JP5285882B2 - POLYMER COMPOUND, POSITIVE RESIST COMPOSITION AND METHOD FOR FORMING RESIST PATTERN - Google Patents

Description

  The present invention relates to a novel polymer compound that can be used as a 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 been rapidly progressing due to advances in lithography technology.
As a technique for miniaturization, the wavelength of an exposure light source is generally shortened. Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but at present, mass production of semiconductor elements using a KrF excimer laser or an ArF excimer laser has started. In addition, studies have been made on F ₂ excimer lasers, electron beams, EUV (extreme ultraviolet rays), X-rays, and the like having shorter wavelengths than these excimer lasers.

Resist materials are required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing a pattern with fine dimensions.
As a resist material satisfying 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 forming the resist pattern, 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. And the exposed area becomes soluble in an alkaline developer.

Currently, as a base resin of a chemically amplified resist used in ArF excimer laser lithography and the like, a resin having a structural unit derived from (meth) acrylic acid ester in the main chain because of its excellent transparency near 193 nm ( Acrylic resin) is the mainstream (see, for example, Patent Document 1). The acrylic resin is derived from a (meth) acrylic acid ester having an aliphatic polycyclic group such as an adamantane skeleton in the ester portion because it is excellent in transparency to 193 nm light, resistance to dry etching, and the like. Those having units are common.
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 a positive type, in addition to a structural unit having an acid dissociable, dissolution inhibiting group that is dissociated by the action of an acid generated from an acid generator, a structural unit having a polar group such as a hydroxyl group, or a structure having a lactone structure Those including units are used. In particular, a structural unit having a polar group is widely used because it increases the affinity with an alkali developer and contributes to an improvement in resolution. For example, in the case of an acrylic resin, 3-hydroxyadamantyl (meth) acrylate is used. The structural unit derived from is widely used.
“(Meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position. “(Meth) acrylate ester means one or both of an acrylate ester having a hydrogen atom bonded to the α-position and a methacrylate ester having a methyl group bonded to the α-position.“ (Meth) acrylate ” , One or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position.
JP 2003-241385 A

In the future, as further advancement of lithography technology and expansion of application fields are expected, there is an increasing demand for new materials excellent in various lithography properties. For example, since the resist pattern shape affects the formation of fine semiconductor elements and the like, further improvements are required.
The present invention has been made in view of the above circumstances, and is 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 the positive resist composition. An object of the present invention is to provide a method of forming a resist pattern using a mold 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 includes a structural unit (a1 ′) represented by the following general formula (a1′-1) and a structural unit (a3 ′) represented by the following general formula (a3′-1). ) (Hereinafter referred to as polymer compound (A1)).

［式（ａ１’−１）中、Ｒ^１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、ＡおよびＢは、それぞれ独立に、置換基を有していてもよい２価の炭化水素基であり、ｎ_１は０または１であり、Ｒ^２は酸解離性溶解抑制基である。］
［式（ａ３’−１）中、Ｒ^３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^４はアルキレン基であり、ｎ_４は０または１であり、ｎ_５は０〜４の整数であり、ｎ_６は０または１であり、ｎ_５＋ｎ_６＝１〜４の整数であり、Ｒ_５およびＲ_６は、それぞれ独立に、親水基含有置換基または非親水基含有置換基であって、Ｒ_５およびＲ_６のうち少なくとも１つは親水基含有置換基である。ただし、前記親水基含有置換基が水酸基である場合を除く。］

[In formula (a1′-1), R ¹ is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and A and B are each independently a divalent carbon atom which may have a substituent. A hydrogen group, n ₁ is 0 or 1, and R ² is an acid dissociable, dissolution inhibiting group. ]
[In Formula (a3′-1), R ³ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ⁴ represents an alkylene group, n ₄ represents 0 or 1, and n ₅ represents 0 to 0. 4, n ₆ is 0 or 1, n ₅ + n ₆ = 1 to 4, and R ₅ and R ₆ are each independently a hydrophilic group-containing substituent or a non-hydrophilic group-containing substituent. And at least one of R ₅ and R ₆ is a hydrophilic group-containing substituent. However, the case where the hydrophilic group-containing substituent is a hydroxyl group is excluded. ]

The second aspect of the present invention is 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. A thing,
The base component (A) includes a structural unit (a1 ′) represented by the following general formula (a1′-1) and a structural unit (a3 ′) represented by the following general formula (a3′-1). A positive resist composition comprising a polymer compound (A1) having

［式（ａ１’−１）中、Ｒ^１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、ＡおよびＢは、それぞれ独立に、置換基を有していてもよい２価の炭化水素基であり、ｎ_１は０または１であり、Ｒ^２は酸解離性溶解抑制基である。］
［式（ａ３’−１）中、Ｒ^３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^４はアルキレン基であり、ｎ_４は０または１であり、ｎ_５は０〜４の整数であり、ｎ_６は０または１であり、ｎ_５＋ｎ_６＝１〜４の整数であり、Ｒ_５およびＲ_６は、それぞれ独立に、親水基含有置換基または非親水基含有置換基であって、Ｒ_５およびＲ_６のうち少なくとも１つは親水基含有置換基である。ただし、前記親水基含有置換基が水酸基である場合を除く。］

[In formula (a1′-1), R ¹ is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and A and B are each independently a divalent carbon atom which may have a substituent. A hydrogen group, n ₁ is 0 or 1, and R ² is an acid dissociable, dissolution inhibiting group. ]
[In Formula (a3′-1), R ³ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ⁴ represents an alkylene group, n ₄ represents 0 or 1, and n ₅ represents 0 to 0. 4, n ₆ is 0 or 1, n ₅ + n ₆ = 1 to 4, and R ₅ and R ₆ are each independently a hydrophilic group-containing substituent or a non-hydrophilic group-containing substituent. And at least one of R ₅ and R ₆ is a hydrophilic group-containing substituent. However, the case where the hydrophilic group-containing substituent is a hydroxyl group is excluded. ]

  According to a third 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 second aspect, a step of exposing the resist film, and an alkali development of the resist film. And a resist pattern forming method including a step of forming a resist pattern.

In the present specification and claims, unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups. Further, the “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups unless otherwise specified.
The “lower alkyl group” is an alkyl group having 1 to 5 carbon atoms.
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.
“Structural unit” means a monomer unit (monomer unit) constituting a polymer compound (polymer, copolymer).
“Exposure” is a concept that includes general irradiation of radiation.

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

≪Polymer compound (A1) ≫
The polymer compound (A1) has a structural unit (a1 ′) represented by the general formula (a1′-1) and a structural unit (a3 ′) represented by the general formula (a3′-1). It is a copolymer.

<Structural unit (a1 ′)>
In formula (a1′-1), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group.
The lower alkyl group for R ¹ is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group. Group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like.
The halogenated lower alkyl group for R ¹ is a group in which part or all of the hydrogen atoms of the lower alkyl group are substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
R ¹ is preferably a hydrogen atom, a lower alkyl group or a fluorinated lower alkyl group, and most preferably a hydrogen atom or a methyl group from the viewpoint of industrial availability.

n ₁ is 0 or 1. When n ₁ is represented by 0, the polymer compound (A1) is represented by the following general formula (a1′-1-1), and when n ₁ is represented by 1, the following general formula (a1′- It is represented by 1-2).

［式中、Ｒ^１、Ａ、Ｂ、Ｒ^２はそれぞれ前記と同じである。］

[Wherein R ¹ , A, B and R ² are the same as defined above. ]

A is a divalent hydrocarbon group which may have a substituent. The hydrocarbon group having “substituent” means that part or all of the hydrogen atoms in the hydrocarbon group are substituted with groups or atoms other than hydrogen atoms.
The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.
Here, “aliphatic” in the claims and the specification is a relative concept with respect to aromatics, and is defined to mean a group, a compound, or the like that does not have aromaticity. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group for A may be saturated or unsaturated, and is usually preferably saturated.

  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.

In A, the linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and 1 to 5 carbon atoms. Is particularly preferred and 1 or 2 is most preferred.
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 -, - CH (CH 2 Alkylethylene groups such as CH ₃ ) CH ₂ —; alkyltrimethylene groups such as —CH (CH ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) CH ₂ —; —CH (CH ₃ ) CH _{2 CH 2 CH 2 -, - CH} 2 CH (CH 3) CH 2 CH 2 - , etc. And alkyl alkylene groups such as Le Kill tetramethylene group. 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 lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (═O), and the like.

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

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

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

R ² is an acid dissociable, dissolution inhibiting group. The acid dissociable, dissolution inhibiting group is an acid that is dissociated by the action of an acid generated from the acid generator component upon exposure when the polymer compound (A1) is blended with the acid generator component in a positive resist composition. In addition to having dissociation properties, before the dissociation, the polymer compound (A1) has an alkali dissolution inhibiting property that makes the entire polymer compound (A1) hardly soluble in an alkali developer.
As the acid dissociable, dissolution inhibiting group for R ² , those proposed so far as the acid dissociable, dissolution inhibiting group for base resins for chemically amplified resists can be used. In general, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like; an acetal-type acid dissociable, dissolution inhibiting group such as an alkoxyalkyl group is widely known. . The “(meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.

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

“Aliphatic branched” means having a branched structure having no aromaticity.
The structure of the “aliphatic branched acid dissociable, dissolution inhibiting group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The hydrocarbon group may be either saturated or unsaturated, but is usually preferably saturated.
Examples of aliphatic branched, acid dissociable, dissolution inhibiting group ^include groups represented by ^{-C (R 7) (R 8} ) (R 9). In formula, R < ⁷ > -R < ⁹ > is a C1-C5 linear alkyl group each independently. The group represented by —C (R ⁷ ) (R ⁸ ) (R ⁹ ) preferably has 4 to 8 carbon atoms, and specifically includes a tert-butyl group, a tert-pentyl group, and a tert-heptyl group. Groups and the like.

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The aliphatic cyclic group may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.
The basic ring structure of the aliphatic cyclic group excluding substituents 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 monocycloalkanes, bicycloalkanes, tricycloalkanes, tetracycloalkanes which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group. And groups obtained by removing one or more hydrogen atoms from a polycycloalkane. More specifically, a monocycloalkane such as cyclopentane or cyclohexane, or a group obtained by removing one or more hydrogen atoms from a polycycloalkane such as adamantane, norbornane, isobornane, dicyclodecane, tricyclodecane, or tetracyclododecane. Can be mentioned.

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 monovalent And a group having an aliphatic cyclic group and a branched alkylene having a tertiary carbon atom bonded thereto.
(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 an aliphatic cyclic group and a branched alkylene having a tertiary carbon atom bonded thereto include, for example, the following general formulas (2-1) to (2-6): ) And the like.

［式中、Ｒ^１４は低級アルキル基であり、ｇは０〜８の整数である。］

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

［式中、Ｒ^１５およびＲ^１６は、それぞれ独立にアルキル基である。］

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

As the alkyl group for R ^{14 to} R ¹⁶ , a lower alkyl group is preferable, and a linear or branched alkyl group is preferable. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group. 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.
g is preferably an integer of 0 to 3, more preferably an integer of 1 to 3, and still more preferably 1 or 2.

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

［式中、Ｒ^１’，Ｒ^２’はそれぞれ独立して水素原子または低級アルキル基を表し、ｎは０〜３の整数を表し、Ｙは低級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 a lower alkyl group, n represents an integer of 0 to 3, and Y represents a lower alkyl group or 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 lower alkyl group for R ¹ ′ and R ² ′ include the same lower alkyl groups as those described above for R. A methyl group or an ethyl group is preferable, and a methyl group is most preferable.
In the present invention, it is preferable that at least one of R ¹ ′ and R ² ′ is a hydrogen atom. That is, the acid dissociable, dissolution inhibiting group (p1) is preferably a group represented by the following general formula (p1-1).

［式中、Ｒ^１’、ｎ、Ｙは上記と同様である。］

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

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

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

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

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

In R ¹⁷ and R ¹⁸ , the alkyl group preferably has 1 to 15 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group. In particular, it is preferable that one of R ¹⁷ and R ¹⁸ is a hydrogen atom and the other is a methyl group.
R ¹⁹ is a linear, branched or cyclic alkyl group, preferably having 1 to 15 carbon atoms, and may be any of linear, branched or cyclic.
When R ¹⁹ is linear or branched, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ¹⁹ is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group, are included. Examples include a group excluding a hydrogen atom. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
In the above formula, R ¹⁷ and R ¹⁹ are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 5 carbon atoms), and the end of R ^{19 and} the end of R ¹⁷ And may be combined.
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 (3-1) to (3-12).

［式中、Ｒ^１３は水素原子またはメチル基であり、ｇは前記と同じである。］

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

In the present invention, R ² is preferably a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, and a tertiary carbon atom is formed on the ring skeleton of the above-mentioned (i) monovalent aliphatic cyclic group. The group represented by formula (1-1) or (1-2) is more preferable.

  As the structural unit (a1 ′), a structural unit represented by general formula (a1′-11) or (a1′-12) shown below is particularly desirable.

［式中、Ｒ^１、Ｒ^１４、ｎ_１はそれぞれ前記と同じであり、Ｒ^１０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_２は０〜３の整数である。］

Wherein R ¹ , R ¹⁴ and n ₁ are the same as defined above, R ¹⁰ is a hydrogen atom or a methyl group, a is an integer of 1 to 10, and n ₂ is an integer of 0 to 3. is there. ]

a is preferably an integer of 1 to 5, and most preferably 1 or 2.
n ₂ is preferably 1 or 2, and most preferably 2.

The structural unit (a1 ′) contained in the polymer compound (A1) may be one type or two or more types.
In the polymer compound (A1), the proportion of the structural unit (a1 ′) is the total proportion of the structural unit (a1 ′) and the structural unit (a1) described later (when the structural unit (a1) is not included). Is a proportion in which the proportion of the structural unit (a1 ′) is from 10 to 80 mol%, more preferably from 20 to 70 mol%, based on all structural units constituting the polymer compound (A1). Most preferred is an amount of 25-50 mol%. 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.
In particular, the resolution of the positive resist composition containing the polymer compound (A1) and the lithography properties such as the resist pattern shape are improved, so that the proportion of the structural unit (a1 ′) is such that the polymer compound (A1) ) Is preferably 10 mol% or more, and more preferably 20 mol% or more with respect to all the structural units constituting.

<Structural unit (a3 ′)>
In formula (a3′-1), R ³ is the same as R ¹ described above.
R ⁴ may be a linear alkylene group or a branched alkylene group, preferably a linear alkylene group.
The number of carbon atoms of R ⁴ is from 1 to 5 preferably 1 to 3 is more preferable. Specific examples of R ⁴ include the same alkylene groups as those described above for A and branched alkylene groups, and a methylene group and an ethylene group are preferable, and a methylene group is most preferable.
n ₄ may be 0 or 1.
When n ₄ is 0, the oxygen atom is bonded to the adamantane ring, and when n ₄ is 1, R ⁴ is bonded to the adamantane ring. The position of the adamantane ring to which the oxygen atom or R ⁴ is bonded is the 1- or 2-position, and the 1-position is preferred.

n ₅ is an integer from 0 to 4, more preferably an integer of 0 to 2. When n ₅ is an integer of 2 to 4, the plurality of R ⁵ may be the same or different.
n ₆ may be 0 or 1.
n ₅ + n ₆ (that is, the total number of substituents bonded to the adamantane ring) is an integer of 1 to 4, and more preferably 1 to 3.

R ₅ and R ₆ are each independently a hydrophilic group-containing substituent or a non-hydrophilic group-containing substituent, and at least one of R ₅ and R ₆ is a hydrophilic group-containing substituent.
The hydrophilic group-containing substituent is a group or atom containing a hydrophilic group in the structure thereof, and the hydrophilic group means a group or atom having an affinity for water. The hydrophilic group-containing substituent increases the hydrophilicity of the polymer compound (A1), and hence the affinity with the developer, improves the alkali solubility in the exposed area, and contributes to the improvement of the resolution. Moreover, the resist pattern shape formed is improved by having the structural unit (a3 ′) having such a hydrophilic group-containing substituent together with the structural unit (a1 ′).
The hydrophilic group-containing substituent may be composed of only a hydrophilic group, or may be a combination of a hydrophilic group and a group or atom other than the hydrophilic group.
Specific examples of the hydrophilic group include a hydroxy group (—OH), a carboxy group (—COOH), a carbonyl group (—C (═O) —), and an oxygen atom (—O—, ═O).
Examples of combinations of a hydrophilic group and a group or atom other than a hydrophilic group include, for example, a hydroxyalkyl group, a hydroxyfluoroalkyl group (a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom), Examples thereof include a hydroxyalkyloxy group, an alkyloxy group, an alkyloxyalkyl group (ether group), an alkyloxyalkyloxy group, an alkyloxycarbonyloxy group, an alkoxycarbonylalkyloxy group, and an alkyloxycarbonyl group.

The hydrophilic group-containing substituent is preferably at least one selected from the group consisting of —OH, ═O, hydroxyalkyl group, hydroxyalkyloxy group, alkyloxy group, alkyloxycarbonyloxy group, and in particular, ═O, alkyl At least one selected from the group consisting of an oxy group and an alkyloxycarbonyloxy group is preferred.
The alkyl group in the hydroxyalkyl group, hydroxyfluoroalkyl group, and alkyloxy group may be linear or branched, and preferably has 1 to 10 carbon atoms. 5 is more preferable, and 1-2 is particularly preferable.
The alkyl group in the alkyloxycarbonyloxy group is preferably a cyclic or chain-like tertiary alkyl group. Specifically, the tertiary alkyl ester-type acid dissociable, dissolution inhibiting groups listed in the structural unit (a1 ′) are used. The same thing is mentioned.
The hydrophilic group-containing substituent is particularly preferably a group containing a hydrophilic group other than a hydroxy group and not containing a hydroxy group because sensitivity and the like are improved. Particularly, = O, an alkyloxy group, an alkyloxycarbonyloxy group. At least one selected from the group consisting of

The non-hydrophilic group-containing substituent is a group or atom that does not contain a hydrophilic group in its structure, and specific examples include an alkyl group, a halogen atom, and a halogenated alkyl group.
The alkyl group is preferably a linear or branched alkyl group, preferably having 1 to 5 carbon atoms, and specifically, the same as the lower alkyl group for R ¹ can be mentioned.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with halogen atoms, with fluorinated alkyl groups being particularly preferred.

In the present invention, at least one of R ⁵ and R ⁶ is a hydrophilic group-containing substituent.
In the structural unit (a3 ′), the number of hydrophilic group-containing substituents bonded to the adamantane ring is preferably 1 to 3, and most preferably 1.
The bonding position of the hydrophilic group-containing substituent is preferably at least one of 2-position, 3-position, and 4-position of the adamantane ring, and more preferably 3-position or 4-position.
In the structural unit (a3 ′), the number of non-hydrophilic group-containing substituents bonded to the adamantane ring is preferably 0 to 3, and more preferably 0 to 2.
The bonding position of the non-hydrophilic group-containing substituent is preferably at least one of the 3-position, 4-position, 5-position, and 7-position of the adamantane ring, and more preferably 5-position and / or 7-position.

In the present invention, among the above, n ₄ = 0, n ₅ = 0, n ₆ = 1 and R ⁶ is a hydroxyl group is excluded. That is, in the general formula (a3′-1), n ₄ = 0, n ₅ = 0, n ₆ = 1, and R ⁶ is a structural unit (for example, a structure derived from 3-hydroxyadamantyl (meth) acrylate) (Unit) does not correspond to the structural unit (a3 ′).

  As the structural unit (a3 ′), structural units represented by general formulas (a3′-11) to (a3′-16) shown below are preferable.

In formulas (a3′-11) to (a3′-16), R ³ is the same as described above.
R ^{51 to} R ⁵⁵ are each independently a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples include the same as the lower alkyl group for R ¹ .
R ^{56 to} R ⁵⁷ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom.
R ^{61 to} R ⁶² are each independently a linear or branched alkylene group having 1 to 5 carbon atoms, and preferably 1 to 3 carbon atoms. Specific examples include the same linear alkylene groups and branched alkylene groups as mentioned in A above, preferably a methylene group, an ethylene group, etc., and most preferably an ethylene group.
R ⁷¹ is a linear or branched alkylene group having 1 to 5 carbon atoms, preferably a methylene group or an ethylene group, and most preferably a methylene group.

As the structural unit (a3 ′), one type may be used alone, or two or more types may be used in combination.
In the polymer compound (A1), the proportion of the structural unit (a3 ′) is preferably from 5 to 50 mol%, more preferably from 5 to 40 mol%, based on all structural units constituting the polymer compound (A1). 5-25 mol% is more preferable. Within the above range, the balance with other structural units is good, and various lithography properties such as resolution and resist pattern shape are improved.

The polymer compound (A1) may be a copolymer composed only of the structural units (a1 ′) and (a3 ′), or may be a copolymer containing other structural units.
When the polymer compound (A1) of the present invention is a copolymer containing other structural units other than the structural units (a1 ′) and (a3 ′), other than the structural units (a1 ′) and (a3 ′) The other structural unit is not particularly limited, and may be any structural unit that has been used for the base resin for chemically amplified resists. Specific examples include the following structural units (a1) to (a4).
Among these, the polymer compound (A1) preferably further has a structural unit (a2) in addition to the structural units (a1 ′) and (a3 ′).

<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, and when it is only the lactone ring, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure.
The lactone cyclic group of the structural unit (a2) has an affinity for a developer containing water or a high-molecular compound (A1) when the polymer film (A1) is used for forming a resist film. It is effective in improving the sex.

As the structural unit (a2), any unit can be used without any particular limitation.
Specifically, examples of the lactone-containing monocyclic group include groups in which one hydrogen atom has been removed from γ-butyrolactone. 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、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’は水素原子、低級アルキル基、炭素数１〜５のアルコキシ基または−ＣＯＯＲ”であり、前記Ｒ”は水素原子、または炭素数１〜１５の直鎖状、分岐鎖状もしくは環状のアルキルキル基であり、ｍは０または１の整数であり、Ａ”は炭素数１〜５のアルキレン基または酸素原子である。］

[Wherein, R is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ′ is a hydrogen atom, a lower alkyl group, an alkoxy group having 1 to 5 carbon atoms, or —COOR ″, wherein R ″ is A hydrogen atom or a linear, branched or cyclic alkylalkyl group having 1 to 15 carbon atoms, m is an integer of 0 or 1, and A ″ is an alkylene group having 1 to 5 carbon atoms or an oxygen atom. is there.]

R in the general formulas (a2-1) to (a2-5) is the same as R ¹ in the structural unit (a1 ′).
As the lower alkyl group for R ′, the same as the lower alkyl group for R ¹ in the structural unit (a1 ′) can be exemplified.
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 fluorine atom A group in which one or more hydrogen atoms are removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, etc., which may or may not be substituted with an alkyl group. Specific examples thereof include monocycloalkanes such as cyclopentane and cyclohexane, groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Can be mentioned.
Specific examples of the alkylene group having 1 to 5 carbon atoms of A ″ include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group.
In general formulas (a2-1) to (a2-5), R ′ is preferably a hydrogen atom in view of industrial availability.
Below, the specific structural unit of the said general formula (a2-1)-(a2-5) is illustrated.

  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 ( At least one selected from the group consisting of structural units represented by a2-3) is more preferred. Among them, chemical formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-2), (a2-3-1), (a2-3-2) ), (A2-3-9) and (a2-3-10), at least one selected from the group consisting of structural units represented by (a2-3-10) is preferred.

As the structural unit (a2), one type may be used alone, or two or more types may be used in combination.
In the polymer compound (A1), the proportion of the structural unit (a2) is preferably from 5 to 60 mol%, more preferably from 10 to 50 mol%, based on the total of all the structural units constituting the polymer compound (A1). Preferably, 20-50 mol% is more preferable. By making it the lower limit value or more, the effect of containing the structural unit (a2) can be sufficiently obtained, and by making it the upper limit value or less, it is possible to balance with other structural units.
You can take

<Structural unit (a1)>
The polymer compound (A1) is a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group, which does not fall under the structural unit (a1 ′) as long as the effects of the present invention are not impaired. You may have.
As the acid dissociable, dissolution inhibiting group in the structural unit (a1), the same groups as those mentioned above for the acid dissociable, dissolution inhibiting group for R ² can be mentioned.

  As the structural unit (a1), structural units represented by general formula (a1-0-1) shown below are preferred.

［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を示し；Ｘ^１は酸解離性溶解抑制基を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; and X ¹ represents an acid dissociable, dissolution inhibiting group. ]

In general formula (a1-0-1), the lower alkyl group or halogenated lower alkyl group for R is the same as the lower alkyl group or halogenated lower alkyl group that may be bonded to the α-position of the acrylate ester. .
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.

  More specifically, examples of the structural unit (a1) include structural units represented by the following general formulas (a1-1) to (a1-2).

［上記式中、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の低級アルキル基、または脂肪族環式基を表し；ｎは０〜３の整数を表し；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の低級アルキル基を表す。］

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

Wherein, X 'include those of 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.

  Specific examples of the structural units represented by the general formulas (a1-1) to (a1-2) are shown below.

Among the above, the structural unit represented by the general formula (a1-1) is preferable, and specifically, (a1-1-1) to (a1-1-6) and (a1-1-35) to (a1). It is more preferable to use at least one selected from the group -1-41).
Furthermore, as the structural unit (a1), in particular, those represented by the following general formula (a1-1-01) including the structural units of the formulas (a1-1-1) to (a1-1-4) The following general formula (a1-1-02) including the structural units of formulas (a1-1-35) to (a1-1-41) is also preferable.

（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を示し、Ｒ^１１は低級アルキル基を示す。）

(In the formula, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and R ¹¹ represents a lower alkyl group.)

（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を示し、Ｒ^１２は低級アルキル基を示す。ｈは１〜３の整数を表す）

(In the formula, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ¹² represents a lower alkyl group, and h represents an integer of 1 to 3)

In general formula (a1-1-01), R is the same as defined above.
The lower alkyl group for R ^{11 is the same as} the lower alkyl group for R, and is preferably a methyl group or an ethyl group.
In general formula (a1-1-02), R is the same as defined above.
The lower alkyl group for R ^{12 is the same as} the lower alkyl group for R, preferably a methyl group or an ethyl group, and most preferably an ethyl group.
h is preferably 1 or 2, and most preferably 2.

In the polymer compound (A1), as the structural unit (a1), one type of structural unit may be used alone, or two or more types may be used in combination.
In the polymer compound (A1), the proportion of the structural unit (a1) is such that the total proportion of the structural unit (a1 ′) and the structural unit (a1) constitutes the polymer compound (A1). An amount of 10 to 80 mol% is preferable, an amount of 20 to 70 mol% is more preferable, and an amount of 25 to 50 mol% is most preferable with respect to all the structural units. 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 (a3)>
The polymer compound (A1) is a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group that does not fall under the structural unit (a3 ′) as long as the effects of the present invention are not impaired. ).
The polar group in the structural unit (a3), like the hydrophilic group-containing substituent of the structural unit (a3 ′), increases the hydrophilicity of the polymer compound (A1) and thus the affinity with the developer, Improves alkali solubility and contributes to improved resolution.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom.
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、ｋは１〜３の整数であり、ｔ’は１〜３の整数であり、ｌは１〜５の整数であり、ｓは１〜３の整数である。）

Wherein R is the same as above, k is an integer of 1 to 3, t ′ is an integer of 1 to 3, l is an integer of 1 to 5, and s is an integer of 1 to 3. .)

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.

<Structural unit (a4)>
The polymer compound (A1) is a structural unit (a4) other than the structural units (a1 ′), (a3 ′), (a2), (a1), and (a3) as long as the effects of the present invention are not impaired. ) May be included.
The structural unit (a4) is not particularly limited as long as it is another structural unit not classified into the structural units (a1 ′), (a3 ′), (a2), (a1), and (a3). ArF Many conventionally known ones can be used as resist resins for excimer lasers, KrF excimer lasers (preferably for ArF excimer lasers), and the like.
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing a non-acid-dissociable aliphatic polycyclic group is preferable. 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。）

(In the formula, R is as defined above.)

  When such a structural unit (a4) is contained in the polymer compound (A1), the proportion of the structural unit (a4) in the polymer compound (A1) is the sum of all the structural units constituting the polymer compound (A1). On the other hand, 1-30 mol% is preferable and 10-20 mol% is more preferable.

In the present invention, the polymer compound (A1) is preferably a copolymer having the structural units (a1 ′), (a3 ′) and (a2). Examples of the copolymer include copolymers composed of the structural units (a1 ′), (a3 ′) and (a2), structural units (a1 ′), (a3 ′) and (a2).
As the polymer compound (A1), in particular, a constitutional unit represented by the formula (a1′-11) and a constitution represented by any one of the formulas (a3′-11) to (a3′-15). A copolymer having a unit and a structural unit represented by the formula (a2-2) is preferred.

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

The polymer compound (A1) can be obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN). it can.
Further, in the polymer compound (A1), a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination in the above polymerization. it may be introduced -C _{(CF 3)} 2 -OH group at the terminal. As described above, a copolymer introduced with a hydroxyalkyl group in which a part of hydrogen atoms of the alkyl group is substituted with a fluorine atom reduces development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing
As the monomer for deriving each structural unit, commercially available monomers may be used or synthesized.
For example, the monomer for deriving the structural unit (a1 ′) is a compound represented by the following general formula (I), and among these, a monomer in which n ₁ is 0 is commercially available. Further, the monomer _{n 1} is 1 (hereinafter. Referred to compound (I ')) can be produced by the method (1) or (2) shown in example below.

［式中、Ｒ^１、Ａ、Ｂ、ｎ_１およびＲ^２はそれぞれ前記と同じである。］

[Wherein R ¹ , A, B, n ₁ and R ² are the same as defined above. ]

[Production Method (1) of Compound (I ′)]
The production method (1) includes a compound represented by the following general formula (I-1) (hereinafter referred to as compound (I-1)) and a compound represented by the following general formula (I-2) (hereinafter referred to as “compound”). Compound (I-2)) is reacted to obtain a compound represented by the following general formula (I-3) (hereinafter referred to as Compound (I-3)) (hereinafter referred to as the first step). ), And a compound (I-3) is reacted with a compound represented by the following general formula (I-4) (hereinafter referred to as compound (I-4)) to obtain compound (I ′) ( Hereinafter, it is referred to as a second step).

^{R 1, A, B, R} 2 in the formula (I-1) ~ (I -4) , respectively, ^R 1, A in the general formula (I), B, is the same as ^{R 2.}
X ¹⁰ and X ¹² are each independently a hydroxyl group or a halogen atom, and one of X ¹⁰ and X ¹² is a hydroxyl group, the other is a halogen atom, and X ¹¹ is a halogen atom. Examples of the halogen atom include a bromine atom, a chlorine atom, an iodine atom, and a fluorine atom.
The halogen atom for X ¹⁰ or X ¹² is preferably a chlorine atom or a bromine atom because of excellent reactivity.
X ¹¹ is independently a halogen atom. Examples of the halogen atom include a bromine atom, a chlorine atom, an iodine atom, and a fluorine atom.
X ¹¹ is preferably a bromine atom or a chlorine atom and particularly preferably a bromine atom because of excellent reactivity.

"First step"
Compound (I-1) and compound (I-2) can be reacted by a known method. For example, the method of making compound (I-1) and compound (I-2) contact in reaction solvent in presence of a base is mentioned. This method can be carried out, for example, by adding compound (I-2) to a solution in which compound (I-1) is dissolved in a reaction solvent in the presence of a base.
As compound (I-1) and compound (I-2), commercially available compounds may be used or synthesized.
Compound (I-1) is a dihydric alcohol when X ¹⁰ is a hydroxyl group, and is a halogenated alcohol when X ¹⁰ is a halogen atom. Compound (I-1) is not particularly limited as long as it is a dihydric alcohol or a halogenated alcohol. Specific examples of the dihydric alcohol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol and the like. Specific examples of the halogenated alcohol include 2-bromo-1-ethanol, 3-chloro-1-propanol, 4-chloro-1-butanol, and 5-chloro-1-pentanol.
Examples of the compound (I-2) include 2-methyl-2-adamantyloxycarbonylmethyl chloride, 2-ethyl-2-adamantyloxycarbonylmethyl chloride, 1-methyl-1-cyclohexyloxycarbonylmethyl chloride, 1-ethyl-1 -Cyclohexyloxycarbonylmethyl chloride, 1-methyl-1-cyclopentyloxycarbonylmethyl chloride, 1-ethyl-1-cyclopentyloxycarbonylmethyl chloride and the like.
Any reaction solvent may be used as long as it can dissolve the starting compounds (I-1) and (I-2). Specifically, tetrahydrofuran (THF), acetone, dimethylformamide (DMF), dimethylacetamide , Dimethyl sulfoxide (DMSO), acetonitrile and the like.
Examples of the base include inorganic bases such as sodium hydride and K ₂ CO ₃ ; organic bases such as triethylamine, 4-dimethylaminopyridine (DMAP) and pyridine. In the first step, sodium hydride is particularly preferably used.
The amount of compound (I-2) added is preferably about 1 to 100 moles, more preferably 1 to 50 moles, with respect to compound (I-1).
The reaction temperature is preferably 0 to 50 ° C, more preferably 5 to 40 ° C, and most preferably a reaction at room temperature.
The reaction time varies depending on the reactivity and reaction temperature of the compound (I-1) and the compound (I-2), but usually 1 to 24 hours are preferable, and 3 to 12 hours are more preferable.

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

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

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

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

[Production Method (2) of Compound (I ′)]
In the second production method, a compound represented by the following general formula (I-5) (hereinafter referred to as compound (I-5)) is reacted with compound (I-2) to give compound (I ′ ) Is obtained (hereinafter referred to as the first 'step).

^{R 1, A, B, R} 2 in the formula (I-5) can be respectively, ^R 1, A in the general formula (I), B, is the same as ^{R 2.}

"First step"
Compound (I-5) and compound (I-2) can be reacted by a known method. For example, the method of making compound (I-5) and compound (I-2) contact in reaction solvent in presence of a base is mentioned. This method can be carried out, for example, by adding compound (I-2) to a solution in which compound (I-5) is dissolved in a reaction solvent in the presence of a base.
As compound (I-5) and compound (I-2), commercially available compounds may be used or synthesized. For example, specific examples of the compound (I-5) include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like.
Any reaction solvent may be used as long as it can dissolve the starting compound (I-5) and compound (I-2). Specific examples include tetrahydrofuran (THF), acetone, dimethylformamide (DMF), dimethylacetamide. , Dimethyl sulfoxide (DMSO), acetonitrile and the like.
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. In the first step, sodium hydride is particularly preferably used.
The amount of compound (I-2) added is preferably about 1 to 2 moles, more preferably 1 to 1.5 moles, relative to compound (I-5).
The reaction temperature is preferably 0 to 50 ° C, more preferably 5 to 40 ° C, and most preferably a reaction at room temperature.
The reaction time varies depending on the reactivity of the compound (I-5) and compound (I-2), the reaction temperature, and the like, but usually 1 to 24 hours is preferable and 3 to 12 hours is more preferable.

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

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

The polymer compound (A1) of the present invention is a novel compound not conventionally known.
For example, when the polymer compound (A1) is blended in a positive resist composition together with an acid generator component (B) that generates an acid upon irradiation with radiation, the acid generator component (B) upon exposure (irradiation with radiation). When an acid is generated from the acid, the bond between R ² in the structural unit (a1 ′) and the oxygen atom bonded thereto is broken by the action of the acid, and R ² is dissociated. As a result, the solubility of the polymer compound (A1) in the alkaline developer increases.
Therefore, the polymer compound (A1) is useful as a base resin for a chemically amplified positive resist composition, and can be suitably used as a base component (A) for the following positive resist composition of the present invention. .

≪Positive resist composition≫
The positive resist composition of the present invention comprises a base component (A) whose solubility in an alkaline developer is increased by the action of an acid (hereinafter referred to as component (A)), and an acid that generates an acid upon irradiation with radiation. Contains a generator component (B) (hereinafter referred to as component (B)). Here, the “base material component” is an organic compound having a film forming ability.
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.

<(A) component>
(A) A component contains the high molecular compound (A1) of this invention mentioned above.
In the component (A), the polymer compound (A1) may be used alone or in combination of two or more.
The proportion of the polymer compound (A1) in the component (A) is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, and 100% by mass with respect to the total mass of the component (A). Good.

Component (A) is a “base component whose solubility in an alkaline developer is increased by the action of an acid” (hereinafter referred to as component (A2)) other than the polymer compound (A1) as long as the effects of the present invention are not impaired. May be contained).
The component (A2) is not particularly limited, and many conventionally known base components for chemically amplified positive resist compositions (for example, for ArF excimer laser, for KrF excimer laser (preferably A base resin such as ArF excimer laser) may be arbitrarily selected and used. For example, the base resin for ArF excimer laser includes those having the structural unit (a1) as an essential structural unit and optionally further including the structural units (a2) to (a4).
(A2) A component may be used individually by 1 type and may be used in combination of 2 or more type.

  In the resist composition of the present invention, the content of the component (A) may be adjusted according to the resist film thickness to be formed.

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

  As the onium salt acid generator, for example, a compound represented by the following general formula (b-1) or (b-2) can be used.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”は、それぞれ独立に、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; And 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 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, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Is most preferred.
As the alkoxy group that may be substituted for the hydrogen atom of the aryl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, A tert-butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
The halogen atom that may be substituted with the hydrogen atom of the aryl group is preferably a fluorine atom.

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

R ⁴ ″ represents an alkyl group, a halogenated alkyl group, an aryl group, or an alkenyl group which may have a substituent.
The alkyl group for R ⁴ ″ may be linear, branched or cyclic.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.

Examples of the halogenated alkyl group for R ⁴ ″ include groups in which part or all of the hydrogen atoms of the linear, branched, or cyclic alkyl group have been substituted with halogen atoms. A fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
In the halogenated alkyl group, the ratio of the number of halogen atoms to the total number of halogen atoms and hydrogen atoms contained in the halogenated alkyl group (halogenation rate (%)) is preferably 10 to 100%. 50 to 100% is preferable, and 100% is most preferable. The higher the halogenation rate, the better the acid strength.

The aryl group for R ⁴ ″ is preferably an aryl group having 6 to 20 carbon atoms.
The alkenyl group in R ⁴ ″ is preferably an alkenyl group having 2 to 10 carbon atoms.

In the above R ⁴ ″, “optionally substituted” means one of hydrogen atoms in the linear, branched or cyclic alkyl group, halogenated alkyl group, aryl group, or alkenyl group. It means that part or all may be substituted with a substituent (an atom or group other than a hydrogen atom).
The number of substituents in R ⁴ ″ may be one or two or more.

Examples of the substituent include a halogen atom, a hetero atom, an alkyl group, R ⁵ —O— [wherein R ⁵ is a monovalent aromatic organic group, a monovalent aliphatic hydrocarbon group, or a hydroxyalkyl group. is there. ] Etc. which are represented by these.
Examples of the halogen atom and alkyl group include the same groups as those described above for R ⁴ ″ as the halogen atom and alkyl group in the halogenated alkyl group.
Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom.

In the group represented by R ⁵ —O—, the monovalent aromatic organic group represented by R ⁵ includes a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, An aryl group such as a phenanthryl group obtained by removing one hydrogen atom from an aromatic hydrocarbon ring; a part of carbon atoms constituting the ring of the aryl group is a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom Substituted heteroaryl groups; arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group and the like.
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.
These aryl group, heteroaryl group, and arylalkyl group may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, an alkoxy group, a hydroxyl group, or a halogen atom. 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. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom, and a fluorine atom is preferable.
The monovalent aromatic organic group for R ⁵ is preferably an arylalkyl group, more preferably an arylmethyl group, and most preferably a naphthylmethyl group.

Examples of the monovalent aliphatic hydrocarbon group for R ⁵ include a linear, branched or cyclic monovalent saturated hydrocarbon group having 1 to 15 carbon atoms, or a linear chain having 2 to 5 carbon atoms. Or branched monovalent aliphatic unsaturated hydrocarbon group.
Examples of the linear monovalent saturated hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decanyl group.
Examples of the branched monovalent saturated hydrocarbon group include 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1 -Ethylbutyl group, 2-ethylbutyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like can be mentioned.
The cyclic monovalent saturated hydrocarbon group may be either a polycyclic group or a monocyclic group, for example, one from a polycycloalkane such as a monocycloalkane, a bicycloalkane, a tricycloalkane, or a tetracycloalkane. And a group in which a hydrogen atom is removed. More specifically, one hydrogen atom was removed from a monocycloalkane such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane, and a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Group and the like.
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.
R The number of carbon atoms of the monovalent aliphatic hydrocarbon group having ^5, 2 to 4 and most preferably 3.

The hydroxyalkyl group for R ⁵ is a group in which at least one hydrogen atom of a linear, branched, or cyclic monovalent saturated hydrocarbon group is substituted with a hydroxyl group. Those in which one or two hydrogen atoms of a linear or branched monovalent saturated hydrocarbon group are substituted with a hydroxyl group are preferred. Specific examples include a hydroxymethyl group, a hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, and a 2,3-dihydroxypropyl group.
R The number of carbon atoms of the monovalent hydroxyalkyl group ^5, preferably 1 to 10, more preferably 1 to 8, particularly preferably 1 to 6, 1 to 3 is most preferred.

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

Specific examples of the onium salt acid generators represented by formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium. Trifluoromethane sulfonate or nonafluorobutane sulfonate, triphenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, tri (4-methylphenyl) sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its Nonafluorobutanesulfonate, dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, its heptaful 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) phenyl sulphonium trifluoromethane sulphonate, its heptafluoropropane sulphonate or its nonafluorobutane sulphonate; 1-phenyltetrahydrothiophenium trifluoromethane sulphonate, its heptafluoropropane sulphonate 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, onium salts in which the anion portion of these onium salts is replaced with methanesulfonate, n-propanesulfonate, n-butanesulfonate, or n-octanesulfonate can also be used.

  In addition, in the general formula (b-1) or (b-2), an onium salt-based acid generator in which the anion moiety is replaced with an anion moiety represented by the following general formula (b-3) or (b-4). Can also be used (the cation moiety is the same as (b-1) or (b-2)).

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

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

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

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

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

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

In R ^{41 to} R ⁴⁶ , the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a linear or branched alkyl group, and a methyl group, an ethyl group, a propyl group, an isopropyl group, n A butyl group or a tert-butyl group is particularly preferable.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a linear or branched alkoxy group, and particularly preferably a methoxy group or an ethoxy group.
The hydroxyalkyl group is preferably a group in which one or more hydrogen atoms in the alkyl group are substituted with a hydroxy group, and examples thereof include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.
When the symbols n _{1 to} n ₆ attached to R ^{41 to} R ⁴⁶ are integers of 2 or more, the plurality of R ^{41 to} R ⁴⁶ may be the same or different.
n ₁ is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.
n ₂ and n ₃ are preferably each independently 0 or 1, more preferably 0.
n ₄ is preferably 0 to 2, more preferably 0 or 1.
n ₅ is preferably 0 or 1, more preferably 0.
n ₆ is preferably 0 or 1, more preferably 1.

The anion part of the sulfonium salt having a cation part represented by the formula (b-5) or (b-6) is not particularly limited, and is the same as the anion part of the onium salt acid generators proposed so far. It may be a thing. Examples of the anion moiety include fluorinated alkyl sulfonate ions such as the anion moiety (R ^{4 ″} SO ₃ ⁻ ) of the onium salt acid generator represented by the general formula (b-1) or (b-2). The anion part represented by the general formula (b-3) or (b-4) and the like.

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

（式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。）

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

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

As the organic group for R ^32, a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^32, the same alkyl groups and aryl groups as those described above for R ³¹ can be used.
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

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

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

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

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

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

In the general formula (B-2), the alkyl group or halogenated alkyl group having no substituent of R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and carbon atoms. Numbers 1 to 6 are most preferable.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred.

As the aryl group of R ³⁴ , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, or a phenanthryl group. And a heteroaryl group in which a part of carbon atoms constituting the ring of these groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. Among these, a fluorenyl group is preferable.
The aryl group of R ³⁴ may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.

The alkyl group or halogenated alkyl group having no substituent for R ³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³⁵ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³⁵ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred is the strength of the acid generated. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

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

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

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

(B) As a component, these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.
In the present invention, as the component (B), it is preferable to use an onium salt acid generator having an anion of a fluorinated alkyl sulfonate ion which may have a substituent.
0.5-30 mass parts is preferable with respect to 100 mass parts of (A) component, and, as for content of (B) component in the positive resist composition of this invention, 1-10 mass parts is more preferable. By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

<Optional component>
In the positive resist composition of the present invention, a nitrogen-containing organic compound (D) (hereinafter, referred to as “component (D)”) is further added as an optional component in order to improve the resist pattern shape, stability with time, and the like. Can be blended.
Since a wide variety of components (D) have already been proposed, any known one may be used. Among them, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are used. preferable. Here, the aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of the aliphatic amine include an amine (alkyl amine 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 12 or less carbon atoms.
Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di- -Dialkylamines such as n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine , Tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine, etc .; diethanolamine, triethanolamine, diisopropanolamine Triisopropanolamine, di -n- octanol amines, alkyl alcohol amines tri -n- octanol amine. Among these, a C5-C10 trialkylamine is preferable and a tri-n-pentylamine is the most 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.
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.

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

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

<Organic solvent (S)>
The positive resist composition of the present invention can be produced by dissolving the material in an organic solvent (hereinafter sometimes referred to as (S) component).
As the component (S), any component can be used as long as it can dissolve each component to be used to form a uniform solution. Conventionally, any one of known solvents for chemically amplified resists can be used. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone;
Ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, 2-heptanone;
Polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol;
Compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, 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 the 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 2 -20% by mass, preferably 5-15% by mass.

The positive resist composition of the present invention is a novel one that has not been known so far.
In addition, according to the positive resist composition of the present invention, a resist pattern having high resolution and excellent shape (for example, roundness of a hole pattern) can be formed on a support.
In particular, when the structural unit (a3 ′) in the polymer compound (A1) contains a hydrophilic group other than a hydroxyl group as a hydrophilic group, the sensitivity is further improved.

≪Resist pattern formation method≫
The resist pattern forming method of the present invention includes 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 pattern. Forming a step.
The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, first, the positive resist composition is applied onto a support with a spinner or the like, and pre-baked (post-apply bake (PAB)) for 40 to 120 seconds, preferably 60 to 90, under a temperature condition of 80 to 150 ° C. For example, ArF excimer laser light is selectively exposed through a desired mask pattern using an ArF exposure apparatus or the like, and then subjected to PEB (post-exposure heating) at a temperature of 80 to 150 ° C. for 40 to 120. Second, preferably 60-90 seconds. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide (TMAH), preferably rinsed with pure water and dried. In some cases, a baking process (post-bake) may be performed after the development process. In this way, a resist pattern faithful to the mask pattern can be obtained.

The support is not particularly limited, and a conventionally known one can be used, and examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
Further, the support may be a substrate in which an inorganic and / or organic film is provided on the above-described substrate. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include an organic antireflection film (organic BARC).

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

The exposure 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.
In immersion exposure, as described above, the portion between the lens, which has been conventionally filled with an inert gas such as air or nitrogen, and the resist film on the wafer is refracted larger than the refractive index of air. The exposure is performed in a state filled with a solvent having a high rate (immersion medium).
More specifically, the immersion exposure is a solvent (immersion medium) having a refractive index larger than the refractive index of air between the resist film obtained as described above and the lowermost lens of the exposure apparatus. And in that state, exposure can be performed through a desired mask pattern (immersion exposure).
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 exposed by the immersion exposure 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.).

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.
In the following Synthesis Example 1 (Reference Example), Synthesis Examples 2 to 5 (Examples), and Comparative Synthesis Example 1, compounds represented by the following formulas [1] to [9] (hereinafter referred to as [Compound 1], respectively) as monomers. To [Compound 9]).

[Synthesis Example 1]
4.99 g (23.97 mmol) of [Compound 1], 7.00 g (23.97 mmol) of [Compound 2], 1.41 g (5.33 mmol) of [Compound 3] were dissolved in 53.60 g of methyl ethyl ketone. I let you. To this solution, 6.39 mmol of Wako Pure Chemical V-601 (polymerization initiator) was added and dissolved. The resultant was dropwise added to 22.33 g of methyl ethyl ketone heated to 75 ° C. in a nitrogen atmosphere over 6 hours. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature.
Thereafter, the operation of dropping the reaction solution into a large amount of methanol / water solution and precipitating the copolymer was repeated twice. The copolymer thus obtained was dried under reduced pressure at room temperature to obtain a white powder. This is referred to as polymer compound (1), and the structural formula thereof is shown below.
As a result of measuring the carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) at 600 MHz for the polymer compound (1), the polymer composition (ratio (molar ratio) of each structural unit in the structural formula) was 1 / m / n = 44.6 / 44.9 / 10.5. Moreover, the standard polystyrene conversion mass mean molecular weight calculated | required by GPC measurement was 8,200, and dispersion degree was 1.95.

[Synthesis Example 2]
4.99 g (23.97 mmol) of [Compound 1], 7.00 g (23.97 mmol) of [Compound 2], 1.79 g (5.33 mmol) of [Compound 4] were dissolved in 55.12 g of methyl ethyl ketone. I let you. To this solution, 5.86 mmol of V-601 (polymerization initiator) manufactured by Wako Pure Chemical Industries, Ltd. was added and dissolved. The resultant was dropwise added to 22.97 g of methyl ethyl ketone heated to 75 ° C. in a nitrogen atmosphere over 6 hours. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature.
Thereafter, the operation of dropping the reaction solution into a large amount of methanol / water solution and precipitating the copolymer was repeated twice. The copolymer thus obtained was dried under reduced pressure at room temperature to obtain a white powder. This is referred to as polymer compound (2), and the structural formula thereof is shown below.
As a result of measuring 600 MHz — ¹³ C-NMR for the polymer compound (2), the polymer composition (ratio (molar ratio) of each structural unit in the structural formula) was 1 / m / n = 44.5 / 45.1. /10.4. Moreover, the standard polystyrene conversion mass mean molecular weight calculated | required by GPC measurement was 8,800, and dispersion degree was 2.20.

[Synthesis Example 3]
4.99 g (23.97 mmol) of [Compound 1], 7.00 g (23.97 mmol) of [Compound 2] and 1.49 g (5.33 mmol) of [Compound 5] were dissolved in 53.92 g of methyl ethyl ketone. I let you. To this solution, 6.39 mmol of Wako Pure Chemical V-601 (polymerization initiator) was added and dissolved. The resultant was dropwise added to 22.47 g of methyl ethyl ketone heated to 75 ° C. in a nitrogen atmosphere over 6 hours. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature.
Thereafter, the operation of dropping the reaction solution into a large amount of methanol / water solution and precipitating the copolymer was repeated twice. The copolymer thus obtained was dried under reduced pressure at room temperature to obtain a white powder. This is referred to as polymer compound (3), and the structural formula thereof is shown below.
As a result of measuring 600 MHz — ¹³ C-NMR for the polymer compound (3), the polymer composition (ratio (molar ratio) of each structural unit in the structural formula) was 1 / m / n = 45.4 / 44.8. /9.8. Further, the mass average molecular weight in terms of standard polystyrene determined by GPC measurement was 7,700, and the degree of dispersion was 2.07.

[Synthesis Example 4]
4.99 g (23.97 mmol) of [Compound 1], 7.00 g (23.97 mmol) of [Compound 2] and 1.25 g (5.33 mmol) of [Compound 6] are dissolved in 52.96 g of methyl ethyl ketone. I let you. To this solution, 6.66 mmol of Wako Pure Chemical V-601 (polymerization initiator) was added and dissolved. The resultant was dropwise added to 22.01 g of methyl ethyl ketone heated to 75 ° C. in a nitrogen atmosphere over 6 hours. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature.
Thereafter, the operation of dropping the reaction solution into a large amount of methanol / water solution and precipitating the copolymer was repeated twice. The copolymer thus obtained was dried under reduced pressure at room temperature to obtain a white powder. This is referred to as polymer compound (4), and the structural formula thereof is shown below.
As a result of measuring 600 MHz — ¹³ C-NMR for the polymer compound (4), the polymer composition (ratio (molar ratio) of each structural unit in the structural formula) was 1 / m / n = 45.3 / 44.9. /9.8. In addition, the standard polystyrene equivalent weight average molecular weight determined by GPC measurement was 7,900, and the degree of dispersion was 2.14.

[Synthesis Example 5]
4.99 g (23.97 mmol) of [Compound 1], 7.00 g (23.97 mmol) of [Compound 2], 1.41 g (5.33 mmol) of [Compound 7] were dissolved in 53.60 g of methyl ethyl ketone. I let you. To this solution, 6.39 mmol of Wako Pure Chemical V-601 (polymerization initiator) was added and dissolved. The resultant was dropwise added to 22.33 g of methyl ethyl ketone heated to 75 ° C. in a nitrogen atmosphere over 6 hours. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature.
Thereafter, the operation of dropping the reaction solution into a large amount of methanol / water solution and precipitating the copolymer was repeated twice. The copolymer thus obtained was dried under reduced pressure at room temperature to obtain a white powder. This is referred to as polymer compound (5), and the structural formula thereof is shown below.
As a result of measuring 600 MHz — ¹³ C-NMR for the polymer compound (5), the polymer composition (ratio (molar ratio) of each structural unit in the structural formula) was 1 / m / n = 45.7 / 44.9. /9.4. Moreover, the standard polystyrene conversion mass mean molecular weight calculated | required by GPC measurement was 8,300, and dispersion degree was 2.14. From these results, it was found that the obtained compound was a polymer compound (5).

[Synthesis Example 6]
12.46 g (59.93 mmol) of [Compound 1], 7.00 g (23.97 mmol) of [Compound 2], 8.92 g (35.96 mmol) of [Compound 9], 7.01 g (29.96 mmol) Of [Compound 6] was dissolved in 141.56 g of methyl ethyl ketone. To this solution, 20.98 mmol of Wako Pure Chemicals V-601 (polymerization initiator) was added and dissolved. The resultant was dropwise added to 58.98 g of methyl ethyl ketone heated to 75 ° C. in a nitrogen atmosphere over 6 hours. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature.
Thereafter, the operation of dropping the reaction solution into a large amount of methanol / water solution and precipitating the copolymer was repeated twice. The copolymer thus obtained was dried under reduced pressure at room temperature to obtain a white powder. This is referred to as polymer compound (6) and the structural formula is shown below.
As a result of measuring 600 MHz — ¹³ C-NMR for the polymer compound (6), the polymer composition (ratio (molar ratio) of each structural unit in the structural formula) was 1 / m / n / o = 40.3 / 15. 1 / 24.8 / 19.8. Moreover, the standard polystyrene conversion mass mean molecular weight calculated | required by GPC measurement was 7,300, and dispersion degree was 1.95.

[Synthesis Example 7]
12.46 g (59.93 mmol) of [Compound 1], 10.50 g (35.96 mmol) of [Compound 2], 5.94 g (23.97 mmol) of [Compound 9], 7.01 g (29.96 mmol) [Compound 6] was dissolved in 143.64 g of methyl ethyl ketone. To this solution, 22.47 mmol of W-Pure V-601 (polymerization initiator) was added and dissolved. The resultant was dropwise added to 59.85 g of methyl ethyl ketone heated to 75 ° C. in a nitrogen atmosphere over 6 hours. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature.
Thereafter, the operation of dropping the reaction solution into a large amount of methanol / water solution and precipitating the copolymer was repeated twice. The copolymer thus obtained was dried under reduced pressure at room temperature to obtain a white powder. This was designated as polymer compound (7) (the structural formula is the same as for polymer compound (6) above).
As a result of measuring 600 MHz — ¹³ C-NMR for the polymer compound (7), the polymer composition (ratio (molar ratio) of each structural unit in the structural formula) was 1 / m / n / o = 40.0 / 24. It was 0.8 / 8.1 / 20.1. Moreover, the standard polystyrene conversion mass mean molecular weight calculated | required by GPC measurement was 7,500, and dispersion degree was 1.98.

[Comparative Synthesis Example 1]
Dissolve 4.99 g (23.97 mmol) of [Compound 1], 7.00 g (23.97 mmol) of [Compound 2], 1.26 g (5.33 mmol) of [Compound 8] in 53.00 g of methyl ethyl ketone. I let you. To this solution, 5.86 mmol of V-601 (polymerization initiator) manufactured by Wako Pure Chemical Industries, Ltd. was added and dissolved. The resultant was dropwise added to 22.08 g of methyl ethyl ketone heated to 75 ° C. in a nitrogen atmosphere over 6 hours. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature.
Thereafter, the operation of dropping the reaction solution into a large amount of methanol / water solution and precipitating the copolymer was repeated twice. The copolymer thus obtained was dried under reduced pressure at room temperature to obtain a white powder. This is designated as polymeric compound (8), and the structural formula thereof is shown below.
As a result of measuring 600 MHz — ¹³ C-NMR for the polymer compound (8), the polymer composition (ratio (molar ratio) of each structural unit in the structural formula) was 1 / m / n = 45.0 / 44.9. /10.1. Moreover, the standard polystyrene conversion mass mean molecular weight calculated | required by GPC measurement was 8,400, and dispersion degree was 1.96.

[ Reference Example 1 , Examples 2 to 9, Comparative Example 1]
Each component shown in Table 1 was mixed and dissolved to prepare a positive resist composition.

In Table 1, the numerical values in [] indicate the blending amount (parts by mass). Moreover, the symbol in Table 1 shows the following, respectively.
(A) -1: polymer compound (1).
(A) -2: polymer compound (2).
(A) -3: polymer compound (3).
(A) -4: polymer compound (4).
(A) -5: polymer compound (5).
(A) -6: polymer compound (6).
(A) -7: polymer compound (7).
(A) -8: polymer compound (8).
(B) -1: An acid generator represented by the following chemical formula (B) -1.
(B) -2: An acid generator represented by the following chemical formula (B) -2.
(D) -1: tri-n-pentylamine.
(S) -1: PGMEA.
(S) -2: PGME.

  The acid generator (B) -1 is obtained by dissolving 6.99 g of triphenylsulfonium bromide in 125 ml of pure water, and adding 5.50 g of a lithium salt of 2-naphthylmethyloxytetrafluoroethanesulfonic acid to the solution, After stirring at room temperature for 19 hours, 125 g of dichloromethane was added and stirred, and the organic phase was separated and taken out. Further, the organic phase was washed with 40 ml of pure water and then separated, and the organic phase was taken out and taken out. It was obtained by concentrating and drying the organic phase.

  In the acid generator (B) -2, 4 g of (1-hydroxy-2,6-dimethylphenyl) diphenylsulfonium methanesulfonate was dissolved in dichloromethane (79.8 g). After confirmation of dissolution, potassium carbonate (6.87 g) was added, and 2-methyl-2-adamantane bromoacetate (3.42 g) was added. After reaction for 24 hours under reflux, filtration, washing with water were performed, and crystallization was performed with hexane. The obtained powder was dried under reduced pressure to obtain 3.98 g (yield 66%). Next, the obtained compound (4-2) (2.00 g) was dissolved in a mixed solution of water (10.00 g) and dichloromethane (10.00). Thereafter, lithium salt of 2-naphthylmethyloxytetrafluoroethanesulfonic acid (1.25 g) was added little by little and stirred at 25 ° C. for 1 hour. After completion of the reaction, the dichloromethane solution was washed with water and then concentrated to dryness. The obtained powder was dispersed and washed with hexane and then dried under reduced pressure.

Using the obtained resist composition, a resist pattern was formed by the following procedure, and the lithography characteristics were evaluated.
[Resolution and sensitivity]
An organic antireflection film composition “ARC29A” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto an 8-inch silicon wafer using a spinner, and baked at 205 ° C. for 60 seconds on a hot plate and dried. Thereby, an organic antireflection film having a thickness of 77 nm was formed. On the antireflection film, the resist compositions obtained above ( Reference Example 1 , Examples 2 to 5, Comparative Example 1) were respectively applied using a spinner, and 110 ° C. for 60 seconds on a hot plate. A pre-baking (PAB) process was performed under the conditions, and the resist film having a thickness of 120 nm was formed by drying.
Next, an ArF excimer laser (193 nm) was passed through a mask pattern (6% halftone) using an ArF exposure apparatus NSR-S302 (Nikon Corp .; NA (numerical aperture) = 0.60, 2/3 annular illumination). Selectively irradiated. Then, post-exposure heating (PEB) treatment was performed at 100 ° C. for 60 seconds, and further development was performed at 23 ° C. with a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution for 30 seconds, and then 30 Water rinsing was performed using pure water for 2 seconds, and then shaken off and dried.
As a result, in each example, a contact hole pattern having a diameter of 130 nm and a pitch of 260 nm was formed. The optimum exposure amount Eop (mJ / cm ² ) at this time, that is, the sensitivity was obtained. The results are shown in Table 2.

[Roundness]
The contact hole pattern having a diameter of 130 nm and a pitch of 260 nm formed above was observed from above using a scanning electron microscope SEM, and the roundness of the hole pattern was evaluated according to the following criteria. The results are shown in Table 2.
○: High roundness.
Δ: Low roundness.

As shown in the above results, each of the resist compositions of Reference Example 1 and Examples 2 to 5 was able to form a hole pattern with high roundness. The sensitivity (Eop) was also good, and among them, the sensitivity of Examples 2 to 4, particularly Example 4, was high.

[Resolution and sensitivity]
An organic antireflection film composition “ARC29A” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto an 8-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. Then, the positive resist compositions (Examples 6 to 8) obtained above were applied onto the antireflection film using a spinner, and pre-baked on a hot plate at 100 ° C. for 60 seconds ( A PAB) treatment was performed and dried to form a resist film having a thickness of 120 nm.
Next, a protective film-forming coating solution “TSRC-002” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied onto the resist film using a spinner and heated at 90 ° C. for 60 seconds. A top coat having a thickness of 28 nm was formed.
Next, a hole pattern was formed by an immersion ArF exposure apparatus NSR-S609B (Nikon Corporation; NA (numerical aperture) = 1.07, 2/3 annular illumination, reduction magnification 1/4, immersion medium: water). The resist film on which the top coat was formed was selectively irradiated with an ArF excimer laser (193 nm) through the mask.
The top coat was removed using a protective film removing solution “TS-Remover-S” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.), followed by PEB treatment at 95 ° C. for 60 seconds, and further at 23 ° C. Development was performed for 60 seconds with a 38 mass% TMAH aqueous solution NMD-W (manufactured by Tokyo Ohka Kogyo Co., Ltd.), followed by water rinsing with pure water for 30 seconds, followed by shake-off drying.
As a result, in each of the examples, a resist pattern of a hole pattern in which holes having a hole diameter (CD) of 70 nm are arranged at equal intervals (pitch 150 nm) was formed on the resist film.
At this time, the optimum exposure dose EOP (mJ / cm ² ) for forming a hole pattern with a diameter of 70 nm and a pitch of 150 nm was determined. The results are shown in Table 3.

[Roundness]
The contact hole pattern formed in the above with a diameter of 70 nm and a pitch of 150 nm was observed from above using a scanning electron microscope SEM, and the roundness of the hole pattern was evaluated according to the following criteria. The results are shown in Table 3.
○: High roundness.
Δ: Low roundness.

  As shown in the above results, each of the resist compositions of Examples 6 to 8 could form a hole pattern with high roundness. The sensitivity (Eop) was also good.

Claims (10)

A polymer compound having a structural unit (a1 ′) represented by the following general formula (a1′-1) and a structural unit (a3 ′) represented by the following general formula (a3′-1).

[In formula (a1′-1), R ¹ is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and A and B are each independently a divalent carbon atom which may have a substituent. A hydrogen group, n ₁ is 0 or 1, and R ² is an acid dissociable, dissolution inhibiting group. ]
[In Formula (a3′-1), R ³ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ⁴ represents an alkylene group, n ₄ represents 0 or 1, and n ₅ represents 0 to 0. 4, n ₆ is 0 or 1, n ₅ + n ₆ = 1 to 4, and R ₅ and R ₆ are each independently a hydrophilic group-containing substituent or a non-hydrophilic group-containing substituent. And at least one of R ₅ and R ₆ is a hydrophilic group-containing substituent. However, the case where the hydrophilic group-containing substituent is a hydroxyl group is excluded. ]   The polymer compound according to claim 1, wherein the hydrophilic group-containing substituent is selected from the group consisting of ═O, a hydroxyalkyl group, a hydroxyalkyloxy group, an alkyloxy group, and an alkyloxycarbonyloxy group.   The polymer compound according to claim 1, wherein the structural unit (a3 ′) is selected from the group consisting of structural units represented by the following general formulas (a3′-12) to (a3′-16).

[Wherein R ³ Is the same as above and R ⁵³ ~ R ⁵⁵ Are each independently a linear or branched alkyl group having 1 to 5 carbon atoms, and R ⁵⁶ ~ R ⁵⁷ Are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms; ⁶¹ ~ R ⁶² Are each independently a linear or branched alkylene group having 1 to 5 carbon atoms; ⁷¹ Is a C1-C5 linear or branched alkylene group. ] Furthermore, the high molecular compound as described in any one of Claims 1-3 which has a structural unit (a2) induced | guided | derived from the acrylate ester containing a lactone containing cyclic group. A positive resist composition comprising a base component (A) whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator component (B) that generates an acid upon exposure,
The base component (A) includes a structural unit (a1 ′) represented by the following general formula (a1′-1) and a structural unit (a3 ′) represented by the following general formula (a3′-1). A positive resist composition comprising a polymer compound (A1) having

[In formula (a1′-1), R ¹ is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and A and B are each independently a divalent carbon atom which may have a substituent. A hydrogen group, n ₁ is 0 or 1, and R ² is an acid dissociable, dissolution inhibiting group. ]
[In Formula (a3′-1), R ³ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ⁴ represents an alkylene group, n ₄ represents 0 or 1, and n ₅ represents 0 to 0. 4, n ₆ is 0 or 1, n ₅ + n ₆ = 1 to 4, and R ₅ and R ₆ are each independently a hydrophilic group-containing substituent or a non-hydrophilic group-containing substituent. And at least one of R ₅ and R ₆ is a hydrophilic group-containing substituent. However, the case where the hydrophilic group-containing substituent is a hydroxyl group is excluded. ]   The positive resist composition according to claim 5, wherein the hydrophilic group-containing substituent is selected from the group consisting of ═O, a hydroxyalkyl group, a hydroxyalkyloxy group, an alkyloxy group, and an alkyloxycarbonyloxy group.   The positive resist composition according to claim 5, wherein the structural unit (a3 ′) is selected from the group consisting of structural units represented by the following general formulas (a3′-12) to (a3′-16). object.

[Wherein R ³ Is the same as above and R ⁵³ ~ R ⁵⁵ Are each independently a linear or branched alkyl group having 1 to 5 carbon atoms, and R ⁵⁶ ~ R ⁵⁷ Are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 5 carbon atoms; ⁶¹ ~ R ⁶² Are each independently a linear or branched alkylene group having 1 to 5 carbon atoms; ⁷¹ Is a C1-C5 linear or branched alkylene group. ] The positive resist composition according to claim 5, wherein the polymer compound (A1) further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group. . The positive resist composition as described in any one of Claims 5-8 containing a nitrogen-containing organic compound (D). A step of forming a resist film on a support using the positive resist composition according to any one of claims 5 to 9 , 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.