JP7253883B2 - Resist composition and resist pattern forming method - Google Patents

Description

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

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, the resist film is selectively exposed to light, and a development process is performed to form a resist pattern having a predetermined shape on the resist film. a process is performed. A resist material in which the exposed portion of the resist film becomes soluble in the developer is called a positive type, and a resist material in which the exposed portion of the resist film becomes insoluble in the developer is called a negative type.
2. Description of the Related Art In recent years, in the manufacture of semiconductor devices and liquid crystal display devices, advances in lithography technology have led to rapid miniaturization of patterns. As a technique for miniaturization, generally, the wavelength of the exposure light source is shortened (the energy is increased). Specifically, conventionally, ultraviolet rays represented by g-line and i-line have been used, but at present, semiconductor devices using KrF excimer laser light and ArF excimer laser light are mass-produced. . In addition, EUV (extreme ultraviolet rays), EB (electron beam), X-rays, etc., which have a shorter wavelength (higher energy) than these excimer laser beams, are also being studied.

Resist materials are required to have lithographic properties such as sensitivity to these exposure light sources and resolution capable of reproducing patterns with fine dimensions.
Conventionally, as a resist material that satisfies such requirements, a chemically amplified resist composition containing a base component whose solubility in a developing solution is changed by the action of an acid and an acid generator component that generates an acid upon exposure. is used.
For example, when the developer is an alkaline developer (alkaline development process), the positive chemically amplified resist composition includes a resin component (base resin) whose solubility in the alkaline developer is increased by the action of acid and an acid-generating agent components are generally used. When a resist film formed using such a resist composition is subjected to selective exposure during resist pattern formation, acid is generated from the acid generator component in the exposed area, and the action of the acid increases the polarity of the base resin. As a result, the exposed portion of the resist film becomes soluble in an alkaline developer. Therefore, by alkali development, a positive pattern is formed in which the unexposed portion of the resist film remains as a pattern.
On the other hand, when such a chemically amplified resist composition is applied to a solvent development process using a developer containing an organic solvent (organic developer), an increase in the polarity of the base resin results in relatively organic development. Since the solubility in the liquid decreases, the unexposed portion of the resist film is dissolved and removed by the organic developer, forming a negative resist pattern in which the exposed portion of the resist film remains as a pattern. Such a solvent development process for forming a negative resist pattern is sometimes called a negative development process.

So far, as a base resin for chemically amplified resist compositions, for example, polyhydroxystyrene (PHS), which has high transparency against KrF excimer laser light (248 nm), and its hydroxyl groups are protected with acid-dissociable, dissolution-inhibiting groups. A resin (PHS-based resin) or a resin ((meth)acrylic-based resin) in which the hydroxyl group in the carboxyl group of (meth)acrylic acid is protected with an acid-dissociable, dissolution-inhibiting group is used (see, for example, Patent Document 1). ).
Examples of the acid-dissociable, dissolution-inhibiting group include a so-called acetal group such as a chain ether group typified by a 1-ethoxyethyl group or a cyclic ether group typified by a tetrahydropyranyl group, and a tert-butyl group. A tertiary alkyl group, a tertiary alkoxycarbonyl group represented by a tert-butoxycarbonyl group, and the like are mainly used.

In addition, a wide variety of acid generator components have been proposed for use in chemically amplified resist compositions. Generators, diazomethane-based acid generators, nitrobenzylsulfonate-based acid generators, iminosulfonate-based acid generators, disulfone-based acid generators, and the like are known.

In recent years, photofabrication has become the mainstream of precision microfabrication technology. Photofabrication involves applying the chemically amplified resist composition to the surface of a workpiece to form a resist film, forming a resist pattern of a predetermined shape on the resist film, and using this as a mask, performing chemical etching, It refers to processing technology for manufacturing various precision parts by electroforming, which is mainly based on electrolytic etching or electroplating.
In such photofabrication, depending on the application, a thick resist film having a thickness of 8 μm or more is formed on the surface of the workpiece, a resist pattern is formed, and etching or the like is performed. There is

JP-A-4-211258

When forming a thick resist film using a chemically amplified resist composition, the thicker the resist film, the more uniform the chemically amplified resist composition should be applied onto the workpiece. becomes difficult. In addition, there is a problem that the formed resist pattern tends to have poor lithography characteristics (for example, dimensional uniformity).

Further, when forming a resist pattern using a chemically amplified resist composition, the thicker the resist film, the more difficult it becomes to maintain the sensitivity during exposure. On the other hand, for example, sensitivity can be improved by using a chemically amplified resist composition in which an iodonium salt is selected as an acid generator component.
However, in the studies of the present inventors, when a chemically amplified resist composition containing an iodonium salt is used, when the support on which the resist film is formed is baked at a high temperature (180 ° C. or higher) (for example, after development treatment) Or, a phenomenon of foaming was observed during the baking treatment (post-baking) performed after the rinsing treatment. Such a resist composition, which tends to cause bubbling, has problems such as an insufficient effect of removing residues during ashing treatment for rework, for example.

The present invention has been made in view of the above circumstances. An object of the present invention is to provide a resist composition in which foaming from a resist pattern during baking is suppressed, and a method for forming a resist pattern using the same.

In order to solve the above problems, the present invention employs the following configurations.
That is, a first aspect of the present invention is a resist composition that generates acid upon exposure and changes its solubility in a developer by the action of the acid, and is represented by the following general formula (a10-1): A polymer compound (A1) having a unit (a10) and a structural unit (a1) containing an acid-decomposable group whose polarity increases under the action of an acid, and an acid generator (B1) represented by the following general formula (b1) and a resist composition having a solid content concentration of 30% by mass or more.

［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、（ｎ_ａｘ１＋１）価の芳香族炭化水素基である。ｎ_ａｘ１は、１～３の整数である。Ｒ^２０１１、Ｒ^２０２１及びＲ^２０３１は、それぞれ独立に、置換基を有していてもよいアリール基を表す。Ｒ^２０１１、Ｒ^２０２１及びＲ^２０３１のうち２つ以上が相互に結合して、式中のイオウ原子と共に環を形成してもよい。Ｘ^－は、対アニオンを表す。］

[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 a (n _ax1 +1) valent aromatic hydrocarbon group. n _ax1 is an integer of 1-3. R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ each independently represent an optionally substituted aryl group. Two or more of R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ may combine with each other to form a ring together with the sulfur atom in the formula. X ⁻ represents a counter anion. ]

A second aspect of the present invention comprises a step (i) of forming a resist film on a support using the resist composition according to the first aspect, a step (ii) of exposing the resist film, and the A method of forming a resist pattern, comprising a step (iii) of developing the resist film after exposure to form a resist pattern.

According to the present invention, in the formation of a resist pattern, particularly when a thick resist film is formed, the lithography characteristics are excellent, the coatability is good, and foaming from the resist pattern during high-temperature baking is prevented. It is possible to provide a suppressed resist composition and a method of forming a resist pattern using the same.
The resist composition and resist pattern forming method of the present invention are particularly useful for forming thick-film resist patterns.

In the present specification and claims, "aliphatic" is defined relative to aromatic to mean groups, compounds, etc. that do not possess aromatic character.
"Alkyl group" includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified. The same applies to the alkyl group in the alkoxy group.
Unless otherwise specified, the "alkylene group" includes straight-chain, branched-chain and cyclic divalent saturated hydrocarbon groups.
A "halogenated alkyl group" is a group in which some or all of the hydrogen atoms of an alkyl group are substituted with halogen atoms, and the halogen atoms include fluorine, chlorine, bromine and iodine atoms.
A "fluorinated alkyl group" or "fluorinated alkylene group" refers to a group in which some or all of the hydrogen atoms of an alkyl group or alkylene group have been substituted with fluorine atoms.
A "structural unit" means a monomer unit (monomeric unit) that constitutes a polymer compound (resin, polymer, copolymer).
When describing "optionally having a substituent", when replacing a hydrogen atom (-H) with a monovalent group, and when replacing a methylene group (-CH ₂ -) with a divalent group and both.
“Exposure” is a concept that includes irradiation of radiation in general.

“(Meth)acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.
“(Meth)acrylate” means either or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position.
“(Meth)acrylic acid” means either or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position.

A “structural unit derived from an acrylic ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylic ester.
“Acrylic acid ester” is a compound in which the terminal hydrogen atom of the carboxy group of acrylic acid (CH ₂ ═CH—COOH) is substituted with an organic group.
In the acrylic acid ester, the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent. The substituent (R ^α0 ) substituting the hydrogen atom bonded to the α-position carbon atom is an atom or group other than a hydrogen atom, such as an alkyl group having 1 to 5 carbon atoms, a halogenated group having 1 to 5 carbon atoms, An alkyl group and the like can be mentioned. In addition, itaconic acid diesters in which the substituent (R ^α0 ) is substituted with a substituent containing an ester bond, and α-hydroxy acrylic esters in which the substituent (R ^α0 ) is substituted with a hydroxyalkyl group or a modified hydroxyl group thereof are also available. shall include Unless otherwise specified, the α-position carbon atom of the acrylic acid ester means the carbon atom to which the carbonyl group of acrylic acid is bonded.
Hereinafter, an acrylic acid ester in which the hydrogen atom bonded to the α-position carbon atom is substituted with a substituent may be referred to as an α-substituted acrylic acid ester. In addition, acrylic acid esters and α-substituted acrylic acid esters may be collectively referred to as "(α-substituted) acrylic acid esters".

A “structural unit derived from acrylamide” means a structural unit formed by cleavage of an ethylenic double bond of acrylamide.
In acrylamide, a hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent, and one or both hydrogen atoms of the amino group of acrylamide may be substituted with a substituent. Unless otherwise specified, the α-position carbon atom of acrylamide is the carbon atom to which the carbonyl group of acrylamide is bonded.
The substituent for substituting the hydrogen atom bonded to the carbon atom at the α-position of acrylamide is the same as the substituent at the α-position (substituent (R ^α0 )) in the α-substituted acrylic acid ester. mentioned.

A “structural unit derived from hydroxystyrene” means a structural unit formed by cleavage of an ethylenic double bond of hydroxystyrene. A “structural unit derived from a hydroxystyrene derivative” means a structural unit formed by cleavage of an ethylenic double bond of a hydroxystyrene derivative.
"Hydroxystyrene derivative" is a concept including hydroxystyrene in which the α-position hydrogen atom is substituted with another substituent such as an alkyl group or a halogenated alkyl group, and derivatives thereof. Derivatives thereof include those obtained by substituting the hydrogen atom of the hydroxyl group of hydroxystyrene with an organic group; Examples include those in which a substituent other than a hydroxyl group is bonded to the benzene ring of good hydroxystyrene. In addition, the α-position (the carbon atom at the α-position) refers to the carbon atom to which the benzene ring is bonded, unless otherwise specified.
Examples of the substituent for substituting the hydrogen atom at the α-position of hydroxystyrene include the same substituents at the α-position in the α-substituted acrylic acid ester.

A “structural unit derived from vinyl benzoic acid or a vinyl benzoic acid derivative” means a structural unit formed by cleavage of an ethylenic double bond of vinyl benzoic acid or a vinyl benzoic acid derivative.
The concept of "vinyl benzoic acid derivative" includes those in which the α-position hydrogen atom of vinyl benzoic acid is substituted with other substituents such as alkyl groups and halogenated alkyl groups, and derivatives thereof. Derivatives thereof include those in which the hydrogen atom of the carboxy group of vinylbenzoic acid, which may be substituted with a substituent at the α-position, is substituted with an organic group; Examples thereof include vinyl benzoic acid in which a substituent other than a hydroxyl group and a carboxy group is bonded to the benzene ring of vinyl benzoic acid. In addition, the α-position (the carbon atom at the α-position) refers to the carbon atom to which the benzene ring is bonded, unless otherwise specified.

The concept of "styrene" includes styrene and those in which the α-position hydrogen atom of styrene is substituted with another substituent such as an alkyl group or a halogenated alkyl group.
"Styrene derivative" is a concept including those in which the α-position hydrogen atom of styrene is substituted with other substituents such as alkyl groups and halogenated alkyl groups, and derivatives thereof. Examples of derivatives thereof include those in which a substituent is bonded to the benzene ring of hydroxystyrene in which the α-position hydrogen atom may be substituted with a substituent. The α-position (the carbon atom at the α-position) refers to the carbon atom to which the benzene ring is bonded, unless otherwise specified.
A "structural unit derived from styrene" and a "structural unit derived from a styrene derivative" mean a structural unit formed by cleavage of an ethylenic double bond of styrene or a styrene derivative.

The alkyl group as the α-position substituent is preferably a linear or branched alkyl group, and specifically, an alkyl group having 1 to 5 carbon atoms (methyl group, ethyl group, propyl group, isopropyl group , n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group) and the like.
Further, the halogenated alkyl group as a substituent at the α-position specifically includes a group in which some or all of the hydrogen atoms of the above-mentioned "alkyl group as a substituent at the α-position" are substituted with halogen atoms. be done. The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is particularly preferred.
Further, the hydroxyalkyl group as the α-position substituent specifically includes a group obtained by substituting some or all of the hydrogen atoms of the above “alkyl group as the α-position substituent” with a hydroxyl group. The number of hydroxyl groups in the hydroxyalkyl group is preferably 1-5, most preferably 1.

In the present specification and claims, some structures represented by chemical formulas may have asymmetric carbon atoms and may have enantiomers or diastereomers. In that case, one chemical formula represents those isomers. Those isomers may be used singly or as a mixture.

(Resist composition)
A first aspect of the present invention is a resist composition that generates an acid upon exposure and changes its solubility in a developer by the action of the acid.
As one embodiment of such a resist composition, a substrate component (A) (hereinafter also referred to as "(A) component") whose solubility in a developer changes due to the action of an acid, and an acid-generating component that generates acid upon exposure to light. and a resist composition containing an agent component (B) (hereinafter also referred to as "(B) component") and an organic solvent component (S) (hereinafter also referred to as "(S) component"). In the resist composition of the present embodiment, the component (A) contains a specific polymer compound (A1), the component (B) contains a specific acid generator (B1), and the solid in the resist composition concentration is 30% by mass or more.

The resist composition of this embodiment is suitable for forming a resist pattern by exposure using a KrF excimer laser.
In addition, the resist composition of the present embodiment is suitable for forming a resist film having a thickness of, for example, 1 to 10 μm on a support. It is suitable for forming. A thick film here means a film having a thickness of 6 μm or more. The resist composition of the present embodiment preferably has a thickness in the range of 6 μm or more, and within this range, it is suitable for forming a resist film having a thickness of 7 μm or more, and further a thickness of 8 μm or more. .

When a resist film is formed using the resist composition of the present embodiment, and the resist film is selectively exposed to light, acid is generated from the component (B) in the exposed portion of the resist film, and the action of the acid While the solubility of component (A) in the developer changes, the solubility of component (A) in the developer does not change in the unexposed portion of the resist film, so the exposed portion and the unexposed portion of the resist film There is a difference in solubility in the developer between Therefore, when the resist film is developed, if the resist composition is positive, the exposed portion of the resist film is dissolved and removed to form a positive resist pattern, and if the resist composition is negative, the resist film is not formed. The exposed portion is dissolved and removed to form a negative resist pattern.

In this specification, a resist composition that forms a positive resist pattern by dissolving and removing the exposed portion of the resist film is referred to as a positive resist composition, and forming a negative resist pattern by dissolving and removing the unexposed portion of the resist film. A resist composition that does so is called a negative resist composition.
The resist composition of this embodiment may be a positive resist composition or a negative resist composition.
In addition, the resist composition of the present embodiment may be for an alkali development process using an alkali developer for development treatment at the time of resist pattern formation, and a developer containing an organic solvent (organic developer) for the development treatment. for solvent development processes using

The resist composition of this embodiment has an acid-generating ability to generate an acid upon exposure, and in addition to the component (B), the component (A) may also generate an acid upon exposure.
When the component (A) generates an acid upon exposure, this component (A) is a "base component that generates an acid upon exposure and changes its solubility in a developer by the action of the acid". When the component (A) is a substrate component that generates an acid upon exposure and changes its solubility in a developer by the action of the acid, the component (A1) described later generates an acid upon exposure and It is preferably a polymer compound whose solubility in a developer is changed by the action of an acid. Examples of such polymer compounds include resins having structural units that generate acid upon exposure. A known monomer can be used as a monomer that induces a structural unit that generates an acid upon exposure.

<(A) Component>
Component (A) is a base component whose solubility in a developer changes under the action of acid.
In the present invention, the "substrate component" is an organic compound having film-forming ability, preferably an organic compound having a molecular weight of 500 or more. When the molecular weight of the organic compound is 500 or more, the film-forming ability is improved, and in addition, it becomes easy to form a nano-level resist pattern.
The organic compounds used as base components are roughly classified into non-polymers and polymers.
As the non-polymer, one having a molecular weight of 500 or more and less than 4000 is usually used. Hereinafter, the term "low-molecular-weight compound" refers to a non-polymer having a molecular weight of 500 or more and less than 4,000.
As the polymer, those having a molecular weight of 1000 or more are usually used. Hereinafter, "resin", "polymer compound" or "polymer" refers to a polymer having a molecular weight of 1000 or more.
As the molecular weight of the polymer, a polystyrene-equivalent weight-average molecular weight obtained by GPC (gel permeation chromatography) is used.

As the (A) component used in the resist composition of the present embodiment, at least the (A1) component is used, and the (A1) component may be used in combination with other high-molecular compounds and/or low-molecular-weight compounds.

In the resist composition of the present embodiment, the component (A) comprises a specific polymer compound (A1), that is, a structural unit (a10) represented by the general formula (a10-1) described later and a polar polymer by the action of an acid. It contains a polymer compound (A1) having a structural unit (a1) containing an acid-decomposable group that increases the (hereinafter also referred to as "(A1) component").
When a resist film formed using a resist composition containing such a component (A1) is exposed to light, the structural unit (a1) has at least a partial bond in its structure cleaved by the action of an acid, and the polarity becomes Increase. Therefore, the resist composition of the present embodiment becomes negative when the developer is an organic developer (solvent development process), and becomes positive when the developer is an alkaline developer (alkali development process). Since the polarity of the component (A1) changes before and after exposure, the use of the component (A1) makes it possible to obtain good development contrast not only in the alkali development process but also in the solvent development process.
That is, when an alkaline development process is applied, the component (A1) is sparingly soluble in an alkaline developer before exposure. The increased polarity increases the solubility in alkaline developers. Therefore, in the formation of a resist pattern, when a resist film obtained by coating the resist composition on a support is selectively exposed to light, the exposed portion of the resist film changes from poorly soluble to soluble in an alkaline developer. On the other hand, since the unexposed portion of the resist film remains insoluble in alkali, a positive resist pattern is formed by alkali development.
On the other hand, when a solvent development process is applied, the component (A1) is highly soluble in an organic developer before exposure, and when an acid is generated from the component (B) by exposure, the action of the acid causes a polar becomes higher, and the solubility in an organic developer decreases. Therefore, in forming a resist pattern, when a resist film obtained by coating the resist composition on a support is selectively exposed to light, the exposed portion of the resist film changes from soluble to poorly soluble in an organic developer. On the other hand, the unexposed portion of the resist film remains soluble and does not change. Therefore, by developing with an organic developer, it is possible to create a contrast between the exposed portion and the unexposed portion, resulting in a negative resist pattern. It is formed.

About the (A1) component The (A1) component consists of a structural unit (a10) represented by the general formula (a10-1) and a structural unit (a1) containing an acid-decomposable group whose polarity increases under the action of an acid. is a polymer compound having

<<Structural unit (a10)>>
The structural unit (a10) is a structural unit represented by general formula (a10-1) 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、（ｎ_ａｘ１＋１）価の芳香族炭化水素基である。ｎ_ａｘ１は、１～３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 a (n _ax1 +1) valent aromatic hydrocarbon group. n _ax1 is an integer of 1-3. ]

In formula (a10-1) above, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.
The alkyl group having 1 to 5 carbon atoms of R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, specifically, methyl group, ethyl group, propyl group, isopropyl group, n- butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like. The halogenated alkyl group having 1 to 5 carbon atoms for R is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and 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 most preferably a hydrogen atom or a methyl group in view of industrial availability.

In the formula (a10-1), Ya ^x1 is a single bond or a divalent linking group.
As the divalent linking group for Ya ^x1 , for example, a divalent hydrocarbon group optionally having a substituent and a divalent linking group containing a hetero atom are preferred.

- A divalent hydrocarbon group which may have a substituent:
When Ya ^x1 is an optionally substituted divalent hydrocarbon group, 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 a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, and the like.

... Linear or branched aliphatic hydrocarbon group The linear aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and Numbers 1 to 4 are more preferred, and carbon numbers 1 to 3 are most preferred.
As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferable, and specifically, a methylene group [ _--CH.sub.2-- ], an ethylene group [--( _CH.sub.2 ) _.sub.2-- ], a trimethylene group [ -(CH ₂ ) ₃ -], tetramethylene group [-(CH ₂ ) ₄ -], pentamethylene group [-(CH ₂ ) ₅ -] and the like.
The branched chain aliphatic hydrocarbon group preferably has 3 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, still more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms.
The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specifically, -CH(CH ₃ )-, -CH(CH ₂ CH ₃ )-, -C(CH ₃ ) _2- , -C(CH ₃ )(CH ₂ CH ₃ )-, -C(CH ₃ )(CH ₂ CH ₂ CH ₃ )-, -C(CH ₂ CH ₃ ) ₂ - and other alkylmethylene groups;- CH(CH ₃ )CH ₂ -, -CH(CH ₃ )CH(CH ₃ )-, -C(CH ₃ ) ₂ CH ₂ -, -CH(CH ₂ CH ₃ )CH ₂ -, -C(CH ₂ Alkylethylene groups such as CH ₃ ) ₂ -CH ₂ -; alkyltrimethylene groups such as -CH(CH ₃ )CH ₂ CH ₂ - and -CH ₂ CH(CH ₃ )CH ₂ -; -CH(CH ₃ ) Examples include alkylalkylene groups such as alkyltetramethylene groups such as CH ₂ CH ₂ CH ₂ — and —CH ₂ CH(CH ₃ )CH ₂ CH ₂ —. As the alkyl group in the alkylalkylene group, a linear alkyl group having 1 to 5 carbon atoms is preferable.

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

... Aliphatic hydrocarbon group containing a ring in its structure The aliphatic hydrocarbon group containing a ring in its structure is a cyclic aliphatic hydrocarbon group which may contain a substituent containing a hetero atom in the ring structure. (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), a group in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, the cyclic aliphatic groups in which a group hydrocarbon group intervenes in the middle of a linear or branched aliphatic hydrocarbon group. Examples of the straight-chain or branched-chain aliphatic hydrocarbon group include those mentioned above.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 carbon atoms.
A cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic alicyclic hydrocarbon group, a group obtained by removing two hydrogen atoms from a monocycloalkane is preferable. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.

A cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group and the like.
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group or a tert-butyl group.
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 and a tert-butoxy group. A methoxy group and an ethoxy group are most preferred.
The halogen atom as the substituent includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.
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.
A part of the carbon atoms constituting the ring structure of the cyclic aliphatic hydrocarbon group may be substituted with a heteroatom-containing substituent. Preferred heteroatom-containing substituents are -O-, -C(=O)-O-, -S-, -S(=O) ₂ - and -S(=O) ₂ -O-.

Aromatic Hydrocarbon Group for Ya ^x1 The aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring.
This 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 aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, still more preferably 6 to 15 carbon atoms, and particularly preferably 6 to 12 carbon atoms. 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; mentioned. The heteroatom in the aromatic heterocycle includes oxygen atom, sulfur atom, nitrogen atom and the like. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings.
Specific examples of the aromatic hydrocarbon group include groups obtained by removing two hydrogen atoms from the above aromatic hydrocarbon ring or aromatic heterocycle (arylene group or heteroarylene group); aromatic compounds containing two or more aromatic rings A group obtained by removing two hydrogen atoms from (e.g., biphenyl, fluorene, etc.); One of the hydrogen atoms of the group obtained by removing one hydrogen atom from the aromatic hydrocarbon ring or aromatic heterocyclic ring (aryl group or heteroaryl group) A group in which one is substituted with an alkylene group (for example, a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, a hydrogen from an arylalkyl group such as a 2-naphthylethyl group) group from which one atom has been further removed), and the like. The alkylene group bonded to the aryl group or heteroaryl group preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

A hydrogen atom of the aromatic hydrocarbon group may be 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 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 for substituting the hydrogen atom of the cyclic aliphatic hydrocarbon group.

- A bivalent linking group containing a heteroatom:
When Ya ^x1 is a divalent linking group containing a hetero atom, the linking group is preferably -O-, -C(=O)-O-, -C(=O)-, -OC (=O) -O-, -C(=O)-NH-, -NH-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group or an acyl group ), -S-, -S(=O) ₂ -, -S(=O) ₂ -O-, 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 have a substituent and is a divalent hydrocarbon group, O is an oxygen atom, and m″ is an integer of 0-3. ] and the like.
The divalent linking group containing the heteroatom is -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, -NH-C(=NH )—, the H may be substituted with a substituent such as an alkyl group or acyl. 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.
general formulas -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 are each independently a divalent hydrocarbon group which may have a substituent. (divalent hydrocarbon group optionally having substituent(s)).
Y ²¹ is preferably a straight-chain aliphatic hydrocarbon group, more preferably a straight-chain alkylene group, more preferably a straight-chain alkylene group having 1 to 5 carbon atoms, particularly a methylene group or an ethylene group. preferable.
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 straight-chain alkyl group having 1 to 5 carbon atoms, more preferably a straight-chain 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, and 0 or 1 is more preferred, and 1 is particularly preferred. That is, the group represented by the formula -[Y ²¹ -C(=O)-O] _m″ -Y ²² - is represented by the formula -Y ²¹ -C(=O)-O-Y ²² - is particularly preferred, and among these, a group represented by the formula —(CH ₂ ) _a′ —C(═O)—O—(CH ₂ ) _b′ —, in which a′ is 1 to 10 is an integer of 1 to 8, preferably an integer of 1 to 5, more preferably 1 or 2, and most preferably 1. b' is an integer of 1 to 10, and 1 to 8 An integer is preferred, an integer from 1 to 5 is more preferred, 1 or 2 is more preferred, and 1 is most preferred.

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

In the formula (a10-1), Wa ^x1 is a (n _ax1 +1)-valent aromatic hydrocarbon group.
Examples of the aromatic hydrocarbon group for Wa ^x1 include groups obtained by removing (n _ax1 +1) hydrogen atoms from an aromatic ring. 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, still 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; mentioned. The heteroatom in the aromatic heterocycle includes oxygen atom, sulfur atom, nitrogen atom and the like. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings.

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

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

The structural unit (a10) contained in the component (A1) may be one type or two or more types.
Among the above, the structural unit (a10) is preferably a structural unit containing a hydroxystyrene skeleton, and particularly preferably a structural unit represented by the following general formula (a10-1-1).

［式中、Ｒ^ｓｔは、水素原子又はメチル基を表す。ｍ_０１は１～３の整数を表す。］

[In the formula, R ^st represents a hydrogen atom or a methyl group. _m01 represents an integer of 1-3. ]

The ratio of the structural unit (a10) in the component (A1) is preferably 10 to 95 mol%, preferably 30 to 90 mol%, relative to the total (100 mol%) of all structural units constituting the component (A1). is more preferred, and 50 to 85 mol % is particularly preferred.
By setting the ratio of the structural unit (a10) to the lower limit of the preferred range or more, lithography properties such as development characteristics and EL margin are further improved, and by setting the ratio to the upper limit of the preferred range or less, other It becomes easier to balance with the constituent units of

<<Constituent unit (a1)>>
The structural unit (a1) is a structural unit containing an acid-decomposable group whose polarity increases under the action of acid.
An "acid-decomposable group" is a group having acid-decomposability such that at least some of the bonds in the structure of the acid-decomposable group can be cleaved by the action of an acid.
The acid-decomposable group whose polarity is increased by the action of an acid includes, for example, a group that is decomposed by the action of an acid to form a polar group.
Polar groups include, for example, a carboxy group, a hydroxyl group, an amino group, and a sulfo group (--SO ₃ H). Among these, a polar group containing —OH in the structure (hereinafter sometimes referred to as an “OH-containing polar group”) is preferred, a carboxy group or a hydroxyl group is more preferred, and a carboxy group is particularly preferred.
More specifically, the acid-decomposable group includes a group in which the polar group is protected with an acid-labile group (for example, a group in which the hydrogen atom of the OH-containing polar group is protected with an acid-labile group).
The term "acid-dissociable group" as used herein means (i) a group having acid-dissociable properties 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; or (ii) after some bonds are cleaved by the action of an acid, a further decarboxylation reaction occurs to cleave the bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group; It refers to both the group to obtain.
The acid-labile group constituting the acid-labile group must be a group with a lower polarity than the polar group generated by the dissociation of the acid-labile group. When is dissociated, a polar group having a higher polarity than the acid-dissociable group is generated and the polarity is increased. As a result, the polarity of the entire component (A1) increases. As the polarity increases, the solubility in the developer relatively changes. When the developer is an alkaline developer, the solubility increases, and when the developer is an organic developer, the solubility increases. Decrease.

Examples of acid-dissociable groups include those that have hitherto been proposed as acid-dissociable groups for base resins for chemically amplified resists.
Specific examples of acid-dissociable groups proposed for base resins for chemically amplified resists include "acetal-type acid-dissociable groups" and "tertiary alkyl ester-type acid-dissociable groups" described below. , and “tertiary alkyloxycarbonyl acid dissociable group”.

- Acetal-type acid dissociable group:
Among the polar groups, the acid-dissociable group that protects the carboxy group or hydroxyl group includes, for example, an acid-dissociable group represented by the following general formula (a1-r-1) (hereinafter referred to as "acetal-type acid-dissociable group" There is a thing.) is mentioned.

［式中、Ｒａ’^１、Ｒａ’^２は、水素原子又はアルキル基である。Ｒａ’^３は炭化水素基であって、Ｒａ’^３は、Ｒａ’^１、Ｒａ’^２のいずれかと結合して環を形成してもよい。］

[In the formula, Ra' ¹ and Ra' ² are a hydrogen atom or an alkyl group. Ra' ³ is a hydrocarbon group, and Ra' ³ may combine with either Ra' ¹ or Ra' ² to form a ring. ]

In formula (a1-r-1), at least one of Ra' ¹ and Ra' ² is preferably a hydrogen atom, more preferably both are hydrogen atoms.
When Ra' ¹ or Ra' ² is an alkyl group, the alkyl group includes the alkyl group exemplified as the substituent that may be bonded to the carbon atom at the α-position in the explanation of the α-substituted acrylic acid ester. The same groups can be mentioned, and an alkyl group having 1 to 5 carbon atoms is preferred. Specifically, linear or branched alkyl groups are preferred. More specific examples 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, and a methyl group or an ethyl group is More preferred, and a methyl group is particularly preferred.

In the formula (a1-r-1), examples of the hydrocarbon group for Ra' ³ include linear or branched alkyl groups and cyclic hydrocarbon groups.
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 methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group and the like. 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 chain alkyl group preferably has 3 to 10 carbon atoms, more preferably 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, with an isopropyl group being preferred.

When Ra' ³ is a cyclic hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group.
As the monocyclic aliphatic hydrocarbon group, a group obtained by removing one hydrogen atom from a monocycloalkane is preferable. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclopentane and cyclohexane.
The aliphatic hydrocarbon group which is a polycyclic group is preferably a group obtained by removing one hydrogen atom from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically includes adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.

When the cyclic hydrocarbon group for Ra' ³ is an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring.
This 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 aromatic ring preferably has 5 to 30 carbon atoms, more preferably 5 to 20 carbon atoms, still 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; mentioned. The heteroatom in the aromatic heterocycle includes oxygen atom, sulfur atom, nitrogen atom and the like. Specific examples of aromatic heterocycles include pyridine rings and thiophene rings.
Specifically, the aromatic hydrocarbon group for Ra' ³ is a group obtained by removing one hydrogen atom from the aromatic hydrocarbon ring or aromatic heterocyclic ring (aryl group or heteroaryl group); A group obtained by removing one hydrogen atom from an aromatic compound containing (e.g., biphenyl, fluorene, etc.); phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, arylalkyl group such as 2-naphthylethyl group) and the like. The number of carbon atoms in the alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocyclic ring is preferably 1 to 4, more preferably 1 to 2 carbon atoms, and particularly 1 carbon atom. preferable.

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

- Tertiary alkyl ester type acid dissociable group:
Among the above polar groups, the acid-dissociable group protecting the carboxy group includes, for example, an acid-dissociable group represented by the following general formula (a1-r-2).
Among the acid-dissociable groups represented by the following formula (a1-r-2), those composed of alkyl groups may hereinafter be referred to as "tertiary alkyl ester-type acid-dissociable groups" for convenience. .

［式中、Ｒａ’^４～Ｒａ’^６はそれぞれ炭化水素基であって、Ｒａ’^５、Ｒａ’^６は互いに結合して環を形成してもよい。］

[In the formula, each of Ra' ⁴ to Ra' ⁶ is a hydrocarbon group, and Ra' ⁵ and Ra' ⁶ may combine with each other to form a ring. ]

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

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

[In the formula, Ra′ ¹⁰ is an alkyl group having 1 to 10 carbon atoms. Ra' ¹¹ is a group that forms an aliphatic cyclic group together with the carbon atom to which Ra' ¹⁰ is attached. Ra' ¹² to Ra' ¹⁴ each independently represent a hydrocarbon group. ]

In formula (a1-r2-1), the alkyl group having 1 to 10 carbon atoms for Ra' ¹⁰ is the linear or branched alkyl group for Ra' ³ in formula (a1-r-1). groups are preferred. In formula (a1-r2-1), the aliphatic cyclic group that ^Ra'11 forms together with the carbon atom to which ^Ra'10 is bonded is a monocyclic group for ^Ra'3 in formula (a1-r-1) or The groups mentioned as polycyclic aliphatic hydrocarbon groups are preferred.

In formula (a1-r2-2), Ra' ¹² and Ra' ¹⁴ are preferably each independently an alkyl group having 1 to 10 carbon atoms, and the alkyl group is Ra in formula (a1-r-1). The groups exemplified as the linear or branched alkyl group of ' ³ are more preferable, the linear alkyl group having 1 to 5 carbon atoms is more preferable, and the methyl group or the ethyl group is particularly preferable.
In formula (a1-r2-2), Ra' ¹³ is a linear or branched alkyl group or monocyclic group exemplified as the hydrocarbon group for Ra' ³ in formula (a1-r-1) or an aliphatic hydrocarbon group which is a polycyclic group. Among these, Ra' ¹³ is more preferably a linear or branched alkyl group exemplified as the hydrocarbon group for Ra' ³ .

Specific examples of the group represented by the formula (a1-r2-1) are shown below. * indicates a bond (the same applies hereinafter).

Specific examples of the group represented by the formula (a1-r2-2) are shown below.

- Tertiary alkyloxycarbonyl acid dissociable group:
Among the polar groups, the acid-dissociable group that protects the hydroxyl group includes, for example, an acid-dissociable group represented by the following general formula (a1-r-3) (hereinafter referred to as a tertiary alkyloxycarbonyl acid-dissociable group ) can be mentioned.

［式中、Ｒａ’^７～Ｒａ’^９はそれぞれアルキル基である。］

[In the formula, each of Ra' ⁷ to Ra' ⁹ is an alkyl group. ]

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

Among the above, as an acid-labile group for a base resin for a chemically amplified resist, a combined effect (resolution, dimensional uniformity (CDU) within the support surface (shot), etc.) can be obtained in combination with the component (B). tertiary alkyl ester-type acid-dissociable group is preferable, and an acid-dissociable group represented by formula (a1-r-2) is more preferable, and represented by general formula (a1-r2-2). is more preferred.
Among the groups represented by the general formula (a1-r2-2), the groups represented by the above formula (r-pr-c1), formula (r-pr-c2) or formula (r-pr-c3) is preferred.

As the structural unit (a1), a structural unit derived from an acrylic ester in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent, a structural unit derived from acrylamide, hydroxystyrene or hydroxy - of structural units derived from vinyl benzoic acid or vinyl benzoic acid derivatives, wherein at least part of the hydrogen atoms in the hydroxyl groups of structural units derived from styrene derivatives are protected by substituents containing the acid-decomposable groups Structural units in which at least part of the hydrogen atoms in C(=O)--OH are protected by a substituent containing the acid-decomposable group are exemplified.

As the structural unit (a1), among the above, a structural unit derived from an acrylic ester in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent is preferable.
Preferred specific examples of such a structural unit (a1) include structural units represented by the following general formula (a1-1) or (a1-2).

［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。Ｖａ^１はエーテル結合を有していてもよい２価の炭化水素基である。ｎ_ａ１は０～２の整数である。Ｒａ^１は上記の式（ａ１－ｒ－１）又は（ａ１－ｒ－２）で表される酸解離性基である。Ｗａ^１はｎ_ａ２＋１価の炭化水素基である。ｎ_ａ２は１～３の整数である。Ｒａ^２は上記の式（ａ１－ｒ－１）又は（ａ１－ｒ－３）で表される酸解離性基である。］

[In the formula, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. Va ¹ is a divalent hydrocarbon group optionally having an ether bond. n _a1 is an integer of 0-2. Ra ¹ is an acid dissociable group represented by the above formula (a1-r-1) or (a1-r-2). Wa ¹ is an n _a2 + monovalent hydrocarbon group. n _a2 is an integer of 1-3. Ra ² is an acid dissociable group represented by the above formula (a1-r-1) or (a1-r-3). ]

In the above formula (a1-1), the alkyl group having 1 to 5 carbon atoms in R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specifically, a methyl group or an ethyl group. , propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like. A halogenated alkyl group having 1 to 5 carbon atoms 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. The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and 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 most preferably a hydrogen atom or a methyl group in terms of industrial availability.

In the above formula (a1-1), the divalent hydrocarbon group optionally having an ether bond of Va ¹ has an ether bond as a substituent of Ya ^x1 in the above formula (a10-1). is the same as in the case of a divalent hydrocarbon group which may be

In the formula (a1-2), the n _a2 +1 valent hydrocarbon group in Wa ¹ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity, and may be saturated or unsaturated, and usually preferably saturated. As the aliphatic hydrocarbon group, a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, or a linear or branched aliphatic hydrocarbon group Examples thereof include a group combined with an aliphatic hydrocarbon group containing a ring in the structure.
The n _a2 +1 valence is preferably divalent to tetravalent, more preferably divalent or trivalent.

Specific examples of the structural unit represented by formula (a1-1) are shown below.
In each formula below, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

Specific examples of the structural unit represented by formula (a1-2) are shown below.

The structural unit (a1) contained in the component (A1) may be one type or two or more types.
The ratio of the structural unit (a1) in the component (A1) is preferably 5 to 90 mol%, preferably 10 to 70 mol%, relative to the total (100 mol%) of all structural units constituting the component (A1). is more preferred, and 15 to 50 mol % is particularly preferred.
By setting the proportion of the structural unit (a1) to be equal to or higher than the lower limit of the preferred range, the contrast between the exposed and unexposed areas of the resist film is further enhanced, and the resolution is improved. On the other hand, by making it equal to or less than the upper limit of the preferred range, it becomes easier to balance with other structural units.

≪Other structural units≫
The component (A1) may have structural units other than the structural unit (a10) and the structural unit (a1) described above.
Other structural units include, for example, a structural unit (a2) containing a lactone-containing cyclic group, a —SO ₂ —-containing cyclic group, or a carbonate-containing cyclic group (provided that the structural unit (a10) or the structural unit (a1) excluding those applicable), a structural unit (a4) containing an acid-nondissociable aliphatic cyclic group, a structural unit derived from styrene, a structural unit derived from a styrene derivative (provided that the structural unit (a10) (excluding those applicable), structural units containing a polar group-containing aliphatic hydrocarbon group (excluding any of the structural units described above), and the like.

・Constituent unit (a2)
Structural unit (a2) is a structural unit containing a lactone-containing cyclic group, —SO ₂ —-containing cyclic group or carbonate-containing cyclic group (provided that the structural unit (a10) or structural unit (a1) corresponds to excluding).
The lactone-containing cyclic group, —SO ₂ —-containing cyclic group, or carbonate-containing cyclic group of the structural unit (a2) improves the adhesion of the resist film to the substrate when the component (A1) is used to form the resist film. is effective in increasing In addition, since the component (A1) has the structural unit (a2), the solubility of the resist film in an alkaline developer increases during development in the alkaline development process.

A “lactone-containing cyclic group” refers to a cyclic group containing a ring (lactone ring) containing —O—C(═O)— in its ring skeleton. A lactone ring is counted as the first ring, and a group containing only a lactone ring is called a monocyclic group, and a group containing other ring structures is called a polycyclic group regardless of the structure. A lactone-containing cyclic group may be a monocyclic group or a polycyclic group.
Any lactone-containing cyclic group in the structural unit (a2) can be used without particular limitation. Specific examples include groups represented by the following general formulas (a2-r-1) to (a2-r-7).

［式中、Ｒａ’^２１はそれぞれ独立に水素原子、アルキル基、アルコキシ基、ハロゲン原子、ハロゲン化アルキル基、水酸基、－ＣＯＯＲ”、－ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基又はシアノ基である。Ｒ”は水素原子、アルキル基、ラクトン含有環式基、カーボネート含有環式基、又は－ＳＯ_２－含有環式基である。Ａ”は酸素原子（－Ｏ－）もしくは硫黄原子（－Ｓ－）を含んでいてもよい炭素数１～５のアルキレン基、酸素原子または硫黄原子である。ｎ’は０～２の整数であり、ｍ’は０又は１である。］

[In the formula, each Ra' ²¹ is independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR'', -OC(=O)R'', a hydroxyalkyl group or a cyano group; be. R″ is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a —SO ₂ —-containing cyclic group. A″ is an oxygen atom (—O—) or a sulfur atom (—S— ), an alkylene group having 1 to 5 carbon atoms, an oxygen atom or a sulfur atom. n' is an integer of 0 to 2, and m' is 0 or 1; ]

In the general formulas (a2-r-1) to (a2-r-7), the alkyl group for Ra' ²¹ is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specific examples include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and hexyl group. Among these, a methyl group or an ethyl group is preferred, and a methyl group is particularly preferred.
As the alkoxy group for Ra' ²¹ , an alkoxy group having 1 to 6 carbon atoms is preferable. The alkoxy group is preferably linear or branched. Specific examples include groups in which the alkyl group exemplified as the alkyl group for Ra' ²¹ and an oxygen atom (--O--) are linked.
The halogen atom for Ra' ²¹ includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferred.
Examples of the halogenated alkyl group for Ra' ²¹ include groups in which some or all of the hydrogen atoms of the alkyl group for Ra' ²¹ are substituted with the halogen atoms. As the halogenated alkyl group, a fluorinated alkyl group is preferable, and a perfluoroalkyl group is particularly preferable.

In -COOR'' and -OC(=O)R'' in Ra' ²¹ , R'' is either a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a -SO ₂ -containing cyclic group. is.
The alkyl group for R″ may be linear, branched or cyclic, and preferably has 1 to 15 carbon atoms.
When R″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group or an ethyl group. preferable.
When R″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. or groups obtained by removing one or more hydrogen atoms from monocycloalkanes which may or may not be substituted with fluorinated alkyl groups; polycycloalkanes such as bicycloalkanes, tricycloalkanes and tetracycloalkanes Examples include groups obtained by removing one or more hydrogen atoms from, etc. More specifically, groups obtained by removing one or more hydrogen atoms from monocycloalkanes such as cyclopentane and cyclohexane; Examples include groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as cyclodecane and tetracyclododecane.
Examples of the lactone-containing cyclic group for R″ include the same groups as those represented by the general formulas (a2-r-1) to (a2-r-7).
The carbonate-containing cyclic group in R" is the same as the carbonate-containing cyclic group described later, and specifically groups represented by general formulas (ax3-r-1) to (ax3-r-3), respectively. is mentioned.
The —SO ₂ -containing cyclic group in R″ is the same as the —SO ₂ -containing cyclic group described later, and specifically, general formulas (a5-r-1) to (a5-r-4) The group represented respectively by is mentioned.
The hydroxyalkyl group for Ra' ²¹ preferably has 1 to 6 carbon atoms, and specific examples include groups in which at least one hydrogen atom of the alkyl group for Ra' ²¹ is substituted with a hydroxyl group. .

In the general formulas (a2-r-2), (a2-r-3) and (a2-r-5), the alkylene group having 1 to 5 carbon atoms in A″ is a linear or branched An alkylene group is preferred, and includes a methylene group, an ethylene group, an n-propylene group, an isopropylene group, etc. When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include the terminal of the alkylene group or the carbon Groups having -O- or -S- interposed between atoms, such as -O-CH ₂ -, -CH ₂ -O-CH ₂ -, -S-CH ₂ -, -CH ₂ -S-CH _A ″ is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.

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

The term “—SO ₂ —containing cyclic group” refers to a cyclic group containing a ring containing —SO ₂ — in its ring skeleton, and specifically, the sulfur atom (S) in —SO ₂ — is A cyclic group that forms part of the ring skeleton of a cyclic group. A ring containing —SO ₂ — in its ring skeleton is counted as the first ring, and if it contains only this ring, it is a monocyclic group, and if it has another ring structure, it is a polycyclic group regardless of its structure. called. The —SO ₂ —containing cyclic group may be a monocyclic group or a polycyclic group.
A —SO ₂ —-containing cyclic group is particularly a cyclic group containing —O—SO ₂ — in its ring skeleton, ie, —O—S— in —O—SO ₂ — forms part of the ring skeleton. Preferred are cyclic groups containing a forming sultone ring.
More specific examples of the —SO ₂ —containing cyclic group include groups represented by general formulas (a5-r-1) to (a5-r-4) below.

［式中、Ｒａ’^５１はそれぞれ独立に水素原子、アルキル基、アルコキシ基、ハロゲン原子、ハロゲン化アルキル基、水酸基、－ＣＯＯＲ”、－ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基又はシアノ基である。Ｒ”は水素原子、アルキル基、ラクトン含有環式基、カーボネート含有環式基、又は－ＳＯ_２－含有環式基である。Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１～５のアルキレン基、酸素原子又は硫黄原子である。ｎ’は０～２の整数である。］

[In the formula, each Ra' ⁵¹ is independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR'', -OC(=O)R'', a hydroxyalkyl group or a cyano group; be. R″ is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a —SO ₂ —-containing cyclic group. A″ has 1 carbon atom which may contain an oxygen atom or a sulfur atom ∼5 alkylene groups, an oxygen atom or a sulfur atom. n' is an integer of 0-2. ]

In the general formulas (a5-r-1) to (a5-r-2), A″ is the general formulas (a2-r-2), (a2-r-3), (a2-r-5) It is the same as A” inside.
The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, -COOR'', -OC(=O)R'' and hydroxyalkyl group in Ra' ⁵¹ are represented by the general formulas (a2-r-1) to ( Examples are the same as those mentioned in the description of Ra' ²¹ in a2-r-7).
Specific examples of groups represented by general formulas (a5-r-1) to (a5-r-4) are shown below. "Ac" in the formula represents an acetyl group.

A “carbonate-containing cyclic group” refers to a cyclic group containing a ring (carbonate ring) containing —O—C(═O)—O— in its ring skeleton. The carbonate ring is counted as the first ring, and the group containing only the carbonate ring is called a monocyclic group, and the group containing other ring structures is called a polycyclic group regardless of the structure. A carbonate-containing cyclic group may be a monocyclic group or a polycyclic group.
Any carbonate ring-containing cyclic group can be used without particular limitation. Specific examples include groups represented by general formulas (ax3-r-1) to (ax3-r-3) below.

［式中、Ｒａ’^ｘ３１はそれぞれ独立に水素原子、アルキル基、アルコキシ基、ハロゲン原子、ハロゲン化アルキル基、水酸基、－ＣＯＯＲ”、－ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基又はシアノ基である。Ｒ”は水素原子、アルキル基、ラクトン含有環式基、カーボネート含有環式基、又は－ＳＯ_２－含有環式基である。Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１～５のアルキレン基、酸素原子又は硫黄原子である。ｐ’は０～３の整数であり、ｑ’は０又は１である。］

[Wherein, each ^Ra'x31 is independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR'', -OC(=O)R'', a hydroxyalkyl group or a cyano group; be. R″ is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or a —SO ₂ —-containing cyclic group. A″ has 1 carbon atom which may contain an oxygen atom or a sulfur atom ∼5 alkylene groups, an oxygen atom or a sulfur atom. p' is an integer of 0 to 3, and q' is 0 or 1; ]

In the general formulas (ax3-r-2) to (ax3-r-3), A″ is the general formulas (a2-r-2), (a2-r-3), (a2-r-5) It is the same as A” inside.
The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, -COOR'', -OC(=O)R'', and hydroxyalkyl group in Ra' ³¹ are represented by the general formulas (a2-r-1) to ( Examples are the same as those mentioned in the description of Ra' ²¹ in a2-r-7).

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

As the structural unit (a2), a structural unit derived from an acrylic ester in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent is particularly preferred.
Such a structural unit (a2) is preferably a structural unit represented by general formula (a2-1) 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^２１は単結合又は２価の連結基である。Ｌａ^２１は－Ｏ－、－ＣＯＯ－、－ＣＯＮ（Ｒ’）－、－ＯＣＯ－、－ＣＯＮＨＣＯ－又は－ＣＯＮＨＣＳ－であり、Ｒ’は水素原子又はメチル基を示す。但し、Ｌａ^２１が－Ｏ－の場合、Ｙａ^２１は－ＣＯ－にはならない。Ｒａ^２１はラクトン含有環式基、カーボネート含有環式基、又は－ＳＯ_２－含有環式基である。］

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

In formula (a2-1), R is the same as defined above.
The divalent linking group for Ya ²¹ includes the same divalent linking groups for Ya ^x1 in general formula (a10-1) described above. Among these, Ya ²¹ is a single bond, an ester bond [-C(=O)-O-], an ether bond (-O-), a linear or branched alkylene group, or a combination thereof. is preferred.

In formula (a2-1) above, Ra ²¹ is a lactone-containing cyclic group, —SO ₂ —-containing cyclic group or carbonate-containing cyclic group.
The lactone-containing cyclic group, —SO ₂ —-containing cyclic group, and carbonate-containing cyclic group for Ra ²¹ are represented by the above-described general formulas (a2-r-1) to (a2-r-7), respectively. Groups represented by general formulas (a5-r-1) to (a5-r-4), respectively represented by general formulas (ax3-r-1) to (ax3-r-3) groups are preferred.
Among them, a lactone-containing cyclic group or a —SO ₂ —-containing cyclic group is preferable, and the general formula (a2-r-1), (a2-r-2), (a2-r-6) or (a5-r -1) are more preferred. Specifically, the chemical formulas (r-lc-1-1) to (r-lc-1-7), (r-lc-2-1) to (r-lc-2-18), (r- Any group represented by lc-6-1), (r-sl-1-1) and (r-sl-1-18) is more preferred.

The structural unit (a2) contained in the component (A1) may be one type or two or more types.
When the component (A1) has the structural unit (a2), the ratio of the structural unit (a2) in the component (A1) is based on the total (100 mol%) of all the structural units constituting the component (A1). , preferably 1 to 40 mol %, more preferably 2 to 20 mol %, even more preferably 5 to 10 mol %.
By setting the proportion of the structural unit (a2) to be equal to or higher than the lower limit of the above preferred range, the effect of containing the structural unit (a2) can be sufficiently obtained. On the other hand, when the amount is equal to or less than the upper limit of the preferable range, it becomes easier to balance with other structural units, and various lithography properties and pattern shapes are improved.

・Constituent unit (a4)
The structural unit (a4) is a structural unit containing an acid non-dissociable aliphatic cyclic group.
By including the structural unit (a4) in the component (A1), the dry etching resistance of the formed resist pattern is improved. Moreover, the hydrophobicity of the component (A) is increased. Improvement in hydrophobicity contributes to improvement in resolution, resist pattern shape, etc., particularly in the case of resist pattern formation by a solvent development process.
The "acid-non-dissociable cyclic group" in the structural unit (a4) is such that when acid is generated in the resist composition by exposure (for example, when acid is generated from component (B) described later), the acid is a cyclic group that remains in the structural unit as it is without being dissociated even when is acted on.
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing an acid-nondissociable aliphatic cyclic group is preferred. As the aliphatic cyclic group, a large number of conventionally known ones for use in resin components of resist compositions for ArF excimer lasers, KrF excimer lasers (preferably for ArF excimer lasers), etc. can be used. is.
In particular, at least one group selected from the group consisting of a tricyclodecyl group, adamantyl group, tetracyclododecyl group, isobornyl group and norbornyl group is preferable from the viewpoint of industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include structural units represented by general formulas (a4-1) to (a4-7) below.

［式中、Ｒ^αは前記と同じである。］

[In the formula, R ^α is the same as described above. ]

The structural unit (a4) contained in the component (A1) may be one type or two or more types.
When the component (A1) has the structural unit (a4), the ratio of the structural unit (a4) in the component (A1) is based on the total (100 mol%) of all the structural units constituting the component (A1). , preferably 1 to 30 mol %, more preferably 3 to 20 mol %.
By setting the proportion of the structural unit (a4) to be equal to or higher than the lower limit of the preferred range, the effect of containing the structural unit (a4) can be sufficiently obtained. On the other hand, by making it equal to or less than the upper limit of the preferred range, it becomes easier to balance with other structural units.

Structural units derived from styrene When component (A1) has structural units derived from styrene, the ratio of structural units derived from styrene in component (A1) is It is preferably 1 to 30 mol %, more preferably 3 to 20 mol %, relative to the total (100 mol %) of the structural units.

In the resist composition of the embodiment, component (A) contains a polymer compound (A1) having a structural unit (a10) and a structural unit (a1).
As the component (A1), a polymer compound having a repeating structure of the structural unit (a10) and the structural unit (a1) is preferable. A polymer compound having a repeating structure with a structural unit is particularly preferred.

The weight average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography (GPC)) is preferably 5,000 to 20,000, more preferably 7,000 to 15,000, and even more preferably 8,000 to 13,000.
When the Mw of the component (A1) is equal to or less than the upper limit of the preferred range, it becomes easier to prevent the viscosity of the resist composition from becoming too high, and the coatability of the resist composition onto a support is further improved. In addition, it becomes easy to have sufficient solubility in a resist solvent for use as a resist, and it becomes easy to improve sensitivity. On the other hand, when it is at least the lower limit of the preferred range, a thick resist film can be easily formed. In addition, the dry etching resistance and the cross-sectional shape of the resist pattern are improved.

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

The component (A1) contained in the resist composition may be used alone or in combination of two or more.
The ratio of component (A1) in component (A) is preferably 25% by mass or more, more preferably 50% by mass or more, still more preferably 75% by mass or more, and 100% by mass, relative to the total mass of component (A). may be When the ratio of the component (A1) is at least the lower limit of the above preferable range, the resist pattern has high sensitivity, resolution, uniformity of dimensions within the support surface (shot) (CDU) and other lithography properties. are easier to form.

In the resist composition of the embodiment, the concentration of the polymer compound (A1) is preferably 15 to 50% by mass, and 25 to 45% by mass with respect to the total amount (100% by mass) of the resist composition. More preferably, 30 to 40% by mass is even more preferable.
When the concentration of the component (A1) in the resist composition is at least the lower limit of the preferred range, a thick resist film is easily formed. It becomes easy to suppress the viscosity of the resist composition from becoming too high.

In the resist composition of this embodiment, the component (A) may be used alone or in combination of two or more.
The content of component (A) in the resist composition of the present embodiment may be adjusted according to the resist film thickness to be formed.

<(B) Component>
The resist composition of the present embodiment further contains an acid generator component (B) (hereinafter referred to as "component (B)") in addition to component (A).
The component (B) contains a specific acid generator (B1), that is, an acid generator (B1) represented by the general formula (b1) described later (hereinafter also referred to as "(B1) component"). . By including the component (B1), foaming during high-temperature baking is suppressed in resist pattern formation. In addition, when forming a resist pattern, good sensitivity can be easily maintained, and lithography properties (dimensional uniformity, etc.) are improved.

- Component (B1) Component (B1) is an acid generator represented by the following general formula (b1).

［式中、Ｒ^２０１１、Ｒ^２０２１及びＲ^２０３１は、それぞれ独立に、置換基を有していてもよいアリール基を表す。Ｒ^２０１１、Ｒ^２０２１及びＲ^２０３１のうち２つ以上が相互に結合して、式中のイオウ原子と共に環を形成してもよい。Ｘ^－は、対アニオンを表す。］

[In the formula, R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ each independently represent an optionally substituted aryl group. Two or more of R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ may combine with each other to form a ring together with the sulfur atom in the formula. X ⁻ represents a counter anion. ]

In formula (b1), R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ each independently represent an aryl group which may have a substituent.
The aryl group for R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ includes unsubstituted aryl groups having 6 to 20 carbon atoms, preferably phenyl group and naphthyl group.

Examples of substituents that the aryl group in R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ 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 the following Examples thereof include groups represented by general formulas (ca-r-1) to (ca-r-7).
The alkyl group as a substituent here is preferably an alkyl group having 1 to 5 carbon atoms, preferably a linear or branched alkyl group.
The halogenated alkyl group as the substituent here is preferably a halogenated alkyl group having 1 to 5 carbon atoms, preferably a linear or branched halogenated alkyl group.
The aryl group as a substituent here includes an aryl group having 6 to 20 carbon atoms, preferably a phenyl group or a naphthyl group.

［式中、Ｒ’^２０１は、それぞれ独立に、水素原子、置換基を有していてもよい環式基、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, each R′ ²⁰¹ is independently a hydrogen atom, an optionally substituted cyclic group, an optionally substituted chain alkyl group, or a substituted is a chain alkenyl group that may be ]

In the above formulas (ca-r-1) to (ca-r-7), R' ²⁰¹ is each independently a hydrogen atom, an optionally substituted cyclic group, a substituent a chain alkyl group which may be substituted or a chain alkenyl group which may have a substituent.

Cyclic group optionally having a substituent:
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. An aliphatic hydrocarbon group means a hydrocarbon group without aromaticity. Also, the aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

The aromatic hydrocarbon group for R' ²⁰¹ 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, and particularly preferably 6 to 15 carbon atoms. Numbers 6-10 are most preferred. However, the number of carbon atoms does not include the number of carbon atoms in the substituent.
Specific examples of the aromatic ring of the aromatic hydrocarbon group in R′ ²⁰¹ include benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, or those in which some of the carbon atoms constituting the aromatic ring are substituted with heteroatoms. and aromatic heterocycles. The heteroatom in the aromatic heterocycle includes oxygen atom, sulfur atom, nitrogen atom and the like.
Specific examples of the aromatic hydrocarbon group for R′ ²⁰¹ include a group obtained by removing one hydrogen atom from the aromatic ring (aryl group: for example, a phenyl group, a naphthyl group, etc.), and one of the hydrogen atoms in the aromatic ring is alkylene. groups substituted with groups (for example, arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc.), and the like. 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' ²⁰¹ includes an aliphatic hydrocarbon group containing a ring in its structure.
The aliphatic hydrocarbon group containing a ring in this structure includes an alicyclic hydrocarbon group (a group obtained by removing one hydrogen atom from an aliphatic hydrocarbon ring), and an alicyclic hydrocarbon group that is linear or branched. Examples thereof include a group bonded to the end of a chain aliphatic hydrocarbon group, and a group in which an alicyclic hydrocarbon group intervenes in the middle of a linear or branched aliphatic hydrocarbon group.
The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, more preferably 3 to 12 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 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 polycycloalkanes include polycycloalkanes having a bridged ring system polycyclic skeleton such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane; condensed ring systems such as cyclic groups having a steroid skeleton; Polycycloalkanes having a polycyclic skeleton of are more preferred.

Among them, the cyclic aliphatic hydrocarbon group for R′ ²⁰¹ is preferably a group obtained by removing one or more hydrogen atoms from monocycloalkane or polycycloalkane, and a group obtained by removing one hydrogen atom from polycycloalkane. More preferred are an adamantyl group and a norbornyl group, and most preferred is an adamantyl group.

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, and Numbers 1 to 4 are more preferred, and carbon numbers 1 to 3 are most preferred.
As the straight-chain aliphatic hydrocarbon group, a straight-chain alkylene group is preferable, and specifically, a methylene group [-CH ₂ -], an ethylene group [-(CH ₂ ) ₂ -], a trimethylene group [ -(CH ₂ ) ₃ -], tetramethylene group [-(CH ₂ ) ₄ -], pentamethylene group [-(CH ₂ ) ₅ -] and the like.
The branched chain aliphatic hydrocarbon group is preferably a branched chain alkylene group, and specifically, -CH(CH ₃ )-, -CH(CH ₂ CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CH ₃ )(CH ₂ CH ₃ )-, -C(CH ₃ )(CH ₂ CH ₂ CH ₃ )-, -C(CH ₂ CH ₃ ) ₂ - and other alkylmethylene groups; CH(CH ₃ )CH ₂ -, -CH(CH ₃ )CH(CH ₃ )-, -C(CH ₃ ) ₂ CH ₂ -, -CH(CH ₂ CH ₃ )CH ₂ -, -C(CH ₂ Alkylethylene groups such as CH ₃ ) ₂ --CH ₂ --; Alkyl trimethylene groups such as --CH(CH ₃ )CH ₂ CH ₂ -- and --CH ₂ CH(CH ₃ )CH ₂ --; --CH(CH ₃ ) Examples thereof include alkylalkylene groups such as alkyltetramethylene groups such as CH ₂ CH ₂ CH ₂ — and —CH ₂ CH(CH ₃ )CH ₂ CH ₂ —. As the alkyl group in the alkylalkylene group, a linear alkyl group having 1 to 5 carbon atoms is preferable.

In addition, the cyclic hydrocarbon group for R' ²⁰¹ may contain a heteroatom such as a heterocyclic ring. Specifically, the lactone-containing cyclic groups represented by the general formulas (a2-r-1) to (a2-r-7), the general formulas (a5-r-1) to (a5-r- 4), and _heterocyclic groups represented by the following chemical formulas (r-hr-1) to (r-hr-16).

Further, examples of the cyclic group which may have a substituent include those similar to the acid dissociable group represented by the above formula (a1-r-2).

Examples of substituents on the cyclic group of R' ²⁰¹ include alkyl groups, alkoxy groups, halogen atoms, halogenated alkyl groups, hydroxyl groups, carbonyl groups, and nitro groups.
The alkyl group as a substituent is preferably an alkyl group having 1 to 5 carbon atoms, more 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 and a tert-butoxy group. Most preferred is the ethoxy group.
A halogen atom as a substituent includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.
Halogenated alkyl groups as substituents include alkyl groups having 1 to 5 carbon atoms, such as methyl group, ethyl group, propyl group, n-butyl group, tert-butyl group, etc., wherein some or all of the hydrogen atoms are the above-mentioned Groups substituted with halogen atoms are included.
A carbonyl group as a substituent is a group that substitutes a methylene group ( _--CH.sub.2-- ) constituting a cyclic hydrocarbon group.

A chain alkyl group optionally having a substituent:
The chain alkyl group for R' ²⁰¹ may be linear or branched.
The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decanyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, henicosyl group, docosyl group and the like.
The branched-chain alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.
Examples of the chain alkyl group which may have a substituent include those similar to the acid dissociable group represented by the above formula (a1-r-2).

A chain alkenyl group optionally having a substituent:
The chain alkenyl group for R' ²⁰¹ may be linear or branched, preferably having 2 to 10 carbon atoms, more preferably 2 to 5 carbon atoms, and 2 to 4 carbon atoms. is more preferred, with 3 carbon atoms being particularly preferred. Examples of linear alkenyl groups include vinyl groups, propenyl groups (allyl groups), and butynyl groups. Examples of branched alkenyl groups include 1-methylvinyl group, 2-methylvinyl group, 1-methylpropenyl group, 2-methylpropenyl group and the like.
Among the above, the chain alkenyl group is preferably a linear alkenyl group, more preferably a vinyl group or a propenyl group, and particularly preferably a vinyl group.

Examples of substituents on the linear alkyl group or alkenyl group for ^R'201 include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group, an amino group, and a cyclic group for ^R'201 . etc.

Among the above, R' ²⁰¹ is preferably an optionally substituted cyclic group, more preferably an optionally substituted cyclic hydrocarbon group. More specifically, a group obtained by removing one or more hydrogen atoms from a phenyl group, a naphthyl group, or a polycycloalkane; represented by the general formulas (a2-r-1) to (a2-r-7) Lactone-containing cyclic group; --SO ₂ --containing cyclic groups represented by the general formulas (a5-r-1) to (a5-r-4) are preferred. Among them, R′ ²⁰¹ is more preferably a group obtained by removing one or more hydrogen atoms from polycycloalkane, which may have a substituent.

In the component (B1) contained in the resist composition of the embodiment, at least one of R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ in the general formula (b1) is preferably an aryl group having a substituent. When at least one of R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ is an aryl group having a substituent, foaming during high-temperature baking is easily suppressed, and solubility in organic solvents is enhanced, resulting in development. Precipitation of time becomes difficult to occur. In addition, the process margin during pattern formation tends to increase, and for example, the depth of focus (DOF) characteristics tend to improve.
In this case, the substituents of the aryl group in R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and the above general formula ( It is preferably one or more selected from the group consisting of groups represented by ca-r-1) to (ca-r-7).

Two or more of R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ may be combined to form a ring together with the sulfur atom in the formula.
When forming a ring in this way, a heteroatom such as a sulfur atom, an oxygen atom, a nitrogen atom, a carbonyl group, -SO-, -SO ₂ -, -SO ₃ -, -COO-, -CONH- or -N (R _N )—(R _N is an alkyl group having 1 to 5 carbon atoms) or the like.
As the ring to be formed, one ring containing a sulfur atom in the formula in its ring skeleton is preferably a 3- to 10-membered ring including a sulfur atom, particularly a 5- to 7-membered ring. preferable. 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 phenoxathiine ring, and a tetrahydro A thiophenium ring, a tetrahydrothiopyranium ring, and the like are included.

Specific examples of suitable cations in the acid generator represented by the general formula (b1) include cations represented by the following chemical formulas (ca-1-1) to (ca-1-55). be done.

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

[In the formula, g1, g2 and g3 represent the number of repetitions, g1 is an integer of 1 to 5, g2 is an integer of 0 to 20, and g3 is an integer of 0 to 20. ]

In the formula (b1), X ^- represents a counter anion.
X 1 ⁻ is not particularly limited, and an anion known as an anion portion of an acid generator component for a resist composition can be appropriately used.
For example, X ^- includes an anion represented by the following general formula (b1-a1), an anion represented by the general formula (b1-a2) or an anion represented by the general formula (b1-a3). .

［式中、Ｒ^１０１、Ｒ^１０４～Ｒ^１０８はそれぞれ独立に置換基を有していてもよい環式基、置換基を有していてもよい鎖状のアルキル基、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。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。］

[In the formula, R ¹⁰¹ , R ¹⁰⁴ to R ¹⁰⁸ are each independently an optionally substituted cyclic group, an optionally substituted chain alkyl group, or a substituted is a chain alkenyl group that may be R ¹⁰⁴ and R ¹⁰⁵ may combine with 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 divalent linking group containing a single bond or 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 —. ]

- an anion represented by the general formula (b1-a1) In the formula (b1-a1), R ¹⁰¹ is a cyclic group optionally having a substituent, a chain optionally having a substituent an alkyl group or an optionally substituted chain alkenyl group, each of which is the same as ^R'201 in the above formulas (ca-r-1) to (ca-r-7); mentioned.
Among the above, R ¹⁰¹ is preferably an optionally substituted cyclic group, more preferably an optionally substituted cyclic hydrocarbon group. More specifically, a group obtained by removing one or more hydrogen atoms from a phenyl group, a naphthyl group, or a polycycloalkane; represented by the general formulas (a2-r-1) to (a2-r-7) Lactone-containing cyclic groups: —SO ₂ —-containing cyclic groups represented by the general formulas (a5-r-1) to (a5-r-4) are preferred.

In formula (b1-a1), Y ¹⁰¹ is a divalent linking group containing a single bond or an oxygen atom.
When Y ¹⁰¹ is a divalent linking group containing an oxygen atom, said Y ¹⁰¹ may contain an atom other than an oxygen atom. Atoms other than an oxygen atom include, for example, a carbon atom, a hydrogen atom, a sulfur atom, a nitrogen atom, and the like.
The divalent linking group containing an oxygen atom includes, for example, an oxygen atom (ether bond: -O-), an ester bond (-C(=O)-O-), an oxycarbonyl group (-OC(=O )-), amide bond (-C(=O)-NH-), carbonyl group (-C(=O)-), carbonate bond (-OC(=O)-O-), etc. and a combination of the non-hydrocarbon oxygen atom-containing linking group and an alkylene group. A sulfonyl group ( _--SO.sub.2-- ) may be further linked to this combination. Such a divalent linking group containing an oxygen atom includes, for example, linking groups represented by the following general formulas (y-al-1) to (y-al-7).

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

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

The divalent saturated hydrocarbon group for V' ¹⁰² is preferably an alkylene group having 1 to 30 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, and an alkylene group having 1 to 5 carbon atoms. is more preferable.

The alkylene group for V' ¹⁰¹ and V' ¹⁰² may be either a linear alkylene group or a branched alkylene group, and is preferably a linear alkylene group.
Specific examples of the alkylene group for V' ¹⁰¹ and V' ¹⁰² include a methylene group [-CH 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 )-, -C(CH ₂ CH ₃ ) ₂ - and other alkylmethylene groups; ethylene groups [-CH ₂ CH ₂ -]; -CH(CH ₃ )CH ₂ -, -CH(CH ₃ )CH(CH ₃ )-, -C(CH ₃ ) ₂ CH ₂ -, -CH(CH ₂ CH ₃ ) Alkylethylene groups such as CH ₂ -; trimethylene group (n-propylene group) [-CH ₂ CH ₂ CH ₂ -]; -CH(CH ₃ )CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ ) Alkyltrimethylene groups such as CH ₂ -; Tetramethylene group [-CH ₂ CH ₂ CH ₂ CH ₂ -]; -CH(CH ₃ )CH ₂ CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ Alkyltetramethylene groups such as CH ₂ —; pentamethylene groups [—CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ —] and the like.
Further, part of the methylene groups in the alkylene group in ^V'101 or ^V'102 may be substituted with a divalent aliphatic cyclic group having 5 to 10 carbon atoms. The aliphatic cyclic group is a cyclic aliphatic hydrocarbon group ( ^monocyclic aliphatic hydrocarbon group, polycyclic aliphatic hydrocarbon group ) with one more hydrogen atom removed, and more preferably a cyclohexylene group, a 1,5-adamantylene group or a 2,6-adamantylene group.

Y ¹⁰¹ is preferably a divalent linking group containing an ester bond or a divalent linking group containing an ether bond, represented by the above formulas (y-al-1) to (y-al-5), respectively. Linking groups are more preferred.

In formula (b1-a1), V ¹⁰¹ is a single bond, an alkylene group or a fluorinated alkylene group. The alkylene group and fluorinated alkylene group for V ¹⁰¹ preferably have 1 to 4 carbon atoms. Examples of the fluorinated alkylene group for V ¹⁰¹ include groups in which some or all of the hydrogen atoms in the alkylene group for V ¹⁰¹ are substituted with fluorine atoms. Among them, V ¹⁰¹ is preferably a single bond or a fluorinated alkylene group having 1 to 4 carbon atoms.

In formula (b1-a1), 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 C 1-5 perfluoroalkyl group, more preferably a fluorine atom.

Specific examples of the anion moiety represented by the formula (b1-a1) include fluorinated alkylsulfonate anions such as trifluoromethanesulfonate anions and perfluorobutanesulfonate anions when Y ¹⁰¹ is a single bond. . When Y ¹⁰¹ is a divalent linking group containing an oxygen atom, anions represented by any of the following general formulas (an-1) to (an-3) can be mentioned.

［式中、Ｒ”^１０１は、置換基を有していてもよい脂肪族環式基、前記式（ｒ－ｈｒ－１）～（ｒ－ｈｒ－６）でそれぞれ表される基、又は置換基を有していてもよい鎖状のアルキル基である。Ｒ”^１０２は、置換基を有していてもよい脂肪族環式基、前記一般式（ａ２－ｒ－１）～（ａ２－ｒ－７）でそれぞれ表されるラクトン含有環式基、又は前記一般式（ａ５－ｒ－１）～（ａ５－ｒ－４）でそれぞれ表される－ＳＯ_２－含有環式基である。Ｒ”^１０３は、置換基を有していてもよい芳香族環式基、置換基を有していてもよい脂肪族環式基、又は置換基を有していてもよい鎖状のアルケニル基である。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又は１である。］

[Wherein, R″ ¹⁰¹ is an optionally substituted aliphatic cyclic group, a group represented by each of the above formulas (r-hr-1) to (r-hr-6), or a substituted is a chain alkyl group which may have a group. R″ ¹⁰² is an aliphatic cyclic group which may have a substituent; r-7), or —SO ₂ —containing cyclic groups represented by general formulas (a5-r-1) to (a5-r-4) above. R″ ¹⁰³ is an optionally substituted aromatic cyclic group, an optionally substituted aliphatic cyclic group, or an optionally substituted chain alkenyl group 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 optionally substituted aliphatic cyclic group of R″ ¹⁰¹ , R″ ¹⁰² and R″ ¹⁰³ is preferably a group exemplified as the cyclic aliphatic hydrocarbon group for R ¹⁰¹ above. Examples of the substituent include the same substituents that may substitute the cyclic aliphatic hydrocarbon group for R ¹⁰¹ .

The optionally substituted aromatic cyclic group for R″ ¹⁰³ is preferably a group exemplified as the aromatic hydrocarbon group for the cyclic hydrocarbon group for R ^101. As the substituent, , the same substituents that may substitute the aromatic hydrocarbon group in R ¹⁰¹ .

The chain alkyl group optionally having a substituent in R″ ¹⁰¹ is preferably a group exemplified as the chain alkyl group in R ^101. Having a substituent in R″ ¹⁰³ The preferred chain alkenyl group is preferably a group exemplified as the chain alkenyl group for R ¹⁰¹ .

In the above formulas (an-1) to (an-3), 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. V″ ¹⁰¹ is , a single bond, an alkylene group having 1 carbon atom (methylene group), or a fluorinated alkylene group having 1 to 3 carbon atoms are preferred.

In formulas (an-1) to (an-3), R ¹⁰² is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. R ¹⁰² is preferably a C 1-5 perfluoroalkyl group, preferably a fluorine atom, more preferably a fluorine atom.

In the formulas (an-1) to (an-3), v″ is an integer of 0 to 3, preferably 0 or 1. q″ is an integer of 1 to 20, preferably 1 It is an integer of up to 10, more preferably an integer of 1 to 5, still more preferably 1, 2 or 3, particularly preferably 1 or 2. n″ is 0 or 1;

- An anion represented by general formula (b1-a2) In formula (b1-a2), R ¹⁰⁴ and R ¹⁰⁵ are each independently a cyclic group optionally having a substituent, a substituent or a chain alkenyl group which may have a substituent, and examples thereof are the same as those for R ¹⁰¹ in formula (b1-a1). However, R ¹⁰⁴ and R ¹⁰⁵ may combine with each other to form a ring.
R ¹⁰⁴ and R ¹⁰⁵ are preferably a chain alkyl group which may have a substituent, and are a linear or branched alkyl group, or a linear or branched fluorinated alkyl group. is more preferable.
The chain alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 7 carbon atoms, and still more preferably 1 to 3 carbon atoms. The chain alkyl groups of R ¹⁰⁴ and R ¹⁰⁵ preferably have a smaller number of carbon atoms within the range of the number of carbon atoms described above, for reasons such as good solubility in resist solvents. In addition, in the chain alkyl groups of R ¹⁰⁴ and R ¹⁰⁵ , the greater the number of hydrogen atoms substituted with fluorine atoms, the stronger the acid strength, which is preferable.
The proportion of fluorine atoms in the chain alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all hydrogen atoms are substituted with fluorine atoms. is a perfluoroalkyl group.
In formula (b1-a2), V ¹⁰² and V ¹⁰³ are each independently a single bond, an alkylene group or a fluorinated alkylene group, and are the same as V ¹⁰¹ in formula (b1-a1). be done.
In formula (b1-a2), L ¹⁰¹ and L ¹⁰² are each independently a single bond or an oxygen atom.

- an anion represented by general formula (b1-a3) In formula (b1-a3), R ¹⁰⁶ to R ¹⁰⁸ are each independently a cyclic group optionally having a substituent, a substituent a chain alkyl group which may be substituted, or a chain alkenyl group which may have a substituent, and examples thereof are the same as those for R ¹⁰¹ in formula (b1-a1).
In formula (b1-a3), L ¹⁰³ to L ¹⁰⁵ are each independently a single bond, —CO— or —SO ₂ —.

Among the above, the anion moiety of the component (B1) is preferably an anion represented by the general formula (b1-a1). When the component (B1) having this anion as the anion part is used, the dimensional uniformity within the surface of the support can be further improved in resist pattern formation. For example, when a space-and-line pattern is formed, the deviation of the space width dimension (CD) is small, and a pattern with a uniform width can be easily formed with high accuracy.
Among these anions, anions represented by any of the above general formulas (an-1) to (an-3) are more preferable, and represented by either general formula (an-1) or (an-2). is more preferred, and the anion represented by general formula (an-1) is particularly preferred.

Specific examples of preferred component (B1) are given below.

The component (B1) contained in the resist composition may be used alone or in combination of two or more.

The ratio of component (B1) in component (B) is preferably 50% by mass or more, more preferably 75% by mass or more, and may be 100% by mass, relative to the total mass of component (B). When the ratio of component (B1) is at least the lower limit of the preferred range, foaming during high-temperature baking is further suppressed. In addition, when forming a resist pattern, good sensitivity can be easily maintained, and lithography properties (dimensional uniformity, etc.) are improved.

In the resist composition of the present embodiment, the content of component (B1) is preferably 1 to 40 parts by mass and 1.5 to 35 parts by mass with respect to 100 parts by mass of component (A). is more preferable, and 2 to 30 parts by mass is even more preferable.
When the content of component (B1) is at least the lower limit of the preferred range, foaming during high-temperature baking is further suppressed. In addition, when forming a resist pattern, good sensitivity can be easily maintained, and lithography properties (dimensional uniformity, etc.) are improved. On the other hand, if it is equal to or less than the upper limit of the preferable range, when each component of the resist composition is dissolved in an organic solvent, a uniform solution can be easily obtained, and the storage stability of the resist composition is further enhanced.

Regarding the (B2) component The resist composition of the present embodiment may contain an acid generator component (hereinafter referred to as "(B2) component") other than the (B1) component to the extent that the effects of the present invention are not impaired. .
The component (B2) is not particularly limited, and those hitherto 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; Acid generators: nitrobenzylsulfonate-based acid generators, iminosulfonate-based acid generators, disulfone-based acid generators and the like.

As the onium salt acid generator, for example, a compound represented by the following general formula (b-1) (hereinafter also referred to as "component (b-1)"), represented by general formula (b-2) A compound (hereinafter also referred to as "(b-2) component") or a compound represented by general formula (b-3) (hereinafter also referred to as "(b-3) component") can be mentioned.

［式中、Ｒ^１０１、Ｒ^１０４～Ｒ^１０８はそれぞれ独立に置換基を有していてもよい環式基、置換基を有していてもよい鎖状のアルキル基、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。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 an optionally substituted cyclic group, an optionally substituted chain alkyl group, or a substituted is a chain alkenyl group that may be R ¹⁰⁴ and R ¹⁰⁵ may combine with 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 divalent linking group containing a single bond or 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 part}
The anion portion of component (b-1) is the same as the anion represented by the general formula (b1-a1) described above.
The anion portion of the component (b-2) is the same as the anion represented by the general formula (b1-a2) described above.
The anion portion of component (b-3) is the same as the anion represented by the general formula (b1-a3) described above.

{cation part}
In the above formulas (b-1), (b-2), and (b-3), M′ ^m+ represents an m-valent onium cation (provided that it corresponds to the cation moiety in the general formula (b1) cations). Among these, sulfonium cations and iodonium cations are preferred.
m is an integer of 1 or more.

Preferred cation moieties ((M′ ^m+ ) _1/m ) include organic cations represented by general formulas (ca-1) to (ca-4) below.

［式中、Ｒ^２０１～Ｒ^２０７、およびＲ^２１１～Ｒ^２１２は、それぞれ独立に置換基を有していてもよいアリール基、アルキル基またはアルケニル基を表す。Ｒ^２０１～Ｒ^２０３、Ｒ^２０６～Ｒ^２０７、Ｒ^２１１～Ｒ^２１２は、相互に結合して式中のイオウ原子と共に環を形成してもよい。Ｒ^２０８～Ｒ^２０９は、それぞれ独立に水素原子または炭素数１～５のアルキル基を表す。Ｒ^２１０は、置換基を有していてもよいアリール基、置換基を有していてもよいアルキル基、置換基を有していてもよいアルケニル基、又は置換基を有していてもよい－ＳＯ_２－含有環式基である。Ｌ^２０１は、－Ｃ（＝Ｏ）－または－Ｃ（＝Ｏ）－Ｏ－を表す。Ｙ^２０１は、それぞれ独立に、アリーレン基、アルキレン基またはアルケニレン基を表す。ｘは１または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 optionally substituted aryl group, alkyl group or alkenyl group. R ²⁰¹ to R ²⁰³ , R ²⁰⁶ to R ²⁰⁷ and R ²¹¹ to R ²¹² may combine with 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. R ²¹⁰ is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted —SO ₂ —containing cyclic group. L ²⁰¹ represents -C(=O)- or -C(=O)-O-. Each Y ²⁰¹ independently represents an arylene group, an alkylene group or an alkenylene group. x is 1 or 2; W ²⁰¹ represents a (x+1)-valent linking group. ]

In the above general formulas (ca-1) to (ca-4), the aryl group for R ²⁰¹ to R ²⁰⁷ and R ²¹¹ to R ²¹² includes an unsubstituted aryl group having 6 to 20 carbon atoms, A phenyl group and a naphthyl group are preferred.
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 substituents that R ²⁰¹ to R ²⁰⁷ and R ²¹⁰ to R ²¹² may have include alkyl groups, halogen atoms, halogenated alkyl groups, carbonyl groups, cyano groups, amino groups, aryl groups, the above and groups represented by general formulas (ca-r-1) to (ca-r-7).

In general formulas (ca-1) to (ca-4) above, R ²⁰¹ to R ²⁰³ , R ²⁰⁶ to R ²⁰⁷ , and R ²¹¹ to R ²¹² are mutually bonded to form a ring together with the sulfur atom in the formula. When doing so, a sulfur atom, an oxygen atom, a hetero atom such as a nitrogen atom, a carbonyl group, -SO-, -SO ₂ -, -SO ₃ -, -COO-, -CONH- or -N(R _N )-( The R 3 _N is an alkyl group having 1 to 5 carbon atoms.). As the ring to be formed, one ring containing a sulfur atom in the formula in its ring skeleton is preferably a 3- to 10-membered ring including a sulfur atom, particularly a 5- to 7-membered ring. preferable. 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 phenoxathiine ring, a tetrahydro A thiophenium ring, a tetrahydrothiopyranium ring, and the like are included.

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. A ring may be formed.

R ²¹⁰ is an optionally substituted aryl group, an optionally substituted alkyl group, an optionally substituted alkenyl group, or an optionally substituted —SO ₂ —containing cyclic group.
The aryl group for R ²¹⁰ includes an unsubstituted aryl group having 6 to 20 carbon atoms, 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 2 to 10 carbon atoms.
The —SO ₂ -containing cyclic group optionally having a substituent for R ²¹⁰ is preferably a “—SO ₂ -containing polycyclic group” represented by the above general formula (a5-r-1). is more preferred.

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 obtained by removing one hydrogen atom from the aryl group exemplified as the aromatic hydrocarbon group for R ¹⁰¹ in the above formula (b1-a1).
Examples of the alkylene group and alkenylene group for Y ²⁰¹ include groups exemplified as the chain alkyl group and chain alkenyl group for R ¹⁰¹ in the above formula (b1-a1) from which one hydrogen atom has been removed. .

In formula (ca-4), x is 1 or 2.
W ²⁰¹ is a (x+1)-valent, ie divalent or trivalent linking group.
The divalent linking group for W ²⁰¹ is preferably a divalent hydrocarbon group which may have a substituent, and has a substituent similar to Ya ²¹ in the above general formula (a2-1). An optional divalent hydrocarbon group can be exemplified. The divalent linking group in W ²⁰¹ may be linear, branched or cyclic, preferably cyclic. Among them, a group in which two carbonyl groups are combined at both ends of an arylene group is preferable. The arylene group includes a phenylene group, a naphthylene group and the like, and a phenylene group is particularly preferred.
The trivalent linking group for W ²⁰¹ includes a group obtained by removing one hydrogen atom from the divalent linking group for W ²⁰¹ , a group obtained by further bonding the divalent linking group to the divalent linking group, and the like. mentioned. The trivalent linking group for W ²⁰¹ is preferably a group in which two carbonyl groups are bonded to an arylene group.

Specific examples of suitable cations represented by the formula (ca-1) include cations represented by the following chemical formulas (ca-1-56) to (ca-1-71).

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

[In the formula, R″ ²⁰¹ is a hydrogen atom or a substituent, and the substituent is the same as those exemplified as the substituents that R ²⁰¹ to R ²⁰⁷ and R ²¹⁰ to R ²¹² may have. is.]

Specific examples of suitable cations represented by the formula (ca-2) include diphenyliodonium cations and bis(4-tert-butylphenyl)iodonium cations.

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

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

Among the above, the cation moiety ((M' ^m+ ) _1/m ) is preferably a cation represented by general formula (ca-1).

In the resist composition of this embodiment, the component (B2) may be used singly or in combination of two or more.
When the resist composition contains the component (B2), the content of the component (B2) in the resist composition is preferably less than 50 parts by mass, preferably 1 to 20 parts by mass, per 100 parts by mass of the component (A). is more preferred, and 1 to 10 parts by mass is even more preferred.
By setting the content of the component (B2) within the above preferable range, the pattern formation is sufficiently performed. Moreover, when each component of the resist composition is dissolved in an organic solvent, a uniform solution can be easily obtained, and the storage stability of the resist composition is improved, which is preferable.

<(S) Component>
In the resist composition of the present embodiment, the organic solvent component (S) (component (S)) may be any component as long as it can dissolve each component to be blended to form a uniform solution. Any solvent can be appropriately selected and used from known solvents for mold resist compositions.
Examples of 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; ethylene glycol, diethylene glycol, propylene glycol. , polyhydric alcohols such as dipropylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate or dipropylene glycol monoacetate; said polyhydric alcohols or compounds having an ester bond Derivatives of polyhydric alcohols such as compounds having an ether bond such as monoalkyl ethers such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, monophenyl ether [among these, propylene glycol monomethyl ether acetate ( PGMEA), propylene glycol monomethyl ether (PGME) is preferred]; cyclic ethers such as dioxane; methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methoxy Esters such as methyl propionate and ethyl ethoxypropionate; anisole, ethylbenzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, aromatic organic solvents such as cymene and mesitylene; dimethylsulfoxide (DMSO);

In the resist composition of the present embodiment, the (S) component may be used singly or as a mixed solvent of two or more.
Among the above, PGMEA, PGME, γ-butyrolactone, EL, and cyclohexanone are preferable as the (S) component.

A mixed solvent obtained by mixing PGMEA and a polar solvent is also preferable. The blending ratio (mass ratio) thereof may be appropriately determined in consideration of compatibility between PGMEA and the polar solvent, etc., preferably 1:9 to 9:1, more preferably 2:8 to 8:2. It is preferable to be within the range.
More specifically, when EL or cyclohexanone is blended as a 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 a polar solvent, the mass ratio of PGMEA:PGME is preferably 1:9-9:1, more preferably 2:8-8:2. Further, a mixed solvent of PGMEA, PGME and cyclohexanone is also preferred.
Further, as the component (S), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, as a mixing ratio, the mass ratio of the former to the latter is preferably 70:30 to 95:5.

In the resist composition of this embodiment, the (S) component is used so that the solid content concentration in the resist composition is 30% by mass or more. That is, the solid content concentration in the resist composition is 30% by mass or more, preferably 30 to 50% by mass, more preferably 30 to 40% by mass.
When the solid content concentration is at least the lower limit of the above range, it becomes easy to uniformly form a thick resist film on the support. On the other hand, when the content is equal to or less than the upper limit of the preferable range, the viscosity of the resist composition can be reduced, and the coatability to the support, etc. can be enhanced.

Further, the concentration of the polymer compound (A1) in the total solid content in the resist composition of the present embodiment is preferably 90% by mass or more, more preferably 90 to 99% by mass, and 95% by mass. More preferably, it is up to 99% by mass.
If the concentration of component (A1) in the total solid content is at least the lower limit of the preferred range, a thick resist film can be easily formed on the support.

<Optional component>
The resist composition of the present embodiment may further contain components (optional components) other than the components (A), (B) and (S) described above.
Examples of such optional components include components (D), (E), and (F) shown below.

<<(D) Component: Acid diffusion controller component>>
Component (D) acts as a quencher (acid diffusion control agent) that traps acid generated by exposure in the resist composition.
Component (D) includes, for example, a photodegradable base (D1) that decomposes upon exposure to lose acid diffusion controllability (hereinafter referred to as "(D1) component"), and a nitrogen-containing organic base that does not fall under component (D1). Compound (D2) (hereinafter referred to as "component (D2)") and the like.

About the (D1) component By using a resist composition containing the (D1) component, the contrast between the exposed and unexposed portions of the resist film can be further improved when forming a resist pattern.
The component (D1) is not particularly limited as long as it is decomposed by exposure to light and loses the acid diffusion controllability. ), a compound represented by the following general formula (d1-2) (hereinafter referred to as “(d1-2) component”) and a compound represented by the following general formula (d1-3) (hereinafter referred to as “(d1- 3) One or more compounds selected from the group consisting of "components" are preferred.
Components (d1-1) to (d1-3) do not act as quenchers because they decompose in the exposed area of the resist film and lose the acid diffusion controllability (basicity), and in the unexposed area of the resist film Acts as a quencher.

［式中、Ｒｄ^１～Ｒｄ^４は置換基を有していてもよい環式基、置換基を有していてもよい鎖状のアルキル基、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。但し、式（ｄ１－２）中のＲｄ^２における、Ｓ原子に隣接する炭素原子にはフッ素原子は結合していないものとする。Ｙｄ^１は単結合又は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価の有機カチオンである。］

[In the formula, Rd ¹ to Rd ⁴ are optionally substituted cyclic groups, optionally substituted chain alkyl groups, or optionally substituted chain is an alkenyl group of However, it is assumed that no fluorine atom is bonded to the carbon atom adjacent to the S atom in Rd ² in formula (d1-2). Yd ¹ is a single bond or a divalent linking group. m is an integer of 1 or more, and each M ^m+ is independently an m-valent organic cation. ]

{(d1-1) component}
..anion portion In formula (d1-1), Rd ¹ is an optionally substituted cyclic group, an optionally substituted chain alkyl group, or a substituted may be a chain alkenyl group, and examples thereof are the same as those for R ¹⁰¹ in the above formula (b1-a1).
Among these, Rd ¹ is an optionally substituted aromatic hydrocarbon group, an optionally substituted aliphatic cyclic group, or an optionally substituted A chain alkyl group is preferred. Examples of substituents that these groups may have include a hydroxyl group, an oxo group, an alkyl group, an aryl group, a fluorine atom, a fluorinated alkyl group, and general formulas (a2-r-1) to (a2-r- 7), lactone-containing cyclic groups, ether bonds, ester bonds, or combinations thereof. When it contains an ether bond or an ester bond as a substituent, it may be via an alkylene group, and the substituents in this case are represented by the above formulas (y-al-1) to (y-al-5), respectively. is preferred.
A phenyl group or a naphthyl group is more preferable as the aromatic hydrocarbon group.
More preferably, the aliphatic cyclic group is a group obtained by removing one or more hydrogen atoms from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
The chain alkyl group preferably has 1 to 10 carbon atoms, and specific examples thereof include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, Linear alkyl groups such as nonyl group and decyl group; 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl 2-ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and other branched alkyl groups.

When the chain alkyl group is a fluorinated alkyl group having a fluorine atom or a fluorinated alkyl group as a substituent, the fluorinated alkyl group preferably has 1 to 11 carbon atoms, more preferably 1 to 8 carbon atoms. , more preferably 1 to 4 carbon atoms. The fluorinated alkyl group may contain atoms other than fluorine atoms. Atoms other than a fluorine atom include, for example, an oxygen atom, a sulfur atom, a nitrogen atom, and the like.
Rd ¹ is preferably a fluorinated alkyl group in which some or all of the hydrogen atoms constituting the linear alkyl group are substituted with fluorine atoms, and the number of hydrogen atoms constituting the linear alkyl group is preferably A fluorinated alkyl group (straight-chain perfluoroalkyl group) in which all are substituted with fluorine atoms is particularly preferred.

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

Cation Moiety In formula (d1-1), M ^m+ is an m-valent organic cation.
Examples of the organic cation of M ^m+ include preferably the same cations as those represented by the general formulas (ca-1) to (ca-4), and the organic cation represented by the general formula (ca-1). A cation is more preferred, and a cation represented by each of the above formulas (ca-1-1) to (ca-1-71) is even more preferred.
Component (d1-1) may be used alone or in combination of two or more.

{(d1-2) component}
..anion portion In formula (d1-2), Rd ² is an optionally substituted cyclic group, an optionally substituted chain alkyl group, or a substituted is a chain alkenyl group which may be substituted, and includes the same groups as those for R ¹⁰¹ in the formula (b1-a1).
However, the carbon atom adjacent to the S atom in Rd ² is not bonded to a fluorine atom (not fluorine-substituted). As a result, the anion of component (d1-2) becomes a moderately weak acid anion, and the quenching ability of component (D) is improved.
Rd ² 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, more preferably 3 to 10 carbon atoms. Aliphatic cyclic groups include groups obtained by removing one or more hydrogen atoms from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, etc. (which may have substituents); It is more preferable to be a group from which the above hydrogen atoms are removed.
^The hydrocarbon group of Rd ² may have a substituent, and examples of the substituent include the hydrocarbon group (aromatic hydrocarbon group, aliphatic cyclic group, (chain alkyl group) may have the same substituents as those described above.

Preferred specific examples of the anion portion of component (d1-2) are shown below.

Cation Moiety In formula (d1-2), M ^m+ is an m-valent organic cation and is the same as M ^m+ in formula (d1-1).
Component (d1-2) may be used alone or in combination of two or more.

{(d1-3) component}
..anion portion In formula (d1-3), Rd ³ is an optionally substituted cyclic group, an optionally substituted chain alkyl group, or a substituted may be a chain alkenyl group, and examples are the same as those for R ¹⁰¹ in the formula (b1-a1), a cyclic group containing a fluorine atom, a chain alkyl group, or a chain alkenyl group is preferably Among them, a fluorinated alkyl group is preferred, and the same fluorinated alkyl group as Rd ¹ is more preferred.

In formula (d1-3), Rd ⁴ is an optionally substituted cyclic group, an optionally substituted chain alkyl group, or an optionally substituted It is a chain alkenyl group and includes the same groups as those described for R ¹⁰¹ in the formula (b1-a1).
Among them, an optionally substituted alkyl group, alkoxy group, alkenyl group, and cyclic group are preferable.
The alkyl group for Rd ⁴ is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, specifically a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group and an isobutyl group. , tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like. A portion of the hydrogen atoms of the alkyl group of ^Rd4 may be substituted with a hydroxyl group, a cyano group, or the like.
The alkoxy group for Rd ⁴ is preferably an alkoxy group having 1 to 5 carbon atoms, and specific examples of the alkoxy group having 1 to 5 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n- butoxy group and tert-butoxy group. Among them, a methoxy group and an ethoxy group are preferable.

Examples of the alkenyl group for Rd ⁴ include those similar to those for R ¹⁰¹ in the above formula (b1-a1), preferably a vinyl group, a propenyl group (allyl group), a 1-methylpropenyl group and 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 for Rd ⁴ include those similar to R ¹⁰¹ in the above formula (b1-a1), and cycloalkanes such as cyclopentane, cyclohexane, adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. An alicyclic group in which one or more hydrogen atoms are removed, or an aromatic group such as a phenyl group or a naphthyl group is preferred. When Rd ⁴ is an alicyclic group, the resist composition dissolves well in organic solvents, resulting in good lithography properties. Further, when Rd ⁴ is an aromatic group, the resist composition has excellent light absorption efficiency and good sensitivity and lithography properties.

In formula (d1-3), Yd ¹ is a single bond or a divalent linking group.
The divalent linking group in Yd ¹ is not particularly limited, but may be a divalent hydrocarbon group (aliphatic hydrocarbon group, aromatic hydrocarbon group) optionally having a substituent, 2 containing a hetero atom, valent linking groups and the like. These are respectively the divalent hydrocarbon group optionally having a substituent and the heteroatom mentioned in the description of the divalent linking group for Ya ^x1 in the general formula (a10-1) The same as the divalent linking group containing
Yd ¹ is preferably a carbonyl group, an ester bond, an amide bond, an alkylene group, or a combination thereof. The alkylene group is more preferably a linear or branched alkylene group, more preferably a methylene group or an ethylene group.

Preferred specific examples of the anion portion of component (d1-3) are shown below.

Cation Moiety In formula (d1-3), M ^m+ is an m-valent organic cation and is the same as M ^m+ in formula (d1-1).
Component (d1-3) may be used alone or in combination of two or more.

As the component (D1), any one of the above components (d1-1) to (d1-3) may be used alone, or two or more of them may be used in combination.
When the resist composition contains the component (D1), the content of the component (D1) in the resist composition is preferably 0.5 to 10 parts by mass per 100 parts by mass of the component (A). 5 to 8 parts by mass is more preferable, and 1 to 8 parts by mass is even more preferable.
When the content of the component (D1) is at least the lower limit of the above preferred range, it is easy to obtain particularly good lithography properties and resist pattern shape. On the other hand, when it is equal to or less than the upper limit of the preferred range, the sensitivity can be maintained well, and the throughput is also excellent.

- Component (D2) The acid diffusion control agent component may contain a nitrogen-containing organic compound component (hereinafter referred to as "component (D2)") that does not correspond to component (D1) above.
Component (D2) is not particularly limited as long as it acts as an acid diffusion control agent and does not correspond to component (D1), and any known component may be used. Among them, aliphatic amines are preferable, and among these, secondary aliphatic amines and tertiary aliphatic amines are more preferable.
Aliphatic amines are amines having one or more aliphatic groups, which preferably have 1 to 12 carbon atoms.
Aliphatic amines include amines (alkylamines or alkylalcohol 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, or cyclic amines.
Specific examples of alkylamines and alkylalcoholamines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine and n-decylamine; diethylamine, di-n-propylamine, Dialkylamines such as di-n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine (triamylamine), Trialkylamines such as tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, tri-n-dodecylamine; diethanolamine, triethanolamine , diisopropanolamine, triisopropanolamine, di-n-octanolamine and tri-n-octanolamine. Among these, trialkylamines having 5 to 10 carbon atoms are more preferable, and tri-n-pentylamine or tri-n-octylamine is particularly preferable.

Cyclic amines include, for example, heterocyclic compounds containing a nitrogen atom as a heteroatom. The heterocyclic compound may be monocyclic (aliphatic monocyclic amine) or polycyclic (aliphatic polycyclic amine).
Specific examples of aliphatic monocyclic amines include piperidine and piperazine.
As the aliphatic polycyclic amine, those having 6 to 10 carbon atoms are preferable, and specifically, 1,5-diazabicyclo[4.3.0]-5-nonene, 1,8-diazabicyclo[5. 4.0]-7-undecene, hexamethylenetetramine, 1,4-diazabicyclo[2.2.2]octane and the like.

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

Moreover, you may use an aromatic amine as a (D2) component.
Aromatic amines include 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxycarbonylpyrrolidine and the like.

(D2) component may be used individually by 1 type, and may be used in combination of 2 or more type.
When the resist composition contains component (D2), the content of component (D2) in the resist composition is preferably 0.01 to 5 parts by mass per 100 parts by mass of component (A). . By setting the content of the component (D2) within the above preferred range, the resist pattern shape, storage stability over time, etc. are improved.

<<Component (E): At least one compound selected from the group consisting of organic carboxylic acids, phosphorus oxoacids, and derivatives thereof>>
The resist composition of the present embodiment contains an organic carboxylic acid and a phosphorus oxoacid and its derivatives as optional components for the purpose of preventing sensitivity deterioration and improving the resist pattern shape, storage stability over time, and the like. At least one compound (E) selected from the group (hereinafter referred to as "(E) component") can be contained.
Suitable examples of organic carboxylic acids include acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, and salicylic acid.
Phosphorus oxoacids include phosphoric acid, phosphonic acid, phosphinic acid, etc. Among these, phosphonic acid is particularly preferred.
Examples of the oxoacid derivative of phosphorus include esters obtained by substituting a hydrogen atom of the above oxoacid with a hydrocarbon group. Examples of the hydrocarbon group include alkyl groups having 1 to 5 carbon atoms, 15 aryl groups and the like.
Derivatives of phosphoric acid include phosphoric acid esters such as di-n-butyl phosphate and diphenyl phosphate.
Phosphonic acid derivatives include phosphonic acid esters such as dimethyl phosphonic acid, di-n-butyl phosphonic acid, phenylphosphonic acid, diphenyl phosphonic acid and dibenzyl phosphonic acid.
Phosphinic acid derivatives include phosphinic acid esters and phenylphosphinic acid.
In the resist composition of this embodiment, the component (E) may be used alone or in combination of two or more.
When the resist composition contains component (E), the content of component (E) is preferably in the range of 0.01 to 5 parts by mass per 100 parts by mass of component (A).

<<(F) component: Fluorine additive component>>
The resist composition of the present embodiment may contain a fluorine additive component (hereinafter referred to as "component (F)") in order to impart water repellency to the resist film or improve lithography properties.
As the component (F), for example, JP-A-2010-002870, JP-A-2010-032994, JP-A-2010-277043, JP-A-2011-13569, JP-A-2011-128226. can be used.
More specific examples of component (F) include polymers having a structural unit (f1) represented by the following formula (f1-1). Examples of the polymer include a polymer (homopolymer) consisting only of a structural unit (f1) represented by the following formula (f1-1); a copolymer of the structural unit (f1) and the structural unit (a1). is preferably a copolymer of the structural unit (f1), a structural unit derived from acrylic acid or methacrylic acid, and the structural unit (a1). Here, as the structural unit (a1) to be copolymerized with the structural unit (f1), a structural unit derived from 1-ethyl-1-cyclooctyl (meth)acrylate, 1-methyl-1-adamantyl ( Structural units derived from meth)acrylates are preferred.

［式中、Ｒは前記と同様であり、Ｒｆ^１０２及び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及び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 defined 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, 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 α-position carbon atom is the same as described above. R is preferably a hydrogen atom or a methyl group.
In formula (f1-1), the halogen atoms of Rf ¹⁰² and Rf ¹⁰³ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, with a fluorine atom being particularly preferred. Examples of the alkyl group having 1 to 5 carbon atoms for Rf ¹⁰² and Rf ¹⁰³ include the same alkyl groups having 1 to 5 carbon atoms as the above R, and a methyl group or an ethyl group is preferable. Specific examples of the halogenated alkyl group having 1 to 5 carbon atoms of Rf ¹⁰² and Rf ¹⁰³ include groups in which some or all of the hydrogen atoms in the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. be done. The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is particularly preferred. Among them, Rf ¹⁰² and Rf ¹⁰³ are preferably a hydrogen atom, a fluorine atom, or an alkyl group having 1 to 5 carbon atoms, and more preferably a hydrogen atom, a fluorine atom, a methyl group, or an ethyl group.
In formula (f1-1), nf ¹ is an integer of 1 to 5, preferably an integer of 1 to 3, more preferably 1 or 2.

In formula (f1-1), Rf ¹⁰¹ is an organic group containing a fluorine atom, preferably a hydrocarbon group containing a fluorine atom.
The hydrocarbon group containing a fluorine atom may be linear, branched or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms. , and 1 to 10 carbon atoms are particularly preferred.
In the hydrocarbon group containing a fluorine atom, 25% or more of the hydrogen atoms in the hydrocarbon group are preferably fluorinated, more preferably 50% or more are fluorinated, and 60% or more are Fluorination is particularly preferable because the hydrophobicity of the resist film is increased.
Among them, Rf ¹⁰¹ is more preferably a fluorinated hydrocarbon group having 1 to 6 carbon atoms, such as a trifluoromethyl group, —CH ₂ —CF ₃ , —CH ₂ —CF ₂ —CF ₃ , —CH(CF ₃ ) ₂ , -CH ₂ -CH ₂ -CF ₃ , -CH ₂ -CH ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₃ are particularly preferred.

The weight-average molecular weight (Mw) of component (F) (polystyrene equivalent by gel permeation chromatography) is preferably 1,000 to 50,000, more preferably 5,000 to 40,000, and particularly preferably 10,000 to 30,000. When the Mw of the component (F) is at most the upper limit of the preferred range, it has sufficient solubility in a resist solvent for use as a resist, and when it is at least the lower limit of the preferred range, it is resistant. The dry etching property and the cross-sectional shape of the resist pattern are improved, and the water repellency of the resist film surface is favorably expressed.
The dispersity (Mw/Mn) of component (F) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and particularly preferably 1.2 to 2.5.

In the resist composition of this embodiment, the component (F) may be used alone or in combination of two or more.
When the resist composition contains component (F), the content of component (F) is preferably 0.5 to 10 parts by mass per 100 parts by mass of component (A).

The resist composition of the present invention further optionally contains miscible additives such as additional resins, surfactants, dissolution inhibitors, plasticizers, stabilizers, colorants to improve the performance of the resist film. , an antihalation agent, a dye, and the like can be added as appropriate.

(Resist pattern forming method)
A second aspect of the present invention comprises a step (i) of forming a resist film on a support using the resist composition according to the first aspect described above, a step (ii) of exposing the resist film, and The resist pattern forming method has a step (iii) of developing the resist film after the exposure to form a resist pattern.
One embodiment of such a resist pattern forming method includes, for example, a resist pattern forming method performed as follows.

Step (i):
First, on a support, the resist composition of the above-described embodiment is applied with a spinner or the like, and baked (post-apply bake (PAB)) treatment is performed, for example, at a temperature of 80 to 150 ° C. for 40 to 120 seconds. It is preferably applied for 60 to 90 seconds to form a resist film.

Step (ii):
Next, the resist film is subjected to selective exposure such as exposure through a mask having a predetermined pattern (mask pattern) using an exposure apparatus such as a KrF exposure apparatus, and then baked (post An exposure bake (PEB) treatment is performed, for example, at a temperature of 80 to 150° C. for 40 to 120 seconds, preferably 60 to 90 seconds.

Step (iii):
Next, the resist film is developed. The developing process is carried out using an alkaline developer in the case of the alkali development process, and using a developer containing an organic solvent (organic developer) in the case of the solvent development process.
Rinsing treatment is preferably performed after the development treatment. As for the rinsing treatment, water rinsing using pure water is preferable in the case of the alkali developing process, and a rinsing solution containing an organic solvent is preferably used in the case of the solvent developing process.
In the case of the solvent development process, after the development processing or the rinsing processing, a processing for removing the developer or the rinsing liquid adhering to the pattern with a supercritical fluid may be performed.

After development processing or rinsing processing, drying is performed. In some cases, baking treatment (post-baking) may be performed after the development treatment. The baking treatment (post-baking) here is performed, for example, at a temperature of 180° C. or higher, preferably 180 to 200° C. for 40 to 120 seconds, preferably 60 to 90 seconds.
Thus, a resist pattern can be formed.

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

The method of forming a resist pattern according to the embodiment is a method useful for forming a thick resist film. Even if the thickness of the resist film formed in the step (i) is, for example, 1 to 10 μm, preferably 6 μm or more, further 7 μm or more, and particularly 8 μm or more, the resist pattern can be formed satisfactorily. It can be formed stably in shape.

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

The exposure method of the resist film may be normal exposure (dry exposure) performed in air or an inert gas such as nitrogen, or may be liquid immersion lithography.
In immersion exposure, the space between the resist film and the lowest lens of the exposure device is filled in advance with a solvent (immersion medium) having a refractive index greater than that of air, and exposure (immersion exposure) is performed in this state. exposure method.
As the liquid immersion medium, a solvent having a refractive index higher than that of air and lower than that of the resist film to be exposed is preferable. The refractive index of such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index higher than that of air and lower than that of the resist film include water, fluorine-based inert liquids, silicon-based solvents, and hydrocarbon-based solvents.
Specific examples _of fluorine-based inert liquids include fluorine _- based compounds such _{as C3HCl2F5} , _{C4F9OCH3 , C4F9OC2H5 , and C5H3F7} as _{main components .} Examples include liquids, and those having a boiling point of 70 to 180°C are preferable, and those of 80 to 160°C are more preferable. It is preferable that the fluorine-based inert liquid has a boiling point within the above range because the medium used for liquid immersion can be removed by a simple method after the exposure is completed.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of an alkyl group are substituted with fluorine atoms is particularly preferable. Specific examples of perfluoroalkyl compounds include perfluoroalkyl ether compounds and perfluoroalkylamine compounds.
Further, specifically, the perfluoroalkyl ether compound includes perfluoro(2-butyl-tetrahydrofuran) (boiling point 102° C.), and the perfluoroalkylamine compound includes perfluorotributylamine ( boiling point 174°C).
Water is preferably used as the immersion medium from the viewpoints of cost, safety, environmental concerns, versatility, and the like.

Examples of the alkaline developer used for development processing in the alkaline development process include a 0.1 to 10% by mass tetramethylammonium hydroxide (TMAH) aqueous solution.
The organic solvent contained in the organic developer used for development in the solvent development process may be any one capable of dissolving the component (A) (component (A) before exposure), and may be selected from known organic solvents. It can be selected as appropriate. Specific examples include polar solvents such as ketone-based solvents, ester-based solvents, alcohol-based solvents, nitrile-based solvents, amide-based solvents, ether-based solvents, and hydrocarbon-based solvents.
A ketone solvent is an organic solvent containing C--C(=O)--C in its structure. An ester solvent is an organic solvent containing C—C(=O)—O—C in its structure. An alcoholic solvent is an organic solvent containing an alcoholic hydroxyl group in its structure. "Alcoholic hydroxyl group" means a hydroxyl group attached to a carbon atom of an aliphatic hydrocarbon group. A nitrile-based solvent is an organic solvent containing a nitrile group in its structure. An amide-based solvent is an organic solvent containing an amide group in its structure. Ether-based solvents are organic solvents containing C—O—C in their structure.
Among organic solvents, there are also organic solvents that contain multiple types of functional groups that characterize the above solvents in their structures. shall be For example, diethylene glycol monomethyl ether corresponds to both alcohol-based solvents and ether-based solvents in the above classification.
The hydrocarbon-based solvent is a hydrocarbon solvent that is composed of an optionally halogenated hydrocarbon and has no substituents other than halogen atoms. A halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is preferable.
As the organic solvent contained in the organic developer, among the above, polar solvents are preferable, and ketone-based solvents, ester-based solvents, nitrile-based solvents, and the like are preferable.

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, and methyl ethyl ketone. , methyl isobutyl ketone, acetylacetone, acetonyl acetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methylnaphthyl ketone, isophorone, propylene carbonate, γ-butyrolactone, methyl amyl ketone (2-heptanone) and the like. Among these, methyl amyl ketone (2-heptanone) is preferable as the ketone solvent.

Examples of ester solvents include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono Propyl 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 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, formic acid Propyl, ethyl lactate, butyl lactate, propyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, propionic acid Ethyl, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate , propyl-3-methoxypropionate, and the like. Among these, butyl acetate is preferable as the ester solvent.

Nitrile solvents include, for example, acetonitrile, propionitrile, valeronitrile, butyronitrile and the like.

Known additives can be added to the organic developer as needed. Examples of such additives include surfactants. Although the surfactant is not particularly limited, for example, ionic or nonionic fluorine-based and/or silicon-based surfactants can be used. As the surfactant, a nonionic surfactant is preferable, and a nonionic fluorine-based surfactant or a nonionic silicon-based surfactant is more preferable.
When a surfactant is blended, its blending amount is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and 0.01 to 0.5% by mass, relative to the total amount of the organic developer. 5% by mass is more preferred.

The development treatment can be carried out by a known development method, for example, a method of immersing the support in a developer for a certain period of time (dip method), or a method in which the developer is piled up on the surface of the support by surface tension and remains stationary for a certain period of time. method (paddle method), method of spraying the developer onto the surface of the support (spray method), and application of the developer while scanning the developer dispensing nozzle at a constant speed onto the support rotating at a constant speed. A continuous method (dynamic dispensing method) and the like can be mentioned.

As the organic solvent contained in the rinsing solution used for the rinsing treatment after the development treatment in the solvent development process, for example, among the organic solvents exemplified as the organic solvents used for the organic developer, those that hardly dissolve the resist pattern are appropriately selected. can be used as Usually, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents and ether solvents is used. Among these, at least one selected from hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, alcohol-based solvents and amide-based solvents is preferable, and at least one selected from alcohol-based solvents and ester-based solvents is more preferable. Alcoholic solvents are preferred, and alcoholic solvents are 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 linear, branched or 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. be done. Among these, 1-hexanol, 2-heptanol and 2-hexanol are preferred, and 1-hexanol and 2-hexanol are more preferred.
Any one of these organic solvents may be used alone, or two or more thereof may be used in combination. Moreover, you may mix with organic solvents and water other than the above, and you may use it. However, considering 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 even more preferably 3% by mass, relative to the total amount of the rinse solution. The following are particularly preferred.
Known additives can be added to the rinse solution as needed. Examples of such additives include surfactants. Examples of surfactants include those mentioned above, preferably nonionic surfactants, more preferably nonionic fluorine-based surfactants or nonionic silicon-based surfactants.
When a surfactant is blended, its blending amount is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and 0.01 to 0.5% by mass, relative to the total amount of the rinse liquid. % is more preferred.

Rinsing treatment (cleaning treatment) using a rinse liquid can be performed by a known rinsing method. The rinsing method includes, for example, a method of continuously applying the rinse solution onto the support rotating at a constant speed (rotation coating method), a method of immersing the support in the rinse solution for a given period of time (dip method), A method of spraying a rinsing liquid onto the support surface (spray method) and the like can be mentioned.

The resist composition of the present embodiment described above contains a polymer compound (A1) having a structural unit (a10) and a structural unit (a1), and an acid generator (B1) having a cation moiety with a specific structure. and the solid content concentration in the resist composition is 30% by mass or more.
In the formation of a resist pattern using a resist composition containing both the component (A1) and the component (B1) and having a solid content concentration of 30% by mass or more, particularly a thick resist film is formed. Even when it is carried out, for example, it is possible to improve the uniformity of the pattern dimension, etc., and the lithography characteristics are excellent. In addition, the coating property on the support is also good, and a resist film having a uniform thickness can be easily formed. Furthermore, foaming from the resist pattern during high-temperature baking, which has conventionally been a problem, is suppressed. As described above, according to the resist composition of the present embodiment, a thick resist pattern can be stably formed in a favorable shape.

Such a resist composition and resist pattern forming method are useful, for example, in applications where a thick resist film is required. In addition, such a resist composition and a resist pattern forming method are useful for processing a multi-step structure, and by applying the present invention, memory film lamination (three-dimensionalization, manufacturing of large-capacity memory) ) can be realized with high accuracy.

EXAMPLES 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>
(Example 1, Comparative Examples 1 to 4)
Each component shown in Table 1 was mixed and dissolved in a mixed solvent (propylene glycol monomethyl ether/propylene glycol monomethyl ether acetate=8/2 (mass ratio)) to prepare a resist composition of each example. Table 1 shows the solid content concentration in the resist composition of each example.

In Table 1, each abbreviation has the following meaning. The numbers in [ ] are the compounding amounts (parts by mass).
(A)-1: A polymer compound represented by the following chemical formula (A1-1). The weight average molecular weight (Mw) in terms of standard polystyrene obtained by GPC measurement was 10000, and the molecular weight dispersity (Mw/Mn) was 1.8. The copolymer compositional ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by ¹³ C-NMR was 1/m/n=60/20/20.
(A)-2: A polymer compound represented by the following chemical formula (A1-2). The weight average molecular weight (Mw) in terms of standard polystyrene obtained by GPC measurement was 20000, and the molecular weight dispersity (Mw/Mn) was 1.8. The copolymer compositional ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by ¹³ C-NMR was 1/m/n=60/20/20.

(B1)-1: A compound represented by the following chemical formula (B1-1).
(B2)-1: A compound represented by the following chemical formula (B2-1).
(B2)-2: N-(trifluoromethanesulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide.

(D)-1: Triamylamine.
(E)-1: Phenylphosphonic acid.

<Formation of resist pattern>
Step (i):
An organic antireflection film composition "DUV-42P" (trade name, manufactured by Brewer Science) was applied onto an 8-inch silicon wafer using a spinner, and baked on a hot plate at 180°C for 60 seconds. By drying, an organic antireflection film having a thickness of 65 nm was formed.
On the organic antireflection film, the resist composition of each example is applied using a spinner, and dried by pre-baking (PAB) treatment on a hot plate at 140 ° C. for 90 seconds to obtain a film thickness. A resist film of 8 μm was formed.
When the resist composition of Comparative Example 4 was used, a resist film having a film thickness of 8 μm could not be formed, so the subsequent operations were not performed.

Step (ii):
Next, KrF excimer laser light (248 nm) is applied to the resist film by a KrF exposure apparatus NSR-S205C (manufactured by Nikon; NA (numerical aperture) = 0.68, σ = 0.60) as a mask pattern (6 % halftone) at the optimum exposure dose (Eop) for each resist composition.
After that, a post-exposure bake (PEB) treatment was performed at 115° C. for 90 seconds.

Step (iii):
Next, using a 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution "NMD-3" (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) as a developer, alkali development was performed at 23° C. for 60 seconds. rice field.
Thereafter, using pure water, water rinsing was performed for 30 seconds, followed by drying by shaking off.

As a result of <Formation of resist pattern> described above, in any of the examples (Example 1 and Comparative Examples 1 to 3), a space-and-line pattern with a space width of 3.75 μm and a pitch width of 7.5 μm was formed on the resist film. (hereinafter referred to as "SL pattern") was formed.

[Evaluation of dimensional uniformity (CDU) within the support surface (Shot)]
For each SL pattern obtained, the SL pattern is observed from the sky by a critical dimension SEM (scanning electron microscope, acceleration voltage 300 V, product name: S-9380, manufactured by Hitachi High-Technologies Corporation). The space width (nm) of was measured. The triple value (3σ) of the standard deviation (σ) calculated from the measurement results was obtained, and the dimensional uniformity (CDU) within the support surface (Shot) was evaluated according to the following evaluation criteria. This evaluation result is shown in Table 2 as "CDU".
Evaluation Criteria A: 3σ is 15 nm or less.
○: 3σ is more than 15 nm and 20 nm or less.
x: 3σ exceeds 20 nm.
The smaller the value of 3σ obtained in this manner, the higher the dimensional (CD) uniformity of the space width formed in the resist film.

[Evaluation of film thickness uniformity within support surface (Shot)]
In the above [evaluation of dimensional uniformity (CDU) within the support surface (shot)], the resist compositions of Example 1, Comparative Example 1 and Comparative Example 3, which had good results, were subjected to the above <resist pattern The film thickness uniformity of the resist film having a film thickness of 8 μm after the pre-baking (PAB) treatment in the step (i) of <Formation> was evaluated as follows.
The film thickness (Å) of the resist film at 10 locations (equal intervals) between both ends of the diameter of the silicon wafer was measured using Nanospec 7001-0066XPW (product name, manufactured by Nanometrics Japan), and evaluated as follows. The film thickness uniformity within the support surface (shot) was evaluated according to the standard. This evaluation result is shown in Table 2 as "film thickness uniformity".
Evaluation Criteria ◯: Film thickness uniformity is high (when the difference in film thickness within a shot is ±25 nm or less).
x: Poor film thickness uniformity (when the difference in film thickness within a shot exceeds ±25 nm).

[Evaluation of presence or absence of foaming]
In the above [Evaluation of film thickness uniformity], for each resist composition of Example 1 and Comparative Example 1, the results were good, and the steps (i), (ii) and After (iii), that is, after drying by shaking off, heating (post-baking) was performed at 180° C. for 60 seconds, and the presence or absence of foaming from the resist pattern at that time was visually evaluated. The results are shown in Table 2 as "presence or absence of foaming".

From the results shown in Table 2, when a resist pattern is formed using the resist composition of Example 1 to which the present invention is applied, the lithography properties are excellent, the coatability is also good, and the resist pattern during high temperature baking is It can be confirmed that the foaming of is suppressed.

Claims (7)

A resist composition that generates acid upon exposure and whose solubility in a developer changes due to the action of the acid,
a polymer compound (A1) having a structural unit (a10) represented by the following general formula (a10-1) and a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid;
An acid generator (B1) represented by the following general formula (b1) (provided that the cation moiety is represented by the following general formula (ca-XB) and the anion moiety is represented by the following chemical formula (an-ZC1). anion, an anion represented by the following chemical formula (an-ZC2) or an anion represented by the following chemical formula (an-ZC3)), and
contains
A resist composition having a solid content concentration of 30% by mass 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 a (n _ax1 +1) valent aromatic hydrocarbon group. n _ax1 is an integer of 1-3. R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ each independently represent an optionally substituted aryl group. Two or more of R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ may combine with each other to form a ring together with the sulfur atom in the formula. X ⁻ represents an anion represented by the following general formula (an-1). ]

[In the formula, R″ ¹⁰¹ is an optionally substituted aliphatic cyclic group, a group represented by each of the above formulas (r-hr-1) to (r-hr-6), or a substituted 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. v″ is an integer of 0 to 3, q″ is an integer of 1 to 20, and n″ is 0 or 1. * indicates a bond.]

[In formula (ca-XB), each R 1 ^XB is independently an unsubstituted aryl group, an alkyl-substituted aryl group, an aryl-substituted aryl group, an arylthio-substituted aryl group, or an aryloxy-substituted aryl group. ] 2. The resist composition according to claim 1, wherein X 1 ⁻ in the general formula (b1) is an anion represented by the following chemical formula (an-1-1).

at least one of R ²⁰¹¹ , R ²⁰²¹ and R ²⁰³¹ in the general formula (b1) is an aryl group having a substituent;
The substituents include an alkyl group, a halogen atom, a halogenated alkyl group, a carbonyl group, a cyano group, an amino group, an aryl group, and the following general formulas (ca-r-1) to (ca-r-7), respectively. 3. The resist composition according to claim 1, which is one or more selected from the group consisting of the groups represented by:

[In the formula, each R′ ²⁰¹ is independently a hydrogen atom, an optionally substituted cyclic group, an optionally substituted chain alkyl group, or a substituted is a chain alkenyl group that may be ] 4. The resist composition according to any one of claims 1 to 3, wherein the polymer compound (A1) has a concentration of 90% by mass or more in the total solid content of the resist composition. 5. The resist composition according to claim 1, wherein the polymer compound (A1) has a weight average molecular weight of 5,000 to 20,000. Step (i) of forming a resist film on a support using the resist composition according to any one of claims 1 to 5, step (ii) of exposing the resist film, and after the exposure A resist pattern forming method, comprising a step (iii) of developing a resist film to form a resist pattern. 7. The method of forming a resist pattern according to claim 6, wherein in said step (ii), said resist film is irradiated with a KrF excimer laser beam.