JP7479142B2 - Resist composition and method for forming resist pattern - Google Patents

Description

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

In recent years, advances in lithography technology have led to rapid progress in miniaturization of patterns in the manufacture of semiconductor elements and liquid crystal display elements. A common method of miniaturization is to shorten the wavelength (increase the energy) of the exposure light source.

Resist materials are required to have lithography properties such as sensitivity to these exposure light sources and resolution capable of reproducing patterns with fine dimensions.
As a resist material that satisfies such requirements, a chemically amplified resist composition that contains a base component whose solubility in a developer changes due to the action of acid, and an acid generator component that generates acid upon exposure, has been used so far.

Resist materials are required to have lithography properties such as sensitivity to these exposure light sources and resolution capable of reproducing patterns with fine dimensions.
As a resist material that satisfies such requirements, a chemically amplified resist composition that contains a base component whose solubility in a developer changes due to the action of acid, and an acid generator component that generates acid upon exposure, has been used so far.
For example, when the developer is an alkaline developer (alkaline development process), a positive-type chemically amplified resist composition generally contains a resin component (base resin) whose solubility in an alkaline developer increases under the action of an acid, and an acid generator component. When a resist film formed using such a resist composition is selectively exposed during resist pattern formation, an acid is generated from the acid generator component in the exposed area, and the polarity of the base resin increases under the action of the acid, so that the exposed area of the resist film becomes soluble in an alkaline developer. Therefore, a positive pattern is formed in which the unexposed area of the resist film remains as a pattern by alkaline development.

In addition, as a resist material, a chemically amplified resist composition containing a base material component soluble in an alkaline developer (alkali-soluble base material component), an acid generator component that generates an acid by exposure, and a crosslinker component has been used. When an acid is generated from the acid generator component by exposure, the acid acts to crosslink the alkali-soluble base material component and the crosslinker component, resulting in a decrease in solubility in an alkaline developer. Therefore, in forming a resist pattern, when a resist film obtained by applying the chemically amplified resist composition on a support is selectively exposed, the exposed portion of the resist film becomes poorly soluble in an alkaline developer, while the unexposed portion of the resist film remains soluble in an alkaline developer, and thus a negative resist pattern is formed by developing with an alkaline developer.
For example, Patent Document 1 describes a negative chemically amplified resist composition that contains an alkali-soluble polyhydroxystyrene resin, an acid crosslinking substance, a specific photoacid generator, and a dissolution promoter.

Japanese Patent No. 3655030

As a result of the investigations conducted by the present inventors, when a resist pattern was formed using a negative resist composition that employed an alkali-soluble polyhydroxystyrene resin as the base component, wet etching resistance was sometimes insufficient when a thick resist film on the order of microns was formed using the resist composition and etching was performed after forming the resist pattern.

The present invention has been made in consideration of the above circumstances, and aims to provide a resist composition capable of forming a resist pattern with good etching resistance, and a method for forming a resist pattern using the resist composition.

In order to solve the above problems, the present invention employs the following configuration.
That is, a first aspect of the present invention is a negative resist composition that contains a polymeric compound (A1) having a structural unit (a10) represented by general formula (a10-1) below, an acid generator (B0) represented by general formula (b0-1) below, a crosslinking agent (C), and an aromatic compound (Z) that has one or two phenolic hydroxyl groups in the molecule and does not have a carboxy group.

［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^ｘ１は、単結合又は２価の連結基である。Ｗａ^ｘ１は、置換基を有していてもよい芳香族炭化水素基である。ｎ_ａｘ１は、１以上の整数である。］

[In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. Ya ^x1 is a single bond or a divalent linking group. Wa ^x1 is an aromatic hydrocarbon group which may have a substituent. n _ax1 is an integer of 1 or more.]

［式中、Ｒｂ^１は有機基である。Ｒｂ^２は、下記一般式（ｂ０－ｒ－１）又は下記一般式（ｂ０－ｒ－２）で表される基である。］

[In the formula, ^Rb1 is an organic group. ^Rb2 is a group represented by the following general formula (b0-r-1) or the following general formula (b0-r-2)]

［式（ｂ０－ｒ－１）中、Ｒｂ^２０１及びＲｂ^２０２は、それぞれ独立に、有機基である。＊は結合手を示す。式（ｂ０－ｒ－２）中、Ｘｂは、－（Ｏ＝）Ｃ－Ｎ－Ｃ（＝Ｏ）－と共に環状イミド構造を有する環式基を形成する基である。＊は結合手を示す。］

[In formula (b0-r-1), Rb ²⁰¹ and Rb ²⁰² are each independently an organic group. * represents a bond. In formula (b0-r-2), Xb represents a group that forms a cyclic group having a cyclic imide structure together with -(O=)C-N-C(=O)-. * represents a bond.]

The second aspect of the present invention is a method for forming a resist pattern, comprising the steps of forming a resist film on a support using the resist composition according to the first aspect, exposing the resist film, and developing the exposed resist film to form a resist pattern.

According to the present invention, it is possible to provide a resist composition capable of forming a resist pattern having good etching resistance, and a method for forming a resist pattern using the resist composition.

In this specification and claims, the term "aliphatic" is a relative concept to aromaticity and is defined as meaning a group, compound, etc. that does not have aromaticity.
Unless otherwise specified, the term "alkyl group" includes linear, branched and cyclic monovalent saturated hydrocarbon groups. The same applies to the alkyl group in an alkoxy group.
Unless otherwise specified, the term "alkylene group" includes linear, branched and cyclic divalent saturated hydrocarbon groups.
The "halogen atom" includes a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
The term "structural unit" refers to a monomer unit that constitutes a polymeric compound (resin, polymer, copolymer).
The phrase "may have a substituent" includes both the case where a hydrogen atom (--H) is replaced with a monovalent group and the case where a methylene group (--CH ₂ -) is replaced with a divalent group.
The term "exposure" is intended to include any concept including irradiation with radiation.

The term "acid-decomposable group" refers to a group having acid decomposability in which at least a part of the bonds in the structure of the acid-decomposable group can be cleaved by the action of an acid.
Examples of acid-decomposable groups whose polarity increases under the action of an acid include groups that are decomposed by the action of an acid to generate a polar group.
Examples of the polar group include a carboxy group, a hydroxyl group, an amino group, and a sulfo group (-SO ₃ H).
More specific examples of the acid-decomposable group include groups in which the polar group is protected with an acid-dissociable group (for example, a group in which the hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).

The term "acid dissociable group" refers to both (i) a group having acid dissociability in which the bond between the acid dissociable group and an atom adjacent to the acid dissociable group can be cleaved by the action of an acid, and (ii) a group in which a part of the bond is cleaved by the action of an acid and then a decarboxylation reaction occurs, thereby cleaving the bond between the acid dissociable group and an atom adjacent to the acid dissociable group.
The acid dissociable group constituting the acid decomposable group must be a group with lower polarity than the polar group generated by dissociation of the acid dissociable group, and thus, when the acid dissociable group is dissociated by the action of acid, a polar group with higher polarity than the acid dissociable group is generated, and the polarity increases.As a result, the polarity of the entire (A1) component increases.By increasing the polarity, the solubility in the developer changes relatively, and when the developer is an alkaline developer, the solubility increases, and when the developer is an organic developer, the solubility decreases.

The "base material component" is an organic compound that has a film-forming ability. Organic compounds used as base material components are broadly divided into non-polymers and polymers. Non-polymers are generally those with a molecular weight of 500 or more and less than 4000. Hereinafter, the term "low molecular weight compound" refers to a non-polymer with a molecular weight of 500 or more and less than 4000. Polymers are generally those with a molecular weight of 1000 or more. Hereinafter, the terms "resin," "polymer compound," or "polymer" refer to a polymer with a molecular weight of 1000 or more. The molecular weight of the polymer is the weight average molecular weight calculated in terms of polystyrene by GPC (gel permeation chromatography).

The term "derived structural unit" refers to a structural unit formed by cleavage of a multiple bond between carbon atoms, for example, an ethylenic double bond.
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 ^αx ) substituting the hydrogen atom bonded to the carbon atom at the α-position is an atom or group other than a hydrogen atom. It also includes an itaconic acid diester in which the substituent (R ^αx ) is substituted with a substituent containing an ester bond, and an α-hydroxyacrylic ester in which the substituent (R ^αx ) is substituted with a hydroxyalkyl group or a group in which the hydroxyl group is modified. The carbon atom at the α-position of an acrylic acid ester refers to the carbon atom to which the carbonyl group of acrylic acid is bonded, unless otherwise specified.
Hereinafter, an acrylic ester in which the hydrogen atom bonded to the carbon atom at the α-position is substituted with a substituent will sometimes be referred to as an α-substituted acrylic ester.

The term "derivative" refers to a concept that includes compounds in which the hydrogen atom at the α-position of the target compound is replaced with other substituents such as an alkyl group or a halogenated alkyl group, as well as derivatives thereof. Examples of such derivatives include compounds in which the hydrogen atom of the hydroxyl group of a target compound, which may have the hydrogen atom at the α-position replaced with a substituent, is replaced with an organic group; compounds in which the hydrogen atom at the α-position of the target compound, which may have the hydrogen atom at the α-position replaced with a substituent, is bonded to a substituent other than a hydroxyl group, and the like. The α-position refers to the first carbon atom adjacent to the functional group, unless otherwise specified.
Examples of the substituent that substitutes the hydrogen atom at the α-position of the hydroxystyrene include the same as those for R ^αx .

In this specification and claims, some structures represented by chemical formulas may have asymmetric carbons, and enantiomers or diastereomers may exist. In such cases, a single chemical formula represents all of the isomers. These isomers may be used alone or as a mixture.

(Resist Composition)
The resist composition related to the first aspect of the present invention is a negative resist composition.
One embodiment of such a resist composition includes a resist composition containing a base component (A) (hereinafter also referred to as "component (A)") whose solubility in a developer changes due to the action of an acid, an acid generator component (B) (hereinafter also referred to as "component (B)") that generates an acid upon exposure to light, a crosslinker (C) (hereinafter also referred to as "component (C)"), and an aromatic compound (Z) (hereinafter also referred to as "component (Z)") that has one or two phenolic hydroxyl groups in the molecule and does not have a carboxy group.
In the resist composition of this embodiment, the component (A) includes a polymeric compound (A1) (hereafter referred to as "component (A1)") that has a structural unit (a10) represented by general formula (a10-1), and the component (B) includes an acid generator (B0) (hereafter referred to as "component (B0)") represented by general formula (b0-1).

When a resist film is formed using the resist composition of this embodiment and selectively exposed to light, an acid is generated in the exposed areas of the resist film, and the solubility of component (A) in the developer changes due to the action of the acid, whereas the solubility of component (A) in the developer does not change in the unexposed areas of the resist film, resulting in a difference in solubility in the developer between the exposed and unexposed areas of the resist film. Therefore, when the resist film is developed with an alkali, the unexposed areas of the resist film are dissolved and removed, forming a negative resist pattern.

In this specification, a resist composition in which an exposed portion of a resist film is dissolved and removed to form a positive resist pattern is referred to as a positive resist composition, and a resist composition in which an unexposed portion of a resist film is dissolved and removed to form a negative resist pattern is referred to as a negative resist composition. The resist composition of this embodiment is a negative resist composition.

<Component (A)>
The component (A) is a base component whose solubility in a developer changes due to the action of an acid.
In the present invention, the "base component" refers to an organic compound having a film-forming ability, and preferably an organic compound having a molecular weight of at least 500 is used. When the molecular weight of the organic compound is at least 500, the film-forming ability is improved, and in addition, a nano-level resist pattern can be easily formed.
The organic compounds used as the base component are broadly divided into non-polymers and polymers.
The non-polymer used is usually one having a molecular weight of 500 or more and less than 4000. Hereinafter, the term "low molecular weight compound" refers to a non-polymer having a molecular weight of 500 or more and less than 4000.
The polymer to be used usually has a molecular weight of 1000 or more. Hereinafter, when the term "resin", "polymeric compound" or "polymer" is used, it refers to a polymer having a molecular weight of 1000 or more.
The molecular weight of the polymer is determined by gel permeation chromatography (GPC) and converted into polystyrene equivalent weight average molecular weight.

In the resist composition of this embodiment, the component (A) contains at least a polymeric compound (A1) that has a structural unit (a10) represented by general formula (a0-1), and may also contain in combination a polymeric compound and/or a low molecular weight compound other than the component (A1).
When a resist film is formed using a resist composition containing at least the component (A1), and the resist film is selectively exposed, for example, when the resist composition contains the component (B), an acid is generated from the component (B) in the exposed portion of the resist film, and crosslinking occurs between the components (A1) via the structural unit (a10) having crosslinking properties due to the action of the acid, and as a result, the solubility of the exposed portion of the resist film in an alkaline developer is reduced. Therefore, when a resist film obtained by applying the resist composition of this embodiment to a support is selectively exposed in the formation of a resist pattern, the exposed portion of the resist film becomes poorly soluble in an alkaline developer, while the unexposed portion of the resist film remains soluble in an alkaline developer, and thus a negative resist pattern is formed by developing with an alkaline developer.

Regarding the Component (A1): The component (A1) is a polymeric compound that has a structural unit (a10) represented by general formula (a0-1).
The component (A1) is preferably a copolymer that, in addition to the structural unit (a10), further contains a structural unit (a11) that contains an aromatic ring (excluding an aromatic ring having a hydroxy group bonded thereto) in its side chain.
Furthermore, the component (A1) may also contain structural units other than the structural units (a10) and (a11).

Regarding the structural unit (a10):
The structural unit (a10) is a structural unit represented by general formula (a10-1) shown below.

［式中、Ｒは、水素原子、炭素数１～５のアルキル基又は炭素数１～５のハロゲン化アルキル基である。Ｙａ^ｘ１は、単結合又は２価の連結基である。Ｗａ^ｘ１は、置換基を有していてもよい芳香族炭化水素基である。ｎ_ａｘ１は、１以上の整数である。］
［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^ｘ１は、単結合又は２価の連結基である。Ｗａ^ｘ１は、置換基を有してもよい芳香族炭化水素基である。ｎ_ａｘ１は、１以上の整数である。］

[In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. Ya ^x1 is a single bond or a divalent linking group. Wa ^x1 is an aromatic hydrocarbon group which may have a substituent. n _ax1 is an integer of 1 or more.]
[In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. Ya ^x1 is a single bond or a divalent linking group. Wa ^x1 is an aromatic hydrocarbon group which may have a substituent. n _ax1 is an integer of 1 or more.]

In the above formula (a10-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.
The alkyl group having 1 to 5 carbon atoms for R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof 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.
The halogenated alkyl group having 1 to 5 carbon atoms represented by R is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms have been substituted with halogen atoms. As the halogen atom, a fluorine atom is particularly preferred.
R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and from the viewpoint of industrial availability, is more preferably a hydrogen atom, a methyl group, or a trifluoromethyl group, is further preferably a hydrogen atom or a methyl group, and is particularly preferably a methyl group.

In the above formula (a10-1), Ya ^x1 represents a single bond or a divalent linking group.
In the above chemical formula, the divalent linking group for Ya ^x1 is not particularly limited, but suitable examples include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

Optionally substituted divalent hydrocarbon group:
When Ya ^x1 is a divalent hydrocarbon group which may have a substituent, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

Aliphatic Hydrocarbon Group in Ya ^x1 The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.
Examples of the aliphatic hydrocarbon group include linear or branched aliphatic hydrocarbon groups, and aliphatic hydrocarbon groups containing a ring in the structure.

...Straight-chain or branched-chain aliphatic hydrocarbon group The straight-chain aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, even more preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms.
As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferable, and specific examples thereof include a methylene group [-CH ₂ -], an ethylene group [-(CH ₂ ) ₂ -], a trimethylene group [-(CH ₂ ) ₃ -], a tetramethylene group [-(CH ₂ ) ₄ -], a pentamethylene group [-(CH ₂ ) ₅ -], etc.
The branched aliphatic hydrocarbon group preferably has 2 to 10 carbon atoms, more preferably has 3 to 6 carbon atoms, even more preferably has 3 or 4 carbon atoms, and most preferably has 3 carbon atoms.
The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof _include alkylmethylene groups such as -CH( _CH3 )-, -CH( _CH2CH3 )-, -C( _CH3 ) _{2- , -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3 ) 2- ; alkylethylene groups such as -CH ( CH3 ) CH2- ,} -CH( _CH3 )CH( _CH3 ) _- , -C( _CH3 ) _{2CH2- ,} -CH _{( CH2CH3} ) _{CH2- ,} and -C( _CH2CH3 ) _{2 - CH2- ;} and alkyl alkylene groups such as alkyl trimethylene groups such as _-CH (CH ₃ )CH ₂ CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ CH ₂ -, etc. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

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 and substituted with a fluorine atom, and a carbonyl group.

... Aliphatic hydrocarbon groups containing a ring in the structure Examples of the aliphatic hydrocarbon groups containing a ring in the structure include cyclic aliphatic hydrocarbon groups (groups in which two hydrogen atoms have been removed from an aliphatic hydrocarbon ring) which may contain a substituent containing a heteroatom in the ring structure, groups in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, groups in which the cyclic aliphatic hydrocarbon group is interposed in the middle of a linear or branched aliphatic hydrocarbon group, etc. Examples of the linear or branched aliphatic hydrocarbon group include the same as those described above.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms have been removed from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

The cyclic aliphatic hydrocarbon group may or may not have a substituent, which may include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, etc.
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.
The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and further preferably a methoxy group or an ethoxy group.
The halogen atom as the substituent is preferably a fluorine atom.
Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group are substituted with the halogen atoms.
In the cyclic aliphatic hydrocarbon group, some of the carbon atoms constituting the ring structure may be substituted with a substituent containing a hetero atom. Preferred examples of the substituent containing a hetero atom include -O-, -C(=O)-O-, -S-, -S(=O) ₂ - and -S(=O) ₂ -O-.

Aromatic Hydrocarbon Group in Ya ^x1 The aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring.
The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The number of carbon atoms in the aromatic ring is preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and particularly preferably 6 to 12. However, the number of carbon atoms does not include the number of carbon atoms in the substituent.
Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which a part of the carbon atoms constituting the aromatic hydrocarbon ring is replaced with a heteroatom. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.
Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms have been removed from the aromatic hydrocarbon ring or aromatic heterocycle (arylene group or heteroarylene group); a group in which two hydrogen atoms have been removed from an aromatic compound containing two or more aromatic rings (e.g., biphenyl, fluorene, etc.); a group in which one hydrogen atom of a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or heteroaryl group) has been substituted with an alkylene group (e.g., a group in which one hydrogen atom has been further removed from the aryl group in an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group). The number of carbon atoms in the alkylene group bonded to the aryl group or heteroaryl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

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

Divalent linking groups containing heteroatoms:
When Ya ^x1 is a divalent linking group containing a hetero atom, preferred examples of the linking group include -O-, -C(=O)-O-, -O-C(=O)-, -C(=O)-, -O-C(=O)-O-, -C(=O)-NH-, -NH-, -NH-C(=NH)- (H may be substituted by a substituent such as an alkyl group or an acyl group), -S-, -S(=O) ₂ -, -S(=O) ₂ -O-, general 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 -, -Y ^{21 -O} -C(=O)-Y ²² - or a group represented by -Y ²¹ -S(═O) ₂ -O-Y ²² - [wherein Y ²¹ and Y ²² each independently represent a divalent hydrocarbon group which may have a substituent, O is an oxygen atom, and m″ is an integer of 0 to 3].
When the divalent linking group containing a hetero atom is -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, or -NH-C(=NH)-, the H may be substituted with a substituent such as an alkyl group, acyl, etc. 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.
In the general 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 -, -Y ²¹ -O-C(═O)-Y ²² - or -Y ²¹ -S(═O) ₂ -O-Y ²² -, Y ²¹ and Y ²² each independently represent a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include the same as those (divalent hydrocarbon groups which may have a substituent) listed in the description of the divalent linking group for Ya ^x1 above.
Y ²¹ is preferably a linear aliphatic hydrocarbon group, more preferably a linear alkylene group, still more preferably a linear alkylene group having 1 to 5 carbon atoms, and particularly preferably a methylene group or ethylene group.
Y ²² is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group or an alkylmethylene group. 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.
In the group represented by the formula -[Y ²¹ -C(═O)-O] _m" -Y ²² -, m" is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and particularly preferably 1. That is, as the group represented by the formula -[Y ²¹ -C(═O)-O] _m" -Y ²² -, a group represented by the formula -Y ²¹ -C(═O)-O-Y ²² - is particularly preferred. Of these, a group represented by the formula -(CH ₂ ) _a' -C(═O)-O-(CH ₂ ) _b' - is 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, even more preferably 1 or 2, and most preferably 1. b' is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, even more preferably 1 or 2, and most preferably 1.

Among the above, Ya ^x1 is preferably a single bond, an ester bond [-C(=O)-O-, -O-C(=O)-], an ether bond (-O-), a linear or branched alkylene group, or a combination thereof, and more preferably a single bond or an ester bond [-C(=O)-O-, -O-C(=O)-].

In the above formula (a10-1), Wa ^x1 represents an aromatic hydrocarbon group which may have a substituent.
The aromatic hydrocarbon group in Wa ^x1 may be a group in which (n _ax1 +1) hydrogen atoms have been removed from an aromatic ring which may have a substituent. The aromatic ring here is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, even more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which a part of the carbon atoms constituting the aromatic hydrocarbon ring is substituted with a heteroatom. Examples of heteroatoms in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.
Further, examples of the aromatic hydrocarbon group in Wa ^x1 include groups in which (n _ax1 +1) hydrogen atoms have been removed from an aromatic compound containing an aromatic ring which may have two or more substituents (e.g., biphenyl, fluorene, etc.).
Among the above, Wa ^x1 is preferably a group in which (n _ax1 +1) hydrogen atoms have been removed from benzene, naphthalene, anthracene or biphenyl, more preferably a group in which (n _ax1 +1) hydrogen atoms have been removed from benzene or naphthalene, and even more preferably a group in which (n _ax1 +1) hydrogen atoms have been removed from benzene.

The aromatic hydrocarbon group in Wa ^x1 may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, and a halogenated alkyl group. Examples of the alkyl group, alkoxy group, halogen atom, and halogenated alkyl group as the substituent include the same as those exemplified as the substituent of the cyclic aliphatic hydrocarbon group in Ya ^x1 . The substituent is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, more preferably a linear or branched alkyl group having 1 to 3 carbon atoms, further preferably an ethyl group or a methyl group, and particularly preferably a methyl group. It is preferable that the aromatic hydrocarbon group in Wa ^x1 does not have a substituent.

In the formula (a10-1), n _ax1 is an integer of 1 or more, preferably an integer of 1 to 10, more preferably an integer of 1 to 5, still more preferably 1, 2 or 3, and particularly preferably 1 or 2.

Specific examples of the structural unit (a10) represented by the aforementioned formula (a10-1) are shown below.
In each of the following formulas, R ^α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

The structural unit (a10) contained in the component (A1) may be of one type, or may be of two or more types.
The proportion of the structural unit (a10) in the component (A1) is preferably 70 to 99 mol %, more preferably 75 to 99 mol %, even more preferably 80 to 99 mol %, and particularly preferably 85 to 95 mol %, based on the total (100 mol %) of all structural units constituting the component (A1).
By ensuring that the proportion of the structural unit (a10) is at least as large as the lower limit of the above range, development properties and lithography properties can be further improved, while by ensuring that the proportion is at most the upper limit of the above range, it becomes easier to achieve a balance with other structural units.

Regarding the structural unit (a11):
The component (A1) is preferably a copolymer that, in addition to the aforementioned structural unit (a10), further has a structural unit (a11) derived from a compound that contains an aromatic ring (excluding an aromatic ring having a hydroxy group bonded thereto) in its side chain.
Suitable examples of the compound having an aromatic ring (excluding an aromatic ring having a hydroxy group bonded thereto) in the side chain include compounds represented by general formula (a11-1) shown below.

［式（ａ１１－１）中、Ｒａ^ｘ２は重合性基含有基である。Ｗａ^ｘ２は、（ｎ_ａｘ２＋１）価の芳香族炭化水素基である。但し、Ｒａ^ｘ２とＷａ^ｘ２とで縮合環構造が形成されていてもよい。Ｒａ^ｘ０２は、Ｗａ^ｘ２（芳香族炭化水素基）を構成する水素原子を置換する置換基である。ｎ_ａｘ２は、０～３の整数である。ｎ_ａｘ２が２以上の場合、複数のＲａ^ｘ０２が相互に結合して環構造を形成してもよい。］

[In formula (a11-1), Ra ^x2 is a polymerizable group-containing group. Wa ^x2 is an aromatic hydrocarbon group having a valence of (n _ax2 +1). However, Ra ^x2 and Wa ^x2 may form a condensed ring structure. Ra ^x02 is a substituent that substitutes a hydrogen atom constituting Wa ^x2 (aromatic hydrocarbon group). n _ax2 is an integer of 0 to 3. When n _ax2 is 2 or more, a plurality of Ra ^x02 may be bonded to each other to form a ring structure.]

In the above formula (a11-1), Ra ^x2 represents a polymerizable group-containing group.
The "polymerizable group" in Ra ^x2 is a group that enables a compound having a polymerizable group to be polymerized by radical polymerization or the like, and refers to a group that contains a multiple bond between carbon atoms, such as an ethylenic double bond.
Examples of the polymerizable group include a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a fluorovinyl group, a difluorovinyl group, a trifluorovinyl group, a difluorotrifluoromethylvinyl group, a trifluoroallyl group, a perfluoroallyl group, a trifluoromethylacryloyl group, a nonylfluorobutylacryloyl group, a vinyl ether group, a fluorine-containing vinyl ether group, an allyl ether group, a fluorine-containing allyl ether group, a styryl group, a vinyl naphthyl group, a fluorine-containing styryl group, a fluorine-containing vinyl naphthyl group, a norbornyl group, a fluorine-containing norbornyl group, and a silyl group.
The polymerizable group-containing group may be a group composed only of a polymerizable group, or may be a group composed of a polymerizable group and a group other than the polymerizable group. Examples of the group other than the polymerizable group include a divalent hydrocarbon group which may have a substituent, and a divalent linking group containing a hetero atom.

Suitable examples of Ra ^x2 include groups represented by the chemical formula CH ₂ ═C(R)-Ya ^x0 -, in which R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and Ya ^x0 is a divalent linking group.

In the formula (a11-1), Wa ^x2 represents an aromatic hydrocarbon group having a valence of (n _ax2 +1), and examples thereof include the same as Wa ^x1 in the formula (a10-1).

However, Ra ^x2 and Wa ^x2 may form a condensed ring structure.
When Ra ^x2 and Wa ^x2 form a fused ring structure, the fused ring structure contains an aromatic ring derived from Wa ^x2 . In addition, the multiple bond between the carbon atoms of the polymerizable group derived from Ra ^x2 is cleaved to form the main chain of the component (A1). That is, a part of the carbon atoms constituting the fused ring constitutes the main chain of the component (A1).

In the above formula (a11-1), Ra ^x02 is a substituent that substitutes a hydrogen atom that constitutes Wa ^x2 (an aromatic hydrocarbon group).
Examples of the substituent in Ra ^x02 include an alkyl group, an alkoxy group, and an acyloxy group.
The alkyl group as the substituent in Ra ^x02 is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group, an ethyl group, a propyl group, an n-butyl group or a tert-butyl group.
The alkoxy group as the substituent in Ra ^x02 is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and particularly preferably a methoxy group or an ethoxy group.
The acyloxy group as the substituent in Ra ^x02 preferably has 2 to 6 carbon atoms, more preferably CH ₃ C(═O)—O— (acetoxy group) or C ₂ H ₅ C(═O)—O—, particularly preferably CH ₃ C(═O)—O— (acetoxy group).

In the above formula (a11-1), n _ax2 represents an integer of 0 to 3, preferably 0, 1 or 2, and more preferably 0 or 1.
When n _ax2 is 2 or more, multiple Ra ^x02 may be bonded to each other to form a ring structure. The ring structure formed here may be a hydrocarbon ring or a heterocyclic ring. For example, there is a ring structure formed by two Ra ^x02 bonded to the same aromatic ring in Wa ^x2 and one side (bond between carbon atoms) of the aromatic ring (Wa ^x2 ) to which the two Ra ^x02 are bonded.

Suitable examples of such structural unit (a11) include structural units represented by the following general formulas (a11-u1-1) to (a11-u1-6):

［式中、Ｒ^αは、水素原子、メチル基又はトリフルオロメチル基である。Ｒ^βは、アルキル基、アルコキシ基又はアシルオキシ基である。ｎ_ａｘ２は、０～３の整数である。ｎ_ａｘ２が２以上の場合、複数のＲ^βが相互に結合して、環構造を形成してもよい。ｎ_２１、ｎ_２２、ｎ_２４及びｎ_２５は、それぞれ独立に、０又は１である。ｎ_２３及びｎ_２６は、それぞれ独立に、１又は２である。］

[In the formula, R ^α is a hydrogen atom, a methyl group, or a trifluoromethyl group. R ^β is an alkyl group, an alkoxy group, or an acyloxy group. n _ax2 is an integer of 0 to 3. When n _ax2 is 2 or more, a plurality of R ^β may be bonded to each other to form a ring structure. n ₂₁ , n ₂₂ , n ₂₄ , and n ₂₅ are each independently 0 or 1. n ₂₃ and n ₂₆ are each independently 1 or 2.]

In the above formulas (a11-u1-1) to (a11-u1-6), the alkyl group, alkoxy group, and acyloxy group for R ^β are the same as the alkyl group, alkoxy group, and acyloxy group exemplified as the substituent for Ra ^x02 in the above formula (a11-1).

Specific examples of the structural unit (structural unit (a11)) derived from the compound represented by general formula (a11-1) are shown below.
In each of the following formulas, R ^α represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

Among the above examples, the structural unit (a11) is preferably at least one type selected from the group consisting of structural units represented by general formulas (a11-u1-1) to (a11-u1-3), and the structural unit represented by general formula (a11-u1-1) is more preferable.
Of these, the structural unit (a11) is preferably a structural unit represented by any one of chemical formulas (a11-u1-11), (a11-u1-21) and (a11-u1-31).

The structural unit (a11) contained in the component (A1) may be of one type, or may be of two or more types.
When the component (A1) contains the structural unit (a11), the proportion of the structural unit (a11) in the component (A1) is preferably 1 to 30 mol %, more preferably 1 to 25 mol %, even more preferably 1 to 20 mol %, and particularly preferably 5 to 15 mol %, based on the combined total (100 mol %) of all structural units constituting the component (A1).
By ensuring that the proportion of the structural unit (a11) is at least as large as the lower limit of the above range, etching resistance and lithography properties can be further improved, while by ensuring that the proportion is at most the upper limit of the above range, it becomes easier to achieve a balance with other structural units.

Other structural units
The component (A1) may include other structural units in addition to the structural units (a10) and (a11).
Examples of compounds that derive such other structural units include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; methacrylic acid derivatives having a carboxy group and an ester bond such as 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl maleic acid, 2-methacryloyloxyethyl phthalic acid, and 2-methacryloyloxyethyl hexahydrophthalic acid; (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate. (meth)acrylic acid hydroxyalkyl esters such as hydroxypropyl (meth)acrylate; (meth)acrylic acid aryl esters such as phenyl (meth)acrylate and benzyl (meth)acrylate; dicarboxylic acid diesters such as diethyl maleate and dibutyl fumarate; vinyl group-containing aliphatic compounds such as vinyl acetate; conjugated diolefins such as butadiene and isoprene; nitrile group-containing polymerizable compounds such as acrylonitrile and methacrylonitrile; chlorine-containing polymerizable compounds such as vinyl chloride and vinylidene chloride; amide bond-containing polymerizable compounds such as acrylamide and methacrylamide; and epoxy group-containing polymerizable compounds.

In the resist composition of this embodiment, the component (A) contains a polymeric compound (A1) (component (A1)) that has the structural unit (a10).
Preferred examples of the component (A1) include polymeric compounds having at least the structural unit (a10). Specifically, suitable examples include polymeric compounds having a repeating structure of the structural unit (a10) (homopolymers composed of the structural unit (a10)); and polymeric compounds having a repeating structure of the structural unit (a10) and the structural unit (a11).

The weight average molecular weight (Mw) of the component (A1) (based on polystyrene equivalent by gel permeation chromatography (GPC)) is not particularly limited, but is preferably 500 to 50,000, more preferably 1,000 to 30,000, and even more preferably 2,000 to 20,000.
When the Mw of the component (A1) is less than or equal to the preferred upper limit of this range, the compound has sufficient solubility in a resist solvent for use as a resist, and when it is more than or equal to the preferred lower limit of this range, the dry etching resistance and cross-sectional shape of the resist pattern are improved.

The dispersity (Mw/Mn) of the (A1) component is not particularly limited, but is preferably 1.0 to 4.0, more preferably 1.0 to 3.0, and particularly preferably 1.5 to 2.5. Mn indicates the number average molecular weight.

The component (A1) can be produced by dissolving monomers from which each structural unit is derived in a polymerization solvent, and then adding a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate (e.g., V-601), and polymerizing the resulting mixture.
Alternatively, the component (A1) can be produced by dissolving a monomer that derives the structural unit (a10) and, if necessary, a monomer that derives a structural unit other than the structural unit (a10) in a polymerization solvent, adding the above-mentioned radical polymerization initiator to the resulting solution to polymerize, and then carrying out a deprotection reaction.
During polymerization, a chain transfer agent such as HS-CH ₂ -CH ₂ -CH ₂ -C(CF ₃ ) ₂ -OH may be used in combination to introduce a -C(CF ₃ ) ₂ -OH group to the end. A copolymer having a hydroxyalkyl group in which some of the hydrogen atoms of the alkyl group are substituted with fluorine atoms in this way is effective in reducing development defects and LER (line edge roughness: non-uniform unevenness of the line sidewalls).

Regarding the Component (A2) The resist composition of this embodiment may use, as the component (A), a base component (A2) (hereafter referred to as the component (A2)) that does not fall under the category of the component (A1) above and whose solubility in a developer changes under the action of an acid.
There are no particular restrictions on the component (A2), and any of the many compounds conventionally known as base components for chemically amplified resist compositions can be used.
The component (A2) may be a polymeric compound or a low molecular weight compound, and may be a combination of two or more of these.

The proportion of component (A1) in component (A) is preferably 25% by mass or more, more preferably 50% by mass or more, and even more preferably 75% by mass or more, and may be 100% by mass, based on the total mass of component (A). When the proportion is 25% by mass or more, a resist pattern that is excellent in various lithography properties such as high sensitivity, resolution, and improved roughness is easily formed.

In the resist composition of this embodiment, the content of component (A) may be adjusted according to the thickness of the resist film to be formed, etc.

<Component (B)>
Regarding the Component (B0), the component (B) is an acid generator component that generates acid upon exposure. In the resist composition of this embodiment, the component (B) includes at least an acid generator (B0) (component (B0)) represented by the following general formula (b0-1):

［式中、Ｒｂ^１は有機基である。Ｒｂ^２は、下記一般式（ｂ０－ｒ－１）又は下記一般式（ｂ０－ｒ－２）で表される基である。］

[In the formula, ^Rb1 is an organic group. ^Rb2 is a group represented by the following general formula (b0-r-1) or the following general formula (b0-r-2)]

［式（ｂ０－ｒ－１）中、Ｒｂ^２０１及びＲｂ^２０２は、それぞれ独立に、有機基である。＊は結合手を示す。式（ｂ０－ｒ－２）中、Ｘｂは、－（Ｏ＝）Ｃ－Ｎ－Ｃ（＝Ｏ）－と共に環状イミド構造を有する環式基を形成する基である。＊は結合手を示す。］

[In formula (b0-r-1), Rb ²⁰¹ and Rb ²⁰² are each independently an organic group. * represents a bond. In formula (b0-r-2), Xb represents a group that forms a cyclic group having a cyclic imide structure together with -(O=)C-N-C(=O)-. * represents a bond.]

In this embodiment, the component (B0) is not particularly limited as long as it is a compound represented by the formula (b0-1), and examples thereof include at least one compound selected from the group consisting of the following general formulae (b0-1-1) to (b0-1-6).

［式中、Ｒｂ^１１及びＲｂ^２１は、それぞれ独立に、非芳香族性基である。］

[In the formula, ^Rb11 and ^Rb21 each independently represent a non-aromatic group.]

［式中、Ｒｂ^１２は、アルキル基又はハロゲン化アルキル基である。Ｒｂ^２２は、芳香族性基である。］

[In the formula, Rb ¹² is an alkyl group or a halogenated alkyl group. Rb ²² is an aromatic group.]

［式中、Ｒｂ^１３は置換を有してもよい炭化水素基である。ｎｂ３は、２又は３である。Ａｂは２価又は３価の有機基である。］

[In the formula, ^Rb13 is a hydrocarbon group which may have a substituent. nb3 is 2 or 3. Ab is a divalent or trivalent organic group.]

［式中、Ｒｂ^１４は、芳香族性多環式炭化水素基、飽和若しくは不飽和の非芳香族性多環式炭化水素基又はそれらの置換誘導体の基である。Ｒｂ^２４は、不活性有機基である。］

[In the formula, Rb ¹⁴ is an aromatic polycyclic hydrocarbon group, a saturated or unsaturated non-aromatic polycyclic hydrocarbon group, or a substituted derivative thereof. Rb ²⁴ is an inert organic group.]

［式中、Ｒｂ^１５は、置換若しくは未置換の一価の飽和炭化水素基、不飽和炭化水素基又は芳香族性基である。Ｘｂ^５は、－（Ｏ＝）Ｃ－Ｎ－Ｃ（＝Ｏ）－と共に環状イミド構造を有する環式基を形成する基である。］

[In the formula, Rb ¹⁵ is a substituted or unsubstituted monovalent saturated hydrocarbon group, unsaturated hydrocarbon group, or aromatic group. Xb ⁵ is a group that forms a cyclic group having a cyclic imide structure together with -(O=)C-N-C(=O)-.]

［式中、Ｒｂ^１６は、置換基を有してもよいアルキル基又は置換基を有してもよい芳香族炭化水素基である。Ｒｂ^２６１～Ｒｂ^２６３は、それぞれ独立に、ハロゲン原子、炭素数１～６のアルキル基又は炭素数１～６のアルコキシ基である。ｎｂ６は、０～５の整数である。］

[In the formula, Rb ¹⁶ is an alkyl group which may have a substituent or an aromatic hydrocarbon group which may have a substituent. Rb ²⁶¹ to Rb ²⁶³ are each independently a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. nb6 is an integer of 0 to 5.]

In the above formula (b0-1-1), examples of the non-aromatic group for Rb ¹¹ and Rb ¹² include an alkyl group, a halogenoalkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an alkoxy group, a cycloalkoxy group, and an adamantyl group.

The alkyl group in Rb ¹¹ and Rb ¹² is preferably a linear or branched alkyl group having 1 to 12 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-octyl group, or an n-dodecyl group.
The halogenoalkyl group in ^Rb11 and ^Rb12 is not particularly limited in the number of halogen atoms, and one or more may be introduced. The halogen atom may be any of a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The halogenoalkyl group is preferably a halogenoalkyl group having 1 to 4 carbon atoms, such as a chloromethyl group, a trichloromethyl group, a trifluoromethyl group, and a 2-bromopropyl group.
The alkenyl group in Rb ¹¹ and Rb ¹² is preferably a straight-chain or branched-chain alkenyl group having 2 to 6 carbon atoms, such as a vinyl group, a 1-propenyl group, an isopropenyl group, or a 2-butenyl group.
The cycloalkyl group in ^Rb11 and ^Rb12 is preferably a cycloalkyl group having 5 to 12 carbon atoms, such as a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, or a cyclododecyl group. The cycloalkenyl group is preferably a cycloalkenyl group having 4 to 8 carbon atoms, such as a 1-cyclobutenyl group, a 1-cyclopentenyl group, a 1-cyclohexenyl group, a 1-cycloheptenyl group, or a 1-cyclooctenyl group.
The alkoxy group in Rb ¹¹ and Rb ¹² is preferably an alkoxy group having 1 to 8 carbon atoms, such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, or a pentoxy group.
The cycloalkoxy group for Rb ¹¹ and Rb ¹² is preferably a cycloalkoxy group having 5 to 8 carbon atoms, such as a cyclopentoxy group, a cyclohexyloxy group, or the like.

In the formula (b0-1-1), ^Rb11 is preferably an alkyl group, a halogenoalkyl group, or a cycloalkyl group, particularly preferably an alkyl group. ^Rb21 is preferably an alkyl group, a cycloalkyl group, or a cycloalkenyl group, particularly preferably a cycloalkenyl group. Of these, it is more preferable that ^Rb11 is an alkyl group having 1 to 4 carbon atoms, and ^Rb21 is a cyclopentenyl group.

Specific examples of the compound represented by the formula (b0-1-1) include α-(methylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(methylsulfonyloxyimino)-1-cyclohexenylacetonitrile, α-(methylsulfonyloxyimino)-1-cycloheptenylacetonitrile, α-(methylsulfonyloxyimino)-1-cyclooctenylacetonitrile, α-(trifluoromethylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(trifluoromethylsulfonyloxyimino)-cyclohexylacetonitrile, α-(ethylsulfonyloxyimino)-ethylacetonitrile, α-(propylsulfonyloxyimino)-propylacetonitrile, α-(cyclohexylsulfonyloxyimino)-ethylacetonitrile, imino)-cyclopentylacetonitrile, α-(cyclohexylsulfonyloxyimino)-cyclohexylacetonitrile, α-(cyclohexylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(ethylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(isopropylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(n-butylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(ethylsulfonyloxyimino)-1-cyclohexenylacetonitrile, α-(isopropylsulfonyloxyimino)-1-cyclohexenylacetonitrile, α-(n-butylsulfonyloxyimino)-1-cyclohexenylacetonitrile, and the like.

In the formula (b0-1-2), examples of the alkyl group for ^Rb12 include linear or branched alkyl groups having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group.
Examples of the halogenated alkyl group for Rb ¹² include halogenated alkyl groups having 1 to 4 carbon atoms, such as a chloromethyl group, a trichloromethyl group, a trifluoromethyl group, and a 2-bromopropyl group.

In the formula (b0-1-2), the aromatic group in Rb ²² means a group exhibiting physical and chemical properties specific to aromatic compounds, such as a phenyl group, a naphthyl group, a furyl group, and a thienyl group. The aromatic group in Rb ²² may have some of the hydrogen atoms in the aromatic ring constituting the aromatic group substituted with a substituent. Examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, and a nitro group.

Specific examples of the compound represented by the formula (b0-1-2) include α-(methylsulfonyloxyimino)-phenylacetonitrile, α-(methylsulfonyloxyimino)-4-methoxyphenylacetonitrile, α-(methylsulfonyloxyimino)-4-methylphenylacetonitrile, α-(trifluoromethylsulfonyloxyimino)-phenylacetonitrile, α-(trifluoromethylsulfonyloxyimino)-4-methoxyphenylacetonitrile, α-(ethylsulfonyloxyimino)-4-methoxyphenylacetonitrile, α-(propylsulfonyloxyimino)-4-methylphenylacetonitrile, and α-(methylsulfonyloxyimino)-4-bromophenylacetonitrile.

In the formula (b0-1-3), examples of the hydrocarbon group in Rb ¹³ include aromatic and non-aromatic hydrocarbon groups. The aromatic group preferably has 6 to 14 carbon atoms, and examples thereof include aromatic hydrocarbon groups such as phenyl, tolyl, methoxyphenyl, xylyl, biphenyl, naphthyl, and anthryl groups, and heterocyclic groups such as furanyl, pyridyl, and quinolyl groups. Non-aromatic hydrocarbon groups include hydrocarbon groups that do not have a ring that exhibits aromaticity, such as a benzene ring, a naphthalene ring, a furan ring, a thiophene ring, or a pyridine ring, such as an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, such as an alkyl group, an alkenyl group, a cycloalkyl group, or a cycloalkenyl group. The alkyl group or alkenyl group may be either linear or branched, and is preferably one having 1 to 12 carbon atoms, and the cycloalkyl group or cycloalkenyl group is preferably one having 4 to 12 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-octyl group, an n-dodecyl group, and the like; examples of the alkenyl group include an ethenyl group, a propenyl group, a butenyl group, a butadienyl group, a hexenyl group, an octadienyl group, and the like; examples of the cycloalkyl group include a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and a cyclododecyl group; and examples of the cycloalkenyl group include a 1-cyclobutenyl group, a 1-cyclopentenyl group, a 1-cyclohexenyl group, a 1-cycloheptenyl group, and a 1-cyclooctenyl group.

In the above formula (b0-1-3), the hydrocarbon group for ^Rb13 may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an alkoxy group, and an acyl group.

In the formula (b0-1-3), examples of the divalent or trivalent organic group in Ab include divalent or trivalent aliphatic hydrocarbon groups and aromatic hydrocarbon groups.

Specific examples of the compound represented by formula (b0-1-3) are shown below.

In the formula (b0-1-4), examples of the aromatic polycyclic hydrocarbon group for Rb ¹⁴ include aromatic condensed polycyclic hydrocarbon groups such as a 2-indenyl group, a 1-naphthyl group, a 2-naphthyl group, and a 2-anthryl group, and aromatic non-condensed polycyclic hydrocarbon groups such as a biphenyl group, a terphenyl group, etc. In addition, examples of substituted derivative groups thereof include those in which the aromatic ring of these groups is substituted with a substituent such as a halogen atom such as a chlorine atom, a bromine atom, or an iodine atom, a nitro group, an amino group, a hydroxyl group, an alkyl group, or an alkoxyl group, such as a 5-hydroxy-1-naphthyl group or a 4-amino-1-naphthyl group.

In the formula (b0-1-4), examples of the saturated or unsaturated non-aromatic polycyclic hydrocarbon group in Rb ¹⁴ include polycyclic terpene residues and adamantyl groups, with polycyclic terpene residues being preferred. Examples of the substituted derivative groups include those having appropriate substituents on the ring, such as halogen atoms such as chlorine atoms, bromine atoms, and iodine atoms, nitro groups, amino groups, hydroxyl groups, oxo groups, alkyl groups, and alkoxyl groups. Examples of such groups include camphor-3-yl groups, camphor-8-yl groups, camphor-10-yl groups, and 3-bromocamphor-10-yl groups.
As this Rb ¹⁴ , a naphthyl group and a camphor-10-yl group are preferable, and a 1-naphthyl group is particularly preferable because it has excellent resolution.

In the formula (b0-1-4), the inactive organic group in Rb ²⁴ is an organic group that is inactive to coexisting components under the conditions of use, and is not particularly limited, but is preferably an aromatic group in terms of sensitivity to excimer lasers, electron beams, and X-rays. Examples of the aromatic group include a phenyl group, a naphthyl group, a furyl group, and a thienyl group. These aromatic groups may also have an inactive substituent such as a halogen atom such as a chlorine atom, a bromine atom, or an iodine atom, an alkyl group, an alkoxyl group, or a nitro group.

Specific examples of the compound represented by the formula (b0-1-4) include α-(1-naphthylsulfonyloxyimino)-4-methoxybenzyl cyanide, α-(2-naphthylsulfonyloxyimino)-4-methoxybenzyl cyanide, α-(1-naphthylsulfonyloxyimino)benzyl cyanide, α-(2-naphthylsulfonyloxyimino)benzyl cyanide, α-(10-camphorsulfonyloxyimino)-4-methoxybenzyl cyanide, α-(10-camphorsulfonyloxyimino)benzyl cyanide, α-(3-camphorsulfonyloxyimino)-4-methoxybenzyl cyanide, and α-(3-bromo-10-camphorsulfonyloxyimino)-4-methoxybenzyl cyanide.

In the formula (b0-1-5), examples of the substituted or unsubstituted monovalent saturated or unsaturated hydrocarbon group in Rb ¹⁵ include linear or branched saturated or unsaturated hydrocarbon groups having 1 to 8 carbon atoms and groups in which these are substituted with halogen atoms, nitro groups, acetylamino groups, lower alkoxy groups, monocyclic aryl groups, etc., with those having a substituent such as a halogen atom or a lower alkoxy group being particularly preferred. Also, examples of the substituted or unsubstituted monovalent aromatic group in Rb ¹⁵ include monocyclic or bicyclic groups, with those having a benzene ring substituted with a vinyl group, alkyl group, alkoxy group, halogen atom, etc. being particularly preferred.

In the above formula (b0-1-5), examples of the cyclic group having a cyclic imide structure formed by ^Xb5 together with -(O=)C-N-C(=O)- include a succinimide ring, a maleimide ring, a glutarimide ring, a phthalimide ring, and a 1,8-naphthalenedicarboxyimide ring.
The cyclic group having a cyclic imide structure formed by ^Xb5 together with -(O=)C-N-C(=O)- may have a substituent. Examples of the substituent include a halogen atom, a nitro group, an acetylamino group, an alkoxy group, and a monocyclic aryl group.

Specific examples of the compound represented by the formula (b0-1-5) include N-methylsulfonyloxysuccinimide, N-isopropylsulfonyloxysuccinimide, N-chloroethylsulfonyloxysuccinimide, N-(p-methoxyphenyl)sulfonyloxysuccinimide, N-(p-vinylphenyl)sulfonyloxysuccinimide, N-naphthylsulfonyloxysuccinimide, N-phenylsulfonyloxysuccinimide, N-(2,4,6-trimethylphenyl)sulfonyloxysuccinimide, N-methylsulfonyloxymaleimide, N-isopropylsulfonyloxymaleimide, N-chloroethylsulfonyloxymaleimide, N-(p-methoxyphenyl)sulfonyloxymaleimide, N-(p-vinylphenyl)sulfonyloxysuccinimide, ) sulfonyloxymaleimide, N-naphthylsulfonyloxymaleimide, N-phenylsulfonyloxymaleimide, N-(2,4,6-trimethylphenyl)sulfonyloxymaleimide, N-methylsulfonyloxyphthalimide, N-isopropylsulfonyloxyphthalimide, N-chloroethylsulfonyloxyphthalimide, N-(p-methoxyphenyl)sulfonyloxyphthalimide, N-(p-vinylphenyl)sulfonyloxyphthalimide, N-naphthylsulfonyloxyphthalimide, N-phenylsulfonyloxyphthalimide, N-(2,4,6-trimethylphenyl)sulfonyloxyphthalimide, and the compounds described in paragraphs [0089] to [0091] of JP-A-10-097075.

In the formula (b0-1-6), the alkyl group for Rb ¹⁶ is preferably a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, a 2,4,4-trimethylpentyl group, a 2-ethylhexyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and a cyclododecyl group.
Among these, the alkyl group for Rb ¹⁶ is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 5 carbon atoms.

The alkyl group in Rb ¹⁶ may have a substituent. Examples of the substituent include a halogen atom, a halogenated alkyl group, CN, NO ₂ , a phenyl group, an alkoxy group, a carboxy group, a carbonyl group, a sulfonyl group, and an amino group.

In the above formula (b0-1-6), examples of the aromatic hydrocarbon group for Rb ¹⁶ include a phenyl group, a naphthyl group, a phenanthryl group, an anthracyl group, and a heteroaryl group.
The aromatic hydrocarbon group in Rb ¹⁶ may have a substituent. Examples of the substituent include a halogen atom, a halogenated alkyl group, CN, NO ₂ , a phenyl group, an alkoxy group, a carboxy group, a carbonyl group, a sulfonyl group, and an amino group.

Specific examples of the compound represented by the formula (b0-1-6) include the compound represented by the following chemical formula (b0-1-61) and the compounds of Examples 25 to 40 and 53 in JP-T-2002-508774.

Other specific examples of component (B0) include the compounds described in paragraphs [0056], [0058], [0060], and [0063] of Japanese Patent No. 4,110,392, and the compounds described in paragraphs [0053], [0054], [0056], [0058], and [0060]-[0062] of Japanese Patent No. 4,000,469.

Among them, the component (B1) is preferably at least one selected from the group consisting of the compound represented by the formula (b0-1-2), the compound represented by the formula (b0-1-3), the compound represented by the formula (b0-1-5), and the compound represented by the formula (b0-1-6), and more preferably at least one selected from the group consisting of the compound represented by the formula (b0-1-2), the compound represented by the formula (b0-1-3), and the compound represented by the formula (b0-1-6).

Specific preferred examples of component (B0) are given below.

The resist composition of this embodiment may contain one type of component (B0) alone or two or more types in combination.

In the resist composition of this embodiment, the content of the component (B0) relative to 100 parts by mass of the component (A) is preferably 50 parts by mass or less, more preferably 0.1 to 40 parts by mass, even more preferably 0.1 to 30 parts by mass, and particularly preferably 0.1 to 20 parts by mass.
By setting the content of the component (B) within the above range, sufficient pattern formation can be achieved.

Component (B1) The resist composition of this embodiment may include, as the component (B), an acid generator other than the component (B0) (hereafter referred to as “component (B1)”).
There are no particular limitations on the component (B1), and any of the compounds that have been proposed as acid generators for chemically amplified resist compositions can be used.
Examples of such acid generators include onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators, diazomethane-based acid generators such as bisalkyl- or bisarylsulfonyl diazomethanes and poly(bissulfonyl) diazomethanes, nitrobenzylsulfonate-based acid generators, and disulfone-based acid generators.

Examples of onium salt acid generators include a compound represented by the following general formula (b-1) (hereinafter also referred to as "component (b-1)"), a compound represented by general formula (b-2) (hereinafter also referred to as "component (b-2)"), or a compound represented by general formula (b-3) (hereinafter also referred to as "component (b-3)").

［式中、Ｒ^１０１、Ｒ^１０４～Ｒ^１０８はそれぞれ独立に、置換基を有してもよい環式基、置換基を有してもよい鎖状のアルキル基、又は置換基を有し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^１０２はフッ素原子又は炭素数１～５のフッ素化アルキル基である。Ｙ^１０１は単結合、又は酸素原子を含む２価の連結基である。Ｖ^１０１～Ｖ^１０３はそれぞれ独立に単結合、アルキレン基又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又は酸素原子である。Ｌ^１０３～Ｌ^１０５はそれぞれ独立に単結合、－ＣＯ－又は－ＳＯ_２－である。ｍは１以上の整数であって、Ｍ’^ｍ＋はｍ価のオニウムカチオンである。］

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

{anion portion}
Anion Moiety of Component (b-1) In formula (b-1), R ¹⁰¹ is a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent.

Optionally substituted cyclic group:
The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

The aromatic hydrocarbon group in R ¹⁰¹ is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, still more preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and most preferably 6 to 10 carbon atoms. However, this carbon number does not include the number of carbon atoms in the substituent.
Specific examples of the aromatic ring contained in the aromatic hydrocarbon group in R ¹⁰¹ include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, and aromatic heterocycles in which a part of the carbon atoms constituting these aromatic rings are substituted with heteroatoms, etc. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom.
Specific examples of the aromatic hydrocarbon group for R ¹⁰¹ include a group in which one hydrogen atom has been removed from the aromatic ring (aryl group: for example, a phenyl group, a naphthyl group, etc.), a group in which one hydrogen atom of the aromatic ring has been substituted with an alkylene group (for example, an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, a 2-naphthylethyl group, etc.), etc. The alkylene group (the 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.

The cyclic aliphatic hydrocarbon group for R ¹⁰¹ includes an aliphatic hydrocarbon group containing a ring in the structure.
Examples of the aliphatic hydrocarbon group that contains a ring in its structure include alicyclic hydrocarbon groups (groups in which one hydrogen atom has been removed from an aliphatic hydrocarbon ring), groups in which an alicyclic hydrocarbon group is bonded to the end of a straight-chain or branched-chain aliphatic hydrocarbon group, and groups in which an alicyclic hydrocarbon group is present in the middle of a straight-chain or branched-chain aliphatic hydrocarbon group.
The alicyclic hydrocarbon group preferably has 3 to 30 carbon atoms, and more preferably has 3 to 20 carbon atoms.
The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include 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 preferably has 7 to 30 carbon atoms. Among them, the polycycloalkane is more preferably a polycycloalkane having a polycyclic skeleton of a bridged ring system such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane; or a polycycloalkane having a polycyclic skeleton of a condensed ring system such as a cyclic group having a steroid skeleton.

Among these, the cyclic aliphatic hydrocarbon group for R ¹⁰¹ is preferably a group in which one or more hydrogen atoms have been removed from a monocycloalkane or a polycycloalkane, more preferably a group in which one hydrogen atom has been removed from a polycycloalkane, particularly preferably an adamantyl group, a norbornyl group, or a cyclic group having a steroid skeleton, and most preferably an adamantyl group or a cyclic group having a steroid skeleton.

The linear or branched aliphatic hydrocarbon group which may be bonded to the alicyclic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms.
As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferable, and specific examples thereof include a methylene group [-CH ₂ -], an ethylene group [-(CH ₂ ) ₂ -], a trimethylene group [-(CH ₂ ) ₃ -], a tetramethylene group [-(CH ₂ ) ₄ -], a pentamethylene group [-(CH ₂ ) ₅ -], etc.
The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specific examples thereof _include alkylmethylene groups such as -CH( _CH3 )-, -CH( _CH2CH3 )-, -C( _CH3 ) _{2- , -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3 ) 2- ; alkylethylene groups such as -CH ( CH3 ) CH2- ,} -CH( _CH3 )CH( _CH3 ) _- , -C( _CH3 ) _{2CH2- ,} -CH _{( CH2CH3} ) _{CH2- ,} and -C( _CH2CH3 ) _{2 - CH2- ;} and alkyl alkylene groups such as alkyl trimethylene groups such as _-CH (CH ₃ )CH ₂ CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ CH ₂ -, etc. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

The cyclic hydrocarbon group in R ¹⁰¹ may contain a heteroatom, such as a heterocycle. Specific examples include the lactone-containing cyclic groups represented by the general formulae (a2-r-1) to (a2-r-7) above, the —SO ₂ —-containing cyclic groups represented by the general formulae (a5-r-1) to (a5-r-4) above, and the heterocyclic groups represented by the following chemical formulae (r-hr-1) to (r-hr-16).

Examples of the substituent in the cyclic group of R ¹⁰¹ include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, and a nitro group.
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group or a tert-butyl group.
The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and most preferably a methoxy group or an ethoxy group.
Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, with a fluorine atom being preferred.
Examples of the halogenated alkyl group as a substituent include alkyl groups having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, n-butyl, and tert-butyl groups, in which some or all of the hydrogen atoms have been substituted with the above-mentioned halogen atoms.
The carbonyl group as a substituent is a group that substitutes a methylene group (-CH ₂ -) that constitutes a cyclic hydrocarbon group.

A chain alkyl group which may have a substituent:
The chain alkyl group for R ¹⁰¹ may be either a straight chain or a branched chain.
The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably has 1 to 15 carbon atoms, and most preferably has 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decanyl group, an undecyl group, a dodecyl group, a tridecyl group, an isotridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, an isohexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a henicosyl group, and a docosyl group.
The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably has 3 to 15 carbon atoms, and most preferably has 3 to 10 carbon atoms. Specific examples include a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

A chain alkenyl group which may have a substituent:
The chain alkenyl group for R ¹⁰¹ may be either linear or branched, and preferably has 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms, further preferably 2 to 4 carbon atoms, and particularly preferably 3 carbon atoms. Examples of linear alkenyl groups include vinyl groups, propenyl groups (allyl groups), and butynyl groups. Examples of branched alkenyl groups include 1-methylvinyl groups, 2-methylvinyl groups, 1-methylpropenyl groups, and 2-methylpropenyl groups.
Of the above chain alkenyl groups, linear alkenyl groups are preferred, vinyl groups and propenyl groups are more preferred, and vinyl groups are particularly preferred.

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

Among these, 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, preferred are a phenyl group, a naphthyl group, a group in which one or more hydrogen atoms have been removed from a polycycloalkane, a lactone-containing cyclic group represented by each of the general formulae (a2-r-1), (a2-r-3) to (a2-r-7), and an —SO ₂ —-containing cyclic group represented by each of the general formulae (a5-r-1) to (a5-r-4).

In the formula (b-1), Y ¹⁰¹ is a single bond or a divalent linking group containing an oxygen atom.
When Y ¹⁰¹ is a divalent linking group containing an oxygen atom, Y ¹⁰¹ may contain an atom other than an oxygen atom. Examples of the atom other than an oxygen atom include a carbon atom, a hydrogen atom, a sulfur atom, and a nitrogen atom.
Examples of such a divalent linking group containing an oxygen atom include the linking groups represented by the above general formulae (y-al-1) to (y-al-8).
Y ¹⁰¹ is preferably a divalent linking group containing an ester bond or a divalent linking group containing an ether bond, and more preferably a linking group represented by each of the above general formulae (y-al-1) to (y-al-5).

In the formula (b-1), V ¹⁰¹ is a single bond, an alkylene group, or a fluorinated alkylene group. The alkylene group or fluorinated alkylene group in V ¹⁰¹ preferably has 1 to 4 carbon atoms. The fluorinated alkylene group in V ¹⁰¹ may be a group in which some or all of the hydrogen atoms in the alkylene group in V ¹⁰¹ have been substituted with fluorine atoms. In particular, V ¹⁰¹ is preferably a single bond, or a fluorinated alkylene group having 1 to 4 carbon atoms.

In the 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 moiety of the component (b-1) include, for example, when Y ¹⁰¹ is a single bond, fluorinated alkylsulfonate anions such as trifluoromethanesulfonate anion and perfluorobutanesulfonate anion; and when Y ¹⁰¹ is a divalent linking group containing an oxygen atom, anions represented by any of the following formulas (an-1) to (an-3) are included.

［式中、Ｒ”^１０１は、置換基を有してもよい脂肪族環式基、上記の化学式（ｒ－ｈｒ－１）～（ｒ－ｈｒ－６）でそれぞれ表される１価の複素環式基、又は置換基を有してもよい鎖状のアルキル基である。Ｒ”^１０２は、置換基を有してもよい脂肪族環式基、前記一般式（ａ２－ｒ－１）、（ａ２－ｒ－３）～（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－含有環式基である。Ｒ”^１０３は、置換基を有してもよい芳香族環式基、置換基を有してもよい脂肪族環式基、又は置換基を有してもよい鎖状のアルケニル基である。Ｖ”^１０１は、単結合、炭素数１～４のアルキレン基、又は炭素数１～４のフッ素化アルキレン基である。Ｒ^１０２は、フッ素原子又は炭素数１～５のフッ素化アルキル基である。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 monovalent heterocyclic group represented by each of the above chemical formulas (r-hr-1) to (r-hr-6), or a chain alkyl group which may have a substituent. R" ¹⁰² is an aliphatic cyclic group which may have a substituent, a lactone-containing cyclic group represented by each of the above general formulas (a2-r-1), (a2-r-3) to (a2-r-7), or an -SO ₂ - containing cyclic group represented by each of the above general formulas (a5-r-1) to (a5-r-4). 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 single bond, an alkylene group having 1 to 4 carbon atoms, or a fluorinated alkylene group having 1 to 4 carbon atoms. R ¹⁰² is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. Each v" is independently an integer of 0 to 3, each q" is independently an integer of 1 to 20, and n" is 0 or 1.

The aliphatic cyclic groups which may have a substituent of R″ ¹⁰¹ , R″ ¹⁰² and R″ ¹⁰³ are preferably the groups exemplified as the cyclic aliphatic hydrocarbon group of R ^101. Examples of the substituent include the same as the substituents which may substitute the cyclic aliphatic hydrocarbon group of R ¹⁰¹ .

The aromatic cyclic group in R″ ¹⁰³ which may have a substituent is preferably a group exemplified as the aromatic hydrocarbon group in the cyclic hydrocarbon group in ^R101 . Examples of the substituent include the same as the substituent which may substitute the aromatic hydrocarbon group in ^R101 .

The chain alkyl group which may have a substituent in R″ ¹⁰¹ is preferably a group exemplified as the chain alkyl group in ^R101 . The chain alkenyl group which may have a substituent in R″ ¹⁰⁴ is preferably a group exemplified as the chain alkenyl group in ^R101 .

V" ¹⁰¹ is preferably a single bond or a fluorinated alkylene group, more preferably a single bond or a fluorinated alkylene group having 1 to 3 carbon atoms. When V" ¹⁰¹ is a fluorinated alkylene group, V" ¹⁰¹ in -V" ¹⁰¹ -C(F)(R" ¹⁰² )-SO ₃ ^- is preferably -CF ₂ -, -CHF-, -CF ₂ CF ₂ -, -CHFCF ₂ -, -CF(CF ₃ )CF ₂ - or -CH(CF ₃ )CF ₂ -, and more preferably -CF ₂ - or -CHF-.

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.

v" is an integer from 0 to 3, preferably 0 or 1. q" is an integer from 1 to 20, preferably an integer from 1 to 10, more preferably an integer from 1 to 5, even more preferably 1, 2 or 3, and particularly preferably 1 or 2. n" is 0 or 1.

Anion Moiety of Component (b-2) In formula (b-2), R ¹⁰⁴ and R ¹⁰⁵ each independently represent a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a chain-like alkenyl group which may have a substituent, and examples of these include the same as R ¹⁰¹ in formula (b-1). However, R ¹⁰⁴ and R ¹⁰⁵ may be bonded to each other to form a ring.
R ¹⁰⁴ and R ¹⁰⁵ are preferably a chain alkyl group which may have a substituent, and more preferably a linear or branched alkyl group, or a linear or branched fluorinated alkyl group.
The number of carbon atoms in the chain-like alkyl group is preferably 1 to 10, more preferably 1 to 7, and even more preferably 1 to 3. The number of carbon atoms in the chain-like alkyl group of R ¹⁰⁴ and R ¹⁰⁵ is preferably as small as possible within the above-mentioned range of carbon numbers, for reasons such as good solubility in a resist solvent. In addition, in the chain-like alkyl group of R ¹⁰⁴ and R ¹⁰⁵ , the more hydrogen atoms substituted with fluorine atoms, the stronger the acid strength, and therefore the more preferable it is. The ratio of fluorine atoms in the chain-like alkyl group, i.e., the fluorination rate, is preferably 70 to 100%, more preferably 90 to 100%, and most preferably a perfluoroalkyl group in which all hydrogen atoms are substituted with fluorine atoms.
In formula (b-2), V ¹⁰² and V ¹⁰³ each independently represent a single bond, an alkylene group, or a fluorinated alkylene group, and examples of V ¹⁰¹ in formula (b-1) include the same as those described above.
In formula (b-2), L ¹⁰¹ and L ¹⁰² each independently represent a single bond or an oxygen atom.

Anion Moiety of Component (b-3) In formula (b-3), ^R to ^R each independently represent a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a chain-like alkenyl group which may have a substituent, and examples of these include the same as R ¹⁰¹ in formula (b-1).
L ¹⁰³ to L ¹⁰⁵ each independently represent a single bond, —CO— or —SO ₂ —.

{Cation part}
In formulas (b-1), (b-2), and (b-3), m is an integer of 1 or more, and ^M'm+ is an m-valent onium cation, preferably a sulfonium cation or an iodonium cation, and examples thereof include the organic cations represented by the above general formulas (ca-1) to (ca-4), respectively.

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

[In the formula, R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² each independently represent an aryl group which may have a substituent, an alkyl group which may have a substituent, or an alkenyl group which may have a substituent. R ²⁰¹ to R ²⁰³ , R ²⁰⁶ to R ²⁰⁷ , and R ²¹¹ to R ²¹² may each 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, or may each be bonded to each other to form a ring together with the sulfur atom in the formula. R ²¹⁰ is an aryl group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or an -SO ₂ - containing cyclic group which may have a substituent. L ²⁰¹ represents -C(=O)- or -C(=O)-O-. Each of the multiple Y ²⁰¹ independently represents an arylene group, an alkylene group, or an alkenylene group. x is 1 or 2. W ²⁰¹ represents a linking group having a valency of (x+1).

The aryl group in R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² includes an aryl group having 6 to 20 carbon atoms, and a phenyl group or naphthyl group is preferable.
The alkyl group for R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms.
The alkenyl group for R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² preferably has 2 to 10 carbon atoms.
Examples of the substituent that R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² may have include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and groups represented by the following general formulas (ca-r-1) to (ca-r-7), respectively.

［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、置換基を有していてもよい鎖状のアルキル基、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る。］

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

Examples of the optionally substituted cyclic group, optionally substituted chain alkyl group, or optionally substituted chain alkenyl group for ^R'201 include those similar to those for ^R101 in formula (b-1) described below, and examples of the optionally substituted cyclic group or optionally substituted chain alkyl group also include those similar to the acid dissociable group represented by formula (a1-r-2) above.

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, they may be bonded via a heteroatom such as a sulfur atom, an oxygen atom or a nitrogen atom, or a functional group such as a carbonyl group, -SO-, -SO ₂ -, -SO ₃ -, -COO-, -CONH- or -N(R _N )- (wherein R _N is an alkyl group having 1 to 5 carbon atoms). As for the ring formed, one ring containing the sulfur atom in the ring skeleton in the formula is preferably a 3- to 10-membered ring including the sulfur atom, and particularly preferably a 5- to 7-membered ring. Specific examples of the ring formed include 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 phenoxathiin ring, a tetrahydrothiophenium 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 represent an alkyl group, they may be mutually bonded to form a ring.

R ²¹⁰ is an aryl group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, or an --SO ₂ -- containing cyclic group which may have a substituent.
The aryl group for R ²¹⁰ includes unsubstituted aryl groups having 6 to 20 carbon atoms, and is preferably a phenyl group or a naphthyl group.
The alkyl group for R ²¹⁰ is preferably a chain or cyclic alkyl group having 1 to 30 carbon atoms.
The alkenyl group for R ²¹⁰ preferably has a carbon number of 2 to 10. The optionally substituted -SO ₂ -containing cyclic group for R ²¹⁰ is preferably a "-SO ₂ -containing polycyclic group", more preferably a group represented by the above general formula (a5-r-1).

Each Y ²⁰¹ independently represents an arylene group, an alkylene group, or an alkenylene group.
Examples of the arylene group for Y ²⁰¹ include groups in which one hydrogen atom has been removed from the aryl groups exemplified as the aromatic hydrocarbon group for R ¹⁰¹ in formula (b-1) described below.
Examples of the alkylene group and alkenylene group for Y ²⁰¹ include groups in which one hydrogen atom has been removed from the groups exemplified as the chain alkyl group and chain alkenyl group for R ¹⁰¹ in formula (b-1) described below.

In the above formula (ca-4), x is 1 or 2.
W ²⁰¹ is a (x+1)-valent linking group, that is, a divalent or trivalent linking group.
The divalent linking group in W ²⁰¹ is preferably a divalent hydrocarbon group which may have a substituent, and examples thereof include the same divalent hydrocarbon group which may have a substituent as Ya ²¹ in the above general formula (a2-1). The divalent linking group in W ²⁰¹ may be linear, branched, or cyclic, and is preferably cyclic. Among these, a group in which two carbonyl groups are combined at both ends of an arylene group is preferred. Examples of the arylene group include a phenylene group and a naphthylene group, and a phenylene group is particularly preferred.
Examples of the trivalent linking group in W ²⁰¹ include a group in which one hydrogen atom has been removed from the divalent linking group in W ²⁰¹ , a group in which the divalent linking group is further bonded to the divalent linking group, etc. 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 chemical formulas (ca-1-1) to (ca-1-78) and (ca-1-101) to (ca-1-149), respectively.
In the following chemical formula, g1 represents the number of repetitions and is an integer from 1 to 5. g2 represents the number of repetitions and is an integer from 0 to 20. g3 represents the number of repetitions and is an integer from 0 to 20.

［式中、Ｒ”^２０１は水素原子又は置換基である。該置換基としては、上記Ｒ^２０１～Ｒ^２０７およびＲ^２１１～Ｒ^２１２が有してもよい置換基として挙げた、アルキル基、ハロゲン原子、ハロゲン化アルキル基、カルボニル基、シアノ基、アミノ基、アリール基、一般式（ｃａ－ｒ－１）～（ｃａ－ｒ－７）でそれぞれ表される基が挙げられる。］

[In the formula, R" ²⁰¹ is a hydrogen atom or a substituent. Examples of the substituent include an ^{alkyl group} , a halogen atom, a halogenated alkyl group, a carbonyl group, a ^cyano group, an amino group, an aryl group, and groups represented by general formulae (ca-r-1) to (ca-r- ⁷ ), which are listed as the substituents that R 201 to R 207 and R 211 to R 212 may have.]

Specific examples of suitable cations represented by the formula (ca-2) include the cations represented by the following formulas (ca-2-1) to (ca-2-3), the diphenyliodonium cation, and the bis(4-tert-butylphenyl)iodonium cation.

Specific examples of suitable cations represented by the formula (ca-3) include the cations represented by the following formulas (ca-3-1) to (ca-3-7).

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

Among the above, the cation portion ((M ^m+ ) _1/m ) is preferably a cation represented by general formula (ca-1) or (ca-2), and more preferably a cation represented by chemical formulas (ca-1-1) to (ca-1-78), (ca-1-101) to (ca-1-149), and (ca-2-1) to (ca-2-3).

In the resist composition of this embodiment, the component (B1) may use either a single type, or a combination of two or more types.
When the resist composition contains the component (B1), the amount of the component (B1) in the resist composition is preferably 50 parts by mass or less, more preferably 0.1 to 40 parts by mass, even more preferably 0.1 to 30 parts by mass, and particularly preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of the component (A).

<Component (C)>
The component (C) is a crosslinking agent. The component (C) is not particularly limited, and can be arbitrarily selected from those known as crosslinking agents for negative resist compositions. Examples of such acid crosslinking substances include amino resins having hydroxyl groups or alkoxyl groups, such as melamine resins, urea resins, guanamine resins, acetoguanamine resins, benzoguanamine resins, glycoluril-formaldehyde resins, succinylamide-formaldehyde resins, and ethyleneurea-formaldehyde resins. These can be easily obtained by reacting melamine, urea, guanamine, acetoguanamine, benzoguanamine, glycoluril, succinylamide, or ethyleneurea with formalin in boiling water to methylolate, or by further reacting this with a lower alcohol to alkoxylate. In practice, these can be obtained as melamine resins such as Nikalac MX-750, Nikalac MW-30, and Nikalac MW100LM, and urea resins such as Nikalac MX-290 (all manufactured by Sanwa Chemical Co., Ltd.). Benzoguanamine resins such as Cymel 1123 and Cymel 1128 (manufactured by Mitsui Cyanad Co., Ltd.) are also commercially available.
In addition, as the component (C), benzene compounds having an alkoxyl group, such as 1,3,5-tris(methoxymethoxy)benzene, 1,2,4-tris(isopropoxymethoxy)benzene, and 1,4-bis(sec-butoxymethoxy)benzene, and phenol compounds having a hydroxyl group or an alkoxyl group, such as 2,6-dihydroxymethyl-p-tert-butylphenol, can also be used.

Among these, as the component (C), those having an -NCH ₂ -OCH ₃ group are preferable, the compound represented by the following formula (c1-1) or (c1-2) is more preferable, and the compound having a melamine skeleton represented by the following formula (c1-1) or (c1-2) is even more preferable.

［式中、ｎｃ１及びｎｃ２は、それぞれ独立に、１～３の整数である。］

[In the formula, nc1 and nc2 each independently represent an integer of 1 to 3.]

The component (C) may be used alone or in combination of two or more types.
In the resist composition of this embodiment, the amount of the component (C) relative to 100 parts by mass of the component (A) is preferably 1 to 50 parts by mass, more preferably 3 to 40 parts by mass, even more preferably 3 to 30 parts by mass, and most preferably 5 to 25 parts by mass.
When the content of the (C) component is equal to or greater than the lower limit, crosslinking proceeds sufficiently, and the resolution performance and lithography properties are further improved. In addition, a good resist pattern with little swelling can be obtained. When the content of the (C) component is equal to or less than the upper limit, the storage stability of the resist composition is good, and deterioration of sensitivity over time can be easily suppressed.

<Component (Z)>
There are no particular limitations on the component (Z) so long as it is an aromatic compound that has one or two phenolic hydroxyl groups in the molecule and no carboxyl group.
The component (Z) preferably contains at least one selected from the group consisting of compounds represented by the following general formula (z1-1) and compounds represented by the following general formula (z2-1).

［式（ｚ１－１）中、Ｖ_ｚ ^１はヒドロキシ基及びカルボキシ基を有さない２価の連結基である。式（ｚ２－１）中、Ｒｚ^２は、炭化水素基である。ｎ１は１又は２である。ｎ２は２～５の整数である。ただし、ｎ１＋ｎ２≦６である。］

[In formula (z1-1), V _z ¹ is a divalent linking group having neither a hydroxy group nor a carboxy group. In formula (z2-1), Rz ² is a hydrocarbon group. n1 is 1 or 2. n2 is an integer from 2 to 5, with the proviso that n1+n2≦6.]

In the formula (z1-1), examples of the divalent linking group having no hydroxy group or carboxy group in V _z ¹ include the divalent linking groups having no hydroxy group or carboxy group in Ya ^x1 in the above general formula (a10-1). Examples of the divalent linking group in V _z ¹ also include groups in which some of the hydrogen atoms constituting the linear or branched aliphatic hydrocarbon group as the divalent linking group in Ya ^x1 in the above general formula (a10-1) are substituted with aromatic hydrocarbon groups.

Examples of the straight-chain or branched-chain aliphatic hydrocarbon group in the "group in which some of the hydrogen atoms constituting a straight-chain or branched-chain aliphatic hydrocarbon group have been substituted with an aromatic hydrocarbon group" include alkylmethylene groups such as a methylene group [-CH ₂ -], an ethylene group [-(CH ₂ ) ₂ -], -CH(CH ₃ )-, -CH(CH ₂ CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CH ₃ )(CH _{2 CH 3} )-, -C(CH _{3 )} (CH ₂ CH 2 CH ₃ )- and -C(CH ₂ CH 3 ) ₂ -.
Examples of the aromatic hydrocarbon group in the "group in which some of the hydrogen atoms constituting a linear or branched aliphatic hydrocarbon group are substituted with an aromatic hydrocarbon group" include groups in which one hydrogen atom has been removed from an aromatic ring such as benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, etc.
The aromatic hydrocarbon group in the "group in which some of the hydrogen atoms constituting a linear or branched aliphatic hydrocarbon group are substituted with an aromatic hydrocarbon group" may have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an arylalkyl group.
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.
Examples of the alkoxy group, halogen atom and halogenated alkyl group as the substituent include those exemplified as the substituent substituting a hydrogen atom in the cyclic aliphatic hydrocarbon group in the divalent linking group for Ya ^x1 in general formula (a10-1) above.
Examples of the arylalkyl group as the substituent include a benzyl group, a phenethyl group, a phenyl-t-butyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, a 2-naphthylethyl group, etc. The arylalkyl group may have a substituent such as an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an arylalkyl group, etc.

As the compound represented by the formula (z1-1), a compound represented by the following general formula (z1-1-1) is preferred.

［式中、Ｒ_ｚ ^１１及びＲ_ｚ ^１２は、それぞれ独立して、水素原子又は置換基を有してもよい炭化水素基である。Ｒ_ｚ ^１１及びＲ_ｚ ^１２は、相互に結合して環を形成してもよい。］

[In the formula, R _z ¹¹ and R _z ¹² each independently represent a hydrogen atom or a hydrocarbon group which may have a substituent. R _z ¹¹ and R _z ¹² may be bonded to each other to form a ring.]

In the above formula (z1-1-1), examples of the hydrocarbon group for R _z ¹¹ and R _z ¹² include a linear or branched alkyl group and an aromatic hydrocarbon group which may have a substituent.
The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 or 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Among these, a methyl group, an ethyl group, or an n-butyl group is preferable, and a methyl group or an ethyl group is more preferable.
The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably has 3 to 5 carbon atoms. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group, and a 2,2-dimethylbutyl group, and is preferably an isopropyl group.

Examples of the aromatic hydrocarbon group in R _z ¹¹ and R _z ¹² include groups in which one hydrogen atom has been removed from an aromatic ring such as benzene, fluorene, naphthalene, anthracene, phenanthrene, and biphenyl.
The aromatic hydrocarbon group in R _z ¹¹ and R _z ¹² may have a substituent. The substituent is the same as the substituent that may be possessed by the aromatic hydrocarbon group in the "group in which a part of the hydrogen atoms constituting a linear or branched aliphatic hydrocarbon group are substituted with an aromatic hydrocarbon group".

In the formula (z1-1-1), R _z ¹¹ and R _z ¹² may be bonded to each other to form a ring. Examples of the ring formed include an aliphatic ring such as a cyclopentane ring, a cyclohexane ring, or a cycloheptane ring.

In the formula (z1-1-1), R _z ¹¹ and R _z ¹² are preferably a linear alkyl group having 1 to 5 carbon atoms or an aromatic hydrocarbon group which may have a substituent, or R _z ¹¹ and R _z ¹² are bonded to each other to form an aliphatic ring, more preferably a methyl group, a phenyl group, or a 4-(4-hydroxyphenyl-t-butyl)phenyl group, or R _z ¹¹ and R _z ¹² are bonded to each other to form a cyclohexane ring.

In the formula (z2-1), examples of the hydrocarbon group for Rz ² include those exemplified as the hydrocarbon groups for R _z ¹¹ and R _z ¹² in the formula (z1-1-1). Among them, Rz ² is preferably an aromatic hydrocarbon group, more preferably a phenyl group or a benzyl group, and even more preferably a phenyl group.

In the above formula (z 2 - 1 ), n1 is preferably 1. n2 is preferably 2 or 3, and more preferably 2.

The compound represented by the formula (z 2 -1 ) is preferably a compound represented by the following general formula (z1-2-1):

［式中、Ｒｚ^２１及びＲｚ^２２は、それぞれ独立に、芳香族炭化水素基である。］

[In the formula, Rz ²¹ and Rz ²² each independently represent an aromatic hydrocarbon group.]

In the formula (z1-2-1), examples of the hydrocarbon group for Rz ² include those exemplified as the hydrocarbon groups for R _z ¹¹ and R _z ¹² in the formula (z1-1-1). Of these, Rz ² is preferably a phenyl group or a benzyl group, and more preferably a phenyl group.

Specific examples of component (Z) are given below.

The mass average molecular weight (Mw) of the component (Z) is preferably 1,000 or less, more preferably 100 to 950, and even more preferably 150 to 900.
When the mass average molecular weight of the component (Z) is no greater than the upper limit of the above preferred range, substrate adhesion is likely to be improved, and wet etching resistance is likely to be improved.

The component (Z) contained in the resist composition of this embodiment may use either a single type, or a combination of two or more types.
In the resist composition of this embodiment, the content of the component (Z) relative to 100 parts by mass of the component (A) is preferably 0.5 to 30 parts by mass, more preferably 1 to 25 parts by mass, and even more preferably 3 to 20 parts by mass.
When the proportion of the component (Z) is within the above-mentioned preferred range, the etching resistance is good and a pattern with a good shape can be easily formed.

<Optional ingredients>
<Component (D)>
The resist composition in this embodiment may further contain an acid diffusion controller component (hereafter referred to as "component (D)") in addition to components (A), (B), (C) and (Z). The component (D) acts as a quencher (acid diffusion controller) that traps acid generated in the resist composition upon exposure.
Examples of the component (D) include a nitrogen-containing organic compound (D1) (hereinafter referred to as “component (D1)” and a photodecomposable base (D2) (hereinafter referred to as “component (D2)”) which does not fall under the category of component (D1) and which decomposes upon exposure to light and loses its acid diffusion controllability.
By using a resist composition that contains the component (D), the contrast between exposed and unexposed areas of the resist film can be further improved when forming a resist pattern.

Component (D1) The component (D1) is a base component, and is a nitrogen-containing organic compound component that acts as an acid diffusion controller in the resist composition.

The component (D1) is not particularly limited as long as it acts as an acid diffusion control agent, and examples thereof include aliphatic amines and aromatic amines.

Of the aliphatic amines, secondary aliphatic amines and tertiary aliphatic amines are preferred.
An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of aliphatic amines include amines in which at least one hydrogen atom of ammonia _NH3 is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms (alkylamines or alkyl alcohol amines), or cyclic amines.
Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; dialkylamines such as diethylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, and dicyclohexylamine; trialkylamines such as 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, and tri-n-dodecylamine; and alkyl alcohol amines such as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, and tri-n-octanolamine. Among these, trialkylamines having 5 to 10 carbon atoms are more preferred, and tri-n-pentylamine or tri-n-octylamine is particularly preferred.

Examples of cyclic amines include heterocyclic compounds containing a nitrogen atom as a heteroatom. The heterocyclic compounds may be monocyclic (aliphatic monocyclic amines) or polycyclic (aliphatic polycyclic amines).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
The aliphatic polycyclic amine is preferably one having 6 to 10 carbon atoms, and specific examples thereof include 1,5-diazabicyclo[4.3.0]-5-nonene, 1,8-diazabicyclo[5.4.0]-7-undecene, hexamethylenetetramine, and 1,4-diazabicyclo[2.2.2]octane.

Other aliphatic amines include tris(2-methoxymethoxyethyl)amine, tris{2-(2-methoxyethoxy)ethyl}amine, tris{2-(2-methoxyethoxymethoxy)ethyl}amine, tris{2-(1-methoxyethoxy)ethyl}amine, tris{2-(1-ethoxyethoxy)ethyl}amine, tris{2-(1-ethoxypropoxy)ethyl}amine, tris[2-{2-(2-hydroxyethoxy)ethoxy}ethyl]amine, triethanolamine triacetate, etc., with triethanolamine triacetate being preferred.

Aromatic amines include 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, tribenzylamine, aniline compounds, N-tert-butoxycarbonylpyrrolidine, etc.

The component (D1) may be used alone or in combination of two or more types.
Of the above, the component (D1) is preferably an aromatic amine, and more preferably an aniline compound, such as 2,6-diisopropylaniline, N,N-dimethylaniline, N,N-dibutylaniline, or N,N-dihexylaniline.

Regarding the component (D2) There are no particular limitations on the component (D2) so long as it decomposes upon exposure to light and loses its acid diffusion controllability, and the component (D2) is preferably one or more compounds selected from the group consisting of a compound represented by the following general formula (d2-1) (hereinafter referred to as "component (d2-1)"), a compound represented by the following general formula (d2-2) (hereinafter referred to as "component (d2-2)"), and a compound represented by the following general formula (d2-3) (hereinafter referred to as "component (d2-3)"):
The components (d2-1) to (d2-3) decompose in the exposed areas of the resist film and lose their acid diffusion control ability (basicity), and therefore do not act as quenchers, but act as quenchers in the unexposed areas of the resist film.

［式中、Ｒｄ^１～Ｒｄ^４は置換基を有してもよい環式基、置換基を有してもよい鎖状のアルキル基、又は置換基を有してもよい鎖状のアルケニル基である。但し、一般式（ｄ２－２）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が結合していないものとする。Ｙｄ^１は単結合又は２価の連結基である。ｍは１以上の整数であって、Ｍ’^ｍ＋はそれぞれ独立にｍ価のオニウムカチオンである。］

[In the formula, Rd ¹ to Rd ⁴ are a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent. However, in Rd ² in general formula (d2-2), a fluorine atom is not bonded to the carbon atom adjacent to the S atom. Yd ¹ is a single bond or a divalent linking group. m is an integer of 1 or more, and M' ^m+ are each independently an m-valent onium cation.]

{(d2-1) component}
Anion Moiety In formula (d2-1), Rd ¹ represents a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a chain-like alkenyl group which may have a substituent, and examples of these groups include the same as R ¹⁰¹ in formula (b-1) above.
Among these, Rd ¹ is preferably an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain-like alkyl group which may have a substituent. Examples of the substituent which these groups may have include a hydroxyl group, an oxo group, an alkyl group, an aryl group, a fluorine atom, a fluorinated alkyl group, a lactone-containing cyclic group represented by each of the above general formulas (a2-r-1) to (a2-r-7), an ether bond, an ester bond, or a combination thereof. When an ether bond or an ester bond is contained as a substituent, it may be via an alkylene group, and in this case, the substituent is preferably a linking group represented by each of the above formulas (y-al-1) to (y-al-5).
Suitable examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, and a polycyclic structure containing a bicyclooctane skeleton (for example, a polycyclic structure consisting of a bicyclooctane skeleton ring structure and another ring structure).
The aliphatic cyclic group is more preferably a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane.
The chain alkyl group preferably has 1 to 10 carbon atoms. Specific examples of the chain alkyl group include linear alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group; and branched alkyl groups such as a 1-methylethyl group, a 1-methylpropyl group, a 2-methylpropyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 3-methylbutyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group, and a 4-methylpentyl group.

When the chain-like alkyl group is a fluorinated alkyl group having a fluorine atom or a fluorinated alkyl group as a substituent, the number of carbon atoms in the fluorinated alkyl group is preferably 1 to 11, more preferably 1 to 8, and even more preferably 1 to 4. The fluorinated alkyl group may contain an atom other than a fluorine atom. Examples of the atom other than a fluorine atom include an oxygen atom, a sulfur atom, and a nitrogen atom.
^Rd1 is preferably a fluorinated alkyl group in which some or all of the hydrogen atoms constituting a linear alkyl group have been substituted with fluorine atoms, and particularly preferably a fluorinated alkyl group in which all of the hydrogen atoms constituting a linear alkyl group have been substituted with fluorine atoms (linear perfluoroalkyl group).

Specific examples of preferred anion moieties of component (d2-1) are shown below.

Cation Moiety In formula (d2-1), ^M'm+ is an onium cation having a valence of m.
Suitable examples of the onium cation of M'm ⁺ include the same cations represented by the general formulae (ca-1) to (ca-4), more preferably the cation represented by the general formula (ca-1), and even more preferably the cations represented by the general formulae (ca-1-1) to (ca-1-78), (ca-1-101) to (ca-1-149).
The component (d2-1) may be used alone or in combination of two or more.

{(d2-2) component}
Anion Moiety In formula (d2-2), ^Rd2 represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and examples thereof include the same as R ¹⁰¹ in formula (b-1).
However, in Rd ² , the carbon atom adjacent to the S atom does not have a fluorine atom bonded thereto (is not substituted with fluorine), whereby the anion of the component (d2-2) becomes an appropriately weak acid anion, and the quenching ability of the component (D2) is improved.
^Rd2 is preferably a chain alkyl group which may have a substituent, or an aliphatic cyclic group which may have a substituent. The chain alkyl group preferably has 1 to 10 carbon atoms, and more preferably has 3 to 10 carbon atoms. The aliphatic cyclic group is more preferably a group (which may have a substituent) in which one or more hydrogen atoms have been removed from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, or the like; or a group in which one or more hydrogen atoms have been removed from camphor, or the like.
The hydrocarbon group of ^Rd2 may have a substituent, and examples of the substituent include the same as the substituents that may be possessed by the hydrocarbon group (aromatic hydrocarbon group, aliphatic cyclic group, chain alkyl group) in ^Rd1 of the above formula (d2-1).

Specific examples of preferred anion moieties of component (d2-2) are shown below.

Cation Moiety In formula (d2-2), M' ^m+ represents an onium cation having a valence of m and is the same as M' ^m+ in formula (d2-1).
The component (d2-2) may be used alone or in combination of two or more.

{(d2-3) component}
Anion portion In formula (d2-3), Rd ³ is a cyclic group which may have a substituent, a chain-like alkyl group which may have a substituent, or a chain-like alkenyl group which may have a substituent, and examples thereof include the same as R ¹⁰¹ in formula (b-1), and is preferably a cyclic group, a chain-like alkyl group, or a chain-like alkenyl group containing a fluorine atom. Among these, a fluorinated alkyl group is preferred, and the same as the fluorinated alkyl group of Rd ¹ is more preferred.

In formula (d2-3), ^Rd4 represents a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a chain alkenyl group which may have a substituent, and examples of Rd4 include the same as ^R101 in formula (b-1).
Among these, an alkyl group, an alkoxy group, an alkenyl group, or a cyclic group, which may have a substituent, is preferable.
The alkyl group in Rd ⁴ is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof 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, a neopentyl group, etc. A part of the hydrogen atoms of the alkyl group in Rd ⁴ may be substituted with a hydroxyl group, a cyano group, etc.
The alkoxy group in Rd ⁴ is preferably an alkoxy group having 1 to 5 carbon atoms, and specific examples of the alkoxy group having 1 to 5 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group. Of these, a methoxy group and an ethoxy group are preferable.

The alkenyl group in Rd ⁴ is the same as R ¹⁰¹ in the formula (b-1), and is preferably a vinyl group, a propenyl group (allyl group), a 1-methylpropenyl group, or a 2-methylpropenyl group. These groups may further have an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms as a substituent.

Examples of the cyclic group in Rd ⁴ include the same as R ¹⁰¹ in formula (b-1) above, and are preferably an alicyclic group in which one or more hydrogen atoms have been removed from a cycloalkane such as cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc., or an aromatic group such as a phenyl group, naphthyl group, etc. When Rd ⁴ is an alicyclic group, the resist composition dissolves well in an organic solvent, resulting in good lithography properties.

In formula (d2-3), ^Yd1 represents a single bond or a divalent linking group.
The divalent linking group for Yd ¹ is not particularly limited, and examples thereof include a divalent hydrocarbon group which may have a substituent (an aliphatic hydrocarbon group, an aromatic hydrocarbon group), a divalent linking group containing a hetero atom, etc. These include the same as the divalent hydrocarbon group which may have a substituent and the divalent linking group containing a hetero atom mentioned in the description of the divalent linking group for Ya ^x1 in the above formula (a10-1).
^Yd1 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 further preferably a methylene group or an ethylene group.

Specific examples of preferred anion moieties of component (d2-3) are shown below.

Cation Moiety In formula (d2-3), M' ^m+ represents an onium cation having a valence of m and is the same as M' ^m+ in formula (d2-1).
The component (d2-3) may be used alone or in combination of two or more.

The component (D2) may be any one of the above components (d2-1) to (d2-3), or a combination of two or more of them.
When the resist composition contains the component (D2), the amount of the component (D2) in the resist composition relative to 100 parts by mass of the component (A) is preferably 0.5 to 35 parts by mass, more preferably 1 to 25 parts by mass, even more preferably 2 to 20 parts by mass, and particularly preferably 3 to 15 parts by mass.
When the content of the component (D2) is at least the preferred lower limit, particularly good lithography properties and resist pattern shape are likely to be obtained, while when it is no more than the upper limit, a balance with other components can be achieved and various lithography properties are improved.

Production method of component (D2):
The method for producing the components (d2-1) and (d2-2) is not particularly limited, and they can be produced by known methods.
The method for producing the component (d2-3) is not particularly limited, and it can be produced, for example, in the same manner as the method described in US 2012-0149916.

<<Component (E): at least one compound selected from the group consisting of organic carboxylic acids, phosphorus oxoacids, and derivatives thereof>>
For the purposes of preventing deterioration of sensitivity and improving the resist pattern shape and storage stability, etc., the resist composition of this embodiment may contain, as an optional component, at least one compound (E) (hereafter referred to as "component (E)") selected from the group consisting of organic carboxylic acids, phosphorus oxoacids, and derivatives thereof.
Suitable organic carboxylic acids include, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid.
Examples of phosphorus oxoacids include phosphoric acid, phosphonic acid, and phosphinic acid, with phosphonic acid being particularly preferred.
Examples of the derivatives of phosphorus oxoacids include esters in which the hydrogen atoms of the above oxoacids are substituted with hydrocarbon groups. Examples of the hydrocarbon groups include alkyl groups having 1 to 5 carbon atoms and aryl groups having 6 to 15 carbon atoms.
Examples of the derivatives of phosphoric acid include phosphoric acid esters such as di-n-butyl phosphoric acid ester and diphenyl phosphoric acid ester.
Examples of the derivatives of phosphonic acid include phosphonic acid esters such as dimethyl phosphonate, di-n-butyl phosphonate, phenylphosphonic acid, diphenyl phosphonate, and dibenzyl phosphonate.
Derivatives of phosphinic acid include phosphinic acid esters and phenylphosphinic acid.
In the resist composition of this embodiment, the component (E) may use either a single type, or a combination of two or more types.
When the resist composition contains the component (E), the amount of the component (E) is typically within a range from 0.01 to 5 parts by mass per 100 parts by mass of the component (A).

<<Component (F): Fluorine Additive Component>>
The resist composition of this embodiment may contain a fluorine additive component (hereafter referred to as “component (F)”) in order to impart water repellency to the resist film or to improve lithography properties.
As the component (F), for example, the fluorine-containing polymeric compounds described in JP-A-2010-002870, JP-A-2010-032994, JP-A-2010-277043, JP-A-2011-13569, and JP-A-2011-128226 can be used.
More specifically, the component (F) may be a polymer having a structural unit (f1) represented by the following formula (f1-1). This polymer is preferably a polymer (homopolymer) consisting only of the structural unit (f1) represented by the following formula (f1-1); a copolymer of the structural unit (f1) and the structural unit (a1); or a copolymer of the structural unit (f1), a structural unit derived from acrylic acid or methacrylic acid, and the structural unit (a1). Here, the structural unit (a1) copolymerized with the structural unit (f1) is preferably a structural unit derived from 1-ethyl-1-cyclooctyl (meth)acrylate or a structural unit derived from 1-methyl-1-adamantyl (meth)acrylate.

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

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

In formula (f1-1), R bonded to the carbon atom at the α-position is the same as defined above. R is preferably a hydrogen atom or a methyl group.
In formula (f1-1), examples of halogen atoms of Rf ¹⁰² and Rf ¹⁰³ include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc., with fluorine atoms being particularly preferred. Examples of alkyl groups having 1 to 5 carbon atoms of Rf ¹⁰² and Rf ¹⁰³ include the same as the alkyl groups having 1 to 5 carbon atoms of R above, with methyl groups or ethyl groups being preferred. Specific examples of halogenated alkyl groups having 1 to 5 carbon atoms of Rf ¹⁰² and Rf ¹⁰³ include groups in which some or all of the hydrogen atoms of an alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. Examples of the halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc., with fluorine atoms being particularly preferred. Among these, examples of Rf ¹⁰² and Rf ¹⁰³ include hydrogen atoms, fluorine atoms, or alkyl groups having 1 to 5 carbon atoms, with hydrogen atoms, fluorine atoms, methyl groups, or ethyl groups being preferred.
In formula (f1-1), nf ¹ represents an integer of 1 to 5, preferably an integer of 1 to 3, and more preferably 1 or 2.

In formula (f1-1), Rf ¹⁰¹ is an organic group containing a fluorine atom, and is preferably a hydrocarbon group containing a fluorine atom.
The fluorine atom-containing hydrocarbon group may be linear, branched, or cyclic and preferably has 1 to 20 carbon atoms, more preferably has 1 to 15 carbon atoms, and particularly preferably has 1 to 10 carbon atoms.
In addition, in the hydrocarbon group containing fluorine atoms, preferably 25% or more of the hydrogen atoms in the hydrocarbon group are fluorinated, more preferably 50% or more, and particularly preferably 60% or more are fluorinated, as this enhances the hydrophobicity of the resist film during immersion exposure.
Of these, Rf ¹⁰¹ is more preferably a fluorinated hydrocarbon group having 1 to 6 carbon atoms, with a trifluoromethyl group, -CH ₂ -CF ₃ , -CH ₂ -CF ₂ -CF ₃ , -CH(CF ₃ ) ₂ , -CH ₂ -CH 2 -CF ₃ , and -CH ₂ -CH ₂ -CF ₂ -CF ₂ -CF _{2 -CF 3 being} particularly preferred.

The mass average molecular weight (Mw) of component (F) (based on polystyrene equivalent measured by gel permeation chromatography) is preferably from 1,000 to 50,000, more preferably from 5,000 to 40,000, and most preferably from 10,000 to 30,000. When it is below the upper limit of this range, the compound has sufficient solubility in a resist solvent for use as a resist, and when it is above the lower limit of this range, the resist film has good water repellency.
The dispersity (Mw/Mn) of the component (F) is preferably from 1.0 to 5.0, more preferably from 1.0 to 3.0, and most preferably from 1.2 to 2.5.

In the resist composition of this embodiment, the component (F) may use either a single type, or a combination of two or more types.
When the resist composition contains the component (F), the component (F) is typically used in an amount of 0.5 to 10 parts by mass per 100 parts by mass of the component (A).

<Component (S): Organic Solvent Component>
The resist composition of this embodiment can be produced by dissolving the resist materials in an organic solvent component (hereafter referred to as “component (S)”).
The component (S) can be any solvent that is capable of dissolving the individual components used and forming a homogeneous solution, and any solvent can be appropriately selected from those known in the art as a solvent for chemically amplified resist compositions.
Examples of the component (S) include lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, and dipropylene glycol monoacetate; and compounds having an ether bond such as monoalkyl ethers, monoethyl ethers, monopropyl ethers, and monobutyl ethers of the polyhydric alcohols or compounds having an ester bond, or monophenyl ethers. and derivatives of polyhydric alcohols such as those listed above (among which, propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred)]; cyclic ethers such as dioxane, esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, and ethyl ethoxypropionate; aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, and mesitylene, and dimethyl sulfoxide (DMSO).
In the resist composition of this embodiment, the component (S) may be used in the form of a single solvent, or a mixed solvent of two or more different solvents.
Of these, PGMEA, PGME, γ-butyrolactone, EL, and cyclohexanone are preferred.
A mixed solvent obtained by mixing PGMEA and a polar solvent is also preferred. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, and is preferably within a range of 1:9 to 9:1, and more preferably 2:8 to 8:2.
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 7:3. Furthermore, a mixed solvent of PGMEA, PGME, and cyclohexanone is also preferred.
As the component (S), a mixed solvent of at least one selected from PGMEA and EL with γ-butyrolactone is also preferred. In this case, the mixing ratio of the former to the latter is preferably 70:30 to 95:5 by mass.
There are no particular limitations on the amount of the component (S) used, and it is set appropriately depending on the coating film thickness so as to provide a concentration that allows application to a substrate, etc. In general, the component (S) is used so that the solids concentration of the resist composition falls within the range of 0.1 to 50 mass %, and preferably 10 to 50 mass %.

The resist composition of this embodiment may further contain miscible additives, such as additional resins for improving the performance of the resist film, dissolution inhibitors, plasticizers, stabilizers, colorants, antihalation agents, dyes, etc., as desired.

After dissolving the resist material in the (S) component, the resist composition of this embodiment may be subjected to removal of impurities using a polyimide porous film, a polyamideimide porous film, or the like. For example, the resist composition may be filtered using a filter made of a polyimide porous film, a filter made of a polyamideimide porous film, or a filter made of a polyimide porous film and a polyamideimide porous film. Examples of the polyimide porous film and the polyamideimide porous film include those described in JP 2016-155121 A.

The negative resist composition of this embodiment contains a polymer compound (A1), an acid generator (B0), a crosslinking agent (C), and an aromatic compound (Z) that has one or two phenolic hydroxyl groups and no carboxy group in the molecule.
As a result of the investigations conducted by the present inventors, when a resist pattern is formed using a negative resist composition that employs an alkali-soluble polyhydroxystyrene resin as a base component, wet etching resistance may be insufficient when a thick resist film of micron order is formed using the resist composition and then etched. This is believed to be because the resist film formed using the negative resist composition has insufficient adhesion to the substrate interface.
It is presumed that in the resist composition of this embodiment described above, the component (Z) segregates in the lower layer of the resist film, contributing to improved adhesion to the substrate, and therefore that the resist pattern formed using the negative resist composition of this embodiment exhibits good etching resistance.

(Method of forming a resist pattern)
A second aspect of the present invention is a method for forming a resist pattern, comprising: a step (i) of forming a resist film on a support using the resist composition related to the first aspect described above; a step (ii) of exposing the resist film to light; and a step (iii) of developing the exposed resist film to form a resist pattern.
One embodiment of the resist pattern forming method is, for example, a resist pattern forming method carried out as follows.

Step (i):
First, the resist composition of the above-described embodiment is applied onto a support using a spinner or the like, and then baked (post-applied bake (PAB)) at a temperature of, for example, 80 to 160° C. for 40 to 200 seconds, preferably 60 to 150 seconds, to form a resist film.

Step (ii):
Next, the resist film is selectively exposed, for example, by exposure through a mask (mask pattern) having a predetermined pattern formed thereon, using an exposure device such as a KrF exposure device, and then baked (post-exposure bake (PEB)) at a temperature of, for example, 80 to 150° C. for 40 to 150 seconds, preferably 60 to 120 seconds.

Step (iii):
Next, the resist film is developed using an alkaline developer in the case of an alkaline development process, or a developer containing an organic solvent (organic developer) in the case of a solvent development process.
After the development process, a rinse process is preferably carried out. In the case of an alkaline development process, the rinse process is preferably a water rinse using pure water, and in the case of a solvent development process, a rinse liquid containing an organic solvent is preferably used.
In the case of a solvent development process, after the development treatment or rinsing treatment, a treatment may be carried out in which the developer or rinsing liquid adhering to the pattern is removed by using a supercritical fluid.

After the development or rinsing process, drying is performed. In some cases, a baking process (post-baking) may be performed after the development process. The baking process (post-baking) is performed, for example, at a temperature of 80° C. or higher, preferably 90 to 120° C., for 10 to 120 seconds, preferably 300 to 90 seconds.
In this manner, a resist pattern can be formed.

The support is not particularly limited, and conventionally known supports can be used, such as substrates for electronic components and substrates on which a predetermined wiring pattern is formed. More specifically, the support includes substrates made of metals such as silicon wafers, copper, chromium, iron, and aluminum, and glass substrates. Materials for the wiring pattern include, for example, copper, aluminum, nickel, and gold.
The support may be a substrate as described above on which an inorganic and/or organic film is provided. Examples of inorganic films include inorganic anti-reflective coatings (inorganic BARC). Examples of organic films include organic anti-reflective coatings (organic BARC) and organic films such as lower organic films in a multi-layer resist method.
Here, the multi-layer resist method is a method in which at least one organic film (lower organic film) and at least one resist film (upper resist film) are provided on a substrate, and the lower organic film is patterned using the resist pattern formed on the upper resist film as a mask, and it is said that a pattern with a high aspect ratio can be formed. That is, according to the multi-layer resist method, the required thickness can be secured by the lower organic film, so that the resist film can be made thin, and a fine pattern with a high aspect ratio can be formed.
Multilayer resist methods are basically divided into a method in which a two-layer structure consisting of an upper resist film and a lower organic film is formed (two-layer resist method), and a method in which a multilayer structure consisting of three or more layers is formed by providing one or more intermediate layers (such as a metal thin film) between an upper resist film and a lower organic film (three-layer resist method).

The resist pattern forming method of the embodiment is a useful method for forming a thick resist film. Even if the resist film formed in step (i) has a thickness of, for example, 1 to 10 μm, a resist pattern can be stably formed with a good shape.

The wavelength used for exposure is not particularly limited, and exposure can be performed using ultraviolet light such as g-line or i-line, ArF excimer laser light, KrF excimer laser light, _F2 excimer laser light, EUV (extreme ultraviolet light), VUV (vacuum ultraviolet light), EB (electron beam), X-rays, soft X-rays, or other radiation.
The resist composition according to the first aspect described above is highly useful for use with ultraviolet light such as g-line or i-line, KrF excimer laser light, ArF excimer laser light, EB or EUV, is even more useful for use with ultraviolet light such as g-line or i-line, KrF excimer laser light, and ArF excimer laser light, and is particularly useful for use with ultraviolet light such as g-line or i-line, and KrF excimer laser light. The method of forming a resist pattern according to the second aspect is a method that is particularly suitable for use in irradiating the resist film with ultraviolet light such as g-line or i-line, or KrF excimer laser light in the step (ii).

The exposure method for the resist film may be a normal exposure method (dry exposure) performed in air or an inert gas such as nitrogen, or may be liquid immersion exposure (liquid immersion lithography).
Immersion exposure is an exposure method in which the space between the resist film and the lowest lens of the exposure tool is filled with a solvent (immersion medium) that has a refractive index greater than that of air, and exposure (immersion exposure) is then performed in that state.
The immersion medium is preferably a solvent having a refractive index larger than that of air and smaller than that of the resist film to be exposed. The refractive index of the solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger than that of air and smaller than that of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.
Specific _examples of the _fluorine -based inert liquid include liquids mainly composed of fluorine-based compounds such as _C3HCl2F5 , _C4F9OCH3 , _C4F9OC2H5 , _{and C5H3F7} , and preferably have a boiling point of 70 _{to 180} ° C., more preferably ₈₀ to 160° _C. If the _fluorine -based inert liquid has _a boiling point in the above range, it is preferable because the medium used for immersion can be removed in a simple manner after exposure is completed.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are replaced with fluorine atoms is particularly preferred. Specific examples of the perfluoroalkyl compound include perfluoroalkyl ether compounds and perfluoroalkylamine compounds.
More specifically, the perfluoroalkyl ether compound may be perfluoro(2-butyl-tetrahydrofuran) (boiling point: 102° C.), and the perfluoroalkylamine compound may be perfluorotributylamine (boiling point: 174° C.).
As the liquid immersion medium, water is preferably used from the viewpoints of cost, safety, environmental issues, versatility, and the like.

The alkaline developer used in the development treatment in the alkaline development process may be, for example, a 0.1 to 10% by weight aqueous solution of tetramethylammonium hydroxide (TMAH).
The organic solvent contained in the organic developer used in the development treatment in the solvent development process may be any organic solvent capable of dissolving the component (A) (the component (A) before exposure), and may be appropriately selected from known organic solvents. Specific examples of the organic solvent include polar solvents such as ketone solvents, ester solvents, alcohol solvents, nitrile solvents, amide solvents, and ether solvents, and hydrocarbon solvents.
Ketone-based solvents are organic solvents that contain C-C(=O)-C in their structure. Ester-based solvents are organic solvents that contain C-C(=O)-O-C in their structure. Alcohol-based solvents are organic solvents that contain an alcoholic hydroxyl group in their structure. "Alcoholic hydroxyl group" means a hydroxyl group bonded to a carbon atom of an aliphatic hydrocarbon group. Nitrile-based solvents are organic solvents that contain a nitrile group in their structure. Amide-based solvents are organic solvents that contain an amide group in their structure. Ether-based solvents are organic solvents that contain C-O-C in their structure.
Some organic solvents contain multiple types of functional groups that characterize the above-mentioned solvents in their structures, and in such cases, the organic solvent is considered to fall under any of the solvent types that contain the functional groups possessed by the organic solvent. For example, diethylene glycol monomethyl ether is considered to fall under both the alcohol-based solvents and the ether-based solvents in the above classification.
The hydrocarbon solvent is a hydrocarbon solvent that is composed of a hydrocarbon that may be halogenated and has no substituents other than halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferred.
Of the above, the organic solvent contained in the organic developer is preferably a polar solvent, and more preferably a ketone solvent, an ester solvent, a nitrile solvent, or the like.

Examples of ketone solvents include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenylacetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methyl naphthyl ketone, isophorone, propylene carbonate, γ-butyrolactone, and methyl amyl ketone (2-heptanone). Of these, methyl amyl ketone (2-heptanone) is preferred as a ketone solvent.

Examples of ester solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, methoxyethyl acetate, ethoxyethyl acetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol Licorice monopropyl ether acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate Examples of the ester-based solvent include butyl acetate, butyl lactate, propyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, and propyl-3-methoxypropionate. Among these, butyl acetate is preferred as the ester-based solvent.

Examples of nitrile solvents include acetonitrile, propionitrile, valeronitrile, butyronitrile, etc.

The organic developer may contain known additives as necessary. Examples of such additives include surfactants. The surfactant is not particularly limited, but may be, for example, an ionic or nonionic fluorine-based and/or silicon-based surfactant. The surfactant is preferably a nonionic surfactant, more preferably a nonionic fluorine-based surfactant or a nonionic silicon-based surfactant.
When a surfactant is added, the amount of the surfactant added is usually from 0.001 to 5% by mass, preferably from 0.005 to 2% by mass, and more preferably from 0.01 to 0.5% by mass, based on the total amount of the organic developer.

The development process can be carried out by a known development method, such as a method of immersing the support in a developer for a certain period of time (dip method), a method of piling up the developer on the support surface by surface tension and leaving it still for a certain period of time (paddle method), a method of spraying the developer on the support surface (spray method), or a method of continuously applying developer while scanning a developer application nozzle at a constant speed onto a support rotating at a constant speed (dynamic dispense method).

The organic solvent contained in the rinse solution used in the rinsing treatment after the development treatment in the solvent development process can be selected appropriately from the organic solvents listed as the organic solvents used in the organic developer, and can be used if it is difficult to dissolve the resist pattern.Usually, at least one solvent selected from a hydrocarbon solvent, a ketone solvent, an ester solvent, an alcohol solvent, an amide solvent, and an ether solvent is used.Among these, at least one solvent selected from a hydrocarbon solvent, a ketone solvent, an ester solvent, an alcohol solvent, and an amide solvent is preferred, at least one solvent selected from an alcohol solvent and an ester solvent is more preferred, and an alcohol solvent is particularly preferred.
The alcohol-based solvent used in the rinse liquid is preferably a monohydric alcohol having 6 to 8 carbon atoms, and the monohydric alcohol may be any of linear, branched, and cyclic. Specific examples include 1-hexanol, 1-heptanol, 1-octanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, and benzyl alcohol. Among these, 1-hexanol, 2-heptanol, and 2-hexanol are preferred, and 1-hexanol and 2-hexanol are more preferred.
These organic solvents may be used alone or in combination of two or more. They may also be used in combination with other organic solvents or water. However, in consideration of development characteristics, the amount of water in the rinse solution is preferably 30% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 3% by mass or less, based on the total amount of the rinse solution.
The rinse solution may contain known additives as necessary. Examples of such additives include surfactants. The surfactants include the same as those described above, and nonionic surfactants are preferred, and nonionic fluorine-based surfactants or nonionic silicon-based surfactants are more preferred.
When a surfactant is added, the amount of the surfactant added is usually 0.001 to 5 mass %, preferably 0.005 to 2 mass %, and more preferably 0.01 to 0.5 mass %, based on the total amount of the rinse solution.

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

In the resist pattern forming method of the present embodiment described above, the resist composition according to the first aspect described above is used, so it is presumed that a resist pattern with good etching resistance is obtained.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

<Preparation of Resist Composition>
(Examples 1 to 12, Comparative Examples 1 to 5)
The components shown in Tables 1 and 2 were mixed and dissolved to prepare resist compositions of each example.

In Tables 1 and 2, the abbreviations have the following meanings: The numbers in brackets [ ] are the amounts blended (parts by mass).
(A)-1: A polymer compound represented by the following chemical formula (A-1). This polymer compound (A-1) was obtained by radical polymerization using monomers that derive the structural units constituting the polymer compound in a predetermined molar ratio. The weight average molecular weight (Mw) of this polymer compound (A-1) measured by GPC was 2500 in terms of standard polystyrene, and the molecular weight dispersity (Mw/Mn) was 1.2. The copolymer composition ratio (the proportion (molar ratio) of each structural unit in the structural formula) measured by ¹³ C-NMR was l/m=90/10.

（Ａ）－２：下記の化学式（Ａ－２）で表される高分子化合物（ホモポリマー）。この高分子化合物（Ａ－２）は、該高分子化合物を構成する構成単位を誘導するモノマー（ヒドロキシスチレン）をラジカル重合させることによって得た。この高分子化合物（Ａ－２）について、ＧＰＣ測定により求めた標準ポリスチレン換算の重量平均分子量（Ｍｗ）は２５００、分子量分散度（Ｍｗ／Ｍｎ）は１．２。

(A)-2: A polymeric compound (homopolymer) represented by the following chemical formula (A-2). This polymeric compound (A-2) was obtained by radical polymerization of a monomer (hydroxystyrene) that derives the structural units that constitute the polymeric compound. The weight average molecular weight (Mw) of this polymeric compound (A-2) calculated as standard polystyrene by GPC measurement was 2500, and the molecular weight dispersity (Mw/Mn) was 1.2.

(B)-1 to (B)-3: Acid generators consisting of compounds represented by the following chemical formulas (B-1) to (B-3), respectively.

(C)-1: A crosslinking agent consisting of a compound represented by the following chemical formula (C-1).
(D)-1: A nitrogen-containing organic compound represented by the following chemical formula (D-1).

(Z)-1: A compound represented by the following chemical formula (Z-1). The mass average molecular weight (Mw) is 268.36.
(Z)-2: A compound represented by the following chemical formula (Z-2). The mass average molecular weight (Mw) is 352.43.
(Z)-3: A compound represented by the following chemical formula (Z-3). The mass average molecular weight (Mw) is 246.31.
(Z)-11: A compound represented by the following chemical formula (Z-11). The mass average molecular weight (Mw) is 230.22.
(Z)-12: A compound represented by the following chemical formula (Z-12). The mass average molecular weight (Mw) is 278.22.
(Z)-13: A compound represented by the following chemical formula (Z-13). The mass average molecular weight (Mw) is 286.33.
(S)-1: Propylene glycol monomethyl ether acetate.

<Method of forming a resist pattern>
Step (i):
Each resist composition of the examples was applied using a spinner onto a silicon substrate that had been treated with hexamethyldisilazane (HMDS), and the applied resist composition was pre-baked (PAB) on a hot plate at 90° C. for 90 seconds, followed by drying to form a resist film with a thickness of 3 μm.
Step (ii):
Next, the resist film was selectively irradiated with a high pressure mercury lamp (365 nm) through a mask pattern using an i-line stepper (reduction projection exposure apparatus: NSR-2205i14E (Nikon Corporation; NA (numerical aperture) = 0.57, σ = 0.67)).
This was followed by a post-exposure bake (PEB) treatment at 110° C. for 60 seconds.
Step (iii):
Next, alkaline development was carried out using a 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution "NMD-3" (product name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) as a developer at 23° C. for 60 seconds.
Thereafter, a baking treatment (post-baking) was carried out at 100° C. for 60 seconds.
As a result, an isolated line pattern (hereinafter referred to as an "IS pattern") with a space width of 600 nm was formed.

<Undercut evaluation>
The cross-sectional shape of the IS pattern formed by the above-mentioned <Method of forming a resist pattern> was observed with a scanning electron microscope (product name: S4500; manufactured by Hitachi, Ltd.) and the undercut (a notch in the resist itself at the bottom of the resist pattern formed on the substrate) (nm) was evaluated. The results are shown in Tables 3 and 4.

<Wet etching resistance evaluation>
A part of the substrate on which the IS pattern had been formed by the above-mentioned resist pattern forming method was cut out and immersed in 23% buffered hydrofluoric acid for 12 minutes.
The cross-sectional shape of the IS pattern after immersion was observed with a scanning electron microscope (product name: S4500; manufactured by Hitachi, Ltd.) to evaluate side etching (cuts caused by etching at the interface between the resist film and the substrate) (μm). The results are shown in Tables 3 and 4.

The results shown in Tables 3 and 4 confirm that the resist patterns formed using the resist compositions of Examples 1 to 12 have good dry etching resistance and wet etching resistance.

Claims (5)

A polymeric compound (A1) having a structural unit (a10) represented by the following general formula (a10-1),
an acid generator (B0) represented by the following general formula (b0-1);
A crosslinking agent (C);
An aromatic compound (Z) having one or two phenolic hydroxyl groups and no carboxyl group in the molecule;
Contains
The negative resist composition, wherein the aromatic compound (Z) comprises at least one selected from the group consisting of compounds represented by the following general formula (z1-1) and compounds represented by the following general formula (z 2 -1 ):

[In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. Ya ^x1 is a single bond or a divalent linking group. Wa ^x1 is an aromatic hydrocarbon group which may have a substituent. n _ax1 is an integer of 1 or more.]

[In the formula, ^Rb1 is an organic group. ^Rb2 is a group represented by the following general formula (b0-r-1) or (b0-r-2).]

[In formula (b0-r-1), Rb ²⁰¹ and Rb ²⁰² are each independently an organic group. * represents a bond. In formula (b0-r-2), Xb represents a group that forms a cyclic group having a cyclic imide structure together with -(O=)C-N-C(=O)-. * represents a bond.]

[In formula (z1-1), V _z ¹ is a divalent linking group having neither a hydroxy group nor a carboxy group. In formula (z2-1), Rz ² is a hydrocarbon group. n1 is 1 or 2. n2 is an integer from 2 to 5, with the proviso that n1+n2≦6.] 2. The negative resist composition according to claim 1, wherein the aromatic compound (Z) contains at least one selected from the group consisting of compounds represented by the following general formula (z1-1-1) and compounds represented by the following general formula (z1-2-1):

[In the formula, R _z ¹¹ and R _z ¹² each independently represent an aromatic hydrocarbon group which may have a substituent, or R _z ¹¹ and R _z ¹² bond to each other to form an aliphatic ring.]

[In the formula, Rz ²¹ and Rz ²² each independently represent an aromatic hydrocarbon group.] The resist composition according to claim 1 or 2, wherein the content of the aromatic compound (Z) is 0.5 to 30 parts by mass per 100 parts by mass of the polymer compound (A1). The resist composition according to any one of claims 1 to 3, wherein the acid generator (B0) is at least one compound selected from the group consisting of the following general formulas (b0-1-1) to (b0-1-3), (b0-1-5), and (b0-1-6):

[In the formula, ^Rb11 and ^Rb21 each independently represent a non-aromatic group.]

[In the formula, Rb ¹² is an alkyl group. Rb ²² is an aromatic group.]

[In the formula, ^Rb13 is a hydrocarbon group which may have a substituent. nb3 is 2 or 3. Ab is a divalent or trivalent organic group.]

[In the formula, Rb ¹⁵ is an unsubstituted monovalent saturated hydrocarbon group, an unsaturated hydrocarbon group, or an aromatic group. Xb ⁵ is a group that forms a cyclic group having a cyclic imide structure together with -(O=)C-N-C(=O)-.]

[In the formula, Rb ¹⁶ is an alkyl group or an aromatic hydrocarbon group. Rb ²⁶¹ to Rb ²⁶³ each independently represent a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. nb6 is an integer of 0 to 5.] A method for forming a resist pattern, comprising the steps of forming a resist film on a support using the resist composition according to any one of claims 1 to 4, exposing the resist film, and developing the exposed resist film to form a resist pattern.