JP4810862B2 - Onium salt, radiation-sensitive acid generator and positive radiation-sensitive resin composition using the same - Google Patents

Description

  The present invention is a resist material suitably used in the field of microfabrication including the manufacture of integrated circuit elements, particularly an acid group having at least a part of the acid group protected by an acid dissociable group. A chemical amplification type utilizing a chemical amplification effect between an acid-dissociable group-modified alkali-soluble resin and a radiation-sensitive acid generator that generates acid upon irradiation with short-wavelength radiation such as deep ultraviolet rays, X-rays, and electron beams The present invention relates to a radiation sensitive resin composition. More specifically, the present invention relates to an onium salt that can form a resist pattern with high resolution when used as a radiation-sensitive acid generator.

In recent years, in the field of microfabrication including the manufacture of integrated circuit elements, it is possible to perform microfabrication at a level of 0.1 μm or less (submicron order) in order to manufacture elements with higher integration. There is a need for lithographic techniques. In order to process a fine pattern, it is known that it is effective to draw a pattern using radiation having a shorter wavelength, and instead of the conventionally used visible light and ultraviolet light, far ultraviolet light is used. , X-ray, electron beam and other short-wavelength radiation, more specifically, KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), EUV (Extreme Ultra-Violet : Extreme ultraviolet rays, wavelength of 13 nm, etc.) or use of electron beams or the like has been studied.

  Lithographic techniques using short-wavelength radiation as described above include acid-dissociable group-modified alkali-soluble resins having an acid group and at least part of the acid group being protected by an acid-dissociable group, Chemical amplification type radiation-sensitive resin using chemical amplification effect between radiation-sensitive acid generator that generates acid upon irradiation (exposure) of wavelength radiation (simply referred to as “acid generator”) A technique for forming a resist pattern using a composition has been proposed.

  The chemically amplified radiation-sensitive resin composition generates an acid from an acid generator by exposure, dissociates an acid-dissociable group that protected the acidic group of the alkali-soluble resin by the action of the acid, and the alkali-soluble resin This is a composition for forming a resist pattern by exposing the acidic group of the material and making the exposed region easily soluble in an alkali developer.

  For example, a polymer having a carboxyl group (acidic group) protected with a t-butyl group (acid-dissociable group) or a polymer having a phenolic hydroxyl group (acidic group) protected with a t-butoxycarbonyl group (acid-dissociable group) A resist composition containing an acid generator such as a diaryl iodonium salt or a triaryl sulfonium salt is disclosed (for example, see Patent Document 1).

  A resist composition containing a compound in which an amide group or the like is introduced into the aryl group or the like of the triarylsulfonium salt as described above is also disclosed as an acid generator (see, for example, Patent Document 2).

JP 59-45439 A JP 2003-307839 A

  The resist composition described in Patent Document 1 generates an acid from a diaryliodonium salt or the like by exposure, dissociates a t-butyl group or the like that protected the carboxyl group of the alkali-soluble resin by the action of the acid, A resist pattern can be formed by exposing the carboxyl group of the soluble resin and making the exposed region easily soluble in an alkali developer. However, this resist composition has a problem of low sensitivity to short wavelength radiation. Although it is conceivable to improve the sensitivity by using a triarylsulfonium salt as the acid generator, the triarylsulfonium salt has low base resistance, and the type and amount of the acid diffusion inhibitor used together are limited. In that respect, there was still room for improvement.

  In addition, the resist composition described in Patent Document 2 introduces an amide group or the like into the aryl group or the like of the triarylsulfonium salt of the acid generator, thereby improving sensitivity, resolution, There is an advantage that the profile and the like are improved. However, in recent years, the high integration of integrated circuit elements has been progressing rapidly, so that in the field of microfabrication, a resist having excellent resolving power that can form a resist pattern with higher definition than before. There is a need for materials. Considering such a situation, the resist composition described in Patent Document 2 is still not fully satisfactory in terms of resolution, and further improvement has been demanded.

  As described above, at present, a sufficiently satisfactory high resolution, for example, a high resolution capable of forming a resist pattern of less than 0.13 μm with a KrF excimer laser and less than 0.11 μm with an ArF excimer laser can be obtained. The resist material has not yet been disclosed. Therefore, in the field of microfabrication, especially lithography, it has become an important issue to create a resist material that can obtain a high resolution that can cope with the high definition of resist patterns in recent years.

  The present invention has been made in order to solve the above-described problems of the prior art, and a novel onium salt having a chemical structure different from that of the conventional one, and the onium salt using the onium salt are further improved than before. The present invention relates to a radiation sensitive acid generator and a radiation sensitive resin composition capable of forming a high-definition resist pattern.

As a result of intensive studies to solve the problems of the prior art as described above, the present inventors solved the problem by introducing triphenylsulfonium salt as a basic skeleton and introducing a cyano group into the aromatic ring. The present invention has been completed. Specifically, according to the present invention, the following onium salt, a radiation sensitive acid generator and a positive radiation sensitive resin composition using the same are provided.

〔一般式（１）において、Ａは硫黄原子、Ａｒ¹は各々が同一若しくは異なった、炭素数６〜２０の芳香族炭化水素基、Ａｒ²は各々が同一若しくは異なった、炭素数６〜２０の芳香族炭化水素基、Ｂは下記一般式（ｉ）で示される構造を示し、Ｙ^-はスルホン酸アニオンを示す。ｍは１〜３の整数、ｎは０〜２の整数（但し、ｍ＋ｎ＝３）、ｘは１〜２の整数である。〕
Ｚ−Ｂ' …（ｉ）
〔一般式（ｉ）において、Ｚは酸素原子、Ｂ'はメチレン基又はアルキレン基を示す。〕 [1] An onium salt represented by the following general formula (1).

[In General Formula (1), A is a sulfur atom, Ar ¹ is the same or different and each is an aromatic hydrocarbon group having 6 to 20 carbon atoms, Ar ² is the same or different, each having 6 to 20 carbon atoms aromatic hydrocarbon group, B represents a structure represented by the following general formula (i), Y ^- represents a sulfonate anion. m is an integer of 1 to 3, n is an integer of 0 to 2 (where m + n = 3), and x is an integer of 1 to 2. ]
Z-B '(i)
[In General Formula (i), Z represents an oxygen atom , and B ′ represents a methylene group or an alkylene group. ]

[ 2 ] A radiation-sensitive acid generator containing at least one onium salt according to [1] .

[ 3 ] An acid-dissociable group-modified alkali-soluble resin (component A) having an acidic group and at least a part of the acidic group protected by an acid-dissociable group, and a radiation-sensitive acid generator (component B) Is a positive radiation sensitive resin composition containing at least one onium salt according to [1] as the B component.

[ 4 ] The positive radiation sensitive resin composition according to [3], further including an acid diffusion inhibitor (C component) as a constituent component.

  The onium salt, the radiation-sensitive acid generator and the positive radiation-sensitive resin composition of the present invention can obtain sufficiently satisfactory high resolution and good storage stability. For example, it exhibits excellent resolving power that can form a high-definition resist pattern such as less than 0.13 μm with a KrF excimer laser and less than 0.11 μm with an ArF excimer laser.

  Hereinafter, the best mode for carrying out the onium salt, the radiation sensitive acid generator and the positive radiation sensitive resin composition of the present invention will be specifically described. However, the present invention includes all embodiments including the invention-specific matters, and is not limited to the embodiments described below.

〔一般式（１）において、Ａは硫黄原子、Ａｒ¹は各々が同一若しくは異なった、炭素数６〜２０の芳香族炭化水素基、Ａｒ²は各々が同一若しくは異なった、炭素数６〜２０の芳香族炭化水素基、Ｂは下記一般式（ｉ）で示される構造を示し、Ｙ^-はスルホン酸アニオンを示す。ｍは１〜３の整数、ｎは０〜２の整数（但し、ｍ＋ｎ＝３）、ｘは１〜２の整数である。〕
Ｚ−Ｂ' …（ｉ）
〔一般式（ｉ）において、Ｚは酸素原子、Ｂ'はメチレン基又はアルキレン基を示す。〕 [1] Onium salt:
The onium salt of the present invention is represented by the following general formula (1).

[In General Formula (1), A is a sulfur atom, Ar ¹ is the same or different and each is an aromatic hydrocarbon group having 6 to 20 carbon atoms, Ar ² is the same or different, each having 6 to 20 carbon atoms aromatic hydrocarbon group, B represents a structure represented by the following general formula (i), Y ^- represents a sulfonate anion. m is an integer of 1 to 3, n is an integer of 0 to 2 (where m + n = 3), and x is an integer of 1 to 2. ]
Z-B '(i)
[In General Formula (i), Z represents an oxygen atom , and B ′ represents a methylene group or an alkylene group. ]

In the general formula (1), examples of the “ aromatic hydrocarbon group having 6 to 20 carbon atoms ” represented by “Ar ¹ ” to “Ar ² ” include a phenyl group, a toluyl group, a benzyl group, a methylbenzyl group, A xylyl group, a mesityl group, a naphthyl group, an anthryl group, etc. can be mentioned.

Among the aromatic hydrocarbon groups , a phenyl group, a naphthyl group, and an anthryl group are preferable, and a phenyl group is more preferable because the effect of improving the light absorbency with respect to the irradiation light of the KrF or ArF excimer laser is high.

The onium salt of the present invention has the above triphenylsulfonium salt as a basic skeleton and a cyano group introduced into the aromatic ring. By introducing an electron-withdrawing cyano group, it is possible to obtain an acid diffusion suppression effect (specifically, an effect of suppressing the problem of reduced resolution caused by the generated acid), and as a result, a sufficiently high resolution And good storage stability can be obtained.

In the general formula (i), the “ alkylene group” represented by “B ′” is a 1,1-ethylene group, a 1,2-ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, hexa C2-C8 alkylene groups, such as a methylene group, etc. are mentioned.

The methylene group or alkylene group may be one in which some or all of the hydrogen atoms are substituted with substituents. Examples of the substituent include a hydroxyl group, a carboxyl group, a cyano group, a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, a 2-methylpropoxy group, and a 1-methylpropoxy group. An alkoxyl group having 1 to 4 carbon atoms such as t-butoxy group; an alkylcarbonyloxy group having 2 to 5 carbon atoms such as methylcarbonyloxy group, ethylcarbonyloxy group and t-butylcarbonyloxy group; methoxycarbonyl group, ethoxy An alkoxycarbonyl group having 2 to 5 carbon atoms such as a carbonyl group and a t-butoxycarbonyl group; an alkoxycarbonylalkoxy group having 3 to 6 carbon atoms such as a methoxycarbonylmethoxy group, an ethoxycarbonylmethoxy group and a t-butoxycarbonylmethoxy group; fluorine Atoms, halogen atoms such as chlorine atoms, etc. It is.

In the methylene group or alkylene group , part or all of the hydrogen atoms may be substituted with one kind of substituent, or may be substituted with two or more kinds of substituents.

In the onium salt of the present invention, “B ′” in the general formula (i) is a methylene group or an alkylene group . In other words, it has a structure in which a methylene group or an alkylene group is interposed between an aromatic ring and a cyano group, and the aromatic ring and the cyano group are bonded via these. With such a structure, the basicity of the cyano group can be controlled by the kind of the methylene group or alkylene group , and a desired level of acid diffusion suppression effect can be obtained.

In the general formula (1), “B” has a structure represented by the following general formula (i). That is, it is a structure in which a cyano group is bonded to an aromatic hydrocarbon group via an oxygen atom . In such a structure, the onium salt is stabilized and the cyano group is less likely to be detached from the onium salt skeleton, compared to a structure in which the cyano group is bonded to the aromatic hydrocarbon group without an oxygen atom. There is an advantage that the effect of suppressing diffusion is improved.
Z-B '(i)
[In General Formula (i), Z represents an oxygen atom , and B ′ represents a methylene group or an alkylene group. ]

Furthermore, “B ′” is a methylene group or an alkylene group. That is, when “B ′” is a methylene group or an alkylene group, the structure of “ZB ′” is “methylene group or alkylene group” as a basic skeleton, and one bond is bonded to —O—. The group which was made can be mentioned .

In the general formula (1), “A” represents a sulfur atom . That is, the onium salt of the present invention is a sulfonium salt in which “A” is a sulfur atom . The sulfonium salt has a high effect of improving storage stability .

In the general formula (1), “m” is an integer of 1 to 3, “n” is an integer of 0 to 2, and the sum of “m” and “n” is 3. That is, the sulfonium salt in which “A” is a sulfur atom has three aromatic hydrocarbon groups, and it is sufficient that a cyano group is introduced into at least one of the aromatic hydrocarbon groups. . Moreover, since “x” in the general formula (1) is an integer of 1 or 2 , it is sufficient that at least one cyano group is introduced to one aromatic hydrocarbon group or the like.

In the general formula (1), "Y ^-" in as "acid anion" represented, in _{^{particular, CH 3 SO 3 -, C}} 4 H 9 SO 3 -, C 8 H 17 SO 3 -, p _{-CH 3 C 6 H 4 SO 3} -, CF 3 SO 3 -, C 4 F 9 SO 3 -, C 8 H 9 SO 3 - and the like. Among these, CF ₃ SO ₃ ⁻ and C ₄ F ₉ SO ₃ ^— are preferable because of high acidity.

Hereinafter, general formulas (I) to ( VII ) showing specific chemical structures of preferred embodiments of the onium salts of the present invention are exemplified in Table 1. In Table 1, only the cation portion of the onium salt is shown.

〔前記反応式において、Ａ、Ａｒ¹、Ａｒ²、Ｙ^-、Ｚ¹、Ｂ、ｍ、ｎ、ｘは前記の定義通りである。Ｘはヨウ素原子、臭素原子又は塩素原子を示す。〕 The onium salt (1) of the present invention includes, for example, an onium salt having a Z ¹ —H group represented by the following general formula (2) and a halide of a nitrile represented by the following general formula (3) (hereinafter referred to as “nitrile”). The compound can be synthesized in the presence of a suitable base.

[In the above reaction formula, A, Ar ¹ , Ar ² , Y ⁻ , Z ¹ , B, m, n, x are as defined above]. X represents an iodine atom, a bromine atom or a chlorine atom. ]

  The molar ratio of the nitrile halide (3) to the onium salt (2) is usually 1 to 100, preferably 1.5 to 10.

  Examples of the base used for the reaction include triethylamine, pyridine, potassium hydroxide, sodium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate and the like. Among these, potassium carbonate is preferable because it has moderate basicity. The molar ratio of the base to the nitrile halide (3) is usually 1.0 to 10.0, preferably 2.0 to 4.0.

  This reaction is performed in an aprotic organic solvent such as toluene, tetrahydrofuran, methylene chloride, pyridine, DMF, DMSO, acetone or the like. The use ratio of the organic solvent is usually 5 to 100 parts by mass, preferably 10 to 100 parts by mass, and preferably 20 to 90 parts by mass with respect to 100 parts by mass in total of the organic solvent and water. Is more preferable.

  The reaction temperature is usually −40 to 50 ° C., preferably −20 to 30 ° C. Moreover, reaction time is 0.1 to 72 hours normally, and it is preferable to set it as 0.5 to 3 hours.

[2] Positive radiation sensitive resin composition:
The positive radiation sensitive resin composition of the present invention is a composition containing an acid dissociable group-modified alkali-soluble resin (component A) and a radiation sensitive acid generator (component B) as essential components.

[2-A] Acid-dissociable group-modified alkali-soluble resin (component A):
The “acid-dissociable group-modified alkali-soluble resin” is a resin having an acidic group and at least a part of the acidic group being protected by the acid-dissociable group. This resin exhibits alkali insolubility or alkali insolubility in a state where at least part of the acid groups in the resin is protected by the acid dissociable group. However, when the acid dissociable group is dissociated by the action of an acid, the acid group is It is a resin that is exposed and exhibits alkali solubility.

  Here, “alkali insoluble or hardly alkali soluble” is obtained by a radiation sensitive resin composition containing an acid dissociable group-modified alkali soluble resin (component A) and a radiation sensitive acid generator (component B). When a film obtained only with an acid-dissociable group-modified alkali-soluble resin is developed instead of the resist film under the alkali development conditions used when forming a resist pattern from the resist film formed, the initial film of the film It means that 50% or more of the thickness remains after development.

  The “acidic group” is not particularly limited as long as it is a functional group exhibiting acidity. For example, a phenolic hydroxyl group, a carboxyl group, a sulfonic acid group, etc. are mentioned. Among these, a phenolic hydroxyl group and a carboxyl group are preferable because the effect of improving the solubility in alkali is high. Of these, the acid-dissociable group-modified alkali-soluble resin may have only one acidic group, or may have two or more acidic groups.

  Examples of the “acid dissociable group” include a substituted methyl group, 1-substituted ethyl group, 1-substituted n-propyl group, 1-branched alkyl group, silyl group, germyl group, alkoxycarbonyl group, acyl group, and Examples include cyclic acid dissociable groups.

  More specifically, examples of the “substituted methyl group” include a methoxymethyl group, a methylthiomethyl group, an ethoxymethyl group, an ethylthiomethyl group, a methoxyethoxymethyl group, a benzyloxymethyl group, a benzylthiomethyl group, and a phenacyl group. 4-bromophenacyl group, 4-methoxyphenacyl group, 4-methylthiophenacyl group, α-methylphenacyl group, cyclopropylmethyl group, benzyl group, diphenylmethyl group, triphenylmethyl group, 4-bromobenzyl group, 4-nitrobenzyl group, 4-methoxybenzyl group, 4-methylthiobenzyl group, 4-ethoxybenzyl group, 4-ethylthiobenzyl group, piperonyl group, methoxycarbonylmethyl group, ethoxycarbonylmethyl group, n-propoxycarbonylmethyl group I-propoxycarbonyl me Le group, n- butoxycarbonyl methyl group, and the like t- butoxycarbonyl methyl group.

  Examples of the “1-substituted ethyl group” include 1-methoxyethyl group, 1-methylthioethyl group, 1,1-dimethoxyethyl group, 1-ethoxyethyl group, 1-ethylthioethyl group, 1,1-diethyl Ethoxyethyl group, 1-phenoxyethyl group, 1-phenylthioethyl group, 1,1-diphenoxyethyl group, 1-benzyloxyethyl group, 1-benzylthioethyl group, 1-cyclopropyloxyethyl group, 1- Cyclohexyloxyethyl group, 1-phenylethyl group, 1,1-diphenylethyl group, 1-methoxycarbonylethyl group, 1-ethoxycarbonylethyl group, 1-n-propoxycarbonylethyl group, 1-i-propoxycarbonylethyl group 1-n-butoxycarbonylethyl group, 1-t-butoxycarbonylethyl group and the like.

  Examples of the “1-substituted-n-propyl group” include 1-methoxy-n-propyl group and 1-ethoxy-n-propyl group, and the “1-branched alkyl group” includes, for example, i-propyl. Group, sec-butyl group, t-butyl group, 1,1-dimethylpropyl group, 1-methylbutyl group, 1,1-dimethylbutyl group and the like.

  Examples of the “silyl group” include trimethylsilyl group, ethyldimethylsilyl group, methyldiethylsilyl group, triethylsilyl group, i-propyldimethylsilyl group, methyldi-i-propylsilyl group, tri-i-propylsilyl group, t -Butyldimethylsilyl group, methyldi-t-butylsilyl group, tri-t-butylsilyl group, phenyldimethylsilyl group, methyldiphenylsilyl group, triphenylsilyl group and the like.

  Examples of the “germyl group” include trimethylgermyl group, ethyldimethylgermyl group, methyldiethylgermyl group, triethylgermyl group, i-propyldimethylgermyl group, methyldi-i-propylgermyl group, tri- Examples include i-propylgermyl group, t-butyldimethylgermyl group, methyldi-t-butylgermyl group, tri-t-butylgermyl group, phenyldimethylgermyl group, methyldiphenylgermyl group, and triphenylgermyl group. .

  Examples of the “alkoxycarbonyl group” include methoxycarbonyl group, ethoxycarbonyl group, i-propoxycarbonyl group, t-butoxycarbonyl group and the like.

  Examples of the “acyl group” include acetyl group, propionyl group, butyryl group, heptanoyl group, hexanoyl group, valeryl group, pivaloyl group, isovaleryl group, laurylyl group, myristoyl group, palmitoyl group, stearoyl group, oxalyl group, malonyl group , Succinyl group, glutaryl group, adipoyl group, piperoyl group, suberoyl group, azelaoil group, sebacoyl group, acryloyl group, propioyl group, methacryloyl group, crotonoyl group, oleoyl group, maleoyl group, fumaroyl group, mesaconoyl group, camphoroyl group, Benzoyl, phthaloyl, isophthaloyl, terephthaloyl, naphthoyl, toluoyl, hydroatropoyl, atropoyl, cinnamoyl, furoyl, thenoyl, nicotinoyl, Nicotinoyl group, p- toluenesulfonyl group, mesyl group, and the like.

  Examples of the “cyclic acid dissociable group” include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclohexenyl group, a 4-methoxycyclohexyl group, a tetrahydropyranyl group, a tetrahydrofuranyl group, a tetrahydrothiopyranyl group, and a tetrahydrothio group. Examples include furanyl group, 3-bromotetrahydropyranyl group, 4-methoxytetrahydropyranyl group, 4-methoxytetrahydrothiopyranyl group, 3-tetrahydrothiophene-1,1-dioxide group.

  Among these “acid-dissociable groups”, benzyl group, t-butoxycarbonylmethyl group, 1-methoxyethyl group, 1-ethoxyethyl group, 1-cyclohexyloxyethyl group, 1-ethoxy-n-propyl group, A t-butyl group, 1,1-dimethylpropyl group, trimethylsilyl group, t-butoxycarbonyl group, tetrahydropyranyl group, tetrahydrofuranyl group, tetrahydrothiopyranyl group, tetrahydrothiofuranyl group and the like are preferable.

  The acid-dissociable group-modified alkali-soluble resin may have an acidic group protected by only one acid-dissociable group among the acid-dissociable groups, or two or more acid-dissociable groups acidic. It may be protected by a group.

  In the acid-dissociable group-modified alkali-soluble resin, it is sufficient that at least a part of the acidic group is protected by the acid-dissociable group, and it is not necessary that all of the acidic groups are protected by the acid-dissociable group. The rate of introduction of acid dissociable groups (ratio of the number of acid dissociable groups to the total number of acid groups and acid dissociable groups in the acid dissociable group-modified alkali-soluble resin) It depends on the type of resin. However, the introduction rate is preferably in the range of 5 to 100%, and more preferably in the range of 10 to 100%.

  The structure of the acid-dissociable group-modified alkali-soluble resin is not particularly limited as long as it has the above-described properties, and various structures can be used as necessary. For example, a resin in which part or all of the hydrogen atoms of the phenolic hydroxyl group in poly (p-hydroxystyrene) are substituted with the acid dissociable group, p-hydroxystyrene and / or p-hydroxy-α-methylstyrene ( Resins in which part or all of the hydrogen atoms of the phenolic hydroxyl group and / or the carboxyl group in the copolymer with (meth) acrylic acid have been substituted with the acid dissociable groups, and the branched structure described later in these resins. The introduced resin or the like can be suitably used.

  In addition, the structure of the acid-dissociable group-modified alkali-soluble resin can be various structures depending on the type of radiation used. For example, when a KrF excimer laser is used, the phenolic hydroxyl group contained in the repeating unit represented by the following general formula (4) and the repeating unit represented by the following general formula (4) is protected with the acid dissociable group. An alkali-insoluble (hard) soluble resin (hereinafter, also referred to as “resin (A1)”) containing the above repeating unit is preferable.

〔一般式（４）において、Ｒ⁴は水素原子又は一価の有機官能基を示す。ａ及びｂは１〜３の整数を示す。〕

[In General Formula (4), R ⁴ represents a hydrogen atom or a monovalent organic functional group. a and b show the integer of 1-3. ]

  Examples of the repeating unit represented by the general formula (4) include p-hydroxystyrene, m-hydroxystyrene, o-hydroxystyrene, α-methylhydroxystyrene, 3-methyl-4-hydroxystyrene, 2-methyl-4- Non-aromatic double such as hydroxy styrene, 2-methyl 3-hydroxy styrene, 4-methyl 3-hydroxy styrene, 5-methyl 3-hydroxy styrene, 3,4-dihydroxy styrene, 2,4,6-trihydroxy styrene Examples include units in which the bond is cleaved. Among them, a unit in which a non-aromatic double bond is cleaved such as p-hydroxystyrene, m-hydroxystyrene, o-hydroxystyrene, α-methylhydroxystyrene and the like is preferable.

  Examples of the repeating unit containing an acid dissociable group include a repeating unit in which the phenolic hydroxyl group of the repeating unit represented by the general formula (4) is protected with the acid dissociable group.

  The resin (A1) may further contain other repeating units. Examples of such other repeating units include styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-methoxystyrene, 3-methoxystyrene, 4-methoxystyrene, 4 -T-butoxystyrene, 4-t-butoxycarbonyloxystyrene, 4-t-butoxycarbonylmethyloxystyrene, 4- (2'-t-butoxycarbonylethyloxy) styrene, 4-tetrahydrofuranyloxystyrene, 4-tetrahydro Vinyl aromatic compounds such as pyranyloxystyrene;

  Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, Sec-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, neopentyl (meth) acrylate, n-hexyl (meth) acrylate, 2- (meth) acrylic acid 2- Ethylhexyl, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acryl Norbornyl acid, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate (Meth) acrylic acid dicyclopentenyl, (meth) acrylic acid adamantyl (meth) acrylic acid 2-methyladamantyl, (meth) acrylic acid tetrahydrofuranyl, (meth) acrylic acid tetrahydropyranyl, (meth) acrylic acid phenyl, Benzyl (meth) acrylate, phenethyl (meth) acrylate,

  Unsaturated carboxylic acids such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, cinnamic acid; (meth) acrylic acid 2-carboxyethyl, (meth) acrylic acid 2-carboxypropyl, (meth) acrylic acid Carboxyalkyl esters of unsaturated carboxylic acids such as 3-carboxypropyl; unsaturated nitrile compounds such as (meth) acrylonitrile, α-chloroacrylonitrile, crotonnitrile, maleinonitrile, fumaronitrile; (meth) acrylamide, N, N-dimethyl Unsaturated amide compounds such as (meth) acrylamide, crotonamide, maleamide, and fumaramide; unsaturated imide compounds such as maleimide, N-phenylmaleimide, and N-cyclohexylmaleimide; N-vinyl-ε-caprolactam, N-vinylpyrrolidone, 2- Examples include units in which a polymerizable unsaturated bond such as vinyl pyridine, 3-vinyl pyridine, 4-vinyl pyridine, 2-vinyl imidazole, and 4-vinyl imidazole and other nitrogen-containing vinyl compounds are cleaved.

  Among the other repeating units, styrene, α-methylstyrene, 4-t-butoxystyrene, 4-t-butoxycarbonyloxystyrene, 4-t-butoxycarbonylmethyloxystyrene, 4- (2′-t- Polymerizable unsaturated bonds such as butoxycarbonylethyloxy) styrene, t-butyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, 2-methyladamantyl (meth) acrylate Cleaved units are preferred.

Moreover, when using an ArF excimer laser, an alkali-insoluble (hard) soluble resin (hereinafter also referred to as “resin (A2)”) having a repeating unit represented by the following general formula (5) is preferable. The resin (A2) can also be suitably used for a radiation sensitive resin composition using an F ₂ excimer laser, an electron beam, or the like.

〔一般式（５）において、Ｒ⁶は水素原子又はメチル基を示す。また、各Ｒ⁸は各々が同一若しくは異なった、直鎖状若しくは分岐状のアルキル基（炭素数１〜４）、置換されていてもよい１価の脂環式炭化水素基（炭素数４〜２０）又はいずれか２つのＲ⁸が互いに結合して、それぞれが結合している炭素原子と共に置換されてもよい炭素数４〜２０の２価の脂環式炭化水素基を形成し、残りのＲ⁸が炭素数１〜４の直鎖状若しくは分岐状のアルキル基又は置換されていてもよい１価の脂環式炭化水素基（炭素数４〜２０）である。〕

[In General Formula (5), R ⁶ represents a hydrogen atom or a methyl group. Each R ⁸ is the same or different and is a linear or branched alkyl group (1 to 4 carbon atoms), an optionally substituted monovalent alicyclic hydrocarbon group (4 to 4 carbon atoms). 20) or any two of R ⁸ are bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms which may be substituted together with the carbon atom to which each is bonded, R ⁸ is a linear or branched alkyl group having 1 to 4 carbon atoms or an optionally substituted monovalent alicyclic hydrocarbon group (4 to 20 carbon atoms). ]

〔前記一般式において、Ｒ⁶は水素原子又はメチル基である。〕 Moreover, as a repeating unit represented by the said General formula (5), the repeating unit derived from t-butoxycarbonyl (meth) acrylate and the repeating unit represented by the following general formula are preferable, for example.

[In the above general formula, R ⁶ represents a hydrogen atom or a methyl group. ]

  The resin (A2) may further contain other repeating units. Examples of such other repeating units include norbornene (bicyclo [2.2.1] hept-2-ene), 5-methylbicyclo [2.2.1] hept-2-ene, and 5-ethylbicyclo. [2.2.1] hept-2-ene, 5-hydroxybicyclo [2.2.1] hept-2-ene, 5-fluorobicyclo [2.2.1] hept-2-ene, tetracyclo [4 4.0.12, 5.17,10] dodec-3-ene, 8-methyltetracyclo [4.4.0.12, 5.17,10] dodec-3-ene, 8-ethyltetracyclo [4.4.0.12, 5.17,10] dodec-3-ene, 8-hydroxytetracyclo [4.4.0.12,5.17,10] dodec-3-ene, 8-fluoro Tetracyclo [4.4.0.12,5.17,10] do Monomers having a norbornene skeleton of mosquito-3-ene;

〔一般式（６）において、Ｒ⁶は水素原子又はメチル基である。〕 Acid anhydrides such as maleic anhydride and itaconic anhydride; (meth) acrylic acid represented by the following general formula (6) in addition to the (meth) acrylic acid ester described as the other repeating unit in the resin (A1) Examples thereof include a unit in which a polymerizable unsaturated bond such as an ester is cleaved.

[In General formula (6), R < ⁶ > is a hydrogen atom or a methyl group. ]

  There is no particular limitation on the molecular weight range of the acid-dissociable group-modified alkali-soluble resin, and various molecular weight ranges can be used as necessary. The polystyrene-reduced weight average molecular weight (may be referred to as “Mw”) measured by gel permeation chromatography (GPC) is usually 1000 to 500000, preferably 2000 to 400000, and preferably 3000 to 300000. More preferably. Moreover, in the case of resin which does not have a branched structure, it is more preferable that it is 1000-150,000, and it is especially preferable that it is 3000-100000. In the case of a resin having a branched structure, it is more preferably 5,000 to 500,000, and particularly preferably 8,000 to 300,000. By setting it as such a range, the development characteristic of the resist obtained will be excellent.

  Further, there is no particular limitation on the ratio (Mw / Mn) between the polystyrene-equivalent weight average molecular weight Mw and the polystyrene-equivalent number average molecular weight (may be referred to as “Mn”) measured by GPC, and various molecular weights may be used as necessary. Range. The value of Mw / Mn is usually 1 to 10, preferably 1 to 8, and more preferably 1 to 5. By setting it as such a range, the resolution performance of the obtained resist will be excellent.

  There is no particular limitation on the method for producing the acid dissociable group-modified alkali-soluble resin. For example, in addition to the method of introducing one or more acid-dissociable groups into the acid group in an alkali-soluble resin produced in advance, one or more polymerizable compounds having the acid group protected by the acid-dissociable group A method of polymerizing an unsaturated monomer or one or more polymerizable unsaturated monomers thereof and one or more other polymerizable unsaturated monomers, or the acid protected with the acid dissociable group It can be produced by a method of polycondensing one or more polycondensation components having a group or the one or more polycondensation components and one or more other polycondensation components.

  Here, the one or more polymerizable unsaturated monomers having the acidic group protected by the acid dissociable group, or the one or more polymerizable unsaturated monomers and one or more other polymerizable monomers. In the method of polymerizing with an unsaturated monomer, a polymerization initiator such as a radical polymerization initiator, an anionic polymerization catalyst, a coordination anionic polymerization catalyst, a cationic polymerization catalyst, or a polymerization depending on the type of monomer or reaction medium. The catalyst can be selected appropriately and can be carried out by an appropriate polymerization method such as bulk polymerization, solution polymerization, precipitation polymerization, emulsion polymerization, suspension polymerization, bulk-suspension polymerization. In the method of polycondensing one or more polycondensation components having the acidic group protected by the acid dissociable group or the one or more polycondensation components and one or more other polycondensation components, (Co) polycondensation can be carried out in an aqueous medium or in a mixed medium of water and a hydrophilic solvent in the presence of an acidic catalyst.

[2-B] Radiation sensitive acid generator (component B):
The positive radiation sensitive resin composition of the present invention needs to contain at least one onium salt of the present invention as a radiation sensitive acid generator. Such a composition can obtain a sufficiently satisfactory high resolution, for example, a high resolution capable of forming a resist pattern of less than 0.13 μm with a KrF excimer laser and less than 0.11 μm with an ArF excimer laser.

  Moreover, the positive radiation sensitive resin composition of this invention may contain the radiation sensitive acid generator (B 'component) other than the onium salt of this invention with the onium salt of this invention. Examples of such an acid generator include onium salts other than the onium salt of the present invention and sulfonimide compounds.

  Examples of the “onium salt” include bis (4-t-butylphenyl) iodonium nonafluorobutanesulfonate, bis (4-t-butylphenyl) iodonium trifluoromethanesulfonate, and bis (4-t-butylphenyl) iodonium perfluoro. Octanesulfonate, bis (4-t-butylphenyl) iodonium p-toluenesulfonate, bis (4-t-butylphenyl) iodonium 10-camphorsulfonate, 4-trifluoromethylbenzenesulfonate,

  Bis (4-t-butylphenyl) iodonium perfluorobenzenesulfonate, diphenyliodonium nonafluorobutanesulfonate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium perfluorooctanesulfonate, diphenyliodonium p-toluenesulfonate, diphenyliodoniumbenzenesulfonate, diphenyliodonium10 -Camphorsulfonate, diphenyliodonium 4-trifluoromethylbenzenesulfonate, diphenyliodonium perfluorobenzenesulfonate,

  Bis (p-fluorophenyl) iodonium trifluoromethanesulfonate, bis (p-fluorophenyl) iodonium nonafluoromethanesulfonate, bis (p-fluorophenyl) iodonium camphorsulfonate, (p-fluorophenyl) (phenyl) iodonium trifluoromethanesulfonate,

  Triphenylsulfonium nonafluorobutanesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium perfluorooctanesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfoniumbenzenesulfonate, triphenylsulfonium 10-camphorsulfonate, triphenylsulfonium 4- Trifluoromethylbenzenesulfonate,

  Triphenylsulfonium perfluorobenzenesulfonate, 4-hydroxyphenyl diphenylsulfonium trifluoromethanesulfonate, tri (p-methoxyphenyl) sulfonium nonafluorobutanesulfonate, tri (p-methoxyphenyl) sulfonium trifluoromethanesulfonate, tri (p-methoxyphenyl) ) Sulfonium perfluorooctane sulfonate, tri (p-methoxyphenyl) sulfonium p-toluenesulfonate, tri (p-methoxyphenyl) sulfonium benzene sulfonate, tri (p-methoxyphenyl) sulfonium 10-camphor sulfonate, tris (p-fluorophenyl) ) Sulfonium trifluoromethanesulfonate, tris (p-fluorophenyl) sulfoniu p- toluenesulfonate, include (p- fluorophenyl) such as diphenyl sulfonium trifluoromethanesulfonate.

Examples of the “sulfonimide compound” include compounds represented by the following general formula (7).

  In the general formula (7), V represents a divalent organic functional group such as an alkylene group, an arylene group, and an alkoxylene group. Specifically, a methylene group, an alkylene group having 2 to 20 carbon atoms, an aralkylene group having 2 to 20 carbon atoms, a difluoromethylene group, a perfluoroalkylene group having 2 to 20 carbon atoms, a cyclohexylene group, or a substituted group. Examples thereof include a group having a good norbornane skeleton, a phenylene group, and a group in which an aromatic hydrocarbon group having 2 or more carbon atoms or an alkoxyl group is introduced as a substituent.

In the general formula (7), R ¹⁰ represents a monovalent organic functional group such as an alkyl group, an aromatic hydrocarbon group, a halogen-substituted alkyl group, and a halogen-substituted aromatic hydrocarbon group. Specifically, an alkyl group having 1 to 10 carbon atoms, a perfluoroalkyl group having 1 to 10 carbon atoms, a perfluorocycloalkyl group having 3 to 10 carbon atoms, a bicyclo ring-containing hydrocarbon group having 7 to 15 carbon atoms, A C6-C12 aromatic hydrocarbon group etc. are mentioned. Specifically, alkyl groups such as methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group and n-decyl group; Perfluoroalkyl group such as trifluoromethyl group, pentafluoroethyl group, nonafluoro-n-butyl group, perfluoro-n-octyl group; perfluorocycloalkyl group such as pentafluorocyclohexyl group; alkyl group, alkoxyl group, alkoxy A bicyclo ring-containing hydrocarbon group such as a group having a norbornane skeleton which may be substituted with a carbonyl group, an alkylalkoxycarbonyl group, etc .; a phenyl group, a perfluorophenyl group, a methylphenyl group, a trifluoromethylphenyl group, a tolyl group, An aromatic hydrocarbon group such as a naphthyl group is exemplified.

  Examples of the sulfonimide compound include N- (trifluoromethylsulfonyloxy) succinimide, N- (trifluoromethylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (10-camphorsulfonyloxy) succinimide, N- (10-camphorsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (10-camphorsulfonyloxy) ) -7-oxabicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (p-toluenesulfonyloxy) succinimide, N- (p-toluenesulfonyloxy) bicyclo [2] 2.1] hept-5-ene-2,3-dicarboximide, N- (4-trifluoro) Methylbenzenesulfonyl) succinimide, N-(4-trifluoromethyl benzenesulfonyl oxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide,

  N- (perfluorobenzenesulfonyloxy) succinimide, N- (perfluorobenzenesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluorobutylsulfonyloxy) ) Succinimide, N- (nonafluorobutylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (perfluorooctanesulfonyloxy) succinimide, N- (perfluoro Octanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (benzenesulfonyloxy) succinimide, N- (benzenesulfonyloxy) bicyclo [2.2.1] Hept-5-ene-2,3-dicarboximide, N- ( Nzensulfonyloxy) -7-oxabicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N-{(5-methyl-5-carboxymethanebicyclo [2.2.1] Hept-2-yl) sulfonyloxy} succinimide and the like.

  Among the sulfonimide compounds, N- (trifluoromethylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (10-camphorsulfonyloxy) succinimide, N- (p-toluenesulfonyloxy) succinimide, N- (nonafluorobutylsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (benzenesulfonyloxy) bicyclo [2.2.1] Hept-5-ene-2,3-dicarboximide, N-{(5-methyl-5-carboxymethanebicyclo [2.2.1] hept-2-yl) sulfonyloxy} Succinimide is preferred.

  The mixing ratio of the other acid generator can be appropriately selected according to the type of each acid generator. The mixing ratio of the other acid generator is usually 95 parts by mass or less and 90 parts by mass or less with respect to 100 parts by mass in total of the radiation-sensitive acid generator of the present invention and the other acid generator. It is preferable that the content is 80 parts by mass or less. The blending ratio of the other acid generator is preferably 95 parts by mass or less because the effects (high resolution and storage stability) of the onium salt of the present invention can be sufficiently exhibited. In addition, the said other acid generator may also be used individually by 1 type, and may use 2 or more types together.

  The blending ratio of each component constituting the positive radiation-sensitive resin composition of the present invention can be set in various ranges depending on the characteristics desired to be imparted to the resist. The compounding amount of the radiation sensitive acid generator is usually 0.001 to 70 parts by mass and preferably 0.01 to 50 parts by mass with respect to 100 parts by mass of the acid dissociable group-modified alkali-soluble resin. More preferably, the content is 0.1 to 20 parts by mass. When the blending amount of the radiation sensitive acid generator is 0.001 part by mass or more, it is preferable because deterioration in sensitivity and resolution and deterioration during long-term storage can be suppressed. Moreover, it is preferable to set it as 70 mass parts or less, since it can suppress the resist coating property and the deterioration of the pattern shape.

[2-C] Acid diffusion inhibitor (C component):
In addition to the essential components, an acid diffusion inhibitor may be blended in the positive radiation sensitive resin composition of the present invention. The acid diffusion inhibitor is an additive having an action of controlling a diffusion phenomenon of an acid generated from an acid generator or the like by exposure in a resist film and suppressing an undesirable chemical reaction in a non-exposed region. By blending an acid diffusion inhibitor, the storage stability of the radiation sensitive resin composition can be improved. In addition, by adding an acid diffusion inhibitor, it is possible to improve the resolution of the resist and to suppress changes in the line width of the resist pattern due to fluctuations in the holding time (PED) from exposure to development processing. As a result, there is an advantage that a radiation sensitive resin composition having extremely excellent process stability can be obtained.

  The acid diffusion inhibitor is preferably a nitrogen-containing organic compound whose basicity does not change by exposure or heat treatment during the resist pattern formation step. Examples of the nitrogen-containing organic compound include a compound represented by the following general formula (8) (hereinafter referred to as “nitrogen-containing compound (I)”), a diamino compound having two nitrogen atoms in the same molecule (hereinafter referred to as “nitrogen-containing compound (I)”). , “Nitrogen-containing compound (II)”), amide group-containing compounds, nitrogen-containing heterocyclic compounds, and the like. Among these nitrogen-containing organic compounds, the nitrogen-containing compound (I), the nitrogen-containing compound (II), the nitrogen-containing heterocyclic compound, and the like are preferable. These acid diffusion inhibitors may be used alone or in combination of two or more.

〔一般式（８）において、Ｒ¹²、Ｒ¹⁴及びＲ¹⁶は各々が同一若しくは異なった、水素原子、置換されていてもよいアルキル基、置換されていてもよい芳香族炭化水素基又は置換されていてもよいアラルキル基を示す。〕

[In the general formula (8), R ¹² , R ¹⁴ and R ¹⁶ are the same or different and each represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aromatic hydrocarbon group or a substituted group. An aralkyl group which may be present is shown. ]

  In the general formula (8), as the linear, branched or cyclic alkyl group which may be substituted, an alkyl group having 1 to 15 carbon atoms, preferably an alkyl group having 1 to 10 carbon atoms, such as a methyl group, Ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-pentyl group, neopentyl group, n-hexyl group, texyl group, n -Heptyl group, n-octyl group, n-ethylhexyl group, n-nonyl group, n-decyl group and the like can be mentioned.

  Examples of the optionally substituted aromatic hydrocarbon group include an aromatic hydrocarbon group having 6 to 12 carbon atoms, such as a phenyl group, a tolyl group, a xylyl group, a cumenyl group, and a 1-naphthyl group. . Furthermore, examples of the aralkyl group which may be substituted include an aralkyl group having 7 to 19 carbon atoms, preferably 7 to 13 carbon atoms, such as a benzyl group, an α-methylbenzyl group, a phenethyl group, and a naphthylmethyl group.

  Examples of the nitrogen-containing compound (I) include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; di-n-butylamine, di-n -Dialkylamines such as pentylamine, di-n-hexylamine, di-n-heptylamine, di-n-octylamine, di-n-nonylamine, di-n-decylamine; triethylamine, tri-n-propylamine , Tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, etc. Amines; aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3 Methylaniline, 4-methylaniline, 4-nitroaniline, diphenylamine, triphenylamine, aromatic amines such as 1-naphthylamine; ethanolamine, diethanolamine, alkanolamines such as triethanolamine and the like.

  Examples of the nitrogen-containing compound (II) include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, tetramethylenediamine, hexamethylenediamine, N, N, N ′, N′-tetrakis (2- Hydroxyethyl) ethylenediamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminobenzophenone, 4, 4'-diaminodiphenylamine, 2,2'-bis (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2- (4-aminophenyl) -2- (3-hydroxyphenyl) propane, 2- (4-aminophenyl) -2- (4-hydroxyphenyl) ) Propane, 1,4-bis [1- (4-aminophenyl) -1-methylethyl] benzene, 1,3-bis [1- (4-aminophenyl) -1-methylethyl] benzene and the like. .

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

  Examples of the nitrogen-containing heterocyclic compound include imidazole, benzimidazole, 2-phenylbenzimidazole, 2-methylimidazole, 4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, and 4-methyl-2-phenyl. Imidazoles such as imidazole; pyridine, 2-methylpyridine, 4-methylpyridine, 2-ethylpyridine, 4-ethylpyridine, 2-phenylpyridine, 4-phenylpyridine, N-methyl-4-phenylpyridine, nicotine, nicotine In addition to pyridines such as acid, nicotinamide, quinoline, 8-oxyquinoline and acridine, pyrazine, pyrazole, pyridazine, quinosaline, purine, pyrrolidine, piperidine, 1-piperidineethanol, 2-piperidineethanol, mole Phosphorus, 4-methylmorpholine, piperazine, 1,4-dimethylpiperazine, 1,4-diazabicyclo [2.2.2] octane.

  Moreover, the nitrogen-containing compound which has an acid dissociable group can also be used as said nitrogen-containing organic compound. Examples of the nitrogen-containing compound having an acid dissociable group include N- (t-butoxycarbonyl) piperidine, N- (t-butoxycarbonyl) imidazole, N- (t-butoxycarbonyl) benzimidazole, N- (t -Butoxycarbonyl) 2-phenylbenzimidazole, N- (t-butoxycarbonyl) dioctylamine, N- (t-butoxycarbonyl) diethanolamine, N- (t-butoxycarbonyl) dicyclohexylamine, N- (t-butoxycarbonyl) diphenylamine Etc.

  The amount of the acid diffusion inhibitor is usually 15 parts by mass or less, preferably 0.001 to 10 parts by mass, with respect to 100 parts by mass of the acid dissociable group-modified alkali-soluble resin. It is still more preferable to set it as -5 mass parts. The amount of the acid diffusion inhibitor is preferably 15 parts by mass or less because the sensitivity as a resist and the developability of an exposed part can be improved. Moreover, when the compounding quantity of the said acid diffusion inhibitor shall be 0.001 mass part or more, since it can suppress that the pattern shape and dimensional fidelity as a resist fall with process conditions, it is preferable.

[2-D] Dissolution control agent (component D):
In addition to the above essential components, a dissolution control agent may be added to the positive radiation sensitive resin composition of the present invention. The dissolution control agent is an additive that has the effect of adjusting the solubility of the resin during alkali development. By adding a dissolution control agent, the dissolution contrast and dissolution rate of the resist are more appropriately controlled. It is possible to obtain a preferable effect. Examples of the dissolution control agent include t-butyl deoxycholate.

  The amount of the dissolution control agent is usually 0 to 20 parts by mass, preferably 0 to 10 parts by mass, and preferably 0 to 5 parts by mass with respect to 100 parts by mass of the acid dissociable group-modified alkali-soluble resin. More preferably. If the blending amount exceeds 20 parts by mass, the resolution tends to decrease, which is not preferable. On the other hand, it is preferable to add an acid diffusion inhibitor in the range of 0 to 5 parts by mass because an effect of improving LER (Line Edge Roughness) can be obtained.

[2-E] Solvent (E component):
In addition to the above essential components, a solvent may be blended in the positive radiation sensitive resin composition of the present invention. Examples of the solvent include ethers, esters, ether esters, ketones, ketone esters, amides, amide esters, lactams, lactones, (halogenated) hydrocarbons, and the like. . Specifically, ethylene glycol monoalkyl ethers, diethylene glycol dialkyl ethers, propylene glycol monoalkyl ethers, propylene glycol dialkyl ethers, ethylene glycol monoalkyl ether acetates, propylene glycol monoalkyl ether acetates, acetate esters, Hydroxyacetic acid esters, lactic acid esters, alkoxyacetic acid esters, (non) cyclic ketones, acetoacetic acid esters, pyruvate esters, propionate esters, N, N-dialkylformamides, N, N-dialkyl Examples include acetamides, N-alkylpyrrolidones, γ-lactones, (halogenated) aliphatic hydrocarbons, (halogenated) aromatic hydrocarbons, and the like.

  More specifically, for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol di-n-propyl ether. Diethylene glycol di-n-butyl ether,

  Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono-n-propyl ether acetate, isopropenyl acetate, isopropenyl propionate,

  Toluene, xylene, methyl ethyl ketone, cyclohexanone, 2-heptanone, 3-heptanone, 4-heptanone, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, ethyl ethoxyacetate, ethyl hydroxyacetate, 2-hydroxy- Methyl 3-methylbutyrate, methyl lactate, ethyl lactate, n-propyl lactate, i-propyl lactate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutylpropionate, 3-methyl-3-methoxybutyl butyrate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl acetoacetate, ethyl acetoacetate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropion Methyl acid, 3 Ethyl ethoxypropionate, N- methylpyrrolidone, N, N- dimethylformamide, N, N- dimethylacetamide and the like.

  Among these, when a propylene glycol monoalkyl ether acetate, 2-heptanone, lactic acid ester, 2-hydroxypropionic acid ester, 3-alkoxypropionic acid ester, or the like is used, in-film uniformity during coating is improved. Therefore, it is preferable. In preparing the radiation sensitive resin composition, the solvent may be used alone or in combination of two or more.

  In addition, the solvent may include other solvents (hereinafter referred to as “other solvents”) as necessary. Examples of the other solvent include benzyl ethyl ether, di-n-hexyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, acetonyl acetone, isophorone, caproic acid, caprylic acid, 1-octanol, 1-nonanol, and benzyl. Examples thereof include high-boiling solvents such as alcohol, benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate, γ-butyrolactone, ethylene carbonate, propylene carbonate, and ethylene glycol monophenyl ether acetate. One of these other solvents may be used alone, or two or more thereof may be mixed and used.

  The amount of the solvent used is usually 5 to 50% by mass, preferably 10 to 50% by mass, more preferably 10 to 40% by mass, and still more preferably 10 to 30% by mass in the total solid content in the homogeneous solution. The amount is particularly preferably 10 to 25% by mass. By setting it as this range, since the uniformity in a film surface at the time of application | coating becomes favorable, it is preferable. Moreover, when the said solvent contains the said other solvent, the usage-amount of the said other solvent is 50 mass% or less normally with respect to all the solvents, and it is preferable to set it as 30 mass% or less, 25 mass% More preferably, it is as follows.

[2-F] Other components:
The positive-type radiation-sensitive resin composition of the present invention may contain additives other than the above-described components, for example, a surfactant.

  As the surfactant, any of an anionic, cationic, nonionic or amphoteric surfactant can be used, but a nonionic surfactant is preferably used. Nonionic surfactants include, for example, polyoxyethylene higher alkyl ethers, polyoxyethylene higher alkyl phenyl ethers, polyethylene glycol higher fatty acid diesters, etc., and all of the following trade names: “KP” (Shin-Etsu) "Chemical Industry Co., Ltd.", "Polyflow" (manufactured by Kyoeisha Yushi Chemical Co., Ltd.), "F Top" (manufactured by Tochem Products), "Megafuck" (manufactured by Dainippon Ink and Chemicals), "Fluorard" (Sumitomo 3M) Etc.), “Asahi Guard” and “Surflon” (Asahi Glass Co., Ltd.). One of these surfactants may be used alone, or two or more thereof may be mixed and used.

  The said surfactant which can be added to the radiation sensitive resin composition of this invention shows the effect | action which improves the applicability | paintability, striation, developability, etc. of a radiation sensitive resin composition. When the surfactant is blended, the blending amount is usually 2 parts by mass or less, preferably 1. as an active ingredient of the surfactant with respect to 100 parts by mass of the total resin components in the radiation-sensitive resin composition. 5 parts by mass or less, more preferably 1 part by mass or less.

[2-G] Preparation of radiation-sensitive resin composition:
The radiation-sensitive resin composition of the present invention is usually prepared by dissolving each component in a solvent at the time of use to make a uniform solution, and then filtering by, for example, a filter having a pore size of about 0.2 μm as necessary. Is done.

[2-H] Formation of resist pattern:
When forming a resist pattern from the radiation-sensitive resin composition of the present invention, the radiation-sensitive resin composition solution prepared by the above method or the like is prepared by means such as spin coating, cast coating, roll coating, etc. A resist film is formed by coating on a substrate such as a silicon wafer or a wafer coated with aluminum. In some cases, a heat treatment (hereinafter referred to as “PB”) is performed in advance, and then the resist film is exposed through a predetermined mask pattern.

  The radiation that can be used for exposure includes the emission line spectrum of a mercury lamp (wavelength 254 nm), KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), etc., depending on the type of acid generator used. Far-ultraviolet rays, X-rays such as synchrotron radiation, and charged particle beams such as electron beams. Among these, far ultraviolet rays and charged particle beams are preferable, and KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm) and electron beam are particularly preferable. In addition, exposure conditions such as radiation dose are appropriately selected according to the composition of the radiation-sensitive resin composition of the present invention, the type of additive, and the like.

  Further, when a resist pattern is formed from the radiation-sensitive resin composition of the present invention, the apparent sensitivity of the resist can be improved by performing a heat treatment after exposure (hereinafter, this heat treatment is referred to as “PEB”). It is preferable because it is possible. The heating conditions for the PEB vary depending on the composition of the radiation-sensitive resin composition of the present invention, the type of additive, etc., but are usually 30 to 200 ° C., preferably 50 to 150 ° C.

  Then, a predetermined resist pattern is formed by developing the exposed resist film with an alkaline developer. Examples of the alkali developer include alkali metal hydroxides, aqueous ammonia, alkylamines, alkanolamines, heterocyclic amines, tetraalkylammonium hydroxides, choline, 1,8-diazabicyclo [5.4. 0.0] -7-undecene, 1,5-diazabicyclo [4.3.0] -5-nonene, and other alkaline compounds in which one or more alkaline compounds are dissolved are used. A particularly preferred alkaline developer is an aqueous solution of tetraalkylammonium hydroxides. Moreover, the density | concentration of the said alkaline aqueous solution is 10 mass% or less normally, Preferably it is 1-10 mass%, More preferably, it is 2-5 mass%. The concentration of the alkaline aqueous solution is preferably 10% by mass or less because it is possible to suppress the dissolution of the non-exposed portion in the developer.

  An appropriate amount of a surfactant or the like can be added to the developer composed of the alkaline aqueous solution. This is preferable because the wettability of the developer with respect to the resist can be improved. In addition, after developing with the developing solution which consists of the said alkaline aqueous solution, generally it wash | cleans with water and dries.

  Hereinafter, the onium salt, the radiation sensitive acid generator, and the positive radiation sensitive resin composition of the present invention will be described more specifically with reference to examples. However, these examples merely show some embodiments of the present invention. That is, the present invention should not be interpreted as being limited to these examples.

[Reference Examples 1 to 9]:
An acid dissociable group-modified alkali-soluble resin (component A), which is an essential component of the positive radiation sensitive resin composition of the present invention, was synthesized by the following method. For the synthesized resin, GPC columns (trade names: G2000HXL (× 2), G3000HXL (× 1), G4000HXL (× 1)) were used, flow rate: 1.0 ml / min, elution solvent: tetrahydrofuran, column Temperature: Polystyrene-converted weight average molecular weight (Mw) and polystyrene-converted number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard under analysis conditions of 40 ° C.

[Reference Example 1]:
101 g of p-acetoxystyrene, 5 g of styrene, 42 g of pt-butoxystyrene, 6 g of AIBN and 1 g of t-dodecyl mercaptan were dissolved in 160 g of propylene glycol monomethyl ether, and the reaction temperature was maintained at 70 ° C. under a nitrogen atmosphere. Polymerized for hours. After polymerization, the reaction solution was dropped into a large amount of hexane, and the resulting resin was coagulated and purified.

  Next, 150 g of propylene glycol monomethyl ether was added to the purified resin again, and then 300 g of methanol, 80 g of triethylamine and 15 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. After the reaction, the solvent and triethylamine were distilled off under reduced pressure. The obtained resin was dissolved in acetone, then dripped into a large amount of water to solidify the resin, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. By drying overnight, an acid-dissociable group-modified alkali-soluble resin was obtained.

The obtained resin had Mw of 16000 and Mw / Mn of 1.7. As a result of analysis using ¹³ C-NMR, the molar ratio of p-hydroxystyrene: styrene: pt-butoxystyrene in the copolymer was 72: 5: 23. This resin is referred to as “A-1 component”.

[Reference Example 2]:
100 g of p-acetoxystyrene, 25 g of t-butyl acrylate, 18 g of styrene, 6 g of AIBN and 1 g of t-dodecyl mercaptan were dissolved in 230 g of propylene glycol monomethyl ether, and then the reaction temperature was maintained at 70 ° C. for 16 hours under a nitrogen atmosphere. Polymerized. Thereafter, in the same manner as in Reference Example 1, an acid-dissociable group-modified alkali-soluble resin was obtained.

The obtained resin had Mw of 11500 and Mw / Mn of 1.6. As a result of analysis using ¹³ C-NMR, the molar ratio of p-hydroxystyrene: t-butyl acrylate: styrene in the copolymer was 61:19:20. This resin is referred to as “A-2 component”.

[Reference Example 3]:
After 97 g of p-acetoxystyrene, 51 g of pt-butoxystyrene, 6 g of AIBN and 1 g of t-dodecyl mercaptan were dissolved in 160 g of propylene glycol monomethyl ether, polymerization was carried out for 16 hours while maintaining the reaction temperature at 70 ° C. in a nitrogen atmosphere. It was. Thereafter, in the same manner as in Reference Example 1, an acid-dissociable group-modified alkali-soluble resin was obtained.

The obtained resin had Mw of 16,500 and Mw / Mn of 1.7. As a result of analysis using ¹³ C-NMR, the molar ratio of p-hydroxystyrene: pt-butoxystyrene in the copolymer was 67:33. This resin is referred to as “A-3 component”.

[Reference Example 4]:
25 g of poly (p-hydroxystyrene) was dissolved in 80 g of n-butyl acetate and bubbled with nitrogen gas for 30 minutes. Next, 49 g of di-t-butyl dicarbonate was added to this solution, and 25 g of triethylamine was further added, and the mixture was reacted at 60 ° C. for 7 hours. Thereafter, n-butyl acetate was distilled off under reduced pressure, the obtained resin was dissolved in acetone, then dripped into a large amount of water to solidify the resin, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. By drying overnight, an acid-dissociable group-modified alkali-soluble resin was obtained.

The obtained resin had Mw of 12000 and Mw / Mn of 1.7. Moreover, as a result of analysis using ¹³ C-NMR, it was found that 26 mol% of the hydrogen atoms constituting the phenolic hydroxyl group in poly (p-hydroxystyrene) was substituted with a t-butoxycarbonyl group. It was. This resin is referred to as “A-4 component”.

[Reference Example 5]:
25 g of poly (p-hydroxystyrene) was dissolved in 100 g of propylene glycol monomethyl acetate and bubbled with nitrogen gas for 30 minutes. Next, 4.8 g of ethyl vinyl ether was added to this solution, 1 g of p-toluenesulfonic acid pyridinium salt was added as a catalyst, and the mixture was allowed to react at room temperature for 12 hours. Thereafter, the reaction solution is dropped into a 1% by mass aqueous ammonia solution to precipitate the resin, and the produced white powder is filtered and dried overnight at 50 ° C. under reduced pressure to obtain an acid-dissociable group-modified alkali-soluble resin. It was.

The obtained resin had Mw of 13000 and Mw / Mn of 1.7. Further, as a result of analysis using ¹ H-NMR, it was found that 34 mol% of the hydrogen atoms constituting the phenolic hydroxyl group in poly (p-hydroxystyrene) was substituted with an ethoxyxyethyl group. . This resin is referred to as “A-5 component”.

[Reference Example 6]:
25 g of a copolymer having a molar ratio of p-hydroxystyrene: pt-butoxycarbonyloxystyrene of 92: 8 in the copolymer was dissolved in 100 g of propylene glycol monomethyl acetate and bubbled with nitrogen gas for 30 minutes. . Next, 3.3 g of ethyl vinyl ether was added to this solution, 1 g of p-toluenesulfonic acid pyridinium salt was added as a catalyst, and the mixture was allowed to react at room temperature for 12 hours. Thereafter, the reaction solution is dropped into an aqueous ammonia solution having a concentration of 1% by mass to precipitate the resin, and the produced white powder is filtered and dried overnight at 50 ° C. under reduced pressure to thereby acid-dissociable group-modified alkali-soluble resin. Got.

The obtained resin had Mw of 13000 and Mw / Mn of 1.8. Further, as a result of analysis using ¹³ C-NMR, it was found that 23 mol% of the hydrogen atoms constituting the phenolic hydroxyl group in poly (p-hydroxystyrene) were ethoxyxyethyl groups and 8 mol% were t-butyl groups. It had a substituted structure. This resin is referred to as “A-6 component”.

[Reference Example 7]:
25 g of a copolymer having a molar ratio of p-hydroxystyrene: pt-butoxystyrene in the copolymer of 90:10 was dissolved in 100 g of propylene glycol monomethyl acetate, and bubbled with nitrogen gas for 30 minutes. Thereafter, in the same manner as in Reference Example 6, an acid-dissociable group-modified alkali-soluble resin was obtained.

The obtained resin had Mw of 13000 and Mw / Mn of 1.01. Moreover, as a result of analysis using ¹³ C-NMR, 23 mol% of the hydrogen atoms constituting the phenolic hydroxyl group in poly (p-hydroxystyrene) are ethoxyxyethyl groups and 10 mol% are t-butyl groups. It had a substituted structure. This resin is referred to as “A-7 component”.

[Reference Example 8]:
Uniformly 5 g of norbornene, 11 g of maleic anhydride, 11 g of 8-hydroxytetracyclo [4.4.0.12,5.17,10] dodec-3-ene and 23 g of 2-methyl-2-adamantyl methacrylate are uniformly added to 50 g of tetrahydrofuran. And was bubbled with nitrogen gas for 30 minutes. Next, 3 g of azobisisobutyronitrile as a polymerization initiator was added to this solution and heated to 65 ° C. Thereafter, the mixture was heated and stirred for 6 hours while maintaining the same temperature. After completion of the reaction, the reaction solution was cooled to room temperature, diluted with 50 g of tetrahydrofuran, poured into 1000 ml of n-hexane, and the precipitated white powder was separated by filtration and dried to obtain a resin.

  The resulting resin had an Mw of 6100, norbornene: maleic anhydride in the copolymer: 8-hydroxytetracyclo [4.4.0.12,5.17,10] dodec-3-ene: methacrylic acid 2 It was a copolymer having a molar ratio of -methyl-2-adamantyl of 15: 35: 20: 30. This resin is referred to as “A-8 component”.

[Reference Example 9]:
30 g of the compound represented by the following general formula (9) and 20 g of 2-methyl-2-adamantyl methacrylate were dissolved in 50 g of tetrahydrofuran to obtain a uniform solution, and then bubbled with nitrogen gas for 30 minutes. Thereafter, in the same manner as in Reference Example 8, an acid-dissociable group-modified alkali-soluble resin was obtained.

  The obtained resin was a copolymer having a Mw of 12000 and a molar ratio of the compound of the formula (9): 2-methyl-2-adamantyl methacrylate in the copolymer of 60:40. This resin is designated as “A-9 component”.

[Example 1]:
An onium salt represented by the following general formula (10), 4- (2-cyanoethoxy) phenyldiphenylsulfonium perfluoro-n-butanesulfonate, was synthesized by the following method.

  In the reaction flask, 30 g of 4-hydroxyphenyldiphenylsulfonium perfluoro-n-butanesulfonate was dissolved in 300 g of dichloromethane, and nitrogen substitution was performed to perform nitrogen substitution. Then, 17.9 g of 3-chloropropionitrile was added, followed by 10.5 g of triethylamine, and the mixture was stirred at room temperature for 1 hour.

  Next, 100 g of ion-exchanged water was added, the mixed solution was transferred to a separatory funnel, shaken, and allowed to stand, and then the aqueous layer was removed. Further, 300 ml of distilled water was added and shaken, allowed to stand, and then the aqueous layer was removed. The remaining dichloromethane solution was dried over anhydrous magnesium sulfate and filtered. Then, dichloromethane was distilled off from the dichloromethane solution after drying using an evaporator, and the obtained liquid was dried under reduced pressure to give 4- (2-cyanoethoxy) phenyldiphenylsulfonium perfluoro-n-butanesulfonate 26. 7 g was obtained. This compound is referred to as “component B-1”.

As a result of analyzing this compound using ¹ H-NMR (trade name: JNM-EX270, manufactured by JEOL Ltd.) and using a deuterated chloroform as a measurement solvent, the resulting chemical shift was determined by ¹ H-NMR [ σ ppm (CD ₃ Cl): 3.78 (2H, t, J = 6.9 Hz, CH ₂ ), 4.34 (2H, t, J = 6.9 Hz, CH ₂ ), 7.16-7.78 (14H, m, Ar)] and confirmed to be the target compound.

  In addition, as a result of analysis using a mass spectrometer (trade name: JMS-AX505W, manufactured by JEOL Ltd.) under the conditions described in Table 2, 332 parent ion peaks were detected and confirmed to be the target compound. .

[Examples 2-9, Comparative Examples 1-2]:
A positive radiation sensitive resin composition was prepared using the onium salt of Example 1 as a radiation sensitive acid generator. Specifically, the acid-dissociable group-modified alkali-soluble resin shown in Table 3 (referred to as “resin” and “component A” in the table), the radiation-sensitive acid generator of the present invention (referred to as “acid generator” in the table) ”,“ B component ”), other radiation sensitive acid generator (in the table,“ acid generator ”,“ B ′ component ”), acid diffusion inhibitor (in the table,“ inhibitor ”, Mixing each component of “C component”), dissolution control agent (in the table, “control agent”, “D component”) and solvent (in the table, “E component”) to obtain a uniform solution Then, the radiation sensitive resin composition solutions of Examples 2 to 9 and Comparative Examples 1 and 2 were prepared by filtering using a membrane filter having a pore size of 0.2 μm. Details of the B ′ component, C component, D component, and E component used in Examples and Comparative Examples are shown in Table 4.

[Evaluation methods]:
About the radiation sensitive resin composition of an Example and a comparative example, the evaluation was performed by performing the following tests.

  After spin-coating the radiation sensitive resin composition solutions of Examples 2 to 9 and Comparative Examples 1 and 2 onto a silicon wafer, PB is performed under the conditions shown in Table 2 to obtain resist films having the film thicknesses shown in Table 2. Formed. Subsequently, after exposing on the conditions shown in Table 2, PEB was performed on the conditions shown in Table 2. Then, using a tetramethylammonium hydroxide aqueous solution (concentration 2.38% by mass), development was performed by a paddle method at 23 ° C. for 1 minute, and then washed with pure water and dried to form a resist pattern.

  As an exposure apparatus, KrF excimer laser (trade name: Stepper NSR2205 EX12B, Nikon Corporation, numerical aperture 0.55) or ArF excimer laser (trade name: ArF excimer laser exposure equipment, Nikon Corporation, numerical aperture 0.55) It was used. In the table, KrF excimer laser is abbreviated as “KrF”, and ArF excimer laser is abbreviated as “ArF”.

  About the resist pattern prepared by the said method, performance evaluation was performed by the method shown below. The results are shown in Table 2.

(1) Sensitivity: When a resist film formed on a silicon wafer is exposed at a different exposure amount, immediately post-exposure baking is performed, then alkali development is performed, followed by washing with water and drying to form a resist pattern. The exposure amount for forming a line-and-space pattern (1L1S) having a width of 0.250 μm in a one-to-one line width was taken as the optimum exposure amount, and this optimum exposure amount was taken as the sensitivity.

(2) Resolution (μm): The minimum dimension (μm) of the resist pattern resolved when exposed at the optimum exposure amount was determined as the resolution.

(3) Pattern shape: The dimension La of the lower side and the dimension Lb of the upper side of the rectangular cross section of the line and space pattern (1L1S) with a line width of 0.25 μm formed on the silicon wafer were measured using a scanning electron microscope. Measured and evaluated according to the following criteria.
A: satisfying the condition of 0.85 ≦ Lb / La ≦ 1 (good),
X: Not satisfying the condition of 0.85 ≦ Lb / La ≦ 1 (defect).

(4) Storage stability: The radiation-sensitive resin composition was prepared by the above method, the test sample whose sensitivity was calculated was allowed to stand at room temperature for 1 month, the sensitivity was calculated again, and evaluated according to the following criteria.
○: Sensitivity not changed by 10% or more compared with the initially calculated sensitivity (good),
X: Sensitivity changed by 10% or more compared with the initially calculated sensitivity (defect).

[Evaluation results]:
As is apparent from the data in Table 3, the positive type radiation-sensitive resin compositions of the examples using the onium salt of the present invention as an acid generator were compared without using the onium salt of the present invention as an acid generator. Compared with the examples, the resolution was remarkably improved, and extremely good results were shown. Also, the sensitivity value was small and the sensitivity was high. Furthermore, good results were also shown for the pattern shape and storage stability.

  The onium salt, the radiation sensitive acid generator and the radiation sensitive resin composition of the present invention can obtain a sufficiently satisfactory high resolution. For example, in addition to exhibiting excellent resolution capable of forming a high-definition resist pattern of less than 0.13 μm with a KrF excimer laser and less than 0.11 μm with an ArF excimer laser, it exhibits good storage stability. Therefore, it can be suitably used in the field of microfabrication, particularly in the manufacture of integrated circuit elements such as semiconductor devices in which miniaturization, high definition, and high integration are rapidly progressing.

Claims (4)

An onium salt represented by the following general formula (1).

[In General Formula (1), A is a sulfur atom, Ar ¹ is the same or different and each is an aromatic hydrocarbon group having 6 to 20 carbon atoms, Ar ² is the same or different, each having 6 to 20 carbon atoms aromatic hydrocarbon group, B represents a structure represented by the following general formula (i), Y ^- represents a sulfonate anion. m is an integer of 1 to 3, n is an integer of 0 to 2 (where m + n = 3), and x is an integer of 1 to 2. ]
Z-B '(i)
[In General Formula (i), Z represents an oxygen atom , and B ′ represents a methylene group or an alkylene group. ]   A radiation-sensitive acid generator containing at least one onium salt according to claim 1. An acid-dissociable group-modified alkali-soluble resin (component A) having an acidic group and at least part of the acidic group protected by an acid-dissociable group and a radiation-sensitive acid generator (component B) are essential. A positive-type radiation-sensitive resin composition contained as a component,
A positive radiation sensitive resin composition containing at least one onium salt according to claim 1 as the B component.   Furthermore, the positive radiation sensitive resin composition of Claim 3 which contains an acid diffusion inhibitor (C component) as a structural component.