JP2012078405A - Radiation-sensitive resin composition, pattern forming method and compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation-sensitive resin composition not only having sufficient basic characteristics such as sensitivity and resolution but having sufficient MEEF (mask error enhancement factor) performance.SOLUTION: The radiation-sensitive resin composition contains: [A] an acid generator expressed by formula (1); and [B] (b1) a polymer having a structural unit the solubility of which with an alkali developing solution is increased by an action of an acid. In formula (1), Rrepresents a monovalent organic group; Y represents a divalent organic group having 1 to 15 carbon atoms, in which a part or whole of hydrogen atoms possessed by the divalent organic group having 1 to 15 carbon atoms may be substituted; and Arepresents an organic cation.

Description

  The present invention relates to a radiation-sensitive resin composition, a pattern formation method using the same, and a compound.

  In the field of microfabrication for manufacturing integrated circuit elements, etc., lithography using radiation with shorter wavelengths such as KrF excimer laser (wavelength 248 nm) and ArF excimer laser (wavelength 193 nm) in order to obtain a higher degree of integration. Technology is being developed. As a material for a photoresist film for excimer laser, a chemically amplified resist containing a component having an acid dissociable group and an acid generator that generates an acid upon irradiation with radiation is generally used.

  On the other hand, in the same microfabrication field, it is desired to form a finer resist pattern having a line width of about 45 nm, and an immersion exposure method is known as a method for forming such a resist pattern. According to the immersion exposure method, since a lens and an exposure light source mounted on an existing apparatus can be used, the cost is excellent. In addition, when the immersion exposure method is used, a resist pattern having excellent resolution and the like can be formed as in the case where the light source wavelength of the exposure apparatus is shortened. A radiation sensitive resin composition used for such an immersion exposure method has been developed (see Patent Documents 1 to 3). Furthermore, as a radiation-sensitive acid generator contained in the radiation-sensitive resin composition, sulfonium salts having various functional groups have been developed (see Patent Document 4).

  However, in recent years when further device miniaturization is progressing, the conventional radiation-sensitive resin composition has not only improved basic characteristics such as sensitivity, resolution, and pattern rectangularity. Other performances are also required. Specific other performance includes reduction of MEEF (Mask Error Enhancement Factor), which is an index representing the mask error tolerance.

International Publication No. 2004/068242 JP 2005-173474 A JP 2006-48029 A Japanese Patent Laid-Open No. 03-148256

  The present invention has been made based on the above circumstances, and its purpose is to provide a radiation-sensitive resin composition that sufficiently satisfies not only basic characteristics such as sensitivity and resolution, but also MEEF performance. It is.

（式（１）中、Ｒ^１は１価の有機基である。Ｙは炭素数１〜１５の２価の有機基である。但し、炭素数１〜１５の２価の有機基が有する水素原子の一部又は全部は置換されていてもよい。Ａ^＋はカチオンである。） The invention made to solve the above problems is
[A] Acid generator represented by the following formula (1) (hereinafter sometimes referred to as “[A] acid generator”), and [B] (b1) Solubility in an alkaline developer by the action of the acid Having a structural unit (hereinafter, sometimes referred to as “(b1) structural unit”) in which is increased or decreased (hereinafter sometimes referred to as “[B] polymer”)
Is a radiation-sensitive resin composition.

(In Formula (1), R ¹ is a monovalent organic group. Y is a divalent organic group having 1 to 15 carbon atoms, provided that hydrogen contained in the divalent organic group having 1 to 15 carbon atoms. Some or all of the atoms may be substituted. A ⁺ is a cation.)

[A] The acid generator has the above specific structure (—OCOCH ₂ O—), so that it has an appropriate polarity and [B] a polymer having an acid dissociable group, thereby increasing the affinity of the acid generator. Diffusion is moderately controlled. Furthermore, the [A] acid generator is relatively easy to synthesize and is excellent in productivity. Therefore, by including the [A] acid generator excellent in productivity, the radiation-sensitive composition can sufficiently satisfy not only basic characteristics such as sensitivity and resolution but also MEEF performance.

（式（２）中、
Ｒ^１は酸素原子を含んでいてもよい炭素数１〜２０の脂肪族基である。但し、水素原子の一部又は全部が置換されていてもよい。
Ｙは硫黄原子と結合する末端炭素原子に少なくとも１つのフッ素原子が結合している炭素数１〜１０のアルカンジイル基である。
Ｒ^２及びＲ^３はそれぞれ独立して、炭素数１〜２０の鎖状脂肪族炭化水素基、炭素数６〜３０の芳香族炭化水素基、炭素数３〜２０の脂環式炭化水素基である。Ｒ^４はフェニル基又はナフチル基である。但し、これらのＲ^２、Ｒ^３及びＲ^４が示す基が有する水素原子の一部又は全部は、ハロゲン原子、ヒドロキシル基、シアノ基、アルコキシル基、炭素数１〜１０のアルキル基、アリール基、又はアラルキル基で置換されていてもよい。また、これらの置換基は骨格鎖中に−Ｏ−ＣＯ−、−ＣＯ−Ｏ−、−ＳＯ_２−、−ＳＯ_３−、−Ｏ−、−ＮＲ^５−ＣＯ−、−ＣＯ−ＮＲ^５−を含んでいてもよい。
Ｒ^５は炭素数１〜５のアルキル基、アリール基又はアラルキル基である。但し、これらの基が有する水素原子の一部又は全部はハロゲン原子で置換されていてもよい。） [A] The acid generator is preferably a compound represented by the following formula (2). [A] MEEF performance improves more by making an acid generator into the following specific structure.

(In the formula (2),
R ¹ is an aliphatic group having 1 to 20 carbon atoms which may contain an oxygen atom. However, some or all of the hydrogen atoms may be substituted.
Y is an alkanediyl group having 1 to 10 carbon atoms in which at least one fluorine atom is bonded to a terminal carbon atom bonded to a sulfur atom.
R ² and R ³ are each independently a chain aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, and an alicyclic hydrocarbon group having 3 to 20 carbon atoms. is there. R ⁴ is a phenyl group or a naphthyl group. However, some or all of the hydrogen atoms contained in the groups represented by R ² , R ³ and R ⁴ are a halogen atom, a hydroxyl group, a cyano group, an alkoxyl group, an alkyl group having 1 to 10 carbon atoms, an aryl group, Alternatively, it may be substituted with an aralkyl group. In addition, these substituents are included in the skeleton chain: —O—CO—, —CO—O—, —SO ₂ —, —SO ₃ —, —O—, —NR ⁵ —CO—, —CO—NR ⁵ —. May be included.
R ⁵ is an alkyl group having 1 to ⁵ carbon atoms, an aryl group, or an aralkyl group. However, some or all of the hydrogen atoms contained in these groups may be substituted with halogen atoms. )

  [B] The polymer preferably further has (b2) a structural unit having a lactone skeleton or a cyclic carbonate skeleton (hereinafter sometimes referred to as “(b2) structural unit”). [B] When the polymer further has the structural unit (b2), basic resist characteristics such as adhesion of the resist film to the substrate can be improved.

  [B] The polymer preferably further has (b3) a structural unit containing a polar group (hereinafter sometimes referred to as “(b3) structural unit”). When the [B] polymer further has the (b3) structural unit, the affinity between the [A] acid generator and the [B] polymer is further increased, and as a result, the MEEF performance can be improved.

  The radiation-sensitive resin composition preferably further contains a polymer having [C] fluorine atoms (hereinafter sometimes referred to as “[C] polymer”). When the radiation sensitive composition contains the [C] polymer, the hydrophobicity of the resist film is improved, and when the immersion exposure is performed, the substance elution is excellent, and the resist film and the immersion liquid The receding contact angle can be made sufficiently high, and there are effects such as no water droplets remaining when scanning exposure is performed at high speed, so that the usefulness of the radiation sensitive composition for immersion exposure is enhanced.

  The radiation-sensitive resin composition preferably further contains [D] a nitrogen-containing organic compound. The radiation-sensitive resin composition further contains a [D] nitrogen-containing compound, thereby controlling the diffusion phenomenon in the resist film of the acid generated from the [A] acid generator upon exposure, and undesirable chemistry in the non-exposed region. The effect of suppressing the reaction is exhibited, the resolution as a resist is further improved, and the storage stability of the resulting radiation-sensitive resin composition is improved.

The pattern forming method of the present invention comprises:
(I) applying the radiation-sensitive resin composition to a substrate to form a resist film;
(Ii) a step of exposing the resist film; and (iii) a step of alkali developing the exposed resist film.

  By the formation method, a resist pattern can be formed from the radiation-sensitive composition that sufficiently satisfies not only basic characteristics such as sensitivity and resolution but also MEEF performance.

（式（１）中、Ｒ^１は１価の有機基である。Ｙは炭素数１〜１５の２価の有機基である。但し、炭素数１〜１５の２価の有機基が有する水素原子の一部又は全部は置換されていてもよい。Ａ^＋はカチオンである。） The compound of the present invention is represented by the following formula (1).

(In Formula (1), R ¹ is a monovalent organic group. Y is a divalent organic group having 1 to 15 carbon atoms, provided that hydrogen contained in the divalent organic group having 1 to 15 carbon atoms. Some or all of the atoms may be substituted. A ⁺ is a cation.)

  The said compound can be used conveniently as a material of the said radiation sensitive composition, for example.

（式（２）中、
Ｒ^１は酸素原子を含んでいてもよい炭素数１〜２０の脂肪族基である。但し、水素原子の一部又は全部が置換されていてもよい。
Ｙは硫黄原子と結合する末端炭素原子に少なくとも１つのフッ素原子が結合している炭素数１〜１０のアルカンジイル基である。
Ｒ^２及びＲ^３はそれぞれ独立して、炭素数１〜２０の鎖状脂肪族炭化水素基、炭素数６〜３０の芳香族炭化水素基、炭素数３〜２０の脂環式炭化水素基である。但し、これらの基が有する水素原子の一部又は全部はハロゲン原子、ヒドロキシル基、シアノ基、アルコキシル基、炭素数１〜１０のアルキル基、アリール基、又はアラルキル基で置換されていてもよい。また、これらの置換基は骨格鎖中に−Ｏ−ＣＯ−、−ＣＯ−Ｏ−、−ＳＯ_２−、−ＳＯ_３−、−Ｏ−、−ＮＲ^５−ＣＯ−、−ＣＯ−ＮＲ^５−を含んでいてもよい。
Ｒ^５は炭素数１〜５のアルキル基、アリール基又はアラルキル基である。但し、これらの基が有する水素原子の一部又は全部はハロゲン原子で置換されていてもよい。
Ｒ^４はフェニル基又はナフチル基である。） The compound of the present invention is represented by the following formula (2).

(In the formula (2),
R ¹ is an aliphatic group having 1 to 20 carbon atoms which may contain an oxygen atom. However, some or all of the hydrogen atoms may be substituted.
Y is an alkanediyl group having 1 to 10 carbon atoms in which at least one fluorine atom is bonded to a terminal carbon atom bonded to a sulfur atom.
R ² and R ³ are each independently a chain aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, and an alicyclic hydrocarbon group having 3 to 20 carbon atoms. is there. However, some or all of the hydrogen atoms contained in these groups may be substituted with a halogen atom, a hydroxyl group, a cyano group, an alkoxyl group, an alkyl group having 1 to 10 carbon atoms, an aryl group, or an aralkyl group. In addition, these substituents are included in the skeleton chain: —O—CO—, —CO—O—, —SO ₂ —, —SO ₃ —, —O—, —NR ⁵ —CO—, —CO—NR ⁵ —. May be included.
R ⁵ is an alkyl group having 1 to ⁵ carbon atoms, an aryl group, or an aralkyl group. However, some or all of the hydrogen atoms contained in these groups may be substituted with halogen atoms.
R ⁴ is a phenyl group or a naphthyl group. )

  When the compound has the specific structure, for example, when used as a material of the radiation-sensitive composition, the effect of the radiation-sensitive composition can be further improved.

  The “radiation” of the “radiation-sensitive resin composition” in the present specification is a concept including visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams and the like.

  According to the present invention, a radiation-sensitive resin composition that sufficiently satisfies not only basic characteristics such as sensitivity and resolution, but also MEEF performance, a forming method for forming a resist pattern from the composition, and the composition A compound that can be suitably used as a material can be provided. In addition, the composition can be suitably used in an immersion exposure method or the like.

<Radiation sensitive resin composition>
The radiation sensitive resin composition of the present invention contains an [A] acid generator and a [B] polymer. Moreover, a [C] polymer, a [D] nitrogen-containing organic compound, and another arbitrary component can be contained as needed. Hereinafter, each component will be described in detail.

<[A] Acid generator>
The [A] acid generator contained in the radiation-sensitive resin composition is represented by the above formula (1). In the above formula (1), R ¹ is a monovalent organic group. Y is a C1-C15 divalent organic group. However, one part or all part of the hydrogen atom which a C1-C15 bivalent organic group has may be substituted. A ⁺ is a cation.

The monovalent organic group represented by R ¹ is preferably an aliphatic group having 1 to 20 carbon atoms which may contain an oxygen atom. However, some or all of the hydrogen atoms may be substituted. The aliphatic group having 1 to 20 carbon atoms which may contain an oxygen atom is preferably an alicyclic group having a lactone structure.

  Examples of the aliphatic group having 1 to 20 carbon atoms include chain aliphatic groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, and tert-butyl group; alkyl group, cyclobutyl Group, cyclopentyl group, cyclohexyl group, cyclooctyl group and other cycloalkyl groups; phenyl group, naphthyl group, anthracenyl group and other aryl groups; norbornyl group, tricyclodecanyl group, tetracyclododecanyl group, adamantyl group, etc. Examples thereof include bridged alicyclic hydrocarbon groups. Among these, an adamantyl group and an alicyclic group having 3 to 20 carbon atoms which may contain an oxygen atom are preferable, and a methyladamantyl group and a norbornane lactone group are more preferable.

  The divalent organic group having 1 to 15 carbon atoms represented by Y is preferably an alkanediyl group having 1 to 10 carbon atoms in which at least one fluorine atom is bonded to a terminal carbon atom bonded to a sulfur atom. Examples of the alkanediyl group having 1 to 10 carbon atoms include methanediyl group, ethanediyl group, propanediyl group, butanediyl group, pentanediyl group, hexanediyl and the like. Among these, an ethanediyl group, a propanediyl group, a butanediyl group, and a hexanediyl group are preferable, and an ethanediyl group and a butanediyl group are more preferable.

As A ⁺ in the above formula (1), a cation represented by the above formula (2) is preferable. In the above formula (2), R ² and R ³ are each independently a chain aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, and 3 to 20 carbon atoms. An alicyclic hydrocarbon group. R ⁴ is a phenyl group or a naphthyl group. However, some or all of the hydrogen atoms contained in the groups represented by R ² , R ³ and R ⁴ are a halogen atom, a hydroxyl group, a cyano group, an alkoxyl group, an alkyl group having 1 to 10 carbon atoms, an aryl group, Alternatively, it may be substituted with an aralkyl group. In addition, these substituents are included in the skeleton chain: —O—CO—, —CO—O—, —SO ₂ —, —SO ₃ —, —O—, —NR ⁵ —CO—, —CO—NR ⁵ —. May be included. R ⁵ is an alkyl group having 1 to ⁵ carbon atoms, an aryl group, or an aralkyl group. However, some or all of the hydrogen atoms contained in these groups may be substituted with halogen atoms.

  Examples of the chain aliphatic hydrocarbon group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. It is done.

  Examples of the aromatic hydrocarbon group having 6 to 30 carbon atoms include phenyl, naphthyl, and aromatics such as benzene, naphthalene, phenanthrene, anthracene, tetracene, pentacene, pyrene, picene, toluene, xylene, ethylbenzene, mesitylene, cumene, and the like. A group obtained by removing one hydrogen atom from a hydrocarbon is exemplified.

  Examples of the alicyclic hydrocarbon group having 3 to 20 carbon atoms include cycloalkyl groups such as cyclobutyl group, cyclopentyl group, cyclohexyl group, and cyclooctyl group; norbornyl group, tricyclodecanyl group, tetracyclododecanyl group, adamantyl group And a bridged alicyclic hydrocarbon group such as a group.

  Examples of the cation represented by the above formula (2) include triphenylsulfonium cation, tri-1-naphthylsulfonium cation, tri-tert-butylphenylsulfonium cation, 4-fluorophenyl-diphenylsulfonium cation, and di-4-fluorophenyl. -Phenylsulfonium cation, tri-4-fluorophenylsulfonium cation, 4-cyclohexylphenyl-diphenylsulfonium cation, 4-methanesulfonylphenyl-diphenylsulfonium cation, 4-cyclohexanesulfonyl-diphenylsulfonium cation, 1-naphthyldimethylsulfonium cation, 1 -Naphtyl diethylsulfonium cation, 1- (4-hydroxynaphthyl) dimethylsulfonium cation, 1- (4-methyl) Naphthyl) dimethylsulfonium cation, 1- (4-methylnaphthyl) diethylsulfonium cation, 1- (4-cyanonaphthyl) dimethylsulfonium cation, 1- (4-cyanonaphthyl) diethylsulfonium cation, 1- (3,5-dimethyl -4-hydroxyphenyl) tetrahydrothiophenium cation, 1- (4-methoxynaphthyl) tetrahydrothiophenium cation, 1- (4-ethoxynaphthyl) tetrahydrothiophenium cation, 1- (4-n-propoxynaphthyl) Tetrahydrothiophenium cation, 1- (4-n-butoxynaphthyl) tetrahydrothiophenium cation, 2- (7-methoxynaphthyl) tetrahydrothiophenium cation, 2- (7-ethoxynaphthyl) tetrahydrothi Fe cation, 2- (7-n- propoxy-naphthyl) tetrahydrothiophenium cation, 2- (7-n- butoxynaphthyl) tetrahydrothiophenium cation are preferred.

  [A] The acid generator can be composed of a combination of the above anions and cations. [A] An acid generator may be used independently and may be used in mixture of 2 or more types.

  The radiation sensitive resin composition may be used in combination with an acid generator other than the [A] acid generator. Examples of such [A] acid generators include onium salt compounds, halogen-containing compounds, diazoketone compounds, sulfone compounds, and sulfonic acid compounds. These other acid generators can be used alone or in admixture of two or more.

  Examples of onium salt compounds include iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like.

  Examples of the halogen-containing compound include haloalkyl group-containing hydrocarbon compounds and haloalkyl group-containing heterocyclic compounds.

  Examples of the diazoketone compound include a 1,3-diketo-2-diazo compound, a diazobenzoquinone compound, a diazonaphthoquinone compound, and the like.

  Examples of the sulfone compound include β-ketosulfone, β-sulfonylsulfone, α-diazo compounds of these compounds, and the like.

  Examples of the sulfonic acid compound include alkyl sulfonic acid esters, alkyl sulfonic acid imides, haloalkyl sulfonic acid esters, aryl sulfonic acid esters, and imino sulfonates.

  In the said radiation sensitive resin composition, as a usage-ratio of [A] acid generator, 1 mass part-20 mass parts are preferable with respect to 100 mass parts of [B] polymers, and 5 mass parts-15 mass parts. Is preferred. The use ratio of the other acid generator is preferably 99% by mass or less and more preferably 75% by mass or less with respect to all the acid generators used. [A] The total amount of the acid generator and the other acid generator used is usually 0.1 parts by mass with respect to 100 parts by mass of the polymer [B] from the viewpoint of ensuring sensitivity and developability as a resist. To 30 parts by mass, preferably 1 to 20 parts by mass. If the total amount used is less than 0.1 parts by mass, the sensitivity and developability tend to be lowered. On the other hand, when it exceeds 20 parts by mass, the transparency to radiation is lowered, and it tends to be difficult to obtain a rectangular resist pattern.

<[A] Synthesis of Acid Generator>
[A] The acid generator can be synthesized by, for example, the following (i) synthesis method, (ii) synthesis method, and the like.

In the above (i) synthesis method, (ii) synthesis method,
(A) X ¹ is a hydrogen atom, a halogen atom or —O—SO ₂ —Q (Q is an alkyl group such as a methyl group, a phenyl group or a toluyl group, or an aryl group), and X ² is (B) X ¹ is a hydroxyl group, and X ² is a hydrogen atom, a halogen atom or —O—SO ₂ —Q (Q is a methyl group, a phenyl group or a toluyl group). is there.
Preferably (a) X ¹ is a hydrogen atom, a halogen atom or —O—SO ₂ —Q (Q is an alkyl group such as a methyl group, a phenyl group or a toluyl group, or an aryl group), and X ² As a case of a hydroxyl group.
X ³ is a hydrogen atom, a halogen atom or —O—SO ₂ —Q (Q is an alkyl group such as a methyl group, a phenyl group or a toluyl group, or an aryl group).

[(I) Synthesis method]
(I) In the synthesis method, compounds (G-1) and (G-2) and a base compound (hereinafter referred to as “(β) base”) are added to a solvent (hereinafter referred to as “(α) solvent”). After the reaction, after the reaction, the [A] acid generator can be obtained after purification by distillation, recrystallization, column chromatography, liquid-liquid washing, solid-liquid washing or the like, if necessary. (Α) Solvent and (β) base may not be used in some cases.

  Examples of the (α) solvent include heptane, hexane, diethyl ether, dichloromethane, chloroform, tetrahydrofuran, ethyl acetate, dimethylformamide, acetonitrile, dimethylacetamide, N-methylpyrrolidone, dioxane, acetone, methyl ethyl ketone, methyl isobutyl ketone, water and the like. Can be mentioned. Two or more of these may be used.

  Examples of the (β) base include trimethylamine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine, diisopropylamine, dicyclohexylamine, 1-methylpiperidine, 1-methylpyrrolidine, quinuclidine, 1,4-diazabicyclo [2.2. 2] Octane, 1,8-diazabicyclo [5.4.0] undec-7-ene, pyridine, 4-dimethylaminopyridine, 4-methylpyridine, 2,6-dimethylpyridine, 2,6-diisopropylpyridine, 2 , 6-di-t-butylpyridine, lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, cesium carbonate, sodium bicarbonate, potassium bicarbonate, lithium, sodium, potassium, lithium hydride, hydrogen Sodium, potassium hydride, calcium hydride, lithium diisopropylamide, n- butyl lithium, s- butyl lithium, t- butyl lithium, sodium -t- butoxide, potassium -t- butoxide. Two or more of these may be used.

Compound (G-1), for example when using bromine in X ^1, it can be synthesized according to the following such schemes. If necessary, acidic compounds such as p-toluenesulfonic acid, camphorsulfonic acid, sulfuric acid, (β) base, and (α) solvent may be used.

Compound (G-2) is, for example, when using a hydroxyl group in X ^2, can be synthesized according to the following such schemes. In other words, X ³ in (G-3) can be synthesized by sulfinating with a sulfinating agent and then oxidizing with an oxidizing agent. Moreover, if Y contains a double bond, (G-2) can also be obtained using, for example, NaHSO ₃ , KHSO ₃ , Na ₂ SO ₃ , K ₂ SO ₃ or the like. If necessary, (β) base and (α) solvent may be used.

  Examples of the sulfinating agent include lithium dithionite, sodium dithionite, potassium dithionite, ammonium dithionite, lithium hydroxymethanesulfinate, sodium hydroxymethanesulfinate, potassium hydroxymethanesulfinate, hydroxy Examples include ammonium methanesulfinate, lithium sulfite, sodium sulfite, potassium sulfite, ammonium sulfite, lithium hydrogen sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, and ammonium hydrogen sulfite. Of these, sodium dithionite and potassium dithionite are preferred, and sodium dithionite is more preferred.

  Oxidizing agents include hydrogen peroxide, metachloroperbenzoic acid, t-butyl hydroperoxide, potassium peroxysulfate, potassium permanganate, sodium perborate, sodium metaiodate, chromic acid, sodium dichromate, halogen, iodo Examples thereof include benzene dichloride, iodobenzene diacetate, osmium oxide (VIII), ruthenium oxide (VIII), sodium hypochlorite, sodium chlorite, oxygen gas, ozone gas and the like. Of these, hydrogen peroxide, metachloroperbenzoic acid, and t-butyl hydroperoxide are preferred. When oxidation is performed, a transition metal catalyst can be used in combination with the oxidizing agent as an additive. Examples of the transition metal catalyst include disodium tungstate, iron (III) chloride, ruthenium (III) chloride, selenium oxide (IV) and the like. Of these, disodium tungstate is preferred.

[(Ii) Synthesis method]
(Ii) In the synthesis method, compound (G-1), (G-3), and (β) base are first added to (α) solvent, and (G-4) can be synthesized by reacting them. (Α) Solvent and (β) base may not be used in some cases. After the reaction, it may be purified by distillation, recrystallization, column chromatography, liquid-liquid washing, solid-liquid washing or the like, if necessary. The obtained (G-4) can be operated in the same manner as in the synthesis method of (G-2) to obtain an [A] acid generator. After the reaction, it may be purified by distillation, recrystallization, column chromatography, liquid-liquid washing, solid-liquid washing or the like, if necessary.

In (i) the synthesis method and (ii) the synthesis method, the structure of R ¹ may be changed to another structure by an esterification reaction or a transesterification reaction in the course of the synthesis, if necessary. If necessary, the structure of A ⁺ may be changed to another structure by a salt exchange reaction during the synthesis.

<[B] polymer>
The [B] polymer contained in the radiation-sensitive resin composition has (b1) a structural unit whose solubility in an alkali developer is increased by the action of an acid. That is, the [B] polymer is an alkali-insoluble or hardly-alkali-soluble resin having an acid-dissociable group, and is a resin that becomes alkali-soluble when the acid-dissociable group is dissociated. In the present invention, “alkaline-insoluble or alkali-insoluble” means that the resist film under the alkali development conditions employed when forming a resist pattern from the resist film formed from the radiation-sensitive resin composition. When a film using only the polymer [B] is developed instead of 50%, it means that 50% or more of the initial film thickness of the film remains after development.

[(B1) structural unit]
(B1) Examples of the structural unit include a structural unit represented by the following formula (3).

（式（３）中、Ｒ^７は水素原子又はメチル基である。Ｒ^８〜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の脂環式炭化水素基である。但し、Ｒ^９とＲ^１０とは互いに結合して、それらが結合している炭素原子と共に、炭素数４〜２０の２価の脂環式炭化水素基を形成していてもよい。）

(In Formula (3), R ⁷ is a hydrogen atom or a methyl group. R ^{8 to} R ¹⁰ are each independently an alkyl group having 1 to 4 carbon atoms or an alicyclic hydrocarbon having 4 to 20 carbon atoms. Provided that R ⁹ and R ¹⁰ may be bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms together with the carbon atom to which they are bonded. .)

  Examples of the alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, and t-butyl group. Is mentioned.

As the alicyclic hydrocarbon group having 4 to 20 carbon atoms, or the alicyclic hydrocarbon group having 4 to 20 carbon atoms formed together with the carbon atom to which R ⁹ and R ¹⁰ are bonded to each other. Includes a polycyclic alicyclic group having a bridged skeleton such as an adamantane skeleton or a norbornane skeleton; and a monocyclic alicyclic group having a cycloalkane skeleton such as cyclopentane or cyclohexane. In addition, these groups may be substituted with one or more linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms, for example.

  (B1) As the structural unit, a structural unit represented by the following formula is preferred.

In the above formula, R ⁷ has the same meaning as the above formula (3). R ¹¹ is an alkyl group having 1 to 4 carbon atoms. m is an integer of 1-6.

  Among these, structural units represented by the following formulas (3-1) to (3-20) are more preferable, and (3-2), (3-3), (3-4), (3-11), (3-12) and (3-13) are particularly preferred.

In the above formula, R ⁷ has the same meaning as the above formula (3).

  [B] In the polymer, the content ratio of (b1) structural units is preferably 5 mol% to 80 mol%, more preferably 10 mol% to 80 mol%, based on all structural units constituting the [B] polymer, 20 mol% to 70 mol% is particularly preferable. When the content ratio of the structural unit (b1) exceeds 80 mol%, the adhesiveness of the resist film is lowered, and there is a risk of pattern collapse or pattern peeling. In addition, the [B] polymer may have (b1) 1 type, or 2 or more types of structural units.

(B1) Examples of monomers that give structural units include (meth) acrylic acid-bicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-bicyclo [2.2.2] octa. 2-yl ester, (meth) acrylic acid-tricyclo [5.2.1.0 ^2,6 ] dec-7-yl ester, (meth) acrylic acid-tricyclo [3.3.1.1 ^3,7 Deca-1-yl ester, (meth) acrylic acid-tricyclo [3.3.1.1 ^3,7 ] dec-2-yl ester, and the like.

[(B2) Structural unit]
[B] The polymer preferably further has (b2) a structural unit having a lactone skeleton or a cyclic carbonate skeleton. (B2) By having the structural unit, the adhesion of the resist film to the substrate can be improved.

  (B2) As a structural unit, the structural unit shown, for example by a following formula is mentioned.

In the above formula, R ¹² is a hydrogen atom or a methyl group. R ¹³ is a hydrogen atom or a methyl group. R ¹⁴ is a hydrogen atom or a methoxy group. Z is a single bond or a methylene group. B is a methylene group or an oxygen atom. a and b are 0 or 1;

  (B2) As the structural unit, a structural unit represented by the following formula is preferred.

In the above formula, R ¹² is a hydrogen atom or a methyl group.

  In the [B] polymer, the content ratio of the (b2) structural unit is preferably 0 mol% to 70 mol%, more preferably 10 mol% to 60 mol%, based on all structural units constituting the [B] polymer. By setting it as such a content rate, the developability and LWR as a resist can be improved, and a defect property and low PEB temperature dependence can be improved. On the other hand, if it exceeds 70 mol%, the resolution and LWR as a resist may be reduced.

  (B2) As a preferable monomer which gives a structural unit, the monomer as described in an international publication 2007/116664 pamphlet is mentioned, for example.

[(B3) structural unit]
[B] The polymer preferably further has a structural unit (b3) containing a polar group represented by the following formula. Examples of the “polar group” herein include a hydroxyl group, a carboxyl group, a keto group, a sulfonamide group, an amino group, an amide group, and a cyano group.

  (B3) As a structural unit, the structural unit shown, for example by a following formula is mentioned.

In the above formula, R ¹⁵ is a hydrogen atom or a methyl group.

(B3) As the structural unit, a structural unit represented by the following formula is preferred.

In the above formula, R ¹⁵ is a hydrogen atom or a methyl group.

  In the [B] polymer, the content ratio of the (b3) structural unit is preferably 0 mol% to 30 mol%, more preferably 5 mol% to 20 mol%, based on all structural units constituting the [B] polymer.

<[B] Polymer Synthesis Method>
[B] The polymer can be synthesized according to a conventional method such as radical polymerization. For example,
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;
A method in which a solution containing a monomer and a solution containing a radical initiator are separately dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction;
A plurality of types of solutions containing each monomer and a solution containing a radical initiator are separately added to a reaction solvent or a solution containing a monomer and synthesized by a method such as a polymerization reaction. It is preferable. In addition, when the monomer solution is dropped and reacted with respect to the monomer solution, the amount of the monomer in the dropped monomer solution is 30 mol% with respect to the total amount of monomers used for polymerization. The above is preferable, 50 mol% or more is more preferable, and 70 mol% or more is particularly preferable.

  What is necessary is just to determine the reaction temperature in these methods suitably with initiator seed | species. Usually, it is 30 to 180 ° C, preferably 40 to 160 ° C, and more preferably 50 to 140 ° C. The dropping time varies depending on the reaction temperature, the type of initiator, the monomer to be reacted, etc., but is usually 30 minutes to 8 hours, preferably 45 minutes to 6 hours, and more preferably 1 hour to 5 hours. . Further, the total reaction time including the dropping time varies depending on the conditions similarly to the dropping time, but is usually 30 minutes to 8 hours, preferably 45 minutes to 7 hours, and more preferably 1 hour to 6 hours.

  Examples of the radical initiator used in the polymerization include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2 -Cyclopropylpropionitrile), 2,2'-azobis (2,4-dimethylvaleronitrile) and the like. These initiators can be used alone or in admixture of two or more.

  The polymerization solvent is not limited as long as it is a solvent other than a solvent that inhibits polymerization (nitrobenzene having a polymerization inhibiting effect, mercapto compound having a chain transfer effect, etc.) and can dissolve the monomer. Examples of the polymerization solvent include alcohol solvents, ketone solvents, amide solvents, ester / lactone solvents, nitrile solvents, and mixed solvents thereof. These solvents can be used alone or in combination of two or more.

  The resin obtained by the polymerization reaction is preferably recovered by a reprecipitation method. That is, after completion of the polymerization reaction, the target resin is recovered as a powder by introducing the polymerization solution into a reprecipitation solvent. As the reprecipitation solvent, alcohols or alkanes can be used alone or in admixture of two or more. In addition to the reprecipitation method, the resin 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.

  [B] The weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is not particularly limited, but is preferably 1,000 or more and 500,000 or less, more preferably 2,000 or more and 400,000 or less. Preferably, it is 3,000 or more and 300,000 or less. In addition, when the Mw of the [B] polymer is less than 1,000, the heat resistance when used as a resist tends to decrease. On the other hand, when the Mw of the [B] polymer exceeds 500,000, the developability when used as a resist tends to be lowered.

  [B] The ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer is usually from 1 to 5, preferably from 1 to 3, preferably from 1 to 2. More preferred. By setting Mw / Mn in such a range, the photoresist film has excellent resolution performance.

  Mw and Mn in this specification are GPC columns (Tosoh Corp., 2 G2000HXL, 1 G3000HXL, 1 G4000HXL) under the analysis conditions of a flow rate of 1.0 ml / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C. The value measured by GPC using monodisperse polystyrene as a standard.

<[C] polymer>
The said radiation sensitive resin composition can further contain the polymer which has a [C] fluorine atom as a suitable component. When the radiation-sensitive composition contains a [C] polymer, the hydrophobicity of the resist film is improved, and even when immersion exposure is performed, it is excellent in suppression of substance elution, and the resist film and the immersion liquid The receding contact angle can be made sufficiently high, and when the scan exposure is performed at a high speed, there are effects such as no water droplets remaining, so that the usefulness of the radiation sensitive composition for immersion exposure is enhanced.

[C] Examples of the polymer having a fluorine atom include 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.

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

  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 side Examples thereof include ester compounds in which the 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.

  Examples of the monomer that gives a structure in which a fluorinated alkyl group is bonded to the main chain and the side chain include α-trifluoromethylacrylic acid, β-trifluoromethylacrylic acid, α, β-trifluoromethylacrylic acid, and the like. Is a fluorinated alkyl group or its derivative ester compound. One or more vinyl moiety hydrogens are substituted with a fluorinated alkyl group such as a trifluoromethyl group. The hydrogen bonded to the double bond of one or more alicyclic olefin compounds is replaced with a fluorinated alkyl group such as a trifluoromethyl group, and the side chain is a fluorinated alkyl group or a derivative thereof. And the like. In addition, an alicyclic olefin compound shows the compound in which a part of ring is a double bond.

  [C] The polymer preferably has (c1) structural unit represented by the following formula (4) and / or (c2) structural unit represented by formula (5), and (c1) structural unit and (c2 ) You may have "other structural units" other than a structural unit. Hereinafter, each structural unit will be described in detail.

[(C1) Structural unit]
(C1) The structural unit is a structural unit represented by the following formula (4).

（式（４）中、Ｒ^１６は水素原子、フッ素原子、メチル基又はトリフルオロメチル基である。Ｒ^１７はフッ素原子を有する炭素数１〜６の直鎖状若しくは分岐状のアルキル基、又はフッ素原子を有する炭素数４〜２０の１価の脂環式炭化水素基である。但し、上記アルキル基及び脂環式炭化水素基は、水素原子の一部又は全部が置換されていてもよい。）

(In the formula (4), R ¹⁶ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ¹⁷ is a linear or branched alkyl group having 1 to 6 carbon atoms having a fluorine atom, or It is a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms and having a fluorine atom, provided that the alkyl group and the alicyclic hydrocarbon group may have part or all of the hydrogen atoms substituted. .)

  As said C1-C6 linear or branched alkyl group, a methyl group, an ethyl group, a propyl group, a butyl group etc. are mentioned, for example.

  Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms include a cyclopentyl group, a cyclopentylpropyl group, a cyclohexyl group, a cyclohexylmethyl group, a cycloheptyl group, a cyclooctyl group, and a cyclooctylmethyl group.

  (C1) Monomers that give structural units include, for example, trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, 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 (meth) 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) hex (Meth) acrylate, perfluorocyclohexylmethyl (meth) acrylate, 1- (2,2,3,3,3-pentafluoro) propyl (meth) acrylate, 1- (2,2,3,3,4, 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 (c1) include structural units represented by the following formulas (4-1) and (4-2).

（式（４−１）及び（４−２）中、Ｒ^１６は上記式（４）と同義である。）

(In the formulas (4-1) and (4-2), R ¹⁶ has the same meaning as the above formula (4).)

  In the [C] polymer, the content of the (c1) structural unit is preferably 10 mol% to 70 mol%, more preferably 20 mol% to 60 mol%, based on all the structural units constituting the [C] polymer. In addition, the [C] polymer may have 1 type (s) or 2 or more types of (c1) structural units.

[(C2) Structural unit]
(C2) The structural unit is a structural unit represented by the following formula (5).

（式（５）中、Ｒ^１８は水素原子、メチル基又はトリフルオロメチル基である。Ｒ^１９は（ｋ＋１）価の連結基である。Ｘはフッ素原子を有する２価の連結基である。Ｒ^２０は水素原子又は１価の有機基である。ｋは１〜３の整数である。但し、ｋが２又は３の場合、複数のＸ及びＲ^２０はそれぞれ同一であっても異なっていてもよい。）

(In Formula (5), R ¹⁸ is a hydrogen atom, a methyl group or a trifluoromethyl group. R ¹⁹ is a (k + 1) -valent linking group. X is a divalent linking group having a fluorine atom. R ²⁰ is a hydrogen atom or a monovalent organic group, k is an integer of 1 to 3. However, when k is 2 or 3, a plurality of X and R ²⁰ may be the same or different. May be.)

In the above formula (5), the (k + 1) -valent linking group represented by R ¹⁹ is, for example, a linear or branched hydrocarbon group having 1 to 30 carbon atoms or an alicyclic hydrocarbon having 3 to 30 carbon atoms. A group, an aromatic hydrocarbon group having 6 to 30 carbon atoms, or one or more groups selected from the group consisting of these groups and an oxygen atom, a sulfur atom, an ether group, an ester group, a carbonyl group, an imino group, and an amide group And a combination of these. The (k + 1) -valent linking group may have a substituent.

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

Examples of the alicyclic hydrocarbon group having 3 to 30 carbon atoms include monocyclic saturated hydrocarbons such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, methylcyclohexane, and ethylcyclohexane;
Monocyclic unsaturated hydrocarbons such as cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclodecene, cyclopentadiene, cyclohexadiene, cyclooctadiene, cyclodecadiene;
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 ] polycyclic saturated hydrocarbons such as dodecane and adamantane;
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 . And a group obtained by removing (m + 1) hydrogen atoms from a polycyclic hydrocarbon group such as 0 ^2,7 ] dodecene.

  Examples of the aromatic hydrocarbon group having 6 to 30 carbon atoms include an aromatic hydrocarbon group such as benzene, naphthalene, phenanthrene, anthracene, tetracene, pentacene, pyrene, picene, toluene, xylene, ethylbenzene, mesitylene, cumene and the like (m + 1). ) Groups from which a single hydrogen atom has been removed.

  In the formula (5), examples of the divalent linking group having a fluorine atom represented by X include a C 1-20 divalent linear hydrocarbon group having a fluorine atom. Examples of X include structures represented by the following formulas (X-1) to (X-6).

  X is preferably a structure represented by the above formulas (X-1) and (X-2).

In the above formula (5), examples of the organic group represented by R ²⁰ 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 Is mentioned.

  Examples of the structural unit (c2) include structural units represented by the following formulas (5-1) and (5-2).

（式（５−１）中、Ｒ^１９は炭素数１〜２０の２価の直鎖状、分岐状又は環状の飽和若しくは不飽和の炭化水素基である。Ｒ^１８、Ｘ及びＲ^２０は上記式（５）と同義である。
式（５−２）中、Ｒ^１８、Ｘ、Ｒ^２０及びｋは上記式（５）と同義である。但し、ｋが２又は３の場合、複数のＸ及びＲ^２０はそれぞれ同一であっても異なっていてもよい。）

(In the formula (5-1), R ¹⁹ is a divalent linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. R ¹⁸ , X and R ²⁰ are the above. It is synonymous with Formula (5).
In the formula (5-2), R ¹⁸ , X, R ²⁰ and k have the same meanings as in the above formula (5). However, when k is 2 or 3, the plurality of X and R ²⁰ may be the same or different. )

  Examples of the structural unit represented by the above formula (5-1) and formula (5-2) include the following formula (5-1-1), formula (5-1-2) and formula (5-2-1). The structural unit shown by these is mentioned.

（式（５−１−１）、（５−１−２）及び（５−２−１）中、Ｒ^１８は上記式（５）と同義である。）

(In the formulas (5-1-1), (5-1-2) and (5-2-1), R ¹⁸ has the same meaning as the above formula (5).)

  (C2) Monomers that give structural units include, for example, (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 (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-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.

  In the [C] polymer, the content of the (c2) structural unit is preferably 20 mol% to 80 mol%, more preferably 30 mol% to 70 mol%, based on all the structural units constituting the [C] polymer. In addition, a [C] polymer may have 1 type, or 2 or more types of (c2) structural units.

[Other structural units]
[C] The polymer further includes, as “other structural units”, a structural unit containing a lactone structure for enhancing solubility in a developer, a structural unit containing an alicyclic structure for enhancing etching resistance, and the like. You may have more. Examples of the structural unit containing the lactone structure and the structural unit containing the alicyclic structure include structural units similar to the structural unit having the lactone structure of the [B] polymer.

  In the [C] polymer, the content of other structural units is usually 90 mol% or less, preferably 10 mol% to 80 mol%, preferably 20 mol% to 70 mol, based on all structural units constituting the [C] polymer. % Is more preferable. In addition, the [C] polymer may have 1 type, or 2 or more types of other structural units.

  [C] As a compounding quantity of a polymer, 0.1 mass part-20 mass parts are preferable with respect to 100 mass parts of [B] polymers, 1 mass part-10 mass parts are more preferable, and 1 mass part- 7.5 parts by mass is particularly preferable. If it is less than 0.1 part by mass, the effect of containing the [C] polymer may not be sufficient. On the other hand, when the amount exceeds 20 parts by mass, the water repellency of the resist surface becomes too high and development failure may occur.

[C] The fluorine atom content in the polymer is preferably larger than that in the [B] polymer. The content ratio of fluorine atoms in the [C] polymer is usually 5% by mass or more, preferably 5% by mass to 50% by mass, more preferably 5%, based on 100% by mass of the total amount of the [C] polymer. It is mass%-45 mass%. In addition, this fluorine atom content rate can be measured by ¹³ C-NMR. The photoresist formed by the radiation sensitive resin composition containing the [C] polymer and the [B] polymer as the fluorine atom content ratio in the [C] polymer is larger than that of the [B] polymer. The water repellency of the film surface can be increased, and there is no need to separately form an upper layer film during immersion exposure. In order to sufficiently exhibit the above effect, the difference between the fluorine atom content in the [B] polymer and the fluorine atom content in the [C] polymer is 1% by mass or more. Preferably, it is 3 mass% or more.

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

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

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

  [C] The Mw of the polymer is preferably 1,000 to 50,000, more preferably 1,000 to 40,000, and particularly preferably 1,000 to 30,000. [C] When the Mw of the polymer is less than 1,000, a sufficient receding contact angle cannot be obtained. On the other hand, when Mw exceeds 50,000, the developability of the resist tends to decrease.

  [C] The ratio (Mw / Mn) between the polymer Mw and the polystyrene-equivalent number average molecular weight (Mn) by the GPC method is preferably 1 to 5, and more preferably 1 to 4.

<[D] Nitrogen-containing compound>
[D] The nitrogen-containing compound controls the diffusion phenomenon in the resist film of the acid generated from the [A] acid generator upon exposure, and has the effect of suppressing undesirable chemical reactions in the non-exposed areas. While improving further, the storage stability of the obtained radiation sensitive resin composition improves. [D] The inclusion form of the nitrogen-containing compound in the radiation-sensitive resin composition may be a free compound form, a form incorporated as part of a polymer, or both forms.

  [D] The nitrogen-containing compound is represented by the following formula, for example.

In the above formula, R ^{21 to} R ²⁵ are each independently a hydrogen atom, or a linear, branched, or cyclic C 1-20 alkyl group, aryl group, or aralkyl group. However, these groups may have a substituent. Further, R ²¹ and R ²² are bonded to each other with a nitrogen atom to which each is bonded and / or R ²³ and R ²⁴ are bonded to each other with a carbon atom to which each is bonded to form a divalent saturation having 4 to 20 carbon atoms. Alternatively, an unsaturated hydrocarbon group or a derivative thereof may be formed.

  Examples of the [D] nitrogen-containing compound represented by the above formula include Nt-butoxycarbonyldi-n-octylamine, Nt-amyloxycarbonyldi-n-octylamine, and Nt-butoxycarbonyldi- -N-nonylamine, Nt-amyloxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt-amyloxycarbonyldi-n-decylamine, Nt-butoxycarbonyldicyclohexyl Amine, Nt-amyloxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-amyloxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, N -T-amyloxycarbonyl-2-adamantylamine, N- -Butoxycarbonyl-N-methyl-1-adamantylamine, Nt-amyloxycarbonyl-N-methyl-1-adamantylamine, (S)-(-)-1- (t-butoxycarbonyl) -2-pyrrolidine Methanol, (S)-(−)-1- (t-amyloxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (R) -(+)-1- (t-amyloxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl-4-hydroxypiperidine, Nt-butoxy Carbonylpyrrolidine, Nt-amyloxycarbonylpyrrolidine, N, N′-di-t-butoxycarbonylpiperazine, N, '-Di-t-amyloxycarbonylpiperazine, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-amyloxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl -4,4'-diaminodiphenylmethane, Nt-amyloxycarbonyl-4,4'-diaminodiphenylmethane, N, N'-di-t-butoxycarbonylhexamethylenediamine, N, N'-di-t-ami Roxycarbonylhexamethylenediamine, N, N, N ′, N′-tetra-t-butoxycarbonylhexamethylenediamine, N, N, N ′, N′-tetra-t-amyloxycarbonylhexamethylenediamine, N, N '-Di-t-butoxycarbonyl-1,7-diaminoheptane, N, N'-di-t-amyloxycarbo Nyl-1,7-diaminoheptane, N, N′-di-t-butoxycarbonyl-1,8-diaminooctane, N, N′-di-t-amyloxycarbonyl-1,8-diaminooctane, N, N′-di-t-butoxycarbonyl-1,9-diaminononane, N, N′-di-t-amyloxycarbonyl-1,9-diaminononane, N, N′-di-t-butoxycarbonyl-1,10 -Diaminodecane, N, N'-di-t-amyloxycarbonyl-1,10-diaminodecane, N, N'-di-t-butoxycarbonyl-1,12-diaminododecane, N, N'-di- t-amyloxycarbonyl-1,12-diaminododecane, N, N′-di-t-butoxycarbonyl-4,4′-diaminodiphenylmethane, N, N′-di-t-amyloxycarbonyl- , 4′-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonylbenzimidazole, Nt-amyloxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenz Examples thereof include Nt-alkylalkoxycarbonyl group-containing amino compounds such as imidazole and Nt-amyloxycarbonyl-2-phenylbenzimidazole.

  In addition to the nitrogen-containing compound represented by the above formula, examples of the nitrogen-containing compound include a tertiary amine compound, a quaternary ammonium hydroxide compound, a photodegradable base compound, and other nitrogen-containing heterocyclic compounds. It is done.

Examples of tertiary amine compounds include triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine. , Tri (cyclo) alkylamines such as cyclohexyldimethylamine, dicyclohexylmethylamine, and tricyclohexylamine;
Fragrances such as aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, 2,6-dimethylaniline, 2,6-diisopropylaniline Group amines;
Alkanolamines such as triethanolamine and N, N-di (hydroxyethyl) aniline;
N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, 1,3-bis [1- (4-aminophenyl) -1- Methylethyl] benzenetetramethylenediamine, bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) ether and the like.

  Examples of the quaternary ammonium hydroxide compound include tetra-n-propylammonium hydroxide and tetra-n-butylammonium hydroxide.

  [D] As a content rate of a nitrogen-containing compound, 10 mass parts or less are preferable with respect to 100 mass parts of [B] polymers, and 8 mass parts or less are more preferable. When the amount used exceeds 10 parts by mass, the sensitivity as a resist tends to decrease.

[[E] solvent]
The radiation-sensitive resin composition usually contains an [E] solvent. [E] Examples of the solvent include alcohol solvents, ketone solvents, amide solvents, ether solvents, ester solvents, and mixed solvents thereof.

Examples of alcohol solvents include 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 -Monoalcohol solvents such as heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, 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- Ketones such as hexyl ketone, di-iso-butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, diacetone alcohol, acetophenone A solvent is mentioned.

  Examples of the amide solvents include N, N′-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone and the like can be mentioned.

  Examples of the ester solvents include diethyl carbonate, propylene carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, γ-valerolactone, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec sec -Butyl, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, acetoacetic acid Methyl, ethyl acetoacetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol acetate Cole mono-n-butyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, diacetic acid Glycol, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate , Diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

Examples of other solvents include n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, cyclohexane, Aliphatic hydrocarbon solvents such as methylcyclohexane;
Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propylbenzene and n-amylnaphthalene Group hydrocarbon solvents;
And halogen-containing solvents such as dichloromethane, chloroform, chlorofluorocarbon, chlorobenzene, and dichlorobenzene.

  Of these solvents, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, γ-butyrolactone, and cyclohexanone are preferable.

<Other optional components>
The said radiation sensitive resin composition can contain a [F] uneven distribution promoter, an alicyclic skeleton compound, surfactant, a sensitizer, etc. in the range which does not impair the effect of this invention. Hereinafter, these other optional components will be described in detail. These other optional components can be used alone or in admixture of two or more. Moreover, the compounding quantity of another arbitrary component can be suitably determined according to the objective.

[[F] uneven distribution promoter]
The radiation-sensitive resin composition can be blended with an [F] uneven distribution accelerator when a resist pattern is formed using an immersion exposure method. By blending [F] an uneven distribution promoter, the [C] polymer can be further unevenly distributed in the vicinity of the surface layer. [F] Examples of the uneven distribution promoter include γ-butyrolactone and propylene carbonate.

[Alicyclic skeleton compound]
An alicyclic skeleton compound is a component that exhibits an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like. Examples of the alicyclic skeleton compound include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylic acid t-butyl; deoxycholic acid t-butyl, deoxycholic acid t-butoxycarbonylmethyl, Deoxycholic acid esters such as 2-ethoxyethyl deoxycholic acid; Lithocholic acid esters such as tert-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid; 3- [2-hydroxy-2 , 2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] nonane, and the like.

[Surfactant]
Surfactants are components that have the effect of improving coatability, striation, developability, and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol diacrylate. In addition to nonionic surfactants such as stearate, the following trade names are KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, Kyoeisha Chemical Co., Ltd.), Ftop EF301, EF303, EF352 (above, Tochem Products), MegaFuck F171, F173 (above, 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 (above, Asahi Glass Co., Ltd.) ) And the like.

[Sensitizer]
The sensitizer absorbs radiation energy and transmits the energy to the [A] acid generator, thereby increasing the amount of acid produced. It has the effect of improving the “apparent sensitivity”. Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like.

<Preparation of radiation-sensitive composition>
The said radiation sensitive resin composition mixes the said [A] acid generator, a [B] polymer, a [C] polymer, and another arbitrary component in a predetermined ratio, for example in the said [E] solvent. Can be prepared. The organic solvent is exemplified as the above [E] solvent, and can dissolve or disperse the [A] acid generator, the [B] polymer, the [C] polymer, and other optional components. If it does not specifically limit. The radiation-sensitive resin composition is usually dissolved in an [E] solvent so that the total solid content concentration is 1% by mass to 50% by mass, preferably 2% by mass to 25% by mass, in use. For example, it is prepared by filtering with a filter having a pore size of about 0.2 μm.

<Pattern formation method>
The pattern forming method of the present invention comprises:
A step of applying the radiation-sensitive resin composition to a substrate and forming a resist film (hereinafter sometimes referred to as “(i) step”);
A step of exposing the resist film (hereinafter sometimes referred to as “(ii) step”), and a step of alkali developing the exposed resist film (hereinafter also referred to as “(iii) step”).
including. Hereinafter, each process is explained in full detail.

[(I) Step]
In this step, a radiation sensitive resin composition or a composition solution obtained by dissolving this in a solvent is applied to a silicon wafer, silicon dioxide, antireflection film by coating means such as spin coating, cast coating, roll coating, etc. The resist film is formed by applying a predetermined film thickness on a substrate such as a wafer coated with, and then pre-baking to volatilize the solvent in the coating film.

[Step (ii)]
In this step, the resist film formed in the step (i) is exposed by irradiation with radiation (in some cases, through an immersion medium such as water). At this time, radiation is irradiated through a mask having a predetermined pattern. As the radiation, irradiation is performed by appropriately selecting from visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams and the like according to the line width of the target pattern. Far ultraviolet rays represented by ArF excimer laser (wavelength 193 nm) and KrF excimer laser (wavelength 248 nm) are preferable, and ArF excimer laser is more preferable. Next, the exposed photoresist film is subjected to post-exposure baking (PEB), whereby the polymer generated from the acid generated from the [A] acid generator is deprotected in the exposed portion of the resist film. PEB is normally selected and carried out in the range of 50 ° C to 180 ° C.

[(Iii) Step]
In this step, a predetermined photoresist pattern is formed by developing the exposed resist film with a developer. After development, it is common to wash with water and dry. As the developer, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyl Dimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4.3.0] An aqueous alkaline solution in which at least one alkaline compound such as -5-nonene is dissolved is preferable.

  When performing immersion exposure, before the step (ii), in order to protect the direct contact between the immersion liquid and the resist film, an immersion liquid insoluble immersion protective film is formed on the resist film. It may be provided. Examples of the immersion protective film include a solvent peeling type protective film that is peeled off by a solvent before the step (iii) (see, for example, JP-A-2006-227632), and (ii) a developer peeling that peels off simultaneously with the development in the step. Any of the mold protective films (for example, refer to WO2005-069096 and WO2006-035790) may be used. However, from the viewpoint of throughput, it is preferable to use a developer peeling type immersion protective film.

  The resist pattern obtained in this way has a good rectangularity with a top loss prevented, and is suitable for fine processing using a lithography technique.

<Compound>
The compound of the present invention is represented by the above formula (1) or formula (2). The compound can be suitably used as an acid generator contained in a resist composition or the like. Detailed description of the compound is omitted in the description of [A] acid generator contained in the radiation-sensitive resin composition, and is therefore omitted here.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

<[A] Synthesis of Acid Generator>
[Example 1]
(Precursor synthesis)
In a glass flask equipped with a thermometer and a condenser, 10 g (44.4 mmol) of 1-bromo-1,1,2,2-tetrafluorobutanol, 6.34 g (75.5 mmol) of sodium hydrogen carbonate, sodium dithionite 12.4 g (72.2 mmol), 20 mL of acetonitrile and 15 mL of water were added and reacted at 60 ° C. for 10 hours. After confirming the completion of the reaction by ¹⁹ F-NMR, the reaction solution was cooled to room temperature, 20 mL of water was added to the reaction solution, and then extracted 10 times with 30 mL of acetonitrile. The obtained acetonitrile solution was concentrated and dried to obtain a crude product of sodium 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfinate shown below (11.3 g).

In a glass flask equipped with a thermometer and a condenser, 11.3 g of a crude product of sodium 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfinate, tungstic acid (IV) sodium dihydrate The catalyst was charged with a catalyst amount and 25 mL of water and stirred. Thereafter, 5.4 g of 35% hydrogen peroxide water was added dropwise in an ice bath. After completion of the dropwise addition, the mixture was stirred at room temperature for 3 hours, and the completion of the reaction was confirmed by ¹⁹ F-NMR. After 50 mL of water was added to the aqueous solution after the reaction, the drunk solution was washed with 25 ml of dichloromethane to obtain an aqueous solution of sodium 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonate shown below.

  After delivering 75 mL of the aqueous solution of sodium 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonate obtained above to a glass flask equipped with a thermometer and a condenser, triphenylsulfonium bromide 9 After adding 9 g, the mixture was stirred at room temperature for 3 hours. After completion of the reaction, the resulting aqueous solution was extracted four times with 50 mL of dichloromethane, and the organic phase was washed twice with 50 ml of water. After recovering the organic phase, it was concentrated and dried to obtain 10.9 g of triphenylsulfonium 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonate shown below.

¹ H-NMR (CDCl ₃ ) δ (ppm): 7.74 (15H), 3.88 (2H), 2.60 (2H)
¹⁹ F-NMR (CDCl ₃ ) δ (ppm): −110.7 (2F), −117.7 (2F)

(Synthesis of A-1)
In a glass flask equipped with a thermometer and a condenser, 3 g (6.15 mmol) of triphenylsulfonium 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonate, 1.70 g (12.30 mmol) of potassium carbonate. ), 10 mL of acetone was added, and the mixture was stirred at 50 ° C. for 30 minutes. Thereafter, 1.60 g (5.54 mmol) of 1-methyladamantyl 2-bromoacetate was added, and the mixture was further stirred for 10 hours. After completion of the reaction, the organic phase was separated, 50 mL of dichloromethane was added, and this solution was washed 5 times with 50 mL of water. The obtained organic phase was concentrated and decompressed to obtain a white solid acid generator (A-1) shown below (3.46 g, yield 81%).

¹ H-NMR (CDCl ₃ ) δ (ppm): 7.74 (15H), 4.01 (2H), 3.89 (2H), 2.64 (2H), 2.33 (2H), 2. 05-1.54 (15H)
¹⁹ F-NMR (CDCl ₃ ) δ (ppm): −111.6 (2F), −117.8 (2F)

[Example 2]
(Synthesis of A-2)
In a glass flask equipped with a thermometer and a condenser, 3 g (6.15 mmol) of triphenylsulfonium 1,1,2,2-tetrafluoro-4-hydroxybutane-1-sulfonate, 1.70 g (12.30 mmol) of potassium carbonate. ), 10 mL of acetone was added, and the mixture was stirred at 50 ° C. for 30 minutes. Thereafter, 1.52 g (5.54 mmol) of 4-oxa-5oxotricyclo [4.2.1.0 ^3,7 ] nonan-2-yl 2-bromoacetate was added, and the mixture was further stirred for 10 hours. After completion of the reaction, the organic phase was separated, 50 ml of dichloromethane was added, and this solution was washed 5 times with 50 mL of water. The obtained organic phase was concentrated and reduced in pressure to obtain a white solid acid generator (A-2) (3.48 g, yield 83%).

¹ H-NMR (CDCl ₃ ) δ (ppm): 7.74 (15H), 4.51 (1H), 4.33 (1H), 4.02 (2H), 3.90 (2H), 3. 21 (1H), 2.73-2.42 (4H), 2.23-1.95 (2H), 1.63 (2H)
¹⁹ F-NMR (CDCl ₃ ) δ (ppm): −111.8 (2F), −117.8 (2F)

  A-3 to A-6 as other acid generators used in Examples and Comparative Examples have the following structures.

<[B] Synthesis of polymer>

  The monomers used for the synthesis of [B] polymer, [C] polymer and [G] polymer for upper layer film described below are shown below.

[Synthesis Example 1]
21.54 g (50 mol%) of the compound (M-1) and 28.46 g (50 mol%) of the compound (M-9) were dissolved in 100 g of 2-butanone, and 2.13 g of azobisisobutyronitrile was further added. A monomer solution was prepared. A 500 mL three-necked flask charged with 50 g of 2-butanone was purged with nitrogen for 30 minutes, and then the reactor was heated to 80 ° C. with stirring, and the monomer solution prepared as described above was added to the flask using a dropping funnel. It was added dropwise over time. 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, and poured into 1,000 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was dispersed in 200 g of methanol, washed in the form of a slurry, and then filtered off twice. The white powder copolymer (B-1) was obtained by drying at 50 ° C. for 17 hours (yield 31 g, yield 62%). This copolymer had Mw of 6,100, Mw / Mn of 1.4, and a fluorine atom content of 0.0%.
As a result of ¹³ C-NMR analysis, the content ratios of (M-1) and (M-9) were 48 mol% and 52 mol%, respectively.

[Synthesis Example 2]
14.20 g (35 mol%) of the compound (M-1) and 26.81 g (50 mol%) of the compound (M-9) were dissolved in 100 g of 2-butanone, and further 1.98 g of azobisisobutyronitrile was added. A monomer solution was prepared. A 500 mL three-necked flask charged with 50 g of 2-butanone and 8.9 g (15 mol%) of compound (M-5) was purged with nitrogen for 30 minutes, and then the reactor was heated to 80 ° C. with stirring, as described above. The prepared monomer solution was dropped over 3 hours using a dropping funnel. 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, and poured into 1,000 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was dispersed in 200 g of methanol, washed in the form of a slurry, and then filtered off twice. The white powder copolymer (B-2) was obtained by drying at 50 ° C. for 17 hours (yield 35 g, yield 70%). This copolymer had Mw of 6,300, Mw / Mn of 1.4, and a fluorine atom content of 0.0%.
As a result of ¹³ C-NMR analysis, the content ratios of (M-1), (M-5) and (M-9) were 34 mol%, 14 mol% and 52 mol%, respectively.

[Synthesis Example 3]
19.18 g (40 mol%) of compound (M-3), 3.18 g (10 mol%) of compound (M-8) and 24.43 g (45 mol%) of compound (M-9) were dissolved in 100 g of 2-butanone. Furthermore, a monomer solution charged with 2.00 g of azobisisobutyronitrile was prepared. A 500 mL three-necked flask charged with 50 g of 2-butanone and 3.21 g (5 mol%) of compound (M-6) was purged with nitrogen for 30 minutes, and then the reactor was heated to 80 ° C. with stirring, as described above. The prepared monomer solution was dropped over 3 hours using a dropping funnel. 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, and poured into 1,000 g of methanol, and the precipitated white powder was filtered off. The filtered white powder was dispersed in 200 g of methanol, washed in the form of a slurry, and then filtered off twice. The white powder copolymer (B-3) was obtained by drying at 50 ° C. for 17 hours (yield 37 g, yield 74%). This copolymer had Mw of 6,100, Mw / Mn of 1.3, and a fluorine atom content of 0.0%.
As a result of ¹³ C-NMR analysis, the contents of (M-3), (M-6), (M-8) and (M-9) were 39 mol%, 5 mol%, 10 mol% and 46 mol%, respectively. .

<Synthesis of [C] polymer>
[Synthesis Example 4]
21.50 g (70 mol%) of the compound (M-2) and 8.50 g (30 mol%) of the compound (M-13) were dissolved in 60 g of 2-butanone, and 1.38 g of azobisisobutyronitrile was further added. A monomer solution was prepared. A 300 mL three-necked flask charged with 30 g of 2-butanone was purged with nitrogen for 30 minutes, and then the reactor was heated to 80 ° C. with stirring, and the monomer solution prepared as described above was added to the flask using a dropping funnel. It was added dropwise over time. 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 less, and poured into a solution of 600 g of methanol: water = 8: 2 to precipitate the resin. After removing the supernatant solution, 120 g of methanol was added to the precipitated resin to wash the resin. After removing the supernatant, it was dried at 50 ° C. for 17 hours to obtain a copolymer (C-1) of the above compounds (M-2) and (M-13) (yield 18 g, yield 60). %). This copolymer had Mw of 5,800, Mw / Mn of 1.4, and fluorine atom content of 9.6% by mass.

[Synthesis Example 5]
Compound (M-7) 11.22 g (40 mol%) and compound (M-11) 18.78 g (60 mol%) were dissolved in 2-butanone 60 g, and 1.03 g of azobisisobutyronitrile was added. A monomer solution was prepared. A 300 mL three-necked flask charged with 30 g of 2-butanone was purged with nitrogen for 30 minutes, and then the reactor was heated to 80 ° C. with stirring, and the monomer solution prepared as described above was added to the flask using a dropping funnel. It was added dropwise over time. 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 less, and poured into a solution of 600 g of methanol: water = 8: 2 to precipitate the resin. After removing the supernatant solution, 120 g of methanol was added to the precipitated resin to wash the resin. After removing the supernatant, it was dried at 50 ° C. for 17 hours to obtain a copolymer (C-2) of the above compounds (M-7) and (M-11) (yield 19 g, yield 62). %). This copolymer had Mw of 5,700, Mw / Mn of 1.4, and fluorine atom content of 9.5% by mass.

[Synthesis Example 6]
12.24 g (40 mol%) of the compound (M-4) and 17.76 g (60 mol%) of the compound (M-12) were dissolved in 60 g of 2-butanone, and 1.03 g of azobisisobutyronitrile was further added. A monomer solution was prepared. A 300 mL three-necked flask charged with 30 g of 2-butanone was purged with nitrogen for 30 minutes, and then the reactor was heated to 80 ° C. with stirring, and the monomer solution prepared as described above was added to the flask using a dropping funnel. It was added dropwise over time. 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 less, and poured into a solution of 600 g of methanol: water = 8: 2 to precipitate the resin. After removing the supernatant solution, 120 g of methanol was added to the precipitated resin to wash the resin. After removing the supernatant, it was dried at 50 ° C. for 17 hours to obtain a copolymer (C-3) of the above compounds (M-4) and (M-12) (yield 20 g, yield 67). %). This copolymer had Mw of 5,900, Mw / Mn of 1.4, and fluorine atom content of 9.5% by mass.

<[G] Synthesis of polymer for upper layer film>
[Synthesis Example 7]
Monomer solution (i) in which 22.26 g of compound (M-10) and 4.64 g of 2,2-azobis (methyl 2-methylisopropionate) were dissolved in 25 g of methyl ethyl ketone, and compound (M-14) A monomer solution (ii) in which 27.74 g was previously dissolved in 25 g of methyl ethyl ketone was prepared. On the other hand, 100 g of methyl ethyl ketone was put into a 500 mL three-necked flask equipped with a thermometer and a dropping funnel and purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the flask was heated to 80 ° C. while stirring with a magnetic stirrer.
Using a dropping funnel, the monomer solution (i) prepared in advance was added dropwise over 20 minutes and aged for 20 minutes, and then the monomer solution (ii) was added dropwise over 20 minutes. . Thereafter, the reaction was further performed for 1 hour, and the mixture was cooled to 30 ° C. or less to obtain a copolymer liquid. The obtained copolymer solution was concentrated to 150 g and then transferred to a separatory funnel. To this separatory funnel, 50 g of methanol and 400 g of n-hexane were added for separation and purification. After separation, the lower layer solution was recovered. The recovered lower layer solution was replaced with 4-methyl-2-pentanol to obtain a resin solution. Mw of the copolymer contained in the obtained resin solution was 5,730, Mw / Mn was 1.23, and the yield was 26%. Moreover, the content rate (mol%) of the structural unit derived from a compound (M-10) and a compound (M-14) is 50.3: 49.7, respectively, and a fluorine atom content rate is 43.6%. there were. This copolymer is referred to as “upper layer polymer (G-1)”.

[Synthesis Example 8]
A monomer solution in which 46.95 g (85 mol%) of the compound (M-14) and 6.91 g of 2,2′-azobis- (methyl 2-methylpropionate) were dissolved in 100 g of isopropyl alcohol was prepared. On the other hand, 50 g of isopropyl alcohol was put into a 500 mL three-necked flask equipped with a thermometer and a dropping funnel, and purged with nitrogen for 30 minutes. After purging with nitrogen, the inside of the flask was heated to 80 ° C. while stirring with a magnetic stirrer. Using a dropping funnel, a monomer solution prepared in advance was added dropwise over 2 hours.
After completion of the dropwise addition, the reaction was further continued for 1 hour, 10 g of an isopropyl alcohol solution of 3.05 g (15 mol%) of the compound (M-15) was dropped over 30 minutes, and then the reaction was further performed for 1 hour. It cooled to 30 degrees C or less, and the copolymer liquid was obtained. The obtained copolymer solution was concentrated to 150 g and then transferred to a separatory funnel. The separatory funnel was charged with 50 g of methanol and 600 g of n-hexane to carry out separation and purification. After separation, the lower layer solution was recovered. This lower layer solution was diluted with isopropyl alcohol to 100 g, and again transferred to a separatory funnel. 50 g of methanol and 600 g of n-hexane were put into a separatory funnel, separation and purification were performed, and the lower layer liquid was recovered after separation. The recovered lower layer solution was replaced with 4-methyl-2-pentanol, and the total amount was adjusted to 250 g. After the adjustment, 250 g of water was added for separation and purification. After separation, the upper layer liquid was recovered.
The recovered upper layer liquid was replaced with 4-methyl-2-pentanol to obtain a resin solution. Mw of the copolymer contained in the obtained resin solution was 9,760, Mw / Mn was 1.51, and the yield was 65%. Moreover, the content rate (mol%) of the structural unit derived from the compound (M-14) and the compound (M-15) was 95: 5, respectively, and the fluorine atom content rate was 36.8%. This copolymer is referred to as “upper layer polymer (G-2)”.

<Preparation of upper layer film-forming composition>
[Synthesis Example 9]
Polymer (G-1) 7 parts by mass, (G-2) 93 parts by mass, diethylene glycol monoethyl ether acetate 10 parts by mass, 4-methyl-2-hexanol 10 parts by mass and diisoamyl ether 90 parts by mass By mixing, an upper layer film-forming composition was prepared.

<Preparation of radiation-sensitive resin composition>
[Example 3]
[B] An amount corresponding to 100 parts by mass in terms of polymer (B-1) is taken, and [A] (A-1) as an acid generator is contained in an amount of 8.9 parts by mass, and [D] is contained. 0.9 parts by mass of (D-1) as a nitrogen organic compound, 30 parts by mass of (F-1) as an additive [F], and (E-1) 1,250 parts by mass as an [E] solvent And (E-2) 520 parts by mass were mixed and filtered through a filter to prepare a radiation-sensitive resin composition.

[Examples 4-31 and Comparative Examples 1-29]
A radiation-sensitive resin composition was prepared in the same manner as in Example 1 except that each type and amount of components shown in Table 1 were used. In Table 1, “-” indicates that the corresponding component was not used.

  The detail of the [D]-[F] component used by the Example and the comparative example is shown.

<[D] Nitrogen-containing compound>
D-1: 4-hydroxy-Nt-amyloxycarbonylpiperidine

D-2: 2,6-diisopropylaniline

D-3: 2-Phenylbenzimidazole

D-4: Triphenylsulfonium salicylate

D-5: Triphenylsulfonium camphorsulfonate

<[E] solvent>
E-1: Propylene glycol monomethyl ether acetate E-2: Cyclohexanone

<[F] Localization promoter>
F-1: γ-butyrolactone

<Pattern formation>
[P-1]
A lower antireflection film having a thickness of 77 nm was formed on the surface of an 8-inch silicon wafer by using a lower antireflection film forming agent (ARC29A, Nissan Chemical Co., Ltd.). A radiation sensitive resin composition was applied to the surface of this substrate by spin coating, and soft baking (SB) was performed on a hot plate at 120 ° C. for 60 seconds to form a photoresist film having a thickness of 120 nm. This photoresist film was exposed through a mask pattern using a full field reduction projection exposure apparatus full field reduction projection exposure apparatus (NSRS306C, NIKON). Thereafter, post-exposure baking (PEB) was performed at 90 ° C. for 60 seconds, followed by development with a 2.38% tetramethylammonium hydroxide aqueous solution (TMAH) at 25 ° C. for 30 seconds, washing with water, and drying. The resist pattern was formed. At this time, the exposure amount for forming a 1: 1 line and space having a line width of 90 nm through a mask of 90 nm line and 180 nm pitch was determined as the optimum exposure amount. A scanning electron microscope (S-9380, Hitachi High-Technologies Corporation) was used for length measurement. This pattern forming method is defined as (P-1).

[P-2]
A 75 nm-thick photoresist film is formed with a radiation-sensitive resin composition on a 12-inch silicon wafer on which a lower antireflection film is formed in the same manner as in the pattern formation method (P-1), and SB is performed at 120 ° C. for 60 seconds. Went. Next, the upper layer film-forming composition was spin-coated on the formed photoresist film, and post-baked (PB) at 90 ° C. for 60 seconds to form an upper layer film having a thickness of 90 nm. Thereafter, using an ArF excimer laser immersion exposure apparatus (NSR S610C, NIKON), exposure was performed through a mask pattern under the conditions of NA = 1.3, ratio = 0.800, and annular. After the exposure, PEB was performed at 90 ° C. for 60 seconds. Thereafter, the resist was developed with a 2.38% TMAH aqueous solution, washed with water, and dried to form a positive resist pattern. At this time, an exposure amount for forming a 1: 1 line and space having a line width of 50 nm through a mask of 50 nm line and 100 nm pitch was determined as the optimum exposure amount. For the measurement, a scanning electron microscope (CG-4000, Hitachi High-Technologies Corporation) was used. This pattern forming method is defined as (P-2).

[P-3]
A 75 nm-thick photoresist film is formed with a radiation-sensitive resin composition on a 12-inch silicon wafer on which a lower antireflection film is formed in the same manner as in the pattern formation method (P-1), and SB is performed at 120 ° C. for 60 seconds. Went. Next, the photoresist film was exposed through a mask pattern using the ArF excimer laser immersion exposure apparatus under the conditions of NA = 1.3, ratio = 0.800, and annular. After the exposure, PEB was performed at 90 ° C. for 60 seconds. Thereafter, the resist was developed with a 2.38% TMAH aqueous solution, washed with water, and dried to form a positive resist pattern. At this time, an exposure amount for forming a 1: 1 line and space having a line width of 50 nm through a mask of 50 nm line and 100 nm pitch was determined as the optimum exposure amount. For the measurement, a scanning electron microscope (CG-4000, Hitachi High-Technologies Corporation) was used. This pattern forming method is defined as (P-3).

<Evaluation of MEEF>
When the pattern forming method was (P-1), LS patterns were formed through mask patterns having a pitch of 86 nm line 180 nm, 88 nm line 180 nm, 90 nm line 180 nm, 92 nm line 180 nm, and 94 nm line 180 nm.
When the pattern forming method is (P-2) and (P-3), the mask pattern is set to 48 nm line 100 nm, 49 nm line 100 nm pitch, 50 nm line 100 nm pitch, 51 nm line 100 nm pitch, 52 nm line 100 nm pitch, respectively. An LS pattern was formed.
At this time, the slope of the straight line when the line size (nm) of the mask was plotted on the horizontal axis and the line width (nm) formed on the resist film using each mask pattern was plotted on the vertical axis was calculated as MEEF. As the MEEF (straight line) is closer to 1, the mask reproducibility is better. The results are shown in Table 1.

The examples and comparative examples in Table 1 will be described. Example 3 and Comparative Example 1 correspond to each other (the acid generator component is different as a major difference). Similarly, Examples 4 to 31 are comparative examples 2 respectively. ~ 29 correspond to each other.
When each example was compared with a comparative example corresponding thereto, it was found that a resist pattern formed using the radiation-sensitive resin composition can reduce MEEF.

  According to the present invention, a radiation-sensitive resin composition that sufficiently satisfies not only basic characteristics such as sensitivity and resolution, but also MEEF performance, a forming method for forming a resist pattern from the composition, and the composition A compound that can be suitably used as a material can be provided. In addition, the composition can be suitably used in an immersion exposure method or the like.

Claims (9)

[A] an acid generator represented by the following formula (1), and [B] (b1) a radiation sensitive polymer containing a polymer having a structural unit whose solubility in an alkaline developer is increased or decreased by the action of an acid. Resin composition.

(In Formula (1), R ¹ is a monovalent organic group. Y is a divalent organic group having 1 to 15 carbon atoms, provided that hydrogen contained in the divalent organic group having 1 to 15 carbon atoms. Some or all of the atoms may be substituted. A ⁺ is a cation.) [A] The radiation sensitive resin composition according to claim 1, wherein the acid generator is represented by the following formula (2).

(In the formula (2),
R ¹ is an aliphatic group having 1 to 20 carbon atoms which may contain an oxygen atom. However, some or all of the hydrogen atoms may be substituted.
Y is an alkanediyl group having 1 to 10 carbon atoms in which at least one fluorine atom is bonded to a terminal carbon atom bonded to a sulfur atom.
R ² and R ³ are each independently a chain aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, and an alicyclic hydrocarbon group having 3 to 20 carbon atoms. is there. R ⁴ is a phenyl group or a naphthyl group. However, some or all of the hydrogen atoms contained in the groups represented by R ² , R ³ and R ⁴ are a halogen atom, a hydroxyl group, a cyano group, an alkoxyl group, an alkyl group having 1 to 10 carbon atoms, an aryl group, Alternatively, it may be substituted with an aralkyl group. In addition, these substituents are included in the skeleton chain: —O—CO—, —CO—O—, —SO ₂ —, —SO ₃ —, —O—, —NR ⁵ —CO—, —CO—NR ⁵ —. May be included.
R ⁵ is an alkyl group having 1 to ⁵ carbon atoms, an aryl group, or an aralkyl group. However, some or all of the hydrogen atoms contained in these groups may be substituted with halogen atoms. )   [B] The radiation sensitive resin composition according to claim 1 or 2, wherein the polymer further comprises (b2) a structural unit containing a lactone skeleton or a cyclic carbonate skeleton.   [B] The radiation-sensitive resin composition according to claim 1, 2 or 3, wherein the polymer further comprises (b3) a structural unit containing a polar group.   [C] The radiation sensitive resin composition according to any one of claims 1 to 4, further comprising a polymer having a fluorine atom.   [D] The radiation sensitive resin composition according to any one of claims 1 to 5, further comprising a nitrogen-containing organic compound. (I) The process of apply | coating the radiation sensitive resin composition of any one of Claims 1-6 to a board | substrate, and forming a resist film,
(Ii) a pattern forming method including a step of exposing the resist film, and (iii) an alkali developing step of the exposed resist film. A compound represented by the following formula (1).

(In Formula (1), R ¹ is a monovalent organic group. Y is a divalent organic group having 1 to 15 carbon atoms, provided that hydrogen contained in the divalent organic group having 1 to 15 carbon atoms. Some or all of the atoms may be substituted. A ⁺ is a cation.) A compound represented by the following formula (2).

(In the formula (2),
R ¹ is an aliphatic group having 1 to 20 carbon atoms which may contain an oxygen atom. However, some or all of the hydrogen atoms may be substituted.
Y is an alkanediyl group having 1 to 10 carbon atoms in which at least one fluorine atom is bonded to a terminal carbon atom bonded to a sulfur atom.
R ² and R ³ are each independently a chain aliphatic hydrocarbon group having 1 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, and an alicyclic hydrocarbon group having 3 to 20 carbon atoms. is there. However, some or all of the hydrogen atoms contained in these groups may be substituted with a halogen atom, a hydroxyl group, a cyano group, an alkoxyl group, an alkyl group having 1 to 10 carbon atoms, an aryl group, or an aralkyl group. In addition, these substituents are included in the skeleton chain: —O—CO—, —CO—O—, —SO ₂ —, —SO ₃ —, —O—, —NR ⁵ —CO—, —CO—NR ⁵ —. May be included.
R ⁵ is an alkyl group having 1 to ⁵ carbon atoms, an aryl group, or an aralkyl group. However, some or all of the hydrogen atoms contained in these groups may be substituted with halogen atoms.
R ⁴ is a phenyl group or a naphthyl group. )