JPWO2011115190A1 - Radiation sensitive resin composition - Google Patents

Abstract

An object of the present invention is to provide a radiation-sensitive resin composition having a low LWR and capable of forming a resist pattern having an excellent pattern shape. [A] Structural unit (I) represented by the following formula (1) It is a radiation sensitive resin composition containing the acid dissociable group-containing polymer having a [B] compound represented by the following formula (2). M + in the following formula (1) is preferably at least one onium cation selected from the group consisting of onium cations represented by the following formula (3) and the following formula (4), respectively.

Description

  The present invention relates to a radiation-sensitive resin composition used in a semiconductor manufacturing process such as an IC, a circuit board such as a liquid crystal or a thermal head, and other photolithography processes.

  The chemically amplified radiation-sensitive resin composition generates an acid in an exposed area by irradiation with far ultraviolet light or the like typified by a KrF excimer laser or an ArF excimer laser, and reacts with the acid as a catalyst to react with the exposed area. It is a composition that changes the dissolution rate of the unexposed portion with respect to the developer to form a resist pattern on the substrate.

  When more precise line width control is performed, for example, when the device design dimension is sub-half micron or less, the chemically amplified resist not only has excellent resolution performance but also resist pattern line. It has become important that LWR (Line Width Roughness), which is an index of variation in width, is small and the pattern shape is rectangular. In order to control such a fine shape, it is important to control the diffusion rate of the produced acid. As a method therefor, a technique for adding a basic compound to a radiation-sensitive resin composition has been studied. In particular, an acid diffusion control agent that loses acid diffusion controllability by being dissociated by an acid generated in an exposed area is added. Thus, it is known that the contrast between the exposed portion and the unexposed portion can be improved (see Japanese Patent Publication No. 2-27660 and Japanese Patent Laid-Open No. 2009-53688). However, even with this technique, the performance of LWR, pattern shape, etc. is still insufficient.

JP-B-2-27660 JP 2009-53688 A

  This invention is made | formed based on the above situations, The objective is to provide the radiation sensitive resin composition which can form the resist pattern which is small in LWR and excellent in pattern shape.

（式（１）中、Ｒ^１は、水素原子、フッ素原子、トリフルオロメチル基又は炭素数１〜３のアルキル基である。Ｅは、単結合又は−ＣＯＯ−である。Ｒ^２は、炭素数１〜２０の２価の炭化水素基であり、この炭化水素基の水素原子の一部又は全部はフッ素原子で置換されていてもよい。ｎは、０〜５の整数である。Ｍ^＋は、オニウムカチオンである。）

（式（２）中、Ｙは、水素原子、ヒドロキシル基、アクリロイル基又はメタクリロイル基である。Ｒ^３は、炭素数１〜２０の２価の炭化水素基又は−Ｒ−Ｚ−Ｒ’−である。Ｒ及びＲ’は、それぞれ独立して、炭素数１〜２０の２価の炭化水素基である。Ｚは、−Ｏ−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＮＨ−、−ＮＨＣＯ−又は−ＣＯＮＨ−である。但し、ＲとＲ’とが互いに結合して、Ｚと共に環構造を形成していてもよい。Ｘ⁻は、−Ｏ⁻、−ＣＯＯ⁻、−ＳＯ_３ ⁻又は−Ｎ⁻−ＳＯ_２−Ｒ”である。Ｒ”は、炭素数１〜２０の１価の炭化水素基であり、この炭化水素基の水素原子の一部又は全部はフッ素原子で置換されていてもよい。Ｑ^＋は、オニウムカチオンである。）The invention made to solve the above problems is
[A] An acid-dissociable group-containing polymer having a structural unit (I) represented by the following formula (1) (hereinafter also referred to as “[A] polymer”), and [B] the following formula (2) (Hereinafter, also referred to as “[B] compound”)
Is a radiation-sensitive resin composition.

(In Formula (1), R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms. E is a single bond or —COO—. R ² is carbon. It is a divalent hydrocarbon group of 1 to 20, and some or all of the hydrogen atoms of this hydrocarbon group may be substituted with fluorine atoms, n is an integer of 0 to 5. M ⁺ Is an onium cation.)

(In Formula (2), Y is a hydrogen atom, a hydroxyl group, an acryloyl group, or a methacryloyl group. R ³ is a divalent hydrocarbon group having 1 to 20 carbon atoms or —R—Z—R′—. R and R ′ are each independently a divalent hydrocarbon group having 1 to 20 carbon atoms, Z is —O—, —CO—, —COO—, —OCO—, —NH—. , —NHCO— or —CONH—, wherein R and R ′ may be bonded to each other to form a ring structure with Z. X ⁻ represents —O ⁻ , —COO ⁻ , —SO. ₃ ^- or ^-N - "is .R a" is _-SO 2 -R, a monovalent hydrocarbon group having 1 to 20 carbon atoms, in some or all of the fluorine atoms of the hydrogen atoms of the hydrocarbon group Optionally substituted, Q ⁺ is an onium cation.)

The radiation sensitive resin composition of the present invention contains the [A] polymer having the specific structural unit (I) and the acid dissociable group and the [B] compound having the specific structure. [A] The structural unit (I) of the polymer is a unit that generates an acid upon exposure, and when it exists in the polymer, homogeneous acid diffusion occurs, and from the exposed area to the unexposed area. Acid diffusion is controlled. The [B] compound diffuses acid in the exposed area and controls acid diffusion in the unexposed area.
According to the radiation-sensitive resin composition, acid diffusion is highly controlled by the combination of the [A] polymer and the [B] compound, and as a result, a resist pattern having a small LWR and an excellent pattern shape is formed. can do.

（式（３）中、Ｒ^４a、Ｒ^４ｂ及びＲ^４ｃは、それぞれ独立して、炭素数１〜３０の１価の炭化水素基又は核原子数４〜３０の１価の複素環基である。但し、上記炭化水素基及び複素環基の水素原子の一部又は全部は置換されていてもよい。また、Ｒ^４a、Ｒ^４ｂ及びＲ^４ｃのうちいずれか２つが互いに結合して、それらが結合するイオウ原子と共に環状構造を形成していてもよい。）

（式（４）中、Ｒ^５ａ及びＲ^５ｂは、それぞれ独立して、炭素数１〜３０の１価の炭化水素基又は核原子数４〜３０の１価の複素環基である。但し、上記炭化水素基及び複素環基の水素原子の一部又は全部は置換されていてもよい。また、Ｒ^５ａ及びＲ^５ｂが互いに結合して、それらが結合するヨウ素原子と共に環状構造を形成していてもよい。）M ⁺ in the above formula (1) is preferably at least one onium cation selected from the group consisting of onium cations represented by the following formula (3) and the following formula (4), respectively.

(In formula (3), R ^4a , R ^4b and R ^4c are each independently a monovalent hydrocarbon group having 1 to 30 carbon atoms or a monovalent heterocyclic group having 4 to 30 carbon atoms. However, part or all of the hydrogen atoms of the hydrocarbon group and heterocyclic group may be substituted, and any two of R ^4a , R ^4b and R ^4c are bonded to each other, and (A cyclic structure may be formed with the sulfur atom to be bonded.)

(In Formula (4), R ^5a and R ^5b are each independently a monovalent hydrocarbon group having 1 to 30 carbon atoms or a monovalent heterocyclic group having 4 to 30 nucleus atoms, provided that Some or all of the hydrogen atoms of the hydrocarbon group and heterocyclic group may be substituted, and R ^5a and R ^5b are bonded to each other to form a cyclic structure together with the iodine atom to which they are bonded. May be.)

When the onium cation represented by M ⁺ in the [A] polymer has the specific structure, the sensitivity of the radiation-sensitive resin composition is improved, and as a result, the LWR of the resulting resist pattern is further suppressed. In addition, the pattern shape is excellent.

（式（２−１）〜（２−６）中、Ｒ^６は、炭素数１〜６の１価の鎖状炭化水素基である。Ｒ^７は、それぞれ独立して、炭素数１〜６の２価の鎖状炭化水素基である。Ｑ^＋の定義は上記式（２）と同じである。）[B] The compound is preferably at least one compound selected from the group consisting of compounds represented by the following formulas (2-1) to (2-6).

(In formulas (2-1) to (2-6), R ⁶ is a monovalent chain hydrocarbon group having 1 to 6 carbon atoms. R ⁷ is independently from 1 to 6 carbon atoms. (The definition of Q ⁺ is the same as in the above formula (2).)

  [B] The acid diffusion controllability is improved when the compound has the specific structure. As a result, the LWR of the resist pattern formed from the radiation sensitive resin composition is further suppressed, and the pattern shape is further excellent.

（式（５）中、Ｒ^１の定義は上記式（１）と同じである。Ｒ^８、Ｒ^９及びＲ^１０は、それぞれ独立して、炭素数１〜４のアルキル基又は炭素数４〜２０のシクロアルキル基である。但し、Ｒ^９及びＲ^１０が互いに結合して、それらが結合する炭素原子と共に、炭素数４〜２０のシクロアルカンジイル基を形成していてもよい。）[A] It is preferable that the polymer further has a structural unit (II) represented by the following formula (5).

(In the formula (5), ^.R 8, ^{R 9} and ^{R 10} defined is the same as the above formula (1) of ^{R 1} are each independently 4 alkyl group or a carbon number of 1 to 4 carbon atoms (However, R ⁹ and R ¹⁰ may be bonded to each other to form a cycloalkanediyl group having 4 to 20 carbon atoms together with the carbon atom to which they are bonded.)

  [A] The polymer further has the structural unit (II) as an acid dissociable group, so that the acid dissociation easiness is enhanced. As a result, the LWR of the resist pattern obtained from the radiation sensitive resin composition is further suppressed, and the pattern shape is further excellent.

  According to the radiation sensitive resin composition of the present invention, a resist pattern having a small LWR and an excellent pattern shape can be formed.

It is a typical top view at the time of seeing a line pattern from the upper part. It is typical sectional drawing of a line pattern shape.

<Radiation sensitive resin composition>
The radiation sensitive resin composition of the present invention contains a [A] polymer and a [B] compound. Moreover, you may contain an arbitrary component in the range which does not impair the effect of this invention. Hereinafter, each component will be described.

<[A] polymer>
[A] The polymer is an acid-dissociable group-containing polymer having the structural unit (I). The structural unit (I) is a unit that decomposes upon exposure to generate an acid, but when it exists in the [A] polymer, homogeneous acid diffusion occurs, and from the exposed area to the unexposed area. The acid diffusion is controlled. [A] The polymer is a polymer that is insoluble or hardly soluble in alkali and has a protective group (acid dissociable group) that can be removed by the action of an acid. Desorbs and shows alkali solubility. [A] The polymer may have one or more acid-dissociable groups. Although it does not specifically limit as a structural unit which has an acid dissociable group, Structural unit (II) mentioned later is mentioned as a suitable thing.

[Structural unit (I)]
The structural unit (I) is a structural unit represented by the above formula (1). In said formula (1), R < ¹ > is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or a C1-C3 alkyl group. E is a single bond or —COO—. R ² is a divalent hydrocarbon group having 1 to 20 carbon atoms, and part or all of the hydrogen atoms of the hydrocarbon group may be substituted with fluorine atoms. n is an integer of 0-5. M ⁺ is an onium cation.

Examples of the alkyl group having 1 to 3 carbon atoms represented by R ¹ include a methyl group, an ethyl group, and an n-propyl group. Among these, a hydrogen atom or a methyl group is preferable.

Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms represented by R ² include chain hydrocarbons such as a methylene group, an ethylene group, an n-propylene group, an n-butylene group, and an n-pentylene group. A divalent alicyclic hydrocarbon group in which two hydrogen atoms are removed from an alicyclic hydrocarbon such as cyclopentane, cyclohexane, dicyclopentane, tricyclodecane, tetracyclododecane, adamantane, etc .; A divalent hydrocarbon group having a hydrocarbon group in part; an aromatic hydrocarbon group such as a phenylene group, a naphthylene group or a biphenylene group; a divalent hydrocarbon group having an aromatic ring in part. In the divalent hydrocarbon group, part or all of the hydrogen atoms may be substituted with fluorine. n is preferably 1 to 4.

_{(CF 2) n} - - Preferable examples of the structure represented by _the, -CF ₂ -CF _{2 -} ^-R ₂ in the formula (1), - CHF-CF 2 -, - CF 2 -CF 2 -CF _{2 -, - CF 2 -CF 2} -CF 2 -CF 2 -, - CH 2 -CH 2 -CF 2 -CF 2 -, - CH 2 -CH 2 -CH 2 -CF 2 -CF 2 -, - CH _{2 -CH 2 -CH 2 -CH 2 -CF} 2 -CF 2 -, - CH 2 -CH 2 -CH 2 -CH 2 -CH 2 -CF 2 -CF 2 -, - CH 2 -CH 2 -CHF- _{CF 2 -, - CH 2 -CH} 2 -CH 2 -CHF-CF 2 -, - CH 2 -CH 2 -CH 2 -CH 2 -CHF-CF 2 -, - CH 2 -CH 2 -CH 2 -CH _{2 -CH 2 -CHF-CF 2 -} , - CH 2 -CF 2 -, - C _{2 -CH 2 -CF 2 -, -} CH 2 -CH 2 -CH 2 -CF 2 -, - CH 2 -CH 2 -CH 2 -CH 2 -CF 2 - and the like.

The onium cation represented by M ⁺ is preferably a sulfonium cation or an iodonium cation. The onium cation (sulfonium cation) represented by the above formula (3) and the onium cation (iodonium cation) represented by the above formula (4). At least one onium cation selected from the group consisting of

In the above formula (3), R ^4a , R ^4b and R ^4c are each independently a monovalent hydrocarbon group having 1 to 30 carbon atoms or a monovalent heterocyclic group having 4 to 30 nucleus atoms. . However, one part or all part of the hydrogen atom of the said hydrocarbon group and heterocyclic group may be substituted. Further, any two of R ^4a , R ^4b and R ^4c may be bonded to each other to form a cyclic structure together with the sulfur atom to which they are bonded.

In the above formula (4), R ^5a and R ^5b are each independently a monovalent hydrocarbon group having 1 to 30 carbon atoms or a monovalent heterocyclic group having 4 to 30 nucleus atoms. However, one part or all part of the hydrogen atom of the said hydrocarbon group and heterocyclic group may be substituted. R ^5a and R ^5b may be bonded to each other to form a cyclic structure together with the iodine atom to which they are bonded.

Examples of the hydrocarbon group having 1 to 30 carbon atoms represented by R ^4a , R ^4b and R ^{4c in the} above formula (3) and R ^5a and R ^5b in the above formula (4) include, for example, a methyl group, an ethyl group, monovalent chain hydrocarbon groups such as n-propyl group, n-butylene group, n-pentylene group; cyclobutyl group, cyclopentyl group, cyclohexyl group, dicyclopentanyl group, tricyclodecyl group, tetracyclododecyl group, A monovalent alicyclic hydrocarbon group such as an adamantyl group; a monovalent hydrocarbon group partially containing the alicyclic hydrocarbon group; a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, an o-tolyl group; m-tolyl group, p-tolyl group, p-hydroxyphenyl group, p-methoxyphenyl group, mesityl group, o-cumenyl group, 2,3-xylyl group, 2,4-xylyl group, 2,5 -Xylyl group, 2,6-xylyl group, 3,4-xylyl group, 3,5-xylyl group, p-fluorophenyl group, p-trifluoromethylphenyl group, p-chlorophenyl group, p-bromophenyl group, Examples thereof include a monovalent aromatic hydrocarbon group which may be substituted, such as a p-iodophenyl group; a monovalent hydrocarbon group partially containing the aromatic hydrocarbon group.

Examples of the monovalent heterocyclic group having 4 to 30 nuclear atoms represented by R ^4a , R ^4b and R ^{4c in the} above formula (3) and R ^5a and R ^5b in the above formula (4) include, for example, a furyl group , Thienyl group, pyranyl group, pyrrolyl group, thiantenyl group, pyrazolyl group, isothiazolyl group, isoxazolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, tetrahydropyranyl group, tetrahydrofuranyl group, tetrahydrothiopyranyl group, tetrahydrothiofuranyl group Group, 3-tetrahydrothiophene-1,1-dioxide group and the like.

  As a substituent which the said hydrocarbon group and heterocyclic group have, a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, a halogenated hydrocarbon group, an alkoxy group, an amino group, and a thiol group are preferable.

  Examples of the sulfonium cation represented by the above formula (3) include cations represented by the following formulas (i-1) to (i-27). Examples of the iodonium cation represented by the above formula (4) include cations represented by the following formulas (ii-1) to (ii-25).

  Among these, (i-1), (i-23), (ii-1), (ii-21) and (ii-22) are preferable.

The monovalent onium cation represented by M ⁺ is described in, for example, Advances in Polymer Science, Vol. 62, p. It can be synthesized according to the general method described in 1-48 (1984). [A] The polymer may contain one or more monovalent onium cations represented by the above M ⁺ .

  Examples of the structural unit (I) include structural units represented by the following formulas (1-1) to (1-10).

In the above formulas (1-1) to (1-10), the definitions of R ¹ and M ⁺ are the same as those in the above formula (1).

  Among these, structural units represented by the above formulas (1-1), (1-2), (1-4), (1-5) and (1-6) are preferable.

  Examples of the monomer that gives the structural unit (I) include polymerizable compounds represented by the following formulas (m-1-1) to (m-1-23).

  Among these, it is represented by the above formulas (m-1-1), (m-1-14), (m-1-15), (m-1-16) and (m-1-17), respectively. A polymerizable compound is preferred.

[Structural unit (II)]
[A] The polymer preferably has the structural unit (II) represented by the above formula (5) in addition to the structural unit (I). The structural unit (II) has a protective group (acid-dissociable group) that can be removed by the action of an acid, and the protective group is released by the action of an acid to cause the [A] polymer to exhibit alkali solubility. Have

In the above formula (5), the definition of R ¹ is the same as that in the above formula (1). R ⁸ , R ⁹ and R ¹⁰ are each independently an alkyl group having 1 to 4 carbon atoms or a cycloalkyl group having 4 to 20 carbon atoms. However, R ⁹ and R ¹⁰ may be bonded to each other to form a C 4-20 cycloalkanediyl group together with the carbon atom to which they are bonded.

Examples of the alkyl group having 1 to 4 carbon atoms represented by R ⁸ , R ⁹ and R ¹⁰ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and 2-methyl. A propyl group, a 1-methylpropyl group, a t-butyl group, etc. are mentioned. Among these, a methyl group and an ethyl group are preferable.

Examples of the cycloalkyl group having 4 to 20 carbon atoms represented by R ⁸ , R ⁹ and R ¹⁰ include monocyclic cycloalkyl groups such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group; Examples thereof include a cycloalkyl group having a bridged alicyclic skeleton such as a norbornyl group, a dicyclopentanyl group, a dicyclopentenyl group, a tricyclodecyl group, a tetracyclododecyl group, and an adamantyl group.

Examples of the C 4-20 cycloalkanediyl group formed by combining R ⁹ and R ¹⁰ together with the carbon atom to which they are bonded include, for example, a group obtained by removing one hydrogen atom from the cycloalkyl group Is mentioned. Of these, a cyclopentanediyl group, a cyclohexanediyl group, a cyclooctanediyl group, a norbornanediyl group, an adamantanediyl group and a tetracyclododecanediyl group are preferred, and a cyclopentanediyl group, an adamantanediyl group and a tetracyclododecanediyl group are further added. preferable.

  As the structural unit (II), structural units represented by the following formulas (5-1) to (5-17) are preferable.

In the above formula, the definition of R ¹ is the same as the above formula (1).

  Among them, the above formulas (5-2), (5-3), (5-4), (5-10), (5-11), (5-12), (5-16) and (5- 17) are preferred, and the structural units represented by the above formulas (5-2), (5-3), (5-10), (5-11) and (5-17), respectively. Is more preferable.

[Structural unit (III)]
[A] The polymer preferably has at least one structural unit (III) selected from the group consisting of a structural unit having a lactone structure and a structural unit having a cyclic carbonate structure.

Examples of the structural unit having a lactone structure include (meth) acrylic acid-5-oxo-4-oxa-tricyclo [5.2.1.0 ^3,8 ] dec-2-yl ester, (meth) acrylic acid. -10-Methoxycarbonyl-5-oxo-4-oxa-tricyclo [5.2.1.0 ^3,8 ] non-2-yl ester, (meth) acrylic acid-4-methoxycarbonyl-6-oxo-7 -Oxa-bicyclo [3.2.1] oct-2-yl ester, (meth) acrylic acid-7-oxo-8-oxa-bicyclo [3.3.1] non-2-yl ester, (meth) Acrylic acid-4-methoxycarbonyl-7-oxo-8-oxa-bicyclo [3.3.1] non-2-yl ester, (meth) acrylic acid-2-oxotetrahydropyran-4-yl ester, (Meth) acrylic acid-4-ethyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-4-propyl-2-oxotetrahydropyran-4-yl ester, (meth) acrylic acid-2, 2-dimethyl-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-4,4-dimethyl-5-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-4,4-dimethyl-2- Oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5,5-dimethyl-2-oxotetrahydrofuran-3-yl ester, (meth) acrylic acid-5-oxotetrahydrofuran-2-ylmethyl ester, (meth) Acrylic acid-3,3-dimethyl-5-oxotetrahydrofuran-2-ylmethyl ester , Structural units derived from compounds such as (meth) acrylic acid-4,4-dimethyl-5-oxotetrahydrofuran-2-ylmethyl ester, and structures represented by the following formulas (iii-1) to (iii-28) Examples include units.

In the above formula, the definition of R ¹ is the same as in the above formula (1).

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

  Examples of the structural unit having a cyclic carbonate structure include structural units represented by the following formulas (iv-1) to (iv-21).

In the above formula, the definition of R ¹ is the same as in the above formula (1).

  Among these, the structural unit represented by the above formula (iv-22) is preferable.

<Other structural units>
[A] In addition to the structural units (I) to (III), the polymer may include other structural units such as (meth) acrylic acid hydroxyalkyl ester, (meth) acrylic acid hydroxycycloalkyl ester, (meth) You may have the structural unit etc. which originate in acrylic acid hydroxyaryl ester and carboxyl group-containing (meth) acrylic acid ester. Among these, structural units derived from (meth) acrylic acid hydroxycycloalkyl ester and (meth) acrylic acid hydroxyaryl ester are preferable, respectively, (meth) acrylic acid hydroxyadamantyl ester, (meth) acrylic acid hydroxyphenyl ester and ( More preferred are structural units each derived from (meth) acrylic acid hydroxynaphthyl ester.

  In addition, the said radiation sensitive resin composition may contain 2 or more types of [A] polymers from which a copolymerization ratio and molecular weight differ, and may contain another polymer with [A] polymer. Good. Examples of the structural unit constituting the other polymer include the structural unit (II) described above and the other structural units.

  As a content rate of the said structural unit (I), Preferably it is 0.1-20 mol% with respect to all the structural units of the polymer contained in the said radiation sensitive resin composition, More preferably, it is 0.1-0.1 mol%. 15 mol%. By using it in this content ratio, effects such as improvement of the pattern shape and reduction of LWR are more fully manifested.

  As a content rate of the said structural unit (II), Preferably it is 20-80 mol% with respect to all the structural units of the polymer contained in the said radiation sensitive resin composition, More preferably, it is 25-75 mol%. is there. By using in this content ratio, a composition capable of forming a resist pattern having excellent resolution and excellent adhesion to the substrate can be obtained.

  As a content rate of the said structural unit (III), Preferably it is 10-80 mol% with respect to all the structural units of the polymer contained in the said radiation sensitive resin composition, More preferably, it is 20-70 mol%. is there. By using this content, a composition having excellent adhesion between the resist film and the substrate and excellent pattern formation can be obtained.

  The content ratio of the other structural units is preferably 40 mol% or less, more preferably 30 mol% or less, based on all the structural units of the polymer contained in the radiation-sensitive resin composition. By using in this content ratio, a composition having excellent pattern forming properties can be obtained.

<[A] Polymer Synthesis Method>
[A] The method for synthesizing the polymer is not particularly limited. For example, a polymerizable unsaturated monomer corresponding to a desired structural unit composition is converted into a radical polymerization initiator or, if necessary, chain transfer. It can synthesize | combine by superposing | polymerizing in a suitable solvent in presence of an agent. The radical polymerization initiator is preferably added so as to have a sufficiently high concentration in order to realize a sufficient polymerization rate.

  Although it does not specifically limit as said radical polymerization initiator, A thermal polymerization initiator, a redox polymerization initiator, and a photoinitiator are mentioned. Specific examples include polymerization initiators such as peroxides and azo compounds. More specific radical polymerization initiators include t-butyl hydroperoxide, t-butyl perbenzoate, benzoyl peroxide, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azo. Examples thereof include bisisobutyronitrile (AIBN), 1,1′-azobis (cyclohexanecarbonitrile), dimethyl-2,2′-azobisisobutyrate (MAIB), and the like.

  Examples of the chain transfer agent include pyrazole derivatives and alkylthiols.

  For the above polymerization operation, a usual method such as batch polymerization or dropping polymerization can be used. For example, for the monomers forming each of the structural units (I), (II) and other structural units, necessary types and amounts are dissolved in an organic solvent, a radical polymerization initiator, and a chain as necessary. [A] polymer is obtained by superposing | polymerizing in presence of a transfer agent etc. As the polymerization solvent, an organic solvent that can dissolve the monomer, radical polymerization initiator, and chain transfer agent is generally used. Examples of the organic solvent include ketone solvents, ether solvents, aprotic polar solvents, ester solvents, aromatic solvents, and chain or cyclic aliphatic solvents. Examples of the ketone solvent include methyl ethyl ketone and acetone. Examples of the ether solvent include dialkyl ethers such as methoxydimethyl ether (methylal) and diethyl ether; cyclic ethers such as tetrahydrofuran and 1,4-dioxane. Examples of the aprotic polar solvent include dimethylformamide and dimethyl sulfoxide. Examples of the ester solvent include alkyl acetates such as ethyl acetate and methyl acetate. Examples of the aromatic solvent include alkyl group-containing aromatic hydrocarbon solvents such as toluene and xylene; halogenated aromatic hydrocarbon solvents such as chlorobenzene and the like. Examples of the aliphatic solvent include chain aliphatic solvents such as hexane; cycloaliphatic solvents such as cyclohexane.

  The polymerization temperature is generally 20 ° C to 120 ° C, preferably 50 ° C to 110 ° C, more preferably 60 ° C to 100 ° C. Although polymerization may be performed even in a normal air atmosphere, polymerization in an inert gas atmosphere such as nitrogen or argon is preferable. The molecular weight of the obtained [A] polymer can be adjusted by controlling the ratio between the monomer amount and the chain transfer agent amount. The polymerization time is generally 0.5 hours to 144 hours, preferably 1 hour to 72 hours, more preferably 2 hours to 24 hours.

  [A] The polymer may have a residue derived from a chain transfer agent at the end of the molecular chain, may not have a residue derived from the chain transfer agent at the end of the molecular chain, It may be in a state in which a part of the residue derived from the chain transfer agent remains.

  The [A] polymer and other polymers used in the radiation-sensitive resin composition are naturally low in impurities such as halogen and metal, and the residual monomer and oligomer components are below a predetermined value, for example, It is preferably 0.1% by mass or less by HPLC analysis, thereby not only can further improve the sensitivity, resolution, process stability, pattern shape, etc. as a resist, but also change over time such as foreign matter in liquid and sensitivity. A radiation sensitive resin composition that can be used as a small amount of resist is obtained.

  Examples of the method for purifying the polymer include the following methods. Methods for removing impurities such as metals include chelating the metals by adsorbing the metals in the polymer solution using a zeta potential filter or by washing the polymer solution with an acidic aqueous solution such as oxalic acid or sulfonic acid. And the like. In addition, as a method of removing residual monomer and oligomer components below the specified value, a liquid-liquid extraction method that removes residual monomers and oligomer components by combining water washing and an appropriate solvent, those having a specific molecular weight or less Purification method in the state of solution such as ultrafiltration that extracts only, and reprecipitation to remove residual monomers by coagulating the polymer in the poor solvent by dropping the polymer solution into the poor solvent Examples thereof include a purification method in a solid state such as washing with a solvent or a poor solvent. Moreover, these methods can also be combined. The poor solvent used in the reprecipitation method depends on the physical properties of the polymer to be purified and cannot be generally exemplified, but those skilled in the art can appropriately select it according to the physical properties of the polymer. it can.

  [A] The weight average molecular weight in terms of polystyrene (hereinafter also referred to as “Mw”) by gel permeation chromatography (GPC) of the polymer is usually 1,000 to 300,000, preferably 2,000 to 300,000. More preferably, it is 2,000-20,000. [A] When the Mw of the polymer is less than 1,000, the heat resistance as a resist tends to decrease, and when it exceeds 300,000, the developability as a resist tends to decrease.

  [A] The ratio (Mw / Mn) between the polymer Mw and the polystyrene-equivalent number average molecular weight (hereinafter also referred to as “Mn”) by gel permeation chromatography (GPC) is preferably 1 to 5, and Preferably it is 1-3, Most preferably, it is 1-1.6.

<[B] Compound>
The said radiation sensitive resin composition contains the [B] compound represented by the said Formula (2) for controlling the spreading | diffusion of an acid in addition to a [A] polymer. The compound [B] acts as a base for the acid generated in the exposure process, but decomposes upon irradiation with actinic rays or radiation to lose basicity. Therefore, according to the said radiation sensitive resin composition containing a [B] compound, since an acid diffuses in an exposed part and acid diffusion in an unexposed part is controlled, favorable contrast is obtained.

In said formula (2), Y is a hydrogen atom, a hydroxyl group, an acryloyl group, or a methacryloyl group. R ³ is a divalent hydrocarbon group having 1 to 20 carbon atoms or —R—Z—R′—. R and R ′ are each independently a divalent hydrocarbon group having 1 to 20 carbon atoms. Z is —O—, —CO—, —COO—, —OCO—, —NH—, —NHCO— or —CONH—. However, R and R ′ may be bonded to each other to form a ring structure together with Z. X ^{- is, -O -, -COO -, -SO} 3 - or ^-N - "is .R" _-SO 2 -R is a monovalent hydrocarbon group having 1 to 20 carbon atoms, the hydrocarbon Part or all of the hydrogen atoms of the hydrogen group may be substituted with fluorine atoms. Q ⁺ is an onium cation.

Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms represented by R ³ , R and R ′ include chains such as a methylene group, an ethylene group, an n-propylene group, an n-butylene group and an n-pentylene group. An alicyclic hydrocarbon group obtained by removing two hydrogen atoms from an alicyclic hydrocarbon such as cyclopentane, cyclohexane, dicyclopentane, tricyclodecane, tetracyclododecane, norbornane, adamantane; A divalent hydrocarbon group partially containing a cyclic hydrocarbon group; an aromatic hydrocarbon group such as a phenylene group, a naphthylene group or a biphenylene group; a divalent hydrocarbon group partially containing the above aromatic hydrocarbon group Etc. In these hydrocarbon groups, some or all of the hydrogen atoms may be substituted with fluorine atoms. However, X ^- is -SO ₃ ^- if it is, SO ₃ ^- compounds in which the carbon atom bond is replaced by a fluorine atom or a perfluoroalkyl group and groups are not preferred.

  Examples of the ring structure formed by combining R and R ′ together with Z include, for example, when Z is —O—, monocyclic ether structure, polycyclic ether structure, etc .; when Z is —CO—, A cyclic ketone structure, a polycyclic ketone structure, and the like; when Z is —COO—, a monocyclic lactone structure, a polycyclic lactone, and the like can be given. Among these, a polycyclic ketone structure and a polycyclic lactone structure are preferable, a norbornanone structure and a norbornane lactone structure are more preferable, and a norbornanone structure is more preferable.

As the onium cation represented by Q ⁺ , as in the case of the onium cation represented by M ⁺ in the [A] polymer, the onium cation (sulfonium cation) represented by the above formula (3) and the above formula (4). It is preferable that it is at least 1 sort (s) of onium cation chosen from the group which consists of onium cations (iodonium cation) represented by these. Among these, an onium cation (sulfonium cation) represented by the above formula (3) is preferable, and a triphenylsulfonium cation is more preferable.

  [B] The compound is preferably at least one selected from the group consisting of compounds represented by the above formulas (2-1) to (2-6).

In the above formulas (2-1) to (2-6), R ⁶ is a monovalent chain hydrocarbon group having 1 to 6 carbon atoms. R ⁷ is each independently a divalent chain hydrocarbon group having 1 to 6 carbon atoms. The definition of Q ⁺ is the same as the above formula (2).

Examples of the monovalent chain hydrocarbon group represented by R ⁶ 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, n-pentyl group, n-hexyl group and the like. Among these, an n-butyl group, an n-pentyl group, and an n-hexyl group are preferable, and an n-butyl group is more preferable.

Examples of the divalent chain hydrocarbon group represented by R ⁷ include a methylene group, an ethylene group, an n-propylene group, an i-propylene group, an n-butylene group, and an n-pentylene group. Among these, an ethylene group, an n-propylene group and an i-propylene group are preferable, and an ethylene group is more preferable.

  Among the compounds represented by the above formulas (2-1) to (2-6), compounds represented by the formulas (2-1), (2-2), (2-3) and (2-4) Are preferable, and the compound represented by Formula (2-1) is more preferable.

  [B] The content of the compound is preferably 0.1 to 20 parts by mass, more preferably 100 parts by mass of the polymer [A], from the viewpoint of ensuring the sensitivity and developability as a resist. Is 0.5 to 10 parts by mass. By using at this content, the effect of improving the LWR can be sufficiently obtained, and a highly sensitive radiation-sensitive resin composition can be obtained.

<Optional component>
The radiation-sensitive resin composition contains, as an optional component, [C] a radiation-sensitive acid generator, [D] acid diffusion controller, [E] solvent, [F] additive, and the like. Also good.

<[C] Radiation sensitive acid generator>
The radiation-sensitive resin composition includes a [C] radiation-sensitive acid generator (hereinafter also referred to as “[C] acid generator”) other than the [A] component and the [B] component, as necessary. You may contain.

  Examples of the [C] acid generator include onium salts such as sulfonium salts and iodonium salts, organic halogen compounds, and sulfone compounds such as disulfones and diazomethane sulfones.

  Preferred examples of the [C] acid generator include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, triphenylsulfonium 2-bicyclo [ 2.2.1] triphenylsulfonium salt compounds such as hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate;

  4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-cyclohexylphenyldiphenylsulfonium 2-bicyclo [2. 2.1] 4-cyclohexylphenyldiphenylsulfonium salt compounds such as hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate;

  4-methanesulfonylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium 2- 4-methanesulfonylphenyldiphenylsulfonium salt compounds such as bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate;

  Diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2, Diphenyliodonium salt compounds such as 2-tetrafluoroethanesulfonate;

  Bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, Bis (4-t-butylphenyl) iodonium bis (4-t-butylphenyl) iodonium such as 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate Salt compounds;

  1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, (4-n-Butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium 2-bicyclo [2.2. 1] 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium salt compounds such as hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate;

  1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, (6-n-Butoxynaphthalen-2-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium 2-bicyclo [2.2. 1] 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium salt compounds such as hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate;

  1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, (3,5-Dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [2.2. 1] 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium salt compounds such as hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate;

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, N- (perfluoro-n-octanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- ( 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboxy imide, N- (2- (3- tetracyclo ^[4.4.0.1 2,5 ^{.1 7,10]} dodecanyl) -1,1-difluoroethane-sulfonyloxy) bicyclo [2.2.1] hept Bicyclo [2.2.1] such as -5-ene-2,3-dicarboximide, N- (camphorsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide. And hept-5-ene-2,3-dicarboximide compounds.

  [C] Acid generators can be used alone or in admixture of two or more. [C] The content of the acid generator is preferably 30 parts by mass or less with respect to 100 parts by mass of the polymer [A] from the viewpoint of ensuring sensitivity and developability as a resist. More preferably, it is 20 parts by mass. [C] The radiation sensitive resin composition which is excellent in transparency with respect to a radiation can be obtained as content of an acid generator is 30 mass parts or less.

<[D] Acid diffusion controller>
The radiation-sensitive resin composition may contain a [D] acid diffusion controller (excluding the [B] compound). Since the [B] compound contained in the radiation-sensitive resin composition has acid diffusion controllability, good resolution, pattern shape, and LWR characteristics can be obtained without using any other acid diffusion controller. However, [D] acid diffusion controller may be used. [D] A nitrogen-containing compound is preferably used as the acid diffusion controller.

  Examples of the nitrogen-containing compound include a compound represented by the following formula (6) (hereinafter also referred to as “nitrogen-containing compound (I)”), a compound having two nitrogen atoms in the same molecule (hereinafter, “ Nitrogen-containing compound (II) "), a polyamino compound having three or more nitrogen atoms in the same molecule and a polymer of a nitrogen atom-containing polymerizable compound (hereinafter collectively referred to as" nitrogen-containing compound (III) ") ), Amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

In the above formula (6), R ^15a , R ^15b and R ^15c are each independently a hydrogen atom, a linear or branched alkyl group which may be substituted, a cycloalkyl group, an aryl group or an aralkyl group. It is.

  Examples of the nitrogen-containing compound (I) include mono (cyclo) alkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, cyclohexylamine; di-n- Butylamine, di-n-pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine, cyclohexylmethylamine, dicyclohexylamine, etc. Di (cyclo) alkylamines; triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine , Tri-n-nonylamine, tri-n-decylamine, cyclohexyl Tri (cyclo) alkylamines such as dimethylamine, methyldicyclohexylamine and tricyclohexylamine; substituted alkylamines such as 2,2 ′, 2 ″ -nitrotriethanol; aniline, N-methylaniline, N, N-dimethylaniline 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, naphthylamine, 2,4,6-tri-tert-butyl-N-methylaniline, N-phenyldiethanolamine And aromatic amines such as 2,6-diisopropylaniline.

  Examples of the nitrogen-containing compound (II) include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diaminodiphenylmethane, and 4,4′-diaminodiphenylether. 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-methyl ester 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.

  Examples of the nitrogen-containing compound (III) include polyethyleneimine, polyallylamine, 2-dimethylaminoethylacrylamide polymer, and the like.

  Examples of the amide group-containing compound include Nt-butoxycarbonyldi-n-octylamine, Nt-butoxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt- Butoxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, Nt-butoxycarbonyl-N-methyl-1-adamantylamine, (S)-( -)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxycarbonyl-4-hydroxypiperidine Nt-butoxycarbonylpyrrolidine, Nt-butoxycarbonyl Perazine, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-butoxycarbonyl-N-methyl-1-adamantylamine, Nt-butoxycarbonyl-4,4′- Diaminodiphenylmethane, N, N′-di-t-butoxycarbonylhexamethylenediamine, N, N, N′N′-tetra-t-butoxycarbonylhexamethylenediamine,

  N, N′-di-t-butoxycarbonyl-1,7-diaminoheptane, N, N′-di-t-butoxycarbonyl-1,8-diaminooctane, N, N′-di-t-butoxycarbonyl- 1,9-diaminononane, N, N′-di-t-butoxycarbonyl-1,10-diaminodecane, N, N′-di-t-butoxycarbonyl-1,12-diaminododecane, N, N′-di -T-butoxycarbonyl-4,4'-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenzimidazole, N In addition to Nt-butoxycarbonyl group-containing amino compounds such as -t-butoxycarbonylpyrrolidine, 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.

  Examples of urea compounds include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tri-n-butylthiourea. Etc.

  Examples of the nitrogen-containing heterocyclic compound include imidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, benzimidazole, 2-phenylbenzimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2- Imidazoles such as methyl-1H-imidazole; pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, 2-methyl-4-phenylpyridine , Nicotine, nicotinic acid, nicotinamide, quinoline, 4-hydroxyquinoline, 8-oxyquinoline, acridine, pyridines such as 2,2 ′: 6 ′, 2 ″ -terpyridine; piperazine, 1- (2-hydroxyethyl ) In addition to piperazines such as piperazine, Gin, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, piperidine ethanol, 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 and the like can be mentioned.

  [D] The content of the acid diffusion controller is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, with respect to 100 parts by mass of the polymer (A), and 5 parts by mass or less. It is particularly preferred that By using it by the said content, while being excellent in the sensitivity and the developability of an exposure area | region, the radiation sensitive resin composition which is excellent in a pattern shape and a dimensional fidelity can be obtained.

<[E] solvent>
The radiation-sensitive resin composition usually contains an [E] solvent. The solvent used for the preparation of the radiation sensitive resin composition is not particularly limited as long as it can dissolve or disperse the polymer [A], the compound [B] and the optional component. For example,
Linear or branched ketones such as 2-pentanone, 2-hexanone, 2-heptanone, 2-octanone;
Cyclic ketones such as cyclopentanone and cyclohexanone;
Propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate;
Ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate and ethylene glycol monoethyl ether acetate;
Propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether and propylene glycol monoethyl ether;
Ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether;
Diethylene glycol dialkyl ethers such as diethylene glycol dimethyl ether and diethylene glycol diethyl ether;
Alkyl 2-hydroxypropionates such as methyl 2-hydroxypropionate and ethyl 2-hydroxypropionate;
Alkyl 3-alkoxypropionates such as methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate;
Esters such as n-butyl acetate, methyl pyruvate, ethyl pyruvate;
Lactams such as N-methylpyrrolidone:
Examples include lactones such as γ-butyrolactone.

  [E] 1 type (s) or 2 or more types can be used for a solvent. Among them, from propylene glycol monoalkyl ether acetates, propylene glycol monoalkyl ethers, linear, branched or cyclic ketones, alkyl 2-hydroxypropionate, alkyl 3-alkoxypropionate and lactones Preferably, at least one selected from the group consisting of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, 2-heptanone, cyclohexanone, ethyl 2-hydroxypropionate, ethyl 3-ethoxypropionate and γ-butyrolactone is used. It is more preferable to use at least one selected from the group, and it is selected from the group consisting of propylene glycol monomethyl ether acetate, cyclohexanone and γ-butyrolactone. It is more preferable to use at least one kind.

<[F] additive>
The radiation-sensitive resin composition may contain, for example, an alicyclic additive, a surfactant, a sensitizer, and the like as the [F] additive.

[Alicyclic additives]
An alicyclic additive is a component that exhibits an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like. The alicyclic additive may have an acid dissociable group.

  Examples of the alicyclic additives include 1-adamantanecarboxylic acid t-butyl, 1-adamantanecarboxylic acid t-butoxycarbonylmethyl, 1-adamantanecarboxylic acid α-butyrolactone ester, 1,3-adamantane dicarboxylic acid di-t. -Butyl, 1-adamantane acetate t-butyl, 1-adamantane acetate t-butoxycarbonylmethyl, 1,3-adamantanediacetate di-t-butyl, 2,5-dimethyl-2,5-di (adamantylcarbonyloxy) Adamantane derivatives such as hexane;

  Deoxycholate t-butyl, deoxycholate t-butoxycarbonylmethyl, deoxycholate 2-ethoxyethyl, deoxycholate 2-cyclohexyloxyethyl, deoxycholate 3-oxocyclohexyl, deoxycholate tetrahydropyranyl, deoxychol Deoxycholic acid esters such as acid mevalonolactone ester; t-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid, 2-cyclohexyloxyethyl lithocholic acid, 3-oxocyclohexyl lithocholic acid, lithocholic acid Lithocholic acid esters such as tetrahydropyranyl acid, lithocholic acid mevalonolactone ester; dimethyl adipate, diethyl adipate, dipropyl adipate, di-n-adipate Chill, and the like alkyl carboxylic acid esters such as adipate t- butyl. In addition, the said alicyclic additive can use 1 type (s) or 2 or more types.

[Surfactant]
A surfactant is a component that exhibits an effect of improving coating properties, striation, developability, and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene In addition to nonionic surfactants such as glycol distearate, the following are all trade names: KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (manufactured by Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (manufactured by Tochem Products), Megafuck F171, F173 (manufactured by Dainippon Ink and Chemicals), Florard FC430, FC431 (Sumitomo 3M) Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (made by Asahi Glass Co., Ltd.), etc. Can do. The said surfactant can use 1 type (s) or 2 or more types. As a compounding quantity of surfactant, it is preferable that it is 2 mass parts or less with respect to 100 mass parts of [A] polymers.

[Sensitizer]
The sensitizer absorbs the energy of radiation and transmits the energy to the photoacid generator, thereby increasing the amount of acid generated, improving the apparent sensitivity of the radiation-sensitive resin composition. It has the effect to make it. Examples of the sensitizer include carbazoles, benzophenones, rose bengals, anthracenes, phenols and the like. The said sensitizer can use 1 type (s) or 2 or more types. As a compounding quantity of a sensitizer, it is preferable that it is 50 mass parts or less with respect to 100 mass parts of [A] polymers.

<Method for preparing radiation-sensitive resin composition>
The radiation-sensitive resin composition usually has a total solid content concentration (ratio of the total mass of components other than the solvent [E] to the composition) of 1 to 50% by mass, preferably 3 to 25% by mass. [E] After being dissolved in the solvent, for example, it is filtered through a filter having a pore size of about 0.2 μm to prepare a radiation-sensitive resin composition solution.

  Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Each physical property measurement in each of the following synthesis examples was performed by the following method.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
For Synthesis Examples 1 to 7, 12, and 13, using GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL) manufactured by Tosoh Corporation, with a flow rate of 1.0 mL / minute, tetrahydrofuran as an elution solvent, and an analysis condition with a column temperature of 40 ° C. Measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard.
For Synthesis Examples 8 to 11, GPC columns manufactured by Tosoh Corporation (TSKgel α-2500, TSKgel α-M) were used as GPC columns, the flow rate was 1.0 mL / min, and LiBr was 30 mmol / L and H ₃ as the elution solvent. Gel permeation using MALLS (manufactured by Wyatt, DAWN DSP, cell type K5, laser wavelength 632.8 nm) as a detector using dimethylformamide in which PO ₄ is dissolved at 10 mmol / L under analysis conditions at a column temperature of 40 ° C. It was measured by chromatography (GPC).

[ ¹³ C-NMR analysis]
It measured using "JNM-EX270" by JEOL.

<[A] Synthesis of polymer>
[A] Each monomer used for the synthesis of the polymer is shown below.

[Synthesis Example 1]
19.30 g (46 mol%) of the monomer (M-1), 5.12 g (4 mol%) of the monomer (M-7) and 25.58 g (50 mol%) of the monomer (M-5) ) Was dissolved in 100 g of 2-butanone, and 1.89 g of 2,2′-azobis (isobutyronitrile) (AIBN) (5 mol% based on the total number of moles of monomers) was further dissolved. A solution was prepared. On the other hand, a 300 mL three-necked flask charged with 50 g of 2-butanone was purged with nitrogen for 30 minutes, and then the reaction kettle was heated to 80 ° C. with stirring, and the monomer solution prepared in advance was added using a dropping funnel. The solution was added dropwise over 3 hours. The polymerization start was carried out for 6 hours with the start of dropping as the polymerization start time. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or lower, poured into 1,000 g of methanol, and the precipitated white powder was separated by filtration. The filtered white powder was washed with 200 g of methanol twice as a slurry, then filtered and dried at 50 ° C. for 17 hours to obtain a white powder polymer (A-1) ( 36.3 g, yield 72.5%). This polymer (A-1) has an Mw of 6,800 and an Mw / Mn (molecular weight dispersity) of 1.35. As a result of ¹³ C-NMR analysis, the structure derived from the monomer (M-7) Unit: a copolymer having a structural unit derived from the monomer (M-1): a content ratio (molar ratio) of the structural unit derived from the monomer (M-5) of 4.0: 45.8: 50.2 Met. Moreover, as a result of measuring the content rate of the low molecular weight component of molecular weight less than 1,000 of the obtained polymer (A-1) by GPC, it was less than 0.1 mol%.

[Synthesis Examples 2, 4, 5, 6, 8, 9, 10, 11 and 12]
In Synthesis Example 1, polymers (A-2), (A-4), and (A-5) were respectively obtained in the same manner as in Synthesis Example 1 except that the types and amounts of monomers shown in Table 1 below were used. ), (A-6), (A-8), (A-9), (A-10), (A-11) and (a-1). Table 2 shows the measurement results of the yield (%) of the obtained polymer, Mw, Mw / Mn, and the content ratio (mol%) of each structural unit in each polymer.

[Synthesis Examples 3, 7, and 13]
In Synthesis Example 1, the same manner as in Synthesis Example 1 was used, except that the type and amount of the monomers shown in Table 1 below were used and the monomer (M-3) was added to the three-necked flask before polymerization. Thus, polymers (A-3), (A-7) and (A-9) were obtained. Table 2 shows the measurement results of the yield (%) of the obtained polymer, Mw, Mw / Mn, and the content ratio (mol%) of each structural unit in each polymer.

<Preparation of radiation-sensitive resin composition>
The [B] compound, [C] radiation sensitive acid generator, [D] acid diffusion inhibitor and [E] solvent used for the preparation of the radiation sensitive resin composition are shown below.

[[B] Compound]
Compounds represented by the following formulas (B-1) to (B-5), respectively

[[C] Radiation sensitive acid generator]
C-1: Triphenylsulfonium nonafluoro-n-butanesulfonate

[[D] acid diffusion controller]
D-1: Nt-butoxycarbonyl-4-hydroxypiperidine D-2: tri-n-octylamine

[[E] solvent]
E-1: Propylene glycol monomethyl ether acetate E-2: Cyclohexanone E-3: γ-butyrolactone

[Example 1]
100 parts by mass of polymer (A-1), 7 parts by mass of compound (B-1), 1,700 parts by mass of solvent (E-1), 700 parts by mass of (E-2) and 30 parts by mass of (E-3) The radiation-sensitive resin composition of Example 1 was prepared by mixing the parts and filtering the resulting liquid mixture with a membrane filter having a pore size of 200 nm.

[Examples 2 to 16 and Comparative Examples 1 to 4]
In Example 1, the radiation sensitive resin compositions of Examples 2 to 16 and Comparative Examples 1 to 4 were the same as Example 1 except that the types and amounts of each component were as shown in Table 3 below. Prepared. “-” Indicates that the component was not used.

<Evaluation of radiation-sensitive resin composition (1)>
About each radiation sensitive resin composition of Examples 1-11 and Comparative Examples 1-3, evaluation about a sensitivity, a pattern shape, and LWR was performed with the following method. These evaluation results are shown in Table 4.

[sensitivity]
Using a silicon wafer having an ARC66 (Nissan Chemical Industries) film with a thickness of 1,050 mm formed on the wafer surface, each composition solution was applied onto the substrate by spin coating using a clean track ACT12 (manufactured by Tokyo Electron). On the hot plate, pre-baking (PB) was performed for 60 seconds at the temperature shown in Table 4 to form a resist film having a thickness of 0.09 μm. After that, using Lithius Pro-i (manufactured by Tokyo Electron) on the resist film, TCX041 (manufactured by JSR) is applied by spin coating, and PB is performed on a hot plate at 90 ° C. to form a 0.09 μm thick top coat film did. The film formed as described above was exposed through a mask pattern using a Nikon ArF excimer laser exposure apparatus “S610C” (numerical aperture 1.30). After performing PEB at the temperature shown in Table 4 for 60 seconds, developing with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C. for 60 seconds, washing with water, and drying to form a positive resist pattern did. At this time, the optimum exposure dose is defined as an exposure dose such that a pattern obtained through a mask for obtaining a 0.044 μm diameter line and space pattern (1L1S) has a diameter of 0.044 μm. (Unit: mJ / cm ² ) was defined as sensitivity.

[Pattern shape (pattern cross-sectional shape)]
The cross-sectional shape of the 0.044 μm line and space pattern obtained in the above-described sensitivity measurement was observed with “S-4800” manufactured by Hitachi High-Technologies Corporation, and the pattern shape was evaluated. The case of showing a rectangular shape was evaluated as “A” (good), and the case of showing a shape other than a rectangle was evaluated as “B” (defective).

[LWR (line width roughness)]
At the optimum exposure amount, a 0.044 μm (1L1S) pattern formed on the resist film on the substrate is observed from the upper part of the pattern using a length measuring SEM (manufactured by Hitachi, Ltd., model number “CG4000”), and the pattern width Was measured at an arbitrary point, and the variation of the measured value was determined as 3 sigma, which was defined as LWR (unit: nm). The LWR is preferably as small as possible, and the case of 3.0 nm or less was evaluated as “A” (good), and the case of exceeding 3.0 nm was evaluated as “B” (bad).

  From the results of Table 4, the radiation sensitive resin compositions of Examples 1 to 11 have a small LWR and a rectangular cross section in ArF exposure as compared with the radiation sensitive resin compositions of Comparative Examples 1 to 3. It was shown that a resist pattern having an excellent pattern shape can be formed.

<Evaluation of radiation sensitive resin composition (2)>
About each radiation sensitive resin composition of Examples 12-16 and the comparative example 4, evaluation about the sensitivity, nano edge roughness, and the resolution was performed with the following method. These evaluation results are shown in Table 5.

[sensitivity]
In “Clean Track ACT-8” manufactured by Tokyo Electron, a radiation sensitive resin composition was spin coated on a silicon wafer, and then PB was performed for 90 seconds at the temperature shown in Table 5 to form a resist film having a film thickness of 60 nm. did. Thereafter, the resist film formed above was irradiated with an electron beam using a simple electron beam drawing apparatus (manufactured by Hitachi, Ltd., model “HL800D”, output: 50 KeV, current density: 5.0 amperes / cm ² ). After the electron beam irradiation, PEB was performed for 90 seconds at the temperature shown in Table 5. Thereafter, a 2.38 mass% tetramethylammonium hydroxide aqueous solution was used and developed by the paddle method at 23 ° C. for 1 minute, followed by washing with pure water and drying to form a resist pattern. At this time, a line-and-space pattern (1L1S) composed of a line portion having a line width of 150 nm and a space portion (that is, a groove) having an interval of 150 nm formed by adjacent line portions is formed in a one-to-one line width. The exposure amount was taken as the optimum exposure amount, and this optimum exposure amount was taken as the sensitivity (unit: μC / cm ² ).

[Nano edge roughness]
A line-and-space pattern (1L1S) line pattern having a design line width of 150 nm was observed with a semiconductor scanning electron microscope (high resolution FEB length measuring device, trade name “S-9220”, manufactured by Hitachi, Ltd.). With respect to the observed shape, as shown in FIG. 1 and FIG. 2, the line width and the design line at the most conspicuous portion of the unevenness generated along the lateral surface 2 a of the line portion 2 of the resist film formed on the silicon wafer 1. The nano edge roughness (unit: nm) was calculated from the difference “ΔCD” from the width of 150 nm.

[resolution]
For the line-and-space pattern (1L1S), the minimum line width of the line pattern resolved with the optimum exposure dose was taken as the resolution (unit: nm).

  From the results of Table 5, the radiation sensitive resin compositions of Examples 12 to 16 are more sensitive to electron beams, have a smaller nano edge roughness, and have a higher resolution than the radiation sensitive resin composition of Comparative Example 1. It was also shown that an excellent resist pattern can be formed.

  As described above, as shown from the results of Tables 4 and 5, according to the radiation-sensitive resin composition of the present invention, in both cases of ultraviolet rays such as ArF and charged particle beams such as electron beams, LWR and nano It can be said that the edge roughness is suppressed, a resist pattern having a good rectangular pattern shape and excellent resolution can be formed.

  According to the radiation sensitive resin composition of the present invention, it is possible to form a resist pattern having a small LWR and an excellent pattern shape. Therefore, the radiation sensitive resin composition of the present invention is useful as a material capable of forming a chemically amplified resist for manufacturing semiconductor devices, which is expected to be further miniaturized in the future.

1 base material 2 resist pattern 2a lateral side of resist pattern

Claims (4)

[A] An acid-dissociable group-containing polymer having a structural unit (I) represented by the following formula (1), and [B] a radiation-sensitive resin composition containing a compound represented by the following formula (2) .

(In Formula (1), R ¹ is a hydrogen atom, a fluorine atom, a trifluoromethyl group, or an alkyl group having 1 to 3 carbon atoms. E is a single bond or —COO—. R ² is carbon. It is a divalent hydrocarbon group of 1 to 20, and some or all of the hydrogen atoms of this hydrocarbon group may be substituted with fluorine atoms, n is an integer of 0 to 5. M ⁺ Is an onium cation.)

(In Formula (2), Y is a hydrogen atom, a hydroxyl group, an acryloyl group, or a methacryloyl group. R ³ is a divalent hydrocarbon group having 1 to 20 carbon atoms or —R—Z—R′—. R and R ′ are each independently a divalent hydrocarbon group having 1 to 20 carbon atoms, Z is —O—, —CO—, —COO—, —OCO—, —NH—. , —NHCO— or —CONH—, wherein R and R ′ may be bonded to each other to form a ring structure with Z. X ⁻ represents —O ⁻ , —COO ⁻ , —SO. ₃ ^- or ^-N - "is .R a" is _-SO 2 -R, a monovalent hydrocarbon group having 1 to 20 carbon atoms, in some or all of the fluorine atoms of the hydrogen atoms of the hydrocarbon group Optionally substituted, Q ⁺ is an onium cation.) The radiation sensitive according to claim 1, wherein M ⁺ in the formula (1) is at least one onium cation selected from the group consisting of onium cations represented by the following formula (3) and the following formula (4), respectively. Resin composition.

(In formula (3), R ^4a , R ^4b and R ^4c are each independently a monovalent hydrocarbon group having 1 to 30 carbon atoms or a monovalent heterocyclic group having 4 to 30 carbon atoms. However, part or all of the hydrogen atoms of the hydrocarbon group and heterocyclic group may be substituted, and any two of R ^4a , R ^4b and R ^4c are bonded to each other, and (A cyclic structure may be formed with the sulfur atom to be bonded.)

(In Formula (4), R ^5a and R ^5b are each independently a monovalent hydrocarbon group having 1 to 30 carbon atoms or a monovalent heterocyclic group having 4 to 30 nucleus atoms, provided that Some or all of the hydrogen atoms of the hydrocarbon group and heterocyclic group may be substituted, and R ^5a and R ^5b are bonded to each other to form a cyclic structure together with the iodine atom to which they are bonded. May be.) The radiation sensitive resin composition according to claim 1, wherein the compound [B] is at least one compound selected from the group consisting of compounds represented by the following formulas (2-1) to (2-6). .

(In formulas (2-1) to (2-6), R ⁶ is a monovalent chain hydrocarbon group having 1 to 6 carbon atoms. R ⁷ is independently from 1 to 6 carbon atoms. (The definition of Q ⁺ is the same as in the above formula (2).) [A] The radiation sensitive resin composition according to claim 1, wherein the polymer further has a structural unit (II) represented by the following formula (5).

(In the formula (5), ^.R 8, ^{R 9} and ^{R 10} defined is the same as the above formula (1) of ^{R 1} are each independently 4 alkyl group or a carbon number of 1 to 4 carbon atoms (However, R ⁹ and R ¹⁰ may be bonded to each other to form a cycloalkanediyl group having 4 to 20 carbon atoms together with the carbon atom to which they are bonded.)

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