JP2011013501A - Positive type resist composition, method of forming resist pattern and high molecular compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive type resist composition having excellent lithography characteristic, a new high molecular compound useful as a base material component of the positive type resist composition, and also to provide a method of forming a resist pattern using the positive type resist composition.SOLUTION: This positive type resist composition contains: a base material component (A) increased in solubility to an alkali liquid developer by action of acid; and an acid generating agent component (B) adapted to generate acid by exposure. The base material component (A) contains a high molecular compound (A1) having a structural unit (a1) derived from acrylic ester containing an acid dissociative dissolution inhibiting group, and the molecular weight dispersive power (Mw/Mn) of the base material component (A) is 1.01-1.50.

Description

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

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, and the resist film is selectively exposed to light such as light or an electron beam through a mask on which a predetermined pattern is formed. And a development process is performed to form a resist pattern having a predetermined shape on the resist film.
A resist material in which the exposed portion changes to a property that dissolves in the developer is referred to as a positive type, and a resist material that changes to a property in which the exposed portion does not dissolve in the developer is referred to as a negative type.
In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, pattern miniaturization has rapidly progressed 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 a pattern with fine dimensions.
As a resist material that satisfies such requirements, a chemically amplified resist composition containing a base material component 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. ing.
For example, as a positive chemically amplified resist composition, a composition containing a resin component (base resin) whose solubility in an alkaline developer is increased by the action of an acid and an acid generator component is generally used. Yes. When such a resist film formed using the resist composition is selectively exposed at the time of resist pattern formation, an acid is generated from the acid generator in the exposed portion, and the alkali developer of the resin component is generated by the action of the acid. As a result, the exposed area becomes soluble in an alkaline developer.
On the other hand, the negative chemically amplified resist contains, for example, a resin component having a carboxy group, a crosslinking agent having an alcoholic hydroxyl group, and an acid generator, and the action of an acid generated from the acid generator when forming a resist pattern. As a result of the reaction between the carboxyl group of the resin component and the alcoholic hydroxyl group of the cross-linking agent, the resin component changes from alkali-soluble to insoluble.
Currently, as a resist base resin used in ArF excimer laser lithography and the like, a resin (acrylic resin) having a structural unit derived from (meth) acrylic acid ester in its main chain because of its excellent transparency near 193 nm Etc. are generally used (see, for example, Patent Documents 1 and 2).
At present, as a base resin for a chemically amplified resist, a resin containing a plurality of structural units is used in order to improve lithography properties and the like. For example, in the case of the positive type, it usually contains a structural unit having an acid dissociable, dissolution inhibiting group that is dissociated by the action of an acid generated from an acid generator, and further has a structural unit having a polar group such as a hydroxyl group, a lactone structure. The thing containing the structural unit which has is used. Among these, the structural unit having a lactone structure is generally considered to contribute to the improvement of lithography properties by improving the adhesion of the resist film to the substrate and the affinity with an alkali developer.

On the other hand, living radical polymerization is known as a polymerization method for polymer compounds. Living radical polymerization is a polymerization method that enables precise control of the molecular structure while maintaining the simplicity and versatility of radical polymerization, and is very effective in the synthesis of new polymer materials. As a typical example of living radical polymerization, living radical polymerization using TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) as an initiator has been reported by Jones et al. (See Patent Document 2). ). Although this method makes it possible to control the molecular weight and molecular weight distribution, it requires a high polymerization temperature of 130 ° C. and is difficult to apply to monomers having a thermally unstable functional group.
Organic tellurium compounds are known as living radical polymerization initiators that enable precise control of molecular weight and molecular weight dispersity (Mw / Mn) under mild conditions. By living radical polymerization using an organic tellurium compound as an initiator, a polymer compound having a narrow molecular weight dispersity (Mw / Mn) can be synthesized under mild conditions (Patent Documents 3 to 6).

JP 2003-241385 A JP-A-6-199916 JP 2004-323893 A JP 2005-126659 A JP 2006-299278 A JP 2008-247919 A

In recent years, the miniaturization of resist patterns has further progressed, and the conventional resist composition is further required to be able to form a resist pattern having a favorable shape in resist pattern formation. More specifically, among various lithographic properties, for example, development of a resist material that is excellent in roundness in the case of CDU (dimensional uniformity) representing the dimensional uniformity of a resist pattern or contact holes is desired.
The present invention has been made in view of the above circumstances, and is a positive resist composition capable of forming a pattern having a good shape, and a novel polymer compound useful as a base component of the positive resist composition, It is another object of the present invention to provide a resist pattern forming method using the positive resist composition.

In order to achieve the above object, 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 component (A) has a structural unit (a1) derived from an acrylic ester containing a structural unit (a0) represented by the following general formula (a0-1) and an acid dissociable, dissolution inhibiting group. A positive resist composition comprising a molecular compound (A1) and having a molecular weight dispersity (Mw / Mn) of the substrate component (A) of 1.01 to 1.50.

［式中、Ｒ^１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^２は２価の連結基であり、Ｒ^３は、その環骨格中に−ＳＯ_２−を含む環式基である。］

[Wherein, R ¹ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ² is a divalent linking group, and R ³ is a ring skeleton thereof. It is a cyclic group containing —SO ₂ — therein. ]

  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.

  The third aspect of the present invention has a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group. The polymer compound has a molecular weight dispersity (Mw / Mn) of 1.01-1.50.

［式中、Ｒ^１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^２は２価の連結基であり、Ｒ^３は、その環骨格中に−ＳＯ_２−を含む環式基である。］

[Wherein, R ¹ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ² is a divalent linking group, and R ³ is a ring skeleton thereof. It is a cyclic group containing —SO ₂ — therein. ]

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

  According to the present invention, there are provided a resist composition particularly excellent in dimensional controllability as a lithography property, a polymer compound useful as a base component of the positive resist composition, and a resist pattern forming method using the resist composition. it can.

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

<(A) component>
The component (A) of the present invention has a high structural unit (a1) derived from the structural unit (a0) represented by the general formula (a0-1) and an acrylate ester containing an acid dissociable, dissolution inhibiting group. It contains molecular compound (A1) (hereinafter referred to as component (A1)), and the molecular weight dispersity (Mw / Mn) of the component (A) is 1.01-1.50.

[Polymer Compound (A1)]
The component (A1) is a polymer compound having the structural units (a0) and (a1).
In addition to the structural units (a0) and (a1), the component (A1) preferably further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group.
In addition to the structural units (a0) and (a1) or in addition to the structural units (a0), (a1) and (a2), the component (A1) is further a polar group-containing aliphatic hydrocarbon group. It is preferable to have a structural unit (a3) derived from an acrylate ester containing

(Structural unit (a0))
The structural unit (a0) is a structural unit represented by the general formula (a0-1).
In formula (a0-1), R ¹ 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 ¹ is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group. Tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like.
The halogenated alkyl group having 1 to 5 carbon atoms of R ¹ is a group in which part or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
R ¹ 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.

In formula (a0-1), R ² is a divalent linking group.
Preferred examples of R ² include a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, and the like.
The term “having a substituent” for the hydrocarbon group means that part or all of the hydrogen atoms in the hydrocarbon group are substituted with groups or atoms other than hydrogen atoms.
The hydrocarbon group 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 chain-like aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

Examples of the aliphatic hydrocarbon group including 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 includes the chain described above. And a group that is bonded to the terminal of the chain-like aliphatic hydrocarbon group or intervenes in the middle of the chain-like aliphatic hydrocarbon group.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic group, a group in which two hydrogen atoms are 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;
A benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, an 1-naphthylethyl group, an arylalkyl group such as a 2-naphthylethyl group, etc., and a hydrogen atom from the nucleus of the aromatic hydrocarbon In addition, an aromatic hydrocarbon group or the like from which one is removed may be mentioned.
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.

R ² may or may not have an acid dissociable site in its structure. The “acid-dissociable site” refers to a site in the organic group that is dissociated by the action of an acid generated by exposure. When R ² has an acid dissociable portion, it is preferable that it preferably has an acid dissociable portion having a tertiary carbon atom.

In the present invention, the divalent linking group for R ² is preferably an alkylene group, a divalent aliphatic cyclic group or a divalent linking group containing a hetero atom. Among these, an alkylene group is particularly preferable.
When R ² is an alkylene group, the alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms. It is most preferable that it is number 1-3. Specific examples include the same linear alkylene groups and branched alkylene groups as mentioned above.
When R ² is a divalent aliphatic cyclic group, the aliphatic cyclic group is the same as the cyclic aliphatic hydrocarbon group mentioned in the above “aliphatic hydrocarbon group containing a ring in the structure”. Can be mentioned.
The aliphatic cyclic group is particularly preferably a group in which two or more hydrogen atoms have been removed from cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane or tetracyclododecane.

When R ² is a divalent linking group containing a hetero atom, preferred examples of the linking group include —O—, —C (═O) —O—, —C (═O) —, —O—C. (═O) —O—, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group or an acyl group.
_{), - S -, - S} (= O) 2 -, - S (= O) 2 -O-, wherein -A-O-B-, a group represented by the formula - [A-C (= O ) Group represented by -O] _m- B-, etc. are mentioned. Here, A and B are each independently a divalent hydrocarbon group which may have a substituent, and m is an integer of 0 to 3.
When R ² is —NH—, H may be substituted with a substituent such as an alkyl group or an acyl group. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.
In —A—O—B— or — [A—C (═O) —O] _m —B—, A and B are each independently a divalent hydrocarbon which may have a substituent. It is a group.
Examples of the divalent hydrocarbon group which may have a substituent in A and B are the same as those described above as the “divalent hydrocarbon group which may have a substituent” in R ² . Can be mentioned.
As A, a linear aliphatic hydrocarbon group is preferable, a linear alkylene group is more preferable, a linear alkylene group having 1 to 5 carbon atoms is more preferable, and a methylene group or an ethylene group is particularly preferable. .
B is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.
In the group represented by the formula — [A—C (═O) —O] _m —B—, m is an integer of 0 to 3, preferably an integer of 0 to 2, and 0 or 1 Is more preferable and 1 is most preferable.

In formula (a0-1), R ³ is a cyclic group containing —SO ₂ — in the ring skeleton.
The cyclic group in R ³ represents a cyclic group containing a ring containing —SO ₂ — in the ring skeleton, and the ring is counted as the first ring. When the group has another ring structure, it is called a polycyclic group regardless of the structure. The cyclic group for R ³ may be a monocyclic group or a polycyclic group.
R ³ particularly preferably has a cyclic group containing —O—SO ₂ — in its ring skeleton, that is, a sulton ring.
The cyclic group for R ³ preferably has 3 to 30 carbon atoms, preferably 4 to 20 carbon atoms, more preferably 4 to 15 carbon atoms, and particularly preferably 4 to 12 carbon atoms.
However, the carbon number is the number of carbon atoms constituting the ring skeleton, and does not include the carbon number in the substituent.
The cyclic group for R ³ may be an aliphatic cyclic group or an aromatic cyclic group.
An aliphatic cyclic group is preferable.
As the aliphatic cyclic group for R ^3, a carbon atom constituting a ring skeleton of the cyclic aliphatic hydrocarbon group mentioned above is partially substituted with —SO ₂ — or —O—SO ₂ —. Is mentioned.
More specifically, for example, the monocyclic group includes a group obtained by removing one hydrogen atom from a monocycloalkane in which —CH ₂ — constituting the ring skeleton is substituted with —SO ₂ —, and the ring And a group in which one hydrogen atom is removed from a monocycloalkane in which —CH ₂ —CH ₂ — constituting R ₁ is substituted with —O—SO ₂ —. The polycyclic group includes one hydrogen atom from a polycycloalkane (bicycloalkane, tricycloalkane, tetracycloalkane, etc.) in which —CH ₂ — constituting the ring skeleton is substituted with —SO ₂ —. And a group obtained by removing one hydrogen atom from a polycycloalkane in which —CH ₂ —CH ₂ — constituting the ring is substituted with —O—SO ₂ —.

The cyclic group for R ³ may have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), —COOR ″, —OC (═O) R ″, a hydroxyalkyl group, a cyano group, and the like. Is mentioned.
The alkyl group as the substituent is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, and a hexyl group. Among these, a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable.
The alkoxy group as the substituent is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, the group couple | bonded with the oxygen atom (-O-) to the alkyl group quoted as the alkyl group as the said substituent is mentioned.
Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group for the substituent include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.
Examples of the halogenated alkyl group as the substituent include groups in which part or all of the hydrogen atoms of the alkyl group mentioned as the alkyl group as the substituent are substituted with the halogen atom. As the halogenated alkyl group, a fluorinated alkyl group is preferable, and a perfluoroalkyl group is particularly preferable.
R ″ in —COOR ″ and —OC (═O) R ″ is a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 15 carbon atoms.
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group or an ethyl group. preferable.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom Or a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorinated alkyl group More specifically, one or more hydrogen atoms are removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Groups and the like.
The hydroxyalkyl group as the substituent is preferably one having 1 to 6 carbon atoms. Specifically, at least one of the hydrogen atoms of the alkyl group mentioned as the alkyl group as the substituent is substituted with a hydroxyl group. Group.
More specifically, examples of R ³ include groups represented by the following general formulas (3-1) to (3-4).

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

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

In the general formulas (3-1) to (3-4), A ′ represents an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (—O—) or a sulfur atom (—S—), An oxygen atom or a sulfur atom.
The alkylene group having 1 to 5 carbon atoms in A ′ is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group.
When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include a group in which —O— or —S— is interposed between the terminal or carbon atoms of the alkylene group, for example, —O—CH _{2. -, - CH 2 -O-CH} 2 -, - S-CH 2 -, - CH 2 -S-CH 2 - , and the like.
A ′ is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.
a may be any of 0 to 2, and 0 is most preferable.
When a is 2, the plurality of R ⁶ may be the same or different.
The alkyl group in R ^6, an alkoxy group, a halogenated alkyl group, -COOR ", - OC (= O) R", The hydroxyalkyl groups, respectively, may have the cyclic group in ^{R 3} substituent Examples thereof include the same alkyl groups, alkoxy groups, halogenated alkyl groups, —COOR ″, —OC (═O) R ″, and hydroxyalkyl groups mentioned as groups.
Specific examples of cyclic groups represented by the general formulas (3-1) to (3-4) are shown below. In the formula, “Ac” represents an acetyl group.

Among these, R ³ is preferably a group represented by the following general formula (3-1), (3-3), or (3-4), and is represented by the following general formula (3-1). The group is particularly preferred.
Specifically as R ³ , from the group represented by any one of the chemical formulas (3-1-1), (3-1-18), (3-3-1) and (3-4-1) It is more preferable to use at least one selected from the group consisting of: a group represented by the chemical formula (3-1-1) is most preferable.

  In the present invention, the structural unit (a0) is particularly preferably a structural unit represented by the following general formula (a0-1-11).

［式中、Ｒ^１は前記と同じであり、Ｒ^２’は直鎖状または分岐鎖状のアルキレン基であり、Ａ’は前記と同じである。］

[Wherein, R ¹ is as defined above, R ² ′ is a linear or branched alkylene group, and A ′ is as defined above. ]

The linear or branched alkylene group for R ² ′ preferably has 1 to 10 carbon atoms, more preferably 1 to 8, more preferably 1 to 5, particularly preferably 1 to 3. ~ 2 is most preferred.
A ′ is preferably a methylene group, an oxygen atom (—O—) or a sulfur atom (—S—).

As the structural unit (a0), one type may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a0) in the component (A1) is determined by the MEF and the shape of the resist pattern to be formed (for example, when the resist pattern is formed using the positive resist composition containing the component (A1)). It is excellent in CDU (in-plane uniformity), LWR (line width roughness), etc. since it is a line pattern (rectangularity, hole pattern, roundness, etc.). On the other hand, it is preferably 1 to 60 mol%, more preferably 5 to 50 mol%, and still more preferably 10 to 45 mol%.

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

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

Here, the term “aliphatic branched” in the claims and the specification means having a branched structure having no aromaticity.
The structure of the “aliphatic branched acid dissociable, dissolution inhibiting group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group.
The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
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” in the structural unit (a1) may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like. Is mentioned.
The basic ring structure excluding the substituent of the “aliphatic cyclic group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated. The “aliphatic cyclic group” is preferably a polycyclic group.
Examples of the aliphatic cyclic group include 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.

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、Ｒ^１６はそれぞれ独立してアルキル基（直鎖状、分岐鎖状のいずれでもよく、好ましくは炭素数１〜５である）を示す。］

[Wherein, R ¹⁵ and R ¹⁶ each independently represents an alkyl group (which may be linear or branched, and preferably has 1 to 5 carbon atoms). ]

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

［式中、Ｒ^１’、ｎ、Ｙは上記と同様である。］

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

The alkyl group of 1 to 5 carbon atoms for Y, the same alkyl group of 1 to 5 carbon atoms of the R ¹ can be mentioned.
The aliphatic cyclic group for Y can be appropriately selected from monocyclic or polycyclic aliphatic cyclic groups conventionally proposed in a number of ArF resists and the like. 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または分岐鎖状のアルキル基または水素原子であり、Ｒ^１９は直鎖状、分岐鎖状または環状のアルキル基である。または、Ｒ^１７およびＲ^１９がそれぞれ独立に直鎖状または分岐鎖状のアルキレン基であって、Ｒ^１７の末端とＲ^１９の末端とが結合して環を形成していてもよい。］

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

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

  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. ]

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

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

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

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

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

In general formula (a1-0-1), R is the same as R ¹ in formula (a0-1).
X ¹ is not particularly limited as long as it is an acid dissociable, dissolution inhibiting group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable, dissolution inhibiting group and acetal type acid dissociable, dissolution inhibiting group. And tertiary alkyl ester type acid dissociable, dissolution inhibiting groups are preferred.

In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).
Examples of the divalent linking group for Y ² include the same groups as those described above for R ² in formula (a0-1).
Y ² is preferably the aforementioned alkylene group, divalent aliphatic cyclic group or divalent linking group containing a hetero atom. Among these, a divalent linking group containing a hetero atom is preferable, and a linear group having an oxygen atom as a hetero atom, for example, a group containing an ester bond is particularly preferable.
Among them, a group represented by the above-described —A—O—B— or —A—C (═O) —O—B— is preferable, and in particular, — (CH ₂ ) _x —C (═O) —O— ( CH _{2) y} - group represented by are preferred.
x is an integer of 1 to 5, preferably 1 or 2, and most preferably 1.
y is an integer of 1 to 5, preferably 1 or 2, and most preferably 1.

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

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

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

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

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

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
In the present invention, the structural unit represented by the following general formula (a1-0-11) as the structural unit (a1), particularly from the point that the lithography properties such as resolution and resist pattern shape are excellent, It is preferable to have at least one selected from the group consisting of a structural unit represented by (a1-0-12) and a structural unit represented by the following general formula (a1-0-2).

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基であり、Ｒ^２１はアルキル基であり、Ｒ^２２は、当該Ｒ^２２が結合した炭素原子と共に脂肪族単環式基を形成する基であり、Ｒ^２３は分岐鎖状のアルキル基であり、Ｒ^２４は、当該Ｒ^２４が結合した炭素原子と共に脂肪族多環式基を形成する基であり、Ｙ^２は２価の連結基であり、Ｘ^２は酸解離性溶解抑制基である。］

[Wherein R is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ²¹ is an alkyl group, and R ²² forms an aliphatic monocyclic group together with the carbon atom to which R ²² is bonded. R ²³ is a branched alkyl group, R ²⁴ is a group that forms an aliphatic polycyclic group together with the carbon atom to which R ²⁴ is bonded, and Y ² is a divalent linking group. X ² is an acid dissociable, dissolution inhibiting group. ]

In each formula, the description of R, Y ² and X ² is the same as described above.
In formula (a1-0-11), examples of the alkyl group for R ²¹ include the same alkyl groups as those described above for R ¹⁴ in formulas (1-1) to (1-9). Group is preferred, and ethyl group is most preferred.
R ²² is, the aliphatic monocyclic group formed together with the carbon atom to which R ²² is bonded, the same aliphatic cyclic groups as those in the tertiary alkyl ester-type acid dissociable, monocyclic The thing similar to what is a formula group is mentioned. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane is preferably a 3- to 11-membered ring, more preferably a 3- to 8-membered ring, further preferably a 4- to 6-membered ring, and particularly preferably a 5- or 6-membered ring.
In the monocycloalkane, a part of carbon atoms constituting the ring may or may not be substituted with an etheric oxygen atom (—O—).
The monocycloalkane may have a lower alkyl group, a fluorine atom or a fluorinated alkyl group as a substituent.
Examples of R ²² constituting the aliphatic monocyclic group include a linear alkylene group in which an etheric oxygen atom (—O—) may be interposed between carbon atoms.

Specific examples of the structural unit represented by the formula (a1-0-11) include structural units represented by the formulas (a1-1-16) to (a1-1-23). Among these, the following (a1-1) including structural units represented by formulas (a1-1-16) to (a1-1-17) and (a1-1-20) to (a1-1-23) The structural unit represented by -02) is preferable. Moreover, the structural unit represented by the following (a1-1-02 ′) is also preferable.
In each formula, h is preferably 1 or 2, and most preferably 2.

（式中、Ｒ、Ｒ^２１はそれぞれ前記と同じであり、ｈは１〜３の整数である。）

(Wherein R and R ²¹ are the same as defined above, and h is an integer of 1 to 3)

In the formula (a1-0-12), the branched alkyl group represented by R ^{23 is} the branched alkyl group exemplified for the alkyl group represented by R ^{14 in} the formulas (1-1) to (1-9). Examples thereof are the same as those described above, and an isopropyl group is most preferable.
R ²⁴ is, the aliphatic polycyclic group formed together with the carbon atom to which R ²⁴ is bonded, the same aliphatic cyclic groups as those in the aforementioned tertiary alkyl ester-type acid dissociable, dissolution inhibiting group, a polycyclic The thing similar to what is a formula group is mentioned.
Specific examples of the structural unit represented by the formula (a1-0-12) include structural units represented by the formulas (a1-1-26) to (a1-1-31).

Examples of the structural unit represented by the formula (a1-0-2) include the structural unit represented by the formula (a1-3) or (a1-4), particularly represented by the formula (a1-3). Are preferred.
As the structural unit represented by the formula (a1-0-2), particularly, Y ^{2 in} the formula is represented by the above-mentioned —A—O—B— or —A—C (═O) —O—B—. The group which is a group is preferable.
Preferred examples of the structural unit include a structural unit represented by the following general formula (a1-3-01); a structural unit represented by the following general formula (a1-3-02); 3-03); and the like.

（式中、Ｒ、Ｒ^１４は前記と同じであり、Ｒ^１３は水素原子またはメチル基であり、ａは１〜１０の整数である。）

(In the formula, R and R ¹⁴ are the same as above, R ¹³ is a hydrogen atom or a methyl group, and a is an integer of 1 to 10.)

（式中、Ｒ、Ｒ^１４は前記と同じであり、Ｒ^１３は水素原子またはメチル基であり、ａは１〜１０の整数であり、ｎ’は０〜３の整数である。）

(In the formula, R and R ¹⁴ are the same as above, R ¹³ is a hydrogen atom or a methyl group, a is an integer of 1 to 10, and n ′ is an integer of 0 to 3.)

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

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

In formulas (a1-3-01) to (a1-3-02), R ¹³ is preferably a hydrogen atom.
a is preferably an integer of 1 to 8, more preferably an integer of 1 to 5, and most preferably 1 or 2.
n ′ is preferably 1 or 2, and most preferably 2.
Specific examples of the structural unit represented by the formula (a1-3-01) include structural units represented by the formulas (a1-3-25) to (a1-3-26).
Specific examples of the structural unit represented by the formula (a1-3-02) include structural units represented by the formulas (a1-3-27) to (a1-3-28).

In formula (a1-3-03), examples of the divalent linking group for Y ² ′ and Y ² ″ include the same groups as those described above for Y ² in formula (a1-3).
Y ² ′ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and still more preferably a linear alkylene group. Among these, a linear alkylene group having 1 to 5 carbon atoms is preferable, and a methylene group and an ethylene group are most preferable.
Y ² ″ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and still more preferably a linear alkylene group. A linear alkylene group of 1 to 5 is preferable, and a methylene group and an ethylene group are most preferable.
Examples of the acid dissociable, dissolution inhibiting group for X ′ include the same groups as described above, and are preferably tertiary alkyl ester type acid dissociable, dissolution inhibiting groups, and (i) the monovalent aliphatic cyclic group described above. A group having a tertiary carbon atom on the ring skeleton of the group is more preferable, and among them, a group represented by the general formula (1-1) is preferable.
n is an integer of 0 to 3, and n is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 1.
As the structural unit represented by the formula (a1-3-03), a structural unit represented by the following general formula (a1-3-03-1) or (a1-3-03-2) is preferable. Among these, the structural unit represented by the formula (a1-3-03-1) is preferable, and the structural units represented by the formulas (a1-3-29) to (a1-3-30) are particularly preferable.

［式中、ＲおよびＲ^１４はそれぞれ前記と同じであり、Ｒ^２０は水素原子またはメチル基であり、ａは１〜１０の整数であり、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, R ²⁰ is a hydrogen atom or a methyl group, a is an integer of 1 to 10, b is an integer of 1 to 10, and t is 0. It is an integer of ~ 3. ]

a is preferably an integer of 1 to 5, and particularly preferably 1 or 2.
b is preferably an integer of 1 to 5, and 1 or 2 is particularly preferable.
t is preferably an integer of 1 to 3, and 1 or 2 is particularly preferable.

In the present invention, it is particularly preferable that the structural unit (a1) has at least two kinds. Since the lithography properties are improved, the structural unit (a1) contained in the component (A1) is preferably 2 to 4 types, and more preferably 2 or 3 types.
In this case, at least one of the at least two types is a structural unit represented by the general formula (a1-0-11), a structural unit represented by the general formula (a1-0-12), and the It is preferably at least one selected from the group consisting of structural units represented by general formula (a1-0-2).
In this case, the at least two kinds of structural units (a1) are structural units represented by the general formula (a1-0-11), structural units represented by the general formula (a1-0-12), and It may be comprised only from what is selected from the group which consists of a structural unit represented by general formula (a1-0-2), At least 1 sort (s) of these structural units, and a structural unit (a1) which does not correspond to these It may be a combination.

Structural unit represented by general formula (a1-0-11), structural unit represented by general formula (a1-0-12) and structural unit represented by general formula (a1-0-2) As the structural unit (a1) that can be used in combination with at least one selected from the group consisting of: -1) to (a1-1-2) and (a1-1-7) to (a1-1-15), the structural unit represented by the following general formula (a1-1-10), the above general formula Examples include the structural unit represented by (a1-2) and the structural unit represented by the general formula (a1-4).
As the structural unit represented by the general formula (a1-1-10), in particular, the following general formula (a1-1-1-) including the formula (a1-1-1) to the formula (a1-1-2). 101) is preferred.

［式中、Ｒは前記と同じであり、Ｒ^２５およびＲ^１１はそれぞれ独立に炭素数１〜５の直鎖状のアルキル基であり、Ｒ^２４は前記と同様である。］

[Wherein, R is the same as defined above, R ²⁵ and R ¹¹ each independently represent a linear alkyl group having 1 to 5 carbon atoms, and R ²⁴ is the same as defined above. ]

  In the component (A1), the proportion of the structural unit (a1) is preferably from 10 to 80 mol%, more preferably from 20 to 75 mol%, more preferably from 25 to 70 mol%, based on all the structural units constituting the component (A1). Is more preferable. By setting it to the lower limit value or more, a pattern can be easily obtained when the resist composition is used, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

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

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

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

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, and R ′ is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or carbon. An alkoxy group of 1 to 5 or —COOR ″, R ″ is a hydrogen atom or an alkyl group, R ²⁹ is a single bond or a divalent linking group, and s ″ is an integer of 0 or 1 or 2; A ″ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, and m is an integer of 0 or 1. ]

R in the general formulas (a2-1) to (a2-5) is the same as R in the structural unit (a1).
Examples of the alkyl group having 1 to 5 carbon atoms of R ′ include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group.
Examples of the alkoxy group having 1 to 5 carbon atoms of R ′ include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group.
R ′ is preferably a hydrogen atom in view of industrial availability.
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom Or a group in which one or more hydrogen atoms are removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, which may or may not be substituted with a fluorinated alkyl group Specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Etc.
A ″ is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.
R ²⁹ is a single bond or a divalent linking group. The divalent linking group is the same as the divalent linking group described for Y2 in the general formula (a1-0-2), and among them, an alkylene group and an ester bond (—C (═O) -O-) or a combination thereof is preferable. The alkylene group as the divalent linking group for R ²⁹ is more preferably a linear or branched alkylene group. Specifically, the same as the linear alkylene group and the branched alkylene group mentioned as the aliphatic hydrocarbon group for A in Y ² can be used.
s ″ is preferably an integer of 1 to 2.
Specific examples of the structural units represented by the general formulas (a2-1) to (a2-5) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

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

  The proportion of the structural unit (a2) in the component (A1) is such that the resist film formed using the positive resist composition containing the component (A1) adheres to a support such as a substrate, and the developer. From the viewpoint of excellent affinity and the like, it is preferably 1 to 50% by mole, more preferably 5 to 50% by mole, and further more preferably 10 to 45% by mole based on all structural units constituting the component (A1). preferable.

  In addition, since the component (A1) is excellent in various lithography properties, the total proportion of the structural unit (a0) and the structural unit (a2) (in the case where the structural unit (a2) is not included, the structural unit ( The proportion of a0) is preferably 25 to 85 mol%, more preferably 30 to 85 mol%, most preferably 30 to 80 mol% with respect to all structural units constituting the component (A1). preferable. By setting it as the said range, MEF, CDU, and a pattern shape will become further favorable.

(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 (A) 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 (polycyclic group). It is done. As the polycyclic group, for example, a resin for a resist composition for ArF excimer laser can be appropriately selected from among many proposed ones. The polycyclic group preferably has 7 to 30 carbon atoms.
Among them, a structural unit derived from an acrylate ester containing an aliphatic polycyclic group containing a hydroxyalkyl group in which a part of hydrogen atoms of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with a fluorine atom Is more preferable. Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. Specific examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, 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) 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) ) Is preferable.

[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 defined 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 3-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.

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a3) in the component (A1) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, based on all structural units constituting the component (A1). More preferred is ˜25 mol%.

(Other structural units)
The component (A1) is a structural unit other than the structural units (a0), (a1), (a2), and (a3) as long as the effects of the present invention are not impaired (hereinafter referred to as the structural unit (a4)). .) May be included.
The structural unit (a4) is not particularly limited as long as it is another structural unit that is not classified into the above-described structural units (a0), (a1), (a2), and (a3). For ArF excimer laser, Many things conventionally known as what is used for resist resins, such as for KrF excimer lasers (preferably for ArF excimer lasers), can be used.
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing an acid non-dissociable aliphatic polycyclic group, a structural unit derived from a styrene monomer, a vinyl naphthalene monomer, or the like. Is preferred. Examples of the polycyclic group include those exemplified in the case of the structural unit (a1), and for ArF excimer laser and KrF excimer laser (preferably for ArF excimer laser). A number of hitherto known materials can be used as the resin component of the resist composition.
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 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 those 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. ]

  When the structural unit (a4) is contained in the component (A1), the proportion of the structural unit (a4) is preferably 1 to 30 mol% with respect to the total of all the structural units constituting the component (A1). -20 mol% is more preferable.

In the present invention, the component (A1) is a copolymer having the structural units (a0) and (a1), and has (a2) and (a3) in addition to the structural units (a0) and (a1). Is preferred.
Examples of such a copolymer include a copolymer composed of the structural units (a0), (a1), and (a3), and a structural unit (a0), (a1), (a2), and (a3). A copolymer etc. can be illustrated.
In the present invention, as the component (A1), those having structural units represented by general formulas (A1-11) to (A1-14) shown below are particularly preferable. In addition, you may have multiple types about each structural unit shown to (A1-11)-(A1-14), respectively.

［式中、Ｒ、Ｒ^２’、Ｒ^１４、Ｒ^２９、Ａ’、ａ、ｂはそれぞれ前記と同じであり、複数のＲ、Ｒ^１４は同じであっても異なっていてもよく、ｃは１〜３の整数であり、ｉは１〜３の整数である。］

[Wherein, R, R ² ′, R ¹⁴ , R ²⁹ , A ′, a, b are the same as defined above, and a plurality of R, R ¹⁴ may be the same or different, and c is It is an integer of 1-3, i is an integer of 1-3. ]

In formula (A1-14), c is preferably 1 or 2, and more preferably 1.
In formulas (A1-11) to (A1-14), i is preferably 1 or 2, and more preferably 1. When i is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When i is 1, it is preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group. i is preferably 1, and a hydroxyl group bonded to the 3-position of the adamantyl group is particularly preferable.

The mass average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, preferably 1000 to 50000, more preferably 1500 to 30000, most preferably 2500 to 20000. preferable. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is above the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Moreover, dispersity (Mw / Mn) is 1.01-1.50, 1.01-1.45 are preferable and 1.01-1.40 are more preferable. 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.
The proportion of the component (A1) in the component (A) is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and still more preferably 25 to 75% by mass with respect to the total mass of the component (A).

  Component (A1) is a monomer derived from each structural unit, such as living radical polymerization using a living radical polymerization initiator such as azobisisobutyronitrile (AIBN) or dibutyl telluride, or other known living It can be obtained by a polymerization method capable of radical polymerization.

  Living radical polymerization can be performed by a conventionally known method (for example, Japanese Patent Application Laid-Open Nos. 2004-323893, 2005-126659, 2005-34409, 2006-299278, and 2008-247919). For example). For example, by reacting a monomer that induces each structural unit of the component (A1) with a compound represented by the following general formulas (V-3), (V-4), and (V-5), (A1 ) Ingredients can be produced.

［式中、Ｒ^ｐ１は炭素数１〜８のアルキル基、アリール基、置換アリール基又は芳香族ヘテロ環基であり、Ｒ^ｐ２及びＲ^ｐ３は、水素原子又は炭素数１〜８のアルキル基であり、Ｒ^ｐ４は、アリール基、置換アリール基、芳香族ヘテロ環基、アシル基、オキシカルボニル基又はシアノ基であり、Ｒ^ｐ５及びＲ^ｐ６は、同一又は異なっても良い炭素数１〜１０のアルキル基、カルボキシ置換された炭素数１〜４のアルキル基、置換基を有してもよいフェニル基であり、同じ炭素原子に結合しているＲ^ｐ５とＲ^ｐ６とで脂肪族環を形成していてもよく、Ｒ^ｐ７は、シアノ基、アセトキシ基、カルバモイル基、（炭素数１〜４のアルコキシ）カルボニル基である。 ］

[Wherein, R ^p1 represents an alkyl group having 1 to 8 carbon atoms, an aryl group, a substituted aryl group, or an aromatic heterocyclic group, and R ^p2 and R ^p3 represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. R ^p4 is an aryl group, a substituted aryl group, an aromatic heterocyclic group, an acyl group, an oxycarbonyl group, or a cyano group, and R ^p5 and R ^p6 may be the same or different and have 1 to 10 carbon atoms An alkyl group, a carboxy-substituted alkyl group having 1 to 4 carbon atoms, and a phenyl group which may have a substituent, and R ^p5 and R ^p6 bonded to the same carbon atom form an aliphatic ring. R ^p7 may be a cyano group, an acetoxy group, a carbamoyl group, or a (C 1-4 alkoxy) carbonyl group. ]

The method of reacting the monomer for deriving each structural unit of the component (A1), the compound (V-3), the compound (V-4) and the compound (V-5) is not particularly limited. For example, an inert gas Examples include a method in which a monomer that induces each structural unit of the component (A1), the compound (V-3), the compound (V-4), and the compound (V-5) are brought into contact in a substitution container.
As the compound (V-3), the compound (V-4) and the compound (V-5), commercially available products or synthesized compounds may be used.
As the compound (V-3), an organic tellurium compound can be used.
A ditelluride compound can be used as the compound (V-4).
As the compound (V-5), an azo polymerization initiator can be used.
This reaction can be performed without a solvent, but a reaction solvent may be used. Any reaction solvent may be used as long as it can dissolve the starting compound. Specific examples include tetrahydrofuran (THF), acetone, dimethylformamide (DMF), dimethylacetamide, dimethylsulfoxide (DMSO), dioxane, and the like. .
The addition amount of the compounds (V-3) to (V-5) and the addition amount of the monomer for deriving each structural unit of the component (A1) are the same as the addition amounts of the compounds (V-3) to (V-5). The monomer for deriving each structural unit of the component (A1) is preferably about 5 to 10,000 equivalents, more preferably 50 to 5000 equivalents.
Further, the ratio of the compounds (V-3) to (V-5) is not particularly limited, but the compound (V-4) is 0.1 to 10 equivalents relative to the compound (V-3), 0.1-10 equivalent is preferable for a compound (V-5).
The reaction temperature is preferably 40 to 150 ° C, more preferably 50 to 120 ° C.
The reaction time varies depending on the reactivity of the compound, reaction temperature and the like, but is usually preferably 0.5 to 96 hours, more preferably 1 to 48 hours.

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 into which a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom is introduced has reduced development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing
As the monomer for deriving each structural unit, a commercially available monomer may be used, or the monomer may be synthesized using a known method.
For example, as a monomer for deriving the structural unit (a0), a compound represented by the following general formula (I) (hereinafter referred to as compound (I)) can be mentioned.

［式（Ｉ）中、Ｒ^１〜Ｒ^３はそれぞれ前記と同じである。］

[In formula (I), R ^{1 to} R ³ are the same as defined above. ]

The method for producing such compound (I) is not particularly limited, and can be produced using a known method.
For example, in the presence of a base, a compound (X-) represented by the following general formula (X-2) is added to a solution in which the compound (X-1) represented by the following general formula (X-1) is dissolved in the reaction solvent. The compound (I) is obtained by adding and reacting 2).
Examples of the base include inorganic bases such as sodium hydride, K ₂ CO ₃ and Cs ₂ CO ₃ ; organic bases such as triethylamine, 4-dimethylaminopyridine (DMAP) and pyridine. Examples of the condensing agent include carbodiimide reagents such as ethyldiisopropylaminocarbodiimide (EDCI) hydrochloride, dicyclohexylcarboimide (DCC), diisopropylcarbodiimide, carbodiimidazole, tetraethylpyrophosphate, benzotriazole-N-hydroxytrisdimethylaminophosphonium hexa Fluorophosphide salt (Bop reagent) and the like.
Moreover, you may use an acid as needed. As the acid, those usually used in dehydration condensation and the like can be used. Specifically, inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p- Organic acids such as toluenesulfonic acid can be mentioned. These may be used alone or in combination of two or more.

  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>
(B) It does not specifically limit as a component, What has been proposed as an acid generator for chemical amplification type resists until now 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、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; among R ¹ ″ to R ³ ″ in formula (b-1), Any two may be bonded to each other to form a ring together with the sulfur atom in the formula; R ⁴ ″ may be an optionally substituted alkyl group, halogenated alkyl group, aryl group, or alkenyl group; Represents 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. 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 of R ¹ ″ to R ³ ″ are aryl groups.

The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups It may or may not be substituted with a group, a halogen atom, a hydroxyl group or the like.
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 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, ethyl group, propyl group, n-butyl group, or 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 for the hydrogen atom of the aryl group is preferably a fluorine atom.

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.

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, 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 are the same as the aryl groups of R ¹ ″ to R ³ ″.

Preferable examples of the cation moiety of the compound represented by the formula (b-1) include cation moieties represented by the following formulas (I-1-1) to (I-1-10). Among these, those having a triphenylmethane skeleton such as a cation moiety represented by formulas (I-1-1) to (I-1-8) are preferable.
In the following formulas (I-1-9) to (I-1-10), R ⁹ and R ¹⁰ are each independently a phenyl group, naphthyl group or carbon number 1 to 5 which may have a substituent. An alkyl group, an alkoxy group, and a hydroxyl group.
u is an integer of 1 to 3, and 1 or 2 is most preferable.

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%. It is preferable that it is 50 to 100%, and 100% is the most preferable. The higher the halogenation rate, the more preferable the strength of the acid.
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 as the halogen atom and alkyl group in the halogenated alkyl group in R ⁴ ″.
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 —O—C (═O) — , R ^{91 to} R ⁹³ are each independently an alkylene group.) And the like.
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 group; trimethylene group (n-propylene group) [—CH ₂ CH ₂ CH ₂ —]; alkyl such as —CH (CH ₃ ) CH ₂ CH ₂ —, —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, and in particular, —R ⁹¹ —O—, —R ⁹² —O—C (═O) — 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 a part of carbon atoms constituting the ring is substituted with the heteroatom.
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 only of 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 carbon atoms include, for example, —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- etc. are mentioned. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent that substitutes 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, heicosyl group, docosyl group and the like.
The branched saturated hydrocarbon group (alkyl group) preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, Examples include 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.

As an unsaturated hydrocarbon group, it is preferable that carbon number is 2-10, 2-5 are preferable, 2-4 are preferable, and 3 is especially preferable. Examples of the linear monovalent unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched monovalent unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group.
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 are removed from a monocycloalkane; a group in which one or more hydrogen atoms are removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
When the aliphatic cyclic group does not contain a substituent containing a hetero atom in the ring structure, the aliphatic cyclic group is preferably a polycyclic group, and has one or more hydrogen atoms from the polycycloalkane. Excluded groups are preferred, and most preferred are groups obtained by removing one or more hydrogen atoms 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).
The alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, particularly preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or 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, (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) CF2 -, - 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 _{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. Trifluoromethanesulfonate or nonafluorobutanesulfonate, triphenylsulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or nonafluorobutanesulfonate, tri (4-methylphenyl) sulfonium trifluoromethanesulfonate, heptafluoropropanesulfonate or the same Nonafluorobutanesulfonate, dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, its heptaful Lopropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of monophenyldimethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; trifluoromethanesulfonate of diphenylmonomethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate (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 heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of diphenyl (1- (4-methoxy) naphthyl) sulfonium, its heptafluoropropane Sulfonate or its nonafluorobutane sulfonate, di (1-naphthyl) phenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1-phenyltetrahydrothiophenium trifluoromethane sulfonate, its heptafluoropropane sulfonate Or nonafluorobutanesulfonate thereof; 1- (4-methylphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1- (4-ethoxynaphthalene-1- Yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonaflu 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1-phenyltetrahydrothiopyranium trifluoromethanesulfonate , Its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (4-hydroxyphenyl) tetrahydrothiopyranium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl -4-Hydroxyphenyl) tetrahydrothiopyranium trifluoromethanesulfonate, its heptafluoropropanes Honeto or nonafluorobutanesulfonate; 1- (4-methylphenyl) trifluoromethanesulfonate tetrahydrothiophenium Pila chloride, heptafluoropropane sulfonate or its nonafluorobutane sulfonate, and the like.
In addition, the anion part of these onium salts may be methanesulfonate, n-propanesulfonate, n-butanesulfonate, n-octanesulfonate, 1-adamantanesulfonate, 2-norbornanesulfonate, d-camphor-10-sulfonate, benzenesulfonate, Onium salts substituted with alkyl sulfonates such as fluorobenzene sulfonate and p-toluene sulfonate 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、ｑ_１〜ｑ_２はそれぞれ独立に１〜５の整数であり、ｑ_３は１〜１２の整数であり、ｔ_３は１〜３の整数であり、ｒ_１〜ｒ_２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、Ｒ^７は置換基であり、ｎ_１〜ｎ_５はそれぞれ独立に０または１であり、ｖ_０〜ｖ_５はそれぞれ独立に０〜３の整数であり、ｗ_１〜ｗ_５はそれぞれ独立に０〜３の整数であり、Ｑ”は前記と同じである。］

[In the formula, p is an integer of 1 to 3, q ₁ and q ₂ are each independently an integer of 1 to 5, q ₃ is an integer of 1 to 12, and t ₃ is an integer of 1 to 3. , R _{1 to} r ₂ are each independently an integer of 0 to 3, g is an integer of 1 to 20, R ⁷ is a substituent, and n _{1 to} n ₅ are each independently 0 or 1 V _{0 to} v ₅ are each independently an integer of 0 to 3, w _{1 to} w ₅ are each independently an integer of 0 to 3, and Q ″ is the same as above.]

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.
If signs placed _{^{R 7 (r 1 ~r 2,}} w 1 ~w 5) is an integer of 2 or more, a plurality of the ^{R 7} groups may be the same, respectively, be different Good.

  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) may be used.

  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 for R ³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³⁵ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³⁵ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred is the strength of the acid generated. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

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

<(F) Component> [Structural Unit (f1)]
The “base dissociable group” in the structural unit (f1) is an organic group that can be dissociated by the action of a base. Examples of the base include an alkaline developer generally used in the lithography field. That is, the “base dissociable group” is a group dissociated by the action of an alkali developer (for example, 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution (23 ° C.)).
The base dissociable group is dissociated by hydrolysis caused by the action of an alkali developer.
Therefore, a hydrophilic group is formed simultaneously with the dissociation of the base dissociable group, the hydrophilicity of the component (F) is increased, and the affinity for an alkali developer is improved.
The base dissociable group is not particularly limited as long as it is an organic group corresponding to the above definition, and may contain a fluorine atom or may not contain a fluorine atom.
In the case where a fluorine atom is not contained in a site other than the base dissociable group in the structural unit (f1), it is necessary to be a base dissociable group containing a fluorine atom. On the other hand, when a fluorine atom is contained in a site other than the base dissociable group in the structural unit (f1), it may be a base dissociable group containing a fluorine atom or a base dissociating property not containing a fluorine atom. It may be a group.
The base dissociable group containing a fluorine atom refers to a group in which part or all of the hydrogen atoms in the base dissociable group are substituted with fluorine atoms.

In the structural unit (f1), the base dissociable group preferably contains a fluorine atom. In particular, it is preferable that the fluorine atom contained in the structural unit (f1) exists only in the base dissociable group. When the base-dissociable group contains a fluorine atom, when the base-dissociable group is dissociated by the action of the alkali developer, the fluorine atom is also dissociated from the structural unit (f1), so that the affinity for the alkali developer is higher. .
Specific examples of the base dissociable group containing a fluorine atom include groups represented by the following general formulas (II-1) to (II-4). In the present invention, the base dissociable group is preferably at least one selected from the group consisting of groups represented by the following general formulas (II-1) to (II-4). A group represented by the following general formula (II-1) or (II-4) is particularly preferable because it is excellent and easy to synthesize.

［式中、Ｒ^２”はそれぞれ独立してフッ素原子を有する有機基である。］

[Wherein R ^{2 ″} are each independently an organic group having a fluorine atom.]

In formulas (II-1) to (II-4), R ^{2 ″} is an organic group having a fluorine atom. The “organic group” is a group containing at least one carbon atom.
The structure of R ^{2 ″} may be linear, branched or cyclic, and is preferably linear or branched.
In R ^{2 ″} , the organic group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, particularly preferably 1 to 10 carbon atoms, and most preferably 1 to 5 carbon atoms.
R ^{2 ″} is preferably 25% or more, more preferably 50% or more, and particularly preferably 60% or more, because the hydrophobicity of the resist film during immersion exposure is increased. The “fluorination rate” is the ratio (%) of (number of fluorine atoms) to (total number of hydrogen atoms and fluorine atoms) in the organic group.

Preferred examples of R ^{2 ″} include a fluorinated hydrocarbon group which may have a substituent.
The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, but is preferably an aliphatic hydrocarbon group.
The aliphatic hydrocarbon group is a hydrocarbon group having no aromaticity. The aliphatic hydrocarbon group may be either saturated or unsaturated, but is usually preferably saturated.
That is, R ^{2 ″} is preferably a fluorinated saturated hydrocarbon group or a fluorinated unsaturated hydrocarbon group, particularly preferably a fluorinated saturated hydrocarbon group, that is, a fluorinated alkyl group.
Examples of the fluorinated alkyl group include groups in which some or all of the hydrogen atoms of the unsubstituted alkyl group described below are substituted with fluorine atoms. The fluorinated alkyl group may be a group in which part of the hydrogen atoms of the unsubstituted alkyl group is substituted with fluorine atoms, or a group in which all of the hydrogen atoms of the unsubstituted alkyl group are substituted with fluorine atoms ( Perfluoroalkyl group).

The unsubstituted alkyl group may be linear, branched or cyclic, and may be a combination of a linear or branched alkyl group and a cyclic alkyl group.
As an unsubstituted linear alkyl group, C1-C10 is preferable and C1-C8 is more preferable. Specifically, for example, methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n- A decanyl group etc. are mentioned.
As an unsubstituted branched alkyl group, C3-C10 is preferable and C3-C8 is more preferable. As the branched alkyl group, a tertiary alkyl group is preferable.
Examples of the unsubstituted cyclic alkyl group include groups in which one hydrogen atom has been removed from a monocycloalkane or a polycycloalkane such as bicycloalkane, tricycloalkane, and tetracycloalkane. Specific examples include monocycloalkyl groups such as cyclopentyl group and cyclohexyl group; polycycloalkyl groups such as adamantyl group, norbornyl group, isobornyl group, tricyclodecanyl group, and tetracyclododecanyl group.
The combination of an unsubstituted linear or branched alkyl group and a cyclic alkyl group includes a group in which a cyclic alkyl group is bonded as a substituent to a linear or branched alkyl group, or a cyclic alkyl group And a group having a linear or branched alkyl group bonded thereto as a substituent.

  Examples of the substituent that the fluorinated hydrocarbon group may have include an alkyl group having 1 to 5 carbon atoms.

In R ^{2 ″} , the fluorinated alkyl group is preferably a linear or branched fluorinated alkyl group. Particularly, a group represented by the following general formula (III-1) or (III-2) is preferable. Among these, a group represented by the formula (III-1) is preferable.

［式（ＩＩＩ−１）中、Ｒ^４１’は無置換の炭素数１〜９のアルキレン基であり、Ｒ^４２’は炭素数１〜９のフッ素化アルキル基である。但し、Ｒ^４１’とＲ^４２’との炭素数の合計は１０以下である。また、式（ＩＩＩ−２）中、Ｒ^７１’〜Ｒ^{７３ ’}は、それぞれ独立に、炭素数１〜５の直鎖状のアルキル基であり、Ｒ^７１’〜Ｒ^{７３ ’}の少なくとも１つはフッ素原子を有するアルキル基である。］

[In the formula (III-1), R ⁴¹ ′ is an unsubstituted alkylene group having 1 to 9 carbon atoms, and R ⁴² ′ is a fluorinated alkyl group having 1 to 9 carbon atoms. However, the total number of carbon atoms of R ⁴¹ ′ and R ⁴² ′ is 10 or less. In formula (III-2), R ^{71 ′ to} R ^{73 ′} are each independently a linear alkyl group having 1 to 5 carbon atoms, and at least one of R ^{71 ′ to} R ^{73 ′} is An alkyl group having a fluorine atom. ]

In formula (III-1), the alkylene group for R ⁴¹ ′ may be linear, branched or cyclic, and is preferably linear or branched. Moreover, as for the carbon number, 1-5 are preferable.
R ⁴¹ ′ is particularly preferably a methylene group, an ethylene group or a propylene group.
R ⁴² ′ is preferably a linear or branched fluorinated alkyl group having 1 to 5 carbon atoms, and particularly preferably a perfluoroalkyl group. Of these, a trifluoromethyl group and a tetrafluoroethyl group are preferable.
In formula (III-2), the alkyl group of R ^{71 ′ to} R ^{73 ′} is preferably an ethyl group or a methyl group, and particularly preferably a methyl group. Any one of the alkyl groups of R ^{71 ′ to} R ^{73 ′} may be a fluorinated alkyl group, and all may be combined with a fluorinated alkyl group.

  As a suitable thing of a structural unit (f1), the structural unit represented by the following general formula (f1-1) or (f1-2) is mentioned, for example.

［式中、Ｒはそれぞれ独立して水素原子、炭素数１〜５のアルキル基またはハロゲン化炭素数１〜５のアルキル基であり；Ｘ_００は二価の有機基であり、Ａ_ａｒｙｌは置換基を有していてもよい二価の芳香族環式基であり、Ｘ_０１は単結合または二価の連結基であり、Ｒ^２”はそれぞれ独立してフッ素原子を有する有機基である。］

[Wherein, R is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or an alkyl group having 1 to 5 carbon atoms; X ₀₀ is a divalent organic group, and A _aryl is substituted. A divalent aromatic cyclic group which may have a group, X ₀₁ is a single bond or a divalent linking group, and R ^{2 ″} each independently represents an organic group having a fluorine atom. ]

In formula (f1-1) or (f1-2), R ^{2 ″} is the same as described above. In formula (f1-1) or (f1-2), R ^{2 ″} represents a fluorinated hydrocarbon group. Preferably, a fluorinated alkyl group is more preferable, a fluorinated alkyl group having 1 to 5 carbon atoms is more preferable, —CH ₂ —CF ₃ , —CH ₂ —CF ₂ —CF ₃ , —CH (CF ₃ ) ₂ , — CH ₂ —CF ₂ —CF ₂ —CF ₃ and —CH ₂ —CH ₂ —CF ₂ —CF ₂ —CF ₂ —CF ₃ are particularly preferred.
The alkyl group having 1 to 5 carbon atoms in R is preferably linear or branched, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl. Group, pentyl group, isopentyl group, neopentyl group and the like.
Specific examples of the halogenated alkyl group having 1 to 5 carbon atoms include groups in which some or all of the hydrogen atoms of the above-mentioned “alkyl group having 1 to 5 carbon atoms” have been substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
In the present invention, as R, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms is preferable, and a hydrogen atom or a methyl group is more preferable from the viewpoint of industrial availability. .

In the general formula _{(f1-1), X 00} is a divalent organic group.
_X00 may or may not have an acid dissociable portion. The “acid-dissociable site” refers to a site in the organic group that is dissociated by the action of an acid generated by exposure. When X ₀₀ has an acid dissociable part, it is preferable that it preferably has an acid dissociable part having a tertiary carbon atom.
X ₀₀ is preferably a hydrocarbon group which may have a substituent, a group containing a hetero atom, or the like.
The term “having a substituent” for the hydrocarbon group means that part or all of the hydrogen atoms in the hydrocarbon group are substituted with groups or atoms other than hydrogen atoms.
The hydrocarbon group 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 chain-like aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

Examples of the aliphatic hydrocarbon group containing a ring include a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), and the cyclic aliphatic hydrocarbon group described above as a chain-like aliphatic group. And a group bonded to the terminal of the aromatic hydrocarbon group or interposed in the middle of the chain-like aliphatic hydrocarbon group.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic group, a group in which two hydrogen atoms are 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).

The “heteroatom” in the divalent group containing a heteroatom is an atom other than a carbon atom and a hydrogen atom, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom.
As the divalent group containing a hetero atom, specifically, —O—, —C (═O) —, —C (═O) —O—, carbonate bond (—O—C (═O) —O -), -NH-, ^-NR04 ( ^R04 is an alkyl group)-, -NH-C (= O)-, = N-, or a combination of these groups and a divalent hydrocarbon group, etc. Is 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 general formula (f1-2), A _aryl is a divalent aromatic cyclic group which may have a substituent. Specific examples of A _aryl include a group obtained by removing two hydrogen atoms from an aromatic hydrocarbon ring which may have a substituent.
The ring skeleton of the aromatic cyclic group in A _aryl preferably has 6 to 15 carbon atoms, and examples thereof include a benzene ring, a naphthalene ring, a phenanthrene ring, and an anthracene ring. Among these, a benzene ring or a naphthalene ring is particularly preferable.
In A _aryl , examples of the substituent that the aromatic cyclic group may have include a halogen atom, an alkyl group, an alkoxy group, an alkyl group having 1 to 5 halogenated carbon atoms, and an oxygen atom (═O). Can be mentioned. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom. The substituent that the aromatic cyclic group of A _aryl may have is preferably a fluorine atom.
The aromatic cyclic group of A _aryl may have no substituent, may have a substituent, and preferably has no substituent.
In A _aryl , when the aromatic cyclic group has a substituent, the number of substituents may be one, two or more, and one or two. Is preferable, and one is more preferable.
X ₀₁ is a single bond or a divalent linking group. Examples of the divalent linking group include an alkylene group having 1 to 10 carbon atoms, —O—, —C (═O) —, —C (═O) —O—, and a carbonate bond (—O—C (═O). -O-), -NH-C (= O)-, or a combination thereof may be mentioned, and a combination of -O- and an alkylene group having 1 to 10 carbon atoms is most preferable.
Examples of the alkylene group having 1 to 10 carbon atoms include linear, branched or cyclic alkylene groups, linear or branched alkylene groups having 1 to 5 carbon atoms, and 4 to 10 carbon atoms. A cyclic alkylene group is preferred.

Among the structural units represented by the general formula (f1-1), structural units represented by the following general formulas (f1-11) to (f1-14) are exemplified.
Moreover, as a suitable unit among the structural units represented by the general formula (f1-2), structural units represented by the following general formulas (f1-21) to (f1-24) can be given.

In general formulas (f1-11) to (f1-14), (f1-21) to (f1-24), and (f1-25) to (f1-27), R and R ^{2 ″} are the same as defined above. R ^{51 to} R ⁵² are each independently an alkyl group having 1 to 10 carbon atoms; R ^{53 to} R ⁵⁴ are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; a1, a2, a3, a5, a7, a9, and a11 to a13 are each independently an integer of 1 to 5; a4, a6, a8, and a10 are each independently an integer of 0 to 5; a14 to a16 is an integer of 0 to 5; b1 to b5 are each independently 0 or 1; R ⁵ is a substituent, and e is an integer of 0 to 2.
In formulas (f1-11) to (f1-14), (f1-21) to (f1-24), and (f1-25) to (f1-27), R is preferably a hydrogen atom or a methyl group.
In formula (f1-11), a1 is preferably an integer of 1 to 3, and more preferably 1 or 2.
In formula (f1-12), a2 and a3 are each independently preferably an integer of 1 to 3, and more preferably 1 or 2.
In formula (f1-13), a4 is preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and most preferably 0 or 1.
a5 is preferably an integer of 1 to 3, and more preferably 1 or 2.
Examples of the substituent for R ⁵ include a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkyl group having 1 to 5 halogenated carbon atoms, and an oxygen atom (═O). Can be mentioned. Examples of the alkyl group having 1 to 5 carbon atoms include those similar to the alkyl group having 1 to 5 carbon atoms exemplified in the above R. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom. Examples of the alkyl group having 1 to 5 halogenated carbons include the same groups as the alkyl groups having 1 to 5 halogenated carbons exemplified above for R.
e is preferably 0 or 1, and particularly preferably 0 from an industrial viewpoint.
b2 is preferably 0.
In formula (f1-14), a6 is preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and most preferably 0 or 1.
a7 is preferably an integer of 1 to 3, and more preferably 1 or 2.
b3 is preferably 0.
R ⁵ and e are the same as defined above.

In formula (f1-21), a8 is preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and most preferably 0 or 1.
a9 is preferably an integer of 1 to 3, and more preferably 1 or 2.
b4 is preferably 0.
R ⁵ and e are the same as defined above.
In formula (f1-22), a10 is preferably an integer of 0 to 3, more preferably an integer of 0 to 2, and most preferably 0 or 1.
a11 is preferably an integer of 1 to 3, and more preferably 1 or 2.
b5 is preferably 0.
R ⁵ and e are the same as defined above.
In formula (f1-23), a12 is preferably an integer of 1 to 3, and more preferably 1 or 2.
R ⁵ and e are the same as defined above.
In formula (f1-24), a13 is preferably an integer of 1 to 3, and more preferably 1 or 2.
R ⁵ and e are the same as defined above.
In formulas (f1-25) to (f1-27), each of a14, a15, and a16 is preferably 0 to 3, more preferably 0 to 2, and most preferably 0 or 1.
R ^{51 to} R ⁵² are preferably each independently a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, and may be a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, Examples include isobutyl group, tert-butyl group, tert-amyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group, norbornyl group, isobornyl group, tricyclodecanyl group, adamantyl group, and tetracyclododecanyl group. C1-C6 is more preferable, C1-C4 is especially preferable, and a methyl group or an ethyl group is the most preferable.
R ^{53 to} R ⁵⁴ are preferably each independently a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms. The linear, branched or cyclic alkyl group having 1 to 10 carbon atoms in R ^{53 to} R ⁵⁴ is the same as R ^{51 to} R ⁵² described above.
In formulas (f1-26) to (f1-27), R ⁵ and e are the same as defined above.

  Specific examples of the structural units represented by the general formulas (f1-11) to (f1-14) and the general formulas (f1-21) to (f1-27) are shown below.

  The structural unit (f1) is selected from the group consisting of structural units represented by any one of the general formulas (f1-11) to (f1-14) and (f1-21) to (f1-24). At least one is preferred, and at least one selected from the group consisting of structural units represented by any one of the general formulas (f1-11) to (f1-13), (f1-21) and (f1-22) The seed is more preferable, and at least one selected from the group consisting of the structural units represented by the general formula (f1-11) or (f1-22) is particularly preferable.

In the component (F), as the structural unit (f1), one type may be used alone, or two or more types may be used in combination.
In the component (F), the proportion of the structural unit (f1) is preferably from 10 to 90 mol%, more preferably from 20 to 80 mol%, more preferably from 30 to 80, based on the total of all structural units constituting the component (F). Mole% is more preferable, and 40 to 80 mol% is particularly preferable. When the proportion of the structural unit (f1) is not less than the lower limit of the above range, in resist pattern formation, it is hydrophobic during immersion exposure and is hydrophilic during alkali development, reducing defects in the reattachment system, The scan followability at the time of exposure is improved. If it is not more than the upper limit value, the balance with the structural unit (f2) will be good, and defects derived from the immersion scan exposure can be suppressed.

[Structural unit (f2)]
The structural unit (f2) is represented by the following general formula (f2-1).

［式中、Ｒは水素原子、炭素数１〜５のアルキル基またはハロゲン化炭素数１〜５のアルキル基であり；Ｗは下記一般式（ｗ−１）〜（ｗ−４）のいずれかにより表される基である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or an alkyl group having 1 to 5 carbon atoms; W is any one of the following general formulas (w-1) to (w-4) It is group represented by these. ]

［式（ｗ−１）中、Ｒ^２１’は炭素数２以上のアルキル基であり、Ｒ^２２’およびＲ^２３’は相互に結合して炭素数７以上の単環式の脂肪族環式基を形成している。式（ｗ−２）中、Ｒ^２４は炭素数３以上の分岐鎖状のアルキル基であり、Ｒ^２５およびＲ^２６は相互に結合して脂肪族環式基を形成している。式（ｗ−３）中、Ｒ^２７は酸解離性溶解抑制基であり、Ｒ^２８は２価の連結基である。式（ｗ−４）中、Ｒ^２９は直鎖状もしくは分岐鎖状のアルキル基または脂肪族環式基であり、ｎは０〜３の整数であり、Ｒ^３０およびＲ^３０’はそれぞれ独立して直鎖状もしくは分岐鎖状のアルキル基または水素原子であり、Ｒ^２９およびＲ^３０が相互に結合して脂肪族環式基を形成していてもよい。］

[In formula (w-1), R ^{21 ′} is an alkyl group having 2 or more carbon atoms, and R ^{22 ′} and R ^{23 ′} are bonded to each other to form a monocyclic aliphatic cyclic group having 7 or more carbon atoms. Is forming. In the formula (w-2), R ²⁴ is a branched alkyl group having 3 or more carbon atoms, and R ²⁵ and R ²⁶ are bonded to each other to form an aliphatic cyclic group. In the formula (w-3), R ²⁷ is an acid dissociable, dissolution inhibiting group, and R ²⁸ is a divalent linking group. In the formula (w-4), R ²⁹ is a linear or branched alkyl group or an aliphatic cyclic group, n is an integer of 0 to 3, and R ³⁰ and R ³⁰ ′ are each independently A linear or branched alkyl group or a hydrogen atom, and R ²⁹ and R ³⁰ may be bonded to each other to form an aliphatic cyclic group. ]

R in the formula (f2-1) is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 halogenated carbon atoms. Examples of R include those similar to R in the formula (f1-1) or (f1-2).
W is a group represented by any one of the general formulas (w-1) to (w-4).

In formula (w-1), R ^{21 ′} is an alkyl group having 2 or more carbon atoms, and R ^{22 ′} and R ^{23 ′} are bonded to each other to form a monocyclic aliphatic cyclic group having 7 or more carbon atoms. Forming.
The alkyl group for R ^{21 ′} may be linear, branched or cyclic.
When the alkyl group is linear or branched, it preferably has 2 to 5 carbon atoms, and is ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl. Group, isopentyl group, neopentyl group and the like. Among these, an ethyl group or a propyl group is more preferable, and an ethyl group is most preferable.
When the alkyl group 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. Specific examples include a group obtained by removing one hydrogen atom from a monocycloalkane; a group obtained by removing one hydrogen atom from a polycycloalkane such as bicycloalkane, tricycloalkane, and tetracycloalkane; Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one hydrogen atom from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
R ^{21 ′} is preferably a linear or branched alkyl group.

In the formula (w-1), R ^{22 ′} and R ^{23 ′} are bonded to each other, and together with the carbon atom to which the R ^{22 ′} and R ^{23 ′} are bonded, a monocyclic aliphatic cyclic group having 7 or more carbon atoms Forming a group.
The monocyclic aliphatic cyclic group preferably has 8 or more carbon atoms. The monocyclic aliphatic cyclic group preferably has 12 or less carbon atoms, more preferably 10 or less, and even more preferably 9 or less.
The aliphatic cyclic group may be saturated or unsaturated, but is preferably saturated. Further, it may be a hydrocarbon group consisting of only carbon atoms and hydrogen atoms, and may have other atoms (hetero atoms such as oxygen atom, nitrogen atom, sulfur atom), but is a hydrocarbon group. It is preferable.
A substituent may be bonded to the aliphatic cyclic group. 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).

  Preferable specific examples of the group represented by the formula (w-1) include the following.

In the formula (w-2), R ²⁴ is a branched alkyl group having 3 or more carbon atoms, and R ²⁵ and R ²⁶ are bonded to each other to form an aliphatic cyclic group.
The alkyl group for R ²⁴ 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.

In formula (w-2), R ²⁵ and R ²⁶ are bonded to each other to form an aliphatic cyclic group together with the carbon atom to which R ²⁵ and R ²⁶ are bonded.
The aliphatic cyclic group may be monocyclic or polycyclic.
The aliphatic cyclic group may be saturated or unsaturated, but is preferably saturated. Further, it may be a hydrocarbon group consisting of only carbon atoms and hydrogen atoms, and may have other atoms (hetero atoms such as oxygen atom, nitrogen atom, sulfur atom), but is a hydrocarbon group. It is preferable.
The aliphatic cyclic group preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms.
Specifically, the aliphatic cyclic group is a group in which one hydrogen atom is removed from a monocycloalkane; one hydrogen atom is removed from a polycycloalkane such as a bicycloalkane, tricycloalkane, or tetracycloalkane. And the like. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one hydrogen atom from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
A substituent may be bonded to the aliphatic cyclic group. 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).

  Preferable specific examples of the group represented by the formula (w-2) include the following.

［式中、Ｒ^２４は前記と同じであり、ｇは０〜３の整数である。］

[Wherein, R ²⁴ is the same as defined above, and g is an integer of 0 to 3. ]

  g is preferably an integer of 1 to 3, and more preferably 1 or 2.

In the formula (w-3), R ²⁷ is an acid dissociable, dissolution inhibiting group, and R ²⁸ is a divalent linking group.
The acid dissociable, dissolution inhibiting group of R ^{27 is} an acid dissociation property that is dissociated by the action of an acid generated from the component (B) upon exposure when the component (F) is blended with the resist composition together with the component (B). In addition, before dissociation, the component (F) has an alkali dissolution inhibiting property that inhibits the solubility of the component (F) in an alkaline developer.
The acid dissociable, dissolution inhibiting group for R ²⁷ is not particularly limited, and those that have been proposed as acid dissociable, dissolution inhibiting groups for base resins for chemically amplified resists can be used. Specifically, in the aforementioned component (A), the same groups as those exemplified as the acid dissociable, dissolution inhibiting group contained in the structural unit (a1) can be mentioned.

Examples of the divalent linking group for R ²⁸ include the same groups as those described above for X ₀₀ in formula (f1-1).
In the present invention, the divalent linking group for R ²⁸ is preferably an alkylene group, a divalent aliphatic cyclic group or a divalent linking group containing a hetero atom.
When R ²⁸ is an alkylene group, it preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and 1 to 3 carbon atoms. Most preferably it is.
When R ²⁸ is a divalent aliphatic cyclic group, the “aliphatic group” in the above formula (w-2) is used except that a group in which two or more hydrogen atoms are removed is used as the aliphatic cyclic group. The thing similar to description of a "group cyclic group" can be used. The aliphatic cyclic group is particularly preferably a group in which two or more hydrogen atoms have been removed from cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane or tetracyclododecane.

When R ²⁸ is a divalent linking group containing a hetero atom, examples of the divalent linking group containing a hetero atom include —O—, —C (═O) —O—, —C (═O) —, -O-C (= O) -O-, -C (= O) -NH-, -NH- (H may be substituted with a substituent such as an alkyl group or an acyl group), -S-. _{, -S (= O) 2 -} , - S (= O) 2 -O-, wherein ^{-A 01 -O-B} 01 -, a group represented by the formula ^{- [A 01 -C (= O} ) -O ] _m -B ⁰¹ - group represented by and the like. Here, A ⁰¹ and B ⁰¹ are each independently a divalent hydrocarbon group which may have a substituent, and m is an integer of 0 to 3.
When R ²⁸ is —NH—, the substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. It is particularly preferred that
When R ²⁸ is —A ⁰¹ —O—B ⁰¹ — or — [A ⁰¹ —C (═O) —O] _m —B ⁰¹ —, A ⁰¹ and B ⁰¹ are each independently a substituent. It is a divalent hydrocarbon group that may have.
m is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 1.

The hydrocarbon group for A ⁰¹ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group for A ⁰¹ may be saturated or unsaturated, and is usually preferably saturated.
More specifically, examples of the aliphatic hydrocarbon group for A ⁰¹ 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” in A ⁰¹ preferably has 1 to 10 carbon atoms, more preferably 1 to 8, more preferably 1 to 5, and more preferably 1 or 2 Particularly preferred.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable, and specifically, a methylene group, 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.
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 -, - 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 - , etc. An alkyl trimethylene group; —CH (CH ₃ ) CH ₂ CH ₂ CH ₂ —, —CH _{2 CH (CH 3) CH 2} CH 2 - alkyl alkylene group such as an alkyl tetramethylene group such like. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.
The chain-like aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

As the “aliphatic hydrocarbon group including a ring in the structure” in A ⁰¹ , a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), the cyclic aliphatic hydrocarbon Examples thereof include a group in which the group is bonded to the terminal of the chain aliphatic hydrocarbon group described above 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 are 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).

As A ⁰¹ , a linear aliphatic hydrocarbon group is preferable, a linear alkylene group is more preferable, a linear alkylene group having 1 to 5 carbon atoms is further preferable, and a methylene group or an ethylene group is particularly preferable. Preferably, an ethylene group is most preferable.

Examples of the hydrocarbon group for B ⁰¹ include the same divalent hydrocarbon groups as those described for A ⁰¹ .
B ⁰¹ is preferably a linear or branched aliphatic hydrocarbon group, particularly preferably a methylene group, an ethylene group or an alkylmethylene group.
The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.

In the group represented by the formula — [A ⁰¹ —C (═O) —O] _m —B ⁰¹ —, m is an integer of 0 to 3, preferably an integer of 0 to 2, Or 1 is more preferable and 1 is most preferable.

In the present invention, the divalent linking group for R ²⁸ is preferably a divalent group containing a hetero atom, particularly preferably a linear group having an oxygen atom as a hetero atom, such as a group containing an ester bond.
Among them, a group represented by the above-described —A ⁰¹ —O—B— or —A ⁰¹ —C (═O) —O—B ⁰¹ — is preferable, and in particular, — (CH ₂ ) _a —C (═O) — A group represented by O— (CH ₂ ) _b — is preferable.
a is an integer of 1 to 5, preferably 1 or 2, and most preferably 2.
b is an integer of 1 to 5, preferably 1 or 2, and most preferably 1.

In formula (w-4), R ^{29 ′} represents a linear or branched alkyl group or an aliphatic cyclic group.
When R ^{29 ′} is linear or branched, it preferably has 1 to 15 carbon atoms, more preferably 1 to 5, more preferably an ethyl group or a methyl group, and most preferably an ethyl group. .
When R ^{29 ′} is an aliphatic cyclic group, the aliphatic cyclic group is appropriately selected from monocyclic or polycyclic aliphatic cyclic groups that have been proposed in large numbers in ArF resists and the like. Examples thereof include those similar to the above “aliphatic cyclic group”.
The aliphatic cyclic group for R ^{29 ′} preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group, are included. Examples include a group excluding a hydrogen atom. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.

In formula (w-4), n is an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
R ³⁰ and R ³⁰ ′ are each independently a linear or branched alkyl group or a hydrogen atom.
The linear or branched alkyl group for R ³⁰ and R ³⁰ ′ is preferably an alkyl group having 1 to 5 carbon atoms. As this C1-C5 alkyl group, the same thing as the C1-C5 alkyl group of said R is mentioned, A methyl group or an ethyl group is preferable, and a methyl group is the most preferable.
In the present invention, it is preferable that at least one of R ³⁰ and R ³⁰ ′ is a hydrogen atom.

In the formula (w-4), R ^{29 ′} and R ³⁰ may be bonded to each other to form an aliphatic cyclic group.
In this case, an aliphatic cyclic group is formed by R ^{29 ′} , R ³⁰ , —O— (CH ₂ ) _n —, and the carbon atom to which R ³⁰ is bonded. As this aliphatic cyclic group, a 4-7 membered ring is preferable and a 4-6 membered ring is more preferable. Specific examples of the aliphatic cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

  Preferable specific examples of the group represented by the formula (w-4) include groups represented by the following formulas (w-4-1) to (w-4-12).

［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 component (F), as the structural unit (f2), one type may be used alone, or two or more types may be used in combination.
In the component (F), the proportion of the structural unit (f2) is preferably from 5 to 80 mol%, more preferably from 10 to 60 mol%, more preferably from 15 to 50, based on the total of all structural units constituting the component (F). More preferably, mol% is preferable, and 20-40 mol% is especially preferable. When the proportion of the structural unit (f2) is equal to or higher than the lower limit of the above range, the resist pattern is more hydrophobic in immersion exposure and more hydrophilic in exposure and PEB. become. In addition, the bridge defect can be suppressed in the line and space pattern, and the defective opening defect can be suppressed in the contact hole pattern. In addition, the proportion of hydrocarbon groups is improved, and scan followability is improved. When the amount is not more than the upper limit, the balance with the structural unit (f1) becomes good, and the water repellency effect is improved.

[Other structural units]
The component (F) may have a structural unit other than the structural unit (f1) and the structural unit (f2) (hereinafter referred to as the structural unit (f3)) as long as the effects of the present invention are not impaired.
The structural unit (f3) is not particularly limited as long as it is derived from a compound that can be copolymerized with the compound that derives the structural unit (f1) and the compound that derives the structural unit (f2). Examples of such a structural unit include those conventionally proposed as a structural unit of a base resin for a chemically amplified resist (for example, the structural units (a1) to (a3) and (a6) described above).

In the present invention, the component (F) is preferably a copolymer having the structural unit (f1) and the structural unit (f2). Examples of the copolymer include a copolymer composed only of the structural unit (f1) and the structural unit (f2); a copolymer composed of the structural unit (f1), the structural unit (f2), and the structural unit (f3). It is done.
In the present invention, the component (F) is preferably a copolymer composed of the structural unit (f1) and the structural unit (f2).

The weight average molecular weight (Mw) of the component (F) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 2000 to 50000, more preferably 3000 to 30000, and 4000 to 25000. Most preferred. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is above the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
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.

The component (F) is a monomer derived from each structural unit constituting the component (F), such as azobisisobutyronitrile (AIBN), dimethyl-2,2′-azobis (2-methylpropionate). It can be obtained by polymerizing by a known radical polymerization using a radical polymerization initiator such as (V-601).
As the monomer for deriving the structural unit (f2), CH ₂ ═C (R) —C (═O) —OW [wherein R and W are the same as defined above. And a commercially available compound can be used as such a compound.
Examples of the monomer for deriving the structural unit (f1) include compounds in which a base dissociable group and a polymerizable group are bonded via a divalent linking group.
The “polymerizable group” is a group that allows the compound having the polymerizable group to be polymerized by radical polymerization or the like, and examples thereof include a group having an ethylenic double bond. Examples of the group having an ethylenically unsaturated double bond include a group represented by CH ₂ ═CR— (wherein R is the same as described above).
Examples of the divalent linking _{group, -A} aryl _{-X 01} - _(wherein A _{aryl, X 01} are the same as defined above.), - C (= O ) -O-X 00 - ( wherein, X ₀₀ is the same as defined above).

  For example, as a monomer for deriving the structural unit represented by the general formula (f1-1) and a monomer for deriving the structural unit represented by the formula (f1-2), respectively, And a fluorine-containing compound represented by the following general formula (f0-2).

［式中、Ｒ、Ｘ_００、Ａ_ａｒｙｌ、Ｘ_０１およびＲ^２”はそれぞれ前記と同じである。］

[Wherein, R, X ₀₀ , A _aryl , X ₀₁ and R ^{2 ″} are the same as defined above.]

The fluorine-containing compound represented by formula (f0-1) or (f0-2) (hereinafter referred to as fluorine-containing compound (F0)) is, for example, the following general formula (f0-1-0) or (f0-2). R ^{2 ″} [R ^{2 ″} is the same as the above in the carboxy group of the compound represented by (−0) (hereinafter collectively referred to as the compound (V-1)). ] (Replace the hydrogen atom at the terminal of the carboxy group with R ^{2 ″} ).
Introduction of R ^{2 ″} can be carried out using a conventionally known method. For example, compound (V-1) and compound (V-2) represented by the following general formula (V-2) By reacting, the fluorine-containing compound (F0) can be produced.

［式中、Ｒ、Ｘ_００、Ａ_ａｒｙｌ、Ｘ_０１、およびＲ^２”はそれぞれ前記と同じである。］

[Wherein R, X ₀₀ , A _aryl , X ₀₁ , and R ^{2 ″} are the same as defined above.]

The method for reacting compound (V-1) and compound (V-2) is not particularly limited. For example, compound (V-1) and compound (V-2) are reacted in the presence of a base in a reaction solvent. ).
As compound (V-1) and compound (V-2), commercially available products may be used, or synthesized products may be used.
As the compound (V-1), for example, a low molecular weight compound derived from an acrylate ester such as carboxyalkyl (meth) acrylate and succinic acid mono ((meth) acryloyloxyalkyl); a structure derived from an acrylate ester A polymer compound having a unit can be used.
As the compound (V-2), for example, a fluorinated alkyl alcohol can be used.
Any reaction solvent may be used as long as it can dissolve the starting compounds (I) and (II). Specifically, tetrahydrofuran (THF), acetone, dimethylformamide (DMF), dimethylacetamide, dimethylsulfoxide ( DMSO), acetonitrile and the like.
Examples of the base include organic bases such as triethylamine, 4-dimethylaminopyridine (DMAP) and pyridine; inorganic bases such as sodium hydride, K ₂ CO ₃ and Cs ₂ CO ₃ .
Examples of the condensing agent include carbodiimide reagents such as ethyldiisopropylaminocarbodiimide (EDCI) hydrochloride, dicyclohexylcarboimide (DCC), diisopropylcarbodiimide, carbodiimidazole, tetraethylpyrophosphate, benzotriazole-N-hydroxytrisdimethylaminophosphonium hexa Fluorophosphide salt (Bop reagent) and the like.
Moreover, you may use an acid as needed. As the acid, those usually used in dehydration condensation and the like can be used. Specifically, inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p- Organic acids such as toluenesulfonic acid can be mentioned. These may be used alone or in combination of two or more.
About 1-3 equivalent is preferable with respect to compound (V-1), and, as for the addition amount of a compound (V-2), 1-2 equivalent is more preferable.
The reaction temperature is preferably -20 to 40 ° C, more preferably 0 to 30 ° C.
Although reaction time changes also with the reactivity, reaction temperature, etc. of a compound (V-1) and a compound (V-2), 30-480 minutes are preferable normally and 60-360 minutes are more preferable.

  In the present invention, the content of the component (F) is preferably 0.1 to 50 parts by weight, more preferably 0.1 to 40 parts by weight, and 0.5 to 30 parts by weight with respect to 100 parts by weight of the component (A). Is particularly preferable, and 0.5 to 15 parts by mass is most preferable. By setting it to be equal to or more than the lower limit of the above range, the hydrophobicity of the resist film formed using the positive resist composition for immersion exposure is improved, and the hydrophobicity suitable for immersion exposure is obtained. . When it is at most the upper limit value, the lithography properties are improved.

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

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

The positive resist composition of the present invention and the component (A) blended in the positive resist composition are novel ones not conventionally known.
Moreover, according to the positive resist composition of the present invention, a resist film can be formed on a support such as a substrate with good adhesion. Moreover, the positive resist composition of the present invention has good lithography properties such as sensitivity, depth of focus (DOF), exposure margin (EL) and the like. Further, a resist pattern can be formed with excellent mask reproducibility (for example, mask error factor (MEF)), and the formed resist pattern shape (for example, the roundness of the hole when the hole pattern is formed), CDU ( In-plane uniformity of pattern dimensions), LWR (line width roughness), etc. are also good. EL is a range of exposure that can form a resist pattern with a dimension within which the deviation from the target dimension is within a predetermined range when the exposure is changed, that is, an exposure that provides a resist pattern that is faithful to the mask pattern. The larger the EL margin value, the smaller the change amount of the pattern size accompanying the change in the exposure amount, and the better the process margin. DOF is a resist pattern that can form a resist pattern with a dimension in which the deviation from the target dimension is within a predetermined range when the focus is shifted up and down at the same exposure amount, that is, a resist faithful to the mask pattern. This is the range where the pattern can be obtained, and the larger the value, the better. LWR is a phenomenon in which the line width of a line pattern becomes non-uniform when a resist pattern is formed using a resist composition, and the improvement becomes more important as the pattern becomes finer. Yes.
The reason why the above effect is obtained is not clear, but as a factor, the structural unit (a0-1) has a cyclic group containing —SO ₂ —, which is a polar group, at the end of a relatively long side chain. As a result, the distribution of the component (B) becomes uniform, and it is considered that the lithography characteristics are improved.
In the present invention, the resist pattern shape and CDU can be particularly improved among the lithography properties by using a polymer compound having a low molecular weight dispersion.
The reason why the above effect is obtained is not clear, but as a factor, by using a polymer compound having a low molecular weight dispersity, the reactivity of the side chain protecting group is non-uniform, the solubility non-uniform due to the molecular weight difference, This is thought to be due to improvements in thermal resistance and non-uniformity of acid diffusion.

≪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, preferably at a temperature of 80 to 150 ° C., preferably A resist film is formed by applying for 60 to 90 seconds. For example, an exposure apparatus such as an ArF exposure apparatus, an electron beam drawing apparatus, or an EUV exposure apparatus is used for selective exposure by exposure through a mask pattern or drawing by direct irradiation of an electron beam without using a mask pattern. Thereafter, PEB (post-exposure heating) is applied for 40 to 120 seconds, preferably 60 to 90 seconds, under a temperature condition of 80 to 150 ° C. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide (TMAH), preferably rinsed with pure water and dried. In some cases, a baking process (post-bake) may be performed after the development process. In this way, a resist pattern faithful to the mask pattern can be obtained.

The support is not particularly limited, and a conventionally known one can be used, and examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
Further, the support may be a substrate in which an inorganic and / or organic film is provided on the above-described substrate. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include an organic antireflection film (organic BARC).
The wavelength used for the exposure is not particularly limited, and radiation such as ArF excimer laser, KrF excimer laser, F2 excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. Can be used. The resist composition is effective for KrF excimer laser, ArF excimer laser, EB or EUV, particularly ArF excimer laser.

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.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.
In this example, the unit represented by the chemical formula (1) is referred to as “compound (1)”, and the same applies to compounds represented by other formulas.

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

[Monomer Synthesis Example 2 (Synthesis of Compound (2))]
The compound (2) used in the polymer synthesis example described later was synthesized by the following procedure.
A 2 L three-necked flask equipped with a thermometer, a condenser tube 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.
1H-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).
13C-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 stirring device. , 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.
1H-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).
13C-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%).

[Polymer synthesis example 1]
In a nitrogen-substituted glove box, 1.454 g of ethyl-2-methyl-2-butylterranyl-propionate, 0.896 g of dibutyl ditelluride, 0.398 g of azobisisobutyronitrile, 11.14 g of compound (1) Compound (2) 6.17 g, Compound (3) 58.53 g, Compound (4) 4.16 g, 1,4-dioxane 97.78 g were charged in a reaction vessel, and polymerization reaction was carried out at 65 ° C. for 24 hours. .
Thereafter, 88.90 g of 1,4-dioxane was added, and while the reaction solution was heated with stirring and maintained at 80 ° C., a mixed solution of 17.60 g of 1,4-dioxane and 8.80 g of 30% aqueous hydrogen peroxide solution Was added dropwise over 1 hour. After completion of the dropping, stirring was continued at 80 ° C. for 12 hours.
After cooling, the reaction solution is diluted with 364 g of ethyl acetate, the organic layer is washed with 222 g of 3% oxalic acid in a separatory funnel, and then washed four times with 222 g of ion-exchanged water, for a total of 888 g of ion-exchanged water. Was washed. The organic layer was poured into 4000 g of hexane solution, the resulting precipitate was filtered off, and the recovered precipitate was dried under reduced pressure to obtain 40.0 g of the desired resin. As a result of GPC analysis of the obtained polymer, it was Mn = 5645 and Mw / Mn = 1.24.
As a result of analysis by C-NMR, the composition ratio of the polymer (ratio (molar ratio) of each structural unit in the structural formula) was l: m: n: o = 22: 9: 59: 10.

[Ｍｗ＝７，０００、Mw／Mn＝１．２４、ｌ／ｍ／ｎ／ｏ＝２２／９／５９／１０]

[Mw = 7,000, Mw / Mn = 1.24, l / m / n / o = 22/9/59/10]

[Polymer synthesis examples 2 to 4]
With reference to the description in Synthesis Example 1, the polymer compounds 2 to 4 were synthesized by changing the monomer type, the charging ratio, and the amount of the polymerization initiator used.

［Ｍｗ＝７，２００、Ｍｗ／Ｍｎ＝１．３７、ｌ／ｍ／ｎ／ｏ／ｐ＝２９／１０／４１／１０／１０］

[Mw = 7,200, Mw / Mn = 1.37, 1 / m / n / o / p = 29/10/41/10/10]

［Ｍｗ８，１００、Ｍｗ／Ｍｎ＝１．２８、ｌ／ｍ／ｎ＝３７／３８／２５］

[Mw 8,100, Mw / Mn = 1.28, 1 / m / n = 37/38/25]

［Ｍｗ７，５００、Ｍｗ／Ｍｎ＝１．３８、ｌ／ｍ／ｎ／ｏ／ｐ＝３６／２５／１８／１６／５］

[Mw 7,500, Mw / Mn = 1.38, 1 / m / n / o / p = 36/25/18/16/5]

[Synthesis example of comparative polymer compound]
Comparative polymer compound 1 was synthesized as follows.
In a separable flask connected with a thermometer, a reflux tube, and a nitrogen introduction tube, 32.32 g (102.29 mmol) of compound (1), 11.93 g (34.10 mmol) of compound (2), 8.05 g (34 .10 mmol) of compound (4) was dissolved in 106.77 g of methyl ethyl ketone (MEK). To this solution, 17.3 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved. 67.00 g (255.73 mmol) of the compound (3) was dissolved in 67.00 g of MEK and heated to 80 ° C., and the solution was added dropwise over 3 hours in a nitrogen atmosphere. After completion of dropping, the reaction solution was heated and stirred for 2 hours, and then the reaction solution was cooled to room temperature. The obtained reaction polymerization solution was dropped into a large amount of n-heptane, and the polymer was precipitated. The precipitated white powder was filtered, washed with n-heptane, isopropyl alcohol and methanol in this order and dried. As a result, 65 g of the target polymer compound 1 was obtained.
With respect to this comparative polymer compound 1, the standard polystyrene equivalent weight average molecular weight (Mw) determined by GPC measurement was 7,300, and the molecular weight dispersity (Mw / Mn) was 1.65. 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 — 13C-NMR) is 1 / m / n / o = 35/11 / 43/12.

[Mｗ＝７３００、Mw／Mn＝１．６５、ｌ／ｍ／ｎ／ｏ＝３５/１１/４３/１２]

[Mw = 7300, Mw / Mn = 1.65, l / m / n / o = 35/11/43/12]

  With reference to the synthesis of the comparative polymer compound 1 described above, the comparative polymer compound 2 was synthesized by changing the monomer type, the charging ratio, and the amount of the polymerization initiator used.

［Ｍｗ＝７，１００、Ｍｗ／Ｍｎ＝１．６６、ｌ／ｍ／ｎ／ｏ／ｐ＝２７／１０／３９／１２／１０］

[Mw = 7,100, Mw / Mn = 1.66, 1 / m / n / o / p = 27/10/39/12/10]

[Examples 1-4, Reference Examples 1-2]
Each component shown in Table 1 was mixed and dissolved to prepare a positive resist composition.

In Table 1, the numerical values in [] indicate the blending amount (parts by mass). Moreover, the symbol in Table 1 shows the following, respectively.
(A) -1: The polymer compound 1.
(A) -2: The polymer compound 2.
(A) -3: The polymer compound 3.
(A) -4: The polymer compound 4.
(A) -5: Comparative polymer compound 1 described above.
(A) -6: Comparative polymer compound 2 described above.
(B) -1: a compound represented by the following chemical formula (B) -1.
(D) -1: tri-n-pentylamine.
(E) -1: salicylic acid.
(F) -1: A compound represented by the following chemical formula (F) -1.
(S) -1: PGMEA / PGME = 6/4 (mass ratio) mixed solvent.

［Ｍｗ＝１３，８００、Ｍｗ／Ｍｎ＝１．５０、ｆ_１／ｆ_２＝７７．６／２２．４（モル比）］

_{[Mw = 13,800, Mw / Mn} = 1.50, f 1 / f 2 = 77.6 / 22.4 ( molar ratio)]

Using the obtained resist composition, a resist pattern was formed by the following procedure, and the lithography physical properties were evaluated.
[Resist pattern formation]
An organic antireflection film composition “ARC29A” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto a 12-inch silicon wafer using a spinner and baked on a hot plate at 205 ° C. for 60 seconds to be dried. Thereby, an organic antireflection film having a film thickness of 89 nm was formed. The resist composition prepared above is applied onto the antireflection film using a spinner, prebaked (PAB) at 110 ° C. for 60 seconds on a hot plate, and dried to obtain a film thickness. A 100 nm resist film was formed.
Next, an ArF immersion exposure apparatus NSR-S609B (manufactured by Nikon; NA (numerical aperture) = 1.07, σ0.97, immersion medium: water) is applied to the resist film through a hole pattern mask. On the other hand, ArF excimer laser (193 nm) was selectively irradiated.
Thereafter, PEB treatment was performed at 100 ° C. for 60 seconds, and further developed at 23 ° C. with a 2.38 mass% TMAH aqueous solution NMD-3 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) for 34.2 seconds. Water rinsing was performed using water, and post-baking (PDB) treatment was performed at 100 ° C. for 45 seconds.
As a result, in each example, a CH pattern (hereinafter, referred to as a dense CH pattern) having a hole diameter of 90 nm and a pitch of 140 nm was formed in the resist film. The optimum exposure dose Eop (mJ / cm ² ; sensitivity) at that time was determined. The results are shown in Table 2.
Next, a CH pattern having a hole diameter of 90 nm and a pitch of 540 nm (hereinafter referred to as a sparse CH pattern) is formed in the same manner as the formation of the CH pattern except that the mask is changed at the optimum exposure amount Eop at which the dense CH pattern is formed. Formed).

[CDU (Diameter Uniformity) Evaluation]
About the formed CH pattern, the diameter (CD) of 27 holes in each CH pattern was measured and evaluated according to the following criteria. The results are shown in Table 2.
○: Diameter uniformity is high.
Δ: Diameter uniformity is low.

[Roundness evaluation]
The hole shape in each CH pattern was observed with a length measurement SEM (manufactured by Hitachi, Ltd., product name: S-9220) and evaluated according to the following criteria. The results are shown in Table 2.
○: High roundness (no irregularities are seen on the circumference of the hole pattern observed from above, and it is a very good shape).
(Triangle | delta): A roundness is low (a lot of things in which a certain unevenness | corrugation is seen in the circumference part of the hole pattern observed from the sky as a whole).

  From the said result, it has confirmed that the resist composition of Examples 1-4 which concerns on this invention had a favorable shape and the lithography characteristic compared with the reference examples 1-2.

Claims (16)

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, wherein the base component (A) is a polymer compound having a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group ( A positive resist composition containing A1) and having a molecular weight dispersity (Mw / Mn) of the substrate component (A) of 1.01-1.50.

[Wherein, R ¹ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ² is a divalent linking group, and R ³ is a ring skeleton thereof. It is a cyclic group containing —SO ₂ — therein. ] The positive resist composition according to claim 1, wherein R ³ is a cyclic group containing —O—SO ₂ — in the ring skeleton. The positive resist composition according to claim 2, wherein R ³ is represented by the following general formula (3-1).

[Wherein, A ′ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, a is an integer of 0 to 2, and R ⁶ is an alkyl group. An alkoxy group, a halogenated alkyl group, a hydroxyl group, —COOR ″, —OC (═O) R ″, a hydroxyalkyl group or a cyano group, and R ″ is a hydrogen atom or an alkyl group.]   The positive resist composition according to claim 1, wherein the polymer compound (A1) has at least two types of the structural unit (a1). The polymer compound (A1) is a structural unit represented by the following general formula (a1-0-11) or a structural unit represented by the following general formula (a1-0-12) as the structural unit (a1). The positive resist composition according to claim 1, which has at least one selected from the group consisting of structural units represented by the following general formula (a1-0-2):

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ²¹ is an alkyl group, and R ²² is a carbon to which R ²² is bonded. A group that forms an aliphatic monocyclic group together with an atom, R ²³ is a branched alkyl group, and R ²⁴ is a group that forms an aliphatic polycyclic group together with the carbon atom to which R ²⁴ is bonded. Y ² is a divalent linking group, and X ² is an acid dissociable, dissolution inhibiting group. ]   The positive resist composition according to claim 1, wherein the polymer compound (A1) further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group. .   The positive type according to any one of claims 1 to 6, wherein the polymer compound (A1) further has a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group. Resist composition.   The positive resist composition as described in any one of Claims 1-7 containing a nitrogen-containing organic compound (D).   A step of forming a resist film on a support using the positive resist composition according to claim 1, a step of exposing the resist film, and an alkali developing of the resist film to form a resist A resist pattern forming method including a step of forming a pattern. It has a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group, and has a molecular weight dispersity (Mw / Mn ) Is a polymer compound of 1.01-1.50.

[Wherein, R ¹ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ² is a divalent linking group, and R ³ is a ring skeleton thereof. It is a cyclic group containing —SO ₂ — therein. ] The polymer compound according to claim 10, wherein R ³ is a cyclic group containing —O—SO ₂ — in the ring skeleton. The polymer compound according to claim 11, wherein R ³ is represented by the following general formula (3-1).

[Wherein, A ′ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, a is an integer of 0 to 2, and R ⁶ is an alkyl group. An alkoxy group, a halogenated alkyl group, a hydroxyl group, —COOR ″, —OC (═O) R ″, a hydroxyalkyl group or a cyano group, and R ″ is a hydrogen atom or an alkyl group.]   The polymer compound according to any one of claims 10 to 12, which has at least two kinds of the structural unit (a1). As the structural unit (a1), structural units represented by general formula (a1-0-11) shown below, structural units represented by general formula (a1-0-12) shown below, and general formula (a1-0-) shown below. The polymer compound according to any one of claims 10 to 13, which has at least one selected from the group consisting of structural units represented by 2).

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ²¹ is an alkyl group, and R ²² is a carbon to which R ²² is bonded. A group that forms an aliphatic monocyclic group together with an atom, R ²³ is a branched alkyl group, and R ²⁴ is a group that forms an aliphatic polycyclic group together with the carbon atom to which R ²⁴ is bonded. Y ² is a divalent linking group, and X ² is an acid dissociable, dissolution inhibiting group. ]   Furthermore, the high molecular compound as described in any one of Claims 10-14 which has the structural unit (a2) induced | guided | derived from the acrylate ester containing a lactone containing cyclic group.   Furthermore, the high molecular compound as described in any one of Claims 10-15 which has a structural unit (a3) induced | guided | derived from the acrylate ester containing a polar group containing aliphatic hydrocarbon group.