WO2011108744A1

WO2011108744A1 - Actinic ray-sensitive or radiation-sensitive resin composition, and resist film and pattern forming method using the same

Info

Publication number: WO2011108744A1
Application number: PCT/JP2011/055180
Authority: WO
Inventors: Yusuke Iizuka; Hidenori Takahashi; Shuji Hirano; Masahiro Yoshidome; Michihiro Shirakawa
Original assignee: Fujifilm Corporation
Priority date: 2010-03-01
Filing date: 2011-03-01
Publication date: 2011-09-09
Also published as: JP2011180393A

Abstract

An actinic ray-sensitive or radiation-sensitive resin composition comprising: (A) a resin containing (a1) a repeating unit having (S1) a structural moiety capable of decomposing by the action of an acid to produce an alkali-soluble group and (S2) a structural moiety capable of increasing the dissolution rate in an alkali developer by the action of an alkali developer; (B) a resin having at least either a fluorine atom or a silicon atom; and (C) a compound capable of generating an acid upon irradiation with an actinic ray or radiation.

Description

DESCRIPTION

Title of Invention

ACTINIC RAY-SENSITIVE OR RADIATION-SENSITIVE RESIN COMPOSITION, AND RESIST FILM AND PATTERN FORMING METHOD USING THE SAME

Technical Field

The present invention relates to an actinic ray-sensitive or radiation-sensitive resin composition, and a resist film and a pattern forming method each using the composition. More specifically, the present invention relates to a composition suitably used in the ultramicrolithography process applicable to, for example, the production process of VLSI or a high-capacity microchip, the preparation process of a nanoimprint mold, or the production process of a high-density information recording medium, and in other photofabrication processes, and a pattern forming method using the composition. In particular, the present invention relates to a composition suitable for exposure by an immersion projection exposure apparatus using a light source that emits far ultraviolet light at a wavelength of 300 nm or less, and a pattern forming method using the composition.

Background Art

Along with miniaturization of a semiconductor device, the trend is moving into a shorter wavelength of the exposure light source and a higher numerical aperture (higher NA) of the projection lens, and a so-called immersion method of filling a high refractive-index liquid (hereinafter sometimes referred to as an "immersion liquid") between the projection lens and the sample with an attempt to raise the resolution by more shortening the wavelength is known. The immersion method is effective for all pattern profiles and furthermore, can be combined with the super-resolution technology under study at present, such as phase-shift method and modified illumination method.

Since the advent of a resist for KrF excimer laser (248 nm), an image forming method called chemical amplification is used as an image forming method for a resist so as to compensate for sensitivity reduction caused by light absorption. For example, the image forming method by positive chemical amplification is an image forming method of decomposing an acid generator in the exposed area upon exposure to produce an acid, converting an alkali-insoluble group into an alkali-soluble group by using the generated acid as a reaction catalyst in the baking after exposure (PEB: Post Exposure Bake), and removing the exposed area by alkali development.

A resist for ArF excimer laser (193 nm) using this chemical amplification mechanism is predominating at present, but when immersion exposure is performed, this is faced with a Line Width Roughness problem that the pattern side wall is roughened.

In recent years, it has been found that the roughness characteristics such as line edge roughness can be improved by incorporating a repeating unit having a specific lactone structure into a resin having the above-described alicyclic hydrocarbon structure.

Furthermore, in the immersion exposure process, when the exposure is performed using a scanning-type immersion exposure machine, unless the immersion liquid moves following the movement of lens, the exposure speed decreases and this may affect the productivity. Therefore, when the immersion liquid is water, the resist film preferably allows for good followability of water.

For example, Japanese Patent 4,288,518 describes a resin containing a repeating unit having a structure where an acid-decomposable group is bonded to a specific position of a norbornane structure, and a resist composition containing the resin. In this document, it is stated that the pattern profile, exposure margin and the like can be improved by using such a composition.

Also, JP-A-2008-231059 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") describes a polymer compound containing a repeating unit having a specific lactone structure with an electron- withdrawing group, and a resist composition containing the polymer compound. In this document, it is stated that this polymer compound is excellent in the solvent solubility, hydrolyzability and the like.

However, the pattern obtained by the techniques described in Japanese Patent 4,288,518 and JP-A-2008-231059 has a problem that the development defect and pattern collapse are likely to be caused.

Summary of Invention An object of the present invention is to provide an actinic ray-sensitive or radiation-sensitive resin composition capable of forming a pattern improved in the line width roughness, development defect and pattern collapse and assured of good foUowability of an immersion liquid, and a resist film and a pattern forming method each using the composition

As a result of intensive studies, the present inventors presumed that the cause responsible for easy generation of a development defect and pattern collapse when using a resin described in Japanese Patent 4,288,518 and JP-A-2008-231059 is some adverse effect of the acid-decomposable group bonded to a specific position of a norbornane structure in Japanese Patent 4,288,518 and the electron- withdrawing group in JP-A- 2008-231059. Particularly, in Japanese Patent 4,288,518, the present inventors presumed, the acid-decomposable group of the resin excessively enhances the hydrophilicity of the resist film, and the developer and the rinsing solution usable for washing the pattern after the development step readily permeate the obtained pattern, which gives rise to the generation of collapse of the formed line pattern or a development defect.

Under these presumptions, the present inventors have found that when (a) a resin containing a repeating unit having a structure capable of increasing the dissolution rate in an alkali developer by the action of an alkali developer (for example, a lactone structure) and an acid-decomposable group and (b) a resin having at least either a fluorine atom or a silicon atom are used in combination, not only the development defect and pattern collapse are greatly improved but also excellent performances can be obtained in terms of the line width roughness and foUowability of an immersion liquid at the immersion exposure. The present invention has been accomplished based on this finding.

The operational effect of this development is not completely clarified, but it is presumed that the resin (b) having certain hydrophobicity keeps the hydrophilicity of a resist film from being greatly increased by the acid-decomposable group of the resin (a) and thereby reduces the collapse of a line pattern or the generation of a development defect and at the same time, in the exposed area, a structure or group having high affinity for an alkali developer (for example, the above-described structure capable of increasing the dissolution rate in an alkali developer by the action of an alkali developer or an alkali-soluble group produced from the acid-decomposable group), contained in the resin (a), allows an alkali developer to unfailingly remove the exposed area and thus, ensures very excellent performance in terms of line width roughness.

That is, the present invention is as follows.

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

(A) a resin containing (al) a repeating unit having (SI) a structural moiety capable of decomposing by the action of an acid to produce an alkali-soluble group and (S2) a structural moiety capable of increasing the dissolution rate in an alkali developer by the action of an alkali developer,

(B) a resin having at least either a fluorine atom or a silicon atom, and

(C) a compound capable of generating an acid upon irradiation with an actinic ray or radiation.

[2] The actinic ray-sensitive or radiation-sensitive resin composition according to [1] above, wherein the resin (B) contains a repeating unit having at least one 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 in an alkali developer, and

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

[3] The actinic ray-sensitive or radiation-sensitive resin composition according to

[2] above, wherein the repeating unit having at least one group selected from the group consisting of (x) to (z) has at least either a fluorine atom or a silicon atom.

[4] The actinic ray-sensitive or radiation-sensitive resin composition according to

[2] or [3] above, wherein the repeating unit having at least one group selected from the group consisting of (x) to (z), contained in the resin (B), is (by) a repeating unit having the group (y).

[5] The actinic ray-sensitive or radiation-sensitive resin composition according to [4] above, wherein the repeating unit (by) has at least one of partial structures represented by the following formulae (KA-1) and (KB-1) and the group (y) is represented by X in the partial structure of formula (KA-1) or (KB-1).

wherein X represents a carboxylic acid ester group, an acid anhydride group, an acid imide group, a carboxylic acid thioester group, a carbonic acid ester group, a sulfuric acid ester group or a sulfonic acid ester group, and

each of Y¹ and Y², which may be the same or different, represents an electron- withdrawing group.

[6] The actinic ray-sensitive or radiation-sensitive resin composition according to [5] above, wherein the repeating unit (by) has a partial structure represented by formula (KA-1) and X in formula (KA-1) is a carbonic acid ester group.

[7] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [6] above, wherein the structural moiety (S2) contains a lactone structure.

[8] The actinic ray-sensitive or radiation-sensitive resin composition according to

[7] above, wherein the structural moiety (S I) is bonded to a ring structure containing the lactone structure of the structural moiety (S2).

[9] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [8] above, wherein the repeating unit (al) is a repeating unit containing a structural moiety represented by the following formula (1):

wherein Li represents a single bond, an alkylene group, an alkenylene group, a divalent aliphatic hydrocarbon ring group, a divalent aromatic ring group, or a group composed of a combination of two or more thereof and when a plurality of L_\ s are present, each Li may be the same as or different from every other

R₃ represents an alkyl group or a monovalent aliphatic hydrocarbon ring group and when a plurality of R₃'s are present, each R₃ may be the same as or different from every other R₃ and the plurality of R₃'s may combine with each other to form a ring;

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

Y represents said structural unit (SI) and when a plurality of Y's are present, each Y may be the same as or different from every other Y;

Zi2 represents a single bond, -0-, -S-, -CO-, -S0₂-, -NR-, a divalent nitrogen- containing non-aromatic heterocyclic group, or a group composed of a combination thereof and when a plurality of Z]₂'s are present, each Z]₂ may be the same as or different from every other Z₁₂;

R represents a hydrogen atom or an alkyl group;

k represents an integer of 0 to 5;

m represents an integer of 1 to 5 satisfying the relationship of m+k<6; and n represents an integer of 0 to 5.

[10] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [9] above, wherein the content of the resin (B) is from 0.01 to 20 mass% based on the entire solid content of the actinic ray-sensitive or radiation- sensitive resin composition.

[1 1] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [10] above, wherein the content of the resin (B) is from 0.1 to 15 mass% based on the entire solid content of the actinic ray-sensitive or radiation- sensitive resin composition.

[12] A resist film formed from the actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [11] above.

[13] A pattern forming method comprising steps of exposing and developing the resist film according to [12] above.

[14] The pattern forming method according to [13] above, wherein the exposure is performed through an immersion liquid.

Furthermore, the present invention preferably has the following configurations.

[15] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [1 1] above, wherein at least either the resin (A) and the resin (B) contains a lactone structure.

[16] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [7] to [11] above, wherein the structural moiety (SI) is bonded to at least one of two carbon atoms adj acent to an ester group constituting a lactone structure contained in the structural moiety (S2).

[17] The actinic ray-sensitive or radiation-sensitive resin composition according to [16] above, wherein the structural moiety (SI) is bonded to carbon directly bonded to the carbonyl carbon, out of those two carbon atoms.

[18] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [11] and [15] to [17] above, wherein the structural moiety (SI) contains an acid-decomposable group containing an alicyclic structure.

[19] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [11] and [15] to [18] above, wherein the structural moiety (SI) is a group represented by the following formula (S 1-1):

R₄

Z₂₁ L₂— COO— |-R₅ (S1-1 )

R₆ wherein Z₂₁ represents a single bond, -0-, -S-, -CO-, -S0₂-, -NR-, a divalent nitrogen-containing non-aromatic heterocyclic group, or a group composed of a combination thereof;

L₂ represents a single bond, an alkylene group, an alkenylene group, a divalent aliphatic hydrocarbon ring group, a divalent aromatic ring group, or a group composed of a combination of two or more thereof, and in the group composed of a combination, two or more groups combined may be the same or different and may be connected through a linking group of -0-, -S-, -CO-, -S0₂-, -NR-, a divalent nitrogen- containing non-aromatic heterocyclic group or a group composed of a combination thereof;

R represents a hydrogen atom or an alkyl group;

R_t represents an alkyl group; and

each of R₅ and R<$ independently represents an alkyl group or a monovalent aliphatic hydrocarbon ring group, and R₅ and R₆ may combine with each other to form a ring.

[20] The actinic ray-sensitive or radiation-sensitive resin composition as described in any one of [1] to [11] and [15] to [19] above, wherein the repeating unit (al) is re resented by the following formula (Al):

wherein each of Rn to R₁₃ independently represents a hydrogen atom, an alkyl group or a halogen atom;

R₁₂ may combine with _\ to form a ring and the ring may be monocyclic or polycyclic;

L] represents a single bond, an alkylene group, an alkenylene group, a divalent aliphatic hydrocarbon ring group, a divalent aromatic ring group, or a group composed of a combination of two or more thereof, each Li may be the same as or different from every other Li when a plurality of Li's are present, and in the group composed of a combination, two or more groups combined may be the same or different and may be connected through a linking group of -0-, -S-, -CO-, -S0₂-, -NR-, a divalent nitrogen-containing non-aromatic heterocyclic group or a group composed of a combination thereof;

provided that when a ring is formed together with R₁₂, L₁ represents a trivalent or higher valent group resulting from removing one or more arbitrary hydrogen atoms of a divalent group as Li;

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

Y represents the structural unit (SI) and when a plurality of Y's are present, each Y may be the same as or different from every other Y;

each of Z_\ and Zi₂ independently represents a single bond, -0-, -S-, -CO-, - S0₂-, -NR-, a divalent nitrogen-containing non-aromatic heterocyclic group or a group composed of a combination thereof and when a plurality of Zi₂'s are present, each Zj₂ may be the same as or different from every other Z₁₂;

R represents a hydrogen atom or an alkyl group;

k represents an integer of 0 to 5;

[21] The actinic ray-sensitive or radiation-sensitive resin composition according to any one of [1] to [11] and [15] to [20] above, wherein the repeating unit (al) is represented by the following formula (A2):

wherein Rn represents a hydrogen atom or an alkyl group:

Li represents a single bond, an alkylene group, an alkenylene group, a divalent aliphatic hydrocarbon ring group, a divalent aromatic ring group, or a group composed of a combination of two or more thereof and when a plurality of Li's are present, each Li may be the same as or different from every other L_\;

each of Z_{\ \} and Z₁₂ independently represents a single bond, -0-, -S-, -CO-, - S0₂-, -NR-, a divalent nitrogen-containing non-aromatic heterocyclic group, or a group composed of a combination thereof and when a plurality of Zj₂'s are present, each Z_J2 may be the same as or different from every other Z₁₂;

R4 represents an alkyl group;

each of R₅ and R₆ independently represents an alkyl group or a monovalent aliphatic hydrocarbon ring group, and R₅ and R^ may combine with each other to form a ring; X represents an alkylene group, an oxygen atom or a sulfur atom;

Z₂i represents a single bond, -0-, -S-, -CO-, -S0₂-, -NR-, a divalent nitrogen- containing non-aromatic heterocyclic group, or a group composed of a combination thereof;

R represents a hydrogen atom or an alkyl group;

k represents an integer of 0 to 5; and

n represents an integer of 0 to 5.

[22] The actinic ray-sensitive or radiation-sensitive resin composition according to [6] above, wherein the repeating unit (by) is a repeating unit having a partial structure represented by the following formula (KY-0):

wherein R₂ represents a chain or cyclic alkylene group and when a plurality of R₂'s are present, each R₂ may be the same as or different from every other R₂;

R₃ represents a linear, branched or cyclic hydrocarbon group in which hydrogen atoms on constituent carbons are partially or entirely substituted for 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) and when a plurality of Rj's are present, each R₄ may be the same as or different from every other R₄ and two or more R^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 are present, each Z may be the same as or different from every other Z;

* represents a bond to the main chain 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; and n is a repetition number and represents an integer of 0 to 5.

According to the present invention, an actinic ray-sensitive or radiation- sensitive resin composition improved in the line width roughness, development defect and pattern collapse and excellent in the foUowability of an immersion liquid at immersion exposure, and a resist film and a pattern forming method each using the composition can be provided.

Description of Embodiments

Embodiments of the present invention are described in detail below.

Incidentally, a group or atomic group as denoted herein without specifying whether substituted or unsubstituted includes both a group having no substituent and a group having a substituent. For example, an "alkyl group" includes, when whether substituted or unsubstituted is unspecified, not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

Also, in the present invention, the term "actinic ray" or "radiation" indicates, for example, a bright line spectrum of a mercury lamp, a far ultraviolet ray typified by an excimer laser, an extreme-ultraviolet (EUV) ray, an X-ray or an electron beam (EB). Furthermore, in the present invention, the "light" means an actinic ray or radiation. In the present invention, unless otherwise indicated, the "exposure" includes not only exposure with a mercury lamp, a far ultraviolet ray, 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 comprises:

(A) a resin containing a repeating unit having (SI) a structural moiety capable of decomposing by the action of an acid to produce an alkali-soluble group and (S2) a structural moiety capable of increasing the dissolution rate in an alkali developer by the action of an alkali developer,

(B) a resin having at least either a fluorine atom or a silicon atom, and

According to the actinic ray-sensitive or radiation-sensitive resin composition of the present invention, the line width roughness, development defect and pattern collapse can be improved and furthermore, the followability of an immersion liquid at immersion exposure can be improved.

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. The configuration of this composition is described below.

[1] Resin (A)

The resin (A) contains (al) a repeating unit having (SI) a structural moiety capable of decomposing by the action of an acid to produce an alkali-soluble group and (S2) a structural moiety capable of increasing the dissolution rate in an alkali developer by the action of an alkali developer.

[Repeating Unit (al)]

As described above, the repeating unit (al) has (SI) a structural moiety capable of decomposing by the action of an acid to produce an alkali-soluble group and (S2) a structural moiety capable of increasing the dissolution rate in an alkali developer by the action of an alkali developer.

The repeating unit (al) may be (al') a repeating unit having the structural moiety (SI) and the structural moiety (S2) on one side chain or (al ") a repeating unit having the structural moiety (SI) on one side chain and having the structural moiety (S2) on a side chain different the side chain above in the same repeating unit, but the repeating unit (al) is preferably a repeating unit (al¹).

The structural moiety (S2) possessed by the repeating unit (al) is not particularly limited as long as it is a structural moiety capable of decomposing by the action of an alkali developer to increase the dissolution rate in an alkali developer, but examples of the group capable of decomposing by the action of an alkali developer to increase the dissolution rate in an alkali developer include a structural moiety containing an aryl ester structure or a lactone structure. The structural moiety (S2) is preferably a structural moiety containing a lactone structure and by employing, as the structural moiety (S2), a structure containing a lactone structure, for example, the adherence to a substrate can be improved.

The structural moiety (SI) possessed by the repeating unit (al) is not particularly limited as long as it is a structural moiety capable of decomposing by the action of an acid to produce an alkali-soluble group.

In the case where the structural moiety (S2) contains a lactone structure, the structural moiety (SI) is preferably bonded to a lactone structure-containing ring structure (lactone ring) as shown in the following chemical formula. Employment of such a configuration makes it possible to more enhance, for example, the hydrolability of the resin and the performance of the composition in terms of development defect.

o

In the formula, SI represents a group corresponding to the structural moiety (SI), and the dash part represents an atomic group necessary for forming a lactone ring together with the ester group.

The structural moiety (SI) is preferably bonded to at least one of two carbon atoms adjacent to the ester group constituting the lactone structure. That is, the repeating unit (al) preferably contains a structure represented by the following formula (4-1) or (4-2). The repeating unit (al) more preferably contains a structure in which the structural moiety (S I) is bonded, out of those two carbon atoms, to carbon directly bonded to carbonyl carbon, that is, a structure represented by the following formula (4- 1)·

Employment of the above-described configuration makes it possible to more enhance, for example, the hydrolability of the resin and the performance of the composition in terms of development defect.

The structural moiety (SI) is preferably a group represented by "-(a linking group)-(an acid-decomposable group)". Here, the acid-decomposable group is preferably a group represented by "-(a group resulting from removing hydrogen atom of an alkali-soluble group)-(a group capable of leaving by the action of an acid)".

Examples of the alkali-soluble group include a phenolic hydroxyl group, a carboxy 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 carboxy group, a fluorinated alcohol group and a sulfonic acid group. The fluorinated alcohol group is preferably a hexafluoroisopropanol group.

Examples of the group capable of leaving by the action of an acid include groups represented by -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 monovalent aliphatic hydrocarbon ring group (cycloalkyl group), a monovalent aromatic ring group (aryl group), a group formed by combining an alkylene group and a monovalent aromatic ring group (aralkyl group) or an alkenyl group. R₃ and R₃₇ may combine with each other to form a ring. Each of Roi and Ro₂ independently represents a hydrogen atom, an alkyl group, a monovalent aliphatic hydrocarbon ring group, a monovalent aromatic ring group, an aralkyl group or an alkenyl group, provided that R₀i and R₀₂ are not a hydrogen atom at the same time.

Preferred examples of the acid-decomposable group include a cumyl ester group, an enol ester group, an acetal ester group and a tertiary alkyl ester group, with a tertiary alkyl ester group being more preferred.

The acid-decomposable group preferably contains an alicyclic structure (which may be monocyclic or polycyclic). That is, the structural moiety (SI) preferably contains an acid-decomposable group containing an alicylcic structure (in other words, the resin (A) preferably contains (al) a repeating unit having an acid- decomposable group containing an alicyclic structure). Employment of such a configuration makes it possible to more enhance, for example, the dry etching resistance and resolution.

Although not particularly limited, the structural moiety (SI) is more preferably a group represented by the following formula (S 1 - 1 ) :

R₄

Z₂₁ L₂— COO— j-R₅ (S1-1 )

R₆

wherein Z₂i represents a single bond, -0-, -S-, -CO-, -S0₂-, -NR-, a divalent nitrogen-containing non-aromatic heterocyclic group, or a group composed of a combination thereof; L₂ represents a single bond, an alkylene group, an alkenylene group, a divalent aliphatic hydrocarbon ring group, a divalent aromatic ring group, or a group composed of a combination of two or more thereof, and in the group composed of a combination, two or more groups combined may be the same or different and may be connected through a linking group of -0-, -S-, -CO-, -S0₂-, -NR-, a divalent nitrogen- containing non-aromatic heterocyclic group or a group composed of a combination thereof; R represents a hydrogen atom or an alkyl group; R4 represents an alkyl group; and each of R₅ and R^ independently represents an alkyl group or a monovalent aliphatic hydrocarbon ring group, and R₅ and R6 may combine with each other to form a ring.

In -NR- as Z₂i, the alkyl group represented by R is a linear or branched alkyl group which may have a substituent and is preferably an alkyl group having a carbon number of 20 or less, which may have a substituent, such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, hexyl group, 2- ethylhexyl group, octyl group and dodecyl group, more preferably an alkyl group having a carbon number of 8 or less, still more preferably an alkyl group having a carbon number of 3 or less. R is preferably a hydrogen atom, a methyl group or an ethyl group.

The divalent nitrogen-containing non-aromatic heterocyclic group as Z₂i means preferably a 3- to 8-membered non-aromatic heterocyclic group having at least one nitrogen atom, and specific examples thereof include divalent linking groups having the followin structures.

Z₂i is preferably a single bond, -0-, -OCO-, -COO-, -OS0₂-, -S0₃-, -CONR-, or a group formed by combining -CO- and a divalent nitrogen-containing non-aromatic heterocyclic group, more preferably a single bond, -COO-, -S0₃- or -CONR-, still more preferably a single bond or -COO-.

The alkylene group in L₂ may be linear or branched, and preferred examples thereof include an alkylene group having a carbon number of 1 to 8, such as methylene group, ethylene group, propylene group, butylene group, hexylene group and octylene group. An alkylene group having a carbon number of 1 to 6 is more preferred, and an alkylene group having a carbon number of 1 to 4 is still more preferred.

The alkenylene group in L₂ includes a group having a double bond at an arbitrary position of the above-described alkylene group except for a methylene group.

The divalent aliphatic hydrocarbon ring group in L₂ may be either monocyclic or polycyclic, and preferred examples thereof include a divalent aliphatic hydrocarbon ring group having a carbon number of 3 to 17, such as cyclobutylene group, cyclopentylene group, cyclohexylene group, norbornanylene group, adamantylene group and diamantanylene group. A divalent aliphatic hydrocarbon ring group having a carbon number of 5 to 12 is more preferred, and a divalent aliphatic hydrocarbon ring group having a carbon number of 6 to 10 is still more preferred. The divalent aromatic ring group in L₂ includes an arylene group having a carbon number of 6 to 14, which may have a substituent, such as phenylene group, tolylene group and naphthylene group, and a divalent aromatic ring group containing a heterocyclic ring such as thiophene, furan, pyrrole, benzothiophene, benzofuran, benzopyrrole, triazine, imidazole, benzimidazole, triazole, thiadiazole and thiazole.

L₂ is preferably a single bond, an alkylene group, a divalent aliphatic hydrocarbon ring group, a group formed by combining an alkylene group and a divalent aliphatic hydrocarbon ring group, or a group formed by combining an alkylene group and a divalent aromatic ring group, more preferably a single bond, an alkylene group or a divalent aliphatic hydrocarbon ring group, still more preferably a single bond or an alkylene group.

Each of the alkyl groups in R4 to ¾ is independently a linear or branched alkyl group which may have a substituent, and is preferably an alkyl group having a carbon number of 20 or less, which may have a substituent, such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, hexyl group, 2- ethylhexyl group, octyl group and dodecyl group, more preferably an alkyl group having a carbon number of 8 or less, still more preferably an alkyl group having a carbon number of 3 or less.

The monovalent aliphatic hydrocarbon ring group of R₅ or R₆ may be monocyclic or polycyclic. Examples of the cycloalkyl group include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, an adamantyl group, a diadamantyl group, a tetracyclodecanyl group and a tetracyclododecanyl group,. The monovalent aliphatic hydrocarbon ring group preferably has a carbon number of 3 to 20, more preferably a carbon number of 5 to 10.

The ring formed by combining R₅ and R6 with each other is preferably a ring having a carbon number of 3 to 20 and may be a monocyclic ring such as cyclopentyl group and cyclohexyl group, or a polycyclic ring such as norbornyl group, adamantyl group, tetracyclodecanyl group and tetracyclododecanyl group. In the case where R₅ and ^ combine with each other to form a ring, R₄ is preferably an alkyl group having a carbon number of 1 to 3, more preferably a methyl group or an ethyl group.

Specific examples of the structural moiety (SI) are illustrated below. 

In the case where the structural moiety (S2) contains a lactone structure, a 5- to 7-membered ring lactone structure is preferred, and a 5- to 7-membered ring lactone structure to which another ring structure is fused to form a bicyclo structure or a spiro structure is preferred.

Examples of the lactone structure include structures represented by the following formulae (LCl-1) to (LCl-17). Among these, structures represented by (LCl-1), (LCI -4), (LCI -5), (LCI -6), (LCI -13), (LCI -14) and (LCl-17) are preferred, and a structure represented by (LCI -4) is more preferred.

The lactone structure 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 monovalent aliphatic hydrocarbon ring group having a carbon number of 4 to 7, an alkoxy group having a carbon number of 1 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 repeating unit (al) preferably has, for example, a structure represented by the following formula (1):

In formula (1), Li represents a single bond, an alkylene group, an alkenylene group, a divalent aliphatic hydrocarbon ring group, a divalent aromatic ring group, or a group composed of a combination of two or more thereof and when a plurality of Li's are present, each Li may be the same as or different from every other L].

R-3 represents an alkyl group or a monovalent aliphatic hydrocarbon ring group and when a plurality of R₃'s are present, each R₃ may be the same as or different from every other R₃ and the plurality of R₃'s may combine with each other to form a ring.

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

Y represents the structural unit (SI) and when a plurality of Y's are present, each Y may be the same as or different from every other Y.

Zi₂ represents a single bond, -0-, -S-, -CO-, -S0₂-, -NR-, a divalent nitrogen- containing non-aromatic heterocyclic group, or a group composed of a combination thereof and when a plurality of Zi₂'s are present, each Z₁₂ may be the same as or different from every other Z₁₂.

R represents a hydrogen atom or an alkyl group.

k represents an integer of 0 to 5.

m represents an integer of 1 to 5 satisfying the relationship of m+k<6.

n represents an integer of 0 to 5.

As described above, Lj represents a single bond, an alkylene group, an alkenylene group, a divalent aliphatic hydrocarbon ring group, a divalent aromatic ring group, or a group composed of a combination of two or more thereof.

The alkylene group in Li, the alkylene group in L_{1 }} may be linear or branched, and preferred examples thereof include an alkylene group having a carbon number of 1 to 8, such as methylene group, ethylene group, propylene group, butylene group, hexylene group and octylene group. An alkylene group having a carbon number of 1 to 6 is more preferred, and an alkylene group having a carbon number of 1 to 4 is still more preferred.

The alkenylene group of Li includes a group having a double bond at an arbitrary position of the above-described alkylene group except for a methylene group.

The divalent aliphatic hydrocarbon ring group of Lj may be either monocyclic or polycyclic, and preferred examples thereof include a divalent aliphatic hydrocarbon ring group having a carbon number of 3 to 17, such as cyclobutylene group, cyclopentylene group, cyclohexylene group, norbornanylene group, adamantylene group and diamantanylene group. A divalent aliphatic hydrocarbon ring group having a carbon number of 5 to 12 is more preferred, and a divalent aliphatic hydrocarbon ring group having a carbon number of 6 to 10 is still more preferred.

The divalent aromatic ring group of Li includes an arylene group having a carbon number of 6 to 14, which may have a substituent, such as phenylene group, tolylene group and naphthylene group, and a divalent aromatic ring group containing a heterocyclic ring such as thiophene, furan, pyrrole, benzothiophene, benzofuran, benzopyrrole, triazine, imidazole, benzimidazole, triazole, thiadiazole and thiazole.

L_\ is preferably a single bond, a divalent aliphatic hydrocarbon ring group, a group formed by combining a divalent aliphatic hydrocarbon ring group and an alkylene group, a divalent aromatic ring group, or a group formed by combining a divalent aromatic ring group and an alkylene group, more preferably a single bond, a divalent aliphatic hydrocarbon ring group or a divalent aromatic ring group, still more preferably a single bond or a divalent aliphatic hydrocarbon ring group.

As described above, R₃ represents an alkyl group or a monovalent aliphatic hydrocarbon ring group. This alkyl group or monovalent aliphatic hydrocarbon ring group may further have a substituent.

The alkyl group of R₃ preferably has a carbon number of 1 to 30, more preferably a carbon number of 1 to 15. The alkyl group of R₃ may be linear or branched.

Examples of the linear alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-dodecyl group, an n-tetradecyl group and an n-octadecyl group.

Examples of the branched alkyl group include an isopropyl group, an isobutyl group, a tert-butyl group, a neopentyl group and a 2-ethylhexyl group.

The monovalent aliphatic hydrocarbon ring group of R₃ may be monocyclic or polycyclic. Also, a part of carbon atoms in the monovalent aliphatic hydrocarbon ring group of R₃ may be substituted for by a heteroatom such as oxygen atom.

The monovalent aliphatic hydrocarbon ring group of R₃ preferably has a carbon number of 3 to 20. Examples of this monovalent aliphatic hydrocarbon ring group include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group and an adamantyl group.

Examples of the substituent which the alkyl group or monovalent aliphatic hydrocarbon ring group of R₃ may have 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; an alkyl group such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group and hexyl group; a cycloalkyl group such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group and cycloheptyl group; a cyano group; a nitro group, a sulfonyl group; a silyl group; an ester group; an acyl group; a vinyl group; and an aryl group.

Incidentally, when k>2, at least two R₃'s may combine with each other to form a ring. The group formed by combining at least two R₃'s with each other is preferably a cycloalkylene group.

As described above, X represents an alkylene group, an oxygen atom or a sulfur atom. This alkylene group may further have a substituent.

The alkylene group of X is preferably an alkylene group having a carbon number of 1 or 2. That is, the alkylene group of X is preferably a methylene group or an ethylene group.

Examples of the substituent which the alkylene group of X may have include the above-described groups enumerated as the substituent which the alkyl group or monovalent aliphatic hydrocarbon ring group of R₃ may have.

Y represents the structural moiety (SI) and when a plurality of Y's are present, each Y may be the same as or different from every other Y (specific descriptions and preferred examples are also the same).

Specific examples and preferred examples of the alkyl group represented by R in -NR- as Zi₂ are the same as those described for the alkyl group represented by R in -NR- as Z₂i.

Also, specific examples and preferred examples of the divalent nitrogen- containing non-aromatic heterocyclic group as Z[₂ are the same as those described for the divalent nitrogen-containing non-aromatic heterocyclic group as Z₂j.

Zu is preferably a single bond, -0-, -OCO-, -COO-, -OS0₂-, -CONR- or -NRCO-, more preferably a single bond, -0-, -OCO-, -COO- or -CONR-, still more preferably a single bond, -0-, -OCO- or -COO-.

As described above, k represents an integer of 0 to 5. k is preferably an integer of 0 to 3.

As described above, m represents an integer of 1 to 5 satisfying the relationship of m+k<6. m is preferably an integer of 1 to 3, more preferably 1.

n represents an integer of 0 to 5 and may be 0 or may be an integer of 1 to 5. In the former case, the glass transition temperature (Tg) of the resin becomes high and, for example, the exposure latitude can be more enhanced. In the latter case, the solubility of the resin in a developer can be more enhanced, n is preferably an integer of 0 to 3.

The repeating unit (al) is preferably a repeating unit represented by the followin formula (Al):

In formula (Al), each of Rn to Rj₃ independently represents a hydrogen atom, an alkyl group or a halogen atom. Ri₂ may combine with Li to form a ring and the ring may be monocyclic or polycyclic.

Li represents a single bond, an alkylene group, an alkenylene group, a divalent aliphatic hydrocarbon ring group, a divalent aromatic ring group, or a group composed of a combination of two or more thereof and when a plurality of Li's are present, each Li may be the same as or different from every other Li. In the group composed of a combination, two or more groups combined may be the same or different and may be connected through a linking group of -0-, -S-, -CO-, -S0₂-, -NR-, a divalent nitrogen-containing non-aromatic heterocyclic group or a group composed of a combination thereof. R represents a hydrogen atom or an alkyl group.

Here, when a ring is formed together with ]₂, L] represents a trivalent or higher valent group resulting from removing one or more arbitrary hydrogen atoms of a divalent group as Li.

R₃ represents an alkyl group or a monovalent aliphatic hydrocarbon ring group and when a plurality of R₃'s are present, each R₃ may be the same as or different from every other R₃ and the plurality of R₃'s may combine with each other to form a ring.

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

Each of Zn and Z₁₂ independently represents a single bond, -0-, -S-, -CO-, -S0₂-, -NR-, a divalent nitrogen-containing non-aromatic heterocyclic group or a group composed of a combination thereof and when a plurality of Zj₂'s are present, each Zi₂ may be the same as or different from every other Z₁₂. R represents a hydrogen atom or an alkyl group.

k represents an integer of 0 to 5.

m represents an integer of 1 to 5 satisfying the relationship of m+k<6. n represents an integer of 0 to 5.

The alkyl group of Rn to R₁₃ in formula (Al) is preferably an alkyl group having a carbon number of 1 to 5, more preferably a methyl group. The alkyl group of Rn to Ri3 may further have a substituent. Examples of the substituent include a halogen atom, a hydroxy group, and an alkoxy group such as methoxy group, ethoxy group, isopropoxy group, tert-butoxy group and benzyloxy group. Rn is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom, a methyl, group, a hydroxymethyl group or a trifluoromethyl group.

L_1; Z₁₂, R, X, R₃, Y, k, m and n are the same as those described in formula (1) (preferred embodiments are also the same). Specific examples of Zn are the same as specific examples of Zi₂ described in formula (1) (preferred embodiments are also the same).

Zn is preferably a single bond, -COO-, -OCO-, -S0₃-, -CONR-, or a group formed by combining -CO- and a divalent nitrogen-containing non-aromatic heterocyclic group, more preferably a single bond, -COO-, -CONR-, or a group formed by combining -CO- and a divalent nitrogen-containing non-aromatic heterocyclic group, still more preferably -COO- or -CONR-.

The repeating unit (al) is more preferably represented by the following formula (A2):

In formula (A2), Rj 1 represents a hydrogen atom or an alkyl group.

Li represents a single bond, an alkylene group, an alkenylene group, a divalent aliphatic hydrocarbon ring group, a divalent aromatic ring group, or a group composed of a combination of two or more thereof and when a plurality of Li's are present, each Li may be the same as or different from every other Lj.

Each of Zi 1 and Z₁₂ independently represents a single bond, -0-, -S-, -CO-,

-SO₂-, -NR-, a divalent nitrogen-containing non-aromatic heterocyclic group, or a group composed of a combination thereof and when a plurality of Z₁₂'s are present, each Z₁₂ may be the same as or different from every other Zi₂.

R4 represents an alkyl group.

Each of R₅ and R6 independently represents an alkyl group or a monovalent aliphatic hydrocarbon ring group, and R₅ and R^ may combine with each other to form a ring.

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

Z₂i represents a single bond, -0-, -S-, -CO-, -S0₂-, -NR- (R represents a hydrogen atom or an alkyl group), a divalent nitrogen-containing non-aromatic heterocyclic group, or a group composed of a combination thereof.

L₂ represents a single bond, an alkylene group, an alkenylene group, a divalent aliphatic hydrocarbon ring group, a divalent aromatic ring group, or a group composed of a combination of two or more thereof, and in the group composed of a combination, two or more groups combined may be the same or different and may be connected through a linking group of -0-, -S-, -CO-, -S0₂-, -NR-, a divalent nitrogen- containing non-aromatic heterocyclic group or a group composed of a combination thereof.

R represents a hydrogen atom or an alkyl group,

k represents an integer of 0 to 5.

n represents an integer of 0 to 5.

Specific examples and preferred examples of each group in formula (A2) and preferred ranges of k and n are the same as those described in formula (Sl-1), formula (1) and formula (Al).

The resin (A) containing a repeating unit represented by formula (A2) is obtained by polymerizing a compound corresponding to formula (A2) or copolymerizing this compound with another monomer.

The compound corresponding to formula (A2) can be synthesized according to an ordinary method. For example, the polymerizable compound represented by formula (3M) can be synthesized as in the following scheme.

In the scheme above, R₇ is a group providing an alcohol R₇OH having acidity high enough to enable hydrolyzing the carbonic acid ester (-COOR7) moiety of the compound represented by formula (3M-2) with sodium hydroxide, potassium carbonate or the like, and examples of such R₇OH include 1,1, 1,3,3, 3-hexafluoroisopropyl alcohol, 2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenol, and 2,3,4,5,6-pentafluorophenol.

R₈ represents a chlorine atom or a hydroxyl group. In the case where R₈ is a chlorine atom, the polymerizable compound (corresponding to the later-described polymerizable moiety) used for a reaction with the compound represented by formula (3M-2) becomes an acid chloride, and in the case where R₈ is a chlorine atom, the polymerizable compound becomes a carboxylic acid.

In formula (3M), R_Ia has the same meaning as Rn above, and R₃, R4, R5, R₆, X, k and n have the same meanings as those in formula (A2). 1 represents an integer of 1 to 5. In the case where n is an integer of 1 to 5, 1 is preferably 1.

First, the cyanolactone compound represented by the formula above is hydrolyzed to convert the cyano group into a carboxy group, whereby a carboxylic acid represented by formula (3M-1) is obtained.

Next, the carboxylic acid represented by formula (3M-1) is reacted with an alcohol to obtain a compound represented by formula (3M-2).

This reaction is performed, for example, by sequentially or simultaneously adding the carboxylic acid represented by formula (3M-1), an alcohol, a base and a condensing agent in a solvent. At this time, if desired, the reaction system may be cooled or heated. Examples of the solvent for this reaction include tetrahydrofuran, chloroform, dichloroethane, ethyl acetate and acetonitrile. Examples of the base include 4- dimethylaminopyridine. Examples of the condensing agent include Ν,Ν'- dicyclohexylcarbodiimide, l-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, Ν,Ν'-diisopropylcarbodiimide, N-(tert-butyl)-N'-ethylcabodiimide, and N,N'-di(tert-butyl)carbodiimide.

Subsequently, the alcohol represented by formula (3M-2) and a polymerizable moiety are reacted to obtain an ester represented by formula (3M-3). This polymerizable moiety can be easily introduced by a known method.

For example, in the case where the polymerizable moiety is an acid chloride such as methacrylic acid chloride and norbornene carboxylic acid chloride, the reaction above is performed, for example, as follows. That is, the reaction is performed, for example, by sequentially or simultaneously adding the alcohol represented by formula (3M-2), the acid chloride above and a base in a solvent. At this time, if desired, the reaction system may be cooled or heated.

Examples of the solvent for this reaction include tetrahydrofuran, acetonitrile, ethyl acetate, diisopropyl ether and methyl ethyl ketone. Examples of the base include triethylamine, pyridine and 4-dimethylaminopyridine.

In the case where the polymerizable moiety is a carboxylic acid such as methacrylic acid and norbornene carboxylic acid, the reaction above is performed, for example, as follows. That is, the reaction is performed, for example, by mixing the alcohol represented by formula (3M-2), the above-described carboxylic acid and an inorganic acid and/or an organic acid and heating the mixture. The reaction may be performed while removing water produced by the reaction to the outside of the system.

Examples of the solvent for this reaction include toluene and hexane. Examples of the inorganic acid include hydrochloric acid, sulfuric acid, nitric acid and perchloric acid. Examples of the organic acid include p-toluenesulfonic acid and benzenesulfonic acid.

Thereafter, the ester represented by formula (3M-3) is hydrolyzed. In this way, the carboxylic acid represented by formula (3M-4) is obtained.

This hydrolysis reaction is performed, for example, by sequentially or simultaneously adding the ester represented by formula (3M-3) and a base in a solvent. At this time, if desired, the reaction system may be cooled or heated.

Examples of the solvent for this reaction include acetone, tetrahydrofuran, acetonitrile and water. Examples of the base include sodium hydroxide and potassium carbonate.

Furthermore, the acid moiety of the carboxylic acid represented by formula (3M-4) is converted into an acid chloride to obtain an acid chloride represented by formula (3M-5). This reaction is performed, for example, by sequentially or simultaneously adding the carboxylic acid represented by formula (3M-4) and thionyl chloride. At this time, if desired, the reaction system may be cooled or heated. Also, a solvent such as benzene and dichloromethane, and/or a catalyst such as dimethylformamide, hexamethylphosphoric acid triamide and pyridine may be further added.

Finally, the acid chloride represented by formula (3M-5) and a corresponding alcohol are reacted to obtain the compound represented by formula (3M). This reaction of the acid chloride and an alcohol can be performed in the same manner as the above-described synthesis of the compound represented by formula (3M-3).

The content of the repeating unit (al) is preferably from 15 to 100 mol%, more preferably from 20 to 100 mol%, still more preferably from 30 to 100 mol%, based on all repeating units in the resin (A).

Specific examples of the repeating unit (al) are illustrated below. In specific examples, R_\ represents a hydrogen atom, an alkyl group which may have a substituent, or a halogen atom. R_\ is preferably a hydrogen atom, a methyl group, a hydroxymethyl group, a trifluoromethyl group or a fluorine atom.

31

33

[Repeating Unit (a2)]

The resin (A) may contain (a2) a repeating unit capable of decomposing by the action of an acid to generate an alkali-soluble group (hereinafter sometimes referred to as an "acid-decomposable group-containing repeating unit"), which is different from the repeating unit (al).

Specific examples and preferred examples of the alkali-soluble group are the same as those of the alkali-soluble group described above for the acid-decomposable group of the repeating unit (al).

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

Specific examples and preferred examples of the group capable of leaving by the action of an acid are the same as those described above in the acid-decomposable group suitably contained in the structural moiety (SI). The repeating unit (a2) is preferably a repeating unit represented by the following formul

In formula (V), each of R₅i, R₅₂ and R₅₃ independently represents a hydrogen atom, an alkyl group, a monovalent aliphatic hydrocarbon ring group, a halogen atom, a cyano group or an alkoxycarbonyl group. R₅₂ may combine with L₅ to form a ring (preferably a 5- or 6-membered ring). In this case, R₅₂ is preferably an alkylene group. The ring formed by combining Rs₂ and L₅ may be monocyclic or polycyclic.

L5 represents a single bond or a divalent linking group, and in the case of forming a ring with R₅₂, L₅ represents a trivalent or higher valent linking group.

R₅₄ represents an alkyl group, and each of R₅₅ and R₅₆ independently represents a hydrogen atom, an alkyl group, a monovalent aliphatic hydrocarbon ring group or a monovalent aromatic ring group. R₅₅ and R₅₆ may combine with each other to form a ring. However, R55 and R₅₆ are not a hydrogen atom at the same time.

Formula (V) is described in more detail.

The alkyl group of R₅₁ to R₅₃ in formula (V) is preferably an alkyl group having a carbon number of 20 or less, such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, hexyl group, 2-ethylhexyl group, octyl group and dodecyl group, which may have a substituent, more preferably an alkyl group having a carbon number of 8 or less, still more preferably an alkyl group having a carbon number of 3 or less.

As for the alkyl group contained in the alkoxycarbonyl group, the same alkyl group as in R51 to R₅₃ is preferred.

The monovalent aliphatic hydrocarbon ring group may be monocyclic or polycyclic and is preferably a monocyclic monovalent aliphatic hydrocarbon ring group having a carbon number of 3 to 8, such as cyclopropyl group, cyclopentyl group and cyclohexyl group, which may have a substituent. The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, with a fluorine atom being preferred.

Preferred examples of the substituent in each of the groups above include an alkyl group, a monovalent aliphatic hydrocarbon ring group, an aryl group, an amino group, an amido group, an ureido group, a urethane group, a hydroxyl group, a carboxyl group, a halogen atom, an alkoxy group, a thioether group, an acyl group, an acyloxy group, an alkoxycarbonyl group, a cyano group and a nitro group, and the carbon number of the substituent is preferably 8 or less.

In the case where R₅₂ is an alkylene group and forms a ring with L₅, the alkylene group is preferably an alkylene group having a carbon number of 1 to 8, such as methylene group, ethylene group, propylene group, butylene group, hexylene group and octylene group, more preferably an alkylene group having a carbon number of 1 to 4, still more preferably an alkylene group having a carbon number of 1 or 2.

Each of R51 and R₅₃ in formula (V) is preferably a hydrogen atom, an alkyl group or a halogen atom, more preferably a hydrogen atom, a methyl group, an ethyl group, a trifluoromethyl group (-CF₃), a hydroxymethyl group (-CH₂-OH), a chloromethyl group (-CH₂-C1) or a fluorine atom (-F). R₅₂ is preferably a hydrogen atom, an alkyl group, a halogen atom or an alkylene group (forms a ring with L₅), more preferably a hydrogen atom, a methyl group, an ethyl group, a trifluoromethyl group (-CF₃), a hydroxymethyl group (-CH₂-OH), a chloromethyl group (-CH₂-C1), a fluorine atom (-F), a methylene group (forms a ring with L₅) or an ethylene group (forms a ring

Examples of the divalent linking group represented by L₅ include an alkylene group, a divalent aromatic ring group, -COO-L1 -, -O-L1 -, and a group formed by combining two or more of these groups. L] represents an alkylene group, a divalent aliphatic hydrocarbon group, a divalent aromatic ring group, and a group formed by combining an alkylene group and a divalent aromatic ring group.

Specific examples of the trivalent or higher valent linking group represented by L₅ when forming a ring by L₅ and R₅₂ include groups formed by removing one or more arbitrary hydrogen atoms from specific examples above of the divalent linking group.

L₅ is preferably a single bond, a group represented by -COO-Li- (Li is preferably an alkylene group having a carbon number of 1 to 5, more preferably a methylene group or a propylene group), or a divalent aromatic ring group. In the case of performing the exposure by an ArF excimer laser, from the standpoint of decreasing absorption in the 193 nm region, L₅ is preferably a single bond or -COO-Lj- (L] is preferably an alkylene group having a carbon number of 1 to 5, more preferably a methylene group or a propylene group).

The alkyl group of R₅₄ to R₅₆ is preferably an alkyl group having a carbon number of 1 to 20, 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 4, such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl and tert- butyl group.

The monovalent aliphatic hydrocarbon ring group represented by R₅₅ and R₅₆ is preferably an aliphatic hydrocarbon ring group having a carbon number of 3 to 20 and may be a monocyclic hydrocarbon ring group such as cyclopentyl group and cyclohexyl group, or a polycyclic hydrocarbon ring group such as norbornyl group, adamantyl group, tetracyclodecanyl group and tetracyclododecanyl group.

The ring formed by combining R₅₅ and R₅₆ with each other is preferably a ring having a carbon number of 3 to 20 and may be a monocyclic ring such as cyclopentyl group and cyclohexyl group, or a polycyclic ring such as norbornyl group, adamantyl group, tetracyclodecanyl group and tetracyclododecanyl group. In the case where R₅₅ and R₅₆ combine with each other to form a ring, R₅₄ is preferably an alkyl group having a carbon number of 1 to 3, more preferably a methyl group or an ethyl group.

The monovalent aromatic ring group represented by R₅₅ and R₅₆ is preferably an aromatic ring group having a carbon number of 6 to 20, and examples thereof include a phenyl group and a naphthyl group. In the case where either one of R₅₅ and R₅₆ is a hydrogen atom, the other is preferably a monovalent aromatic ring group.

In the case of performing the exposure by an ArF excimer laser, from the standpoint of decreasing absorption in the 193 nm region, each of R55 and R₅₆ is independently, preferably a hydrogen atom, an alkyl group or a monovalent aliphatic hydrocarbon ring group.

The synthesis method of the monomer corresponding to the repeating unit represented by formula (V) is not particularly limited, and synthesis methods for a general polymerizable group-containing ester are applicable.

Specific examples of the repeating unit (a2) 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 polar group-containing substituent, and the polar group-containing substituent is, for example, a hydroxyl group, a cyano group, an amino group, an alkylamide or sulfonamide group itself, or a linear or branched alkyl group or cycloalkyl group having at least one of these groups, preferably a hydroxyl group-containing alkyl group, more preferably a hydroxyl group-containing branched alkyl group. The branched alkyl group is preferably an isopropyl group, p represents 0 or a positive integer, and when p>2, each Z may be the same as or different from every other Z.

The resin (A) for use in the present invention may or may not contain the repeating unit (a2) but in the case of containing the repeating unit (a2), the content thereof is preferably from 1 to 70 mol%, more preferably from 5 to 60 mol%, still more preferably from 10 to 50 mol%, based on all repeating units in the resin (A).

[Repeating Unit (a3)]

The resin (A) may contain (a3) a repeating unit having a group capable of decomposing by the action of an alkali developer to increase the dissolution rate in an alkali developer, which is different from the repeating unit (al).

Examples of the group capable of decomposing by the action of an alkali developer to increase the dissolution rate in an alkali developer include a lactone structure and a phenyl ester structure.

The repeating unit (a3) is preferably a repeating unit represented by the following formula (All):

In formula (All), Rb₀ represents a hydrogen atom, a halogen atom or an alkyl group (preferably having a carbon number of 1 to 4) which may have a substituent.

Preferred substituents which the alkyl group of Rb₀ may have include a hydroxyl group and a halogen atom. The halogen atom of Rb₀ 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.

Ab represents a single bond, an alkylene group, a divalent linking group having a monocyclic or polycyclic aliphatic hydrocarbon ring structure, an ether group, an ester group, a carbonyl group, or a divalent linking group formed by combining these, and is preferably a single bond or a divalent linking group represented by -Ab₁-C0₂-.

Abi represents a linear or branched alkylene group or a monocyclic or polycyclic aliphatic hydrocarbon ring group and is preferably a methylene group, an ethylene group, a cyclohexylene group, an adamantylene group or a norbomylene group.

V represents a group capable of decomposing by the action of an alkali developer to increase the dissolution rate in an alkali developer and is preferably a group having an ester bond, more preferably a group having a lactone structure.

As for the group having a lactone structure, any group may be used as long as it has a lactone structure, but a 5- to 7-membered ring lactone structure is preferred, and a 5- to 7-membered ring lactone structure to which another ring structure is fused to form a bicyclo structure or a spiro structure is preferred. V is more preferably a group having a lactone structure represented by any of formulae (LCl-1) to (LCI -17). Also, the resin (A) may further contain, other than the repeating unit (a3), a repeating unit where a lactone structure is bonded directly to the main chain. Preferred lactone structures are (LCl-1), (LCI -4), (LCl-5), (LCI -6), (LCl-13) and (LCl-14). By using a specific lactone structure, the line width roughness performance and development defect are improved.

The repeating unit containing a group having a lactone structure 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 resin (A) for use in the present invention may not contain the repeating unit (a3), but in the case of containing the repeating unit (a3), the content thereof is preferably from 1 to 60 mol%, more preferably from 2 to 50 mol%, still more preferably from 5 to 50 mol%, based on all repeating units in the resin (A). As for the repeating unit (a3), one kind may be used, or two or more kinds may be used in combination.

Specific examples of the repeating unit (a3) in the resin (A) are illustrated below, but the present invention is not limited thereto. In formulae, Rx is H, CH₃, CH₂OH or CF₃.

[Repeating Unit (a4)]

The resin (A) may contain (a4) a repeating unit having a hydroxyl group or a cyano group, other than the repeating unit (al), repeating unit (a2) and repeating unit (a3). Thanks to this repeating unit, the adherence to substrate and the affinity for developer are enhanced.

The repeating unit (a4) is preferably a repeating unit having an ahcyclic hydrocarbon structure substituted with a hydroxyl group or a cyano group and is preferably free from an 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 norbornane 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 I » ) (V I I b ) (V I I c ) (V ! I d)

In formulae (Vila) to (VIIc), each of R₂c to R4C independently represents a hydrogen atom, a hydroxyl group or a cyano group, provided that 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 R C 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 R4C have the same meanings as R₂c to R4C in formulae (Vila) to (VIIc).

The resin (A) for use in the present invention may not containing the repeating unit (a4) but in the case of containing the repeating unit (a4), the content thereof is preferably from 1 to 40 mol%, more preferably from 2 to 30 mol%, still more preferably from 5 to 25 mol%, based on all repeating units in the resin (A).

Specific examples of the repeating unit having a hydroxyl group or a cyano group are illustrated below, but the present invention is not limited thereto.

The resin (A) for use in the present invention may contain a repeating unit having an alkali-soluble group. The alkali-soluble group includes a phenolic hydroxyl group, a carboxyl group, a sulfonamide group, a sulfonylimide group, a bisulfonylimide group, and an aliphatic alcohol substituted with an electron-withdrawing group at the exposition (for example, hexafluoroisopropanol group).

In the case of performing the exposure by an ArF excimer laser, the resin preferably contains 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 resin (A) for use in the present invention may not contain the repeating unit having an alkali-soluble group, but in the case containing the repeating unit, the content thereof is preferably from 1 to 20 mol%, more preferably from 1 to 15 mol%, still more preferably from 1 to 10 mol%, based on all repeating units in the resin (A).

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

The resin (A) for use in the present invention may further contain a repeating unit having an alicyclic hydrocarbon structure free from a polar group (such as the above-described alkali-soluble group, hydroxyl group and cyano group) and not exhibiting acid decomposability. Such a repeating unit includes a repeating unit represented by formula (VII):

In formula (VII), R₅ represents a hydrocarbon group having at least one alicyclic hydrocarbon structure and having neither a hydroxyl group nor a cyano 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 alicyclic hydrocarbon structure 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-assembled hydrocarbon group and a crosslinked cyclic hydrocarbon group. Examples of the ring-assembled 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[4.3.1.1²'⁵]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

2 6

tricyclo[5,2,l ,0 ' ]decanyl group. As for the crosslinked cyclic hydrocarbon ring, a norbornyl group and an adamantyl group are more preferred.

Such an alicyclic hydrocarbon group may have a substituent, and preferred examples of the substituent include a halogen atom, an alkyl group, a hydroxyl group with a hydrogen atom being substituted for, and an amino group with a hydrogen atom being substituted for. 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 with a hydrogen atom being substituted for, and an amino group with a hydrogen atom being substituted for.

Examples of the substituent for the hydrogen atom include an alkyl group, a monovalent aliphatic hydrocarbon ring group, an aralkyl group, a substituted methyl group, a substituted ethyl 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 preferably an alkoxycarbonyl group having a carbon number of 1 to 4.

The resin (A) for use in the present invention may not contain a repeating unit having an alicyclic hydrocarbon structure free from a polar group and not exhibiting acid decomposability, but in the case of this repeating unit, the content thereof is preferably from 1 to 40 mol%, more preferably from 5 to 20 mol%, based on all repeating units in the resin (A).

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

H, CH₃, CH₂OH or CF₃.

The resin (A) for use in 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 such a repeating structural unit, the performance required of the resin used in the composition of the present invention, particularly

(1) solubility in the coating solvent,

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

(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 this 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 (A) for use in the composition of the present invention, the molar ratio of respective repeating structural units contained is appropriately determined 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 resist composition for organic solvent-type development of the present invention is used for ArF exposure, in view of transparency to ArF light, the resin (A) preferably has substantially no aromatic group (specifically, the ratio of an aromatic group-containing repeating unit in the resin is preferably 5 mol% or less, more preferably 3 mol% or less, and ideally 0 mol%, that is, the resin does not have an aromatic group), and the resin (A) preferably has a monocyclic or polycyclic alicyclic hydrocarbon structure.

Also, in the case where the composition of the present invention contains a resin (B) described later, the resin (A) preferably contains no fluorine atom and no silicon atom in view of compatibility with the resin (B).

The form of the resin (A) for use in the present invention may be any of random type, block type, comb type and star type.

The resin (A) can be synthesized, for example, by radical, cationic or anionic polymerization of unsaturated monomers corresponding to respective structures. The resin may also be synthesized by polymerizing unsaturated monomers corresponding to precursors of respective structures and then performing a polymer reaction.

Examples of the general synthesis method include a batch polymerization method of dissolving unsaturated monomers and a polymerization initiator in a solvent and heating the solution, thereby effecting the polymerization, and a dropping polymerization method of adding dropwise a solution containing unsaturated monomers and a polymerization initiator to a heated solvent over 1 to 10 hours. A dropping polymerization method is preferred.

As to the solvent used for the polymerization, examples of the reaction solvent include tetrahydrofuran, 1,4-dioxane, ethers such as diisopropyl ether, ketones such as methyl ethyl ketone and methyl isobutyl ketone, an ester solvent such as ethyl acetate, an amide solvent such as dimethylformamide and dimethylacetamide, and the later-described solvent usable at the preparation of the actinic ray-sensitive or radiation- sensitive resin composition, such as propylene glycol monomethyl ether acetate (PGMEA; another name: l-methoxy-2-acetoxypropane), propylene glycol monomethyl ether (PGME; another name: 1 -methoxy-2-propanol) and cyclohexanone. The polymerization is more preferably performed using the same solvent as the solvent used in the composition of the present invention. By the use of this 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). If desired, the polymerization may be performed in the presence of a chain transfer agent (e.g., alkylmercaptan).

The concentration of the solute in the reaction solution is usually from 5 to 70 mass%, preferably from 10 to 50 mass%, and the reaction temperature is usually from 10 to 150°C, preferably from 30 to 120°C, more preferably from 40 to 100°C.

The reaction time is usually from 1 to 48 hours, preferably from 1 to 24 hours, more preferably from 1 to 12 hours.

After the completion of reaction, the reaction solution is allowed to cool to room temperature and purified. The purification may be performed by a normal method, and examples of the applicable method include a liquid-liquid extraction method of performing water washing or combining an appropriate solvent to remove residual monomers or oligomer components; a purification method in a solution sate, such as ultrafiltration of removing by extraction only those having a molecular weight not more than a specific value; a reprecipitation method of adding dropwise a resin solution in a poor solvent to solidify the resin in the poor solvent and thereby remove residual monomers and the like; and a purification method in a solid state, such as a method of subjecting a resin slurry separated by filtration to washing with a poor solvent. For example, the resin is precipitated as a solid by contacting the reaction solution with a solvent in which the resin is sparingly soluble or insoluble (poor solvent) and which is in a volumetric amount of 10 times or less, preferably from 10 to 5 times, the reaction solution.

The solvent used at the operation of precipitation or reprecipitation from the polymer solution (precipitation or reprecipitation solvent) may be sufficient if it is a poor solvent to the polymer, and the solvent which can be used may be appropriately selected from a hydrocarbon, a halogenated hydrocarbon, a nitro compound, an ether, a ketone, an ester, a carbonate, an alcohol, a carboxylic acid, water, a mixed solvent containing such a solvent, and the like, according to the kind of the polymer. Among these solvents, a solvent containing at least an alcohol (particularly, methanol or the like) or water is preferred as the precipitation or reprecipitation solvent.

The amount of the precipitation or reprecipitation solvent used may be appropriately selected by taking into consideration the efficiency, yield and the like, but in general, the amount used is from 100 to 10,000 parts by mass, preferably from 200 to 2,000 parts by mass, more preferably from 300 to 1,000 parts by mass, per 100 parts by mass of the polymer solution.

The temperature at the precipitation or reprecipitation may be appropriately selected by taking into consideration the efficiency or operability but is usually on the order of 0 to 50°C, preferably in the vicinity of room temperature (for example, approximately from 20 to 35°C). The precipitation or reprecipitation operation may be performed using a commonly employed mixing vessel such as stirring tank, by a known method such as batch system and continuous system.

The precipitated or reprecipitated polymer is usually subjected to commonly employed solid-liquid separation such as filtration and centrifugation, then dried and used. The filtration is performed using a solvent-resistant filter element preferably under pressure. The drying is performed under atmospheric pressure or reduced pressure (preferably under reduced pressure) at a temperature of approximately from 30 to 100°C, preferably on the order of 30 to 50°C.

Incidentally, after the resin is once precipitated and separated, the resin may be again dissolved in a solvent and then put into contact with a solvent in which the resin is sparingly soluble or insoluble. That is, there may be used a method comprising, after the completion of radical polymerization reaction, bringing the polymer into contact with a solvent in which the polymer is sparingly soluble or insoluble, to precipitate a resin (step a), separating the resin from the solution (step b), anew dissolving the resin in a solvent to prepare a resin solution A (step c), bringing the resin solution A into contact with a solvent in which the resin is sparingly soluble or insoluble and which is in a volumetric amount of less than 10 times (preferably 5 times or less) the resin solution A, to precipitate a resin solid (step d), and separating the precipitated resin (step e).

The molecular weight of the resin (A) for use in the present invention is not particularly limited, but the weight average molecular weight is preferably from 1 ,000 to 200,000, more preferably from 2,000 to 60,000, still more preferably from 2,000 to 30,000. 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 successfully 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. Here, the weight average molecular weight of the resin indicates a molecular weight in terms of polystyrene measured by GPC (carrier: tetrahydrofuran (THF)).

The polydispersity (Mw/Mn) is preferably from 1.00 to 5.00, more preferably from 1.03 to 3.50, more preferably from 1.05 to 2.50. 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.

As for the resin (A) used in the present invention, a single kind of a resin may be used alone, or two or more kinds of resins may be used in combination. The content of the resin (A) is preferably from 30 to 99 mass%, more preferably from 50 to 95 mass%, still more preferably from 70 to 90 mass%, based on the entire solid content in the actinic ray-sensitive or radiation-sensitive resin composition of the present invention.

More preferred specific examples of the resin (A) are illustrated below, but the present invention is not limited thereto. In specific examples, Ra is a hydrogen atom, a methyl group, a hydroxymethyl group, a trifluoromethyl group or a fluorine atom.

54

[2] Resin (Β)

The resin (Β) contains at least either a fluorine atom or a silicon atom.

At least either a fluorine atom or a silicon atom in the resin (B) may be contained in the main chain of the resin or contained in the side chain.

In the case of containing a fluorine atom, the resin (B) is preferably a resin containing a fluorine atom-containing alkyl group, a fluorine atom-containing cycloalkyl group or a fluorine atom-containing aryl group, as the fluorine atom- containing partial structure.

The fluorine atom-containing alkyl group is a linear or branched alkyl group with at least one hydrogen atom being substituted for by a fluorine atom, preferably having a carbon number of 1 to 10, more preferably from 1 to 4, and may further have other substituents.

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

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

Preferred examples of the fluorine atom-containing alkyl group, fluorine atom-containing cycloalkyl group and fluorine atom-containing aryl group include the groups represented by 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 R6₈ independently represents a hydrogen atom, a fluorine atom or an alkyl group (linear or branched). However, at least one of R57 to

represents a fluorine atom or an alkyl group (preferably having a carbon number of 1 to 4) with at least one hydrogen atom being substituted for by a fluorine atom.

It is preferred that all of R₅₇ to R₆i and all of R^₅ to R<s7 are a fluorine atom. Each of R₆2, R03 and R^ 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 R₆₂ and R₆₃ are a perfluoroalkyl group, R64 is preferably a hydrogen atom. R62 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 atom-containing partial structure may be bonded directly 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 of these groups and bonds.

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 Rio 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 resin (B) may contain a unit shown below as the repeating unit having a fluorine atom.

(C-II) (c-in)

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 R4 to R₇ represents a fluorine atom. R4 and R₅, or and R₇ may form a ring.

W₂ represents an organic group having at least one fluorine atom. Specific examples thereof includes 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 a polycyclic structure, the structure may be a crosslinked structure. 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. A part of carbon atoms in the cycloalkyl group may be substituted with a heteroatom such as oxygen atom. In particular, Q is preferably a norbornyl group, a tricyclodecanyl group, a tetracyclododecyl group or the like.

The resin (B) may contain a silicon atom.

The resin preferably has, as the silicon atom-containing partial structure, an alkylsilyl structure (preferably a trialkylsilyl group) or a cyclic siloxane structure.

Specific examples of the alkylsilyl structure and cyclic siloxane structure include the 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, -C¾, -F or -CF₃, and X₂ represents -F or -CF₃.

The resin (B) preferably contains (b) a repeating unit having at least one group selected from the group consisting of 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 in an alkali developer (hereinafter also referred to as "polarity converting group"), and

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) above, on one side chain,

• (b*) a repeating unit having at least one group selected from the group consisting of (x) to (z) above and 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 resin (B) 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 resin (B) 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 like 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. B1

( l )

B2

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)methylene 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 polymer chain terminal 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 (b¹) 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 resin (B).

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 (-S0₂O), 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 (b¹) or (b")). The resin containing the repeating unit (by) has hydrophobicity, and this is preferred particularly in view of reducing the development defect.

The repeating unit (by) includes, for example, a repeating unit represented by formula (K0): (Κ0)

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.

Rk2 represents an alkyl group, a cycloalkyl group, an aryl group or a polarity converting group-containing group.

However, at least either one of R_ki and Ri^ represents a polarity converting group-containing group.

The polarity converting group indicates, 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 (KA-1) or (KB-1):

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-.

Incidentally, the repeating unit (by) contains a group having a partial structure represented by formula (KA-1) or (KB-1) and thereby has a preferred group capable of increasing the solubility in an alkali developer, and as in the case of the partial structure represented by formula (KA-1) or the partial structure represented by formula (KB-1)

1 2

where Y and Y 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 resin (B) 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 Zkai .

Zkai 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.

Zkai's may combine with each other to form a ring. Examples of the ring formed by combining Z^i'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 or the like. 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 a crosslinked cycloalkyl group. 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. The polycyclic cycloalkyl group includes a group having a bicyclo, tricyclo or tetracyclo structure or the like and having a carbon number of 5 or more, and a cycloalkyl group having a carbon number of 6 to 20 is preferred. Examples thereof include an adamantyl group, a norbornyl group, an isoboronyl group, a camphanyl group, a dicyclopentyl group, an a-pinel group, a tricyclodecanyl group, a tetracyclododecyl group and an androstanyl group. As the cycloalkyl group, structures shown below are also preferred. Incidentally, a part of carbon atoms in the cycloalkyl group may be substituted for by a heteroatom such as oxygen atom.

The preferred alicyclic moiety includes 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 and a cyclododecanyl group. 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 and a tricyclodecanyl group are more preferred.

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, cinnamyl group and valeryl group, an acyloxy group such as butyryloxy group, the above-described alkenyl group, an alkenyloxy group such as vinyloxy group, propenyloxy group, allyloxy group and butenyloxy group, the above- described aryl group, an aryloxy group such as phenoxy group, and an aryloxycarbonyl group such as benzoyloxy group.

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

Incidentally, it is preferred that as in (KA-1-1) to (KA-1-17) shown below, another ring structure is condensed to a 5- to 7-membered lactone ring as 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 a 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), (KA-1 -4), (KA-1 -5), (KA-1 -6), (KA-1 -13), (KA-1- 14) and (KA-l-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 Zk_ai 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 Y and Y 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), ne_W is a repetition number of the linking group represented by -C(Rewi)(Re_w2)- and represents an integer of 0 or 1. In the case where ne_W is 0, this indicates bonding by a single bond and direct bonding of Y_ewi .

Yewi is a halogen atom, a cyano group, a nitrile group, a nitro group, a halo(cyclo)alkyl or haloaryl group represented by -C(Rf])(Rf2)-Ro, 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. The term "haloaryl group" indicates an aryl group that is at least partially halogenated. In the structural formulae below, each of Re_w3 and Re_W4 independently represents an arbitrary structure. The partial structure represented by formula (EW) has an electron-withdrawing property irrespective of structures of Re_W3 and Re_w4 and may combine with, for example, 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, Rewi and Re_W2 niay combine with the main chain of the resin (C) through a further substituent.

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

Each of Rewi and Re_w2 independently represents an arbitrary substituent, for example, represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group.

At least two members out of Re_Wl, Rew2 and Y_ewi may combine with each other to form a ring. Rfi 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 trifiuoromethyl group.

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

Rfi 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 Rfi to Rf3 include the alkyl groups in Zkai and halogenated structures thereof.

Examples of the (per)halocycloalkyl group and (per)haloaryl group in Rn to Ro or in the ring formed by combining Rf2 and Rfi include structures resulting from halogenation of cycloalkyl groups in Zkai , and a fluoroalkyl group represented by -C(n₎F(2n-2₎H and a perfluoroaryl group represented by -C_(n)F_(n.j₎ are preferred, where 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 Rewi , Rew2 and Y_ewi 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 represented by formula (KA-1) and a partial structure represented by formula (KB-1).

Here, the partial structure of formula (KA-1) may partially or entirely serve also as the electron- withdrawing group of Y or Y 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 the electron- withdrawing group of Y¹ or Y² 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 shown below.

In formula (bb), Zi 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 Zi's are present each Zi may be the same as or different from every other Zi. Zi is preferably an ester bond.

Z₂ represents a chain or cyclic alkylene group and when a plurality of Z₂'s are present each Z₂ may be the same as or different from every other Z₂. Z₂ is preferably an alkylene group having a carbon number of 1 or 2 or a cycloalkylene group having a carbon number of 5 to 10.

Each Ta independently represents an alkyl group, a cycloalkyl group, an alkoxy group, a nitrile group, a hydroxyl group, an amide group, an aryl group or an electron-withdrawing group (having the same meaning as the electron-withdrawing

I 2

group of Y and Y in formula (KB-1)) and is preferably an alkyl group, a cycloalkyl group or an electron-withdrawing group, more preferably an electron-withdrawing group. When a plurality of Ta's are present, Ta's may combine with each other to form a ring.

L₀ represents a single bond or an (m+l)-valent hydrocarbon group (preferably having a carbon number of 20 or less) and is preferably a single bond. The single bond as L₀ occurs when m is 1. The (m+l)-valent hydrocarbon group as L₀ represents an (m+l)-valent hydrocarbon group formed by removing m-1 arbitrary hydrogen atoms from, for example, an alkylene group, a cycloalkylene group, a phenylene group or a combination thereof. Each L independently represents a carbonyl group, a carbonyloxy group or an ether group.

Tc represents a hydrogen atom, an alkyl group, a cycloalkyl group, a nitrile group, a hydroxyl group, an amide group, an aryl group or an electron-withdrawing group (having the same meaning as the electron-withdrawing group of Y¹ and Y² in formula (KB-1)).

* represents a bond to the main or side chain of the resin. That is, a partial structure represented by formula (bb) may be directly bonded to the main chain, or a partial structure represented by formula (bb) may be bonded to the side chain of the resin. Incidentally, the bond to the main chain is a bond to an atom present in bonds constituting the main chain, and the bond to the side chain is a bond to an atom present in the portion other than the bonds constituting the main chain.

m represents an integer of 1 to 28 and is preferably an integer of 1 to 3, more preferably 1.

k represents an integer of 0 to 2 and is preferably 1.

q is a repetition number of the group (Z2-Z1) and represents an integer of 0 to 5, preferably from 0 to 2.

r represents an integer of 0 to 5.

Incidentally, -L₀-(Ta)_m may be substituted in place of -(L)_r-Tc.

It is also preferred to have a fluorine atom at the terminal of sugar lactone or have a fluorine atom on a side chain different from the side chain on the sugar lactone side in the same repeating unit (this case comes under the repeating unit (b")).

The chain alkylene group as Z₂ has, in the case of a linear alkylene group, a carbon number of preferably from 1 to 30, more preferably from 1 to 20, and in the case of a branched alkylene group, a carbon number of preferably from 3 to 30, more preferably from 3 to 20. Specific examples of the chain alkylene group as R₂ include groups formed by removing one arbitrary hydrogen atom from specific examples of the alkyl group as Z_kai-

The cyclic alkylene group as Z₂ is preferably an alkylene group having a carbon number of 3 to 8, and specific examples thereof include groups formed by removing one arbitrary hydrogen atom from the cycloalkyl group as Z_kal.

The preferred carbon number and specific examples of the alkyl group and cycloalkyl group as Ta and Tc are the same as those described for the alkyl group and cycloalkyl group as Z_kai-

The alkoxy group as Ta is preferably an alkoxy group having a carbon number of 1 to 8, and examples thereof include a methoxy group, an ethoxy group, a propoxy group and a butoxy group.

The aryl group as Ta and Tc is preferably an aryl group having a carbon number of 6 to 12, and examples thereof include a phenyl group and a naphthyl group.

The preferred carbon number and specific examples of the alkylene group and cycloalkylene group as L₀ are the same as those described for the chain alkylene group and cyclic alkylene group as Z₂.

As for the more specific structure of the repeating unit (bb), a repeating unit having a partial structure shown below is preferred.

In formulae (ba-2) and (bb-2), n represents an integer of 0 to 11 and is preferably an integer of 0 to 5, more preferably 1 or 2.

p represents an integer of 0 to 5 and is preferably an integer of 0 to 3, more preferably 1 or 2.

Each Tb independently represents an alkyl group, a cycloalkyl group, an alkoxy group, a nitrile group, a hydroxyl group, an amide group, an aryl group or an electron-withdrawing group (having the same meaning as the electron-withdrawing group of Y and Y in formula (KB-1)) and is preferably an alkyl group, a cycloalkyl group or an electron-withdrawing group. When a plurality of Tb's are present, Tb's may combine with each other to form a ring.

* represents a bond to the main or side chain of the resin. That is, a partial structure represented by formula (ba-2) or (bb-2) may be directly bonded to the main chain, or a partial structure represented by formula (ba-2) or (bb-2) may be bonded to the side chain of the resin.

Z), Z₂, Ta, Tc, L, *, m, q and r have the same meaning as those in formula (bb), and preferred examples are also the same.

The repeating unit (by) may be a repeating unit having a partial structure

In formula (ΚΥ-0), R represents a chain or cyclic alkylene group and when a plurality of R₂'s are present, each R₂ may be the same as or different from every other R₂.

R₃ represents a linear, branched or cyclic hydrocarbon group where a part or all of hydrogen atoms on the constituent carbons are substituted for 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 R4's are present, each R4 may be the same as or different from every other R4, 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 every 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 range of carbon number 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 Zkai -

The preferred carbon numbers and specific examples of the alkyl group and cycloalkyl group as R₄ and R are the same as those described for the alkyl group and cycloalkyl group of Z^i -

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 include 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 for the alkyl group and cycloalkyl group of Zkai -

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 of R₂.

The specific structure of the repeating unit (by) also includes a repeating unit 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, 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 the electron-withdrawing groups as Y¹ and Y². X is preferably 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 or a nitro group.

* 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 resin composition 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 resin composition 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 above-described receding contact angle of the film after alkali development is the contact angle when the following film is measured by an expansion/contraction method described in Examples later. That is, an organic antireflection film, ARC29A (produced by Nissan Chemical Industries, Ltd.), is coated on a silicon wafer (8 inches in diameter) and baked at 205°C for 60 seconds to form a 98 nm-thick antireflection film, the composition of the present invention is coated thereon and baked at 120°C for 60 seconds to form a 120 nm-thick film, this film is developed with an aqueous tetramethylammonium hydroxide solution (2.38 mass%) for 30 seconds, rinsed with pure water and spin-dried, and the contact angle of the obtained film is measured by the expansion/contraction method.

The hydrolysis rate of the resin (B) 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 resin (B) for an alkali developer as used herein is the rate at which the thickness of a resin film formed only of the resin (B) decreases when treated with TMAH (an aqueous tetramethylammonium 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 higher valent group formed by removing at least one arbitrary hydrogen atom in the structure.

In formula (KY-1), each of R_kyi and R_ky4 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, R_kyi and R_ky4 may be bonded to the same atom to form a double bond. For example, _kyi and R_ky4 may be bonded to the same oxygen atom to form a part (=0) of a carbonyl group.

Each of R_ky2 and R_ky3 independently represents an electron-withdrawing group, or while R_kyi and R_ky2 combine to form a lactone ring, R_ky3 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 are the same as those for Yj and Y₂ in formula (KB-1), and a halogen atom and a halo(cyclo)alkyl or haloaryl group represented by -C(Rn)(Rf2)-Ro are preferred. Preferably, R_ky3 is a halogen atom or a halo(cyclo)alkyl or haloaryl group represented by -C(Rn)(Rf2)-Ro, and R_ky2 combines with R_kyl to form a lactone ring or is an electron-withdrawing group containing no halogen atom.

R_kyi, R_ky2 and R_ky4 may combine with each other to form a monocyclic or polycyclic structure.

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

The lactone ring formed by combining R_kyi and Ricy₂ is preferably a structure of (KA-1-1) to (KA-1-17). Examples of the electron- withdrawing group are the same as those for Yi 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 in the structure.

In formula (KY-2), each of R_ky6 to R_kyio 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 R_ky6 to R_kyio may combine with each other to form a monocyclic or polycyclic structure.

R_ky5 represents an electron- withdrawing group. Examples of the electron- withdrawing group are the same as those for Yi and Y₂, and a halogen atom and a halo(cyclo)alkyl or haloaryl group represented by -C(Rn)(Rf2)-Rf3 are preferred.

Specific examples of R_ky5 to R_kyio 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). Rky5 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. Lky 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 a repeating unit obtained by addition polymerization of a carbon-carbon double bond is preferred. 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 or a derivative thereof 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 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 resin (B), 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 resin (B).

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 (A).

Ra represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

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

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 (b') 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 resin (B), 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 resin (B).

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 resin (B) 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 resin (B).

The content of the repeating unit (b¹) 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 resin (B).

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 resin (B). 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 resin (B).

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 resin (B).

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

In formula (III), R^i represents a hydrogen atom, an alkyl group, an alkyl group which may be substituted with fluorine, a cyano group or a -CH₂-0-R_ac2 group, wherein R_aC2 represents a hydrogen atom, an alkyl group or an acyl group. Rc₃₁ 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 or a cycloalkenyl group. Each of these groups may be substituted with a fluorine atom- or silicon atom-containing group or the like.

L_c3 represents a single bond or a divalent linking group.

The alkyl group of Rc₃₂ in formula (III) 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 a phenyl group or a naphthyl group, which are an aryl group having a carbon number of 6 to 20, and 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 -COO-).

The resin (B) preferably further contains a repeating unit represented by the following formula (BII-AB):

(BII-AB)

In formula (BII-AB), each of Ren' and Rci₂' 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 above-described repeating unit having at least either a fluorine atom or a silicon atom.

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 above-described repeating unit having at least either a fluorine atom or a silicon atom.

In the resin (B), similarly to the resin (A), 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 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 "polydispersity") is preferably from 1 to 3, more preferably from 1 to 2, still more preferably from 1 to 1.8, and most preferably from 1 to 1.5.

As for the resin (B), 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 (A).

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

(B-40) (B- 1) (B-42)

92

Table 1

The actinic ray-sensitive or radiation-sensitive resin composition of the present invention contains (B) a hydrophobic resin containing at least either a fluorine atom or a silicon atom, and the resin (B) 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 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 at room temperature 23±3°C, and a humidity of 45±5%.

The resin (B) 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 resin (B) 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 resin (B) 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 weight average molecular weight of the resin (B). 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 resin (B).

In the case where the resin (B) 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 weight average molecular weight of the resin (B). 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 resin (B).

The weight average molecular weight of the resin (B) is preferably from 1,000 to 100,000, more preferably from 2,000 to 50,000, still more preferably from 3,000 to 30,000. Here, the weight average molecular weight of the resin indicates a molecular weight in terms of polystyrene measured by GPC (carrier: tetrahydrofuran (THF)).

The resin (B) in the actinic ray-sensitive or radiation-sensitive resin composition may be used by appropriately adjusting its content 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 resin (B), one kind may be used alone, or two or more kinds may be used in combination.

At least either the resin (A) or the resin (B) preferably has a lactone structure. Thanks to this structure, the pattern can be prevented from swelling with a developer during development. It is more preferred that both the resin (A) and the resin (B) have a lactone structure.

[3] (C) Compound Capable of Generating Acid Upon Irradiation with Actinic Ray or Radiation

The composition of the present invention contains a compound capable of generating an acid upon irradiation with an actinic ray or radiation (hereinafter, sometimes referred to as an "acid generator").

The acid generator which can be used may be appropriately selected from a photo-initiator for cationic photopolymerization, a photo-initiator for radical photopolymerization, a photo-decoloring agent for dyes, a photo-discoloring agent, known compounds capable of generating an acid upon irradiation with an actinic ray or radiation, which are used for microresist or the like, and a mixture thereof.

Examples thereof include a diazonium salt, a phosphonium salt, a sulfonium salt, an iodonium salt, imidosulfonate, oxime sulfonate, diazodisulfone, disulfone and o- nitrobenzyl sulfonate.

Out of the acid generators, compounds represented by the following formulae (ZI), (ZII) and (ZIII) are preferred.

In formula (ZI), each of 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. Examples of the group formed by combining two members out of R₂oi to R₂₀₃ include an alkylene group (e.g., butylene, pentylene).

Z^" represents a non-nucleophilic anion.

Examples of the non-nucleophilic anion as Z^" include sulfonate anion, carboxylate anion, sulfonylimide anion, bis(alkylsulfonyl)imide anion and tris(alkylsulfonyl)methyl anion.

The non-nucleophilic anion is an anion having an extremely low ability of causing a nucleophilic reaction and this anion can suppress the decomposition with aging due to intramolecular nucleophilic reaction. Thanks to this anion, the aging stability of the actinic ray-sensitive or radiation-sensitive resin composition is enhanced.

Examples of the sulfonate anion include an aliphatic sulfonate anion, an aromatic sulfonate anion and a camphorsulfonate anion.

Examples of the carboxylate anion include an aliphatic carboxylate anion, an aromatic carboxylate anion and an aralkylcarboxylate anion.

The aliphatic moiety in the aliphatic sulfonate anion and aliphatic carboxylate may be an alkyl group or a cycloalkyl group but is preferably an alkyl group having a carbon number of 1 to 30 or a cycloalkyl group having a carbon number of 3 to 30, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an eicosyl group, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, a norbornyl group and a bornyl 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.

Each of the alkyl group, cycloalkyl group and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion may have a substituent. Examples of the substituent of the alkyl group, cycloalkyl group and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion include a nitro group, a halogen atom (e.g., fluorine, chlorine, bromine, iodine), 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). As for the aryl group and ring structure in each group, examples of the substituent further include an alkyl group (preferably having a carbon number of 1 to 15).

The aralkyl group in the aralkylcarboxylate anion is preferably an aralkyl group having a carbon number of 6 to 12, and examples thereof include a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group and a naphthylbutyl group.

Each of the alkyl group, cycloalkyl group, aryl group and aralkyl group in the aliphatic carboxylate anion, aromatic carboxylate anion and aralkylcarboxylate anion may have a substituent. Examples of the substituent include the same halogen atom, alkyl group, cycloalkyl group, alkoxy group and alkylthio group as those in the aromatic sulfonate anion.

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, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a pentyl group and a neopentyl group. Examples of the substituent of such an alkyl group 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 atom-substituted alkyl group being preferred.

Other examples of the non-nucleophilic anion include fluorinated phosphorus, fluorinated boron and fluorinated antimony.

[0337]

The non-nucleophilic anion of Z^" is preferably an aliphatic sulfonate anion substituted with a fluorine atom at least at the oc-position of 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 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.

An anion capable of generating an acid represented by the following formula (I) is also preferred as the non-nucleophilic anion of Z^".

(I)

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

Each of Ri and R₂ independently represents a hydrogen atom, a fluorine atom or an alkyl group, and when a plurality of Ri's or R₂'s are present, each Ri or R₂ may be the same as or different from every other R_\ or R₂.

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.

Cy represents a cyclic organic group.

A represents H0₃S- or Rf-NH-. Rf represents an alkyl group having at least one fluorine atom, a cycloalkyl group having at least one fluorine atom, or an aryl group having at least one fluorine atom (substitution on the cycloalkyl group or aryl group may be with an alkyl fluoride such as -CF₃ but not with a fluorine atom; specific examples of the alkyl group having at least one fluorine atom as Rf are the same as the later-described specific examples of Xf; specific examples of the cycloalkyl group having at least one fluorine atom as Rf include perfluorocyclopentyl and perfluorocyclohexyl; specific examples of the aryl group having at least one fluorine atom as Rf include perfluorophenyl group; and each of these groups may be substituted with a fluorine atom-free substituent).

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.

Formula (I) is described in detail below.

The alkyl group in the fluorine atom-substituted alkyl group of Xf 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 of Xf include a fluorine atom, CF₃, C₂F₅, C₃F₇, C₄F₉, C₅Fn, C₆Fi₃, C₇Fi₅, C₈Fi_7; CH₂CF₃, CH₂CH₂CF₃, CH₂C₂F₅, CH₂CH₂C₂Fs, CH₂C₃F₇, CH₂CH₂C₃F₇, CH₂C₄F₉ and CH₂CH₂C₄F₉. Among these, a fluorine atom and CF₃ are preferred. In particular, it is preferred that both Xf s are a fluorine atom.

The alkyl group of Ri and R₂ is preferably an alkyl group having a carbon number of 1 to 4, which may have a substituent (preferably a fluorine atom), more preferably a perfluoroalkyl group having a carbon number of 1 to 4. Specific examples of the alkyl group having a substituent of Ri and R₂ include CF₃, C₂F₅, C₃F₇, C₄F₉, C₅Fn, C₆F[₃, C₇Fi 5, C₈Fi₇, CH₂CF₃, CH₂CH2CF₃, CH₂C₂F₅, CH₂CH2C₂F₅, CH₂C₃F₇, CH₂CH₂C₃F₇, CH₂C₄F₉ and CH₂CH₂C₄F₉, with CF₃ being preferred.

Each of Ri and R₂ is preferably a fluorine atom or CF₃.

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

The divalent linking group of L is not particularly limited, and examples thereof include -COO-, -OCO-, -CO-, -0-, -S-, -SO-, -S0₂-, an alkylene group, a cycloalkylene group, an alkenylene group and a linking group formed by combining a plurality of these members. In this case, a linking group having a total carbon number of 12 or less is preferred. Among these, -COO-, -OCO-, -CO-, -O- and -S0₂- are preferred, and -COO-, -OCO- and -S0₂- are more preferred.

The cyclic organic group of Cy 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, 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, cylohexyl group and cyclooctyl group, or a polycyclic cycloalkyl group such as norbornyl group, tricyclodecanyl group, tetracyclodecanyl group, tetracyclododecanyl group and adamantyl group. Above all, a norbornyl group, a tricyclodecanyl group, a tetracyclodecanyl group, a tetracyclododecanyl group and an adamantyl group, which are an alicyclic group having a bulky structure with a carbon number of 7 or more, are preferred from the standpoint that the diffusion in film during the PEB (post-exposure baking) step can be suppressed and MEEF (mask error enhancement factor) can be improved.

The aryl group may be monocyclic or polycyclic and 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 193 nm.

The heterocyclic group may be monocyclic or polycyclic and includes those derived from a furan ring, a thiophene ring, a benzofuran ring, a benzothiophene ring, a dibenzofuran ring, a dibenzothiophene ring, a pyridine ring or a decahydroisoquinoline ring. In particular, those derived from a furan ring, a thiophene ring, a pyridine ring or a decahydroisoquinoline 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), a cycloalkyl group (may be monocyclic, polycyclic or spirocyclic, preferably having a carbon number of 3 to 20), an aryl group (preferably having a carbon number of 6 to 14), a hydroxyl group, an alkoxy group, an ester group, an amide group, a urethane group, a ureido group, a thioether group, a sulfonamide 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.

The organic group represented by R₂₀i, R₂₀₂ and R₂₀₃ include, for example, corresponding groups in the later-described compounds (ZI-1), (ZI-2), (ZI-3) and (ZI-4).

The compound may be a compound having a plurality of structures represented by formula (ZI). For example, the compound may be a compound having a structure where at least one of R₂₀₁ to R₂₀₃ in the compound represented by formula (ZI) is bonded to at least one of R₂₀i to R₂₀₃ in another compound represented by formula (ZI) through a single bond or a linking group.

Compounds (ZI-1), (ZI-2), (ZI-3) and (ZI-4) described below are more preferred as the component (ZI).

The compound (ZI-1) is an arylsulfonium compound where at least one of R₂₀i to R₂₀₃ in formula (ZI) 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 R₂₀i to R₂₀₃ may be an aryl group, with the remaining being an alkyl group or a cycloalkyl group.

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

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, a nitrogen atom, a sulfur atom or the like. Examples of the heterocyclic structure include a pyrrole residue, a furan residue, a thiophene residue, an indole residue, a benzofuran residue and a benzothiophene residue. 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 present, 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 R₂₀i to R₂₀₃ may have, as the 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 R₂₀ i to R₂₀₃ are an aryl group, the substituent is preferably substituted on the p-position of the aryl group.

The compound (ZI-2) is described below.

The compound (ZI-2) is a compound where each of R₂₀₁ to R₂₀3 in formula (ZI) independently represents an aromatic ring-free organic group. The aromatic ring as used herein includes an aromatic ring containing a heteroatom.

The aromatic ring- free organic group as R₂₀₁ to R₂₀₃ has a carbon number of generally from 1 to 30, preferably from 1 to 20. Each of R.201 to R₂₀₃ independently represents preferably an alkyl group, a cycloalkyl group, an allyl group or a vinyl group, more preferably a linear or branched 2-oxoalkyl group, a 2-oxocycloalkyl group or an alkoxycarbonylmethyl group, still more preferably a linear or branched 2-oxoalkyl group.

The alkyl group and cycloalkyl group of R₂₀i to R₂₀₃ are preferably a linear or branched alkyl group having a carbon number of 1 to 10 (such as methyl group, ethyl group, propyl group, butyl group and pentyl group), and a cycloalkyl group having a carbon number of 3 to 10 (such as cyclopentyl group, cyclohexyl group and norbornyl group). The alkyl group is more preferably a 2-oxoalkyl group or an alkoxycarbonylmethyl group. The cycloalkyl group is more preferably a 2- oxocycloalkyl group.

The 2-oxoalkyl group may be either linear or branched and is preferably a group having >C=0 at the 2-position of the above-described alkyl group.

The 2-oxocycloalkyl group is preferably a group having >C=0 at the 2- position of the above-described cycloalkyl group.

The alkoxy group in the alkoxycarbonylmethyl group is preferably an alkoxy group having a carbon number of 1 to 5 (such as methoxy group, ethoxy group, propoxy group, butoxy group and pentoxy group).

R₂oi to R₂₀₃ may be further substituted with a halogen atom, an alkoxy group (for example, having a carbon number of 1 to 5), a hydroxyl group, a cyano group or a nitro group.

The compound (ZI-3) is described below.

The compound (ZI-3) is a compound represented by the following formula (ZI-3), and this is a compound having a phenacylsulfonium salt structure.

In formula (ZI-3), each of i_c to R_5c independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, a hydroxyl group, a nitro group, an alkylthio group or an arylthio group.

Each

and R_7c independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a cyano group or an aryl group.

Each of R_x and R_y independently represents an alkyl group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocycloalkyl group, an alkoxycarbonyl alkyl group, an allyl group or a vinyl group.

Any two or more members out of Ri_c to R_5c, a pair of R_5c and R_6c, a pair of R_6c and R_7c, a pair of R_5c and R_x, or a pair of R_x and R_y may combine together to form a ring structure. This ring structure may contain an oxygen atom, a sulfur atom, a ketone group, an ester bond or an amide bond.

The ring structure above includes an aromatic or non-aromatic hydrocarbon ring, an aromatic or non-aromatic heterocyclic ring, and a polycyclic condensed ring formed by combining two or more of these rings. The ring structure includes a 3- to 10-membered ring and is preferably a 4- to 8-membered ring, more preferably a 5- or 6- membered ring.

Examples of the group formed by combining any two or more members of Rj_c to R_5c, a pair of ¾_c and R_7c, or a pair of R_x and R_y include a butylene group and a pentylene group.

The group formed by combining a pair of R_5c and R_6c or a pair of R_5c and R_x is preferably a single bond or an alkylene group, and examples of the alkylene group include a methylene group and an ethylene group.

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

The alkyl group as Rj_c to R_7c may be either linear or branched and is, for example, an alkyl group having a carbon number of 1 to 20, preferably a linear or branched alkyl group having a carbon number of 1 to 12 (such as methyl group, ethyl group, linear or branched propyl group, linear or branched butyl group, and linear or branched pentyl group). The cycloalkyl group includes, for example, a cycloalkyl group having a carbon number of 3 to 10 (such as cyclopentyl group and cyclohexyl group).

The aryl group as R_lc to R_5c is preferably an aryl group having a carbon number of 5 to 15, and examples thereof include a phenyl group and a naphthyl group.

The alkoxy group as Rj_c to R_5c may be linear, branched or cyclic and is, for example, an alkoxy group having a carbon number of 1 to 10, preferably a linear or branched alkoxy group having a carbon number of 1 to 5 (such as methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, and linear or branched pentoxy group), or a cyclic alkoxy group having a carbon number of 3 to 10 (such as cyclopentyloxy group and cyclohexyloxy group).

Specific examples of the alkoxy group in the alkoxycarbonyl group as R]_C to R_5c are the same as specific examples of the alkoxy group of R_lc to R_5c.

Specific examples of the alkyl group in the alkylcarbonyloxy group and alkylthio group as R_lc to R_5c are the same as specific examples of the alkyl group of Rj_c to R_5c.

Specific examples of the cycloalkyl group in the cycloalkylcarbonyloxy group as R_lc to R_5c are the same as specific examples of the cycloalkyl group of Rj_c to R_5c.

Specific examples of the aryl group in the aryloxy group and arylthio group as Ric to R_5c are the same as specific examples of the aryl group of R[_C to R_5c.

A compound where any one of Ri_c to R_5c is a linear or branched alkyl group, a cycloalkyl group, or a linear, branched or cyclic alkoxy group is preferred, and a compound where the sum of carbon numbers of R_lc to R_5c is from 2 to 15 is more preferred. Thanks to such a compound, the solvent solubility is more enhanced and production of particles during storage can be suppressed.

The ring structure which may be formed by combining any two or more members of Ri_c to R_5c with each other is preferably a 5- or 6-membered ring, more preferably a 6-membered ring (such as phenyl ring).

The ring structure which may be formed by combining R_5c and R6_C with each other includes a 4-membered or greater membered ring (preferably a 5- or 6-membered ring) formed together with the carbonyl carbon atom and carbon atom in formula (I) by combining R_5c and R^ with each other to constitute a single bond or an alkylene group (e.g., methylene, ethylene).

The aryl group as R_6c and R_7c is preferably an aryl group having a carbon number of 5 to 15, and examples thereof include a phenyl group and a naphthyl group.

An embodiment where R_6c and R_7c both are an alkyl group is preferred, an embodiment where each of R^ and R_7c is a linear or branched alkyl group having a carbon number of 1 to 4 is more preferred, and embodiment where both are a methyl group is still more preferred.

In the case where R_6c and R_7c are combined to form a ring, the group formed by combining R6c and R_7c is preferably an alkylene group having a carbon number of 2 to 10, and examples thereof include an ethylene group, a propylene group, a butylene group, a pentylene group and a hexylene group. Also, the ring formed by combining R_fc and R_7c may contain a heteroatom such as oxygen atom in the ring.

Examples of the alkyl group and cycloalkyl group as R_x and R_y are the same as those of the alkyl group and cycloalkyl group in R]_C to R_7c.

Examples of the 2-oxoalkyl group and 2-oxocycloalkyl group as R_x and R_y include a group having >C=0 at the 2-position of the alkyl group or cycloalkyl group as Ric to R_7c.

Examples of the alkoxy group in the alkoxycarbonylalkyl group as R_x and R_y are the same as those of the alkoxy group in R_]c to R_5c. The alkyl group is, for example, an alkyl group having a carbon number of 1 to 12, preferably a linear alkyl group having a carbon number of 1 to 5 (e.g., methyl group, ethyl group).

The allyl group as R_x and R_y is not particularly limited but is preferably an unsubstituted allyl group or an allyl group substituted with a monocyclic or polycyclic cycloalkyl group (preferably a cycloalkyl group having a carbon number of 3 to 10).

The vinyl group as R_x and R_y is not particularly limited but is preferably an unsubstituted vinyl group or a vinyl group substituted with a monocyclic or polycyclic cycloalkyl group (preferably a cycloalkyl group having a carbon number of 3 to 10).

The ring structure which may be formed by combining Rs_c and R_x with each other includes a 5-membered or greater membered ring (preferably a 5-membered ring) formed together with the sulfur atom and carbonyl carbon atom in formula (I) by combining R_5c and R_x with each other to constitute a single bond or an alkylene group (e.g., methylene group, ethylene group).

The ring structure which may be formed by combining R_x and R_y with each other includes a 5- or 6-membered ring, preferably a 5-membered ring (that is, tetra ydrothiophene ring), formed together with the sulfur atom in formula (ZI-3) by divalent R_x and R_y (e.g., methylene, ethylene, propylene).

Each of R_x and R_y is preferably an alkyl or cycloalkyl group having a carbon number of 4 or more, more preferably 6 or more, still more preferably 8 or more.

Each of Ric to R_7c, R_x and R_y may further have a substituent, and examples of such a substituent include a halogen atom (e.g., fluorine), a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an acyl group, an arylcarbonyl group, an alkoxyalkyl group, an aryloxyalkyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonyloxy group and an aryloxycarbonyloxy group.

The alkyl group includes, for example, a linear or branched alkyl group having a carbon number of 1 to 12, 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.

The cycloalkyl group includes, for example, a cycloalkyl group having a carbon number of 3 to 10, such as cyclopentyl group and cyclohexyl group.

The aryl group includes, for example, an aryl group having a carbon number of 6 to 15, such as phenyl group and naphthyl group.

The alkoxy group includes, for example, a linear, branched or cyclic alkoxy group having a carbon number of 1 to 20, such as methoxy group, ethoxy group, n- propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1- methylpropoxy group, tert-butoxy group, cyclopentyloxy group and cyclohexyloxy group.

The aryloxy group includes, for example, an aryloxy group having a carbon number of 6 to 10, such as phenyloxy group and naphthyloxy group.

The acyl group includes, for example, a linear or branched acyl group having a carbon number of 2 to 12, such as acetyl group, propionyl group, n-butanoyl, i- butanoyl, n-heptanoyl, 2-methylbutanoyl, 1 -methylbutanoyl and tert-heptanoyl.

The arylcarbonyl group includes, for example, an aryloxy group having a carbon number of 6 to 10, such as phenylcarbonyl group and naphthylcarbonyl group.

The alkoxyalkyl group includes, for example, a linear, branched or cyclic alkoxyalkyl group having a carbon number of 2 to 21, such as such as methoxymethyl group, ethoxymethyl group, 1 -methoxyethyl group, 2-methoxyethyl group, 1- ethoxyethyl group and 2-ethoxyethyl group.

The aryloxyalkyl group includes, for example, an aryloxy group having a carbon number of 7 to 12, such as phenyloxymethyl group, phenyloxyethyl group, naphthyloxymethyl group and naphthyloxyethyl group.

The alkoxycarbonyl group includes, for example, a linear, branched or cyclic alkoxycarbonyl group having a carbon number of 2 to 21 , such as methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, i-propoxycarbonyl group, n- butoxycarbonyl group, 2-methylpropoxycarbonyl group, 1 -methylpropoxycarbonyl group, tert-butoxycarbonyl group, cyclopentyloxycarbonyl group and cyclohexyloxycarbonyl group.

The aryloxycarbonyl group includes, for example, an aryloxycarbonyl group having a carbon number of 7 to 1 1, such as phenyloxycarbonyl group and naphthyloxycarbonyl group.

The alkoxycarbonyloxy group includes, for example, a linear, branched or cyclic alkoxycarbonyloxy group having a carbon number of 2 to 21, such as methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, i- propoxycarbonyloxy group, n-butoxycarbonyloxy group, tert-butoxycarbonyloxy group, cyclopentyloxycarbonyloxy group and cyclohexyloxycarbonyloxy group.

The aryloxycarbonyloxy group includes, for example, an aryloxycarbonyloxy group having a carbon number of 7 to 1 1, such as phenyloxycarbonyloxy group and naphthyloxycarbonyloxy group.

In formula (ZI-3), it is more preferred that each of Ri_c, R_2c, R4_C and R_5c independently represents a hydrogen atom and R_3c represents a group except for a hydrogen atom, that is, represents an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, a hydroxyl group, a nitro group, an alkylthio group or an arylthio group.

Specific examples of the cation in the compound represented by formula (ZI- 2) or (ZI-3) for use in the present invention are illustrated below. 109

110

The compound (ZI-4) is described below.

The compound (ZI-4) is a compound represented by the following formula (ZI-

4):

In formula (ZI-4), Ri₃ represents a hydrogen atom, a fluorine atom, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, or a group having a cycloalkyl group. These groups may have a substituent.

Ri4 represents, when a plurality of Ri₄'s are present, each independently represents, a hydroxyl group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylcarbonyl group, an alkylsulfonyl group, a cycloalkylsulfonyl group, or a group having a cycloalkyl group. These groups may have a substituent.

Each R₁₅ independently represents an alkyl group, a cycloalkyl group or a naphthyl group. Two R₁₅'s may combine with each other to form a ring. These groups may have a substituent.

1 represents an integer of 0 to 2.

r represents an integer of 0 to 8.

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

In formula (ZI-4), the alkyl group of Ri₃, R]₄ and R₁₅ is a linear or branched alkyl group preferably having a carbon number of 1 to 10, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, a 1-methylpropyl group, a tert-butyl group, an n-pentyl group, a neopentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2- ethylhexyl group, an n-nonyl group and an n-decyl group. Among these alkyl groups, a methyl group, an ethyl group, an n-butyl group and a tert-butyl group are preferred.

The cycloalkyl group of R , Ri₄ and R_{) 5} includes a monocyclic or polycyclic cycloalkyl group (preferably a cycloalkyl group having a carbon number of 3 to 20), and examples thereof include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclododecanyl, cyclopentenyl, cyclohexenyl, cyclooctadienyl, norbornyl, tricyclodecanyl, tetracyclodecanyl and adamantyl. Among these, cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl are preferred.

The alkoxy group of R₁₃ and R14 is a linear or branched alkoxy group preferably having a carbon number of 1 to 10, and examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, a 2-methylpropoxy group, a 1 -methylpropoxy group, a tert-butoxy group, an n-pentyloxy group, a neopentyloxy group, an n-hexyloxy group, an n-heptyloxy group, an n- octyloxy group, a 2-ethylhexyloxy group, an n-nonyloxy group and an n-decyloxy group. Among these alkoxy groups, a methoxy group, an ethoxy group, an n-propoxy group and an n-butoxy group are preferred.

The alkoxycarbonyl group of Ri₃ and Ri₄ is a linear or branched alkoxycarbonyl group preferably having a carbon number of 2 to 1 1 , and examples thereof include a methoxycarbonyl group, an ethoxycarbonyl group, an n- propoxycarbonyl group, an i-propoxycarbonyl group, an n-butoxycarbonyl group, a 2- methylpropoxycarbonyl group, a 1-methylpropoxycarbonyl group, a tert- butoxycarbonyl group, an n-pentyloxycarbonyl group, a neopentyloxycarbonyl group, an n-hexyloxycarbonyl group, an n-heptyloxycarbonyl group, an n-octyloxycarbonyl group, a 2-ethylhexyloxycarbonyl group, an n-nonyloxycarbonyl group and an n- decyloxycarbonyl group. Among these alkoxycarbonyl groups, a methoxycarbonyl group, an ethoxycarbonyl group and an n-butoxycarbonyl group are preferred.

The group having a cycloalkyl group of R]₃ and R₁₄ includes a monocyclic or polycyclic cycloalkyloxy group (preferably a cycloalkyl group having a carbon number of 3 to 20), and examples thereof include a monocyclic or polycyclic cycloalkyloxy group and an alkoxy group having a monocyclic or polycyclic cycloalkyl group. These groups may further have a substituent.

The monocyclic or polycyclic cycloalkyloxy group of R and Ri₄ preferably has a total carbon number of 7 or more, more preferably a total carbon number of 7 to 15, and preferably has a monocyclic cycloalkyl group. The monocyclic cycloalkyloxy group having a total carbon number of 7 or more indicates a monocyclic cycloalkyloxy group where a cycloalkyloxy group such as cyclopropyloxy group, cyclobutyloxy group, cyclopentyloxy group, cyclohexyloxy group, cycloheptyloxy group, cyclooctyloxy group and cyclododecanyloxy group arbitrarily has a substituent such as alkyl group (e.g., methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, dodecyl group, 2-ethylhexyl group, isopropyl group, sec- butyl group, tert-butyl group, isoamyl group), hydroxyl group, halogen atom (e.g., fluorine, chlorine, bromine, iodine), nitro group, cyano group, amido group, sulfonamido group, alkoxy group (e.g., methoxy group, ethoxy group, hydroxyethoxy group, propoxy group, hydroxypropoxy group, butoxy group), alkoxycarbonyl group (e.g., methoxycarbonyl group, ethoxycarbonyl group), acyl group (e.g., formyl group, acetyl group, benzoyl group), acyloxy group (e.g., acetoxy group, butyryloxy group) and carboxy group and where the total carbon number inclusive of the carbon number of an arbitrary substituent on the cycloalkyl group is 7 or more.

Examples of the polycyclic cycloalkyloxy group having a total carbon number of 7 or more include a norbornyloxy group, a tricyclodecanyloxy group, a tetracyclodecanyloxy group and an adamantyloxy group.

The alkoxy group having a monocyclic or polycyclic cycloalkyl group of R₁₃ and R₁₄ preferably has a total carbon number of 7 or more, more preferably a total carbon number of 7 to 15, and is preferably an alkoxy group having a monocyclic cycloalkyl group. The alkoxy group having a total carbon number of 7 or more and having a monocyclic cycloalkyl group indicates an alkoxy group where the above- described monocyclic cycloalkyl group which may have a substituent is substituted on an alkoxy group such as methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptoxy, octyloxy, dodecyloxy, 2-ethylhexyloxy, isopropoxy, sec-butoxy, tert-butoxy and isoamyloxy and where the total carbon number inclusive of the carbon number of the substituent is 7 or more. Examples thereof include a cyclohexylmethoxy group, a cyclopentylethoxy group and a cyclohexylethoxy group, with a cyclohexylmethoxy group being preferred.

Examples of the alkoxy group having a total carbon number of 7 or more and having a polycyclic cycloalkyl group include a norbomylmethoxy group, a norbornylethoxy group, a tricyclodecanylmethoxy group, a tricyclodecanylethoxy group, a tetracyclodecanylmethoxy group, a tetracyclodecanylethoxy group, an adamantylmethoxy group and an adamantylethoxy group, with a norbomylmethoxy group and a norbornylethoxy group being preferred.

Specific examples of the alkyl group in the alkylcarbonyl group of R¹⁴ are the same as those of the alkyl group of Ri₃ to Ri ₅.

The alkylsulfonyl or cycloalkylsulfonyl group of Ri₄ is a linear, branched or cyclic alkylsulfonyl group preferably having a carbon number of 1 to 10, and examples thereof include a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, a tert-butanesulfonyl group, an n-pentanesulfonyl group, a neopentanesulfonyl group, an n-hexanesulfonyl group, an n-heptanesulfonyl group, an n-octanesulfonyl group, a 2-ethylhexanesulfonyl group, an n-nonanesulfonyl group, an n-decanesulfonyl group, a cyclopentanesulfonyl group and a cyclohexanesulfonyl group. Among these alkylsulfonyl groups and cycloalkylsulfonyl groups, a methanesulfonyl group, an ethanesulfonyl group, an n-propanesulfonyl group, an n-butanesulfonyl group, a cyclopentanesulfonyl group and a cyclohexanesulfonyl group are preferred.

Examples of the substituent which each of the groups above may have include a halogen atom (e.g., fluorine), a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxy group, an alkoxyalkyl group, an alkoxycarbonyl group and an alkoxycarbonyloxy group.

Examples of the alkoxy group include a linear, branched or cyclic alkoxy group having a carbon number of 1 to 20, such as methoxy group, ethoxy group, n- propoxy group, i-propoxy group, n-butoxy group, 2-methylpropoxy group, 1- methylpropoxy group, tert-butoxy group, cyclopentyloxy group and cyclohexyloxy group.

Examples of the alkoxyalkyl group include a linear, branched or cyclic alkoxyalkyl group having a carbon number of 2 to 21 , such as methoxymethyl group, ethoxymethyl group, 1-methoxy ethyl group, 2-methoxyethyl group, 1-ethoxyethyl group and 2-ethoxyethyl group.

Examples of the alkoxycarbonyl group include a linear, branched or cyclic alkoxycarbonyl group having a carbon number of 2 to 21 , such as methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, i-propoxycarbonyl group, n- butoxycarbonyl group, 2-methylpropoxycarbonyl group, 1-methylpropoxycarbonyl group, tert-butoxycarbonyl group, cyclopentyloxycarbonyl group and cyclohexyloxycarbonyl group.

Examples of the alkoxycarbonyloxy group include a linear, branched or cyclic alkoxycarbonyloxy group having a carbon number of 2 to 21 , such as methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, i- propoxycarbonyloxy group, n-butoxycarbonyloxy group, tert-butoxycarbonyloxy group, cyclopentyloxycarbonyloxy group and cyclohexyloxycarbonyloxy group.

The ring structure which may be formed by combining two R₁₅'s with each other includes a 5- or 6-membered ring, preferably a 5-membered ring (that is, tetrahydrothiophene ring), formed together with the sulfur atom in formula (ZI-4) by two divalent Ris's and may be fused with an aryl group or a cycloalkyl group. The divalent Ri₅ may have a substituent, and examples of the substituent include a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkyl group, a cycloalkyl group, an alkoxy group, an alkoxyalkyl group, an alkoxycarbonyl group and an alkoxycarbonyloxy group. As for the substituent on the ring structure, a plurality of substituents may be present, and they may combine with each other to form a ring (an aromatic or non-aromatic hydrocarbon ring, an aromatic or non-aromatic heterocyclic ring, or a polycyclic condensed ring formed by combining two or more of these rings).

In formula (ZI-4), Ri₅ is preferably, for example, a methyl group, an ethyl group, a naphthyl group, or a divalent group of forming a tetrahydrothiophene ring structure together with the sulfur atom when two R₁₅'s are combined.

The substituent which R₁₃ and RH may have is preferably a hydroxyl group, an alkoxy group, an alkoxycarbonyl group or a halogen atom (particularly fluorine atom).

1 is preferably 0 or 1 , more preferably 1. r is preferably from 0 to 2.

Specific preferred examples of the cation in the compound represented by formula (ZI-4) for use in the present invention are illustrated below.

Formulae (ZII) and (ZIII) are described below.

In formulae (ZII) and (ZIII), each of R₂₀ to R₂₀₇ independently represents an aryl group, an alkyl group or a cycloalkyl group.

The aryl group of R₂₀4 to R₂o₇ is preferably a phenyl group or a naphthyl group, more preferably a phenyl group. The aryl group of R₂₀₄ to R207 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 structure of the aryl group having a heterocyclic structure include pyrrole, furan, thiophene, indole, benzofuran and benzothiophene. The alkyl or cycloalkyl group in R₂₀₄ to R₂₀₇ is preferably a linear or branched alkyl group having a carbon number of 1 to 10 (e.g., methyl, ethyl, propyl, butyl, pentyl) or a cycloalkyl group having a carbon number of 3 to 10 (e.g., cyclopentyl, cyclohexyl, norbornyl).

The aryl group, alkyl group and cycloalkyl group of R₂₀₄ to R₂₀₇ may have a substituent. Examples of the substituent which the aryl group, alkyl group and cycloalkyl group of R₂₀₄ to R₂₀₇ may have include 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 15), an alkoxy group (for example, having a carbon number of 1 to 15), a halogen atom, a hydroxyl group and a phenylthio group.

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

Other examples of the acid generator include compounds represented by the following formulae (ZIV), (ZV) and (ZVI):

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

Each of R₂₀₈, R₂o9 and R₂io 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 R₂₁₀ are the same as specific examples of the aryl group as R201, R202 and R₂₀₃ in formula (ZI-1).

Specific examples of the alkyl group and cycloalkyl group of R₂₀₈, R₂₀9 and R₂io are the same as specific examples of the alkyl group and cycloalkyl group as R₂₀₁, R₂₀₂ and R₂₀₃ in formula (ZI-2).

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

Among the acid generators, more preferred are the compounds represented by formulae (ZI) to (ZIII).

Also, the acid generator is preferably a compound that generates an acid having one sulfonic acid group or imide group, more preferably a compound that generates a monovalent perfluoroalkanesulfonic acid, a compound that generates an aromatic sulfonic acid substituted with a monovalent fluorine atom or a fluorine atom- containing group, or a compound that generates an imide acid substituted with a monovalent fluorine atom or a fluorine atom-containing group, still more preferably a sulfonium salt of fluoro-substituted alkanesulfonic acid, fluorine-substituted benzenesulfonic acid, fluorine-substituted imide acid or fluorine-substituted methide acid. In particular, the acid generator which can be used is preferably a compound that generates a fluoro-substituted alkanesulfonic acid, a fluoro-substituted benzenesulfonic acid or a fluoro-substituted imide acid, where pKa of the acid generated is -1 or less, and in this case, the sensitivity can be enhanced.

Among the acid generators, particularly preferred examples are illustrated below.

120

121

(164) (z65)



The acid generator can be synthesized by a known method, for example, can be synthesized in accordance with the method described in JP-A-2007-161707.

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

The content of the compound capable of generating an acid upon irradiation with an actinic ray or radiation in the composition is preferably from 0.1 to 40 mass%, more preferably from 1 to 30 mass%, still more preferably from 5 to 25 mass%, based on the entire solid content of the actinic ray-sensitive or radiation-sensitive resin composition.

[4] (D) Low molecular compound having a group capable of leaving by the action of an acid

The composition of the present invention may contain a low molecular compound having a group capable of leaving by the action of an acid (hereinafter, sometimes referred to as a "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 low molecular compound (D) is preferably an amine derivative having on the nitrogen atom a group capable of leaving by the action of an acid.

The low molecular 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 R' independently represents a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkoxyalkyl group. Each R' may combine with every other R' to form a ring.

R' 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.

Specific structures of this group are illustrated below.

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

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

Incidentally, the low molecular 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.

[0455]

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's may be the same or different, and two Ra's 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.

Each Rb independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkoxyalkyl group, 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.

At least two Rb's may combine to form an alicyclic hydrocarbon group, an aromatic hydrocarbon group, a heterocyclic hydrocarbon group or a derivative thereof.

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 of Ra and 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 Ra and/or 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 group 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 group 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 group 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 group or aromatic compound-derived group; a group where the group derived from a linear or branched alkane or the group derived from a cycloalkane is substituted with one or more kinds of or one or more groups of aromatic compound-derived group 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.

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, (lS,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 low molecular 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 easily synthesized from a commercially available amine by the method described, for example, in Protective Groups in Organic Synthesis, 4th edition. A most general method is a method of causing a dicarbonic acid ester or a haloformic acid ester to act on a commercially available amine to obtain the compound. In the formulae, X represents a halogen atom, and definitions and specific examples of Ra and Rb are the same as those in formula (A).

In the present invention, as for the (D) low molecular compound 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 composition of the present invention may not contain (D) a low molecular compound 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 basic compound.

The ratio between the acid generator and the low molecular compound (D) used in the composition is preferably acid generator/flow molecular compound (D) + 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 to heat treatment. The acid generator/flow molecular compound (D) + basic compound] (by mol) is more preferably from 5.0 to 200, still more preferably from 7.0 to 150.

[5] Basic Compound

The composition of the present invention preferably contains a basic compound so as to reduce the change of performance with aging from exposure to heating.

The basic compound is preferably a compound having a structure represented by the following formulae (A) to (E):

In formulae (A) to (E), each of R , R and R , 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)

201 202 * or an aryl group (having a carbon number of 6 to 20), and R and R 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 trialkylamine 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, 1,5- diazabicyclo[4,3,0]non-5-ene and l,8-diazabicyclo[5,4,0]undec-7-ene. Examples of the compound having an onium hydroxide structure include tetrabutylammonium hydroxide, triarylsulfonium hydroxide, phenacylsulfonium hydroxide and sulfonium hydroxide having a 2-oxoalkyl group, specifically, triphenyl sulfonium hydroxide, tris(tert-butylphenyl)sulfonium hydroxide, bis(tert-butylphenyl)iodonium hydroxide, phenacylthiophenium hydroxide and 2-oxopropylthiophenium hydroxide. Examples of the compound having an onium carboxylate structure include a compound where the anion moiety of the compound having an onium hydroxide structure becomes a carboxylate, such as acetate, adamantane-1 -carboxylate and 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, Ν,Ν-dimethylaniline, N,N-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.

In the phenoxy group-containing amine compound, phenoxy group-containing ammonium salt compound, sulfonic acid ester group-containing amine compound and sulfonic acid ester group-containing ammonium salt compound, at least one alkyl group is preferably bonded to the nitrogen atom. Also, an oxygen atom is preferably contained 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, structures of -CH₂CH₂0-,

-CH(CH₃)CH₂0- and -CH₂CH₂CH₂0- are preferred.

Specific examples of the phenoxy group-containing amine compound, phenoxy group-containing ammonium salt compound, sulfonic acid ester group- containing amine compound and sulfonic acid ester group-containing ammonium salt compound include, but are not limited to, Compounds (Cl-1) to (C3-3) illustrated in [0066] of U.S. Patent Application Publication 2007/0224539.

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

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

The ratio between the acid generator 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.

[6] Solvent

Examples of the solvent that can be used at the time of preparing the composition of the present invention by dissolving the above-described components include an organic solvent such as alkylene glycol monoalkyl ether carboxylate, alkylene glycol monoalkyl ether, alkyl lactate, alkyl alkoxypropionate, cyclic lactone (preferably having a carbon number of 4 to 10), monoketone compound (preferably having a carbon number of 4 to 10) which may contain a ring, alkylene carbonate, alkyl alkoxyacetate, alkyl pyruvate and alkyl acetate.

Preferred examples of the alkylene glycol monoalkyl ether carboxylate include propylene glycol monomethyl ether acetate (PGMEA: another name: 1- methoxy-2-acetoxypropane), propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether propionate, ethylene glycol monomethyl ether acetate and ethylene glycol monoethyl ether acetate.

Preferred examples of the alkylene glycol monoalkyl ether include propylene glycol monomethyl ether (PGME: another name: l-methoxy-2-propanol), propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether and ethylene glycol monoethyl ether.

Preferred examples of the alkyl lactate include methyl lactate, ethyl lactate, propyl lactate and butyl lactate. Preferred examples of the alkyl alkoxypropionate include ethyl 3- ethoxypropionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate and ethyl 3 -methoxypropionate.

Preferred examples of the cyclic lactone include β-propiolactone, β- butyrolactone, γ-butyrolactone, a-methyl-y-butyrolactone, P-methyl-y-butyrolactone, γ- valerolactone, γ-caprolactone, γ-octanoic lactone and cc-hydroxy-y-butyrolactone.

Preferred examples of the monoketone compound which may contain a ring include 2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone, 3- methyl -2-pentanone, 4-methyl-2-pentanone, 2-methyl-3-pentanone, 4,4-dimethyl-2- pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone, 3- hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-3- heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone, 2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5-hexen-2- one, 3-penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3- methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone, cyclohexanone, 3 -methyl cyclohexanone, 4-methylcyclohexanone, 4- ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6- trimethylcyclohexanone, cycloheptanone, 2-methylcycloheptanone and 3- methylcycloheptanone .

Preferred examples of the alkylene carbonate include propylene carbonate, vinylene carbonate, ethylene carbonate and butylene carbonate.

Preferred examples of the alkyl alkoxyacetate include 2-methoxyethyl acetate, 2-ethoxyethyl acetate, 2-(2-ethoxyethoxy)ethyl acetate, 3-methoxy-3-methylbutyl acetate and 1 -methoxy-2-propyl acetate.

Preferred examples of the alkyl pyruvate include methyl pyruvate, ethyl pyruvate and propyl pyruvate.

Preferred examples of the alkyl acetate include ethyl acetate and butyl acetate.

The solvent that can be preferably used includes a solvent having a boiling point of 130°C or more at ordinary temperature under atmospheric pressure, and specific examples thereof include cyclopentanone, γ-butyrolactone, cyclohexanone, ethyl lactate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, ethyl 3-ethoxypropionate, ethyl pyruvate, 2-ethoxyethyl acetate, 2-(2- ethoxyethoxy)ethyl acetate and propylene carbonate.

In the present invention, one of these solvents may be used alone, or two or more kinds thereof may be used in combination.

In the present invention, a mixed solvent prepared by mixing a solvent containing a hydroxyl group in the structure and a solvent not containing a hydroxyl group may be used as the organic solvent.

The solvent containing a hydroxyl group and the solvent not containing a hydroxyl group may be appropriately selected from the compounds exemplified above, but the solvent containing a hydroxyl group is preferably an alkylene glycol monoalkyl ether, an alkyl lactate or the like, more preferably propylene glycol monomethyl ether or ethyl lactate. The solvent not containing a hydroxyl group is preferably an alkylene glycol monoalkyl ether acetate, an alkyl alkoxypropionate, a monoketone compound which may contain a ring, a cyclic lactone, an alkyl acetate or the like, more preferably propylene glycol monomethyl ether acetate, ethyl ethoxypropionate, 2-heptanone, γ- butyrolactone, cyclohexanone or butyl acetate, and most preferably propylene glycol monomethyl ether acetate, ethyl ethoxypropionate or 2-heptanone.

The mixing ratio (by mass) of the solvent containing a hydroxyl group to the solvent not containing 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. A mixed solvent in which the solvent not containing a hydroxy group is contained in a ratio of 50 mass% or more is particularly preferred in view of coating uniformity.

The solvent preferably contains propylene glycol monomethyl ether acetate and is preferably a solvent composed of propylene glycol monomethyl ether acetate alone or a mixed solvent of two or more kinds of solvents containing propylene glycol monomethyl acetate.

[6] Surfactant

The actinic ray-sensitive or radiation-sensitive resin composition may not further contain a surfactant, but in the case of containing a surfactant, the composition preferably contains any one of fluorine-containing and/or silicon-containing surfactants (a fluorine-containing surfactant, a silicon-containing surfactant and a surfactant containing both a fluorine atom and a silicon atom), or two or more kinds thereof. By containing the above-described surfactant, the composition of the present invention can give a resist pattern enhanced in the sensitivity, resolution and adherence and reduced in the development defect when using an exposure light source of 250 nm or less, particularly 220 nm or less..

Examples of the fluorine-containing and/or silicon-containing surfactant include the surfactants described in paragraph [0276] of U.S. Patent Application Publication 2008/0248425, such as EFtop EF301 and EF303 (produced by Shin-Akita Kasei K.K.); Florad FC430, 431 and 4430 (produced by Sumitomo 3M Inc.); Megaface F171, F173, F176, F189, F113, F110, F177, F120 and R08 (produced by Dainippon Ink & Chemicals, Inc.); Surflon S-382, SCI 01 , 102, 103, 104, 105 and 106 (produced by Asahi Glass Co., Ltd.); Troysol S-366 (produced by Troy Chemical); GF-300 and GF- 150 (produced by Toagosei Chemical Industry Co., Ltd.); Surflon S-393 (produced by Seimi Chemical Co., Ltd.); EFtop EF121, EF122A, EF122B, RF122C, EF125M, EF135M, EF351, EF352, EF801, EF802 and EF601 (produced by JEMCO Inc.); PF636, PF656, PF6320 and PF6520 (produced by OMNOVA); and FTX-204G, 208G, 218G, 230G, 204D, 208D, 212D, 218D and 222D (produced by NEO^'S Co., Ltd.). In addition, polysiloxane polymer KP-341 (produced by Shin-Etsu Chemical Co., Ltd.) may also be used as the silicon-containing surfactant.

As for the surfactant, other than those known surfactants, a surfactant using a polymer having a fluoro-aliphatic group derived from a fluoro-aliphatic compound that is produced by a telomerization process (also called a telomer process) or an oligomerization process (also called an oligomer process), may be used. The fluoro- aliphatic compound can be synthesized by the method described in JP-A-2002-90991.

The polymer having a fluoro-aliphatic group is preferably a copolymer of a fluoro-aliphatic group-containing monomer with a (poly(oxyalkylene)) acrylate and/or a (poly(oxyalkylene)) methacrylate, and the polymer may have an irregular distribution or may be a block copolymer. Examples of the poly(oxyalkylene) group include a poly(oxyethylene) group, a poly(oxypropylene) group and a poly(oxybutylene) group. This group may also be a unit having alkylenes differing in the chain length within the same chain, such as block-linked poly(oxyethylene, oxypropylene and oxyethylene) and block-linked poly(oxyethylene and oxypropylene). Furthermore, the copolymer of a fluoro-aliphatic group-containing monomer and a (poly(oxyalkylene)) acrylate (or methacrylate) is not limited only to a binary copolymer but may also be a ternary or greater copolymer obtained by simultaneously copolymerizing two or more different fluoro-aliphatic group-containing monomers or two or more different (poly(oxyalkylene)) acrylates (or methacrylates).

Examples thereof include, as the commercially available surfactant, Megaface F178, F-470, F-473, F-475, F-476 and F-472 (produced by Dainippon Ink & Chemicals, Inc.) and further include a copolymer of a C₆Fi₃ group-containing acrylate (or methacrylate) with a (poly(oxyalkylene)) acrylate (or methacrylate), and a copolymer of a C₃F₇ group-containing acrylate (or methacrylate) with a (poly(oxyethylene)) acrylate (or methacrylate) and a (poly(oxypropylene)) acrylate (or methacrylate).

In the present invention, a surfactant other than the fluorine-containing and/or silicon-containing surfactant, described in paragraph [0280] of U.S. Patent Application Publication 2008/0248425, may also be used.

One of these surfactants may be used alone, or some of them may be used in combination.

In the case where the composition of the present invention contains a surfactant, the content of the surfactant used is preferably from 0.0001 to 2 mass%, more preferably from 0.0005 to 1 mass%, based on the entire solid content (entire amount excluding the solvent) of the actinic ray-sensitive or radiation-sensitive resin composition .

On the other hand, by setting the amount added of the surfactant to 10 ppm or less based on the entire amount of the resist composition (excluding the solvent), the resin (B) is more unevenly distributed to the surface, so that the resist film surface can be made more hydrophobic and the followability of water at the immersion exposure can be enhanced.

[7] Onium Carboxylate

The composition of the present invention may contain an onium carboxylate. The onium carboxylate is preferably an iodonium salt or a sulfonium salt. The anion moiety is preferably a linear or branched, monocyclic or polycyclic alkylcarboxylate anion having a carbon number of 1 to 30, more preferably the carboxylate anion above with the alkyl group being partially or entirely fluorine-substituted. The alkyl chain may contain an oxygen atom. Thanks to such a configuration, the transparency to light at 220 nm or less is ensured, the sensitivity and resolution are enhanced, and the iso/dense bias and exposure margin are improved.

Examples of the fluorine-substituted carboxylate anion include fluoroacetate, difluoroacetate, trifluoroacetate, pentafluoropropionate, heptafluorobutyrate, nonafluoropentanoate, perfluorododecanoate, perfiuorotridecanoate, perfluorocyclohexanecarboxylate and 2,2-bistrifluoromethylpropionate anions.

The composition of the present invention may not contain an onium carboxylate, but in the case of containing an onium carboxylate, the content thereof is generally from 0.1 to 20 mass%, preferably from 0.5 to 10 mass%, more preferably from 1 to 7 mass%, based on the entire solid content of the composition.

[8] Dissolution inhibiting compound having a molecular weight of 3,000 or less and being capable of decomposing by the action of an acid to increase the solubility in an alkali developer

The dissolution inhibiting compound having a molecular weight of 3,000 or less and being capable of decomposing by the action of an acid to increase the solubility in an alkali developer (hereinafter, sometimes referred to as a "dissolution inhibiting compound") is preferably an alicyclic or aliphatic compound containing an acid- decomposable group, such as acid-decomposable group-containing cholic acid derivative described in Proceeding of SPIE, 2724, 355 (1996), so as not to reduce the transmittance at 220 nm or less. Examples of the acid-decomposable group and alicyclic structure are the same as those described above with respect to the resin (A).

In the case where the composition of the present invention is exposed to KrF excimer laser or irradiated with an electron beam, the dissolution inhibiting compound preferably has a structure where a phenolic hydroxyl group of a phenol compound is substituted with an acid-decomposable group. The phenol compound is preferably a compound containing from 1 to 9 phenol structures, more preferably from 2 to 6 phenol structures.

The amount of the dissolution inhibiting compound added is preferably from 3 to 50 mass%, more preferably from 5 to 40 mass%, based on the solid content of the actinic ray-sensitive or radiation-sensitive resin composition. Specific examples of the dissolution inhibiting compound are illustrated below, but the present invention is not limited thereto.

[9] Other Additives

The composition of the present invention may further contain, for example, a dye, a plasticizer, a photosensitizer, a light absorber, and a compound for accelerating dissolution in a developer (for example, a phenol compound having a molecular weight of 1,000 or less, or a carboxyl group-containing alicyclic or aliphatic compound), if desired.

The phenol compound having a molecular weight of 1,000 or less can be easily synthesized by one skilled in the art by referring to the method described, for example, in JP-A-4-122938, JP-A-2-28531, U.S. Patent 4,916,2_.10 and European Patent 219294.

Specific examples of the carboxyl group-containing alicyclic or aliphatic compound include, but are not limited to, a carboxylic acid derivative having a steroid structure, such as cholic acid, deoxycholic acid and lithocholic acid, an adamantanecarboxylic acid derivative, an adamantanedicarboxylic acid, a cyclohexanecarboxylic acid and a cyclohexanedicarboxylic acid.

[10] Pattern Forming Method

The composition of the present invention is preferably used in a film thickness of 30 to 250 nm, more preferably from 30 to 200 nm, from the standpoint of enhancing the resolution. Such a film thickness can be obtained by setting the solid content concentration in the 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 composition is generally from 1 to 10 mass%, preferably from 1 to 8.0 mass%, more preferably from 1.0 to 6.0 mass%.

The composition of the present invention is used by dissolving the components above in a predetermined organic solvent, preferably in the above- described mixed solvent, filtering the solution, and coating it on a predetermined support as follows. The filter used for filtration 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 μιη or less.

For example, the actinic ray-sensitive or radiation-sensitive resin composition is coated on such a substrate (e.g., silicon silicon dioxide-coated substrate) as used in the production of a precision integrated circuit device, by an appropriate coating method such as spinner or coater and dried to form a film (resist film).

The film is irradiated with an actinic ray or radiation through a predetermined mask, then preferably baked (heated), and subjected to development and rinsing, whereby a good pattern can be obtained.

Examples of the actinic ray or radiation include infrared light, visible light, ultraviolet light, far ultraviolet light, extreme-ultraviolet light, X-ray and electron beam, but the radiation is preferably far ultraviolet light at a wavelength of 250 nm or less, more preferably 220 nm or less, still more preferably from 1 to 200 nm. Specific examples thereof include KrF excimer laser (248 nm), ArF excimer laser (193 nm), F₂ excimer laser (157 nm), X-ray and electron beam, and ArF excimer laser, F₂ excimer laser, EUV (13 nm) and electron beam are preferred.

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

The antireflection film 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 be also 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. 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, for example, inorganic alkali, primary amine, secondary amine, tertiary amine, alcohol amine or cyclic amine may 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.

Also, the above-described alkaline aqueous solution may be used after adding thereto alcohols and a surfactant each in an appropriate amount.

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

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

The film formed using the composition of the present invention may be exposed by immersion exposure. That is, an actinic ray or radiation may be irradiated in a state of filling a liquid having a refractive index higher than that of air between the resist film and a lens. Thanks to this exposure, the resolution can be more enhanced.

The immersion liquid used in the immersion exposure is described below.

The immersion liquid is preferably a liquid being transparent to light at the exposure wavelength and having as small a temperature coefficient of refractive index as possible so as to minimize the distortion of an optical image projected on the resist film. Particularly, in the case where the exposure light source is an ArF excimer laser (wavelength: 193 nm), water is preferably used in view of easy availability and easy handleability in addition to the above-described aspects.

Furthermore, for more shortening the wavelength, a medium having a refractive index of 1.5 or more may also be used. This medium may be either an aqueous solution or an organic solvent.

In the case of using water as the immersion liquid, for decreasing the surface tension of water and increasing the interface activity, an additive (liquid) which does not dissolve the resist film on a wafer and at the same time, gives only a negligible effect on the optical coat at the undersurface of a lens element, may be added in a small ratio.

The additive is preferably an aliphatic alcohol having a refractive index nearly equal to that of water, and specific examples thereof include methyl alcohol, ethyl alcohol and isopropyl alcohol. By adding an alcohol having a refractive index nearly equal to that of water, even when the alcohol component in water is evaporated and its content concentration is changed, the change in the refractive index of the entire liquid can be made very small. On the other hand, when a substance opaque to light at 193 nm or an impurity greatly differing in the refractive index from water is intermixed, this incurs distortion of the optical image projected on the resist film. Therefore, the water used is preferably distilled water. Pure water after further filtering the distilled water through an ion exchange filter or the like may also be used.

The electrical resistance of water used as the immersion liquid 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.

The lithography performance can be enhanced by raising the refractive index of the immersion liquid. From such a standpoint, an additive for raising the refractive index may be added to water, or heavy water (D₂0) may be used in place of water.

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

In view of transparency 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 resin (B) is suitable also as the topcoat. If impurities are dissolved out into the immersion liquid from the topcoat, the optical lens is contaminated. In this viewpoint, residual monomer components of the polymer is preferably little contained in the topcoat.

On peeling off 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 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.

Examples

The embodiment of the present invention is described in greater detail below by referring to Examples, but the scope of the present invention should not be construed as being limited to the following Examples.

Polymer A17 In a nitrogen stream, 7.28 g of a PGMEA/PGME mixed solvent (mass ratio: 8/2) was charged into a three-neck flask and heated to 85°C. To this solvent, a solution prepared by dissolving 4.49 g, 1.02 g, 0.58 g and 0.84 g of monomers above starting from the left and 0.34 g (6.5 mol% based on monomers) of polymerization initiator V601 (produced by Wako Pure Chemical Industries, Ltd.) in 13.52 g of a PGMEA/PGME mixed solvent (mass ratio: 8/2) 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 resulting reaction solution was left standing to cool and then added dropwise to a mixed solution containing 140 g of heptane and 60 g of ethyl acetate over 20 minutes, thereby precipitating a powder, and the powder precipitated was collected by filtration and dried to obtain 4.6 g of Polymer (A 17). The weight average molecular weight by GPC of the obtained Polymer (A 17) was 11,400 in terms of standard polystyrene, and the polydispersity (Mw/Mn) was 1.83.

Polymers Al to A16 and A18 to A20 shown below were synthesized in the same manner as Polymer A 17. The compositional ratio (mol%, corresponding to repeating units from the left), weight average molecular weight and polydispersity of each of Polymers Al to A20 are shown in Table 2.

Table 2

(Synthesis Example of Compound (4))

Compound (1) was synthesized by the method described in International Publication No. 07/037213, pamphlet.

Water (150.00 g) was added to 35.00 g of Compound (1), and 27.30 g of sodium hydroxide was further added. The mixture was stirred for 9 hours under heating and refluxing conditions. The resulting reaction solution was rendered acidic by adding hydrochloric acid and then extracted with ethyl acetate. The organic layers were combined and concentrated to obtain 36.90 g of Compound (2) (yield: 93%). Ή-NMR (400 MHz in (CD₃)₂CO): σ (ppm) = 1.56-1.59 (1H), 1.68-1.72 (1H), 2.13-2.15 (1H), 2.13-2.47 (2H), 3.49-3.51 (1H), 3.68 (1H), 4.45-4.46 (1H).

In the following, the reaction is performed in a nitrogen gas flow.

Ethyl acetate (300 g) was added to 50.87 g of Compound (2), and 51.76 g of 1,1,1,3,3,3-hexafluoroisopropyl alcohol and 3.18 g of 4-dimethylaminopyridine were further added, followed by stirring. To the resulting solution, 54.20 g of l-ethyl-3-(3- dimethylaminopropyl)carbodiimide hydrochloride was added, and the mixture was stirred for 5 hours. The reaction solution was added to 200 ml of 1 N HC1 to stop the reaction, and the organic layer was washed further with 1 N HC1 and then washed with water. The obtained organic layer was concentrated and water was azeotropically removed with toluene to obtain 67.60 g of Compound (3) (yield: 76%).

Subsequently, 15.00 g of Compound (3) was dissolved in 67.5 g of acetonitrile (deaerated), and the solution was bubbled with nitrogen gas and then cooled to 10°C or less. Thereto, 8.11 g of methacrylic acid chloride was added, and 7.85 g of triethylamine was added dropwise (the liquid temperature was maintained to 10°C or less). This mixture was further stirred at room temperature for 2 hours, and after the completion of reaction, the reaction solution was added to a system prepared by diluting 9.0 g of concentrated hydrochloric acid with 675 g of water and cooled to 5°C. The resulting mixture was stirred for 30 minutes, and the precipitate deposited was collected by filtration and washed with water. The obtained powder was dissolved in 45.6 g of acetonitrile, and the solution was added dropwise in 304.0 g of water at 5°C. Furthermore, the mixture was stirred for 30 minutes, and the precipitate deposited was collected by filtration and washed with water. Thereafter, 76.1 g of heptane was added to the obtained powder, and the mixture was stirred at room temperature for 1 hour and then subjected to collection by filtration and drying to obtain 13.7 g of Compound (4) (yield: 77%).

2 3 4 (Synthesis of B-29)

In a nitrogen stream, 19.8 g of a methyl ethyl ketone solvent was charged into a three-neck flask and heated to 75 °C. To this solvent, a solution prepared by dissolving 29.97 g, 2.16 g and 0.89 g of monomers above starting from the left and 1.35 g (6.5 mol% based on monomers) of polymerization initiator V601 (produced by Wako Pure Chemical Industries, Ltd.) in 79.3 g of a methyl ethyl ketone solvent was added dropwise over 4 hours. After the completion of dropwise addition, the reaction was further allowed to proceed at 75°C for 2 hours. The resulting reaction solution was left standing to cool and then added dropwise to a mixed solution containing 745 g of heptane and 186 g of ethyl acetate over 20 minutes, thereby precipitating a powder, and the powder precipitated was collected by filtration and dried to obtain 22.0 g of Polymer B-29. The weight average molecular weight by GPC of the obtained polymer was 18,000 in terms of standard polystyrene, and the polydispersity (Mw/Mn) was 1.8.

Polymers shown in Table 1 were synthesized in the same manner. <(1) ArF Immersion Exposure>

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

The components shown in Table 3 below were dissolved in a solvent to prepare a solution having a solid content concentration of 5 mass%, and the obtained solution was filtered through a polyethylene filter having a pore size of 0.1 μηι to prepare an actinic ray-sensitive or radiation-sensitive resin composition (positive resist composition). The positive photosensitive resin compositions prepared were evaluated by the following methods, and the results are shown in Table 3.

(Evaluation of Resist)

An organic antireflection film, ARC29A (produced by Nissan Chemical Industries, Ltd.), was coated on a silicon wafer and baked at 205 °C over 60 seconds to form a 98 nm-thick antireflection film on the silicon wafer, and the positive resist composition prepared above was coated thereon and baked at 130°C over 60 seconds to form a resist film having a thickness of 120 nm. The obtained resist film was subjected to pattern exposure using an ArF excimer laser immersion scanner (ΧΤ1700Ϊ, manufactured by ASML, NA: 1.20, C- Quad, outer sigma: 0.981, inner sigma: 0.895, XY deflection). Here, a 6% halftone mask with line width=65 nm and line:space=l : l was used as the reticle. Also, ultrapure water was used as the immersion liquid.

Thereafter, the resist film was heated at 130°C for 60 seconds, developed with an aqueous 2.38 mass% tetramethylammonium hydroxide solution for 30 seconds, then rinsed with pure water and spin-dried to obtain a resist pattern.

(Line Width Roughness (LWR))

A line pattern (line:space=l : l) having a line width of 65 nm was observed using a scanning electron microscope (S-9380II, manufactured by Hitachi Ltd.). The line width was measured at 50 points for the range of 2 μπι edge in the longitudinal direction of the line pattern. With respect to the measurement variation, the standard deviation was determined, and 3σ was computed. This value of 3σ was used as "LWR" (nm). A smaller value indicates higher performance.

(Development Defect)

Using a defect inspection apparatus, KLA 2360 (trade name), manufactured by KLA Tencor Ltd., measurement was performed in a random mode by setting the pixel size of the defect inspection apparatus to 0.16 μηι 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 (defects/cm²) was computed. The sample was rated A when the value was less than 0.5, rated B when from 0.5 to less than 0.8, and rated C when from 0.8 or more. A smaller value indicates higher performance.

(Pattern Collapse)

A line pattern (line/space = 1/1) having a line width of 65 nm was formed, and a pattern formed by varying the exposure dose by 10 mJxm^" to the overexposure side with respect to the exposure dose El for reproducing the mask pattern formed above was observed by a scanning electron microscope (SEM). The sample was rated A when pattern collapse did not occur, rated B when only slightly occurred, and rated C when pattern collapse occurred. (Receding Contact Angle)

The positive resist composition prepared was spin-coated on a silicon wafer and baked on a hot plate to form a resist film having a thickness of 100 nm. The receding contact angle (°) of a water droplet was measured using a dynamic contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.) by an expansion- contraction method. A droplet having an initial droplet size of 35 μΐ. was suctioned at a rate of 6 μΤ/sec for 5 seconds at room temperature 23±3°C and a humidity of 45±5%, and the value when the dynamic contact angle during suction was stabilized was taken as the receding contact angle (°).

Abbreviations in the Table are as follows. Incidentally, as for the resin (B), abbreviations corres ond to the formula numbers in specific examples illustrated above.

(Basic Compound)

DIA: 2,6-Diisopropylaniline

TMEA: Tris(methoxyethoxyethyl)amine

PEA: N-Phenyldiethanolamine TOA: Tri(n-octyl)amine

PBI: 2-Phenylbenzimidazole

DHA: N,N-Dihexylaniline

(Surfactant)

W-l : Megaface F176 (produced by Dainippon Ink & Chemicals, Inc., fluorine- containing)

W-2: Megaface R08 (produced by Dainippon Ink & Chemicals, Inc., fluorine- and silicon-containing)

W-3: Troysol S-366 (produced by Troy Chemical, fluorine-containing)

W-4: PF656 (produced by OMNOVA, fluorine-containing)

W-5 : PF6320 (produced by OMNOVA, fluorine-containing)

(Solvent)

S 1 - 1 : Propylene glycol monomethyl ether acetate

51 - 2: Cyclohexanone

52- 1 : Propylene glycol monomethyl ether

S2-2: Propylene carbonate

S2-3 : γ-Butyrolactone

Table 3

Table 3 (continued)

It is seen from Table 3 that the composition of the present invention exhibits excellent performance in terms of LWR, development defect and pattern collapse in the ArF immersion exposure and also, since the receding contact angle on the resist surface high, the composition has excellent performance in view of followability of immersion liquid at the immersion exposure.

On the other hand, the compositions of Comparative Examples 1 to 2 lack the resin (A) for use in the present invention and cannot obtain an excellent effect in all performances above.

<(2) ArF Dry Exposure>

(Preparation of Resist Composition)

The resist compositions shown in Table 4 below are the same as those described in <(1) ArF Dry Exposure> above (a solution having a solid content concentration of 5 mass%). That is, for example, Resist Composition 1 in Table 4 has the same composition as Resist Composition 1 in Table 3.

(Evaluation of Resist)

An organic antireflection film, ARC29A (produced by Nissan Chemical Industries, Ltd.), was coated on a silicon wafer and baked at 205°C for 60 seconds to form a 78-nm antireflection film, and the positive resist composition prepared above was coated 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). Thereafter, the wafer was heated at 130°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. This resist pattern was evaluated in the same manner as described above for the LWR performance, development defect performance, pattern collapse performance and receding contact angle (however, the pattern is, as described above, a 1 :1 line-and-space pattern with a line width of 75 nm).

These measurement results are shown in Table 4 below. Table 4

It is seen from Table 4 that the composition of the present invention exhibits excellent performance in terms of all of LWR, development defect and pattern collapse also in the ArF dry exposure.

On the other hand, the compositions of Comparative Examples 3 and 4 lack the resin (A) for use in the present invention and cannot obtain an excellent effect in all performances above.

Industrial Applicability

According to the present invention, an actinic ray-sensitive or radiation- sensitive resin composition improved in the line width roughness, development defect and pattern collapse and excellent in the followability of an immersion liquid at immersion exposure, and a resist film and a pattern forming method each using the composition can be provided.

The entire disclosure of Japanese Patent Application No. 2010-44797 filed on March 1, 2010, from which the benefit of foreign priority has been claimed in the present application, is incorporated herein by reference, as if fully set forth.

Claims

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

(B) a resin having at least either a fluorine atom or a silicon atom, and

2. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 1, wherein the resin (B) contains a repeating unit having at least one group selected from the group consisting of the following (x) to (z):

(x) an alkali-soluble group,

3. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 2, wherein the repeating unit having at least one group selected from the group consisting of (x) to (z) has at least either a fluorine atom or a silicon atom.

4. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 2 or 3, wherein the repeating unit having at least one group selected from the group consisting of (x) to (z), contained in the resin (B), is (by) a repeating unit having the group (y).

5. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 4, wherein the repeating unit (by) has at least one of partial structures represented by the following formulae (KA-1) and (KB-1) and the group (y) is represented by X in WO 2011/108744 , ,_Λ PCT/JP2011/055180

160 the partial structure of formula (KA-1) or (KB-1).

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

6. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 5, wherein the repeating unit (by) has a partial structure represented by formula (KA-1) and X in formula (KA-1) is a carbonic acid ester group.

The actinic ray-sensitive or radiation-sensitive resin composition according to of claims 1 to 6, wherein the structural moiety (S2) contains a lactone structure.

8. The actinic ray-sensitive or radiation-sensitive resin composition according to claim 7, wherein the structural moiety (SI) is bonded to a ring structure containing the lactone structure of the structural moiety (S2).

9. The actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 8, wherein the repeating unit (al) is a repeating unit containing a structural moiety represented by the following formula (1):

wherein Li represents a single bond, an alkylene group, an alkenylene group, a divalent aliphatic hydrocarbon ring group, a divalent aromatic ring group, or a group composed of a combination of two or more thereof and when a plurality of Li's are present, each Li may be the same as or different from every other L_\;

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

Zi2 represents a single bond, -0-, -S-, -CO-, -S0₂-, -NR-, a divalent nitrogen- containing non-aromatic heterocyclic group, or a group composed of a combination thereof and when a plurality of Z_]2's are present, each Z₁₂ may be the same as or different from every other Zj₂;

R represents a hydrogen atom or an alkyl group;

k represents an integer of 0 to 5;

10. The actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 9, wherein the content of the resin (B) is from 0.01 to 20 mass% based on the entire solid content of the actinic ray- sensitive or radiation-sensitive resin composition.

11. The actinic ray-sensitive or radiation-sensitive resin composition according to any one of claims 1 to 10, wherein the content of the resin (B) is from 0.1 to 15 mass% based on the entire solid content of the actinic ray-sensitive or radiation-sensitive resin composition.

12. A resist film formed from the actinic ray- sensitive or radiation-sensitive resin composition according to any one of claims 1 to 1 1.

13. A pattern forming method comprising steps of exposing and developing the resist film according to claim 12.

14. The pattern forming method according to claim 13, wherein the exposure is performed through an immersion liquid.