WO2013008700A1

WO2013008700A1 - Actinic ray-sensitive or radiation-sensitive resin composition, resist film and pattern forming method each using the composition, manufacturing method of electronic device and electronic device

Info

Publication number: WO2013008700A1
Application number: PCT/JP2012/067140
Authority: WO
Inventors: Akinori Shibuya; Tomoki Matsuda; Katsuhiro Shimono; Yoko Tokugawa
Original assignee: Fujifilm Corporation
Priority date: 2011-07-11
Filing date: 2012-06-28
Publication date: 2013-01-17
Also published as: JP2013020089A; TW201307997A

Abstract

An actinic ray-sensitive or radiation-sensitive resin composition, includes: (A) a compound represented by the following formula (I); and (B) a resin: wherein X represents an oxygen atom, a sulfur atom or -N(Rx)-; each of R₁ to R₈ and Rx independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, an alkylcarbonyloxy group, an aryl group, an aryloxy group, an aryloxycarbonyl group or an arylcarbonyloxy group; and R₁ to R₈ may combine with each other to form a ring, provided that at least two members out of R₁ to R₈represent a structure represented by the following formula (II) as defined in the specification.

Description

DESCRIPTION

Title of Invention

ACTINIC RAY-SENSITIVE OR RADIATION-SENSITIVE RESIN COMPOSITION, RESIST FILM AND PATTERN FORMING METHOD EACH USING THE COMPOSITION, MANUFACTURING METHOD OF ELECTRONIC DEVICE AND ELECTRONIC DEVICE

Technical Field

The present invention relates to an actinic ray-sensitive or radiation-sensitive resin composition capable of undergoing a reaction upon irradiation with an actinic ray or radiation■ > to change in the property, and a resist film and a pattern forming method each using the composition. More specifically, the present invention relates to an actinic ray-sensitive or radiation-sensitive resin composition for use in the production process of a semiconductor such as IC, in the production of a liquid crystal device or a circuit board such as thermal heads, in other photofabrication processes, or in a lithographic printing plate or an acid-curable composition, a resist film and a pattern forming method each using the composition, a manufacturing method of an electronic device and an electronic device.

Background Art

A chemical amplification resist composition is a pattern forming material which forms a pattern on a substrate by producing an acid in the exposed area upon irradiation with radiation such as far ultraviolet light and through a reaction using the acid as a catalyst, changing the developer solubility of the area irradiated with an actinic radiation and that of the non-irradiated area.

In the case of using a KrF excimer laser as the exposure light source, a resin having small absorption in the wavelength region of 248 nm and having a basic backbone of poly(hydroxystyrene) is predominantly used as the main component and therefore, this is an excellent system capable of forming a good pattern with high sensitivity and high resolution, compared with the conventional naphthoquinone-diazide/novolak resin system.

On the other hand, in the case where a light source of emitting light at a shorter wavelength, for example, an ArF excimer laser (193 nm), is used as the exposure light source, a satisfactory pattern cannot be formed even by the above-described chemical amplification system, because the compound having an aromatic group substantially has large absorption in the region of 193 nm. In order to solve this problem, various resist compositions for use with an ArF excimer laser, containing a resin having an alicyclic hydrocarbon structure, have been developed.

Also, with respect to the photoacid generator that is a main constituent component of the chemical amplification resist composition, various compounds have been developed. For example, JP-A-2005-308969 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") describes a photoacid generator composed of a sulfonium salt having an indole group or the like, JP-A-2010-235579 describes a photoacid generator composed of an aromatic sulfonium salt compound having a carbazole structure, and JP-A-2006-99024 describes a compound for a resist composition, containing a plurality of sulfonium structures.

However, in view of the overall performance as a resist, it is actually very difficult to find out an appropriate combination of a resin, a photoacid generator, a basic compound, an additive, a solvent and the like used, and existing techniques are still insufficient. For example, development of a resist composition ensuring excellent exposure sensitivity and little development defect is demanded.

Summary of Invention

Considering these background arts, an object of the present invention is to provide an actinic ray-sensitive or radiation-sensitive resin composition ensuring excellent high exposure sensitivity and little development defect, a resist film and a pattern forming method each using the composition, a manufacturing method of an electronic device and an electronic device.

[1] An actinic ray-sensitive or radiation-sensitive resin composition, comprising:

(A) a compound represented by the following formula (I); and

(B) a resin:

wherein X represents an oxygen atom, a sulfur atom or -N(Rx)-;

each of

to R₈ and Rx independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, an alkylcarbonyloxy group, an aryl group, an aryloxy group, an aryloxycarbonyl group or an arylcarbonyloxy group; and

Ri to R₈ may combine with each other to form a ring,

provided that at least two members out of

to R₈ represent a structure represented by the following formula (II):

wherein each of R9 and R₁₀ independently represents an alkyl group, a cycloalkyl group or an aryl group when X is an oxygen atom or a sulfur atom, and independently represents an alkyl group or a cycloalkyl group when X is -N(Rx)-, and each R9 and each R]₀ may be the same as or different from every other R₉ and every other R₁₀, respectively;

R9 and Rio may combine with each other to form a ring; and

Z^" represents a non-nucleophilic anion, each Z^" may be the same as or different from every other Z^~, and a plurality of Z^"'s may combine to form a polyvalent non-nucleophilic anion.

[2] The actinic ray-sensitive or radiation-sensitive resin composition as described in [1] above,

wherein Z^" in formula (II) is a sulfonate anion.

[3] The actinic ray-sensitive or radiation-sensitive resin composition as described in [2] above,

wherein Z^" in formula (II) is an anion represented by the following formula (III):

wherein each Xf independently represents a fluorine atom or an alkyl group substituted with at least one fluorine atom;

each of Ru and Ri₂ independently represents a hydrogen atom, a fluorine atom, an alkyl group or an alkyl group substituted with at least one fluorine atom, and when a plurality of Ri i's and a plurality of Ri₂'s are present, each Ru and each R_]2 may be the same as or different from every other Ru and every other Ri₂, respectively;

L represents a divalent linking group, and when a plurality of L's are present, each L may be the same as or different from every other L; A represents a cyclic organic group; and

x represents an integer of 1 to 20, y represents an integer of 0 to 10 and z represents an integer of 0 to 10.

[4] The actinic ray-sensitive or radiation-sensitive resin composition as described in any one of [ 1] to [3] above,

wherein each of R9 and Rio in formula (II) is independently an alkyl group or a cycloalkyl group, and R9 and Rio may combine with each other to form a ring.

[5] The actinic ray-sensitive or radiation-sensitive resin composition as described in any one of [1] to [4] above,

wherein R9 and Rio in formula (II) are combined to form a ring.

[6] The actinic ray-sensitive or radiation-sensitive resin composition as described in any one of [ 1] to [5] above,

wherein X represents -N(Rx)-, Rx in formula (I) is an alkyl group, a cycloalkyl group or an aryl group each having a structure represented by formula (II) as a substituent, and at least one member out of Ri to Rg is a structure represented by formula (II).

[7] The actinic ray-sensitive or radiation-sensitive resin composition as described in any one of [1] to [6] above,

wherein the resin (B) is a resin capable of decomposing by an action of an acid to increase a solubility of the resin (B) in an alkali developer.

[8] A resist film, which is formed by using the actinic ray-sensitive or radiation-sensitive resin composition as described in any one of [1 ] to [7] above.

[9] A pattern forming method, comprising:

a step of exposing the resist film as described in [8] above, so as to form an exposed resist film; and

a step of developing the exposed resist film.

[10] The pattern forming method as described in [9] above,

wherein the exposure is immersion exposure.

[11 ] A manufacturing method of an electronic device, comprising:

the pattern forming method as described in [9] or [10] above.

[12] An electronic device, which is manufactured by the manufacturing method of an electronic device as described in [ 11] above.

The present invention preferably further includes the following configurations.

[ 13] The actinic ray-sensitive or radiation-sensitive resin composition as described in any one of [1] to [7] above,

wherein the resin (B) contains a repeating unit having a lactone structure or a sultone structure.

[14] The actinic ray-sensitive or radiation-sensitive resin composition as described in any one of [1] to [7] and [13] above, further comprising:

(HR) a hydrophobic resin.

[15] The actinic ray-sensitive or radiation-sensitive resin composition as described in [14] above,

wherein the hydrophobic resin (HR) is a hydrophobic resin having at least either a fluorine atom or a silicon atom.

[16] The pattern forming method as described in [9] or [10] above,

wherein the exposure is exposure to an ArF excimer laser.

Description of Embodiments

In the present specification, when a group (atomic group) is denoted without specifying whether substituted or unsubstituted, the group includes both a group having no substituent and a group having a substituent. For example, "an alkyl group" includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

In the present specification, the term "actinic ray" or "radiation" indicates, for example, a bright line spectrum of mercury lamp, a far ultraviolet ray typified by excimer laser, an extreme-ultraviolet ray (EUV light), an X-ray or an electron beam (EB). Also, in the present specification, the "light" means an actinic ray or radiation.

In the present specification, unless otherwise indicated, the "exposure" includes not only exposure to a mercury lamp, a far ultraviolet ray typified by excimer laser, an X-ray, EUV light or the like but also lithography with a particle beam such as electron beam and ion beam.

The actinic ray-sensitive or radiation-sensitive resin composition of the present invention includes:

(A) a compound represented by the following formula (I) capable of generating an acid upon irradiation with an actinic ray or radiation (hereinafter, sometimes referred to as "compound (A)" or "photoacid generator (A)"), and

(B) a resin:

wherein in formula (I), X represents an oxygen atom, a sulfur atom or -N(Rx)-;

each of R_\ to R₈ and Rx independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, an alkylcarbonyloxy group, an aryl group, an aryloxy group, an aryloxycarbonyl group or an arylcarbonyloxy group; and

Ri to Rg may combine with each other to form a ring,

provided that at least two members out of Ri to R₈ represent a structure represented by the following formula (II):

wherein in formula (II), each of R9 and Rio independently represents an alkyl group, a cycloalkyl group or an aryl group when X is an oxygen atom or a sulfur atom, and independently represents an alkyl group or a cycloalkyl group when X is -N(Rx)-, and each R and each Ri₀ may be the same as or different from every other R9 and every other Rio, respectively;

R9 and Rio may combine with each other to form a ring; and

Z^" represents a non-nucleophilic anion, each Z^" may be the same as or different from every other Z^", and a plurality of Z^"'s may combine to form a polyvalent non-nucleophilic anion.

By virtue of containing the compound (A), the actinic ray-sensitive or radiation-sensitive resin composition of the present invention can ensure excellent high exposure sensitivity and little development defect. The reason therefor is not clearly known, but it is presumed that cleavage of the C-S⁺ bond after light absorption and excitation occurs with high efficiency, which contributes to enhancement of the sensitivity, and thanks to a polyvalent ionic compound, the compound exhibits excellent solubility in an alkali developer and is less likely to become a scum after development, which contributes to reduction in the development defect.

The actinic ray-sensitive or radiation-sensitive resin composition of the present invention is, for example, a positive composition and is typically a positive resist composition.

Respective components of this composition are described below.

[ 1 ] (A) Compound represented by formula (I)

As described above, the actinic ray-sensitive or radiation-sensitive resin composition of the present invention contains (A) a compound represented by formula (I). The compound (A) represented by formula (I) is a compound capable of generating an acid upon irradiation with an actinic ray or radiation.

The compound (A) represented by formula (I) capable of generating an acid upon irradiation with an actinic ray or radiation is described in detail below.

The alkyl group as Ri to R₁₀ and Rx may have a substituent and is preferably a linear or branched alkyl group having a carbon number of 1 to 20, and the alkyl chain may contain an oxygen atom, a sulfur atom or a nitrogen atom. The alkyl group specifically includes a linear alkyl group such as methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-dodecyl group, n-tetradecyl group and n-octadecyl group, and a branched alkyl group such as isopropyl group, isobutyl group, tert-butyl group, neopentyl group and 2-ethylhexyl group.

Examples of the alkyl group having a substituent for Rx include a cyanomethyl group, a 2,2,2-trifluoroethyl group, a methoxycarbonylmethyl group, and an ethoxycarbonylmethyl group.

The alkyl group having a substituent for R and Rio include a methoxyethyl group.

Other examples include a group where a cycloalkyl group is substituted on a linear or branched alkyl group (for example, an adamantylmethyl group, an adamantyl group, a cyclohexylethyl group and a camphor residue group).

The cycloalkyl group as Ri to R]₀ and Rx may have a substituent and is preferably a cycloalkyl group having a carbon number of 3 to 20, and the cycloalkyl group may contain an oxygen atom in the ring. Specific examples of the cycloalkyl group include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group and an adamantyl group.

The alkoxy group as Ri to R₈ and Rx may have a substituent and is preferably an alkoxy group having a carbon number of 1 to 20. Specific examples thereof include a methoxy group, an ethoxy group, an isopropyloxy group and a cyclohexyloxy group.

The alkoxycarbonyl group as Ri to R₈ and Rx may have a substituent and is preferably an alkoxycarbonyl group having a carbon number of 2 to 20. Specific examples thereof include a methoxycarbonyl group, an ethoxycarbonyl group, an isopropoxycarbonyl group, and a cyclohexyloxycarbonyl group.

The acyl group as

to R₈ and Rx may have a substituent and is preferably an acyl group having a carbon number of 2 to 10. Specific examples thereof include an acetyl group, a propionyl group and an isobutyryl group.

The alkylcarbonyloxy group as Ri to Rg and Rx may have a substituent and is preferably an alkylcarbonyloxy group having a carbon number of 2 to 20. Specific examples thereof include a methylcarbonyloxy group, an ethylcarbonyloxy group, an isopropylcarbonyloxy group and a cyclohexylcarbonyloxy group.

The aryl group as Ri to Ri₀ and Rx may have a substituent and is preferably an aryl group having a carbon number of 6 to 14, and examples thereof include a phenyl group and a naphthyl group.

The aryloxy group as

to Rg and Rx may have a substituent and is preferably an aryloxy group having a carbon number of 6 to 14, and examples thereof include a phenyloxy group and a naphthyloxy group.

The aryloxycarbonyl group as Ri to R₈ and Rx may have a substituent and is preferably an aryloxycarbonyl group having a carbon number of 7 to 15, and examples thereof include a phenyloxycarbonyl group and a naphthyloxycarbonyl group.

The arylcarbonyloxy group as R) to R₈ and Rx may have a substituent and is preferably an arylcarbonyloxy group having a carbon number of 7 to 15, and examples thereof include a phenylcarbonyloxy group and a naphthyl carbonyloxy group.

Examples of the substituent which may be substituted on each of the cycloalkyl group as Ri to Rio and Rx, the alkoxy group as Ri to Rg and Rx, the alkoxycarbonyl group as R to Rg and Rx, the alkylcarbonyloxy group as R_\ to R₈ and Rx, the aryl group as R_\ to Rio and Rx, the aryloxy group as Ri to R₈ and Rx, the aryloxycarbonyl group as Ri to R₈ and Rx, and the arylcarbonyloxy group as Ri to R₈ and Rx include an alkyl group (may be linear, branched or cyclic, preferably having a carbon number of 1 to 12), an aryl group (preferably having a carbon number of 6 to 14), a nitro group, a halogen atom such as fluorine atom, a carboxyl group, a hydroxyl group, an amino group, a cyano group, an alkoxy group (preferably having a carbon number of 1 to 15), a cycloalkyl group (preferably having a carbon number of 3 to 15), and an acyl group (preferably having a carbon number of 2 to 12).

In particular, Rx may be an alkyl group, a cycloalkyl group or an aryl group each having a structure represented by formula (II) as a substituent.

In the present invention, at least two members out of Ri to R₈ represent a structure represented by formula (II), but in the case where Rx is an alkyl group, a cycloalkyl group or an aryl group each having a structure represented by formula (II) as a substituent, at least one of Ri to R₈ may be a structure represented by formula (II).

In the present invention, R9 and R_]0 are preferably combined to form a ring.

The ring structure which may be formed by combining R₉ and Ri₀ with each other is a

5- or 6-membered ring formed by divalent R₉ and Rio (for example, an ethylene group, a propylene group or a 1,2-cyclohexylene group and the like) together with the sulfur atom in formula (II), preferably a 5-membered ring (that is, a tetrahydrothiophene ring).

The ring structure which may be formed by combining any two or more members out of R] to R₈ with each other is preferably a 5- or 6-membered ring, more preferably a

6- membered ring.

Each of R9 and R_!0 independently represents an alkyl group, a cycloalkyl group or an aryl group when X is an oxygen atom or a sulfur atom, and independently represents an alkyl group or a cycloalkyl group when X is -N(Rx)-.

In every case where X in formula (I) is an oxygen atom, a sulfur atom or -N(Rx)-, it is preferred that each of R9 and R_]0 in formula (II) is independently an alkyl group or a cycloalkyl group and R9 and Rio may combine with each other to form a ring.

Particularly preferred examples of Ri to R₈ include an alkyl group which may have a substituent and a hydrogen atom, but in the case of use as an ArF resist, from the standpoint of absorption intensity at 193 nm, a hydrogen atom is more preferred.

Rx is preferably an alkyl group.

Z^" represents a non-nucleophilic anion (an anion having an extremely low ability of causing a nucleophilic reaction), each Z^" may be the same as or different from every other Z , and a plurality of Z^"'s may combine to form a polyvalent (for example, at least divalent) non-nucleophilic anion.

Examples of Z^" include a sulfonate anion (such as aliphatic sulfonate anion, aromatic sulfonate anion and camphorsulfonate anion), a carboxylate anion (such as aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion), a sulfonylimide anion, a bis(alkylsulfonyl)imide anion and a tris(alkylsulfonyl)methide anion.

The aliphatic moiety in the aliphatic sulfonate anion and aliphatic carboxylate anion may be an alkyl group or a cycloalkyl group and is preferably a linear or branched alkyl group having a carbon number of 1 to 30, or a cycloalkyl group having a carbon number of 3 to 30.

Examples of the case where a plurality of Z^"'s combine to form a polyvalent non-nucleophilic anion include an embodiment where two aliphatic sulfonate anions combine at the aliphatic group moiety to form an alkylene group or a cycloalkylene group.

The aromatic group in the aromatic sulfonate anion and aromatic carboxylate anion is preferably an aryl group having a carbon number of 6 to 14, and examples thereof include a phenyl group, a tolyl group and a naphthyl group.

The alkyl group, cycloalkyl group and aryl group described above may have a substituent. Specific examples of the substituent include a nitro group, a halogen atom such as fluorine atom, a carboxyl group, a hydroxyl group, an amino group, a cyano group, an alkoxy group (preferably having a carbon number of 1 to 15), a cycloalkyl group (preferably having a carbon number of 3 to 15), an aryl group (preferably having a carbon number of 6 to 14), an alkoxycarbonyl group (preferably having a carbon number of 2 to 7), an acyl group (preferably having a carbon number of 2 to 12), an alkoxycarbonyloxy group (preferably having a carbon number of 2 to 7), an alkylthio group (preferably having a carbon number of 1 to 15), an alkylsulfonyl group (preferably having a carbon number of 1 to 15), an alkyliminosulfonyl group (preferably having a carbon number of 2 to 15), an aryloxysulfonyl group (preferably having a carbon number of 6 to 20), an alkylaryloxysulfonyl group (preferably having a carbon number of 7 to 20), a cycloalkylaryloxysulfonyl group (preferably having a carbon number of 10 to 20), an alkyloxyalkyloxy group (preferably having a carbon number of 5 to 20), and a cycloalkylalkyloxyalkyloxy group (preferably having a carbon number of 8 to 20). The aryl group or ring structure in each group may further have an alkyl group (preferably having a carbon number of 1 to 15) as a substituent.

The aralkyl group in the aralkylcarboxylate anion is preferably an aralkyl group having a carbon number of 7 to 12, and examples thereof include a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group and a naphthylbutyl group.

Examples of the sulfonylimide anion include saccharin anion.

The alkyl group in the bis(alkylsulfonyl)imide anion and tris(alkylsulfonyl)methide anion is preferably an alkyl group having a carbon number of 1 to 5.

Two alkyl groups in the bis(alkylsulfonyl)imide anion may combine to form an alkylene group (preferably having a carbon number of 2 to 4) and may form a ring together with the imido group and two sulfonyl group. The ring structure which may be formed by the bis(alkylsulfonyl)imide anion is preferably a 5- to 7-membered ring, more preferably a 6-membered ring.

Examples of the substituent which may be substituted on the alkyl group and the alkylene group formed by combining two alkyl groups in the bis(alkylsulfonyl)imide anion include a halogen atom, a halogen atom-substituted alkyl group, an alkoxy group, an alkylthio group, an alkyloxysulfonyl group, an aryloxysulfonyl group and a cycloalkylaryloxysulfonyl group, with a fluorine and a fluorine atom-substituted alkyl group being preferred.

Other examples of Z^" include fluorinated phosphorus (e.g., PF₆ ^"), fluorinated boron (e.g., BF₄ ^") and fluorinated antimony (e.g., SbF₆ ^").

Z^" is preferably an aliphatic sulfonate anion substituted with a fluorine atom at least at the a-position of the sulfonic acid, an aromatic sulfonate anion substituted with a fluorine atom or a fluorine atom-containing group, a bis(alkylsulfonyl)imide anion in which the alkyl group is substituted with a fluorine atom, or a tris(alkylsulfonyl)methide anion in which the alkyl group is substituted with a fluorine atom. The non-nucleophilic anion is more preferably a perfluoroaliphatic sulfonate anion (more preferably having a carbon number of 4 to 8) or a benzenesulfonate anion having a fluorine atom, still more preferably nonafluorobutanesulfonate anion, perfluorooctanesulfonate anion, pentafluorobenzenesulfonate anion, or 3,5-bis(trifluoromethyl)benzenesulfonate anion.

In terms of the acid strength, pKa of the acid generated is preferably - 1 or less so as to enhance the sensitivity.

Particularly preferred Z^" includes the following anion structure.

In formula (III), each Xf independently represents a fluorine atom or an alkyl group substituted with at least one fluorine atom.

Each of Ri i and Ri₂ independently represents a hydrogen atom, a fluorine atom, an alkyl group or an alkyl group substituted with at least one fluorine atom, and when a plurality of Rn's and a plurality of R]₂'s are present, each Rn and each R_{] 2} may be the same as or different from every other Ru and every other R|₂, respectively.

L represents a divalent linking group, and when a plurality of L's are present, each L may be the same as or different from every other L.

A represents a cyclic organic group.

x represents an integer of 1 to 20, y represents an integer of 0 to 10, and z represents an integer of 0 to 10. The anion of formula (III) is described in detail below.

Xf is a fluorine atom or an alkyl group substituted with at least one fluorine atom, and the alkyl group in the fluorine atom-substituted alkyl group is preferably an alkyl group having a carbon number of 1 to 10, more preferably a carbon number of 1 to 4. Also, the fluorine atom-substituted alkyl group of Xf is preferably a perfluoroalkyl group.

Xf is preferably a fluorine atom or a perfluoroalkyl group having a carbon number of 1 to 4. Specific examples include a fluorine atom, CF₃, C₂F₅, C₃F₇, C₄F9, C₅Fn, C₆F[₃, C₇Fi₅, C₈Fi7, CH₂CF₃, CH₂CH₂CF₃, CH₂C₂F₅, CH₂CH₂C₂F₅, CH₂C₃F₇, CH₂CH₂C₃F₇, CH₂C₄F₉ and CH₂CH₂C₄F₉, with a fluorine atom and CF being preferred. In particular, it is preferred that both Xf are a fluorine atom.

Each of R1 1 and Ri₂ represents a hydrogen atom, a fluorine atom or an alkyl group, and the alkyl group may have a substituent (preferably fluorine atom) and is preferably an alkyl group having a carbon number of 1 to 4, more preferably a perfluoroalkyl group having a carbon number of 1 to 4. Specific examples of the alkyl group having a substituent of Ru and R₁₂ include CF₃, C₂F₅, C₃F₇, C₄F₉, C₅F„, C₆F₁₃, C₇F₁₅, C₈F₁₇, CH₂CF₃, CH₂CH₂CF₃, CH₂C₂F₅, CH₂CH₂C₂F₅, CH₂C₃F₇, CH₂CH₂C₃F₇, CH₂C₄F₉ and CH₂CH₂C₄F₉, with CF₃ being preferred.

L represents a divalent linking group, and examples thereof include -COO-, -OCO-, -CO-, -0-, -S-, -SO-, -S0₂-, -N(Ri)- (wherein Ri represents a hydrogen atom or an alkyl group), an alkylene group, a cycloalkylene group, an alkenylene group, and a divalent linking group formed by combining a plurality of these members. Above all, -COO-, -OCO-, -CO-, -S0₂-, -CON(Ri)-, -S0₂N(Ri)-, -CON(Ri)-alkylene group- and -COO-alkylene group- are preferred, and -COO-, -OCO-, -S0₂-, -CON(Ri)- and -S0₂N(Ri)- are more preferred. In the case where a plurality of L's are present, each L may be the same as or different from every other L.

Specific examples and preferred examples of the alkyl group for Ri are the same as specific examples and preferred examples described above for the alkyl group of Ri to Rio and Rx.

The cyclic organic group of A is not particularly limited as long as it has a cyclic structure, and examples thereof include an alicyclic group, an aryl group and a heterocyclic group (including not only those having aromaticity but also those having no aromaticity; including, for example, tetrahydropyran ring and lactone ring structures).

The alicyclic group may be monocyclic or polycyclic and is preferably a monocyclic cycloalkyl group such as cyclopentyl group, cyclohexyl group and cyclooctyl group, or a polycyclic cycloalkyl group such as norbornyl group, a norbornenyl group, tricyclodecanyl group (e.g., tricyclo[5.2.1.0²'⁶]decanyl group), tetracyclodecanyl group, tetracyclododecanyl group and adamantyl group. A nitrogen atom-containing alicyclic group such as piperidine group, decahydroquinoline group and decahydroisoquinoline group is also preferred. Above all, from the standpoint of suppressing diffusion in the film at the PEB (post-exposure baking) step and enhancing the exposure latitude, an alicyclic group having a bulky structure with a carbon number of 7 or more, such as norbornyl group, tricyclodecanyl group, tetracyclodecanyl group, tetracyclododecanyl group, adamantyl group, decahydroquinoline group and decahydroisoquinoline group, is preferred.

The aryl group includes a benzene ring, a naphthalene ring, a phenanthrene ring and an anthracene ring. Among these, naphthalene having low absorbance is preferred in view of absorbance for light at 1 3 nm.

The heterocyclic group includes a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, and a pyridine ring. Among these, a furan ring, a thiophene ring, and a pyridine ring are preferred.

The above-described cyclic organic group may have a substituent, and examples of the substituent include an alkyl group (may be linear, branched or cyclic, preferably having a carbon number of 1 to 12), an aryl group (preferably having a carbon number of 6 to 14), a hydroxy group, an alkoxy group, an ester group, an amido group, a urethane group, a ureido group, a thioether group, a sulfonamido group, and a sulfonic acid ester group.

Incidentally, the carbon constituting the cyclic organic group (the carbon contributing to ring formation) may be carbonyl carbon.

x is preferably from 1 to 8, more preferably from 1 to 4, still more preferably 1. y is preferably from 0 to 4, more preferably 0 or 1 , still more preferably 0. z is preferably from 0 to 8, more preferably from 0 to 4, still more preferably 1.

The preferred embodiment of the sulfonate anion structure of the compound (A), as an example shown by a hydrogen-added sulfonic acid structure, includes the following formula (Ilia). In the formula, Xf, Rn, Ri₂, L, A, y and z have the same meanings as those in formula (III).

Specific preferred examples of the compound (A) represented by formula (I) are illustrated below, but the present invention is not limited thereto. In the formulae, Me represents a methyl group.

The sulfonate anion represented by formula (III) or a salt thereof (for example, an onium salt and a metal salt) can be synthesized using a general sulfonic acid esterification reaction or a sulfonamidation reaction. For example, the compound may be obtained by a method of selectively reacting one sulfonyl halide moiety of a bis-sulfonyl halide compound with an amine, an alcohol, an amide compound or the like to form a sulfonamide bond, a sulfonic acid ester bond or a sulfonimide bond and then hydrolyzing the other sulfonyl halide moiety, or a method of ring-opening a cyclic sulfonic anhydride by an amine, an alcohol or an amide compound.

The salt of the sulfonic acid represented by formula (III) include a metal salt of sulfonic acid and an onium sulfonate. Examples of the metal in the metal salt of sulfonic acid include Na⁺, Li⁺ and ⁺. Examples of the onium cation in the onium sulfonate include an ammonium cation, a sulfonium cation, an iodonium cation, a phosphonium cation, and a diazonium cation.

The sulfonate anion represented by formula (III) or a salt thereof can be used for the synthesis of the compound (A) represented by formula (I).

The compound (A) can be synthesized by a method of salt-exchanging the sulfonate anion represented by formula (III) with a photoactive onium salt such as sulfonium salt corresponding to the sulfonium cation in formula (I).

In the actinic ray-sensitive or radiation-sensitive resin composition of the present invention, as for the compound (A), one compound may be used alone, or two or more compounds may be used in combination. The content of the compound (A) in the composition of the present invention is preferably from 0.1 to 30 mass%, more preferably from 0.5 to 25 mass%, still more preferably from 5 to 20 mass%, based on the entire solid content of the composition.

The compound (A) may be used in combination with an acid generator (hereinafter, sometimes referred to as "compound (A')) other than the compound (A).

The compound (Α') is not particularly limited but is preferably a compound represented by the following formula (ΖΓ), (ΖΙΓ) or (ΖΙΙΓ):

O N₂ O

R2O2 Z R₂₀₄_|1_R₂₀₅ R₂₀₆_1_JL __R207

R201— S— R₂03 (2T) ^z (ζι ΐ') o O (ΖΙ Ι Γ)

In formula (ΖΓ), each R₂₀i, R202 and R₂₀₃ independently represents an organic group.

The carbon number of the organic group as R₂₀i , R202 and R₂₀₃ is generally from 1 to 30, preferably from 1 to 20.

Two members out of R₂₀i to R₂₀₃ may combine to form a ring structure, and the ring may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond or a carbonyl group. The group formed by combining two members out of R₂₀i to R₂₀₃ includes an alkylene group (e.g., butylene, pentylene).

The organic group represented by R₂₀i, R₂₀₂ and R₂₀₃ includes, for example, the corresponding group in the later-described compound (ZI'-l).

The compound may be a compound having a plurality of structures represented by formula (ΖΓ). For example, the compound may be a compound having a structure where at least one of R₂₀i to R₂₀₃ in a compound represented by formula (ΖΓ) is bonded to at least one of R₂₀i to R₂₀₃ in another compound represented by formula (ΖΓ) through a single bond or a linking group.

Z^" represents a non-nucleophilic anion (an anion having an extremely low ability of causing a nucleophilic reaction).

Examples of Z^" include a sulfonate anion (such as aliphatic sulfonate anion, aromatic sulfonate anion and camphorsulfonate anion), a carboxylate anion (such as aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion), a sulfonylimide anion, a bis(alkylsulfonyl)imide anion, and a tris(alkylsulfonyl)methide anion.

The aralkyl group in the aralkylcarboxylate anion is preferably an aralkyl group having a carbon number of 7 to 12, and examples thereof include a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, and a naphthylbutyl group.

Examples of the sulfonylimide anion include saccharin anion. The alkyl group in the bis(alkylsulfonyl)imide anion and tris(alkylsulfonyl)methide anion is preferably an alkyl group having a carbon number of 1 to 5.

Two alkyl groups in the bis(alkylsulfonyl)imide anion may combine to form an alkylene group (preferably having a carbon number of 2 to 4) and may form a ring together with the imido group and two sulfonyl group.

Examples of the substituent which may be substituted on the alkyl group and the alkylene group formed by combining two alkyl groups in the bis(alkylsulfonyl)imide anion include a halogen atom, a halogen atom-substituted alkyl group, an alkoxy group, an alkylthio group, an alkyloxysulfonyl group, an aryloxysulfonyl group, and a cycloalkylaryloxysulfonyl group, with a fluorine and a fluorine atom-substituted alkyl group being preferred.

Other examples of Z^" include fluorinated phosphorus (e.g., PF₆ ^"), fluorinated boron (e.g., BF₄ ^~) and fluorinated antimony (e.g., SbF₆ ^").

In terms of the acid strength, pKa of the acid generated is preferably -1 or less so as to enhance the sensitivity.

A more preferred component (ΖΓ) is a compound (ΖΓ-1) described below.

The compound (ΖΓ-1) is an arylsulfonium compound where at least one of R₂₀i to R₂₀₃ in formula (ΖΓ) is an aryl group, that is, a compound having an arylsulfonium as the cation.

In the arylsulfonium compound, all of R₂₀i to R₂₀₃ may be an aryl group, or a part of R₂oi to R₂o3 may be an aryl group with the remaining being an alkyl group or a cycloalkyl group, but it is preferred that all of R₂₀i to R₂₀₃ are an aryl group.

Examples of the arylsulfonium compound include a triarylsulfoniuni compound, a diarylalkylsulfonium compound, an aryldialkylsulfonium compound, a diarylcycloalkylsulfonium compound, and an aryldicycloalkylsulfonium compound, with a triarylsulfonium compound being preferred.

The aryl group in the arylsulfonium compound is preferably a phenyl group or a naphthyl group, more preferably a phenyl group. The aryl group may be an aryl group having a heterocyclic structure containing an oxygen atom, a nitrogen atom, a sulfur atom or the like. Examples of the heterocyclic structure include a pyrrole residue group, a furan residue group, a thiophene residue group, an indole residue group, a benzofuran residue group, and a benzothiophene residue group. In the case where the arylsulfonium compound has two or more aryl groups, these two or more aryl groups may be the same or different.

The alkyl or cycloalkyl group which is contained, if desired, in the arylsulfonium compound is preferably a linear or branched alkyl group having a carbon number of 1 to 15 or a cycloalkyl group having a carbon number of 3 to 15, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

The aryl group, alkyl group and cycloalkyl group of R₂oi to R₂₀₃ may have, as a substituent, an alkyl group (for example, having a carbon number of 1 to 15), a cycloalkyl group (for example, having a carbon number of 3 to 15), an aryl group (for example, having a carbon number of 6 to 14), an alkoxy group (for example, having a carbon number of 1 to 15), a halogen atom, a hydroxyl group or a phenylthio group. The substituent is preferably a linear or branched alkyl group having a carbon number of 1 to 12, a cycloalkyl group having a carbon number of 3 to 12, or a linear, branched or cyclic alkoxy group having a carbon number of 1 to 12, more preferably an alkyl group having a carbon number of 1 to 4, or an alkoxy group having a carbon number of 1 to 4. The substituent may be substituted on any one of three members R₂₀i to R₂₀₃ or may be substituted on all of these three members. In the case where R₂₀i to R₂₀₃ are an aryl group, the substituent is preferably substituted on the p-position of the aryl group.

Formulae (ΖΙΓ) and (ΖΙΙΓ) are described below.

In formulae (ΖΙ ) and (ΖΙΙΓ), each of R₂₀₄ to R₂₀7 independently represents an aryl group, an alkyl group or a cycloalkyl group.

The aryl group, alkyl group and cycloalkyl group of R₂₀₄ to R₂₀₇ are the same as the aryl group, alkyl group and cycloalkyl group described for R₂₀i to R₂₀₃ in formula (ΖΓ-1).

The aryl group, alkyl group and cycloalkyl group of R₂₀₄ to R₂₀7 may have a substituent. Examples of the substituent include those of the substituent which may be substituted on the aryl group, alkyl group and cycloalkyl group of R₂₀i to R₂₀₃ in formula

(zr-i).

Z^" represents a non-nucleophilic anion, and examples thereof are the same as those of the non-nucleophilic anion of Z^" in formula (ΖΓ).

Other examples of the acid generator (Α') which can be used in combination with the acid generator of the present invention include compounds represented by the following formulae (ZIV), (ZV) and (ΖΥΓ):

In formulae (ZIV) to (ZVP), each of Ar₃ and Ar₄ independently represents an aryl group.

Each of R₂o8, R₂09 and R₂i ₀ independently represents an alkyl group, a cycloalkyl group or an aryl group.

A represents an alkylene group, an alkenylene group or an arylene group.

Specific examples of the aryl group of Ar₃, Ar₄, R₂₀₈, R₂₀9 and R_2t0 are the same as specific examples of the aryl group of R₂oi , R₂₀₂ and R₂₀₃ in formula (ΖΓ-1).

Specific examples of the alkyl group and cycloalkyl group of R₂₀8, R₂₀9 and R₂ i₀ are the same as specific examples of the alkyl group and cycloalkyl group of R_20], R₂₀₂ and R₂₀₃ in formula (ΖΓ-1).

The alkylene group of A includes an alkylene group having a carbon number of 1 to 12 (e.g., methylene group, ethylene group, propylene group, isopropylene group, butylene group, isobutylene group); the alkenylene group of A includes an alkenylene group having a carbon number of 2 to 12 (e.g., ethenylene group, propenylene group, butenylene group); and the arylene group of A includes an arylene group having a carbon number of 6 to 10 (e.g., phenylene group, tolylene group, naphthylene group).

Particularly preferred examples of the acid generator which can be used in combination with the acid generator of the present invention are illustrated below. 21

In the case of using the compound (A) and the compound (Α') in combination, the amount of acid generators used is, in terms of the mass ratio (compound (A)/compound (A')), usually from 99/1 to 20/80, preferably from 99/1 to 40/60, more preferably from 99/1 to 50/50.

[2] (B) Resin

The actinic ray-sensitive or radiation-sensitive resin composition of the present invention contains (B) a resin.

The resin (B) is preferably a resin capable of decomposing by the action of an acid to increase the solubility for an alkali developer (hereinafter, sometimes referred to as "acid-decomposable resin"). The acid-decomposable resin has a group capable of decomposing by the action of an acid to produce an alkali-soluble group (hereinafter, sometimes referred to as "acid-decomposable group"), on either one or both of the main chain and the side chain of the resin.

The resin (B) is preferably insoluble or sparingly soluble in an alkali developer.

The acid-decomposable group preferably has a structure where the alkali-soluble group is protected by a group capable of decomposing and leaving by the action of an acid.

Examples of the alkali-soluble group include a phenolic hydroxyl group, a carboxyl group, a fluorinated alcohol group, a sulfonic acid group, a sulfonamide group, a sulfonylimide group, an (alkylsulfonyl)(alkylcarbonyl)methylene group, an (alkylsulfonyl)(alkylcarbonyl)imide group, a bis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imide group, a bis(alkylsulfonyl)methylene group, a bis(alkylsulfonyl)imide group, a tris(alkylcarbonyl)methylene group and a tris(alkylsulfonyl)methylene group.

Preferred alkali-soluble groups include a carboxyl group, a fluorinated alcohol group (preferably hexafiuoroisopropanol group) and a sulfonic acid group.

The group preferred as the acid-decomposable group is a group where a hydrogen atom of the alkali-soluble group above is replaced by a group capable of leaving by the action of an acid.

Examples of the group capable of leaving by the action of an acid include -C(R₃₆)(R₃₇)(R₃₈), -C(R₃₆)(R₃₇)(OR₃₉) and -C(R₀₁)(R₀₂)(OR₃₉).

In the formulae, each of R₃₆ to R₃₉ independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group. R₃₆ and R₃₇ may combine with each other to form a ring.

Each of Roi and R₀₂ independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.

The acid-decomposable group is preferably a cumyl ester group, an enol ester group, an acetal ester group, a tertiary alkyl ester group or the like, more preferably a tertiary alkyl ester group.

The acid-decomposable group-containing repeating unit that the resin (B) may contain is preferably a repeating unit represented by the following formula (AI):

In formula (AI), Xai represents a hydrogen atom, a methyl group which may have a substituent, or a group represented by -CH2-R₉. R9 represents a hydroxyl group or a monovalent organic group. Examples of the monovalent organic group include an alkyl group having a carbon number of 5 or less and an acyl group having a carbon number of 5 or less. Of these, an alkyl group having a carbon number of 3 or less is preferred, and a methyl group is more preferred. Xai is preferably a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.

T represents a single bond or a divalent linking group.

Each of R i to Rx₃ independently represents an alkyl group (linear or branched) or a cycloalkyl group (monocyclic or polycyclic).

Two of Rxi to Rx₃ may combine to form a cycloalkyl group (monocyclic or polycyclic).

Examples of the divalent linking group of T include an alkylene group, a -COO-Rt- group, a -O-Rt- group and the like. In the formulae, Rt represents an alkylene group or a cycloalkylene group.

T is preferably a single bond or a -COO-Rt- group. Rt is preferably an alkylene group having a carbon number of 1 to 5, more preferably a -CH₂- group, -(CH₂)₂- group or a -(CH₂)₃- group.

The alkyl group of Rxi to Rx₃ is preferably an alkyl group having a carbon number of 1 to 4, such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and tert-butyl group.

The cycloalkyl group of Rxi to Rx₃ is preferably a monocyclic cycloalkyl group such as cyclopentyl group and cyclohexyl group, or a polycyclic cycloalkyl group such as norbornyl group, tetracyclodecanyl group, tetracyclododecanyl group and adamantyl group.

The cycloalkyl group formed by combining two of Rxi to Rx₃ is preferably a monocyclic cycloalkyl group such as cyclopentyl group and cyclohexyl group, Or a polycyclic cycloalkyl group such as norbornyl group, tetracyclodecanyl group, tetracyclododecanyl group and adamantyl group. Above all, a monocyclic cycloalkyl group having a carbon number of 5 to 6 is preferred.

An embodiment where Rxi is a methyl group or an ethyl group and Rx₂ and Rx₃ are combined to form the above-described cycloalkyl group is preferred.

Each of the groups above may have a substituent, and examples of the substituent include an alkyl group (having a carbon number of 1 to 4), a halogen atom, a hydroxyl group, an alkoxy group (having a carbon number of 1 to 4), a carboxyl group and an alkoxycarbonyl group (having a carbon number of 2 to 6). The carbon number is preferably 8 or less.

The content of the repeating unit having an acid-decomposable group is preferably from 20 to 70 mol%, more preferably from 30 to 60 mol%, based on all repeating units constituting the resin.

Specific preferred examples of the repeating unit having an acid-decomposable group are illustrated below, but the present invention is not limited thereto.

In specific examples, each of Rx and Xai represents a hydrogen atom, CH₃, CF₃ or CH₂OH, and each of Rxa and Rxb represents an alkyl group having a carbon number of 1 to 4. Z represents a substituent containing a polar group, and when a plurality of Z's are present, each is independent from every others, p represents 0 or a positive integer. Specific examples and preferred examples of Z are the same as specific examples and preferred examples of Rio in formula (II- 1) described later.

The resin (B) is more preferably a resin containing, as the repeating unit represented by formula (AI), at least either a repeating unit represented by the following formula (I) or a repeatin unit represented by the following formula (II).

(I) (II)

In formulae (I) and (II), each of Ri and R₃ independently represents a hydrogen atom, a methyl group which may have a substituent, or a group represented by -CH₂-R9. R₉ represents a monovalent organic group.

Each of R₂, R4, R₅ and R₆ independently represents an alkyl group or a cycloalkyl group.

R represents an atomic group necessary for forming an alicyclic structure together with the carbon atom.

Each of Ri and R₃ is preferably a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group. Specific examples and preferred examples of the monovalent organic group in R₉ are the same as those described for R9 in formula (AI).

The alkyl group in R₂ may be linear or branched and may have a substituent.

The cycloalkyl group in R₂ may be monocyclic or polycyclic and may have a substituent.

R₂ is preferably an alkyl group, more preferably an alkyl group having a carbon number of 1 to 10, still more preferably an alkyl group having a carbon number of 1 to 5, and examples thereof include a methyl group and an ethyl group and the like.

R represents an atomic group necessary for forming an alicyclic structure together with the carbon atom. The alicyclic structure formed by R together with the carbon atom is preferably a monocyclic alicyclic structure, and the carbon number thereof is preferably from 3 to 7, more preferably 5 or 6.

R3 is preferably a hydrogen atom or a methyl group, more preferably a methyl group.

The alkyl group in R_t, R₅ and R₆ may be linear or branched and may have a substituent. The alkyl group is preferably an alkyl group having a carbon number of 1 to 4, such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and tert-butyl group.

The cycloalkyl group in R4, R₅ and R₆ may be monocyclic or polycyclic and may have a substituent. The cycloalkyl group is preferably a monocyclic cycloalkyl group such as cyclopentyl group and cyclohexyl group, or a polycyclic cycloalkyl group such as norbornyl group, tetracyclodecanyl group, tetracyclododecanyl group and adamantyl group.

Examples of the repeating unit represented by formula (I) include for example a repeating unit represented by the following formula (1-a):

In the formula, Ri and R₂ have the same meanings as those in formula (I).

The repeating unit represented by formula (II) is preferably a repeating unit represented b the following formula (II- 1):

In formula (II-l), R₃ to R₅ have the same meanings as those in formula (II).

Rio represents a polar group-containing substituent. In the case where a plurality of Rio's are present, these may be the same or different. Examples of the polar group-containing substituent include a hydroxyl group, a cyano group, an amino group, an alkylamide group, a sulfonamide group itself, and a linear or branched alkyl group or cycloalkyl group having at least one of the groups above. An alkyl group having a hydroxyl group is preferred, and a branched alkyl group having a hydroxyl group is more preferred. The branched alkyl group is preferably an isopropyl group.

p represents an integer of 0 to 15. p is preferably an integer of 0 to 2, more preferably 0 or 1.

The acid-decomposable resin is preferably a resin containing, as the repeating unit represented by formula (AI), at least either one of a repeating unit represented by formula (I) and a repeating unit represented by formula (II). In another embodiment, the resin is preferably a resin containing, as the repeating unit represented by formula (AI), at least two kinds of repeating units represented by formula (I).

As for the repeating unit having an acid-decomposable group of the resin (B), one kind may be used, or two or more kinds may be used in combination. In the case of combination use, preferred examples of the combination are illustrated below. In the rmulae below, each R independently represents a hydro en atom or a meth l rou .

The resin (B) preferably contains a repeating unit having a lactone structure or a sultone (cyclic sulfonic acid ester) structure.

As the lactone group or sultone group, any may be used as long as it has a lactone structure or a sultone structure, but the structure is preferably a 5- to 7-membered ring lactone or sultone structure, and a structure where another ring structure is fused to a 5- to 7-membered ring lactone or sultone structure in the form of forming a bicyclo or spiro structure, is preferred. The resin more preferably contains a repeating unit having a lactone or sultone structure represented by any one of the following formulae (LCl-1) to (LCI- 17), (SLl-1) and (SL1-2). The lactone or sultone structure may be bonded directly to the main chain. Preferred lactone or sultone structures are (LCI -I), (LCI -4), (LCl-5) and (LCI -8), with (LCI -4) being more preferred. By using a specific lactone or sultone structure, LWR and development defect are improved.

The lactone structure moiety or sultone structure moiety may or may not have a substituent (Rb₂). Preferred examples of the substituent (Rb₂) include an alkyl group having a carbon number of 1 to 8, a cycloalkyl group having a carbon number of 4 to 7, an alkoxy group having a carbon number of I to 8, an alkoxycarbonyl group having a carbon number of 2 to 8, a carboxyl group, a halogen atom, a hydroxyl group, a cyano group, and an acid-decomposable group. Among these, an alkyl group having a carbon number of 1 to 4, a cyano group and an acid-decomposable group are more preferred. n₂ represents an integer of 0 to 4. When n₂ is an integer of 2 or more, each substituent (Rb₂) may be the same as or different from every other substituents (Rb₂), and also, the plurality of substituents (Rb₂) may combine with each other to form a ring.

The resin (B) preferably contains a repeating unit having a lactone structure or a sultone structure represented by the following formula (III):

In formula (III), A represents an ester bond (a group represented by -COO-) or an amido bond (a group represented by -CONH-).

R₀ represents, when a plurality of R₀'s are present, each independently represents, an alkylene group, a cycloalkylene group or a combination thereof.

Z represents, when a plurality of Z's are present, each independently represents, an ether bond, an ester bond, an amide bond, a urethane bond

(a group represented by or

or a urea bond

R I R

— N-^-N—

(a group represented by ),

wherein R represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group.

Rg represents a monovalent organic group having a lactone structure or a sultone structure. n is the repetition number of the structure represented by -R₀-Z- and represents an integer of 0 to 2.

R₇ represents a hydrogen atom, a halogen atom or an alkyl group.

The alkylene group and cycloalkylene group of R₀ may have a substituent.

Z is preferably an ether bond or an ester bond, more preferably an ester bond.

The alkyl group of R₇ is preferably an alkyl group having a carbon number of 1 to 4, more preferably a methyl group or an ethyl group, still more preferably a methyl group. The alkylene group and cycloalkylene group of R₀ and the alkyl group in R₇ each may be substituted, and examples of the substituent include a halogen atom such as fluorine atom, chlorine atom and bromine atom, a mercapto group, a hydroxy group, an alkoxy group such as methoxy group, ethoxy group, isopropoxy group, tert-butoxy group and benzyloxy group, and an acetoxy group such as acetyloxy group and propionyloxy group. R₇ is preferably a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.

The chain alkylene group in Ro is preferably a chain alkylene group having a carbon number of 1 to 10, more preferably a carbon number of 1 to 5, and examples thereof include a methylene group, an ethylene group and a propylene group. The cycloalkylene group is preferably a cycloalkylene group having a carbon number of 3 to 20, and examples thereof include a cyclohexylene group, a cyclopentylene group, a norbornylene group and an adamantylene group. For bringing out the effects of the present invention, a chain alkylene group is more preferred, and a methylene group is still more preferred.

The substituent having a lactone or sultone structure represented by Rg is not limited as long as it has a lactone or sultone structure. Specific examples thereof include the lactone or structures represented by formulae (LCl-1) to (LCl-17), (SLl-1) and (SLl-2), and among these, the structure represented by (LCI -4) is preferred. Structures where n₂ in (LCl-1) to (LCl-17), (SLl-1) and (SLl-2) is 2 or less are more preferred.

R₈ is preferably a monovalent organic group having an unsubstituted lactone or sultone structure, or a monovalent organic group having a lactone or sultone structure containing a methyl group, a cyano group or an alkoxycarbonyl group as a substituent, more preferably a monovalent organic group having a lactone (cyanolactone) or sultone (cyanosultone) structure containing a cyano group as a substituent.

Specific examples of the repeating unit containing a group having a lactone or sultone structure represented by formula (III) are illustrated below, but the present invention is not limited thereto. In specific examples, R represents a hydrogen atom, an alkyl group which may have a substituent, or a halogen atom, preferably a hydrogen atom, a methyl group, a hydroxymethyl group or an acetoxymethyl group.

In the following formulae, Me represents a methyl group.

The lactone or sultone structure-containing repeating unit is more preferably a re eating unit represented by the following formula (III- 1 ) or (ΙΙΙ-Γ):

In formulae (III- 1 ) and (ΙΠ- ), R₇, A, R₀, Z and n have the same meanings as in formula (III).

R₇', A', Ro', Z' and n' have the same meanings as R₇, A, R₀, Z and n in formula (III), respectively.

R9 represents, when a plurality of R9S are present, each independently represents, an alkyl group, a cycloalkyl group, an alkoxycarbonyl group, a cyano group, a hydroxyl group or an alkoxy group, and when a plurality of R9S are present, two members thereof may combine to form a ring.

R₉' represents, when a plurality of R₉'s are present, each independently represents, an alkyl group, a cycloalkyl group, an alkoxycarbonyl group, a cyano group, a hydroxyl group or an alkoxy group, and when a plurality of Rjs are present, two members thereof may combine to form a ring. Each of X and X' independently represents an alkylene group, an oxygen atom or a sulfur atom.

Each of m and m' is the number of substituents and independently represents an integer of 0 to 5. Each of m and m' is independently preferably 0 or 1.

The alkyl group of R9 and R9' is preferably an alkyl group having a carbon number of 1 to 4, more preferably a methyl group or an ethyl group, and most preferably a methyl group. Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group. Examples of the alkoxycarbonyl group include a methoxycarbonyl group, an ethoxycarbonyl group, an n-butoxycarbonyl group and a tert-butoxycarbonyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group and a butoxy group. These groups may have a substituent, and the substituent includes a hydroxy group, an alkoxy group such as methoxy group and ethoxy group, a cyano group, and a halogen atom such as fluorine atom. Each of R9 and R9' is preferably a methyl group, a cyano group or an alkoxycarbonyl group, more preferably a cyano group.

Examples of the alkylene group of X and X' include a methylene group and an ethylene group. Each of X and X' is preferably an oxygen atom or a methylene group, more preferably a methylene group.

When each of m and m' is an integer of 1 or more, at least one R₉ and R₉' is preferably substituted on the oc-position or β-position, more preferably on the cc-position, of the carbonyl group of the lactone.

Specific examples of the repeating unit having a lactone structure-containing group or a sultone structure represented by formula (III- 1) or (ΙΙΙ- ) are illustrated below, but the present invention is not limited thereto. In specific examples, R represents a hydrogen atom, an alkyl group which may have a substituent, or a halogen atom, preferably a hydrogen atom, a methyl group, a hydroxymethyl group or an acetoxymethyl group.

The content of the repeating unit represented by formula (III) is, in the case of containing a plurality of kinds or repeating units, as a total thereof, preferably from 15 to 60 mol%, more preferably from 20 to 60 mol%, still more preferably from 30 to 50 mol%, based on all repeating units in the resin.

In one embodiment, the unit represented by formula (III) may be a repeating unit represented by the following formula (ΑΙΓ):

— V In formula (ΑΙΓ), bo represents a hydrogen atom, a halogen atom or an alkyl group having a carbon number of 1 to 4. Preferred examples of the substituent which may be substituted on the alkyl group of Rbo include a hydroxyl group and a halogen atom. The halogen atom of Rbo includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Rb₀ is preferably a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group, more preferably a hydrogen atom or a methyl group.

V represents a group having a structure represented by any one of formulae (LCl-1) to (LCl-17), (SLl-1) and (SL1-2).

The resin (B) may contain a repeating unit having the above-described lactone or sultone structure other than the unit represented by formula (III).

Specific examples of the repeating unit having a lactone group or a sultone group include the followings, in addition to specific examples illustrated above, but the present invention is not limited thereto.

(In the formulae, Rx represents H, CH₃, CH₂OH or CF₃.)

(In the formulae, Rx represents H, CH₃, CH₂OH or CF₃.)

(In the formulae, Rx represents H, CH₃, CH₂OH or CF₃.)

Among these specific examples, particularly preferred repeating units include the following repeating units. By selecting an optimal lactone or sultone group, the pattern profile and the iso/dense bias are improved.

(In the formulae, Rx represents H, CH₃, CH₂OH or CF₃.)

The repeating unit having a lactone or sultone group usually has an optical isomer, but any optical isomer may be used. One optical isomer may be used alone, or a mixture of a plurality of optical isomers may be used. In the case of mainly using one optical isomer, the optical purity (ee) thereof is preferably 90% or more, more preferably 95% or more.

The content of the repeating unit having a lactone or sultone structure other than the repeating unit represented by formula (III) is, in the case of containing a plurality of kinds of repeating units, as a total thereof, preferably from 15 to 60 mol%, more preferably from 20 to 50 mol%, still more preferably from 30 to 50 mol%, based on all repeating units in the resin.

Also, two or more kinds of lactone or sultone repeating units selected from formula (III) may be used in combination so as to increase the effects of the present invention. In the case of combination use, it is preferred that out of formula (III), two or more lactone or sultone repeating units where n is 1 are selected and used in combination.

The resin (B) preferably contains a repeating unit having a hydroxyl group or a cyano group, other than formulae (AI) and (III). Thanks to this repeating unit, the adherence to substrate and the affinity for developer are enhanced. The repeating unit having a hydroxyl group or a cyano group is preferably a repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group and preferably has no acid-decomposable group. The alicyclic hydrocarbon structure in the alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably an adamantyl group, a diamantyl group or a norbornyl group. The alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group is preferably a partial structure represented by the following formulae (Vila) to (Vlld):

(V i l a ) (V I I b ) (V I I c ) (V I I d )

In formulae (Vila) to (VIIc), each of R₂c to ^c independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, at least one of R₂c to R4C represents a hydroxyl group or a cyano group. A structure where one or two members out of R₂c to R4C are a hydroxyl group with the remaining being a hydrogen atom is preferred. In formula (Vila), it is more preferred that two members out of R₂c to R4C are a hydroxyl group and the remaining is a hydrogen atom.

The repeating unit having a partial structure represented by formulae (Vila) to (Vlld) includes repeating units represented by the following formulae (Alia) to (Alld):

In formulae (Alia) to (Alld), Ric represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.

R₂c to C have the same meanings as R₂c to R4C in formulae (Vila) to (VIIc).

The content percentage of the repeating unit having a hydroxyl group or a cyano group is preferably from 5 to 40 mol%, more preferably from 5 to 30 mol%, still more preferably from 10 to 25 mol%, based on all repeating units in the resin (B). Specific examples of the repeating unit having a hydroxy group or a cyano group are illustrated below, but the present invention is not limited thereto.

The resin for use in the actinic ray-sensitive or radiation-sensitive resin composition of the present invention may contain a repeating unit having an alkali-soluble group. The alkali-soluble group includes a carboxyl group, a sulfonamide group, a sulfonylimide group, a bissulfonylimide group, and an aliphatic alcohol substituted with an electron-withdrawing group at the a-position (for example, hexafluoroisopropanol group), and it is preferred to contain a repeating unit having a carboxyl group. By virtue of containing a repeating unit having an alkali-soluble group, the resolution increases in the usage of forming contact holes. As for the repeating unit having an alkali-soluble group, all of a repeating unit where an alkali-soluble group is directly bonded to the main chain of the resin, such as repeating unit by an acrylic acid or a methacrylic acid, a repeating unit where an alkali-soluble group is bonded to the main chain of the resin through a linking group, and a repeating unit where an alkali-soluble group is introduced into the polymer chain terminal by using an alkali-soluble group-containing polymerization initiator or chain transfer agent at the polymerization, are preferred. The linking group may have a monocyclic or polycyclic cyclohydrocarbon structure. In particular, a repeating unit by an acrylic acid or a methacrylic acid is preferred.

The content of the repeating unit having an alkali-soluble group is preferably from 0 to 20 mol%, more preferably from 3 to 15 mol%, still more preferably from 5 to 10 mol%, based on all repeating units in the resin (B).

Specific examples of the repeating unit having an alkali-soluble group are illustrated below, but the present invention is not limited thereto.

In specific examples, Rx represents H, CH₃, CH₂OH or CF₃.

The resin (B) may further contain a repeating unit having an alicyclic hydrocarbon structure free from a polar group (for example, the above-described alkali-soluble group, a hydroxyl group or a cyano group) and not exhibiting acid decomposability. Such a repeating unit includes a repeating unit represented by the following formula (IV):

In formula (IV) above, R₅ represents a hydrocarbon group having at least one cyclic structure and having no polar group.

Ra represents a hydrogen atom, an alkyl group, or a -CH₂-0-Ra₂ group, wherein Ra₂ represents a hydrogen atom, an alkyl group or an acyl group. Ra is preferably a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group, more preferably a hydrogen atom or a methyl group.

The cyclic structure contained in R₅ includes a monocyclic hydrocarbon group and a polycyclic hydrocarbon group. Examples of the monocyclic hydrocarbon group include a cycloalkyl group having a carbon number of 3 to 12, such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group, and a cycloalkenyl group having a carbon number of 3 to 12, such as cyclohexenyl group. The monocyclic hydrocarbon group is preferably a monocyclic hydrocarbon group having a carbon number of 3 to 7, more preferably a cyclopentyl group or a cyclohexyl group.

The polycyclic hydrocarbon group includes a ring assembly hydrocarbon group and a crosslinked cyclic hydrocarbon group. Examples of the ring assembly hydrocarbon group include a bicyclohexyl group and a perhydronaphthalenyl group. Examples of the crosslinked cyclic hydrocarbon ring include a bicyclic hydrocarbon ring such as pinane ring, bornane ring, norpinane ring, norbornane ring and bicyclooctane ring (e.g., bicyclo[2.2.2]octane ring, bicyclo[3.2.1]octane ring), a tricyclic hydrocarbon ring such as homobledane ring, adamantane ring, tricyclo[5.2.1.0²'⁶]decane ring and tricyclo[4.3.1.1 2 ' 5 ]undecane ring, and a tetracyclic hydrocarbon ring such as tetracyclo[4.4.0.1²'⁵. l⁷'¹⁰]dodecane ring and perhydro- l,4-methano-5,8-methanonaphthalene ring. The crosslinked cyclic hydrocarbon ring also includes a condensed cyclic hydrocarbon ring, for example, a condensed ring formed by fusing a plurality of 5- to 8-membered cycloalkane rings, such as perhydronaphthalene (decalin) ring, perhydroanthracene ring, perhydrophenathrene ring, perhydroacenaphthene ring, perhydrofluorene ring, perhydroindene ring and perhydrophenalene ring.

Preferred examples of the crosslinked cyclic hydrocarbon ring include a norbornyl group, an adamantyl group, a bicyclooctanyl group and a tricycle[5,2,l,0²'⁶]decanyl group. Of these crosslinked cyclic hydrocarbon rings, a norbornyl group and an adamantyl group are more preferred.

These alicyclic hydrocarbon groups may have a substituent, and preferred examples of the substituent include a halogen atom, an alkyl group, a hydroxyl group in which a hydrogen atom is replaced, and an amino group in which a hydrogen atom is replaced. The halogen atom is preferably bromine atom, chlorine atom or fluorine atom, and the alkyl group is preferably a methyl group, an ethyl group, a butyl group or a tert-butyl group. This alkyl group may further have a substituent, and the substituent which the alkyl group may further have includes a halogen atom, an alkyl group, a hydroxyl group in which a hydrogen atom is replaced, and an amino group in which a hydrogen atom is replaced.

Examples of the group in which a hydrogen atom is replaced include an alkyl group, a cycloalkyl group, an aralkyl group, a substituted methyl group, a substituted ethyl group, an acyl group, an alkoxycarbonyl group and an aralkyloxycarbonyl group. The alkyl group is preferably an alkyl group having a carbon number of 1 to 4; the substituted methyl group is preferably a methoxymethyl group, a methoxythiomethyl group, a benzyloxymethyl group, a tert-butoxymethyl group or a 2-methoxyethoxymethyl group; the substituted ethyl group is preferably a 1-ethoxyethyl group or a 1 -methyl- 1-methoxyethyl group; the acyl group is preferably an aliphatic acyl group having a carbon number of 1 to 6, such as formyl group, acetyl group, propionyl group, butyryl group, isobutyryl group, valeryl group and pivaloyl group; and the alkoxycarbonyl group is, for example, an alkoxycarbonyl group having a carbon number of 2 to 4.

The resin (B) for use in the present invention may or may not contain a repeating unit having a polar group-free alicyclic hydrocarbon structure and not exhibiting acid decomposability, but in the case of containing the repeating unit, the content thereof is preferably from 1 to 40 mol%, more preferably from 2 to 20 mol%, based on all repeating units in the resin (B).

Specific examples of the repeating unit having a polar group-free alicyclic hydrocarbon structure and not exhibiting acid decomposability are illustrated below, but the present invention is not limited thereto. In the formulae, Ra represents H, CH₃, CH₂OH or

The resin (B) for use in the composition of the present invention may contain, in addition to the above-described repeating structural units, various repeating structural units for the purpose of controlling the dry etching resistance, suitability for standard developer, adherence to substrate, resist profile and properties generally required of a resist, such as resolution, heat resistance and sensitivity.

Examples of such a repeating structural unit include, but are not limited to, repeating structural units corresponding to the monomers described below.

Thanks to these repeating units, the performance required of the resin to be used in the composition of the present invention, particularly

(1) solubility in coating solvent,

(2) film-forming property (glass transition temperature),

(3) alkali developability,

(4) film loss (selection of hydrophilic, hydrophobic or alkali-soluble group),

(5) adherence of unexposed area to substrate, (6) dry etching resistance

and the like, can be subtly controlled.

Examples of the monomer include a compound having one addition-polymerizable unsaturated bond selected from acrylic acid esters, methacrylic acid esters, acrylamides, methacrylamides, allyl compounds, vinyl ethers and vinyl esters.

Other than these, an addition-polymerizable unsaturated compound copolymerizable with the monomers corresponding to the above-described various repeating structural units may be copolymerized.

In the resin (B) for use in the composition of the present invention, the molar ratio of respective repeating structural units contained can be appropriately set to control the dry etching resistance of resist, suitability for standard developer, adherence to substrate, resist profile and performances generally required of a resist, such as resolution, heat resistance and sensitivity.

In the case where the composition of the present invention is used for ArF exposure, in view of transparency to ArF light, the resin (B) for use in the composition of the present invention preferably has substantially no aromatic group. More specifically, the proportion of the aromatic group-containing repeating unit in all repeating units of the resin (B) is preferably 5 mol% or less, more preferably 3 mol% or less, and ideally 0 mol%, that is, not to contain a repeating unit having an aromatic group. Also, the resin (B) preferably has a monocyclic or polycyclic alicyclic hydrocarbon structure.

Also, in view of compatibility with the later-described hydrophobic resin that is a second resin, the resin (B) preferably contains no fluorine atom and no silicon atom.

The resin (B) for use in the composition of the present invention is preferably a resin where all repeating units are composed of a (meth)acrylate-based repeating unit. In this case, all repeating units may be a methacrylate-based repeating unit, all repeating units may be an acrylate-based repeating unit, or all repeating units may be composed of a methacrylate-based repeating unit and an acrylate-based repeating unit, but the content of the acrylate-based repeating unit is preferably 50 mol% or less based on all repeating units. A copolymerized polymer containing from 20 to 50 mol% of an acid decomposable group-containing (me h)acrylate-based repeating unit, from 20 to 50 mol% of a lactone group-containing (meth)acrylate-based repeating unit, from 5 to 30 mol% of a (meth)acrylate-based repeating unit having an alicyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group, and from 0 to 20 mol% of other (meth)acrylate-based repeating units, is also preferred. In the case of irradiating the composition of the present invention with rF excimer laser light, electron beam, X-ray or high-energy beam at a wavelength of 50 nm or less (e.g., EUV), the resin (B) preferably further contains a hydroxystyrene-based repeating unit. It is more preferred to contain a hydroxystyrene-based repeating unit, a hydroxystyrene-based repeating unit protected by an acid-decomposable group, and an acid-decomposable repeating unit such as tertiary alkyl (meth)acrylate.

Preferred examples of the hydroxystyrene-based repeating unit having an acid-decomposable group include repeating units composed of a tert-butoxycarbonyloxystyrene, a 1-alkoxyethoxystyrene or a tertiary alkyl (meth)acrylate. Repeating units composed of a 2-alkyl-2-adamantyl (meth)acrylate or a dialkyl(l-adamantyl)methyl (meth)acrylate are more preferred.

The resin (B) in the present invention can be synthesized by a conventional method (for example, radical polymerization). Examples of the general synthesis method include a batch polymerization method of dissolving monomer species and an initiator in a solvent and heating the solution, thereby effecting the polymerization, and a dropping polymerization method of adding dropwise a solution containing monomer species and an initiator to a heated solvent over 1 to 10 hours. A dropping polymerization method is preferred. Examples of the reaction solvent include ethers such as tetrahydrofuran, 1 ,4-dioxane, diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, an ester solvent such as ethyl acetate, an amide solvent such as dimethyl formamide and dimethylacetamide, and the later-described solvent capable of dissolving the composition of the present invention, such as propylene glycol monomethyl ether acetate (PGMEA, another name: l-methoxy-2-acetoxypropane), propylene glycol monomethyl ether (PGME, another name: l-methoxy-2-propanol) and cyclohexanone. The polymerization is more preferably performed using the same solvent as the solvent used in the actinic ray-sensitive or radiation-sensitive resin composition of the present invention. By the use of the same solvent, production of particles during storage can be suppressed.

The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon. As for the polymerization initiator, the polymerization is started using a commercially available radical initiator (e.g., azo-based initiator, peroxide). The radical initiator is preferably an azo-based initiator, and an azo-based initiator having an ester group, a cyano group or a carboxyl group is preferred. Preferred examples of the initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile and dimethyl 2,2'-azobis(2-methylpropionate). The initiator is added additionally or in parts, if desired. After the completion of reaction, the reaction product is poured in a solvent, and the desired polymer is collected by a method such as powder or solid recovery. The concentration at the reaction is from 5 to 50 mass%, preferably from 10 to 30 mass%, and the reaction temperature is usually from 10 to 150°C, preferably from 30 to 120°C, more preferably from 60 to 100°C. (In this specification, mass ratio is equal to weight ratio.)

The weight average molecular weight of the resin (B) for use in the present invention is preferably from 1,000 to 200,000, more preferably from 2,000 to 20,000, still more preferably from 3,000 to 15,000, yet still more preferably from 3,000 to 10,000, in terms of polystyrene by the GPC method. When the weight average molecular weight is from 1 ,000 to 200,000, reduction in the heat resistance and dry etching resistance can be more avoided and at the same time, the film-forming property can be prevented from deterioration due to impairment of developability or increase in the viscosity.

The dispersity (molecular weight distribution) is usually from 1.0 to 3.0, preferably from 1.0 to 2.6, more preferably from 1.0 to 2.0, still more preferably from 1.4 to 2.0. As the molecular weight distribution is smaller, the resolution and resist profile are more excellent, the side wall of the resist pattern is smoother, and the roughness is more improved.

In the present invention, the blending ratio of the resin (B) in the composition as a whole is preferably from 30 to 99 mass%, more preferably from 60 to 95 mass%, based on the entire solid content.

As for the resin of the present invention, one kind may be used or a plurality of kinds may be used in combination.

Incidentally, a resin other than the resin (B) for use in the present invention may be used in combination as long as the effects of the present invention are not impaired. The resin other than the resin (B) for use in the present invention includes an acid-decomposable resin which may contain the above-described repeating units that can be contained in the resin (B), and other known acid-decomposable resins.

[3] Hydrophobic resin

The actinic ray-sensitive or radiation-sensitive resin composition of the present invention, particularly when applied to immersion exposure, may contain a hydrophobic resin having at least either a fluorine atom or a silicon atom (hereinafter sometimes referred to as a "hydrophobic resin (HR)"). The hydrophobic resin (HR) is unevenly distributed to the surface layer of the film and when the immersion medium is water, can enhance the static/dynamic contact angle on the resist film surface for water as well as the followability of the immersion liquid.

The hydrophobic resin (HR) is, as described above, unevenly distributed to the interface but unlike a surfactant, need not have necessarily a hydrophilic group in the molecule and may not contribute to uniform mixing of polar/nonpolar substances.

The hydrophobic resin typically contains a fluorine atom and/or a silicon atom. The fluorine atom and/or silicon atom in the hydrophobic resin (HR) may be contained in the main chain of the resin or contained in the side chain.

In the case where the hydrophobic resin contains a fluorine atom, the resin preferably contains, as the fluorine atom-containing partial structure, a fluorine atom-containing alkyl group, a fluorine atom-containing cycloalkyl group or a fluorine atom-containing aryl group.

The fluorine atom-containing alkyl group is a linear or branched alkyl group with at least one hydrogen atom being replaced by a fluorine atom, and the alkyl group preferably has a carbon number of 1 to 10, more preferably a carbon number of 1 to 4, and may further have a substituent other than fluorine atom.

The fluorine atom-containing cycloalkyl group is a monocyclic or polycyclic cycloalkyl group with at least one hydrogen atom being replaced by a fluorine atom and may further have a substituent other than fluorine atom.

The fluorine atom-containing aryl group includes an aryl group such as phenyl group and naphthyl group, with at least one hydrogen atom being replaced by a fluorine atom, and may further have a substituent other than fluorine atom.

Preferred examples of the fluorine atom-containing alkyl group, fluorine atom-containing cycloalkyl group and fluorine atom-containing aryl group include a group represented by any one of the following formulae (F2) to (F4), but the present invention is not limited thereto.

(F2) (F3) (F4)

In formulae (F2) to (F4), each of R₅₇ to R^ independently represents a hydrogen atom, a fluorine atom or a (linear or branched) alkyl group, provided that at least one of R ₇ to R₆i, at least one of R ₂ to R ₄ and at least one of R₆₅ to R₆₈ are independently a fluorine atom or an alkyl group (preferably having a carbon number of 1 to 4) with at least one hydrogen atom being replaced by a fluorine atom.

It is preferred that all of R₅₇ to R^i and R₆₅ to R67 are a fluorine atom. Each of Re₂, R₆3 and R ₈ is preferably a fluoroalkyl group (preferably having a carbon number of 1 to 4), more preferably a perfluoroalkyl group having a carbon number of 1 to 4. When R ₂ and R« are perfluoroalkyl groups, it is preferred that R₆ is a hydrogen atom R^ and R₆₃ may combine with each other to form a ring.

Specific examples of the group represented by formula (F2) include p-fluorophenyl group, pentafluorophenyl group and 3,5-di(trifluoromethyl)phenyl group.

Specific examples of the group represented by formula (F3) include trifluoromethyl group, pentafluoropropyl group, pentafluoroethyl group, heptafluorobutyl group, hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro(2-methyl)isopropyl group, nonafluorobutyl group, octafluoroisobutyl group, nonafluorohexyl group, nonafluoro-tert-butyl group, perfluoroisopentyl group, perfluorooctyl group, perfluoro(trimethyl)hexyl group, 2,2,3, 3-tetrafluorocyclobutyl group and perfluorocyclohexyl group. Among these, hexafluoroisopropyl group, heptafluoroisopropyl group, hexafluoro(2-methyl)isopropyl group, octafluoroisobutyl group, nonafluoro-tert-butyl group and perfluoroisopentyl group are preferred, and hexafluoroisopropyl group and heptafluoroisopropyl group are more preferred.

Specific examples of the group represented by formula (F4) include -C(CF₃)₂OH, -C(C₂F₅)₂OH, -C(CF₃)(CH₃)OH and -CH(CF₃)OH, with -C(CF₃)₂OH being preferred. The fluorine-containing partial structure may be directly bonded to the main chain or may be bonded to the main chain through a group selected from the group consisting of an alkylene group, a phenylene group, an ether bond, a thioether bond, a carbonyl group, an ester bond, an amide bond, a urethane bond and a ureylene bond, or a group formed by combining two or more thereof.

As for the repeating unit having a fluorine atom, those shown below are preferred.

( C— I a ) ( C - I b ) ( C - I c ) ( C - I d )

In the formulae, each of R₁₀ and Rn independently represents a hydrogen atom, a fluorine atom or an alkyl group. The alkyl group is preferably a linear or branched alkyl group having a carbon number of 1 to 4 and may have a substituent, and the alkyl group having a substituent includes, in particular, a fluorinated alkyl group.

Each of W₃ to W independently represents an organic group having at least one or more fluorine atoms. Specific examples thereof include the atomic groups of (F2) to (F4).

Other than these, the hydrophobic resin (C) may contain a unit shown below as the repeating unit having a fluorine atom.

(C-II) (C-III)

In the formulae, each of R₄ to R₇ independently represents a hydrogen atom, a fluorine atom or an alkyl group. The alkyl group is preferably a linear or branched alkyl group having a carbon number of 1 to 4 and may have a substituent, and the alkyl group having a substituent includes, in particular, a fluorinated alkyl group. However, at least one of R to R₇ represents a fluorine atom. A pair of R and R₅ or a pair of R₆ and R₇ may form a ring.

W₂ represents an organic group containing at least one fluorine atom. Specific examples thereof include the atomic groups of (F2) to (F4).

L₂ represents a single bond or a divalent linking group. The divalent linking group is a substituted or unsubstituted arylene group, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, -0-, -S0₂-, -CO-, -N(R)- (wherein R represents a hydrogen atom or an alkyl group), -NHS0₂-, or a divalent linking group formed by combining a plurality of these groups.

Q represents an alicyclic structure. The alicyclic structure may have a substituent and may be monocyclic or polycyclic, and in the case of polycyclic, the structure may be crosslinked. The monocyclic structure is preferably a cycloalkyl group having a carbon number of 3 to 8, and examples thereof include a cyclopentyl group, a cyclohexyl group, a cyclobutyl group and a cyclooctyl group. Examples of the polycyclic structure include a group containing a bicyclo, tricyclo or tetracyclo structure having a carbon number of 5 or more. A cycloalkyl group having a carbon number of 6 to 20 is preferred, and examples thereof include an adamantyl group, a norbornyl group, a dicyclopentyl group, a tricyclodecanyl group and a tetracyclododecyl group. At least one of carbon atoms in the cycloalkyl group may be replaced by a heteroatom such as oxygen atom. In particular, Q is preferably, for example, a norbornyl group, a tricyclodecanyl group or a tetracyclododecyl group.

The hydrophobic resin may contain a silicon atom. A resin having an alkylsilyl structure (preferably a trialkylsilyl group) or a cyclic siloxane structure, as a silicon atom-containing partial structure, is preferred.

Specific examples of the alkylsilyl structure and cyclic siloxane structure include groups represented by the following formulae (CS-1) to (CS-3):

(CS-1 ) (CS-2) (CS-3)

In formulae (CS-1) to (CS-3), each of Ri₂ to R₂₆ independently represents a linear or branched alkyl group (preferably having a carbon number of 1 to 20) or a cycloalkyl group (preferably having a carbon number of 3 to 20).

Each of L₃ to L₅ represents a single bond or a divalent linking group. The divalent linking group is a sole group or a combination of two or more groups selected from the group consisting of an alkylene group, a phenylene group, an ether bond, a thioether bond, a carbonyl group, an ester bond, an amide bond, a urethane bond and a ureylene bond,

n represents an integer of 1 to 5. n is preferably an integer of 2 to 4.

The repeating unit having at least either a fluorine atom or a silicon atom is preferably a (meth)acrylate-based repeating unit.

Specific examples of the repeating unit having at least either a fluorine atom or a silicon atom are illustrated below, but the present invention is not limited thereto. In specific examples, Xi represents a hydrogen atom, -CH₃, -F or -CF₃, and X₂ represents -F or -CF3.

53

54

group selected from the group consisting of the following (x) to (z):

(x) an alkali-soluble group,

(y) a group capable of decomposing by the action of an alkali developer to increase the solubility for an alkali developer (hereinafter, sometimes referred to as a polarity converting group), and

(z) a group capable of decomposing by the action of an acid to increase the solubility for an alkali developer.

The repeating unit (b) includes the following types:

(b') a repeating unit having at least either a fluorine atom or a silicon atom and at least one group selected from the group consisting of (x) to (z), on one side chain,

(b*) a repeating unit having at least one group selected from the group consisting of (x) to (z) and at the same time, having neither a fluorine atom nor a silicon atom, and

(b") a repeating unit having at least one group selected from the group consisting of (x) to (z) above on one side chain and at the same time, having at least either a fluorine atom or a silicon atom on a side chain different from the side chain above in the same repeating unit.

The hydrophobic resin more preferably contains a repeating unit (b') as the repeating unit (b). In other words, it is more preferred that the repeating unit (b) having at least one group selected from the group consisting of (x) to (z) above has at least either a fluorine atom or a silicon atom.

In the case where the hydrophobic resin contains the repeating unit (b*), the resin is preferably a copolymer with a repeating unit having at least either a fluorine atom or a silicon atom (a repeating unit different from the repeating units (b') and (b") above). Also, in the repeating unit (b"), the side chain having at least one group selected from the group consisting of (x) to (z) and the side chain having at least either a fluorine atom or a silicon atom are preferably bonded to the same carbon atom in the main chain, that is, have a positional relationship as in the following formula (Kl).

In the formula, Bl represents a partial structure having at least one group selected from the group consisting of (x) to (z), and B2 represents a partial structure having at least either a fluorine atom or a silicon atom.

The group selected from the group consisting of (x) to (z) is preferably (x) an alkali-soluble group or (y) a polarity converting group, more preferably (y) a polarity converting group.

Examples of the alkali-soluble group (x) include a phenolic hydroxyl group, a carboxylic acid group, a fluorinated alcohol group, a sulfonic acid group, a sulfonamide group, a sulfonylimide group, an (alkylsulfonyl)(alkylcarbonyl)methylene group, an (alkylsulfonyl)(alkylcarbonyl)imide group, a bis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imide group, a bis(alkylsulfonyl)mefhylene group, a bis(alkylsulfonyl)imide group, a tris(alkylcarbonyl)methylene group, and a tris(alkylsulfonyl)methylene group.

Preferred alkali-soluble groups include a fluorinated alcohol group (preferably hexafluoroisopropanol), a sulfonimide group, and a bis(carbonyl)methylene group.

The repeating unit (bx) having (x) an alkali-soluble group includes a repeating unit where an alkali-soluble group is directly bonded to the main chain of the resin, such as repeating unit by an acrylic acid or a methacrylic acid; and a repeating unit where an alkali-soluble group is bonded to the main chain of the resin through a linking group. Furthermore, an alkali-soluble group may be introduced into the terminal of the polymer chain by using an alkali-soluble group-containing polymerization initiator or chain transfer agent at the polymerization. All of these cases are preferred.

In the case where the repeating unit (bx) is a repeating unit having at least either a fluorine atom or a silicon atom (that is, a repeating unit corresponding to the repeating unit (b') or (b")), examples of the fluorine atom-containing partial structure in the repeating unit (bx) are the same as those in the above-described repeating unit having at least either a fluorine atom or a silicon atom, and the groups represented by formula (F2) to (F4) are preferred. Also, examples of the silicon atom-containing partial structure in the repeating unit (bx) are the same as those in the above-described repeating unit having at least either a fluorine atom or a silicon atom, and the groups represented by formulae (CS-1) to (CS-3) are preferred.

The content of the repeating unit (bx) having (x) an alkali-soluble group is preferably from 1 to 50 mol%, more preferably from 3 to 35 mol%, still more preferably from 5 to 20 mol%, based on all repeating units in the hydrophobic resin.

Specific examples of the repeating unit (bx) having (x) an alkali-soluble group are illustrated below, but the present invention is not limited thereto. In specific examples, Xi represents a hydrogen atom, -CH₃, -F or -CF₃.

In formulae, Rx represents H, CH₃, CF₃ or CH₂OH.

Examples of the polarity converting group (y) include a lactone group, a carboxylic acid ester group (-COO-), an acid anhydride group (-C(O)OC(O)-), an acid imide group (-NHCONH-), a carboxylic acid thioester group (-COS-), a carbonic acid ester group (-OC(O)O-), a sulfuric acid ester group (-OS0₂0-), and a sulfonic acid ester group (-S0₂0-), with a lactone group being preferred.

As for the polarity converting group (y), both an embodiment where the group is contained, for example, in a repeating unit by an acrylic acid ester or a methacrylic acid ester and thereby is introduced into the side chain of the resin, and an embodiment where the group is introduced into the terminal of the polymer chain by using a polymerization initiator or chain transfer agent having (y) a polarity converting group, are preferred.

Specific examples of the repeating unit (by) having (y) a polarity converting group include repeating units having a lactone structure represented by formulae (KA-1- 1) to (KA-1-17) described later.

The repeating unit (by) having (y) a polarity converting group is preferably a repeating unit having at least either a fluorine atom or a silicon atom (that is, a repeating unit corresponding to the repeating unit (b') or (b")). The resin containing the repeating unit (by) has hydrophobicity, but this repeating unit is preferred particularly in view of reducing the development defect.

The repeating unit (by) includes, for example, a repeating unit represented by formula

In the formula, R_ki represents a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an aryl group, or a polarity converting group-containing group.

Ric2 represents an alkyl group, a cycloalkyl group, an aryl group, or a polarity converting group-containing group.

However, at least either one of Rki and Rk₂ represents a polarity converting group-containing group.

The polarity converting group is, as described above, a group capable of decomposing by the action of an alkali developer to increase the solubility in an alkali developer. The polarity converting group is preferably a group X in a partial structure represented by formula

In formulae (KA-1) and (KB-1), X represents a carboxylic acid ester group: -COO-, an acid anhydride group: -C(0)OC(0)-, an acid imide group: -NHCONH-, a carboxylic acid thioester group: -COS-, a carbonic acid ester group: -OC(0)0-, a sulfuric acid ester group: -OS0₂0-, or a sulfonic acid ester group: -S0₂0-.

Each of Y 1 and Y 2 , which may be the same or different, represents an electron-withdrawing group.

Incidentally, the repeating unit (by) has a preferred group capable of increasing the solubility in an alkali developer by containing a group having a partial structure represented by formula (KA-1) or (KB-1), but as in the case of the partial structure represented by formula (KA-1) or the partial structure represented by formula (KB-1) where Y¹ and Y² are monovalent, when the partial structure does not have a bond, the group having the partial structure is a group having a monovalent or higher valent group formed by removing at least one arbitrary hydrogen atom in the partial structure.

The partial structure represented by formula (KA-1) or (KB-1) is connected to the main chain of the hydrophobic resin at an arbitrary position through a substituent.

The partial structure represented by formula (KA-1) is a structure forming a ring structure together with the group as X.

In formula (KA- 1 ), X is preferably a carboxylic acid ester group (that is, a case of forming a lactone ring structure as KA-1), an acid anhydride group or a carbonic acid ester group, more preferably a carboxylic acid ester group.

The ring structure represented by formula (KA-1) may have a substituent and, for example, may have nka substituents Z_kai .

Z_kai represents, when a plurality of Ziyi's are present, each independently represents, a halogen atom, an alkyl group, a cycloalkyl group, an ether group, a hydroxyl group, an amide group, an aryl group, a lactone ring group or an electron-withdrawing group.

Zk_ai's may combine with each other to form a ring. Examples of the ring formed by combining Zkai's with each other include a cycloalkyl ring and a heterocyclic ring (e.g., cyclic ether ring, lactone ring).

nka represents an integer of 0 to 10 and is preferably an integer of 0 to 8, more preferably an integer of 0 to 5, still more preferably an integer of 1 to 4, and most preferably an integer of 1 to 3.

The electron-withdrawing group as Zkai has the same meaning as the electron- withdrawing group of Y¹ and Y² described later. The electron-withdrawing group above may be substituted with another electron-withdrawing group.

Zkai is preferably an alkyl group, a cycloalkyl group, an ether group, a hydroxyl group or an electron-withdrawing group, more preferably an alkyl group, a cycloalkyl group or an electron-withdrawing group. The ether group is preferably an ether group substituted, for example, with an alkyl group or a cycloalkyl group, that is, an alkyl ether group. The electron-withdrawing group has the same meaning as above.

Examples of the halogen atom as Zkai include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, with a fluorine atom being preferred.

The alkyl group as Zkai may have a substituent and may be either linear or branched. The linear alkyl group is preferably an alkyl group having a carbon number of 1 to 30, more preferably from 1 to 20, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group and an n-decanyl group. The branched alkyl group is preferably an alkyl group having a carbon number of 3 to 30, more preferably from 3 to 20, and examples thereof include an i-propyl group, an i-butyl group, a tert-butyl group, an i-pentyl group, a tert-pentyl group, an i-hexyl group, a tert-hexyl group, an i-heptyl group, a tert-heptyl group, an i-octyl group, a tert-octyl group, an i-nonyl group and a tert-decanoyl group. An alkyl group having a carbon number of 1 to 4, such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group and tert-butyl group, is preferred.

The cycloalkyl group as Z_kai may have a substituent and may be monocyclic or polycyclic, and in the case of polycyclic, the cycloalkyl group may be crosslinked. That is, in this case, the cycloalkyl group may have a bridged structure.

The monocyclic cycloalkyl group is preferably a cycloalkyl group having a carbon number of 3 to 8, and examples thereof include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclobutyl group and a cyclooctyl group.

Examples of the polycyclic cycloalkyl group include a group having a bicyclo, tricyclo or tetracyclo structure and having a carbon number of 5 or more. A cycloalkyl group having a carbon number of 6 to 20 is preferred, and examples thereof include an adamantyl group, a norbornyl group, an isoboronyl group, a camphanyl group, a dicyclopentyl group, an ct-pinel group, a tricyclodecanyl group, a tetracyclododecyl group and an androstanyl group.

As cycloalkyl groups, the following structures are also preferred. Incidentally, at least one of carbon atoms in the cycloalkyl group may be replaced by a heteroatom such as oxygen atom.

The alicyclic moiety is preferably an adamantyl group, a noradamantyl group, a decalin group, a tricyclodecanyl group, a tetracyclododecanyl group, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecanyl group or a cyclododecanyl group, more preferably an adamantyl group, a decalin group, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecanyl group, a cyclododecanyl group or a tricyclodecanyl group.

The substituent of the alicyclic structure includes an alkyl group, a halogen atom, a hydroxyl group, an alkoxy group, a carboxyl group and an alkoxycarbonyl group. The alkyl group is preferably a lower alkyl group such as methyl group, ethyl group, propyl group, isopropyl group and butyl group, more preferably a methyl group, an ethyl group, a propyl group or an isopropyl group. The alkoxy group is preferably an alkoxy group having a carbon number of 1 to 4, such as methoxy group, ethoxy group, propoxy group and butoxy group. Examples of the substituent which the alkyl group and alkoxy group may have include a hydroxyl group, a halogen atom and an alkoxy group (preferably having a carbon number of 1 to 4).

The groups above may further have a substituent, and examples of the further substituent include a hydroxyl group, a halogen atom (e.g., fluorine, chlorine, bromine, iodine), a nitro group, a cyano group, the above-described alkyl group, an alkoxy group such as methoxy group, ethoxy group, hydroxyethoxy group, propoxy group, hydroxypropoxy group, n-butoxy group, isobutoxy group, sec-butoxy group and tert-butoxy group, an alkoxycarbonyl group such as methoxycarbonyl group and ethoxycarbonyl group, an aralkyl group such as benzyl group, phenethyl group and cumyl group, an aralkyloxy group, an acyl group such as formyl group, acetyl group, butyryl group, benzoyl group, cianamyl group and valeryl group, an acyloxy group such as butyryloxy group, the alkenyl group such as a vinyl group, propenyl group and an allyl group, an alkenyloxy group such as vinyloxy group, propenyloxy group, allyloxy group and butenyloxy group, the aryl group such as a phenyl group and a naphtyl group, an aryloxy group such as phenoxy group, and an aryloxycarbonyl group such as benzoyloxy group.

It is preferred that X in formula (KA-1) is a carboxylic acid ester group and the partial structure represented by formula (KA-1) is a lactone ring, and the lactone ring is preferably a 5- to 7-membered lactone ring.

In this connection, as in (KA-1-1) to (KA-1 -17) shown below, another ring structure is preferably fused to a 5- to 7-membered lactone ring that is the partial structure represented by formula (KA-1), in the form of forming a bicyclo or spiro structure.

Examples of the peripheral ring structure with which the ring structure represented by formula (KA-1) may combine include those in (KA-1-1) to (KA-1-17) shown below and structures based on these structures.

The structure containing the lactone ring structure represented by formula (KA-1) is more preferably a structure represented by any one of the following (KA-1-1) to (KA-1-17). The lactone structure may be bonded directly to the main chain. Preferred structures are KA-1-1), ( ), ( -1-5 (KA-1-6), (KA-1-13), (KA-1-14) and (KA-1-17).

The structure containing the above-described lactone ring structure may or may not have a substituent. Preferred examples of the substituent are the same as those of the substituent Zkai which the ring structure represented by formula (KA-1) may have.

In formula (KB-1), X is preferably a carboxylic acid ester group (-COO-).

In formula (KB-1), each of Y¹ and Y² independently represents an electron- withdrawing group.

The electron-withdrawing group is a partial structure represented by the following formula (EW). In formula (EW), * indicates a bond directly bonded to (KA-1) or a bond directly bonded to X in (KB-1).

In formula (EW), each of R_ewi and R_ew2 independently represents an arbitrary substituent, for example, represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group.

n_ew is a repetition number of the linking group represented by -C(R_ewi)(Rew2)- and represents an integer of 0 or 1. In the case where n_ew is 0, this indicates that the bond is a single bond and Y_ewi is directly bonded.

Yewi is a halogen atom, a cyano group, a nitrile group, a nitro group, a halo(cyclo)alkyl or haloaryl group represented by -C(Rn)(Rf2)-Ro described later, an oxy group, a carbonyl group, a sulfonyl group, a sulfinyl group, or a combination thereof. The electron-withdrawing group may be, for example, a structure shown below. The term "halo(cyclo)alkyl group" indicates an alkyl or cycloalkyl group that is at least partially halogenated, and the "haloaryl group" indicates an aryl group that is at least partially halogenated. In the following structural formulae, each of R_ew3 and R_ew4 independently represents an arbitrary structure. The partial structure represented by formula (EW) has an electron-withdrawing group regardless of what structure e_w3 or R_ew4 may take, and each of Re_w3 and R_eW4 may be connected, for example, to the main chain of the resin but is preferably an alkyl group, a cycloalkyl group or an alkyl fluoride group.

In the case where Y_ewi is a divalent or higher valent group, the remaining bond forms bonding to an arbitrary atom or substituent. At least any one group of Y_ewi , R_ewi and R_ew2 may be connected to the main chain of the hydrophobic resin through a further substituent.

Yewi is preferably a halogen atom or a halo(cyclo)alkyl or haloaryl group represented by -C(Rn)(Rf2)-Ro.

At least two members out of R_ewi , _eW2 and Y_ewi may combine with each other to form a ring.

Rn represents a halogen atom, a perhaloalkyl group, a perhalocycloalkyl group or a perhaloaryl group and is preferably a fluorine atom, a perfluoroalkyl group or a perfluorocycloalkyl group, more preferably a fluorine atom or a trifluoromethyl group.

Each of Rf2 and Ro independently represents a hydrogen atom, a halogen atom or an organic group, and Rn and Ro may combine to form a ring. Examples of the organic group include an alkyl group, a cycloalkyl group and an alkoxy group. Rf2 is preferably the same group as R_n or combines with Rf3 to form a ring.

Rn to Ro may combine to form a ring, and examples of the ring formed include a (halo)cycloalkyl ring and a (halo)aryl ring.

Examples of the (halo)alkyl group in Rn to R include the alkyl groups in Zkai described above and halogenated structures thereof.

Examples of the (per)halocycloalkyl group and (per)haloaryl group in Rn to Rf3 or in the ring formed by combining Rf2 and Ro include a structure formed by halogenation of the cycloalkyl group in Zkai described above, preferably a fluorocycloalkyl group represented by -C_(n)F(2n-2)H, and a perfluoroaryl group represented by -C_(n)F(_n-1), wherein the carbon number n is not particularly limited but is preferably from 5 to 13, more preferably 6.

The ring which may be formed by combining at least two members of R_ewi, R_ew2 and Yewi with each other is preferably a cycloalkyl group or a heterocyclic group, and the heterocyclic group is preferably a lactone ring group. Examples of the lactone ring include structures represented by formulae (KA-1-1) to (KA-1- 17).

Incidentally, the repeating unit (by) may have a plurality of partial structures represented by formula (KA-1), a plurality of partial structures represented by formula (KB-1), or both a partial structure of formula (KA-1) and a partial structure of formula (KB-1).

In this connection, the partial structure of formula (KA-1) may partially or entirely serve also as the electron-withdrawing group of Y¹ or Y² in formula (KB-1). For example, in the case where X in formula (KA-1) is a carboxylic acid ester group, the carboxylic acid ester group may function as an electron-withdrawing group of Y or Y in formula (KB-1).

Also, in the case where the repeating unit (by) comes under the repeating unit (b*) or the repeating unit (b") and has a partial structure represented by formula (KA-1), the partial structure represented by formula (KA-1) is more preferably a partial structure where the polarity converting group is -COO- in the structure represented by formula (KA-1).

The repeating unit (by) may be a repeating unit having a partial structure represented by formula (KY-0):

In formula (KY-0), R₂ represents a chain or cyclic alkylene group and when a plurality of R₂'s are present, these may be the same or different.

R₃ represents a linear, branched or cyclic hydrocarbon group where a part or all of hydrogen atoms on the constituent carbons are replaced by a fluorine atom.

R4 represents a halogen atom, a cyano group, a hydroxy group, an amide group, an alkyl group, a cycloalkyl group, an alkoxy group, a phenyl group, an acyl group, an alkoxycarbonyl group or a group represented by R-C(=0)- or R-C(=0)0- (wherein R represents an alkyl group or a cycloalkyl group). When a plurality of Rt's are present, these may be the same or different, and two or more R₄ S may combine to form a ring.

X represents an alkylene group, an oxygen atom or a sulfur atom.

Each of Z and Za represents a single bond, an ether bond, an ester bond, an amide bond, a urethane bond or a urea bond and when a plurality of Z's or Za's are present, each Z or Za may be the same as or different from each other Z or Za.

* represents a bond to the main or side chain of the resin.

o is the number of substituents and represents an integer of 1 to 7.

m is the number of substituents and represents an integer of 0 to 7.

n is a repetition number and represents an integer of 0 to 5.

The structure of -R₂-Z- is preferably a structure represented by -(CH₂)i-COO- (wherein 1 represents an integer of 1 to 5).

The preferred carbon number range and specific examples of the chain or cyclic alkylene group as R₂ are the same as those described for the chain alkylene group and cyclic alkylene group in Z₂ of formula (bb).

The carbon number of the linear, branched or cyclic hydrocarbon group as R₃ is, in the case of a linear hydrocarbon group, preferably from 1 to 30, more preferably from 1 to 20; in the case of a branched hydrocarbon group, preferably from 3 to 30, more preferably from 3 to 20; and in the case of a cyclic hydrocarbon group, from 6 to 20. Specific examples of R₃ include specific examples of the alkyl group and cycloalkyl group as Zk_ai above.

The preferred carbon numbers and specific examples of the alkyl group and cycloalkyl group as R₄ and R are the same as those described above for the alkyl group and cycloalkyl group as .

The acyl group as R₄ is preferably an acyl group having a carbon number of 1 to 6, and examples thereof include a formyl group, an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a valeryl group and a pivaloyl group.

The alkyl moiety in the alkoxy group and alkoxycarbonyl group as R₄ includes a linear, branched or cyclic alkyl moiety, and the preferred carbon number and specific examples of the alkyl moiety are the same as those described above for the alkyl group and cycloalkyl group as Z_kai.

The alkylene group as X includes a chain or cyclic alkylene group, and the preferred carbon number and specific examples thereof are the same as those described for the chain alkylene group and cyclic alkylene group as R₂.

As for the specific structure of the repeating unit (by), the repeating unit also includes repeating units having a partial structure shown below.

*— X'-A-O-C— X -X'-A-C-O-X

I I II

O (rf-1) O (rf-2)

In formulae (rf-1) and (rf-2), X' represents an electron- withdrawing substituent and is preferably a carbonyloxy group, an oxycarbonyl group, a fluorine atom-substituted alkylene group or a fluorine atom-substituted cycloalkylene group.

A represents a single bond or a divalent linking group represented by -C(Rx)(Ry)-, wherein each of Rx and Ry independently represents a hydrogen atom, a fluorine atom, an alkyl group (preferably having a carbon number of 1 to 6; which may be substituted with a fluorine atom or the like), or a cycloalkyl group (preferably having a carbon number of 5 to 12; which may be substituted with a fluorine atom or the like). Each of Rx and Ry is preferably a hydrogen atom, an alkyl group or a fluorine atom-substituted alkyl group.

X represents an electron-withdrawing group and specific examples thereof include those electron- withdrawing groups as Y¹ and Y² above. Among these, an alkyl fluoride group, a cycloalkyl fluoride group, an aryl group substituted with fluorine or an alkyl fluoride group, an aralkyl group substituted with fluorine or an alkyl fluoride group, a cyano group and a nitro group are preferred.

* represents a bond to the main or side chain of the resin, that is, a bond which is bonded to the main chain of the resin through a single bond or a linking group.

Incidentally, when X' is a carbonyloxy group or an oxycarbonyl group, A is not a single bond.

The polarity converting group is decomposed by the action of an alkali developer to effect polarity conversion, whereby the receding contact angle with water of the resist film after alkali development can be decreased. Decrease in the receding contact angle with water of the film after alkali development is preferred from the standpoint of suppressing the development defect.

The receding contact angle with water of the resist film after alkali development is preferably 50° or less, more preferably 40° or less, still more preferably 35° or less, and most preferably 30° or less, at a temperature of 23±3°C and a humidity of 45±5%.

The receding contact angle is a contact angle measured when a contact line recedes on the liquid droplet-substrate interface, and this is generally known to be useful in simulating the mobility of a liquid droplet in the dynamic state. In a simple manner, the receding contact angle can be defined as a contact angle at the time of the liquid droplet interface receding when a liquid droplet ejected from a needle tip is landed on a substrate and then the liquid droplet is again suctioned into the needle. In general, the receding contact angle can be measured by a contact angle measuring method called an expansion/contraction method.

The hydrolysis rate of the hydrophobic resin for an alkali developer is preferably 0.001 nm/sec or more, more preferably 0.01 nm/sec or more, still more preferably 0.1 nm/sec or more, and most preferably 1 nm/sec or more.

The hydrolysis rate of the hydrophobic resin for an alkali developer is the rate at which the thickness of a resin film formed of only the hydrophobic resin decreases when treated with TMAH (an aqueous tetramethyl ammonium hydroxide solution) (2.38 mass%) at 23°C.

The repeating unit (by) is more preferably a repeating having at least two or more polarity converting groups.

In the case where the repeating unit (by) has at least two polarity converting groups, the repeating unit preferably has a group containing a partial structure having two polarity converting groups represented by the following formula (KY-1). Incidentally, when the structure represented by formula (KY-1 ) does not have a bond, this is a group containing a monovalent or greater valent group formed by removing at least one arbitrary hydrogen atom from the structure.

In formula (KY-1), each of Rk_yi and Rk_y4 independently represents a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, a carbonyl group, a carbonyloxy group, an oxycarbonyl group, an ether group, a hydroxyl group, a cyano group, an amide group or an aryl group. Alternatively, Rk_yi and Rk_y4 may be bonded to the same atom to form a double bond. For example, Rkyi and Rk_y4 may be bonded to the same oxygen atom to form a part (=0) of a carbonyl group.

Each of Rk_y2 and Rk_y3 independently represents an electron-withdrawing group, or while Rkyi and Rk_y2 combine to form a lactone ring, Rk_y3 is an electron-withdrawing group. The lactone ring formed is preferably a structure of (KA-1-1) to (KA-1-17). Examples of the electron-withdrawing group is the same as those for Y¹ and Y² in formula (KB-1), and a halogen atom and a halo(cyclo)alkyl or haloaryl group represented by -C(Rn)(Rf2)-RD described above are preferred. Preferably, Rk_y3 is a halogen atom or a halo(cyclo)alkyl or haloaryl group represented by -C(Rfi)(Rf2)-Ro, and Rk_y2 combines with Rk_yi to form a lactone ring or is an electron-withdrawing group containing no halogen atom.

R-kyb Rky2 and Rk_y4 may combine with each other to form a monocyclic or polycyclic structure.

Specific examples of Rk_yi and Rk_y4 include the same groups as those for Zk_ai in formula (KA-1).

The lactone ring formed by combining Rk_yi and Rk_y2 is preferably a structure of (KA-1-1) to (KA-1-17). Examples of the electron- withdrawing group are the same as those for Y¹ and Y² in formula (KB-1).

The structure represented by formula (KY-1) is preferably a structure represented by the following formula (KY-2). Here, the structure represented by formula (KY-2) is a group having a monovalent or higher valent group formed by removing at least one arbitrary hydrogen atom from the structure.

In formula (KY-2), each of Rk_y6 to Rkyio independently represents a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, a carbonyl group, a carbonyloxy group, an oxycarbonyl group, an ether group, a hydroxyl group, a cyano group, an amide group or an aryl group.

Two or more members of Rk_y6 to Rkyio may combine with each other to form a monocyclic or polycyclic structure.

Rk_y5 represents an electron-withdrawing group. Examples of the electron-withdrawing group are the same as those for Y¹ and Y² above, and a halogen atom and a halo(cyclo)alkyl or haloaryl group represented by -C(Rfi )(Ra)-Ro are preferred.

Specific examples of Rk_y5 to Rkyio include the same groups as those for Zkai in formula (KA-1).

The structure represented by formula (KY-2) is preferably a partial structure represented by the following formula (KY-3):

In formula (KY-3), Zkai and nka have the same meanings as in formula (KA-1). Rk_y5 has the same meaning as in formula (KY-2).

Lky represents an alkylene group, an oxygen atom or a sulfur atom. Examples of the alkylene group of Lk_y include a methylene group and an ethylene group. Lk_y is preferably an oxygen atom or a methylene group, more preferably a methylene group.

The repeating unit (b) is not limited as long as it is a repeating unit obtained by polymerization such as addition polymerization, condensation polymerization and addition condensation, but this repeating unit is preferably a repeating unit obtained by addition polymerization of a carbon-carbon double bond. Examples thereof include an acrylate-based repeating unit (including a system having a substituent at the a- or β-position), a styrene-based repeating unit (including a system having a substituent at the a- or β-position), a vinyl ether-based repeating unit, a norbornene-based repeating unit, and a maleic acid derivative (such as maleic anhydride, its derivative, and maleimide) repeating unit. An acrylate-based repeating unit, a styrene-based repeating unit, a vinyl ether-based repeating unit and a norbornene-based repeating unit are preferred, an acrylate-based repeating unit, a vinyl ether-based repeating unit and a norbornene-based repeating unit are more preferred, and an acrylate-based repeating unit is most preferred.

In the case where the repeating unit (by) is a repeating unit having at least either a fluorine atom or a silicon atom (that is, a repeating unit corresponding to the repeating unit (b') or (b")), examples of the fluorine atom-containing partial structure in the repeating unit (by) are the same as those in the repeating unit having at least either a fluorine atom or a silicon atom described above, and the groups represented by formula (F2) to (F4) described above are preferred. Also, examples of the silicon atom-containing partial structure in the repeating unit (by) are the same as those in the repeating unit having at least either a fluorine atom or a silicon atom described above, and the groups represented by formulae (CS-1) to (CS-3) described above are preferred.

In the hydrophobic resin, the content of the repeating unit (by) is preferably from 10 to 100 mol%, more preferably from 20 to 99 mol%, still more preferably from 30 to 97 mol%, and most preferably from 40 to 95 mol%, based on all repeating units in the hydrophobic resin.

Specific examples of the repeating unit (by) having a group capable of increasing the solubility in an alkali developer are illustrated below, but the present invention is not limited thereto. Specific examples of the repeating unit (by) also include those described as specific examples of the repeating unit (a3) of the resin (B).

In specific examples, a represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

As for the synthesis method of a monomer corresponding to the repeating unit (by) having (y) a polarity converting group, the monomer can be synthesized by referring to the method described, for example, in International Publication Nos. 2010/067905 and 2010/067905.

Examples of the repeating unit (bz) having (z) a group capable of decomposing by the action of an acid in the hydrophobic resin are the same as those of the repeating unit having an acid-decomposable group in the resin (B).

In the case where the repeating unit (bz) is a repeating unit having at least either a fluorine atom or a silicon atom (that is, a repeating unit corresponding to the repeating unit (b¹) or (b")), examples of the fluorine atom-containing partial structure in the repeating unit (bz) are the same as those in the above-described repeating unit having at least either a fluorine atom or a silicon atom, and the groups represented by formula (F2) to (F4) are preferred. Also, examples of the silicon atom-containing partial structure in the repeating unit (by) are the same as those in the above-described repeating unit having at least either a fluorine atom or a silicon atom, and the groups represented by formulae (CS-1) to (CS-3) are preferred.

In the hydrophobic resin, the content of the repeating unit (bz) having (z) a group capable of decomposing by the action of an acid is preferably from 1 to 80 mol%, more preferably from 10 to 80 mol%, still more preferably from 20 to 60 mol%, based on all repeating units in the hydrophobic resin.

While the repeating unit (b) having at least one group selected from the group consisting of (x) to (z) is described above, the content of the repeating unit (b) in the hydrophobic resin is preferably from 1 to 98 mol%, more preferably from 3 to 98 mol%, still more preferably from 5 to 97 mol%, and most preferably from 10 to 95 mol%, based on all repeating units in the hydrophobic resin.

The content of the repeating unit (b') is preferably from 1 to 100 mol%, more preferably from 3 to 99 mol%, still more preferably from 5 to 97 mol%, and most preferably from 10 to 95 mol%, based on all repeating units in the hydrophobic resin.

The content of the repeating unit (b*) is preferably from 1 to 90 mol%, more preferably from 3 to 80 mol%, still more preferably from 5 to 70 mol%, and most preferably from 10 to 60 mol%, based on all repeating units in the hydrophobic resin. The content of the repeating unit having at least either a fluorine atom or a silicon atom, which is used together with the repeating unit (b*), is preferably from 10 to 99 mol%, more preferably from 20 to 97 mol%, still more preferably from 30 to 95 mol%, and most preferably from 40 to 90 mol%, based on all repeating units in the hydrophobic resin.

The content of the repeating unit (b") is preferably from 1 to 100 mol%, more preferably from 3 to 99 mol%, still more preferably from 5 to 97 mol%, and most preferably from 10 to 95 mol%, based on all repeating units in the hydrophobic resin.

The hydrophobic resin may further contain a repeating unit represented by the following formula (CIII):

In formula (CIII), R^i represents a hydrogen atom, an alkyl group (which may be substituted with a fluorine atom and the like), a cyano group or a -CH2-0-R_ac2 group, wherein R_ac2 represents a hydrogen atom, an alkyl group or an acyl group. Rc₃i is preferably a hydrogen atom, a methyl group, a hydroxymethyl group or a trifluoromethyl group, more preferably a hydrogen atom or a methyl group.

Rc₃₂ represents a group having an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group or an aryl group. Each of these groups may be substituted with a fluorine atom- or silicon atom-containing group and the like.

Lc3 represents a single bond or a divalent linking group.

In formula (CIII), the alkyl group of Rc₃₂ is preferably a linear or branched alkyl group having a carbon number of 3 to 20.

The cycloalkyl group is preferably a cycloalkyl group having a carbon number of 3 to

20.

The alkenyl group is preferably an alkenyl group having a carbon number of 3 to 20. The cycloalkenyl group is preferably a cycloalkenyl group having a carbon number of

3 to 20.

The aryl group is preferably an aryl group having a carbon number of 6 to 20, more preferably a phenyl group or a naphthyl group, and each of these groups may have a substituent.

Rc₃₂ is preferably an unsubstituted alkyl group or a fluorine atom-substituted alkyl group.

The divalent linking group of L_c3 is preferably an alkylene group (preferably having a carbon number of 1 to 5), an oxy group, a phenylene group or an ester bond (a group represented by -C00-).

It is also preferable that the hydrophobic resin further contains a repeating unit represented by the following formula (BII-AB):

(BII-AB)

In formula (BII-AB), each of R_en' and R_d2' independently represents a hydrogen atom, a cyano group, a halogen atom or an alkyl group.

Z_c' represents an atomic group for forming an alicyclic structure containing two carbon atoms (C-C) to which Z_c' is bonded.

In the case where each group in the repeating units represented by formulae (III) and (BII-AB) is substituted with a fluorine atom- or silicon atom-containing group, the repeating unit corresponds also to the repeating unit having at least either a fluorine atom or a silicon atom described above.

Specific examples of the repeating units represented by formulae (III) and (BII-AB) are illustrated below, but the present invention is not limited thereto. In the formulae, Ra represents H, CH₃, CH₂OH, CF₃ or CN. Incidentally, the repeating unit where Ra is CF₃ corresponds also to the repeating unit having at least either a fluorine atom or a silicon atom described above.

In the hydrophobic resin, similarly to the resin (B) described above, it is of course preferred that the content of impurities such as metal is small, but also, the content of residual monomers or oligomer components is preferably from 0 to 10 mass%, more preferably from 0 to 5 mass%, still more preferably from 0 to 1 mass%. When these conditions are satisfied, a resist composition free from extraneous substances in the liquid or change with aging of sensitivity or the like can be obtained. Furthermore, in view of resolution, resist profile, side wall of resist pattern, roughness and the like, the molecular weight distribution (Mw/Mn, sometimes referred to as "dispersity") is preferably from 1 to 3, more preferably from 1 to 2, still more preferably from 1 to 1.8, most preferably from 1 to 1.5.

As for the hydrophobic resin, various commercially available products may be used, or the resin may be synthesized by a conventional method (for example, radical polymerization). Examples of the general synthesis method include a batch polymerization method of dissolving monomer species and an initiator in a solvent and heating the solution, thereby effecting the polymerization, and a dropping polymerization method of adding dropwise a solution containing monomer species and an initiator to a heated solvent over 1 to 10 hours. A dropping polymerization method is preferred.

The reaction solvent, the polymerization initiator, the reaction conditions (e.g., temperature, concentration) and the purification method after reaction are the same as those described for the resin (B).

Specific examples of the hydrophobic resin (HR) are illustrated below. Also, the molar ratio of repeating units (corresponding to repeating units starting from the left), weight average molecular weight and dispersity of each resin are shown in Table 1 later.

(B-40) (B-41) (B_^2)

Table 1

Compositional

Polymer Mw Mw/Mn

Ratio (mol%)

B-l 50/50 6000 1.5

B-2 30/70 6500 1.4

B-3 45/55 8000 1.4

B-4 100 15000 1.7

B-5 60/40 6000 1.4

B-6 40/60 8000 1.4

B-7 30/40/30 8000 1.4

B-8 60/40 8000 1.3

B-9 50/50 6000 1.4

B-10 40/40/20 7000 1.4

B-l l 40/30/30 9000 1.6

B-12 30/30/40 6000 1.4

B-13 60/40 9500 1.4

B-14 60/40 8000 1.4

B-15 35/35/30 7000 1.4

B-16 50/40/5/5 6800 1.3

B-17 20/30/50 8000 1.4

B-18 25/25/50 6000 1.4

B-19 100 9500 1.5

B-20 100 7000 1.5

B-21 50/50 6000 1.6

B-22 40/60 9600 1.3

B-23 100 20000 1.7

B-24 100 25000 1.4

B-25 100 15000 1.7

B-26 100 12000 1.8

B-27 100 18000 1.3

B-28 70/30 15000 2.0 The actinic ray-sensitive or radiation-sensitive resin composition of the present invention contains a hydrophobic resin containing at least either a fluorine atom or a silicon atom, and the hydrophobic resin is unevenly distributed to the surface layer of a film formed of the actinic ray-sensitive or radiation-sensitive resin composition, so that when the immersion medium is water, the receding contact angle for water on the film surface after baking but before exposure as well as the followability of the immersion liquid can be enhanced.

The receding contact angle of a film after baking a coating composed of the actinic ray-sensitive or radiation-sensitive resin composition of the present invention but before exposure is preferably from 60 to 90°, more preferably 65° or more, still more preferably 70° or more, yet still more preferably 75° or more, at the temperature during exposure, usually room temperature 23±3°C, and a humidity of 45±5%.

The hydrophobic resin is, as described above, unevenly distributed to the interface but unlike a surfactant, need not have necessarily a hydrophilic group in the molecule and may not contribute to uniform mixing of polar/nonpolar substances.

In the immersion exposure step, the immersion liquid must move on a wafer following the movement of an exposure head that is scanning the wafer at a high speed and forming an exposure pattern. Therefore, the contact angle of the immersion liquid with the resist film in a dynamic state is important, and the resist is required to have a performance of allowing a liquid droplet to follow the high-speed scanning of an exposure head with no remaining.

The hydrophobic resin is hydrophobic and therefore, liable to worsen the development residue (scum) and BLOB defect after alkali development, but by virtue of having three or more polymer chains through at least one branch part, the alkali dissolution rate is enhanced as compared with a linear chain-type resin and in turn, the performance in terms of development residue (scum) and the BLO defect is improved.

In the case where the hydrophobic resin contains a fluorine atom, the fluorine atom content is preferably from 5 to 80 mass%, more preferably from 10 to 80 mass%, based on the molecular weight of the hydrophobic resin. Also, the fluorine atom-containing repeating unit preferably accounts for 10 to 100 mol%, more preferably from 30 to 100 mol%, based on all repeating units in the hydrophobic resin.

In the case where the hydrophobic resin contains a silicon atom, the silicon atom content is preferably from 2 to 50 mass%, more preferably from 2 to 30 mass%, based on the molecular weight of the hydrophobic resin. Also, the silicon atom-containing repeating unit preferably accounts for 10 to 90 mol%, more preferably from 20 to 80 mol%, based on all repeating units in the hydrophobic resin.

The weight average molecular weight of the hydrophobic resin is preferably from 1,000 to 100,000, more preferably from 2,000 to 50,000, still more preferably from 3,000 to 35,000. Here, the weight average molecular weight of the resin indicates a molecular weight in terms of polystyrene measured by GPC (carrier: tetrahydrofuran (THF)).

The hydrophobic resin may be used by appropriately adjusting its content in the actinic ray-sensitive or radiation-sensitive resin composition to give an actinic ray-sensitive or radiation-sensitive resin film having a receding contact angle in the range above, but the content thereof is preferably from 0.01 to 20 mass%, more preferably from 0.1 to 15 mass%, still more preferably from 0.1 to 10 mass%, yet still more preferably from 0.5 to 8 mass%, based on the entire solid content of the actinic ray-sensitive or radiation-sensitive resin composition.

As for the hydrophobic resin, one kind may be used alone, or two or more kinds may be used in combination.

[4] Basic compound

The actinic ray-sensitive or radiation-sensitive resin composition of the present invention preferably contains a basic compound so as to reduce the change in performance with aging from exposure to heating.

Preferred basic compounds include a basic compound having a structure represented by the following formulae (A) to (E):

In formulae (A) to (E), each of R²⁰⁰, R²⁰¹ and R²⁰², which may be the same or different, represents a hydrogen atom, an alkyl group (preferably having a carbon number of 1 to 20), a cycloalkyl group (preferably having a carbon number of 3 to 20) or an aryl group (having a carbon number of 6 to 20), and R²⁰¹ and R²⁰² may combine together to form a ring.

Each of R²⁰³, R²⁰⁴, R²⁰⁵ and R²⁰⁶, which may be the same or different, represents an alkyl group having a carbon number of 1 to 20.

As for the alkyl group, the alkyl group having a substituent is preferably an aminoalkyl group having a carbon number of 1 to 20, a hydroxyalkyl group having a carbon number of 1 to 20, or a cyanoalkyl group having a carbon number of 1 to 20.

The alkyl group in formulae (A) to (E) is more preferably unsubstituted.

Preferred examples of the compound include guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine and piperidine. More preferred examples of the compound include a compound having an imidazole structure, a diazabicyclo structure, an onium hydroxide structure, an onium carboxylate structure, a tnalkylamine structure, an aniline structure or a pyridine structure; an alkylamine derivative having a hydroxyl group and/or an ether bond; and an aniline derivative having a hydroxyl group and/or an ether bond.

Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, benzimidazole and 2-phenylbenzimidazole. Examples of the compound having a diazabicyclo structure include l,4-diazabicyclo[2,2,2]octane, l,5-diazabicyclo[4,3,0]non-5-ene and l,8-diazabicyclo[5,4,0]undeca-7-ene. Examples of the compound having an onium hydroxide structure include a tetrabutylammonium hydroxide, a triarylsulfonium hydroxide, a phenacylsulfonium hydroxide and a sulfonium hydroxide having a 2-oxoalkyl group, specifically, triphenylsulfonium hydroxide, tris(tert-butylphenyl)sulfonium hydroxide, bis(tert-butylphenyl)iodonium hydroxide, phenacylthiophenium hydroxide and 2-oxopropylthiophenium hydroxide. The compound having an onium carboxylate structure is a compound where the anion moiety of the compound having an onium hydroxide structure becomes a carboxylate, and examples thereof include an acetate, an adamantane-1 -carboxylate and a perfluoroalkyl carboxylate. Examples of the compound having a trialkylamine structure include tri(n-butyl)amine and tri(n-octyl)amine. Examples of the aniline compound include 2,6-diisopropylaniline, N,N-dimethylaniline, Ν,Ν-dibutylaniline and N,N-dihexylaniline. Examples of the alkylamine derivative having a hydroxyl group and/or an ether bond include ethanolamine, diethanolamine, triethanolamine, N-phenyldiethanolamine and tris(methoxyethoxyethyl)amine. Examples of the aniline derivative having a hydroxyl group and/or an ether bond include N,N-bis(hydroxyethyl)aniline.

Other preferred basic compounds include a phenoxy group-containing amine compound, a phenoxy group-containing ammonium salt compound, a sulfonic acid ester group-containing amine compound and a sulfonic acid ester group-containing ammonium salt compound.

As for the amine compound, a primary, secondary or tertiary amine compound can be used, and an amine compound where at least one alkyl group is bonded to the nitrogen atom is preferred. The amine compound is more preferably a tertiary amine compound. In the amine compound, as long as at least one alkyl group (preferably having a carbon number of 1 to 20) is bonded to the nitrogen atom, a cycloalkyl group (preferably having a carbon number of 3 to 20) or an aryl group (preferably having a carbon number of 6 to 12) may be bonded to the nitrogen atom in addition to the alkyl group. The amine compound preferably has an oxygen atom in the alkyl chain to form an oxyalkylene group. The number of oxyalkylene groups within the molecule is 1 or more, preferably from 3 to 9, more preferably from 4 to 6. Among oxyalkylene groups, an oxyethylene group (-CH₂CH₂0-) and an oxypropylene group (-CH(CH₃)CH₂0- or -CH₂CH₂CH₂0-) are preferred, and an oxyethylene group is more preferred.

As for the ammonium salt compound, a primary, secondary, tertiary or quaternary ammonium salt compound can be used, and an ammonium salt compound where at least one alkyl group is bonded to the nitrogen atom is preferred. In the ammonium salt compound, as long as at least one alkyl group (preferably having a carbon number of 1 to 20) is bonded to the nitrogen atom, a cycloalkyl group (preferably having a carbon number of 3 to 20) or an aryl group (preferably having a carbon number of 6 to 12) may be bonded to the nitrogen atom in addition to the alkyl group. The ammonium salt compound preferably has an oxygen atom in the alkyl chain to form an oxyalkylene group. The number of oxyalkylene groups within the molecule is 1 or more, preferably from 3 to 9, more preferably from 4 to 6. Among oxyalkylene groups, an oxyethylene group (-CH₂CH₂0-) and an oxypropylene group (-CH(CH₃)CH₂0- or -CH₂CH₂CH₂0-) are preferred, and an oxyethylene group is more preferred.

Examples of the anion of the ammonium salt compound include a halogen atom, a sulfonate, a borate and a phosphate, with a halogen atom and a sulfonate being preferred. The halogen atom is preferably chloride, bromide or iodide, and the sulfonate is preferably an organic sulfonate having a carbon number of 1 to 20. Examples of the organic sulfonate include an alkylsulfonate having a carbon number of 1 to 20 and an arylsulfonate. The alkyl group of the alkylsulfonate may have a substituent, and examples of the substituent include fluorine, chlorine, bromine, an alkoxy group, an acyl group and an aryl group. Specific examples of the alkylsulfonate include methanesulfonate, ethanesulfonate, butanesulfonate, hexanesulfonate, octanesulfonate, benzylsulfonate, trifluoromethanesulfonate, pentafluoroethanesulfonate and nonafluorobutanesulfonate. The aryl group of the arylsulfonate includes a benzene ring, a naphthalene ring and an anthracene ring. The benzene ring, naphthalene ring and anthracene ring may have a substituent, and the substituent is preferably a linear or branched alkyl group having a carbon number of 1 to 6, or a cycloalkyi group having a carbon number of 3 to 6. Specific examples of the linear or branched alkyl group and cycloalkyi group include methyl, ethyl, n-propyl, isopropyl, n-butyl,

1- butyl, tert-butyl, n-hexyl and cyclohexyl. Other examples of the substituent include an alkoxy group having a carbon number of 1 to 6, a halogen atom, cyano, nitro, an acyl group and an acyloxy group.

The phenoxy group-containing amine compound and the phenoxy group-containing ammonium salt compound are an amine compound or ammonium salt compound having a phenoxy group at the terminal opposite the nitrogen atom of the alkyl group. The phenoxy group may have a substituent. Examples of the substituent of the phenoxy group include an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group, a carboxyl group, a carboxylic acid ester group, a sulfonic acid ester group, an aryl group, an aralkyl group, an acyloxy group and an aryloxy group. The substitution site of the substituent may be any of

2- to 6-positions, and the number of substituents may be any in the range of 1 to 5.

The compound preferably has at least one oxyalkylene group between the phenoxy group and the nitrogen atom. The number of oxyalkylene groups within the molecule is 1 or more, preferably from 3 to 9, more preferably from 4 to 6. Among oxyalkylene groups, an oxyethylene group (-CH₂CH₂0-) and an oxypropylene group (-CH(CH₃)CH₂0- or -CH₂CH₂CH₂0-) are preferred, and an oxyethylene group is more preferred.

The sulfonic acid ester group in the amine compound having a sulfonic acid ester group and the ammonium salt compound having a sulfonic acid ester group may be any of an alkylsulfonic acid ester, a cycloalkylsulfonic acid ester and an arylsulfonic acid ester. In the case of an alkylsulfonic acid ester, an alkyl group having a carbon number of 1 to 20 is preferred; in the case of a cycloalkylsulfonic acid ester, a cycloalkyi group having a carbon number of 3 to 20 is preferred; and in the case of an arylsulfonic acid ester, an aryl group having a carbon number of 6 to 12 is preferred. The alkylsulfonic acid ester, cycloalkylsulfonic acid ester and arylsulfonic acid ester may have a substituent, and the substituent is preferably a halogen atom, a cyano group, a nitro group, a carboxyl group, a carboxylic acid ester group or a sulfonic acid ester group.

The compound preferably has at least one oxyalkylene group between the sulfonic acid ester group and the nitrogen atom. The number of oxyalkylene groups within the molecule is 1 or more, preferably from 3 to 9, more preferably from 4 to 6. Among oxyalkylene groups, an oxyethylene group (-CH₂CH₂0-) and an oxypropylene group (-CH(CH₃)CH₂0- or -CH₂CH₂CH₂0-) are preferred, and an oxyethylene group is more preferred.

The compounds shown below are also preferred as the basic compound.

(MO-4)

One of these basic compounds may be used alone, or two or more thereof may be used in combination.

The composition of the present invention may or may not contain a basic compound, but in the case of containing a basic compound, the amount thereof is usually from 0.001 to 10 mass%, preferably from 0.01 to 5 mass%, based on the solid content of the actinic ray-sensitive or radiation-sensitive resin composition.

The ratio between the acid generator (including the acid generator (A')) and the basic compound used in the composition is preferably acid generator/basic compound (by mol) = from 2.5 to 300. That is, the molar ratio is preferably 2.5 or more in view of sensitivity and resolution and preferably 300 or less from the standpoint of suppressing the reduction in resolution due to thickening of the resist pattern with aging after exposure until heat treatment. The acid generator/basic compound (by mol) is more preferably from 5.0 to 200, still more preferably from 7.0 to 150.

The basic resin is preferably used, in terms of a molar ratio to the low molecular compound (D) described in the item [5] later, in a ratio of low molecular compound (D)/basic compound = from 100/0 to 10/90, more preferably from 100/0 to 30/70, still more preferably from 100/0 to 50/50.

Incidentally, the basic compound as used herein excludes (D) a low molecular compound containing a nitrogen atom and having a group capable of leaving by the action of an acid, which is also a basic compound.

[5] Low molecular compound containing a nitrogen atom and having a group capable of leaving by the action of an acid

The composition of the present invention may contain a low molecular compound containing a nitrogen atom and having a group capable of leaving by the action of an acid (hereinafter, sometimes referred to as "low molecular compound (D)" or "component (D)").

The group capable of leaving by the action of an acid is not particularly limited but is preferably an acetal group, a carbonate group, a carbamate group, a tertiary ester group, a tertiary hydroxyl group or a hemiaminal ether group, more preferably a carbamate group or a hemiaminal ether group.

The molecular weight of the (D) low molecular compound having a group capable of leaving by the action of an acid is preferably from 100 to 1,000, more preferably from 100 to 700, still more preferably from 100 to 500.

The compound (D) is preferably an amine derivative having on the nitrogen atom a group capable of leaving by the action of an acid.

The compound (D) may have a protective group-containing carbamate group on the nitrogen atom. The protective group constituting the carbamate group can be represented by the following formula (d- 1 ) :

( d - 1 )

In formula (d-1), each Rb independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkoxyalkyl group. Respective Rb may combine with each other to form a ring.

Each of the alkyl group, cycloalkyl group, aryl group and aralkyl group represented by Rb may be substituted with a functional group such as hydroxyl group, cyano group, amino group, pyrrolidino group, piperidino group, morpholino group and oxo group, an alkoxy group or a halogen atom. The same applies to the alkoxyalkyl group represented by Rb.

Examples of the alkyl group, cycloalkyl group, aryl group and aralkyl group (each of these alkyl group, cycloalkyl group, aryl group and aralkyl group may be substituted with the above-described functional group, an alkoxy group or a halogen atom) of Rb include:

a group derived from a linear or branched alkane such as methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane, undecane and dodecane, or a group where the group derived from an alkane is substituted with one or more kinds of or one or more groups of cycloalkyl groups such as cyclobutyl group, cyclopentyl group and cyclohexyl group;

a group derived from a cycloalkane such as cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, norbornane, adamantane and noradamantane, or a group where the group derived from a cycloalkane is substituted with one or more kinds of or one or more groups of linear or branched alkyl groups such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1 -methylpropyl group and tert-butyl group;

a group derived from an aromatic compound such as benzene, naphthalene and anthracene, or a group where the group derived from an aromatic compound is substituted with one or more kinds of or one or more groups of linear or branched alkyl groups such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1 -methylpropyl group and tert-butyl group;

a group derived from a heterocyclic compound such as pyrrolidine, piperidine, morpholine, tetrahydrofuran, tetrahydropyran, indole, indoline, quinoline, perhydroquinoline, indazole and benzimidazole, or a group where the group derived from a heterocyclic compound is substituted with one or more kinds of or one or more groups of linear or branched alkyl groups or aromatic compound-derived groups; a group where the group derived from a linear or branched alkane/the group derived from a cycloalkane is substituted with one or more kinds of or one or more groups of aromatic compound-derived groups such as phenyl group, naphthyl group and anthracenyl group; and a group where the substituent above is substituted with a functional group such as hydroxyl group, cyano group, amino group, pyrrolidino group, piperidino group, morpholino group and oxo group.

Rb is preferably a linear or branched alkyl group, a cycloalkyl group or an aryl group, more preferably a linear or branched alkyl group or a cycloalkyl group.

Examples of the ring formed by combining two Rb with each other include an alicyclic hydrocarbon group, an aromatic hydrocarbon group, a heterocyclic hydrocarbon group, and derivatives thereof.

Specific structures of the group represented by formula (d-1) are illustrated below.

The compound (D) may also be composed by arbitrarily combining the above-described basic compound and the structure represented by formula (d-1).

The compound (D) is more preferably a compound having a structure represented by the following formula (A).

Incidentally, the compound (D) may be a compound corresponding to the above-described basic compound as long as it is a low molecular compound having a group capable of leaving by the action of an acid.

In formula (A), Ra represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group. Also, when n=2, two Ra may be the same or different, and two Ra may combine with each other to form a divalent heterocyclic hydrocarbon group (preferably having a carbon number of 20 or less) or a derivative thereof.

Rb has the same meaning as Rb in formula (d-1), and preferred examples are also the same, provided that when one or more Rb in -C(Rb)(Rb)(Rb) are a hydrogen atom, at least one of remaining Rb is a cyclopropyl group, a 1-alkoxyalkyl group or an aryl group.

n represents an integer of 0 to 2, m represents an integer of 1 to 3, and n+m=3.

In formula (A), each of the alkyl group, cycloalkyl group, aryl group and aralkyl group represented by Ra may be substituted with the same group as the group which may be substituted on the alkyl group, cycloalkyl group, aryl group and aralkyl group represented by Rb.

Specific examples of the alkyl group, cycloalkyl group, aryl group and aralkyl group (each of these alkyl group, cycloalkyl group, aryl group and aralkyl group may be substituted with the above-described group) of Ra include the same groups as specific examples described above for Rb.

Examples of the divalent heterocyclic hydrocarbon group (preferably having a carbon number of 1 to 20) formed by combining Ra's with each other or a derivative thereof include a group derived from a heterocyclic compound such as pyrrolidine, piperidine, morpholine, 1,4,5,6-tetrahydropyrimidine, 1,2,3,4-tetrahydroquinoline, 1,2,3,6-tetrahydropyridine, homopiperazine, 4-azabenzimidazole, benzotriazole, 5-azabenzotriazole, lH-l,2,3-triazole, 1,4,7-triazacyclononane, tetrazole, 7-azaindole, indazole, benzimidazole, imidazo[l,2-a]pyridine, (l S,4S)-(+)-2,5-diazabicyclo[2.2.1]heptane, l,5,7-triazabicyclo[4.4.0]dec-5-ene, indole, indoline, 1,2,3,4-tetrahydroquinoxaline, perhydroquinoline and 1,5,9-triazacyclododecane, and a group where the group derived from a heterocyclic compound is substituted with one or more kinds of or one or more groups of linear or branched alkane-derived group, cycloalkane-derived group, aromatic compound-derived group, heterocyclic compound-derived group, and functional group such as hydroxyl group, cyano group, amino group, pyrrolidino group, piperidino group, morpholino group and oxo group.

Specific examples of the compound (D) particularly preferred in the present invention are illustrated below, but the present invention is not limited thereto.

(D-52) (D-53) (D-54) (D-55)

The compound represented by formula (A) can be synthesized based on, for example, JP-A-2007-298569 and JP-A-2009- 199021.

In the present invention, as for the (D) low molecular compound containing a nitrogen atom and having a group capable of leaving by the action of an acid, one kind may be used alone, or two or more kinds may be mixed and used.

The actinic ray-sensitive or radiation-sensitive resin composition of the present invention may or may not contain (D) a low molecular compound containing a nitrogen atom and having a group capable of leaving by the action of an acid, but in the case of containing the low molecular compound (D), the content thereof is usually from 0.001 to 20 mass%, preferably from 0.001 to 10 mass%, more preferably from 0.01 to 5 mass%, based on the entire solid compound of the composition combined with the above-described basic compound.

[6] Surfactant

The composition of the present invention may or may not further contain a surfactant, but in the case of containing a surfactant, the surfactant is preferably fluorine-containing and/or silicon-containing surfactants.

Examples of the surfactant coming under these surfactants include Megaface F176 and Megaface R08 (produced by DIC Corporation); PF656 and PF6320 (produced by OMNOVA); Troysol S-366 (produced by Troy Chemical); Florad FC430 (produced by Sumitomo 3M Inc.); and polysiloxane polymer KP-341 (produced by Shin-Etsu Chemical Co., Ltd.).

A surfactant other than the fluorine-containing and/or silicon-containing surfactants may be also used. Specific examples thereof include polyoxyethylene alkyl ethers and polyoxyethylene alkylallyl ethers.

In addition, known surfactants can be appropriately used. Examples of the surfactant which can be used include the surfactants described in paragraph [0273] et seq. of U.S. Patent Application Publication No. 2008/0248425A1.

As for the surfactant, one kind may be used alone, or two or more kinds may be used in combination.

The actinic ray-sensitive or radiation-sensitive resin composition of the present invention may or may not contain a surfactant, but in the case containing a surfactant, the amount of the surfactant used is preferably from 0 to 2 mass%, more preferably from 0.0001 to 2 mass%, still more preferably from 0.0005 to 1 mass%, based on the entire solid content of the composition.

On the other hand, it is also preferred to add the surfactant in an amount of 10 ppm or less or not contain a surfactant. Thanks to this configuration, the hydrophobic resin is more unevenly distributed to the surface, whereby the resist film surface can be made more hydrophobic and the followability of water at the immersion exposure can be enhanced.

[7] Solvent

The solvent that can be used at the time of preparing the composition is not particularly limited as long as it dissolves respective components, but examples thereof include an alkylene glycol monoalkyl ether carboxylate (e.g., propylene glycol monomethyl ether acetate), an alkylene glycol monoalkyl ether (e.g., propylene glycol monomethyl ether), lactic acid alkyl ester (e.g., ethyl lactate, methyl lactate), a cyclic lactone (e.g., γ-butyrolactone, preferably having a carbon number of 4 to 10), a chain or cyclic ketone (e.g., 2-heptanone, cyclohexanone, preferably having a carbon number of 4 to 10), an alkyl carbonate (preferably an alkyl acetate such as butyl acetate), and an alkyl alkoxyacetate (ethyl ethoxypropionate). Other examples of the solvent which can be used include the solvents described in paragraph [0244] et seq. of U.S. Patent Application Publication No. 2008/0248425A1.

Among the solvents above, an alkylene glycol monoalkyl ether carboxylate and an alkylene glycol monoalkyl ether are preferred.

One of these solvent may be used alone, or two or more thereof may be used as a mixture. In the case of mixing two or more solvents, it is preferred to mix a solvent having a hydroxyl group and a solvent not having a hydroxyl group. The mass ratio of the solvent having a hydroxyl group to the solvent not having a hydroxyl group is from 1/99 to 99/1, preferably from 10/90 to 90/10, more preferably from 20/80 to 60/40.

The solvent having a hydroxyl group is preferably an alkylene glycol monoalkyl ether, and the solvent not having a hydroxyl group is preferably an alkylene glycol monoalkyl ether carboxylate.

[8] Other Components

The composition of the present invention may appropriately contain an onium carboxylate, a dissolution inhibiting compound having a molecular weight of 3,000 or less described, for example, in Proceeding of SPIE, 2724, 355 (1996), a dye, a plasticizer, a photosensitizer, a light absorber, and the like, in addition to the above-described components.

[9] Pattern Forming Method

The pattern forming method of the present invention includes steps of exposing and developing a resist film.

The resist film is formed from the above-described actinic ray-sensitive or radiation-sensitive resin composition of the present invention and, more specifically, is preferably formed on a substrate. In the pattern forming method of the present invention, the step of forming a film on a substrate by using a resist composition, the step of exposing the film, and the development step can be performed by generally known methods.

From the standpoint of enhancing the resolution, the actinic ray-sensitive or radiation-sensitive resin composition of the present invention is preferably used in a film thickness of 30 to 250 nm, more preferably from 30 to 200 nm. Such a film thickness can be obtained by setting the solid content concentration in the actinic ray-sensitive or radiation-sensitive resin composition to an appropriate range, thereby imparting an appropriate viscosity and enhancing the coatability and film-forming property.

The entire solid content concentration in the actinic ray-sensitive or radiation-sensitive resin composition of the present invention is generally from 1 to 10 mass%, preferably from 1 to 8.0 mass%, more preferably from 1.0 to 6.0 mass%.

The actinic ray-sensitive or radiation-sensitive resin composition of the present invention is used by dissolving the components above in a solvent and after filtration through a filter, applying the solution on a support. The filter is preferably a polytetrafluoroethylene-, polyethylene- or nylon-made filter having a pore size of 0.1 μιη or less, more preferably 0.05 μπι or less, still more preferably 0.03 μηι or less. A plurality of kinds of filters may be used by connecting the filters in series or in parallel. Also, the composition may be filtered a plurality of times. Furthermore, a deaeration treatment or the like may be applied to the composition before/after filtration through a filter.

The composition is applied on such a substrate (e.g., silicon/silicon dioxide-coated substrate) as used in the production of an integrated circuit device, by an appropriate coating method such as spinner. The coating is then dried, whereby a photosensitive resist film can be formed.

The film is irradiated with an actinic ray or radiation through a predetermined mask, preferably baked (heated) and then subjected to development and rinsing, whereby a good pattern can be obtained. Incidentally, in the case of irradiation with an electron beam, lithography without a mask (direct lithography) is generally performed.

The pattern forming method preferably contains a pre-baking step (PB) after the film formation but before the exposure step.

Also, the pattern forming method preferably contains a post-exposure baking step (PEB) after the exposure step but before the development step.

As for the heating temperature, both PB and PEB are preferably performed at 70 to 120°C, more preferably at 80 to 110°C.

The heating time is preferably from 30 to 300 seconds, more preferably from 30 to 180 seconds, still more preferably from 30 to 90 seconds.

Heating can be performed using a device attached to an ordinary exposure/developing machine or may be performed using a hot plate or the like.

Thanks to baking, the reaction in the exposed area is accelerated, and the sensitivity and pattern profile are improved.

The actinic ray or radiation is not particularly limited but is, for example, KrF excimer laser, ArF excimer laser, EUV light or electron beam, preferably ArF excimer laser, EUV light or electron beam.

As for the alkali developer used in the development step, a quaternary ammonium salt typified by tetramethylammonium hydroxide is usually used, but other than this compound, an aqueous alkali solution of inorganic alkali, primary to tertiary amine, alcohol amine, cyclic amine or the like can also be used.

Furthermore, this alkali developer may be used after adding thereto alcohols and a surfactant each in an appropriate amount.

The alkali concentration of the alkali developer is usually from 0.1 to 20 mass%.

The pH of the alkali developer is usually from 10.0 to 15.0.

As for the rinsing solution, pure water is used, and an appropriate amount of a surfactant may be added thereto before use.

As to the developing method, for example, a method of dipping the substrate in a bath filled with the developer for a fixed time (dipping method), a method of raising the developer on the substrate surface by the effect of a surface tension and keeping it still for a fixed time, thereby performing development (puddle method), a method of spraying the developer on the substrate surface (spraying method), and a method of continuously ejecting the developer on the substrate spinning at a constant speed while scanning the developer ejecting nozzle at a constant rate (dynamic dispense method) may be applied.

After the development step or rinsing step, a treatment of removing the developer or rinsing solution adhering on the pattern by a supercritical fluid may be performed.

Before forming the photosensitive film (resist film), an antireflection film may be previously provided by coating on the substrate.

The antireflection film which can be used may be either an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon and amorphous silicon, or an organic film type composed of a light absorber and a polymer material. As for the organic antireflection film, there may also be used a commercially available organic antireflection film such as DUV30 Series and DUV-40 Series produced by Brewer Science, Inc. and AR-2, AR-3 and AR-5 produced by Shipley Co., Ltd. At the irradiation with an actinic ray or radiation, the exposure may be performed by filling a liquid (immersion medium) having a refractive index higher than that of air between the film and a lens (immersion exposure). By this exposure, the resolution can be enhanced. The immersion medium used is preferably water. Water is preferred also in view of small temperature coefficient of the refractive index, availability and handleability.

Furthermore, from the standpoint that the refractive index can be enhanced, a medium having a refractive index of 1.5 or more may be also used. This medium may be either an aqueous solution or an organic solvent.

In the case of using water as the immersion liquid, an additive for enhancing the refractive index or the like may be added in a slight ratio. Examples of the additive are descried in detail in Ekishin Lithography no Process to Zairyo (Process and Material of Immersion Lithography), Chap. 12, CMC Shuppan. On the other hand, the presence of a substance opaque to light at 193 nm or an impurity greatly differing in the refractive index from water incurs distortion of the optical image projected on the film. Therefore, the water used is preferably distilled water. Pure water after further purification through an ion exchange filter or the like may also be used. The electrical resistance of pure water is preferably 18.3 MQcm or more, and TOC (total organic carbon) is preferably 20 ppb or less. Also, the water is preferably subjected to a deaeration treatment.

In order to prevent the resist film from directly contacting with the immersion liquid, a film (hereinafter, sometimes referred to as a "topcoat") sparingly soluble in the immersion liquid may be provided between the resist film formed and the immersion liquid. The functions required of the topcoat are suitability for coating as an overlayer of the resist, transparency to radiation particularly radiation having a wavelength of 193 nm, and sparing solubility in the immersion liquid. The topcoat is preferably a film unmixable with the resist film and capable of being uniformly applied as an overlayer of the resist.

In view of transparency to light at 193 nm, the topcoat is preferably an aromatic-free polymer, and examples of such a polymer include a hydrocarbon polymer, an acrylic acid ester polymer, a polymethacrylic acid, a polyacrylic acid, a polyvinyl ether, a silicon-containing polymer and a fluorine-containing polymer. The above-described hydrophobic resins is suitable also as the topcoat. If impurities are dissolved out into the immersion liquid from the topcoat, the optical lens is contaminated. Therefore, the amount of residual monomer components of the polymer contained in the topcoat is preferably smaller.

On peeling the topcoat, a developer may be used, or a releasing agent may be separately used. The releasing agent is preferably a solvent less permeating the resist. From the standpoint that the peeling step can be performed simultaneously with the development step of the resist, the topcoat is preferably peelable with an alkali developer and from the standpoint of peeling with an alkali developer, the topcoat is preferably acidic, but in view of non-intermixing with the resist, the topcoat may be neutral or alkaline.

The difference in the refractive index between the topcoat and the immersion liquid is preferably null or small. In this case, the resolution can be enhanced. In the case where the exposure light source is an ArF excimer laser (wavelength: 193 nm), water is preferably used as the immersion liquid and therefore, the topcoat for ArF immersion exposure preferably has a refractive index close to the refractive index (1.44) of water.

Also, in view of transparency and refractive index, the topcoat is preferably a thin film. The topcoat is preferably unmixable with the resist film and further unmixable with the immersion liquid. From this standpoint, when the immersion liquid is water, the solvent used for the topcoat is preferably a medium that is sparingly soluble in the solvent used for the actinic ray-sensitive or radiation-sensitive resin composition of the present invention resin and insoluble in water. Furthermore, when the immersion liquid is an organic solvent, the topcoat may be either water-soluble or water-insoluble.

The present invention also relates to a method for manufacturing an electronic device, including the pattern forming method of the present invention, and an electronic device manufactured by this manufacturing method.

The electronic device of the present invention is suitably mounted on electric electronic equipment (such as home electronic device, OA^»media-related device, optical device and communication device).

Examples

The present invention is described in greater detail below by referring to Examples, but the present invention is not limited thereto.

[Synthesis Example 1 : Synthesis of Compound A-6]

9-Ethylcarbazole-2,7-ditetrahydrothiophenium dinonafluorobutanesulfonate

Ethylcarbazole (5 g) and 11.7 g of tetramethylene sulfoxide were dissolved in 80 g of dichloromethane, and the solution was cooled to -50°C. Thereto, 23.7 g of trifluacetic anhydride and 16.9 g of trifluoromethanesulfonic acid were slowly added dropwise, and the temperature was raised to -20°C. After stirring for 2 hours, the temperature was raised to room temperature, and a potassium nonafluorobutanesulfonate 25 g solution having dissolved therein 150 g of water and 50 g of acetonitrile was added. After stirring for 30 minutes, the dichloromethane layer was washed with pure water three times, and the solvent was then removed by distillation under reduced pressure. The residue was slurried with cyclopentylmethyl ether to obtain 23.6 g of Compound A-6 shown below.

1H-NMR (300 MHz, CDC1₃): 59.0 (s. 2H), 67.9 (d. 2H), 57.65 (d. 2H), 54.3 (q. 2H), 54.1 (m. 4H), 53.9 (m. 4H), 52.8 (m. 4H), 52.4 (m, 4H), 51.4 (t. 3H).

Other photoacid generators shown in Table 2 later were synthesized by the same method as in Synthesis Example 1.

[Synthesis Example 2: Synthesis of Resin c]

In a nitrogen stream, 11.5 g of cyclohexanone was charged into a three-neck flask and heated at 85°C. Thereto, a solution obtained by dissolving the following compounds (monomers) in amounts of, starting from the left, 1.98 g, 3.05 g, 0.95 g, 2.19 g and 2.76 g and polymerization initiator V-601 (produced by Wako Pure Chemical Industries, Ltd., 0.599 g) in 21.0 g of cyclohexanone was added dropwise over 6 hours. After the completion of dropwise addition, the reaction was further allowed to proceed at 85°C for 2 hours. The reaction solution was left to cool and then added dropwise to a mixed solution of 420 g of hexane/180 g of ethyl acetate over 20 minutes, and the precipitated powder was collected by filtration and dried to obtain 9.1 g of Resin c. The polymer compositional ratio (molar ratio) as determined from NMR was 20/25/10/30/15. The weight average molecular weight of Resin c obtained was 9,200 in terms of standard polystyrene, and the polydispersity (Mw/Mn) was 1.55.

Resins a, b and d to f were synthesized by the same operation as in Synthesis Example 2.

Preparation of Actinic Ray-Sensitive or Radiation-Sensitive Resin Composition>

The components shown in Table 2 below were dissolved in a solvent to prepare a solution having a solid content concentration of 4 mass%, and the solution was filtered through a polyethylene filter having a pore size of 0.05 μηι to prepare an actinic ray-sensitive or radiation-sensitive resin composition. The actinic ray-sensitive or radiation-sensitive resin compositions were evaluated by the following methods, and the results are shown in Table 2.

As for each component in the Table, the ratio when using a plurality of kinds is a ratio by mass.

Incidentally, in Table 2, when the actinic ray-sensitive or radiation-sensitive resin composition contained a hydrophobic resin (HR), the mode of use is denoted by "added", and when the actinic ray-sensitive or radiation-sensitive resin composition did not contain a hydrophobic resin (HR) and after the formation of a film, a topcoat protective film containing a hydrophobic resin (HR) was formed as an overlayer of the film, the mode of use is denoted by "TC".

(Exposure Condition 1: ArF immersion exposure) (Examples 1 to 10 and 13 to 23, Comparative Examples 1 and 2)

An organic antireflection film, ARC29SR (produced by Nissan Chemical Industries, Ltd.), was applied on a 12-inch silicon wafer and baked at 205°C for 60 seconds to form an antireflection film having a thickness of 98 nm, and the actinic ray-sensitive or radiation-sensitive resin composition prepared above was applied thereon and baked at 130°C for 60 seconds to form a resist film having a thickness of 120 nm. In the case of using a topcoat, a solution with a concentration of 3 mass% prepared by dissolving the hydrophobic resin (HR) shown in Table 2 below as a topcoat resin in decane/octanol (mass ratio: 9/1) was applied on the film obtained above and then baked at 85°C for 60 seconds to form a topcoat layer having a thickness of 50 nm. The resulting wafer was exposed through a 6% halftone mask having a 1 : 1 line-and-space pattern with a line width of 48 nm by using an ArF excimer laser immersion scanner (XT1700i, manufactured by ASML, NA: 1.20, C-Quad, outer sigma: 0.981 , inner sigma: 0.895, XY deflection). As for the immersion liquid, ultrapure water was used. Thereafter, the wafer was heated at 100°C for 60 seconds, developed by puddling an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsed by puddling pure water, and then spin-dried to form a pattern.

(Exposure Condition 2: ArF dry exposure) (Examples 11 and 12)

An organic antireflection film, ARC29A (produced by Nissan Chemical Industries, Ltd.), was applied on a 12-inch silicon wafer and baked at 205°C for 60 seconds to form an antireflection film having a thickness of 78 nm, and the positive resist composition prepared was applied thereon and baked at 130°C for 60 seconds to form a resist film having a thickness of 120 nm. The obtained wafer was exposed through a 6% halftone mask having a 1 : 1 line-and-space pattern with a line width of 75 nm by using an ArF excimer laser scanner (PAS5500/1100, manufactured by ASML, NA: 0.75, Dipole, σο/σί=0.89/0.65), then heated at 100°C for 60 seconds, developed with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsed with pure water, and spin-dried to obtain a resist pattern. (Evaluation of Exposure Sensitivity)

The exposure dose for resolving a line-and-space mask pattern with a line width of 48 nm in Exposure Condition 1 and a line-and-space mask pattern with a line width of 75 nm in Exposure Condition 2 was taken as the optimal exposure dose and used as an index of exposure sensitivity. A smaller value indicates a higher performance.

(Evaluation of Development Defect)

Using a defect inspection apparatus, KLA 2360 (trade name), manufactured by LA Tencor Ltd., measurement was performed in a random mode by setting the pixel size of the defect inspection apparatus to 0.16 μιη and the threshold value to 20. Development defects extracted from the difference produced when superposing pixel units with a reference image were detected, and the number of development defects per unit area (1 cm ) was computed. A smaller value indicates a higher performance.

Table 2

Table 2 continued

Abbreviations in the Table stand for those illustrated in specific examples above or the followings.

[Compound (A)]

Other Acid Generators]

PAG-X PAG-Y

[Resin (B)]

In each of the following Resins a to f, the compositional ratio of repeating units is the molar ratio.

[Basic Compound] DIA: 2,6-Diisopropylaniline

TEA: Triethanolamine

DBA: N,N-Dibutylaniline

PBI: 2-Phenylbenzimidazole

PEA: N-Phenyldiethanolamine

[(D) Low Molecular Compound Having a Group Capable of Leaving by the Action of (Compound (D))]

[Surfactant]

W-l : Megaface F176 (produced by DIC Corporation) (fluorine-containing)

W-2: Megaface R08 (produced by DIC Corporation) (fluorine- and silicon-containing)

W-3: PF6320 (produced by OMNOVA Solutions Inc.) (fluorine-containing)

W-4: Troysol S-366 (produced by Troy Chemical)

[Solvent]

Al : Propylene glycol monomethyl ether acetate (PGMEA)

A2: Cyclohexanone

A3: γ-Butyrolactone

B 1 : Propylene glycol monomethyl ether (PGME)

B2: Ethyl lactate

As apparent from the results shown in Table 2, in both of Comparative Example 1 where an acid generator having one sulfonium structure is used, and Comparative Example 2 where the acid generator has two sulfonium structures but does not satisfy formula (I), the exposure sensitivity is low (the optimal exposure dose is large) and the number of development defects is large.

On the other hand, in Examples 1 to 23 where the compound (A) represented by formula (I) is used as an acid generator, the exposure sensitivity is high (the optimal exposure dose is small) and the number of development defects is small.

Industrial Applicability

According to the actinic ray-sensitive or radiation-sensitive resin composition, and the resist film and the pattern forming method each using the composition, excellent high exposure sensitivity and little development defect are ensured. The actinic ray-sensitive or radiation-sensitive resin composition of the present invention can be suitably used, for example, for an ArF immersion exposure process.

Also, the pattern forming method of the present invention can provide a manufacturing method of an electronic device, and an electronic device manufactured by the manufacturing method.

This application is based on Japanese patent application No. JP 2011-153233 filed on July 11, 2011, the entire content of which is hereby incorporated by reference, the same as if set forth at length.

Claims

1. An actinic ray-sensitive or radiation-sensitive resin composition, comprising:

(A) a compound represented by the following formula (I); and

(B) a resin:

wherein X represents an oxygen atom, a sulfur atom or -N(Rx)-;

each of Ri to R₈ and Rx independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an acyl group, an alkylcarbonyloxy group, an aryl group, an aryloxy group, an aryloxycarbonyl group or an arylcarbonyloxy group; and

Ri to R₈ may combine with each other to form a ring,

provided that at least two members out of Rj to R₈ represent a structure represented by the following formula (II):

wherein each of R and R₁₀ independently represents an alkyl group, a cycloalkyl group or an aryl group when X is an oxygen atom or a sulfur atom, and independently represents an alkyl group or a cycloalkyl group when X is -N(Rx)-, and each R₉ and each Rio may be the same as or different from every other R₉ and every other R₁₀, respectively;

R9 and Rio may combine with each other to form a ring; and

Z^" represents a non-nucleophilic anion, each Z^" may be the same as or different from every other Z^", and a plurality of Z 's may combine to form a polyvalent non-nucleophilic anion.

2. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1,

wherein Z in formula (II) is a sulfonate anion.

3. The actinic ray-sensitive or radiation-sensitive resin composition according to " in formula (II) is an anion represented by the following formula (III):

each of Rn and R]₂ independently represents a hydrogen atom, a fluorine atom, an alkyl group or an alkyl group substituted with at least one fluorine atom, and when a plurality of Ru's and a plurality of Ri₂'s are present, each R and each R_]2 may be the same as or different from every other Ru and every other R₁₂, respectively;

L represents a divalent linking group, and when a plurality of L's are present, each L may be the same as or different from every other L;

A represents a cyclic organic group; and

4. The actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 3,

wherein each of R9 and Ri₀ in formula (II) is independently an alkyl group or a cycloalkyl group, and R₉ and Rio may combine with each other to form a ring.

5. The actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 4,

wherein R9 and Rio in formula (II) are combined to form a ring.

6. The actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 5,

wherein X represents -N(Rx)-, Rx in formula (I) is an alkyl group, a cycloalkyl group or an aryl group each having a structure represented by formula (II) as a substituent, and at least one member out of Ri to R₈ is a structure represented by formula (II).

7. The actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 6,

8. A resist film, which is formed by using the actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 7.

9. A pattern forming method, comprising:

a step of exposing the resist film according to claim 8, so as to form an exposed resist film; and

a step of developing the exposed resist film.

10. The pattern forming method according to claim 9,

wherein the exposure is immersion exposure.

11. A manufacturing method of an electronic device, comprising:

the pattern forming method according to claim 9 or 10.

12. An electronic device, which is manufactured by the manufacturing method of an electronic device according to claim 11.