JP2007248512A - Resist composition and pattern-forming method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist composition superior in dissolution contrast by simultaneously satisfying high sensitivity, excellent line edge roughness and excellent density independence, and to provide a pattern-forming method using it. <P>SOLUTION: The resist composition contains (A) a compound generating acid by irradiation of an active optical beam or radiation and (B) a resin having a repeated unit of a specific structure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resist composition suitably used in an ultramicrolithography process such as the manufacture of VLSI and high-capacity microchips and other photo-publishing processes, and a pattern forming method using the resist composition. More particularly, the present invention relates to a resist capable of forming a highly refined pattern using KrF excimer laser light, electron beam, EUV light, and the like, and a pattern forming method using the resist. KrF excimer laser light, electron beam, The present invention relates to a resist composition that can be suitably used for microfabrication of a semiconductor element using EUV light and a pattern forming method using the resist composition.

  Conventionally, in the manufacturing process of semiconductor devices such as IC and LSI, fine processing by lithography using a resist composition has been performed. In recent years, with the high integration of integrated circuits, the formation of ultrafine patterns in the submicron region and the quarter micron region has been required. Accordingly, there is a tendency for the exposure wavelength to be shortened from g-line to i-line and further to KrF excimer laser light. Furthermore, at present, in addition to excimer laser light, lithography using electron beams, X-rays, or EUV light is also being developed.

  Lithography using an electron beam or EUV light is positioned as a next-generation or next-generation pattern forming technique, and a highly sensitive resist is desired. In particular, high sensitivity is a very important issue for shortening the wafer processing time. However, in electron beam and EUV resists, when attempting to increase the sensitivity, the dependence on density is deteriorated. Development of a resist that satisfies these characteristics simultaneously is strongly desired. Here, the density dependency means a pattern dimension difference between a portion where the resist pattern density is high and a portion where the resist pattern density is low. If this difference is large, the process margin becomes narrow during actual pattern formation. One of the important issues in resist technology development is how to reduce the size. High sensitivity and good density dependence are in a trade-off relationship, and how to satisfy this simultaneously is very important.

Further, in lithography using KrF excimer laser light, it is also important to satisfy high sensitivity and good density dependence at the same time, and it is necessary to solve these problems.
As a resist suitable for the lithography process using KrF excimer laser light, electron beam, or EUV light, a chemically amplified resist utilizing an acid-catalyzed reaction is mainly used from the viewpoint of high sensitivity. In the resist, as a main component, a phenolic polymer (hereinafter abbreviated as a phenolic acid-decomposable resin) having a property that is insoluble or hardly soluble in an antari developer and becomes soluble in an antari developer by the action of an acid, and A chemically amplified resist composition comprising an acid generator is effectively used.

With respect to these positive resists, several resist compositions using a phenolic acid-decomposable resin obtained by copolymerizing an acid-decomposable acrylate monomer having an alicyclic group as an acid-decomposable group have been known. For example, positive resist compositions disclosed in Patent Documents 1 to 5 can be exemplified.
Patent Document 6 discloses a resist containing a resin containing a repeating unit derived from cinnamic acid ester in order to improve pattern shape and etching resistance.
However, in any combination of these, at present, high sensitivity, good density dependency, and good line edge roughness in the ultrafine region are not satisfied at the same time.

US Pat. No. 5,561,194 JP 2001-166474 A JP 2001-166478 A JP 2003-107708 A JP 2001-194792 A US Pat. No. 6,312,870

  The object of the present invention is to solve the problem of performance improvement technology in microfabrication of semiconductor elements using actinic rays or radiation, in particular, KrF excimer laser light, electron beam or EUV light, and has high sensitivity and good density. An object of the present invention is to provide a resist composition that satisfies both dependency and good line edge roughness and has good dissolution contrast, and a pattern forming method using the same.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by using a resin having a repeating unit having a specific structure, and have reached the present invention.

  The present invention is as follows.

(1) A resist composition comprising (A) a compound capable of generating an acid upon irradiation with actinic rays or radiation, and (B) a resin having a repeating unit represented by the following general formula (I).

In general formula (I),
Ra represents an alkyl group.
Rb represents a hydrogen atom or a monovalent organic group.

  (2) The resist composition as described in (1), wherein in the general formula (I), Rb is a group capable of leaving by the action of an acid.

  (3) The resist composition according to (2), wherein the group capable of leaving by the action of an acid of Rb has an alicyclic structure.

(4) The resist according to any one of (1) to (3), wherein the resin of component (B) further has a repeating unit represented by the following general formula (A1) or (A2) Composition.

In general formula (A1),
A ₁ represents a group having a hydrogen atom, a group capable of leaving by the action of an acid, or a group decomposing by the action of an acid.
In general formula (A2),
A ₂ represents a group having a group capable of leaving by the action of an acid or a group decomposing by the action of an acid.
Rc represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group or an alkyloxycarbonyl group.

(5) The resist composition as described in (4), wherein in the general formula (A1), A ₁ is a hydrogen atom.

  (6) A pattern forming method comprising a step of forming a resist film, exposing and developing the resist composition according to any one of (1) to (5).

  According to the present invention, a resist composition having high sensitivity, high density dependency, excellent line edge roughness, and good dissolution contrast with respect to pattern formation by irradiation with an electron beam, KrF excimer laser light, or EUV light, and the like are used. Pattern forming method can be provided.

Hereinafter, the compounds used in the present invention will be described in detail.
In addition, in the description of the group (atomic group) in this specification, the description which does not describe substitution and non-substitution includes what has a substituent with what does not have a substituent. For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).

[1] (B) Resin Having Repeating Unit Represented by General Formula (I) The resist composition of the present invention comprises a resin having a repeating unit represented by the following general formula (I) (hereinafter referred to as “resin (B) ) ”)).

In general formula (I),
Ra represents an alkyl group.
Rb represents a hydrogen atom or a monovalent organic group.

  In the general formula (I), the alkyl group of Ra is preferably an alkyl group having 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, and a propyl group. The alkyl group of Ra may have a substituent. Examples of the substituent that the alkyl group of Ra may have include a hydroxyl group and an alkoxy group. The alkyl group for Ra is preferably a methyl group, a hydroxymethyl group or an alkoxymethyl group, more preferably a methyl group.

In the general formula (I), the monovalent organic group of Rb is a hydrocarbon group having 30 or less carbon atoms, more preferably 4 to 12 carbon atoms (preferably a linear or branched alkyl group, an alicyclic group. It is preferably a hydrocarbon group having an alicyclic structure (for example, an alicyclic group itself or a group in which an alicyclic group is substituted on an alkyl group).
The monovalent organic group of Rb may be a group that is not eliminated by the action of an acid, but is a group that is eliminated by the action of an acid and generates a carboxyl group (alkali-soluble group) in the repeating unit represented by the general formula (I) It is preferable that Also in this case, it is more preferable that the monovalent organic group of Rb has an alicyclic structure. For example, the monovalent organic group of Rb has an alicyclic structure, the atom bonded to the oxygen atom in the general formula (I) is a tertiary carbon atom, and monovalent as Rb by the action of an acid. The organic group is preferably removed to form a carboxyl group in the side chain of the repeating unit represented by the general formula (I).
The alicyclic structure may be monocyclic or polycyclic. Specific examples include monocyclo, bicyclo, tricyclo, and tetracyclo structures having 5 or more carbon atoms. The carbon number is preferably 6-30, and particularly preferably 7-25. These alicyclic rings may have a substituent.

  Although the specific example of an alicyclic structure is shown below, this invention is not limited to this.

  Examples of the alicyclic group include an adamantyl group, a noradamantyl group, a decalin residue, a tricyclodecanyl group, a tetracyclododecanyl group, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclodecanyl group. And cyclododecanyl group. More preferred are an adamantyl group, a decalin residue, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecanyl group, and a cyclododecanyl group.

  Examples of the substituent that the alicyclic group in these may have include 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 a methyl group, an ethyl group, a propyl group, an isopropyl group or a butyl group, more preferably a methyl group, an ethyl group, a propyl group or an isopropyl group.

  The monovalent organic group of Rb is preferably a group represented by the following general formula (II) that is eliminated by the action of an acid.

In general formula (II),
Rd, Re and Rf each independently represents an alkyl group or an alicyclic group.
Two of Rd, Re and Rf may combine to form an alicyclic structure.

In the general formula (II), the alkyl group of Rd, Re and Rf is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group. Group, n-butyl group, isobutyl group, sec-butyl group, pentyl group, isopentyl group, neopentyl group, t-pentyl group and the like.
The alicyclic group of Rd, Re and Rf is preferably an alicyclic group having 6 to 25 carbon atoms, such as an adamantyl group, a noradamantyl group, a decalin residue, a tricyclodecanyl group, a tetracyclododecanyl group, or a norbornyl group. , Cedrol group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecanyl group, cyclododecanyl group and the like.
Examples of the alicyclic structure formed by combining two of Rd, Re, and Rf include the alicyclic structures (1) to (50) described above.
In the group represented by the general formula (II), at least one of Rd, Re and Rf is an alicyclic group, or two of Rd, Re and Rf are bonded to form an alicyclic structure. It is preferable to do.

  Hereinafter, although the specific example of the monovalent organic group of Rb is shown, this invention is not limited to this.

  Specific examples of the repeating unit represented by the general formula (I) are shown below, but the present invention is not limited thereto.

  The resin (B) preferably further has a repeating unit represented by the following general formula (A1).

In general formula (A1),
A ₁ represents a group having a hydrogen atom, a group capable of leaving by the action of an acid, or a group decomposing by the action of an acid.

In general formula (A1), examples of the group capable of leaving by the action of an acid of A ₁ include a tertiary alkyl group such as t-butyl group and t-amyl group, t-butoxycarbonyl group, t- Examples thereof include an acetal group represented by a butoxycarbonylmethyl group, -C (L ₁ ) (L ₂ ) -OZ.
L ₁ and L ₂ may be the same or different and each represents a hydrogen atom, an alkyl group, a cycloalkyl group or an aralkyl group.
Z represents an alkyl group, a cycloalkyl group or an aralkyl group.
Z and L ₁ may be bonded to each other to form a 5- or 6-membered ring.
Examples of the group having a group capable of decomposing by the action of an acid A ₁ include, for example, an alkyl group (preferably having 1 to 10 carbon atoms) having a group (acid-decomposable group) that is decomposed by the action of an acid to generate a hydrophilic group. , A cycloalkyl group having an acid-decomposable group (preferably having 3 to 10 carbon atoms), an aryl group having an acid-decomposable group (preferably having 6 to 10 carbon atoms), and the like.
Examples of the acid-decomposable group include a group in which a hydrogen atom of an alkali-soluble group such as a carboxyl group, a phenolic hydroxyl group, a sulfonic acid group, or a thiol group is protected with a group capable of leaving by the action of an acid. .
Examples of the group capable of leaving by the action of an acid include —C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ), —C (═O) — _{O-C (R 36) (} R 37) (R 38), - C (R 01) (R 02) (OR 39), - C (R 01) (R 02) -C (= O) -O- C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ) and the like can be mentioned.
In the formula, R _{36 to} R ₃₉ each independently represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or an alkenyl group. R ₃₆ and R ₃₇ may be bonded to each other to form a ring.
R _{01 and} R ₀₂ each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or an alkenyl group.

  Hereinafter, although the specific example of the repeating unit represented by general formula (A1) is given, this invention is not limited to this.

  The resin (B) preferably further has a repeating unit represented by the following general formula (A2).

In general formula (A2),
A ₂ represents a group having a group capable of leaving by the action of an acid or a group decomposing by the action of an acid.
Rc represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group or an alkyloxycarbonyl group.

In general formula (A2), the alkyl group in the alkyl group and alkyloxycarbonyl group of Rc is preferably an alkyl group having 1 to 5 carbon atoms. The alkyl group of Rc may have a substituent. Examples of the alkyl group having a substituent include a trifluoromethyl group, an alkyloxycarbonylmethyl group, an alkylcarbonyloxymethyl group, a hydroxymethyl group, and an alkoxymethyl group. Groups and the like.
In the general formula (A2), examples of the group capable of leaving by the action of the acid of A ₂ include tertiary alkyl groups such as t-butyl and t-amyl, but preferably include an alicyclic group.
Examples of the group having a group capable of decomposing by the action of an acid A ₂ include, for example, an alkyl group (preferably having 1 to 10 carbon atoms) having a group (acid-decomposable group) that is decomposed by the action of an acid to generate a hydrophilic group , A cycloalkyl group having an acid-decomposable group (preferably having 3 to 10 carbon atoms), an aryl group having an acid-decomposable group (preferably having 6 to 10 carbon atoms), and the like.
Examples of the acid-decomposable group include the same acid-decomposable groups as described in the repeating unit represented by formula (A1).

The group capable of leaving by the action of an acid of A ₂ is preferably the following general formula (pI) to general formula (pVI).

Where
R ₁₁ represents an alkyl group, and Z represents an atomic group necessary for forming an alicyclic group together with a carbon atom.
R _{12 to} R ₁₆ each independently represents an alkyl group or an alicyclic group. At least one of R _{12 to} R ₁₄ , or any of R ₁₅ and R ₁₆ is preferably an alicyclic group.
R _{17 to} R ₂₁ each independently represents a hydrogen atom, an alkyl group, or an alicyclic group. At least one of R _{17 to} R ₂₁ is preferably an alicyclic group. Moreover, any of R ₁₉ and R ₂₁ represents an alkyl group or an alicyclic group.
R _{22 to} R ₂₅ each independently represents a hydrogen atom, an alkyl group or an alicyclic group. At least one of R _{22 to} R ₂₅ is preferably an alicyclic group. R ₂₃ and R ₂₄ may be bonded to each other to form a ring.

In the general formulas (pI) to (pVI), the alkyl group in R _{11 to} R ₂₅ may be either substituted or unsubstituted, and a linear or branched alkyl group having 1 to 4 carbon atoms. Are preferable, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group.
As further substituents for the alkyl group, an alkoxy group having 1 to 4 carbon atoms, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), acyl group, acyloxy group, cyano group, hydroxyl group, carboxy group, An alkoxycarbonyl group, a nitro group, etc. can be mentioned.

The alicyclic group in R _{12 to} R ₂₅ or the alicyclic group formed by Z and a carbon atom may be monocyclic or polycyclic. Specific examples include groups having a monocyclo, bicyclo, tricyclo, tetracyclo structure or the like having 5 or more carbon atoms. The carbon number is preferably 6-30, and particularly preferably 7-25.

  Preferred examples of the alicyclic group include an adamantyl group, a noradamantyl group, a decalin residue, a tricyclodecanyl group, a tetracyclododecanyl group, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. , Cyclodecanyl group, cyclododecanyl group and the like. More preferred are an adamantyl group, a decalin residue, a norbornyl group, a cedrol group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecanyl group, and a cyclododecanyl group.

The alicyclic group may have a substituent. Examples of the substituent for the alicyclic group include an alkyl group, a halogen atom, a hydroxyl group, an alkoxy group, a carboxyl group, and an alkoxycarbonyl group.

The group capable of leaving by the action of the acid A ₂ is preferably a group represented by the following general formula (III).

In general formula (III),
R ₄ , R ₅ , and Y each independently represent an alkyl group or an alicyclic group.

The group represented by the general formula (III) is preferably a group in which one of R _{12 to} R ₁₄ is an alicyclic group in the general formula (pII).

  Hereinafter, although the specific example of the monomer corresponding to the repeating unit represented by general formula (A2) is shown, this invention is not limited to this.

The resin (B) preferably further has a repeating unit having a group having a lactone structure. As the group having a lactone structure, any group having a lactone structure can be used, but a group having a 5- to 7-membered ring lactone structure is preferable. A structure in which another ring structure is condensed to form a structure or a spiro structure is preferable. As the group having a lactone structure, a group having a lactone structure represented by any of the following general formulas (LC1-1) to (LC1-16) is more preferable. Further, a group having a lactone structure may be directly bonded to the main chain. Preferred lactone structures include (LC1-1), (LC1-4), (LC1-5), (LC1-6), (LC1-13), (
LC1-14), and by using a specific lactone structure, line edge roughness and development defects are improved.

The lactone structure moiety may or may not have a substituent (Rb ₂ ). Preferred substituents (Rb ₂ ) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, and a carboxyl group. , Halogen atom, hydroxyl group, cyano group, acid-decomposable group and the like. n ₂ represents an integer of 0-4. When n ₂ is 2 or more, a plurality of Rb ₂ may be the same or different, and a plurality of Rb ₂ may be bonded to form a ring.

  Examples of the repeating unit having a group having a lactone structure represented by any one of the general formulas (LC1-1) to (LC1-16) include a repeating unit represented by the following general formula (AI). it can.

In general formula (AI),
Rb ₀ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms. Preferred substituents that the alkyl group represented by Rb ₀ may have include a hydroxyl group and a halogen atom.
As the halogen atom represented by Rb _0, there can be mentioned a fluorine atom, a chlorine atom, a bromine atom, an iodine atom.
Rb ₀ is 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 alicyclic hydrocarbon structure, an ether group, an ester group, a carbonyl group, a carboxyl group, or a divalent group obtained by combining these. To express.
Ab is preferably a single bond or a linking group represented by —Ab ₁ —CO ₂ —. Ab ₁ is a linear, branched alkylene group, monocyclic or polycyclic cycloalkylene group, preferably a methylene group, an ethylene group, a cyclohexyl group, an adamantyl group, or a norbornyl group.
V represents a group having a lactone structure represented by any one of the general formulas (LC1-1) to (LC1-16).

  The repeating unit 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 plurality of optical isomers may be mixed and used. When one kind of optical isomer is mainly used, the optical purity (ee) thereof is preferably 90 or more, more preferably 95 or more.

  Specific examples of the repeating unit having a group having a lactone structure are given below, but the present invention is not limited thereto.

  The resin (B) preferably further has a repeating unit having a group having an alicyclic hydrocarbon structure substituted with a polar group. This improves the substrate adhesion and developer compatibility. The alicyclic hydrocarbon structure of the alicyclic hydrocarbon structure substituted with a polar group is preferably an adamantyl group, a diamantyl group, or a norbornane group. As the polar group, a hydroxyl group and a cyano group are preferable. As the group having an alicyclic hydrocarbon structure substituted with a polar group, groups represented by the following general formulas (VIIa) to (VIId) are preferable.

In general formulas (VIIa) to (VIIc),
R ₂ c to R ₄ c each independently represents a hydrogen atom, a hydroxyl group or a cyano group. However, R ₂ c to R
_At least one of ₄ c represents a hydroxyl group or a cyano group. Preferably, one or two of R ₂ c to R ₄ c are a hydroxyl group and the remaining is a hydrogen atom. In the general formula (VIIa), more preferably, _two of R ₂ c to R ₄ c are hydroxyl groups and the rest are hydrogen atoms.

  Examples of the repeating unit having groups represented by general formulas (VIIa) to (VIId) include repeating units represented by the following general formulas (AIIa) to (AIId).

In general formulas (AIIa) to (AIId),
R ₁ c represents a hydrogen atom, a methyl group, a trifluoromethyl group or a hydroxymethyl group.

  Although the specific example of the repeating unit represented by general formula (AIIa)-(AIIb) is given to the following, this invention is not limited to these.

  The resin (B) preferably further has a repeating unit represented by the following general formula (IV).

  Hereinafter, although the specific example of the repeating unit represented by general formula (IV) is given, this invention is not limited to this.

  The resin (B) preferably further has a repeating unit represented by the following general formula (VI).

In general formula (VI),
R ₂ represents a hydrogen atom, an alkyl group, a cyano group or a halogen atom.
R ₃ represents a hydrogen atom, an alkyl group, a halogen atom, an aryl group, an alkoxy group or an acyl group.
n1 represents the integer of 0-4.
W represents a group that is not decomposed by the action of an acid.

In the general formula (VI), the alkyl group represented by R ₂ is preferably an alkyl group having 1 to 4 carbon atoms and may be substituted with a halogen atom (preferably a fluorine atom), a hydroxyl group or the like.

  Specific examples of the group that is not decomposed by the action of the acid of W (also referred to as an acid stabilizing group) include a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an acyl group, an alkylamide group, and an aryl group. An amidomethyl group, an arylamide group, etc. are mentioned. The acid stabilizing group is preferably an acyl group or an alkylamide group, and more preferably an acyl group, an alkylcarbonyloxy group, an alkyloxy group, a cycloalkyloxy group, or an aryloxy group.

  In the acid stable group of W, the alkyl group is preferably an alkyl group having 1 to 4 carbon atoms such as methyl group, ethyl group, propyl group, n-butyl group, sec-butyl group and t-butyl group. As the alkyl group, those having 3 to 10 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclohexyl group and adamantyl group are preferable, and as the alkenyl group, carbon number such as vinyl group, propenyl group, allyl group and butenyl group. Those having 2 to 4 carbon atoms are preferred, those having 2 to 4 carbon atoms such as vinyl, propenyl, allyl and butenyl groups are preferred as alkenyl groups, and phenyl, xylyl and toluyl groups are preferred as aryl groups. And those having 6 to 14 carbon atoms such as cumenyl group, naphthyl group and anthracenyl group are preferable. W may be at any position on the benzene ring, but is preferably a meta position or a para position of the styrene skeleton, particularly preferably a para position.

  Specific examples of the repeating unit represented by the general formula (VI) are shown below, but the invention is not limited thereto.

  Resin (B) is copolymerized with other polymerizable monomers suitable so that alkali-soluble groups such as phenolic hydroxyl groups and carboxyl groups can be introduced in order to maintain good developability for an alkali developer. Alternatively, in order to improve the film quality, other hydrophobic polymerizable monomers such as alkyl acrylate and alkyl methacrylate may be copolymerized.

The resin (B) preferably has a group (acid-decomposable group) that is decomposed by the action of an acid to generate a hydrophilic group such as a hydroxyl group or a carboxyl group.
The acid-decomposable group having resin (B), for example, may include those represented by _{-C (= O) -X 1 -R} 0.
In the formula, R ₀ is a tertiary alkyl group such as t-butyl group or t-amyl group, isobornyl group, 1-ethoxyethyl group, 1-butoxyethyl group, 1-isobutoxyethyl group, 1-cyclohexyloxy. 1-alkoxyethyl group such as ethyl group, 1-methoxymethyl group, alkoxymethyl group such as 1-ethoxymethyl group, 3-oxoalkyl group, tetrahydropyranyl group, tetrahydrofuranyl group, trialkylsilyl ester group, 3- An oxocyclohexyl ester group, a 2-methyl-2-adamantyl group, a mevalonic lactone residue and the like can be mentioned. X ₁ represents an oxygen atom, a sulfur atom, -NH -, - NHSO ₂ - or an -NHSO ₂ NH-.
Examples of the acid-decomposable group in the resin (B) include a —CO ₂ —Rb group (when Rb is a group capable of leaving by the action of an acid) in the general formula (I), a general formula -OA ₁ group in (A1) (when A ₁ is a group leaving by the action of an acid), -CO ₂ -A ₂ group in general formula (A2) (A ₂ is an acid group) And the like).

Resin (B) becomes acid-decomposable by having a repeating unit having an acid-decomposable group, and its solubility in an alkali developer is increased by the action of an acid.
The resist composition containing the compound (A) that generates an acid upon irradiation with actinic rays or radiation and the acid-decomposable resin (B) is a positive type. When a resist film is formed and exposed and developed, The exposed portion is dissolved and removed in an alkaline developer to form a resist pattern.
Resin (B) is a monovalent organic group in which Ra and Rb are not eliminated by the action of an acid in general formula (I), and in addition to the repeating unit represented by general formula (I), an alkali By incorporating a soluble repeating unit, it can be alkali-soluble.
Examples of the alkali-soluble repeating unit include a repeating unit represented by formula (A1) wherein A ₁ is a hydrogen atom, a repeating unit based on acrylic acid, and a repeating unit based on methacrylic acid. it can.
The resist composition containing a compound (A) that generates an acid upon irradiation with actinic rays or radiation, an alkali-soluble resin (B), and an acid crosslinking agent is a negative type, and is exposed and developed by forming a resist film. As a result, the unexposed portions are dissolved and removed, and a resist pattern is formed.
Any acid crosslinking agent can be used as long as it is a compound that crosslinks the alkali-soluble resin (B) by the action of an acid, but the following (1) to (3) are preferred.
(1) Hydroxymethyl, alkoxymethyl, and acyloxymethyl forms of phenol derivatives.
(2) A compound having an N-hydroxymethyl group, an N-alkoxymethyl group, or an N-acyloxymethyl group.
(3) A compound having an epoxy group.
The alkoxymethyl group preferably has 6 or less carbon atoms, and the acyloxymethyl group preferably has 6 or less carbon atoms.
That is, the resist composition of the present invention containing the compound (A) and the resin (B) having a repeating unit represented by the general formula (I) by irradiation with actinic rays or radiation is a positive resist composition and a negative resist composition. Any embodiment of the resist composition can be adopted.

The resin (B) preferably contains 5 to 30 mol%, more preferably 10 to 20 mol% of the repeating unit represented by the general formula (I) in all repeating units.
The resin (B) preferably contains 5 to 50 mol%, more preferably 10 to 20 mol% of the repeating unit represented by the general formula (A1) in all repeating units.
The resin (B) preferably contains 5 to 30 mol%, more preferably 10 to 20 mol% of the repeating unit represented by the general formula (A2) in all repeating units.
The resin (B) preferably contains 5 to 50 mol%, more preferably 10 to 30 mol% of the repeating unit represented by the general formula (AI) in all repeating units.
The resin (B) preferably contains 5 to 40 mol%, more preferably 10 to 25 mol% of the repeating units represented by the general formulas (AIIa) to (AIId) in all repeating units.
The resin (B) preferably contains 3 to 20 mol% of the repeating unit represented by the general formula (IV) in all repeating units, and more preferably contains 5 to 10 mol%.
The resin (B) preferably contains 5 to 30 mol%, more preferably 10 to 20 mol% of the repeating unit represented by the general formula (VI) in all repeating units.

  Resin (B), for example, acetoxystyrene and the monomer that gives the above repeating units are dissolved in an organic solvent such as THF, ethyl acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methoxybutanol, and then a nitrogen atmosphere, heating conditions Under the condition, a radical polymerization initiator such as peroxide or azo is added and reacted with stirring to polymerize, and then reprecipitated in a poor solvent for the polymerized resin such as hexane and methanol, and filtered. Then, it can be synthesized by pulverizing, dissolving it in ethyl acetate, treating with an aqueous solution of tetramethylammonium hydroxide, reprecipitating in distilled water and pulverizing. In the polymerization reaction, it is preferable to use a dropping polymerization method in which a solution obtained by dissolving the monomer in a solvent and a radical polymerization initiator are added together or separately.

The weight average molecular weight (Mw) of the resin (B) is preferably in the range of 1,000 to 15,000, more preferably in the range of 3,000 to 10,000. The dispersity (Mw / Mn) is preferably 1.0 to 2.0, more preferably 1.0 to 1.8, and particularly preferably 1.0 to 1.5.
Here, the weight average molecular weight is defined by a polystyrene conversion value of gel permeation chromatography.

Two or more types of resins (B) may be used in combination.
The total amount of the resin (B) added is generally 10 to 96% by mass, preferably 15 to 96% by mass, particularly preferably 20 to 95% by mass, based on the total solid content of the resist composition. is there.

  Although the specific example of resin (B) is given below, these are not limited.

[2] (A) Compound that generates acid upon irradiation with actinic ray or radiation Compound that generates acid upon irradiation with actinic ray or radiation contained in resist composition of the present invention (hereinafter also referred to as “acid generator”) Is preferably a compound that generates sulfonic acid upon irradiation with actinic rays or radiation.
A compound that generates sulfonic acid upon irradiation with actinic rays or radiation (hereinafter also referred to as “sulfonic acid generator”) generates sulfonic acid upon irradiation with actinic rays or radiation such as KrF excimer laser light, electron beam, EUV, etc. Examples of the compound include diazonium salts, phosphonium salts, sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, disulfones, and o-nitrobenzyl sulfonates.

Further, a group in which a sulfonic acid is generated by irradiation with these actinic rays or radiation, or a compound in which a compound is introduced into the main chain or side chain of the polymer, for example, US Pat. No. 3,849,1
37, German Patent No. 3914407, JP-A-63-26653, JP-A-55-164824, JP-A-62-69263, JP-A-63-146038, JP-A-63-163452, The compounds described in JP-A-62-153853 and JP-A-63-146029 can be used.

  Further, compounds capable of generating a sulfonic acid by light described in US Pat. No. 3,779,778, European Patent 126,712 and the like can also be used.

  In the present invention, examples of sulfonic acid generators that are preferable from the viewpoint of improving image performance such as resolution and pattern shape include sulfonium salts, iodonium salts, imide sulfonates, oxime sulfonates, diazodisulfones, and disulfones.

  Preferable examples of the sulfonic acid generator include compounds represented by the following general formulas (ZI), (ZII), and (ZIII).

In the general formula (ZI),
R ₂₀₁ , R ₂₀₂ and R ₂₀₃ each independently represents an organic group. Two of R ₂₀₁ to R ₂₀₃ are bonded to the ring structure may be formed.
X ⁻ represents an organic sulfonate anion.

The carbon number of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ is generally 1-30, preferably 1-20.

The two of the group formed by bonding of the R ₂₀₁ to R _203, an alkylene group (e.g., butylene, pentylene), and an example of an oxygen atom, a sulfur atom, an ester bond, an amide bond And may contain a carbonyl group.

Specific examples of the organic group as R ₂₀₁ , R ₂₀₂ and R ₂₀₃ include corresponding groups in the compounds (ZI-1), (ZI-2) and (ZI-3) described later.

In addition, the compound which has two or more structures represented by general formula (ZI) may be sufficient. For example, the general formula at least one of R ₂₀₁ to R ₂₀₃ of a compound represented by (ZI) is, at least one bond with structure of R ₂₀₁ to R ₂₀₃ of another compound represented by formula (ZI) It may be a compound.

  More preferred (ZI) components include compounds (ZI-1), (ZI-2) and (ZI-3) described below.

The compound (ZI-1) is at least one of the aryl groups R ₂₀₁ to R ₂₀₃ in formula (ZI), arylsulfonium compound, i.e., a compound having arylsulfonium as a cation.

In the arylsulfonium compound, all of R _{201 to} R ₂₀₃ may be an aryl group, or a part of R _{201 to} R ₂₀₃ may be an aryl group, and the rest may be an alkyl group or a cycloalkyl group.

  Examples of the arylsulfonium compound include triarylsulfonium compounds, diarylalkylsulfonium compounds, aryldialkylsulfonium compounds, diarylcycloalkylsulfonium compounds, aryldicycloalkylsulfonium compounds, and the like.

  Examples of the aryl group of the arylsulfonium compound include an aryl group composed of a hydrocarbon and a heteroaryl group having a hetero atom such as a nitrogen atom, a sulfur atom, or an oxygen atom. The aryl group composed of hydrocarbon is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. Examples of the heteroaryl group include a pyrrole group, an indole group, a carbazole group, a furan group, and a thiophene group, and an indole group is preferable. When the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same or different.

  The alkyl group that the arylsulfonium compound has as necessary is preferably a linear or branched alkyl group having 1 to 15 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, sec- Examples thereof include a butyl group and a t-butyl group.

  The cycloalkyl group that the arylsulfonium compound has as necessary is preferably a cycloalkyl group having 3 to 15 carbon atoms, and examples thereof include a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group.

The aryl group, alkyl group, and cycloalkyl group of R _{201 to} R ₂₀₃ are an alkyl group (for example, having 1 to 15 carbon atoms), a cycloalkyl group (for example, having 3 to 15 carbon atoms), an aryl group (for example, having 6 to 6 carbon atoms). 14), an alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, a phenylthio group or the like may be used as a substituent. Preferred substituents are linear or branched alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 12 carbon atoms, and alkoxy groups having 1 to 12 carbon atoms, more preferably alkyl having 1 to 4 carbon atoms. Group, an alkoxy group having 1 to 4 carbon atoms. The substituent may be substituted with any one of the three R _{201 to} R ₂₀₃ , or may be substituted with all three. When R _{201 to} R ₂₀₃ are an aryl group, the substituent is preferably substituted at the p-position of the aryl group.

Examples of the organic sulfonate anion of X ⁻ include an aliphatic sulfonate anion, an aromatic sulfonate anion, a camphor sulfonate anion, and the like.

  Examples of the aliphatic group in the aliphatic sulfonate anion include, for example, an alkyl group having 1 to 30 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, sec- Butyl, pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl And an eicosyl group and a cycloalkyl group having 3 to 30 carbon atoms, specifically, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group, a norbornyl group, a boronyl group, and the like.

  The aromatic group in the aromatic sulfonate anion is preferably an aryl group having 6 to 14 carbon atoms, such as a phenyl group, a tolyl group, and a naphthyl group.

  The alkyl group, cycloalkyl group, and aryl group in the aliphatic sulfonate anion and aromatic sulfonate anion may have a substituent.

  Examples of such substituents include nitro groups, halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms), carboxyl groups, hydroxyl groups, amino groups, cyano groups, and alkoxy groups (preferably having 1 to 5 carbon atoms). ), A cycloalkyl group (preferably 3 to 15 carbon atoms), an aryl group (preferably 6 to 14 carbon atoms), an alkoxycarbonyl group (preferably 2 to 7 carbon atoms), an acyl group (preferably 2 to 12 carbon atoms). ), An alkoxycarbonyloxy group (preferably having 2 to 7 carbon atoms), an alkylthio group (preferably having 1 to 15 carbon atoms), and the like. About the aryl group and ring structure which each group has, an alkyl group (preferably C1-C15) can further be mentioned as a substituent.

The organic sulfonate anion of X ⁻ is preferably an aliphatic sulfonate anion in which the α-position of the sulfonic acid is substituted with a fluorine atom, or an aromatic sulfonate anion substituted with a fluorine atom or a group having a fluorine atom. The organic sulfonate anion is more preferably a perfluoroaliphatic sulfonate anion having 4 to 8 carbon atoms, an aromatic sulfonate anion having a fluorine atom, particularly preferably nonafluorobutane sulfonate anion, perfluorooctane sulfonate anion, penta Fluorobenzenesulfonate anion, 3,5-bis (trifluoromethyl) benzenesulfonate anion.

Next, the compound (ZI-2) will be described.
The compound (ZI-2) is, R ₂₀₁ to R ₂₀₃ in formula (ZI) each independently is a compound when it represents an organic group having no aromatic ring.

The organic group having no aromatic ring as R ₂₀₁ to R ₂₀₃ generally has 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.

R _{201 to} R ₂₀₃ are each independently preferably an alkyl group, a cycloalkyl group, an allyl group, or a vinyl group, more preferably a linear, branched, cyclic 2-oxoalkyl group, or an alkoxycarbonylmethyl group, particularly preferably Is a linear, branched 2-oxoalkyl group.

The alkyl group as R _{201 to} R ₂₀₃ may be either linear or branched, and is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, or a propyl group. Butyl group, pentyl group and the like. More preferable examples of the alkyl group include a linear or branched 2-oxoalkyl group and an alkoxycarbonylmethyl group.

The cycloalkyl group as R ₂₀₁ to R ₂₀₃ is preferably a cycloalkyl group having 3 to 10 carbon atoms, e.g., cyclopentyl, cyclohexyl group and a norbornyl group. More preferable examples of the cycloalkyl group include a cyclic 2-oxoalkyl group.

  The 2-oxoalkyl group may be linear, branched or cyclic, and preferably includes a group having> C═O at the 2-position of the above alkyl group or cycloalkyl group.

  The alkyl group in the alkoxycarbonylmethyl group is preferably an alkyl group having 1 to 5 carbon atoms (methyl group, ethyl group, propyl group, butyl group, pentyl group).

R _{201 to} R ₂₀₃ may be further substituted with a halogen atom, an alkoxy group (eg, having 1 to 5 carbon atoms), a hydroxyl group, a cyano group, or a nitro group.

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

In general formula (ZI-3),
R _{1c to} R _5c each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxy group or a halogen atom.
R _6c and R _7c represent a hydrogen atom, an alkyl group, or a cycloalkyl group.
Rx and Ry each independently represents an alkyl group, a cycloalkyl group, an allyl group or a vinyl group.
Any two or more of R _1c to R _7c, and R _x and R _y may be bonded to each other to form a ring structure, the ring structure may contain an oxygen atom, a sulfur atom, an ester bond, an amide bond May be included. Examples of the group formed by combining any two or more of R _{1c to} R _7c and R _x and R _y include a butylene group and a pentylene group.
Zc ⁻ represents an organic sulfonate anion, and examples thereof include the same as the organic sulfonate anion of X ^{− in} formula (ZI).

The alkyl group as R _{1c to} R _7c is preferably a linear or branched alkyl group having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, a linear or branched propyl group, a linear or branched butyl group, A linear or branched pentyl group can be exemplified.

The cycloalkyl group as R _{1c to} R _7c is preferably a cycloalkyl group having 3 to 8 carbon atoms, and examples thereof include a cyclopentyl group and a cyclohexyl group.

The alkoxy group as R _{1c to} R _{5c may} be linear, branched or cyclic, for example, an alkoxy group having 1 to 10 carbon atoms, preferably a linear or branched alkoxy group having 1 to 5 carbon atoms. (For example, methoxy group, ethoxy group, linear or branched propoxy group, linear or branched butoxy group, linear or branched pentoxy group), C3-C8 cyclic alkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group) ).

Preferably, any one of R _{1c to} R _5c is a linear or branched alkyl group, a cycloalkyl group, or a linear, branched or cyclic alkoxy group, and more preferably the sum of the carbon number of R _{1c to} R _5c is 2 ~ 15. Thereby, solvent solubility improves more and generation | occurrence | production of a particle is suppressed at the time of a preservation | save.

Examples of the alkyl group and cycloalkyl group as R _x and R _y include the same as the alkyl group and cycloalkyl group as R _{1c to} R _7c , and a 2-oxoalkyl group and an alkoxycarbonylmethyl group are more preferable. preferable.

Examples of the 2-oxoalkyl group include a group having> C═O at the 2-position of the alkyl group or cycloalkyl group as R _{1c to} R _7c .

Examples of the alkoxy group in the alkoxycarbonylmethyl group include the same alkoxy groups as R _{1c to} R _5c .

R _x and R _y are preferably an alkyl group having 4 or more carbon atoms, more preferably 6 or more, and still more preferably 8 or more.

In general formulas (ZII) and (ZIII),
R ₂₀₄ to R ₂₀₇ each independently represents an aryl group, an alkyl group or a cycloalkyl group.
Examples of the aryl group of R _{204 to} R ₂₀₇ include an aryl group composed of a hydrocarbon and a heteroaryl group having a hetero atom such as a nitrogen atom, a sulfur atom, or an oxygen atom. The aryl group composed of hydrocarbon is preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. Examples of the heteroaryl group include a pyrrole group, an indole group, a carbazole group, a furan group, and a thiophene group, and an indole group is preferable.
The alkyl group as R ₂₀₄ to R ₂₀₇ is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group).
The cycloalkyl group as R ₂₀₄ to R ₂₀₇ is preferably a cycloalkyl group having 3 to 10 carbon atoms, e.g., cyclopentyl, cyclohexyl group and a norbornyl group.
The R ₂₀₄ to R ₂₀₇ are substituents which may have, for example, an alkyl group (for example, 1 to 15 carbon atoms), a cycloalkyl group (for example, 3 to 15 carbon atoms), an aryl group (e.g., 6 carbon atoms 15), alkoxy groups (for example, having 1 to 15 carbon atoms), halogen atoms, hydroxyl groups, phenylthio groups and the like.
X ⁻ represents an organic sulfonate anion, and examples thereof include the same organic sulfonate anions as X ^{− in} formula (ZI).

  Preferable examples of the sulfonic acid generator include compounds represented by the following general formulas (ZIV), (ZV), and (ZVI).

In general formulas (ZIV) to (ZVI),
Ar ₃ and Ar ₄ each independently represents an aryl group.
R ₂₀₆ , R ₂₀₇ and R _{208 each} represents an alkyl group, a cycloalkyl group or an aryl group.
A represents an alkylene group, an alkenylene group or an arylene group.

  Preferable examples of the sulfonic acid generator include compounds represented by the following general formula (ZVII).

In general formula (ZVII),
R _210a and R _211a each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a cyano group, a nitro group or an alkoxycarbonyl group, preferably a halogen-substituted alkyl group or a cycloalkyl group, a nitro group or a cyano group. is there.
R _212a represents a hydrogen atom, an alkyl group, a cycloalkyl group, a cyano group or an alkoxycarbonyl group.
X _1a represents a monovalent group formed by removing a hydrogen atom of —SO ₃ H of an organic sulfonic acid.

  Preferred examples of the sulfonic acid generator include compounds represented by the following general formula (ZVIII).

In general formula (ZVIII):
Ra represents an alkyl group, a cycloalkyl group, or an aryl group. When there are a plurality of Ras, the plurality of Ras may be the same or different.
n represents an integer of 1 to 6.

  Hereinafter, although the specific example of a sulfonic acid generator is given, this invention is not limited to this.

The content of the sulfonic acid generator is 5 to 20% by mass, preferably 6 to 18% by mass, particularly preferably 7 to 16% by mass, based on the solid content of the resist composition. It is 5% by mass or more from the viewpoint of sensitivity and line edge roughness, and 20% by mass or less from the viewpoint of resolution, pattern shape, and film quality. Moreover, one type of sulfonic acid generator may be used, or two or more types may be mixed and used. For example, as the sulfonic acid generator, a compound that generates aryl sulfonic acid upon irradiation with active light or radiation and a compound that generates alkyl sulfonic acid upon irradiation with active light or radiation may be used in combination.
The sulfonic acid generator can be synthesized by a known method such as a synthesis method described in JP-A-2002-27806.

The resist composition of the present invention may use, together with a sulfonic acid generator, a compound that generates a carboxylic acid upon irradiation with actinic rays or radiation (hereinafter also referred to as “carboxylic acid generator”).
As the carboxylic acid generator, a compound represented by the following general formula (C) is preferable.

In general formula (C),
R _{21 to} R ₂₃ each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, or an aryl group.
R ₂₄ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group or an aryl group.
Z represents a sulfur atom or an iodine atom. When Z is a sulfur atom, p is 1, and when Z is an iodine atom, p is 0.

In the general formula (C), R _{21 to} R ₂₃ each independently represents an alkyl group, a cycloalkyl group, an alkenyl group, or an aryl group, and these groups may have a substituent.
Examples of the substituent that the alkyl group, cycloalkyl group or alkenyl group may have include a halogen atom (a chlorine atom, a bromine atom, a fluorine atom, etc.), an aryl group (a phenyl group, a naphthyl group, etc.), a hydroxy group, An alkoxy group (methoxy group, ethoxy group, butoxy group, etc.) etc. can be mentioned.
Examples of the substituent that the aryl group may have include a halogen atom (chlorine atom, bromine atom, fluorine atom, etc.), nitro group, cyano group, alkyl group (methyl group, ethyl group, t-butyl group, t -Amyl group, octyl group, etc.), hydroxy group, alkoxy group (methoxy group, ethoxy group, butoxy group, etc.) and the like.

R _{21 to} R ₂₃ are preferably each independently an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or an aryl group having 6 to 24 carbon atoms. And more preferably an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 18 carbon atoms, and particularly preferably an aryl group having 6 to 15 carbon atoms. Each of these groups may have a substituent.

R ₂₄ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group or an aryl group.
Examples of the substituent that the alkyl group, cycloalkyl group, and alkenyl group may have are the same as those described as examples of the substituent when R ₂₁ is an alkyl group. Examples of the substituent for the aryl group, the R ₂₁ may be the same as those mentioned as examples of the substituent when it is an aryl group.

R ₂₄ is preferably a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, an aryl group having 6 to 24 carbon atoms, and more Preferably, they are a C1-C18 alkyl group, a C3-C18 cycloalkyl group, and a C6-C18 aryl group, Most preferably, a C1-C12 alkyl group, C3-C3 A cycloalkyl group having 12 carbon atoms and an aryl group having 6 to 15 carbon atoms. Each of these groups may have a substituent.

Z represents a sulfur atom or an iodine atom. p is 1 when Z is a sulfur atom, and 0 when Z is an iodine atom.
In addition, the cation structure which has two or more of the cation part of general formula (C) couple | bonded by the single bond or the coupling group (for example, -S-, -O-, etc.), and has two or more cation parts of general formula (C). May be formed.

  Although the preferable specific example of the compound which generate | occur | produces carboxylic acid by irradiation of actinic light or a radiation below is given, of course, it is not limited to these.

The content of the carboxylic acid generator in the resist composition of the present invention is preferably 0.01 to 10% by mass, more preferably 0.03 to 5% by mass, particularly based on the total solid content of the composition. Preferably it is 0.05-3 mass%. In addition, these compounds that generate a carboxylic acid upon irradiation with actinic rays or radiation may be used alone or in combination of two or more.
The carboxylic acid generator / sulfonic acid generator (mass ratio) is usually 99.9 / 0.1 to 50/50, preferably 99/1 to 60/40, and particularly preferably 98/2 to 70/30. .
The carboxylic acid generator can be synthesized by a known method such as the synthesis method described in JP-A-2002-27806.

[3] Basic Compound In the present invention, it is preferable to use a basic compound from the viewpoints of improving performance such as resolution and improving storage stability. As the basic compound, a compound containing a nitrogen atom (nitrogen-containing organic basic compound) is more preferable.
A preferable basic compound in the present invention is a compound having a stronger basicity than phenol.
As a preferable chemical environment, structures of the following formulas (A) to (E) can be exemplified. Formulas (B) to (E) may be part of a ring structure.

In general formula (A),
R ²⁰⁰ , R ²⁰¹ and R ²⁰² may be the same or different and each represents a hydrogen atom, an alkyl or cycloalkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, R ²⁰¹ and R ²⁰² may combine with each other to form a ring.
The alkyl group, cycloalkyl group and aryl group as R ²⁰⁰ , R ²⁰¹ and R ²⁰² may have a substituent. As the alkyl group and cycloalkyl group having a substituent, an aminoalkyl group having 1 to 20 carbon atoms and an aminocycloalkyl group, and a hydroxyalkyl group having 1 to 20 carbon atoms are preferable.
In general formula (E),
R ²⁰³ , R ²⁰⁴ , R ²⁰⁵ and R ²⁰⁶ may be the same or different and each represents an alkyl group having 1 to 6 carbon atoms and a cycloalkyl group.

  Further preferred compounds are nitrogen-containing organic basic compounds having two or more nitrogen atoms of different chemical environments in one molecule, and particularly preferably both a substituted or unsubstituted amino group and a ring structure containing a nitrogen atom. Or a compound having an alkylamino group.

Preferred examples include guanidine, aminopyridine, aminoalkylpyridine, aminopyrrolidine, indazole, imidazole, pyrazole, pyrazine, pyrimidine, purine, imidazoline, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine and the like. Preferred substituents that these may have include amino groups, alkylamino groups, aminoaryl groups, arylamino groups, alkyl groups (substituent alkyl groups, particularly aminoalkyl groups), alkoxy groups, acyl groups, and acyloxy groups. , Aryl group, aryloxy group, nitro group, hydroxyl group, cyano group and the like.

Particularly preferred compounds include guanidine, 1,1-dimethylguanidine, 1,1,3,3-tetramethylguanidine, imidazole, 2-methylimidazole, 4-methylimidazole, N-methylimidazole, 2-phenylimidazole, 4 , 5-diphenylimidazole, 2,4,5-triphenylimidazole, 2-aminopyridine, 3-aminopyridine, 4-aminopyridine, 2-dimethylaminopyridine, 4-dimethylaminopyridine, 2-diethylaminopyridine, 2- (Aminomethyl) pyridine, 2-amino-3-methylpyridine, 2-amino-4-methylpyridine, 2-amino-5-methylpyridine, 2-amino-6-methylpyridine, 3-aminoethylpyridine, 4- Aminoethylpyridine, 3-aminopyrrolidine, Perazine, N- (2-aminoethyl) piperazine, N- (2-aminoethyl) piperidine, 4-amino-2,2,6,6-tetramethylpiperidine, 4-piperidinopiperidine, 2-iminopiperidine, 1- (2-aminoethyl) pyrrolidine, pyrazole, 3-amino-5-methylpyrazole, 5-amino-3-methyl-1-p-tolylpyrazole, pyrazine, 2- (aminomethyl) -5-methylpyrazine, Examples include, but are not limited to, pyrimidine, 2,4-diaminopyrimidine, 4,6-dihydroxypyrimidine, 2-pyrazoline, 3-pyrazoline, N-aminomorpholine, N- (2-aminoethyl) morpholine. It is not a thing.
These nitrogen-containing organic basic compounds are used alone or in combination of two or more.

  Further, a tetraalkylammonium salt type nitrogen-containing basic compound can also be used. Of these, tetraalkylammonium hydroxide having 1 to 8 carbon atoms (tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetra- (n-butyl) ammonium hydroxide, etc.) is particularly preferable. These nitrogen-containing basic compounds are used alone or in combination of two or more.

  The use ratio of the acid generator and the basic compound in the composition is preferably (total amount of acid generator) / (basic compound) (molar ratio) = 2.5 to 300. By setting the molar ratio to 2.5 or more, high sensitivity is obtained, and by setting the molar ratio to 300 or less, it is possible to suppress the resist pattern from becoming thicker over time until post-exposure heat treatment and improve resolution. . (Total amount of acid generator) / (basic compound) (molar ratio) is preferably 5.0 to 200, more preferably 7.0 to 150.

[4] Surfactants In the present invention, surfactants can be used, which are preferable from the viewpoints of film forming properties, pattern adhesion, development defect reduction, and the like.

Specific examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene Polyoxyethylene alkyl allyl ethers such as nonylphenol ether, polyoxyethylene / polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Sorbitan fatty acid esters such as rate, polyoxyethylene sorbitan monolaurate, polyoxyethylene Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as bitane monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tristearate, Ftop EF301, EF303, EF352 (manufactured by Shin-Akita Kasei Co., Ltd.), Megafac F171, F173 (manufactured by Dainippon Ink and Chemicals), Florad FC430, FC431 (manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S-382, SC101, SC102, SC103, SC104, SC105, SC106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.) and other fluorine-based surfactants or silicon-based surfactants, organosilanes Hexane polymer KP341 (manufactured by Shin-Etsu Chemical Co.) and acrylic or methacrylic acid-based (co) polymer Polyflow No. 75, no. 95 (manufactured by Kyoeisha Yushi Chemical Co., Ltd.).

The compounding amount of these surfactants is usually 2 parts by mass or less, preferably 1 part by mass or less per 100 parts by mass of the solid content in the resist composition of the present invention.
These surfactants may be added alone or in some combination.

As the surfactant, any one of fluorine-based and / or silicon-based surfactants (fluorine-based surfactant and silicon-based surfactant, surfactant containing both fluorine atom and silicon atom), or two kinds of surfactants It is preferable to contain the above.
As these surfactants, for example, JP-A-62-36663, JP-A-61-226746, JP-A-61-226745, JP-A-62-170950, JP-A-63-34540 No. 7, JP-A-7-230165, JP-A-8-62834, JP-A-9-54432, JP-A-9-5988, JP-A 2002-277862, US Pat. No. 5,405,720. , No. 5,360,692, No. 5,529,881, No. 5,296,330, No. 5,543,098, No. 5,576,143, No. 5,294,511, No. 5,824,451. The following commercially available surfactants can also be used as they are.
Examples of commercially available surfactants that can be used include F-top EF301, EF303 (manufactured by Shin-Akita Kasei Co., Ltd.), Florard FC430, 431 (manufactured by Sumitomo 3M Co., Ltd.), MegaFuck F171, F173, F176, F189, R08 (Dainippon Ink Chemical Co., Ltd.), Surflon S-382, SC101, 102, 103, 104, 105, 106 (Asahi Glass Co., Ltd.), Troisol S-366 (Troy Chemical Co., Ltd.), etc. Fluorine type surfactant or silicon type surfactant can be mentioned. Polysiloxane polymer KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.) can also be used as a silicon-based surfactant.

In addition to the known surfactants described above, the surfactant is derived from a fluoroaliphatic compound produced by a telomerization method (also called telomer method) or an oligomerization method (also called oligomer method). A surfactant using a polymer having a fluoroaliphatic group can be used. The fluoroaliphatic compound can be synthesized by the method described in JP-A-2002-90991.
As the polymer having a fluoroaliphatic group, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate and / or (poly (oxyalkylene)) methacrylate is preferable and distributed irregularly. Or may be block copolymerized. Examples of the poly (oxyalkylene) group include a poly (oxyethylene) group, a poly (oxypropylene) group, a poly (oxybutylene) group, and the like, and a poly (oxyethylene, oxypropylene, and oxyethylene group). A unit having different chain lengths in the same chain length, such as a block linked body) or a poly (block linked body of oxyethylene and oxypropylene) group, may be used. Furthermore, a copolymer of a monomer having a fluoroaliphatic group and (poly (oxyalkylene)) acrylate (or methacrylate) is not only a binary copolymer but also a monomer having two or more different fluoroaliphatic groups, Further, it may be a ternary or higher copolymer obtained by simultaneously copolymerizing two or more different (poly (oxyalkylene)) acrylates (or methacrylates).
Examples of commercially available surfactants include Megafac F178, F-470, F-473, F-475, F-476, and F-472 (Dainippon Ink Chemical Co., Ltd.). Further, a copolymer of an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxyalkylene)) acrylate (or methacrylate), an acrylate (or methacrylate) having a C ₆ F ₁₃ group and (poly (oxy) (Ethylene)) acrylate (or methacrylate) and (poly (oxypropylene)) acrylate (or methacrylate) copolymer, acrylate (or methacrylate) and (poly (oxyalkylene)) acrylate having C ₈ F ₁₇ groups (or Copolymer of acrylate (or methacrylate), (poly (oxyethylene)) acrylate (or methacrylate), and (poly (oxypropylene)) acrylate (or methacrylate) having a C ₈ F ₁₇ group Coalesce, etc. Can.

  The amount of the surfactant used is preferably 0.0001 to 2% by mass, more preferably 0.001 to 1% by mass, based on the total amount of the resist composition (excluding the solvent).

[5] Other components The resist composition of the present invention may further contain a dye, a photobase generator and the like, if necessary.

1. Dye A dye can be used in the present invention.
Suitable dyes include oily dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (oriental chemical industry) Co., Ltd.), crystal violet (CI42555), methyl violet (CI42535), rhodamine B (CI45170B), malachite green (CI42000), methylene blue (CI522015) and the like.

2. Photobase generator As photobase generators that can be added to the composition of the present invention, JP-A-4-151156, JP-A-4-162040, JP-A-5-197148, JP-A-5-5995, JP-A-6-194835, Examples thereof include compounds described in JP-A-8-146608, JP-A-10-83079 and European Patent No. 622682, specifically, 2-nitrobenzylcarbamate, 2,5-dinitrobenzylcyclohexylcarbamate, N-cyclohexyl-4- Methylphenylsulfonamide, 1,1-dimethyl-2-phenylethyl-N-isopropylcarbamate and the like can be suitably used. These photobase generators are added for the purpose of improving the resist shape and the like.

3. Solvents The resist composition of the present invention is dissolved in a solvent that dissolves each of the above components and coated on a support. The solid content concentration of all resist components is usually preferably 2 to 30% by mass, more preferably 3 to 25% by mass.
Solvents used here include ethylene dichloride, cyclohexanone, cyclopentanone, 2-heptanone, γ-butyrolactone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, ethylene glycol monoethyl ether acetate , Propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate, methyl methoxypropionate, ethyl ethoxypropionate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, N, N-dimethyl Formamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran and the like are preferable. Or mixed to use.

  The resist composition of the present invention is applied onto a substrate to form a thin film. The thickness of this coating film is preferably 0.05 to 4.0 μm.

  In the present invention, a commercially available inorganic or organic antireflection film can be used if necessary. Furthermore, an antireflection film can be applied to the resist lower layer and used.

  As the antireflection film used as the lower layer of the resist, either an inorganic film type such as titanium, titanium dioxide, titanium nitride, chromium oxide, carbon, amorphous silicon, or an organic film type made of a light absorber and a polymer material may be used. it can. The former requires equipment such as a vacuum deposition apparatus, a CVD apparatus, and a sputtering apparatus for film formation. Examples of the organic antireflection film include a condensate of a diphenylamine derivative and a formaldehyde-modified melamine resin described in JP-B-7-69611, an alkali-soluble resin, a light absorber, and maleic anhydride copolymer described in US Pat. No. 5,294,680. A reaction product of a coalescence and a diamine type light absorbent, a resin binder described in JP-A-6-186863 and a methylolmelamine thermal crosslinking agent, a carboxylic acid group, an epoxy group and a light-absorbing group described in JP-A-6-118656. An acrylic resin-type antireflection film in the same molecule, a composition comprising methylol melamine and a benzophenone-based light absorber described in JP-A-8-87115, and a low-molecular light absorber added to a polyvinyl alcohol resin described in JP-A-8-179509. And the like.

  In addition, as the organic antireflection film, commercially available organic antireflection films such as DUV30 series, DUV-40 series manufactured by Brewer Science, and AR-2, AR-3, AR-5 manufactured by Shipley may be used. it can.

  In the manufacture of precision integrated circuit elements, etc., the pattern formation process on the resist film is carried out on the substrate (eg, silicon / silicon dioxide coated substrate, glass substrate, ITO substrate, quartz / chromium oxide coated substrate). Apply the composition, form a resist film, and then irradiate with actinic rays or radiation such as KrF excimer laser light, electron beam, EUV light, etc. to form a good resist pattern by heating, developing, rinsing and drying can do.

Examples of the alkaline developer used in development include inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, and aqueous ammonia, and primary amines such as ethylamine and n-propylamine. Secondary amines such as diethylamine and di-n-butylamine, tertiary amines such as triethylamine and methyldiethylamine, alcoholamines such as dimethylethanolamine and triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, An aqueous solution (usually 0.1 to 20% by mass) of an alkali such as a quaternary ammonium salt such as choline or a cyclic amine such as pyrrole or piperidine can be used. Furthermore, an appropriate amount of an alcohol such as isopropyl alcohol or a nonionic surfactant may be added to the alkaline aqueous solution.
Among these developers, quaternary ammonium salts are preferable, and tetramethylammonium hydroxide and choline are more preferable.
The pH of the alkali developer is usually 10-15.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, the content of this invention is not limited by this.

Synthesis Example 1 (Synthesis of Resin (P-6))
4-Acetoxystyrene, 4-t-butoxystyrene, 2-methyl-2-adamantyl crotonate are charged at a ratio (molar ratio) of 60/20/20, dissolved in tetrahydrofuran, and 100 mL of a solution having a solid content concentration of 20% by mass. Was prepared. To this solution, 2 mol% of a polymerization initiator V-65 manufactured by Wako Pure Chemical Industries, Ltd. was added and added dropwise to 10 mL of tetrahydrofuran heated to 60 ° C. over 4 hours in a nitrogen atmosphere. After completion of the dropwise addition, the reaction solution was heated for 4 hours, 1 mol% of V-65 was added again, and the mixture was stirred for 4 hours. After completion of the reaction, the reaction solution was cooled to room temperature, crystallized in 3 L of hexane, and the precipitated white powder was collected by filtration.
This polymer was dissolved in 100 ml of acetone, 5 ml of hydrochloric acid was added and stirred for 1 hour, and distilled water was added to precipitate the polymer. The precipitate was washed with distilled water and then dried under reduced pressure. After dissolving the polymer in 100 ml of ethyl acetate, hexane was added and the precipitated polymer was powdered by drying under reduced pressure. The weight average molecular weight in terms of standard polystyrene determined by GPC measurement for this powder was 5,500. The composition ratio of the polymer determined from C ¹³ NMR was 60/20/20 (molar ratio).

  Resins exemplified in the structure shown in Table 1 below were synthesized in the same manner as in Synthesis Example 1. In Table 1, the repeating unit (mol%) corresponds to each repeating unit in order from the left.

  The acid generator used in the examples was synthesized by a known synthesis method such as the synthesis method described in JP-A-2002-27806.

Example 1
(1) Preparation and coating of positive resist Resin (P-2) 0.93g
0.07 g of acid generator (B-2)
Was dissolved in 8.8 g of propylene glycol monomethyl ether acetate, 0.001 g of D-1 (see below) as a basic compound, and MegaFac F176 (manufactured by Dainippon Ink & Chemicals, Inc.) as a surfactant. 0.001 g) (abbreviated as “W-1”) was added and dissolved, and the resulting solution was microfiltered with a 0.1 μm aperture membrane filter to obtain a resist solution.
This resist solution was applied onto a 6-inch silicon wafer using a spin coater Mark8 manufactured by Tokyo Electron, and baked at 110 ° C. for 90 seconds to obtain a uniform film having a thickness of 0.25 μm.

(2) Formation of positive resist pattern This resist film was irradiated with an electron beam using an electron beam drawing apparatus (HL750, acceleration voltage 50 KeV manufactured by Hitachi, Ltd.). After irradiation, it was baked at 110 ° C. for 90 seconds, immersed in an aqueous 2.38 mass% tetramethylammonium hydroxide (TMAH) solution for 60 seconds, rinsed with water for 30 seconds and dried. The obtained pattern was evaluated by the following method.

(2-1) Sensitivity The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope (S-4300, manufactured by Hitachi, Ltd.). The minimum irradiation energy when resolving a 0.15 μm line (line: space = 1: 1) was defined as sensitivity.
(2-2) LWR (Line Edge Roughness)
About the resist pattern obtained by carrying out similarly to the above, the line width was observed with the scanning electron microscope (S-9220 by Hitachi, Ltd.), and the fluctuation | variation (LWR) of the line width in the line width of 130 nm was observed. Using a length-measuring scanning electron microscope (SEM), the line width was detected at a plurality of positions in the measurement monitor, and the dispersion (3σ) of variations in the detected positions was used as an LWR index.
(2-3) Dense / Dense Dependence The line width of the dense pattern (line: space = 1: 1) and the line width of the isolated pattern in the 0.15 μm line pattern at the irradiation dose showing the above sensitivity are measured, and the difference between them is measured. Sparse and dense dependence.

As a result of Example 1, the sensitivity was 10.0 μC / cm ² , the LWR was 6.5, and the density dependency was 11 nm.

Examples 2 to 7 and Comparative Example 1
Resist preparation, coating, and electron beam exposure evaluation were performed in the same manner as in Example 1 using the compounds shown in Table 2 below. The evaluation results are shown in Table 2.

  Abbreviations in the table are as follows.

[Basic compounds]
D-1: tri-n-hexylamine D-2: 2,4,6-triphenylimidazole D-3: tetra- (n-butyl) ammonium hydroxide

[Surfactant]
W-1: Fluorosurfactant (Megafac F-176, manufactured by Dainippon Ink & Chemicals, Inc.)
W-2: Fluorine / silicone surfactant (Megafac R08, manufactured by Dainippon Ink & Chemicals, Inc.)
W-3: Silicone surfactant (siloxane polymer KP341, manufactured by Shin-Etsu Chemical Co., Ltd.)

  〔resin〕

  From Table 2, it can be seen that the positive resist composition of the present invention has higher sensitivity and excellent line edge roughness and density dependency in comparison with the comparative example with respect to pattern formation by electron beam irradiation.

Example 8
In the same manner as in Example 1, resists were prepared and coated using the compounds shown in Table 3 below to obtain a resist film. However, the film thickness was 0.40 μm.

(3) Formation of positive resist pattern The obtained resist film was subjected to pattern exposure using a KrF excimer laser stepper (FPA3000EX-5 manufactured by Canon Inc., wavelength 248 nm). The post-exposure processing was performed in the same manner as in Example 1. The pattern was evaluated as follows. The evaluation results are shown in Table 3.
(3-1) Sensitivity The cross-sectional shape of the obtained pattern was observed using a scanning electron microscope (S-4300, manufactured by Hitachi, Ltd.). The minimum irradiation energy when resolving a 0.18 μm line (line: space = 1: 1) was defined as sensitivity.
(3-2) LWR (Line Edge Roughness)
About the resist pattern obtained by carrying out similarly to the above, the line width was observed with the scanning electron microscope (S-9220 by Hitachi, Ltd.), and the fluctuation | variation (LWR) of the line width in the line width of 130 nm was observed. Using a length-measuring scanning electron microscope (SEM), the line width was detected at a plurality of positions in the measurement monitor, and the dispersion (3σ) of variations in the detected positions was used as an LWR index.
(3-3) Density dependency The line width of the dense pattern (line: space = 1: 1) and the line width of the isolated pattern in the 0.18 μm line pattern at the irradiation dose exhibiting the above sensitivity are measured, and the difference between them is measured. Sparse and dense dependence.

Examples 9 to 14 and Comparative Example 2
Using the compounds shown in Table 3, resist preparation, coating, and KrF excimer laser exposure evaluation were performed in the same manner as in Example 8 as described above. The evaluation results are shown in Table 3.

  From Table 3, it can be seen that the positive resist composition of the present invention has higher sensitivity, pattern edge roughness, and density dependency than the comparative example with respect to pattern formation by KrF excimer laser exposure.

Examples 15 to 19 and Comparative Example 3
A resist film was obtained in the same manner as in Example 1 using the compounds shown in Table 4 below. However, the resist film thickness was 0.13 μm. The obtained resist film was subjected to surface exposure using EUV light (wavelength 13 nm) while changing the exposure amount by 0.5 mJ in the range of 0 to 5.0 mJ, and further baked at 110 ° C. for 90 seconds. Thereafter, using a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution, the dissolution rate at each exposure amount was measured to obtain a sensitivity curve. In this sensitivity curve, the exposure amount when the dissolution rate of the resist is saturated was taken as sensitivity, and the dissolution contrast (γ value) was calculated from the gradient of the linear portion of the sensitivity curve. The larger the γ value, the better the dissolution contrast.
The results are shown in Table 4.

  From Table 4, it can be seen that the positive resist composition of the present invention is superior in sensitivity and high contrast as compared with the comparative example in characteristics evaluation by irradiation with EUV light.

Claims (6)

A resist composition comprising (A) a compound capable of generating an acid upon irradiation with actinic rays or radiation and (B) a resin having a repeating unit represented by the following general formula (I).

In general formula (I),
Ra represents an alkyl group.
Rb represents a hydrogen atom or a monovalent organic group.   2. The resist composition according to claim 1, wherein in the general formula (I), Rb is a group capable of leaving by the action of an acid.   The resist composition according to claim 2, wherein the group capable of leaving by the action of an acid of Rb has an alicyclic structure. The resist composition according to claim 1, wherein the resin of component (B) further has a repeating unit represented by the following general formula (A1) or (A2).

In general formula (A1),
A ₁ represents a group having a hydrogen atom, a group capable of leaving by the action of an acid, or a group decomposing by the action of an acid.
In general formula (A2),
A ₂ represents a group having a group capable of leaving by the action of an acid or a group decomposing by the action of an acid.
Rc represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group or an alkyloxycarbonyl group. In the general formula (A1), A ₁ is a resist composition according to claim 4, characterized in that a hydrogen atom.   A pattern forming method comprising: forming a resist film from the resist composition according to claim 1, exposing and developing the resist film.