JP6241212B2 - Radiation sensitive resin composition, resist pattern forming method, radiation sensitive acid generator and compound - Google Patents

Description

  The present invention relates to a radiation sensitive resin composition, a resist pattern forming method, a radiation sensitive acid generator and a compound.

  Radiation sensitive resin compositions used for fine processing by lithography are far ultraviolet rays such as KrF excimer laser light (wavelength 248 nm), ArF excimer laser light (wavelength 193 nm) and extreme ultraviolet light (EUV: Extreme Ultraviolet, wavelength 13.5 nm). The acid is generated in the exposed part by irradiation with charged particle beams such as electron beams, and the chemical reaction using this acid as a catalyst causes a difference in the dissolution rate in the developer between the exposed part and the unexposed part. A resist pattern is formed thereon.

  At present, miniaturization of the resist pattern processing technique is being attempted by using a laser beam having a shorter wavelength, an electron beam, an immersion exposure apparatus, or the like. Accordingly, the radiation-sensitive resin composition is required to improve resolution and rectangularity of the cross-sectional shape of the resist pattern. In response to this requirement, the types and molecular structures of the polymer, acid generator, and other components used in the composition have been studied in detail, and further their combinations have been studied in detail (Japanese Patent Laid-Open No. 11-125907). JP-A-8-146610 and JP-A-2000-298347).

  Under such circumstances, recently, it is required to form a resist pattern having a line width of 50 nm or less. The requirements for the resolution and the rectangular shape of the cross-sectional shape are further increased, and a high-accuracy pattern is achieved by being excellent in LWR (Line Width Roughness) performance and CDU (Critical Dimension Uniformity) performance that show variations in the line width of the resist pattern. In addition, it is also required to have excellent MEEF (Mask Error Enhancement Factor) performance, which is an index representing the depth of focus, exposure margin, and mask error tolerance, and to improve process stability. However, the above conventional radiation-sensitive resin composition cannot satisfy these requirements.

Japanese Patent Laid-Open No. 11-125907 JP-A-8-146610 JP 2000-298347 A

  The present invention has been made based on the circumstances as described above, and the purpose thereof is LWR performance, CDU performance, resolution, rectangularity of a cross-sectional shape, depth of focus, exposure margin, and MEEF performance (hereinafter, referred to as the following). Another object of the present invention is to provide a radiation-sensitive resin composition excellent in “LWR performance and the like”.

The invention made to solve the above problems is
A polymer (hereinafter also referred to as “[A] polymer”) having a structural unit containing an acid-dissociable group (hereinafter also referred to as “structural unit (I)”) and a first radiation-sensitive acid generator (hereinafter referred to as “structural unit (I)”). The first radiation-sensitive acid generator is represented by the partial structure represented by the following formula (1-1) and the following formula (1-2). at least one selected from the group consisting of partial structure, SO ₃ ^- is the anion, and a radiation-sensitive resin composition comprising a compound having a radiation-sensitive onium cations containing ^- or COO.

（式（１−１）及び（１−２）中、Ｒ^１は、それぞれ独立して、炭素数３〜３０の置換メタンジイル基である。）

(In formulas (1-1) and (1-2), each R ¹ is independently a substituted methanediyl group having 3 to 30 carbon atoms.)

Another invention made to solve the above problems is as follows:
A resist pattern forming method comprising: forming a resist film; exposing the resist film; and developing the exposed resist film; and forming the resist film from the radiation-sensitive resin composition.

Yet another invention made to solve the above problems is as follows:
An anion comprising at least one selected from the group consisting of the partial structure represented by the above formula (1-1) and the partial structure represented by the above formula (1-2), and SO ₃ ^— or COO ^— ; A radiation-sensitive acid generator comprising a compound having a radiation-sensitive onium cation.

Yet another invention made to solve the above problems is as follows:
It is a compound represented by the following formula (A-1).

（式（Ａ−１）中、Ｒ^１は、炭素数３〜３０の置換メタンジイル基である。Ａ⁻は、ＳＯ_３ ⁻又はＣＯＯ⁻である。Ｒ^２は、単結合又は炭素数１〜２０の２価の有機基である。Ｒ^ｆ１及びＲ^ｆ２は、それぞれ独立して、水素原子、フッ素原子、炭素数１〜２０のアルキル基又は炭素数１〜２０のフッ素化アルキル基である。Ｑ^１〜Ｑ^４は、それぞれ独立して水素原子、ハロゲン原子、ヒドロキシ基若しくは炭素数１〜１０の１価の有機基であるか、又はこれらの基のうちの２つ以上の結合により構成される環員数３〜２０の環構造を表す。Ｘ^＋は、１価の感放射線性オニウムカチオンである。ａは、０〜５の整数である。ａが２以上の場合、複数のＲ^ｆ１及びＲ^ｆ２はそれぞれ同一でも異なっていてもよい。）

(In Formula (A-1), R ¹ is a substituted methanediyl group having 3 to 30 carbon atoms. A ⁻ is SO ₃ ^— or COO ^— . R ² is a single bond or 1 to 20 carbon atoms. R ^f1 and R ^f2 are each independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a fluorinated alkyl group having 1 to 20 carbon atoms. ^{1 to} Q ⁴ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a monovalent organic group having 1 to 10 carbon atoms, or constituted by a bond of two or more of these groups. Represents a ring structure having 3 to 20 ring members, X ⁺ is a monovalent radiation-sensitive onium cation, a is an integer of 0 to 5. When a is 2 or more, a plurality of R ^f1 and R ^f2 may be the same or different.

Yet another invention made to solve the above problems is as follows:
It is a compound represented by a following formula (A-2).

（式（Ａ−２）中、Ｒ^１は、炭素数３〜３０の置換メタンジイル基である。Ａ⁻は、ＳＯ_３ ⁻又はＣＯＯ⁻である。Ｒ^２は、単結合又は炭素数１〜２０の２価の有機基である。Ｒ^ｆ１及びＲ^ｆ２は、それぞれ独立して、水素原子、フッ素原子、炭素数１〜２０のアルキル基又は炭素数１〜２０のフッ素化アルキル基である。Ｑ^５及びＱ^６は、それぞれ独立して水素原子、ハロゲン原子、ヒドロキシ基若しくは炭素数１〜１０の１価の有機基であるか、又はこれらの基が互いに合わせられこれらが結合する炭素原子と共に構成される環員数３〜２０の環構造を表す。Ｘ^＋は、１価の感放射線性オニウムカチオンである。ａは、０〜５の整数である。ａが２以上の場合、複数のＲ^ｆ１及びＲ^ｆ２はそれぞれ同一でも異なっていてもよい。）

(In Formula (A-2), R ¹ is a substituted methanediyl group having 3 to 30 carbon atoms. A ⁻ is SO ₃ ^— or COO ^— . R ² is a single bond or 1 to 20 carbon atoms. R ^f1 and R ^f2 are each independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a fluorinated alkyl group having 1 to 20 carbon atoms. ⁵ and Q ⁶ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a monovalent organic group having 1 to 10 carbon atoms, or these groups are combined with each other to form a carbon atom to which they are bonded. Represents a ring structure having 3 to 20 ring members, X ⁺ is a monovalent radiation-sensitive onium cation, a is an integer of 0 to 5. When a is 2 or more, a plurality of R ^f1 And R ^f2 may be the same or different. )

  Here, the “organic group” refers to a group containing at least one carbon atom.

  According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, while exhibiting excellent depth of focus, exposure margin and MEEF performance, LWR and CDU are small, have high resolution, and have a cross-sectional shape. A resist pattern having excellent rectangularity can be formed. The radiation sensitive acid generator of the present invention can be suitably used as a component of the radiation sensitive resin composition. The compound of the present invention can be suitably used as the radiation sensitive acid generator. Therefore, these can be suitably used for manufacturing processes of semiconductor devices, which are expected to be further miniaturized in the future.

<Radiation sensitive resin composition>
The radiation-sensitive resin composition contains a [A] polymer and a [B] acid generator. Moreover, the said radiation sensitive resin composition is a 2nd radiation sensitive acid generator other than the said 1st radiation sensitive acid generator (henceforth "[C] other acid generators") as a suitable component. , [D] a nitrogen atom-containing compound, [E] a fluorine atom-containing polymer, and [F] a solvent, and may contain other optional components as long as the effects of the present invention are not impaired. Good. Hereinafter, each component will be described.

<[A] polymer>
[A] The polymer is a polymer having the structural unit (I). According to the radiation-sensitive resin composition, the acid-dissociable group of the [A] polymer in the exposed area is dissociated by the acid generated from the [B] acid generator, [C] other acid generator, etc. by radiation irradiation. Thus, there is a difference in solubility in the developer between the exposed portion and the unexposed portion, and as a result, a resist pattern can be formed. The “acid-dissociable group” refers to a group that replaces a hydrogen atom such as a carboxy group or a hydroxy group and dissociates by the action of an acid. [A] The polymer is at least selected from the group consisting of a structural unit represented by the following formula (3-1) and a structural unit represented by (3-2), in addition to the structural unit (I). One type (hereinafter also referred to as “structural unit (II)”), a structural unit represented by the following formula (4) (hereinafter also referred to as “structural unit (III)”), and the structural unit (I) to You may have other structural units other than (III). [A] The polymer may have one or more of each structural unit. Hereinafter, each structural unit will be described.

[Structural unit (I)]
The structural unit (I) is a structural unit containing an acid dissociable group. Examples of the structural unit (I) include a structural unit represented by the following formula (2-1) (hereinafter, also referred to as “structural unit (I-1)”), and a structural unit (2-2). And a structural unit (hereinafter also referred to as “structural unit (I-2)”).

In the formula (2-1), ^{R 3} is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Y ¹ is a monovalent acid dissociable group.
In the above formula (2-2), ^{R 4} is a hydrogen atom or a methyl group. Y ² is a monovalent acid dissociable group.

R ³ is preferably a hydrogen atom or a methyl group, and more preferably a methyl group, from the viewpoint of the copolymerizability of the monomer that gives the structural unit (I-1).

The monovalent acid-dissociable group represented by Y ^1, preferably a group represented by the following formula (Y-1).

In the above formula (Y-1), R ^e1 is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or 6 to 20 carbon atoms. It is a monovalent aromatic hydrocarbon group. R ^e2 and R ^e3 are each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or these groups are An alicyclic structure having 3 to 20 ring members composed of carbon atoms bonded to each other and bonded thereto is represented.

Examples of the monovalent chain hydrocarbon group having 1 to 10 carbon atoms represented by R ^e1 , R ^e2 and R ^e3 include, for example,
Alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl and n-pentyl;
Alkenyl groups such as ethenyl group, propenyl group, butenyl group, pentenyl group;
Examples include alkynyl groups such as ethynyl group, propynyl group, butynyl group, and pentynyl group.
Among these, an alkyl group is preferable, an alkyl group having 1 to 4 carbon atoms is preferable, a methyl group, an ethyl group, and an i-propyl group are more preferable, and an ethyl group is particularly preferable.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ^e1 , R ^e2 and R ^e3 include, for example,
A monocyclic cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group;
A polycyclic cycloalkyl group such as a norbornyl group, an adamantyl group, a tricyclodecyl group, a tetracyclododecyl group;
A monocyclic cycloalkenyl group such as a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, a cyclohexenyl group;
And polycyclic cycloalkenyl groups such as a norbornenyl group and a tricyclodecenyl group.
Among these, a monocyclic cycloalkyl group and a polycyclic cycloalkyl group are preferable, and a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group are more preferable.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by R ^e1 include:
Aryl groups such as phenyl, tolyl, xylyl, mesityl, naphthyl, methylnaphthyl, anthryl, methylanthryl;
Examples include aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group, and anthrylmethyl group.

Examples of the alicyclic structure having 3 to 20 ring members composed of the above-described groups together with the carbon atom to which they are bonded include:
Monocyclic cycloalkane structures such as cyclopropane structure, cyclobutane structure, cyclopentane structure, cyclohexane structure, cyclooctane structure;
Polycyclic cycloalkane structures such as norbornane structure, adamantane structure, tricyclodecane structure and tetracyclododecane structure;
Monocyclic cycloalkene structures such as cyclopropene structure, cyclobutene structure, cyclopentene structure, cyclohexene structure, cyclooctene structure;
Examples thereof include polycyclic cycloalkene structures such as a norbornene structure, a tricyclodecene structure, and a tetracyclododecene structure.
Among these, a monocyclic cycloalkane structure and a polycyclic cycloalkane structure are preferable, a monocyclic cycloalkane structure having 5 to 8 carbon atoms, and a polycyclic cycloalkane structure having 7 to 12 carbon atoms are more preferable, A cyclopentane structure, a cyclohexane structure, a cyclooctane structure, a norbornane structure, and an adamantane structure are more preferable, and a cyclopentane structure and an adamantane structure are particularly preferable.

The group represented by the formula (Y-1) is a carbon in which R ^e1 is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, and R ^e2 and R ^e3 are combined with each other. An alicyclic structure having 3 to 20 ring members constituted with atoms, R ^e1 is a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and R ^e2 and R ^e3 are 1 to C 1 carbon atoms. 10 is preferably a monovalent chain hydrocarbon group, R ^e1 is an alkyl group having 1 to 10 carbon atoms, and R ^e2 and R ^e3 are combined with each other and configured with a carbon atom to which they are bonded. More preferably, it represents a cycloalkane structure having 3 to 20 ring members, R ^e1 is a cycloalkyl group having 3 to 20 carbon atoms, and R ^e2 and R ^e3 are alkyl groups having 1 to 10 carbon atoms, R ^e1 is an alkyl group having 1 to 4 carbon atoms. And represents a monocyclic cycloalkane structure having 5 to 8 ring members or a polycyclic cycloalkane structure having 7 to 12 ring members, which is composed of carbon atoms to which R ^e2 and R ^e3 are combined with each other. More preferred are 1-ethyl-1-cyclopentyl group, 2-ethyl-2-adamantyl group, 2-methyl-2-adamantyl group and 2-adamantyl-2-propyl group.

R ⁴ is preferably a hydrogen atom from the viewpoint of copolymerizability of the monomer that gives the structural unit (I-2).

The monovalent acid-dissociable group represented by Y ^2, preferably a group represented by the following formula (Y-2).

In the above formula (Y-2), R ^e4 , R ^e5 and R ^e6 are each independently a hydrogen atom, a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, or a monovalent group having 3 to 20 carbon atoms. These are alicyclic hydrocarbon groups, oxy-chain hydrocarbon groups having 1 to 20 carbon atoms, or oxyalicyclic hydrocarbon groups having 3 to 20 carbon atoms. However, R ^e4 , R ^e5 and R ^e6 are not simultaneously hydrogen atoms.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms represented by R ^e4 , R ^e5 and R ^e6 include, for example,
Alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl and n-pentyl;
Alkenyl groups such as ethenyl group, propenyl group, butenyl group, pentenyl group;
Examples include alkynyl groups such as ethynyl group, propynyl group, butynyl group, and pentynyl group.
Among these, an alkyl group is preferable, an alkyl group having 1 to 4 carbon atoms is preferable, a methyl group, an ethyl group, and an n-propyl group are more preferable, and a methyl group is particularly preferable.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ^e4 , R ^e5 and R ^e6 include the same groups as those exemplified as R ^e1 , R ^e2 and R ^e3. Etc.
Among these, a monocyclic cycloalkyl group and a polycyclic cycloalkyl group are preferable, and a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group are more preferable.

Examples of the monovalent oxy-chain hydrocarbon group having 1 to 20 carbon atoms represented by R ^e4 , R ^e5 and R ^e6 include, for example,
Alkoxy groups such as methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, i-butoxy group, sec-butoxy group, t-butoxy group and n-pentyloxy group;
Alkenyloxy groups such as ethenyloxy group, propenyloxy group, butenyloxy group, pentenyloxy group;
Examples include alkynyloxy groups such as ethynyloxy group, propynyloxy group, butynyloxy group, and pentynyloxy group.
Among these, an alkoxy group is preferable, an alkoxy group having 1 to 4 carbon atoms is preferable, and a methoxy group, an ethoxy group, and an n-propoxy group are more preferable.

Examples of the monovalent oxyalicyclic hydrocarbon group having 3 to 20 carbon atoms represented by the R ^e4 , R ^e5 and R ^e6 include, for example,
A monocyclic cycloalkyloxy group such as a cyclopropyloxy group, a cyclobutyloxy group, a cyclopentyloxy group, a cyclohexyloxy group, a cyclooctyloxy group;
A polycyclic cycloalkyloxy group such as a norbornyloxy group, an adamantyloxy group, a tricyclodecyloxy group, a tetracyclododecyloxy group;
A monocyclic cycloalkenyloxy group such as a cyclopropenyloxy group, a cyclobutenyloxy group, a cyclopentenyloxy group, a cyclohexenyloxy group;
Examples thereof include polycyclic cycloalkenyloxy groups such as norbornenyloxy group and tricyclodecenyloxy group.
Among these, a monocyclic cycloalkyloxy group and a polycyclic cycloalkyloxy group are preferable, and a cyclopentyloxy group, a cyclohexyloxy group, a norbornyloxy group, and an adamantyloxy group are more preferable.

Examples of the group represented by the formula (Y-2) include a group in which R ^e4 , R ^e5 and R ^e6 are monovalent chain hydrocarbon groups, and R ^e4 and R ^e5 are monovalent chain hydrocarbon groups. And R ^e6 is a monovalent oxy chain hydrocarbon group, R ^e4 is a monovalent chain hydrocarbon group, and R ^e5 and R ^e6 are monovalent oxy chain hydrocarbon groups, A group in which R ^e4 , R ^e5 and R ^e6 are alkyl groups, a group in which R ^e4 and R ^e5 are alkyl groups and R ^e6 is an alkoxy group, a group in which R ^e4 is an alkyl group and R ^e5 and R ^e6 are alkoxy groups ^Are more preferable, R ^e4 , R ^e5 and R ^e6 are more preferably an alkyl group, and a t-butyl group, a t-pentyl group, a t-hexyl group, and a t-heptyl group are particularly preferable.

As the structural unit (I), for example,
As the structural unit (I-1), structural units represented by the following formulas (2-1-1) to (2-1-8);
Examples of the structural unit (I-2) include structural units represented by the following formulas (2-2-1) to (2-2-3).

In the above formulas (2-1-1) to (2-1-8), R ³ has the same meaning as the above formula (2-1). R ^e1 , R ^e2 and R ^e3 have the same ^{meaning as} in the above formula (Y-1). Each r is independently an integer of 1 to 3.
In the above formulas (2-2-1) to (2-2-3), R ⁴ has the same meaning as the above formula (2-2).

  As the structural unit (I), the structural unit (I-1) is preferable, and the above formulas (2-1-2), (2-1-3), (2-1-5) and (2-1-6) are preferable. ) Is more preferred, a group containing a cyclopentane structure and a group containing an adamantane structure are more preferred, and a structural unit derived from 1-ethyl-1-cyclopentyl (meth) acrylate, 2-ethyl-2- A structural unit derived from adamantyl (meth) acrylate, a structural unit derived from 2-methyl-2-adamantyl (meth) acrylate, and a structural unit derived from 2-adamantyl-2-propyl (meth) acrylate are particularly preferred.

  As a content rate of structural unit (I), 10 mol%-90 mol% are preferable with respect to all the structural units which comprise a [A] polymer, 20 mol%-70 mol% are more preferable, 25 mol% -60 mol% is more preferable, and 30 mol%-60 mol% is especially preferable. By making the content rate of structural unit (I) into the said range, the LWR performance of the said radiation sensitive resin composition etc. can be improved more.

[Structural unit (II)]
The structural unit (II) includes a structural unit represented by the following formula (3-1) (hereinafter also referred to as “structural unit (II-1)”) and a structural unit represented by the following formula (3-2) ( Hereinafter, it is at least one selected from the group consisting of “structural unit (II-2)”. When the [A] polymer has the structural unit (II), the [B] acid generator can improve the dispersibility in the [A] polymer. As a result, the radiation sensitive resin composition can further improve the LWR performance and the like. Moreover, the adhesiveness to the board | substrate of the resist pattern formed from the said radiation sensitive resin composition can be improved.

In the formula (3-1), ^{R 5} is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. E ¹ is a single bond, —CO—O—, —CO—NH—, or —CO—O— (CH ₂ ) _i —CO—O—. i is an integer of 1-6. R ⁶ is a non-acid dissociable group containing a polar group.
In said formula (3-2), R < ^{5 '>} is a hydrogen atom or a methyl group. R ^a and R ^b are each independently a hydrogen atom, a fluorine atom, a hydroxy group, or a monovalent organic group. s is an integer of 1 to 3. When s is 2 or more, the plurality of R ^a and R ^b may be the same or different. R ^5a and R ^5b are each independently a hydrogen atom, a fluorine atom, a hydroxy group, or a monovalent organic group.

In the structural unit (II-1),
R ⁵ is preferably a hydrogen atom or a methyl group, and more preferably a methyl group, from the viewpoint of the copolymerizability of the monomer that provides the structural unit (II-1).

E ¹ is preferably —CO—O— from the viewpoint of the copolymerizability of the monomer that gives the structural unit (II-1).

Examples of the polar group in the non-acid dissociable group represented by R ⁶ that includes a polar group include monovalent groups such as a hydroxy group, a carboxy group, a cyano group, a sulfo group, a mercapto group, and an amino group ( a); a carbonyl group, —O—, —S—, —NR′—a divalent group (b) formed by combining these, and the like. R ′ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms.

Examples of the non-acid-dissociable and polar group-containing group represented by R ⁶ include, for example, a part or all of hydrogen atoms of a monovalent hydrocarbon group having 1 to 20 carbon atoms as the monovalent group ( a group substituted with a), a group containing the divalent group (b) between some or all of the carbon-carbons of a monovalent hydrocarbon group having 1 to 20 carbon atoms, monovalent having 1 to 20 carbon atoms A part or all of the hydrogen atoms of the hydrocarbon group is substituted with the monovalent group (a), and a group containing the divalent group (b) between some or all of the carbon-carbons. Can be mentioned.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and carbon. Examples thereof include monovalent aromatic hydrocarbon groups of several 6 to 20.
Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include the same groups as those exemplified as R ^e4 , R ^e5 and R ^e6 in the above formula (Y-2).
Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include the same groups as those exemplified as R ^e1 , R ^e2 and R ^e3 in the above formula (Y-1).
Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include groups similar to those exemplified as R ^e1 in the above formula (Y-1).

Examples of R ⁶ include a group having a lactone structure, a group having a cyclic carbonate structure, a group having a sultone structure, and a group having a hydroxy group.

Examples of the group having the lactone structure include a butyrolactone-yl group, a norbornane lactone-yl group, and a 5-oxo-4-oxatricyclo [4.3.1.1 ^3,8 ] undecan-yl group. It is done.
Examples of the group having a cyclic carbonate structure include an ethylene carbonate-ylmethyl group.
Examples of the group having a sultone structure include groups having a sultone structure such as a propane sultone-yl group and a norbornane sultone-yl group.
Examples of the group having a hydroxy group include a hydroxyadamantyl group, a dihydroxyadamantyl group, a trihydroxyadamantyl group, and a hydroxyethyl group.

In the structural unit (II-2),
R ^{5 ′} is preferably a hydrogen atom from the viewpoint of the copolymerizability of the monomer giving the structural unit (II-2).

Examples of the monovalent organic group represented by R ^a , R ^b , R ^5a and R ^5b include, for example, a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and a monovalent chain having 3 to 20 carbon atoms. An alicyclic hydrocarbon group, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a group in which some or all of the hydrogen atoms of these groups are substituted with a substituent, and the carbon-carbon gap of these groups And —CO—, —CS—, —O—, —S— or —NR ″ — or a group containing a combination of two or more thereof. R ″ represents a hydrogen atom or 1 Valent organic group.

  As s, 1 or 2 is preferable and 1 is more preferable.

As the structural unit (II), for example,
Structural units represented by the following formulas (3-1-1) to (3-1-14) as the structural unit (II-1);
Examples of the structural unit (II-2) include a structural unit represented by the following formula (3-2-1), a structural unit represented by (3-2-2), and the like.

In the above formulas (3-1-1) to (3-1-14), R ⁵ has the same meaning as the above formula (3-1).
In the formulas (3-2-1) and (3-2-2), R ^{5 ′} has the same meaning as the formula (3-2).

  Among these, structural units represented by the above formulas (3-1-1), (3-1-3), (3-1-5) and (3-1-12) are preferable.

  As a content rate of structural unit (II), 0 mol%-90 mol% are preferable with respect to all the structural units which comprise a [A] polymer, 20 mol%-80 mol% are more preferable, 35 mol% More preferred is ˜70 mol%. By making the content rate of structural unit (II) into the said range, the dispersibility in the [A] polymer of [B] acid generator improves more, As a result, the LWR performance of the said radiation sensitive resin composition concerned Etc. can be further improved.

[Structural unit (III)]
The structural unit (III) is a structural unit represented by the following formula (4). When KrF excimer laser light, EUV, electron beam, or the like is used as the radiation to be irradiated, the radiation sensitive resin composition increases the sensitivity because the polymer [A] has the structural unit (III). Can do.

In the formula (4), ^{R 7} is a hydrogen atom or a methyl group. R ⁸ is a monovalent organic group having 1 to 20 carbon atoms. p is an integer of 0-3. If R ⁸ is plural, a plurality of R ⁸ may be the same or different. q is an integer of 1 to 3. However, p + q is 5 or less.

R ⁷ is preferably a hydrogen atom from the viewpoint of the copolymerizability of the monomer giving the structural unit (III).

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ⁸ include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and a monovalent alicyclic group having 3 to 20 carbon atoms. A hydrocarbon group, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a group in which part or all of the hydrogen atoms of these groups are substituted with a substituent, and between these carbon-carbon groups, CO—, —CS—, —O—, —S— or —NR ″ — or a group containing a combination of two or more of these, and the like. R ″ represents a hydrogen atom or a monovalent organic group. It is a group.
Among these, a monovalent chain hydrocarbon group is preferable, an alkyl group is more preferable, and a methyl group is more preferable.

  As said p, the integer of 0-2 is preferable, 0 or 1 is more preferable, and 0 is further more preferable.

  The q is preferably 1 or 2, and more preferably 1.

  Examples of the structural unit (III) include structural units represented by the following formulas (4-1) to (4-4).

In the above formulas (4-1) to (4-4), R ⁷ has the same meaning as the above formula (4).

  Among these, the structural unit represented by the above formula (4-1) and the structural unit represented by (4-2) are preferable, and the structural unit represented by the above formula (4-1) is more preferable.

  As a content rate of structural unit (III), 0 mol%-90 mol% are preferable with respect to all the structural units which comprise a [A] polymer, 30 mol%-80 mol% are more preferable, 50 mol% More preferred is ˜75 mol%. By making the content rate of structural unit (III) into the said range, the said radiation sensitive resin composition can improve a sensitivity more.

  The structural unit (III) is obtained by polymerizing a monomer obtained by substituting the hydrogen atom of the —OH group of hydroxystyrene with an acetyl group, and then subjecting the obtained polymer to a hydrolysis reaction in the presence of an amine. Or the like.

[Other structural units]
[A] The polymer may have other structural units other than the structural units (I) to (III). Examples of the other structural unit include a structural unit derived from a (meth) acrylic acid ester containing a non-dissociable monovalent alicyclic hydrocarbon group. As a content rate of another structural unit, 20 mol% or less is preferable with respect to all the structural units which comprise a [A] polymer, and 10 mol% or less is more preferable.

<[A] Polymer Synthesis Method>
[A] The polymer can be synthesized according to a conventional method such as radical polymerization. For example, (1) a method in which a solution containing a monomer and a radical initiator is dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction, (2) a solution containing the monomer and a radical initiator A method of dropping a solution containing a monomer separately into a reaction solvent or a solution containing a monomer to cause a polymerization reaction, (3) a plurality of types of solutions containing each monomer and a solution containing a radical initiator And a method of polymerizing a solution containing a monomer and a radical initiator in a solvent-free or reaction solvent. Etc. are preferably synthesized.

  In addition, when the monomer solution is dropped and reacted with respect to the monomer solution, the monomer amount in the dropped monomer solution is 30 mol with respect to the total amount of monomers used for polymerization. % Or more, more preferably 50 mol% or more, and even more preferably 70 mol% or more.

  What is necessary is just to determine the reaction temperature in these methods suitably with initiator seed | species. Usually, it is 30 degreeC-150 degreeC, 40 degreeC-150 degreeC is preferable, and 50 degreeC-140 degreeC is more preferable. Although dripping time changes with conditions, such as reaction temperature, the kind of initiator, and the monomer made to react, it is 30 minutes-8 hours normally, 45 minutes-6 hours are preferable, and 1 hour-5 hours are more preferable. Also, the total reaction time including the dropping time varies depending on the conditions as in the dropping time, but is usually 30 minutes to 12 hours, preferably 45 minutes to 12 hours, and more preferably 1 to 10 hours.

  Examples of the radical initiator used in the polymerization include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2,2′-azobis. (2-cyclopropylpropionitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis (2-methylpropionate), dimethyl 2,2'-azobis Examples thereof include azo radical initiators such as isobutyrate; peroxide radical initiators such as benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, and the like. Of these, AIBN and dimethyl 2,2'-azobis (2-methylpropionate) are preferred. In addition, you may use a radical initiator individually or in combination of 2 or more types.

  As a reaction solvent, any solvent other than a solvent that inhibits polymerization (nitrobenzene having a polymerization inhibiting effect, mercapto compound having a chain transfer effect, etc.) and capable of dissolving the monomer may be used. it can. Examples thereof include alcohols, ethers, ketones, amides, esters / lactones, nitriles, and mixed solvents thereof. These solvents may be used alone or in combination of two or more.

  The polymer obtained by the polymerization reaction is preferably recovered by a reprecipitation method. That is, after the polymerization reaction is completed, the polymer is recovered as a powder by introducing the polymerization solution into a reprecipitation solvent. As the reprecipitation solvent, alcohols or alkanes may be used alone or in combination of two or more. In addition to the reprecipitation method, the polymer can be recovered by removing low molecular components such as monomers and oligomers by a liquid separation operation, a column operation, an ultrafiltration operation, or the like.

  [A] The weight average molecular weight (Mw) in terms of polystyrene by GPC (Gel Permeation Chromatography) of the polymer is preferably 1,000 to 50,000, more preferably 2,000 to 40,000, and more preferably 3,000 to 30 Is more preferable, and 5,000 to 20,000 is particularly preferable. [A] If the Mw of the polymer is less than the lower limit, the heat resistance of the resist pattern formed from the radiation-sensitive resin composition may be reduced. [A] If the Mw of the polymer exceeds the above upper limit, the developability of the radiation-sensitive resin composition may be deteriorated.

  [A] The ratio (Mw / Mn, dispersity) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer is preferably 1 to 5, more preferably 1 to 3, and 1 to 2.5. Further preferred.

  [A] The content of the polymer is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 85% by mass or more based on the total solid content in the radiation-sensitive resin composition.

<[B] Acid generator>
[B] The acid generator includes a partial structure represented by the following formula (1-1) (hereinafter also referred to as “partial structure (I-1)”) and a partial structure represented by the following formula (1-2). An anion (hereinafter also referred to as “anion (I)”) containing at least one selected from the group consisting of (hereinafter also referred to as “partial structure (I-2)”) and SO ₃ ^— or COO ^— , and It consists of a compound (hereinafter also referred to as “compound (1)”) having a radiation-sensitive onium cation (hereinafter also referred to as “cation (I)”). The radiation-sensitive resin composition contains [B] acid generator in addition to [A] polymer, so that LWR performance, CDU performance, resolution, rectangularity of cross-sectional shape, depth of focus, exposure Excellent margin and MEEF performance.

In the above formulas (1-1) and (1-2), R ¹ is each independently a substituted methanediyl group having 3 to 30 carbon atoms.

The anion (I) may have only SO ₃ ⁻ or COO ^−, and may have both SO ₃ ⁻ and COO ⁻ . The anion (I) may have one SO ₃ ^— or COO ^— , or two or more, but an anion having one SO ₃ ^— , an anion having one COO ^— preferable. [B] As the form of inclusion of the acid generator, either in the form of a low molecular compound (hereinafter referred to as “[B] acid generator” as appropriate), or in the form of an acid generator group incorporated as part of the polymer, Both of these forms may be used.

[B] Examples of the acid generator include those in which the anion (I) has SO ₃ ^— and two fluorine atoms are bonded to the carbon atom adjacent to the SO ₃ ^— (hereinafter referred to as [B] The acid generator is also referred to as “[B1] acid generator”), the anion (I) has SO ₃ ^— , and the carbon atom adjacent to the SO ₃ ^— is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or carbon. Those having a fluorinated alkyl group of 1 to 20 or those having an anion (I) having COO ⁻ (hereinafter, these [B] acid generators are also referred to as “[B2] acid generators”) Etc.

According to the [B1] acid generator, an acid is generated from the [B1] acid generator upon irradiation with radiation, and the acid dissociable group of the [A] polymer can be dissociated. As a result, [A] The solubility of the polymer in the developer changes, and a resist pattern can be formed. The [B2] acid generator has a relatively high temperature of PEB (Post Exposure Bake) when the resist pattern is formed, and the [A] polymer has the structural unit (I-1) as an acid dissociable group. When the temperature is low (for example, 110 ° C. or lower), a high acid scavenging function due to the basicity of SO ₃ ^— or COO ^— is exhibited in the unexposed area, but the generated protons bind to SO ₃ ^{− in the} exposed area. Becomes SO ₃ H and COO ⁻ becomes COOH, and its acid trapping function is lowered, so that it functions as a highly accurate acid diffusion controller. Furthermore, the [B2] acid generator is used when the [A] polymer has the structural unit (I-1) as an acid dissociable group and the PEB temperature is relatively high (for example, 120 ° C. or more), or [ A] When the polymer has a structural unit (I-2) as an acid dissociable group, the acid generated by irradiation of radiation from this [B2] acid generator serves as a catalyst to [A] acid dissociability of the polymer. It is believed that the group can be dissociated.

The reason why the radiation-sensitive resin composition exhibits the above effect by containing the [B] acid generator is not necessarily clear, but can be inferred as follows, for example. That is, the [B] acid generator has a norbornane structure, and R ^{1 at the} bridge head position is a substituted methanediyl group having 3 to 30 carbon atoms. As a result, the [B] acid generator has an appropriate bulkiness, and as a result, the diffusion of the acid generated from the [B1] acid generator and the acid generated from the [B2] acid generator is appropriately shortened. Therefore, according to the [B] acid generator, the LWR performance etc. of the said radiation sensitive resin composition can be improved. [B] The acid generators may be used singly or in combination of two or more.

[Anion (I)]
The anion (I) includes at least one selected from the group consisting of the partial structure (I-1) and the partial structure (I-2), and SO ₃ ^— or COO ^— .

Examples of the substituted methanediyl group represented by R ¹ include a substituted methanediyl group (c) having two monovalent substituents (hereinafter also referred to as “group (c)”), a substituted ethenylidene group (d). (Hereinafter also referred to as “group (d)”) and a substituted methanediyl group (e) having one divalent substituent (hereinafter also referred to as “group (e)”). Examples of the substituent of the group (d) include those having two monovalent substituents, those having one divalent substituent, and the like.

  As a monovalent substituent which the said group (c) and group (d) have, a monovalent organic group etc. are mentioned, for example.

Examples of the monovalent organic group include:
A monovalent hydrocarbon group having 1 to 20 carbon atoms, a group (g) containing a divalent heteroatom-containing group at a carbon-carbon end or a bond-side end of the hydrocarbon group, the hydrocarbon group and the group ( and a group in which part or all of the hydrogen atoms in g) are substituted with a monovalent heteroatom-containing group.

  Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a chain hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, and an aromatic having 6 to 20 carbon atoms. Group hydrocarbon group and the like.

Examples of the chain hydrocarbon group include:
Alkyl groups such as methyl, ethyl, propyl, butyl, and pentyl groups;
Alkenyl groups such as ethenyl group, propenyl group, butenyl group, pentenyl group;
Examples thereof include alkynyl groups such as ethynyl group, propynyl group, butynyl group, and pentynyl group.

Examples of the alicyclic hydrocarbon group include:
Monocyclic cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group;
A polycyclic cycloalkyl group such as a norbornyl group, an adamantyl group, a tricyclodecyl group, a tetracyclododecyl group;
A monocyclic cycloalkenyl group such as a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, a cyclohexenyl group;
Examples thereof include polycyclic cycloalkenyl groups such as norbornenyl group and tricyclodecenyl group.

Examples of the aromatic hydrocarbon group include:
Aryl groups such as phenyl, tolyl, xylyl, naphthyl and anthryl;
Examples thereof include aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group and anthrylmethyl group.

  Examples of the hetero atom contained in the monovalent and divalent heteroatom-containing group include an oxygen atom, a sulfur atom, a nitrogen atom, a silicon atom, and a phosphorus atom. In these, an oxygen atom, a sulfur atom, and a nitrogen atom are preferable, and an oxygen atom is more preferable.

  Examples of the divalent heteroatom-containing group include —O—, —CO—, —CS—, —NR′—, and a combination thereof. R ′ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms.

  Examples of the monovalent heteroatom-containing group include a hydroxy group, a carboxy group, a sulfanyl group (—SH), an amino group, and a cyano group.

  Of these, the monovalent substituent of the group (c) and the group (d) is preferably an alicyclic hydrocarbon group or an aromatic hydrocarbon group, and a monocyclic cycloalkyl group or a polycyclic cyclohexane. An alkyl group and an aryl group are preferable, and a cyclohexyl group, an adamantyl group, and a phenyl group are more preferable.

  As a bivalent substituent which the said group (d) and group (e) have, a bivalent organic group etc. are mentioned, for example. Examples of the divalent organic group include groups obtained by removing one hydrogen atom from the monovalent organic groups exemplified above.

  Among these, a monocyclic cycloalkane-1,1-diyl group, a polycyclic cycloalkane-2,2-diyl group, and a hydroxy-substituted polycyclic cycloalkane-2,2-diyl group are preferable, Cyclohexane-1,1-diyl group, norbornane-2,2-diyl group, adamantane-2,2-diyl group, 5-hydroxyadamantane-2,2-diyl group, decalin-2,2-diyl group and more preferable.

The lower limit of the carbon number of the substituted methanediyl group represented by R ¹ is 3, 4 is preferable, 6 is more preferable, 7 is more preferable, 8 is particularly preferable, and 10 is more particularly preferable. On the other hand, as an upper limit of this carbon number, it is 30, 25 is preferable, 20 is more preferable, 17 is further more preferable, and 15 is especially preferable. When the number of carbon atoms is in the above range, the [B] acid generator has an appropriate bulkiness, and as a result, the diffusion of the acid generated from the [B] acid generator is appropriately shortened.

[Cation (I)]
The cation (I) is a radiation-sensitive onium cation. The radiation-sensitive onium cation is a cation that is decomposed by the action of radiation. In the exposed portion, a carboxylic acid is generated from the proton generated by the decomposition of the cation (I) and the sulfonate anion of the compound (1) from the sulfonic acid or the carbonate anion. For example, as the cation (I), for example, S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, Bi, etc. The radiation-sensitive onium cation. Of these, monovalent radiation-sensitive onium cations are preferred. Examples of the cation containing S (sulfur) as an element include a sulfonium cation and a tetrahydrothiophenium cation. Examples of the cation containing I (iodine) as an element include an iodonium cation. Among these, a sulfonium cation represented by the following formula (X-1) and an iodonium cation represented by the following formula (X-2) are preferable.

In the above formula (X-1), R ⁹ , R ¹⁰ and R ¹¹ are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, substituted or unsubstituted carbon. number 6-12 aromatic hydrocarbon group, -OSO ₂ -R ^a or _-SO 2 -R ^B or where represents the ring structure formed by two or more binding of these groups. R ^A and R ^B are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k, m, and n are each independently an integer of 0 to 5. R ⁹ to R ^11, when ^{R A} and ^{R B} is plural respective plurality of ^R 9 ^{to R} 11, ^{R A} and ^{R B} may be respectively the same or different.
In the formula (X-2), R ¹² and R ¹³ are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon group having 6 to 6 carbon atoms. 12 aromatic hydrocarbon group, represents a cyclic structure formed by two or more binding of either a -OSO ₂ -R ^C or _-SO 2 -R ^D, or their groups. R ^C and R ^D are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. i and j are each independently an integer of 0 to 5. R ^{12, R} 13, ^R when ^C and more ^{R D} are each the plurality of ^{R 12,} R 13, ^{R C} and ^{R D} may be respectively the same or different.

Examples of the unsubstituted linear alkyl group represented by R ^{9 to} R ¹³ include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group.
Examples of the unsubstituted branched alkyl group represented by R ^{9 to} R ¹³ include an i-propyl group, an i-butyl group, a sec-butyl group, and a t-butyl group.
The unsubstituted aromatic hydrocarbon group represented by R ⁹ to R ^13, for example, aryl groups such as phenyl and naphthyl; benzyl, and aralkyl groups such as phenethyl group.

Examples of the substituent that may substitute the hydrogen atom of the alkyl group and aromatic hydrocarbon group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, a hydroxy group, a carboxy group, and a cyano group. Group, nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, acyloxy group and the like.
Among these, a halogen atom is preferable and a fluorine atom is more preferable.

Examples of R ^{9 to} R ¹³ include an unsubstituted linear or branched alkyl group, a fluorinated alkyl group, an unsubstituted monovalent aromatic hydrocarbon group, —OSO ₂ —R ″, —SO ₂ —. R ″ is preferred, a fluorinated alkyl group and an unsubstituted monovalent aromatic hydrocarbon group are more preferred, and a fluorinated alkyl group is more preferred. R ″ is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

As k, m, and n in the formula (X-1), integers of 0 to 2 are preferable, 0 or 1 is more preferable, and 0 is more preferable.
As i and j in the said Formula (X-2), the integer of 0-2 is preferable, 0 or 1 is more preferable, and 0 is further more preferable.

[Compound (A-1) and Compound (A-2)]
Examples of the compound (1) include a compound represented by the following formula (A-1) (hereinafter also referred to as “compound (A-1)”) and a compound represented by the following formula (A-2) (hereinafter referred to as “compound (A-1)”). , “Compound (A-2)”) and the like.

In the formulas (A-1) and (A-2), R ¹ has the same meaning as the formulas (1-1) and (1-2). A ^- it is, SO ₃ ^- or COO ^- is. R ² is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ^f1 and R ^f2 are each independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a fluorinated alkyl group having 1 to 20 carbon atoms. Q ^{1 to} Q ⁴ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a monovalent organic group having 1 to 10 carbon atoms, or constituted by a bond of two or more of these groups. Represents a ring structure having 3 to 20 ring members. Q ⁵ and Q ⁶ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a monovalent organic group having 1 to 10 carbon atoms, or together with the carbon atom to which these groups are combined with each other and bonded to each other. It represents a ring structure having 3 to 20 ring members. X ⁺ is a monovalent radiation-sensitive onium cation. a is an integer of 0-5. When a is 2 or more, the plurality of R ^f1 and R ^f2 may be the same or different.

Examples of the monovalent organic group represented by Q ^{1 to} Q ⁶ include the same groups as the monovalent organic group exemplified as the substituent of the group (c) and the group (d) in R ¹ . Is mentioned.

Among these, Q ^{1 to} Q ⁶ are preferably a hydrogen atom, a hydroxy group, a group containing —COO— or an alicyclic hydrocarbon group, and a group containing a hydrogen atom, a hydroxy group or —COO—, A cyclic cycloalkyl group and a polycyclic cycloalkyl group are more preferable, a hydrogen atom, a hydroxy group, and a cycloalkyloxycarbonyl group are more preferable, and a hydrogen atom, a hydroxy group, and a cyclohexyloxycarbonyl group are particularly preferable.

Examples of the ring structure constituted by two or more bonds among the groups represented by Q ^{1 to} Q ⁶ include, for example,
Monocyclic cycloalkane structures such as cyclopropane structure, cyclobutane structure, cyclopentane structure, cyclohexane structure, cyclooctane structure;
Polycyclic cycloalkane structures such as norbornane structure, adamantane structure, tricyclodecane structure and tetracyclododecane structure;
Monocyclic cycloalkene structures such as cyclopropene structure, cyclobutene structure, cyclopentene structure, cyclohexene structure, cyclooctene structure;
Polycyclic cycloalkene structures such as norbornene structure, tricyclodecene structure, tetracyclododecene structure;
A ring structure having one oxygen atom, such as an oxacyclopentane structure or an oxacyclocyclohexane structure;
A ring structure having two oxygen atoms, such as a dioxacyclopentane structure and a dioxacyclocyclohexane structure;
Lactone structures such as butyrolactone structure and norbornane lactone structure;
Examples thereof include imide structures such as an adipic imide structure, a succinic imide structure, and a glutaric imide structure.

  Among these, a monocyclic cycloalkane structure, a polycyclic cycloalkane structure, a ring structure having two oxygen atoms, a ring structure having a carbonyl group, and an imide structure are preferable. A cycloalkane structure, a polycyclic cycloalkane structure having 7 to 12 carbon atoms, a ring structure having two oxygen atoms, a lactone structure, and an imide structure are more preferable, and a 1,3-dioxacyclopentane structure and a succinimide structure Is more preferable.

Examples of the divalent organic group having 1 to 20 carbon atoms represented by R ^2, include groups derived by removing one hydrogen atom from a monovalent organic group exemplified as the Q ¹ to Q ⁶ .

R ² is preferably a single bond or a divalent chain hydrocarbon group, preferably a single bond or an alkanediyl group, more preferably a single bond or a linear alkanediyl group, a single bond, a methanediyl group, 1,2-ethanediyl group and 1,3-propanediyl group are more preferable, and a single bond and methanediyl group are particularly preferable.

Examples of the alkyl group having 1 to 20 carbon atoms represented by R ^f1 and R ^f2 include, for example,
A methyl group, an ethyl group, a propyl group, a butyl group, etc. are mentioned.
Examples of the fluorinated alkyl group having 1 to 20 carbon atoms represented by R ^f1 and R ^f2 include a trifluoromethyl group and a trifluoroethyl group.

As said ^Rf1 and ^Rf2 , a hydrogen atom, a fluorine atom, a methyl group, and a trifluoromethyl group are preferable, and a hydrogen atom and a fluorine atom are more preferable.

  As said a, the integer of 0-5 is preferable, 0-2 are more preferable, and 0 or 2 is further more preferable.

As the compound (A-1) or (A-2), compounds represented by the following formulas (1-a) to (1-d) (hereinafter referred to as “compounds (1-a) to (1-d)”) Also called). Compound (1-a) and compound (1-c) are cases where the substituted methanediyl group represented by R ¹ is the group (d). In the compound (1-b) and the compound (1-d), the substituted methanediyl group represented by R ¹ is a group (c) or a group (e).

In the above formulas (1-a) to (1-d), R ^{X1 to} R ^X4 are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a monovalent organic group having 1 to 20 carbon atoms, or These groups represent a ring structure having 2 to 28 ring members constituted together with the carbon atom to which they are bonded. ^{Q 1 ~Q 6, R 2,} R f1, R f2, A -, X + , and a are as defined in the above formula (A-1) or (A-2).

  Of these, the compounds (1-a), (1-b), and (1-c) are preferable.

  Examples of the compound (1) include compounds represented by the following formulas (1-1-1) to (1-1-24) (hereinafter referred to as “compounds (1-1-1) to (1-1-24)”. Or the like).

  Of these, compounds (1-1-1) to (1-1-12) are preferred.

In the case of a compound represented by the following formula (1 ′) in which A ⁻ in the above formula (A-1) is SO ₃ ^— , the compound (1) is represented by the following reaction scheme,
(A) Diels-Alder addition represented by the following formula (ic) by reacting a fulvene compound represented by the following formula (ia) with a halogen compound represented by the following formula (ib) Obtaining a body,
(B) reacting the Diels-Alder adduct (ic) with Q ² -Q ⁴ to obtain a compound represented by the following formula (id);
(C) a step of reacting the compound (id) with an alkali metal dithionite represented by E ₂ S ₂ O ₄ to obtain a compound represented by the following formula (ie);
(D) a step of reacting the compound (ie) with hydrogen peroxide to obtain a sulfonate represented by the following formula (if); and (E) the sulfonate (if). And an onium salt represented by X ⁺ M ⁻ can be synthesized by a method for synthesizing a compound.

In the above scheme, R ¹ is a substituted methanediyl group having 3 to 30 carbon atoms. R ² is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ^f1 and R ^f2 are each independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a fluorinated alkyl group having 1 to 20 carbon atoms. Q ^{1 to} Q ⁴ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a monovalent organic group having 1 to 10 carbon atoms, or constituted by a bond of two or more of these groups. Represents a ring structure having 3 to 20 ring members. X ⁺ is a monovalent radiation-sensitive onium cation. a is an integer of 0-5. When a is 2 or more, the plurality of R ^f1 and R ^f2 may be the same or different. Z is a halogen atom. E ⁺ is an alkali metal ion. M ⁻ is a monovalent anion.

In the step (A), the Diels-Alder adduct (ic) is reacted with the fulvene compound (ia) and the halogen compound (ib) in a solvent such as toluene. Is obtained.
In the step (B), the compound (id) is obtained by reacting the Diels-Alder adduct (ic) with the compound represented by Q ² -Q ⁴ . In this reaction, for example, hydrogen molecules and the like can be mentioned as Q ² -Q ⁴ , and can be reacted in an organic solvent or the like using a Pd catalyst or the like.
In the step (C), the compound (id) and an alkali metal dithionite represented by E ₂ S ₂ O ₄ are reacted in an organic solvent in the presence of a base such as sodium hydrogen carbonate, for example. Thus, the compound (ie) is obtained.
In the step (D), the compound (ie) and hydrogen peroxide are reacted to obtain the sulfonate (if).
Subsequently, in the step (E), the sulfonic acid salt (if) and the onium salt represented by X ⁺ M ⁻ are reacted in a solvent such as dichloromethane / water, for example, to thereby react the compound ( 1 ′) is obtained. The produced compound (1 ′) can be isolated by purification by solvent washing, recrystallization and the like. The compound (1) other than the compound (1 ′) can also be synthesized by the same method as described above.

[B] When the [B] acid generator is a [B] acid generator, the content of the [B] acid generator is 0.2 to 30 parts by mass with respect to 100 parts by mass of the [A] polymer. Preferably, 0.5 mass part-20 mass parts are more preferable, 1 mass part-15 mass parts are further more preferable, and 2 mass parts-10 mass parts are especially preferable.
[B] By making content of an acid generator into the said range, the LWR performance of the said radiation sensitive resin composition etc. can be improved more.

<[C] Other acid generators>
[C] The other acid generator is a radiation sensitive acid generator other than the [B] acid generator. [C] Other acid generators include, for example, a radiation-sensitive onium cation and an anion having SO ₃ ⁻ and having two fluorine atoms bonded to the carbon atom adjacent to the SO ₃ ^−. compound (hereinafter, also referred to as "[C1] other acid generator"), a radiation-sensitive onium cation, SO ₃ ^- this SO ₃ has a ^- hydrogen atom to a carbon atom adjacent to, 1 to 20 carbon atoms A compound composed of an anion to which an alkyl group or a fluorinated alkyl group having 1 to 20 carbon atoms is bonded, or a compound composed of a radiation-sensitive onium cation and an anion having COO ⁻ (hereinafter referred to as “[C2] Radiation sensitive acid generators other than [C1] other acid generators and [C2] other acid generators (hereinafter also referred to as “[C3] other acid generators”). ) And the like. [C1] According to another acid generator, the acid generated by exposure dissociates the acid dissociable group of the [A] polymer, and as a result, the solubility of the [A] polymer in the developer changes. A resist pattern can be formed. Also, [C2] other acid generator, in the unexposed area SO ₃ ^- or COO ^- is high acid trapping function by basic with is exhibited by protons generated in the exposed portion, the SO ₃ ^- Becomes SO ₃ H and COO ⁻ becomes COOH, and its acid scavenging function is lowered, so that it functions as an acid diffusion control agent. [C] As a form of inclusion of the other acid generator, a low molecular compound form (hereinafter referred to as “[C] other acid generator” as appropriate) is incorporated as part of the polymer. Either of these embodiments may be used. [C] Other acid generators may be used singly or in combination of two or more.

[C1] Other acid generators and [C2] other acid generators include, for example, onium salt compounds such as sulfonium salts, tetrahydrothiophenium salts, and iodonium salts. [C1] Other acid generators and [C2] other acid generators preferably have a monovalent radiation-sensitive onium cation and a monovalent anion.
[C3] Examples of other acid generators include N-sulfonyloxyimide compounds, oxime sulfonate compounds, halogen-containing compounds, and diazoketone compounds.

[C1] Examples of other acid generators include:
Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, cyclohexyl 2-oxocyclohexylmethylsulfonium trifluoromethanesulfonate, dicyclohexyl 2-oxocyclohexyl. Sulfonium trifluoromethanesulfonate, 2-oxocyclohexyldimethylsulfonium trifluoromethanesulfonate, 4-hydroxy-1-naphthyldimethylsulfonium trifluoromethanesulfonate, triphenylsulfonium 2- (adamantan-1-yl) -1,1-difluoroethane-1-sulfonate , Triphenylsulfonium 4- ( Damantan-1-ylcarbonyloxy) -1,1,2,2-tetrafluorobutane-1-sulfonate, triphenylsulfonium 2- (adamantan-1-ylcarbonyloxy) -1,1,3,3,3- Pentafluoropropane-1-sulfonate, etc.
Examples of the tetrahydrothiophenium salt include 4-hydroxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-hydroxy-1-naphthyltetrahydrothiophenium nonafluoro-n-butanesulfonate, 4-hydroxy-1-naphthyltetrahydro Thiophenium perfluoro-n-octanesulfonate, 1- (1-naphthylacetomethyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (1-naphthylacetomethyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1 -(1-naphthylacetomethyl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophene Mutrifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium per Such as fluoro-n-octane sulfonate,
Examples of the iodonium salt include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t -Butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, and the like.

  [C1] As other acid generators, among these, onium salt compounds are preferable, sulfonium salts are more preferable, triphenylsulfonium salts are more preferable, and triphenylsulfonium 2- (adamantan-1-ylcarbonyloxy). -1,1,3,3,3-pentafluoropropane-1-sulfonate is particularly preferred.

[C2] Other acid generators include, for example,
Examples of the sulfonium salt include triphenylsulfonium salicylate, triphenylsulfonium 10-camphorsulfonium salt, and the like.
Examples of the tetrahydrothiophenium salt include 4-hydroxy-1-naphthyltetrahydrothiophenium salicylate, 4-hydroxy-1-naphthyltetrahydrothiophenium 10-camphorsulfonate, 1- (1-naphthylacetomethyl) tetrahydrothio Phenium salicylate, 1- (1-naphthylacetomethyl) tetrahydrothiophenium 10-camphorsulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium salicylate, 1- (3 , 5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 10-camphorsulfonate, etc.
Examples of the iodonium salt include diphenyliodonium salicylate, diphenyliodonium 10-camphor sulfonate, bis (4-t-butylphenyl) iodonium salicylate, bis (4-t-butylphenyl) iodonium 10-camphorsulfonate, and the like. .
[C2] The other acid generator is preferably an onium salt compound, more preferably a sulfonium salt, still more preferably a triphenylsulfonium salt, and particularly preferably triphenylsulfonium salicylate.

[C3] Other acid generators include, for example,
As N-sulfonyloxyimide compounds, N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoro-n-butanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide and the like.

  [C] As the content of the other acid generator, [C] When the other acid generator is [C] another acid generator, from the viewpoint of sensitivity and developability of the radiation-sensitive resin composition, [A] 0 mass part-30 mass parts are preferable with respect to 100 mass parts of polymers, 0.5 mass part-20 mass parts are more preferable, 2 mass parts-10 mass parts are more preferable.

  Moreover, when the said radiation sensitive resin composition contains a [B1] acid generator as said [B] acid generator, as a content of [C1] other acid generators, it is [B1] acid generator 100. 0 mass part-90 mass parts are preferable with respect to a mass part, 10 mass parts-80 mass parts are more preferable, and 20 mass parts-75 mass parts are more preferable. When the radiation sensitive resin composition contains [B1] acid generator, the content of [C1] other acid generator is within the above range, so that the LWR performance of the radiation sensitive resin composition can be improved. The sensitivity can be further increased while maintaining.

  Moreover, when the said radiation sensitive resin composition contains a [B2] acid generator as said [B] acid generator, as content of [C2] other acid generators, it is [B2] acid generator 100. 0 mass parts-100 mass parts are preferable with respect to a mass part, and 10 mass parts-95 mass parts are more preferable. When the radiation sensitive resin composition contains [B2] acid generator, the content of [C2] other acid generator is set in the above range, so that the LWR performance of the radiation sensitive resin composition can be improved. The sensitivity can be further increased while maintaining.

<[D] Nitrogen atom-containing compound>
[D] The nitrogen atom-containing compound is a compound containing a nitrogen atom. [D] The nitrogen atom-containing compound can moderately shorten the diffusion of the acid generated from the [B] acid generator and [C] other acid generators. The said radiation sensitive resin composition can further improve LWR performance etc. by further containing a [D] nitrogen atom containing compound. [D] You may use a nitrogen atom containing compound individually by 1 type or in combination of 2 or more types.

  [D] Examples of the nitrogen atom-containing compound include amine compounds, amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

  Examples of the amine compound include mono (cyclo) alkylamines; di (cyclo) alkylamines; tri (cyclo) alkylamines; substituted alkylanilines or derivatives thereof; ethylenediamine, N, N, N ′, N ′. -Tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylamine, 2,2-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4 -Aminophenyl) -2- (4-hydroxyphenyl) propane 1,4-bis (1- (4-aminophenyl) -1-methylethyl) benzene, 1,3-bis (1- (4-aminophenyl) -1-methylethyl) benzene, bis (2-dimethylamino) Ethyl) ether, bis (2-diethylaminoethyl) ether, 1- (2-hydroxyethyl) -2-imidazolidinone, 2-quinoxalinol, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ) Ethylenediamine, N, N, N ′, N ″ N ″ -pentamethyldiethylenetriamine and the like.

  Examples of the amide group-containing compound include Nt-butoxycarbonyl group-containing amino compounds such as Nt-butoxycarbonyl-4-hydroxypiperidine; N-t such as Nt-amyloxycarbonyl-4-hydroxypiperidine. t-amyloxycarbonyl group-containing amino compound; formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone, N-acetyl-1-adamantylamine, isocyanuric acid tris (2-hydroxyethyl) and the like can be mentioned.

  Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, and tri-n-butyl. Examples include thiourea.

  Examples of the nitrogen-containing heterocyclic compound include imidazoles such as 2-phenylimidazole; pyridines; piperazines; pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, piperidineethanol, 3-piperidino-1,2 -Propanediol, morpholine, 4-methylmorpholine, 1- (4-morpholinyl) ethanol, 4-acetylmorpholine, 3- (N-morpholino) -1,2-propanediol, 1,4-dimethylpiperazine, 1,4 -Diazabicyclo [2.2.2] octane, N- (undecan-1-ylcarbonyloxyethyl) morpholine and the like.

  Among these, a nitrogen-containing heterocyclic compound is preferable, and N- (undecan-1-ylcarbonyloxyethyl) morpholine is more preferable.

  [D] The content of the nitrogen atom-containing compound is preferably 30 parts by mass or less, more preferably 0.1 parts by mass to 20 parts by mass, and 0.5 parts by mass with respect to 100 parts by mass of the polymer [A]. More preferably, it is 10 mass parts. [D] By making content of a nitrogen atom containing compound into the said range, the LWR performance of the said radiation sensitive resin composition etc. can be improved further.

<[E] Fluorine atom-containing polymer>
[E] A fluorine atom containing polymer is a polymer containing a fluorine atom. According to the radiation sensitive resin composition, in addition to the [A] polymer, the [E] fluorine atom-containing polymer is formed on the surface layer of the resist film by further containing the [E] fluorine atom-containing polymer. As a result, the hydrophobicity of the resist film surface can be improved. As a result, when performing immersion exposure, etc., the substance elution suppression from the resist film is excellent, and the receding contact angle between the resist film and the immersion liquid can be sufficiently increased, enabling faster scanning. Become.

  [E] The fluorine atom-containing polymer is not particularly limited, but (1) the polymer itself is insoluble in the developer and becomes alkali-soluble by the action of acid, and (2) itself is soluble in the developer. A polymer whose alkali solubility is increased by the action of an acid; (3) a polymer which is itself insoluble in a developer and becomes alkali-soluble by the action of an alkali; and (4) itself is soluble in a developer. And polymers whose alkali solubility is increased by the action of alkali.

[E] As an aspect of a fluorine atom containing polymer, for example,
A structure in which a fluorinated alkyl group is bonded to the main chain;
A structure in which a fluorinated alkyl group is bonded to the side chain;
Examples include a structure in which a fluorinated alkyl group is bonded to the main chain and the side chain.

  Examples of the monomer that gives a structure in which a fluorinated alkyl group is bonded to the main chain include, for example, α-trifluoromethyl acrylate compound, β-trifluoromethyl acrylate compound, α, β-trifluoromethyl acrylate compound, one or more types And compounds in which the hydrogen atom of the vinyl moiety is substituted with a fluorinated alkyl group such as a trifluoromethyl group.

  Examples of monomers that give a structure in which a fluorinated alkyl group is bonded to the side chain include, for example, those in which the side chain of an alicyclic olefin compound such as norbornene is a fluorinated alkyl group or a derivative thereof, acrylic acid or methacrylic acid. Examples include ester compounds in which the side chain is a fluorinated alkyl group or a derivative thereof, and one or more olefin side chains (sites not including a double bond) being a fluorinated alkyl group or a derivative thereof.

  Monomers that give a structure in which a fluorinated alkyl group is bonded to the main chain and side chain include, for example, α-trifluoromethylacrylic acid, β-trifluoromethylacrylic acid, α, β-trifluoromethylacrylic acid. Such as a fluorinated alkyl group or its derivative ester compound, or a compound in which the hydrogen atom of one or more vinyl moieties is substituted with a fluorinated alkyl group such as a trifluoromethyl group, Substituted by the derivative, a hydrogen atom bonded to a double bond of one or more alicyclic olefin compounds is substituted with a fluorinated alkyl group such as a trifluoromethyl group, and the side chain is a fluorinated alkyl group And those which are derivatives thereof. In addition, an alicyclic olefin compound shows the compound in which a part of ring is a double bond.

  [E] As the fluorine atom-containing polymer, a structural unit represented by the following formula (6) (hereinafter also referred to as “structural unit (f1)”) and / or a structural unit represented by the following formula (7) ( Hereinafter, it is also preferable to have “structural unit (f2)”. [E] The fluorine atom-containing polymer may have other structural units other than the structural unit (f1) and the structural unit (f2). In addition, the [E] fluorine atom containing polymer may contain 1 type, or 2 or more types of each structural unit. Hereinafter, each structural unit will be described in detail.

[Structural unit (f1)]
The structural unit (f1) is a structural unit represented by the following formula (6).

In the above formula (6), R ^f3 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^f4 is a substituted or unsubstituted monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms or a substituted or unsubstituted monovalent fluorinated alicyclic hydrocarbon group having 4 to 20 carbon atoms. .

  Examples of the monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms include a fluoromethyl group, a trifluoromethyl group, a trifluoroethyl group, a pentafluoro-n-propyl group, and a hexafluoro-i-propyl group. Group, nonafluoro-n-butyl group and the like.

  Examples of the monovalent fluorinated alicyclic hydrocarbon group having 4 to 20 carbon atoms include a fluorocyclopentyl group, a difluorocyclopentyl group, a cyclopentyldifluoropropyl group, a perfluorocyclohexyl group, a cyclohexyldifluoromethyl group, and a perfluorocycloheptyl group. Groups and the like.

  Examples of the monomer that gives the structural unit (f1) include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, and perfluoro n-propyl. (Meth) acrylate, perfluoro i-propyl (meth) acrylate, perfluoro n-butyl (meth) acrylate, perfluoro i-butyl (meth) acrylate, perfluoro t-butyl (meth) acrylate, perfluorocyclohexyl (meta ) Acrylate, 2- (1,1,1,3,3,3-hexafluoro) propyl (meth) acrylate, 1- (2,2,3,3,4,4,5,5-octafluoro) pentyl (Meth) acrylate, 1- (2,2,3,3,4,4,5,5-octafluoro) he Sil (meth) acrylate, perfluorocyclohexylmethyl (meth) acrylate, 1- (2,2,3,3,3-pentafluoro) propyl (meth) acrylate, 1- (2,2,3,3,4,4) 4,4-Heptafluoro) penta (meth) acrylate, 1- (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- Heptadecafluoro) decyl (meth) acrylate, 1- (5-trifluoromethyl-3,3,4,4,5,6,6,6-octafluoro) hexyl (meth) acrylate and the like.

  As the structural unit (f1), a structural unit represented by the following formula (6-1) and a structural unit represented by (6-2) are preferable.

In the formulas (6-1) and (6-2), R ^f3 has the same ^meaning as the formula (6).

  Among these, the structural unit represented by Formula (6-1) is preferable.

  As a content rate of a structural unit (f1), 10 mol%-70 mol% are preferable with respect to all the structural units which comprise a [E] fluorine atom containing polymer, and 20 mol%-50 mol% are more preferable.

[Structural unit (f2)]
The structural unit (f2) is a structural unit represented by the following formula (7).

In the above formula (7), R ^f5 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^f6 is a (r + 1) -valent linking group. X ¹ is a divalent linking group having a fluorine atom. R ^f7 is a hydrogen atom or a monovalent organic group. r is an integer of 1 to 3. However, when r is 2 or 3, the plurality of X ¹ and R ^f7 may be the same or different.

Examples of the (r + 1) -valent linking group represented by R ^f6 include a linear or branched hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, and carbon. An aromatic hydrocarbon group of 6 to 30 or a combination of these groups and one or more groups selected from the group consisting of oxygen atom, sulfur atom, ether group, ester group, carbonyl group, imino group and amide group Groups. The (r + 1) -valent linking group may have a substituent.

  Examples of the linear or branched hydrocarbon group having 1 to 30 carbon atoms include hydrocarbon groups such as methane, ethane, propane, butane, pentane, hexane, heptane, decane, icosane, and triacontane (r + 1). ) Groups from which a single hydrogen atom is removed.

Examples of the alicyclic hydrocarbon group having 3 to 30 carbon atoms include:
As monocyclic saturated hydrocarbons, cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, methylcyclohexane, ethylcyclohexane, etc .;
As monocyclic unsaturated hydrocarbons, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclodecene, cyclopentadiene, cyclohexadiene, cyclooctadiene, cyclodecadiene, etc .;
As polycyclic saturated hydrocarbons, bicyclo [2.2.1] heptane, bicyclo [2.2.2] octane, tricyclo [5.2.1.0 ^2,6 ] decane, tricyclo [3.3.1]. ^.1,3,7 ] decane, tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecane, adamantane, etc .;
As polycyclic unsaturated hydrocarbons, bicyclo [2.2.1] heptene, bicyclo [2.2.2] octene, tricyclo [5.2.1.0 ^2,6 ] decene, tricyclo [3.3. 1.1 ^3,7 ] decene, tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] dodecene and the like, and (r + 1) hydrogen atoms are removed.

  Examples of the aromatic hydrocarbon group having 6 to 30 carbon atoms include aromatic hydrocarbon groups such as benzene, naphthalene, phenanthrene, anthracene, tetracene, pentacene, pyrene, picene, toluene, xylene, ethylbenzene, mesitylene, cumene, and the like. And groups excluding (r + 1) hydrogen atoms.

Examples of the divalent linking group having a fluorine atom represented by X ¹ include a C 1-20 divalent chain hydrocarbon group having a fluorine atom. Examples of the divalent chain hydrocarbon group include groups represented by the following formulas (X1-1) to (X1-6).

X ¹ is preferably a group represented by the above formula (X1-1) or a group represented by the formula (X1-2), and more preferably a group represented by the formula (X1-2).

Examples of the monovalent organic group represented by R ^f7 include a linear or branched hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, and 6 carbon atoms. To 30 aromatic hydrocarbon groups, or a combination of these groups and one or more groups selected from the group consisting of oxygen, sulfur, ether, ester, carbonyl, imino and amide groups Etc.

  Examples of the structural unit (f2) include a structural unit represented by the following formula (7-1), a structural unit represented by the following formula (7-2), and the like.

In the above formula (7-1), R ^f6 is a divalent linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. R ^f5 , X ¹ and R ^f7 are as defined in the above formula (7).
In the above formula (7-2), R ^f5 , X ¹ , R ^f7 and r have the same ^{meaning as} in the above formula (7). However, when r is 2 or 3, the plurality of X ¹ and R ^f7 may be the same or different.

  Examples of the structural units represented by the above formulas (7-1) and (7-2) include structural units represented by the following formulas (7-1-1) to (7-1-3), And a structural unit represented by Formula (7-2-1).

In the above formulas (7-1-1) to (7-1-3) and the formula (7-2-1), R ^f5 has the same meaning as the above formula (7).

  As the structural unit (f2), a structural unit represented by the above formula (7-1) is preferable, and a structural unit represented by the above formula (7-1-3) is more preferable.

  Examples of the monomer that gives the structural unit (f2) include (meth) acrylic acid [2- (1-ethyloxycarbonyl-1,1-difluoro-n-butyl)] ester, (meth) acrylic acid (1 , 1,1-trifluoro-2-trifluoromethyl-2-hydroxy-3-propyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4 -Butyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-5-pentyl) ester, (meth) acrylic acid 2-{[5- (1 ' , 1 ′, 1′-trifluoro-2′-trifluoromethyl-2′-hydroxy) propyl] bicyclo [2.2.1] heptyl} ester and the like. Among these, (meth) acrylic acid [2- (1-ethyloxycarbonyl-1,1-difluoro-n-butyl)] ester is preferable.

  As a content rate of a structural unit (f2), 30 mol%-90 mol% are preferable with respect to all the structural units which comprise a [E] fluorine atom containing polymer, and 50 mol%-80 mol% are more preferable.

[Other structural units]
[E] The fluorine atom-containing polymer may contain other structural units other than the structural unit (f1) and the structural unit (f2). Examples of other structural units include the structural unit (I) of [A] polymer.

  The content ratio of the other structural units is preferably 5 mol% to 90 mol%, more preferably 10 mol% to 80 mol%, based on all the structural units constituting the [E] fluorine atom-containing polymer. More preferred is mol% to 70 mol%.

  [E] The content of the fluorine atom-containing polymer is preferably 20 parts by mass or less, more preferably 0.1 parts by mass to 15 parts by mass, and more preferably 1 part by mass to 100 parts by mass of the polymer [A]. 10 parts by mass is more preferable, and 1 part by mass to 6 parts by mass is particularly preferable. [E] If the content of the fluorine atom-containing polymer exceeds the above upper limit, the water repellency of the resist film surface becomes too high and development failure may occur.

[E] The fluorine atom content of the fluorine atom-containing polymer is preferably larger than the fluorine atom content of the [A] polymer. [E] When the fluorine atom content in the fluorine atom-containing polymer is larger than that of the [A] polymer, the [E] fluorine atom-containing polymer can be effectively unevenly distributed on the surface layer of the resist film. The water repellency of the resist film surface formed by the radiation sensitive resin composition containing the A] polymer and the [E] fluorine atom-containing polymer can be further increased. [E] The difference between the fluorine atom content of the fluorine atom-containing polymer and the fluorine atom content of the [A] polymer is preferably 1% by mass or more, and more preferably 3% by mass or more.
[E] The fluorine atom content of the fluorine atom-containing polymer is preferably 1% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, and particularly preferably 10% by mass or more.
The fluorine atom content (% by mass) can be calculated from the structure of the polymer obtained by ¹³ C-NMR.

<[E] Method for Synthesizing Fluorine Atom-Containing Polymer>
[E] The fluorine atom-containing polymer can be produced, for example, by polymerizing a monomer corresponding to each predetermined structural unit in a suitable polymerization solvent using a radical polymerization initiator.

  Examples of the radical polymerization initiator include those similar to the radical polymerization initiator used in the method for synthesizing the [A] polymer. As said polymerization solvent, the thing similar to the polymerization solvent used by the synthesis method of [A] polymer is mentioned, for example.

  As reaction temperature in the said superposition | polymerization, it is 40 to 150 degreeC normally, and 50 to 120 degreeC is preferable. The reaction time is usually 1 hour to 48 hours, preferably 1 hour to 24 hours.

  [E] The Mw of the fluorine atom-containing polymer is preferably 1,000 to 50,000, more preferably 2,000 to 30,000, and still more preferably 3,000 to 10,000. [E] When Mw of the fluorine atom-containing polymer is less than 1,000, a sufficient receding contact angle may not be obtained. On the other hand, when Mw exceeds 50,000, the developability of the resist tends to decrease.

  [E] The ratio (Mw / Mn) of Mw and Mn of the fluorine atom-containing polymer is preferably 1 to 5, and more preferably 1 to 3.

<[F] solvent>
[F] The solvent is a component for dissolving or dispersing the [A] polymer, [B] acid generator and optional components. [F] Examples of the solvent include alcohol solvents, ketone solvents, amide solvents, ether solvents, ester solvents, and the like. [F] You may use a solvent individually by 1 type or in combination of 2 or more types.

As an alcohol solvent, for example,
Methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec-pentanol, tert- Pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, sec-octanol, n- Nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, furf Alcohol, phenol, cyclohexanol, methyl cyclohexanol, 3,3,5-trimethyl cyclohexanol, benzyl alcohol, mono-alcohol solvents such as diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 -Polyhydric alcohol solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

Examples of the ketone solvent include:
Acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, di-iso- Chain ketone solvents such as butyl ketone, trimethylnonanone, 2,4-pentanedione, acetonyl acetone, diacetone alcohol, acetophenone;
And cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, and methylcyclohexanone.

As the amide solvent, for example,
Chain amide solvents such as N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropionamide;
Examples thereof include cyclic amide solvents such as N-methylpyrrolidone and N, N′-dimethylimidazolidinone.

As the ether solvent, for example,
Chain ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, diphenyl ether;
Examples thereof include cyclic ether solvents such as tetrahydrofuran and tetrahydropyran.

As the ester solvent, for example,
Methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate Acetate solvents such as 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, glycol diacetate, and methoxytriglycol acetate;
Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl acetate Acetate solvents of polyhydric alcohol partial ethers such as ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol monoethyl ether;
Carbonate solvents such as dimethyl carbonate and diethyl carbonate;
Methyl acetoacetate, ethyl acetoacetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-lactate And ester solvents of other carboxylic acids such as amyl, diethyl malonate, dimethyl phthalate, and diethyl phthalate.

  Among these, ketone solvents and ester solvents are preferable. As the ketone solvents, cyclic ketone solvents are more preferable, and cyclohexanone is more preferable. As the ester solvent, an acetate solvent of a polyhydric alcohol partial ether is more preferable, and propylene glycol monomethyl ether acetate is more preferable.

<[G] Uneven distribution promoter>
[G] The uneven distribution accelerator can be used to efficiently apply the [E] fluorine atom-containing polymer to the resist film surface when the radiation-sensitive resin composition contains the [E] fluorine atom-containing polymer. This component is unevenly distributed. When the radiation-sensitive resin composition contains [G] an uneven distribution accelerator, the [E] fluorine atom-containing polymer can be effectively unevenly distributed on the resist film surface, and as a result, [E] fluorine The amount of the atom-containing polymer used can be reduced. [G] Examples of the uneven distribution accelerator include lactone compounds, carbonate compounds, nitrile compounds, polyhydric alcohols, and the like. You may use an uneven distribution promoter individually by 1 type or in combination of 2 or more types.

  Examples of the lactone compound include γ-butyrolactone, valerolactone, mevalonic lactone, norbornane lactone, and the like.

  Examples of the carbonate compound include propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, and the like.

  Examples of the nitrile compound include succinonitrile.

  Examples of the polyhydric alcohol include glycerin.

  Of these, lactone compounds are preferred, and γ-butyrolactone is more preferred.

  [G] The content of the uneven distribution accelerator is preferably 5 to 300 parts by mass, more preferably 10 to 100 parts by mass, and 20 to 70 parts by mass with respect to 100 parts by mass of the polymer (A). Part by mass is more preferable.

<Other optional components>
The radiation-sensitive resin composition may contain other optional components such as a surfactant, an alicyclic skeleton-containing compound, and a sensitizer in addition to the components [A] to [G]. Other optional components may be used alone or in combination of two or more. Further, the content of other optional components can be appropriately determined according to the purpose.

<Method for preparing radiation-sensitive resin composition>
The radiation-sensitive resin composition is a mixture of [A] polymer, [B] acid generator, and optionally [C] other acid generator and other optional components and [F] solvent at a predetermined ratio. Can be prepared.

  As solid content concentration of the said radiation sensitive resin composition, 0.1 mass%-50 mass% are preferable, 0.5 mass%-30 mass% are more preferable, 1 mass%-10 mass% are further more preferable.

<Method for forming resist pattern>
The resist pattern forming method includes a step of forming a resist film (hereinafter also referred to as “resist film forming step”), a step of exposing the resist film (hereinafter also referred to as “exposure step”), and the exposed resist. A step of developing the film (hereinafter also referred to as “developing step”) is provided, and the resist film is formed of the radiation-sensitive resin composition. Hereinafter, each step will be described.

[Resist film forming step]
In this step, a resist film is formed using the above-described radiation-sensitive resin composition of the present invention. Although it does not specifically limit as a coating method, For example, appropriate coating means, such as spin coating, cast coating, roll coating, can be employ | adopted. Examples of the substrate include a silicon wafer and a wafer coated with aluminum. Specifically, after applying the composition so that the resulting resist film has a predetermined thickness, the solvent in the coating film is volatilized by pre-baking (PB) as necessary. As a film thickness of a coating film, 10 nm-500 nm are preferable. As temperature of PB, it is 60 to 140 degreeC normally, and 80 to 120 degreeC is preferable. The PB time is usually 5 seconds to 600 seconds, and preferably 10 seconds to 300 seconds.

  In the resist pattern molding method, in order to maximize the potential of the radiation-sensitive resin composition, for example, an organic or inorganic antireflection film can be formed on the substrate to be used. Moreover, in order to prevent the influence of the basic impurity etc. which are contained in environmental atmosphere, a protective film can also be provided on a coating film, for example. Further, when performing immersion exposure, in order to avoid direct contact between the immersion medium and the resist film, for example, an immersion protective film may be provided on the resist film.

[Exposure process]
In this step, the resist film formed in the resist film forming step is exposed. In some cases, this exposure is performed by irradiating radiation through a mask having a predetermined pattern through an immersion medium such as water. Examples of the radiation include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, EUV (wavelength 13.5 nm), X-rays, γ-rays, electron beams, α-rays, etc., depending on the line width of the target pattern. It is appropriately selected from charged particle beams and the like. Among these, when the [A] polymer of the radiation sensitive resin composition has the structural unit (I-1), far ultraviolet rays are preferable, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light, and the like. (Wavelength 248 nm) is more preferable, and ArF excimer laser light is more preferable. Moreover, when the [A] polymer of the said radiation sensitive resin composition has a structural unit (I-2) etc., an electron beam and EUV are preferable.

  Moreover, it is preferable to perform PEB (Post Exposure Bake) after exposure. By performing PEB, the dissociation reaction of the acid dissociable group in the exposed portion of the resist film can be smoothly advanced. As temperature of PEB, it is 50 to 180 degreeC normally, and 80 to 130 degreeC is preferable. The PEB time is usually 5 to 600 seconds, preferably 10 to 300 seconds.

[Development process]
In this step, the resist film exposed in the exposure step is developed. Examples of the developer used for the development include an alkali developer and an organic solvent developer. Thereby, a predetermined resist pattern is formed.

  Examples of the alkali developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, Methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4.3.0] -5-Alkaline aqueous solution in which at least one kind of alkaline compound such as nonene is dissolved.

As the organic solvent developer, for example,
Alcohol solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol;
Ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, tetrahydrofuran, dioxane, diphenyl ether, anisole;
Ketone solvents such as acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone;
Amide solvents such as N, N′-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide;
Examples include ester solvents such as diethyl carbonate, methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, and n-butyl acetate.

  These developers may be used alone or in combination of two or more. In general, after development, the substrate is washed with water or the like and dried.

<Radiation sensitive acid generator>
The radiation sensitive acid generator of the present invention comprises at least one selected from the group consisting of a partial structure represented by the above formula (1-1) and a partial structure represented by the above formula (1-2), and SO. ₃ ^- or COO ^- consisting anion, and a compound having a radiation-sensitive onium cation and a. Since the said radiation sensitive acid generator has the above-mentioned characteristic, the LWR performance etc. of the radiation sensitive resin composition containing this can be improved.

<Compound>
The compound of the present invention is represented by the above formula (A-1) or (A-2). Since the said compound has the said structure, it can be used suitably as the said radiation sensitive acid generator.

  The radiation-sensitive acid generator and the compound are described in the section [B] Acid generator of the radiation-sensitive resin composition described above.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited to these Examples. The physical properties in the examples were measured by the following methods.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
Using GPC columns (two "G2000HXL", one "G3000HXL", one "G4000HXL" from Tosoh Corporation), flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, sample concentration: 1.0% by mass, Sample injection volume: 100 μL, column temperature: 40 ° C., detector: measured by GPC using monodisperse polystyrene as a standard under the analysis conditions of a differential refractometer. The degree of dispersion (Mw / Mn) was calculated from the measurement results of Mw and Mn.

[ ¹³ C-NMR analysis]
Using a nuclear magnetic resonance apparatus (“JNM-ECX400” manufactured by JEOL Ltd.), deuterated chloroform was used as a measurement solvent, and analysis for determining the content ratio (mol%) of each structural unit in each polymer was performed.

<Synthesis of Compound (1)>
[Example 1] (Synthesis of Compound (i-1))
To a 50 mL eggplant-shaped flask were added 3.0 g (15.1 mmol) of fulvene compound (A), 15.7 g (75.6 mmol) of bromo compound (B) and 10 mL of toluene, and the mixture was heated and stirred at 110 ° C. for 120 hours. The crude product of Diels-Alder adduct (C) was obtained by distilling off the solvent and excess bromo compound (B). Purification by column chromatography gave 4.53 g (yield 74%) of compound (C).
Diels-Alder adduct (C) (4.0 g, 9.87 mmol) was dissolved in 10 mL of ethyl acetate, and this was added by syringe to a 50 mL three-necked flask containing 70 mg of Pd-C (10%) and 15 mL of ethyl acetate. Hydrogen replacement was performed. After stirring at room temperature for 40 hours, Pd—C was removed by Celite filtration and the solvent was distilled off. By purifying by column chromatography, 3.42 g (yield 85%) of hydrogenated product (D) was obtained.
In a 200 mL eggplant-shaped flask, 3.0 g (7.37 mmol) of the hydrogen adduct (D) and 30 g of acetonitrile were added and dissolved. A solution prepared by dissolving 1.86 g (22.1 mmol) of sodium hydrogen carbonate and 2.57 g (14.7 mmol) of sodium dithionite in 30 g of water was added at once, and the mixture was heated and stirred at 65 ° C. for 4 hours. . After cooling to room temperature, it was washed twice with an aqueous sodium thiosulfate solution. The organic layer was recovered, 2.51 g (22.1 mmol) of a 30% by mass aqueous hydrogen peroxide solution was added, and the mixture was heated and stirred at 55 ° C. for 6 hours. After cooling to room temperature, excess hydrogen peroxide was quenched with aqueous sodium sulfite. The organic layer was collected and the solvent was distilled off. Then, 2.20 g (7.37 mmol) of triphenylsulfonium chloride, 50 g of dichloromethane and 25 g of water were added and stirred at room temperature for 10 hours. The organic layer was washed 6 times with water, and then the solvent was distilled off to obtain 4.00 g (yield 81%) of a compound represented by the following formula (i-1).

[Examples 2 to 12] (Synthesis of compounds (i-2) to (i-12))
The precursors were appropriately selected and the same operations as in Example 1 were performed to synthesize compounds represented by the following formulas (i-2) to (i-12).

<Synthesis of [A] polymer and [E] fluorine atom-containing polymer>
The monomers used in the synthesis of each polymer in each example and comparative example are shown below.

[[A] Synthesis of polymer]
[Synthesis Example 1] (Synthesis of polymer (A-1))
7.97 g (35 mol%) of the compound (M-6), 7.44 g (45 mol%) of the compound (M-7) and 4.49 g (20 mol%) of the compound (M-8) were added to 40 g of 2-butanone. A monomer solution was prepared by adding 0.80 g of AIBN (5 mol% based on the total amount of compounds) as a radical polymerization initiator. Next, a 100 mL three-necked flask containing 20 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization reaction solution was cooled with water and cooled to 30 ° C. or lower. The cooled polymerization reaction solution was put into 400 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 80 g of methanol, filtered and dried at 50 ° C. for 17 hours to synthesize a white powdery polymer (A-1) (15.2 g, yield 76%). ). Mw of the polymer (A-1) was 7,300, and Mw / Mn was 1.53. Moreover, as a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from (M-6), (M-7) and (M-8) was 34.3 mol% and 45.1 mol%, respectively. And 20.6 mol%.

[Synthesis Example 2] (Synthesis of polymer (A-2))
6.88 g (40 mol%) of the above compound (M-1), 2.30 g (10 mol%) of the compound (M-9) and 10.83 g (50 mol%) of the compound (M-2) were converted into 40 g of 2-butanone. Then, 0.72 g of AIBN (5 mol% based on the total amount of compounds) as a radical polymerization initiator was added to prepare a monomer solution. Next, a 100 mL three-necked flask containing 20 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization reaction solution was cooled with water and cooled to 30 ° C. or lower. The cooled polymerization reaction solution was put into 400 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 80 g of methanol and then filtered and dried at 50 ° C. for 17 hours to synthesize a white powdery polymer (A-2) (14.9 g, yield 75%). ). Mw of the polymer (A-2) was 7,500, and Mw / Mn was 1.55. As a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from (M-1), (M-9) and (M-2) was 40.1 mol%, 10.1 mol%, respectively. And 49.8 mol%.

[Synthesis Example 3] (Synthesis of Polymer (A-3))
3.43 g (20 mol%) of the above compound (M-1), 3.59 g (15 mol%) of the compound (M-11), 7.83 g (40 mol%) of the compound (M-10) and the compound (M−) 8) 5.16 g (25 mol%) was dissolved in 40 g of 2-butanone, and 0.72 g of AIBN (5 mol% based on the total monomers) as a radical polymerization initiator was added to prepare a monomer solution. Next, a 100 mL three-necked flask containing 20 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization reaction solution was cooled with water and cooled to 30 ° C. or lower. The cooled polymerization reaction solution was put into 400 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed twice with 80 g of methanol, filtered and dried at 50 ° C. for 17 hours to synthesize a white powdery polymer (A-3) (15.3 g, yield 77%). ). Mw of the polymer (A-3) was 7,200, and Mw / Mn was 1.53. In addition, as a result of ¹³ C-NMR analysis, the content ratio of each structural unit derived from (M-1), (M-11), (M-10) and (M-8) was 19.5 mol%, respectively. 15.5 mol%, 40.1 mol% and 24.9 mol%.

[Synthesis Example 4] (Synthesis of Polymer (A-4))
55.0 g (65 mol%) of the above compound (M-5) and 45.0 g (35 mol%) of the compound (M-3), 4 g of AIBN as a radical polymerization initiator and 1 g of t-dodecyl mercaptan were added to 100 g of propylene glycol monomethyl ether. Then, the reaction temperature was maintained at 70 ° C. in a nitrogen atmosphere, and copolymerization was performed for 16 hours. After completion of the polymerization reaction, the polymerization reaction solution was dropped into 1,000 g of n-hexane to solidify and purify the polymer. Next, 150 g of propylene glycol monomethyl ether was added to the polymer again, and then 150 g of methanol, 34 g of triethylamine and 6 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After completion of the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the resulting polymer was dissolved in 150 g of acetone, then dropped into 2,000 g of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. It was made to dry for a period of time to obtain a white powdery polymer (A-4) (65.7 g, yield 77%). Mw of the polymer (A-4) was 7,500, and Mw / Mn was 1.90. Further, as a result of ¹³ C-NMR analysis, the content ratios of the structural unit derived from p-hydroxystyrene and the respective structural unit derived from (M-3) were 65.4 mol% and 34.6 mol%, respectively. It was.

[[E] Synthesis of fluorine atom-containing polymer]
[Synthesis Example 5] (Synthesis of Polymer (E-1))
79.9 g (70 mol%) of the above compound (M-1) and 20.91 g (30 mol%) of the compound (M-4) were dissolved in 100 g of 2-butanone to obtain dimethyl 2,2 ′ as a radical polymerization initiator. -A monomer solution was prepared by dissolving 4.77 g of azobisisobutyrate. Next, a 1,000 mL three-necked flask containing 100 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization reaction solution was cooled with water and cooled to 30 ° C. or lower. After transferring the polymerization reaction solution to a 2 L separatory funnel, the polymerization reaction solution was uniformly diluted with 150 g of n-hexane, and 600 g of methanol was added and mixed. Next, 30 g of distilled water was added, and the mixture was further stirred and allowed to stand for 30 minutes. Thereafter, the lower layer was recovered to obtain a propylene glycol monomethyl ether acetate solution containing the polymer (E-1) (yield 60%). Mw of the polymer (E-1) was 7,200, and Mw / Mn was 2.00. As a result of ¹³ C-NMR analysis, the content ratios of the structural units derived from (M-1) and (M-4) were 71.1 mol% and 28.9 mol%, respectively.

<Preparation of radiation-sensitive resin composition>
[B1] Acid generator, [B2] Acid generator, [C1] Other acid generator, [C2] Other acid generator, [D] Nitrogen atom-containing compound used for the preparation of the radiation sensitive resin composition , [F] solvent and [G] uneven distribution promoter are shown below.

[[B1] acid generator]
i-1 to i-8: Compounds represented by the above formulas (i-1) to (i-8) [[B2] acid generator]
i-9 to i-12: Compounds represented by the above formulas (i-9) to (i-12)

[[C1] Other acid generators]
C1-1: Triphenylsulfonium 2- (adamantan-1-ylcarbonyloxy) -1,1,3,3,3-pentafluoropropane-1-sulfonate (compound represented by the following formula (C1-1))
[[C2] Other acid generators]
C2-1: Triphenylsulfonium salicylate (compound represented by the following formula (C2-1))

[[D] Nitrogen atom-containing compound]
D-1: N- (undecan-1-ylcarbonyloxyethyl) morpholine (compound represented by the following formula (D-1))

[[F] solvent]
F-1: Propylene glycol monomethyl ether acetate F-2: Cyclohexanone

[[G] uneven distribution promoter]
G-1: γ-butyrolactone

[Preparation of radiation-sensitive resin composition for ArF exposure]
[Example 13]
[A] 100 parts by mass of (A-1) as a polymer, [B1] 8.5 parts by mass of (i-1) as an acid generator, [C2] (C2-1) as another acid generator 2.3 parts by weight, (E-1) 3 parts by weight as a fluorine atom-containing polymer, (F-1) 2,240 parts by weight and (F-2) 960 parts by weight as a [F] solvent And [G] (G-1) 30 mass parts as an uneven distribution promoter were mixed, and the radiation sensitive resin composition (J-1) was prepared by filtering with a membrane filter with a hole diameter of 0.2 micrometer.

[Examples 14 to 34 and Comparative Examples 1 to 6]
Each radiation-sensitive resin composition was prepared in the same manner as in Example 13 except that the components of the types and blending amounts shown in Table 1 were used. “-” In Table 1 indicates that the corresponding component was not used.

[Preparation of radiation-sensitive resin composition for electron beam exposure]
[Example 35]
[A] 100 parts by mass of (A-4) as a polymer, [B1] 20 parts by mass of (i-1) as an acid generator, [C2] (C2-1) as another acid generator. 6 parts by mass, and (F-1) 4,280 parts by mass as [F] solvent and (F-2) 1,830 parts by mass are mixed and filtered through a membrane filter having a pore size of 0.2 μm. Resin composition (J-23) was prepared.

[Examples 36 to 49 and Comparative Examples 7 to 8]
Except having used each component of the kind and compounding quantity which are shown in following Table 2, it operated similarly to Example 35 and prepared each radiation sensitive resin composition. “-” In Table 2 indicates that the corresponding component was not used.

<Formation of resist pattern>
(In the case of ArF exposure)
[Formation of resist pattern (1)]
A 12-inch silicon wafer surface was coated with a composition for forming a lower antireflection film (“ARC66” from Brewer Science) using a spin coater (“CLEAN TRACK ACT12” from Tokyo Electron), and then 205 ° C. Was heated for 60 seconds to form a lower antireflection film having a thickness of 105 nm. On the lower antireflection film, each of the prepared radiation sensitive resin compositions was applied using the spin coater, and PB was performed at 90 ° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with a film thickness of 90 nm. Next, this resist film was subjected to an optical condition of NA = 1.3 and dipole (Sigma 0.977 / 0.782) using an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON). , Exposed through a 40 nm line and space (1L1S) mask pattern. After the exposure, PEB was performed at 90 ° C. for 60 seconds. Thereafter, the resist was alkali-developed using a 2.38 mass% TMAH aqueous solution as an alkali developer, washed with water, and dried to form a positive resist pattern. When this resist pattern is formed, the line width formed through a one-to-one line and space mask having a target dimension of 40 nm is defined as an optimum exposure amount. did.

[Formation of resist pattern (2)]
[Resist pattern formation (1)], except that in [Resist pattern formation (1)], organic solvent development was performed using n-butyl acetate instead of TMAH aqueous solution, and washing with water was not performed. In the same manner as described above, a negative resist pattern was formed.

(In the case of electron beam exposure)
[Formation of resist pattern (3)]
Spin coater (Tokyo Electron's “CLEAN” on the surface of 8-inch silicon wafer
TRACK ACT8 ") was applied to the prepared radiation sensitive resin composition, and PB was performed at 90 ° C for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with a film thickness of 50 nm. Next, the resist film was irradiated with an electron beam by using a simple electron beam drawing apparatus (“HL800D” manufactured by Hitachi, Ltd., output: 50 KeV, current density: 5.0 A / cm ² ). After irradiation, PEB was performed at 120 ° C. for 60 seconds. Thereafter, development was performed at 23 ° C. for 30 seconds using a 2.38 mass% TMAH aqueous solution as an alkaline developer, washed with water, and dried to form a positive resist pattern.

<Evaluation>
About the resist pattern formed using each said radiation sensitive resin composition, LWR performance, CDU performance, resolution, cross-sectional rectangularity, depth of focus, exposure margin, and MEEF performance were evaluated according to the following method. The results are shown in Table 3 and Table 4, respectively. A scanning electron microscope (Hitachi High-Technologies “S-9380”) was used for measuring the resist pattern. As comparative examples to be compared with respect to LWR performance, CDU performance, resolution, depth of focus, exposure margin and MEEF performance, Comparative Examples 1 and 26 and Examples are carried out for Examples 13 to 25 and Example 31. Comparative Example 2 for Example 28, Comparative Example 3 for Example 27 and Example 29, Comparative Example 4 for Example 30, Comparative Example 5 for Example 32, Example 33 and Example 34 About Comparative Example 6. Examples 35 to 46, 48 and 49 were referred to as Comparative Example 7 and Example 47 as Comparative Example 8. In Tables 3 and 4, “-” represents a criterion.

[LWR performance]
The resist pattern formed by irradiating the exposure amount of Eop was observed from above the pattern using the scanning electron microscope. A total of 50 line widths were measured at arbitrary points, and a 3-sigma value was obtained from the distribution of the measured values, and this was defined as LWR performance. The LWR performance indicates that the smaller the value, the smaller the backlash of the line. When the LWR performance is 10% or more (LWR performance is 90% or less) when compared with the comparative example, the LWR performance is “good” and less than 10% (LWR performance is improved). When the value was over 90%), it was evaluated as “bad”.

[CDU performance]
The resist pattern formed by irradiating the exposure amount of Eop was observed from above the pattern using the scanning electron microscope. The line width is measured at 20 points in the range of 400 nm, the average value is obtained, the average value is measured at a total of 500 points, and the 3 sigma value is obtained from the distribution of the measured values, which is taken as the CDU performance. . The CDU performance indicates that the smaller the value, the smaller the line width variation in a long cycle. When the CDU performance is improved by 10% or more (the CDU performance value is 90% or less) when the value is compared with that of the comparative example, the improvement is less than 10% (the CDU performance is improved). When the value was over 90%), it was evaluated as “bad”.

[Resolution]
The dimension of the minimum resist pattern resolved by irradiating the exposure amount of Eop was measured, and this measured value was defined as the resolution. The resolution indicates that the smaller the value, the better the pattern can be formed. When the resolution is 10% or more when the value is compared with that of the comparative example (resolution value is 90% or less), “good” and less than 10% (solution) In the case of an image quality value of more than 90%, it was evaluated as “bad”.

[Rectangularity of cross-sectional shape]
The cross-sectional shape of the resist pattern resolved by irradiating the exposure amount of Eop was observed, and the line width Lb in the middle in the height direction of the resist pattern and the line width La in the upper part of the resist pattern were measured. The rectangularity of the cross-sectional shape indicates that the closer the value is to 1, the more the resist pattern may be rectangular. The rectangularity of the cross-sectional shape is “good” when 0.9 ≦ (La / Lb) ≦ 1.1, and (La / Lb) <0.9 or 1.1 <(La / Lb). The case was evaluated as “bad”.

[Depth of focus]
In the resist pattern resolved by irradiating the exposure amount of Eop, the dimension when the focus is changed in the depth direction is observed, and the pattern dimension is 90% to 110% of the reference without any bridge or residue. The depth of entry in the depth direction was measured, and this measured value was defined as the depth of focus. The larger the value of the focal depth, the smaller the variation in the dimension of the pattern obtained when the focal position varies, and the higher the yield during device fabrication. Depth of focus is 10% or better when the value is compared with that of the comparative example (depth of focus is 110% or more), and better than 10% (depth of focus is less than 110%). ) Was evaluated as “bad”.

[Exposure margin]
In the range of the exposure amount including the Eop, the exposure amount was changed every 1 mJ / cm ² to form resist patterns, respectively, and the respective line widths were measured using the scanning electron microscope. From the relationship between the obtained line width and exposure amount, an exposure amount E (44) at which the line width becomes 44 nm and an exposure amount E (36) at which the line width becomes 36 nm are obtained, and exposure margin = (E (36) The exposure margin (%) was calculated from the equation: −E (44)) × 100 / (optimum exposure amount). The larger the value of the exposure margin, the smaller the variation in the dimension of the pattern obtained when the exposure amount fluctuates, and the higher the yield during device fabrication. When the exposure margin is 10% or more when the value is compared with that of the comparative example (exposure margin is 110% or more), it is “good” and less than 10% (exposure). When the margin value was less than 110%, it was evaluated as “bad”.

[MEEF performance]
In the resist pattern that is resolved by irradiating with the exposure amount of Eop, the line width of the resist pattern formed by using the mask pattern having the line widths of 51 nm, 53 nm, 55 nm, 57 nm, and 59 nm is plotted on the vertical axis. The slope of the straight line when the pattern size was plotted on the horizontal axis was calculated, and this was taken as the MEEF performance. The MEEF performance indicates that the closer the value is to 1, the better the mask reproducibility. When the MEEF performance is 10% or more when the value is compared with that of the comparative example (MEEF performance value is 90% or less), the MEEF performance is less than 10% (MEEF performance is improved). When the value was over 90%), it was evaluated as “bad”.

  As is apparent from the results of Tables 3 and 4, the radiation-sensitive resin compositions of the examples were subjected to LWR performance, CDU performance, resolution, cross section in the case of ArF exposure and in the case of alkali development and organic solvent development. Excellent shape rectangularity, depth of focus, exposure margin and MEEF performance. Also, in the case of electron beam exposure and alkali development, LWR performance, CDU performance, resolution, cross-sectional rectangularity, depth of focus and Excellent exposure margin. In the comparative example, each of these characteristics was inferior to that of the example, and the rectangular shape of the cross-sectional shape was also poor. In general, it is known that the electron beam exposure shows the same tendency as in the case of EUV exposure. Therefore, according to the radiation-sensitive resin composition of the example, in the case of EUV exposure. Is presumed to be excellent in LWR performance and the like.

  According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, while exhibiting excellent depth of focus, exposure margin and MEEF performance, LWR and CDU are small, have high resolution, and have a cross-sectional shape. A resist pattern having excellent rectangularity can be formed. The radiation sensitive acid generator of the present invention can be suitably used as a component of the radiation sensitive resin composition. The compound of the present invention can be suitably used as the radiation sensitive acid generator. Therefore, these can be suitably used for manufacturing processes of semiconductor devices, which are expected to be further miniaturized in the future.

Claims (12)

Containing a polymer having a structural unit containing an acid-dissociable group, and a first radiation-sensitive acid generator;
The first radiation sensitive acid generator is
An anion comprising at least one selected from the group consisting of a partial structure represented by the following formula (1-1) and a partial structure represented by the following formula (1-2), and SO ₃ ^— or COO ^— ; A radiation-sensitive resin composition comprising a compound having a radiation-sensitive onium cation.

(In formula (1-1), R ¹ is a substituted ethenylidene group having 3 to 30 carbon atoms.
Wherein (1-2), ^{R 1} is a substituted methylene bridge having a carbon number of 3 to 30. ) The radiation sensitive resin composition according to claim 1 , wherein the compound is represented by the following formula (A-1) or (A-2).

(In formulas (A-1) and (A-2), R ¹ has the same meaning as in formulas (1-1) and (1-2) above. A ⁻ is SO ₃ ^— or COO ^— . R ² is a single bond or a divalent organic group having 1 to 20 carbon atoms, and R ^f1 and R ^f2 each independently represent a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a carbon number. Q ^{1 to} Q ⁴ each independently represents a hydrogen atom, a halogen atom, a hydroxy group, or a monovalent organic group having 1 to 10 carbon atoms, or these groups. Represents a ring structure having 3 to 20 ring members constituted by two or more bonds, and Q ⁵ and Q ⁶ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or 1 having 1 to 10 carbon atoms. Valent organic groups, or these groups are combined with each other Represents a ring structure having 3 to 20 ring members configured together with carbon atoms, X ⁺ is a monovalent radiation-sensitive onium cation, a is an integer of 0 to 5. When a is 2 or more The plurality of R ^f1 and R ^f2 may be the same or different.) The formula (A-1) and (A-2) in the A ^- is SO ₃ ^- is, this SO ₃ ^- bound to a carbon atom adjacent to claim 2 ^{R f1} and ^{R f2} is a fluorine atom The radiation sensitive resin composition described in 1. A polymer having a structural unit containing an acid dissociable group, and
First radiation sensitive acid generator
Containing
The first radiation sensitive acid generator is
The radiation sensitive resin composition which consists of a compound represented by a following formula (A-1) or a following formula (A-2).

(In the formulas (A-1) and (A-2), R ¹ Are each independently a substituted methanediyl group having 3 to 30 carbon atoms. A ⁻ Is SO ₃ ⁻ Or COO ⁻ It is. R ² Is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ^f1 And R ^f2 Are each independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a fluorinated alkyl group having 1 to 20 carbon atoms. However, A ⁻ Is SO ₃ ⁻ In the case of ₃ ⁻ R bonded to the carbon atom adjacent to ^f1 And R ^f2 Is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a fluorinated alkyl group having 1 to 20 carbon atoms. Q ¹ ~ Q ⁴ Are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a monovalent organic group having 1 to 10 carbon atoms, or a ring member number of 3 to 3 constituted by a bond of two or more of these groups 20 ring structures are represented. Q ⁵ And Q ⁶ Are each independently a hydrogen atom, a halogen atom, a hydroxy group or a monovalent organic group having 1 to 10 carbon atoms, or the number of ring members composed of these groups together with the carbon atom to which they are bonded. 3 to 20 ring structures are represented. X ⁺ Is a monovalent radiation-sensitive onium cation. a is an integer of 0-5. When a is 2 or more, a plurality of R ^f1 And R ^f2 May be the same or different. ) The radiation sensitive resin composition according to any one of claims 1 to 4 , further comprising a second radiation sensitive acid generator other than the first radiation sensitive acid generator. The radiation sensitive resin composition according to any one of claims 1 to 5 , wherein the structural unit containing the acid dissociable group is represented by the following formula (2-1).

(In Formula (2-1), R ³ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Y ¹ is a monovalent acid dissociation represented by the following Formula (Y-1). Group.)

(In the formula (Y-1), R ^e1 is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or 6 to 20 carbon atoms. R ^e2 and R ^e3 are each independently a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic carbon group having 3 to 20 carbon atoms. It is a hydrogen group or represents an alicyclic structure having 3 to 20 ring members composed of these groups together with the carbon atom to which they are bonded.) It said radiation sensitive onium cation, claim from claim 1 is at least one selected from the group consisting of cations represented by the cation and the following formula represented by the following formula (X-1) (X- 2) The radiation sensitive resin composition of any one of 6 .

(In formula (X-1), R ⁹ , R ¹⁰ and R ¹¹ are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, substituted or unsubstituted carbon. .R number 6-12 aromatic hydrocarbon group, or an -OSO ₂ -R ^a or _-SO 2 -R ^B, or by more than one binding of these groups represents a constructed ring structure ^A and R ^B are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms, or A substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, k, m and n are each independently an integer of 0 to 5. R ^{9 to} R ¹¹ , R ^A and R ^B If it is more respective plurality of ^R 9 ^{to R} 11, ^{R a} and R May be different in each is the same.
In formula (X-2), R ¹² and R ¹³ are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon group having 6 to 12 carbon atoms. aromatic hydrocarbon group, represents a cyclic structure formed by two or more binding of either a -OSO ₂ -R ^C or _-SO 2 -R ^D, or their groups. R ^C and R ^D are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. i and j are each independently an integer of 0 to 5. R ^{12, R} 13, ^R when ^C and more ^{R D} are each the plurality of ^{R 12,} R 13, ^{R C} and ^{R D} may be respectively the same or different. ) Forming a resist film;
A step of exposing the resist film, and a step of developing the exposed resist film,
A resist pattern forming method of forming a radiation-sensitive resin composition according to any one of claims 7 to the resist film from claim 1. An anion comprising at least one selected from the group consisting of a partial structure represented by the following formula (1-1) and a partial structure represented by the following formula (1-2), and SO ₃ ^— or COO ^— ; A radiation-sensitive acid generator comprising a compound having a radiation-sensitive onium cation.

(In formula (1-1), R ¹ is a substituted ethenylidene group having 3 to 30 carbon atoms.
Wherein (1-2), ^{R 1} is a substituted methylene bridge having a carbon number of 3 to 30. ) The radiation sensitive acid generator according to claim 9 , wherein the compound is represented by the following formula (A-1) or (A-2).

(In formulas (A-1) and (A-2), R ¹ has the same meaning as in formulas (1-1) and (1-2) above. A ⁻ is SO ₃ ^— or COO ^— . R ² is a single bond or a divalent organic group having 1 to 20 carbon atoms, and R ^f1 and R ^f2 each independently represent a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a carbon number. Q ^{1 to} Q ⁴ each independently represents a hydrogen atom, a halogen atom, a hydroxy group, or a monovalent organic group having 1 to 10 carbon atoms, or these groups. Represents a ring structure having 3 to 20 ring members constituted by two or more bonds, and Q ⁵ and Q ⁶ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or 1 having 1 to 10 carbon atoms. Valent organic groups, or these groups are combined with each other Represents a ring structure having 3 to 20 ring members configured together with carbon atoms, X ⁺ is a monovalent radiation-sensitive onium cation, a is an integer of 0 to 5. When a is 2 or more The plurality of R ^f1 and R ^f2 may be the same or different.) A compound represented by the following formula (A-1).

(In Formula (A-1), R ¹ is a substituted etenylidene group having 3 to 30 carbon atoms. A ⁻ is SO ₃ ^— or COO ^— . R ² is a single bond or 1 to 20 carbon atoms. R ^f1 and R ^f2 are each independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a fluorinated alkyl group having 1 to 20 carbon atoms. ^{1 to} Q ⁴ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a monovalent organic group having 1 to 10 carbon atoms, or constituted by a bond of two or more of these groups. Represents a ring structure having 3 to 20 ring members, X ⁺ is a monovalent radiation-sensitive onium cation, a is an integer of 0 to 5. When a is 2 or more, a plurality of R ^f1 and R ^f2 may be the same or different. A compound represented by the following formula (A-2).

(In Formula (A-2), R ¹ is a substituted methanediyl group having 3 to 30 carbon atoms. A ⁻ is SO ₃ ^— or COO ^— . R ² is a single bond or 1 to 20 carbon atoms. R ^f1 and R ^f2 are each independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 20 carbon atoms, or a fluorinated alkyl group having 1 to 20 carbon atoms. ⁵ and Q ⁶ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a monovalent organic group having 1 to 10 carbon atoms, or these groups are combined with each other to form a carbon atom to which they are bonded. Represents a ring structure having 3 to 20 ring members, X ⁺ is a monovalent radiation-sensitive onium cation, a is an integer of 0 to 5. When a is 2 or more, a plurality of R ^f1 And R ^f2 may be the same or different. )