JP2012073564A - Positive resist composition, resist pattern forming method, and polymer compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive resist composition capable of suppressing occurrence of defect after development and having good lithography characteristics and a good pattern shape, a resist pattern forming method, and a polymer compound.SOLUTION: A positive resist composition contains a base material component (A) whose solubility with respect to an alkali developer increases by action of an acid, and an acid generator component (B) which generates an acid by exposure. The base material component (A) contains a polymer compound (A1) having a constituent unit (a0) represented by a formula (a0-1) and a constituent unit (a1) represented by a formula (a1-1). With respect to the sum of all constituent units constituting the (A1), the ratio of the constituent unit (a0) is 10 to 60 mol%, the ratio of the constituent unit (a1) is 10 to 60 mol%, and the sum of these is 70 mol% or less.

Description

  The present invention relates to a positive resist composition that can suppress the occurrence of defects after development and has good lithography characteristics and pattern shape, a resist pattern forming method using the positive resist composition, and the positive resist composition It is related with a high molecular compound useful as.

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

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. As a result, the exposed area becomes soluble in an alkaline developer.
Currently, as a resist base resin used in ArF excimer laser lithography and the like, a resin having a constitutional unit derived from (meth) acrylic acid ester (acrylic resin) because of its excellent transparency near 193 nm ) Etc. are generally used (see, for example, Patent Document 1). Here, “(meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position. “(Meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position. “(Meth) acrylate” means one or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position.
The base resin generally contains a plurality of structural units 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.

  Currently, as a base resin for a chemically amplified resist, a resin containing a plurality of structural units is used in order to improve lithography properties and the like. For example, in the case of the positive type, it usually contains a structural unit having an acid dissociable, dissolution inhibiting group that is dissociated by the action of an acid generated from an acid generator, and further has a structural unit having a polar group such as a hydroxyl group, a lactone structure. The thing containing the structural unit which has is used. Among these, the structural unit having a lactone structure is generally considered to contribute to the improvement of lithography properties by improving the adhesion of the resist film to the substrate and improving the affinity with an alkali developer.

Further, in recent years, as a resist pattern having a high resolution of 0.15 microns or less is required, in addition to the above-described improvement in lithography characteristics, it is necessary to improve defects (surface defects) generated after development. It has become. This defect is a general defect detected when a developed resist pattern is observed from directly above with, for example, a surface defect observation apparatus (trade name “KLA”) manufactured by KLA Tencor. This defect is, for example, a scum after development, bubbles, dust, a bridge between resist patterns, and the like.
As a method for improving such defects, in the base resin, a method of reducing the proportion of structural units having a highly hydrophobic acid dissociable, dissolution inhibiting group, a method of increasing the proportion of structural units having a polar group, etc. Can be considered. As a defect improving method using the latter method, Patent Document 2 discloses a base resin having a structural unit having an oxo group (═O). Moreover, the thing of patent document 3 is also known as a base resin which has an oxo group.

JP 2003-241385 A International Publication No. 06/038477 Pamphlet JP 2001-188351 A

  Only the method of using a structural unit having a polar group in the base resin described in Patent Documents 2 to 3 has not yet provided a sufficient effect for improving defects. Therefore, in order to further improve the defect, it is necessary to reduce the proportion of the structural unit having an acid dissociable, dissolution inhibiting group. However, when the proportion of the structural unit having an acid dissociable, dissolution inhibiting group is lowered, there is a problem that the dissolution contrast is lowered, and the lithography properties and resolution are lowered, so that the lithography properties, resolution, and defect are improved. There is a need for a resist composition that satisfies the above requirements.

  Further, in the future, there is a demand for new materials that can be used for lithography applications as further advancement of lithography technology and expansion of application fields are expected. For example, as the miniaturization of patterns progresses, the resist material not only has resolution, but also various lithography characteristics such as depth of focus (DOF), and improvement in the shape of the obtained pattern. Desired.

  The present invention has been made in view of the above circumstances, and can use a positive resist composition that can suppress the occurrence of defects after development and has good lithography characteristics and pattern shape, and the positive resist composition. It is an object of the present invention to provide a resist pattern forming method and a polymer compound useful as the positive resist composition.

In order to solve the above problems, the present invention employs the following configuration.
That is, the first aspect of the present invention is a positive type containing a base component (A) whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator component (B) that generates an acid upon exposure. It is a resist composition, Comprising: The said base material component (A) is the structural unit (a1) represented by the structural unit (a0) represented by the following general formula (a0-1), and the following general formula (a1-1). And the proportion of the structural unit (a0) is 10 to 60 mol% with respect to the total of all the structural units constituting the polymer compound (A1). The positive resist composition is characterized in that the ratio of (a1) is 10 to 60 mol%, and the total of these is 70 mol% or less.

［式中、Ｒは水素原子、置換基を有していてもよい炭素数１〜４のアルキル基又はフッ素化アルキル基を表し；Ｒ^１は炭素数１〜５のアルキル基を表し、Ｙは２価の連結基を表し；Ｘは酸解離性溶解抑制基を表し；ｎ１は０〜５の整数を表し、ｎ２は０〜５の整数を表し、２≦ｎ１＋ｎ２≦８であり；ｌは０〜２の整数である。］

[Wherein, R represents a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms or a fluorinated alkyl group; R ¹ represents an alkyl group having 1 to 5 carbon atoms, and Y represents X represents an acid dissociable, dissolution inhibiting group; n1 represents an integer of 0 to 5, n2 represents an integer of 0 to 5, 2 ≦ n1 + n2 ≦ 8; It is an integer of ~ 2. ]

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

  A third aspect of the present invention is a polymer compound having a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) represented by the following general formula (a1-1). The ratio of the structural unit (a0) is 10 to 60 mol% and the ratio of the structural unit (a1) is 10 to 60 mol% with respect to the total of all the structural units constituting the polymer compound. The total is 70 mol% or less, and this is a polymer compound.

［式中、Ｒは水素原子、置換基を有していてもよい炭素数１〜４のアルキル基又はフッ素化アルキル基を表し；Ｒ^１は炭素数１〜５のアルキル基を表し、Ｙは２価の連結基を表し；Ｘは酸解離性溶解抑制基を表し；ｎ１は０〜５の整数を表し、ｎ２は０〜５の整数を表し、２≦ｎ１＋ｎ２≦８であり；ｌは０〜２の整数である。］

[Wherein, R represents a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms or a fluorinated alkyl group; R ¹ represents an alkyl group having 1 to 5 carbon atoms, and Y represents X represents an acid dissociable, dissolution inhibiting group; n1 represents an integer of 0 to 5, n2 represents an integer of 0 to 5, 2 ≦ n1 + n2 ≦ 8; It is an integer of ~ 2. ]

In the present specification and claims, “aliphatic” is a relative concept with respect to aromatics, and is defined to mean groups, compounds, etc. that do not have aromaticity.
The “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified.
Unless otherwise specified, the “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups. The same applies to the alkyl group in the alkoxy group.
The “halogenated alkyl group” is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
“Fluorinated alkyl group” or “fluorinated alkylene group” refers to a group in which part or all of the hydrogen atoms of an alkyl group or alkylene group are substituted with fluorine atoms.
“Structural unit” means a monomer unit (monomer unit) constituting a polymer compound (resin, polymer, copolymer).
“A structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
In the “acrylate ester in which an atom other than a hydrogen atom or a substituent may be bonded to a carbon atom at the α-position”, examples of the atom other than a hydrogen atom include a halogen atom, and the substituent includes 1 carbon atom. -5 alkyl groups, C1-C5 halogenated alkyl groups, hydroxyalkyl groups, and the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Note that the α-position (α-position carbon atom) of a structural unit derived from an acrylate ester means a carbon atom to which a carbonyl group is bonded, unless otherwise specified.
Specific examples of the alkyl group having 1 to 5 carbon atoms in the substituent which may be bonded to the α-position carbon atom include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, Examples include lower linear or branched alkyl groups such as tert-butyl group, pentyl group, isopentyl group, and neopentyl group.
Further, as the halogenated alkyl group having 1 to 5 carbon atoms in the substituent, a part or all of the hydrogen atoms in the above-mentioned “alkyl group having 1 to 5 carbon atoms in the substituent” are halogen atoms. And a 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.
Specific examples of the hydroxyalkyl group in the substituent include groups in which part or all of the hydrogen atoms in the above-mentioned “alkyl group having 1 to 5 carbon atoms in the substituent” are substituted with a hydroxy group. .
In the present invention, the bond to the carbon atom at the α-position is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. It is more preferably a C 1-5 alkyl group or a C 1-5 fluorinated alkyl group, and most preferably a hydrogen atom or a methyl group in terms of industrial availability.
“Exposure” is a concept including general irradiation of radiation.
“Degradable with respect to alkali developer” means that it is decomposed by the action of an alkali developer (preferably at 23 ° C. by the action of a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution. This means that the solubility in an alkaline developer is increased.

  According to the present invention, a positive resist composition that can suppress the occurrence of defects after development and has good lithography characteristics and pattern shape, a resist pattern forming method using the positive resist composition, and the positive resist A polymer compound useful as a composition can be provided.

≪Positive resist composition≫
The positive resist composition of the present invention comprises a base component (A) (hereinafter referred to as component (A)) whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator that generates an acid upon exposure. Contains component (B) (hereinafter referred to as component (B)).
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 alkali developer does not change, a resist pattern can be formed by performing alkali development.

<(A) component>
Here, “base material component” means an organic compound having film-forming ability.
As the base material component, an organic compound having a molecular weight of 500 or more is usually used. When the molecular weight is 500 or more, it has a sufficient film forming ability and can easily form a nano-level resist pattern.
“Organic compounds having a molecular weight of 500 or more” are roughly classified into non-polymers and polymers.
As the non-polymer, those having a molecular weight of 500 or more and less than 4000 are usually used. Hereinafter, the “low molecular compound” refers to a non-polymer having a molecular weight of 500 or more and less than 4000.
As the polymer, those having a molecular weight of 1000 or more are usually used. In the present specification and claims, “polymer compound” refers to a polymer having a molecular weight of 1000 or more.
In the case of a polymer compound, the “molecular weight” is a polystyrene-equivalent mass average molecular weight measured by GPC (gel permeation chromatography).

[Polymer Compound (A1)]
The polymer compound (A1) (hereinafter sometimes referred to as “component (A1)”) includes the structural unit (a0) represented by the general formula (a0-1) and the general formula (a1-1). And a structural unit (a1) represented by:
In addition to the structural units (a0) and (a1), the component (A1) is further derived from an acrylate ester in which an atom other than a hydrogen atom or a substituent may be bonded to the α-position carbon atom. It may have a structural unit (a2) that is a unit and contains a lactone-containing cyclic group.
In addition to the structural units (a0) and (a1) or in addition to the structural units (a0), (a1) and (a2), the component (A1) is further an atom other than a hydrogen atom on the α-position carbon atom. Alternatively, it may have a structural unit (a3) that is a structural unit derived from an acrylate ester to which a substituent may be bonded and that contains a polar group-containing aliphatic hydrocarbon group.

(Structural unit (a0))
The structural unit (a0) is a structural unit represented by the general formula (a0-1). By having an oxo group (═O), the resist film containing the structural unit (a0) is more preferably hydrophilized.
In formula (a0-1), R represents a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms, or an optionally substituted fluorinated alkyl group having 1 to 4 carbon atoms. It is a group.
Here, “may have a substituent” means that part or all of the hydrogen atoms in the alkyl group or fluorinated alkyl group may be substituted with groups or atoms other than hydrogen atoms. To do.
The alkyl group of R is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, Examples thereof include a tert-butyl group. The alkyl group of R may have a substituent. Examples of this substituent include halogen atoms other than fluorine atoms and hydroxy groups.
The fluorinated alkyl group for R is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 4 carbon atoms are substituted with fluorine atoms. The fluorinated alkyl group for R may have a substituent. Examples of this substituent include halogen atoms other than fluorine atoms and hydroxy groups.
Among these, R is most preferably a hydrogen atom or a methyl group because of industrial availability.

In formula (a0-1), R ¹ is an alkyl group having 1 to 5 carbon atoms.
The alkyl group having 1 to 5 carbon atoms of R ¹ is preferably a linear or branched alkyl group, and specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group. Tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like.
Among these, R ¹ is preferably an alkyl group having 2 or more carbon atoms, and is preferably an ethyl group or an isopropyl group because dissolution contrast is improved.

In formula (a0-1), n1 is an integer of 0 to 5, n2 is an integer of 0 to 5, and 2 ≦ n1 + n2 ≦ 8.
Especially, as n1 and n2, it is preferable that n1 + n2 is 3-6, it is more preferable that n1 + n2 is 3-5, and it is still more preferable that n1 and n2 are 2 or 3 each independently below Specific examples of the structural unit represented by the general formula (a0-1) are shown below.

As the structural unit (a0), one type may be used alone, or two or more types may be used in combination.
In the component (A1), the proportion of the structural unit (a0) is such that, when a resist pattern is formed using a positive resist composition containing the component (A1), the occurrence of defects, resolution, and resolution are formed. 10 to 60 mol with respect to all the structural units constituting the component (A1) because it is excellent in the shape of the resist pattern (for example, rectangular if it is a line pattern, roundness if it is a hole pattern), DOF, etc. %, Preferably 12 to 55 mol%, more preferably 15 to 50 mol%, still more preferably 20 to 45 mol%. By setting it as the said lower limit or more, a pattern can be easily obtained when it is set as a resist composition, and a balance with another structural unit can be taken by setting it as an upper limit or less.

  In the present invention, since the cyclic group in the structural unit (a0) is an acid dissociable, dissolution inhibiting group that can be dissociated by the action of an acid, the structural unit (a0) and the structural unit (a1) described later In the component (A1), the total is 70 mol% or less, preferably 20 to 70 mol%, more preferably 25 to 65 mol%, and further preferably 30 to 60 mol%. . By setting it to the above 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 (a1))
The structural unit (a1) is a structural unit represented by the general formula (a1-1).
In formula (a1-1), R is the same as R in formula (a0-1), and is preferably a hydrogen atom or a methyl group.
In formula (a1-1), l is an integer of 0 to 2, and is preferably 0 or 1.

In formula (a1-1), Y is a divalent linking group.
Preferred examples of the divalent linking group for Y include a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, and the like.
The term “having a substituent” for the hydrocarbon group means that part or all of the hydrogen atoms in the hydrocarbon group are substituted with groups or atoms other than hydrogen atoms.
The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

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

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

Examples of the aromatic hydrocarbon group in the hydrocarbon group of Y include monovalent groups such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. A divalent aromatic hydrocarbon group obtained by removing one more hydrogen atom from the aromatic hydrocarbon nucleus of the aromatic hydrocarbon group; a part of the carbon atoms constituting the ring of the divalent aromatic hydrocarbon group is Aromatic hydrocarbon groups substituted with heteroatoms such as oxygen, sulfur and nitrogen atoms; benzyl, phenethyl, 1-naphthylmethyl, 2-naphthylmethyl, 1-naphthylethyl and 2-naphthylethyl And an aromatic hydrocarbon group in which one hydrogen atom is further removed from the nucleus of the aromatic hydrocarbon.
The aromatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

The hetero atom in the “divalent linking group containing a hetero atom” of Y is an atom other than a carbon atom and a hydrogen atom, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom.
Specific examples of the divalent linking group containing a hetero atom include —O—, —C (═O) —, —C (═O) —O—, and a carbonate bond (—O—C (═O) —. O-), -NH-, ^-NR04 ( ^R04 is an alkyl group)-, -NH-C (= O)-, = N- and the like. Moreover, the combination etc. of these "divalent coupling groups containing a hetero atom" and a bivalent hydrocarbon group are mentioned. Examples of the divalent hydrocarbon group include the same hydrocarbon groups that may have a substituent as described above, and a linear or branched aliphatic hydrocarbon group is preferable.

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

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

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

In formula (a1-1), X is an acid dissociable, dissolution inhibiting group.
The acid dissociable, dissolution inhibiting group of X has an alkali dissolution inhibiting property that makes the entire component (A1) difficult to dissolve in an alkali developer before dissociation, and is dissociated by an acid to form an alkali of the entire component (A1). It is intended to increase the solubility in a developing solution, and it is possible to use those that have been proposed so far as acid dissociable, dissolution inhibiting groups for base resins for chemically amplified resists. In general, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like; an acetal-type acid dissociable, dissolution inhibiting group such as an alkoxyalkyl group is widely known. .

Here, the “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group in (meth) acrylic acid or the like with a chain or cyclic alkyl group, and the carbonyl A structure in which the tertiary carbon atom of the chain or cyclic alkyl group is bonded to the oxygen atom at the terminal of the oxy group (—C (O) —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 aliphatic branched acid dissociable, dissolution inhibiting groups and acid dissociable, dissolution inhibiting groups containing a cyclic group.
The cyclic group may be an aliphatic cyclic group or an aromatic cyclic group.

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

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the structural unit (a1) has 3 to 20 carbon atoms and may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like. Is mentioned.
The basic ring structure excluding the substituent of “aliphatic cyclic group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group, It is preferable that carbon number is 5-15.
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, tricyclos, which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group. Examples thereof include groups in which one or more hydrogen atoms have been removed from a polycycloalkane such as an alkane or tetracycloalkane. More specifically, 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 are exemplified. .
As an aromatic cyclic group, a C6-C20 aromatic cyclic group is mentioned, for example. Specific examples include groups in which one hydrogen atom has been removed from naphthalene, anthracene, phenanthrene, pyrene, and the like. Specific examples include 1-naphthyl group, 2-naphthyl group, 1-anthryl group, 2-anthryl group, 1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group, 1-pyrenyl group, and the like. A naphthyl group is particularly preferred industrially.

  Examples of the acid dissociable, dissolution inhibiting group containing a cyclic group include a group having a tertiary carbon atom on the ring skeleton of a cyclic alkyl group, specifically 2-methyl-2-adamantyl. Group, 2-ethyl-2-adamantyl group and the like. Alternatively, as shown by the following general formulas (a1 ″ -1) to (a1 ″ -9), an adamantyl group, a cyclohexyl group, a cyclopentyl group, a norbornyl group, a tricyclodecyl group, a tetracyclododecyl group, a naphthyl group, a phenyl group And a group having a cyclic alkylene group having a tertiary carbon atom bonded thereto.

［式中、Ｒ^１５、Ｒ^１６はアルキル基（直鎖状、分岐鎖状のいずれでもよく、好ましくは炭素数１〜５である）を示す。］

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

  The tertiary alkyl ester type acid dissociable, dissolution inhibiting group is preferably represented by the following formula (p0), more preferably represented by the following formula (p0-1).

［式中、ｍ_０は０または１であり、Ｒ^１３は水素原子またはメチル基であり、Ｒ^１４はアルキル基（直鎖状、分岐鎖状のいずれでもよく、好ましくは炭素数１〜５）であり、Ｒ^ｃは当該Ｒ^ｃが結合している炭素原子と共に脂肪族環式基を形成する基である。］

[Wherein, m ₀ is 0 or 1, R ¹³ is a hydrogen atom or a methyl group, and R ¹⁴ is an alkyl group (which may be linear or branched, and preferably has 1 to 5 carbon atoms). And R ^c is a group that forms an aliphatic cyclic group together with the carbon atom to which R ^c is bonded. ]

Examples of R ^c include the same as the above aliphatic cyclic group, and a polycyclic aliphatic cyclic group is preferable.

［式中、ｍ_０は０または１であり、Ｒ^１３は水素原子またはメチル基であり、Ｒ^１４はアルキル基（直鎖状、分岐鎖状のいずれでもよく、好ましくは炭素数１〜５）である。］

[Wherein, m ₀ is 0 or 1, R ¹³ is a hydrogen atom or a methyl group, and R ¹⁴ is an alkyl group (which may be linear or branched, and preferably has 1 to 5 carbon atoms). It is. ]

R ¹⁴ preferably has 1 to 3 carbon atoms, and more preferably a methyl group, an ethyl group, or an isopropyl group.

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

［式（ｐ１）中、Ｒ^１’，Ｒ^２’はそれぞれ独立して水素原子又は炭素数１〜５のアルキル基を表し、ｎは０〜３の整数を表し、Ｗは脂肪族環式基又は炭素原子数１〜５のアルキル基を表す。］

[In formula (p1), R ¹ ′ and R ² ′ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, n represents an integer of 0 to 3, and W represents an aliphatic cyclic group. Alternatively, it represents an alkyl group having 1 to 5 carbon atoms. ]

In the formula (p1), n represents an integer of 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
Examples of the alkyl group having 1 to 5 carbon atoms of R ¹ ′ and R ² ′ include the same as the alkyl group having 1 to 5 carbon atoms of R, preferably a methyl group or an ethyl group, and a methyl group is Most preferred.
In the present invention, it is preferable that at least one of R ¹ ′ and R ² ′ is a hydrogen atom. That is, the acid dissociable, dissolution inhibiting group (p1) is preferably an acetal type acid dissociable, dissolution inhibiting group represented by the following general formula (p1-1).

［式（ｐ１−１）中、Ｒ^１’、ｎ、Ｗはそれぞれ上記と同じである。］

[In formula (p1-1), R ¹ ′, n and W are the same as defined above. ]

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

  Preferable examples of the acetal type acid dissociable, dissolution inhibiting group represented by the general formula (p1-1) include those represented by the following formulas (11) to (24).

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

［式（ｐ２）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とＲ^１９とが結合して環を形成していてもよい。］

[In Formula (p2), R ¹⁷ and R ¹⁸ are each independently a linear or branched alkyl group or a hydrogen atom, and R ¹⁹ is a linear, branched or cyclic alkyl group. . Alternatively, R ¹⁷ and R ¹⁹ may each independently be a linear or branched alkylene group, and R ¹⁷ and 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 R ¹⁹ and R ¹⁷ are bonded to each other. It may be.
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.

  More specifically, examples of the structural unit (a1) include structural units represented by general formula (a1-0-1) shown below, structural units represented by general formula (a1-0-2) shown below, and the like. .

［式中、Ｒは前記と同様であり、Ｘ^１は酸解離性溶解抑制基を示し、Ｘ^２は酸解離性溶解抑制基を示し、Ｙ^２は２価の連結基を示す。］

[Wherein, R is as defined above, X ¹ represents an acid dissociable, dissolution inhibiting group, X ² represents an acid dissociable, dissolution inhibiting group, and Y ² represents a divalent linking group. ]

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

In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).
The divalent linking group for Y ² is the same as Y in the formula (a1-1).

  More specifically, examples of the structural unit (a1) include structural units represented by general formulas (a1-10) to (a1-40) shown below.

［式中、Ｒ、Ｒ^１’、Ｒ^２’、ｎ、ＷおよびＹはそれぞれ前記と同じであり、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す。］’

[Wherein, R, R ¹ ′, R ² ′, n, W and Y are the same as defined above, and X ′ represents a tertiary alkyl ester type acid dissociable, dissolution inhibiting group. ] '

In the formula, R is the same as described above.
X ′ is the same as the tertiary alkyl ester type acid dissociable, dissolution inhibiting group.
^{R 1 ', R 2',} n, as a W, 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, W The same thing is mentioned.
Examples of Y include the same as described above.
Specific examples of the structural units represented by the general formulas (a1-10) to (a1-40) are shown below.
In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
Among the above, the structural unit (a1) is preferably a structural unit represented by the general formula (a1-10) or (a1-30), specifically, the above formulas (a1-1-1) to (a1). -1-4), (a1-1-20) to (a1-1-23), and (a1-3-25) to (a1-3-32). More preferably, at least one kind is used.
Further, the structural unit (a1) is represented by the following general formula (a1-1-01) including the structural units represented by the formulas (a1-1-1) to (a1-1-3). , Formulas (a1-1-16) to (a1-1-17), (a1-1-20) to (a1-1-23), 02), those represented by the following general formula (a1-3-01) including the structural units represented by formulas (a1-3-25) to (a1-3-26), and formulas What is represented by the following general formula (a1-3-02) including the structural units represented by (a1-3-27) to (a1-3-28), formulas (a1-3-29) to ( What represented by the following general formula (a1-3-03) which includes the structural unit of a1-3-32) is preferable.

［式中、Ｒは水素原子、置換基を有していてもよい炭素数１〜４のアルキル基または炭素数１〜４のフッ素化アルキル基を示し、Ｒ^１１は炭素数１〜５のアルキル基を示し、Ｒ^１２は炭素数１〜５のアルキル基を示し、ｈは１〜６の整数を示す。］

[Wherein, R represents a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms or a fluorinated alkyl group having 1 to 4 carbon atoms, and R ¹¹ represents an alkyl group having 1 to 5 carbon atoms. R ¹² represents an alkyl group having 1 to 5 carbon atoms, and h represents an integer of 1 to 6. ]

In general formula (a1-1-01), R is the same as defined above.
Examples of the alkyl group for R ¹¹ include the same alkyl groups as those described above for R, and a methyl group, an ethyl group, or an isopropyl group is preferable.
In general formula (a1-1-02), R is the same as defined above.
Examples of the alkyl group for R ¹² include the same alkyl groups as those described above for R, and a methyl group, an ethyl group, or an isopropyl group is preferable.
h is preferably 1 or 2, and most preferably 2.

［式中、Ｒは水素原子、置換基を有していてもよい炭素数１〜４のアルキル基または炭素数１〜４のフッ素化アルキル基を示し；Ｒ^１４は炭素数１〜５のアルキル基であり、Ｒ^１３は水素原子またはメチル基であり、ａは１〜１０の整数であり、ｎ’は１〜６の整数である。］

[Wherein, R represents a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms or a fluorinated alkyl group having 1 to 4 carbon atoms; R ¹⁴ represents an alkyl having 1 to 5 carbon atoms; R ¹³ is a hydrogen atom or a methyl group, a is an integer of 1 to 10, and n ′ is an integer of 1 to 6. ]

In formula (a1-3-01) or (a1-3-02), R is the same as described above.
R ¹³ is preferably a hydrogen atom.
Alkyl group for R ¹⁴ is the same as ^{R 14} in the formula (p0) in a methyl group, an ethyl group or an isopropyl group.
a is preferably an integer of 1 to 8, particularly preferably an integer of 2 to 5, and most preferably 2.
n ′ is most preferably 1 or 2.

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

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

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

  In the component (A1), the proportion of the structural unit (a1) is 10 to 60 mol%, preferably 10 to 50 mol%, and preferably 10 to 40 mol% with respect to all the structural units constituting the component (A1). Is more preferable, and 12-36 mol% is further more preferable. By setting it to the lower limit value or more, a pattern can be easily obtained when the resist composition is used, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

(Structural unit (a2))
The structural unit (a2) is a structural unit derived from an acrylate ester in which an atom other than a hydrogen atom or a substituent may be bonded to a carbon atom at the α-position, and includes a lactone-containing cyclic group. is there.
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.
When the component (A1) is used for forming a resist film, the lactone cyclic group of the structural unit (a2) increases the adhesion of the resist film to the substrate or has an affinity for a developer containing water. It is effective in raising.
As the structural unit (a2), any unit can be used without any particular limitation.
Specifically, the lactone-containing monocyclic group is a group in which one hydrogen atom is removed from a 4- to 6-membered ring lactone, such as a group in which one hydrogen atom is removed from β-propiolactone, or γ-butyrolactone. Examples thereof include a group in which one hydrogen atom has been removed, and a group in which one hydrogen atom has been removed from δ-valerolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.
More specifically, examples of the structural unit (a2) include structural units represented by general formulas (a2-1) to (a2-5) shown below.

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

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

R in the general formulas (a2-1) to (a2-5) is the same as R in the structural unit (a0).
Examples of the alkyl group having 1 to 5 carbon atoms of R ′ include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group.
Examples of the alkoxy group having 1 to 5 carbon atoms of R ′ include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group.
R ′ is preferably a hydrogen atom in view of industrial availability.
The alkyl group in R ″ may be linear, branched or cyclic.
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom Or a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorinated alkyl group Specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Etc.
A ″ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (—O—) or a sulfur atom (—S—), an oxygen atom or a sulfur atom.
The alkylene group having 1 to 5 carbon atoms in A ″ is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, and the like. In the case of containing an oxygen atom or a sulfur atom, specific examples thereof include a group in which —O— or —S— is interposed between the terminal of the alkylene group or the carbon atom, such as —O—CH ₂ —, —CH. _{2 -O-CH 2 -, -} S-CH 2 -, - CH 2 -S-CH 2 - , and the like.
Among these, A ″ is preferably an alkylene group having 1 to 5 carbon atoms, an oxygen atom (—O—) or a sulfur atom (—S—), and an alkylene group having 1 to 5 carbon atoms or —O—. The alkylene group having 1 to 5 carbon atoms is more preferably a methylene group or a dimethylmethylene group, and most preferably a methylene group.

R ²⁹ is a single bond or a divalent linking group. As a bivalent coupling group, the thing similar to the bivalent coupling group demonstrated by Y in the said general formula (a1-1) is mentioned. Among these, an alkylene group, an ester bond (—C (═O) —O—), or a combination thereof is preferable. The alkylene group as the divalent linking group for R ²⁹ is more preferably a linear or branched alkylene group. Specific examples include the same linear alkylene groups and branched alkylene groups as the aliphatic hydrocarbon groups for Y.
As R ²⁹ , in particular, a single bond or —R ²⁹ ′ —C (═O) —O— [wherein R ²⁹ ′ is a linear or branched alkylene group. ] Is preferable.
The linear or branched alkylene group for R ²⁹ ′ preferably has 1 to 10 carbon atoms, more preferably 1 to 8, still more preferably 1 to 5, particularly preferably 1 to 3. ~ 2 is most preferred.
As the linear alkylene group for R ²⁹ ′, a methylene group or an ethylene group is preferable, and a methylene group is particularly preferable. The branched alkylene group for R ²⁹ ′ is preferably an alkylmethylene group or an alkylethylene group, and —CH (CH ₃ ) —, —C (CH ₃ ) ₂ — or —C (CH ₃ ) ₂ CH ₂ — Is particularly preferred.
In formula (a2-1), s ″ is preferably 1 to 2.
Specific examples of the structural units represented by the general formulas (a2-1) to (a2-5) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

In the component (A1), as the structural unit (a2), one type may be used alone, or two or more types may be used in combination.
In the present invention, when the component (A1) has the structural unit (a2), the structural unit (a2) is composed of the structural unit represented by any one of the general formulas (a2-1) to (a2-5). It is preferable to have at least one selected from the group, and at least one selected from the group consisting of structural units represented by any one of the general formulas (a2-1) to (a2-3) is more It is particularly preferable to have at least one selected from the group consisting of structural units represented by the general formula (a2-1) or (a2-2).

  When the component (A1) has the structural unit (a2), the proportion of the structural unit (a2) in the component (A1) is such that the resist film formed using the positive resist composition containing the component (A1) It is preferable that it is 5 to 70 mol% or more with respect to the total of all the structural units constituting the component (A1), because of its excellent adhesion to a support such as a substrate, affinity with a developer, and the like. 10-65 mol% is more preferable, 15-65 mol% is further more preferable, and 20-60 mol% is the most preferable. By setting it as the above range, MEF and pattern shape are further improved, and CDU is also improved.

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

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

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

[Wherein, R is as defined above, j is an integer of 1 to 3, k is an integer of 1 to 3, t ′ is an integer of 1 to 3, and l is an integer of 1 to 5] And s is an integer of 1 to 3. ]

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

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

  In formula (a3-3), t ′ is preferably 1. l is preferably 1. s is preferably 1. In these, a 2-norbornyl group or a 3-norbornyl group is preferably 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.
When the component (A1) has the structural unit (a3), the proportion of the structural unit (a3) in the component (A1) is 1 to 50 mol% with respect to all the structural units constituting the component (A1). It is preferably 3 to 45 mol%, more preferably 5 to 40 mol%. By setting it to the lower limit value or more, the effect of containing the structural unit (a3) can be sufficiently obtained, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

(Other structural units)
The component (A1) includes other structural units (hereinafter referred to as structural unit (a4)) other than the structural units (a0) and (a1) to (a3) as long as the effects of the present invention are not impaired. May be.
The structural unit (a4) is not particularly limited as long as it is another structural unit not classified into the structural units (a0) and (a1) to (a3) described above, and is for ArF excimer laser, for KrF excimer laser, Many things conventionally known as what is used for resist resin for EUV, EB, etc. can be used.
Examples of the structural unit (a4) include a structural unit derived from an acrylate ester containing a non-acid dissociable aliphatic polycyclic group, a structural unit derived from a styrene monomer, and a vinyl naphthalene monomer. preferable.
Examples of the non-acid-dissociable aliphatic polycyclic group include those exemplified for the structural unit (a1), for ArF excimer laser, KrF excimer laser ( A number of hitherto known materials can be used as the resin component of the resist composition (preferably for ArF excimer laser).
In particular, at least one selected from a tricyclodecanyl group, an adamantyl group, a tetracyclododecanyl group, an isobornyl group, and a norbornyl group is preferable in terms of industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include those represented by the following general formulas (a4-1) to (a4-5).

［式中、Ｒは前記と同じである。］

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

As the structural unit (a4), one type may be used alone, or two or more types may be used in combination.
When the structural unit (a4) is contained in the component (A1), the proportion of the structural unit (a4) is preferably 1 to 20 mol% with respect to the total of all the structural units constituting the component (A1). 15 mol% is more preferable and 1-10 mol% is further more preferable.

The component (A1) is a copolymer having the structural units (a0) and (a1).
Examples of such a copolymer include: a copolymer composed of structural units (a0) and (a1); a copolymer composed of structural units (a0), (a1) and (a3); a structural unit (a0), ( a1), a copolymer composed of (a2) and (a3); a copolymer composed of structural units (a0), (a1) and (a2); a structural unit (a0), (a1), (a2), ( Examples thereof include a copolymer comprising a3) and (a4).
In the present invention, the component (A1) preferably includes a combination of structural units represented by the following general formulas (A1-11) to (A1-12). In the following formulas, R, R ¹ , R ¹¹ , R ¹² , R ²⁹ , s ″, h, j, n1, and n2 are the same as described above, and a plurality of Rs in the formula are the same as May be different

The mass average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, preferably 1000 to 50000, more preferably 1500 to 30000, most preferably 2500 to 20000. preferable. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is above the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Further, the dispersity (Mw / Mn) of the component (A1) is not particularly limited, and is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and 1.2 to 2 .5 is most preferred.
In addition, Mn shows a number average molecular weight.

The component (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).
Further, for the component (A1), in the polymerization, a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination, so that the terminal A —C (CF ₃ ) ₂ —OH group may be introduced into the. As described above, a copolymer introduced with a hydroxyalkyl group in which a part of hydrogen atoms of the alkyl group is substituted with a fluorine atom reduces development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing
A commercially available monomer may be used as the monomer for deriving each structural unit, or the monomer may be synthesized using a known method.
The structure of a compound synthesized using a known method 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 It can be confirmed by a general organic analysis method such as analysis (MS) method, elemental analysis method or X-ray crystal diffraction method.

In the component (A), as the component (A1), one type may be used alone, or two or more types may be used in combination.
The proportion of the component (A1) in the component (A) is preferably 25% by mass or more, more preferably 50% by mass, further preferably 75% by mass, and 100% by mass with respect to the total mass of the component (A). May be. When the ratio is 25% by mass or more, effects such as lithography characteristics are improved.

The positive resist composition of the present invention does not correspond to the component (A1) as the component (A), but is a base material component (hereinafter referred to as “component (A2)”) that increases the solubility in an alkaline developer by the action of an acid. .) May be contained.
The component (A2) is 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 ArF) A base resin such as for excimer laser) may be arbitrarily selected and used. For example, the base resin for ArF excimer laser includes a resin having the structural unit (a1) as an essential structural unit and optionally further including the structural units (a2) to (a4). Moreover, you may contain the nonpolymer (low molecular compound) whose molecular weight is 500-4000.
(A2) A component may be used individually by 1 type and may be used in combination of 2 or more type.

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

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

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

[Wherein, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group; among R ¹ ″ to R ³ ″ in formula (b-1), Any two may be bonded to each other to form a ring together with the sulfur atom in the formula; R ⁴ ″ may be an optionally substituted alkyl group, halogenated alkyl group, aryl group, or alkenyl group; 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 for the hydrogen atom of the aryl group is preferably a fluorine atom.

The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, linear C1-10, branched or cyclic alkyl group, and the like. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decyl 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 ″.

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

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

Examples of the substituent include a halogen atom, a hetero atom, an alkyl group, and a formula: X ⁰¹ -Q ^1- [wherein Q ¹ is a divalent linking group containing an oxygen atom, and X ⁰¹ represents a substituent. It is a C3-C30 hydrocarbon group which may have. ] 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 X ⁰¹ -Q ^1- , Q ¹ is a divalent linking group containing an oxygen atom.
Q ¹ may contain an atom other than an oxygen atom. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, oxygen atoms, sulfur atoms, and nitrogen atoms.
Examples of the divalent linking group containing an oxygen atom include an oxygen atom (ether bond; —O—), an ester bond (—C (═O) —O—), and an amide bond (—C (═O) —NH. -), A carbonyl group (-C (= O)-), a non-hydrocarbon oxygen atom-containing linking group such as a carbonate bond (-O-C (= O) -O-); the non-hydrocarbon oxygen atom Examples include a combination of a containing linking group and an alkylene group.
Examples of the combination include —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) —O—R ⁹³ —O—C (═O) — , R ^{91 to} R ⁹³ are each independently an alkylene group.) And the like.
The alkylene group in R ^{91 to} R ⁹³ is preferably a linear or branched alkylene group, and the alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. preferable.
Specific examples of the alkylene group include a methylene group [—CH ₂ —]; —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ) ₂ —, —C ( _{CH 3) (CH 2 CH 3} ) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as ethylene group _[-CH 2 CH _2— ]; —CH (CH ₃ ) CH ₂ —, —CH (CH ₃ ) CH (CH ₃ ) —, —C (CH ₃ ) ₂ CH ₂ —, —CH (CH ₂ CH ₃ ) CH ₂ — and the like. Alkylethylene groups; trimethylene groups (n-propylene groups) [—CH ₂ CH ₂ CH ₂ —]; alkyls such as —CH (CH ₃ ) CH ₂ CH ₂ — and —CH ₂ CH (CH ₃ ) CH ₂ — trimethylene; tetramethylene group _[-CH 2 _CH 2 C _{2 CH 2 -]; - CH} (CH 3) CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 CH 2 - alkyl tetramethylene group and the like; pentamethylene group _[-CH 2 _CH 2 CH ₂ CH ₂ CH ₂ —] and the like.
Q ¹ is preferably a divalent linking group containing an ester bond or an ether bond, and among them, —R ⁹¹ —O—, —R ⁹² —O—C (═O) — or —C (═O) — O—R ⁹³ —O—C (═O) — is preferred.

In the group represented by X ⁰¹ -Q ^1- , the hydrocarbon group of X ⁰¹ may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.
The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and most preferably 6 to 12. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic hydrocarbon group include a hydrogen atom from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Aryl groups such as aryl group, benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., from which one is removed. The number of carbon atoms in the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.
The aromatic hydrocarbon group may have a substituent. For example, a part of carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group may be substituted with a hetero atom, and the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group is substituted with the substituent. May be.
Examples of the former include heteroaryl groups in which some of the carbon atoms constituting the ring of the aryl group are substituted with heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and aromatic hydrocarbons in the arylalkyl groups. Examples include heteroarylalkyl groups in which some of the carbon atoms constituting the ring are substituted with the above heteroatoms.
Examples of the substituent of the aromatic hydrocarbon group in the latter example include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group as a substituent of the aromatic hydrocarbon group is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. preferable.
The alkoxy group as a substituent of the aromatic hydrocarbon group is preferably an alkoxy group having 1 to 5 carbon atoms, and is a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, tert- A butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent of the aromatic hydrocarbon group include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

The aliphatic hydrocarbon group for X ⁰¹ may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
In X ⁰¹ , the aliphatic hydrocarbon group may have a part of the carbon atoms constituting the aliphatic hydrocarbon group substituted with a substituent containing a heteroatom, and the hydrogen constituting the aliphatic hydrocarbon group A part or all of the atoms may be substituted with a substituent containing a hetero atom.
The “hetero atom” in X ⁰¹ is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The substituent containing a hetero atom may be composed of only the hetero atom, or may be a group containing a group or atom other than the hetero atom.
Specific examples of the substituent for substituting a part of the carbon atom include —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O. —, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group, an acyl group, etc.), —S—, —S (═O) ₂ —, — S (= O) ₂ —O— and the like can be mentioned. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent for substituting part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and a cyano group.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.

Examples of the aliphatic hydrocarbon group include a linear or branched saturated hydrocarbon group, a linear or branched monovalent unsaturated hydrocarbon group, or a cyclic aliphatic hydrocarbon group (aliphatic ring). Formula group) is preferred.
The linear saturated hydrocarbon group (alkyl group) preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group and the like.
The branched saturated hydrocarbon group (alkyl group) preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, Examples include 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.

As an unsaturated hydrocarbon group, it is preferable that carbon number is 2-10, 2-5 are preferable, 2-4 are preferable, and 3 is especially preferable. Examples of the linear monovalent unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched monovalent unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group.
Among the above, the unsaturated hydrocarbon group is particularly preferably a propenyl group.

The aliphatic cyclic group may be a monocyclic group or a polycyclic group. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12.
Specifically, for example, a group in which one or more hydrogen atoms are removed from a monocycloalkane; a group in which one or more hydrogen atoms are removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
When the aliphatic cyclic group does not contain a substituent containing a hetero atom in the ring structure, the aliphatic cyclic group is preferably a polycyclic group, and has one or more hydrogen atoms from the polycycloalkane. Excluded groups are preferred, and most preferred are groups in which one or more hydrogen atoms have been removed from adamantane.
When the aliphatic cyclic group includes a substituent containing a hetero atom in the ring structure, examples of the substituent containing a hetero atom include —O—, —C (═O) —O—, —S—. , —S (═O) ₂ — and —S (═O) ₂ —O— are preferable. Specific examples of the aliphatic cyclic group include the following formulas (L1) to (L6), (S1) to (S4), and the like.

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

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

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

In the present invention, X ⁰¹ is preferably a cyclic group which may have a substituent. The cyclic group may be an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a substituent. It is preferably an aliphatic cyclic group that may be used.
The aromatic hydrocarbon group is preferably a naphthyl group which may have a substituent or a phenyl group which may have a substituent.
As the aliphatic cyclic group which may have a substituent, a polycyclic aliphatic cyclic group which may have a substituent is preferable. The polycyclic aliphatic cyclic group is preferably a group obtained by removing one or more hydrogen atoms from the polycycloalkane, the above (L2) to (L5), (S3) to (S4), and the like.

In the present invention, R ⁴ ″ preferably has X ⁰¹ -Q ^1- as a substituent. In this case, R ⁴ ″ has X ⁰¹ -Q ¹ -Y ^1- [wherein Q ¹ and X ^{1 01} is the same as above, and Y ¹ is an optionally substituted alkylene group having 1 to 4 carbon atoms or an optionally substituted fluorinated alkylene group having 1 to 4 carbon atoms. . ] Is preferable.
In the group represented by X ⁰¹ -Q ¹ -Y ^1- , examples of the alkylene group for Y ¹ include the same alkylene groups as those described above for Q ¹ having 1 to 4 carbon atoms.
Examples of the fluorinated alkylene group include groups in which part or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms.
As Y ^1, _{specifically, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF (CF 2 CF 3) -, _{-C (CF 3) 2 -,} - CF 2 CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF ₃ ) —, —C (CF ₃ ) ₂ CF ₂ —, —CF (CF ₂ CF ₃ ) CF ₂ —, —CF (CF ₂ CF ₂ CF ₃ ) —, —C (CF ₃ ) (CF _{2 CF 3) -; - CHF} -, - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -, - CH (CF 3) CH 2 -, - CH (CF 2 _{CF 3) -, - C (} CH 3) (CF 3) -, - CH 2 CH 2 CH 2 CF 2 -, - C H ₂ CH ₂ CF ₂ CF ₂ —, —CH (CF ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CF ₃ ) CH ₂ —, —CH (CF ₃ ) CH (CF ₃ ) —, —C ( _{CF 3) 2 CH 2 -;} - CH 2 -, - CH 2 CH 2 -, - CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 -, - CH (CH 2 CH 3) -, - _{C (CH 3) 2 -,} - CH 2 CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 -, - CH (CH 3) CH _{(CH 3) -, - C} (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - CH (CH 2 CH 2 CH 3) -, - C (CH 3) (CH 2 CH ₃ ) — and the like.

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

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

In formula (b-2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group. At least one of R ⁵ ″ to R ⁶ ″ represents an aryl group. It is preferable that all of R ⁵ ″ to R ⁶ ″ are aryl groups.
As the aryl group for R ⁵ ″ to R ⁶ ″, the same as the aryl groups for R ¹ ″ to R ³ ″ can be used.
Examples of the alkyl group for R ⁵ ″ to R ⁶ ″ include the same as the alkyl group for R ¹ ″ to R ³ ″.
Among these, it is most preferable that R ⁵ ″ to R ⁶ ″ are all phenyl groups.
"The, ^{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, the anion part of these onium salts is an alkyl sulfonate such as methanesulfonate, n-propanesulfonate, n-butanesulfonate, n-octanesulfonate, 1-adamantanesulfonate, 2-norbornanesulfonate, d-camphor-10-sulfonate, An onium salt substituted with an aromatic sulfonate such as benzene sulfonate, perfluorobenzene sulfonate, or p-toluene sulfonate can also be used.

  Moreover, the onium salt which replaced the anion part of these onium salts by the anion part represented by either of following formula (b1)-(b8) can also be used.

［式中、ｐは１〜３の整数であり、ｑ１〜ｑ２はそれぞれ独立に１〜５の整数であり、ｑ３は１〜１２の整数であり、ｔ３は１〜３の整数であり、ｒ１〜ｒ２はそれぞれ独立に０〜３の整数であり、ｇは１〜２０の整数であり、Ｒ^７は置換基であり、ｎ１’〜ｎ５’はそれぞれ独立に０または１であり、ｖ０〜ｖ５はそれぞれ独立に０〜３の整数であり、ｗ１〜ｗ５はそれぞれ独立に０〜３の整数であり、Ｑ”は前記と同じである。］

[Wherein p is an integer of 1 to 3, q1 to q2 are each independently an integer of 1 to 5, q3 is an integer of 1 to 12, t3 is an integer of 1 to 3, and r1 ~r2 are each independently an integer of 0 to 3, g is an integer of 1 to 20, ^{R 7} is a substituent, n1'~n5 'are each independently 0 or 1, v0~v5 Are each independently an integer of 0 to 3, w1 to w5 are each independently an integer of 0 to 3, and Q ″ is the same as above.]

Examples of the substituent for R ⁷ are the same as those described above as the substituent that the aliphatic hydrocarbon group may have and the substituent that the aromatic hydrocarbon group may have in X ⁰¹ . Is mentioned.
Code (r1 and r2, w1 to w5) attached to R ⁷ when is an integer of 2 or more, a plurality of the ^{R 7} groups may be the same, respectively, may be different.

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

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

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

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

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

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

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

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

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

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

［式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。］

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

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

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

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

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

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

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

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

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

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Further, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [Chemical 18] to [Chemical 19]), pamphlet of International Publication No. 04/074242, An oxime sulfonate-based acid generator disclosed in Examples 1 to 40) on pages 65 to 86 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

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

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

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

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

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

The positive resist composition of the present invention can be produced by dissolving the material in an organic solvent (hereinafter sometimes referred to as (S) component).
As the component (S), any component can be used as long as it can dissolve each component to be used to form a uniform solution. Conventionally, any one of known solvents for chemically amplified resists can be used. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone; many such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol Monohydric alcohols; compounds having an ester bond, such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, monomethyl ether, monoethyl of the polyhydric alcohols or compound having the ester bond Ethers such as ether, monopropyl ether, monobutyl ether and other monoalkyl ethers and monophenyl ether Derivatives of polyhydric alcohols such as compounds having a combination [in these, propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred]; cyclic ethers such as dioxane, methyl lactate Esters such as ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether , Dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. Examples of the solvent include dimethyl sulfoxide (DMSO).
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.
(S) The usage-amount of a component is not specifically limited, It is a density | concentration which can be apply | coated to a board | substrate etc., and is suitably set according to a coating film thickness. Generally, it is used so that the solid content concentration of the resist composition is in the range of 1 to 20% by mass, preferably 2 to 15% by mass.

According to the present invention, it is possible to obtain a positive resist composition that can suppress the occurrence of defects after development and has good lithography characteristics and pattern shape.
The reason why the above effect is obtained is not clear, but it is considered that the component (A) contains the structural unit (a0) having an acid dissociable, dissolution inhibiting group and an oxo group.
First, in the present invention, since the structural unit (a0) has an acid dissociable, dissolution inhibiting group in addition to the structural unit (a1), the component (A) has a relatively large number of acid dissociable, dissolution inhibiting groups. Therefore, the acid generated from the component (B) in the exposed part dissociates a relatively large amount of acid dissociable, dissolution inhibiting group, and the solubility of the exposed part is preferably increased. Therefore, it is considered that the above-described good lithography characteristics and a good pattern shape can be obtained.

In addition, since the structural unit (a0) has an oxo group that is a polar group at the same time, it is presumed that the hydrophilicity of the resist film surface formed in the unexposed portion is increased and defects can be reduced. By increasing the hydrophilicity of the resist film surface, for example, when rinsing with water after development, components such as a base resin dissolved in an alkaline developer are re-precipitated, and this adheres to the highly hydrophobic resist pattern surface. It is speculated that the occurrence of defects can be suppressed.
Conventionally, it has been known that, for example, when a structural unit containing a hydrophilic group such as a hydroxyl group is introduced into a base resin, the hydrophilicity of the entire resist composition is increased and the above-described defects can be reduced. However, when the proportion of the structural unit containing a hydrophilic group in the base resin is increased, there is a problem in that sufficient lithography characteristics cannot be obtained because the proportion of other structural units is generally relatively low. The present invention is considered to improve this problem by using the structural unit (a0) having an acid dissociable, dissolution inhibiting group and an oxo group.

The hydrophobicity and hydrophilicity of the resist film are determined by the contact angle with water, for example, the static contact angle (the angle between the surface of the water droplet on the resist film in the horizontal state and the resist film surface), the dynamic contact angle (the resist film The contact angle (falling angle) when the water droplet starts to fall when tilted, the contact angle (forward angle) at the front end point of the water drop direction, and the contact angle (backward angle) at the end point behind the falling direction It can be evaluated by measuring. For example, the higher the hydrophobicity of the resist film, the larger the static contact angle, advancing angle, and receding angle, while the falling angle becomes smaller.
The above-mentioned various angles (dynamic contact angle (advance angle, receding angle, sliding angle, etc.), static contact angle) are DROP MASTER-700 (product name, manufactured by Kyowa Interface Science Co., Ltd.), AUTO SLIDING ANGLE: SA-30DM. (Product name, manufactured by Kyowa Interface Science Co., Ltd.), AUTO DISPENSER: AD-31 (product name, manufactured by Kyowa Interface Science Co., Ltd.) and the like can be used for measurement.

≪Resist pattern formation method≫
The resist pattern forming method of the present invention comprises a step of forming a resist film on a support using the positive resist composition of the present invention, a step of exposing the resist film, and developing the resist film to form a resist. Forming a pattern.
The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, first, the resist composition is coated on a support with a spinner or the like, and pre-baked (post-apply bake (PAB)) for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150 ° C. For example, an exposure apparatus such as an ArF exposure apparatus, an electron beam drawing apparatus, or an EUV exposure apparatus is used for exposure through a mask (mask pattern) on which a predetermined pattern is formed, or an electron beam that does not pass through the mask pattern. After selective exposure by direct irradiation or the like, PEB (post-exposure heating) is applied for 40 to 120 seconds, preferably 60 to 90 seconds under a temperature condition of 80 to 150 ° C. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide (TMAH), preferably rinsed with pure water and dried. In some cases, a baking process (post-bake) may be performed after the development process.
In this way, a resist pattern faithful to the mask pattern can be obtained.

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

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 highly useful for KrF excimer laser, ArF excimer laser, EB or EUV, and is particularly useful for ArF excimer laser.

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

≪Polymer compound≫
The polymer compound of the present invention is a polymer compound having a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) represented by the following general formula (a1-1). The ratio of the structural unit (a0) is 10 to 60 mol% and the ratio of the structural unit (a1) is 10 to 60 mol% with respect to the total of all the structural units constituting the polymer compound. The total of these is 70 mol% or less.
The description of the polymer compound of the present invention is the same as the description of the component (A1) of the resist composition of the present invention.

［式中、Ｒは水素原子、置換基を有していてもよい炭素数１〜４のアルキル基又はフッ素化アルキル基を表し；Ｒ^１は炭素数１〜５のアルキル基を表し、Ｙは２価の連結基を表し；Ｘは酸解離性溶解抑制基を表し；ｎ１は０〜５の整数を表し、ｎ２は０〜５の整数を表し、２≦ｎ１＋ｎ２≦８であり；ｌは０〜２の整数である。］

[Wherein, R represents a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms or a fluorinated alkyl group; R ¹ represents an alkyl group having 1 to 5 carbon atoms, and Y represents X represents an acid dissociable, dissolution inhibiting group; n1 represents an integer of 0 to 5, n2 represents an integer of 0 to 5, 2 ≦ n1 + n2 ≦ 8; It is an integer of ~ 2. ]

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.

[Examples 1 to 4, Comparative Examples 1 to 6]
Each component shown in Table 1 was mixed and dissolved to prepare a positive resist composition.

In Table 1, the numerical value in [] shows a compounding quantity (part by mass). Moreover, the symbol in Table 1 shows the following, respectively.
(A) -1: the following polymer compound (A) -1.
(A) -2: the following polymer compound (A) -2.
(A) -3: The following polymer compound (A) -3.
(A) -4: The following polymer compound (A) -4.
(A) -5: The following polymer compound (A) -5.
(A) -6: The following polymer compound (A) -6.
(A) -7: The following polymer compound (A) -7.
(A) -8: The following polymer compound (A) -8.
(A) -9: the following polymer compound (A) -9.
(A) -10: the following polymer compound (A) -10.
(B) -1: The following compound (B) -1.
(D) -1: tri-n-octylamine.
(E) -1: salicylic acid.
(S) -1: Mixed solvent of PGMEA / PGME = 30/20 (mass ratio).

［ｌ／ｍ／ｎ／ｏ＝２６／３５／２０／１９、Ｍｗ＝７７００、Ｍｗ／Ｍｎ＝１．６２］

[1 / m / n / o = 26/35/20/19, Mw = 7700, Mw / Mn = 1.62]

［ｌ／ｍ／ｎ／ｏ＝２５／１５／４０／２０、Ｍｗ＝７５００、Ｍｗ／Ｍｎ＝１．６３］

[L / m / n / o = 25/15/40/20, Mw = 7500, Mw / Mn = 1.63]

［ｌ／ｍ／ｎ／ｏ＝２６／１３／４０／２１、Ｍｗ＝６８００、Ｍｗ／Ｍｎ＝１．６４］

[1 / m / n / o = 26/13/40/21, Mw = 6800, Mw / Mn = 1.64]

［ｌ／ｍ／ｎ／ｏ＝２６／３５／２０／１９、Ｍｗ＝８０００、Ｍｗ／Ｍｎ＝１．６１］

[1 / m / n / o = 26/35/20/19, Mw = 8000, Mw / Mn = 1.61]

［ｌ／ｍ／ｎ／ｏ＝２４／１３／４２／２１、Ｍｗ＝７５００、Ｍｗ／Ｍｎ＝１．５０］

[1 / m / n / o = 24/13/42/21, Mw = 7500, Mw / Mn = 1.50]

［ｌ／ｍ／ｎ＝４０／４０／２０、Ｍｗ＝７０００、Ｍｗ／Ｍｎ＝１．６０］

[1 / m / n = 40/40/20, Mw = 7000, Mw / Mn = 1.60]

［ｌ／ｍ／ｎ＝２５／５５／２０、Ｍｗ＝７５００、Ｍｗ／Ｍｎ＝１．６２］

[L / m / n = 25/55/20, Mw = 7500, Mw / Mn = 1.62]

［ｌ／ｍ／ｎ＝４０／４０／２０、Ｍｗ＝１０１００、Ｍｗ／Ｍｎ＝１．６２］

[1 / m / n = 40/40/20, Mw = 10100, Mw / Mn = 1.62]

［ｌ／ｍ／ｎ＝２５／５５／２０、Ｍｗ＝８６００、Ｍｗ／Ｍｎ＝１．５９］

[L / m / n = 25/55/20, Mw = 8600, Mw / Mn = 1.59]

［ｌ／ｍ／ｎ／ｏ＝２４／１５／４２／１９、Ｍｗ＝６８００、Ｍｗ／Ｍｎ＝１．６３］

[1 / m / n / o = 24/15/42/19, Mw = 6800, Mw / Mn = 1.63]

<Formation of resist pattern>
[Optimum exposure and resolution]
An organic antireflection film composition “ARC29SR” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto a 12-inch silicon wafer using a spinner, and baked on a hot plate at 205 ° C. for 60 seconds to be dried. Thus, an organic antireflection film having a film thickness of 85 nm was formed.
The positive resist composition of each example was applied onto the organic antireflection film using a spinner, and prebaked (PAB) treatment was performed on a hot plate at 115 ° C. for 60 seconds. A film thickness of 250 nm) was formed.
The formed resist film is exposed through a mask pattern using an ArF exposure apparatus S-302 (manufactured by Nikon; NA (numerical aperture) = 0.75; σ0.60) at 110 ° C. A baking process (PEB) for 60 seconds was performed. Thereafter, development was further performed at 23 ° C. using a 2.38% by weight aqueous solution of TMAH (trade name: NMD-3, manufactured by Tokyo Ohka Kogyo Co., Ltd.), followed by rinsing with pure water for 15 seconds. A line and space (L / S) pattern was formed.
At this time, the optimum exposure amount (Eop; mJ / cm ² ) at which a 140 nm L / S pattern was formed at 1: 1 was determined. The results are shown in Table 2.
Further, the limit resolution (nm) in the Eop was determined using a scanning electron microscope S-9220 (manufactured by Hitachi). The results are shown in Table 2 as “Resolution (nm)”.

[DOF evaluation]
For each resist composition, an isolated line pattern is formed by shifting the focus appropriately up and down at Eop where an isolated line pattern with a line of 160 nm (pitch 1600 nm) is obtained, and the line pattern is ± 5% of the target dimension ( That is, the depth of focus (DOF, unit: μm) that can be formed within the range of the dimensional change rate of 152 to 168 nm was determined. It can be said that the larger the value, the wider the range in which a resist pattern faithful to the mask pattern can be obtained, which is preferable.

[Shape evaluation]
The cross-sectional shape of the pattern formed at the optimum exposure amount Eop for forming the 140 nm 1: 1 L / S pattern was observed using a scanning electron microscope (trade name: S-4700, manufactured by Hitachi, Ltd.) The shape was evaluated according to the following criteria. The results are shown in Table 2.
○: The rectangularity is high.
X: It is a head-up shape and rectangularity is low.

[Development defect evaluation]
The 140 nm 1: 1 L / S resist pattern obtained as described above was observed using a surface defect observation apparatus KLA2371 (product name) manufactured by KLA Tencor. Table 2 shows the result of measuring the number of development defects in the unexposed area per silicon wafer.

[Contact angle measurement]
Water is dropped on the surface of a resist film (resist film before exposure) having a thickness of 250 nm obtained in the same manner as described above, and contact angle is measured using DROP MASTER-700 (product name, manufactured by Kyowa Interface Science Co., Ltd.). (Measurement of contact angle: 2 μL of water) The results are shown in Table 2 as “contact angle after application (°)”.
Next, the wafer after measuring the contact angle after application was treated with a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution NMD-3 (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 23 ° C. After performing alkaline development for 30 seconds and then rinsing with pure water for 30 seconds, the contact angle was measured in the same manner as described above, and the results are shown in Table 2 as “Contact angle after development (°)”. .

From the above results, in the positive resist compositions of Examples 1 to 4 according to the present invention, the difference between the contact angle after coating and the contact angle after development is larger than the positive resist compositions of Comparative Examples 1 to 6. It was confirmed that there were few development defects by becoming large and hydrophilic after development.
Moreover, it is clear that Examples 1-4 are excellent in lithographic characteristics, such as resolution and DOF, and pattern shape compared with Comparative Examples 1-6.

Claims (8)

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) is a polymer compound having a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) represented by the following general formula (a1-1) ( A1)
The proportion of the structural unit (a0) is 10 to 60 mol% and the proportion of the structural unit (a1) is 10 to 60 mol% with respect to the total of all the structural units constituting the polymer compound (A1). A positive resist composition characterized in that the total of these is 70 mol% or less.

[Wherein, R represents a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms or a fluorinated alkyl group; R ¹ represents an alkyl group having 1 to 5 carbon atoms, and Y represents X represents an acid dissociable, dissolution inhibiting group; n1 represents an integer of 0 to 5, n2 represents an integer of 0 to 5, 2 ≦ n1 + n2 ≦ 8; It is an integer of ~ 2. ]   The polymer compound (A1) is a structural unit derived from an acrylate ester in which an atom other than a hydrogen atom or a substituent may be bonded to a carbon atom at the α-position, and a lactone-containing cyclic group The positive resist composition according to claim 1, comprising the structural unit (a2).   The polymer compound (A1) is a structural unit derived from an acrylate ester in which an atom other than a hydrogen atom or a substituent may be bonded to a carbon atom at the α-position, and a polar group-containing aliphatic carbonization The positive resist composition according to claim 1, comprising a structural unit (a3) containing a hydrogen group.   Furthermore, the positive resist composition as described in any one of Claims 1-3 containing a nitrogen-containing organic compound component (D).   A step of forming a resist film on the support using the positive resist composition according to any one of claims 1 to 4, a step of exposing the resist film, and an alkali development of the resist film A resist pattern forming method including a step of forming a resist pattern. A polymer compound having a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) represented by the following general formula (a1-1),
The proportion of the structural unit (a0) is 10 to 60 mol% and the proportion of the structural unit (a1) is 10 to 60 mol% with respect to the total of all the structural units constituting the polymer compound. Is a polymer compound characterized in that the total is 70 mol% or less.

[Wherein, R represents a hydrogen atom, an optionally substituted alkyl group having 1 to 4 carbon atoms or a fluorinated alkyl group; R ¹ represents an alkyl group having 1 to 5 carbon atoms, and Y represents X represents an acid dissociable, dissolution inhibiting group; n1 represents an integer of 0 to 5, n2 represents an integer of 0 to 5, 2 ≦ n1 + n2 ≦ 8; It is an integer of ~ 2. ]   Furthermore, it has a structural unit (a2) containing a lactone-containing cyclic group, which is a structural unit derived from an acrylate ester in which an atom other than a hydrogen atom or a substituent may be bonded to the α-position carbon atom. Item 7. The polymer compound according to Item 6.   Furthermore, a structural unit derived from an acrylate ester in which an atom other than a hydrogen atom or a substituent may be bonded to a carbon atom at the α-position, and comprising a polar group-containing aliphatic hydrocarbon group (a3) The high molecular compound of Claim 6 or 7 which has these.