JP6709711B2 - Resist composition, method for forming resist pattern and polymer compound - Google Patents

Description

The present invention relates to a resist composition, a resist pattern forming method and a polymer compound.

The technique of forming a fine pattern on a substrate and processing the lower layer of the pattern by using this as a mask (pattern forming technique) is widely adopted in the manufacture of semiconductor elements and liquid crystal display elements. The fine pattern is usually made of an organic material and is formed by a technique such as a lithography method or a nanoimprint method. For example, in the lithography method, a resist film containing a base material component such as a resin is used to form a resist film on a support such as a substrate, and the resist film is selected by radiation such as light or an electron beam. The step of forming a resist pattern of a predetermined shape on the resist film is performed by performing a static exposure and a developing process. Then, using the resist pattern as a mask, a semiconductor element or the like is manufactured through a step of processing the substrate by etching.
The resist material is classified into a positive type and a negative type. A resist material in which the solubility of an exposed portion in a developing solution is increased is referred to as a positive type, and a resist material in which the exposed portion is less soluble in a developing solution is referred to as a negative type. .
As the developing solution, an alkaline aqueous solution (alkali developing solution) such as tetramethylammonium hydroxide (TMAH) aqueous solution is usually used. Further, a developer containing an organic solvent such as an aromatic organic solvent, an aliphatic hydrocarbon organic solvent, an ether organic solvent, a ketone organic solvent, an ester organic solvent, an amide organic solvent, or an alcohol organic solvent. (Organic developer) is also used as a developer.

In recent years, advances in lithography technology have led to rapid miniaturization of patterns.
As a method of miniaturization, generally, the wavelength of an exposure light source is shortened (increased in energy). Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but now, mass production of semiconductor elements using KrF excimer laser or ArF excimer laser has started. Further, EB (electron beam), EUV (extreme ultraviolet ray), X-ray, etc. having a shorter wavelength (high energy) than these excimer lasers are also being studied.

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

Conventionally, a resin (base resin) is mainly used as a base material component of a chemically amplified resist composition. Currently, as a base resin for a chemically amplified resist composition used in ArF excimer laser lithography and the like, it has a structural unit derived from a (meth)acrylic acid ester in its main chain because of its excellent transparency at around 193 nm. Resin (acrylic resin) is the mainstream.

Here, “(meth)acrylic acid” means one 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. The “(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. The “(meth)acrylate” means one 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.

The base resin of the chemically amplified resist composition generally has a plurality of types of structural units in order to improve the lithographic properties and the like. For example, a structural unit having an lactone structure, a structural unit having a polar group such as a hydroxyl group, and the like are used together with a structural unit having an acid-decomposable group that decomposes by the action of an acid generated from an acid generator to generate an alkali-soluble group (See, for example, Patent Document 1). When the base resin is an acrylic resin, as the acid-decomposable group, a carboxy group in (meth)acrylic acid or the like is generally protected with an acid-dissociable group such as a tertiary alkyl group or an acetal group. Things are used.

A positive-type chemically amplified resist composition, that is, a positive-type development process in which a chemically-amplified resist composition whose solubility in an alkali developing solution increases by exposure and an alkali developing solution are combined is a negative-type chemically amplified resist composition. Compared to a negative development process in which a resist composition and an alkali developing solution are combined, there are advantages such that the structure of the photomask can be simplified and the characteristics of the formed pattern are excellent. Therefore, at present, a positive development process in which a positive chemically amplified resist composition and an alkaline developer are combined is mainly used for forming a fine pattern.
When the positive development process is applied, when the resist film obtained by applying such a positive chemically amplified resist composition onto a support is selectively exposed, the exposed portion of the resist film becomes a base resin. The acid-decomposable group inside decomposes by the action of the acid generated from the acid generator, etc., and changes from slightly soluble to soluble in the alkali developing solution, while the unexposed part of the resist film remains slightly soluble in alkali Therefore, by developing with an alkali developing solution, a dissolution contrast can be provided between the exposed portion and the unexposed portion, and a positive resist pattern can be formed.

A method of forming a resist pattern (negative resist pattern) by selectively dissolving and removing a region having low optical intensity is also useful for forming a fine pattern. As a method for forming this negative resist pattern, a chemically amplified resist composition used in the above-mentioned positive development process which is the mainstream, and a developing solution containing an organic solvent (organic developing solution) are combined. Negative development processes are known.
Further, conventionally, for the purpose of improving the lithographic properties and the like, for example, an acid-decomposable group having a specific structure (that is, an acid-decomposable group having a tertiary carbon atom to which an aliphatic hydrocarbon group having an ether bond is bonded) is included. A chemically amplified resist composition using a polymer compound having a structural unit as a base resin has been proposed (see Patent Document 2).

JP, 2003-241385, A JP, 2005-169843, A

Along with the ever-increasing performance and miniaturization of electronic devices, further improvement in lithography characteristics and resist pattern shape is required in pattern formation when manufacturing semiconductor elements and the like. However, there is still room for improvement in the shape of the resist pattern formed using the conventional resist composition, and there is a demand for further improvement in sensitivity, lithographic properties, and the like.
The present invention has been made in view of the above circumstances, and a novel polymer compound useful as a substrate component for a resist composition, a resist composition containing the polymer compound, and the resist composition. An object is to provide a used resist pattern forming method.

In order to solve the above problems, the present invention adopts the following configurations.
That is, the first aspect of the present invention is a resist composition in which an acid is generated by exposure and the solubility in a developing solution is changed by the action of an acid, and the solubility in a developing solution is changed by the action of an acid. The base material component (A) contains a polymer compound (A1) having a structural unit (a0) represented by the following general formula (a0-1). And a resist composition.

［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^０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_ａ０は、０〜２の整数である。Ｒａ^００は、一般式（ａ０−ｒ１−１）で表される酸解離性基である。Ｒａ^０１は、置換基を有していてもよい炭化水素基である。Ｒａ^０２は、置換基を有していてもよい炭化水素基である。Ｒａ^０１とＲａ^０２とは相互に結合して、環構造を形成してもよい。Ｙａ^０は、第４級炭素原子である。Ｒａ^０３１、Ｒａ^０３２及びＲａ^０３３は、それぞれ独立に、置換基を有していてもよい炭化水素基である。但し、Ｒａ^０３１、Ｒａ^０３２及びＲａ^０３３のうちの１つ以上は、少なくとも極性基を有する炭化水素基である。＊は、結合手であることを表す。］

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Va ⁰ is a divalent hydrocarbon group which may have an ether bond. _na0 is an integer of 0-2. Ra ⁰⁰ is an acid dissociable group represented by the general formula (a0-r1-1). Ra ⁰¹ is a hydrocarbon group which may have a substituent. Ra ⁰² is a hydrocarbon group which may have a substituent. Ra ⁰¹ and Ra ⁰² may be bonded to each other to form a ring structure. Ya ⁰ is a quaternary carbon atom. Ra ⁰³¹ , Ra ⁰³² and Ra ⁰³³ are each independently a hydrocarbon group which may have a substituent. However, one or more of Ra ⁰³¹ , Ra ^032, and Ra ⁰³³ is a hydrocarbon group having at least a polar group. * Represents a bond. ]

A second aspect of the present invention is a step of forming a resist film on the support using the resist composition of the first aspect, a step of exposing the resist film, and a step of developing the resist film after the exposure. And a resist pattern forming method.

A third aspect of the present invention is a polymer compound having a structural unit (a0) represented by general formula (a0-1) shown below.

［式中、Ｒは、水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基である。Ｖａ^０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_ａ０は、０〜２の整数である。Ｒａ^００は、一般式（ａ０−ｒ１−１）で表される酸解離性基である。Ｒａ^０１は、置換基を有していてもよい炭化水素基である。Ｒａ^０２は、置換基を有していてもよい炭化水素基である。Ｒａ^０１とＲａ^０２とは相互に結合して、環構造を形成してもよい。Ｙａ^０は、第４級炭素原子である。Ｒａ^０３１、Ｒａ^０３２及びＲａ^０３３は、それぞれ独立に、置換基を有していてもよい炭化水素基である。但し、Ｒａ^０３１、Ｒａ^０３２及びＲａ^０３３のうちの１つ以上は、少なくとも極性基を有する炭化水素基である。＊は、結合手であることを表す。］

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Va ⁰ is a divalent hydrocarbon group which may have an ether bond. _na0 is an integer of 0-2. Ra ⁰⁰ is an acid dissociable group represented by the general formula (a0-r1-1). Ra ⁰¹ is a hydrocarbon group which may have a substituent. Ra ⁰² is a hydrocarbon group which may have a substituent. Ra ⁰¹ and Ra ⁰² may be bonded to each other to form a ring structure. Ya ⁰ is a quaternary carbon atom. Ra ⁰³¹ , Ra ⁰³² and Ra ⁰³³ are each independently a hydrocarbon group which may have a substituent. However, one or more of Ra ⁰³¹ , Ra ^032, and Ra ⁰³³ is a hydrocarbon group having at least a polar group. * Represents a bond. ]

According to the resist composition and the method for forming a resist pattern of the present invention, the sensitivity can be further enhanced and the resist pattern shape can be further improved.
INDUSTRIAL APPLICABILITY The polymer compound of the present invention is useful as a resin for a resist composition in that the sensitivity can be further increased in resist pattern formation and the resist pattern shape can be further improved.

In the present specification and claims, the term “aliphatic” is defined as a relative concept to aromatic and means a group, compound or the like having no aromaticity.
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups. The same applies to the alkyl group in the alkoxy group.
Unless otherwise specified, the “alkylene group” includes linear, branched, and cyclic divalent saturated hydrocarbon groups.
The “halogenated alkyl group” is a group in which a part or all of hydrogen atoms of an alkyl group are substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
The "fluorinated alkyl group" or "fluorinated alkylene group" refers to a group in which some or all of the hydrogen atoms of the alkyl group or alkylene group are substituted with fluorine atoms.
The “constituent unit” means a monomer unit (monomer unit) that constitutes a polymer compound (resin, polymer, copolymer).
Be referred to as a "may have a substituent", the case of replacing a hydrogen atom (-H) a monovalent group, methylene group - when substituting a divalent radical (-CH ₂₎ Including both.
“Exposure” is a concept that includes all radiation irradiation.

The “structural unit derived from an acrylic ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylic ester.
The term "acrylate ester" is a compound in which the hydrogen atom of the carboxyl group terminal of acrylic acid _(CH 2 = CH-COOH) has been substituted with an organic group.
In the acrylate ester, the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. The substituent (R ^α0 ) for substituting the hydrogen atom bonded to the carbon atom at the α-position is an atom or a group other than a hydrogen atom, and is, for example, an alkyl group having 1 to 5 carbon atoms or a halogenated group having 1 to 5 carbon atoms. An alkyl group etc. are 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 group modified with its hydroxyl group are also included. Shall be included. The α-position carbon atom of the acrylic ester is the carbon atom to which the carbonyl group of acrylic acid is bonded, unless otherwise specified.
Hereinafter, an acrylate ester in which a hydrogen atom bonded to a carbon atom at the α-position is substituted with a substituent may be referred to as an α-substituted acrylate ester. In addition, the acrylic ester and the α-substituted acrylic ester may be collectively referred to as “(α-substituted) acrylic ester”.

"Styrene" is a concept including styrene and styrene in which the hydrogen atom at the α-position is substituted with another substituent such as an alkyl group or a halogenated alkyl group.
The "structural unit derived from styrene" and "structural unit derived from styrene derivative" mean a structural unit formed by cleavage of the ethylenic double bond of styrene or a styrene derivative.

The alkyl group as the α-position substituent is preferably a linear or branched alkyl group, 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.
The halogenated alkyl group as the α-position substituent is specifically a group in which a part or all of the hydrogen atoms of the above-mentioned “alkyl group as the α-position substituent” is replaced with a halogen atom. Be done. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is particularly preferable.
Specific examples of the hydroxyalkyl group as the α-position substituent include groups in which part or all of the hydrogen atoms of the above-mentioned “alkyl group as the α-position substituent” are substituted with hydroxyl groups. 1-5 are preferable and, as for the number of the hydroxyl groups in this hydroxyalkyl group, 1 is the most preferable.

(Resist composition)
The resist composition of the present embodiment is a resist composition which generates an acid upon exposure to light and whose solubility in a developing solution is changed by the action of an acid, and is a group whose solubility in a developing solution is changed by the action of an acid. The material component (A) (hereinafter, also referred to as “(A) component”) is contained.
When a resist film is formed using such a resist composition and the resist film is selectively exposed, an acid is generated in the exposed portion of the resist film, and the action of the acid causes the developer of component (A) to develop. While the solubility of the component (A) in the unexposed portion of the resist film does not change in the unexposed portion of the resist film, there is a difference in the solubility of the component between the exposed portion and the unexposed portion in the developing solution. Occurs. Therefore, when the resist film is developed, the exposed portion is dissolved and removed to form a positive resist pattern when the resist composition is a positive type, and the unexposed portion is dissolved when the resist composition is a negative type. The resist pattern is removed to form a negative resist pattern.
In the present specification, a resist composition in which an exposed portion is dissolved and removed to form a positive resist pattern is referred to as a positive resist composition, and a resist composition in which an unexposed portion is dissolved and removed to form a negative resist pattern. Is referred to as a negative resist composition.
The resist composition of this embodiment may be either a positive resist composition or a negative resist composition.
Further, the resist composition of the present embodiment may be for an alkali developing process in which an alkali developing solution is used for the developing treatment when forming a resist pattern, and a developing solution containing an organic solvent in the developing treatment (organic developing solution). May be used for a solvent developing process.

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

<(A) component>
In the present invention, the “base material component” is an organic compound having a film-forming ability, and an organic compound having a molecular weight of 500 or more is preferably used. When the molecular weight of the organic compound is 500 or more, the film forming ability is improved and, in addition, a nano-level resist pattern is easily formed.
The organic compound used as the base material component is roughly classified into a non-polymer and a polymer.
As the non-polymer, one having a molecular weight of 500 or more and less than 4000 is usually used. Hereinafter, the term "low molecular weight compound" means a non-polymer having a molecular weight of 500 or more and less than 4000.
As the polymer, one having a molecular weight of 1,000 or more is usually used. Hereinafter, the term "resin" or "polymer compound" refers to a polymer having a molecular weight of 1000 or more.
As the molecular weight of the polymer, the polystyrene-equivalent weight average molecular weight by GPC (gel permeation chromatography) is used.

When the resist composition of the present embodiment is a "negative resist composition for alkaline development process" that forms a negative resist pattern in an alkali development process, or a "solvent that forms a positive resist pattern in a solvent development process" In the case of the “positive resist composition for development process”, the component (A) is preferably a base component (A-2) soluble in an alkali developing solution (hereinafter referred to as “component (A-2)”). Is used, and a crosslinking agent component is further added. In such a resist composition, for example, when an acid is generated from the component (B) upon exposure, the acid acts to cause crosslinking between the component (A-2) and the crosslinking agent component, resulting in alkali development. Solubility in liquid decreases (solubility in organic developer increases). Therefore, in the formation of the resist pattern, when the resist film obtained by applying the resist composition on a support is selectively exposed, the exposed part is hardly soluble in an alkali developing solution (in an organic developing solution). On the other hand, the unexposed area remains soluble in the alkali developing solution (hardly soluble in the organic developing solution) while it does not change. Therefore, the negative resist pattern is formed by developing with the alkali developing solution. It At this time, a positive resist pattern is formed by developing with an organic developing solution.
As the preferable component (A-2), a resin soluble in an alkali developing solution (hereinafter referred to as "alkali-soluble resin") is used.
Examples of the alkali-soluble resin include α-(hydroxyalkyl)acrylic acid or an alkyl ester of α-(hydroxyalkyl)acrylic acid (preferably having 1 to 5 carbon atoms) disclosed in JP-A-2000-206994. A resin having a unit derived from at least one selected from the group consisting of alkyl esters; disclosed in US Pat. No. 6,949,325, wherein a hydrogen atom bonded to a carbon atom at the α-position having a sulfonamide group is substituted with a substituent. Acrylic resin or polycycloolefin resin which may be present; U.S. Pat. No. 6,949,325, JP-A-2005-336452, JP-A-2006-317803. An acrylic resin in which a hydrogen atom bonded to an atom may be substituted with a substituent; a polycycloolefin resin having a fluorinated alcohol, which is disclosed in JP 2006-259582 A, is a good resist with little swelling. It is preferable because a pattern can be formed.
It should be noted that the α-(hydroxyalkyl)acrylic acid is an acrylic acid in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent, and hydrogen is present at the carbon atom at the α-position to which a carboxy group is bonded. One or both of acrylic acid having an atom bonded thereto and α-hydroxyalkylacrylic acid having a hydroxyalkyl group (preferably a hydroxyalkyl group having 1 to 5 carbon atoms) bonded to the α-position carbon atom. ..
As the cross-linking agent component, for example, usually, an amino-based cross-linking agent such as glycoluril having a methylol group or an alkoxymethyl group, a melamine-based cross-linking agent, etc. are preferably used because a good resist pattern with less swelling can be formed. The compounding amount of the cross-linking agent component is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the alkali-soluble resin.

When the resist composition of the present embodiment is a “positive resist composition for an alkali developing process” which forms a positive resist pattern in an alkali developing process, or a “solvent which forms a negative resist pattern in a solvent developing process. In the case of the “negative resist composition for development process”, the component (A) is preferably a base component (A-1) whose polarity is increased by the action of an acid (hereinafter referred to as “component (A-1)”). ) Is used. By using the component (A-1), the polarity of the base material component changes before and after the exposure, so that good development contrast can be obtained not only in the alkali developing process but also in the solvent developing process.
When an alkali development process is applied, the component (A-1) is poorly soluble in an alkali developing solution before exposure, and, for example, when an acid is generated from the component (B) by exposure, the action of the acid causes The polarity is increased and the solubility in an alkaline developer is increased. Therefore, in the formation of a resist pattern, when a resist film obtained by coating the resist composition on a support is selectively exposed, the exposed portion changes from poorly soluble to soluble in an alkali developing solution. Since the unexposed area remains sparingly soluble in alkali, it is subjected to alkali development to form a positive resist pattern.
On the other hand, when a solvent development process is applied, the component (A-1) has a high solubility in an organic developing solution before exposure, and when an acid is generated by exposure, it has a high polarity due to the action of the acid. Solubility in organic developer decreases. Therefore, in the formation of a resist pattern, when a resist film obtained by coating the resist composition on a support is selectively exposed, the exposed portion changes from soluble to slightly soluble in an organic developer. On the other hand, since the unexposed area remains soluble and does not change, by developing with an organic developer, contrast can be provided between the exposed area and the unexposed area, and a negative resist pattern is formed.

In the resist composition of this embodiment, the component (A) is preferably the component (A-1). That is, the resist composition of the present embodiment is a "positive resist composition for an alkali developing process" that forms a positive resist pattern in an alkali developing process, or a "solvent developing method" that forms a negative resist pattern in a solvent developing process. It is preferably a “negative resist composition for process”.

The component (A) used in the resist composition of the present embodiment is a polymer compound (A1) having a structural unit (a0) represented by general formula (a0-1) (hereinafter referred to as “component (A1)”). )including.
As the component (A), at least the component (A1) is used, and other polymer compounds and/or low molecular compounds may be used in combination with the component (A1). When the component (A-1) is used as the component (A), the component (A-1) contains the component (A1).

Component (A1) The component (A1) is a polymer compound having the structural unit (a0) represented by general formula (a0-1) and, if necessary, other structural units.

<<Structural unit (a0)>>
The structural unit (a0) is a structural unit represented by general formula (a0-1) shown below.

［式中、Ｒは、水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基である。Ｖａ^０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_ａ０は、０〜２の整数である。Ｒａ^００は、一般式（ａ０−ｒ１−１）で表される酸解離性基である。］

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Va ⁰ is a divalent hydrocarbon group which may have an ether bond. _na0 is an integer of 0-2. Ra ⁰⁰ is an acid dissociable group represented by the general formula (a0-r1-1). ]

In the above formula (a0-1), R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms.
The alkyl group having 1 to 5 carbon atoms in R is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specifically, methyl group, ethyl group, propyl group, isopropyl group, n- Examples thereof include a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group and a neopentyl group.
The halogenated alkyl group having 1 to 5 carbon atoms in R is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is particularly preferable.
As R, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms is preferable, a hydrogen atom or a methyl group is more preferable because of industrial availability, and a methyl group is preferable. More preferable.

In the formula (a0-1), Va ⁰ is a divalent hydrocarbon group which may have an ether bond.
The divalent hydrocarbon group for Va ⁰ may be either an aliphatic hydrocarbon group or an aromatic hydrocarbon group.

The aliphatic hydrocarbon group as the divalent hydrocarbon group in Va ⁰ may be saturated or unsaturated, and is usually preferably saturated.
Specific examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, and an aliphatic hydrocarbon group containing a ring in the structure.

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

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

The aromatic hydrocarbon group as the divalent hydrocarbon group in Va ⁰ 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, further preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and most preferably 6 to 10 carbon atoms. . However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic ring included in the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; some of the carbon atoms constituting the aromatic hydrocarbon ring are hetero. Aromatic heterocycles substituted with atoms may be mentioned. Examples of the hetero atom in the aromatic heterocycle include an oxygen atom, a sulfur atom and a nitrogen atom.
Specific examples of the aromatic hydrocarbon group include a group obtained by removing two hydrogen atoms from the aromatic hydrocarbon ring (arylene group); a group obtained by removing one hydrogen atom from the aromatic hydrocarbon ring (aryl group). Group in which one of the hydrogen atoms of () is substituted with an alkylene group (for example, arylalkyl such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group). Group in which one hydrogen atom is further removed from the aryl group in the group) and the like. The alkylene group (alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

In the formula (a0-1), _na0 is an integer of 0 to 2, preferably 0 or 1, and more preferably 0.

In the formula (a0-1), Ra ⁰⁰ is an acid dissociable group represented by the following general formula (a0-r1-1). Such acid-dissociable group includes a quaternary carbon atom (Ya ^0), and the polar group is a functional group having the carbonyl group in formula (a0-1) [-C (= O ) -O- ], the oxy group (—O—) side is protected. The “acid-dissociable group” here has an acid-dissociable property in which a bond between the acid-dissociable group and an oxygen atom (O) adjacent to the acid-dissociable group can be cleaved by the action of an acid. When the acid dissociable group is dissociated by the action of an acid, 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. Due to the increase in polarity, the solubility in the developing solution relatively changes, the solubility increases when the developing solution is an alkaline developing solution, and the solubility changes when the developing solution is an organic developing solution. Decrease.

［式中、Ｒａ^０１は、置換基を有していてもよい炭化水素基である。Ｒａ^０２は、置換基を有していてもよい炭化水素基である。Ｒａ^０１とＲａ^０２とは相互に結合して、環構造を形成してもよい。Ｙａ^０は、第４級炭素原子である。Ｒａ^０３１、Ｒａ^０３２及びＲａ^０３３は、それぞれ独立に、置換基を有していてもよい炭化水素基である。但し、Ｒａ^０３１、Ｒａ^０３２及びＲａ^０３３のうちの１つ以上は、少なくとも極性基を有する炭化水素基である。＊は、結合手であることを表す（以下本明細書において同じ）。］

[In the formula, Ra ⁰¹ is a hydrocarbon group which may have a substituent. Ra ⁰² is a hydrocarbon group which may have a substituent. Ra ⁰¹ and Ra ⁰² may be bonded to each other to form a ring structure. Ya ⁰ is a quaternary carbon atom. Ra ⁰³¹ , Ra ⁰³² and Ra ⁰³³ are each independently a hydrocarbon group which may have a substituent. However, at least one of Ra ⁰³¹ , Ra ^032, and Ra ⁰³³ is a hydrocarbon group having at least a polar group. * Represents a bond (hereinafter the same in the present specification). ]

In the formula (a0-r1-1), * represents a bond that bonds to the oxy group (—O—) of the carbonyloxy group [—C(═O)—O—] in the formula (a0-1). is there.

In the formula (a0-r1-1), Ra ⁰¹ is a hydrocarbon group which may have a substituent. Ra ⁰² is a hydrocarbon group which may have a substituent. Ra ⁰¹ and Ra ⁰² may be bonded to each other to form a ring structure.
As the hydrocarbon group for Ra ⁰¹ and Ra ⁰² , each independently, a linear or branched alkyl group, a linear or cyclic alkenyl group, or a cyclic hydrocarbon group can be mentioned.

The linear alkyl group in Ra ⁰¹ and Ra ⁰² 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 thereof include a methyl group, an ethyl group, an n-propyl group, an n-butyl group and an n-pentyl group. Among these, a methyl group, an ethyl group or an n-butyl group is preferable, and a methyl group or an ethyl group is more preferable.
The branched chain alkyl group in Ra ⁰¹ and Ra ⁰² preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specific examples thereof include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group and a 2,2-dimethylbutyl group, and an isopropyl group is preferable.
The chain or cyclic alkenyl group for Ra ⁰¹ and Ra ⁰² is preferably an alkenyl group having 2 to 10 carbon atoms.

The cyclic hydrocarbon group in Ra ⁰¹ and Ra ⁰² may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and may be a polycyclic group or a monocyclic group.
The aliphatic hydrocarbon group which is a monocyclic group is preferably a group obtained by removing one hydrogen atom from monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof 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. Examples thereof include adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.

The aromatic hydrocarbon group in Ra ⁰¹ and Ra ⁰² is a hydrocarbon group having at least one aromatic ring. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The carbon number of the aromatic ring is preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and particularly preferably 6 to 12. Specific examples of the aromatic ring include an aromatic hydrocarbon ring such as benzene, naphthalene, anthracene, and phenanthrene; Can be mentioned. Examples of the hetero atom in the aromatic heterocycle include an oxygen atom, a sulfur atom and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring. Specific examples of the aromatic hydrocarbon group include a group (aryl group or heteroaryl group) obtained by removing one hydrogen atom from the aromatic hydrocarbon ring or aromatic heterocycle; aromatic containing two or more aromatic rings. A group in which one hydrogen atom is removed from a compound (for example, biphenyl, fluorene, etc.); A group in which one of the hydrogen atoms of the aromatic hydrocarbon ring or aromatic heterocycle is substituted with an alkylene group (for example, benzyl group, phenethyl group) , An arylalkyl group such as a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, a 2-naphthylethyl group) and the like. The alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle has preferably 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

When the hydrocarbon group represented by Ra ⁰¹ and Ra ⁰² above is substituted, examples of the substituent include a hydroxy group, a carboxy group, a halogen atom (fluorine atom, chlorine atom, bromine atom, etc.), alkoxy. Examples thereof include groups (methoxy group, ethoxy group, propoxy group, butoxy group, etc.), alkyloxycarbonyl group and the like.

In the formula (a0-r1-1), Ra ⁰¹ and Ra ⁰² may be bonded to each other to form a ring structure.
Examples of the ring structure formed by Ra ⁰¹ and Ra ⁰² include an alicyclic hydrocarbon group, a condensed ring of an alicyclic hydrocarbon and an aromatic hydrocarbon, and the like. The ring structure formed by Ra ⁰¹ and Ra ⁰² may have a hetero atom.

The alicyclic hydrocarbon group formed by Ra ⁰¹ and Ra ⁰² may be a polycyclic group or a monocyclic group.
The alicyclic hydrocarbon group which is a monocyclic group is preferably a group obtained by removing one hydrogen atom from monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof 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. Examples thereof include adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.

In the condensed ring formed by Ra ⁰¹ and Ra ⁰² , the alicyclic hydrocarbon moiety may be monocyclic or polycyclic, and the aromatic hydrocarbon moiety may be monocyclic or polycyclic.
This fused ring may have a substituent. Examples of this substituent include a methyl group, an ethyl group, a propyl group, a hydroxy group, a hydroxyalkyl group, a carboxy group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, etc.), an alkoxy group (a methoxy group, an ethoxy group, Propoxy group, butoxy group, etc.), acyl group, alkyloxycarbonyl group, alkylcarbonyloxy group and the like.
Specific examples of the condensed ring formed by Ra ⁰¹ and Ra ⁰² are shown below.

In the formula (a0-r1-1), Ra ⁰¹ and Ra ⁰² are preferably bonded to each other to form a ring structure because Ra ⁰¹ and Ra ⁰² are more likely to enhance the lithographic properties, and are bonded to each other to form an alicyclic ring. More preferably, it forms a formula hydrocarbon group.

In the formula (a0-r1-1), Ya ⁰ is a quaternary carbon atom. That is, there are four adjacent carbon atoms bonded to Ya ⁰ (carbon atom).

In the formula (a0-r1-1), Ra ⁰³¹ , Ra ⁰³² and Ra ⁰³³ are each independently a hydrocarbon group which may have a substituent.
The optionally substituted hydrocarbon group for Ra ⁰³¹ , Ra ⁰³² and Ra ⁰³³ may have a substituent for Ra ⁰¹ and Ra ⁰² in the formula (a0-r1-1). The same as a good hydrocarbon group can be mentioned. Among these, the hydrocarbon group ^optionally having a substituent in Ra ⁰³¹ , Ra ⁰³² and Ra ⁰³³ is preferably a linear or branched alkyl group optionally having a substituent, and A chain alkyl group is more preferable.

However, one or more of Ra ⁰³¹ , Ra ^032, and Ra ⁰³³ is a hydrocarbon group having at least a polar group.
The “hydrocarbon group having a polar group” means that a polar group is present between hydrocarbon chains (between carbon atoms), or at least one hydrogen atom constituting the hydrocarbon group is substituted with a polar group. It includes any of the above.
The "hydrocarbon group having a polar group" is preferably a functional group represented by the following general formula (a0-p1).

［式中、Ｒａ^０４は、炭素数２〜１２の２価の炭化水素基を表す。Ｒａ^０５は、ヘテロ原子を含む２価の連結基を表す。Ｒａ^０６は、炭素数１〜１２の１価の炭化水素基を表す。ｎ_ｐ０は、１〜６の整数である。］

[In the formula, Ra ⁰⁴ represents a divalent hydrocarbon group having 2 to 12 carbon atoms. Ra ⁰⁵ represents a divalent linking group containing a hetero atom. Ra ⁰⁶ represents a monovalent hydrocarbon group having 1 to 12 carbon atoms. n _p0 is an integer of 1 to 6. ]

In the formula (a0-p1), Ra ⁰⁴ represents a divalent hydrocarbon group having 2 to 12 carbon atoms.
The number of carbon atoms of ra ⁰⁴ is 2 to 12, 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms, more preferably 2 to 4 carbon atoms, 2 carbon atoms being particularly preferred.
The hydrocarbon group for Ra ⁰⁴ is preferably a chain or cyclic aliphatic hydrocarbon group, and more preferably a chain hydrocarbon group.
Examples of Ra ⁰⁴ include ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1, 7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, etc. A linear alkanediyl group of: propane-1,2-diyl group, 1-methylbutane-1,3-diyl group, 2-methylpropane-1,3-diyl group, pentane-1,4-diyl group, 2 -Branched alkanediyl group such as methylbutane-1,4-diyl group; cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclooctane-1 A cycloalkanediyl group such as a 5,5-diyl group; a multi-group such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, adamantane-2,6-diyl group Examples thereof include cyclic divalent alicyclic hydrocarbon groups.
Among the above, an alkanediyl group is preferable, and a linear alkanediyl group is more preferable.

In the formula (a0-p1), Ra ⁰⁵ represents a divalent linking group containing a hetero atom.
Examples of Ra ⁰⁵ include -O-, -C(=O)-O-, -C(=O)-, -OC(=O)-O-, and -C(=O)-NH-. , -NH-, -NH-C(=NH)- (H may be substituted with a substituent such as an alkyl group and an acyl group), -S-, -S(=O) _2- , -. S(=O) _2- O- and the like can be mentioned.
Among these, -O-, -C(=O)-O-, -C(=O)-, and -OC(=O)-O- are preferable from the viewpoint of solubility in a developing solution, and- O- and -C(=O)- are particularly preferable.

In the formula (a0-p1), Ra ⁰⁶ represents a monovalent hydrocarbon group having 1 to 12 carbon atoms.
The carbon number of Ra ⁰⁶ is 1 to 12, and from the viewpoint of solubility in a developing solution, 1 to 8 carbon atoms are preferable, 1 to 5 carbon atoms are more preferable, 1 to 3 carbon atoms are further preferable, and carbon number is 1 or 2 is particularly preferable, and 1 is the most preferable.

Examples of the hydrocarbon group for Ra ⁰⁶ include a chain hydrocarbon group or a cyclic hydrocarbon group, or a hydrocarbon group combining a chain and a ring.
Examples of the chain hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n Examples include -heptyl group, 2-ethylhexyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group and n-dodecyl group.

The cyclic hydrocarbon group may be an alicyclic hydrocarbon group or an aromatic hydrocarbon group.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon group may be, for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, or a methyl group. Examples thereof include cycloalkyl groups such as cyclohexyl group, dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, cycloheptyl group and cyclodecyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a 2-alkyladamantan-2-yl group, a 1-(adamantan-1-yl)alkane-1-yl group, and norbornyl. Group, methylnorbornyl group, isobornyl group and the like.
Examples of the aromatic hydrocarbon group include phenyl group, naphthyl group, anthryl group, p-methylphenyl group, p-tert-butylphenyl group, p-adamantylphenyl group, tolyl group, xylyl group, cumenyl group and mesityl group. , Biphenyl group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group and the like.

From the viewpoint of solubility in a developing solution, Ra ⁰⁶ is preferably a chain hydrocarbon group, more preferably an alkyl group, and even more preferably a straight chain alkyl group.

In the formula (a0-p1), n _p0 is an integer of 1 to 6, preferably an integer of 1 to 3, more preferably 1 or 2, and even more preferably 1.

Specific examples of the hydrocarbon group having at least a polar group are shown below.
In the following formulas, * is a bond that bonds to the quaternary carbon atom (Ya ⁰ ).

In the above formula (a0-r1-1), the number of hydrocarbon groups having at least a polar group among Ra ⁰³¹ , Ra ⁰³² and Ra ⁰³³ is 1 or more. It may be appropriately determined in consideration of the solubility of, for example, one or two of Ra ⁰³¹ , Ra ⁰³² and Ra ⁰³³ is preferable, and one is particularly preferable.

The hydrocarbon group having at least the polar group may have a substituent other than the polar group. Examples of this substituent include a halogen atom (fluorine atom, chlorine atom, bromine atom, etc.) and a halogenated alkyl group having 1 to 5 carbon atoms.

In the above formula (a0-1), Ra ⁰⁰ is preferably an acid dissociable group represented by the following general formula (a0-r1-10).

［式中、Ｙａａは炭素原子である。Ｘａａは、Ｙａａと共に環状の炭化水素基を形成する基である。Ｙａ^０は、第４級炭素原子である。Ｒａ^０３１１及びＲａ^０３２１は、それぞれ独立に、置換基を有していてもよい鎖状のアルキル基を表す。Ｒａ^０３３１は、上記一般式（ａ０−ｐ１）で表される官能基を表す。］

[In the formula, Yaa is a carbon atom. Xaa is a group that forms a cyclic hydrocarbon group together with Yaa. Ya ⁰ is a quaternary carbon atom. ^Ra0311 and ^Ra0321 each independently represent a chain alkyl group which may have a substituent. Ra ⁰³³¹ represents a functional group represented by the above general formula (a0-p1). ]

In the formula (a0-r1-10), the cyclic hydrocarbon group formed by Xaa together with Yaa is exemplified in the description of Ra ⁰¹ and Ra ⁰² in the formula (a0-r1-1). Examples thereof include the same groups as those obtained by further removing one or more hydrogen atoms from a cyclic hydrocarbon group.
Among these, an alicyclic hydrocarbon group is preferable as the cyclic hydrocarbon group formed by Xaa together with Yaa. The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group, and among them, the monocyclic group is more preferable.

The cyclic hydrocarbon group formed by Xaa together with Yaa may have a substituent. Examples of the substituent include a hydroxy group, a carboxy group, a halogen atom (fluorine atom, chlorine atom, bromine atom, etc.), an alkoxy group (methoxy group, ethoxy group, propoxy group, butoxy group, etc.), an alkyloxycarbonyl group, etc. Is mentioned.

In the formula ^{(a0-r1-10), Ra 0311} and ^{Ra 0321} each independently represent a good chain alkyl group which may have a substituent.
^Examples of the chain alkyl group in Ra ⁰³¹¹ and Ra ⁰³²¹ include the same as the straight chain or branched chain alkyl group in Ra ⁰¹ and Ra ⁰² . Among these, a linear alkyl group is preferable, the number of carbon atoms is preferably 1 to 5, a methyl group, an ethyl group or an n-butyl group is more preferable, and a methyl group or an ethyl group is further preferable.

Specific examples of the structural unit represented by the formula (a0-1) are shown below.
In each formula below, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

The structural unit (a0) contained in the component (A1) may be one type or two or more types.
The proportion of the structural unit (a0) in the component (A1) is preferably 10 to 70 mol% and more preferably 20 to 65 mol% based on the total (100 mol%) of all structural units constituting the component (A1). It is preferably 25 to 60 mol%, more preferably 30 to 50 mol%.
When the proportion of the structural unit (a0) is at least the lower limit value of the above-described preferred range, a resist pattern can be easily obtained, and sensitivity, in-plane uniformity of pattern dimensions (CDU), and circularity (Circularity) are obtained. The lithographic properties such as) are also improved. On the other hand, when it is at most the upper limit of the above preferred range, it becomes easy to balance with other structural units.

≪Other structural units≫
The component (A1) may have a structural unit other than the structural unit (a0) described above.
As the other structural unit, for example, a structural unit (a1) containing an acid-decomposable group whose polarity increases by the action of an acid (excluding the structural unit (a0)); a lactone-containing cyclic group, -SO ₂ -containing A structural unit (a2) containing a cyclic group or a carbonate-containing cyclic group; a structural unit (a3) containing a polar group-containing aliphatic hydrocarbon group (however, the structural unit (a0), the structural unit (a1) or the structural unit ( (excluding those corresponding to a2)); a structural unit (a4) containing an acid non-dissociable aliphatic cyclic group; a structural unit derived from styrene or a derivative thereof, and the like.

About the structural unit (a1):
In addition to the structural unit (a0), the component (A1) may further have a structural unit (a1) containing an acid-decomposable group whose polarity increases due to the action of an acid.

The “acid-decomposable group” is a group having acid-decomposability capable of cleaving at least a part of the bonds in the structure of the acid-decomposable group by the action of an acid.
Examples of the acid-decomposable group whose polarity increases by the action of an acid include groups that decompose to form a polar group by the action of an acid.
Examples of the polar group include a carboxy group, a hydroxyl group, an amino group, a sulfo group _(-SO 3 H) and the like. Among these, a polar group containing -OH in the structure (hereinafter sometimes referred to as "OH-containing polar group") is preferable, a carboxy group or a hydroxyl group is more preferable, and a carboxy group is particularly preferable.
More specific examples of the acid-decomposable group include a group in which the polar group is protected with an acid-dissociable group (for example, a group in which a hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).
Here, the “acid-dissociable group” is a group having an acid-dissociable group capable of cleaving a bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group by the action of (i) an acid, Alternatively, (ii) after a part of the bond is cleaved by the action of an acid, a decarboxylation reaction further occurs, whereby the bond between the acid dissociable group and an atom adjacent to the acid dissociable group is cleaved. To obtain both groups.
The acid-dissociable group constituting the acid-decomposable group needs to be a group having a lower polarity than the polar group generated by the dissociation of the acid-dissociable group, which allows the acid-dissociable group to act under the action of an acid. 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. Due to the increase in polarity, the solubility in the developing solution relatively changes, the solubility increases when the developing solution is an alkaline developing solution, and the solubility changes when the developing solution is an organic developing solution. Decrease.

The acid dissociable group in the structural unit (a1) excludes the acid dissociable group represented by the above general formula (a0-r1-1), and has hitherto been used as a base resin for a chemically amplified resist. The thing proposed as an acid dissociatable group is mentioned.
Specifically, "acetal-type acid dissociable group" and "tertiary alkyl ester-type acid dissociable group" described below are proposed as the acid-dissociable group of the base resin for the chemically amplified resist. , "Tertiary alkyloxycarbonyl acid dissociable groups".

-Acetal-type acid dissociable group:
Examples of the acid dissociable group that protects a carboxy group or a hydroxyl group among the polar groups include, 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 are some cases).

［式中、Ｒａ’^１、Ｒａ’^２は水素原子またはアルキル基であり、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 is bonded to either Ra′ ¹ or Ra′ ² to form a ring. May be formed. ]

In the formula (a1-r-1), at least one of Ra′ ¹ and Ra′ ² is preferably a hydrogen atom, and more preferably both are hydrogen atoms.
When Ra′ ¹ or Ra′ ² is an alkyl group, the alkyl group is the same as the alkyl group described as the substituent which may be bonded to the α-position carbon atom in the description of the α-substituted acrylate ester. The same thing is mentioned and a C1-C5 alkyl group is preferable. Specifically, a linear or branched alkyl group is preferable. 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. More preferably, a methyl group is particularly preferable.

In formula (a1-r-1), examples of the hydrocarbon group represented by Ra′ ³ include a linear or branched alkyl group and a cyclic hydrocarbon group.
The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4 and even more preferably 1 or 2. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an 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, and more preferably 3 to 5 carbon atoms. Specific examples thereof include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, a 1,1-diethylpropyl group and a 2,2-dimethylbutyl group, and an isopropyl group is preferable.

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.
The aliphatic hydrocarbon group which is a monocyclic group is preferably a group obtained by removing one hydrogen atom from monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof 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. Examples thereof include adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane and the like.

When the cyclic hydrocarbon group of Ra′ ³ is an aromatic hydrocarbon group, the aromatic hydrocarbon group is a hydrocarbon group having at least one aromatic ring.
The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n+2 π electrons, and may be monocyclic or polycyclic. The carbon number of the aromatic ring is preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and particularly preferably 6 to 12. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene, and phenanthrene; and aromatic heterocycles in which a part of carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms. Can be mentioned. Examples of the hetero atom in the aromatic heterocycle include an oxygen atom, a sulfur atom and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.
Specific examples of the aromatic hydrocarbon group for Ra′ ³ include a group (aryl group or heteroaryl group) obtained by removing one hydrogen atom from the aromatic hydrocarbon ring or aromatic heterocycle; two or more aromatic rings A group in which one hydrogen atom has been removed from an aromatic compound (for example, biphenyl, fluorene, etc.); , Phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, arylalkyl group such as 2-naphthylethyl group, etc.) and the like. The alkylene group bonded to the aromatic hydrocarbon ring or aromatic heterocycle has preferably 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

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

-Tertiary alkyl ester type acid dissociable group:
Among the polar groups, examples of the acid dissociable group that protects the carboxy group include acid dissociable groups represented by the following general formula (a1-r-2). In addition, among the acid dissociable groups represented by the following formula (a1-r-2), a group composed of an alkyl group may be hereinafter referred to as a “tertiary alkyl ester-type acid dissociable group” 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, Ra′ ^{4 to} Ra′ ⁶ are each a hydrocarbon group, and Ra′ ⁵ and Ra′ ⁶ may be bonded to each other to form a ring. ]

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

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

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

In formula (a1-r2-1), the alkyl group having 1 to ¹⁰ carbon atoms represented by Ra′ ¹⁰ is exemplified as the linear or branched alkyl group represented by Ra′ ³ in formula (a1-r-1). Groups are preferred. In the formula (a1-r2-1), the aliphatic cyclic group formed by Ra′ ¹¹ together with the carbon atom to which Ra′ ¹⁰ is bonded is a monocyclic group of Ra′ ³ in the formula (a1-r-1) or The groups mentioned as the aliphatic hydrocarbon group which is a polycyclic group are preferable.

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

Specific examples of the group represented by the formula (a1-r2-1) are shown below. * Indicates a bond (hereinafter the same in the present specification).

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

-Tertiary alkyloxycarbonyl acid dissociative group:
Examples of the acid dissociable group that protects the hydroxyl group among the polar groups include, for example, an acid dissociable group represented by the following general formula (a1-r-3) (hereinafter, for convenience, "tertiary alkyloxycarbonyl acid dissociable group"). It may be said that)).

［式中、Ｒａ’^７〜Ｒａ’^９はそれぞれアルキル基である。］

[In the formula, Ra′ ^{7 to} Ra′ ⁹ are each an alkyl group. ]

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

As the structural unit (a1), a structural unit derived from an acrylate ester in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent, a structural unit derived from acrylamide, hydroxystyrene or hydroxy. At least a part of hydrogen atoms in a hydroxyl group of a structural unit derived from a styrene derivative is protected by a substituent containing the acid-decomposable group, vinylbenzoic acid or a structural unit derived from a vinylbenzoic acid derivative- Examples include structural units in which at least a part of hydrogen atoms in C(=O)-OH are protected by a substituent containing the acid-decomposable group.

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

［式中、Ｒは水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基である。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り、ｎ_ａ１は０〜２であり、Ｒａ^１は上記式（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り、ｎ_ａ２は１〜３であり、Ｒａ^２は上記式（ａ１−ｒ−１）又は（ａ１−ｒ−３）で表される酸解離性基である。］

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

In the formula (a1-1), 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, 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. The halogenated alkyl group having 1 to 5 carbon atoms is a group in which some or all of the hydrogen atoms of the above alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is particularly preferable.
As R, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms is preferable, and a hydrogen atom or a methyl group is most preferable from the viewpoint of industrial availability.

In the formula (a1-1), the hydrocarbon group which may divalent have an ether bond Va ¹ is, Va ⁰ in formula (a0-1) is have an ether bond as a substituent It is the same as in the case of using a divalent hydrocarbon group which may be present.

In the formula (a1-2), the na ₂ +1 valent hydrocarbon group for Wa ¹ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity, may be saturated or unsaturated, and is usually preferably saturated. As the aliphatic hydrocarbon group, a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, or a linear or branched aliphatic hydrocarbon group Examples thereof include groups in which an aliphatic hydrocarbon group containing a ring in the structure is combined.
The n _a2 +1 valence is preferably 2 to 4, and more preferably 2 or 3.

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

The structural unit (a1) contained in the component (A1) may be one type or two or more types.
When the component (A1) has the structural unit (a1), the proportion of the structural unit (a1) in the component (A1) is from 1 to 50 mol% based on the total of all structural units constituting the component (A1). It is preferably 5 to 45 mol%, more preferably 5 to 30 mol%.
By setting the proportion of the structural unit (a1) to the lower limit or more, a resist pattern can be easily obtained, and lithography properties such as sensitivity, resolution, roughness improvement or EL margin are also improved. Also, by setting the content to the upper limit or less, it is possible to balance with other structural units.

Regarding the structural unit (a2):
In addition to the structural unit (a0), the component (A1) may further have a structural unit (a2) containing a lactone-containing cyclic group, a —SO ₂ — containing cyclic group or a carbonate containing cyclic group. ..
The lactone-containing cyclic group, the —SO ₂ — containing cyclic group or the carbonate containing cyclic group of the structural unit (a2) adheres to the substrate of the resist film when the component (A1) is used for forming the resist film. It is effective in enhancing the sex. Further, by having the structural unit (a2), the solubility of the resist film in an alkali developing solution is enhanced during development in the alkali developing process.

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

［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り；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、酸素原子又は硫黄原子である。ｎ’は０〜２の整数であり、ｍ’は０又は１である。］

Wherein, Ra ^'21 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, hydroxyl group, -COOR ", - OC (= O) R", a hydroxyalkyl group or a cyano 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. It is an alkylene group having 1 to 5 carbon atoms, which may contain (-S-), an oxygen atom or a sulfur atom. n′ is an integer of 0 to 2 and m′ is 0 or 1. ]

In the 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 thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group and a hexyl group. Among these, a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable.
As the alkoxy group for Ra′ ^21, an alkoxy group having 1 to 6 carbon atoms is preferable. The alkoxy group is preferably linear or branched. Specific examples thereof include groups in which an alkyl group mentioned as the alkyl group in Ra′ ²¹ and an oxygen atom (—O—) are linked.
Examples of the halogen atom in Ra' ²¹ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.
'Examples of the halogenated alkyl group for ^21, the Ra' Ra some or all of the hydrogen atoms of the alkyl group in ²¹ can be mentioned have been substituted with the aforementioned halogen atoms. As the halogenated alkyl group, a fluorinated alkyl group is preferable, and a perfluoroalkyl group is particularly preferable.

Ra '-COOR in ^{21 ", - OC (= O} ) R" in, R "is also hydrogen either is an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or -SO ₂ - containing cyclic group Is.
The alkyl group in 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. Specifically, a fluorine atom. Or a group in which one or more hydrogen atoms have been removed from a monocycloalkane that may or may not be substituted with a fluorinated alkyl group; polycycloalkanes such as bicycloalkane, tricycloalkane, and tetracycloalkane And a group in which one or more hydrogen atoms have been removed from the group, and more specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane and cyclohexane; adamantane, norbornane, isobornane, and trigroup. Examples thereof include groups in which one or more hydrogen atoms have been removed from polycycloalkane 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 for R″ is the same as the carbonate-containing cyclic group described below, and specifically, the groups represented by general formulas (ax3-r-1) to (ax3-r-3), respectively. Is mentioned.
The containing cyclic group, -SO ₂ below - - -SO ₂ in R "are the same as containing cyclic group, specifically the general formula (a5-r-1) ~ (a5-r-4) And the groups respectively represented by.
The hydroxyalkyl group for Ra′ ²¹ preferably has 1 to 6 carbon atoms, and specific examples thereof include a group 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 straight chain or a branched chain. An alkylene group is preferable, and examples thereof include 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 or carbon atom of the alkylene group. between atoms -O- or -S- can be mentioned a group intervening, for example, _{-O-CH 2 -, - CH} 2 -O-CH 2 -, - S-CH 2 -, - CH 2 -S-CH _2- etc. are mentioned. As A", a C1-C5 alkylene group or -O- is preferable, a C1-C5 alkylene group is more preferable, and a methylene group is the most preferable.

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

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

［式中、Ｒａ’^５１は、それぞれ独立に、水素原子、アルキル基、アルコキシ基、ハロゲン原子、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基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。］

Wherein, Ra ^'51 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, hydroxyl group, -COOR ", - OC (= O) R", a hydroxyalkyl group or a cyano It is a base. R "is a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or an -SO 2 _- containing cyclic group .A" is 1 number of oxygen atoms or carbon atoms which may contain a sulfur atom Is an alkylene group, 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″ represents the general formulas (a2-r-2), (a2-r-3), and (a2-r-5). It is similar to A" in the inside.
The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, —COOR″, —OC(═O)R″ and hydroxyalkyl group for Ra′ ⁵¹ are each represented by the general formula (a2-r-1) to (a2-r-1). The same as those mentioned in the description of Ra′ ^{21 in} a2-r-7) can be mentioned.
Specific examples of the groups represented by general formulas (a5-r-1) to (a5-r-4) are shown below. “Ac” in the formula represents an acetyl group.

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

［式中、Ｒａ’^ｘ３１は、それぞれ独立に、水素原子、アルキル基、アルコキシ基、ハロゲン原子、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基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。］

[In formula, ^Ra'x31 is each 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 cyano. It is a base. R "represents a hydrogen atom, an alkyl group, a lactone-containing cyclic group, a carbonate-containing cyclic group, or an -SO 2 _- containing cyclic group .A" good carbon atoms which may contain an oxygen atom or a sulfur atom 1 to 5 alkylene groups, oxygen atoms or sulfur atoms. 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″ represents the general formulas (a2-r-2), (a2-r-3), and (a2-r-5). It is similar to A" in the inside.
The alkyl group, alkoxy group, halogen atom, halogenated alkyl group, —COOR″, —OC(═O)R″ and hydroxyalkyl group for Ra′ ³¹ are each represented by the general formula (a2-r-1) to ( The same as those mentioned in the description of Ra′ ^{21 in} a2-r-7) can be mentioned.
Specific examples of the groups represented by general formulas (ax3-r-1) to (ax3-r-3) are shown below.

As the structural unit (a2), a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent is preferable.
The structural unit (a2) is preferably a structural unit represented by general formula (a2-1) shown below.

［式中、Ｒは、水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基である。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、−ＳＯ_２−含有環式基又はカーボネート含有環式基である。］

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. 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 does not become -CO-. Ra ²¹ is a lactone-containing cyclic group, a —SO ₂ — containing cyclic group or a carbonate containing cyclic group. ]

In the formula (a2-1), R is the same as above.
As R, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms is preferable, and a hydrogen atom or a methyl group is particularly preferable from the viewpoint of industrial availability.

In the formula (a2-1), the divalent linking group of Ya ²¹ is not particularly limited, but may be a divalent hydrocarbon group which may have a substituent, or a divalent linking group containing a hetero atom. Etc. are mentioned as a suitable thing.

Examples of the divalent hydrocarbon group for Ya ²¹ include the same groups as those described above for the divalent hydrocarbon group for Va ⁰ in formula (a0-1). Examples of the substituent that the divalent hydrocarbon group for Ya ²¹ may have include, for example, an alkyl group having 1 to 5 carbon atoms, an alkoxy group, a halogen atom, a halogenated alkyl group having 1 to 5 carbon atoms, and a hydroxyl group. , Carbonyl group and the like.

Preferred examples of the divalent linking group containing a hetero atom in Ya ²¹ include, for example, -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 and an acyl group), _{-S -, - S (= O} ) 2 -, - S (= O) 2 -O-, the formula ^{-Y 21 -O-Y 22 -,} - Y 21 -O -, - Y 21 -C (= ^{O) -O -, - C (} = O) -O-Y 21 -, - [Y 21 -C (= O) -O] m "-Y 22 -, - Y 21 -O-C (= O) A group represented by —Y ²² — or —Y ²¹ —S(═O) ₂ —O—Y ²² — [wherein, Y ²¹ and Y ²² may each independently have a substituent 2 It is a valent hydrocarbon group, O is an oxygen atom, and m″ is an integer of 0 to 3. ] Etc. are mentioned.
The divalent linking group containing a hetero atom is -C(=O)-NH-, -C(=O)-NH-C(=O)-, -NH-, -NH-C(=NH). In the case of −, 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.
Formula ^{-Y 21 -O-Y 22 -,} - Y 21 -O -, - Y 21 -C (= O) -O -, - C (= O) -O-Y 21 -, - [Y 21 - _{^{C (= O) -O] m}} "-Y 22 -, - Y 21 -O-C (= O) -Y 22 - or _{^{-Y 21 -S (= O) 2}} -O-Y 22 - in, Y ²¹ and Y ²² each independently represent a divalent hydrocarbon group which may have a substituent, and the divalent hydrocarbon group is mentioned in the description of the divalent linking group. (The divalent hydrocarbon group which may have a substituent).
As Y ²¹ , a linear aliphatic hydrocarbon group is preferable, a linear alkylene group is more preferable, a linear alkylene group having 1 to 5 carbon atoms is further preferable, and a methylene group or an ethylene group is particularly preferable. preferable.
As Y ²² , a linear or branched aliphatic hydrocarbon group is preferable, and a methylene group, an ethylene group or an alkylmethylene group is more preferable. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.
Formula _{^{- [Y 21 -C (= O}} ) -O] m "-Y 22 - In the group represented by, m" is an integer of 0 to 3, preferably an integer of 0 to 2, 0 Alternatively, 1 is more preferable, and 1 is particularly preferable. In other words, the formula ^- Examples of the group represented by the formula ^{-Y 21 -C (= O) -O} -Y 22 - - [Y 21 -C (= O) -O] m "-Y 22 represented by group is particularly preferred among them, the formula _{-. (CH 2) a '} -C (= O) -O- (CH 2) b' -. in the group represented by the formula in the formula, a 'is 1 It is an integer of 10, an integer of 1 to 8 is preferable, an integer of 1 to 5 is more preferable, 1 or 2 is further preferable, and 1 is most preferable.b'is an integer of 1 to 10 and 1 to 8 Is preferred, an integer from 1 to 5 is more preferred, 1 or 2 is even more preferred, and 1 is most preferred.

Ya ²¹ is preferably a single bond, an ester bond [—C(═O)—O—], an ether bond (—O—), a linear or branched alkylene group, or a combination thereof. ..

In the formula (a2-1), La ²¹ is —O—, —COO—, —CON(R′)—, —OCO—, —CONHCO— or —CONHCS—.
R'represents a hydrogen atom or a methyl group.
However, when La ²¹ is -O-, Ya ²¹ does not become -CO-.

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

The structural unit (a2) contained in the component (A1) may be one type or two or more types.
When the component (A1) has the structural unit (a2), the proportion of the structural unit (a2) is 1 to 70 mol% based on the total (100 mol%) of all the structural units constituting the component (A1). Is more preferable, 3 to 60 mol% is more preferable, and 5 to 50 mol% is further preferable.
When the proportion of the structural unit (a2) is at least the lower limit value of the above-mentioned preferred range, the effect of incorporating the structural unit (a2) is sufficiently obtained, while it is at most the upper limit value of the above-mentioned preferred range. And other structural units can be balanced, and various lithographic characteristics and pattern shapes are improved.

About the structural unit (a3):
The component (A1) may further have a structural unit (a3) containing a polar group-containing aliphatic hydrocarbon group in addition to the structural unit (a0) (provided that the above structural unit (a0), (Excluding those corresponding to either the unit (a1) or the structural unit (a2)).
When the component (A1) has the structural unit (a3), the hydrophilicity of the component (A) is increased, which contributes to improvement in resolution.

Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is replaced with a fluorine atom, and the like, and a hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and a cyclic aliphatic hydrocarbon group (cyclic group). The cyclic group may be a monocyclic group or a polycyclic group, and can be appropriately selected and used from, for example, a large number of groups proposed in resins for resist compositions for ArF excimer lasers. The cyclic group is preferably a polycyclic group, and more preferably has 7 to 30 carbon atoms.
Among them, a structural unit derived from an acrylate ester containing an aliphatic polycyclic group containing a hydroxyalkyl group in which a part of hydrogen atoms of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with a fluorine atom. Is more preferable. Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane, and the like. Specific examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, a group obtained by removing two or more hydrogen atoms from adamantane, a group obtained by removing two or more hydrogen atoms from norbornane, and a group obtained by removing two or more hydrogen atoms from tetracyclododecane are Industrially preferred.

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

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

[In the formula, R is the same as the above, j is an integer of 1 to 3, k is an integer of 1 to 3, t′ is an integer of 1 to 3, and l is an integer of 1 to 5. And s is an integer of 1 to 3. ]

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

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

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

The structural unit (a3) contained in the component (A1) may be one type or two or more types.
When the component (A1) has the structural unit (a3), the proportion of the structural unit (a3) is preferably 1 to 50 mol% based on the total of all structural units constituting the component (A1), It is more preferably from 1 to 40 mol%, further preferably from 3 to 30 mol%, particularly preferably from 10 to 20 mol%.
When the ratio of the structural unit (a3) is not less than the preferable lower limit value, the resolution is further improved in resist pattern formation. On the other hand, when the content is not more than the preferred upper limit, it becomes easy to balance with other structural units.

About the structural unit (a4):
The component (A1) may further have a structural unit (a4) containing an acid non-dissociable aliphatic cyclic group, in addition to the structural unit (a0).
When the component (A1) has the structural unit (a4), the dry etching resistance of the formed resist pattern is improved. Further, the hydrophobicity of the component (A) is increased. The improvement in hydrophobicity contributes to the improvement in resolution, resist pattern shape, etc., particularly in the case of a solvent development process.
The “acid non-dissociable cyclic group” in the structural unit (a4) means that when an acid is generated in the resist composition by exposure (for example, an acid is generated from the structural unit or the component (B) which generates an acid by exposure). A cyclic group that remains in the structural unit without being dissociated even when the acid acts.
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing an acid non-dissociable aliphatic cyclic group is preferable. As the cyclic group, many ones conventionally known as those used as a resin component of a resist composition for ArF excimer laser, KrF excimer laser (preferably ArF excimer laser) and the like can be used. ..
Particularly, at least one selected from a tricyclodecyl group, an adamantyl group, a tetracyclododecyl group, an isobornyl group, and a norbornyl group is preferable in terms of industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include structural units represented by general formulas (a4-1) to (a4-7) shown below.

［式中、Ｒ^αは前記と同じである。］

[In the formula, R ^α is the same as 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 proportion of the structural unit (a4) is preferably 1 to 40 mol% with respect to the total of all the structural units constituting the component (A1), It is more preferably 5 to 20 mol %.
By setting the proportion of the structural unit (a4) to the preferred lower limit or more, the effect of incorporating the structural unit (a4) can be sufficiently obtained, while setting the ratio to the preferred upper limit or less allows other structural units to be included. It becomes easy to balance with.

In the resist composition of the present embodiment, the component (A) contains the polymer compound (A1) having the structural unit (a0).
Examples of the component (A1) include a polymer compound having the structural unit (a0) and the structural unit (a2), and a polymer having the structural unit (a0), the structural unit (a2) and the structural unit (a3). Compounds.
As the component (A1), specifically, a copolymer having a repeating structure of a structural unit (a0), a structural unit (a2) and a structural unit (a3) is preferable.

The weight average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography (GPC)) of the component (A1) is not particularly limited and is preferably about 1000 to 500000, more preferably 2000 to 100000, and more preferably 3000. -50000 is more preferable.
When the Mw of the component (A1) is not more than the upper limit of the above preferred range, it has sufficient solubility in a resist solvent to be used as a resist, while on the other hand, it is not less than the above lower limit of the above preferred range. The dry etching resistance and the resist pattern sectional shape are improved.
The molecular weight dispersity (Mw/Mn) of the component (A1) is not particularly limited and is preferably about 1.0 to 4.0, more preferably 1.0 to 3.0, and 1.5 to 2.5. Particularly preferred. In addition, Mn shows a number average molecular weight.

As the component (A1), one type may be used alone, or two or more types may be used in combination.
The proportion of the component (A1) in the component (A) is preferably 25% by mass or more, more preferably 50% by mass or more, further preferably 75% by mass or more, and 100% by mass based on the total mass of the component (A). May be
When the ratio of the component (A1) is at least the lower limit value of the above preferred range, a resist pattern excellent in various lithographic properties such as high sensitivity and roughness improvement will be easily formed.

-Regarding Component (A2) In the resist composition of the present embodiment, as the component (A), a base component which does not correspond to the component (A1) and whose solubility in a developing solution is changed by the action of an acid (hereinafter referred to as “(A2) ) Component”)) may be used in combination.
The component (A2) is not particularly limited and may be arbitrarily selected from a large number of conventionally known base components for chemically amplified resist compositions.
As the component (A2), one type may be used alone, or two or more types may be used in combination.

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

<Other ingredients>
The resist composition of the present embodiment may further contain other components other than the component (A) in addition to the component (A) described above. Examples of the other component include the following component (B), component (D), component (E), component (F), and component (S).

<<Acid Generator Component (B)>>
The resist composition of the present embodiment may further contain an acid generator component (hereinafter referred to as “component (B)”) in addition to the component (A).
The component (B) is not particularly limited, and those which have been proposed as acid generators for chemically amplified resists can be used.
Examples of such an acid generator include onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators; diazomethane-based acid generators such as bisalkyl or bisarylsulfonyldiazomethanes and poly(bissulfonyl)diazomethanes. Acid generators: various types such as nitrobenzyl sulfonate-based acid generators, imino sulfonate-based acid generators, disulfone-based acid generators and the like can be mentioned. Above all, it is preferable to use an onium salt-based acid generator.

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

［式中、Ｒ^１０１、Ｒ^１０４〜Ｒ^１０８はそれぞれ独立に置換基を有していてもよい環式基、置換基を有していてもよい鎖状のアルキル基、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 formula, R< ¹⁰¹ >, R< ¹⁰⁴ >-R< ¹⁰⁸ > has a cyclic group which may have a substituent each independently, a chain-like alkyl group which may have a substituent, or a substituent. A chain-like alkenyl group which may be present. R ¹⁰⁴ and R ¹⁰⁵ may be bonded to each other to form a ring. R ¹⁰² is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. Y ¹⁰¹ is a single bond or a divalent linking group containing an oxygen atom. V ^{101 to} V ¹⁰³ are each independently a single bond, an alkylene group or a fluorinated alkylene group. L ^{101 to} L ¹⁰² are each independently a single bond or an oxygen atom. L ^{103 to} L ¹⁰⁵ are each independently a single bond, —CO— or —SO ₂ —. m is an integer of 1 or more, and M′ ^m+ is an m-valent onium cation. ]

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

Cyclic group which may have a substituent:
The cyclic group is preferably a cyclic hydrocarbon group, and the cyclic hydrocarbon group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity. Further, the aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

The aromatic hydrocarbon group for R ¹⁰¹ is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably has 5 to 30 carbon atoms, further preferably has 5 to 20 carbon atoms, particularly preferably has 6 to 15 carbon atoms, and most preferably has 6 to 10 carbon atoms. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic ring ^contained in the aromatic hydrocarbon group for R ¹⁰¹ are benzene, fluorene, naphthalene, anthracene, phenanthrene, biphenyl, or a part of carbon atoms constituting these aromatic rings is substituted with a hetero atom. An aromatic heterocycle etc. are mentioned. Examples of the hetero atom in the aromatic heterocycle include an oxygen atom, a sulfur atom and a nitrogen atom.
Specific examples of the aromatic hydrocarbon group for R ¹⁰¹ include a group in which one hydrogen atom is removed from the aromatic ring (aryl group: for example, phenyl group, naphthyl group, etc.), and one of the hydrogen atoms in the aromatic ring is alkylene. Examples thereof include groups substituted with groups (for example, arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group and 2-naphthylethyl group). The alkylene group (alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.

The cyclic aliphatic hydrocarbon group for R ¹⁰¹ includes an aliphatic hydrocarbon group containing a ring in the structure.
As the aliphatic hydrocarbon group containing a ring in this structure, an alicyclic hydrocarbon group (a group in which one hydrogen atom is removed from an aliphatic hydrocarbon ring), an alicyclic hydrocarbon group is linear or branched. Examples thereof include a group bonded to the end of a chain-like aliphatic hydrocarbon group and a group in which an alicyclic hydrocarbon group is present in the middle of a linear or branched aliphatic hydrocarbon group.
The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The alicyclic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic alicyclic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms from a monocycloalkane. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic alicyclic hydrocarbon group is preferably a group obtained by removing one or more hydrogen atoms from polycycloalkane, and the polycycloalkane preferably has 7 to 30 carbon atoms. Among them, the polycycloalkane includes a polycycloalkane having a polycyclic skeleton of a bridged ring system such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane; a condensed ring system such as a cyclic group having a steroid skeleton. A polycycloalkane having a polycyclic skeleton of is more preferable.

Among them, the cyclic aliphatic hydrocarbon group for R ¹⁰¹ is preferably a group obtained by removing one or more hydrogen atoms from monocycloalkane or polycycloalkane, and more preferably a group obtained by removing one hydrogen atom from polycycloalkane. Of these, an adamantyl group and a norbornyl group are particularly preferable, and an adamantyl group is the most preferable.

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

Further, the cyclic hydrocarbon group for R ¹⁰¹ may contain a hetero atom such as a heterocycle. Specifically, the lactone-containing cyclic groups respectively represented by the general formulas (a2-r-1) to (a2-r-7) and the general formulas (a5-r-1) to (a5-r-). -SO ₂ respectively represented by 4) - containing cyclic group, other above formula (r-hr-1) include heterocyclic groups respectively represented by ~ (r-hr-16) .

Examples of the substituent in the cyclic group of R ¹⁰¹ include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, a carbonyl group, a nitro group and the like.
As the alkyl group as a substituent, an alkyl group having 1 to 5 carbon atoms is preferable, and a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group are the most preferable.
The alkoxy group as a substituent is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, a tert-butoxy group, and a methoxy group. Most preferred is the group ethoxy.
Examples of the halogen atom as a substituent include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.
As the halogenated alkyl group as a substituent, a part or all of hydrogen atoms such as an alkyl group having 1 to 5 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group are the above. A group substituted with a halogen atom can be mentioned.
The carbonyl group as a substituent is a group that substitutes a methylene group (—CH ₂ —) forming a cyclic hydrocarbon group.

Chain-like alkyl group which may have a substituent:
The chain alkyl group for R ¹⁰¹ 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. Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, henicosyl group, docosyl group and the like.
The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, Examples thereof include a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group and a 4-methylpentyl group.

Chain-like alkenyl group which may have a substituent:
The chain alkenyl group for R ¹⁰¹ may be linear or branched and preferably has 2 to 10 carbon atoms, more preferably 2 to 5 and even more preferably 2 to 4 Is particularly preferable. Examples of the linear alkenyl group include a vinyl group, a propenyl group (allyl group) and a butynyl group. Examples of the branched alkenyl group include 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 straight chain alkenyl group, more preferably a vinyl group or a propenyl group, and particularly preferably a vinyl group.

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

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

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

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

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

The divalent saturated hydrocarbon group for V′ ¹⁰² is preferably an alkylene group having 1 to 30 carbon atoms, 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 in V′ ¹⁰¹ and V′ ¹⁰² may be a linear alkylene group or a branched alkylene group, and a linear alkylene group is preferable.
As the alkylene group for V′ ¹⁰¹ and V′ ¹⁰² , specifically, a methylene group [—CH ₂ —]; —CH(CH ₃ )—, —CH(CH ₂ CH ₃ )—, and —C(CH ₃ ). _{2 -, - C (CH 3} ) (CH 2 CH 3) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as ethylene group _{[-CH 2 CH 2 -];} - CH (CH 3) CH 2 -, - CH (CH 3) CH (CH 3) -, - C (CH 3) 2 CH 2 -, - CH (CH 2 CH - ₃₎ CH ₂ alkyl groups such as, trimethylene group (n- propylene _{group) [- CH 2 CH 2 CH} 2 -]; - CH (CH 3) CH 2 CH 2 -, - CH 2 CH (CH 3) tetramethylene group _{[-CH 2 CH 2 CH 2 CH} 2 -];; - CH 2 alkyltetramethylene groups such as _{- CH (CH 3) CH 2} CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH ₂ - and the like alkyl tetramethylene group; pentamethylene group _{[-CH 2 CH 2 CH 2 CH} 2 CH 2 -] , and the like.
Moreover, a part of the methylene groups in the alkylene group in V′ ¹⁰¹ or V′ ¹⁰² may be substituted with a divalent aliphatic cyclic group having 5 to 10 carbon atoms. The aliphatic cyclic group is a cyclic aliphatic hydrocarbon group for R ¹⁰¹ in the formula (b-1) (monocyclic alicyclic hydrocarbon group, polycyclic alicyclic hydrocarbon group). Is preferably a divalent group in which one more hydrogen atom is 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, and each is represented by the above formulas (y-al-1) to (y-al-5). A linking group is more preferred.

In formula (b-1), V ¹⁰¹ is a single bond, an alkylene group or a fluorinated alkylene group. The alkylene group and fluorinated alkylene group for V ¹⁰¹ preferably have 1 to 4 carbon atoms. ^Examples of the fluorinated alkylene group for V ¹⁰¹ include groups in which some or all of the hydrogen atoms of the alkylene group for V ¹⁰¹ 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 (b-1), R ¹⁰² is a fluorine atom or a fluorinated alkyl group having 1 to 5 carbon atoms. R ¹⁰² is preferably a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms, and more preferably a fluorine atom.

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

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

[In the formula, R" ¹⁰¹ is an aliphatic cyclic group which may have a substituent, a group represented by each of the formulas (r-hr-1) to (r-hr-6), or a substituent. R″ ¹⁰² is a chain alkyl group which may have a group; R″ ¹⁰² is an aliphatic cyclic group which may have a substituent, and the above general formulas (a2-r-1) to (a2- a lactone-containing cyclic group represented by each of r-7) or a -SO ₂ -containing cyclic group represented by each of the general formulas (a5-r-1) to (a5-r-4); R″ ¹⁰³ is an aromatic cyclic group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a chain alkenyl group which may have a substituent. V″ is each independently an integer of 0 to 3, q″ is independently an integer of 1 to 20, t″ is an integer of 1 to 3, and n″ is 0 or 1. .]

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

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

The chain alkyl group which may have a substituent in R″ ¹⁰¹ is preferably the group exemplified as the chain alkyl group in the above R ^101. The chain alkyl group which may have a substituent in R″ ¹⁰³ The chain alkenyl group which may be mentioned is preferably the group exemplified as the chain alkenyl group for R ¹⁰¹ .

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

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

{Cation part}
In the formulas (b-1), (b-2) and (b-3), m is an integer of 1 or more, M'm ⁺ is an m-valent onium cation, and a sulfonium cation and an iodonium cation are preferable. Of these, organic cations represented by the following general formulas (ca-1) to (ca-5) are particularly preferable.

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

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

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

［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。］

Wherein the R ^'201 independently, a hydrogen atom, have may have a substituent group cyclic group which may have a substituent chain alkyl group, or a substituent It may also be a chain alkenyl group. ]

The cyclic group that may have a substituent, the chain alkyl group that may have a substituent, or the chain alkenyl group that may have a substituent of R′ ²⁰¹ is as described above. In addition to the same as those of R ^{101 in} the formula (b-1), a cyclic alkyl group which may have a substituent or a chain alkyl group which may have a substituent may be mentioned above. The same as the acid dissociable group represented by the formula (a1-r-2) of

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

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

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

In the above formulas (ca-4) and (ca-5), Y ^201's each independently represent an arylene group, an alkylene group or an alkenylene group.
Examples of the arylene group for Y ²⁰¹ include a group obtained by removing one hydrogen atom from the aryl group exemplified as the aromatic hydrocarbon group for R ¹⁰¹ in the above formula (b-1).
Examples of the alkylene group and alkenylene group for Y ²⁰¹ include groups obtained by removing one hydrogen atom from the groups exemplified as the chain alkyl group and chain alkenyl group for R ¹⁰¹ in the above formula (b-1). ..

In the above formula (ca-4) and formula (ca-5), x is 1 or 2.
W ²⁰¹ is a (x+1)-valent, that is, a divalent or trivalent linking group.
As the divalent linking group for W ^{201, a} divalent hydrocarbon group which may have a substituent is preferable, and a divalent hydrocarbon group similar to Ya ²¹ in the above general formula (a2-1) has a substituent. Examples thereof include a divalent hydrocarbon group which may be added. The divalent linking group for W ²⁰¹ may be linear, branched, or cyclic, and is preferably cyclic. Of these, a group in which two carbonyl groups are combined at both ends of the arylene group is preferable. Examples of the arylene group include a phenylene group and a naphthylene group, and a phenylene group is particularly preferable.
^Examples of the trivalent linking group for W ²⁰¹ include a group obtained by removing one hydrogen atom from the divalent linking group for W ²⁰¹ , a group in which the divalent linking group is further bonded to the divalent linking group, and the like. Can be mentioned. As the trivalent linking group for W ²⁰¹ , a group in which two carbonyl groups are bonded to an arylene group is preferable.

Specific examples of the suitable cation represented by the formula (ca-1) include cations represented by the following formulas (ca-1-1) to (ca-1-67).

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

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

［式中、Ｒ”^２０１は水素原子又は置換基であって、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 the substituent which R ^{201 to} R ²⁰⁷ and R ^{210 to} R ²¹² may have. It is.]

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

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

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

Further, as the cation represented by the formula (ca-5), cations represented by the following general formulas (ca-5-1) to (ca-5-3) are also preferable.

Among the above, the cation moiety [(M′ ^m+ ) _1/m ] is preferably a cation represented by the general formula (ca-1), and in the formulas (ca-1-1) to (ca-1-67), More preferred are the cations represented respectively.

As the component (B), one type of acid generator described above may be used alone, or two or more types may be used in combination.
When the resist composition contains the component (B), the content of the component (B) is preferably 0.5 to 60 parts by mass, more preferably 1 to 50 parts by mass, relative to 100 parts by mass of the component (A). , 1 to 40 parts by mass is more preferable.
By setting the content of the component (B) within the above range, pattern formation is sufficiently performed. Moreover, when each component of the resist composition is dissolved in an organic solvent, a uniform solution is easily obtained, and the storage stability as the resist composition is improved, which is preferable.

<<Acid diffusion control agent component (D)>>
In addition to the component (A), or in addition to the components (A) and (B), the resist composition of the present embodiment further has an acid diffusion controller component (hereinafter referred to as “component (D)”). May be included. The component (D) acts as a quencher (acid diffusion control agent) that traps an acid generated by exposure in the resist composition.
The component (D) may be a photodegradable base (D1) (hereinafter referred to as “(D1) component”) that decomposes upon exposure and loses acid diffusion controllability, and is not included in the component (D1). It may be a nitrogen organic compound (D2) (hereinafter referred to as “component (D2)”).

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

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

{(D1-1) component}
..Anion moiety In formula (d1-1), Rd ¹ has a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a substituent. It may be a chain alkenyl group which may be the same as R ¹⁰¹ in the formula (b-1).
Among these, Rd ¹ may have an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a substituent. A chain alkyl group is preferred. Examples of the substituent 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 the above general formulas (a2-r-1) to (a2-r-). Examples thereof include a lactone-containing cyclic group represented by 7), an ether bond, an ester bond, or a combination thereof. When it contains an ether bond or an ester bond as a substituent, it may be via an alkylene group, and the substituent in this case is each represented by the above formulas (y-al-1) to (y-al-5). A linking group is preferred.
The aromatic hydrocarbon group is more preferably a phenyl group or a naphthyl group.
The aliphatic cyclic group is more preferably a group obtained by removing one or more hydrogen atoms from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane or tetracyclododecane.
The chain alkyl group preferably has 1 to 10 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, 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 Examples thereof include branched chain alkyl groups such as a group, a 2-ethylbutyl group, a 1-methylpentyl group, a 2-methylpentyl group, a 3-methylpentyl group and a 4-methylpentyl group.

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

Specific preferred examples of the anion moiety of the component (d1-1) are shown below.

··Cation part In formula (d1-1), M ^m+ is an m-valent organic cation.
Suitable examples of the organic cation of M ^m+ include those similar to the cations represented by the general formulas (ca-1) to (ca-5), and are represented by the general formula (ca-1). A cation is more preferable, and a cation represented by each of the formulas (ca-1-1) to (ca-1-67) is further preferable.
As the component (d1-1), one type may be used alone, or two or more types may be used in combination.

{(D1-2) component}
..Anion moiety In formula (d1-2), Rd ² has a cyclic group which may have a substituent, a chain alkyl group which may have a substituent, or a substituent. A chain alkenyl group which may be present, and examples thereof include the same ones as R ¹⁰¹ in the above formula (b-1).
However, a fluorine atom is not bonded to the carbon atom adjacent to the S atom in Rd ² (not fluorine-substituted). Thereby, the anion of the component (d1-2) becomes an appropriate weak acid anion, and the quenching ability as the component (D) is improved.
Rd ² is preferably a chain-like alkyl group which may have a substituent or an aliphatic cyclic group which may have a substituent. The chain alkyl group preferably has 1 to 10 carbon atoms, and more preferably 3 to 10 carbon atoms. As the aliphatic cyclic group, a group obtained by removing one or more hydrogen atoms from adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane or the like (which may have a substituent); one from camphor or the like It is more preferably a group excluding the above hydrogen atoms.
The hydrocarbon group of Rd ² may have a substituent, and as the substituent, the hydrocarbon group (aromatic hydrocarbon group, aliphatic cyclic group, Rd ¹ in Rd ¹ of the above formula (d1-1), Examples thereof include the same substituents that the chain alkyl group) may have.

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

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

{(D1-3) component}
During ... anion formula (d1-3), Rd ³ is have may have a substituent group cyclic group, substituent having optionally also good chain alkyl group, or a substituent Which may be a chain alkenyl group, and examples thereof include those similar to R ¹⁰¹ in the above formula (b-1), and a cyclic group containing a fluorine atom, a chain alkyl group, or a chain alkenyl group Is preferred. Among them, a fluorinated alkyl group is preferable, and a group similar to the fluorinated alkyl group for Rd ¹ is more preferable.

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

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

Examples of the cyclic group for Rd ⁴ include the same as those for R ¹⁰¹ in the above formula (b-1). An alicyclic group excluding one or more hydrogen atoms, or an aromatic group such as a phenyl group or a naphthyl group is preferable. When Rd ⁴ is an alicyclic group, the resist composition is well dissolved in an organic solvent, and thus the lithographic properties are good. Further, when Rd ⁴ is an aromatic group, the resist composition has excellent light absorption efficiency in lithography using EUV or the like as an exposure light source, and sensitivity and lithographic properties are good.

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

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

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

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

Method for producing component (D1):
The method for producing the above-mentioned component (d1-1) and component (d1-2) is not particularly limited and can be produced by a known method.
The method for producing the component (d1-3) is not particularly limited, and for example, it is produced in the same manner as the method described in US2012-0149916.

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

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

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

An aromatic amine may be used as the component (D2).
Examples of aromatic amines include 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxycarbonylpyrrolidine and the like.

As the component (D2), one type may be used alone, or two or more types may be used in combination.
When the resist composition contains the component (D2), the component (D2) is usually used in the range of 0.01 to 5 parts by mass with respect to 100 parts by mass of the component (A). By setting the content in the above range, the resist pattern shape, the stability over time of leaving and the like are improved.

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

≪Fluorine additive component (F)≫
The resist composition of the present embodiment may contain a fluorine additive component (hereinafter referred to as “(F) component”) in order to impart water repellency to the resist film.
Examples of the component (F) are described in JP2010-002870A, JP2010-032994A, JP2010-277043A, JP2011-13569A, and JP2011-128226A. The fluorine-containing polymer compound can be used.
More specifically, the component (F) includes a polymer having a structural unit (f1) represented by the following formula (f1-1). As the polymer, a polymer (homopolymer) consisting only of a structural unit (f1) represented by the following formula (f1-1); a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid. And a structural unit (f1); a copolymer of the structural unit (f1), a structural unit derived from acrylic acid or methacrylic acid, and the structural unit (a1). Is preferred. Here, as the structural unit (a1) 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)acrylate are preferred.

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

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

In formula (f1-1), R bonded to the carbon atom at the α-position is the same as above. R is preferably a hydrogen atom or a methyl group.
In formula (f1-1), examples of the halogen atom of Rf ¹⁰² and Rf ¹⁰³ include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom is particularly preferable. Examples of the alkyl group having 1 to 5 carbon atoms of Rf ¹⁰² and Rf ¹⁰³ are the same as those of the alkyl group having 1 to 5 carbon atoms of 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 of the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. Be done. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is particularly preferable. Among them, Rf ¹⁰² and Rf ¹⁰³ are preferably a hydrogen atom, a fluorine atom or an alkyl group having 1 to 5 carbon atoms, and a hydrogen atom, a fluorine atom, a methyl group or an ethyl group is preferable.
In the formula (f1-1), nf ¹ is an integer of ¹ to 5, preferably an integer of 1 to 3, and more preferably 1 or 2.

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

The weight average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography) of the component (F) is preferably from 1,000 to 50,000, more preferably from 5,000 to 40,000, and most preferably from 10,000 to 30,000. When it is at most the upper limit of this range, it has sufficient solubility in a resist solvent for use as a resist, and when it is at least the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good. .
The dispersity (Mw/Mn) of the component (F) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5.

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

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

≪ Organic solvent component (S)≫
The resist composition of this embodiment can be produced by dissolving the resist material in an organic solvent component (hereinafter sometimes referred to as “(S) component”).
As the component (S), any component capable of dissolving each component used to form a uniform solution may be used, and any one of the conventionally known solvents for chemically amplified resist compositions may be appropriately used. It can be selected and used.
For example, 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, dipropylene glycol and the like. Polyhydric alcohols; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, or dipropylene glycol monoacetate, monomethyl ethers of the polyhydric alcohols or compounds having an ester bond, monoethyl Derivatives of polyhydric alcohols such as monoalkyl ethers such as ether, monopropyl ether, monobutyl ether or compounds having an ether bond such as 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, methyl methoxypropionate, ethoxy. Esters such as ethyl propionate; such as anisole, ethylbenzyl ether, cresylmethyl ether, diphenyl ether, dibenzyl ether, phenetol, butylphenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. Examples thereof include aromatic organic solvents and dimethyl sulfoxide (DMSO).
The component (S) may be used alone or as a mixed solvent of two or more kinds.
Among them, PGMEA, PGME, γ-butyrolactone, EL and cyclohexanone are preferable.
A mixed solvent obtained by mixing PGMEA and a polar solvent is also preferable. The compounding ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, and is preferably 1:9 to 9:1, more preferably 2:8 to 8:2. It is preferably within the range.
More specifically, when EL or cyclohexanone is blended as the polar solvent, the mass ratio of PGMEA:EL or cyclohexanone is preferably 1:9 to 9:1, more preferably 2:8 to 8:2. . When PGME is blended as the polar solvent, the mass ratio of PGMEA:PGME is preferably 1:9 to 9:1, more preferably 2:8 to 8:2, and further preferably 3:7 to 7:. It is 3. Further, a mixed solvent of PGMEA, PGME and cyclohexanone is also preferable.
In addition, as the component (S), a mixed solvent of γ-butyrolactone with at least one selected from PGMEA and EL is also preferable. In this case, as the mixing ratio, the mass ratio of the former and the latter is preferably 70:30 to 95:5.
The amount of the component (S) used is not particularly limited, and is appropriately set according to the coating film thickness at a concentration such that it can be coated on a substrate or the like. Generally, the component (S) is used such that the solid content concentration of the resist composition is in the range of 1 to 20% by mass, preferably 2 to 15% by mass.

According to the resist composition of the present embodiment described above, in the formation of the resist pattern, it is possible to obtain the effects that the sensitivity can be further enhanced and the shape of the resist pattern can be further improved.
In the resist composition of the embodiment, a polymer compound (A1) having a structural unit (a0) represented by general formula (a0-1) is used as a base material component (A). This structural unit (a0) has an acid dissociable group represented by general formula (a0-r1-1) at the side chain terminal. Such acid-dissociable group, a quaternary carbon atom (Ya ^0), and a polar group, include.
When the acid dissociable group contains a quaternary carbon atom (Ya ⁰ ), when the resist pattern is formed, as compared with the case where the acid dissociable group has a tertiary carbon atom, The acid dissociation property by exposure is easily improved. Therefore, the reactivity is enhanced and the sensitivity is enhanced. In addition, high dissolution contrast can be obtained by development.
Further, since the acid dissociable group contains a polar group, the solubility in a developing solution containing an organic solvent can be suppressed to be low. Therefore, during solvent development, in the exposed portion of the resist film, when the acid dissociable group remains without being decomposed or remains in the resist film as a decomposed product, the organic developer in the exposed portion of the resist film Since it becomes difficult for the dissolution rate to increase, it becomes possible to suppress the film loss of the pattern portion. In addition, it becomes possible to prevent partial dissolution of the pattern boundary portion. Furthermore, since the acid dissociable group contains a polar group, the affinity for the alkali developing solution can be improved. For this reason, at the time of alkali development, the solubility in the alkali developing solution becomes high, so that the development proceeds more uniformly and smoothly.
Due to the above-described action, in forming a resist pattern using the resist composition of the embodiment, lithography properties such as in-plane uniformity (CDU) of pattern dimensions and circularity (circularity) are further improved, which is favorable. A resist pattern of various shapes can be formed.

(Method of forming resist pattern)
The resist pattern forming method of the present embodiment, the step of forming a resist film using the above-mentioned (resist composition) on the support, exposing the resist film, and developing the resist film after the exposure And a resist pattern is formed.
The resist pattern forming method of this embodiment can be performed as follows, for example.

First, the resist composition of the present embodiment described above is applied on a support by a spinner or the like, and a baking (post-apply bake (PAB)) treatment is performed for 40 to 120 seconds under a temperature condition of 80 to 150° C., for example. Preferably for 60 to 90 seconds to form a resist film.
Next, using an exposure device such as an ArF exposure device, an electron beam exposure device, and an EUV exposure device, the resist film is exposed through a mask (mask pattern) on which a predetermined pattern is formed or a mask pattern is formed. After performing selective exposure such as drawing by direct irradiation with an electron beam without intervention, baking (post exposure bake (PEB)) treatment is performed for 40 to 120 seconds at a temperature condition of 80 to 150° C., preferably 60 to Apply for 90 seconds.
Next, the resist film is developed. The development treatment is performed using an alkali developing solution in the case of an alkali developing process, and using a developing solution containing an organic solvent (organic developing solution) in the case of a solvent developing process.
After the development processing, rinsing processing is preferably performed. The rinse treatment is preferably a water rinse using pure water in the case of an alkali development process, and preferably a rinse liquid containing an organic solvent in the case of a solvent development process.
In the case of the solvent developing process, after the developing process or the rinsing process, a process of removing the developing solution or the rinsing solution adhering to the pattern with a supercritical fluid may be performed.
After development or rinsing, drying is performed. In some cases, a bake treatment (post bake) may be performed after the above development treatment.
In this way, the resist pattern can be formed.

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

The wavelength used for exposure is not particularly limited, and includes ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. It can be done using radiation. The resist composition is highly useful for KrF excimer laser, ArF excimer laser, EB or EUV, and is particularly useful for ArF excimer laser, EB or EUV.

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

Examples of the alkaline developing solution used for the developing treatment in the alkaline developing process include 0.1 to 10% by mass tetramethylammonium hydroxide (TMAH) aqueous solution.
The organic solvent contained in the organic developing solution used for the developing treatment in the solvent developing process may be any one capable of dissolving the component (A) (component (A) before exposure), and among known organic solvents. It can be selected appropriately. Specific examples thereof include polar solvents such as a ketone solvent, an ester solvent, an alcohol solvent, a nitrile solvent, an amide solvent, an ether solvent, and a hydrocarbon solvent.
The ketone solvent is an organic solvent containing C—C(═O)—C in the structure. The ester solvent is an organic solvent containing C—C(═O)—O—C in the structure. The alcohol solvent is an organic solvent containing an alcoholic hydroxyl group in its structure. "Alcoholic hydroxyl group" means a hydroxyl group bonded to a carbon atom of an aliphatic hydrocarbon group. A nitrile solvent is an organic solvent containing a nitrile group in its structure. The amide solvent is an organic solvent containing an amide group in its structure. The ether solvent is an organic solvent containing C—O—C in the structure.
Among the organic solvents, there are also organic solvents containing a plurality of functional groups that characterize the above-mentioned respective solvents in the structure, but in that case, the organic solvent corresponds to any solvent species containing a functional group. I shall. For example, diethylene glycol monomethyl ether corresponds to both alcohol solvents and ether solvents in the above classification.
The hydrocarbon solvent is a hydrocarbon solvent which may be halogenated and does not have a substituent other than a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.
Among the above, the organic solvent contained in the organic developer is preferably a polar solvent, and is preferably a ketone solvent, an ester solvent, a nitrile solvent, or the like.

Examples of the ketone solvent include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutylketone, cyclohexanone, methylcyclohexanone, phenylacetone, methylethylketone. , Methyl isobutyl ketone, acetylacetone, acetonylacetone, ionone, diacetonyl alcohol, acetylcarbinol, acetophenone, methylnaphthylketone, isophorone, propylene carbonate, γ-butyrolactone, methylamylketone (2-heptanone) and the like. Among these, methyl amyl ketone (2-heptanone) is preferable as the ketone solvent.

Examples of the ester solvent 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 monoester. 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. Of these, butyl acetate is preferable as the ester solvent.

Examples of the nitrile solvent include acetonitrile, propionitolyl, valeronitrile, butyronitol and the like.

If desired, known additives can be added to the organic developer. Examples of the additive include a surfactant. Although the surfactant is not particularly limited, for example, an ionic or nonionic fluorine-based and/or silicon-based surfactant or the like 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 the surfactant is blended, the blending amount thereof is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and 0.01 to 0. 5 mass% is more preferable.

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

As the organic solvent contained in the rinse liquid used in the rinse treatment after the development treatment in the solvent development process, for example, among the organic solvents used as the organic solvent used in the organic developer, one which does not easily dissolve the resist pattern is appropriately selected. Can be used. Usually, at least one solvent selected from a hydrocarbon solvent, a ketone solvent, an ester solvent, an alcohol solvent, an amide solvent and an ether solvent is used. Among these, at least one selected from a hydrocarbon solvent, a ketone solvent, an ester solvent, an alcohol solvent and an amide solvent is preferable, and at least one selected from an alcohol solvent and an ester solvent. More preferably, alcohol solvents are particularly preferable.
The alcohol solvent used for 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 preferable, and 1-hexanol and 2-hexanol are more preferable.
These organic solvents may be used alone or in combination of two or more. Further, it may be used by mixing with an organic solvent or water other than the above. However, considering development characteristics, the content of water in the rinse liquid is preferably 30% by mass or less, more preferably 10% by mass or less, further preferably 5% by mass or less, and more preferably 3% by mass, based on the total amount of the rinse liquid. The following are particularly preferred.
Known additives may be added to the rinse liquid, if necessary. Examples of the additive include a surfactant. As the surfactant, the same ones as mentioned above can be mentioned, and a nonionic surfactant is preferable, and a nonionic fluorine-based surfactant or a nonionic silicon-based surfactant is more preferable.
When compounding a surfactant, the compounding quantity is usually 0.001 to 5 mass%, preferably 0.005 to 2 mass%, and 0.01 to 0.5 mass% with respect to the total amount of the rinse liquid. % Is more preferable.

The rinse treatment (washing treatment) using the rinse liquid can be carried out by a known rinse method. Examples of the rinsing method include a method of continuously applying a rinsing liquid onto a support rotating at a constant speed (rotational coating method), a method of immersing the support in the rinsing liquid for a certain time (dip method), Examples thereof include a method of spraying a rinse liquid on the surface of the support (spray method).

According to the resist pattern forming method of the present embodiment described above, since the above-mentioned (resist composition) is used, it is possible to improve the sensitivity and the lithography characteristics and form a resist pattern having a better shape. ..

(Polymer compound)
The polymer compound of the present embodiment has a structural unit (a0) represented by general formula (a0-1) shown below.

［式中、Ｒは、水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基である。Ｖａ^０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_ａ０は、０〜２の整数である。Ｒａ^００は、一般式（ａ０−ｒ１−１）で表される酸解離性基である。Ｒａ^０１は、置換基を有していてもよい炭化水素基である。Ｒａ^０２は、置換基を有していてもよい炭化水素基である。Ｒａ^０１とＲａ^０２とは相互に結合して、環構造を形成してもよい。Ｙａ^０は、第４級炭素原子である。Ｒａ^０３１、Ｒａ^０３２及びＲａ^０３３は、それぞれ独立に、置換基を有していてもよい炭化水素基である。但し、Ｒａ^０３１、Ｒａ^０３２及びＲａ^０３３のうちの１つ以上は、少なくとも極性基を有する炭化水素基である。］

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Va ⁰ is a divalent hydrocarbon group which may have an ether bond. _na0 is an integer of 0-2. Ra ⁰⁰ is an acid dissociable group represented by the general formula (a0-r1-1). Ra ⁰¹ is a hydrocarbon group which may have a substituent. Ra ⁰² is a hydrocarbon group which may have a substituent. Ra ⁰¹ and Ra ⁰² may be bonded to each other to form a ring structure. Ya ⁰ is a quaternary carbon atom. Ra ⁰³¹ , Ra ⁰³² and Ra ⁰³³ are each independently a hydrocarbon group which may have a substituent. However, one or more of Ra ⁰³¹ , Ra ^032, and Ra ⁰³³ is a hydrocarbon group having at least a polar group. ]

In the polymer compound of the embodiment, the ratio of the structural unit (a0) is, for example, 10 to 70 with respect to the total of all structural units constituting the polymer compound when applied to a base resin for a resist composition. Mol% is preferable, and 20 to 50 mol% is particularly preferable.

The polymer compound of this embodiment is the same as the component (A1) (polymer compound having the structural unit (a0)) in the description of the (resist composition) described above, and is present in addition to the structural unit (a0). The types of constituent units that may be used, the content ratio of each constituent unit in the component (A1), and the like are the same as above.

In the polymer compound of such an embodiment, a monomer that induces the structural unit (a0) and, if necessary, a monomer that induces a structural unit other than the structural unit (a0) are dissolved in a polymerization solvent. It can be produced by adding a radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dimethyl azobisisobutyrate (for example, V-601) and polymerizing.
Incidentally, during the polymerization, for _example, by using a combination of chain transfer agent such as _{HS-CH 2 -CH 2 -CH 2} -C (CF 3) 2 -OH, -C terminated _(CF 3) _{A 2-} OH group may be introduced. As described above, the copolymer having a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom is introduced, reduction of development defects and LER (line edge roughness: uneven unevenness of line side wall). Is effective in reducing

The monomer for deriving the structural unit (a0) can be produced, for example, by the method referring to the synthesis described in paragraphs 0087 and 0090 of WO 2013/042694.

The polymer compound of the present embodiment is a novel substance that is useful as a base resin for a resist composition, and has a film-forming base material component, and in addition, its solubility in a developer is changed by the action of an acid. The resin component ((A1) component) can be suitably added to the resist composition.

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

<Production Example of Monomer (a01)>
With reference to the synthesis examples described in paragraphs 0087 and 0090 of WO 2013/042694, the synthesis is performed using methyl 2,2-dimethyl-3-methoxypropionate or the like as a raw material to obtain the target monomer (a01). That is, 1-(2′-methoxy-1′,1′-dimethylethyl)cyclopentan-1-yl methacrylate having the following NMR characteristics was obtained.

The obtained monomer (a01) was subjected to NMR measurement, and its structure was identified by the following results.
¹ H-NMR (CDCl ₃ ) δ (ppm)=6.00 (m, 1H), 5.47 (m, 1H), 3.10 (s, 3H), 3.08 (s, 2H), 2 .20-2.12 (m, 2H), 2.05-1.95 (m, 4H), 1.93 (t, 3H), 1.60-1.50 (m, 2H), 1.02. (S, 6H).

<Production example of base material component (polymer compound)>
The polymer compound used in this example was produced as follows (see Patent Document 2: JP-A-2015-169843).

26.40 g of methyl ethyl ketone (MEK) was put into a separable flask connected with a thermometer, a reflux tube, and a nitrogen introducing tube, and heated to 80°C. Here, 3.5 g of the monomer (a21), 1.1 g of the monomer (a22), 4.59 g of the monomer (a01), 0.9 g of the monomer (a31), and 0.79 g of the polymerization initiator. Of dimethyl azobisisobutyrate (V-601) of Example 1 was dissolved in 74.67 g of MEK, and the solution was added dropwise over 4 hours under a nitrogen atmosphere. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature. The obtained reaction polymerization liquid is dropped into a large amount of n-heptane to precipitate a polymer, and the precipitated white powder is filtered and dried to obtain the target polymer compound (A1-1)6. 0.7 g was obtained.

Regarding the obtained polymer compound (A1-1), the weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 7,900, and the molecular weight dispersity (Mw/Mn) was 1.61. .. ^The copolymerization composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by ¹³ C-NMR was 1/m/n/o=3/1/5/1.

<Preparation of resist composition>
(Example 1, Comparative Examples 1 to 4)
The components shown in Table 1 were mixed and dissolved to prepare the resist composition of each example (solid content concentration 3.0% by mass).

In Table 1, each abbreviation has the following meanings. The numerical value in [] is a compounding amount (part by mass).
(A1)-1: The polymer compound (A1-1).

(A2)-1: A polymer compound represented by the following chemical formula (A2-1). The weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 7,000, and the molecular weight dispersity (Mw/Mn) was 1.50. ^The copolymerization composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by ¹³ C-NMR was 1/m/n/o=3/1/5/1.

(A2)-2: A polymer compound represented by the following chemical formula (A2-2). The weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement is 7,500, and the molecular weight dispersity (Mw/Mn) is 1.48. ^The copolymerization composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by ¹³ C-NMR was 1/m/n/o=3/1/5/1.

(A2)-3: A polymer compound represented by the following chemical formula (A2-3). The weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 5700, and the molecular weight dispersity (Mw/Mn) was 1.49. ^The copolymerization composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by ¹³ C-NMR was 1/m/n/o=3/1/5/1.

(A2)-4: A polymer compound represented by the following chemical formula (A2-4). The standard polystyrene equivalent weight average molecular weight (Mw) determined by GPC measurement was 6,500, and the molecular weight dispersity (Mw/Mn) was 1.52. ^The copolymerization composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by ¹³ C-NMR was 1/m/n/o=3/1/5/1.

(B)-1: A compound (acid generator) represented by the following chemical formula (B-1).
(D)-1: a compound (acid diffusion controller) represented by the following chemical formula (D-1).

(F)-1: A fluorine-containing polymer compound represented by the following chemical formula (F-1). The weight average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement was 15,500, and the molecular weight dispersity (Mw/Mn) was 1.67. ^The copolymerization composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by ¹³ C-NMR was 1/m=5/5.
(S)-1: Mixed solvent of propylene glycol monomethyl ether acetate/propylene glycol monomethyl ether/cyclohexanone=45/30/25 (mass ratio).

<Formation of resist pattern>
A resist composition of each example was applied on a 8-inch silicon substrate treated with hexamethyldisilazane (HMDS) by using a spinner, and prebaked (PAB) at a temperature of 110° C. for 60 seconds on a hot plate. By performing the treatment, it was dried to form a resist film having a film thickness of 90 nm.
Next, an ArF excimer laser (193 nm) was applied to the resist film of the target (hole diameter 67 nm/pitch 130 nm) using an ArF exposure device S610C (NA1.20; Annual, 0.90/0.70). Irradiation was performed selectively through a mask pattern.
After that, a post-exposure heating (PEB) treatment was performed at 80° C. for 60 seconds.
Then, at 23° C., solvent development was performed for 30 seconds using butyl acetate, and then rinse treatment was performed.
As a result, a contact hole (CH) pattern having a hole diameter of 73 nm/pitch of 130 nm was formed.

[Evaluation of optimum exposure amount (EOP)]
The optimum exposure dose EOP (mJ/cm ² ) for forming the CH pattern of the target size by the above-mentioned <Formation of resist pattern> was determined. This is shown in Table 2 as "EOP (mJ/cm ² )".

[Evaluation of in-plane uniformity of pattern dimensions (CDU)]
With respect to the CH pattern formed by the above <Formation of resist pattern>, the CH pattern is emptied by a measuring SEM (scanning electron microscope, accelerating voltage 300V, trade name: S-9380, manufactured by Hitachi High-Technologies Corporation). And the hole diameter (nm) of 100 holes in the CH pattern was measured. A triple value (3σ) of the standard deviation (σ) calculated from the measurement result was obtained. This is shown in Table 2 as "CDU (nm)".
The smaller the value of 3σ obtained in this way, the higher the uniformity (CD) of the holes formed in the resist film.

[Evaluation of Circularity]
The 25 holes in the CH pattern formed by the above <Formation of resist pattern> were measured by a measuring SEM (scanning electron microscope, accelerating voltage 300V, trade name: S-9380, manufactured by Hitachi High-Technologies Corporation). Observing from the sky, the distance from the center of each hole to the outer edge was measured in 24 directions. A triple value (3σ) of the standard deviation (σ) calculated from the measurement result was obtained. This is shown in Table 2 as "Circuality (nm)".
The smaller the value of 3σ obtained in this way, the higher the roundness of the hole.

From the results shown in Table 2, according to the resist composition of Example 1 to which the present invention is applied, higher sensitivity and improvement of lithographic characteristics can be achieved and better than the resist compositions of Comparative Examples 1 to 4. It can be confirmed that a resist pattern having a shape can be formed.

Claims (5)

A resist composition which generates an acid upon exposure and whose solubility in a developing solution is changed by the action of the acid,
Contains a base material component (A) whose solubility in a developer is changed by the action of an acid,
The resist composition, wherein the base component (A) contains a polymer compound (A1) having a structural unit (a0) represented by general formula (a0-1) shown below.

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Va ⁰ is a divalent hydrocarbon group which may have an ether bond. _na0 is an integer of 0-2. Ra ⁰⁰ is an acid dissociable group represented by the general formula (a0-r1-1). Ra ⁰¹ is a hydrocarbon group which may have a substituent. Ra ⁰² is a hydrocarbon group which may have a substituent. Ra ⁰¹ and Ra ⁰² may be bonded to each other to form a ring structure. Ya ⁰ is a quaternary carbon atom. Ra ⁰³¹ , Ra ⁰³² and Ra ⁰³³ are each independently a hydrocarbon group which may have a substituent. However, one or more of Ra ⁰³¹ , Ra ⁰³² and Ra ⁰³³ is a hydrocarbon group having a polar group represented by any of the following formulas (a0-p1-1) to (a0-p1-9). Is. In formula (a0-r1-1), * is a bond that bonds to the oxy group (-O-) of the carbonyloxy group [-C(=O)-O-] in formula (a0-1). Represents Wherein (a0-p1-1) ~ (a0 -p1-9), * indicates that a bond that binds to a quaternary carbon atom (Ya ^0). ]

The resist composition according to claim 1, wherein the ratio of the structural unit (a0) is 10 to 70 mol% with respect to the total of all the structural units constituting the polymer compound (A1). A step of forming a resist film using the resist composition according to claim 1 or 2 on a support, a step of exposing the resist film, and a step of developing the exposed resist film to form a resist pattern. A method of forming a resist pattern, comprising the steps of: A polymer compound having a structural unit (a0) represented by general formula (a0-1) shown below.

[In formula, R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group. Va ⁰ is a divalent hydrocarbon group which may have an ether bond. _na0 is an integer of 0-2. Ra ⁰⁰ is an acid dissociable group represented by the general formula (a0-r1-1). Ra ⁰¹ is a hydrocarbon group which may have a substituent. Ra ⁰² is a hydrocarbon group which may have a substituent. Ra ⁰¹ and Ra ⁰² may be bonded to each other to form a ring structure. Ya ⁰ is a quaternary carbon atom. Ra ⁰³¹ , Ra ⁰³² and Ra ⁰³³ are each independently a hydrocarbon group which may have a substituent. However, one or more of Ra ⁰³¹ , Ra ^032, and Ra ⁰³³ is a hydrocarbon group having a polar group represented by any of the following formulas (a0-p1-1) to (a0-p1-9). Is. In formula (a0-r1-1), * is a bond that bonds to the oxy group (-O-) of the carbonyloxy group [-C(=O)-O-] in formula (a0-1). Represents. Wherein (a0-p1-1) ~ (a0 -p1-9), * indicates that a bond that binds to a quaternary carbon atom (Ya ^0). ]

The polymer compound according to claim 4, wherein the ratio of the structural unit (a0) is 20 to 50 mol% based on the total of all the structural units constituting the polymer compound.