250 compounds are particularly preferred.
When the molecular weight of the component (Y1) is less than the upper limit of the above-mentioned preferable range, the occurrence of defects such as precipitation during development is likely to be suppressed.

Preferred examples of the (Y1) component include compounds represented by any of the following general formulas (Y1-1) to (Y1-3).

［式（Ｙ１−１）中、Ｒ^ｙ１は、炭素数１〜５のアルキル基を表す。ｎ_ｙ１は０〜２の整数である。式（Ｙ１−２）中、Ｒ^ｙ２は、置換基を有してもよいフェニル基、置換基を有してもよいピリジル基、置換基を有してもよいクマリニル基又は炭素数１〜５のアルキル基を表す。Ｒ^ｙ３及びＲ^ｙ４は、それぞれ独立に、炭素数１〜５のアルキル基又は水素原子を表す。式（Ｙ１−３）中、Ｒ^ｙ５及びＲ^ｙ６は、それぞれ独立に、炭素数１〜１２のアルキル基を表す。］

[In the formula (Y1-1), R ^y1 represents an alkyl group having 1 to 5 carbon atoms. n _y1 is an integer from 0 to 2. In the formula (Y1-2), R ^y2 is a phenyl group which may have a substituent, a pyridyl group which may have a substituent, a cumlinyl group which may have a substituent, or 1 to 5 carbon atoms. Represents the alkyl group of. R ^y3 and R ^y4 each independently represent an alkyl group or a hydrogen atom having 1 to 5 carbon atoms. In the formula (Y1-3), R ^y5 and R ^y6 each independently represent an alkyl group having 1 to 12 carbon atoms. ]

In the formula (Y1-1), R ^y1 represents an alkyl group having 1 to 5 carbon atoms. Examples of ^Ry1 include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group and neopentyl group.
n _y1 is an integer of 0 to 2, preferably 0 or 1, and more preferably 0.

Examples of the compound represented by the general formula (Y1-1) include pyridazine (conjugate acid pKa3.12, logP = -0.51, molecular weight 80.1), 3-aminopyridazine, 3-methylpyridazine, and 3-methoxy. Examples include pyridazine.

In the above formula (Y1-2), R ^y2 is a phenyl group which may have a substituent, a pyridyl group which may have a substituent, a cumlinyl group which may have a substituent, or 1 to 1 carbon atoms. Represents an alkyl group of 5.
Examples of the alkyl group in R ^y2 include a methyl group, an ethyl group, 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.
Examples of the substituent that the phenyl group, pyridyl group or cumlinyl group in R ^y2 may have include an alkyl group having 1 to 5 carbon atoms, an amino group, a hydroxy group, a sulfo group and a methoxy group.

R ^y3 and R ^y4 each independently represent an alkyl group or a hydrogen atom having 1 to 5 carbon atoms.
Examples of the alkyl group in R ^y3 and R ^y4 include a methyl group, an ethyl group, 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.

Examples of the compound represented by the general formula (Y1-2) include 7-diethylamino-4-methylcoumarin (conjugate acid pKa 3.40, logP = 3.45, molecular weight 232.3), 2,6-diisopropylaniline ( Conjugate acid pKa4.25, logP = 3.05, molecular weight 177.3), 4-dimethylaminopyridine (conjugate acid pKa9.20, logP = 1.34, molecular weight 122.2), trimethylamine (conjugate acid pKa9) .75, logP = 0.12, molecular weight 59.1) and the like.

In the above formula (Y1-3), R ^y5 and R ^y6 each independently represent an alkyl group having 1 to 12 carbon atoms.
The number of carbon atoms of the alkyl group in R ^y5 and R ^y6 is preferably 1 to 10, more preferably 1 to 8, and even more preferably 1 to 6.
R ^y5 and R ^y6 are not particularly limited in their bonding positions, but are preferably bonded to, for example, the 2-position and the 6-position of the pyridine ring, respectively.
Examples of the compound represented by the general formula (Y1-3) include 2,6-lutidine (conjugate acid pKa6.70, logP = 1.60, molecular weight 107.2) and 2,6-dihexylpyridine (conjugated acid). Examples thereof include pKa 6.67, logP = 6.70, and molecular weight 247.4).

Among the above, as the component (Y1), since the shrink volume (SV) is likely to be increased, the compound represented by any of the above general formulas (Y1-1) to (Y1-3) can be used. One or more selected from the group consisting of compounds represented by any of the general formulas (Y1-1) to (Y1-2) is more preferable, and one or more selected from the group consisting of compounds represented by any of the general formulas (Y1-1) to (Y1-2) is more preferable.

In the polymer composition for thickening the resist pattern, the component (Y1) may be used alone or in combination of two or more.
The content of the component (Y1) is preferably more than 0 parts by mass and 300 parts by mass or less, more preferably 1 to 300 parts by mass, and 50 to 200 parts by mass with respect to 100 parts by mass of the resin component (X). Is even more preferable.
When the polymer composition for thickening the resist pattern contains the component (Y1), the shrink volume (SV) is enhanced and the shape of the resist pattern is further improved. On the other hand, when the content of the component (Y1) is not more than the upper limit of the above-mentioned preferable range, the effect of improving the shrink volume (SV) is enhanced.

As the component (Y), a base component (component (Y2)) other than the above-mentioned component (Y1) may be used in combination.
The ratio of the component (Y1) to the component (Y) is preferably 50% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, and may be 100% by mass, and 100% by mass is used. Especially preferable.

In the polymer composition for thickening the resist pattern of the present embodiment, the ratio of the component (Y1) and the structural unit (b1) derived from the monomer (mx) is determined in consideration of each pKa and the like. For example, the component (Y1) is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, and the upper limit value is preferably 200 parts by mass or less with respect to 100 parts by mass of the constituent unit (b1).
When the mass ratio is within the above-mentioned preferable range, the shrink volume (SV) is increased and the resist pattern shape is further improved.

<Solvent>
The solvent contained in the polymer composition for thickening the resist pattern may be water or an organic solvent, and is not particularly limited as long as it does not dissolve the resist prepattern, and the resist pattern thickness to be used is not particularly limited. It can be appropriately selected depending on the material of the polymer composition for meat formation or the resist composition. It is preferable to use an organic solvent as such a solvent.
When water is used as the solvent, pure water is preferable.
When an organic solvent is used as the solvent, it is preferable to use one kind alone or two or more kinds of mixed solvents such as a ketone solvent, an ester solvent, an alcohol solvent, an amide solvent, and an ether solvent.
Among these, from the viewpoint of not dissolving the resist prepattern, it is more preferable to use an ester solvent, and it is particularly preferable to use butyl acetate.
Further, a mixed solvent in which butyl acetate and a polar solvent are mixed is also preferable. Examples of this polar solvent include ethyl lactate, cyclohexanone, propylene glycol monomethyl ether (PGME), and among these, PGME is preferable. When a mixed solvent of butyl acetate and PGME is used, the mass ratio of butyl acetate: PGME is preferably 70:30 to 99: 1, more preferably 80:20 to 95: 5, as the mixing ratio. ..
The total solid content concentration (total mass excluding the solvent) of the resist pattern thickening polymer composition is preferably 0.1 to 20 with respect to the total amount (100% by mass) of the resist pattern thickening polymer composition. It is by mass, more preferably 0.1 to 10% by mass, and even more preferably 0.1 to 5% by mass.

<Other ingredients>
The polymer composition for thickening the pattern of the present embodiment may contain other components other than the above-mentioned resin component and solvent, if necessary, as long as the effects of the present invention are not impaired.
Examples of other components include surfactants, plasticizers, photoreactive substances and the like.

(Resist pattern forming method)
The resist pattern forming method of the present embodiment is a method of forming a resist pattern in which the resist pre-pattern is thickened, and has the following steps A, B, C and D.
Step A: Forming a resist pre-pattern on the support with exposed acidic groups on the surface Step B: Resist pattern on the support on which the resist pre-pattern is formed so as to cover the resist pre-pattern. Step C: A step of forming a developer-insoluble layer on the surface of the resist pre-pattern Step D: A resist in which the developer-insoluble layer is formed on the surface of the resist pre-pattern by applying a thickening polymer composition. A step of developing the pre-pattern and the polymer film covering the pre-pattern to form a thick resist pattern of the resist pre-pattern.

Hereinafter, the resist pattern forming method of the present embodiment 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 the resist pattern forming method of the present embodiment, and shows a series of steps for thickening the hole pattern.
First, a resist pre-pattern 2 is formed on the support 1 using the resist composition (step A; FIG. 1 (a)). In the resist prepattern 2, the diameter of the hole there is a T _1. Acidic groups are exposed on the surface 2a of the resist prepattern 2.
Next, a polymer composition for thickening the resist pattern is applied onto the support 1 on which the resist pre-pattern 2 is formed so as to cover the resist pre-pattern 2, and the polymer in contact with the surface 2a of the resist pre-pattern 2 is applied. The film 3 is formed (step B; FIG. 1 (b)).
Next, a developer insoluble layer 3a (thickened portion) is formed on the resist pre-pattern 2 (step C; FIG. 1 (c)).
Next, the resist prepattern 2 on which the developer insoluble layer 3a is formed on the surface and the polymer film 3 covering the resist prepattern 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 holes, and a 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 pre-pattern 2 and the developer insoluble layer 3a. In the resist pattern 4, the resist pre-pattern 2 is thickened, and the hole diameter is reduced from T ₁ to T ₂ (T ₂ <T ₁ ). The width (shrink volume: S.V.) of the thickened portion in the radial direction of the hole is set to T ₀ (that is, T ₁ −T ₀ = T ₂ , T ₀ = T _0a + T _0b ).

[Step A]
Step A is a step of forming the resist pre-pattern 2 on the support 1.
Examples of the method for forming the resist pre-pattern 2 include an operation of forming a resist film on the support 1 using a resist composition, an operation of exposing the resist film, and an operation of developing the exposed resist film. , A method having an operation of forming a resist pre-pattern 2 having a surface 2a on which an acidic group is exposed can be mentioned.
As the resist composition, for example, a resist composition containing a resin component whose solubility in an organic solvent is reduced by the action of an acid is used. Details of the resist composition will be described later.

The resist pre-pattern can be formed, for example, as follows.
First, a resist composition described below is applied onto the support with a spinner or the like, and a bake (post-apply bake (PAB)) treatment is performed, for example, under a temperature condition of 80 to 150 ° C. for 40 to 120 seconds, preferably 60 to 60 to. It is applied for 90 seconds to form a resist film.
Next, the resist film is exposed or masked through a mask (mask pattern) on which a predetermined pattern is formed by using an exposure device such as an ArF exposure device, an electron beam drawing device, or an EUV exposure device. After selective exposure such as drawing by direct irradiation of an electron beam without intervention, baking (post-exposure baking (PEB)) treatment is performed, for example, under a temperature condition of 80 to 150 ° C. for 40 to 120 seconds, preferably 60 to 60 to. Apply for 90 seconds.

Next, the resist film is developed.
In the case of the alkaline developing process, the developing process is performed using an alkaline developing solution, and in the case of the solvent developing process, a developing solution containing an organic solvent (organic developing solution) is used.
The developing process may be an alkali developing process or a solvent developing process, but is preferably a solvent developing process. That is, the step A preferably includes an operation of developing the 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 an acid. It is more preferable to include an operation of forming a resist film on the support using an object and an operation of developing the resist film with an organic solvent to form a resist pre-pattern. That is, the resist pre-pattern formed in the step A is preferably a solvent-developed negative type resist pre-pattern.

In the case of the alkaline development process, for example, by the development process, the exposed part of the resist film is dissolved in the alkaline developer and removed, the unexposed part of the resist film remains, and the acidic group is exposed on the surface of the resist prepattern. Is formed.
In the case of the solvent development process, for example, the unexposed part of the resist film is dissolved in an organic developer and removed by the development process, the exposed part of the resist film remains, and the acidic group is exposed on the surface of the resist pre. A pattern is formed.
Examples of the acidic groups exposed on the surface of the resist pre-pattern, for example, such as a carboxyl group, a sulfo group (-SO 3 _H) and the like.

After the development treatment, a rinsing treatment is preferably performed. In the case of the alkaline development process, the rinsing treatment is preferably a water rinse using pure water, and in the case of the solvent development process, it is preferable to use a rinse solution containing an organic solvent.
In the case of the solvent development process, after the development treatment or the rinsing treatment, a treatment for removing the developing solution or the rinsing solution adhering to the pattern with a supercritical fluid may be performed.
Drying is performed after the development treatment or the rinsing treatment. In some cases, after the development treatment, for example, a baking treatment (post-baking) at about 100 ° C. may be performed.
As described above, 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 resist pattern forming method of the present embodiment is a particularly useful method when the shape of the resist pre-pattern in step A is a hole pattern (particularly an elliptical shape).

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

Exposure is not particularly limited, ArF excimer laser, KrF excimer laser, _{F 2} excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-rays, and soft X-rays using Can be done.

The exposure method of the resist film may be a normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or an immersion exposure (Liquid Immersion Lithography).
In 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 larger than the refractive index of air, and exposure (immersion exposure) is performed in that state. This is an exposure method.
As the immersion medium, a solvent having a refractive index larger than that of air and smaller than that of the resist film to be exposed is preferable. The refractive index of such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger than the refractive index of air and smaller than the refractive index 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 fluorine-based compounds 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 main components. Examples thereof include liquids, which have a boiling point of 70 to 180 ° C., and more preferably 80 to 160 ° C. When the fluorine-based inert liquid has a boiling point in the above range, it is preferable that the medium used for immersion can be removed by a simple method after the end of exposure.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms is particularly preferable. Specific examples of the perfluoroalkyl compound include a perfluoroalkyl ether compound and a perfluoroalkylamine compound.
Further, specifically, the perfluoroalkyl ether compound may include perfluoro (2-butyl-tetrahydrofuran) (boiling point 102 ° C.), and the perfluoroalkylamine compound may include perfluorotributylamine (perfluorotributylamine). Boiling point 174 ° C.).
As the immersion medium, water is preferably used from the viewpoints of cost, safety, environmental problems, versatility and the like.

Examples of the alkaline developer used in the developing process in the alkaline developing process include an aqueous solution of 0.1 to 10 mass% tetramethylammonium hydroxide (TMAH).
The organic solvent contained in the organic developer used in the developing process in the solvent developing process may be any one that can dissolve the component (A) blended in the resist composition (component (A) before exposure). 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.
A known additive can be added to the organic developer, if necessary. Examples of the additive include a surfactant. The surfactant is not particularly limited, and for example, an ionic or nonionic fluorine-based and / or silicon-based surfactant can be used.
When a surfactant is blended, the blending amount is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and 0.01 to 0.% With respect to the total amount of the organic developer. 5% by mass is more preferable.

The developing process can be carried out by a known developing method. For example, a method of immersing the support in a developing solution for a certain period of time (dip method), a method of raising the developing solution on the surface of the support by surface tension and allowing it to stand still for a certain period of time. (Paddle method), spraying the developer on the surface of the support (spray method), applying the developer on the support rotating at a constant speed while scanning the developer dispensing nozzle. Examples include a method of continuing (dynamic dispense method).

The rinsing treatment (cleaning treatment) using the rinsing liquid can be carried out by a known rinsing method. Examples of the method include a method of continuously spraying the rinse liquid on the support rotating at a constant speed (rotary coating method), a method of immersing the support in the rinse liquid for a certain period of time (dip method), and a support surface. A method of spraying the rinse solution (spray method) and the like can be mentioned.

[Step B]
In step B, the polymer composition for thickening the resist pattern of the present embodiment described above is placed on the support 1 on which the resist pre-pattern 2 is formed so as to cover the resist pre-pattern 2 formed in the step A. Is a step of forming a polymer film 3 in contact with the surface 2a of the resist prepattern 2.
For the polymer film 3, for example, the polymer composition for thickening the resist pattern is applied onto the support 1 on which the resist pre-pattern 2 is formed so as to cover a part or the whole of the resist pre-pattern 2 and dried. It is formed by letting it.
As a method for applying the polymer composition for thickening the resist pattern, a conventionally known spin coating method, spray method, roller coating method, dipping method or the like can be used, and the spin coating method is preferable.

[Step C]
Step C is a step of forming the developer insoluble layer 3a on the resist pre-pattern 2.
The polymer film 3 formed on the resist pre-pattern 2 in step B contains a resin component ((X) component) having a thickening function of the resist pre-pattern and a base component ((Y) component). It has been. After the polymer film 3 is formed, the component (X) and the resist prepattern 2 interact with each other to form a developer insoluble layer 3a (thickened portion).

In step C, it is preferable to heat (shrink bake) the resist prepattern 2 and the polymer film 3 covering the resist prepattern 2. By such heating, the action of the basic group contained in the component (X) in the polymer film 3 and the acidic group exposed on the surface 2a of the resist prepattern 2 is further strengthened, and the action is further strengthened on the surface 2a of the resist prepattern 2. The developer insoluble layer 3a (thickened portion) is easily formed. 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 copolymer in the pattern thickening polymer composition, or the required width of the thickened portion (shrink volume: SV). , Can be set as appropriate.
The heating temperature is preferably 0 to 200 ° C, more preferably 50 to 170 ° C, still more preferably 80 to 160 ° C, particularly preferably 100 to 150 ° C, and most preferably more than 100 ° C and 150 ° C or less. If the heating temperature is above the preferred lower limit, S.I. V. Can be further enhanced. When it is not more than a preferable upper limit value, the resist pattern shape is easily maintained well.
The heating time is preferably 30 to 300 seconds, more preferably 50 to 120 seconds, and particularly preferably 50 to 80 seconds.

In step C, the component (X) has a basic group that can be neutralized with an acidic group exposed on the surface 2a of the resist pre-pattern 2, and is exposed to such basicness and the surface 2a of the resist pre-pattern 2. It is preferable that the acidic group and the acid group interact with each other to form a developer-insoluble layer 3a on the surface 2a.
In step C, preferably by heating, residual solvent and the like are removed, and neutralization on the surface of the resist pre-pattern proceeds more satisfactorily.

[Step D]
Step D is a step of developing the resist pre-pattern 2 on which the developer insoluble layer 3a is formed and the polymer film 3 covering the resist pre-pattern 2 to form a resist pattern 4 in which the resist pre-pattern 2 is thickened. ..
By the development in the step D, the polymer film 3 portions other than the developer insoluble layer 3a and the excess or unreacted polymer composition for thickening the pattern are removed.

The developing process may be carried out by an alkaline developing process or a solvent developing process. In the case of the alkaline development process, an alkaline developer is used, and in the case of the solvent development process, a developer containing an organic solvent (organic developer) is used. Above all, the development treatment is preferably carried out by a solvent development process from the viewpoint of removal efficiency of the polymer composition for thickening the pattern.

After the development treatment, a rinsing treatment is preferably performed. In the case of the alkaline development process, the rinsing treatment is preferably a water rinse using pure water, and in the case of the solvent development process, it is preferable to use a rinse solution containing an organic solvent.
In the case of the solvent development process, after the development treatment or the rinsing treatment, a treatment for removing the developing solution or the rinsing solution adhering to the pattern with a supercritical fluid may be performed.
Drying is performed after the development treatment or the rinsing treatment. Further, in some cases, a baking process (post-baking) may be performed after the development process.
In this way, a desired resist pattern obtained by thickening the resist pre-pattern can be obtained.

According to the resist pattern forming method of the present embodiment, as shown in FIG. 1 (d), the hole diameter T ₁ is reduced to the hole diameter T ₂ due to the thickening of the resist pre-pattern 2. 4 can be easily formed.

As described above, in the resist pattern forming method of the present embodiment, the polymer composition for thickening the resist pattern of the above-described embodiment, that is, the structural unit derived from the monomer (mx) containing a basic group. A compound having a resin component (X) having (b1), a pKa smaller than the acid dissociation constant (pKa) of the conjugate acid of the monomer (mx), and a logP value of 7.5 or less ( A polymer composition containing Y1) and is used.
The combination of the (X) component and the (Y1) component having a specific pKa relationship is adopted, and in addition, the (Y1) component has a predetermined logP value, so that the shrink volume (S.V. ) Is enhanced, and the resist pattern shape is further improved. For example, the effect that the ratio (Y direction / X direction) of the elliptical hole diameter between the minor axis direction (X direction) and the major axis direction (Y direction) is maintained or increased can be obtained.
The reason why such an effect is obtained is presumed as follows. For example, in FIG. 1, the surface 2a of the resist pre-pattern 2 is in a state where acidic groups such as carboxylic acid are exposed due to deprotection of the base material component contained in the resist composition in step A. When the polymer composition for thickening the resist pattern of the above-described embodiment is coated here, the polymer composition for thickening the resist pattern comes into contact with the resist pre-pattern 2 and is acidic exposed on the surface 2a of the resist pre-pattern 2. The group and the basic group of the compound (Y1) contained in the polymer composition are first neutralized and bonded. Next, salt exchange occurs between the (Y1) component and the (X) component having a specific pKa relationship, and the basic group of the (X) component and the acidic group exposed on the surface 2a interact with each other. It is presumed that the developer insoluble layer 3a, which is insoluble in the developer during development in the subsequent step D, is more likely to be formed.

In the above-described embodiment, the resist pre-pattern is a hole pattern, but the present invention is not limited to this, and for example, a line-and-space pattern (hereinafter referred to as “LS pattern”) may be used. When the resist pre-pattern is an LS pattern, according to the resist pattern forming method of the present embodiment, a fine pattern in which the space width is sufficiently reduced can be easily formed, and the LS pattern can be further miniaturized.

<Resist composition>
The resist composition that can be used in step A in the resist pattern forming method of the present embodiment is a resist composition that generates an acid by exposure and whose solubility in a developing solution changes by the action of the acid. preferable.
The resist composition preferably contains a base material component (A) (hereinafter, also referred to as "component (A)") whose solubility in a developing solution is changed by the action of an acid.
When a resist film is formed using such a resist composition and selective exposure is performed on the resist film, an acid is generated in the exposed portion, and the action of the acid makes the component (A) soluble in a developing solution. On the other hand, since the solubility of the component (A) in the developing solution does not change in the unexposed portion, a difference in solubility in the developing solution occurs between the exposed portion and the unexposed portion. Therefore, when the resist film is developed, if the resist composition is a positive type, the exposed portion is dissolved and removed to form a positive type resist pattern, and if the resist composition is a negative type, the unexposed portion is dissolved. It 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 for forming a negative resist pattern in which an unexposed portion is dissolved and removed. Is called a negative resist composition.
In the present embodiment, the resist composition may be a positive resist composition or a negative resist composition.
Further, in the present embodiment, the resist composition may be used for an alkaline developing process in which an alkaline developing solution is used for the developing process at the time of forming the resist pattern, and the developing solution (organic developing solution) containing an organic solvent in the developing process. ) May be used for a solvent developing process, but it is preferably for a solvent developing process.

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

≪ (A) component ≫
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.
Organic compounds used as base material components are roughly classified into non-polymers and polymers.
As the non-polymer, those having a molecular weight of 500 or more and less than 4000 are usually used. Hereinafter, the term "low molecular weight compound" refers to 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 1000 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, the polystyrene-equivalent weight average molecular weight by GPC (gel permeation chromatography) shall be 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) has a change in solubility in a developing solution due to the action of an acid.
Further, in the present embodiment, the component (A) may be one that generates an acid by exposure.

In the present embodiment, the component (A) is a polymer compound (A1) having a structural unit (hereinafter, also referred to as “constituent unit (a1)”) containing an acid-degradable group whose polarity is increased by the action of an acid. It is preferable that A1) component) is contained.
(A1) component, in addition to the structural unit (a1), the lactone-containing cyclic group, -SO 2 _- also referred to as structural unit containing an containing cyclic group or a carbonate-containing cyclic group (hereinafter "structural unit (a2)" ), A structural unit containing a polar group-containing aliphatic hydrocarbon group (hereinafter, also referred to as “constituent unit (a3)”) may be provided.

Structural unit (a1):
The structural unit (a1) is a structural unit containing an acid-degradable group whose polarity is increased by the action of an acid.
An "acid-degradable group" is a group having an acid-degradability in which at least a part of the bonds in the structure of the acid-degradable group can be cleaved by the action of an acid.
Examples of the acid-degradable group whose polarity is increased by the action of an acid include a group which is decomposed by the action of an acid to produce an acidic group. The acidic group generated here becomes an acidic group exposed on the surface of the resist prepattern formed in step A.
The acidic groups, for example carboxy groups, sulfo group _(-SO 3 H) and the like. Among these, a sulfo group or a polar group containing −OH in the structure (hereinafter, may be referred to as “OH-containing polar group”) is preferable, a sulfo group and a carboxy group are more preferable, and a carboxy group is particularly preferable.
More specific examples of the acid-degradable group include a group in which the acidic group is protected by an acid dissociative group (for example, a group in which a hydrogen atom of an OH-containing polar group is protected by an acid dissociative group).
Here, the "acid dissociative group" is
(I) A group having acid dissociation that allows the bond between the acid dissociative group and an atom adjacent to the acid dissociative group to be cleaved by the action of an acid, or a group having acid dissociation.
(Ii) A group capable of cleaving the bond between the acid dissociative group and an atom adjacent to the acid dissociative group by further decarboxylation after the partial bond is cleaved by the action of the acid. ,
Refers to both.
The acid dissociative group constituting the acid-degradable group needs to be a group having a lower polarity than the acidic group generated by the dissociation of the acid-dissociative group, whereby the acid-dissociative group is caused by the action of an acid. When is dissociated, an acidic group having a higher polarity than the acid dissociative group is generated and the polarity is increased. As a result, the polarity of the entire (A1) component increases. As the polarity increases, the solubility in the developer changes relatively, and when the developer is an organic developer, the solubility decreases.

The acid dissociative group is not particularly limited, and those previously proposed as an acid dissociative group of the base resin for a chemically amplified resist can be used.
As the acid dissociative group that protects the acidic group, for example, an acid dissociative group represented by the following general formula (a1-r-1) (hereinafter, may be referred to as an “acetal-type acid dissociative group” for convenience). Can be mentioned.

［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。］

Wherein, Ra ^'1, Ra' ² represents a hydrogen atom or an alkyl group, Ra ^'3 is a hydrocarbon group, Ra' ³ is, Ra ^'1, Ra' ² of bonded either to form a ring Good. ]

Wherein (a1-r-1), as the Ra ^'1, Ra' ² alkyl groups, in the description of the α-substituted acrylic acid esters, mentioned as α-position substituent which may be bonded to the carbon atoms of Similar to the alkyl group, a methyl group or an ethyl group is preferable, and a methyl group is most preferable.

The ra ^'3 hydrocarbon group is preferably an alkyl group having 1 to 20 carbon atoms, the alkyl group is more preferably 1 to 10 carbon atoms; preferably a linear or branched alkyl group, 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 Examples thereof include a 2,2-dimethylpropyl group and a 2,2, -dimethylbutyl group.

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

In the case of an aromatic hydrocarbon group, the aromatic ring contained is specifically an aromatic hydrocarbon ring such as benzene, biphenyl, fluorene, naphthalene, anthracene, or phenanthrene; the carbon atom constituting the aromatic hydrocarbon ring. An aromatic heterocycle partially substituted with a hetero atom; and the like. Examples of the hetero atom in the aromatic heterocycle include an oxygen atom, a sulfur atom, a nitrogen atom and the like.
Specifically, the aromatic hydrocarbon group is a group obtained by removing one hydrogen atom from the aromatic hydrocarbon ring (aryl group); a group in which one of the hydrogen atoms of the aryl group is substituted with an alkylene group (for example). , Arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group); and the like. 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.

Ra ^'3 is, ra' ^1, if ra ^'2 of bonded either to form a ring, a cyclic group, 4- to 7-membered ring is preferred, 4 to 6-membered ring is more preferable. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

Examples of the acid dissociative group that protects the acidic group include an acid dissociative group represented by the following general formula (a1-r-2) (represented by the following formula (a1-r-2)). Among the acid dissociative groups, those composed of alkyl groups are hereinafter sometimes referred to as "tertiary alkyl ester type acid dissociative 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。］

Wherein, Ra ^'4 ~Ra' ⁶ is a hydrocarbon group, Ra ^'5, Ra' ⁶ may be bonded to each other to form a ring. ]

Examples of the hydrocarbon group Ra ^'4 ~Ra' ⁶ include the same as the Ra ^'3. Ra ^'4 is preferably an alkyl group having 1 to 5 carbon atoms. Ra If ^'5, Ra' ⁶ are bonded to each other to form a ring, a group represented by the following general formula (a1-r2-1).
On the other hand, Ra ^'4 ~Ra' ⁶ are not bonded to each other, when an independent hydrocarbon groups include groups represented by the following general formula (a1-r2-2).

［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。］

Wherein, Ra ^'10 is an alkyl group having 1 to 10 carbon atoms, Ra' ¹¹ is' group to form an aliphatic cyclic group together with the carbon atom ^{to which 10} are bonded, Ra 'Ra ¹² to Ra' ¹⁴ each Independently shows a hydrocarbon group. ]

Wherein (a1-r2-1), Ra 'alkyl group of the alkyl group having 1 to 10 carbon atoms ^10, Ra in formula (a1-r-1)' a linear or branched alkyl group of ³ The groups listed as are preferred. Wherein (a1-r2-1), Ra 'aliphatic cyclic ^{group 11} is configured, Ra in formula (a1-r-1)' group listed as a cyclic alkyl group of ³ is preferred.

Wherein (a1-r2-2), it is preferable that Ra is ^'12 and Ra' ¹⁴ each independently represents an alkyl group having 1 to 10 carbon atoms, the alkyl group, Ra in formula (a1-r-1) The group listed as the linear or branched alkyl group of ' ³ is more preferable, the linear alkyl group having 1 to 5 carbon atoms is more preferable, and the methyl group or the ethyl group is particularly preferable. ..
Wherein (a1-r2-2) that, Ra ^'13 has the formula (a1-r-1) in the Ra' ³ of the illustrated linear hydrocarbon group, branched or cyclic alkyl group Is preferable. Among these, it is more preferably a group listed as a cyclic alkyl group of Ra ^'3.

Specific examples of the above formula (a1-r2-1) are given below. In the following formula, "*" indicates a bond.

Specific examples of the above formula (a1-r2-2) are given below.

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

Among the above, the structural unit (a1) is preferably a structural unit derived from an acrylic acid ester in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent.
As the structural unit (a1), a structural unit represented by the following general formula (a1-1) or (a1-2) 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）で表される酸解離性基である。］

[In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or an alkyl halide group having 1 to 5 carbon atoms. 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 dissociative group represented by (a1-r-2). Wa ¹ is a n _a2 + 1 valent hydrocarbon group, _{na 2} is 1 to 3, and Ra ² is an acid dissociative group represented by the above formula (a1-r-1). ]

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, and specifically, a methyl group, an ethyl group, or the like. Examples thereof include propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like. The alkyl halide group having 1 to 5 carbon atoms is a group in which a part or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, 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), Va ¹ is a divalent hydrocarbon group which may have an ether bond, a urethane bond, or an amide bond.
The hydrocarbon group of Va ¹ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Aliphatic hydrocarbon groups mean hydrocarbon groups that do not have aromaticity.

-Alphatic Hydrocarbon Group The aliphatic hydrocarbon group as the divalent hydrocarbon group in Va ¹ may be saturated or unsaturated, and is usually preferably saturated.
More specific 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 Va ¹ include those in which the 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 preferably 1 to 4 carbon atoms. More preferably, 1 to 3 are most preferable.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable, and specifically, a methylene group [−CH ₂ −], an ethylene group [− (CH ₂ ) ₂ −], and a trimethylene group [ − (CH ₂ ) ₃ −], tetramethylene group [− (CH ₂ ) ₄ −], pentamethylene group [− (CH ₂ ) ₅ −] and the like can be mentioned.
The branched-chain aliphatic hydrocarbon group preferably has 3 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, still more preferably 3 or 4, and most preferably 3.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferable, and specifically, -CH (CH ₃ )-, -CH (CH ₂ CH ₃ )-, -C (CH ₃ ). Alkylmethyl groups such as _2- , -C (CH ₃ ) (CH ₂ CH ₃ )-, -C (CH ₃ ) (CH ₂ CH ₂ CH ₃ )-, -C (CH ₂ CH ₃ ) _2-, etc.;- 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 -etc. Alkylethylene groups; -CH (CH ₃ ) CH ₂ CH _2- , -CH ₂ CH (CH ₃ ) CH ₂ -etc. Alkylmethyl group; -CH (CH ₃ ) Examples thereof include alkylalkylene groups such as alkyltetramethylene groups such as CH ₂ CH ₂ CH ₂ − and −CH ₂ CH (CH ₃ ) CH ₂ CH ₂ −. As the alkyl group in the alkylalkylene group, a linear alkyl group having 1 to 5 carbon atoms is preferable.

An aliphatic hydrocarbon group containing a ring in the structure The aliphatic hydrocarbon group containing a ring in the structure is 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 Examples include groups intervening in. Examples of the linear or branched aliphatic hydrocarbon group include the same groups 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 a polycyclic type or a monocyclic type. As the monocyclic alicyclic hydrocarbon group, a group obtained by removing two hydrogen atoms from a monocycloalkane is preferable. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. As the polycyclic alicyclic hydrocarbon group, a group obtained by removing two hydrogen atoms from polycycloalkane is preferable, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically, adamantane. , Norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.

-Aromatic hydrocarbon group An aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring.
The aromatic hydrocarbon group as the divalent hydrocarbon group in Va ¹ 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 to 6 carbon atoms. 10 is most preferable. However, the carbon number does not include the carbon number in the substituent.
Specifically, the aromatic ring contained in the aromatic hydrocarbon group is an aromatic hydrocarbon ring such as benzene, biphenyl, fluorene, naphthalene, anthracene, or phenanthrene; a part of carbon atoms constituting the aromatic hydrocarbon ring is heterogeneous. Aromatic heterocycles substituted with atoms; etc. Examples of the hetero atom in the aromatic heterocycle include an oxygen atom, a sulfur atom, a nitrogen atom and the like.
Specifically, as the aromatic hydrocarbon group, a group obtained by removing two hydrogen atoms from the aromatic hydrocarbon ring (arylene group, preferably a phenylene group or a naphthylene group); a hydrogen atom from the aromatic hydrocarbon ring. A group in which one of the hydrogen atoms of the removed group (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.

In the formula (a1-2), n _{a2 +1} monovalent hydrocarbon group for Wa ¹ may be an aliphatic hydrocarbon group may be an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity, and 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 a linear or branched aliphatic hydrocarbon group. Examples thereof include a group in which a ring-containing aliphatic hydrocarbon group is combined in the structure, and specific examples thereof include the same group as Va ¹ in the above formula (a1-1).
The _na2 + 1 valence is preferably 2 to 4 valence, more preferably 2 or 3 valence.

As the formula (a1-2), a structural unit represented by the following general formula (a1-2-01) is particularly preferable.

In the formula (a1-2-01), Ra ² is an acid dissociative group represented by the above formula (a1-r-1). 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 ratio of the structural unit (a1) in the component (A1) is preferably 20 to 80 mol%, more preferably 20 to 75 mol%, and 25 to 70 mol% with respect to all the structural units constituting the component (A1). Is even more preferable. By setting the ratio of the structural unit (a1) to the lower limit value or more, the lithography characteristics such as sensitivity, resolution, and LWR are also improved. Further, by setting the value to the upper limit or less, it is possible to balance with other structural units.

Structural unit (a2):
The structural unit (a2), a lactone-containing cyclic group, -SO 2 _- is a structural unit containing an containing cyclic group or a carbonate-containing cyclic group.
Lactone-containing cyclic group of the structural unit (a2), -SO 2 _- containing cyclic group or a carbonate-containing cyclic group, when used for forming a resist film (A1) component, the adhesion of the resist film and the substrate It is effective in enhancing the sex.
In the present embodiment, the component (A1) preferably has a structural unit (a2).
Incidentally, the structural unit (a1) is a lactone-containing cyclic group in its structure, -SO 2 _- when is intended to include containing cyclic group or a carbonate-containing cyclic group, in the structural units of the structural unit (a2) corresponding 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 the following general formula (a2-1).

［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 an alkyl halide 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-, where R'indicates a hydrogen atom or a methyl group. However, when La ²¹ is −O−, Ya ²¹ is not −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 of Ya ²¹ is not particularly limited, and examples thereof include a divalent hydrocarbon group which may have a substituent and a divalent linking group containing a heteroatom. As a divalent hydrocarbon group which may have a substituent in Ya ²¹ and a divalent linking group containing a hetero atom, it has a substituent in Va ¹ in the above formula (a1-1). Examples thereof include a divalent hydrocarbon group and a divalent linking group containing a hetero atom.
In the present embodiment, the Ya ²¹ is a single bond, an ester bond [-C (= O) -O-], an ether bond (-O-), a linear or branched alkylene group, or a combination thereof. Is preferable.

The “lactone-containing cyclic group” refers to a cyclic group containing a ring (lactone ring) containing −OC (= O) − in its cyclic skeleton. The lactone ring is counted as the first ring, and when it has only a lactone 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 lactone-containing cyclic group may be a monocyclic group or a polycyclic group.
As the lactone-containing cyclic group, any one can be used without particular limitation. Specific examples thereof include groups represented by the following general formulas (a2-r-1) to (a2-r-7). 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 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, hydroxyl group, -COOR - in ", OC (= O) R ", a hydroxyalkyl group or a cyano group Yes; 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. And m'is 0 or 1. ]

In the general formulas (a2-r-1) to (a2-r-7), A "may contain an oxygen atom (-O-) or a sulfur atom (-S-) and has 1 to 5 carbon atoms. 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, etc. Examples include an isopropylene group. When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include a group in which -O- or -S- is interposed between the terminal or carbon atom of the alkylene group, for example, -O-CH _{2. -, - CH 2 -O-CH} 2 -, - S-CH 2 -, - CH 2 -S-CH 2 - , and the like. The A ", alkylene group or -O- is preferable of 1 to 5 carbon atoms, more preferably an alkylene group having 1 to 5 carbon atoms, the most preferred .ra ^'21 are each independently a methylene group, an alkyl group, an alkoxy It is a group, a halogen atom, an alkyl halide group, -COOR ", -OC (= O) R", a hydroxyalkyl group or a cyano group.
The alkyl group in ra ^'21, preferably an alkyl group having 1 to 5 carbon atoms.
The alkoxy group in the ra ^'21, preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, groups of the the Ra 'group and an oxygen atom mentioned as the alkyl group in ²¹ (-O-) are linked and the like.
As the halogen atom in ra ^'21, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, 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 alkyl halide group, an alkyl fluorinated group is preferable, and a perfluoroalkyl group is particularly preferable.

Specific examples of the groups represented by the general formulas (a2-r-1) to (a2-r-7) are given 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 cyclic skeleton of the cyclic group. A ring containing −SO ₂ − in its ring skeleton is counted as the first ring, and if it is only the ring, it is a monocyclic group, and if it has another ring structure, it is a polycyclic group regardless of its structure. It is called. The −SO ₂ − containing cyclic group may be monocyclic or polycyclic.
-SO ₂ - containing cyclic group, in particular, -O-SO ₂ - within the ring skeleton cyclic group containing, i.e. -O-SO ₂ - -O-S- medium is a part of the ring skeleton It is preferably a cyclic group containing a sultone ring to be formed. -SO ₂ - containing cyclic group, and more specifically, include groups respectively represented by the following formula (a5-r-1) ~ (a5-r-4).

［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 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, hydroxyl group, -COOR - in ", OC (= O) R ", a hydroxyalkyl group or a cyano group Yes; 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 of. ]

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. .. Alkyl group in ra ^'51, an alkoxy group, a halogen atom, a halogenated alkyl group, -COOR ", - OC (= O) R", The hydroxyalkyl group, the above general formula (a2-r-1) ~ ( it is the same as a2-r-7) in the Ra ^'21.

Specific examples of the groups represented by the general formulas (a5-r-1) to (a5-r-4) are given below. "Ac" in the formula indicates an acetyl group.

The "carbonate-containing cyclic group" refers to a cyclic group containing a ring (carbonate ring) containing -OC (= O) -O- in its cyclic 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 a monocyclic group or a polycyclic group.
As the carbonate ring-containing cyclic group, any one can be used without particular limitation. Specifically, the groups represented by the following general formulas (ax3-r-1) to (ax3-r-3) can be mentioned.

［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。］

[In the formula, ^Ra'x31 is independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, an alkyl halide group, a hydroxyl group, -COOR ", -OC (= O) R", a hydroxyalkyl group or a cyano group. Yes; 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. And q'is 0 or 1. ]

The A "in the general formulas (ax3-r-1) to (ax3-r-3) is the same as the A" in the general formula (a2-r-1).
The alkyl group, alkoxy group, halogen atom, alkyl halide group, -COOR ", -OC (= O) R", and hydroxyalkyl group in ^Ra'x31 are the above general formulas (a2-r-1) to (1), respectively. a2-r-7) as in the same as those exemplified in the description of the Ra ^'21 of the like.

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

The structural unit (a2) contained in the component (A1) may be one type or two or more types.
When the component (A1) has a constituent unit (a2), the ratio of the constituent unit (a2) is preferably 1 to 80 mol% with respect to the total of all the constituent units constituting the component (A1). It is more preferably 5 to 70 mol%, further preferably 10 to 65 mol%, and particularly preferably 10 to 60 mol%.
By setting the ratio of the constituent unit (a2) to the lower limit value or more, the effect of containing the constituent unit (a2) can be sufficiently obtained, and by setting the ratio to the upper limit value or less, the balance with other constituent units can be obtained. The various lithography characteristics such as DOF and CDU and the pattern shape are improved.

Structural unit (a3):
The structural unit (a3) is a structural unit containing a polar group-containing aliphatic hydrocarbon group (however, excluding those corresponding to the above-mentioned structural units (a1) and (a2)).
It is considered that the component (A1) having the constituent unit (a3) enhances the hydrophilicity of the component (A) and contributes to the improvement of the resolution.
Examples of the polar group in the structural unit (a3) include a hydroxyl group, a cyano group, a carboxy group, a hydroxyalkyl group in which a part of hydrogen atoms of the 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, in the resin for the resist composition for ArF excimer laser, it can be appropriately selected and used from a large number of proposed ones. 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 acrylic acid 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 a group obtained by removing two or more hydrogen atoms from a bicycloalkane, a tricycloalkane, a tetracycloalkane, or the like. Specific examples thereof include groups obtained by removing two or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, a group in which two or more hydrogen atoms are removed from adamantane, a group in which two or more hydrogen atoms are removed from norbornane, and a group in which two or more hydrogen atoms are removed from tetracyclododecane are used. Industrially preferable.

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 acrylic acid ester in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent and contains a polar group-containing aliphatic hydrocarbon group. Constituent 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 the hydroxyethyl ester of acrylic acid. When the hydrocarbon group is a polycyclic group, the structural unit represented by the following formula (a3-1), the structural unit represented by the formula (a3-2), and the formula ( The structural unit represented by a3-3) is preferably mentioned.

［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 1-3, k is an integer of 1-3, t'is an integer of 1-3, and l is an integer of 1-5. And s is an integer of 1-3. ]

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 group is bonded to the 3- and 5-positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group.
j is preferably 1, and in particular, the hydroxyl group is preferably bonded to the 3-position of the adamantyl group.

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

In formula (a3-3), t'is preferably 1. l is preferably 1. s is preferably 1. In these, it is preferable that a 2-norbornyl group or a 3-norbornyl group is bonded to the terminal of the carboxy group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5 or 6 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 a constituent unit (a3), the ratio of the constituent unit (a3) is preferably 5 to 50 mol% with respect to the total of all the constituent units constituting the component (A1). 5 to 40 mol% is more preferable, and 5 to 25 mol% is even more preferable.
By setting the ratio of the constituent unit (a3) to the lower limit value or more, the effect of containing the constituent unit (a3) can be sufficiently obtained, and by setting it to the upper limit value or less, the balance with other constituent units can be obtained. It will be easier.

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

Structural unit (a4):
The structural unit (a4) is a structural unit containing an acid non-dissociative cyclic group. Since the component (A1) has the structural unit (a4), the dry etching resistance of the resist pattern to be formed is improved. In addition, the hydrophobicity of the component (A1) is increased. The improvement of hydrophobicity is considered to contribute to the improvement of resolution, resist pattern shape, etc., especially in the case of organic solvent development.
The "acid non-dissociative cyclic group" in the structural unit (a4) is contained in the structural unit as it is without dissociation even if the acid acts when an acid is generated from the component (B) described later by exposure. The remaining cyclic group.
As the structural unit (a4), for example, a structural unit derived from an acrylic acid ester containing an acid non-dissociative aliphatic cyclic group is preferable. As the cyclic group, for example, the same ones as those exemplified in the case of the above-mentioned structural unit (a1) can be exemplified, such as for ArF excimer laser, for KrF excimer laser (preferably for ArF excimer laser), and the like. Many conventionally known ones used for the resin component of the resist composition of the above can be used.
In particular, at least one selected from a tricyclodecyl group, an adamantyl group, a tetracyclododecyl group, an isobornyl group, and a norbornyl group is preferable in that it is easily available industrially. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
As the structural unit (a4), specifically, those represented by the following general formulas (a4-1) to (a4-7) can be exemplified.

［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 a constituent unit (a4), the ratio of the constituent unit (a4) is preferably 1 to 30 mol% with respect to the total of all the constituent units constituting the component (A1). More preferably, it is ~ 20 mol%.

The component (A1) is preferably a polymer having a structural unit (a1), and in particular, a copolymer having a structural unit (a1), a structural unit (a2) and a structural unit (a3). preferable.

The component (A1) is obtained by polymerizing a monomer that induces each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate. be able to.
Further, the component (A1), during the polymerization, by using a combination of chain transfer agent such as _{HS-CH 2 -CH 2 -CH 2} -C (CF 3) 2 -OH, end -C (CF ₃ ) _2- OH group may be introduced into the. In this way, the copolymer in which the hydroxyalkyl group in which a part of the hydrogen atom of the alkyl group is replaced with the fluorine atom is introduced can reduce development defects and LER (line edge roughness: non-uniform unevenness of the line side wall). It 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. Most preferably 2000 to 20000.
If it is not more than the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is more than the lower limit of this range, the dry etching resistance and the resist pre-pattern cross-sectional shape are good. ..

In the resist composition, one type of component (A1) may be used alone, or two or more types may be used in combination.
The ratio of the component (A1) to the base material component (A) is preferably 25% by mass or more, more preferably 50% by mass, still more preferably 75% by mass, and 100% by mass, based on the total mass of the base material component (A). It may be% by mass. When the ratio is 25% by mass or more, the lithography characteristics are further improved.

In the resist composition, one type of component (A) 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) (hereinafter referred to as “component (B)”) that generates an acid upon exposure.
The component (B) is not particularly limited, and those previously proposed as an acid generator for a chemically amplified resist can be used.
Examples of such an acid generator include onium salt-based acid generators such as iodonium salt and sulfonium salt, oxime sulfonate-based acid generators, bisalkyl or bisarylsulfonyldiazomethanes, and diazomethanes such as poly (bissulfonyl) diazomethanes. Various kinds such as an acid generator, a nitrobenzyl sulfonate-based acid generator, an imino sulfonate-based acid generator, and a disulfon-based acid generator can be mentioned. Of 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 “(b-2) component”) or a compound represented by the 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^１０８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 the formula, R ¹⁰¹ and R ^{104 to} R ¹⁰⁸ each have a cyclic group that may independently have a substituent, a chain alkyl group that may have a substituent, or a substituent. It is a chain alkenyl group that may be present. R ¹⁰⁴ and R ¹⁰⁵ may be coupled to each other to form a ring. Any two of R ^{106 to} R ¹⁰⁸ may be coupled 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 independently single bonds, alkylene groups, or fluorinated alkylene groups, respectively. L ^{101 to} L ¹⁰² are independently single bonds or oxygen atoms, respectively. L ¹⁰³ ~L ¹⁰⁵ are each independently a single bond, -CO- or -SO ₂ - is. ^{M'm +} is an m-valent organic cation. ]

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

A 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. It may be an aliphatic hydrocarbon group.
The aromatic hydrocarbon group in R ¹⁰¹ is the aromatic hydrocarbon ring mentioned in the divalent aromatic hydrocarbon group in Va ¹ in the above formula (a1-1), or an aromatic compound containing two or more aromatic rings. An aryl group obtained by removing one hydrogen atom from the group is mentioned, and a phenyl group and a naphthyl group are preferable.
The cyclic aliphatic hydrocarbon group in R ¹⁰¹ was obtained by removing one hydrogen atom from the monocycloalkane or polycycloalkane listed in the divalent aliphatic hydrocarbon group in Va ¹ in the above formula (a1-1). Examples thereof include an adamantyl group and a norbornyl group, which are preferable.
Further, the cyclic hydrocarbon group in R ¹⁰¹ may contain a hetero atom such as a heterocycle, and specifically, each of them is represented by the above general formulas (a2-r-1) to (a2-r-7). Lactone-containing cyclic groups, -SO ₂ -containing cyclic groups represented by the above general formulas (a5-r-1) to (a5-r-4), and the following chemical formulas (r-hr-1) to Examples thereof include heterocyclic groups represented by (r-hr-16).

Examples of the substituent in the cyclic hydrocarbon group of R ¹⁰¹ include an alkyl group, an alkoxy group, a halogen atom, an alkyl halide group, a hydroxyl group, a carbonyl group, a nitro group and the like.
As the alkyl group as the substituent, an alkyl group having 1 to 5 carbon atoms is preferable, and a methyl group, an ethyl group, a propyl group, an n-butyl group and a tert-butyl group are most preferable.
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 more preferable, and methoxy. Groups and ethoxy groups are most preferred.
Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.
As the alkyl halide group as a substituent, a part 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, and a tert-butyl group are described above. Examples include groups substituted with halogen atoms.

Chain-shaped alkyl group which may have a substituent on R ¹⁰¹ The chain-shaped alkyl group of 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. Examples thereof include a group, a pentadecyl group, a hexadecyl group, an isohexadecyl group, a heptadecyl group, an octadecyl group, a nonadecil group, an icosyl group, a henicosyl group, a 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, Examples thereof include 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group and 4-methylpentyl group.

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 Of the above, 2 to 5 are more preferable, 2 to 4 are even more preferable, and 3 is particularly preferable. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group), a butynyl group and the like. Examples of the branched chain alkenyl group include a 1-methylpropenyl group and a 2-methylpropenyl group.
Among the above, the propenyl group is particularly preferable as the chain alkenyl group.

Examples of the substituent in the chain alkyl group or alkenyl group of R ¹⁰¹ include an alkoxy group, a halogen atom, an alkyl halide group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, and a cyclic group in R ¹⁰¹ . 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, are represented by the above general formulas (a2-r-1) to (a2-r-7), respectively. lactone-containing cyclic group, -SO ₂ respectively represented by the general formula (a5-r-1) ~ (a5-r-4) - containing cyclic group and the like.

In formula (b-1), Y ¹⁰¹ is a divalent linking group containing a single bond or an oxygen atom.
When Y ¹⁰¹ is a divalent linking group containing an oxygen atom, the Y ¹⁰¹ may contain an atom other than the oxygen atom. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, sulfur atoms, nitrogen atoms and the like.
Examples of the divalent linking group containing an oxygen atom include an oxygen atom (ether bond: −O−), an ester bond (−C (= O) −O−), and an oxycarbonyl group (−OC (= O−). )-), Amid bond (-C (= O) -NH-), carbonyl group (-C (= O)-), carbonate bond (-O-C (= O) -O-) and other non-carbohydrates Oxygen atom-containing linking group of the system; Examples thereof include a combination of the oxygen atom-containing linking group of the non-hydrogen system 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), respectively.

［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。］

Wherein, V ^'101 represents a single bond or an alkylene group having 1 to 5 carbon atoms, V' ¹⁰² is a divalent saturated hydrocarbon group having 1 to 30 carbon atoms. ]

Divalent saturated hydrocarbon group in V ^'102 is preferably an alkylene group having 1 to 30 carbon atoms.

The alkylene group for V ^'101 and V' ^102, may be linear well branched alkylene group with an alkylene group, 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) -, - C (CH 3) Alkylmethyl groups such as _2- , -C (CH ₃ ) (CH ₂ CH ₃ )-, -C (CH ₃ ) (CH ₂ CH ₂ CH ₃ )-, -C (CH ₂ CH ₃ ) _2-, etc.; 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 ) Alkylethylene groups 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 ) Alkylmethylethylene groups such as CH _2- ; tetramethylene groups [-CH ₂ CH ₂ CH ₂ CH _2- ]; -CH (CH ₃ ) CH ₂ CH ₂ CH _2- , -CH ₂ CH (CH ₃ ) CH ₂ Alkyltetramethylene groups such as CH _2- ; pentamethylene groups [-CH ₂ CH ₂ CH ₂ CH ₂ CH _2- ] and the like can be mentioned.
A part of the methylene groups in the alkylene group for V ^'101 or V' ¹⁰² may be substituted by a divalent aliphatic cyclic group having 5 to 10 carbon atoms. The aliphatic cyclic group, the formula (a1-r-1) 2 monovalent group further one except a hydrogen atom from an aliphatic hydrocarbon group of Ra ^'3 annular in preferably, cyclohexylene group , 1,5-adamantylene group or 2,6-adamantylene group is more preferable.

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

In formula (b-1), V ¹⁰¹ is a single bond, an alkylene group, or a fluorinated alkylene group. The alkylene group and the fluorinated alkylene group in V ¹⁰¹ preferably have 1 to 4 carbon atoms. ^Examples of the fluorinated alkylene group in V ¹⁰¹ include a group in which a part or all of hydrogen atoms of the alkylene group in V ¹⁰¹ are substituted with a fluorine atom. 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.

Specific examples of the anion portion of the component (b-1) include fluorinated alkyl sulfonate anions such as trifluoromethanesulfonate anion and perfluorobutane sulfonate anion when Y ¹⁰¹ is a single bond; 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、前記一般式（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 the above formulas (r-hr-1) to (r-hr-6), or a substitution. It is a chain alkyl group which may have a group; R " ¹⁰² is an aliphatic cyclic group which may have a substituent, the general formulas (a2-r-1) to (a2-). lactone-containing cyclic group represented respectively by r-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. V " ¹⁰¹ is a fluorinated alkylene group; L" ¹⁰¹ is -C (= O)-or -SO _2- ; v "is an independently integer of 0 to 3, q. "Is an integer of 1 to 20 independently, and n" is 0 or 1. ]

The aliphatic cyclic group which may have the substituents of R " ¹⁰¹ , R" ¹⁰² and R " ¹⁰³ is preferably the group exemplified as the cyclic aliphatic hydrocarbon group in R ¹⁰¹ . Examples of the substituent include the same substituents which may substitute the cyclic aliphatic hydrocarbon group in R ¹⁰¹ .

The aromatic cyclic group which may have a substituent in R " ¹⁰³ is preferably a group exemplified as an aromatic hydrocarbon group in the cyclic hydrocarbon group in R ^101. The substituent is preferably a group. , R ¹⁰¹ , the same as the substituent which may replace the aromatic hydrocarbon group.

The chain-like alkyl group which may have a substituent at R " ¹⁰¹ is preferably the group exemplified as the chain-like alkyl group at R ^{101. It} has a substituent at R " ¹⁰³ . The good chain alkenyl group is preferably the group exemplified as the chain alkenyl group in R ¹⁰¹ . V ^"101 is preferably a fluorinated alkylene group having 1 to 3 carbon atoms, particularly _{preferably, -CF 2 -, - CF 2} CF 2 -, - CHFCF 2 -, - CF (CF 3) CF 2 - , -CH (CF ₃ ) CF _2- .

-In the anion part formula (b-2) of the component (b-2), R ¹⁰⁴ and R ¹⁰⁵ may independently have a substituent, even if they have a cyclic group and a substituent. Examples thereof include a good chain alkyl group and a chain alkenyl group which may have a substituent, respectively, which are similar to R ¹⁰¹ in the formula (b-1). However, R ¹⁰⁴ and R ¹⁰⁵ may be coupled to each other to form a ring.
R ¹⁰⁴ and R ¹⁰⁵ are preferably chain-like alkyl groups which may have a substituent, and are linear or branched-chain alkyl groups, or linear or branched-chain fluorinated alkyl groups. Is more preferable.
The chain 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 because the solubility in the resist solvent is also good within the range of the carbon number. Further, in the chain alkyl groups of R ¹⁰⁴ and R ^105, the larger the number of hydrogen atoms substituted with fluorine atoms, the stronger the acid strength, and the stronger the acid strength, and the higher the strength of the acid with respect to high-energy light or electron beam of 200 nm or less. It is preferable because it improves transparency. The ratio of fluorine atoms in the chain alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all hydrogen atoms are substituted with fluorine atoms. It is a perfluoroalkyl group.
In formula (b-2), V ¹⁰² and V ¹⁰³ are independently single bonds, alkylene groups, or fluorinated alkylene groups, respectively, and the same as V ¹⁰¹ in formula (b-1), respectively. Can be mentioned.
In formula (b-2), L ^{101 to} L ¹⁰² are independently single bonds or oxygen atoms, respectively.

-In the anion part formula (b-3) of the component (b-3), R ^{106 to} R ¹⁰⁸ may independently have a substituent, even if they have a cyclic group or a substituent. Examples thereof include a good chain alkyl group and a chain alkenyl group which may have a substituent, respectively, which are similar to R ¹⁰¹ in the formula (b-1).
L ^{103 to} L ¹⁰⁵ are each independently single-bonded, -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 is used. 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 represent aryl groups, alkyl groups or alkenyl groups, which may have independent substituents, respectively, and R ^{201 to} R ²⁰³ and R ²⁰⁶ to R ²⁰⁶ . R ²⁰⁷ and R ^{211 to} R ²¹² may be bonded to each other to form a ring together 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 contains an aryl group, an alkyl group, an alkenyl group, or -SO _2- which may have a substituent. It is a cyclic group, L ²⁰¹ represents −C (= O) − or −C (= O) −O−, Y ²⁰¹ independently represents an arylene group, an alkylene group or an alkenylene group, and x is 1 or 2, where W ²⁰¹ represents a (x + 1) valence 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 groups in R ^{201 to} R ²⁰⁷ and R ^{211 to} R ²¹² are preferably chain or cyclic alkyl groups having 1 to 30 carbon atoms.
The alkenyl group in R ^{201 to} R ²⁰⁷ and R ^{211 to} R ²¹² preferably has 2 to 10 carbon atoms.
Substituents that R ^{201 to} R ²⁰⁷ and R ^{210 to} R ²¹² may have include, for example, an alkyl group, a halogen atom, an alkyl halide group, a carbonyl group, a cyano group, an amino group, an aryl group, and an arylthio. Examples include groups represented by the following formulas (ca-r-1) to (ca-r-7), respectively.
The aryl group in the arylthio group as a substituent is the same as that mentioned in R ¹⁰¹ , and specific examples thereof include a phenylthio group and 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, ^R'201 is independently a hydrogen atom, a cyclic group which may have a substituent, a chain alkyl group, or a chain alkenyl group. ]

R ^'201 which may have a substituent cyclic group, substituent having optionally also good chain alkyl group or have a substituent which may chain alkenyl groups, is the In addition to the same as R ¹⁰¹ in the formula (b-1), the above formula (b) is used as a cyclic group which may have a substituent or a chain alkyl group which may have a substituent. The same as the acid dissociable group represented by a1-r-2) can also be mentioned.

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 together with the sulfur atom in the formula, heteroatoms such as sulfur atom, oxygen atom, and nitrogen atom, and heteroatoms such as sulfur atom and nitrogen atom, and 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. It may be bonded via a functional group of. As the ring to be formed, one ring containing a sulfur atom in its ring skeleton, including the sulfur atom, is preferably a 3 to 10-membered ring, and particularly preferably a 5- to 7-membered ring. preferable. Specific examples of the ring to be formed include, for example, a thiophene ring, a thiazole ring, a benzothiophene ring, a thianthrene ring, a benzothiophene ring, a dibenzothiophene ring, a 9H-thioxanthene ring, a thioxanthone ring, a thianthrene ring, a phenoxatiin ring, and a 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 are alkyl groups, 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 a substituent. -SO ₂ -containing cyclic group.
^Examples of the aryl group in 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 in R ²¹⁰ is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms.
The alkenyl group in 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 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 independently represents an arylene group, an alkylene group or an alkenylene group.
Examples of the arylene group in Y ²⁰¹ include a group obtained by removing one hydrogen atom from the aryl group exemplified as the aromatic hydrocarbon group in R ¹⁰¹ in the above formula (b-1).
Examples of the alkylene group and the alkenylene group in Y ²⁰¹ include the same as the aliphatic hydrocarbon group as the divalent hydrocarbon group in Va ¹ in the above general formula (a1-1).

In the formula (ca-4), x is 1 or 2.
W ²⁰¹ is a (x + 1) valence, i.e., a divalent or trivalent linking group.
As the divalent linking group in W ^{201, a} divalent hydrocarbon group which may have a substituent is preferable, and a hydrocarbon group similar to Ya ²¹ in the general formula (a2-1) can be exemplified. The divalent linking group in 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 in W ²⁰¹ include a group obtained by removing one hydrogen atom from the divalent linking group in W ²⁰¹ , and a group in which the divalent linking group is further bonded to the divalent linking group. Can be mentioned. As the trivalent linking group in W ²⁰¹ , a group in which two carbonyl groups are bonded to an arylene group is preferable.

Specific examples of suitable cations 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 the formula, g1, g2, and g3 indicate the number of repetitions, g1 is an integer of 1 to 5, g2 is an integer of 0 to 20, and g3 is an integer of 0 to 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 substituents are the same as those listed as the substituents that R ^{201 to} R ²⁰⁷ and R ^{210 to} R ²¹² may have. is there.]

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

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

As the component (B), the above-mentioned acid generator may be used alone or in combination of two or more.
When the resist composition contains the component (B) in the present embodiment, the content of the component (B) is preferably 0.5 to 60 parts by mass, preferably 1 to 50 parts by mass with respect to 100 parts by mass of the component (A). Parts are more preferable, and 1 to 40 parts by mass are further preferable.
By setting the content of the component (B) in 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 is improved, which is preferable.

≪Other ingredients≫
In the present embodiment, the resist composition may further contain other components in addition to the component (A) or in addition to the components (A) and (B).
Examples of other components include (D) component, (E) component, (F) component, and (S) component, which will be described later.

Ingredient (D):
In the present embodiment, the resist composition may further contain an acid diffusion control agent component (hereinafter, also referred to as “(D) component”).
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 photodisintegrating base (D1) (hereinafter referred to as “component (D1)”) that is decomposed by exposure and loses acid diffusion controllability, and the component (D1). It may be a nitrogen-containing organic compound (D2) (hereinafter, referred to as “(D2) component”) that does not correspond to the above.

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

［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 have 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. Alkyl group of. However, it is assumed that the fluorine atom is not bonded to the carbon atom adjacent to the S atom in Rd ² in the formula (d1-2). Yd ¹ is a single bond or divalent linking group. M ^{m +} are independently m-valent organic cations. ]

{(D1-1) component}
.. In the anion part 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. It is a chain alkenyl group which may be the same as that of 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. Chained hydrocarbon groups are preferred. As the substituent which these groups may have, a hydroxyl group, a fluorine atom or a fluorinated alkyl group is preferable.
As the aromatic hydrocarbon group, a phenyl group or a naphthyl group is more preferable.
The aliphatic cyclic group is more preferably a group obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
As the chain hydrocarbon group, a chain alkyl group is preferable. The chain alkyl group preferably has 1 to 10 carbon atoms, and specifically, 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. Linear alkyl groups such as groups and decyl groups; 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 other branched alkyl groups;

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

A preferable specific example of the anion portion of the component (d1-1) is shown below.

.. In the cation part equation (d1-1), M ^{m +} is an m-valent organic cation.
The organic cation of M ^{m +} is not particularly limited, and examples thereof include the same cations represented by the general formulas (ca-1) to (ca-4), respectively, and the formula (ca-1-). The 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}
In the anion part formula (d1-2), Rd ² has 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 which may be present, and examples thereof include the same group as R ¹⁰¹ .
However, it is assumed that the carbon atom adjacent to the S atom in Rd ² does not have a fluorine atom bonded (fluorine-substituted). As a result, 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); It is more preferable that it is a group obtained by removing one or more hydrogen atoms from a camphor or the like.
The hydrocarbon group of Rd ² may have a substituent, and the substituent may be a hydrocarbon group (aromatic hydrocarbon group, aliphatic hydrocarbon group) in Rd ¹ of the above formula (d1-1). Examples include those similar to the substituents that may have.

A preferable specific example of the anion portion of the component (d1-2) is shown below.

· · In the cation part formula (d1-2), M ^{m +} is an m-valent organic cation, which is the same as M ^{m +} 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}
.. In the anion part formula (d1-3), Rd ³ has a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a substituent. It may be a chain alkenyl group, the same as that of R ^101, and is preferably a cyclic group containing a fluorine atom, a chain alkyl group, or a chain alkenyl group. Of these, an alkyl fluorinated group is preferable, and the same group as the alkyl fluorinated group of 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 the same group as R ¹⁰¹ can be mentioned.
Of these, alkyl groups, alkoxy groups, alkenyl groups, and cyclic groups that may have a substituent are preferable.
The alkyl group in Rd ⁴ is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, or an isobutyl group. , Tert-Butyl group, pentyl group, isopentyl group, neopentyl group and the like. A part of the hydrogen atom of the alkyl group of Rd ⁴ may be substituted with a hydroxyl group, a cyano group or the like.
The alkoxy group in Rd ⁴ is preferably an alkoxy group having 1 to 5 carbon atoms, and specifically, the alkoxy group having 1 to 5 carbon atoms is a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, or n-. Examples thereof include a butoxy group and a tert-butoxy group. Of these, a methoxy group and an ethoxy group are preferable.

Examples of the alkenyl group in Rd ⁴ include those similar to those in 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 an alkyl group having 1 to 5 carbon atoms or an alkyl halide group having 1 to 5 carbon atoms as a substituent.

Examples of the cyclic group in Rd ⁴ include those similar to those in R ¹⁰¹ above, and one or more hydrogen atoms are removed from cycloalkanes such as cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. An alicyclic group or an aromatic group such as a phenyl group or a naphthyl group is preferable. When Rd ⁴ is an alicyclic group, the resist composition is well dissolved in an organic solvent, so that the lithography characteristics are improved. Further, when Rd ⁴ is an aromatic group, the resist composition has excellent light absorption efficiency and good sensitivity and lithography characteristics in lithography using EUV or the like as an exposure light source.

In formula (d1-3), Yd ¹ is a single bond or a divalent linking group.
The divalent linking group in Yd ¹ is not particularly limited, but includes a divalent hydrocarbon group (aliphatic hydrocarbon group, aromatic hydrocarbon group) which may have a substituent and a hetero atom 2 Examples include valuation linkage groups. Examples of these are the same as those mentioned in the description of the divalent linking group of Ya ²¹ in the above 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, and even more preferably a methylene group or an ethylene group.

A preferable specific example of the anion portion of the component (d1-3) is shown below.

· · In the cation part formula (d1-3), M ^{m +} is an m-valent organic cation, which is the same as M ^{m +} in the above 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 of the above components (d1-1) to (d1-3) may be used, or two or more of them 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). It is more preferably parts by mass.
When the content of the component (D1) is at least a preferable lower limit value, particularly good lithography characteristics and resist pattern shape can be obtained. On the other hand, when it is not more than the upper limit value, good sensitivity can be maintained and throughput is also excellent.

The method for producing the above-mentioned components (d1-1) and (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, and more preferably 0.5 to 8.0 parts by mass with respect 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 of the above range, particularly good lithography characteristics and resist pattern shape can be obtained. When it is not more than the upper limit value of the above range, the sensitivity can be maintained well and the throughput is also excellent.

-Component (D2) The component (D) may contain a nitrogen-containing organic compound component (hereinafter referred to as "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 control agent and does not correspond to the component (D1), and any known component may be used. Of these, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines, are preferable.
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) in which at least one hydrogen atom of ammonia NH ₃ is replaced with an alkyl group or a hydroxyalkyl group having 12 or less carbon atoms, or a cyclic amine.
Specific examples of alkylamines and alkylalcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di. 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 other trialkylamines; diethanolamine, triethanolamine, diisopropanolamine, tri Alkyl alcohol amines such as isopropanolamine, di-n-octanolamine and tri-n-octanolamine can be mentioned. Among these, trialkylamines having 5 to 10 carbon atoms are 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, and tris {2. -(1-methoxyethoxy) ethyl} amine, tris {2- (1-ethoxyethoxy) ethyl} amine, tris {2- (1-ethoxypropoxy) ethyl} amine, tris [2- {2- (2-hydroxy) Examples thereof include ethoxy) ethoxy} ethyl] amine and triethanolamine triacetate, and triethanolamine triacetate is preferable.

Further, as the component (D2), an aromatic amine may be used.
Aromatic amines include aniline, pyridine, 4-dimethylaminopyridine, pyrrole, indol, pyrazole, imidazole or derivatives thereof, diphenylamine, triphenylamine, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxy. Examples thereof include carbonylpyrrolidine.

The component (D2) may be used alone or in combination of two or more.
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). Within the above range, the shape of the resist pattern, stability over time, 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.
When the resist composition contains the component (D) in the present embodiment, the component (D) is preferably 0.1 to 15 parts by mass with respect to 100 parts by mass of the component (A), and is 0.3. It is more preferably ~ 12 parts by mass, and further preferably 0.5 to 12 parts by mass.
When it is at least the lower limit of the above range, the lithography characteristics such as LWR are further improved when the resist composition is prepared. Moreover, a better resist pattern shape can be obtained. When it is not more than the upper limit value of the above range, the sensitivity can be maintained well and the throughput is also excellent.

(E) Ingredient:
In the present embodiment, the resist composition contains an organic carboxylic acid, an oxo acid of phosphorus and a derivative thereof as optional components for the purpose of preventing deterioration of sensitivity, improving the shape of the resist pattern, stability over time, and the like. At least one compound (E) selected from the group consisting of (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 the oxo acid of phosphorus include phosphoric acid, phosphonic acid, phosphinic acid and the like, and among these, phosphonic acid is particularly preferable.
Examples of the derivative of the oxo acid of phosphorus include an ester in which the hydrogen atom of the oxo acid is replaced with a hydrocarbon group, and the hydrocarbon group includes an alkyl group having 1 to 5 carbon atoms and 6 to 6 carbon atoms. Examples include 15 aryl groups.
Examples of the phosphoric acid derivative include phosphoric acid esters such as phosphoric acid di-n-butyl ester and phosphoric acid diphenyl ester.
Examples of the phosphonic acid derivative include phosphonic acid esters such as 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) include JP-A-2010-002870, JP-A-2010-032994, JP-A-2010-277043, JP-A-2011-13569, and JP-A-2011-128226. The described fluorine-containing polymer compound can be used.
More specifically, as the component (F), a polymer having a structural unit (f1) represented by the following formula (f1-1) can be mentioned. The polymer is a polymer (copolymer) consisting of only 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 constituent unit (a1); the constituent unit (f1) represented by the following formula (f1-1), the constituent unit derived from acrylic acid or methacrylic acid, and the constituent unit (a1). Copolymer: A copolymer of a structural unit (f1) represented by the following formula (f1-1) and the structural unit (a4) is preferable.
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 and 2-methyl- 2-adamantyl (meth) acrylate or a structural unit represented by the above formula (a1-2-01) is preferable.
The structural unit (a4) copolymerized with the structural unit (f1) represented by the following formula (f1-1) is a configuration represented by the general formulas (a4-1) to (a4-5), respectively. The unit 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 described above, and Rf ¹⁰² and Rf ¹⁰³ independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkyl halide group having 1 to 5 carbon atoms, respectively. 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 the formula (f1-1), R is the same as described above. As R, a hydrogen atom or a methyl group is preferable.
In the formula (f1-1), examples of the halogen atom of Rf ¹⁰² and Rf ¹⁰³ include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is particularly preferable. Examples of the alkyl group having 1 to 5 carbon atoms of Rf ¹⁰² and Rf ¹⁰³ include those similar to the above-mentioned alkyl group having 1 to 5 carbon atoms of R, and a methyl group or an ethyl group is preferable. As the alkyl halide group having 1 to 5 carbon atoms of Rf ¹⁰² and Rf ¹⁰³ , specifically, 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 is used. Can be mentioned. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is particularly preferable. Among them, as Rf ¹⁰² and Rf ¹⁰³ , a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms is preferable, and a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group is preferable.
In the 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 the formula (f1-1), Rf ¹⁰¹ is preferably an organic group containing a fluorine atom and preferably a hydrocarbon group containing a fluorine atom.
The hydrocarbon group containing a fluorine atom may be linear, branched or cyclic, and preferably has 1 to 20 carbon atoms, and more preferably 1 to 15 carbon atoms. , 1 to 10 carbon atoms are particularly preferable.
Further, as for the hydrocarbon group containing a fluorine atom, it is preferable that 25% or more of the hydrogen atoms in the hydrocarbon group are fluorinated, more preferably 50% or more is fluorinated, and 60% or more is fluorinated. It is particularly preferable that it is fluorinated because the hydrophobicity of the resist film during immersion exposure is increased.
Among ^these, as ^{Rf 101,} particularly preferably a fluorinated hydrocarbon group having 1 to 6 carbon atoms, a methyl _{group, -CH 2 -CF 3, -CH 2} -CF 2 -CF 3, -CH (CF 3) 2 , -CH _2- CH _2- CF ₃ , -CH _2- CH _2- CF _2- CF _2- CF _2- CF ₃ are most preferable.

The weight average molecular weight (Mw) of the component (F) (polystyrene conversion standard by gel permeation chromatography) is preferably 1000 to 50000, more preferably 5000 to 40,000, and most preferably 1000 to 30000. When it is not more than the upper limit value of this range, it has sufficient solubility in a resist solvent to be used as a resist, and when it is more than the lower limit value of this range, the dry etching resistance and the cross-sectional shape of the resist pattern 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 ratio 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 is further optionally miscible with additives such as additional resins for improving the performance of resist films, dissolution inhibitors, plasticizers, stabilizers, colorants, anti-halation. Agents, dyes and the like can be appropriately added and contained.

(S) component:
In the present embodiment, the resist composition can be produced by dissolving the material in an organic solvent (hereinafter, also referred to as “component (S)”).
The component (S) may be any component as long as it can dissolve each component to be used to form a uniform solution, and any one of those conventionally known as a solvent for chemically amplified resist may be used. Two or more types 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), methyl isopentyl ketone, etc .; ethylene glycol, diethylene glycol, propylene glycol, di Polyhydric alcohols such as propylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, or dipropylene glycol monoacetate, the polyhydric alcohols or the compound having the ester bond. Derivatives of polyhydric alcohols such as monoalkyl ethers such as monomethyl ethers, monoethyl ethers, monopropyl ethers and monobutyl ethers, or compounds having an ether bond such as monophenyl ethers [among these, propylene glycol monomethyl ether acetate (PGMEA) ), Propylene glycol monomethyl ether (PGME)]; 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, ethyl ethoxypropionate; anisole, ethylbenzyl ether, cresylmethyl ether, diphenyl ether, dibenzyl ether, phenetol, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, Examples thereof include aromatic organic solvents such as cymen and mesityrene, and dimethyl sulfoxide (DMSO).
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.
Further, a mixed solvent in which PGMEA and a polar solvent are mixed is also preferable. The blending 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 even more preferably 3: 7 to 7 :. It is 3.
In addition, 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, the mass ratio of the former and the latter is preferably 70:30 to 95: 5 as the mixing ratio.
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.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

<Manufacturing of resin components>
[Synthesis of Polymer Compound (P) -1]
0.239 g (5.64 mmol) of lithium chloride (LiCl) and 190 g of tetrahydrofuran (THF) were placed in a Schlenk tube under an argon (Ar) atmosphere and cooled to −78 ° C.
After dehydrating and degassing the inside of the tube, 0.56 ml (1.00 mol / L hexane / cyclohexane mixed solution, 0.56 mmol) of secondary butyllithium (Sec-BuLi) was added as an anionic polymerization initiator under an Ar atmosphere. Subsequently, 10.2 ml (88.73 mmol) of the following monomer M1 was added, and then stirring was performed at −78 ° C. for 30 minutes.
After stirring, 0.12 ml (0.68 mmol) of diphenylethylene (DPE) was added, and the mixture was stirred at −78 ° C. for 30 minutes. Further, 0.79 ml (3.51 mmol) of the following monomer M2 was added, and the mixture was stirred at 0 ° C. for 180 minutes.
After stirring, 2.28 ml (56.36 mmol) of methanol was added as a polymerization inhibitor at −78 ° C. to terminate the reaction.
The obtained reaction polymerization solution is added dropwise to a large amount of methanol to precipitate a polymer, and the precipitated white powder is washed with a large amount of methanol, washed with a large amount of pure water, and then dried. As a result, 8.34 g (yield 83%) of the target polymer compound (P) -1 was obtained.

For the obtained polymer compound (P) -1, the weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 24100, and the molecular weight dispersion (Mw / Mn) was 1.08.
The carbon 13 as a result of an analysis by nuclear magnetic resonance spectrum (600 MHz - ¹³ C-NMR) (ratio of the respective structural units within the structural formula (molar ratio)) is l / m = 95.5 / 4.5 Met.

[Synthesis of Polymer Compound (P) -2]
0.239 g (5.63 mmol) of lithium chloride (LiCl) and 190 g of tetrahydrofuran (THF) were placed in a Schlenk tube under an argon (Ar) atmosphere and cooled to −78 ° C.
After dehydrating and degassing the inside of the tube, 0.56 ml (1.00 mol / L hexane / cyclohexane mixed solution, 0.56 mmol) of secondary butyllithium (Sec-BuLi) was added as an anionic polymerization initiator under an Ar atmosphere. Subsequently, 10.2 ml (88.91 mmol) of the following monomer M1 was added, and then stirring was performed at −78 ° C. for 30 minutes.
After stirring, 0.12 ml (0.675 mmol) of diphenylethylene (DPE) was added, and the mixture was stirred at −78 ° C. for 30 minutes. Further, 0.79 ml (4.68 mmol) of the following monomer M3 was added, and the mixture was stirred at 0 ° C. for 180 minutes.
After stirring, 2.28 ml (56.2 mmol) of methanol was added as a polymerization inhibitor at −78 ° C. to terminate the reaction.
The obtained reaction polymerization solution is added dropwise to a large amount of methanol to precipitate a polymer, and the precipitated white powder is washed with a large amount of methanol, washed with a large amount of pure water, and then dried. As a result, 8.34 g (yield 83%) of the target polymer compound (P) -2 was obtained.

For the obtained polymer compound (P) -2, the weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 30,000, and the molecular weight dispersion (Mw / Mn) was 1.06.
The carbon 13 as a result of an analysis by nuclear magnetic resonance spectrum (600 MHz - ¹³ C-NMR) (ratio of the respective structural units within the structural formula (molar ratio)) is l / m = 95.5 / 4.5 Met.

Conjugate acid of monomer (mx):
PKa10.13 of the conjugate acid of monomer M2
PKa 8.18 of conjugate acid of monomer M3

<Preparation of polymer composition for thickening resist pattern>
Each component shown in Table 1 was mixed and dissolved to prepare a polymer composition for thickening the resist pattern (hereinafter, also simply referred to as “polymer composition”). Each polymer composition was prepared with a total solid content concentration (total mass excluding solvent) of 1.5% by mass.

Each abbreviation in Table 1 has the following meanings. The value in [] is the blending amount (part by mass).
(X) -1: The above-mentioned polymer compound (P) -1.
(X) -2: The above-mentioned polymer compound (P) -2.

(Y1) -1: Pyridazine represented by the following chemical formula (Y1) -1. Conjugate acid pKa3.12. logP = -0.51.
(Y1) -2: 7-diethylamino-4-methylcoumarin represented by the following chemical formula (Y1) -2. Conjugate acid pKa 3.40. logP = 3.45.
(Y1) -3: 2,6-diisopropylaniline represented by the following chemical formula (Y1) -3. Conjugate acid pKa4.25. logP = 3.05.
(Y1) -4: 2,6-lutidine represented by the following chemical formula (Y1) -4. Conjugate acid pKa 6.70. logP = 1.60.
(Y1) -5: 4-Dimethylaminopyridine represented by the following chemical formula (Y1) -5. Conjugate acid pKa9.20. logP = 1.34.
(Y1) -6: Trimethylamine represented by the following chemical formula (Y1) -6. Conjugate acid pKa9.75. logP = 0.12.
(Y1) -7: 2,6-dihexylpyridine represented by the following chemical formula (Y1) -7. Conjugate acid pKa 6.67. logP = 6.70.

(Y2) -1: Diethylamine represented by the following chemical formula (Y2) -1. Conjugate acid pKa10.76. logP = 0.66.
(Y2) -2: 2- (4-morpholinyl) ethyl ester represented by the following chemical formula (Y2) -2. Conjugate acid pKa6.00. logP = 7.90.
(Y2) -3: Heptane represented by the following chemical formula (Y2) -3.
(Y2) -4: Tarshari butyl methyl ether represented by the following chemical formula (Y2) -4.
(S) -1: Butyl acetate.

<Preparation of resist composition>
Each component shown in Table 2 was mixed and dissolved to prepare a chemically amplified resist composition.

Each abbreviation in Table 2 has the following meanings. The value in [] is the blending amount (part by mass).
(A) -1: A polymer compound represented by the following chemical formula (A) -1. The weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement is 7,000, and the molecular weight dispersion (Mw / Mn) is 1.56. ^{13 The} copolymerization composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by C-NMR is l / m = 50/50.

(B) -1: An acid generator composed of a compound represented by the following chemical formula (B) -1.
(D) -1: An acid diffusion control agent composed of a compound represented by the following chemical formula (D) -1.
(E) -1: Salicylic acid.

(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 10,000, and the molecular weight dispersion (Mw / Mn) is 1.78. ^{13 The} copolymerization composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by C-NMR is l / m = 50/50.

(S) -2: Propylene glycol monomethyl ether acetate.
(S) -3: Propylene glycol monomethyl ether.

<Formation of resist pattern>
A resist pattern in which the resist pre-pattern was thickened was formed by the following series of steps A, B, C and D.

[Step A]
The organic antireflection film composition "ARC-29A" (trade name, manufactured by Brewer Science Co., Ltd.) was applied onto a 12-inch silicon wafer using a spinner, and fired 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, and a support was prepared.
Next, the above-mentioned chemically amplified resist composition is applied onto the organic antireflection film using a spinner, and prebaked (PAB) treatment is performed on a hot plate at a temperature of 110 ° C. for 60 seconds. By drying, a resist film having a film thickness of 100 nm was formed.
Next, an ArF excimer laser (193 nm) was applied to the resist film by an exposure apparatus NSR-S609B (manufactured by Nikon Corporation; NA1.07, Crosspole) to each of the following target (1) and target (2) mask patterns (6). % Halftone) was selectively irradiated.
Target (1): Contact hole (Dense CH) pattern
Pitch 110nm / Round hole diameter 60nm
Target (2): Elliptical hole pattern
Pitch in the X direction 110 nm / hole minor axis 65 nm
Y-direction pitch 330 nm / hole major axis 174 nm
Next, post-exposure heating (PEB) treatment was performed under the conditions of a temperature of 85 ° C. for 60 seconds.
Then, solvent development was carried out for 13 seconds using butyl acetate, and shake-off drying was carried out.
Then, a baking process (post-baking) was performed at a temperature of 100 ° C. for 45 seconds.
As a result, a hole pattern (solvent-developed negative resist pre-pattern with carboxy groups exposed on the surface) was formed as the resist pre-pattern.

[Step B]
Next, the polymer compositions of each example were applied using a spinner on the support on which the resist pre-pattern was formed so as to cover the entire resist pre-pattern, to form a polymer film. The coating film thickness of this polymer film was 60 nm on average.

[Step C]
Next, the resist pre-pattern and the polymer film coating the resist pre-pattern were heated at each temperature (shrink bake temperature) shown in Table 3 for 60 seconds.

[Step D]
Next, solvent development was carried out for 13 seconds using butyl acetate.
As a result, a fine hole pattern in which the resist pre-pattern was thickened and the hole diameter was reduced was formed.

<Evaluation of the width of the thickened part (shrink volume: SV)>
For each hole pattern formed above, the width of the thickened portion (shrink) corresponding to “T _0a + T _0b (= T _{1 −} T ₂ = T ₀ )” in FIG. 1 (d) by the following method. Volume (nm)) was evaluated.
Each resist pre-pattern and each hole pattern after step D are observed from above the pattern by a length measuring SEM (scanning electron microscope, accelerating voltage 500V, product name: CG5000, manufactured by Hitachi High-Technologies Corporation) and targeted. The hole diameter in the pattern of (1) was measured.

For the perfect circular hole portion and the elliptical hole portion in the hole pattern of each target, “T _0a + T _0b (= T _{1 −} T ₂ = T ₀ )” in FIG. 1 (d) by the following method. The width (shrink volume (nm)) of the thickened portion corresponding to the above was determined.
For the elliptical hole portion, the ratio (Y direction / X direction) of the shrink volume in the X direction, the shrink volume in the Y direction, and the shrink volume in the X direction and the shrink volume in the Y direction was determined.
These results are shown in Table 3.

In Table 3, the resin component (X) is combined with the specific base component (Y) based on the comparison between Examples 1 to 5, 7 to 11 and Comparative Example 1, and the comparison between Example 6 and Comparative Example 2. It can be seen that the shrink volume is increased by applying the present invention. In addition, by applying the present invention, it can be seen that in the elliptical hole pattern, the thickness is sufficiently thickened in both the X direction and the Y direction, miniaturization is achieved, and a resist pattern having a desired shape can be formed.

The polymers of Examples 1 to 11 as compared with the case of using the polymer compositions of Comparative Examples 3 and 4 containing the component (Y) having a pKa larger than the pKa of the conjugate acid of the monomer (mx). The evaluation of shrink volume was superior when the composition was used.

Compared with the case of using the polymer composition of Comparative Example 5 containing the component (Y) having a logP value exceeding 7.5, the case of using the polymer compositions of Examples 1 to 11 has a shrink volume. The evaluation was excellent.

1 ... Support,
2 ... Resist pre-pattern,
3 ... Polymer membrane,
3a ... Developer insoluble layer,
4 ... Resist pattern

Claims (5)

A polymer composition for thickening a resist pattern used for thickening a resist pre-pattern in which acidic groups are exposed on the surface.
It contains a resin component (X) having a thickening function of the resist pre-pattern and a base component (Y).
The resin component (X) has a structural unit derived from a monomer (mx) containing a basic group.
The base component (Y) has a pKa in which the acid dissociation constant (pKa) of the conjugate acid is smaller than the pKa of the conjugate acid of the monomer (mx), and the logP value is 7.5 or less. a compound (Y1) seen including,
The compound (Y1) is a compound represented by the following general formula (Y1-1), a compound represented by the following general formula (Y1-3), 7-diethylamino-4-methylcoumarin, 2,6- A polymer composition for thickening a resist pattern, which is one or more compounds selected from the group consisting of diisopropylaniline, 4-dimethylaminopyridine, and trimethylamine .

[In the formula (Y1-1), R ^y1 represents an alkyl group having 1 to 5 carbon atoms. n _y1 is an integer from 0 to 2. In the formula (Y1-3), R ^y5 and R ^y6 each independently represent an alkyl group having 1 to 12 carbon atoms. ] The polymer composition for thickening a resist pattern according to claim 1, wherein the compound (Y1) has a pKa of a conjugate acid of 2 to 10. The polymer composition for thickening a resist pattern according to claim 1 or 2, wherein the compound (Y1) has a molecular weight of less than 1000. The resist pattern thickness according to any one of claims 1 to 3, wherein the content of the compound (Y1) is more than 0 parts by mass and 300 parts by mass or less with respect to 100 parts by mass of the resin component (X). Polymer composition for meating. It is a method of forming a resist pattern in which the resist pre-pattern is thickened.
Step A of forming a resist pre-pattern on the support with exposed acidic groups on the surface,
The polymer composition for thickening the resist pattern according to any one of claims 1 to 4 is applied onto a support on which the resist pre-pattern is formed so as to cover the resist pre-pattern. Step B to form the film and
Step C of forming a developer-insoluble layer on the surface of the resist pre-pattern,
Step D of developing the resist prepattern on which the developer insoluble layer is formed and the polymer film covering the resist prepattern to form a thickened resist prepattern.
A method for forming a resist pattern, which comprises.

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