JP2015148692A - Radiation-sensitive resin composition, resist pattern forming method, radiation-sensitive acid generator, and compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition which is excellent in LWR performance, resolution, rectangularity of a cross-sectional shape, and depth of focus.SOLUTION: The radiation-sensitive resin composition of the present invention contains a polymer having a first structural unit containing an acid-dissociable group, and a first radiation-sensitive acid generator. The first radiation-sensitive acid generator comprises a compound represented by formula (1). In the formula (1), Rand Rare each independently a hydrogen atom, a fluorine atom, a 1-20C monovalent hydrocarbon group, or a 1-20C monovalent fluorinated hydrocarbon group, provided that at least one of Rand Ris a fluorine atom or a fluorinated hydrocarbon group.

Description

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

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

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

  Under such circumstances, recently, it is required to form a resist pattern having a line width of 50 nm or less. The demand for the above-mentioned resolution and the rectangular shape of the cross-sectional shape is further increased, and a high-precision pattern can be obtained by being excellent in LWR (Line Width Roughness) performance indicating the variation in the line width of the resist pattern, and further excellent in the depth of focus. There is also a need to improve process stability. However, the above conventional radiation-sensitive resin composition cannot satisfy these requirements.

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

  The present invention has been made on the basis of the above-mentioned circumstances, and its purpose is a feeling that it is excellent in LWR performance, resolution, rectangularity of a cross-sectional shape and depth of focus (hereinafter also referred to as “LWR performance etc.”). It is to provide a radiation resin composition.

（式（１）中、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立して炭素数１〜２０の鎖状炭化水素基若しくは炭素数３〜２０の１価の脂環式炭化水素基であるか、又はこれらの基のうちの２つ以上が互いに合わせられこれらが結合する炭素原子と共に構成される環員数３〜２０の環構造を表す。Ｒ^４及びＲ^５は、それぞれ独立して、水素原子、フッ素原子、炭素数１〜２０の１価の炭化水素基又は炭素数１〜２０の１価のフッ素化炭化水素基である。ｍは、１〜３の整数である。ｍが２以上の場合、複数のＲ^４は同一でも異なっていてもよく、複数のＲ^５は同一でも異なっていてもよい。但し、Ｒ^４及びＲ^５のうちの少なくともいずれかはフッ素原子又はフッ素化炭化水素基である。Ｒ^６及びＲ^７は、それぞれ独立して、水素原子又は炭素数１〜２０の１価の炭化水素基である。ｎは、１又は２である。ｎが２の場合、複数のＲ^６は同一でも異なっていてもよく、複数のＲ^７は同一でも異なっていてもよい。Ａは、−Ｏ−又は−ＮＲ^８−である。Ｒ^８は、水素原子又は炭素数１〜１０の１価の炭化水素基である。Ｍ^＋は、１価の感放射線性オニウムカチオンである。） The invention made to solve the above problems is
Polymer having first structural unit (hereinafter also referred to as “structural unit (I)”) containing an acid dissociable group (hereinafter also referred to as “[A] polymer”), and first radiation-sensitive acid generator (Hereinafter also referred to as “[B] acid generator”), and the first radiation-sensitive acid generator is a radiation-sensitive resin composition comprising a compound represented by the following formula (1).

(In the formula (1), R ¹ , R ² and R ³ are each independently a chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. Or a ring structure having 3 to 20 ring members constituted by carbon atoms to which two or more of these groups are combined with each other and bonded to each other, and R ⁴ and R ⁵ are each independently hydrogen An atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, m is an integer of 1 to 3. m is 2 or more. In this case, a plurality of R ⁴ may be the same or different, and a plurality of R ⁵ may be the same or different, provided that at least one of R ⁴ and R ⁵ is a fluorine atom or a fluorinated hydrocarbon. is a group .R ⁶ and R ⁷ are each independently hydrogen atom or a carbon atoms Is a monovalent hydrocarbon group having to 20 .n, when is 1 or 2 .n is 2, a plurality of R ⁶ may be the same or different, a plurality of R ⁷ is either the same or different A is —O— or —NR ⁸ —, R ⁸ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and M ⁺ is a monovalent radiation-sensitive onium. Cation.)

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

Yet another invention made to solve the above problems is as follows:
It is a radiation sensitive acid generator which consists of a compound represented by the said Formula (1).

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

Here, the “organic group” refers to a group containing at least one carbon atom.
The “hydrocarbon group” includes a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The “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 include a cyclic structure but includes only a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. The term “alicyclic hydrocarbon group” refers to a hydrocarbon group that includes only an alicyclic structure as a ring structure and does not include an aromatic ring structure, and includes a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Includes both hydrocarbon groups. However, it is not necessary to be composed only of the alicyclic structure, and a part thereof may include a chain structure. “Aromatic hydrocarbon group” refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it is not necessary to be composed only of an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic structure.

  According to the radiation sensitive resin composition and the resist pattern forming method of the present invention, it is possible to form a resist pattern having excellent LWR performance, resolution, and cross-sectional rectangularity while exhibiting excellent depth of focus. The radiation sensitive acid generator of this invention can be used suitably as a component of the said radiation sensitive resin composition. The compound of the present invention can be suitably used as the radiation sensitive acid generator. Therefore, these can be suitably used for manufacturing processes of semiconductor devices, which are expected to be further miniaturized in the future.

<Radiation sensitive resin composition>
The radiation sensitive resin composition contains a [A] polymer and a [B] acid generator. In addition, the radiation-sensitive resin composition includes, as a suitable component, a second radiation-sensitive acid generator (hereinafter referred to as “[C1] and others”) that generates an acid stronger than the acid generated from the first radiation-sensitive acid generator. And [D] nitrogen atom-containing compound (hereinafter also referred to as “[D] compound”), [E] fluorine atom-containing polymer (hereinafter also referred to as “[E] polymer”). And [F] may contain a solvent, and may contain other optional components as long as the effects of the present invention are not impaired. Hereinafter, each component will be described.

<[A] polymer>
[A] The polymer is a polymer having the structural unit (I). According to the radiation-sensitive resin composition, the acid-dissociable group of the [A] polymer in the exposed area is dissociated by the acid generated from the [B] acid generator, [C] other acid generator, etc. upon irradiation with radiation. Thus, there is a difference in solubility in the developer between the exposed portion and the unexposed portion, and as a result, a resist pattern can be formed. The “acid-dissociable group” refers to a group that replaces a hydrogen atom such as a carboxy group or a hydroxy group and dissociates by the action of an acid. [A] The polymer is at least selected from the group consisting of a structural unit represented by the following formula (5-1) and a structural unit represented by (5-2) in addition to the structural unit (I). One type (hereinafter also referred to as “structural unit (II)”), a structural unit represented by the following formula (4) (hereinafter also referred to as “structural unit (III)”), and the structural unit (I) to You may have other structural units other than (III). [A] The polymer may have one or more of each structural unit. Hereinafter, each structural unit will be described.

[Structural unit (I)]
The structural unit (I) is a structural unit containing an acid dissociable group. The structural unit (I) is preferably a structural unit represented by the following formula (3).

In said formula (3), R < ¹² > is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ¹³ is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ¹⁴ and R ¹⁵ are each independently a chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or these groups are combined with each other. The C3-C20 alicyclic structure comprised with the carbon atom which these couple | bond together is represented.

R ¹² is preferably a hydrogen atom or a methyl group, and more preferably a methyl group, from the viewpoint of the copolymerizability of the monomer that gives the structural unit (I).

Examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms represented by R ¹³ include a monovalent chain hydrocarbon group having 1 to 10 carbon atoms and a monovalent alicyclic ring having 3 to 10 carbon atoms. And a monovalent aromatic hydrocarbon group having 6 to 10 carbon atoms.

Examples of the monovalent chain hydrocarbon group having 1 to 10 carbon atoms represented by R ¹³ , R ¹⁴ and R ¹⁵ include, for example,
Alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl and n-pentyl;
Alkenyl groups such as ethenyl group, propenyl group, butenyl group, pentenyl group;
Examples include alkynyl groups such as ethynyl group, propynyl group, butynyl group, and pentynyl group.
Among these, an alkyl group is preferable, an alkyl group having 1 to 4 carbon atoms is preferable, a methyl group, an ethyl group, and an i-propyl group are more preferable, and an ethyl group is particularly preferable.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by the above R ¹³ , R ¹⁴ and R ¹⁵ include:
A monocyclic cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group;
A polycyclic cycloalkyl group such as a norbornyl group, an adamantyl group, a tricyclodecyl group, a tetracyclododecyl group;
A monocyclic cycloalkenyl group such as a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, a cyclohexenyl group;
And polycyclic cycloalkenyl groups such as a norbornenyl group and a tricyclodecenyl group.
Among these, a monocyclic cycloalkyl group and a polycyclic cycloalkyl group are preferable, and a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group are more preferable.

Examples of the monovalent aromatic hydrocarbon group having 6 to 10 carbon atoms represented by R ¹³ include:
Aryl groups such as phenyl group, tolyl group, xylyl group, mesityl group;
Examples include aralkyl groups such as benzyl group and phenethyl group.

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

The structural unit represented by the above formula (3) is a carbon atom in which R ¹³ is a monovalent chain hydrocarbon group having 1 to 10 carbon atoms, and R ¹⁴ and R ¹⁵ are combined with each other. R ¹³ is a monovalent alicyclic hydrocarbon group having 3 to 10 carbon atoms, and R ¹⁴ and R ¹⁵ are 1 to 10 carbon atoms. A monovalent chain hydrocarbon group, wherein R ¹³ is an alkyl group having 1 to 10 carbon atoms, and R ¹⁴ and R ¹⁵ are combined with each other to form a ring composed of carbon atoms to which they are bonded. More preferably, it represents a cycloalkane structure having 3 to 20 members, R ¹³ is a cycloalkyl group having 3 to 10 carbon atoms, and R ¹⁴ and R ¹⁵ are alkyl groups having 1 to 10 carbon atoms. ¹³ is alkyl having 1 to 4 carbon atoms A monocyclic cycloalkane structure having 5 to 8 ring members or a polycyclic cycloalkane structure having 7 to 12 ring members constituted by R ¹⁴ and R ¹⁵ together with the carbon atom to which they are bonded. Those represented are more preferable, and a 1-ethyl-1-cyclopentyl group, a 2-ethyl-2-adamantyl group, a 2-methyl-2-adamantyl group, and a 2-adamantyl-2-propyl group are particularly preferable.

  Examples of the structural unit (I) include structural units represented by the following formulas (3-1) to (3-8).

R < ¹² > -R < ¹⁵ > is synonymous with the said Formula (3) in said formula (3-1)-(3-8). Each r is independently an integer of 1 to 3.

  As said r, 1 or 2 is preferable and 1 is more preferable.

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

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

[Structural unit (II)]
The structural unit (II) includes a structural unit represented by the following formula (5-1) (hereinafter also referred to as “structural unit (II-1)”) and a structural unit represented by the following formula (5-2) ( Hereinafter, it is at least one selected from the group consisting of “structural unit (II-2)”. When the [A] polymer has the structural unit (II), the [B] acid generator can improve the dispersibility in the [A] polymer. Moreover, the adhesiveness to the board | substrate of the resist pattern formed from the said radiation sensitive resin composition can be improved. As a result, the LWR performance and the like of the radiation sensitive resin composition can be further improved.

In the formula ^{(5-1), R 18} is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. E ¹ is a single bond, —CO—O—, —CO—NH—, or —CO—O— (CH ₂ ) _i —CO—O—. i is an integer of 1-6. R ¹⁹ is a non-acid-dissociable group containing a polar group.
In said formula (5-2), R18 ^' is a hydrogen atom or a methyl group. R ^a and R ^b are each independently a hydrogen atom, a fluorine atom, a hydroxy group, or a monovalent organic group. s is an integer of 1 to 3. When s is 2 or more, the plurality of R ^a and R ^b may be the same or different. R ^19a and R ^19b are each independently a hydrogen atom, a fluorine atom, a hydroxy group, or a monovalent organic group.

In the structural unit (II-1),
R ¹⁸ is preferably a hydrogen atom or a methyl group, and more preferably a methyl group, from the viewpoint of the copolymerizability of the monomer that provides the structural unit (II-1).

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

Examples of the polar group in the non-acid dissociable group represented by R ¹⁹ that includes a polar group include monovalent groups such as a hydroxy group, a carboxy group, a cyano group, a sulfo group, a mercapto group, and an amino group ( a); a carbonyl group, —O—, —S—, —NR′—, a divalent group (b) formed by combining these, and the like. R ′ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms.

Examples of the group containing a non-acid dissociable and polar group represented by R ¹⁹ include, for example, a part or all of the hydrogen atoms of a monovalent hydrocarbon group having 1 to 20 carbon atoms as the monovalent group ( a group substituted with a), a group containing the divalent group (b) between some or all of the carbon-carbons of a monovalent hydrocarbon group having 1 to 20 carbon atoms, monovalent having 1 to 20 carbon atoms A part or all of the hydrogen atoms of the hydrocarbon group is substituted with the monovalent group (a), and a group containing the divalent group (b) between some or all of the carbon-carbons. Can be mentioned.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and carbon. Examples thereof include monovalent aromatic hydrocarbon groups of several 6 to 20.
Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include:
Alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl and n-pentyl;
Alkenyl groups such as ethenyl group, propenyl group, butenyl group, pentenyl group;
Examples include alkynyl groups such as ethynyl group, propynyl group, butynyl group, and pentynyl group.
As said C3-C20 monovalent alicyclic hydrocarbon group, the group similar to what was illustrated as R <^13> , R <^14> and R < ¹⁵ > in said Formula (3), etc. are mentioned, for example.
Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include:
Aryl groups such as phenyl, tolyl, xylyl, mesityl, naphthyl, methylnaphthyl, anthryl, methylanthryl;
Examples include aralkyl groups such as benzyl group, phenethyl group, naphthylmethyl group, and anthrylmethyl group.

Examples of R ¹⁹ include a group having a lactone structure, a group having a cyclic carbonate structure, a group having a sultone structure, and a group having a hydroxy group.

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

In the structural unit (II-2),
R ^{18 ′} is preferably a hydrogen atom from the viewpoint of the copolymerizability of the monomer giving the structural unit (II-2).

Examples of the monovalent organic group represented by R ^a , R ^b , R ^19a and R ^19b include, for example, a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and a monovalent chain group having 3 to 20 carbon atoms. An alicyclic hydrocarbon group, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a group in which some or all of the hydrogen atoms of these groups are substituted with a substituent, and the carbon-carbon gap of these groups And —CO—, —CS—, —O—, —S— or —NR ″ — or a group containing a combination of two or more thereof. R ″ represents a hydrogen atom or 1 Valent organic group.

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

As the structural unit (II), for example,
Structural units represented by the following formulas (5-1-1) to (5-1-14) as the structural unit (II-1);
Examples of the structural unit (II-2) include a structural unit represented by the following formula (5-2-1) and a structural unit represented by (5-2-2).

In the formulas (5-1-1) to (5-1-14), R ¹⁸ has the same meaning as the formula (5-1).
In the formulas (5-2-1) and (5-2-2), R ^{18 ′} has the same meaning as the formula (5-2).

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

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

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

In the formula ^{(4), R 16} is a hydrogen atom or a methyl group. R ¹⁷ is a monovalent organic group having 1 to 20 carbon atoms. p is an integer of 0-3. When p is 2 or 3, a plurality of R ¹⁷ may be the same or different. q is an integer of 1 to 3. However, p + q is 5 or less.

R ¹⁶ is preferably a hydrogen atom from the viewpoint of copolymerizability of the monomer that gives the structural unit (III).

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ¹⁷ include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and a monovalent alicyclic group having 3 to 20 carbon atoms. A hydrocarbon group, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, a group in which part or all of the hydrogen atoms of these groups are substituted with a substituent, and between these carbon-carbon groups, CO—, —CS—, —O—, —S— or —NR ″ — or a group containing a combination of two or more of these, and the like. R ″ represents a hydrogen atom or a monovalent organic group. It is a group.
Among these, a monovalent chain hydrocarbon group is preferable, an alkyl group is more preferable, and a methyl group is more preferable.

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

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

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

In the above formulas (4-1) to (4-4), R ¹⁶ has the same meaning as the above formula (4).

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

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

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

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

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

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

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

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

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

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

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

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

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

<[B] Acid generator>
[B] The acid generator is composed of a compound represented by the following formula (1) (hereinafter also referred to as “compound (1)”). The said radiation sensitive resin composition is excellent in LWR performance etc. by containing a [B] acid generator in addition to a [A] polymer.

In the formula ^(1), R 1, ^{R 2} and ^{R 3} are each independently is a monovalent alicyclic hydrocarbon group having a chain hydrocarbon group or a 3 to 20 carbon atoms having 1 to 20 carbon atoms Or a ring structure having 3 to 20 ring members constituted by two or more of these groups being combined with each other and the carbon atom to which they are bonded. R ⁴ and R ⁵ are each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. m is an integer of 1-3. When m is 2 or more, the plurality of R ⁴ may be the same or different, and the plurality of R ⁵ may be the same or different. However, at least one of R ⁴ and R ⁵ is a fluorine atom or a fluorinated hydrocarbon group. R ⁶ and R ⁷ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. n is 1 or 2. When n is 2, the plurality of R ⁶ may be the same or different, and the plurality of R ⁷ may be the same or different. A is —O— or —NR ⁸ —. R ⁸ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. M ⁺ is a monovalent radiation-sensitive onium cation. )

[B] The acid generator, _-SO ³ in the formula (1) - ^{M +} is, by changing to -SO ₃ H in the exposed area, resulting in sulfonic acids.
The radiation sensitive resin composition is, for example, an acid generator that generates an acid stronger than the acid generated from the [B] acid generator (hereinafter referred to as “[C1] Other acid generators” in addition to the [B] acid generator. [B] acid generator exhibits a function of capturing acid generated from [C1] other acid generators, etc. in the unexposed area.
In addition to the [B] acid generator, for example, the radiation sensitive resin composition generates an acid generator that generates a weaker acid than the acid generated from the [B] acid generator (hereinafter referred to as “[C2] other [B] The acid generator exhibits a function of generating an acid having an action of dissociating the acid-dissociable group of the polymer [A] in the exposed portion. .

The reason why the radiation-sensitive resin composition exhibits the above-described effect by containing the [B] acid generator is not necessarily clear, but can be inferred as follows, for example. That is, the [B] acid generator has a fluorine atom or a fluorinated hydrocarbon group bonded at a position relatively distant from SO ₃ ⁻ , so that the acid strength of SO ₃ H or SO ₃ ⁻ M ⁺ The basic strength can be adjusted to an appropriate level. Moreover, since the [B] acid generator contains -A-CO- and has an appropriate polarity, the dispersibility in the [A] polymer can be improved. Further, due to this moderate polarity, the diffusion of the acid generated from the [B] acid generator is moderately shortened. As a result, the LWR performance and the like of the radiation sensitive resin composition can be improved. [B] The acid generators may be used alone or in combination of two or more.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^{4 to} R ⁸ include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms and a monovalent hydrocarbon group having 3 to 20 carbon atoms. Alicyclic hydrocarbon groups, monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms, and the like.

The chain hydrocarbon group having 1 to 20 carbon atoms represented by ^R 1 to R ^8, for example, the formula similar group as those exemplified as ^{R 19} in (5-1) can be mentioned.

Examples of the alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ^{1 to} R ⁸ include groups similar to those exemplified as R ¹³ , R ¹⁴ and R ¹⁵ in the above formula (3). Is mentioned.

Examples of the aromatic hydrocarbon group having 6 to 20 carbon atoms represented by R ^{4 to} R ⁸ include the same groups as those exemplified as R ¹⁹ in the above formula (5-1).

  In these, a hydrogen atom, an alkyl group, and a cycloalkyl group are preferable, a hydrogen atom, a C1-C5 alkyl group, and a C3-C10 cycloalkyl group are more preferable, a hydrogen atom, a methyl group, and an ethyl group More preferred is a cyclohexyl group.

Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ⁴ and R ⁵ include, for example,
Fluorinated alkyl groups such as fluoromethyl group, trifluoromethyl group, trifluoroethyl group, pentafluoro-n-propyl group, hexafluoro-i-propyl group, nonafluoro-n-butyl group;
Examples thereof include fluorinated cycloalkyl groups such as a fluorocyclopentyl group, a difluorocyclopentyl group, a cyclopentyl difluoropropyl group, and a perfluorocyclohexyl group.

It is preferable that at least one of the R ⁴ and R ⁵ is a fluorine atom or a fluorinated alkyl group, more that R ⁴ and R ⁵ is a fluorinated alkyl group having a fluorine atom or having 1 to 20 carbon atoms More preferably, R ⁴ and R ⁵ are each a fluorine atom or a C 1-20 perfluoroalkyl group, and R ⁴ and R ⁵ are particularly preferably a fluorine atom or a trifluoromethyl group, and R ⁴ And R ⁵ is more preferably a fluorine atom.

Examples of the ring structure constituted by two or more bonds among the groups represented by R ^{1 to} R ³ include, for example,
Monocyclic cycloalkane structures such as cyclopropane structure, cyclobutane structure, cyclopentane structure, cyclohexane structure, cyclooctane structure;
Polycyclic cycloalkane structures such as norbornane structure, adamantane structure, tricyclodecane structure and tetracyclododecane structure;
Monocyclic cycloalkene structures such as cyclopropene structure, cyclobutene structure, cyclopentene structure, cyclohexene structure, cyclooctene structure;
Polycyclic cycloalkene structures such as norbornene structure, tricyclodecene structure, tetracyclododecene structure;
Examples thereof include aromatic ring structures such as a benzene structure, a naphthalene structure, an anthracene structure, and a phenanthrene structure.

  Among these, a cycloalkane structure and an aromatic ring structure are preferable, a polycyclic cycloalkane structure and an aromatic ring structure are more preferable, a polycyclic cycloalkane structure having 7 to 12 carbon atoms, and an aromatic ring having 6 to 12 carbon atoms The structure is more preferable, and an adamantane structure, a carbonyl adamantane structure, and a benzene structure are particularly preferable.

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

  n is an integer of 1 or 2, and 1 is preferable.

A is —O— or —NR ⁸ —, preferably —O—.

When A is —O— and R ¹ R ² R ³ C— is an acid-dissociable group, the acid-dissociable group is dissociated by the acid generated by irradiation with radiation, and the polarity is further increased. B] The diffusion of the acid generated from the acid generator is moderately shortened.

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

In the above formula (2), R ⁹ is a fluorine atom, a hydroxy group, an alkyl group having 1 to 10 carbon atoms, a fluorinated alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or 2 to 2 carbon atoms. 11 alkoxycarbonyl groups or alkylsulfonyl groups having 1 to 10 carbon atoms. j is an integer of 0-9. When j is 2 or more, the plurality of R ⁹ may be the same or different. R ¹⁰ and R ¹¹ are each independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or these groups are combined with each other. It represents a ring structure having 4 to 10 ring members that is constituted together with the sulfur atom to which they are bonded. k is an integer of 0-2.

Examples of the alkyl group having 1 to 10 carbon atoms represented by R ⁹ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, and a sec-butyl group. , T-butyl group and the like.

Examples of the alkoxy group having 1 to 10 carbon atoms represented by R ⁹ include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, i-butoxy group, sec-butoxy group, t -Butoxy group etc. are mentioned.

Examples of the alkoxycarbonyl group having 2 to 11 carbon atoms represented by R ⁹ include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group, an n-butoxycarbonyl group, and an i-butoxycarbonyl group. , Sec-butoxycarbonyl group, t-butoxycarbonyl group and the like.

Examples of the alkylsulfonyl group having 1 to 10 carbon atoms represented by R ⁹ include a methylsulfonyl group, an ethylsulfonyl group, an n-propylsulfonyl group, an i-propylsulfonyl group, an n-butylsulfonyl group, and an i-butylsulfonyl group. , Sec-butylsulfonyl group, t-butylsulfonyl group and the like.

R ⁹ is preferably an alkyl group or an alkoxy group, more preferably a methyl group, a t-butyl group, a methoxy group, an n-butoxy group, or a t-butoxy group.

  j is preferably an integer of 0 to 2, more preferably 0 or 1, and still more preferably 0.

Examples of the alkyl group having 1 to 10 carbon atoms represented by R ¹⁰ and R ¹¹ include the same groups exemplified as the alkyl group represented by R ⁹ above.

Examples of the aryl group having 1 to 10 carbon atoms represented by R ¹⁰ and R ¹¹ include a phenyl group, a tolyl group, a xylyl group, a mesityl group, a naphthyl group, a methylnaphthyl group, an anthryl group, And methyl anthryl group.

  Examples of the ring structure having 4 to 10 ring members constituted by the sulfur atoms to which these groups are combined and bonded to each other include a thiophenium structure, a dihydrothiophenium structure, a tetrahydrothiophenium structure, and a benzothiophenium structure. Examples include a structure and a dibenzothiophenium structure.

  k is preferably an integer of 0 or 1, and more preferably 0.

  Examples of the cation represented by the above formula (2) include cations represented by the following formulas (2-1) to (2-13).

  Among these, a cation represented by the above formula (2-1) is preferable.

  Examples of the compound (1) include compounds represented by the following formulas (i-1) to (i-20) (hereinafter also referred to as “compounds (i-1) to (i-20)”). .

In the above formulas (i-1) to (i-20), M ⁺ has the same meaning as in the above formula (1).

  Among these, compounds (i-1) to (i-10) are preferable.

The compound (1) is represented, for example, by the following reaction scheme:
(A) A compound represented by the following formula (ia) and a dithionite alkali metal salt represented by E ₂ S ₂ O ₄ are reacted to form a sulfine represented by the following formula (ib). Obtaining an acid salt,
(B) a step of reacting the sulfinate (ib) with hydrogen peroxide to obtain a sulfonate represented by the following formula (ic); and (C) the sulfonate (i- It can be synthesized by a compound synthesis method comprising a step of reacting c) with an onium salt represented by M ⁺ Y ⁻ to obtain a compound represented by the following formula (1).

In the above scheme, R ¹ , R ² and R ³ are each independently a chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or Two or more of these groups are combined with each other to represent a ring structure having 3 to 20 ring members constituted with the carbon atom to which they are bonded. R ⁴ and R ⁵ are each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. m is an integer of 1-3. When m is 2 or more, the plurality of R ⁴ may be the same or different, and the plurality of R ⁵ may be the same or different. However, at least one of R ⁴ and R ⁵ is a fluorine atom or a fluorinated hydrocarbon group. R ⁶ and R ⁷ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. n is 1 or 2. When n is 2, the plurality of R ⁶ may be the same or different, and the plurality of R ⁷ may be the same or different. A is —O— or —NR ⁸ —. R ⁸ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. X is a halogen atom. E is an alkali metal. Y ⁻ is a monovalent anion. M ⁺ is a monovalent radiation-sensitive onium cation.

E is preferably sodium.
X is preferably a chlorine atom or a bromine atom, more preferably a bromine atom.
Y is preferably a chlorine atom or a bromine atom, and more preferably a chlorine atom.

In the step (A), the compound (ia) is reacted with an alkali metal dithionite represented by E ₂ S ₂ O ₄ in an organic solvent in the presence of a base such as sodium bicarbonate. Thus, the sulfinate (ib) is obtained.
In the step (B), the sulfinate (ic) is obtained by reacting the sulfinate (ib) with hydrogen peroxide.
Subsequently, in the step (C), the compound ((c)) and the onium salt represented by M ⁺ Y ⁻ are reacted in a solvent such as dichloromethane / water, for example. 1) is obtained. The produced compound (1) can be isolated by purification by column chromatography.

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

<[C] Other acid generators>
[C] The other acid generator is a radiation sensitive acid generator other than the [B] acid generator. [C] Examples of other acid generators include [C1] other acid generators that generate stronger acids than acids generated from [B] acid generators, and acids that are weaker than acids generated from [B] acid generators. Radiation sensitive acid generators (hereinafter referred to as “[C2] other acid generators”), [C1] other acid generators and [C2] other acid generators (hereinafter also referred to as “[C2] other acid generators”). And “[C3] Other acid generators”).
[C1] The other acid generator includes, for example, a radiation-sensitive onium cation and an anion having SO ₃ ⁻ and having two fluorine atoms bonded to the carbon atom adjacent to the SO ₃ ^−. Compounds and the like.
[C2] Other acid generators include, for example, a radiation-sensitive onium cation, SO ₃ ^— , a carbon atom adjacent to this SO ₃ ^— , a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a carbon number. compounds composed of an anion which is a fluorinated alkyl group of 1 to 20 are attached, a radiation-sensitive onium cations, COO ^- include the compounds consisting of an anion having.
[C1] According to another acid generator, the acid generated by exposure dissociates the acid dissociable group of the [A] polymer, and as a result, the solubility of the [A] polymer in the developer changes. A resist pattern can be formed. Also, [C2] Other acid generators in the unexposed area SO ₃ ^- or COO ^- is high acid trapping function by basic with is exhibited by protons generated in the exposed portion, the SO ₃ ^- Becomes SO ₃ H and COO ⁻ becomes COOH, and its acid trapping function is lowered, so that it functions as an acid diffusion control agent. [C] Other acid generators may be used alone or in combination of two or more.

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

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

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

[C2] Other acid generators include, for example,
Examples of the sulfonium salt include triphenylsulfonium salicylate, triphenylsulfonium 10-camphor salicylate,
Examples of the tetrahydrothiophenium salt include 4-hydroxy-1-naphthyltetrahydrothiophenium salicylate, 4-hydroxy-1-naphthyltetrahydrothiophenium 10-camphorsulfonate, 1- (1-naphthylacetomethyl) tetrahydrothio Phenium salicylate, 1- (1-naphthylacetomethyl) tetrahydrothiophenium 10-camphorsulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium salicylate, 1- (3 , 5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 10-camphorsulfonate, etc.
Examples of the iodonium salt include diphenyliodonium salicylate, diphenyliodonium 10-camphor sulfonate, bis (4-t-butylphenyl) iodonium salicylate, bis (4-t-butylphenyl) iodonium 10-camphorsulfonate, and the like. .
[C2] As other acid generators, onium salt compounds are preferable, sulfonium salts are more preferable, triphenylsulfonium salts are more preferable, and triphenylsulfonium salicylate and triphenylsulfonium 10-camphorsulfonate are particularly preferable.

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

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

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

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

  Examples of the amine compound include mono (cyclo) alkylamines such as n-pentylamine and cyclohexylamine; di (cyclo) alkylamines such as din-pentylamine and dicyclohexylamine; tri-n-pentylamine and tri Tri (cyclo) alkylamines such as cyclohexylamine; substituted alkylanilines such as 2,6-dii-propylaniline and 2,6-din-propylaniline or derivatives thereof; ethylenediamine, N, N, N ′, N '-Tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylamine, 2,2- Bis (4-aminophenyl) Propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4-aminophenyl) -2 -(4-hydroxyphenyl) propane, 1,4-bis (1- (4-aminophenyl) -1-methylethyl) benzene, 1,3-bis (1- (4-aminophenyl) -1-methylethyl ) Benzene, bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) ether, 1- (2-hydroxyethyl) -2-imidazolidinone, 2-quinoxalinol, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, N, N, N ′, N ″ N ″ -pentamethyldiethylenetriamine and the like can be mentioned.

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

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

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

  Of these, nitrogen-containing heterocyclic compounds and amine compounds are preferred, and N- (undecan-1-ylcarbonyloxyethyl) morpholine, 2,6-di-propylaniline, and tri-n-pentylamine are more preferred.

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

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

  [E] The polymer is not particularly limited, but (1) the polymer itself is insoluble in the developer and becomes alkali-soluble by the action of an acid, and (2) the polymer itself is soluble in the developer, and the acid. (3) a polymer that itself is insoluble in a developer and becomes alkali-soluble by the action of an alkali, (4) itself is soluble in a developer, Examples thereof include polymers whose alkali solubility is increased by action.

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

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

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

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

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

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

In said formula (6), ^Rf1 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^f2 is a substituted or unsubstituted monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms or a substituted or unsubstituted monovalent fluorinated alicyclic hydrocarbon group having 4 to 20 carbon atoms. .

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

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

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

  Examples of the structural unit (f1) include a structural unit represented by the following formula (6-1) and a structural unit represented by (6-2).

In the formulas (6-1) and (6-2), R ^f1 has the same ^meaning as the formula (6).

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

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

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

In the above formula (7), R ^f3 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ^f4 is a (r + 1) -valent linking group. X ¹ is a divalent linking group having a fluorine atom. R ^f5 is a hydrogen atom or a monovalent organic group. r is an integer of 1 to 3. However, when r is 2 or 3, the plurality of X ¹ and R ^f5 may be the same or different.

Examples of the (r + 1) -valent linking group represented by R ^f4 include, for example, a linear or branched hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, and carbon. An aromatic hydrocarbon group of 6 to 30 or a combination of these groups and one or more groups selected from the group consisting of oxygen atom, sulfur atom, ether group, ester group, carbonyl group, imino group and amide group Groups. The (r + 1) -valent linking group may have a substituent.

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

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

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

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

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

Examples of the monovalent organic group represented by R ^f5 include a linear or branched hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, and 6 carbon atoms. To 30 aromatic hydrocarbon groups, or a combination of these groups and one or more groups selected from the group consisting of oxygen, sulfur, ether, ester, carbonyl, imino and amide groups Etc.

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

In the above formula (7-1), R ^f4 is a divalent linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. R ^f3 , X ¹ and R ^f5 are synonymous with the above formula (7).
In the above formula (7-2), R ^f3 , X ¹ , R ^f5 and r are as defined in the above formula (7). However, when r is 2 or 3, the plurality of X ¹ and R ^f5 may be the same or different.

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

In the formulas (7-1-1) to (7-1-3) and the formula (7-2-1), R ^f3 has the same meaning as the formula (7).

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

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

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

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

  As a content rate of another structural unit, 5 mol%-90 mol% are preferable with respect to all the structural units which comprise a [E] polymer, 10 mol%-80 mol% are more preferable, 20 mol%- 70 mol% is more preferable.

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

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

<[E] Polymer Synthesis Method>
[E] The polymer can be produced, for example, by polymerizing a monomer corresponding to each predetermined structural unit in a suitable polymerization solvent using a radical polymerization initiator.

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

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

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

  [E] As a ratio (Mw / Mn) of Mw and Mn of the polymer, 1 to 5 is preferable, and 1 to 3 is more preferable.

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

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

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

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

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

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

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

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

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

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

  Examples of the nitrile compound include succinonitrile.

  Examples of the polyhydric alcohol include glycerin.

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

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

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

<Method for preparing radiation-sensitive resin composition>
In the radiation-sensitive resin composition, [A] a polymer, [B] an acid generator, and optionally [C] other optional components such as other acid generators and [F] solvent are mixed in a predetermined ratio. Can be prepared.

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

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

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

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

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

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

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

  Examples of the alkali developer include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, Methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4.3.0] -5-nonene and the like, an alkaline aqueous solution in which at least one kind of alkaline compound is dissolved may be mentioned. Among these, a TMAH aqueous solution is preferable, and a 2.38 mass% TMAH aqueous solution is more preferable.

As the organic solvent developer, for example,
Alcohol solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol;
Ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, tetrahydrofuran, dioxane, diphenyl ether, anisole;
Ketone solvents such as acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone;
Amide solvents such as N, N′-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide;
Examples include ester solvents such as diethyl carbonate, methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, and n-butyl acetate.
Among these, ester solvents are preferable, acetate ester solvents are more preferable, and n-butyl acetate is more preferable. As content of the organic solvent in a developing solution, 80 mass% or more is preferable, 90 mass% or more is more preferable, 95 mass% or more is further more preferable, 99 mass% or more is especially preferable. Examples of components other than the organic solvent in the developer include water and silicone oil.

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

<Radiation sensitive acid generator>
The radiation sensitive acid generator of this invention consists of a compound represented by the said Formula (1). Since the said radiation sensitive acid generator has the above-mentioned characteristic, the LWR performance etc. of the radiation sensitive resin composition containing this can be improved.

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

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

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In addition, each measurement in an Example and a comparative example was performed with the following method.

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

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

<Synthesis of compounds>
[Example 1] (Synthesis of Compound (S-1))
(3s, 5s, 7s) -adamantan-1-yl 3-bromo-2,2-difluoropentanoate 3.51 g (10.0 mmol), sodium bicarbonate 2.52 g (30.0 mmol), sodium dithionite 3.48 g (20.0 mmol), 50 g of acetonitrile, and 50 g of water were placed in a 300 mL eggplant-shaped flask and heated and stirred at 65 ° C. for 4 hours under a nitrogen atmosphere. After confirming the disappearance of the raw material by thin layer chromatography (TLC), it was cooled to room temperature and the aqueous layer was removed. After washing once with saturated saline, only the organic layer was recovered and added to a 300 mL eggplant-shaped flask. Thereto was added 3.40 g (30.0 mmol) of 30% by mass hydrogen peroxide and the mixture was heated and stirred at 45 ° C. for 6 hours. After air cooling to room temperature, 10% by mass aqueous sodium hydrogen sulfite solution was added to quench excess peroxide. Dichloromethane was added and the organic layer was recovered, followed by washing with water twice. After distilling off the solvent, 2.99 g (10.0 mmol) of triphenylsulfonium chloride, 80 g of dichloromethane and 40 g of water were added and stirred at room temperature for 6 hours. The organic layer was collected, washed four times with water, and purified by column chromatography to obtain 4.80 g (yield 78%) of a compound represented by the following formula (S-1).

[Examples 2 to 10] (Synthesis of compounds (S-2) to (S-10))
By appropriately selecting a precursor and performing the same operation as in Example 1, compounds represented by the following formulas (S-2) to (S-10) were synthesized.

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

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

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

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

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

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

<Preparation of radiation-sensitive resin composition>
[B] acid generator, [C1] other acid generator, [C2] other acid generator, [D] compound, [F] solvent, and [G] uneven distribution used for the preparation of the radiation sensitive resin composition The conversion accelerator is shown below.

[[B] acid generator]
S-1 to S-10: Compounds represented by the above formulas (S-1) to (S-10)

[[C1] Other acid generators]
C1-1: Triphenylsulfonium 2- (adamantan-1-ylcarbonyloxy) -1,1,3,3,3-pentafluoropropane-1-sulfonate (compound represented by the following formula (C1-1))
C1-2: Triphenylsulfonium norbornane sultone-2-yloxycarbonyldifluoromethanesulfonate (compound represented by the following formula (C1-2))
C1-3: Triphenylsulfonium 3- (piperidin-1-ylsulfonyl) -1,1,2,2,3,3-hexafluoropropane-1-sulfonate (a compound represented by the following formula (C1-3) )
[[C2] Other acid generators]
C2-1: Triphenylsulfonium salicylate (compound represented by the following formula (C2-1))
C2-2: Triphenylsulfonium 10-camphorsulfonate (compound represented by the following formula (C2-2))

[[D] Compound]
D-1: N- (n-undecan-1-ylcarbonyloxyethyl) morpholine (compound represented by the following formula (D-1))
D-2: 2,6-dii-propylaniline (compound represented by the following formula (D-2))
D-3: Tri-n-pentylamine (compound represented by the following formula (D-3))

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

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

[Preparation of radiation-sensitive resin composition (J1) for ArF exposure]
[Example 11]
[A] 100 parts by mass of (A-1) as a polymer, [B] 2.3 parts by mass of (S-1) as an acid generator, [C1] (C1-1) as another acid generator 8.5 parts by mass, 3 parts by mass of polymer (E-1) as [E] polymer, 2,240 parts by mass of solvent (F-1) as solvent [F] and 960 parts by mass of solvent (F-2) And 30 parts by mass of the uneven distribution accelerator (G-1) as the [G] uneven distribution accelerator, and filtered through a membrane filter having a pore diameter of 0.2 μm (J1-1) ) Was prepared.

[Examples 12 to 38 and Comparative Examples 1 to 5]
Except having used each component of the kind and content shown in the following Table 1 and Table 2, it operated similarly to Example 11 and the radiation sensitive resin composition (J1-2)-(J1-28) and ( CJ1-1) to (CJ1-5) were prepared.

[Preparation of Radiation Sensitive Resin Composition (J2) for Electron Beam Exposure]
[Example 39]
[A] 100 parts by mass of (A-4) as a polymer, [B] 3.6 parts by mass of (S-1) as an acid generator, [C1] (C1-1) as another acid generator 20 parts by mass and (F-1) 4,280 parts by mass as [F] solvent and (F-2) 1,830 parts by mass are mixed and filtered through a membrane filter having a pore size of 0.2 μm. Resin composition (J2-1) was prepared.

[Examples 40 to 64 and Comparative Examples 6 to 10]
Except having used each component of the kind and content shown in following Table 3 and Table 4, it operated similarly to Example 39, and the radiation sensitive resin compositions (J2-2)-(CJ2-26) and ( CJ2-1) to (CJ2-5) were prepared.

<Formation of resist pattern>
(In the case of ArF exposure)
[Formation of resist pattern (1)]
A 12-inch silicon wafer surface was coated with a composition for forming a lower antireflection film (“ARC66” from Brewer Science Co., Ltd.) using a spin coater (“CLEAN TRACK ACT12” from Tokyo Electron), and then 205 ° C. Was heated for 60 seconds to form a lower antireflection film having a thickness of 105 nm. On the lower antireflection film, the prepared radiation sensitive resin composition for ArF exposure (J1) was applied using the spin coater, and PB was performed at 90 ° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with a film thickness of 90 nm. Next, this resist film was subjected to an optical condition of NA = 1.3 and dipole (Sigma 0.977 / 0.782) using an ArF excimer laser immersion exposure apparatus (“NSR-S610C” manufactured by NIKON). , Exposed through a 40 nm line and space (1L1S) mask pattern. After the exposure, PEB was performed at 90 ° C. for 60 seconds. Thereafter, an alkali development was performed using an aqueous 2.38 mass% tetramethylammonium hydroxide (TMAH) solution as an alkali developer, washed with water, and dried to form a positive resist pattern. When this resist pattern is formed, the line width formed through a one-to-one line and space mask having a target dimension of 40 nm is defined as an optimum exposure amount. did.

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

(In the case of electron beam exposure)
[Formation of resist pattern (3)]
Spin coater (Tokyo Electron's “CLEAN” on the surface of 8-inch silicon wafer
TRACK ACT8 ") was applied to the prepared radiation sensitive resin composition for electron beam exposure (J2) and PB was performed at 90 ° C for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with a film thickness of 50 nm. Next, the resist film was irradiated with an electron beam by using a simple electron beam drawing apparatus (“HL800D” manufactured by Hitachi, Ltd., output: 50 KeV, current density: 5.0 A / cm ² ). After irradiation, PEB was performed at 120 ° C. for 60 seconds. Thereafter, development was performed at 23 ° C. for 30 seconds using a 2.38 mass% TMAH aqueous solution as an alkaline developer, washed with water, and dried to form a positive resist pattern.

<Evaluation>
About the resist pattern formed using each said radiation sensitive resin composition, LWR performance, resolution, rectangularity of a cross-sectional shape, and depth of focus were evaluated in accordance with the following method. The results are shown in Table 5 and Table 6, respectively. A scanning electron microscope (Hitachi High-Technologies “S-9380”) was used for measuring the resist pattern. As comparative examples to be compared for LWR performance, resolution, and depth of focus, Comparative Examples 1 for Examples 11 to 20 and 25 to 34, and Comparative Example 2 for Examples 21 and 35 Comparative Example 3 for Examples 22 and 36, Comparative Example 4 for Examples 23 and 37, Comparative Example 5 for Examples 24 and 38, Examples 39 to 48 and Examples Comparative Example 6 for Examples 51-60, Comparative Example 7 for Example 49 and Example 61, Comparative Example 8 for Example 50 and Example 62, Comparative Example 9 for Example 63, and Example Example 64 was Comparative Example 10. In Tables 5 and 6, “-” represents a criterion.

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

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

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

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

  As is apparent from the results in Tables 5 and 6, the radiation-sensitive resin compositions of the examples were rectangular in LWR performance, resolution, and cross-sectional shape both in the case of ArF exposure and in the case of alkali development and organic solvent development. Excellent in depth and depth of focus. Further, in the case of electron beam exposure and alkali development, the LWR performance, resolution, and cross-sectional rectangularity are excellent. In the radiation-sensitive resin composition of the comparative example, these characteristics are inferior to those of the examples. In general, it is known that the electron beam exposure shows the same tendency as in the case of EUV exposure. Therefore, according to the radiation-sensitive resin composition of the example, in the case of EUV exposure. Is presumed to be excellent in LWR performance and the like.

  According to the radiation sensitive resin composition and the resist pattern forming method of the present invention, it is possible to form a resist pattern having excellent LWR performance, resolution, and cross-sectional rectangularity while exhibiting excellent depth of focus. The radiation sensitive acid generator of this invention can be used suitably as a component of the said radiation sensitive resin composition. The compound of the present invention can be suitably used as the radiation sensitive acid generator. Therefore, these can be suitably used for manufacturing processes of semiconductor devices, which are expected to be further miniaturized in the future.

Claims (9)

Containing a polymer having a first structural unit containing an acid-dissociable group, and a first radiation-sensitive acid generator;
The radiation sensitive resin composition which the said 1st radiation sensitive acid generator consists of a compound represented by following formula (1).

(In the formula (1), R ¹ , R ² and R ³ are each independently a chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. Or a ring structure having 3 to 20 ring members constituted by carbon atoms to which two or more of these groups are combined with each other and bonded to each other, and R ⁴ and R ⁵ are each independently hydrogen An atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, m is an integer of 1 to 3. m is 2 or more. In this case, a plurality of R ⁴ may be the same or different, and a plurality of R ⁵ may be the same or different, provided that at least one of R ⁴ and R ⁵ is a fluorine atom or a fluorinated hydrocarbon. is a group .R ⁶ and R ⁷ are each independently hydrogen atom or a carbon atoms Is a monovalent hydrocarbon group having to 20 .n, when is 1 or 2 .n is 2, a plurality of R ⁶ may be the same or different, a plurality of R ⁷ is either the same or different A is —O— or —NR ⁸ —, R ⁸ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and M ⁺ is a monovalent radiation-sensitive onium. Cation.) The radiation sensitive resin composition according to claim 1, wherein R ⁴ and R ⁵ in the formula (1) are a fluorine atom or a C 1-20 perfluoroalkyl group. The radiation sensitive resin composition of Claim 1 or Claim 2 with which the radiation sensitive onium cation of M ^<+> in the said Formula (1) is represented by following formula (2).

(In Formula (2), R ⁹ is a fluorine atom, a hydroxy group, an alkyl group having 1 to 10 carbon atoms, a fluorinated alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or 2 to 2 carbon atoms. 11 is an alkoxycarbonyl group or an alkylsulfonyl group having 1 to 10 carbon atoms, j is an integer of 0 to ^9. When j is 2 or more, a plurality of R ⁹ may be the same or different. R ¹⁰ and R ¹¹ are each independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, or these groups are combined with each other. A ring structure having 4 to 10 ring members constituted together with the sulfur atom to which they are bonded is represented.k is an integer of 0 to 2.)   The radiation-sensitive resin composition according to claim 1, 2 or 3, further comprising a second radiation-sensitive acid generator that generates an acid stronger than the acid generated from the first radiation-sensitive acid generator. object. The radiation sensitive resin composition according to any one of claims 1 to 4, wherein the first structural unit is represented by the following formula (3).

(In Formula (3), R ¹² is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ¹³ is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ¹⁴ and R ¹⁵ are each independently a chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or these groups are combined with each other and bonded to each other. (Represents an alicyclic structure having 3 to 20 carbon atoms and carbon atoms) The radiation sensitive resin composition according to any one of claims 1 to 5, wherein the polymer further has a second structural unit represented by the following formula (4).

(In Formula (4), R ¹⁶ is a hydrogen atom or a methyl group. R ¹⁷ is a monovalent organic group having 1 to 20 carbon atoms. P is an integer of 0 to 3. In the case of 2 or 3, a plurality of R ¹⁷ may be the same or different, q is an integer of 1 to 3, provided that p + q is 5 or less. Forming a resist film;
A step of exposing the resist film, and a step of developing the exposed resist film,
The resist pattern formation method which forms the said resist film with the radiation sensitive resin composition of any one of Claims 1-6. The radiation sensitive acid generator which consists of a compound represented by following formula (1).

(In the formula (1), R ¹ , R ² and R ³ are each independently a chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. Or a ring structure having 3 to 20 ring members constituted by carbon atoms to which two or more of these groups are combined with each other and bonded to each other, and R ⁴ and R ⁵ are each independently hydrogen An atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, m is an integer of 1 to 3. m is 2 or more. In this case, a plurality of R ⁴ may be the same or different, and a plurality of R ⁵ may be the same or different, provided that at least one of R ⁴ and R ⁵ is a fluorine atom or a fluorinated hydrocarbon. is a group .R ⁶ and R ⁷ are each independently hydrogen atom or a carbon atoms Is a monovalent hydrocarbon group having to 20 .n, when is 1 or 2 .n is 2, a plurality of R ⁶ may be the same or different, a plurality of R ⁷ is either the same or different A is —O— or —NR ⁸ —, R ⁸ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and M ⁺ is a monovalent radiation-sensitive onium. Cation.) A compound represented by the following formula (1).

(In the formula (1), R ¹ , R ² and R ³ are each independently a chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. Or a ring structure having 3 to 20 ring members constituted by carbon atoms to which two or more of these groups are combined with each other and bonded to each other, and R ⁴ and R ⁵ are each independently hydrogen An atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms, m is an integer of 1 to 3. m is 2 or more. In this case, a plurality of R ⁴ may be the same or different, and a plurality of R ⁵ may be the same or different, provided that at least one of R ⁴ and R ⁵ is a fluorine atom or a fluorinated hydrocarbon. is a group .R ⁶ and R ⁷ are each independently hydrogen atom or a carbon atoms Is a monovalent hydrocarbon group having to 20 .n, when is 1 or 2 .n is 2, a plurality of R ⁶ may be the same or different, a plurality of R ⁷ is either the same or different A is —O— or —NR ⁸ —, R ⁸ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and M ⁺ is a monovalent radiation-sensitive onium. Cation.)