JP5462681B2 - Positive resist composition, resist pattern forming method, polymer compound, compound - Google Patents

Description

  The present invention relates to a novel polymer compound that can be used as a base component of a positive resist composition, a compound useful as a monomer of the polymer compound, a positive resist composition containing the polymer compound, and the positive type The present invention relates to a resist pattern forming method using a resist composition.

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, and the resist film is selectively exposed to light such as light or an electron beam through a mask on which a predetermined pattern is formed. And a development process is performed to form a resist pattern having a predetermined shape on the resist film.
A resist material in which the exposed portion changes to a property that dissolves in the developer is referred to as a positive type, and a resist material that changes to a property in which the exposed portion does not dissolve in the developer is referred to as a negative type.
In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, pattern miniaturization has been rapidly progressing due to advances in lithography technology.
As a technique for miniaturization, the exposure light source is generally shortened in wavelength (increased energy). Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but at present, mass production of semiconductor elements using a KrF excimer laser or an ArF excimer laser has started. Further, studies have been made on EB (electron beam), EUV (extreme ultraviolet), X-rays, and the like having shorter wavelengths (higher energy) than these excimer lasers.

Along with the shortening of the wavelength of the exposure light source, the resist material is required to be improved in lithography characteristics such as sensitivity to the exposure light source and resolution capable of reproducing a pattern with a fine dimension.
As a resist material that satisfies such requirements, a chemically amplified resist containing a base material component whose solubility in an alkaline developer is changed by the action of an acid and an acid generator component that generates an acid upon exposure is used. Yes.
For example, as a positive chemically amplified resist composition, a composition containing a resin component (base resin) whose solubility in an alkaline developer is increased by the action of an acid and an acid generator component is generally used. Yes. When a resist film formed using such a resist composition is subjected to selective exposure at the time of resist pattern formation, an acid is generated from the acid generator in the exposed portion, and the acid acts on the alkaline developer of the resin component. Solubility increases and the exposed part becomes soluble in an alkaline developer.

Currently, as a resist base resin used in ArF excimer laser lithography and the like, a resin having a structural unit derived from a (meth) acrylate ester in the main chain because it is excellent in transparency near 193 nm ( Acrylic resin) is used. (For example, refer to Patent Document 1).
Here, “(meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position. “(Meth) acrylate” means 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. “(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.

JP 2003-241385 A JP 2000-235264 A

J. et al. Vac. Sci. Technol. B24 (2006) 3055 Proc. of SPIE Vol. 7,271 721724-1 (2009)

As further advances in lithography technology and miniaturization of resist patterns continue in the future, there is a further demand for resist materials to form resist patterns with higher resolution while maintaining good lithography characteristics. It is growing.
Lithography by EB or EUV has a reaction mechanism different from that of normal optical lithography (Non-Patent Document 1), and is aimed at forming a fine pattern of several tens of nm. Thus, there is a demand for resist compositions that are more sensitive to the exposure light source as the resist pattern dimensions become smaller.
In addition, there is a problem that the outgas generated by the progress of the deprotection reaction of the protecting group contained in the resin contaminates the exposure apparatus, and there is a need for a solution.
Further, as the pattern becomes finer, the formed resist film is also made thinner. For example, in the case of EB and EUV applications, a film thickness of 60 nm or less has been studied (Non-Patent Document 2). Under such circumstances, it is important to suppress the reduction of the resist film when the resist film is exposed and developed. For example, in the case of a positive type, an unexposed portion remains without being removed during development, but due to film reduction, unevenness is generated on the upper surface of the resist pattern, and resolution and pattern shape may be deteriorated.
In addition, the resist pattern cannot be sufficiently high, and may not function sufficiently as an etching mask when forming a semiconductor element.
For example, the protecting group in the polymer of C-32 described in Patent Document 2 (paragraph 0066) cannot sufficiently satisfy the above performance.
The present invention has been made in view of the above circumstances, and has a positive lithographic property and a reduced resist film thickness at the time of forming a resist pattern, and a resist using the positive resist composition It is an object of the present invention to provide a pattern forming method, a polymer compound useful as a base component of a positive resist composition, and a compound useful as a monomer of the polymer compound.

In order to solve the above problems, the present invention employs the following configuration.
That is, the first aspect of the present invention is a positive type containing a base component (A) whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator component (B) that generates an acid upon exposure. A positive resist comprising a resist composition, wherein the base material component (A) contains a polymer compound (A1) having a structural unit (a0) represented by the following general formula (a0) It is a composition.

［式中、Ｒは、水素原子、炭素数１〜５のアルキル基、または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^１、Ｒ^２はそれぞれ独立に、メチル基、エチル基またはイソプロピル基であり、Ｒ^３、Ｒ^４はそれぞれ独立に、ハロゲン原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、ｐは０〜３の整数であり、ｑは０〜４の整数である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and R ¹ and R ² are each independently a methyl group, an ethyl group, or isopropyl. R ³ and R ⁴ are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, p is an integer of 0 to 3, q Is an integer from 0 to 4. ]

  According to a second aspect of the present invention, there is provided a step of forming a resist film on a support using the positive resist composition of the first aspect, a step of exposing the resist film, and an alkali development of the resist film. And a resist pattern forming method including a step of forming a resist pattern.

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

［式中、Ｒは、水素原子、炭素数１〜５のアルキル基、または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^１、Ｒ^２はそれぞれ独立に、メチル基、エチル基またはイソプロピル基であり、Ｒ^３、Ｒ^４はそれぞれ独立に、ハロゲン原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、ｐは０〜３の整数であり、ｑは０〜４の整数である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and R ¹ and R ² are each independently a methyl group, an ethyl group, or isopropyl. R ³ and R ⁴ are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, p is an integer of 0 to 3, q Is an integer from 0 to 4. ]

  A fourth aspect of the present invention is a compound represented by the following general formula (M0).

［式中、Ｒは、水素原子、炭素数１〜５のアルキル基、または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^１、Ｒ^２はそれぞれ独立に、メチル基、エチル基またはイソプロピル基であり、Ｒ^３、Ｒ^４はそれぞれ独立に、ハロゲン原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、ｐは０〜３の整数であり、ｑは０〜４の整数である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and R ¹ and R ² are each independently a methyl group, an ethyl group, or isopropyl. R ³ and R ⁴ are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, p is an integer of 0 to 3, q Is an integer from 0 to 4. ]

In the present specification and claims, “aliphatic” is a relative concept with respect to aromatics, and is defined to mean groups, compounds, etc. that do not have aromaticity.
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups.
Unless otherwise specified, the “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups. The same applies to the alkyl group in the alkoxy group.
The “halogenated alkyl group” is a group in which part or all of the hydrogen atoms of the 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.
“Fluorinated alkyl group” or “fluorinated alkylene group” refers to a group in which part or all of the hydrogen atoms of an alkyl group or alkylene group are substituted with fluorine atoms.
“Structural unit” means a monomer unit (monomer unit) constituting a polymer compound (resin, polymer, copolymer).
“A structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid esters” include those in which a hydrogen atom is bonded to the carbon atom at the α-position, and those in which a substituent (atom or group other than a hydrogen atom) is bonded to the carbon atom in the α-position. Include concepts. Examples of the substituent bonded to the α-position carbon atom include an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, and a hydroxyalkyl group. The α-position carbon atom of the acrylate ester is a carbon atom to which a carbonyl group is bonded unless otherwise specified.
“Exposure” is a concept including general irradiation of radiation.

  According to the present invention, a novel polymer compound that can be used as a base component of a positive resist composition, a compound useful as a monomer of the polymer compound, and a positive resist containing the polymer compound and excellent in lithography properties A composition and a resist pattern forming method using the positive resist composition can be provided.

≪Positive resist composition≫
The positive resist composition of the present invention (hereinafter sometimes referred to simply as “resist composition”) is a base component (A) (hereinafter referred to as “component (A)”) whose solubility in an alkaline developer is increased by the action of an acid. And an acid generator component (B) (hereinafter referred to as component (B)) that generates an acid upon irradiation with radiation.
In such a positive resist composition, when radiation is irradiated (exposed), an acid is generated from the component (B), and the solubility of the component (A) in an alkaline developer is increased by the action of the acid. Therefore, in the formation of the resist pattern, when selective exposure is performed on the resist film obtained using the positive resist composition, the solubility of the resist film in the alkaline developer in the exposed portion increases. Since the solubility of the unexposed portion in the alkaline developer does not change, a resist pattern can be formed by performing alkali development.
Here, the “base material component” is an organic compound having a film forming ability. As the substrate component, 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 a nano-level resist pattern is easily formed.
“Organic compounds having a molecular weight of 500 or more” used as the base component are roughly classified into non-polymers and polymers.
As the non-polymer, those having a molecular weight of 500 or more and less than 4000 are usually used. Hereinafter, a nonpolymer having a molecular weight of 500 or more and less than 4000 is referred to as a low molecular compound.
As the polymer, those having a molecular weight of 1000 or more are usually used. Hereinafter, a polymer having a molecular weight of 1000 or more is referred to as a polymer compound. In the case of a polymer compound, the “molecular weight” is a polystyrene-reduced mass average molecular weight measured by GPC (gel permeation chromatography). Hereinafter, the polymer compound may be simply referred to as “resin”.

<(A) component>
[Polymer Compound (A1)]
The polymer compound (A1) (hereinafter referred to as the component (A1)) has the structural unit (a0) represented by the general formula (a0).
In addition to the structural unit (a0), the component (A1) is composed of a structural unit (a2) derived from an acrylate ester containing a lactone-containing alicyclic group, and an acrylate ester containing an —SO ₂ -containing cyclic group. It is preferable to have at least one of the derived structural unit (a5) and the structural unit (a3) represented by the general formula (a3) described later.
In addition to the structural units (a0) and (a2), or in addition to the structural units (a0) and (a3), or in addition to the structural units (a0), (a2) and (a3), the component (A1) Or in addition to the structural units (a0) and (a5), or in addition to the structural units (a0), (a2) and (a5), or in addition to the structural units (a0), (a5) and (a3) Or in addition to the structural units (a0), (a2), (a5) and (a3), the structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group. Also good.
The proportion of the structural unit (a0) is 20 to 60 mol% and the proportion of the structural unit (a2) and / or the structural unit (a5) is 0 to 80 mol% with respect to all the structural units constituting the component (A1). The proportion of the structural unit (a3) is preferably 0 to 80 mol%.
Moreover, the sum of the ratio of the structural unit (a2) and / or the structural unit (a5) and the ratio of the structural unit (a3) to the total structural unit constituting the component (A1) is 40 to 80 mol%. It is preferable.

(Structural unit (a0))
The structural unit (a0) is a structural unit represented by the general formula (a0).
In general formula (a0), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.
The alkyl group having 1 to 5 carbon atoms of R is preferably a linear or branched alkyl group, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, Examples thereof include a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group.
The halogenated alkyl group having 1 to 5 carbon atoms of R is a group in which part or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and is most preferably a hydrogen atom or a methyl group in terms of industrial availability.
Further, R in formula (a0) and R in formula (a3) described later may be the same or different.

Wherein ^(a0), R 1, ^{R 2} are each independently a methyl group, an ethyl group or an isopropyl ^group, preferably R 1, ^{R 2} are identical, ^{R 1} and ^{R 2} is a methyl group Is particularly preferable because the effects of the present invention (resolution, LWR, film vergation suppression) are excellent.
In formula (a0), R ³ and R ⁴ are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.
The halogen atom for R ³ and R ^{4 is the same as} the halogen atom for R.
The alkyl group having 1 to 5 carbon atoms of R ³ and R ⁴ is the same as the alkyl group having 1 to 5 carbon atoms of R.
The halogenated alkyl group having 1 to 5 carbon atoms of R ³ and R ^{4 is} the same as the halogenated alkyl group having 1 to 5 carbon atoms of R.

In formula (a0), p is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and industrially particularly preferably 0.
In formula (a0), q is an integer of 0 to 4, preferably an integer of 0 to 2, more preferably 0 or 1, and industrially particularly preferably 0.
In the formula (a0), the bonding position of the naphthyl group to —C (R ¹ ) (R ² ) acrylate ester is not particularly limited. Bonding at the 2-position of the group is preferred. The presence of the space is considered to facilitate the deprotection reaction with the acid generated from the component (B), and is presumed to bring about the superior effect of the present invention.

  Specific examples of the structural unit (a0) are shown below. In the following formulas, R is the same as described above.

As the structural unit (a0), one type may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a0) in the component (A1) is preferably 20 to 60 mol%, more preferably 20 to 55 mol%, based on all the structural units constituting the component (A1). More preferably, it is 20-50 mol%, and 25-45 mol% is especially preferable. Lithographic characteristics such as reduction of outgas during exposure, reduction of film loss during development, sensitivity, LWR (line width roughness), etc. are improved by setting the value to the lower limit value or more. Can be balanced.

(Structural unit (a2))
The structural unit (a2) is a structural unit derived from an acrylate ester containing a lactone-containing cyclic group.
Here, the lactone-containing cyclic group refers to a cyclic group containing one ring (lactone ring) containing an —O—C (O) — structure. The lactone ring is counted as the first ring. When only the lactone ring is present, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure.
When the copolymer (A1) is used for forming a resist film, the lactone cyclic group of the structural unit (a2) increases the adhesion to the substrate of the resist film or has an affinity for a developer containing water. It is effective in enhancing the sex.

As the structural unit (a2), any unit can be used without any particular limitation.
Specifically, the lactone-containing monocyclic group is a group in which one hydrogen atom is removed from a 4- to 6-membered ring lactone, such as a group in which one hydrogen atom is removed from β-propiolactone, or γ-butyrolactone. Examples thereof include a group in which one hydrogen atom has been removed, and a group in which one hydrogen atom has been removed from δ-valerolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.
More specifically, examples of the structural unit (a2) include structural units represented by general formulas (a2-1) to (a2-5) shown below.

［式中、Ｒは、前記構成単位（ａ０）におけるＲと同じであり、Ｒ’はそれぞれ独立に水素原子、炭素数１〜５のアルキル基、炭素数１〜５のアルコキシ基または−ＣＯＯＲ”であり、Ｒ”は水素原子またはアルキル基であり、Ｒ^２９は単結合または２価の連結基であり、ｓ”は０または１〜２の整数であり、Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり、ｍは０または１の整数である。］

[Wherein, R is the same as R in the structural unit (a0), and R ′ is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or —COOR ”. R ″ is a hydrogen atom or an alkyl group, R ²⁹ is a single bond or a divalent linking group, s ″ is 0 or an integer of 1 to 2, and A ″ is an oxygen atom or a sulfur atom. It is a C1-C5 alkylene group which may contain, an oxygen atom or a sulfur atom, and m is an integer of 0 or 1. ]

R in the general formulas (a2-1) to (a2-5) is the same as R in the structural unit (a0).
Examples of the alkyl group having 1 to 5 carbon atoms of R ′ include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group.
Examples of the alkoxy group having 1 to 5 carbon atoms of R ′ include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group.
R ′ is preferably a hydrogen atom in view of industrial availability.
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
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 polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorinated alkyl group Specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Etc.
A ″ is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.
R ²⁹ is a single bond or a divalent linking group. The divalent linking group is the same as the divalent linking group described for Y ² in the general formula (a1-0-2) described later, and among them, an alkylene group and an ester bond (—C (= O) -O-) or a combination thereof is preferable. The alkylene group as the divalent linking group for R ²⁹ is more preferably a linear or branched alkylene group. Specifically, the same as the linear alkylene group and the branched alkylene group mentioned as the aliphatic hydrocarbon group for A in Y ² described later can be used.
s ″ is preferably an integer of 1 to 2.
Specific examples of the structural units represented by the general formulas (a2-1) to (a2-5) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

In the component (A1), as the structural unit (a2), one type may be used alone, or two or more types may be used in combination.
As the structural unit (a2), at least one selected from the group consisting of structural units represented by the general formulas (a2-1) to (a2-5) is preferable, and the general formulas (a2-1) to (a2) -3) At least 1 sort (s) selected from the group which consists of a structural unit represented by 3) is more preferable. Among these, from structural units represented by chemical formulas (a2-1-1), (a2-2-1), (a2-2-7), (a2-3-1) and (a2-3-5) It is preferable to use at least one selected from the group consisting of

  The proportion of the structural unit (a2) in the component (A1) is such that the resist film formed using the positive resist composition containing the component (A1) adheres to a support such as a substrate, and the developer. From the viewpoint of excellent affinity and the like, it is preferably 1 to 80 mol%, more preferably 10 to 70 mol%, based on all structural units constituting the component (A1).

(Structural unit (a3))
The structural unit (a3) is a structural unit represented by the following general formula (a3).

［式中、Ｒはそれぞれ独立に、水素原子、炭素数１〜５のアルキル基、または炭素数１〜５のハロゲン化アルキル基であり、Ｙ^１は２価の連結基である。］

[Wherein, R is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and Y ¹ is a divalent linking group. ]

In the formula (a3), examples of R include the same as R in the formula (a0), and a hydrogen atom or a methyl group is preferable.
In formula (a3), Y ¹ is a divalent linking group.
Preferred examples of the divalent linking group for Y ¹ include a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, and the like.

The divalent hydrocarbon group as Y ¹ is “having a substituent” means that part or all of the hydrogen atoms in the divalent hydrocarbon group are substituted with groups or atoms other than hydrogen atoms. means.

The hydrocarbon group may be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or only a carbon atom. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

More specifically, examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, and the like.
The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, still more preferably 1 to 5, and most preferably 1 to 2.

As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable. Specifically, a methylene group [—CH ₂ —], an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [ _{- (CH 2) 3 -]} , a tetramethylene group _{[- (CH 2) 4 -} ], a pentamethylene group _{[- (CH 2) 5 -} ], heptamethylene group _{[- (CH 2) 7 -} ], octamethylene Examples include a group [— (CH ₂ ) ₈ —], a nonamethylene group [— (CH ₂ ) ₉ —], a decamethylene group [— (CH ₂ ) ₁₀ —], and the like. Among these, a methylene group or an ethylene group is preferable.

As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ). _{2 -, - C (CH 3} ) (CH 2 CH 3) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; 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 CH _{3) 2} -CH ₂ - alkyl groups such _{as; -CH (CH 3) CH 2} CH 2 -, - CH 2 CH (CH 3) CH 2 - alkyl trimethylene groups such as; -CH _(CH 3) _{CH 2 CH 2 CH 2 -,} - CH 2 CH (CH 3) CH 2 CH 2 - And the like alkyl alkylene group such as an alkyl tetramethylene group of. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.
The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

Examples of the aliphatic hydrocarbon group containing a ring in the structure include a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), and a cyclic aliphatic hydrocarbon group as described above. And a group intervening in the middle of the chain aliphatic hydrocarbon group or the like.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. The monocyclic group is preferably a group in which two hydrogen atoms are removed from a C 3-6 monocycloalkane, and examples of the monocycloalkane include cyclopentane and cyclohexane.
As the polycyclic group, a group in which two hydrogen atoms are removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples include adamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane, and the like. It is done.
The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

Examples of the aromatic hydrocarbon group include aromatic monovalent aromatic hydrocarbon groups such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. A divalent aromatic hydrocarbon group obtained by further removing one hydrogen atom from a hydrocarbon;
An aromatic hydrocarbon group in which a part of carbon atoms constituting the ring of the divalent aromatic hydrocarbon group is substituted with a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom;
Benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, arylalkyl group such as 2-naphthylethyl group, etc. Aromatic hydrocarbon groups and the like removed.
Among them, the divalent aromatic hydrocarbon group is preferable, and an aromatic hydrocarbon group in which one hydrogen atom is further removed from a phenyl group, and an aromatic hydrocarbon group in which one hydrogen atom is further removed from a naphthyl group are particularly preferable. preferable.
The carbon number of the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.
The aromatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

The hetero atom in the “divalent linking group containing a hetero atom” is an atom other than a carbon atom and a hydrogen atom, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom.
As the divalent linking group containing a hetero atom, specifically, —O—, —C (═O) —, —C (═O) —O—, —O—C (═O) —, carbonate bond (—O—C (═O) —O—), —NH—, —NR ⁰⁴ (R ⁰⁴ is an alkyl group) —, —NH—C (═O) —, —C (═O) —NH—, ═N—, —S—, —SO ₂ —, —SO ₃ — and the like. Moreover, the combination etc. of these "divalent coupling groups containing a hetero atom" and a bivalent hydrocarbon group are mentioned.
Examples of the divalent hydrocarbon group include the same hydrocarbon groups that may have a substituent as described above, and a linear or branched aliphatic hydrocarbon group is preferable.

  In the present invention, the structural unit (a3) is preferably structural units (a3-1) to (a3-9) represented by the following formulas (a3-1) to (a3-9).

（式（ａ３−１）〜（ａ３−９）中、Ｒは前記に同じであり、ｊ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の整数であり、ｋは０または１である。また、式（ａ３−８）中のＲ^Ｎは、水素原子または炭素数１〜５のアルキル基である。）

(In the formulas (a3-1) to (a3-9), R is the same as described above, j is an integer of 1 to 3, t ′ is an integer of 1 to 3, and l is 1 to 5) is an integer, s is an integer of 1 to 3, k is 0 or 1. also, ^{R N} in the formula (a3-8) is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. )

In formula (a3-4), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group.
j is preferably 1, and a hydroxyl group bonded to the 3-position of adamantyl is particularly preferred.

In formula (3-5), t ′ is preferably 1. l is preferably 1. s is preferably 1. These preferably have a 2-norbornyl group or a 3-norbornyl group bonded to the terminal of the carboxyl group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.
Wherein (a3-8), ^{R N} is preferably a hydrogen atom.

Hereinafter, as the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
When the component (A1) has the structural unit (a3), the hydrophilicity of the component (A) is increased, the affinity with the developer is increased, the alkali solubility in the exposed area is improved, and the developability is improved. Contribute to.
The proportion of the structural unit (a3) in the component (A1) is preferably 1 to 80 mol% or more, more preferably 5 to 75 mol%, based on all the structural units constituting the component (A1). More preferred is ˜70 mol%.
Further, the sum of the proportion of the structural unit (a2) and / or the structural unit (a5) described later and the proportion of the structural unit (a3) with respect to all the structural units constituting the component (A1) (that is, the structural unit (a2) ) And the ratio of the structural unit (a3), the ratio of the structural unit (a5) and the ratio of the structural unit (a3), or the ratio of the structural unit (a2) and the structural unit (a5). ) And the ratio of the structural unit (a3)) are preferably 40 to 80 mol%, more preferably 50 to 80 mol%. By using the component (A1) having the structural unit (a0), the structural unit (a3), the structural unit (a2), and / or the structural unit (a5) at such a ratio, exposure is performed with the structural unit (a0). In addition to the improvement effect of lithography characteristics such as reduction of outgas, reduction of film thickness during development, reduction of film loss, sensitivity, LWR (line width roughness), etc., adhesion of a resist film to a support such as a substrate, The affinity with the developer can be improved.

(Structural unit (a1))
The structural unit (a1) is a structural unit derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group. In addition, even in the case of “a structural unit derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group”, the structural unit corresponding to the structural unit represented by the general formula (a0) is the structural unit (a0). Applicable and does not correspond to the structural unit (a1).
The acid dissociable, dissolution inhibiting group in the structural unit (a1) has an alkali dissolution inhibiting property that makes the entire component (A1) difficult to dissolve in an alkali developer before dissociation, and dissociates with an acid. This increases the solubility of the entire component in an alkaline developer, and those that have been proposed as acid dissociable, dissolution inhibiting groups for base resins for chemically amplified resists can be used. In general, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like; an acetal-type acid dissociable, dissolution inhibiting group such as an alkoxyalkyl group is widely known. .

Here, the “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group with a chain or cyclic alkyl group, and the carbonyloxy group (—C (═O ) -O-) shows a structure in which the tertiary carbon atom of the chain-like or cyclic alkyl group is bonded to the terminal oxygen atom. In this tertiary alkyl ester, when an acid acts, a bond is cut between an oxygen atom and a tertiary carbon atom.
The chain or cyclic alkyl group may have a substituent.
Hereinafter, a group that is acid dissociable by constituting a carboxy group and a tertiary alkyl ester is referred to as a “tertiary alkyl ester type acid dissociable, dissolution inhibiting group” for convenience.
Examples of the tertiary alkyl ester type acid dissociable, dissolution inhibiting group include an aliphatic branched acid dissociable, dissolution inhibiting group and an acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group.

Here, the term “aliphatic branched” in the claims and the specification means having a branched structure having no aromaticity.
The structure of the “aliphatic branched acid dissociable, dissolution inhibiting group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group.
The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
As the aliphatic branched acid dissociable, dissolution inhibiting group, a tertiary alkyl group having 4 to 8 carbon atoms is preferable, and specific examples include a tert-butyl group, a tert-pentyl group, and a tert-heptyl group. .

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the structural unit (a1) may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like. Is mentioned.
The basic ring structure excluding the substituent of the “aliphatic cyclic group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated. The “aliphatic cyclic group” is preferably a polycyclic group.
Examples of the aliphatic cyclic group include a monocycloalkane, a bicycloalkane, and a tricyclo which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom, or a fluorinated alkyl group. Examples thereof include groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as an alkane or tetracycloalkane. More specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. .

  Examples of the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group include a group having a tertiary carbon atom on the ring skeleton of a cyclic alkyl group. Specifically, 2-methyl-2 -Adamantyl group, 2-ethyl-2-adamantyl group, etc. are mentioned. Alternatively, in the structural units represented by the following general formulas (a1 ″ -1) to (a1 ″ -6), an adamantyl group such as a group bonded to an oxygen atom of a carbonyloxy group (—C (O) —O—) A group having an aliphatic cyclic group such as a cyclohexyl group, a cyclopentyl group, a norbornyl group, a tricyclodecyl group, or a tetracyclododecyl group and a branched alkylene group having a tertiary carbon atom bonded thereto. Can be mentioned.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基を示し；Ｒ^１５、Ｒ^１６はアルキル基（直鎖状、分岐鎖状のいずれでもよく、好ましくは炭素数１〜５である）を示す。］

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms; R ¹⁵ and R ¹⁶ are alkyl groups (both linear and branched); Well, preferably 1 to 5 carbon atoms). ]

  In the general formulas (a1 ″ -1) to (a1 ″ -6), the alkyl group having 1 to 5 carbon atoms or the halogenated alkyl group having 1 to 5 carbon atoms of R is bonded to the α-position of the acrylate ester. And the same as the alkyl group having 1 to 5 carbon atoms or the halogenated alkyl group having 1 to 5 carbon atoms.

The “acetal acid dissociable, dissolution inhibiting group” is generally bonded to an oxygen atom by substituting a hydrogen atom at the terminal of an alkali-soluble group such as a carboxy group or a hydroxyl group. When an acid is generated by exposure, the acid acts to break the bond between the acetal acid dissociable, dissolution inhibiting group and the oxygen atom to which the acetal acid dissociable, dissolution inhibiting group is bonded.
Examples of the acetal type acid dissociable, dissolution inhibiting group include a group represented by the following general formula (p1).

［式中、Ｒ^１’，Ｒ^２’はそれぞれ独立して水素原子または炭素数１〜５のアルキル基を表し、ｎは０〜３の整数を表し、Ｙは炭素数１〜５のアルキル基または脂肪族環式基を表す。］

[Wherein, R ¹ ′ and R ² ′ each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, n represents an integer of 0 to 3, and Y represents an alkyl group having 1 to 5 carbon atoms. Or represents an aliphatic cyclic group. ]

In the above formula, n is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
Examples of the alkyl group having 1 to 5 carbon atoms of R ¹ ′ and R ² ′ include those similar to the alkyl group having 1 to 5 carbon atoms of R, preferably a methyl group or an ethyl group, and most preferably a methyl group. preferable.
In the present invention, it is preferable that at least one of R ¹ ′ and R ² ′ is a hydrogen atom. That is, the acid dissociable, dissolution inhibiting group (p1) is preferably a group represented by the following general formula (p1-1).

［式中、Ｒ^１’、ｎ、Ｙは上記と同様である。］

[Wherein R ¹ ′, n and Y are the same as described above. ]

Examples of the alkyl group having 1 to 5 carbon atoms of Y include the same as the alkyl group having 1 to 5 carbon atoms of R.
The aliphatic cyclic group for Y can be appropriately selected from monocyclic or polycyclic aliphatic cyclic groups that have been proposed in a number of conventional ArF resists, for example, the “aliphatic ring” described above. Examples thereof are the same as those in the formula group.

  Examples of the acetal type acid dissociable, dissolution inhibiting group also include a group represented by the following general formula (p2).

［式中、Ｒ^１７、Ｒ^１８はそれぞれ独立して直鎖状または分岐鎖状のアルキル基または水素原子であり、Ｒ^１９は直鎖状、分岐鎖状または環状のアルキル基である。または、Ｒ^１７およびＲ^１９がそれぞれ独立に直鎖状または分岐鎖状のアルキレン基であって、Ｒ^１７の末端とＲ^１９の末端とが結合して環を形成していてもよい。］

[Wherein, R ¹⁷ and R ¹⁸ each independently represent a linear or branched alkyl group or a hydrogen atom, and R ¹⁹ represents a linear, branched or cyclic alkyl group. Alternatively, R ¹⁷ and R ¹⁹ may be each independently a linear or branched alkylene group, and the end of R ^{17 and} the end of R ¹⁹ may be bonded to form a ring. ]

In R ¹⁷ and R ¹⁸ , the alkyl group preferably has 1 to 15 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group. In particular, it is preferable that one of R ¹⁷ and R ¹⁸ is a hydrogen atom and the other is a methyl group.
R ¹⁹ is a linear, branched or cyclic alkyl group, preferably having 1 to 15 carbon atoms, and may be any of linear, branched or cyclic.
When R ¹⁹ is linear or branched, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ¹⁹ is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group, are included. Examples include a group excluding a hydrogen atom. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
In the above formula, R ¹⁷ and R ¹⁹ are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 5 carbon atoms), and the end of R ¹⁹ and R ¹⁷ The terminal may be bonded.
In this case, a cyclic group is formed by R ¹⁷ , R ¹⁹ , the oxygen atom to which R ¹⁹ is bonded, and the carbon atom to which the oxygen atom and R ¹⁷ are bonded. The cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

  As the structural unit (a1), one or more selected from the group consisting of structural units represented by the following general formula (a1-0-1) and structural units represented by the following general formula (a1-0-2): Is preferably used.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基を示し、Ｘ^１は酸解離性溶解抑制基を示す。］

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, and X ¹ represents an acid dissociable, dissolution inhibiting group. ]

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基を示し、Ｘ^２は酸解離性溶解抑制基を示し、Ｙ^２は２価の連結基を示す。］

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, X ² represents an acid dissociable, dissolution inhibiting group, and Y ² represents a divalent linkage. Indicates a group. ]

In the general formula (a1-0-1), the alkyl group having 1 to 5 carbon atoms or the halogenated alkyl group having 1 to 5 carbon atoms of R may be bonded to the α-position of the acrylate ester. It is the same as the alkyl group having ˜5 or the halogenated alkyl group having 1 to 5 carbon atoms.
X ¹ is not particularly limited as long as it is an acid dissociable, dissolution inhibiting group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable, dissolution inhibiting group and acetal type acid dissociable, dissolution inhibiting group. And tertiary alkyl ester type acid dissociable, dissolution inhibiting groups are preferred.

In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).

Examples of the divalent linking group for Y ² include an alkylene group, a divalent aliphatic cyclic group, and a divalent linking group containing a hetero atom.
As the aliphatic cyclic group, those similar to the explanation of the “aliphatic cyclic group” can be used except that a group in which two or more hydrogen atoms are removed is used.
When Y ² is an alkylene group, it is preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and 1 to 3 carbon atoms. Most preferably it is.
When Y ² is a divalent aliphatic cyclic group, a group in which two or more hydrogen atoms have been removed from cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane, or tetracyclododecane is particularly preferable. .
When Y ² is a divalent linking group containing a hetero atom, examples of the divalent linking group containing a hetero atom include —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O—, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group or an acyl group), —S—. , —S (═O) ₂ —, —S (═O) ₂ —O—, “—AO (oxygen atom) —B— (wherein A and B each independently have a substituent) And a combination of an alkylene group and a divalent linking group containing a hetero atom.

When Y ² is —NH—, the substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. It is particularly preferred that
When Y ² is “A—O—B”, A and B are each independently a divalent hydrocarbon group which may have a substituent.
The hydrocarbon group having “substituent” means that part or all of the hydrogen atoms in the hydrocarbon group are substituted with groups or atoms other than hydrogen atoms.

  The hydrocarbon group in A may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.

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

The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, still more preferably 2 to 5, and most preferably 2.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable. Specifically, a methylene group, an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [— (CH ₂ ) ₃ -], tetramethylene group _{[- (CH 2) 4 -} ], a pentamethylene group _{[- (CH 2) 5 -} ] , and the like.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ). _{2 -, - C (CH 3} ) (CH 2 CH 3) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as - 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 —; Alkyl trimethylene groups such as —CH (CH ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) CH ₂ —; —CH (CH ₃ ) CH ₂ CH ₂ CH ₂ —, —CH ₂ CH (CH _{3) CH} 2 CH ₂ - alkyl, such as alkyl tetramethylene group such as Such as an alkylene group, and the like. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.
The chain-like aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.

Examples of the aliphatic hydrocarbon group containing a ring include a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), and the cyclic aliphatic hydrocarbon group described above as a chain-like aliphatic group. And a group that is bonded to the terminal of the aromatic hydrocarbon group or intervenes in the middle of the chain-like aliphatic hydrocarbon group.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic group, a group in which two hydrogen atoms have been removed from a monocycloalkane having 3 to 6 carbon atoms is preferable, and examples of the monocycloalkane include cyclopentane and cyclohexane.
As the polycyclic group, a group in which two hydrogen atoms are removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, tetra And cyclododecane.
The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

  A is preferably a linear aliphatic hydrocarbon group, more preferably a linear alkylene group, still more preferably a linear alkylene group having 2 to 5 carbon atoms, and most preferably an ethylene group.

Examples of the hydrocarbon group for B include the same divalent hydrocarbon groups as those described above for A.
B is preferably a linear or branched aliphatic hydrocarbon group, particularly preferably a methylene group or an alkylmethylene group.
The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.

  More specifically, examples of the structural unit (a1) include structural units represented by the following general formulas (a1-1) to (a1-4).

［式中、Ｘ’は第３級アルキルエステル型酸解離性溶解抑制基を表し、Ｙは炭素数１〜５のアルキル基、または脂肪族環式基を表し；ｎは０〜３の整数を表し；Ｙ^２は２価の連結基を表し；Ｒは前記と同じであり、Ｒ^１’、Ｒ^２’はそれぞれ独立して水素原子または炭素数１〜５のアルキル基を表す。］

[Wherein, X ′ represents a tertiary alkyl ester-type acid dissociable, dissolution inhibiting group, Y represents an alkyl group having 1 to 5 carbon atoms or an aliphatic cyclic group; n represents an integer of 0 to 3; Y ² represents a divalent linking group; R is the same as defined above; R ¹ ′ and R ² ′ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ]

In the formula, X 'include the same tertiary alkyl ester-type acid dissociable, dissolution inhibiting groups as those described above for X ^{1.
R 1 ', R 2',} n, as the Y, respectively, ^{R 1} in the general formula listed in the description of "acetal-type acid dissociable, dissolution inhibiting group" described above ^{(p1) ', R 2'} , n, Y The same thing is mentioned.
The Y ^2, the same groups as those described above for ^{Y 2} in the general formula (a1-0-2).

Specific examples of the structural units represented by the general formulas (a1-1) to (a1-4) are shown below.
In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
Among these, the structural unit represented by general formula (a1-1), (a1-2) or (a1-3) is preferable, and specifically, (a1-1-1) to (a1-1-4). , (A1-1-20) to (a1-1-23), (a1-2-1) to (a1-2-24) and (a1-3-25) to (a1-3-28) It is more preferable to use at least one selected from the group.
Furthermore, as the structural unit (a1), in particular, the following general formula (a1-1-1-) including structural units of the formulas (a1-1-1) to (a1-1-3) and (a1-1-26) 01), formulas (a1-1-16) to (a1-1-17) and formulas (a1-1-20) to (a1-1-23) What is represented by (a1-1-02), which is represented by the following general formula (a1-3-01) including the structural units of formulas (a1-3-25) to (a1-3-26) The following general formula (a1-3-02) or the formulas (a1-3-29) to (a1-3-30) including the structural units of the formulas (a1-3-27) to (a1-3-28) The structural unit represented by the following general formula (a1-3-03) including the structural unit is also preferable.

[式中、Ｒはそれぞれ独立に水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基を示し、Ｒ^１１は炭素数１〜５のアルキル基を示す。Ｒ^１２は炭素数１〜７のアルキル基を示す。ｈは１〜６の整数を表す。]

[Wherein, R independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and R ¹¹ represents an alkyl group having 1 to 5 carbon atoms. R ¹² represents an alkyl group having 1 to 7 carbon atoms. h represents an integer of 1 to 6. ]

In general formula (a1-1-01), R is the same as defined above. The alkyl group having 1 to 5 carbon atoms of R ¹¹ is the same as the alkyl group having 1 to 5 carbon atoms in R, and is preferably a methyl group, an ethyl group, or an isopropyl group.

In general formula (a1-1-02), R is the same as defined above. The alkyl group having 1 to 5 carbon atoms of R ¹² is the same as the alkyl group having 1 to 5 carbon atoms in R, and is preferably a methyl group, an ethyl group, or an isopropyl group. h is preferably 1 or 2, and most preferably 2.

[式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基を示し；Ｒ^１４は炭素数１〜５のアルキル基であり、Ｒ^１３は水素原子またはメチル基であり、ａは１〜１０の整数である。]

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms; R ¹⁴ represents an alkyl group having 1 to 5 carbon atoms, and R ¹³ represents a hydrogen atom. Or it is a methyl group and a is an integer of 1-10. ]

[式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基を示し；Ｒ^１４は炭素数１〜５のアルキル基であり、Ｒ^１３は水素原子またはメチル基であり、ａは１〜１０の整数であり、ｎ’は１〜６の整数である。]

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms; R ¹⁴ represents an alkyl group having 1 to 5 carbon atoms, and R ¹³ represents a hydrogen atom. Or it is a methyl group, a is an integer of 1-10, n 'is an integer of 1-6. ]

［式中、Ｒは前記と同じであり、Ｙ^２’およびＹ^２”はそれぞれ独立して２価の連結基であり、Ｘ’は酸解離性溶解抑制基であり、ｎは０〜３の整数である。］

[Wherein, R is the same as defined above, Y ² ′ and Y ² ″ each independently represent a divalent linking group, X ′ represents an acid dissociable, dissolution inhibiting group, and n represents 0 to 3] It is an integer.]

In the general formulas (a1-3-01) to (a1-3-03), R is the same as described above.
R ¹³ is preferably a hydrogen atom.
Alkyl group of 1 to 5 carbon atoms for R ¹⁴ is the same as the alkyl group having 1 to 5 carbon atoms for R, a methyl group or an ethyl group is preferred.
n ′ is preferably 1 or 2, and most preferably 2.
a is preferably an integer of 1 to 8, more preferably an integer of 2 to 5, and most preferably 2.
As the divalent linking group for Y ² ′ and Y ² ″, the same groups as those described above for Y ² in formula (a1-3) can be given.
Y ² ′ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and even more preferably a linear alkylene group. Among these, a linear alkylene group having 1 to 5 carbon atoms is preferable, and a methylene group and an ethylene group are most preferable.
Y ² ″ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and still more preferably a linear alkylene group. A linear alkylene group of 1 to 5 is preferable, and a methylene group and an ethylene group are most preferable.
Examples of the acid dissociable, dissolution inhibiting group in X ′ include the same groups as described above, and are preferably tertiary alkyl ester type acid dissociable, dissolution inhibiting groups, and (i) the monovalent aliphatic cyclic group described above. A group having a tertiary carbon atom on the ring skeleton of the group is more preferable, and among them, the group represented by the general formula (1-1) is preferable.
n is an integer of 0 to 3, and n is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 1.

  In the case of having the structural unit (a1) in the component (A1), the proportion of the structural unit (a1) is preferably 1 to 50 mol%, and preferably 5 to 40 mol based on all structural units constituting the component (A1) % Is more preferable, and 10 to 30 mol% is more preferable. By setting it to the lower limit value or more, a pattern can be easily obtained when the resist composition is used, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

(Structural unit (a5))
The structural unit (a5) is a structural unit derived from an acrylate ester containing a —SO ₂ — containing cyclic group.
Here, -SO 2 _- and containing cyclic group, -SO 2 _- within the ring skeleton thereof shows a cyclic group containing a ring containing, counted ring as the first ring, the ring only In some cases, it is a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure. The —SO ₂ — containing cyclic group may be monocyclic or polycyclic.
The —SO ₂ — containing cyclic group is particularly preferably a cyclic group containing —O—SO ₂ — in its ring skeleton.
The —SO ₂ — containing cyclic group preferably has 3 to 30 carbon atoms, preferably 4 to 20 carbon atoms, more preferably 4 to 15 carbon atoms, and particularly preferably 4 to 12 carbon atoms. . However, the carbon number is the number of carbon atoms constituting the ring skeleton, and does not include the carbon number in the substituent.
The —SO ₂ — containing cyclic group may be an —SO ₂ — containing aliphatic cyclic group or an —SO ₂ — containing aromatic cyclic group. Preferably -SO ₂ - containing aliphatic cyclic group.
The —SO ₂ -containing aliphatic cyclic group includes at least a hydrogen atom from an aliphatic hydrocarbon ring in which a part of carbon atoms constituting the ring skeleton is substituted with —SO ₂ — or —O—SO ₂ —. One group is excluded. More specifically, a group obtained by removing at least one hydrogen atom from an aliphatic hydrocarbon ring in which —CH ₂ — constituting the ring skeleton is substituted with —SO ₂ —, —CH ₂ — constituting the ring And a group obtained by removing at least one hydrogen atom from an aliphatic hydrocarbon ring in which CH ₂ — is substituted with —O—SO ₂ —.
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 in which two hydrogen atoms are removed from a monocycloalkane having 3 to 6 carbon atoms. Examples of the monocycloalkane include cyclopentane and cyclohexane. As the polycyclic alicyclic hydrocarbon group, a group in which two hydrogen atoms have been removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane. , Tricyclodecane, tetracyclododecane and the like.

The —SO ₂ — containing cyclic group may have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), —COOR ″, —OC (═O) R ″, a hydroxyalkyl group, a cyano group, and the like. Is mentioned.
The alkyl group as the substituent is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. 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, 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.
The alkoxy group as the substituent is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, the group couple | bonded with the oxygen atom (-O-) to the alkyl group quoted as the alkyl group as the said substituent is mentioned.
Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group for the substituent include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.
Examples of the halogenated alkyl group as the substituent include groups in which part or all of the hydrogen atoms of the alkyl group mentioned as the alkyl group as the substituent are substituted with the halogen atom. As the halogenated alkyl group, a fluorinated alkyl group is preferable, and a perfluoroalkyl group is particularly preferable.
R ″ in the —COOR ″ and —OC (═O) R ″ is a hydrogen atom or a linear, branched or cyclic alkyl group having 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 polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorinated alkyl group More specifically, one or more hydrogen atoms are removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Group and the like.
The hydroxyalkyl group as the substituent is preferably one having 1 to 6 carbon atoms. Specifically, at least one of the hydrogen atoms of the alkyl group mentioned as the alkyl group as the substituent is substituted with a hydroxyl group. Group.
More specifically, examples of the —SO ₂ — containing cyclic group include groups represented by the following general formulas (5-1) to (5-4).

［式中、Ａ’は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり、ｚは０〜２の整数であり、Ｒ^６はアルキル基、アルコキシ基、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基またはシアノ基であり、Ｒ”は水素原子またはアルキル基である。］

[In the formula, A ′ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, z is an integer of 0 to 2, and R ⁶ is an alkyl group. , An alkoxy group, a halogenated alkyl group, a hydroxyl group, —COOR ″, —OC (═O) R ″, a hydroxyalkyl group or a cyano group, and R ″ is a hydrogen atom or an alkyl group.]

In the general formulas (5-1) to (5-4), A ′ represents an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (—O—) or a sulfur atom (—S—), An oxygen atom or a sulfur atom.
The alkylene group having 1 to 5 carbon atoms in A ′ is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group.
When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include a group in which —O— or —S— is interposed between the terminal or carbon atoms of the alkylene group, such as —O—CH _{2. -, - CH 2 -O-CH} 2 -, - S-CH 2 -, - CH 2 -S-CH 2 - , and the like.
A ′ is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.
z may be any of 0 to 2, and is most preferably 0.
When z is 2, the plurality of R ⁶ may be the same or different.
As the alkyl group, alkoxy group, halogenated alkyl group, —COOR ″, —OC (═O) R ″, and hydroxyalkyl group in R ⁶ , the —SO ₂ — containing cyclic group has the above-mentioned, respectively. And the same alkyl groups, alkoxy groups, halogenated alkyl groups, —COOR ″, —OC (═O) R ″, and hydroxyalkyl groups as those which may be substituted.
Specific examples of cyclic groups represented by the general formulas (5-1) to (5-4) are shown below. In the formula, “Ac” represents an acetyl group.

As the —SO ₂ — containing cyclic group, among the above, the group represented by the general formula (5-1) is preferable, and the chemical formulas (5-1-1), (5-1-18), ( It is more preferable to use at least one selected from the group consisting of groups represented by any of 5-3-1) and (5-4-1), and represented by the chemical formula (5-1-1). Are most preferred.

  More specifically, examples of the structural unit (a5) include structural units represented by general formula (a5-0) shown below.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^５は−ＳＯ_２−含有環式基であり、Ｒ^２９は単結合または２価の連結基である。］

[Wherein, 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, R ⁵ is an —SO ₂ -containing cyclic group, and R ²⁹ is a single bond] Or it is a bivalent coupling group. ]

In formula (a5-0), R is the same as defined above.
R ⁵ is the same as the —SO ₂ — containing cyclic group mentioned above.
R ²⁹ may be a single bond or a divalent linking group. Since it is excellent in the effect of this invention, it is preferable that it is a bivalent coupling group.
The divalent linking group for R ²⁹ is not particularly limited. For example, as the divalent linking group for Y ² in the general formula (a1-0-2) mentioned in the description of the structural unit (a1). The thing similar to what was mentioned is mentioned. Among these, those containing an alkylene group or an ester bond (—C (═O) —O—) are preferable.
The alkylene group is preferably a linear or branched alkylene group. Specifically, the same as the linear alkylene group and the branched alkylene group mentioned as the aliphatic hydrocarbon group for Y ² can be used.
As the divalent linking group containing an ester bond, in particular, the general formula: —Y ³ —C (═O) —O— [wherein Y ³ is a divalent linking group. ] Is preferable. That is, the structural unit (a5) is preferably a structural unit represented by the following general formula (a5-0-1).

［式中、ＲおよびＲ^５はそれぞれ前記と同様であり、Ｙ^３は２価の連結基である。］

[Wherein, R and R ⁵ are the same as defined above, and Y ³ is a divalent linking group. ]

Y ³ is not particularly limited, and for example, the same as the divalent linking group in Y ² in the general formula (a1-0-2) mentioned in the description of the structural unit (a1). Things.
The divalent linking group for Y ³ is preferably a linear or branched alkylene group, a divalent alicyclic hydrocarbon group, or a divalent linking group containing a hetero atom.
Examples of the linear or branched alkylene group, divalent alicyclic hydrocarbon group, and divalent linking group containing a hetero atom include the linear or branched groups mentioned above as preferred for Y ^2. Examples thereof include the same chain alkylene groups, divalent alicyclic hydrocarbon groups, and divalent linking groups containing a hetero atom.
Among these, a linear or branched alkylene group or a divalent linking group containing an oxygen atom as a hetero atom is preferable.
As the linear alkylene group, a methylene group or an ethylene group is preferable, and a methylene group is particularly preferable.
As the branched alkylene group, an alkylmethylene group or an alkylethylene group is preferable, and —CH (CH ₃ ) —, —C (CH ₃ ) ₂ — or —C (CH ₃ ) ₂ CH ₂ — is particularly preferable.
The divalent linking group containing an oxygen atom is preferably a divalent linking group containing an ether bond or an ester bond, and the above formulas -A-O-B-,-[A-C (= O) -O] _m A group represented by —B— or —A—O—C (═O) —B— is more preferable.
Among them, a group represented by the formula -A-O-C (= O ) -B- is _preferably, - represented by _{- (CH 2) f -C (} = O) -O- (CH 2) g1 The group is particularly preferred. f is an integer of 1 to 5, and 1 or 2 is preferable. g1 is an integer of 1 to 5, and 1 or 2 is preferable.

  As the structural unit (a5), a structural unit represented by general formula (a5-0-1-11) or (a5-0-1-12) shown below is particularly desirable, and the structural unit (a5-0-1-12) is preferred. ) Is more preferable.

［式中、Ｒ、Ａ’、Ｒ^６、ｚおよびＹ^３はそれぞれ前記と同じである。］

[Wherein, R, A ′, R ⁶ , z and Y ³ are the same as defined above. ]

In formula (a5-0-1-11), A ′ is preferably a methylene group, an oxygen atom (—O—) or a sulfur atom (—S—).
Y ³ is preferably a linear or branched alkylene group or a divalent linking group containing an oxygen atom. As the linear or branched alkylene group for Y ^{3 and} the divalent linking group containing an oxygen atom, the linear or branched alkylene group mentioned above and a divalent linking group containing an oxygen atom, respectively, Examples are the same as the linking group.
As the structural unit represented by the formula (a5-0-1-12), a structural unit represented by the following general formula (a5-0-1-12a) or (a5-0-1-12b) is particularly preferable. preferable.

［式中、ＲおよびＡ’はそれぞれ前記と同じであり、ｃ〜ｅはそれぞれ独立に１〜３の整数である。］

[Wherein, R and A ′ are the same as defined above, and c to e are each independently an integer of 1 to 3.] ]

As the structural unit (a5), one type may be used alone, or two or more types may be used in combination.
When the structural unit (a5) is contained in the component (A1), the proportion of the structural unit (a5) is preferably 1 to 80 mol% with respect to the total of all the structural units constituting the component (A1). 80 mol% is more preferable, 10-70 mol% is further more preferable, and 15-65 mol% is especially preferable. By setting it to the lower limit value or more, the effect of containing the structural unit (a5) can be sufficiently obtained, and by setting it to the upper limit value or less, it is possible to balance with other structural units, and the sensitivity, LWR (line width) Various lithography characteristics such as roughness are improved.

(Other structural units)
The component (A1) may contain other structural units other than the structural units (a0) to (a3) and (a5) as long as the effects of the present invention are not impaired.
The other structural unit is not particularly limited as long as it is another structural unit that is not classified into the above structural units (a0) to (a3) and (a5). For ArF excimer laser, for KrF excimer laser, Many things conventionally known as what is used for resin for resists, such as for EB (electron beam) and EUV (extreme ultraviolet rays), can be used.

The component (A1) is preferably a copolymer having the structural unit (a0).
Examples of the copolymer include a copolymer composed of the structural unit (a0) and the structural unit (a3); a copolymer composed of the structural unit (a0) and the structural unit (a2); a structural unit (a0) and the structural unit. Copolymer comprising unit (a5); copolymer comprising structural unit (a0), structural unit (a2) and structural unit (a3); structural unit (a0), structural unit (a3) and structural unit (a5) A copolymer comprising the structural unit (a0), the structural unit (a2) and the structural unit (a5); a copolymer comprising the structural unit (a0), the structural unit (a3) and the structural unit (a1). Copolymer: copolymer composed of structural unit (a0), structural unit (a2) and structural unit (a1); copolymer composed of structural unit (a0), structural unit (a5) and structural unit (a1); structural unit (A0), structure Copolymer comprising unit (a2), structural unit (a3) and structural unit (a1); copolymer comprising structural unit (a0), structural unit (a2), structural unit (a3) and structural unit (a5) A copolymer comprising the structural unit (a0), the structural unit (a2), the structural unit (a5) and the structural unit (a1); the structural unit (a0), the structural unit (a3), the structural unit (a5) and the structural unit Examples include a copolymer comprising (a1); a copolymer comprising the structural unit (a0), the structural unit (a2), the structural unit (a3), the structural unit (a1) and the structural unit (a5).
In the present invention, the component (A1) is particularly preferably a copolymer having structural units represented by the following general formulas (A1-11) to (A1-14), respectively.

［式中、Ｒ、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、ｐおよびｑはそれぞれ前記と同じであり、式中の複数のＲはそれぞれ同じであっても異なっていてもよい。］

[Wherein, R, R ¹ , R ² , R ³ , R ⁴ , p and q are the same as defined above, and the plurality of R in the formula may be the same or different. ]

［式中、Ｒ、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^２９、Ｒ’、ｐ、ｑ、ｊおよびｓ”はそれぞれ前記と同じであり、式中の複数のＲはそれぞれ同じであっても異なっていてもよい。］

[Wherein, R, R ¹ , R ² , R ³ , R ⁴ , R ²⁹ , R ′, p, q, j and s ″ are the same as defined above, and a plurality of R in the formula are the same It may or may not be.]

［式中、Ｒ、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、ｐ、ｑ、ｊ、ｅおよびＡ’はそれぞれ前記と同じであり、式中の複数のＲはそれぞれ同じであっても異なっていてもよい。］

[Wherein, R, R ¹ , R ² , R ³ , R ⁴ , p, q, j, e and A ′ are the same as defined above, and a plurality of R in the formula are the same or different. It may be. ]

［式中、Ｒ、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、ｐ、ｑ、ｅおよびＡ’はそれぞれ前記と同じであり、式中の複数のＲはそれぞれ同じであっても異なっていてもよい。］

[Wherein, R, R ¹ , R ² , R ³ , R ⁴ , p, q, e and A ′ are the same as defined above, and a plurality of R in the formula are the same or different. Also good. ]

The mass average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography (GPC)) is not particularly limited, preferably 1000 to 50000, more preferably 1500 to 30000, 2000 to 2000 20000 is more preferable. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is above the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Moreover, the dispersity (Mw / Mn) of the component (A1) is not particularly limited, but is preferably 1.0 to 5.0, and more preferably 1.0 to 3.5. Mn represents a number average molecular weight.

The component (A1) is a known monomer using a radical polymerization initiator such as dimethyl-2,2-azobis (2-methylpropionate) or azobisisobutyronitrile as a monomer for deriving each structural unit. It can be obtained by polymerizing by radical polymerization or the like.
Further, for the component (A1), in the polymerization, a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination, so that the terminal A —C (CF ₃ ) ₂ —OH group may be introduced into the. As described above, a copolymer introduced with a hydroxyalkyl group in which a part of hydrogen atoms of the alkyl group is substituted with a fluorine atom reduces development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing

  As the monomer for deriving each structural unit, a commercially available monomer may be used, or a monomer produced using a known method may be used.

In the component (A), 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, still more preferably 75% by mass or more, and 100% by mass with respect to the total mass of the component (A). It may be. When the ratio is 25% by mass or more, the lithography characteristics and the like are improved.

The positive resist composition of the present invention does not correspond to the component (A1) as the component (A), but is a base material component (hereinafter referred to as “component (A2)”) that increases the solubility in an alkaline developer by the action of an acid. .) May be contained.
The component (A2) is preferably a low molecular compound having a molecular weight of 500 or more and less than 2500 and having an acid dissociable, dissolution inhibiting group and a hydrophilic group as exemplified in the description of the component (A1). Specifically, a compound in which a part of hydrogen atoms of a hydroxyl group of a compound having a plurality of phenol skeletons is substituted with the acid dissociable, dissolution inhibiting group can be mentioned.
The component (A2) is, for example, a part of the hydrogen atom of the hydroxyl group of a low molecular weight phenol compound known as a sensitizer in a non-chemically amplified g-line or i-line resist or a heat resistance improver. Those substituted with a soluble dissolution inhibiting group are preferred and can be arbitrarily used.
Examples of such low molecular weight phenol compounds include bis (4-hydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) methane, 2- (4-hydroxyphenyl) -2- (4′-hydroxyphenyl). ) Propane, 2- (2,3,4-trihydroxyphenyl) -2- (2 ′, 3 ′, 4′-trihydroxyphenyl) propane, tris (4-hydroxyphenyl) methane, bis (4-hydroxy-) 3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3, 4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3,4-dihydroxyph Phenylmethane, bis (4-hydroxy-3-methylphenyl) -3,4-dihydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl- 4-hydroxy-6-methylphenyl) -3,4-dihydroxyphenylmethane, 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, Examples include, but are not limited to, 2-6 nuclei of formalin condensates of phenols such as phenol, m-cresol, p-cresol, and xylenol. In particular, a phenol compound having 2 to 6 triphenylmethane skeletons is preferable because of excellent resolution and LWR.
The acid dissociable, dissolution inhibiting group is not particularly limited, and examples thereof include those described above.
(A2) A component may be used individually by 1 type and may be used in combination of 2 or more type.

In the positive resist composition of the present invention, as the component (A), one type may be used alone, or two or more types may be used in combination.
Among these, as the component (A), it is preferable to contain the component (A1).
In the positive resist composition of the present invention, the content of the component (A) may be adjusted according to the resist film thickness to be formed.

<(B) component>
The component (B) is not particularly limited, and those that have been proposed as acid generators for chemically amplified resists can be used. Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, poly (bissulfonyl) diazomethanes, and the like. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.
As the onium salt acid generator, for example, a compound represented by the following general formula (b-1) or (b-2) can be used.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”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またはアルキル基を表し；式（ｂ−１）におけるＲ^１”〜Ｒ^３”のうち、いずれか２つが相互に結合して式中のイオウ原子と共に環を形成してもよく；Ｒ^４”は、置換基を有していてもよいアルキル基、ハロゲン化アルキル基、アリール基またはアルケニル基を表し；Ｒ^１”〜Ｒ^３”のうち少なくとも１つはアリール基を表し、Ｒ^５”〜Ｒ^６”のうち少なくとも１つはアリール基を表す。］

[Wherein, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group which may have a substituent; R in the formula (b-1) Any one of ¹ ″ to R ³ ″ may be bonded to each other to form a ring together with the sulfur atom in the formula; R ⁴ ″ represents an alkyl group which may have a substituent, a halogen atom; An alkyl group, an aryl group or an alkenyl group; at least one of R ¹ ″ to R ³ ″ represents an aryl group and at least one of R ⁵ ″ to R ⁶ ″ represents an aryl group.]

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group which may have a substituent. In addition, any two of R ¹ ″ to R ³ ″ in formula (b-1) may be bonded to each other to form a ring together with the sulfur atom in the formula.
Further, at least one of R ¹ ″ to R ³ ″ represents an aryl group. Of R ¹ ″ to R ³ ″, two or more are preferably aryl groups, and most preferably all R ¹ ″ to R ³ ″ are aryl groups.

The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and examples thereof include an aryl group having 6 to 20 carbon atoms. The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The aryl group may have a substituent. “Having a substituent” means that part or all of the hydrogen atoms of the aryl group are substituted with a substituent, and examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, An alkoxyalkyloxy group, —O—R ⁵⁰ —C (═O) — (O) _n —R ⁵¹ , wherein R ⁵⁰ is an alkylene group or a single bond, and R ⁵¹ is an acid dissociable group or an acid non-dissociating group. N is 0 or 1. ] Etc. are mentioned.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Is most preferred.
As the alkoxy group that may be substituted for the hydrogen atom of the aryl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, A tert-butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
The halogen atom that may be substituted with the hydrogen atom of the aryl group is preferably a fluorine atom.

As the alkoxyalkyloxy group in which the hydrogen atom of the aryl group may be substituted, for example, —O—C (R ⁴⁷ ) (R ⁴⁸ ) —O—R ^{49 wherein} R ⁴⁷ and R ⁴⁸ are each It is independently a hydrogen atom or a linear or branched alkyl group, R ⁴⁹ is an alkyl group, and R ⁴⁸ and R ⁴⁹ may be bonded to each other to form one ring structure. However, at least one of R ⁴⁷ and R ⁴⁸ is a hydrogen atom. ].
In R ⁴⁷ and R ⁴⁸ , the alkyl group preferably has 1 to 5 carbon atoms, preferably an ethyl group or a methyl group, and most preferably a methyl group.
One of R ⁴⁷ and R ⁴⁸ is preferably a hydrogen atom, the other is preferably a hydrogen atom or a methyl group, and both R ⁴⁷ and R ⁴⁸ are particularly preferably hydrogen atoms.
The alkyl group for R ⁴⁹ preferably has 1 to 15 carbon atoms and may be linear, branched or cyclic.
The linear or branched alkyl group for R ⁴⁹ preferably has 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group. Can be mentioned.
The cyclic alkyl group for R ⁴⁹ preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms.
Specifically, monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, etc., which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group, etc. And a group obtained by removing one or more hydrogen atoms from the polycycloalkane. Examples of the monocycloalkane include cyclopentane and cyclohexane. Examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
R ⁴⁸ and R ⁴⁹ may be bonded to each other to form one ring structure. In this case, a cyclic group is formed by R ⁴⁸ , R ⁴⁹ , the oxygen atom to which R ⁴⁹ is bonded, and the carbon atom to which the oxygen atom and R ⁴⁸ are bonded. The cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring.

In —O—R ⁵⁰ —C (═O) — (O) _n —R ⁵¹ in which the hydrogen atom of the aryl group may be substituted, the alkylene group for R ⁵⁰ is a linear or branched alkylene Group is preferable, and the number of carbon atoms is preferably 1 to 5. Examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a 1,1-dimethylethylene group.
The acid dissociable group in R ⁵¹ is not particularly limited as long as it is an organic group that can be dissociated by the action of an acid (an acid generated from the component (B) at the time of exposure). For example, the acid dissociable group is exemplified in the description of the component (A). Examples include the same acid dissociable, dissolution inhibiting groups. Among them, the tertiary alkyl ester type is preferable.
The acid non-dissociable group for R ⁵¹ is preferably a decyl group, a tricyclodecanyl group, an adamantyl group, a 1- (1-adamantyl) methyl group, a tetracyclododecanyl group, an isobornyl group, or a norbornyl group.

The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, linear C1-10, branched or cyclic alkyl group, and the like. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.
The alkyl group may have a substituent. “Having a substituent” means that part or all of the hydrogen atoms of the alkyl group are substituted with a substituent, and the substituent may be a substituent that the aryl group may have. The thing similar to what was mentioned as a group is mentioned.

In formula (b-1), any two of R ¹ ″ to R ³ ″ may be bonded to each other to form a ring together with the sulfur atom in the formula. The ring may be saturated or unsaturated. The ring may be monocyclic or polycyclic. For example, when one or both of the two forming a ring is a cyclic group (cyclic alkyl group or aryl group), a polycyclic ring (fused ring) is formed when they are combined.
When two of R ¹ ″ to R ³ ″ are combined to form a ring, one ring containing a sulfur atom in the ring skeleton in the formula is a 3 to 10 membered ring including the sulfur atom. Of these, a 5- to 7-membered ring is particularly preferable.
Specific examples of the ring formed by combining two of R ¹ ″ to R ³ ″ include benzothiophene, dibenzothiophene, 9H-thioxanthene, thioxanthone, thianthrene, phenoxathiin, tetrahydrothiophenium, tetrahydro Examples include thiopyranium.
When any two of R ¹ ″ to R ³ ″ are bonded to each other to form a ring together with the sulfur atom in the formula, the remaining one is preferably an aryl group.

Of the cation moiety of the compound represented by formula (b-1), when R ¹ ″ to R ³ ″ are all phenyl groups that may have a substituent, that is, the cation moiety is triphenylsulfonium. Preferable specific examples in the case of having a skeleton include, for example, cation moieties represented by the following formulas (I-1-1) to (I-1-14).

  Moreover, what substituted a part or all of the phenyl group in these cation parts with the naphthyl group which may have a substituent is mentioned as a preferable thing. Of the three phenyl groups, 1 or 2 is preferably substituted with the naphthyl group.

Moreover, among the cation part of the compound represented by the formula (b-1), any two of R ¹ ″ to R ³ ″ are bonded to each other to form a ring together with the sulfur atom in the formula. Preferable specific examples of the case include, for example, cation moieties represented by the following formulas (I-11-10) to (I-11-13).

［式中、Ｒ^９は、置換基を有していてもよいフェニル基、置換基を有していてもよいナフチル基または炭素数１〜５のアルキル基であり、Ｒ^１０は、置換基を有していてもよいフェニル基、置換基を有していてもよいナフチル基、炭素数１〜５のアルキル基、炭素数１〜５のアルコキシ基または水酸基であり、ｕは１〜３の整数である。］

[Wherein, R ⁹ is a phenyl group which may have a substituent, a naphthyl group which may have a substituent or an alkyl group having 1 to 5 carbon atoms, and R ¹⁰ represents a substituent. A phenyl group which may have, a naphthyl group which may have a substituent, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms or a hydroxyl group, u is an integer of 1 to 3 It is. ]

［式中、Ｒ^４１〜Ｒ^４６はそれぞれ独立してアルキル基、アセチル基、アルコキシ基、カルボキシ基、水酸基またはヒドロキシアルキル基であり；ｎ_１〜ｎ_５はそれぞれ独立して０〜３の整数であり、ｎ_６は０〜２の整数である。］

[Wherein R ^{41 to} R ⁴⁶ are each independently an alkyl group, acetyl group, alkoxy group, carboxy group, hydroxyl group or hydroxyalkyl group; n _{1 to} n ₅ are each independently an integer of 0 to 3; There, _{n 6} is an integer of 0-2. ]

In the formulas (I-11-10) to (I-11-11), in R ^{9 to} R ¹⁰ , the substituent that the phenyl group or naphthyl group may have may be represented by R ¹ ″ to R ³ ″. The thing similar to what was mentioned as a substituent which an aryl group may have is mentioned. As the substituent that the alkyl group have the ^{R 9 ~R 10, R 1 "} ~R 3" are the same as those of the substituent which may be alkyl groups have in the Can be mentioned.
u is an integer of 1 to 3, and 1 or 2 is most preferable.
In formulas (I-11-12) to (I-11-13), in R ^{41 to} R ⁴⁶ , the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, and in particular, a linear or branched alkyl group A group is more preferable, and a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, or a tert-butyl group is particularly preferable.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a linear or branched alkoxy group, and particularly preferably a methoxy group or an ethoxy group.
The hydroxyalkyl group is preferably a group in which one or more hydrogen atoms in the alkyl group are substituted with a hydroxy group, and examples thereof include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.
When the symbols n _{1 to} n ₆ attached to R ^{41 to} R ⁴⁶ are integers of 2 or more, the plurality of R ^{41 to} R ⁴⁶ may be the same or different.
n ₁ is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.
n ₂ and n ₃ are preferably each independently 0 or 1, more preferably 0.
n ₄ is preferably 0 to 2, more preferably 0 or 1.
n ₅ is preferably 0 or 1, more preferably 0.
n ₆ is preferably 0 or 1, more preferably 1.

In formulas (b-1) to (b-2), R ⁴ ″ represents an alkyl group, a halogenated alkyl group, an aryl group, or an alkenyl group which may have a substituent.
The alkyl group for R ⁴ ″ may be linear, branched or cyclic.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
Examples of the halogenated alkyl group for R ⁴ ″ include groups in which part or all of the hydrogen atoms of the linear, branched, or cyclic alkyl group have been substituted with halogen atoms. A fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
In the halogenated alkyl group, the ratio of the number of halogen atoms to the total number of halogen atoms and hydrogen atoms contained in the halogenated alkyl group (halogenation rate (%)) is preferably 10 to 100%. 50 to 100% is preferable, and 100% is most preferable. The higher the halogenation rate, the better the acid strength.
The aryl group for R ⁴ ″ is preferably an aryl group having 6 to 20 carbon atoms.
The alkenyl group in R ⁴ ″ is preferably an alkenyl group having 2 to 10 carbon atoms.
In the above R ⁴ ″, “optionally substituted” means one of hydrogen atoms in the linear, branched or cyclic alkyl group, halogenated alkyl group, aryl group, or alkenyl group. It means that part or all may be substituted with a substituent (an atom or group other than a hydrogen atom).
The number of substituents in R ⁴ ″ may be one or two or more.

Examples of the substituent include, for example, a halogen atom, a hetero atom, an alkyl group, a formula: XQ ^1- [where Q ¹ is a divalent linking group containing an oxygen atom, and X has a substituent. And a hydrocarbon group having 3 to 30 carbon atoms. ] Etc. which are represented by these.
Examples of the halogen atom and alkyl group include the same groups as those described above for R ⁴ ″ as the halogen atom and alkyl group in the halogenated alkyl group.
Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom.

X-Q 1 ^- In the group represented by, Q ¹ represents a divalent linking group containing an oxygen atom.
Q ¹ may contain an atom other than an oxygen atom. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, oxygen atoms, sulfur atoms, and nitrogen atoms.
Examples of the divalent linking group containing an oxygen atom include an oxygen atom (ether bond; —O—), an ester bond (—C (═O) —O—), and an amide bond (—C (═O) —NH. -), A carbonyl group (-C (= O)-), a non-hydrocarbon oxygen atom-containing linking group such as a carbonate bond (-O-C (= O) -O-); the non-hydrocarbon oxygen atom Examples include a combination of a containing linking group and an alkylene group.
Examples of the combination include —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) —O—R ⁹³ —, —C (═O) —O—R. ⁹³ —O—C (═O) — (wherein R ^{91 to} R ⁹³ are each independently an alkylene group).
The alkylene group for R ^{91 to} R ⁹³ is preferably a linear or branched alkylene group, and the alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. preferable.
Specific examples of the alkylene group include a methylene group [—CH ₂ —]; —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ) ₂ —, —C ( _{CH 3) (CH 2 CH 3} ) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; 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 —, Alkylethylene groups such as —CH (CH ₂ CH ₃ ) CH ₂ —; trimethylene group (n-propylene group) [—CH ₂ CH ₂ CH ₂ —]; —CH (CH ₃ ) CH ₂ CH ₂ —, —CH _{2 CH (CH 3) CH 2} - alkyl trimethylene group and the like; Toramechiren group _{[-CH 2 CH 2 CH 2 CH} 2 -]; - CH (CH 3) CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 - alkyl tetramethylene group and the like; penta And methylene group [—CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ —] and the like.
Q ¹ is preferably a divalent linking group containing an ester bond or an ether bond. Among them, —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) — O—, —C (═O) —O—R ⁹³ — or —C (═O) —O—R ⁹³ —O—C (═O) — is preferred.

In the group represented by XQ ^1- , the hydrocarbon group of X may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.
The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and most preferably 6 to 12. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic hydrocarbon group include a hydrogen atom from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Aryl groups such as aryl group, benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., from which one is removed. The number of carbon atoms in the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.
The aromatic hydrocarbon group may have a substituent. For example, a part of carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group may be substituted with a hetero atom, and the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group is substituted with the substituent. May be.
Examples of the former include heteroaryl groups in which some of the carbon atoms constituting the ring of the aryl group are substituted with heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and aromatic hydrocarbons in the arylalkyl groups. Examples include heteroarylalkyl groups in which some of the carbon atoms constituting the ring are substituted with the above heteroatoms.
Examples of the substituent of the aromatic hydrocarbon group in the latter example include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group as a substituent of the aromatic hydrocarbon group is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. preferable.
The alkoxy group as a substituent of the aromatic hydrocarbon group is preferably an alkoxy group having 1 to 5 carbon atoms, and is a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, tert- A butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent of the aromatic hydrocarbon group include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

The aliphatic hydrocarbon group for X may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
In X, the aliphatic hydrocarbon group may have a part of the carbon atoms constituting the aliphatic hydrocarbon group substituted by a substituent containing a hetero atom, and the hydrogen atom constituting the aliphatic hydrocarbon group May be substituted with a substituent containing a hetero atom.
The “heteroatom” in X is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The “substituent containing a heteroatom” (hereinafter sometimes referred to as a heteroatom-containing substituent) may be composed of only the heteroatom, or may be a group containing a group other than the heteroatom or an atom. May be.

Examples of the hetero atom-containing substituent that may substitute a part of carbon atoms constituting the aliphatic hydrocarbon group include —O—, —C (═O) —O—, —C (═O) —. , —O—C (═O) —O—, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group or an acyl group), —S. -, -S (= O) _2- , -S (= O) _2- O- and the like. In the case of -NH-, the substituent (alkyl group, acyl group, etc.) that may substitute for H preferably has 1 to 10 carbon atoms, and more preferably 1 to 8 carbon atoms. Particularly preferably, it has 1 to 5 carbon atoms.
When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.

Examples of the hetero atom-containing substituent that may substitute part or all of the hydrogen atoms constituting the aliphatic hydrocarbon group include a halogen atom, an alkoxy group, a hydroxyl group, —C (═O) —R ⁸⁰ [ R ⁸⁰ is an alkyl group. ], -COOR ⁸¹ [R ⁸¹ is a hydrogen atom or an alkyl group. ], Halogenated alkyl groups, halogenated alkoxy groups, amino groups, amide groups, nitro groups, oxygen atoms (= O), sulfur atoms, sulfonyl groups (SO ₂ ) and the like.
Examples of the halogen atom as the heteroatom-containing substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
The alkyl group in the alkoxy group as the heteroatom-containing substituent may be linear, branched or cyclic, or a combination thereof. The carbon number is preferably 1-30. When the alkyl group is linear or branched, the carbon number is preferably 1-20, more preferably 1-17, still more preferably 1-15, 10 is particularly preferred. Specific examples thereof include those similar to the specific examples of the linear or branched saturated hydrocarbon group exemplified below. When the alkyl group is cyclic (when it is a cycloalkyl group), the carbon number is preferably 3 to 30, more preferably 3 to 20, still more preferably 3 to 15, and 4 to 12 carbon atoms. It is particularly preferred that the number of carbon atoms is 5-10. The alkyl group may be monocyclic or polycyclic. Specific examples include groups in which one or more hydrogen atoms have been removed from monocycloalkane, groups in which one or more hydrogen atoms have been removed from polycycloalkanes such as bicycloalkane, tricycloalkane, and tetracycloalkane. . Specific examples of the monocycloalkane include cyclopentane and cyclohexane. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. In these cycloalkyl groups, some or all of the hydrogen atoms bonded to the ring may or may not be substituted with a substituent such as a fluorine atom or a fluorinated alkyl group.
In —C (═O) —R ⁸⁰ and —COOR ⁸¹ as the hetero atom-containing substituent, the alkyl group in R ⁸⁰ and R ⁸¹ is the same as the alkyl group ^{exemplified as} the alkyl group in the alkoxy group. Can be mentioned.
Examples of the alkyl group in the halogenated alkyl group as the heteroatom-containing substituent include the same alkyl groups as mentioned for the alkyl group in the alkoxy group. As the halogenated alkyl group, a fluorinated alkyl group is particularly preferred.
Examples of the halogenated alkoxy group as the heteroatom-containing substituent include groups in which some or all of the hydrogen atoms of the alkoxy group have been substituted with the halogen atoms. The halogenated alkoxy group is preferably a fluorinated alkoxy group.
Examples of the hydroxyalkyl group as the heteroatom-containing substituent include groups in which at least one hydrogen atom of the alkyl group mentioned as the alkyl group in the alkoxy group is substituted with a hydroxyl group. 1-3 are preferable and, as for the number of the hydroxyl groups which a hydroxyalkyl group has, 1 is the most preferable.

Examples of the aliphatic hydrocarbon group include a linear or branched saturated hydrocarbon group, a linear or branched monovalent unsaturated hydrocarbon group, or a cyclic aliphatic hydrocarbon group (aliphatic ring). Formula group) is preferred.
The linear saturated hydrocarbon group (alkyl group) preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group and the like.
The branched saturated hydrocarbon group (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 include 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.
As an unsaturated hydrocarbon group, it is preferable that carbon number is 2-10, 2-5 are preferable, 2-4 are preferable, and 3 is especially preferable. Examples of the linear monovalent unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched monovalent unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group. As the unsaturated hydrocarbon group, a propenyl group is particularly preferable.

The aliphatic cyclic group may be a monocyclic group or a polycyclic group. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12.
Specifically, for example, a group in which one or more hydrogen atoms are removed from a monocycloalkane; a group in which one or more hydrogen atoms are removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
When the aliphatic cyclic group does not contain a substituent containing a hetero atom in the ring structure, the aliphatic cyclic group is preferably a polycyclic group, and has one or more hydrogen atoms from the polycycloalkane. Excluded groups are preferred, and most preferred are groups in which one or more hydrogen atoms have been removed from adamantane.
When the aliphatic cyclic group includes a substituent containing a hetero atom in the ring structure, examples of the substituent containing a hetero atom include —O—, —C (═O) —O—, —S—. , —S (═O) ₂ — and —S (═O) ₂ —O— are preferable. Specific examples of the aliphatic cyclic group include groups represented by the following formulas (L1) to (L5) and (S1) to (S4).

［式中、Ｑ”は、酸素原子もしくは硫黄原子を含んでいてもよいアルキレン基、酸素原子または硫黄原子であり、ｍは０または１の整数である。］

[Wherein Q ″ is an alkylene group, an oxygen atom or a sulfur atom which may contain an oxygen atom or a sulfur atom, and m is an integer of 0 or 1.]

In the formula, the alkylene group in Q ″ is preferably linear or branched, and preferably has 1 to 5 carbon atoms. Specifically, a methylene group [—CH ₂ —]; —CH ( _{CH 3) -, - CH (} CH 2 CH 3) -, - C (CH 3) 2 -, - C (CH 3) (CH 2 CH 3) -, - C (CH 3) (CH 2 CH 2 CH ₃ )-, an alkylmethylene group such as —C (CH ₂ CH ₃ ) ₂ —; an 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 An alkyltetramethylene group such as CH ₂ —, a pentamethylene group [—CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ —], etc. Among these, a methylene group or an alkylmethylene group is preferable, and a methylene group, —CH (CH ₃ ) — or —C (CH ₃ ) ₂ — is particularly preferred.
The alkylene group may contain an oxygen atom (—O—) or a sulfur atom (—S—). Specific examples thereof include groups in which —O— or —S— is interposed between the terminal or carbon atoms of the alkylene group. For example, —O—R ⁹⁴ —, —S—R ⁹⁵ —, —R ⁹⁶ — O-R ^{<97 >} -, -R < ^{98 >} -S-R ^<99> -etc. are mentioned. Here, R ^{94 to} R ⁹⁹ are each independently an alkylene group. Examples of the alkylene group include the same alkylene groups as those described above for Q ″. Among them, —O—CH ₂ —, —CH ₂ —O—CH ₂ —, —S—CH ₂ — , —CH ₂ —S—CH ₂ — and the like are preferable.

In these aliphatic cyclic groups, some or all of the hydrogen atoms may be substituted with substituents. Examples of the substituent include an alkyl group, a halogen atom, an alkoxy group, a hydroxyl group, —C (═O) —R ⁸⁰ [R ⁸⁰ is an alkyl group. ], -COOR ⁸¹ [R ⁸¹ is a hydrogen atom or an alkyl group. ], Halogenated alkyl groups, halogenated alkoxy groups, amino groups, amide groups, nitro groups, oxygen atoms (= O), sulfur atoms, sulfonyl groups (SO ₂ ) and the like.
Examples of the alkyl group as the substituent include the same alkyl groups as those described above for the alkoxy group as the heteroatom-containing substituent.
As the alkyl group, an alkyl group having 1 to 6 carbon atoms is particularly preferable. The alkyl group is preferably linear or branched, and specifically includes a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, Examples include pentyl group, isopentyl group, neopentyl group, hexyl group and the like. Among these, a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable.
As the halogen atom, alkoxy group, —C (═O) —R ⁸⁰ , —COOR ⁸¹ , halogenated alkyl group, and halogenated alkoxy group as the substituent, a hydrogen atom constituting the aliphatic hydrocarbon group, respectively. The same thing as the thing quoted as the hetero atom containing substituent which may substitute a part or all of is mentioned.
Among the above, the substituent for substituting the hydrogen atom of the aliphatic cyclic group is preferably an alkyl group, an oxygen atom (= O), or a hydroxyl group.
The number of substituents possessed by the aliphatic cyclic group may be one or two or more. When having a plurality of substituents, the plurality of substituents may be the same or different.

X is preferably a cyclic group which may have a substituent. The cyclic group may be an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a substituent. It is preferably an aliphatic cyclic group that may be used.
The aromatic hydrocarbon group is preferably a naphthyl group which may have a substituent or a phenyl group which may have a substituent.
As the aliphatic cyclic group which may have a substituent, a polycyclic aliphatic cyclic group which may have a substituent is preferable. Examples of the polycyclic aliphatic cyclic group include groups obtained by removing one or more hydrogen atoms from the polycycloalkane, and groups represented by the above (L2) to (L5) and (S3) to (S4). Etc. are preferred.

In the present invention, ^{R 4} ", ^{X-Q 1} - as a substituent preferably has the case, ^{R 4."} The, ^{X-Q 1} -Y 1 - in the Formula, ^{Q 1} and X are the Y ¹ is an optionally substituted alkylene group having 1 to 4 carbon atoms or an optionally substituted fluorinated alkylene group having 1 to 4 carbon atoms. ] Is preferable.
In the group represented by XQ ¹ -Y ^1- , the alkylene group for Y ¹ includes the same alkylene groups as those described above for Q ¹ having 1 to 4 carbon atoms.
Examples of the fluorinated alkylene group include groups in which part or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms.
As Y ^1, _{specifically, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF (CF 2 CF 3) -, _{-C (CF 3) 2 -,} - CF 2 CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF ₃ ) —, —C (CF ₃ ) ₂ CF ₂ —, —CF (CF ₂ CF ₃ ) CF ₂ —, —CF (CF ₂ CF ₂ CF ₃ ) —, —C (CF ₃ ) (CF _{2 CF 3) -; - CHF} -, - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -, - CH (CF 3) CH 2 -, - CH (CF 2 _{CF 3) -, - C (} CH 3) (CF 3) -, - CH 2 CH 2 CH 2 CF 2 -, - C H ₂ CH ₂ CF ₂ CF ₂ —, —CH (CF ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CF ₃ ) CH ₂ —, —CH (CF ₃ ) CH (CF ₃ ) —, —C ( _{CF 3) 2 CH 2 -;} - CH 2 -, - CH 2 CH 2 -, - CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 -, - CH (CH 2 CH 3) -, - _{C (CH 3) 2 -,} - CH 2 CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 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 -, - CH (CH 2 CH 2 CH 3) -, - C (CH 3) (CH 2 CH ₃ ) — and the like.

Y ¹ is preferably a fluorinated alkylene group, and particularly preferably a fluorinated alkylene group in which the carbon atom bonded to the adjacent sulfur atom is fluorinated. Examples of such fluorinated alkylene _{group, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF 2 CF 2 CF 2 CF 2 _{-, - CF (CF 3)} CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF 3) -, - C (CF 3) 2 CF 2 -, _{-CF (CF 2 CF 3) CF} 2 -; - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -; - CH 2 CH 2 CH 2 CF 2 -, - CH ₂ CH ₂ CF ₂ CF ₂ —, —CH ₂ CF ₂ CF ₂ CF ₂ — and the like can be mentioned.
Of _{these, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, or _CH 2 _CF 2 CF ₂ - is _{preferable, -CF 2 -, - CF 2} CF 2 - or -CF ₂ CF ₂ CF ₂ - is more preferable, -CF ₂ - is particularly preferred.

The alkylene group or fluorinated alkylene group may have a substituent. An alkylene group or a fluorinated alkylene group has a “substituent” means that part or all of the hydrogen atom or fluorine atom in the alkylene group or fluorinated alkylene group is substituted with an atom or group other than a hydrogen atom and a fluorine atom. Means that
Examples of the substituent that the alkylene group or fluorinated alkylene group may have include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a hydroxyl group.

In formula (b-2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group. At least one of R ⁵ ″ to R ⁶ ″ represents an aryl group. It is preferable that all of R ⁵ ″ to R ⁶ ″ are aryl groups.
As the aryl group for R ⁵ ″ to R ⁶ ″, the same as the aryl groups for R ¹ ″ to R ³ ″ can be used.
Examples of the alkyl group for R ⁵ ″ to R ⁶ ″ include the same as the alkyl group for R ¹ ″ to R ³ ″.
Among these, it is most preferable that all of R ⁵ ″ to R ⁶ ″ are phenyl groups.
"As ^{R 4} in the formula (b-1)" ^{R 4} in the In the formula (b-2) include the same as.

Specific examples of the onium salt acid generators represented by formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate; bis (4-tert-butylphenyl) iodonium. Trifluoromethane sulfonate or nonafluorobutane sulfonate; triphenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; tri (4-methylphenyl) sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its Nonafluorobutanesulfonate; dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, its heptaful Lopropane sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of monophenyldimethylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of diphenyl monomethylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate (4-methylphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; (4-methoxyphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; Trifluoromethanesulfonate of tri (4-tert-butyl) phenylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutanesulfonate; trifluoromethanesulfonate of diphenyl (1- (4-methoxy) naphthyl) sulfonium, its heptafluoropropane Sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of di (1-naphthyl) phenylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1-phenyltetrahydrothiophenium trifluoromethane sulfonate, its heptafluoropropane sulfonate Or nonafluorobutanesulfonate thereof; 1- (4-methylphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1- (4-ethoxynaphthalene-1- Yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonaflu 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1-phenyltetrahydrothiopyranium trifluoromethanesulfonate , Its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (4-hydroxyphenyl) tetrahydrothiopyranium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl -4-Hydroxyphenyl) tetrahydrothiopyranium trifluoromethanesulfonate, its heptafluoropropanes Honeto or nonafluorobutanesulfonate; 1- (4-methylphenyl) trifluoromethanesulfonate tetrahydrothiophenium Pila chloride, heptafluoropropane sulfonate or its nonafluorobutane sulfonate, and the like.
In addition, the anion part of these onium salts is substituted with methanesulfonate, n-propanesulfonate, n-butanesulfonate, n-octanesulfonate, 1-adamantanesulfonate, 2-norbornanesulfonate, d-camphor-10-sulfonate, etc. An onium salt substituted with an aromatic sulfonate such as benzene sulfonate, perfluorobenzene sulfonate, p-toluene sulfonate, or the like may be used.
Moreover, the onium salt which replaced the anion part of these onium salts by the anion part represented by either of following formula (b1)-(b8) can also be used.

［式中、ｐは１〜３の整数であり、ｖ０は０〜３の整数であり、ｑ１〜ｑ２はそれぞれ独立に１〜５の整数であり、ｑ３は１〜１２の整数であり、ｒ１〜ｒ２はそれぞれ独立に０〜３の整数であり、ｇは１〜２０の整数であり、ｔ３は１〜３の整数であり、Ｒ^７は置換基であり、Ｒ^８は水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基である。］

[Wherein, p is an integer of 1 to 3, v0 is an integer of 0 to 3, q1 to q2 are each independently an integer of 1 to 5, q3 is an integer of 1 to 12, and r1 ~r2 are each independently an integer of 0 to 3, g is an integer of 1 to 20, t3 is an integer from 1 to 3, ^{R 7} is a substituent, ^{R 8} is a hydrogen atom, the number of carbon atoms It is a 1-5 alkyl group or a C1-C5 halogenated alkyl group. ]

［式中、ｐ、Ｒ^７、Ｑ”はそれぞれ前記と同じであり、ｎ１〜ｎ５はそれぞれ独立に０または１であり、ｖ１〜ｖ５はそれぞれ独立に０〜３の整数であり、ｗ１〜ｗ５はそれぞれ独立に０〜３の整数である。］

[Wherein, p, R ⁷ and Q ″ are the same as defined above, n1 to n5 are each independently 0 or 1, v1 to v5 are each independently an integer of 0 to 3, w1 to w5 Are each independently an integer of 0 to 3.]

Examples of the substituent for R ⁷ include an alkyl group and a heteroatom-containing substituent. Examples of the alkyl group include those similar to the alkyl group mentioned as the substituent that the aromatic hydrocarbon group may have in the description of X. In addition, the heteroatom-containing substituent is the same as the heteroatom-containing substituent that may substitute part or all of the hydrogen atoms constituting the aliphatic hydrocarbon group in the description of X. Is mentioned.
Code (r1 and r2, w1 to w5) attached to R ⁷ when is an integer of 2 or more, a plurality of the ^{R 7} groups may be the same, respectively, may be different.
Examples of the alkyl group and halogenated alkyl group for R ⁸ include the same alkyl groups and halogenated alkyl groups as those described above for R.
r1 to r2 and w1 to w5 are each preferably an integer of 0 to 2, and more preferably 0 or 1.
v0 to v5 are preferably 0 to 2, and most preferably 0 or 1.
t3 is preferably 1 or 2, and most preferably 1.
q3 is preferably 1 to 5, more preferably 1 to 3, and most preferably 1.

  Moreover, as an onium salt type | system | group acid generator, in the said general formula (b-1) or (b-2), an anion part is represented by the following general formula (b-3) or (b-4). An onium salt-based acid generator replaced with can also be used (the cation moiety is the same as (b-1) or (b-2)).

［式中、Ｘ”は、少なくとも１つの水素原子がフッ素原子で置換された炭素数２〜６のアルキレン基を表し；Ｙ”、Ｚ”は、それぞれ独立に、少なくとも１つの水素原子がフッ素原子で置換された炭素数１〜１０のアルキル基を表す。］

[Wherein X ″ represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom; Y ″ and Z ″ each independently represent at least one hydrogen atom as a fluorine atom; Represents an alkyl group having 1 to 10 carbon atoms and substituted with

X ″ is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms, Most preferably, it has 3 carbon atoms.
Y ″ and Z ″ are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, preferably Has 1 to 7 carbon atoms, more preferably 1 to 3 carbon atoms.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, as the number of hydrogen atoms substituted with fluorine atoms increases, the strength of the acid increases, and high-energy light or electron beam of 200 nm or less The ratio of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all. Are a perfluoroalkylene group or a perfluoroalkyl group in which a hydrogen atom is substituted with a fluorine atom.

In the general formula (b-1) or (b-2), the anion moiety (R ⁴ ″ SO ₃ ⁻ ) is R ⁷ ″ -COO ⁻ [wherein R ⁷ ″ is an alkyl group or a fluorinated alkyl group. An onium salt-based acid generator replaced with a cation group can be used (the cation moiety is the same as (b-1) or (b-2)).
Examples of R ⁷ ″ include the same as R ⁴ ″ described above.
Specific examples of the “R ⁷ ″ —COO ⁻ ” include trifluoroacetate ion, acetate ion, 1-adamantanecarboxylate ion and the like.

  In this specification, the oxime sulfonate acid generator is a compound having at least one group represented by the following general formula (B-1), and has a property of generating an acid upon irradiation with radiation. is there. Such oxime sulfonate-based acid generators are frequently used for chemically amplified resist compositions, and can be arbitrarily selected and used.

（式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。）

(In formula (B-1), R ³¹ and R ³² each independently represents an organic group.)

The organic groups of R ³¹ and R ³² are groups containing carbon atoms, and atoms other than carbon atoms (for example, hydrogen atoms, oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms (fluorine atoms, chlorine atoms, etc.), etc.) You may have.
As the organic group for R ^31, a linear, branched, or cyclic alkyl group or aryl group is preferable. These alkyl groups and aryl groups may have a substituent. There is no restriction | limiting in particular as this substituent, For example, a fluorine atom, a C1-C6 linear, branched or cyclic alkyl group etc. are mentioned. Here, “having a substituent” means that part or all of the hydrogen atoms of the alkyl group or aryl group are substituted with a substituent.
As an alkyl group, C1-C20 is preferable, C1-C10 is more preferable, C1-C8 is more preferable, C1-C6 is especially preferable, and C1-C4 is the most preferable. As the alkyl group, a partially or completely halogenated alkyl group (hereinafter sometimes referred to as a halogenated alkyl group) is particularly preferable. The partially halogenated alkyl group means an alkyl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated alkyl group means that all of the hydrogen atoms are halogen atoms. Means an alkyl group substituted with 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. That is, the halogenated alkyl group is preferably a fluorinated alkyl group.
The aryl group preferably has 4 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms. As the aryl group, a partially or completely halogenated aryl group is particularly preferable. The partially halogenated aryl group means an aryl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated aryl group means that all of the hydrogen atoms are halogen atoms. Means an aryl group substituted with.
R ³¹ is particularly preferably an alkyl group having 1 to 4 carbon atoms having no substituent or a fluorinated alkyl group having 1 to 4 carbon atoms.
As the organic group for R ^32, a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^32, the same alkyl groups and aryl groups as those described above for R ³¹ can be used.
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

  More preferable examples of the oxime sulfonate-based acid generator include compounds represented by the following general formula (B-2) or (B-3).

［式（Ｂ−２）中、Ｒ^３３は、シアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３４はアリール基である。Ｒ^３５は置換基を有さないアルキル基またはハロゲン化アルキル基である。］

[In Formula (B-2), R ³³ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁴ is an aryl group. R ³⁵ represents an alkyl group having no substituent or a halogenated alkyl group. ]

［式（Ｂ−３）中、Ｒ^３６はシアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３７は２または３価の芳香族炭化水素基である。Ｒ^３８は置換基を有さないアルキル基またはハロゲン化アルキル基である。ｐ”は２または３である。］

[In Formula (B-3), R ³⁶ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁷ is a divalent or trivalent aromatic hydrocarbon group. ^R38 is an alkyl group having no substituent or a halogenated alkyl group. p ″ is 2 or 3.]

In the general formula (B-2), the alkyl group or halogenated alkyl group having no substituent for R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably carbon atoms. Numbers 1 to 6 are most preferable.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred.
As the aryl group of R ³⁴ , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, or a phenanthryl group. And heteroaryl groups in which some of the carbon atoms constituting the ring of these groups are substituted with heteroatoms such as oxygen, sulfur, and nitrogen atoms. Among these, a fluorenyl group is preferable.
The aryl group of R ³⁴ may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.
The alkyl group or halogenated alkyl group having no substituent for R ³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³⁵ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³⁵ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred is the strength of the acid generated. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

In the general formula (B-3), the alkyl group or halogenated alkyl group having no substituent for R ³⁶ is the same as the alkyl group or halogenated alkyl group having no substituent for R ^33. Is mentioned.
Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁷ include groups obtained by further removing one or two hydrogen atoms from the aryl group for R ³⁴ .
Examples of the alkyl group or halogenated alkyl group having no substituent of R ³⁸ include the same alkyl groups or halogenated alkyl groups as those having no substituent of R ³⁵ .
p ″ is preferably 2.

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Further, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), WO2004 / 074242A2 (pages 65 to 85). The oxime sulfonate acid generators disclosed in Examples 1 to 40) of No. 1 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfonyldiazomethanes include bis (isopropylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, Examples include bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.
Further, diazomethane acid generators disclosed in JP-A-11-035551, JP-A-11-035552, and JP-A-11-035573 can also be suitably used.
Examples of poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane and 1,4-bis (phenylsulfonyldiazo) disclosed in JP-A-11-322707. Methylsulfonyl) butane, 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane, 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane, 1,3 -Bis (cyclohexylsulfonyldiazomethylsulfonyl) propane, 1,6-bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (cyclohexylsulfonyldiazomethylsulfonyl) decane, etc. Door can be.

(B) As a component, these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.
In the present invention, it is preferable to use an onium salt acid generator having a fluorinated alkyl sulfonate ion as an anion as the component (B).
0.5-50 mass parts is preferable with respect to 100 mass parts of (A) component, and, as for content of (B) component in the resist composition of this invention, 1-40 mass parts is more preferable. By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

<Optional component>
The positive resist composition of the present invention may further contain a nitrogen-containing organic compound (D) (hereinafter referred to as “component (D)”) as an optional component.
The component (D) is not particularly limited as long as it acts as an acid diffusion controller, that is, a quencher that traps the acid generated from the component (B) by exposure, and a wide variety of components have already been proposed. Therefore, any known one may be used.
As the component (D), a low molecular compound (non-polymer) is usually used. Examples of the component (D) include amines such as aliphatic amines and aromatic amines, and aliphatic amines are preferable, and secondary aliphatic amines and tertiary aliphatic amines are particularly preferable. Here, the aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 20 carbon atoms.
Examples of the aliphatic amine include an amine (alkylamine or alkyl alcohol amine) or a cyclic amine in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 20 or less carbon atoms. .
Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di- -Dialkylamines such as n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine , Trialkylamines such as tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine, Li isopropanolamine, di -n- octanol amine, tri -n- octanol amine, stearyl diethanolamine, alkyl alcohol amines such as lauryl diethanolamine. Among these, trialkylamine and / or alkyl alcohol amine are preferable.
Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be monocyclic (aliphatic monocyclic amine) or polycyclic (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
As the aliphatic polycyclic amine, those having 6 to 10 carbon atoms are preferable. Specifically, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5. 4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, and the like.
Other aliphatic amines include tris (2-methoxymethoxyethyl) amine, tris {2- (2-methoxyethoxy) ethyl} amine, tris {2- (2-methoxyethoxymethoxy) ethyl} amine, tris {2 -(1-methoxyethoxy) ethyl} amine, tris {2- (1-ethoxyethoxy) ethyl} amine, tris {2- (1-ethoxypropoxy) ethyl} amine, tris [2- {2- (2-hydroxy Ethoxy) ethoxy} ethylamine and the like.
Examples of the aromatic amine include aniline, pyridine, 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, diphenylamine, triphenylamine, tribenzylamine, and the like.
These may be used alone or in combination of two or more.
(D) component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component. By setting the content in the above range, the resist pattern shape, the stability over time, and the like are improved.

The positive resist composition of the present invention includes, as optional components, organic carboxylic acids, phosphorus oxoacids and derivatives thereof for the purpose of preventing sensitivity deterioration, improving the resist pattern shape, retention stability over time, etc. At least one compound (E) selected from the group consisting of (hereinafter referred to as component (E)) can be contained.
As the organic carboxylic acid, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Examples of phosphorus oxo acids and derivatives thereof 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 oxo acid is substituted with a hydrocarbon group, and the hydrocarbon group includes an alkyl group having 1 to 5 carbon atoms and 6 to 6 carbon atoms. 15 aryl groups and the like.
Examples of phosphoric acid derivatives include phosphoric acid esters such as di-n-butyl phosphate and diphenyl phosphate.
Examples of phosphonic acid derivatives include phosphonic acid esters such as phosphonic acid dimethyl ester, phosphonic acid-di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, and phosphonic acid dibenzyl ester.
Examples of the phosphinic acid derivatives include phosphinic acid esters such as phenylphosphinic acid.
(E) A component may be used individually by 1 type and may use 2 or more types together.
(E) A component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

  The positive resist composition of the present invention further contains miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving coating properties, dissolution inhibitors, Plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like can be added and contained as appropriate.

The positive resist composition of the present invention can be produced by dissolving the material in an organic solvent (hereinafter sometimes referred to as (S) component).
As the component (S), any component can be used as long as it can dissolve each component to be used to form a uniform solution. Conventionally, any one of known solvents for chemically amplified resists can be used. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone;
Ketones such as acetone, methyl ethyl ketone, cycloheptanone, cyclohexanone (CH), methyl-n-pentyl ketone, methyl isopentyl ketone, 2-heptanone;
Polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol;
Compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, monomethyl ether, monoethyl ether, monopropyl of the polyhydric alcohols or the compound having an ester bond Derivatives of polyhydric alcohols such as ethers, monoalkyl ethers such as monobutyl ether or compounds having an ether bond such as monophenyl ether [in these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME) Is preferred];
Cyclic ethers such as dioxane and esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate;
Aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. be able to.
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Among these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and EL are preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is also preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to be within the range.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 3.
In addition, as the component (S), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.
The amount of component (S) used is not particularly limited, but is a concentration that can be applied to a substrate or the like, and is appropriately set according to the coating film thickness. In general, the solid content concentration of the resist composition is 1 -20% by mass, preferably 2-15% by mass.

According to the positive resist composition of the present invention, the lithography characteristics in optical lithography such as KrF excimer laser and ArF excimer laser, and various lithography such as EB lithography and EUV lithography are good, and sensitivity, exposure margin (EL), etc. The lithographic properties are good. Further, there is little film loss when forming a resist pattern.
EL is a range of exposure that can form a resist pattern with a dimension within which the deviation from the target dimension is within a predetermined range when the exposure is changed, that is, an exposure that provides a resist pattern that is faithful to the mask pattern. The larger the EL margin value, the smaller the change amount of the pattern size accompanying the change in the exposure amount, and the better the process margin.
Furthermore, according to the positive resist composition of the present invention, a resist pattern having a small LWR (line width roughness) can be formed. LWR is a phenomenon in which when a resist pattern is formed using a resist composition, the pattern surface is roughened (roughness) and the line width of the line pattern becomes non-uniform. If the LWR is large, the formation of fine semiconductor elements and the like may be adversely affected. Therefore, the improvement becomes more important as the pattern becomes finer.
Since lithography using EB or EUV is aimed at forming a fine pattern of several tens of nanometers, the effect of suppressing film loss and the effect of improving LWR are extremely effective in performing lithography using EB or EUV.
The reason why the above effect is obtained is not clear, but the reason is that the structural unit (a0) has a bulky naphthalene ring and a relatively easily dissociable acid-dissociable, dissolution-inhibiting group. It is thought to be due to interaction. Moreover, since the structural unit (a0) is bulky, film loss during development is suppressed. As a result, it is considered that the surface roughness is good and therefore the LWR is also improved.
The naphthalene ring included in the structural unit (a0) has a larger π conjugation than the benzene ring, and thus is considered to have high efficiency in generating secondary electrons by irradiation with an electron beam or EUV.
The structural unit (a0) has a bulky and bulky structure as compared with the conventional acetal type acid dissociable, dissolution inhibiting group. Therefore, the positive resist composition of the present invention is difficult to vaporize after the acid dissociable, dissolution inhibiting group is dissociated, can suppress the generation of outgas at the time of forming a resist pattern, and reduce contamination of the exposure apparatus. Furthermore, compared with the conventional 1-ethoxyethyl group or t-butoxycarbonyl group, the effect of inhibiting dissolution in the developer is large, the pattern film is reduced, and the pattern shape is good, and the effect of reducing LWR is expected. Is done.

≪Resist pattern formation method≫
The resist pattern forming method of the present invention comprises a step of forming a resist film on a support using the positive resist composition of the present invention, a step of exposing the resist film, and developing the resist film to form a resist. Forming a pattern.
The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, first, the positive resist composition of the present invention is applied onto a support with a spinner or the like, and pre-baked (post-apply bake (PAB)) for 40 to 120 seconds under a temperature condition of 80 to 150 ° C., preferably A resist film is formed by applying for 60 to 90 seconds. For example, using an exposure apparatus such as an ArF exposure apparatus, an electron beam drawing apparatus, or an EUV exposure apparatus, exposure through a mask (mask pattern) on which a predetermined pattern is formed, or direct electron beam without using a mask pattern After selectively exposing by drawing by irradiation or the like, PEB (post-exposure heating) is applied for 40 to 120 seconds, preferably 60 to 90 seconds under a temperature condition of 80 to 150 ° C. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide (TMAH), preferably rinsed with pure water and dried. In some cases, a baking process (post-bake) may be performed after the development process.
In this way, a resist pattern faithful to the mask pattern can be obtained.

The support is not particularly limited, and a conventionally known one can be used, and examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
Further, the support may be a substrate in which an inorganic and / or organic film is provided on the above-described substrate. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include organic films such as an organic antireflection film (organic BARC) and a lower organic film in a multilayer resist method.
Here, the multilayer resist method is a method in which at least one organic film (lower organic film) and at least one resist film (upper resist film) are provided on a substrate, and the resist pattern formed on the upper resist film is used as a mask. This is a method of patterning a lower organic film, and it is said that a pattern with a high aspect ratio can be formed. That is, according to the multilayer resist method, the required thickness can be secured by the lower organic film, so that the resist film can be thinned and a fine pattern with a high aspect ratio can be formed.
In the multilayer resist method, basically, 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 multilayer structure of three or more layers provided with a metal thin film or the like (three-layer resist method).

The wavelength used for exposure is not particularly limited, and 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. Can be done using radiation. The resist composition is highly useful for KrF excimer laser, ArF excimer laser, EB or EUV, and is more effective for KrF excimer laser, EB or EUV.

The exposure method of the resist film may be normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or may be immersion exposure (Liquid Immersion Lithography).
In immersion exposure, the space between the resist film and the lens at the lowest position of the exposure apparatus is previously filled with a solvent (immersion medium) having a refractive index larger than 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 larger than the refractive index of air and smaller than the refractive index of the resist film to be exposed is preferable. The refractive index of such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.
Specific examples of the fluorine-based inert liquid include 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, and 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 in the above range since 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.
More specifically, examples of the perfluoroalkyl ether compound include perfluoro (2-butyl-tetrahydrofuran) (boiling point: 102 ° C.). Examples of the perfluoroalkylamine compound include perfluorotributylamine ( Boiling point of 174 ° C.).
As the immersion medium, water is preferably used from the viewpoints of cost, safety, environmental problems, versatility, and the like.

≪Polymer compound≫
The polymer compound according to the third aspect of the present invention has a structural unit (a0) represented by the following general formula (a0).

［式中、Ｒは、水素原子、炭素数１〜５のアルキル基、または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^１、Ｒ^２はそれぞれ独立に、メチル基、エチル基またはイソプロピル基であり、Ｒ^３、Ｒ^４はそれぞれ独立に、ハロゲン原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、ｐは０〜３の整数であり、ｑは０〜４の整数である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and R ¹ and R ² are each independently a methyl group, an ethyl group, or isopropyl. R ³ and R ⁴ are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, p is an integer of 0 to 3, q Is an integer from 0 to 4. ]

  The description of the polymer compound of the present invention is the same as the description of the polymer compound (A1) in the positive resist composition of the present invention.

The polymer compound of the present invention is a novel compound not conventionally known.
A resist composition using the polymer compound is useful as a resin composition of a resist composition because it has excellent resolution especially in forming a fine resist pattern.

≪Compound≫
The compound according to the fourth aspect of the present invention is represented by the following general formula (M0).

［式中、Ｒは、水素原子、炭素数１〜５のアルキル基、または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^１、Ｒ^２はそれぞれ独立に、メチル基、エチル基またはイソプロピル基であり、Ｒ^３、Ｒ^４はそれぞれ独立に、ハロゲン原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、ｐは０〜３の整数であり、ｑは０〜４の整数である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and R ¹ and R ² are each independently a methyl group, an ethyl group, or isopropyl. R ³ and R ⁴ are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, p is an integer of 0 to 3, q Is an integer from 0 to 4. ]

In the formula (M0), R and R ^{1 to} R ⁴ are the same as the formula (a0).

The manufacturing method of the compound of this invention is not specifically limited, It can manufacture using a well-known method.
For example, in a solvent such as tetrahydrofuran, toluene, methylene chloride or the like, the compound represented by the general formula (q2) (for example, 1-hydroxy-1-methyl-1-naphthylethyl derivative) may be converted to triethylamine or pyridine as necessary. In the presence of a base such as 4-dimethylaminopyridine, a (meth) acrylic acid halide such as (meth) acrylic acid chloride or a (meth) acrylic acid reactive derivative such as (meth) acrylic anhydride is reacted. Thus, the monomer represented by the general formula (M0) can be obtained.
In addition, a compound represented by the general formula (q2) is reacted with an ester of (meth) acrylic acid such as methyl (meth) acrylate in the presence of a transesterification catalyst such as titanium isopropoxide in a solvent. Also good. In addition, the compound represented by the general formula (q2) can also be obtained by reacting with (meth) acrylic acid in the presence of a strong acid such as hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, etc.
The monomer represented by the general formula (M0) thus obtained is separated by a separating means such as filtration, concentration, distillation, extraction, crystallization, recrystallization, column chromatography, or a combination thereof. Can be separated and purified.

［式（ｑ２）中、Ｒ^１〜Ｒ^４は、式（ａ０）中のＲ^１〜Ｒ^４と同様である。］

Wherein ^(q2), R 1 ~R ⁴ is the same as ^R 1 to R ⁴ in the formula (a0). ]

The structure of the obtained compound is as follows: ¹ H-nuclear magnetic resonance (NMR) spectrum method, ¹³ C-NMR spectrum method, ¹⁹ F-NMR spectrum method, infrared absorption (IR) spectrum method, mass spectrometry (MS) method, element It can be confirmed by a general organic analysis method such as analysis method or X-ray crystal diffraction method.

The compound of the present invention is a novel compound that has not been known so far.
Moreover, the compound of this invention is a monomer which provides the structural unit (a0) which comprises the high molecular compound of the said invention.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.
In this example, the unit represented by the chemical formula (1) is referred to as “compound (1)”, and the same applies to compounds represented by other formulas.
In the analysis by NMR, the internal standard of ¹ H-NMR and ¹³ C-NMR is tetramethylsilane (TMS).

[Monomer Synthesis Example 1: Synthesis of Compound (1)]
20 g (0.107 mol) of 1-hydroxy-1-methyl-1-naphthylethane and 16.9 g (0.25 mol) of pyridine were stirred in tetrahydrofuran (THF) (300 ml), and methacrylic acid chloride 25. 8 g (0.215 mol) was added dropwise. After stirring at room temperature for 10 hours, the product obtained by filtration was separated and purified to obtain compound (1). The instrumental analysis results of the compound were as follows.
¹ H-NMR (400 MHz, CDCl ₃ ): δ (ppm) = 7.8-7.9 (m, 4H, Hd ₁ , Hd ₂ ), 7.53-7.55 (d, 1H, Hd ₁ ) 7.48-7.51 (m, 2H, Hd ₃ ), 6.2 (s, 1H, Ha), 5.6 (s, 1H, Ha), 1.98 (s, 3H, Hb), 1.96 (s, 6H, Hc).

[Monomer Synthesis Example 2: Synthesis of Compound (4)]
In a 500 ml three-necked flask, under a nitrogen atmosphere, 20 g (105.14 mmol) of alcohol (1), 30.23 g (157.71 mmol) of ethyldiisopropylaminocarbodiimide (EDCI) hydrochloride and 0.6 g of dimethylaminopyridine (DMAP) After adding 300 ml of a THF solution of (5 mmol), 16.67 g (115.66 mmol) of the precursor (1) was added under ice cooling (0 ° C.), and the mixture was stirred at room temperature for 12 hours.
After confirming disappearance of the raw material by thin layer chromatography (TLC), 50 ml of water was added to stop the reaction. The reaction solvent was concentrated under reduced pressure, and the organic layer obtained by extraction three times with ethyl acetate was washed with water, saturated sodium bicarbonate and 1N-HClaq in this order. The product obtained by distilling off the solvent under reduced pressure was dried to obtain the desired compound (4).
The instrumental analysis results of the obtained compound were as follows.
¹ H-NMR (400 MHz, CDCl ₃ ): δ (ppm) = 6.22 (s, 1H, H ^a ), 5.70 (s, 1H, H ^b ), 4.71-4.85 (m, 2H, H ^{c, d} ), 4.67 (s, 2H, H ^k ), 3.40-3.60 (m, 2H, H ^{e, f} ), 2.58-2.70 (m, 1H, ^{H g), 2.11-2.21 (m,} 2H, H h), 2.00 (s, 3H, H i), 1.76-2.09 (m, 2H, H j).

[Polymer synthesis example 1]
26.7 g (0.105 mol) of the above compound (1), 40 g (0.246 mol) of 4-acetoxystyrene (compound (2)), 4.25 g (0.018 mol) of V601 (dimethyl azobisisobutyrate) as a polymerization initiator. It was dissolved in PGMEA (114 ml) to obtain a monomer mixed PGMEA solution. A flask equipped with a nitrogen inlet, a stirrer, a condenser and a thermometer was charged with PGMEA (85 ml) under a nitrogen atmosphere, the temperature of the hot water bath was raised to 80 ° C. while stirring, and the monomer mixed PGMEA solution was The solution was dropped into the flask over 6 hours at a constant speed by a dropping device and kept at 80 ° C. for 1 hour. Thereafter, the reaction solution was returned to room temperature. Next, the obtained reaction solution was added dropwise to about 30 times amount of methanol with stirring to obtain a colorless precipitate. The resulting precipitate was filtered off, and the precipitate was washed in about 30 times the amount of methanol used for the monomer used for the polymerization. Then, this precipitate was filtered off and dissolved in THF (200 ml), and then an 80% by mass hydrazine aqueous solution (200 ml) was added dropwise to the solution, followed by stirring at 25 ° C. for 1 hour. After completion of the reaction, the mixture was dropped into a large amount of water to obtain a precipitate. The precipitate was filtered, washed, and dried under reduced pressure at 50 ° C. for about 40 hours to obtain polymer compound 1.
About this high molecular compound 1, the mass mean molecular weight (Mw) of standard polystyrene conversion calculated | required by GPC measurement was 6000, and molecular weight dispersion degree (Mw / Mn) was 3.49. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m = 30.7 / 69. 3.

[Polymer synthesis example 2]
Polymer compound 2 was synthesized in the same manner as in Synthesis Example 1 except that the monomer charge ratio was changed to compound (1) / compound (2) = 40/60 (molar ratio).

（Ｍｗ＝６７００、Ｍｗ／Ｍｎ＝１．９８、共重合組成比：ｌ／ｍ＝４１．７／５８．３（モル比））

(Mw = 6700, Mw / Mn = 1.98, copolymer composition ratio: 1 / m = 41.7 / 58.3 (molar ratio))

[Polymer synthesis examples 3 to 5]
Polymer compounds 3 to 4 were synthesized by a known radical polymerization method by adjusting the monomer charge ratio. In the following reaction formula, MEK is methyl ethyl ketone. Polymer compound 5 was synthesized by the same method as in Polymer Synthesis Example 1 except that the preparation ratio was adjusted using compound (1 ′) instead of compound (1).

（Ｍｗ＝６８００、Ｍｗ／Ｍｎ＝２．００、共重合組成比：ｌ／ｍ／ｎ＝４０．５／２０／３９．５（モル比））

(Mw = 6800, Mw / Mn = 2.00, copolymer composition ratio: 1 / m / n = 40.5 / 20 / 39.5 (molar ratio))

（Ｍｗ＝６０００、Ｍｗ／Ｍｎ＝２．０２、共重合組成比：ｌ／ｍ／ｎ＝４１／２０／３９（モル比））

(Mw = 6000, Mw / Mn = 2.02, copolymer composition ratio: 1 / m / n = 41/20/39 (molar ratio))

（Ｍｗ＝６５００、Ｍｗ／Ｍｎ＝２．２１、共重合組成比：ｌ／ｍ＝３１．６／６８．４（モル比））

(Mw = 6500, Mw / Mn = 2.21, copolymer composition ratio: 1 / m = 31.6 / 68.4 (molar ratio))

[Examples 1 to 12 and Comparative Example 1]
Each component shown in Table 1 was mixed and dissolved to prepare a positive resist composition.

In Table 1, the numerical values in [] indicate the blending amount (parts by mass). Moreover, the symbol in Table 1 shows the following, respectively. The following (A) -6 to (A) -10 were synthesized by the same method as the polymer compound 4 except that the monomer charge ratio was adjusted.
(A) -1: The polymer compound 1.
(A) -2: The polymer compound 2.
(A) -3: The polymer compound 3.
(A) -4: The polymer compound 4.
(A) -5: The polymer compound 5.
(A) -6: In the formula of the polymer compound 4, (Mw = 6800, Mw / Mn = 2.44, copolymer composition ratio: 1 / m / n = 40/20/40 (molar ratio)). Polymer compound 6.
(A) -7: in the formula of the polymer compound 4 (Mw = 4000, Mw / Mn = 1.98, copolymer composition ratio: 1 / m / n = 40/20/40 (molar ratio)). Polymer compound 7.
(A) -8: in the formula of the polymer compound 4 (Mw = 6700, Mw / Mn = 2.28, copolymer composition ratio: 1 / m / n = 50/0/50 (molar ratio)). Polymer compound 8;
(A) -9: in the formula of the polymer compound 4 (Mw = 6700, Mw / Mn = 1.96, copolymer composition ratio: 1 / m / n = 44/12/44 (molar ratio)). Polymer compound 9;
(A) -10: in the formula of the polymer compound 4 (Mw = 6900, Mw / Mn = 1.90, copolymer composition ratio: 1 / m / n = 31/12/57 (molar ratio)). Polymer compound 10.
(B) -1: a compound represented by the following chemical formula (B) -1.
(B) -2: A compound represented by the following chemical formula (B) -2.
(B) -3: A compound represented by the following chemical formula (B) -3.
(D) -1: tri-n-octylamine.
(E) -1: salicylic acid.
(S) -1: PGMEA / PGME = 6/4 (mass ratio) mixed solvent.
(S) -2: Mixed solvent of PGMEA / PGME / CH = 41/36/23 (mass ratio).
(S) -3: γ-butyrolactone.

Using the obtained resist composition, a resist pattern was formed by the following procedure, and the lithography characteristics were evaluated.
[Resist pattern formation] [Sensitivity / Resolution]
The positive resist compositions of Examples 1 to 12 and Comparative Example 1 were uniformly applied to each of 8-inch silicon substrates subjected to hexamethyldisilazane (HMDS) treatment at 90 ° C. for 36 seconds using a spinner. Then, a baking process (PAB) for 60 seconds was performed at the temperature shown in Table 2 to form a resist film (film thickness: 40 nm).
Next, the resist film is drawn (exposed) at an accelerating voltage of 70 keV using an electron beam lithography machine HL-800D (VSB) (manufactured by Hitachi), and baked at 90 ° C. for 60 seconds (PEB). And after developing for 60 seconds at 23 ° C. using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) (trade name: NMD-3, manufactured by Tokyo Ohka Kogyo Co., Ltd.) A line-and-space (LS) pattern was formed by rinsing with water for 15 seconds and performing shake-off drying.
At this time, an exposure amount (Eop; μC / cm ² ) at which a LS pattern having a line width of 100 nm and a pitch of 200 nm was formed at 1: 1 was determined. The results are shown in Table 2.
Further, when the limiting resolution (nm) in the above Eop was determined using a scanning electron microscope S-9220 (manufactured by Hitachi), the limiting resolution was 50 nm in any of Examples 1 to 12 and Comparative Example 1. It was.

[LWR (line width roughness) evaluation]
An LS pattern having a line width of 100 nm and a pitch of 200 nm was formed according to the same procedure as the formation of the resist pattern, with the exposure amount at the time of drawing (exposure) being the Eop.
In this LS pattern having a line width of 100 nm and a pitch of 200 nm, a side length SEM (scanning electron microscope, acceleration voltage 800 V, product name: S-9220, manufactured by Hitachi, Ltd.) was used to change the line width to 400 points in the longitudinal direction of the line Measurement was performed, and a value (3 s) that was three times the standard deviation (s) was obtained from the result, and a value averaged for 3 s at five locations was calculated as a scale indicating LWR. The results are shown in Table 2.
The smaller the value of 3s, the smaller the roughness of the line width, which means that a more uniform width LS pattern was obtained.

[Measurement of dissolution rate (R _min )]
The positive resist composition of each example was uniformly applied onto an 8-inch silicon substrate using a spinner, and treated on a hot plate at 100 ° C. for 60 seconds. This resist film was immersed in a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, and the dissolution rate (film reduction amount / immersion time, R _min , unit: nm / second) was determined. The results are shown in Table 2. It should be _noted that the smaller the value of R _min, the better with less film loss.

  As shown in the results of Table 2, according to the resist compositions of Examples 1 to 4, a fine resist pattern could be formed with good sensitivity. Further, the formed resist pattern had less film loss and a lower LWR than the resist composition of Comparative Example 1. Moreover, also about Examples 5-12 which changed composition, such as (B) component, it has confirmed that there were few film | membrane reductions with the same sensitivity, and LWR was also small.

Claims (11)

A positive resist composition comprising a base component (A) whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator component (B) that generates an acid upon exposure,
The positive resist composition, wherein the substrate component (A) contains a polymer compound (A1) having a structural unit (a0) represented by the following general formula (a0).

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and R ¹ and R ² are each independently a methyl group, an ethyl group, or isopropyl. R ³ and R ⁴ are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, p is an integer of 0 to 3, q Is an integer from 0 to 4. ] The polymer compound (A1) is further a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group, or a structural unit derived from an acrylate ester containing a —SO ₂ — containing cyclic group The positive resist composition according to claim 1, comprising at least one of (a5) and a structural unit (a3) represented by the following general formula (a3).

[Wherein, R is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and Y ¹ is a divalent linking group. ]   The proportion of the structural unit (a0) is 20 to 60 mol% and the proportion of the structural unit (a2) and / or the structural unit (a5) is 0 to 0 with respect to all the structural units constituting the polymer compound (A1). 3. The positive resist composition according to claim 1, wherein 80 mol% and the proportion of the structural unit (a3) is 0 to 80 mol%.   The sum of the ratio of the structural unit (a2) and / or the structural unit (a5) and the ratio of the structural unit (a3) to the total structural units constituting the polymer compound (A1) is 40 to 80 mol. The positive resist composition according to claim 2 or 3, wherein the positive resist composition is%.   Furthermore, the positive resist composition as described in any one of Claims 1-4 containing a nitrogen-containing organic compound component (D).   A step of forming a resist film on a support using the positive resist composition according to claim 1, a step of exposing the resist film, and an alkali developing of the resist film to form a resist A resist pattern forming method including a step of forming a pattern. A polymer compound comprising a structural unit (a0) represented by the following general formula (a0).

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and R ¹ and R ² are each independently a methyl group, an ethyl group, or isopropyl. R ³ and R ⁴ are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, p is an integer of 0 to 3, q Is an integer from 0 to 4. ] Furthermore, the structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group, the structural unit (a5) derived from an acrylate ester containing a —SO ₂ — containing cyclic group, and the following general formula ( The high molecular compound of Claim 7 which has at least any one of the structural unit (a3) represented by a3).

[Wherein, R is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and Y ¹ is a divalent linking group. ]   The proportion of the structural unit (a0) is 20 to 60 mol%, the proportion of the structural unit (a2) and / or the structural unit (a5) is 0 to 80 mol%, and the structural unit (a3). The polymer compound according to claim 7 or 8, wherein the ratio of is from 0 to 80 mol%.   The sum of the ratio of the structural unit (a2) and / or the structural unit (a5) and the ratio of the structural unit (a3) to all structural units is 40 to 80 mol%. High molecular compound. The compound represented by the following general formula (M0).

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and R ¹ and R ² are each independently a methyl group, an ethyl group, or isopropyl. R ³ and R ⁴ are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, p is an integer of 0 to 3, q Is an integer from 0 to 4. ]