JP5162423B2 - Positive resist composition and resist pattern forming method - Google Patents

Description

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

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, the resist film is selectively exposed with radiation such as light or an electron beam, and subjected to a development process, whereby the resist A step of forming a resist pattern having a predetermined shape on the film is performed. 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 wavelength of an exposure light source is generally shortened. 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. In addition, studies have been made on F ₂ excimer lasers, electron beams, EUV (extreme ultraviolet rays), X-rays, and the like having shorter wavelengths than these excimer lasers.

Resist materials are required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing patterns with fine dimensions. As a resist material that satisfies such requirements, a chemically amplified resist containing a base resin whose solubility in an alkaline developer is changed by the action of an acid and an acid generator that generates an acid upon exposure is used. For example, a positive chemically amplified resist contains, as a base resin, a resin that increases solubility in an alkaline developer by the action of an acid and an acid generator. When the acid is generated, the exposed portion becomes soluble in the alkaline developer.
At present, as a chemically amplified positive resist, a resin in which a hydrophilic group is protected by a group (acid dissociable, dissolution inhibiting group) that is dissociated by the action of an acid generated from an acid generator is usually used. , A resin in which a part of hydroxyl groups of a polyhydroxystyrene resin is protected with an acid dissociable, dissolution inhibiting group, a copolymer of hydroxystyrene and a (meth) acrylic acid ester having an acid dissociable, dissolution inhibiting group (for example, a patent) Documents 1 and 2 and Non-Patent Document 1), acrylic resins having an acid dissociable, dissolution inhibiting group, and the like are known (for example, see Patent Document 3).
Here, “(meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position. “(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.
JP-A-8-101509 JP 2000-267286 A JP 2003-241385 A "Journal of Photopolymer Science and Technology" Vol.13, No.3 (2000), p397-404

In the future, there is a demand for new materials that can be used for lithography applications as further advancement of lithography technology and expansion of application fields are expected. For example, as the pattern becomes finer, the resist material is also required to have improved resolution. In addition, as the resolution is improved, other various lithography properties are also required to be improved. For example, when the rectangular shape of the cross-sectional shape of the resist pattern is low or the LWR (line width roughness) is large, there is a risk of adversely affecting the formation of fine semiconductor elements. 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.
Therefore, the improvement of the resist pattern shape and LWR becomes more important as the pattern becomes finer. In particular, in lithography using an electron beam or EUV, since a fine pattern formation of several tens of nanometers is a target, improvement of the resist pattern shape and LWR is extremely important.
This invention is made | formed in view of the said situation, Comprising: It aims at providing the positive resist composition and resist pattern formation method which can form a resist pattern with a favorable shape and small LWR.

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 resist composition comprising:
The base material component (A) contains a polymer compound (A1) having a structural unit (a10) derived from hydroxystyrene and a structural unit (a14) represented by the following general formula (a14-1). Is a positive resist 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^ａは２価の連結基であり、Ｒ^ｂは２価の連結基であり、Ｒ^ｃは酸解離性溶解抑制基である。］

[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, ^Ra is a divalent linking group, and R ^b is a divalent linking group. And R ^c is an acid dissociable, dissolution inhibiting group. ]

  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.

In the present specification and claims, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified.
Unless otherwise specified, the “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups.
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.
“Aliphatic” is a relative concept with respect to aromatics, and is defined to mean groups, compounds, etc. that do not have aromaticity.
The “structural unit” means a monomer unit (monomer unit) constituting a polymer compound (polymer, copolymer).
“Exposure” is a concept including general irradiation of radiation.

  ADVANTAGE OF THE INVENTION According to this invention, the positive resist composition and resist pattern formation method which can form a resist pattern with a favorable shape and small LWR can be provided.

≪Positive resist composition≫
The positive resist composition of the present invention (hereinafter sometimes referred to simply as “resist composition”) has a base component (A) (hereinafter referred to as “component (A)”) whose solubility in an alkaline developer is increased by the action of 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 2000 or more are usually used. Hereinafter, a polymer having a molecular weight of 2000 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 component (A1)) has a structural unit (a10) derived from hydroxystyrene and a structural unit (a14) represented by the general formula (a14-1). .
In addition to the structural units (a10) and (a14), the component (A1) may further have a structural unit (a15) derived from styrene.

Structural unit (a10):
In the present specification and claims, the “structural unit derived from hydroxystyrene” means a structural unit formed by cleavage of an ethylenic double bond of hydroxystyrene.
“Hydroxystyrene” refers to hydroxystyrene in a narrow sense (= a compound in which at least one hydroxyl group is bonded to the benzene ring of vinylbenzene; hereinafter, sometimes referred to as unsubstituted hydroxystyrene), and α of the unsubstituted hydroxystyrene. It is a concept that includes a hydrogen atom bonded to a carbon atom at the position substituted with a substituent (α-substituted hydroxystyrene) and derivatives thereof. That is, it is simply referred to as “hydroxystyrene”, and there is no particular limitation. The “hydroxystyrene” may be any of unsubstituted hydroxystyrene, α-substituted hydroxystyrene, and derivatives thereof. The α-position carbon atom of hydroxystyrene means a carbon atom to which a benzene ring is bonded unless otherwise specified.
Examples of the substituent that may be bonded to the α-position carbon atom in the α-substituted hydroxystyrene include an alkyl group having 1 to 5 carbon atoms, and an alkyl group having 1 to 5 carbon atoms is particularly preferable. The alkyl group is preferably a linear or branched alkyl group, 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, and pentyl. Group, isopentyl group, neopentyl group and the like.
Examples of the derivative include compounds in which a substituent is bonded to the benzene ring of unsubstituted hydroxystyrene or α-substituted hydroxystyrene.

  Preferred examples of the structural unit (a10) include structural units represented by general formula (a10-1) shown below.

［式中、Ｒ^１は水素原子または炭素数１〜５のアルキル基であり、Ｒ^２はハロゲン原子、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１〜３の整数であり、ｑは０〜４の整数であり、ｐ＋ｑは１〜５である。］

[Wherein, R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R ² is 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 1 to 3, q is an integer of 0 to 4, and p + q is 1 to 5. ]

In formula (a10-1), R ¹ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
Examples of the alkyl group for R ¹ include the same alkyl groups as those which may be bonded to the α-position carbon atom of the α-substituted hydroxystyrene in the description of hydroxystyrene.
p is an integer of 1 to 3, q is an integer of 0 to 4, and p + q is 1 to 5. However, p + q is 1-5.
p is most preferably 1.
q is preferably an integer of 0 to 2, more preferably 0 or 1, and industrially particularly preferably 0.

In formula (a10-1), the bonding position of the hydroxyl group in the phenyl group is not particularly limited. When p is 1, any of the o-position, m-position and p-position may be used, and the p-position is preferred because it is readily available and inexpensive. When p is 2 or 3, any bonding position can be combined.
Moreover, the bonding position of R ^{2 in} the phenyl group is not particularly limited. When q is 1, any of the o-position, m-position and p-position may be used. When q is an integer greater than or equal to 2, arbitrary bond positions can be combined.
When q is an integer of 2 or more, the plurality of R ² may be the same or different.

R ² is a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.
Examples of the halogen atom for R ² include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
Examples of the alkyl group for R ² include the same alkyl groups as those for R ¹ .
Examples of the halogenated alkyl group for R ^2, some or all of the hydrogen atoms in the alkyl group of the R ² can be mentioned groups substituted with a halogen atom, Examples of the halogen atom, mentioned as the halogen atom of R ² The thing similar to a thing is mentioned. The halogenated alkyl group for R ² is preferably a fluorinated alkyl group.

As the structural unit (a10), one type may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a10) in the component (A1) is preferably 5 to 95 mol%, more preferably 40 to 90 mol%, based on the total of all structural units constituting the component (A). 50 to 85 mol% is more preferable, and 55 to 80 mol% is most preferable. Within this range, moderate alkali solubility is obtained when a resist composition is obtained. In addition, lithography properties such as resolution and sensitivity are improved.

-Structural unit (a14):
The structural unit (a14) is represented by the following general formula (a14-1).

［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^ａは２価の連結基であり、Ｒ^ｂは２価の連結基であり、Ｒ^ｃは酸解離性溶解抑制基である。］

[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, ^Ra is a divalent linking group, and R ^b is a divalent linking group. And R ^c is an acid dissociable, dissolution inhibiting group. ]

In formula (a13-1), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.
The alkyl group of R is preferably a linear or branched alkyl group, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group. Group, isopentyl group, neopentyl group and the like.
Examples of the halogenated alkyl group for R include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with halogen atoms. Examples of the halogen atom in the halogenated alkyl group 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.

Preferable examples of the divalent linking group for R ^a include a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, and the like.
In the “divalent hydrocarbon group optionally having a substituent”, the hydrocarbon group “has a substituent” means that part or all of the hydrogen atoms in the hydrocarbon group are other than hydrogen atoms. It is substituted with a group or an atom.
The hydrocarbon group 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 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 —], tetramethylene group [— (CH ₂ ) ₄ —], pentamethylene group [— (CH ₂ ) ₅ —] and the like can be mentioned.
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 the cyclic aliphatic hydrocarbon group described above. Examples thereof include a group bonded to the terminal of the chain aliphatic hydrocarbon group or interposed in the middle of the chain 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).

Examples of the aromatic hydrocarbon group include aromatics of 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 removing one hydrogen atom from the nucleus of the aromatic 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;
An arylalkyl group such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., and a hydrogen atom from the nucleus of the aromatic hydrocarbon Further, an aromatic hydrocarbon group from which one is removed;
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.
Specific examples of the divalent linking group containing a hetero atom include —O—, —C (═O) —, —C (═O) —O—, and a carbonate bond (—O—C (═O) —. O-), -NH-, ^-NR04 ( ^R04 is an alkyl group)-, -NH-C (= O)-, = N- 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, R ^a is preferably a divalent hydrocarbon group which may have a substituent. The hydrocarbon group is preferably an aliphatic hydrocarbon group, more preferably a linear or branched aliphatic hydrocarbon group, and even more preferably a linear aliphatic hydrocarbon group. Especially, a linear alkylene group is preferable, a C1-C5 linear alkylene group is more preferable, and a methylene group or ethylene group is especially preferable.

^Examples of the divalent linking group for R ^b include the same groups as those described above.
In the present invention, R ^b is preferably a divalent hydrocarbon group which may have a substituent. The hydrocarbon group is preferably an aliphatic hydrocarbon group, more preferably a linear or branched aliphatic hydrocarbon group, and even more preferably a linear aliphatic hydrocarbon group. Especially, a linear alkylene group is preferable, a C1-C5 linear alkylene group is more preferable, and a methylene group or ethylene group is especially preferable.

The acid dissociable, dissolution inhibiting group for R ^c has an alkali dissolution inhibiting property that makes the entire component (A1) difficult to dissolve in an alkali developer before dissociation, and the action of an acid generated from the component (B) upon exposure. To increase the solubility of the entire component (A1) in an alkaline developer.
As the acid dissociable, dissolution inhibiting group, those proposed so far as the acid dissociable, dissolution inhibiting group of the base resin for chemically amplified resist 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. . The “(meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.
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)). A structure in which the tertiary carbon atom of the chain or cyclic alkyl group is bonded to the terminal oxygen atom of -O-). 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, “aliphatic branched” 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.
Examples of the aliphatic branched acid dissociable, dissolution inhibiting group include a group represented by -C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ). ^Wherein, R 71 ^{to R 73} each independently represents a linear alkyl group of 1 to 5 carbon atoms. The group represented by —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ) preferably has 4 to 8 carbon atoms, specifically a tert-butyl group or a 2-methyl-2-butyl group. , 2-methyl-2-pentyl group, 3-methyl-3-pentyl group and the like. A tert-butyl group is particularly preferable.

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The aliphatic cyclic group 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, and an oxygen atom (= O). , Etc.
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.
Examples of the aliphatic cyclic group include one or more hydrogens from a monocycloalkane 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 a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, and tetracycloalkane. More specifically, a group obtained by removing one or more hydrogen atoms from a monocycloalkane such as cyclopentane or cyclohexane or one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane or tetracyclododecane. And a group in which a hydrogen atom is removed. Further, a part of the carbon atoms constituting the ring of a group obtained by removing one or more hydrogen atoms from these monocycloalkanes or a group obtained by removing one or more hydrogen atoms from polycycloalkanes are etheric oxygen atoms (- O-) may be substituted.
In the present invention, the aliphatic cyclic group is preferably a polycyclic group.

Examples of the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group include:
(I) a group having a tertiary carbon atom on the ring skeleton of a monovalent aliphatic cyclic group;
(Ii) a group having a monovalent aliphatic cyclic group and a branched alkylene having a tertiary carbon atom bonded thereto, and the like.
(I) Specific examples of the group having a tertiary carbon atom on the ring skeleton of the monovalent aliphatic cyclic group are represented by the following general formulas (1-1) to (1-9). Groups and the like.
(Ii) Specific examples of the group having a monovalent aliphatic cyclic group and a branched alkylene group having a tertiary carbon atom bonded thereto include, for example, the following general formulas (2-1) to (2-1) And the group represented by (2-6).

［式中、Ｒ^１４はアルキル基であり、ｇは０〜８の整数である。］

[Wherein, R ¹⁴ represents an alkyl group, and g represents an integer of 0 to 8. ]

［式中、Ｒ^１５およびＲ^１６は、それぞれ独立してアルキル基である。］

[Wherein, R ¹⁵ and R ¹⁶ each independently represents an alkyl group. ]

The alkyl group for R ¹⁴ is preferably a linear or branched alkyl group.
The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4, and still more preferably 1 or 2. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Among these, a methyl group, an ethyl group, or an n-butyl group is preferable, and a methyl group or an ethyl group is more preferable.
The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specific examples include isopropyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group and the like, and isopropyl group is most preferable.
g is preferably an integer of 0 to 3, more preferably an integer of 1 to 3, and still more preferably 1 or 2.
Examples of the alkyl group for R ^{15 to} R ¹⁶ include the same alkyl groups as those for R ¹⁴ .
In the formulas (1-1) to (1-9) and (2-1) to (2-6), a part of the carbon atoms constituting the ring is substituted with an etheric oxygen atom (—O—). May be.
In formulas (1-1) to (1-9) and (2-1) to (2-6), a hydrogen atom bonded to a carbon atom constituting the ring may be substituted with a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, and a fluorinated alkyl group.

The “acetal-type 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 formula (p1), 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 the same alkyl groups as those described above for R. A methyl group or an ethyl group is preferable, and a methyl group is most 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は上記と同じである。］

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

Examples of the alkyl group for Y include the same alkyl groups as those described above for 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 above “aliphatic ring” 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若しく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、分岐鎖状若しく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若しく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 represents 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. And the like, in which a hydrogen atom is removed. 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 formula (p2), 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 is The terminal of R ¹⁷ 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.

  Specific examples of the acetal type acid dissociable, dissolution inhibiting group include groups represented by the following formulas (p3-1) to (p3-12).

［式中、Ｒ^１３は水素原子またはメチル基であり、ｇは前記と同じである。］

[Wherein, R ¹³ represents a hydrogen atom or a methyl group, and g is the same as defined above. ]

In the present invention, R ^c is preferably a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, and a tertiary carbon atom is formed on the ring skeleton of the above-described (i) monovalent aliphatic cyclic group. It is more preferable that the aliphatic cyclic group is a polycyclic group (aliphatic polycyclic group). Among these, a group represented by the general formula (1-1) is preferable.

  As the structural unit (a14), a structural unit represented by general formula (a14-1-1) or (a14-1-2) shown below is particularly preferable, and particularly represented by formula (a14-1-1). Are preferred.

［式中、ＲおよびＲ^１４はそれぞれ前記と同じであり、ａは１〜１０の整数であり、ｂは１〜１０の整数であり、ｔは０〜３の整数である。］

[Wherein, R and R ¹⁴ are the same as defined above, a is an integer of 1 to 10, b is an integer of 1 to 10, and t is an integer of 0 to 3, respectively. ]

In formulas (a14-1-1) to (a14-1-2), a is preferably an integer of 1 to 8, preferably an integer of 1 to 5, and most preferably 1 or 2.
b is preferably an integer of 1 to 8, preferably an integer of 1 to 5, and particularly preferably 1 or 2.
t is preferably an integer of 1 to 3, and 1 or 2 is particularly preferable.

As the structural unit (a14), one type may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a14) in the component (A1) is preferably from 5 to 70 mol%, more preferably from 10 to 65 mol%, more preferably from 15 to 60, based on the total of all the structural units constituting the component (A).
More preferred is mol%, and most preferred is 20 to 55 mol%. When it is at least the lower limit of the range, the effects of the present invention are sufficiently obtained, and when it is at most the upper limit, the balance with a single constituent unit is good and the lithography properties such as sensitivity and resolution are improved.

Structural unit (a15):
As described above, the component (A) may further have a structural unit (a15) derived from styrene in addition to the structural units (a10) and (a14). By having the structural unit (a15), heat resistance and dry etching resistance are improved when a resist composition is formed. Moreover, the solubility with respect to an alkali developing solution can be adjusted by adjusting content of a structural unit (a15).
Here, in the present specification, “structural unit derived from styrene” means a structural unit formed by cleavage of an ethylenic double bond of styrene.
“Styrene” means styrene in a narrow sense (= vinylbenzene; hereinafter, sometimes referred to as unsubstituted styrene), and a hydrogen atom bonded to the α-position carbon atom of the unsubstituted styrene is substituted with a substituent. The concept includes products (α-substituted styrene) and derivatives thereof. That is, it is simply referred to as “styrene”, and there is no particular limitation. The “styrene” may be any of unsubstituted styrene, α-substituted styrene, and derivatives thereof. The α-position carbon atom of styrene means a carbon atom to which a benzene ring is bonded unless otherwise specified.
Examples of the substituent that may be bonded to the α-position carbon atom in the α-substituted styrene include an alkyl group having 1 to 5 carbon atoms, and an alkyl group having 1 to 5 carbon atoms is particularly preferable. The alkyl group is preferably a linear or branched alkyl group, 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, and pentyl. Group, isopentyl group, neopentyl group and the like.
Examples of the derivative include those in which a substituent is bonded to the benzene ring of unsubstituted styrene or α-substituted styrene.

  Suitable examples of the structural unit (a15) include structural units represented by general formula (a15-1) shown below.

［式中、Ｒ^１は前記と同じであり、Ｒ^３はハロゲン原子、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、ｒは０〜５の整数である。］

[Wherein, R ¹ is the same as above, R ³ is a halogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, and r is an integer of 0 to 5] . ]

Wherein (A15-1), ^{R 1} is the same as ^{R 1} in the formula (A10-1).
Examples of R ³ include the same as R ² in formula (a10-1).
r is preferably an integer of 0 to 3, more preferably 0 or 1, and most preferably 0 industrially.

As the structural unit (a15), one type of structural unit may be used alone, or two or more types of structural units may be used in combination.
The proportion of the structural unit (a15) in the component (A1) is preferably 0 to 30 mol%, more preferably 0 to 20 mol%, more preferably 0 to 10 with respect to the total of all the structural units constituting the component (A). More preferred is mol%.

The component (A1) may have other structural units other than the structural units (a10), (a14) and (a15) 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 (a10), (a14), and (a15). For ArF excimer laser, for KrF excimer laser, Many things conventionally known as what is used for resist resin for EUV, EB, etc. can be used.
Preferred examples of the other structural unit include the structural unit (a3), structural unit (a4), structural unit (a16), structural unit (a17), and structural unit (a18) shown below. . By combining these structural units, lithography characteristics are improved.

-Structural unit (a3):
The structural unit (a3) is a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group. When the component (A1) has the structural unit (a3), the hydrophilicity of the component (A1) is increased, the affinity with the developer is increased, the alkali solubility in the exposed area is improved, and the resolution is improved. Contributes to improvement.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom. A hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group), and a polycyclic aliphatic hydrocarbon group (aliphatic polycyclic group). Is mentioned. As the aliphatic polycyclic group, for example, a resin for a resist composition for ArF excimer laser can be appropriately selected and used from among many proposed ones. The aliphatic polycyclic group preferably has 7 to 30 carbon atoms. Specific examples include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane, or the like. Specific examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, there are groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane. Industrially preferable.
The structural unit (a3) includes, among the above, an aliphatic polycyclic group containing a hydroxyalkyl group in which a part of hydrogen atoms of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with a fluorine atom. A structural unit derived from an acrylate ester is more preferred.

  The structural unit (a3) is derived from a hydroxyethyl ester of acrylic acid when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms. When the hydrocarbon group is a polycyclic group, a structural unit represented by the following formula (a3-1), a structural unit represented by (a3-2), (a3-3) The structural unit etc. which are represented by these are mentioned as a preferable thing.

（式中、Ｒは前記に同じであり、ｊは１〜３の整数であり、ｋは１〜３の整数であり、ｔ’は１〜３の整数であり、ｌは１〜５の整数であり、ｓは１〜３の整数である。）

(Wherein R is the same as above, j is an integer of 1 to 3, k is an integer of 1 to 3, t 'is an integer of 1 to 3, and l is an integer of 1 to 5) And s is an integer of 1 to 3.)

In formula (a3-1), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl 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 3rd position of the adamantyl group is particularly preferred.
In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group.
In formula (a3-3), t ′ is preferably 1. 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 carboxy group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

-Structural unit (a4):
The structural unit (a4) is a structural unit derived from an acrylate ester containing a non-acid-dissociable aliphatic polycyclic group. Here, “acid non-dissociable” means that the acid does not dissociate due to the action of the acid generated from the component (B).
Examples of the aliphatic polycyclic group in the structural unit (a4) include those similar to those exemplified in the case of the structural unit (a3). For the ArF excimer laser and the KrF excimer laser ( A number of hitherto known materials can be used as the resin component of the resist composition (preferably for ArF excimer laser). In particular, at least one selected from a tricyclodecanyl group, an adamantyl group, a tetracyclododecanyl group, an isobornyl group, and a norbornyl group is preferable in terms of industrial availability. These aliphatic polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include structural units represented by the following general formulas (a4-1) to (a4-5).

［式中、Ｒは前記と同じである。］

[Wherein, R is the same as defined above. ]

Structural unit (a16):
The structural unit (a16) is a structural unit in which a hydroxyl group in a structural unit derived from hydroxystyrene is protected with an acid dissociable, dissolution inhibiting group. Examples of the acid dissociable, dissolution inhibiting group include the same acid dissociable, dissolution inhibiting groups as those described above for the structural unit (a14).
As the structural unit (a16), a structural unit in which the hydroxyl group of the formula (a10-1) is protected with an acetal acid dissociable, dissolution inhibiting group is preferable.

Structural unit (a17):
The structural unit (a17) is a structural unit derived from an acrylate ester having a structure in which an acid dissociable, dissolution inhibiting group is directly bonded to a carbonyl group of acrylic acid. Examples of the acid dissociable, dissolution inhibiting group include the same acid dissociable, dissolution inhibiting groups as those described above for the structural unit (a14).
Specific examples of the structural unit (a17) include structural units represented by general formula (a17-1) shown below.
In the formula, examples of R and X ¹ include the same as R and R ^c in the formula (a14-1).

［式中、Ｒは前記と同じであり、Ｘ^１は酸解離性溶解抑制基である。］

[Wherein, R is the same as defined above, and X ¹ represents an acid dissociable, dissolution inhibiting group. ]

Structural unit (a18):
The structural unit (a18) is a structural unit having a site that generates an acid upon exposure.
Examples of the structural unit (a18) include structural units described in JP-A-2006-45311.

In the component (A1), one of these other structural units may be used alone, or two or more of these structural units may be used in combination.
However, in consideration of the effect of the present invention, in the component (A1), the total proportion of the structural units (a10), (a14) and (a15) is based on the total of all the structural units constituting the component (A1). 70 mol% or more, preferably 90 mol% or more, more preferably 100 mol%. That is, it is particularly preferable that the component (A1) does not contain a structural unit other than the structural units (a10), (a14), and (a15).

The component (A1) is preferably a copolymer having the structural units (a10) and (a14). Examples of the copolymer include a copolymer composed of the structural units (a10) and (a14), and a structural unit. Examples thereof include copolymers composed of (a10), (a14) and (a15). These copolymers further include at least one component selected from the group consisting of the structural unit (a3), the structural unit (a4), the structural unit (a16), the structural unit (a17), and the structural unit (a18). You may have a unit.
In particular, the component (A1) is preferably a copolymer having two structural units represented by the following general formula (A1-11), and is preferably a copolymer comprising the two structural units. Most preferred.

［式中、Ｒ^１、Ｒ、ａ、ｂおよびＲ^１４はそれぞれ前記と同じである。］

[Wherein, R ¹ , R, a, b and R ¹⁴ are the same as defined above. ]

  The component (A1) can be produced using a known production method. For example, a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN) as a monomer for deriving each structural unit, etc. Can be produced through a polymerization step. Specifically, for example, hydroxystyrene in which a hydroxyl group is protected with a protecting group such as an acetyl group and a compound (I) represented by the following general formula (I) are copolymerized, and the resulting copolymer is obtained. A copolymer having the structural units (a10) and (a14) is obtained by adding a base to deprotect the protective group. At this time, the base used for deprotection is preferably a weak base such as aniline in order to prevent decomposition of the structural unit (a14).

［式中、Ｒ、Ｒ^ａ、Ｒ^ｂ、Ｒ^ｃはそれぞれ前記と同じである。］

[Wherein, R, R ^a , R ^b and R ^c are the same as defined above. ]

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
A commercially available monomer may be used as the monomer for deriving each structural unit, or the monomer may be synthesized using a known method.
For example, the compound (I) can be produced by the production method (1) shown below.
Production method (1): Compound represented by general formula (I-1) (hereinafter referred to as compound (I-1)) and compound represented by general formula (I-2) (hereinafter referred to as compound) (I-2)) to obtain a compound represented by the general formula (I-3) (hereinafter referred to as compound (I-3)) (hereinafter referred to as the first step). And a step of obtaining compound (I) by reacting compound (I-3) with a compound represented by the following general formula (I-4) (hereinafter referred to as compound (I-4)) A manufacturing method including the second step).

［式中、Ｒ、Ｒ^ａ、Ｒ^ｂ、Ｒ^ｃはそれぞれ前記と同じであり、Ｘ^１１およびＸ^１２はそれぞれ独立してハロゲン原子である。］

[Wherein, R, R ^a , R ^b and R ^c are the same as defined above, and X ¹¹ and X ¹² are each independently a halogen atom. ]

In the formula, examples of the halogen atom for X ¹¹ and X ¹² include a bromine atom, a chlorine atom, an iodine atom, and a fluorine atom.
As the halogen atom for X ¹¹ and X ¹² , a chlorine atom or a bromine atom is preferable because of excellent reactivity.

"First step"
Compound (I-1) and compound (I-2) can be reacted by a known method. For example, the method of making compound (I-1) and compound (I-2) contact in reaction solvent in presence of a base is mentioned. This method can be carried out, for example, by adding compound (I-2) to a solution in which compound (I-1) is dissolved in a reaction solvent in the presence of a base.
As compound (I-1) and compound (I-2), commercially available compounds may be used or synthesized.
Examples of the compound (I-2) include 2-methyl-2-adamantyloxycarbonylmethyl chloride, 2-ethyl-2-adamantyloxycarbonylmethyl chloride, 1-methyl-1-cyclohexyloxycarbonylmethyl chloride, 1-ethyl-1 -Cyclohexyloxycarbonylmethyl chloride, 1-methyl-1-cyclopentyloxycarbonylmethyl chloride, 1-ethyl-1-cyclopentyloxycarbonylmethyl chloride and the like.
Any reaction solvent may be used as long as it can dissolve the starting compounds (I-1) and (I-2). Specifically, tetrahydrofuran (THF), acetone, dimethylformamide (DMF), dimethylacetamide , Dimethyl sulfoxide (DMSO), acetonitrile and the like.
Examples of the base include inorganic bases such as sodium hydride and K ₂ CO ₃ ; organic bases such as triethylamine, 4-dimethylaminopyridine (DMAP) and pyridine. In the first step, K ₂ CO ₃ is particularly preferably used.
The amount of compound (I-2) added is preferably about 1 to 100 moles, more preferably 1 to 50 moles, with respect to compound (I-1).
0-50 degreeC is preferable and, as for reaction temperature, 5-40 degreeC is more preferable. The reaction time varies depending on the reactivity and reaction temperature of the compound (I-1) and the compound (I-2), but usually 1 to 24 hours are preferable, and 3 to 12 hours are more preferable.

  After completion of the reaction, the reaction solution may be used in the next step as it is, or the compound (I-3) in the reaction solution may be isolated and purified. For isolation and purification, conventionally known methods can be used. For example, concentration, solvent extraction, crystallization, recrystallization, chromatography and the like can be used alone or in combination of two or more.

"Second step"
The method for reacting compound (I-3) with compound (I-4) is not particularly limited. For example, the presence of a base in the solution in which compound (I-3) obtained in the first step is dissolved Below, the method of adding a compound (I-4) is mentioned.
As the solution in which the compound (I-3) is dissolved, the reaction solution obtained in the first step may be used as it is, and the compound (I-3) isolated and purified from the reaction solution is dissolved in the reaction solvent. A solution may be used.
Any reaction solvent may be used as long as it can dissolve the raw material compound (I-3), and examples thereof include the same reaction solvents as those mentioned in the first step.
Examples of the base include the same bases as those mentioned in the first step. In the first step, triethylamine is particularly preferably used.
The amount of compound (I-4) to be added is preferably about 1 to 2 moles, more preferably 1 to 1.5 moles, relative to compound (I-3).
The reaction temperature is preferably 0 to 50 ° C, more preferably 5 to 40 ° C, and most preferably a reaction at room temperature.
The reaction time varies depending on the reactivity of the compounds (I-3) and (I-4), the reaction temperature, and the like, but usually 1 to 24 hours are preferable, and 3 to 12 hours are more preferable.

After completion of the reaction, the compound (I) in the reaction solution may be isolated and purified. For isolation and purification, conventionally known methods can be used. For example, concentration, solvent extraction, crystallization, recrystallization, chromatography and the like can be used alone or in combination of two or more.
The structure of the compound obtained in the above step 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. It can be confirmed by general organic analysis methods such as elemental analysis and X-ray crystal diffraction.

The mass average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 2000 to 50000, more preferably 3000 to 30000, and 5000 to 20000. Most preferred. When it is smaller than the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist. When it is larger than the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Further, the dispersity (Mw / Mn) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5. In addition, Mn shows a number average molecular weight.

In the component (A), as the component (A1), one type may be used alone, or two or more types may be used in combination.
In view of the effect of the present invention, the proportion of the component (A1) in the component (A) is preferably 50% by mass or more, more preferably 75% by mass, and more preferably 80% by mass with respect to the total mass of the component (A). More preferably, it may be 100% by mass.

The resist composition of the present invention does not correspond to the component (A1) as the component (A), and is a base material component (hereinafter referred to as “component (A2)”) whose solubility in an alkaline developer is increased by the action of an acid. It may contain.
The component (A2) is not particularly limited, and many conventionally known base components for chemically amplified positive resist compositions (for example, for ArF excimer laser, for KrF excimer laser, for EB, Any base resin selected from EUV base resins) may be used. Moreover, you may contain the nonpolymer (low molecular compound) whose molecular weight is 500-4000.
(A2) A component may be used individually by 1 type and may be used in combination of 2 or more type.

  In the 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, and poly (bissulfonyl) diazomethanes. 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良いアルキル基、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 —CO—O—R ⁵¹ [wherein, R ⁵⁰ represents an alkylene group, and R ⁵¹ represents an acid-dissociable group. ] 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 —CO—O—R ⁵¹ in which the hydrogen atom of the aryl group may be substituted, the alkylene group in R ⁵⁰ is preferably a linear or branched alkylene group, and the carbon number thereof 1-5 are preferable. 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 (acid generated from the component (B) at the time of exposure). For example, in the general formula (a13-1), those similar to the acid dissociable, dissolution inhibiting groups as those mentioned as X ² can be mentioned. Among them, the tertiary alkyl ester type is preferable.

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 decanyl 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.

When any two of R ¹ ″ to R ³ ″ in the formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, a 3 to 10 membered ring including the sulfur atom is formed. It is preferable that a 5- to 7-membered ring is formed.
When any two of R ¹ ″ to R ³ ″ in formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, the remaining one may be an aryl group preferable. Examples of the aryl group include the same aryl groups as R ¹ ″ to R ³ ″.

Of the cation moieties 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 triphenylmethane. Specific examples of preferred skeletons include cation moieties represented by the following formulas (I-1-1) to (I-1-8).

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-1-10) to (I-1-11).
In the following formula (I-1-10), R ⁹ is a phenyl group, a naphthyl group, or an alkyl group having 1 to 5 carbon atoms which may have a substituent.
In the following formula (I-1-11), R ¹⁰ represents a phenyl group, a naphthyl group, an alkyl group having 1 to 5 carbon atoms, an alkoxy group, or a hydroxyl group, which may have a substituent.
u is an integer of 1 to 3, and 1 or 2 is most preferable.

［式中、Ｒ^９は、置換基を有していてもよいフェニル基、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、ナフチル基、炭素数１〜５のアルキル基、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 optionally having a substituent, a naphthyl group or an alkyl group having 1 to 5 carbon atoms, and R ¹⁰ is a phenyl group optionally having a substituent, A naphthyl group, an alkyl group having 1 to 5 carbon atoms, an alkoxy group or a hydroxyl group, and u is an integer of 1 to 3; ]

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 a halogen atom, a hetero atom, an alkyl group, and a formula: XQ ^1- [wherein 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 — and the like. Alkylethylene groups; trimethylene groups (n-propylene groups) [—CH ₂ CH ₂ CH ₂ —]; alkyls such as —CH (CH ₃ ) CH ₂ CH ₂ — and —CH ₂ CH (CH ₃ ) CH ₂ — trimethylene; tetramethylene group _[-CH 2 _CH 2 C _{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; pentamethylene 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 hetero atom may be composed of only the hetero atom, or may be a group containing a group or atom other than the hetero atom.
Specific examples of the substituent for substituting a part of the carbon 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, an acyl group, etc.), —S—, —S (═O) ₂ —, — S (= O) ₂ —O— and the like can be mentioned. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent for substituting part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and a cyano group.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.

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, decanyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, henocosyl 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.
Among the above, the unsaturated hydrocarbon group is particularly preferably a propenyl group.

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 have been removed from a monocycloalkane; a group in which one or more hydrogen atoms have been 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 the following formulas (L1) to (L5), (S1) to (S4), and the like.

［式中、Ｑ”は炭素数１〜５のアルキレン基、−Ｏ−、−Ｓ−、−Ｏ−Ｒ^９４−または−Ｓ−Ｒ^９５−であり、Ｒ^９４およびＲ^９５はそれぞれ独立に炭素数１〜５のアルキレン基であり、ｍは０または１の整数である。］

[Wherein, Q ″ is an alkylene group having 1 to 5 carbon atoms, —O—, —S—, —O—R ⁹⁴ — or —S—R ⁹⁵ —, and R ⁹⁴ and R ⁹⁵ are each independently carbon. An alkylene group of 1 to 5 and m is an integer of 0 or 1.]

In the formula, examples of the alkylene group for Q ″, R ⁹⁴ and R ⁹⁵ include the same alkylene groups as those described above for R ^{91 to} R ⁹³ .
In these aliphatic cyclic groups, a part of hydrogen atoms bonded to carbon atoms constituting the ring structure may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
As said alkyl group, a C1-C5 alkyl group is preferable, and it is especially preferable that they are a methyl group, an ethyl group, a propyl group, n-butyl group, and a tert- butyl group.
Examples of the alkoxy group and the halogen atom are the same as those exemplified as the substituent for substituting part or all of the hydrogen atoms.

In the present invention, 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. The polycyclic aliphatic cyclic group is preferably a group obtained by removing one or more hydrogen atoms from the polycycloalkane, the above (L2) to (L5), (S3) to (S4), and the like.

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.
Moreover, the onium salt which replaced the anion part of these onium salts with alkyl sulfonates, such as methanesulfonate, n-propanesulfonate, n-butanesulfonate, n-octanesulfonate, can also 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、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は置換基である。］

[Wherein, p is an integer of 1 to 3, q1 to q2 are each independently an integer of 1 to 5, q3 is an integer of 1 to 12, and r1 to r2 are each independently 0 to 3] It is an integer, g is an integer of 1 to 20, t3 is an integer of 1 to 3, and R ⁷ is a substituent. ]

［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 are the same as those described above as the substituent that the aliphatic hydrocarbon group may have and the substituent that the aromatic hydrocarbon group may have in X. Can be 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.
r1 to r2 and w1 to w5 are each preferably an integer of 0 to 2, and more 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.

  Moreover, the sulfonium salt which has a cation part represented by the following general formula (b-5) or (b-6) can also be used as an onium salt type | system | group acid generator.

［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 R ^{41 to} R ⁴⁶ , the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a linear or branched alkyl group, and a methyl group, an ethyl group, a propyl group, an isopropyl group, n A 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.

The anion part of the sulfonium salt having a cation part represented by the formula (b-5) or (b-6) is not particularly limited, and is the same as the anion part of the onium salt acid generators proposed so far. It may be a thing. Examples of the anion moiety include fluorinated alkyl sulfonate ions such as the anion moiety (R ⁴ ″ SO ₃ ⁻ ) of the onium salt acid generator represented by the general formula (b-1) or (b-2). The anion part represented by the general formula (b-3) or (b-4) 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 of R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and 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 a heteroaryl group in which a part of carbon atoms constituting the ring of these groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. 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 of 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).
The content of the component (B) in the positive resist composition of the present invention is preferably 0.5 to 50 parts by mass and more preferably 1 to 40 parts by mass with respect to 100 parts by mass of the component (A). 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, and aliphatic amines, particularly 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 , Tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine, etc .; diethanolamine, triethanolamine, diisopropanolamine Triisopropanolamine, 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.
Examples of the aromatic amine include aniline, pyridine, 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, diphenylamine, triphenylamine, and tribenzylamine.
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.
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, cyclohexanone, 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 or 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.

≪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 For 60 to 90 seconds, using an exposure apparatus such as an ArF exposure apparatus, an electron beam drawing apparatus, or an EUV exposure apparatus, exposure through a mask pattern, or drawing by direct irradiation of an electron beam without using a mask pattern, etc. Then, PEB (post-exposure heating) is applied for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature 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 an organic antireflection film (organic BARC).
The wavelength used for the 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 effective for KrF excimer laser, ArF excimer laser, EB or EUV, and particularly effective for 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.

According to the present invention, a resist pattern having a good shape and a small LWR can be formed. In addition, resolution, sensitivity, etc. are also good.
The reason why the above effect is obtained is not clear, but it is considered that the combination of the structural unit (a10) and the structural unit (a14) in the component (A) contributes to improvement in resolution, sensitivity, and the like. That is, since the structural unit (a14) has a relatively long side chain with a specific structure, the affinity between the long side chain and the acid generator is good, and the uniformity of the acid generator distribution in the film is improved. Therefore, it is estimated that LWR is reduced. The effect of LWR reduction is estimated to be more effective as the side chain of (a14) is longer. Moreover, it has sufficient heat resistance in lithography. Furthermore, it is considered that the resolution and sensitivity are improved by combining the structural unit (a10). The improvement in resolution and LWR becomes more important as the pattern becomes finer due to EUV exposure or the like.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.
[Polymer synthesis example 1]
Under a nitrogen atmosphere, PGMEA was placed in a flask equipped with a nitrogen inlet, a stirrer, a condenser and a thermometer, and the temperature of the hot water bath was raised to 80 ° C. while stirring. Next, 2,2′-azobisisobutyronitrile (AIBN) as a polymerization initiator and a monomer mixture of monomer (1) / monomer (2) = 65/45 (molar ratio) shown below were charged. The monomer PGMEA solution was dropped into the flask over 4 hours at a constant rate using a dropping device, and then kept at 80 ° C. for 2 hours. Thereafter, the reaction solution was returned to room temperature. Subsequently, 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 separated by filtration and dissolved in methanol, and then 120 mol% aniline was stirred in the solution at 70 ° C. for 60 hours. 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 the target polymer compound (1).
About this high molecular compound, the mass mean molecular weight (Mw) of standard polystyrene conversion calculated | required by GPC measurement was 9,500, and dispersion degree (Mw / Mn) was 1.68.
The copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is m / n = 58.9 / 41. 1

[Monomer Synthesis Example 1 (Synthesis of Monomer (2))]
Monomer (2) used in Polymer Synthesis Example 1 was synthesized according to the following procedure.
A 2 L three-necked flask equipped with a thermometer, a condenser and a stirrer was charged with 37.6 g (494 mmol) of glycolic acid, 700 mL of DMF, 86.5 g (626 mmol) of potassium carbonate, and 28.3 g (170 mmol) of potassium iodide at room temperature. For 30 minutes. Then, 300 mL of dimethylformamide in 100 g (412 mmol) of 2-methyl-2-adamantyl chloroacetate was slowly added. The temperature was raised to 40 ° C. and stirred for 4 hours. After completion of the reaction, 2000 mL of diethyl ether was added and filtered, and the resulting solution was washed 3 times with 500 mL of distilled water. Crystallization was performed using a mixed solution of toluene (300 mL) and heptane (200 mL) to obtain the target product (2- (2- (2-methyl-2-adamantyloxy) -2-oxoethoxy) -2-oxoethanol). Was obtained as a colorless solid (78 g, yield 67%, GC purity 99%).
The instrumental analysis results of the obtained compound were as follows.
¹ H-NMR: 1.59 (d, 2H, J = 12.5 Hz), 1.64 (s, 3H), 1.71 to 1.99 (m, 10H), 2.29 (m, 2H) 2.63 (t, 1H, J = 5.2 Hz), 4.29 (d, 2H, J = 5.2 Hz), 4.67 (s, 2H).
¹³ C-NMR: 22.35, 26.56, 27.26, 32.97, 34.54, 36.29, 38.05, 60.54, 61.50, 89.87, 165.97, 172 .81.
GC-MS: 282 (M +, 0.02%), 165 (0.09%), 149 (40%), 148 (100%), 133 (22%), 117 (2.57%), 89 ( 0.40%).
From the above results, it was confirmed that the obtained compound was 2- (2- (2-methyl-2-adamantyloxy) -2-oxoethoxy) -2-oxoethanol.

Next, 165 g (584 mmol) of 2- (2- (2-methyl-2-adamantyloxy) -2-oxoethoxy) -2-oxoethanol was added to a 2 L three-necked flask equipped with a thermometer, a condenser and a stirrer. , THF 2000 mL, triethylamine 105 mL (754 mmol) and p-methoxyphenol 0.165 g (1000 ppm) were added and dissolved. After dissolution, 62.7 mL (648 mmol) of methacryloyl chloride was slowly added in an ice bath, warmed to room temperature, and stirred for 3 hours. After completion of the reaction, 1000 mL of diethyl ether was added and washed 5 times with 200 mL of distilled water. The extract was concentrated to obtain 198 g (yield 97%, GC purity 99%) of the desired product (compound (2)) as a colorless liquid.
The instrumental analysis result of the obtained compound (2) was as follows.
¹ H-NMR: 1.58 (d, J = 12.5 Hz, 2H), 1.63 (s, 3H), 1.71 to 1.89 (m, 8H), 1.98 (s, 3H) , 2.00 (m, 2H), 2.30 (m, 2H), 4.62 (s, 2H), 4.80 (s, 2H), 5.66 (m, 1H), 6.23 ( m, 1H).
¹³ C-NMR: 18.04, 22.15, 26.42, 27.14, 32.82, 34.38, 36.11, 37.92, 60.44, 61.28, 89.42, 126 79, 135.18, 165.61, 166.30, 167.20.
GC-MS: 350 (M +, 1.4%), 206 (0.13%), 149 (47%), 148 (100%), 133 (20%), 69 (37%).

(Example 1, Comparative Examples 1-2)
<Preparation of positive resist composition>
Each component shown in Table 1 was mixed and dissolved to prepare a positive resist composition.

In Table 1, the numerical value in [] is the blending amount (part by mass).
Each abbreviation in Table 1 has the following meaning.
(A) -1: the polymer compound (1).
(A ′)-1: A copolymer (Mw = 10000, Mw / Mn = 1.4) in which m / n = 70/30 (molar ratio) in the following structural formula (A ′)-0.
(A ′)-2: A copolymer (Mw = 10000, Mw / Mn = 1.4) in which m / n = 60/40 (molar ratio) in the following structural formula (A ′)-0.
(B) -1: Tolphenylsulfonium nonafluorobutanesulfonate.
(D) -1: tri-n-octylamine.
(E) -1: salicylic acid.
(S) -1: Mixed solvent of PGMEA / PGME = 6: 4.

The following evaluation was performed about each obtained positive resist composition.
<Evaluation of lithography properties>
[Evaluation of resist pattern formation]
The positive resist composition of each example was coated on an 8-inch silicon substrate that had been subjected to hexamethyldisilazane (HMDS) treatment at 90 ° C. for 30 seconds, on a coater (“Clean Track ACT-8”, Tokyo Electron Limited). And a baking process (PAB) for 60 seconds at the temperature shown in Table 2 to form a resist film (film thickness 60 nm).
The resist film is drawn (exposure) at an acceleration voltage of 70 keV using an electron beam lithography machine HL-800D (VSB) (manufactured by Hitachi), and a baking process (PEB) for 60 seconds at the temperature shown in Table 2 is performed. After further development for 30 seconds using a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) (trade name: NMD-3, manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 23 ° C., Rinse with pure water for 15 seconds.
As a result, in each example, a line and space (L / S) pattern having a line width of 150 nm and a pitch of 300 nm was formed.

[LWR evaluation]
In the resist pattern formation, an optimum exposure amount Eop (μC / cm ² ) for forming an L / S pattern having a line width of 150 nm and a pitch of 300 nm is obtained, and the L / of the line width of 150 nm and the pitch of 300 nm formed by the Eop is obtained. With respect to the S pattern, the line width was measured at five locations in the longitudinal direction of the line with a length measuring SEM (scanning electron microscope, trade name: S-9220, manufactured by Hitachi, Ltd.), and the standard deviation (s) of 3 was obtained from the result. Double value (3 s) was calculated as a measure of LWR. 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. The results are shown in Table 2.

[Shape evaluation]
The cross-sectional shape of the L / S pattern having a line width of 150 nm and a pitch of 300 nm formed by Eop was observed using a scanning electron microscope (trade name: S-9220, manufactured by Hitachi, Ltd.). Evaluated by criteria. The results are shown in Table 2.
A: The side wall of the line is perpendicular to the substrate surface at the interface with the substrate and has a high rectangularity
X: T-TOP shape and low rectangularity.

  As shown in the results of Table 2, the resist composition of Example 1 according to the present invention had a smaller LWR and a better shape than the resist compositions of Comparative Examples 1-2. .

Claims (5)

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 base material component (A) contains a polymer compound (A1) having a structural unit (a10) derived from hydroxystyrene and a structural unit (a14) represented by the following general formula (a14-1). A positive resist composition characterized by the above.

[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, ^Ra is a divalent linking group, and R ^b is a divalent linking group. And R ^c is an acid dissociable, dissolution inhibiting group. ]   The proportion of the structural unit (a14) in the polymer compound (A1) is in the range of 5 to 70 mol% with respect to the total of all the structural units constituting the polymer compound (A1). The positive resist composition as described. The positive resist composition according to claim 1, wherein the structural unit (a10) is represented by the following general formula (a10-1).

[Wherein, R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R ² is 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 1 to 3, q is an integer of 0 to 4, and p + q is 1 to 5. ]   Furthermore, the positive resist composition as described in any one of Claims 1-3 containing a nitrogen-containing organic compound (D).   A step of forming a resist film on the support using the positive resist composition according to any one of claims 1 to 4, a step of exposing the resist film, and an alkali development of the resist film A resist pattern forming method including a step of forming a resist pattern.