JP6756120B2 - 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 micromachining by lithography include 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). , An acid is generated in the exposed part by irradiation with a charged particle beam such as an electron beam, and a chemical reaction using this acid as a catalyst causes a difference in the dissolution rate of the exposed part and the unexposed part in the developing solution, and the substrate. A resist pattern is formed on the top. At present, the resist pattern processing technology is being refined by using laser light or electron beam having a shorter wavelength and by using an immersion exposure apparatus or the like.

Along with this, the radiation-sensitive resin composition is not only excellent in the resolution of the resist pattern and the rectangularity of the cross-sectional shape, but also has LWR (Line Width Exposure) performance, CDU (Critical Exposure Uniformity) performance, and EL ( It is required to have excellent exposure rectangle (exposure tolerance) performance, development defect suppressing property, film shrinkage suppressing property after PEB (post-exposure baking), and the like. The radiation-sensitive resin composition is also required to have good storage stability. In response to these demands, the types and molecular structures of acid generators, acid diffusion control agents and other components used in radiation-sensitive resin compositions have been studied in detail (Japanese Patent Laid-Open No. 11-125907). (Refer to JP-A-8-146610 and JP-A-2000-298347).

However, in the present situation where the refinement of the resist pattern has progressed to the level of the line width of 45 nm or less, the required level of the above performance is further increased, and the above-mentioned conventional radiation-sensitive resin composition satisfies these requirements. I haven't been able to let you.

Japanese Unexamined Patent Publication No. 11-12507 Japanese Unexamined Patent Publication No. 8-146610 Japanese Unexamined Patent Publication No. 2000-298347

The present invention has been made based on the above circumstances, and is also referred to as LWR performance, CDU performance, EL performance, development defect suppressing property, and film shrinkage suppressing property after PEB (hereinafter, also referred to as "LWR performance and the like"). ) Is an object of the present invention to provide a radiation-sensitive resin composition excellent in).

（式（１）中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４は、それぞれ独立して、水素原子又は炭素数１〜２０のフッ素原子を含まない１価の有機基である。Ｒ^５及びＲ^６は、それぞれ独立して、水素原子又は炭素数１〜２０の１価の有機基である。Ｒ^７は、炭素数１〜２０のフッ素原子を含むｎ価の有機基である。Ｒ^１とＲ^２、Ｒ^１とＲ^３、Ｒ^１とＲ^５、Ｒ^３とＲ^４、Ｒ^３とＲ^５又はＲ^５とＲ^６は、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の脂環構造を表してもよい。Ｘ^＋は、１価の感放射線性オニウムカチオンである。Ｙ⁻は、ＳＯ_３ ⁻又はＣＯＯ⁻である。ｎは、１又は２である。ｎが２の場合、２のＲ^１は同一でも異なっていてもよく、２のＲ^２は同一でも異なっていてもよく、２のＲ^３は同一でも異なっていてもよく、２のＲ^４は同一でも異なっていてもよく、２のＲ^５は同一でも異なっていてもよく、２のＲ^６は同一でも異なっていてもよく、２のＸ^＋は同一でも異なっていてもよく、２のＹ⁻は同一でも異なっていてもよい。） The invention made to solve the above problems is a radiation-sensitive resin composition containing a polymer having a first structural unit containing an acid dissociative group, a compound represented by the following formula (1), and a solvent. It is a thing.

(In the formula ^{(1), R 1, R} 2, R 3 and ^{R 4} are each independently .R ⁵ and a monovalent organic group containing no hydrogen atom or a fluorine atom having 1 to 20 carbon atoms R ⁶ are each independently a monovalent organic group hydrogen atom or a C 1-20 .R ⁷ is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms .R ¹ and ^R 2, ^{R 1} and ^R 3, ^{R 1} and ^R 5, ^{R 3} and ^R 4, ^{R 3} and ^{R 5} or ^{R 5} and ^{R 6,} ring members formed together with the carbon atoms to bind these aligned with one another It may represent an alicyclic structure of 3 to 20. X ⁺ is a monovalent radiosensitive onium cation. Y ⁻ is SO ₃ ⁻ or COO ⁻ . N is 1 or 2. When n is 2, R ¹ of ² may be the same or different, R ² of ² may be the same or different, R ³ of 2 may be the same or different, and R ⁴ of 2 may be the same or different. 2 R ⁵ may be the same or different, 2 R ⁶ may be the same or different, 2 X ⁺ may be the same or different, 2 Y ^- it may be the same or different).

Another invention made to solve the above problems includes a step of applying the radiation-sensitive resin composition to one surface side of the substrate, and a step of exposing the resist film obtained by the above coating. This is a resist pattern forming method including a step of developing the exposed resist film.

（式（１）中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４は、それぞれ独立して、水素原子又は炭素数１〜２０のフッ素原子を含まない１価の有機基である。Ｒ^５及びＲ^６は、それぞれ独立して、水素原子又は炭素数１〜２０の１価の有機基である。Ｒ^７は、炭素数１〜２０のフッ素原子を含むｎ価の有機基である。Ｒ^１とＲ^２、Ｒ^１とＲ^３、Ｒ^１とＲ^５、Ｒ^３とＲ^４、Ｒ^３とＲ^５又はＲ^５とＲ^６は、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の脂環構造を表してもよい。Ｘ^＋は、１価の感放射線性オニウムカチオンである。Ｙ⁻は、ＳＯ_３ ⁻又はＣＯＯ⁻である。ｎは、１又は２である。ｎが２の場合、２のＲ^１は同一でも異なっていてもよく、２のＲ^２は同一でも異なっていてもよく、２のＲ^３は同一でも異なっていてもよく、２のＲ^４は同一でも異なっていてもよく、２のＲ^５は同一でも異なっていてもよく、２のＲ^６は同一でも異なっていてもよく、２のＸ^＋は同一でも異なっていてもよく、２のＹ⁻は同一でも異なっていてもよい。） Yet another invention made to solve the above problems is a radiation-sensitive acid generator represented by the following formula (1).

(In the formula ^{(1), R 1, R} 2, R 3 and ^{R 4} are each independently .R ⁵ and a monovalent organic group containing no hydrogen atom or a fluorine atom having 1 to 20 carbon atoms R ⁶ are each independently a monovalent organic group hydrogen atom or a C 1-20 .R ⁷ is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms .R ¹ and ^R 2, ^{R 1} and ^R 3, ^{R 1} and ^R 5, ^{R 3} and ^R 4, ^{R 3} and ^{R 5} or ^{R 5} and ^{R 6,} ring members formed together with the carbon atoms to bind these aligned with one another It may represent an alicyclic structure of 3 to 20. X ⁺ is a monovalent radiosensitive onium cation. Y ⁻ is SO ₃ ⁻ or COO ⁻ . N is 1 or 2. When n is 2, R ¹ of ² may be the same or different, R ² of ² may be the same or different, R ³ of 2 may be the same or different, and R ⁴ of 2 may be the same or different. 2 R ⁵ may be the same or different, 2 R ⁶ may be the same or different, 2 X ⁺ may be the same or different, 2 Y ^- it may be the same or different).

（式（１）中、Ｒ^１、Ｒ^２、Ｒ^３及びＲ^４は、それぞれ独立して、水素原子又は炭素数１〜２０のフッ素原子を含まない１価の有機基である。Ｒ^５及びＲ^６は、それぞれ独立して、水素原子又は炭素数１〜２０の１価の有機基である。Ｒ^７は、炭素数１〜２０のフッ素原子を含むｎ価の有機基である。Ｒ^１とＲ^２、Ｒ^１とＲ^３、Ｒ^１とＲ^５、Ｒ^３とＲ^４、Ｒ^３とＲ^５又はＲ^５とＲ^６は、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の脂環構造を表してもよい。Ｘ^＋は、１価の感放射線性オニウムカチオンである。Ｙ⁻は、ＳＯ_３ ⁻又はＣＯＯ⁻である。ｎは、１又は２である。ｎが２の場合、２のＲ^１は同一でも異なっていてもよく、２のＲ^２は同一でも異なっていてもよく、２のＲ^３は同一でも異なっていてもよく、２のＲ^４は同一でも異なっていてもよく、２のＲ^５は同一でも異なっていてもよく、２のＲ^６は同一でも異なっていてもよく、２のＸ^＋は同一でも異なっていてもよく、２のＹ⁻は同一でも異なっていてもよい。） Yet another invention made to solve the above problems is a compound represented by the following formula (1).

(In the formula ^{(1), R 1, R} 2, R 3 and ^{R 4} are each independently .R ⁵ and a monovalent organic group containing no hydrogen atom or a fluorine atom having 1 to 20 carbon atoms R ⁶ are each independently a monovalent organic group hydrogen atom or a C 1-20 .R ⁷ is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms .R ¹ and ^R 2, ^{R 1} and ^R 3, ^{R 1} and ^R 5, ^{R 3} and ^R 4, ^{R 3} and ^{R 5} or ^{R 5} and ^{R 6,} ring members formed together with the carbon atoms to bind these aligned with one another It may represent an alicyclic structure of 3 to 20. X ⁺ is a monovalent radiosensitive onium cation. Y ⁻ is SO ₃ ⁻ or COO ⁻ . N is 1 or 2. When n is 2, R ¹ of ² may be the same or different, R ² of ² may be the same or different, R ³ of 2 may be the same or different, and R ⁴ of 2 may be the same or different. 2 R ⁵ may be the same or different, 2 R ⁶ may be the same or different, 2 X ⁺ may be the same or different, 2 Y ^- it may be the same or different).

（式（ｉ）中、Ｒ^１〜Ｒ^７、Ｙ⁻及びｎは、上記式（１）と同義である。Ｍは、ａ価の金属カチオンである。ａは、１又は２である。ｈは、１又は２である。但し、ａ×ｈ＝ｎを満たすものとする。）
Yet another invention made to solve the above problems is a compound represented by the following formula (i).

(In formula (i), R ^{1 to} R ⁷ , Y ⁻ and n are synonymous with the above formula (1). M is an a-valent metal cation. A is 1 or 2. h. Is 1 or 2. However, it is assumed that a × h = n is satisfied.)

Here, the "organic group" means a group containing at least one carbon atom. The "acid dissociative group" is a group that replaces a hydrogen atom such as a carboxy group or a hydroxy group, and means a group that dissociates by the action of an acid. Further, the “number of ring members” refers to the number of atoms constituting the ring in the alicyclic structure, the aromatic ring structure, the aliphatic heterocyclic structure or the aromatic heterocyclic structure.

According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, the radiation-sensitive resin composition of the present invention has LWR performance, CDU performance, EL performance, development defect inhibitory property, and film shrinkage inhibitory property after PEB. Excellent for. The compound of the present invention can be suitably used as a component of the radiation-sensitive resin composition. Therefore, the radiation-sensitive resin composition can be suitably used for the production of semiconductor devices, which are expected to be further miniaturized in the future.

<Radiation-sensitive resin composition>
The radiation-sensitive resin composition contains the [A] polymer, the [B] compound, and the [C] solvent. The radiation-sensitive resin composition has, as suitable components, a polymer having a higher mass content of fluorine atoms than the [D] other acid generator, the [E] nitrogen-containing compound, and the [A] polymer (hereinafter, "" It may also contain (also referred to as "F] polymer"). Further, the radiation-sensitive resin composition may contain other optional components as long as the effects of the present invention are not impaired. By having the above-mentioned constitution, the radiation-sensitive resin composition has LWR performance, CDU performance, EL performance, development defect suppressing property, and film shrinkage suppressing property after PEB (hereinafter, these performances are collectively referred to as "LWR performance, etc." Also called) is excellent. Hereinafter, each component will be described.

<[A] Polymer>
[A] The polymer is a polymer having a structural unit (I). According to the radiation-sensitive resin composition, the acid dissociative group of the [A] polymer in the exposed portion is dissociated by the acid generated from the [B] compound or the like by irradiation with radiation, and the exposed portion and the unexposed portion are separated. There is a difference in solubility in the developer, and as a result, a resist pattern can be formed. The polymer [A] is usually the base polymer in the radiation-sensitive resin composition. The "base polymer" is a polymer having the highest content among the polymers constituting the resist pattern, and preferably occupies 50% by mass or more, more preferably 60% by mass or more.

[A] In addition to the structural unit (I), the polymer is a structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure or a combination thereof (hereinafter, also referred to as “structural unit (II)”), and a phenolic hydroxyl group. It is preferable to have a structural unit containing (hereinafter, also referred to as “structural unit (III)”) and / or a structural unit containing an alcoholic hydroxyl group (hereinafter, also referred to as “structural unit (IV)”). It may have other structural units other than I) to (IV). [A] The polymer may have one or more of these structural units.

[Structural unit (I)]
The structural unit (I) is a structural unit containing an acid dissociative group. Examples of the structural unit (I) include structural units represented by the following formulas (2) and (3) (hereinafter, also referred to as “structural unit (I)”). The polymer [A] may have one or more structural units (I). Hereinafter, the structural unit (I) will be described.

In the above formula (2), ^RA1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. ^RA2 is a monovalent hydrocarbon group having 1 to 20 carbon atoms. ^RA3 and ^RA4 are independently monovalent hydrocarbon groups having 1 to 20 carbon atoms, or have 3 to 20 ring members composed of carbon atoms in which these groups are combined with each other and bonded to each other. Represents the ring structure of.

In the above formula (3), ^RA1 is synonymous with the above formula (2). L ^p is a single bond, -COO- or -CONH-. R ^m is a monovalent organic group having 1 to 20 carbon atoms. c is an integer from 0 to 4. When c is 2 or more, a plurality of R ^m may be the same or different. ^RA5 , ^RA6, and ^RA7 are independently monovalent hydrocarbon groups having 1 to 20 carbon atoms or monovalent oxyhydrocarbon groups having 1 to 20 carbon atoms.

"Hydrocarbon groups" include chain hydrocarbon groups, alicyclic hydrocarbon groups and aromatic hydrocarbon groups. This "hydrocarbon group" may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The "chain hydrocarbon group" refers to a hydrocarbon group that does not contain a cyclic structure and is composed only of a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. The "alicyclic hydrocarbon group" refers to a hydrocarbon group containing only an alicyclic structure as a ring structure and not containing an aromatic ring structure, and is a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Contains both hydrocarbon groups. However, it does not have to be composed only of an alicyclic structure, and a chain structure may be included as a part thereof. The "aromatic hydrocarbon group" refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it does not have to be composed only of an aromatic ring structure, and a chain structure or an alicyclic structure may be included as a part thereof.

As ^RA1 , a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable, from the viewpoint of copolymerizability of the monomer giving the structural unit (I).

R ^{A2, R A3} and Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by ^{R A4,} for example, a monovalent chain-like hydrocarbon group having 1 to 20 carbon atoms, 1 to 20 carbon atoms Examples thereof include a valent alicyclic hydrocarbon group and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include an alkyl group such as a methyl group, an ethyl group, an n-propyl group and an i-propyl group;
Alkenyl groups such as ethenyl group, propenyl group, butenyl group;
Examples thereof include an alkynyl group such as an ethynyl group, a propynyl group and a butynyl group. Among these, an alkyl group is preferable, an alkyl group having 1 to 4 carbon atoms is more 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 include a monocyclic cycloalkyl group such as a cyclopentyl group and a cyclohexyl group;
Monocyclic cycloalkenyl groups such as cyclopentenyl group and cyclohexenyl group;
Polycyclic cycloalkyl groups such as norbornyl group, adamantyl group, tricyclodecyl group;
Examples thereof include a polycyclic cycloalkenyl group 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 include an aryl group such as a phenyl group, a tolyl group, a xylyl group, a mesityl group, a naphthyl group, a methylnaphthyl group, an anthryl group and a methylanthryl group;
Examples thereof include an aralkyl group such as a benzyl group, a phenethyl group, a naphthylmethyl group and an anthrylmethyl group.

The alicyclic structure of R ^A3 and a 3 to 20 carbon atoms with the carbon atom to which R ^A4 is combined they are bound together, for example, cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a norbornane structure, adamantane Alicyclic structure such as structure;
Aliphatic heterocyclic structures such as an oxacyclopentane structure, a thiacyclopentane structure, and an azacyclopentane structure can be mentioned. Of these, the alicyclic structure is preferable, and the cyclohexane structure is more preferable.

The structural unit (I) is, for example, a structural unit represented by the following formulas (2-1) to (2-6) and (3-1) (hereinafter, "structural unit (I-1) to (I-7)". ) ”), Etc. can be mentioned.

In the above formula ^{(2-1) ~ (2-6),} R A1 ~R A4 is as defined in the above formula (2).
In the above equation (2-1), i is an integer of 1 to 4.
In the above equation (2-3), j is an integer of 1 to 4.
In the above formula (2-6), ^RA2' , ^RA3', and ^RA4'are independently monovalent hydrocarbon groups having 1 to 20 carbon atoms.
In the above formula (3-1), ^RA1 , ^RA5 , ^RA6 and ^RA7 are synonymous with the above formula (3).

As i and j, 1 to 3 are preferable, and 1 and 2 are more preferable.

As the structural unit (I), structural units (I-1) to (I-5) are preferable.

Examples of the structural unit (I) include a structural unit represented by the following formula.

In the above formula, ^RA1 is synonymous with the above formula (2).

The structural unit (I) is a structural unit derived from 1-alkyl-monocyclic cycloalkane-1-yl (meth) acrylate and a structure derived from 2-alkyl-polycyclic cycloalkane-2-yl (meth) acrylate. Units and structural units derived from 2- (cycloalkane-yl) propan-2-yl (meth) acrylate are preferred, and structural units derived from 1-i-propylcyclopentane-1-yl (meth) acrylate, 1- Structural unit derived from methylcyclohexane-1-yl (meth) acrylate, structural unit derived from 2-ethyl-adamantan-2-yl (meth) acrylate, 2-ethyl-tetracyclododecane-2-yl (meth) acrylate Derived from structural units derived from 2- (adamantane-1-yl) propan-2-yl (meth) acrylate and derived from 2- (cyclohexane-1-yl) propan-2-yl (meth) acrylate The structural unit to be used is more preferable.

As the lower limit of the content ratio of the structural unit (I), 10 mol% is preferable, 20 mol% is more preferable, 30 mol% is further preferable, and 40 mol% is more preferable with respect to all the structural units constituting the polymer [A]. % Is particularly preferable. The upper limit of the content ratio is preferably 80 mol%, more preferably 75 mol%, further preferably 70 mol%, and particularly preferably 60 mol%. By setting the content ratio of the structural unit (I) within the above range, the LWR performance and the like of the radiation-sensitive resin composition can be further improved.

[Structural unit (II)]
The structural unit (II) is a structural unit containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof. The polymer [A] has a structural unit (II) in addition to the structural unit (I), so that the solubility in a developing solution can be adjusted more appropriately, and as a result, the radiation-sensitive resin composition. The LWR performance of the object can be further improved. In addition, the adhesion between the resist pattern formed from the radiation-sensitive resin composition and the substrate can be improved.

Examples of the structural unit (II) include a structural unit represented by the following formula.

In the above formula, ^RL1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

As the structural unit (II), a structural unit having a lactone structure, a structural unit having a cyclic carbonate structure, and a structural unit having a sultone structure are preferable, and a structural unit derived from a lactone structure-containing (meth) acrylate and a cyclic carbonate structure-containing ( Structural units derived from meta) acrylates and sultone structure-containing (meth) acrylates are more preferred, and structural units derived from norbornan lactone-yl (meth) acrylate, derived from cyanonorbornan lactone-yl (meth) acrylate. Structural unit, structural unit derived from norbornan lactone-yloxycarbonylmethyl (meth) acrylate, structural unit derived from γ-butyrolactone-yl (meth) acrylate, structural unit derived from ethylene carbonate-ylmethyl (meth) acrylate, and Structural units derived from norbornansultone-yl (meth) acrylate are more preferred.

When the polymer [A] has a structural unit (II), the lower limit of the content ratio of the structural unit (II) is preferably 10 mol%, preferably 20 mol%, based on the total structural units in the [A] polymer. Is more preferable, 30 mol% is further preferable, and 40 mol% is particularly preferable. As the upper limit of the content ratio, 80 mol% is preferable, 70 mol% is more preferable, 65 mol% is further preferable, and 60 mol% is particularly preferable. By setting the content ratio of the structural unit (II) in the above range, the solubility of the polymer [A] in the developing solution can be adjusted more appropriately, and as a result, the LWR of the radiation-sensitive resin composition is obtained. Performance and the like can be further improved. Further, the adhesion between the obtained resist pattern and the substrate can be further improved.

[Structural unit (III)]
The structural unit (III) is a structural unit containing a phenolic hydroxyl group. When KrF excimer laser light, EUV, electron beam, or the like is used as the radiation to be irradiated in the exposure step in the resist pattern forming method, the sensitivity can be further increased by having the [A] polymer having the structural unit (III). Can be done.

Examples of the structural unit (III) include a structural unit represented by the following formula (r) (hereinafter, also referred to as “structural unit (III)”).

In the above formula (4), R ¹⁴ is a hydrogen atom or a methyl group. R ¹⁵ is a monovalent organic group having 1 to 20 carbon atoms. p is an integer from 0 to 3. When p is 2 or 3, the plurality of R ^15s may be the same or different. q is an integer of 1-3. However, p + q is 5 or less.

The R ¹⁴ is preferably a hydrogen atom from the viewpoint of copolymerizability of the monomer giving the structural unit (III).

The monovalent organic group having 1 to 20 carbon atoms represented by ^{R 15,} for example, a monovalent chain-like hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon having 3 to 20 carbon atoms Hydrogen groups, monovalent aromatic hydrocarbon groups with 6 to 20 carbon atoms, -CO-, -CS-, -O-, -S- or -NR "-or these between the carbons of these groups. Examples thereof include a group containing a group in which two or more of them are combined, a group in which a part or all of the hydrogen atoms of these groups are substituted with a substituent, and the like. R "is a hydrogen atom or a monovalent organic group. is there. Among these, a monovalent chain hydrocarbon group is preferable, an alkyl group is more preferable, and a methyl group is further preferable.

The p is preferably an integer of 0 to 2, more preferably 0 and 1, and even more preferably 0.

As the above q, 1 and 2 are preferable, and 1 is more preferable.

The structural unit (III) is, for example, a structural unit represented by the following formulas (4-1) to (4-4) (hereinafter, also referred to as “structural unit (III-1) to (III-4)”) and the like. Can be mentioned.

In the above formulas (4-1) to (4-4), R ¹⁴ has the same meaning as the above formula (4).

As the structural unit (III), the structural unit (III-1) and the structural unit (III-2) are preferable, and the structural unit (III-1) is more preferable.

When the [A] polymer has a structural unit (III), the lower limit of the content ratio of the structural unit (III) is preferably 10 mol%, preferably 20 mol%, based on all the structural units constituting the [A] polymer. Mol% is more preferred, 30 mol% is even more preferred, and 40 mol% is particularly preferred. As the upper limit of the content ratio, 90 mol% is preferable, 80 mol% is more preferable, 75 mol% is further preferable, and 70 mol% is particularly preferable. By setting the content ratio of the structural unit (III) in the above range, the sensitivity of the radiation-sensitive resin composition can be further improved.

The structural unit (III) is obtained by polymerizing a monomer in which the hydrogen atom of the −OH group of hydroxystyrene is replaced with an acetyl group or the like, and then hydrolyzing the obtained polymer in the presence of a base such as amine. It can be formed by carrying out a reaction or the like.

[Structural unit (IV)]
The structural unit (IV) is a structural unit containing an alcoholic hydroxyl group. Since the polymer [A] has a structural unit (IV), its solubility in a developing solution can be adjusted more appropriately, and as a result, the LWR performance and the like of the radiation-sensitive resin composition are further improved. Can be made to. In addition, the adhesion of the resist pattern to the substrate can be further improved.

Examples of the structural unit (IV) include a structural unit represented by the following formula.

In the above formula, ^RL2 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

As the structural unit (IV), a structural unit containing a hydroxyadamantyl group is preferable, and a structural unit derived from 3-hydroxyadamantyl (meth) acrylate is more preferable.

When the [A] polymer has a structural unit (IV), the lower limit of the content ratio of the structural unit (IV) is preferably 5 mol% based on all the structural units constituting the [A] polymer. More preferably, mol%, more preferably 15 mol%, and particularly preferably 20 mol%. The upper limit of the content ratio is preferably 70 mol%, more preferably 65 mol%, further preferably 60 mol%, and particularly preferably 50 mol%. By setting the content ratio of the structural unit (IV) in the above range, the solubility of the polymer [A] in a developing solution can be further adjusted more appropriately, and as a result, the LWR of the radiation-sensitive resin composition is obtained. Performance and the like can be further improved. In addition, the adhesion of the resist pattern to the substrate can be further improved.

[Other structural units]
The polymer [A] may have other structural units in addition to the structural units (I) to (IV). The other structural unit includes, for example, a ketogenic carbonyl group, a cyano group, a carboxy group, a nitro group, an amino group or a combination thereof, and a non-dissociable monovalent alicyclic hydrocarbon group ( Examples include structural units derived from meta) acrylic acid esters. The upper limit of the content ratio of the other structural units is preferably 20 mol% and more preferably 10 mol% with respect to all the structural units constituting the [A] polymer.

The lower limit of the content of the polymer [A] is preferably 70% by mass, more preferably 80% by mass, and even more preferably 85% by mass, based on the total solid content of the radiation-sensitive resin composition. The “total solid content” refers to the sum of the components other than the [C] solvent in the radiation-sensitive resin composition. The radiation-sensitive resin composition may contain one or more [A] polymers.

<[A] Polymer synthesis method>
The polymer [A] can be synthesized, for example, by polymerizing a monomer giving each structural unit in an appropriate solvent using a radical polymerization initiator or the like.

Examples of the radical polymerization initiator include azobisisobutyronitrile (AIBN), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2,2'-azobis (2-cyclopropyl). Propionitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate and other azo radical initiators;
Examples thereof include peroxide-based radical initiators such as benzoyl peroxide, t-butyl hydroperoxide, and cumene hydroperoxide. Among these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferable, and AIBN is more preferable. These radical polymerization initiators can be used alone or in admixture of two or more.

Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Halogenated hydrocarbons such as chlorobutane, bromohexane, dichloroethane, hexamethylenedibromid, chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate;
Ketones such as acetone, methylethylketone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples thereof include alcohols such as methanol, ethanol, 1-propanol, 2-propanol and 4-methyl-2-pentanol. The solvent used for these polymerizations may be used alone or in combination of two or more.

The lower limit of the reaction temperature in the polymerization is preferably 40 ° C, more preferably 50 ° C. The upper limit of the reaction temperature is preferably 150 ° C., more preferably 120 ° C. The lower limit of the reaction time in the polymerization is preferably 1 hour, more preferably 2 hours. The upper limit of the reaction time is preferably 48 hours, more preferably 24 hours.

[A] The lower limit of the polystyrene-equivalent weight average molecular weight (Mw) of the polymer by gel permeation chromatography (GPC) is preferably 1,000, more preferably 3,000, still more preferably 4,000, and 5, 000 is particularly preferable. As the upper limit of the Mw, 50,000 is preferable, 30,000 is more preferable, 20,000 is further preferable, and 10,000 is particularly preferable. By setting the Mw of the polymer in the above range, the coatability of the radiation-sensitive resin composition is improved, and the ability to suppress development defects is further improved.

[A] The lower limit of the ratio of Mw (Mw / Mn) to the polystyrene-equivalent number average molecular weight (Mn) of the polymer by GPC is usually 1, preferably 1.1. As the upper limit of the above ratio, 5 is preferable, 3 is more preferable, and 2 is further preferable.

Mw and Mn of the polymer in the present specification are values measured by using GPC under the following conditions.
GPC column: For example, two "G2000HXL", one "G3000HXL" and one "G4000HXL" from Tosoh Co., Ltd. Column temperature: 40 ° C.
Elution solvent: tetrahydrofuran Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Detector: Differential Refractometer Standard Material: Monodisperse Polystyrene

<[B] Compound>
The compound [B] includes a compound represented by the following formula (1) (hereinafter, also referred to as “compound (1)”). The radiation-sensitive resin composition contains the compound [B] as an acid generator in addition to the polymer [A]. The compound [B] generates a weak acid upon exposure. The compound [B] has an effect as an acid diffusion control agent that controls the diffusion phenomenon of acids generated from the following [D] other acid generators and the like in the resist film by exposure and suppresses an unfavorable chemical reaction in a non-exposed region. Play.

In the above formula (1), R ¹ , R ² , R ³ and R ⁴ are independently monovalent organic groups containing no hydrogen atom or fluorine atom having 1 to 20 carbon atoms. R ⁵ and R ⁶ are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ¹ and R ² , R ¹ and R ³ , R ¹ and R ⁵ , R ³ and R ⁴ , R ³ and R ⁵ or R ⁵ and R ⁶ are composed of carbon atoms that are combined and bonded to each other. It may represent an alicyclic structure having 3 to 20 ring members. X ⁺ is a monovalent radiation-sensitive onium cation. Y ⁻ is SO ₃ ⁻ or COO ⁻ . n is 1 or 2. When n is 2, R ¹ of ² may be the same or different, R ² of ² may be the same or different, R ³ of 2 may be the same or different, and R ⁴ of 2 may be the same or different. 2 R ⁵ may be the same or different, 2 R ⁶ may be the same or different, 2 X ⁺ may be the same or different, 2 Y ^- it may be the same or different.

By containing the compound [B] in addition to the polymer [A], the radiation-sensitive resin composition has LWR performance, CDU performance, EL performance, development defect inhibitory property, and film shrinkage inhibitory property after PEB. Excellent. The reason why the radiation-sensitive resin composition has the above-mentioned structure and exerts the above-mentioned effect is not always clear, but it can be inferred as follows, for example. That is, the anion of the [B] compound contains an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms bonded to the second adjacent carbon from the carbon atom to which −SO ₃ ⁻ or COO ⁻ is bonded. Since this organic group has an appropriate chain length, the compound [B] has excellent sensitivity and has an appropriate acidity. As a result, the compound [B] functions well as an acid generator that generates a weak acid. Therefore, it is considered that the LWR performance, CDU performance, EL performance, development defect suppressing property, and film shrinkage suppressing property after PEB of the radiation-sensitive resin composition are improved.

The monovalent organic group containing no fluorine atom having 1 to 20 carbon atoms represented by R ^1, for example, a monovalent chain-like hydrocarbon group having 1 to 20 carbon atoms, a monovalent 3-20C Alicyclic hydrocarbon group, monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, -CO-, -CS-, -O-, -S- or -NR between carbon-carbon of these groups. "-Or a group containing a group in which two or more of these are combined, a group in which a part or all of the hydrogen atom of these groups is substituted with a substituent, etc. can be mentioned. R" is a hydrogen atom or 1 It is a valent organic group.

It is more preferable that R ¹ is a hydrogen atom or −OR ¹⁰ and R ¹⁰ is a monovalent organic group containing no hydrogen atom or a fluorine atom having 1 to 20 carbon atoms.

Examples of the monovalent organic group represented by R ² and containing no fluorine atom having 1 to 20 carbon atoms include the same group as the group mentioned in R ¹ . R ² is more preferably a hydrogen atom.

Examples of the monovalent organic group represented by R ³ and containing no fluorine atom having 1 to 20 carbon atoms include the same groups as those mentioned in R ¹ . It is more preferable that R ³ is −OR ⁸ and R ⁸ is a monovalent organic group containing no hydrogen atom or a fluorine atom having 1 to 20 carbon atoms.

Examples of the organic group represented by R ⁴ and containing no monovalent fluorine atom having 1 to 20 carbon atoms include the same group as the group mentioned in R ¹ .

The monovalent organic group having 1 to 20 carbon atoms represented by R ^5, for example, a monovalent chain-like hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon having 3 to 20 carbon atoms Hydrogen groups, monovalent aromatic hydrocarbon groups with 6 to 20 carbon atoms, -CO-, -CS-, -O-, -S- or -NR "-or these between the carbons of these groups. A group containing a group in which two or more of them are combined, a group in which some or all of the hydrogen atoms of these groups are substituted with a substituent, and a part or all of the hydrogen atoms of the above hydrocarbon group and the group are fluorine. Examples thereof include a group substituted with a monovalent heteroatom-containing group such as an atom or a nitrogen atom. R "is a hydrogen atom or a monovalent organic group.

Further, R ⁵ is −OR ⁹ , and it is more preferable that R ⁹ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ⁹ include the same groups as those mentioned in R ⁵ .

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ⁶ include the same groups as those mentioned in R ⁵ .

The n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms represented by R ^7, for example, such as carbon atoms, -O-, carbonyl group, alkylene group, alkenylene group, alkynylene group, a cycloalkylene group, Examples thereof include a group in which a part or all of the hydrogen atom of a group such as an aromatic group or a heterocyclic group is replaced with a fluorine atom.

It is more preferable that R ⁷ is an n-valent fluorinated hydrocarbon group having 1 to 10 carbon atoms. Examples of the n-valent fluorinated hydrocarbon group having 1 to 10 carbon atoms include an n-valent chain hydrocarbon group having 1 to 10 carbon atoms, an n-valent alicyclic hydrocarbon group having 3 to 10 carbon atoms, and carbon. Examples thereof include a group in which a part or all of hydrogen atoms contained in a group such as an n-valent aromatic hydrocarbon group having a number of 6 to 10 are substituted with a fluorine atom. Examples of the fluorinated hydrocarbon group having 1 to 10 carbon atoms include a fluorinated alkyl group having 1 to 10 carbon atoms. Of these, the perfluoroalkyl group is more preferred.

R ¹ and R ² , R ¹ and R ³ , R ¹ and R ⁵ , R ³ and R ⁴ , R ³ and R ⁵ or R ⁵ and R ⁶
Examples of the alicyclic structure having 3 to 20 ring members composed of carbon atoms that are combined with each other and bonded to each other include a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, and a cyclooctane structure. Cycloalkane structure of the ring;
Examples thereof include a polycyclic cycloalkane structure such as a norbornane structure, an adamantane structure, a tricyclodecane structure, and a tetracyclododecane structure. Among these, a monocyclic cycloalkane structure having 5 to 8 carbon atoms and a polycyclic cycloalkane structure having 7 to 12 carbon atoms are preferable, and a cyclopentane structure, a cyclohexane structure, a cyclooctane structure, a norbornane structure and an adamantane structure are preferable. More preferred, cyclopentane and adamantane structures are even more preferred.

Y ⁻ is SO ₃ ⁻ or COO ⁻ , with SO ₃ ⁻ being more preferred.

The monovalent radiation-sensitive onium cation represented by X ⁺ is a cation that is decomposed by the action of radiation. In the exposed portion, sulfonic acid is generated from the proton generated by the decomposition of the radiation-sensitive onium cation and the sulfonate anion of the compound (1). For example, the monovalent radiation-sensitive onium cation represented by X ⁺ includes elements such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi. Radiation-sensitive onium cations containing. Examples of the cation containing S (sulfur) as an element include a sulfonium cation and a tetrahydrothiophenium cation, and examples of the cation containing I (iodine) as an element include an iodonium cation and the like. Among these, the sulfonium cation represented by the following formula (X-1) and the iodonium cation represented by the following formula (X-2) are preferable, and the sulfonium cation represented by the following formula (X-1) is more preferable. preferable.

In the above formula (X-1), R ⁹ , R ¹⁰ and R ¹¹ are independently substituted or unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms, and substituted or unsubstituted rings. monovalent aromatic hydrocarbon group Number 6 to 12, -OSO ₂ -R ^a or _-SO 2 -R ^B or where the ring structure formed by two or more binding of these groups Represent. R ^A and R ^B are each independently a substituted or unsubstituted, straight or branched alkyl group having 1 to 12 carbon atoms, a monovalent alicyclic substituted or unsubstituted ring members 5-25 It is a hydrocarbon group or a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 12 ring members. p, q and r are each independently an integer of 0-5. When there are a plurality of R ^{9 to} R ¹¹ , R ^A and R ^B , the plurality of R ^9s may be the same or different, the plurality of R ^10s may be the same or different, and the plurality of R ^11s may be the same. may be different, the plurality of R ^a may be the same or different, a plurality of R ^B may be the same or different.

In the above formula (X-2), R ¹² and R ¹³ are independently substituted or unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms, and substituted or unsubstituted ring members 6 to 6, respectively. Represents a ring structure consisting of 12 monovalent aromatic hydrocarbon groups, -OSO _2- ^RC or -SO _2- ^RD , or a bond of two or more of these groups. ^RC and R ^D are independently substituted or unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms, and substituted or unsubstituted monovalent alicyclics having 5 to 25 ring members. It is a hydrocarbon group or a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 12 ring members. s and t are independently integers from 0 to 5. R ^{12, R} 13, when ^{R C} and ^{R D} is plural, respectively, a plurality of ^{R 12} may be the same or different, a plurality of ^{R 13} may be the same or different, and the plurality of ^{R C} in the same It may be different and the plurality of R / ^Ds may be 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, an n-butyl group and the like.

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, a t-butyl group and the like.

Examples of the unsubstituted aromatic hydrocarbon group represented by R ^{9 to} R ¹³ include an aryl group such as a phenyl group and a naphthyl group; and an aralkyl group such as a benzyl group and a phenethyl group.

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

Examples of the ^R 9 ^{to R 13,} unsubstituted, straight or branched alkyl group, a fluorinated alkyl group, an unsubstituted monovalent aromatic hydrocarbon group, -OSO ₂ -R "and -SO ₂ - R "is preferable, an alkyl fluorinated group and an unsubstituted monovalent aromatic hydrocarbon group are more preferable, and an alkyl fluorinated group is further preferable. "R" is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

As p, q and r in the above formula (X-1), integers of 0 to 2 are preferable, 0 and 1 are more preferable, and 0 is further preferable.

As s and t in the above formula (X-2), integers of 0 to 2 are preferable, 0 and 1 are more preferable, and 0 is further preferable.

Examples of the compound (1) include compounds represented by the following formulas (B-1) to (B-13) (hereinafter, also referred to as “compounds (B-1) to (B-13)”). Be done.

Among these, compound (B-1) and compound (B-12) are preferable, and compound (B-2) is more preferable.

The compound (1) can be synthesized by various synthetic methods, and a compound represented by the following formula (i) (also referred to as compound (i)) can be synthesized as an intermediate.

In the above formula (i), R ^{1 to} R ⁷ , Y ⁻ and n are synonymous with the above formula (1). M is an a-valent metal cation. a is 1 or 2. h is 1 or 2. However, it is assumed that a × h = n is satisfied.

Examples of the a-valent metal cation represented by M include Na, Li, K, Cs, Mg, Ca, Ba, Ag and the like.

For example, when the compound (1) is the compound (B-1), the compound represented by the following formula (b-2) as the intermediate compound (i) (hereinafter, “compound (b-2)””. From (also referred to as), compound (B-1) can be synthesized according to the following reaction scheme.

The intermediate compound (b-2) can be obtained by reacting the compound represented by the above formula (b-1) with sodium sulfite. The compound (B-1) can be obtained by reacting compound (b-2) with triphenylsulfonium chloride. Compounds [B] other than these can also be synthesized by using known methods.

The lower limit of the content of the compound [B] is preferably 0.1% by mass, more preferably 0.5% by mass, still more preferably 1% by mass, based on the total solid content of the radiation-sensitive resin composition. 3, 3% by mass is particularly preferable. The upper limit of the content is preferably 30% by mass, more preferably 20% by mass, further preferably 15% by mass, and particularly preferably 10% by mass, based on the total solid content. If the content of the compound [B] is less than the above lower limit, the lithography performance such as the resolution of the radiation-sensitive resin composition may deteriorate. If the content of the compound [B] exceeds the above upper limit, the sensitivity of the radiation-sensitive resin composition may decrease. Here, the "total solid content" refers to a component other than the solvent of the radiation-sensitive resin composition.

Further, as the lower limit of the content of the compound [B], 0.1 part by mass is preferable, 0.5 part by mass is more preferable, and 1 part by mass is further preferable with respect to 100 parts by mass of the polymer of [A]. 2 parts by mass is particularly preferable. The upper limit of the content is preferably 30 parts by mass, more preferably 20 parts by mass, further preferably 15 parts by mass, and particularly preferably 10 parts by mass with respect to 100 parts by mass of the polymer [A]. By setting the content of the compound [B] in the above range, the LWR performance and the like of the radiation-sensitive resin composition can be further improved.

<[C] Solvent>
The radiation-sensitive resin composition usually contains a [C] solvent. The solvent [C] is not particularly limited as long as it is a solvent capable of dissolving or dispersing at least the [A] polymer, the [B] compound, the [E] nitrogen-containing compound contained if necessary, and the like.

Examples of the [C] solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents and the like.

Examples of the alcohol solvent include aliphatic monoalcohol solvents having 1 to 18 carbon atoms such as 4-methyl-2-pentanol and n-hexanol;
An alicyclic monoalcoholic solvent having 3 to 18 carbon atoms such as cyclohexanol;
Multivalent alcohol solvent with 2 to 18 carbon atoms such as 1,2-propylene glycol;
Examples thereof include a polyhydric alcohol partial ether solvent having 3 to 19 carbon atoms such as propylene glycol monomethyl ether.

Examples of the ether solvent include dialkyl ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, and diheptyl ether;
Cyclic ether solvent such as tetrahydrofuran and tetrahydropyran;
Examples thereof include aromatic ring-containing ether solvents such as diphenyl ether and anisole.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone, ethyl-n-butyl ketone, methyl-n-hexyl ketone, and the like. Chain ketone solvents such as di-iso-butyl ketone and trimethylnonanonone:
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, and methylcyclohexanone:
Examples thereof include 2,4-pentanedione, acetonylacetone and acetophenone.

Examples of the amide solvent include cyclic amide solvents such as N, N'-dimethylimidazolidinone and N-methylpyrrolidone;
Examples thereof include chain amide solvents such as N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide and N-methylpropionamide.

Examples of the ester solvent include monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate;
Multivalent alcohol carboxylate solvent such as propylene glycol acetate;
Polyhydric alcohol partial ether carboxylate solvent such as propylene glycol monomethyl ether acetate;
Polyvalent carboxylic acid diester solvent such as diethyl oxalate;
Lactone-based solvents such as γ-butyrolactone and δ-valerolactone;
Examples thereof include carbonate solvents such as dimethyl carbonate, diethyl carbonate, ethylene carbonate and propylene carbonate.

Examples of the hydrocarbon solvent include an aliphatic hydrocarbon solvent having 5 to 12 carbon atoms such as n-pentane and n-hexane;
Examples thereof include aromatic hydrocarbon solvents having 6 to 16 carbon atoms such as toluene and xylene.

[C] As the solvent, an ester solvent and a ketone solvent are preferable, a polyhydric alcohol partial ether carboxylate solvent and a cyclic ketone solvent are more preferable, and a polyhydric alcohol partial alkyl ether acetate and cycloalkanone are further preferable. Propropylene glycol monomethyl ether acetate and cyclohexanone are particularly preferred. The radiation-sensitive resin composition may contain one or more [C] solvents.

<[D] Other acid generators>
The radiation-sensitive resin composition may contain an acid generator other than [B] compound [D] as long as the effects of the present invention are not impaired. [D] Other acid generators are substances that generate acids upon exposure. The generated acid dissociates the acid dissociative groups of the [A] polymer and the like to generate carboxy groups, hydroxy groups, etc., and the solubility of the [A] polymer in the developing solution changes. A resist pattern can be formed by the radioactive resin composition. As the content form of the other acid generator in the radiation-sensitive resin composition, even in the form of a free compound (hereinafter, appropriately referred to as “[D] other acid generator”), it is incorporated as a part of the polymer. Or both of these forms.

Examples of other acid generators include acid generators having an anion and a radiation-sensitive onium cation, and the anion does not have a structure represented by the above formula (1).

[D] Examples of other acid generators include onium salt compounds other than the compound [B], N-sulfonyloxyimide compounds, halogen-containing compounds, diazoketone compounds and the like.

Examples of the onium salt compound include sulfonium salt, tetrahydrothiophenium salt, iodonium salt, phosphonium salt, diazonium salt, pyridinium salt and the like.

[D] Specific examples of other acid generators include the compounds described in paragraphs [0080] to [0113] of JP-A-2009-134808.

[D] As the other acid generator, an acid generator represented by the following formula (r) is preferable. [D] Since the other acid generator has the following structure, the diffusion length of the acid generated by exposure in the resist film becomes more appropriate due to the interaction between the polymer and the structural unit (I). It is considered to be shortened, and as a result, the LWR performance and the depth of focus of the radiation-sensitive resin composition can be further improved.

In the above formula (r), R ^p1 is a monovalent group containing a ring structure having 6 or more ring members. R ^p2 is a divalent linking group. R ^p3 and R ^p4 are independently hydrogen atoms, fluorine atoms, monovalent hydrocarbon groups having 1 to 20 carbon atoms, or monovalent fluorinated hydrocarbon groups having 1 to 20 carbon atoms. R ^p5 and R ^p6 are independently fluorine atoms or monovalent fluorinated hydrocarbon groups having 1 to 20 carbon atoms. n ^p1 is an integer from 0 to 10. n ^p2 is an integer from 0 to 10. n ^p3 is an integer of 1 to 10. When n ^p1 is 2 or more, a plurality of R ^p2s may be the same or different. When n ^p2 is 2 or more, the plurality of R ^p3s may be the same or different, and the plurality of R ^p4s may be the same or different. When n ^p3 is 2 or more, the plurality of R ^p5s may be the same or different, and the plurality of R ^p6s may be the same or different. X ⁺ is a monovalent radiation-sensitive onium cation.

The monovalent group containing a ring structure having 6 or more ring members represented by R ^p1 includes, for example, a monovalent group including an alicyclic structure having 6 or more ring members and an aliphatic heterocyclic structure having 6 or more ring members. Examples thereof include a monovalent group, a monovalent group containing an aromatic ring structure having 6 or more ring members, and a monovalent group containing an aromatic heterocyclic structure having 6 or more ring members.

Examples of the alicyclic structure having 6 or more ring members include a monocyclic cycloalkane structure such as a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a cyclononane structure, a cyclodecane structure, and a cyclododecane structure;
Monocyclic cycloalkene structures such as cyclohexene structure, cycloheptene structure, cyclooctene structure, cyclodecene structure;
Polycyclic cycloalkane structures such as norbornane structure, adamantane structure, tricyclodecane structure, and tetracyclododecane structure;
Examples include a polycyclic cycloalkene structure such as a norbornene structure and a tricyclodecene structure.

Examples of the aliphatic heterocyclic structure having 6 or more ring members include lactone structures such as hexanolactone structure and norbornane lactone structure;
Sultone structures such as hexanosultone structure and norbornane sultone structure;
Oxygen atom-containing heterocyclic structure such as oxacycloheptane structure and oxanorbornane structure;
Nitrogen atom-containing heterocyclic structure such as azacyclohexane structure and diazabicyclooctane structure;
Examples thereof include a thiacyclohexane structure and a sulfur atom-containing heterocyclic structure having a thianorbornane structure.

Examples of the aromatic ring structure having 6 or more ring members include a benzene structure, a naphthalene structure, a phenanthrene structure, an anthracene structure and the like.

Examples of the aromatic heterocyclic structure having 6 or more ring members include an oxygen atom-containing heterocyclic structure such as a furan structure, a pyran structure, and a benzopyran structure, a nitrogen atom-containing heterocyclic structure such as a pyridine structure, a pyrimidine structure, and an indole structure. Can be mentioned.

As the lower limit of the number of ring members of the ring structure of R ^p1 , 7 is preferable, 8 is more preferable, 9 is further preferable, and 10 is particularly preferable. On the other hand, as the upper limit of the number of ring members, 15 is preferable, 14 is more preferable, 13 is further preferable, and 12 is particularly preferable. By setting the number of ring members in the above range, the diffusion length of the above-mentioned acid can be further appropriately shortened, and as a result, the LWR performance and the like of the radiation-sensitive resin composition can be further improved.

A part or all of the hydrogen atom ^{contained in} the ring structure of R ^p1 may be substituted with a substituent. Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, hydroxy group, carboxy group, cyano group, nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group and acyl group. Examples include an acyloxy group. Of these, a hydroxy group is preferable.

Among these, as R ^p1 , a monovalent group containing an alicyclic structure having 6 or more ring members and a monovalent group containing an aliphatic heterocyclic structure having 6 or more ring members are preferable, and a fat having 9 or more ring members is preferable. A monovalent group containing a ring structure and a monovalent group containing an aliphatic heterocyclic structure having 9 or more ring members are more preferable, and an adamantyl group, a hydroxyadamantyl group, a norbornanelactone-yl group, a norbornane sulton-yl group and 5- The oxo-4-oxatricyclo [4.3.1.1 ^3,8 ] undecane-yl group is more preferred, and the adamantyl group is particularly preferred.

Examples of the divalent linking group represented by R ^p2 include a carbonyl group, an ether group, a carbonyloxy group, a sulfide group, a thiocarbonyl group, a sulfonyl group, and a divalent hydrocarbon group. As the divalent linking group represented by R ^p2 , a carbonyloxy group, a sulfonyl group, an alkanediyl group and a cycloalkanediyl group are preferable, a carbonyloxy group and a cycloalkanediyl group are more preferable, and a carbonyloxy group and a norbornandyl are possible. Groups are more preferred, and carbonyloxy groups are particularly preferred.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^p3 and R ^p4 include an alkyl group having 1 to 20 carbon atoms. Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^p3 and R ^p4 include a fluorinated alkyl group having 1 to 20 carbon atoms. As R ^p3 and R ^p4 , a hydrogen atom, a fluorine atom and a fluorinated alkyl group are preferable, a fluorine atom and a perfluoroalkyl group are more preferable, and a fluorine atom and a trifluoromethyl group are further preferable.

Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^p5 and R ^p6 include a fluorinated alkyl group having 1 to 20 carbon atoms. As R ^p5 and R ^p6 , a fluorine atom and a fluorinated alkyl group are preferable, a fluorine atom and a perfluoroalkyl group are more preferable, a fluorine atom and a trifluoromethyl group are further preferable, and a fluorine atom is particularly preferable.

As n ^p1 , an integer of 0 to 5 is preferable, an integer of 0 to 3 is more preferable, an integer of 0 to 2 is further preferable, and 0 and 1 are particularly preferable.

As n ^p2 , an integer of 0 to 5 is preferable, an integer of 0 to 2 is more preferable, 0 and 1 are further preferable, and 0 is particularly preferable.

As n ^p3 , an integer of 1 to 5 is preferable, an integer of 1 to 4 is more preferable, an integer of 1 to 3 is further preferable, and 1 and 2 are particularly preferable.

The monovalent radiation-sensitive onium cation represented by X ⁺ is a cation that is decomposed by irradiation with exposure light. In the exposed part, sulfonic acid is generated from the proton generated by the decomposition of this photodegradable onium cation and the sulfonate anion. Examples of the monovalent radiation-sensitive onium cation represented by X ⁺ include a cation represented by the following formula (ra) (hereinafter, also referred to as “cation (ra)”) and the following formula (r). A cation represented by −b) (hereinafter, also referred to as “cation (rb)”), a cation represented by the following formula (rc) (hereinafter, also referred to as “cation (rc)”), etc. Can be mentioned.

In the above formula (ra), R ^B3 , R ^B4 and R ^B5 are independently substituted or unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms, substituted or unsubstituted. Represents a ring structure consisting of an aromatic hydrocarbon group having 6 to 12 carbon atoms, -OSO _2- R ^BB1 or -SO _2- R ^BB2 , or two or more of these groups combined with each other. .. R ^BB1 and R ^BB2 are independently substituted or unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms, and substituted or unsubstituted alicyclic hydrocarbon groups having 5 to 25 carbon atoms, respectively. Alternatively, it is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. b1, b2 and b3 are independently integers of 0 to 5. R ^B3 to R ^B5 and, if a plurality ^{R BB1} and ^{R BB2} are each the plurality of ^R B3 ^{to R B5} and ^{R BB1} and ^{R BB2} may each be the same or different.

In the above formula (rb), ^RB6 is a substituted or unsubstituted linear or branched alkyl group having 1 to 8 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms. Is. b4 is an integer from 0 to 7. If R ^B6 is plural, the plurality of R ^B6 may be the same or different, and plural R ^B6 may represent a constructed ring aligned with each other. ^RB7 is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. b5 is an integer from 0 to 6. If R ^B7 is plural, R ^B7 may be the same or different, and plural R ^B7 may represent a keyed configured ring structure. n _b2 is an integer from 0 to 3. ^RB8 is a single bond or a divalent organic group having 1 to 20 carbon atoms. n _b1 is an integer of 0 to 2.

In the above formula (rc), R ^B9 and R ^B10 are independently substituted or unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms, and substituted or unsubstituted carbon numbers 6 respectively. Represents a ring structure consisting of ~ 12 aromatic hydrocarbon groups, -OSO _2- R ^BB3 or -SO _2- R ^BB4 , or two or more of these groups combined with each other. R ^BB3 and R ^BB4 are independently substituted or unsubstituted linear or branched alkyl groups having 1 to 12 carbon atoms, and substituted or unsubstituted alicyclic hydrocarbon groups having 5 to 25 carbon atoms, respectively. Alternatively, it is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. b6 and b7 are independently integers of 0 to 5. ^{R B9,} R B10, R ^BB3 and when ^{R BB4} is plural respective plurality of ^{R B9, R B10, R BB3} and ^{R BB4} may have respectively the same or different.

The unsubstituted linear alkyl group represented by R ^B3 , R ^B4 , R ^B5 , R ^B6 , R ^B7 , R ^B9 and R ^B10 includes, for example, a methyl group, an ethyl group, an n-propyl group and an n-. Examples include a butyl group.

Examples of the unsubstituted branched alkyl group represented by R ^B3 , R ^B4 , R ^B5 , R ^B6 , R ^B7 , R ^B9 and R ^B10 include an i-propyl group, an i-butyl group and a sec-butyl group. , T-butyl group and the like.

Examples of the unsubstituted aromatic hydrocarbon group represented by R ^B3 , R ^B4 , R ^B5 , R ^B9 and R ^B10 include an aryl group such as a phenyl group, a tolyl group, a xsilyl group, a mesityl group and a naphthyl group;
Examples thereof include an aralkyl group such as a benzyl group and a phenethyl group.

Examples of the unsubstituted aromatic hydrocarbon group represented by ^RB6 and ^RB7 include a phenyl group, a tolyl group, a benzyl group and the like.

Examples of the divalent organic group represented by ^RB8 include a single bond or a divalent organic group having 1 to 20 carbon atoms.

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

R ^B3 , R ^B4 , R ^B5 , R ^B6 , R ^B7 , R ^B9 and R ^B10 include an unsubstituted linear or branched alkyl group, a fluorinated alkyl group, and an unsubstituted monovalent aromatic hydrocarbon. Hydrogen groups, -OSO _2- R ^BB5 and -SO _2- R ^BB5 are preferred, alkyl fluorinated groups and unsubstituted monovalent aromatic hydrocarbon groups are more preferred, and alkyl fluorinated groups are even more preferred. ^RBB5 is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

As b1, b2 and b3 in the formula (r-a), integers of 0 to 2 are preferable, 0 and 1 are more preferable, and 0 is further preferable. As b4 in the formula (rb), an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 1 is further preferable. As b5, an integer of 0 to 2 is preferable, 0 and 1 are more preferable, and 0 is further preferable. As n _b2 , 2 and 3 are preferable, and 2 is more preferable. As n _b1 , 0 and 1 are preferable, and 0 is more preferable. As b6 and b7 in the formula (rc), integers of 0 to 2 are preferable, 0 and 1 are more preferable, and 0 is further preferable.

Among these, cation (ra) and cation (rb) are preferable as X ⁺ , triphenylsulfonium cation and 1- [2- (4-cyclohexylphenylcarbonyl) propan-2-yl] tetrahydro. The thiophenium cation is more preferred.

Examples of the acid generator represented by the above formula (r) include compounds represented by the following formulas (r-1) to (r-15) (hereinafter, "compounds (r-1) to (r-15)". Also called) and the like.

In the above formulas (r-1) to (r-15), X ⁺ is a monovalent radiation-sensitive onium cation.

[D] As the other acid generator, an onium salt compound is preferable, and compounds (r-5), (r-14) and (r-15) are more preferable.

Further, as the other acid generator [D], a polymer having a structural unit represented by the following formula (7) is also preferable.

In the above formula (7), R'is a hydrogen atom or a methyl group. X ⁺ is a monovalent radiation-sensitive onium cation.

[D] The lower limit of the content of the other acid generator is preferably 0.1 part by mass, more preferably 0.5 part by mass, and further 1 part by mass with respect to 100 parts by mass of the polymer [A]. preferable. The upper limit of the content is preferably 35 parts by mass, more preferably 30 parts by mass, and even more preferably 25 parts by mass. [D] By setting the content of the other acid generator in the above range, the sensitivity and developability of the radiation-sensitive resin composition can be improved, and as a result, the LWR performance and the depth of focus can be improved. [D] As the other acid generator, one kind or two or more kinds can be used.

Further, in the radiation-sensitive resin composition, a photodisintegrating base that is exposed to exposure to generate a weak acid can also be used as the other acid generator [D] as long as the effects of the present invention are not impaired. The photodisintegrating base functions as an acid diffusion regulator. Examples of the photodisintegrating base include onium salt compounds that are decomposed by exposure and lose their acid diffusion controllability (however, those corresponding to the [B] compound are excluded). Examples of the onium salt compound include a sulfonium salt compound represented by the following formula (6-1), an iodonium salt compound represented by the following formula (6-2), and the like.

In the above formulas (6-1) and (6-2), R ^{23 to} R ²⁷ are independently hydrogen atoms, alkyl groups, alkoxy groups, hydroxy groups or halogen atoms. E ⁻ and Q ⁻ are independently anions represented by OH ⁻ , R ^β −COO ⁻ , R ^γ −SO ₃ ^−, or the following formula (6-3). ^Rβ is an alkyl group, an aryl group or an aralkyl group. R ^γ is an alkyl group or an aralkyl group.

In the formula (6-3), R ²⁸ represents a linear or branched alkyl group having 1 to 12 carbon atoms, 1 the number of linear or branched fluorinated alkyl group or a C 1 to 12 carbon atoms ~ 12 linear or branched alkoxy groups. u is an integer from 0 to 2. When u is 2, the two R ^28s may be the same or different.

Examples of the photodisintegrating base include compounds represented by the following formulas.

Among these, as the photodisintegrating base, a sulfonium salt is preferable, a triarylsulfonium salt is more preferable, and triphenylsulfonium salicylate and triphenylsulfonium 10-camphorsulfonate are further preferable.

[D] When a photodisintegrant base is contained as another acid generator, the lower limit of the content of the photodisintegrant base is preferably 0 parts by mass and 0.1 parts by mass with respect to 100 parts by mass of the [A] polymer. Parts by mass are more preferable, parts by mass of 0.3 are further preferable, and parts by mass of 0.5 are particularly preferable. The upper limit of the content is preferably 15 parts by mass, more preferably 10 parts by mass, further preferably 8 parts by mass, and particularly preferably 5 parts by mass with respect to 100 parts by mass of the polymer [A]. If the content of the other acid diffusion controller exceeds the above upper limit, the sensitivity of the radiation-sensitive resin composition may decrease.

<[E] Nitrogen-containing compound>
The radiation-sensitive resin composition may contain the [E] nitrogen-containing compound as long as the effects of the present invention are not impaired. The nitrogen-containing compound serves as an acid diffusion control agent that controls the diffusion phenomenon of acids generated from other acid generators and the like in the resist film by exposure and suppresses an unfavorable chemical reaction in a non-exposed region. It works. In addition, the storage stability of the radiation-sensitive resin composition is improved, and the resolution as a resist is further improved. Further, it is possible to suppress a change in the line width of the resist pattern due to a fluctuation in the leaving time from exposure to development processing, and a radiation-sensitive resin composition having excellent process stability can be obtained.

[E] Examples of the nitrogen-containing compound include a compound represented by the following formula (5) (hereinafter, also referred to as “nitrogen-containing compound (I)”), and a compound having two nitrogen atoms in the same molecule (hereinafter, “” Examples thereof include a nitrogen-containing compound (II)), a compound having three nitrogen atoms (hereinafter, also referred to as a nitrogen-containing compound (III)), an amide group-containing compound, a urea compound, and a nitrogen-containing heterocyclic compound. ..

In the above formula (5), R ²⁰ , R ²¹ and R ²² are independently hydrogen atoms, substituted or unsubstituted alkyl groups, cycloalkyl groups, aryl groups or aralkyl groups, respectively.

Examples of the nitrogen-containing compound (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine; aniline, 2,6-di-propyl. Examples include aromatic amines such as aniline.

Examples of the nitrogen-containing compound (II) include ethylenediamine, N, N, N', N'-tetramethylethylenediamine and the like.

Examples of the nitrogen-containing compound (III) include polyamine compounds such as polyethyleneimine and polyallylamine; and polymers such as dimethylaminoethylacrylamide.

Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone and the like. Be done.

Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tributylthiourea and the like.

Examples of the nitrogen-containing heterocyclic compound include pyridines such as pyridine and 2-methylpyridine; morpholins such as N-propylmorpholin and N- (undecylcarbonyloxyethyl) morpholin; pyrazine, pyrazole, benzimidazole and 2-phenyl. Examples thereof include imidazoles such as benzimidazole.

As the nitrogen-containing organic compound, a compound having an acid dissociative group can also be used. Examples of the nitrogen-containing organic compound having such an acid dissociative group include Nt-butoxycarbonylpiperidin, Nt-butoxycarbonylimidazole, Nt-butoxycarbonylbenzimidazole, and Nt-butoxycarbonyl-2. -Phenylbenzimidazole, N- (t-butoxycarbonyl) di-n-octylamine, N- (t-butoxycarbonyl) diethanolamine, N- (t-butoxycarbonyl) dicyclohexylamine, N- (t-butoxycarbonyl) diphenylamine , Nt-butoxycarbonyl-4-hydroxypiperidin, Nt-amyloxycarbonyl-4-hydroxypiperidin and the like.

When the radiation-sensitive resin composition contains [E] nitrogen-containing compound as [E] nitrogen-containing compound, the lower limit of the content of [E] nitrogen-containing compound is based on 100 parts by mass of [A] polymer. 0.1 part by mass is preferable, 0.3 part by mass is more preferable, and 1 part by mass is further preferable. The upper limit of the content is preferably 15 parts by mass, more preferably 10 parts by mass, and even more preferably 5 parts by mass.

<[F] polymer>
The [F] polymer is a polymer having a larger mass content of fluorine atoms than the [A] polymer. Since the [F] polymer has a higher mass content of fluorine atoms than the [A] polymer, its distribution tends to be unevenly distributed on the surface layer of the resist film when the resist film is formed due to its oil-repellent property. is there. As a result, according to the radiation-sensitive resin composition, it is possible to prevent the acid generator, the acid diffusion control agent, and the like from being eluted into the immersion medium during immersion exposure. Further, according to the radiation-sensitive resin composition, the advancing contact angle between the resist film and the immersion medium can be controlled within a desired range due to the water-repellent characteristics of the [F] polymer, and the occurrence of bubble defects can be prevented. Can be suppressed. Further, according to the radiation-sensitive resin composition, the receding contact angle between the resist film and the immersion medium becomes large, and high-speed scan exposure can be performed without leaving water droplets. By containing the [F] polymer in this way, the radiation-sensitive resin composition can form a resist film suitable for the immersion exposure method.

[F] As the lower limit of the mass content of fluorine atoms in the polymer, 1% by mass is preferable, 2% by mass is more preferable, 4% by mass is further preferable, and 7% by mass is particularly preferable. As the upper limit of the mass content, 60% by mass is preferable, 50% by mass is more preferable, 40% by mass is further preferable, and 30% by mass is particularly preferable. By setting the mass content of fluorine atoms in the above range, the uneven distribution of the [F] polymer in the resist film can be adjusted more appropriately. The mass content of fluorine atoms in the polymer can be calculated from the structure of the polymer obtained by ¹³ C-NMR spectrum measurement.

The form of the fluorine atom contained in the [F] polymer is not particularly limited and may be bonded to any of the main chain, side chain and terminal, but a structural unit containing a fluorine atom (hereinafter, “structural unit (F)””. Also referred to as). [F] The polymer preferably has a structural unit containing an acid dissociative group in addition to the structural unit (F) from the viewpoint of improving the development defect suppressing property of the radiation-sensitive resin composition. Examples of the structural unit containing an acid dissociative group include the structural unit (I) in the [A] polymer.

Further, the [F] polymer preferably has an alkali dissociative group. When the [F] polymer has an alkali dissociative group, the surface of the resist film can be effectively changed from hydrophobic to hydrophilic during alkaline development, and the ability to suppress development defects of the radiation-sensitive resin composition is further improved. To do. The "alkali dissociative group" is a group that replaces a hydrogen atom such as a carboxy group or a hydroxy group, and dissociates in an alkaline aqueous solution (for example, a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C.). Refers to the group.

The structural unit (F) includes a structural unit represented by the following formula (f-1) (hereinafter, also referred to as “structural unit (F-1)”) and a structural unit represented by the following formula (f-2). (Hereinafter, also referred to as "structural unit (F-2)") is preferable. The structural unit (F) may have one or more structural units (F-1) and structural units (F-2), respectively.

[Structural unit (F-1)]
The structural unit (F-1) is a structural unit represented by the following formula (f-1). [F] The polymer has a structural unit (F-1), so that the mass content of fluorine atoms can be adjusted.

In the above formula (f-1), ^RJ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. G is a single bond, an oxygen atom, a sulfur atom, -COO-, -SO ₂ ONH-, -CONH- or -OCONH-. R ^K is a monovalent fluorine-cycloaliphatic hydrocarbon group having a monovalent fluorinated chain hydrocarbon group or a 4 to 20 carbon atoms having 1 to 6 carbon atoms.

The R ^J, from the viewpoint of copolymerizability of the monomer giving the structural unit (F-1), preferably a hydrogen atom or a methyl group, more preferably a methyl group.

As G, -COO-, -SO ₂ ONH-, -CONH- and -OCONH- are preferable, and -COO- is more preferable.

The monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms represented by R ^K, such as trifluoromethyl group, 2,2,2-trifluoroethyl group, perfluoroethyl group, 2,2 , 3,3,3-pentafluoropropyl group, 1,1,1,3,3,3-hexafluoropropyl group, perfluoron-propyl group, perfluoroi-propyl group, perfluoron-butyl group, Examples thereof include a perfluoroi-butyl group, a perfluorot-butyl group, a 2,2,3,3,4,5,5-octafluoropentyl group and a perfluorohexyl group.

The monovalent fluorine-cycloaliphatic hydrocarbon group having 4 to 20 carbon atoms represented by R ^K, for example, monofluoromethyl cyclopentyl group, difluorocyclopentyl groups, perfluorocyclopentyl group, monofluoromethyl cyclohexyl group, difluorocyclopentyl groups , Perfluorocyclohexylmethyl group, fluoronorbornyl group, fluoroadamantyl group, fluorobornyl group, fluoroisobornyl group, fluorotricyclodecyl group, fluorotetracyclodecyl group and the like.

The R ^K, preferably a fluorinated chain hydrocarbon group, a 2,2,2-trifluoroethyl group and 1,1,1,3,3,3-hexafluoro-2-propyl group is more preferred, 2 , 2,2-Trifluoroethyl group is more preferred.

When the [F] polymer has a structural unit (F-1), the lower limit of the content ratio of the structural unit (F-1) is 10 mol% with respect to all the structural units constituting the [F] polymer. Is preferable, and 20 mol% is more preferable. The upper limit of the content ratio is preferably 90 mol%, more preferably 70 mol%, still more preferably 50 mol%. By setting the content ratio of the structural unit (F-1) in the above range, the mass content of the fluorine atom of the [F] polymer can be adjusted more appropriately.

[Structural unit (F-2)]
The structural unit (F-2) is a structural unit represented by the following formula (f-2). By having the structural unit (F-2) in the [F] polymer, the mass content of fluorine atoms can be adjusted, and the surface of the resist film can be changed from water-repellent to hydrophilic before and after alkaline development.

In the above formula (f-2), ^RC is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^D is 1 to 20 carbon atoms (s + 1) -valent hydrocarbon group, or an oxygen atom at the terminal of ^{R E} side of the hydrocarbon group, a sulfur atom, -NR'-, carbonyl group, -COO- or - It is a structure in which CONH- is bound. R'is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. ^RE is a single bond or a divalent organic group having 1 to 20 carbon atoms. W ¹ is a single bond or a divalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms. A ¹ is an oxygen atom, -NR "-, -COO- * or -SO ₂ O- *. R" is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. * Indicates a site binding to ^{R F. RF} is a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms. s is an integer of 1-3. However, when s is 1, ^RD may be a single bond. If s is 2 or 3, a plurality of ^{R E,} W ^{1, A} 1 and ^{R F} is may be respectively the same or different. If W ¹ is a single bond, R ^F is a group containing a fluorine atom.

As the ^RC , a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable, from the viewpoint of copolymerizability of the monomer giving the structural unit (F-2).

The (s + 1) -valent hydrocarbon group having 1 to 20 carbon atoms represented by R ^D, for example, monovalent hydrocarbon groups of formula (2) of ^R A2 ^{to R A4} carbon atoms exemplified as 20 Examples thereof include a group obtained by removing s hydrogen atoms from the group.

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

When s is 1, the ^RD is preferably a single bond or a divalent hydrocarbon group, more preferably a single bond or an alkanediyl group, further preferably a single bond or an alkanediyl group having 1 to 4 carbon atoms. Bonds, methanediyl groups and propanediyl groups are particularly preferred.

Examples of the divalent organic group having 1 to 20 carbon atoms represented by R ^E, for example, the formula (a-3) hydrogen from a monovalent organic group exemplified having 1 to 20 carbon atoms as ^{R 4} 1 Pcs Examples include groups excluding atoms.

The R ^E, preferably a group having a single bond and a lactone structure is more preferably a group having a single bond and a polycyclic lactone structure, a group having a single bond and norbornane lactone structure is more preferable.

Examples of the divalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms represented by W ¹ include a fluoromethanediyl group, a difluoromethanediyl group, a fluoroethanediyl group, a difluoroethanediyl group, and a tetrafluoroethanediyl group. , Hexafluoropropanediyl group, octafluorobutanediyl group and other fluorinated alcandiyl groups;
Examples thereof include a fluorinated arcendyl group such as a fluoroethanediyl group and a difluoroethendyl group. Among these, a fluorinated alkanediyl group is preferable, and a difluoromethanediyl group is more preferable.

As A ¹ , oxygen atoms, -COO- *, and -SO ₂ O- * are preferable, and -COO- * is more preferable.

The monovalent organic group having 1 to 30 carbon atoms represented by R ^F, for example, an alkali dissociative group, the acid-dissociable group, and the like hydrocarbon group having 1 to 30 carbon atoms. The R ^F, among these, alkali dissociating group is preferred. By using ^RF as an alkaline dissociative group, the surface of the resist film can be effectively changed from hydrophobic to hydrophilic during alkaline development, and the ability to suppress development defects of the radiation-sensitive resin composition is further improved. ..

If R ^F is an alkali dissociative group, the ^{R F,} the following formula (iii) ~ (v) the group represented by (hereinafter, also referred to as "group (iii) ~ (v)") is preferable.

In the above formula (iii), R ^5a and R ^5b are independently monovalent organic groups having 1 to 20 carbon atoms, or these groups are combined with each other and are composed of carbon atoms to which they are bonded. It represents an alicyclic structure having 3 to 20 ring members.

In the above formula (iv), R ^5c and R ^5d are independently monovalent organic groups having 1 to 20 carbon atoms, or these groups are combined with each other and are composed of nitrogen atoms to which they are bonded. It represents a heterocyclic structure having 3 to 20 ring members.

In the above formula (v), R ^5e is a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms.

Examples of the monovalent organic group having 1 to 20 carbon atoms and the monovalent hydrocarbon group having 1 to 20 carbon atoms include the same groups as those exemplified as R ² of the above formula (I).

As the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, for example, a part or all of the hydrogen atoms of the group exemplified as the monovalent hydrocarbon group having 1 to 20 carbon atoms are substituted with a fluorine atom. Examples include the base.

As the group (iii), a group represented by the following formulas (iii-1) to (iii-4) (hereinafter, also referred to as "group (iii-1) to (iii-4)") is a group (iv). The group represented by the following formula (iv-1) (hereinafter, also referred to as “group (iv-1)”) is represented by the following formulas (v-1) to (v-5) as the group (v). The represented group (hereinafter, also referred to as "group (v-1) to (v-5)") is preferable.

Of these, the group (v-3) and the group (v-5) are preferable.

Further, when ^RF is a hydrogen atom, the affinity of the [F] polymer with an alkaline developer is improved, which is preferable. In this case, if A ¹ is an oxygen atom and W ¹ is a 1,1,1,3,3,3-hexafluoro-2,2-methanediyl group, the above affinity is further improved.

When the [F] polymer has a structural unit (F-2), the lower limit of the content ratio of the structural unit (F-2) is 10 mol% with respect to all the structural units constituting the [F] polymer. Is preferable, 20 mol% is more preferable, and 40 mol% is further preferable. The upper limit of the content ratio is preferably 90 mol%, more preferably 85 mol%, and even more preferably 80 mol%. By setting the content ratio of the structural unit (F-2) in the above range, the surface of the resist film formed from the radiation-sensitive resin composition can be more appropriately changed from water-repellent to hydrophilic before and after alkaline development. ..

The lower limit of the content ratio of the structural unit (F) is preferably 10 mol%, more preferably 20 mol%, still more preferably 25 mol%, based on all the structural units constituting the [F] polymer. The upper limit of the content ratio is preferably 90 mol%, more preferably 85 mol%, and even more preferably 80 mol%.

The lower limit of the structural unit containing the acid dissociative group in the [F] polymer is preferably 10 mol%, more preferably 20 mol%, and more preferably 50 mol% with respect to all the structural units constituting the [F] polymer. Is even more preferable. The upper limit of the content ratio is preferably 90 mol%, more preferably 80 mol%, still more preferably 75 mol%. By setting the content ratio of the structural unit containing the acid dissociative group within the above range, the development defect suppressing property of the radiation-sensitive resin composition can be further improved.

When the radiation-sensitive resin composition contains the [F] polymer, the lower limit of the content of the [F] polymer is preferably 0.1 part by mass with respect to 100 parts by mass of the [A] polymer. , 0.5 parts by mass is more preferable, 1 part by mass is further preferable, and 2 parts by mass is particularly preferable. The upper limit of the content is preferably 30 parts by mass, more preferably 20 parts by mass, further preferably 15 parts by mass, and particularly preferably 10 parts by mass. The radiation-sensitive resin composition may contain one or more [F] polymers.

The [F] polymer can be synthesized in the same manner as the above-mentioned [A] polymer.

[F] As the lower limit of Mw of the polymer by GPC, 1,000 is preferable, 3,000 is more preferable, 4,000 is further preferable, and 5,000 is particularly preferable. As the upper limit of the Mw, 50,000 is preferable, 30,000 is more preferable, 20,000 is further preferable, and 10,000 is particularly preferable. By setting the Mw of the [F] polymer in the above range, the coatability and the ability to suppress development defects of the radiation-sensitive resin composition are improved.

The lower limit of the ratio of Mw to Mn (Mw / Mn) of the polymer by GPC is usually 1, preferably 1.2. As the upper limit of the above ratio, 5 is preferable, 3 is more preferable, and 2 is further preferable.

<Other optional ingredients>
The radiation-sensitive resin composition may contain other optional components other than the above-mentioned [A] to [E] components. Examples of other optional components include surfactants, alicyclic skeleton-containing compounds, sensitizers, and the like. These other optional components may be used alone or in combination of two or more.

[Surfactant]
Surfactants have the effect of improving coatability, striation, developability and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, and polyethylene glycol di. Nonionic surfactants such as stearate;
Commercially available products include Shin-Etsu Chemical's "KP341", Kyoeisha Chemical's "Polyflow No.75" and "No.95", and Tochem Products'"FtopEF301","Ftop303", and "Same". EF352, DIC's "Mega Fvck F171", "F173, Sumitomo 3M's" Florard FC430 "," FC431 ", Asahi Glass Industry's" Asahi Guard AG710 "," Surflon S-382 "," SC "-101", "SC-102", "SC-103", "SC-104", "SC-105", "SC-106" and the like can be mentioned. The upper limit of the content of the surfactant is preferably 2 parts by mass and more preferably 1 part by mass with respect to 100 parts by mass of the polymer [A].

[Alicyclic skeleton-containing compound]
The alicyclic skeleton-containing compound has the effect of improving dry etching resistance, pattern shape, adhesiveness to a substrate, and the like.

[Sensitizer]
The sensitizer has an action of increasing the amount of acid produced from the compound [B] or the like, and has an effect of improving the "apparent sensitivity" of the radiation-sensitive resin composition.

Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyls, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like. These sensitizers may be used alone or in combination of two or more. The upper limit of the content of the sensitizer is preferably 2 parts by mass and more preferably 1 part by mass with respect to 100 parts by mass of the polymer [A].

<Method of preparing radiation-sensitive resin composition>
The radiation-sensitive resin composition includes, for example, [A] polymer, [B] compound and [C] solvent, and optionally contained [E] nitrogen-containing compound, [F] polymer, and any other optional material. It can be prepared by mixing the components at a predetermined ratio and preferably filtering the obtained mixed solution with, for example, a filter having a pore size of about 0.2 μm. The lower limit of the solid content concentration of the radiation-sensitive resin composition is preferably 0.1% by mass, more preferably 0.5 parts by mass, still more preferably 1% by mass. The upper limit of the solid content concentration is preferably 50% by mass, more preferably 30% by mass, and even more preferably 20% by mass.

The radiation-sensitive resin composition can be used for both positive pattern formation using an alkaline developer and negative pattern formation using a developer containing an organic solvent. Of these, when used for forming a negative pattern using a developing solution containing an organic solvent, the radiation-sensitive resin composition can exhibit higher resolution.

<Resist pattern formation method>
The resist pattern forming method is a step of coating the radiation-sensitive resin composition on one surface side of a substrate (hereinafter, also referred to as a “coating step”), and exposing the resist film obtained by the above coating. It includes a step (hereinafter, also referred to as “exposure step”) and a step of developing the exposed resist film (hereinafter, also referred to as “development step”).

According to the resist pattern forming method, since the above-mentioned radiation-sensitive resin composition is used, a resist pattern excellent in LWR performance, CDU performance, EL performance, development defect suppressing property and film shrinkage suppressing property after PEB can be obtained. Can be formed. Hereinafter, each step will be described.

[Coating process]
In this step, the radiation-sensitive resin composition is applied to one surface side of the substrate. Examples of the substrate on which the resist film is formed include a silicon wafer and a wafer coated with aluminum. A resist film is formed by applying the radiation-sensitive resin composition on this substrate. The coating method of the radiation-sensitive resin composition is not particularly limited, and examples thereof include known methods such as a spin coating method. When the radiation-sensitive resin composition is applied, the amount of the radiation-sensitive resin composition to be applied is adjusted so that the resist film to be formed has a desired thickness. After the radiation-sensitive resin composition is applied onto the substrate, prebaking (hereinafter, also referred to as “PB”) may be performed to volatilize the solvent. The lower limit of the temperature of PB is preferably 30 ° C, more preferably 50 ° C. The upper limit of the temperature is preferably 200 ° C., more preferably 150 ° C. As the lower limit of the PB time, 10 seconds is preferable, and 30 seconds is more preferable. The upper limit of the time is preferably 600 seconds, more preferably 300 seconds. The lower limit of the average thickness of the resist film is preferably 10 nm, more preferably 20 nm, and even more preferably 50 nm. The upper limit of the average thickness is preferably 1,000 nm, more preferably 200 nm, and even more preferably 150 nm.

[Exposure process]
In this step, the resist film obtained by the above coating is exposed. In some cases, this exposure is performed by irradiating radiation through an immersion exposure solution such as water and a mask having a predetermined pattern.

As the immersion exposure liquid, a liquid having a refractive index larger than that of air is usually used. Specific examples thereof include pure water, long-chain or cyclic aliphatic compounds and the like. With the immersion exposure liquid passing through, that is, with the immersion exposure liquid filled between the lens and the resist film, radiation is irradiated from the exposure apparatus, and the resist film is formed through a mask having a predetermined pattern. To expose.

The radiation includes visible light, ultraviolet rays, far ultraviolet rays such as ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), and extreme ultraviolet rays, depending on the type of radiation-sensitive acid generator used. Extreme Ultraviolet (EUV), 13.5 nm), electromagnetic waves such as X-rays, charged particle beams such as electron beams and α-rays are appropriately selected and used. Among these, ArF excimer laser light and KrF excimer laser are used. Light, EUV, X-ray and electron beam are preferable, and ArF excimer laser light, EUV and electron beam are more preferable. The exposure conditions such as the exposure amount can be appropriately selected according to the compounding composition of the radiation-sensitive resin composition, the type of additive, and the like.

It is preferable that the resist film after exposure is heat-treated (hereinafter, also referred to as “post-exposure heating (post-exposure bake, PEB)”). With this PEB, the dissociation reaction of the acid dissociative group such as the polymer [A] can proceed smoothly. The heating conditions of the PEB are appropriately adjusted by the compounding composition of the radiation-sensitive resin composition, but the lower limit of the temperature of the PEB is preferably 30 ° C., more preferably 50 ° C., and even more preferably 70 ° C. The upper limit of the temperature is preferably 200 ° C, more preferably 150 ° C, and even more preferably 120 ° C. The lower limit of the PEB time is preferably 10 seconds, more preferably 30 seconds. The upper limit of the time is preferably 600 seconds, more preferably 300 seconds. In the resist pattern forming method, since the above-mentioned radiation-sensitive resin composition is used, the film shrinkage inhibitory property after PEB is excellent.

Further, in order to maximize the potential of the radiation-sensitive resin composition, for example, as disclosed in Japanese Patent Application Laid-Open No. 6-12452, Japanese Patent Application Laid-Open No. 59-93448, etc., on the substrate used. An organic or inorganic antireflection film may be formed. Further, in order to prevent the influence of basic impurities and the like contained in the environmental atmosphere, a protective film may be provided on the resist film, for example, as disclosed in Japanese Patent Application Laid-Open No. 5-188598.

[Development process]
In this step, the resist film exposed in the above exposure step is developed. Examples of the developing solution used for this development include an alkaline aqueous solution (alkaline developing solution), a solution containing an organic solvent (organic solvent developing solution), and the like. As a result, a predetermined resist pattern is formed.

Examples of the alkaline developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, and methyldiethylamine. , Ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3] .0] Examples thereof include an alkaline aqueous solution in which at least one alkaline compound such as -5-nonene is dissolved. Among these, the TMAH aqueous solution is preferable, and the 2.38 mass% TMAH aqueous solution is more preferable.

Examples of the organic solvent developing solution include organic solvents such as hydrocarbon solvents, ether solvents, ester solvents, ketone solvents and alcohol solvents, and solutions containing organic solvents. Examples of the organic solvent include one or more of the solvents exemplified as the [C] solvent of the above-mentioned radiation-sensitive resin composition. Among these, ester-based solvents and ketone-based solvents are preferable. As the ester solvent, an acetic acid ester solvent is preferable, and n-butyl acetate is more preferable. As the ketone solvent, a chain ketone is preferable, and 2-heptanone is more preferable. The lower limit of the content of the organic solvent in the organic solvent developer is preferably 80% by mass, more preferably 90% by mass, further preferably 95% by mass, and particularly preferably 99% by mass. Examples of the components other than the organic solvent in the organic solvent developer include water, silicone oil and the like.

These developers may be used alone or in combination of two or more. After development, it is generally washed with water or the like and dried.

<Radiation-sensitive acid generator>
The radiation-sensitive acid generator is a compound represented by the above formula (1). Since the radiation-sensitive acid generator has the above-mentioned properties, it can be suitably used as a component of the radiation-sensitive acid generator of the radiation-sensitive resin composition, and the LWR performance of the radiation-sensitive resin composition. , CDU performance, EL performance, development defect suppressing property and film shrinkage suppressing property after PEB can be improved.

<Compound>
The compound is represented by the above formula (1). The compound can be suitably used as the above-mentioned radiation-sensitive acid generator.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. The measurement method of various physical property values is shown below.

[Measurement of weight average molecular weight (Mw), number average molecular weight (Mn) and dispersity (Mw / Mn)]
For Mw and Mn of the polymer, a GPC column (2 "G2000HXL", 1 "G3000HXL", 1 "G4000HXL") manufactured by Tosoh Corporation was used by gel permeation chromatography (GPC) under the following conditions. It was measured. The degree of dispersion (Mw / Mn) was calculated from the measurement results of Mw and Mn.

Elution solvent: tetrahydrofuran Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Column temperature: 40 ° C
Detector: Differential Refractometer Standard Material: Monodisperse Polystyrene

[ ^{1 1} H-NMR analysis and ¹³ C-NMR analysis]
¹ H-NMR analysis and ¹³ C-NMR analysis for determining the content ratio of each structural unit of the polymer were measured using a nuclear magnetic resonance apparatus (“JNM-Delta 400” of JEOL Ltd.).

<Synthesis of [A] polymer and [F] polymer>
The monomers used in the synthesis of each polymer in each Example and Comparative Example are shown below.

The compounds (M-1), (M-4), (M-5), (M-7), (M-10), (M-11), (M-18) and (M-20) ) Is the structural unit (I), and compounds (M-2), (M-6), (M-8), (M-9), and (M-12) to (M-17) are structural units (II). ), (M-19) is the structural unit (III), (M-3) is the structural unit (IV), (M-21) is the structural unit as an acid generator, and (M-22) is. Structural units (F) are given respectively.

[Synthesis Example 1] (Synthesis of Polymer (A-1))
Compound (M-1) 7.97 g (35 mol%), compound (M-2) 7.44 g (45 mol%), and compound (M-3) 4.49 g (20 mol%) 2-butanone 40 g To prepare a monomer solution, 0.80 g of AIBN (5 mol% based on all the monomers) was added as an initiator. Next, a 100 mL three-necked flask containing 20 g of 2-butanone was purged with nitrogen for 30 minutes, heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise using a dropping funnel over 3 hours. The start of dropping was set as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was water-cooled and cooled to 30 ° C. or lower. A cooled polymerization solution was put into 400 g of methanol, and the precipitated white powder was filtered off. 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). %). The Mw of the polymer (A-1) was 7,300, and the Mw / Mn was 1.53. ¹³ As a result of C-NMR analysis, the content ratios of the structural units derived from (M-1), (M-2), and (M-3) were 34.3 mol%, 45.1 mol%, and 45.1 mol%, respectively. It was 20.6 mol%.

[Synthesis Examples 2-11, 13-14] (Synthesis of Polymers (A-2) to (A-11), (A-13) to (A-14))
Polymers (A-2) to (A-11) and (A-13) to (A-) are the same as in Synthesis Example 1, except that the types and amounts of the monomers shown in Table 1 below are used. 14) were synthesized respectively. In addition, "-" in the table indicates that the corresponding component was not used. The content ratio, yield, Mw and Mw / Mn values of each structural unit of the obtained polymer are shown in Table 1.

[Synthesis Example 12] (Synthesis of Polymer (A-12))
55.0 g (65 mol%) of compound (M-19) and 45.0 g (35 mol%) of compound (M-18), 4 g of AIBN as an initiator, and 1 g of t-dodecyl mercaptan are dissolved in 100 g of propylene glycol monomethyl ether. After that, the reaction temperature was maintained at 70 ° C. under a nitrogen atmosphere, and copolymerization was carried out for 16 hours. After completion of the polymerization reaction, the polymerization solution was added dropwise to 1,000 g of n-hexane to coagulate 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 the hydrolysis reaction was carried out for 8 hours while refluxing at the boiling point. After completion of the reaction, the solvent and triethylamine were distilled off under reduced pressure, the obtained polymer was dissolved in 150 g of acetone, and then added dropwise to 2,000 g of water to coagulate, and the produced white powder was filtered and 17 at 50 ° C. The mixture was dried for a long time to obtain a white powdery polymer (A-12) (65.7 g, yield 77%). The Mw of the polymer (A-12) was 7500, and the Mw / Mn was 1.90. ¹³ As a result of C-NMR analysis, the content ratio of each structural unit derived from (M-19) and (M-18) was 65.4 mol% and 34.6 mol%, respectively.

[Synthesis Example 15] (Synthesis of Polymer (F-1))
82.2 g (70 mol%) of compound (M-22) and 17.8 g (30 mol%) of compound (M-10) were dissolved in 200 g of 2-butanone and 0.46 g of AIBN (relative to all monomers) as an initiator. 1 mol%) was added to prepare a monomer solution. Next, a 500 mL three-necked flask containing 100 g of 2-butanone was purged with nitrogen for 30 minutes, heated to 80 ° C. with stirring, and the above-prepared monomer solution was added dropwise using a dropping funnel over 3 hours. The start of dropping was set as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was water-cooled and cooled to 30 ° C. or lower. After replacing the solvent with 400 g of acetonitrile, 100 g of hexane was added and stirred, and the operation of recovering the acetonitrile layer was repeated three times. By substituting the solvent with propylene glycol monomethyl ether acetate, a solution containing 60.1 g of the polymer (F-1) was obtained (yield 60%). The Mw of the polymer (F-1) was 15,000, and the Mw / Mn was 1.90. ¹³ As a result of C-NMR analysis, the content ratios of the structural units derived from (M-22) and (M-10) were 70.3 mol% and 29.7 mol%, respectively.

<Synthesis of [B] compound>
[Synthesis Example 16] (Synthesis of compound (B-1))
To a 300 mL round bottom flask, add 7.28 g (19.4 mmol) of the compound represented by the following formula (b-1), 19.5 g (155 mmol) of sodium sulfite, and 50 mL of water, and immerse in an oil bath at 115 ° C. 36. The mixture was heated and stirred for a period of time to synthesize a compound represented by the following formula (b-2). After cooling to room temperature, 6.07 g (20.3 mmol) of triphenylsulfonium chloride, 100 mL of dichloromethane and 100 mL of water were added without isolating compound (b-2), and the mixture was stirred at room temperature for 10 hours. After separating the organic layer, washing with water was repeated 4 times. Purification by column chromatography gave 6.02 g (yield 43%) of a compound represented by the following formula (B-1) (hereinafter, also referred to as “compound (B-1)”).

[Synthesis Example 17] (Synthesis of compound (B-2))
3.00 g (4.16 mmol) of compound (B-1), 0.505 g (4.99 mmol) of triethylamine, 0.140 g (1.) of 1,4-diazabicyclo [2.2.2] octane in a 100 mL round bottom flask. 25 mmol) and 10 mL of acetonitrile were added, and stirring was started in a water bath. A solution prepared by dissolving 0.991 g (4.99 mmol) of adamantane carbonyl chloride in 10 mL of acetonitrile was slowly added dropwise thereto. After completion of the dropping, the mixture was stirred at room temperature for 2 hours and then at 50 ° C. for 8 hours. After adding dichloromethane, the mixture was washed 3 times with saturated aqueous sodium hydrogen carbonate solution and twice with saturated aqueous ammonium chloride solution. 2. The compound represented by the following formula (B-2) (hereinafter, also referred to as “compound (B-2)”) is obtained by drying with anhydrous sodium sulfate, distilling off the solvent, and then purifying by column chromatography. 53 g (yield 69%) was obtained.

[Synthesis Examples 18 to 29] (Synthesis of Compounds (B-3) to (B-14))
The precursors were appropriately selected, and the same operations as in Synthesis Example 1 were carried out to synthesize compounds represented by the following formulas (B-3) to (B-14).

<Preparation of radiation-sensitive resin composition>
The components other than the [A] polymer constituting the radiation-sensitive resin composition are shown.

[[C] Solvent]
C-1: Propylene glycol monomethyl ether acetate C-2: Cyclohexane C-3: γ-Butyrolactone

[[D] Other acid generators]
[D] As other acid generators, a [D1] acid generator composed of a sulfonium salt and a [D2] acid generator composed of a photodisintegrating base were used.
[[D1] Acid generator]
[D1] Compounds represented by the following formulas (D1-1) to (D1-9) were used as the acid generator.

[[D2] Acid generator]
[D2] Compounds represented by the following formulas (D2-1) to (D2-5) were used as the acid generator.

[[E] Nitrogen-containing compound]
[E] As the nitrogen-containing compound, compounds represented by the following formulas (E-1) to (E-4) were used.

[Example 1]
[A] 100 parts by mass of (A-1) as a polymer, 7 parts by mass of (B-1) as a [B] compound, 2,427 parts by mass of (C-1) as a [C] solvent, (C) -2) 1,040 parts by mass and (C-3) 200 parts by mass, [D] 10 parts by mass of (D-1) as another acid generator, and (F) polymer containing a fluorine atom ( F-1) A radiation-sensitive resin composition (J-1) was prepared by mixing 3 parts by mass and filtering with a 0.2 μm polymer filter.

[Examples 2 to 17 and Comparative Examples 1 to 17]
Radiation-sensitive resin compositions (J-2) to (J-17) and (CJ-1) to (CJ-1) to (CJ-1) to (CJ-1) to (CJ-1) to (CJ-1) to (CJ-1) to (CJ-1) to (CJ-1) to (CJ-1) to (CJ-1)- CJ-17) was prepared.

<Formation of resist pattern (1): ArF excimer laser immersion exposure, alkaline development>
A composition for forming an underlayer antireflection film (“ARC66” by Brewer Science) was applied to the surface of a 12-inch silicon wafer using a spin coater (“CLEN TRACK ACT12” by Tokyo Electron Limited), and then the temperature was 205 ° C. A lower antireflection film having a film thickness of 105 nm was formed by heating for 60 seconds. Each radiation-sensitive resin composition was applied onto the lower antireflection film using the spin coater, and PB was performed at 100 ° C. for 50 seconds. Then, it was cooled at 23 ° C. for 30 seconds to form a resist film having a film thickness of 90 nm. Next, this coating film was subjected to an ArF excimer laser immersion exposure apparatus (ASML's "TWINSCAN XT-1900i") under optical conditions of NA = 1.35 and Dipole35X (σ = 0.97 / 0.77). Was exposed through a mask pattern for forming a resist pattern of 38 nm line and space (1 L / 1S). After the exposure, PEB was performed at 90 ° C. for 50 seconds. Then, paddle development was carried out at 23 ° C. for 30 seconds using a 2.38 mass% TMAH aqueous solution. Next, a resist pattern of 38 nm line and space (1 L / 1S) was formed by rinsing with ultrapure water for 7 seconds and then spin-drying at 2,000 rpm for 15 seconds. At this time, the optimum exposure amount (Eop) was defined as the exposure amount at which the portion exposed through the mask pattern for pattern formation of 38 nm Line 100 nm Pitch forms a line having a line width of 38 nm.

<Formation of resist pattern (2): ArF excimer laser immersion exposure, organic solvent development>
The negative type resist pattern was operated in the same manner as in the above resist pattern formation (1) except that the organic solvent was developed using n-butyl acetate instead of the TMAH aqueous solution and the resist was not washed with water. Was formed.

<Evaluation>
Each of the radiation-sensitive resin compositions was evaluated by measuring the formed resist pattern according to the following method. The evaluation results are shown in Table 4 below. A scanning electron microscope (“CG-4100” manufactured by Hitachi High-Technologies Corporation) was used to measure the length of the resist pattern.

[LWR performance]
The resist pattern formed by irradiating the exposure amount of Eop obtained above was observed from the upper part of the pattern using the scanning electron microscope. A total of 500 points of variation in line width were measured, and a 3-sigma value was obtained from the distribution of the measured values, which was defined as LWR performance (nm). The smaller the value of the LWR performance, the smaller the rattling of the line and the better. The LWR performance can be evaluated as "good" when it is 2.5 nm or less, and as "bad" when it exceeds 2.5 nm.

[CDU (Critical Dimensions Uniformity) Performance]
The resist pattern formed by irradiating the exposure amount of Eop obtained above was observed from the upper part of the pattern using the scanning electron microscope. 20 points of line width are measured in the range of 400 nm to obtain the average value, the average value is measured at a total of 500 points at arbitrary points, 3 sigma values are obtained from the distribution of the measured values, and this is the CDU performance (nm). ). The smaller the value of the CDU performance, the smaller the variation in line width over a long period and the better. The CDU performance can be evaluated as "good" when it is 1.5 nm or less, and as "bad" when it exceeds 2.0 nm.

[EL (Focus margin: Exposure latitude) performance]
The EL performance of the radiation-sensitive resin composition was evaluated by each value of 10% EL, Bridge limit and Collapse limit measured by the following method.

(10% EL)
The range of the exposure amount when the size of the resist pattern resolved when the mask pattern for forming the resist pattern of 38 nm line and space (1L / 1S) is within ± 10% of the design size of the mask. The ratio to the above Eop was 10% EL (%). The larger the value of 10% EL, the smaller and better the amount of change in patterning performance with respect to the change in exposure amount.

(Bridge limit)
In the formation of the resist pattern, the minimum pattern width at which bridges occur when the exposure amount is reduced in the case of alkaline development from the above Eop and when the exposure amount is increased in the case of organic solvent development ( The Exposure limit) (nm) was determined, and this value was used as an index of the Exposure limit. The larger the value of the Bridge limit, the less likely it is that bridge defects will occur, and the better.

(Collapse limit)
In the formation of the resist pattern, the minimum pattern width at which pattern collapse occurs when the exposure amount is increased in the case of alkaline development from the above Eop and when the exposure amount is decreased in the case of organic solvent development ( The Collapse limit) (nm) was determined, and this value was used as an index of the Collapse limit. The smaller the Collapse limit value, the less likely it is that the resist pattern will collapse, and the better.

[Development defect suppression]
A coating film is formed with a radiation-sensitive resin composition on a 12-inch silicon wafer on which a lower layer antireflection film is formed by a composition for forming a lower layer antireflection film (“ARC66” of Nissan Chemical Industries, Ltd.), and the temperature is 120 ° C. for 50 seconds. SB (SoftBake) was performed to form a resist film having a film thickness of 110 nm. Next, for this resist film, using an ArF excimer laser immersion exposure device (NIKON's "NSR-S610C"), the target size is 38 nm in width under the conditions of NA = 1.3, ratio = 0.800, and Dipole. The exposure was made through a mask pattern for forming a line and space (1L / 1S). After the exposure, PEB was performed at 95 ° C. for 50 seconds. Then, it was developed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution or butyl acetate for 10 seconds by a GP nozzle of a developing device (“Clean Track ACT8” manufactured by Tokyo Electron Limited). In the case of developing with an aqueous solution of tetramethylammonium hydroxide, the mixture was subsequently rinsed with pure water for 15 seconds and spin-dried at 2,000 rpm. At this time, the exposure amount forming 1L / 1S having a width of 38 nm was set as the optimum exposure amount. With this optimum exposure amount, 1 L / 1S having a line width of 38 nm was formed on the entire surface of the wafer to prepare a wafer for defect inspection. A scanning electron microscope (Hitachi High-Technologies Corporation, CC-4000) was used for length measurement. The number of defects on the defect inspection wafer was measured using a defect inspection apparatus (“KLA2810” manufactured by KLA-Tencor). Then, the measured defects were classified into those judged to be defects derived from the resist film and foreign substances derived from the outside, and the number of those judged to be defects derived from the resist film was calculated. The development defect inhibitory property is better as the number of defects determined to be derived from the resist film is smaller.

[Membrane contraction inhibitory after PEB]
A composition for forming an underlayer antireflection film (ARC66, manufactured by Brewer Science) is applied to the surface of a 12-inch silicon wafer using a spin coater (CLEAN TRACK AT12, manufactured by Tokyo Electron), and then heated at 205 ° C. for 60 seconds. By doing so, a lower antireflection film having a film thickness of 105 nm was formed. Each of the above-prepared radiation-sensitive resin compositions was applied onto the lower antireflection film using the spin coater, and PB was performed at 90 ° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 seconds to form a resist film with a film thickness of 90 nm. Next, this resist film was exposed to the entire surface at 70 mJ using an ArF excimer laser immersion exposure apparatus (NSR-S610C, manufactured by NIKON), and then the film thickness was measured to determine the film thickness A. Subsequently, after performing PEB at 90 ° C. for 60 seconds, the film thickness was measured again to determine the film thickness B. At this time, 100 × (AB) / A (%) was determined, and this was used as the membrane contraction rate after PEB. The smaller the measured value, the better the film shrinkage inhibitory property after PEB.

[Example 18]
[A] 100 parts by mass of (A-1) as a polymer, 3.6 parts by mass of (B-1) as a [B] compound, 4280 parts by mass of (C-1) as a [C] solvent, (C) -2) 1830 parts by mass and [D] 20 parts by mass of (D-1) as another acid generator were mixed and filtered through a 0.2 μm polymer filter to obtain a radiation-sensitive resin composition (J-). 21) was prepared.

[Examples 19 to 22 and Comparative Examples 18 to 22]
Radiation-sensitive resin compositions (J-18) to (J-22) and (CJ-18) to (CJ-18) to (CJ-18) to (CJ-18) to (CJ-18) to (CJ-18) to (CJ-18) to (CJ-18) to (CJ-18) to (CJ-18) to (CJ-18) CJ-22) was prepared.

<Formation of resist pattern (3): electron beam exposure, alkaline development>
Each of the radiation-sensitive resin compositions shown in Table 5 above was applied to the surface of an 8-inch silicon wafer using a spin coater (CLEAN TRACK ACT8, manufactured by Tokyo Electron), and PB was performed at 90 ° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 seconds to form a resist film with a film thickness of 50 nm. Next, this resist film was irradiated with an electron beam using a simple electron beam drawing apparatus (manufactured by Hitachi, Ltd., model "HL800D", output: 50 KeV, current density: 5.0 A / cm ² ). After irradiation, PEB was performed at 120 ° C. for 60 seconds. Then, it was developed 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.

<Formation of resist pattern (4): electron beam exposure, organic solvent development>
The negative type resist pattern was operated in the same manner as in the above resist pattern formation (1) except that the organic solvent was developed using n-butyl acetate instead of the TMAH aqueous solution and the resist was not washed with water. Was formed.

<Evaluation>
The resist pattern formed by using each of the above-mentioned radiation-sensitive resin compositions was evaluated in the same manner as in the above-mentioned Examples. The results are shown in Table 6 below.

From the results in Tables 3 and 6, the radiation-sensitive resin composition has LWR performance, CDU performance, EL performance and development defect suppression in both alkaline development and organic solvent development in ArF exposure and electron beam exposure. It was shown to be excellent in sex. In addition, the results in Table 4 also showed that the ArF exposure was excellent in suppressing film shrinkage after PEB. On the other hand, it was shown that the radiation-sensitive resin compositions of Comparative Examples were inferior to those of Examples in the above-mentioned performance.

According to the radiation-sensitive resin composition and the resist pattern forming method of the present invention, a resist pattern having excellent LWR performance, CDU performance, EL performance, development defect suppressing property and film shrinkage suppressing property after PEB can be formed. The compound of the present invention can be suitably used as a component of the radiation-sensitive resin composition. Therefore, these can be suitably used for pattern formation in semiconductor device manufacturing and the like, which are expected to be further miniaturized in the future.

Claims (30)

A polymer having a first structural unit containing an acid dissociative group and
Compounds represented by the following formula (1) and
A radiation-sensitive resin composition containing a solvent.

(In the formula ^{(1), R 1, R} 2, R 3 and ^{R 4} are each independently .R ⁵ and a monovalent organic group containing no hydrogen atom or a fluorine atom having 1 to 20 carbon atoms R ⁶ is an independently hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ⁷ is an n-valent chain hydrocarbon group containing a fluorine atom having 1 to 10 carbon atoms. . R ¹ and R ² , R ¹ and R ³ , R ¹ and R ⁵ , R ³ and R ⁴ , R ³ and R ⁵ or R ⁵ and R ⁶ are combined together with carbon atoms to which they are bonded. It may represent an alicyclic structure having 3 to 20 ring members. X ⁺ is a monovalent radiosensitive onium cation. Y ⁻ is SO ₃ ⁻ or COO ⁻ . N is 1 or 2. When n is 2, R ¹ of ² may be the same or different, R ² of ² may be the same or different, and R ³ of 2 may be the same or different. R ⁴ may be the same or different, R ⁵ of 2 may be the same or different, R ⁶ of 2 may be the same or different, and X ⁺ of 2 may be the same or different. The Y ⁻ of 2 may be the same or different.) The radiation-sensitive resin composition according to claim 1 , wherein R ³ in the above formula (1) is −OR ⁸ and R ⁸ is a monovalent organic group containing no hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. Stuff. The radiation-sensitive resin composition according to claim 1 or 2 , wherein R ⁵ in the above formula (1) is −OR ⁹ and R ⁹ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. .. Claim 1, claim 2 or claim 3 in which R ¹ in the above formula (1) is −OR ¹⁰ and R ¹⁰ is a monovalent organic group containing no hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. The radiation-sensitive resin composition according to. The radiation-sensitive resin composition according to claim 1, claim 2 or claim 3 , wherein R ¹ and R ² in the above formula (1) are hydrogen atoms. A polymer having a first structural unit containing an acid dissociative group and
Compounds represented by the following formula (1) and
With solvent
Radiation-sensitive resin composition containing.

(In equation (1), R ¹ , R ² And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ³ Is -OR ⁸ Is. R ⁸ Is a monovalent organic group that does not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ¹ And R ⁵ , R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A polymer having a first structural unit containing an acid dissociative group and
Compounds represented by the following formula (1) and
With solvent
Radiation-sensitive resin composition containing.

(In equation (1), R ¹ , R ² , R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ Is -OR ⁹ Is. R ⁹ Is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ¹ And R ⁵ , R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A polymer having a first structural unit containing an acid dissociative group and
Compounds represented by the following formula (1) and
With solvent
Radiation-sensitive resin composition containing.

(In equation (1), R ¹ Is -OR ¹⁰ Is. R ¹⁰ Is a monovalent organic group that does not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ² , R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ¹ And R ⁵ , R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A polymer having a first structural unit containing an acid dissociative group and
Compounds represented by the following formula (1) and
With solvent
Radiation-sensitive resin composition containing.

(In equation (1), R ¹ And R ² Is a hydrogen atom. R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A polymer having a first structural unit containing an acid dissociative group and
Compounds represented by the following formula (1) and
With solvent
Radiation-sensitive resin composition containing.

(In equation (1), R ¹ , R ² , R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Is a hydrogen atom. R ⁷ Is a fluorinated hydrocarbon group having 1 to 10 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ³ And R ⁴ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) The radiation-sensitive resin composition according to any one of claims 1 to 10, wherein the first structural unit is represented by the following formula (2).

(In the formula (2), R ^A1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^A2 is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ^A3 and R. ^A4 is a monovalent hydrocarbon group having 1 to 20 carbon atoms independently, or has a ring structure having 3 to 20 ring members formed by combining these groups with carbon atoms to which they are bonded. Represent.) The step of applying the radiation-sensitive resin composition according to any one of claims 1 to 11 on one surface side of the substrate, and
The process of exposing the resist film obtained by the above coating and
A resist pattern forming method comprising the step of developing the exposed resist film. A radiation-sensitive acid generator represented by the following formula (1).

(In the formula ^{(1), R 1, R} 2, R 3 and ^{R 4} are each independently .R ⁵ and a monovalent organic group containing no hydrogen atom or a fluorine atom having 1 to 20 carbon atoms R ⁶ is an independently hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ⁷ is an n-valent chain hydrocarbon group containing a fluorine atom having 1 to 10 carbon atoms. . R ¹ and R ² , R ¹ and R ³ , R ¹ and R ⁵ , R ³ and R ⁴ , R ³ and R ⁵ or R ⁵ and R ⁶ are combined together with carbon atoms to which they are bonded. It may represent an alicyclic structure having 3 to 20 ring members. X ⁺ is a monovalent radiosensitive onium cation. Y ⁻ is SO ₃ ⁻ or COO ⁻ . N is 1 or 2. When n is 2, R ¹ of ² may be the same or different, R ² of ² may be the same or different, and R ³ of 2 may be the same or different. R ⁴ may be the same or different, R ⁵ of 2 may be the same or different, R ⁶ of 2 may be the same or different, and X ⁺ of 2 may be the same or different. The Y ⁻ of 2 may be the same or different.) A radiation-sensitive acid generator represented by the following formula (1).

(In equation (1), R ¹ , R ² And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ³ Is -OR ⁸ Is. R ⁸ Is a monovalent organic group that does not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ¹ And R ⁵ , R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A radiation-sensitive acid generator represented by the following formula (1).

(In equation (1), R ¹ , R ² , R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ Is -OR ⁹ Is. R ⁹ Is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ¹ And R ⁵ , R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A radiation-sensitive acid generator represented by the following formula (1).

(In equation (1), R ¹ Is -OR ¹⁰ Is. R ¹⁰ Is a monovalent organic group that does not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ² , R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ¹ And R ⁵ , R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A radiation-sensitive acid generator represented by the following formula (1).

(In equation (1), R ¹ And R ² Is a hydrogen atom. R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A radiation-sensitive acid generator represented by the following formula (1).

(In equation (1), R ¹ , R ² , R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Is a hydrogen atom. R ⁷ Is a fluorinated hydrocarbon group having 1 to 10 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ³ And R ⁴ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A compound represented by the following formula (1).

(In the formula ^{(1), R 1, R} 2, R 3 and ^{R 4} are each independently .R ⁵ and a monovalent organic group containing no hydrogen atom or a fluorine atom having 1 to 20 carbon atoms R ⁶ is an independently hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ⁷ is an n-valent chain hydrocarbon group containing a fluorine atom having 1 to 10 carbon atoms. . R ¹ and R ² , R ¹ and R ³ , R ¹ and R ⁵ , R ³ and R ⁴ , R ³ and R ⁵ or R ⁵ and R ⁶ are combined together with carbon atoms to which they are bonded. It may represent an alicyclic structure having 3 to 20 ring members. X ⁺ is a monovalent radiosensitive onium cation. Y ⁻ is SO ₃ ⁻ or COO ⁻ . N is 1 or 2. When n is 2, R ¹ of ² may be the same or different, R ² of ² may be the same or different, and R ³ of 2 may be the same or different. R ⁴ may be the same or different, R ⁵ of 2 may be the same or different, R ⁶ of 2 may be the same or different, and X ⁺ of 2 may be the same or different. The Y ⁻ of 2 may be the same or different.) A compound represented by the following formula (1).

(In equation (1), R ¹ , R ² And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ³ Is -OR ⁸ Is. R ⁸ Is a monovalent organic group that does not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ¹ And R ⁵ , R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A compound represented by the following formula (1).

(In equation (1), R ¹ , R ² , R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ Is -OR ⁹ Is. R ⁹ Is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ¹ And R ⁵ , R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A compound represented by the following formula (1).

(In equation (1), R ¹ Is -OR ¹⁰ Is. R ¹⁰ Is a monovalent organic group that does not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ² , R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ¹ And R ⁵ , R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A compound represented by the following formula (1).

(In equation (1), R ¹ And R ² Is a hydrogen atom. R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A compound represented by the following formula (1).

(In equation (1), R ¹ , R ² , R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Is a hydrogen atom. R ⁷ Is a fluorinated hydrocarbon group having 1 to 10 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ³ And R ⁴ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. ) A compound represented by the following formula (i).

(In the formula ^{(i), R 1, R} 2, R 3 and ^{R 4} are each independently .R ⁵ and a monovalent organic group containing no hydrogen atom or a fluorine atom having 1 to 20 carbon atoms R ⁶ is an independently hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ⁷ is an n-valent chain hydrocarbon group containing a fluorine atom having 1 to 10 carbon atoms. R ¹ and R ² , R ¹ and R ³ , R ¹ and R ⁵ , R ³ and R ⁴ , R ³ and R ⁵ or R ⁵ and R ⁶ are composed of carbon atoms that are combined with each other and bonded to each other. It may represent an alicyclic structure having 3 to 20 ring members. Y ⁻ is SO ₃ ⁻ or COO ⁻ . N is 1 or 2. When n is 2, R ¹ of 2 is the same. But R ² of ² may be the same or different, R ³ of 2 may be the same or different, R ⁴ of 2 may be the same or different, R ^{5 of} 2. May be the same or different, R ⁶ of 2 may be the same or different, Y ⁻ of 2 may be the same or different. M is an a-valent metal cation. A is 1 Or 2. h is 1 or 2. However, it is assumed that a × h = n is satisfied.) A compound represented by the following formula (i).

(In equation (1), R ¹ , R ² And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ³ Is -OR ⁸ Is. R ⁸ Is a monovalent organic group that does not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ¹ And R ⁵ , R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. M is an a-valent metal cation. a is 1 or 2. h is 1 or 2. However, it is assumed that a × h = n is satisfied. ) A compound represented by the following formula (i).

(In equation (1), R ¹ , R ² , R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ Is -OR ⁹ Is. R ⁹ Is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ¹ And R ⁵ , R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. M is an a-valent metal cation. a is 1 or 2. h is 1 or 2. However, it is assumed that a × h = n is satisfied. ) A compound represented by the following formula (i).

(In equation (1), R ¹ Is -OR ¹⁰ Is. R ¹⁰ Is a monovalent organic group that does not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ² , R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ¹ And R ⁵ , R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. M is an a-valent metal cation. a is 1 or 2. h is 1 or 2. However, it is assumed that a × h = n is satisfied. ) A compound represented by the following formula (i).

(In equation (1), R ¹ And R ² Is a hydrogen atom. R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Are independently hydrogen atoms or monovalent organic groups having 1 to 20 carbon atoms. R ⁷ Is an n-valent organic group containing a fluorine atom having 1 to 20 carbon atoms. R ³ And R ⁴ , R ³ And R ⁵ Or R ⁵ And R ⁶ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ³ May be the same or different, 2 R ⁴ May be the same or different, 2 R ⁵ May be the same or different, 2 R ⁶ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. M is an a-valent metal cation. a is 1 or 2. h is 1 or 2. However, it is assumed that a × h = n is satisfied. ) A compound represented by the following formula (i).

(In equation (1), R ¹ , R ² , R ³ And R ⁴ Are independently monovalent organic groups that do not contain a hydrogen atom or a fluorine atom having 1 to 20 carbon atoms. R ⁵ And R ⁶ Is a hydrogen atom. R ⁷ Is a fluorinated hydrocarbon group having 1 to 10 carbon atoms. R ¹ And R ² , R ¹ And R ³ , R ³ And R ⁴ May represent an alicyclic structure having 3 to 20 ring members that is combined with each other and composed of carbon atoms to which they are bonded. X ^＋ Is a monovalent radiation-sensitive onium cation. Y ⁻ Is SO ₃ ⁻ Or COO ⁻ Is. n is 1 or 2. When n is 2, R of 2 ¹ May be the same or different, 2 R ² May be the same or different, 2 R ³ May be the same or different, 2 R ⁴ May be the same or different, 2 X ^＋ May be the same or different, 2 Y ⁻ May be the same or different. M is an a-valent metal cation. a is 1 or 2. h is 1 or 2. However, it is assumed that a × h = n is satisfied. )