JP2007206638A - Positive resist composition and pattern forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition for use in the production process of a semiconductor such as IC, in the production of a circuit substrate of liquid crystal, thermal head and the like or in other lithography processes of photo-application and a pattern forming method using the same, which are a positive resist composition improved in sensitivity, resolution, pattern profile, in-plane uniformity of line width, development defects and dissolution contrast at the same time and a pattern forming method using the same. <P>SOLUTION: The positive resist composition contains (A) a compound capable of generating an acid upon irradiation with an actinic ray or radiation and (B) a resin of which the solubility in an alkali developer increases under the action of an acid, wherein (B) the resin of which the solubility in an alkali developer increases under the action of an acid has a repeating unit derived from a monomer of a specific structure. The pattern forming method using the same is also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a positive 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 same. More specifically, the present invention relates to a positive resist composition 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 same. KrF excimer laser light The present invention relates to a positive resist composition that can be suitably used for microfabrication of a semiconductor device using electron beam or EUV light, and a pattern forming method using the same.

  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 positive resist with high sensitivity and high resolution is desired. In particular, high sensitivity is a very important issue for shortening the wafer processing time, but in the case of positive resists for electron beams and EUV, the resolution decreases when trying to achieve high sensitivity. Development of resists that simultaneously satisfy these characteristics is strongly desired. High sensitivity, high resolution, and good pattern shape are in a trade-off relationship, and it is very important how to satisfy this simultaneously.

Further, in lithography using KrF excimer laser light, it is also important to improve sensitivity, resolution, line width in-plane uniformity, and development defects at the same time, and these solutions are necessary.
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, the sensitivity, resolution, pattern shape, line width in-plane uniformity, and development defect in the ultrafine region are not improved 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

  An object of the present invention is to solve the problem of performance improvement technology in microfabrication of semiconductor elements using actinic rays or radiation, particularly KrF excimer laser light, electron beam or EUV light, and sensitivity, resolution, It is an object of the present invention to provide a positive resist composition having improved pattern shape, line width in-plane uniformity and development defect at the same time and 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 a positive resist composition containing a specific acid-decomposable resin, and have reached the present invention.
The present invention is as follows.

  (1) In a positive resist composition comprising (A) a compound capable of generating an acid upon irradiation with actinic rays or radiation, and (B) a resin whose solubility in an alkali developer is increased by the action of the acid. B) A positive resist composition, wherein the resin whose solubility in an alkaline developer is increased by the action of an acid has a repeating unit of a monomer represented by the following general formula (I).

In general formula (I),
A ₀ represents a hydrogen atom or an organic group.
Ra represents an organic group, a halogen atom, a cyano group, or a nitro group.
X represents a hydrogen atom or an organic group.
m represents an integer of 1 to 3.
n represents an integer of 0 to 3.
However, m + n ≦ 5.

(2) The positive resist composition as described in (1), wherein A ₀ in the general formula (I) is a group capable of leaving by the action of an acid.

  (3) The positive resist composition as described in (1) or (2), wherein X in the general formula (I) is a group having an alicyclic structure and leaving by the action of an acid. object.

(4) (B) A resin whose solubility in an alkaline developer is increased by the action of an acid is further a repeating unit represented by the following general formula (A1), a repeating unit represented by the general formula (A2), and The positive resist composition as described in any one of (1) to (3), which has at least one type of repeating unit selected from the repeating units represented by formula (A3).

In the general formulas (A1) to (A3),
Z represents a hydroxyl group, a halogen atom, a cyano group, a nitro group, an acyl group, or an acyloxy group. When there are a plurality of Zs, the plurality of Zs may be the same or different.
A ₁ represents a group having a cyclic carbon structure and leaving by the action of an acid. A ₁ is, when a plurality, the plurality is A ₁ may be the same or different.
Rb represents a hydrogen atom, a methyl group, a halogen atom, a cyano group or a CF ₃ group.
A ₂ represents a group capable of leaving by the action of an acid.
q represents an integer of 1 to 3.
r represents an integer of 1 to 3.
p represents an integer of 0 to 2.

  (5) A pattern forming method comprising: forming a resist film from the positive resist composition according to any one of (1) to (4); and exposing and developing the resist film.

  According to the present invention, sensitivity, resolution, pattern shape, line width in-plane uniformity, development defect, and dissolution contrast are simultaneously improved with respect to pattern formation by irradiation with actinic rays or radiation such as electron beam, KrF excimer laser light, or EUV light. In addition, a positive resist composition and a pattern forming method using the same can be provided.

  In the description of the group (atomic group) in this specification, the description which does not describe substitution and unsubstituted 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 a repeating unit of the monomer represented by the general formula (I) and having increased solubility in an alkaline developer by the action of an acid. It contains a resin (hereinafter, also referred to as “acid-decomposable resin”) having a repeating unit of the monomer represented by formula (I) and having increased solubility in an alkaline developer by the action of an acid.

In general formula (I),
A ₀ represents a hydrogen atom or an organic group.
Ra represents an organic group, a halogen atom, a cyano group, or a nitro group.
X represents a hydrogen atom or an organic group.
m represents an integer of 1 to 3.
n represents an integer of 0 to 3.
However, m + n ≦ 5.

In the general formula (I), examples of the organic group represented by A ₀ include an alkyl group and an acyl group. The alkyl group is preferably an alkyl group having 1 to 12 carbon atoms, and specific examples include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and a t-butyl group. The alkyl group for A ₀ may further have a substituent such as an alkoxy group, a cycloalkylalkyloxy group, and an alkyloxycarbonyl group. The organic group of A ₀ is a tertiary alkyl group such as t-butyl group or t-amyl group, 1 such as 1-methoxyethyl group, 1-ethoxyethyl group, 1-propoxyethyl group or 1-butoxyethyl group. -When it is an alkoxyethyl group or an alkoxymethyl group, it is eliminated by the action of an acid, a hydroxyl group is formed, and the solubility in an alkali developer increases.

  Examples of the organic group for Ra include a linear or branched alkyl group, a monocyclic or polycyclic cycloalkyl group, an aryl group, an aralkyl group, an ester group, an amide group, and a carboxyl group.

  Examples of the organic group for X include a linear or branched alkyl group (preferably having 1 to 8 carbon atoms), a monocyclic or polycyclic cycloalkyl group (preferably having 3 to 20 carbon atoms), an aryl group (preferably C6-10), an aralkyl group (preferably C7-12), an alkenyl group (preferably C2-8), etc. can be mentioned.

The organic group of X is preferably a group capable of leaving by the action of an acid.
Examples of the group capable of leaving by the action of an acid of X include tertiary alkyl groups such as t-butyl group and t-amyl group, isobornyl group, 1-butoxyethyl group, 1-isobutoxyethyl group, 1-cyclohexyl group. Examples include 1-alkoxyethyl group such as siloxyethyl group, alkoxymethyl group, tetrahydropyranyl group, tetrahydrofuranyl group, 3-oxocyclohexyl ester group, 2-methyl-2-adamantyl group, mevalonic lactone residue, etc. And those having 4 to 20 carbon atoms, and those having an alicyclic structure are preferred.

  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 structures may have a substituent.

  Below, the specific example of an alicyclic structure is shown.

  Preferred examples of the group having an alicyclic structure 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. Group, 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 group having an alicyclic structure 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. Examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. The alkyl group and the alkoxy group may have a further substituent. Examples of further substituents on the alkyl group and alkoxy group include a hydroxyl group, a halogen atom, and an alkoxy group.

  The group having an alicyclic structure and leaving by the action of an acid is preferably a group represented by the following general formula (pI) to general formula (pV).

In the general formulas (pI) to (pV),
R ₁₁ represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, or a sec-butyl group.
Z represents an atomic group necessary for forming an alicyclic hydrocarbon group together with a carbon atom.
R _{12 to} R ₁₆ each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms or an alicyclic hydrocarbon group. However, at least one of R _{12 to} R ₁₄ , or any of R ₁₅ and R ₁₆ represents an alicyclic hydrocarbon group.
R _{17 to} R ₂₁ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or an alicyclic hydrocarbon group. However, at least one of R _{17 to} R ₂₁ represents an alicyclic hydrocarbon group. In addition, any of R ₁₉ and R ₂₁ represents a linear or branched alkyl group or alicyclic hydrocarbon group having 1 to 4 carbon atoms.
R _{22 to} R ₂₅ each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or an alicyclic hydrocarbon group. However, at least one of R _{22 to} R ₂₅ represents an alicyclic hydrocarbon group. R ₂₃ and R ₂₄ may be bonded to each other to form a ring.

In general formulas (pI) to (pV), the alkyl group represented by R _{12 to} R ₂₅ may be either substituted or unsubstituted, and is a linear or branched alkyl having 1 to 4 carbon atoms. Represents a group. Examples of the alkyl group 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.
Further, the further substituent of the alkyl group includes an alkoxy group having 1 to 4 carbon atoms, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), an acyl group, an acyloxy group, a cyano group, a hydroxyl group, A carboxy group, an alkoxycarbonyl group, a nitro group, etc. can be mentioned.

Examples of the alicyclic hydrocarbon group in R _{11 to} R _{25 or} the alicyclic hydrocarbon group formed by Z and a carbon atom include those described above as the group having an alicyclic structure.

  The monomer represented by the general formula (I) is synthesized by esterifying cinnamic acid chloride and an alcohol compound in the presence of a basic catalyst such as triethylamine, pyridine or DBU in a solvent such as THF, acetone or methylene chloride. can do. A commercially available product may be used.

  Specific examples of the monomer represented by the general formula (1) are given below, but the present invention is not limited thereto.

  The acid-decomposable resin of the present invention is further selected from a repeating unit represented by the following general formula (A1), a repeating unit represented by the general formula (A2), and a repeating unit represented by the general formula (A3). It is preferable to have at least one type of repeating unit.

In the general formulas (A1) to (A3),
Z represents a hydroxyl group, a halogen atom, a cyano group, a nitro group, an acyl group, or an acyloxy group. When there are a plurality of Zs, the plurality of Zs may be the same or different.
A ₁ represents a group having a cyclic carbon structure and leaving by the action of an acid. A ₁ is, when a plurality, the plurality is A ₁ may be the same or different.
Rb represents a hydrogen atom, a methyl group, a halogen atom, a cyano group or a CF ₃ group.
A ₂ represents a group capable of leaving by the action of an acid.
q represents an integer of 1 to 3.
r represents an integer of 1 to 3.
p represents an integer of 0 to 2.

In general formula (A1), q preferably represents an integer of 1 to 2.
In the general formula (A1), the substitution position of —OH is preferably p-position, m-position, or a mixture of p-position and m-position.

  Other substituents that the benzene ring in the general formula (A1) may have include an alkyl group, a halogen atom, a carboxyl group, an alkoxy group, an acyl group, an acyloxy group, an aryloxy group, an aralkyl group, an aryl group, A cyano group, a nitro group, etc. are mentioned, Preferably it is C10 or less.

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

In the general formula (A2), examples of the group having a cyclic carbon structure of A ₁ and leaving by the action of an acid include -C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), -C (R _{36) (R 37) (OR} 39), - COO-C (R 36) (R 37) (R 38), - C (R 01) (R 02) (OR 39), - C (R 01) ( R ₀₂ ) COO-C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ) and the like.
R _{36 to} R ₃₉ each independently represents an alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, an alkenyl group which may have a substituent, or a substituent. Represents an aralkyl group which may have a substituent or an aryl group which may have a substituent. R ₃₆ and R ₃₉ may be bonded to each other to form a ring.
R ₀₁ and R ₀₂ are each independently a hydrogen atom, an alkyl group which may have a substituent, a cycloalkyl group which may have a substituent, or an alkenyl group which may have a substituent. Represents an aralkyl group which may have a substituent or an aryl group which may have a substituent.
Provided that at least one of R ₃₆ , R ₃₇ , R ₃₈ , at least one of R ₃₆ , R ₃₇ , R ₃₉ , at least one of R ₀₁ , R ₀₂ , R ₃₉ is itself Alternatively, the substituent has a cyclic carbon structure.

As the alkyl group for R _{36 to} R ₃₉ , R ₀₁ and R ₀₂ , an alkyl group having 1 to 8 carbon atoms is preferable. For example, a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, A hexyl group, 2-ethylhexyl group, an octyl group, etc. can be mentioned.
The cycloalkyl group for R _{36 to} R ₃₉ , R ₀₁ and R ₀₂ may be monocyclic or polycyclic. The monocyclic type is preferably a cycloalkyl group having 3 to 8 carbon atoms, and examples thereof include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclobutyl group, and a cyclooctyl group. As the polycyclic type, a cycloalkyl group having 6 to 20 carbon atoms is preferable. For example, an adamantyl group, norbornyl group, isobornyl group, camphanyl group, dicyclopentyl group, α-pinel group, tricyclodecanyl group, tetocyclo A dodecyl group, an androstanyl group, etc. can be mentioned. A part of carbon atoms in the cycloalkyl group may be substituted with a hetero atom such as an oxygen atom.
The aryl group of R _{36 to} R ₃₉ , R ₀₁ and R ₀₂ is preferably an aryl group having 6 to 10 carbon atoms, such as a phenyl group, tolyl group, dimethylphenyl group, 2,4,6-trimethylphenyl group. Naphthyl group, anthryl group, 9,10-dimethoxyanthryl group, and the like.
As the aralkyl group of R _{36 to} R ₃₉ , R ₀₁ and R _02, an aralkyl group having 7 to 12 carbon atoms is preferable, and examples thereof include a benzyl group, a phenethyl group, and a naphthylmethyl group.
The alkenyl group represented by R _{36 to} R ₃₉ , R ₀₁ and R ₀₂ is preferably an alkenyl group having 2 to 8 carbon atoms, and examples thereof include a vinyl group, an allyl group, a butenyl group, and a cyclohexenyl group.
Examples of the substituent that R _{36 to} R ₃₉ , R ₀₁ and R ₀₂ may have include an alkyl group, a cycloalkyl group, an aryl group, an amino group, an amide group, a ureido group, a urethane group, a hydroxy group, and a carboxy group. , Halogen atoms, alkoxy groups, cycloalkyloxy groups, aryloxy groups, aralkyloxy groups, thioether groups, acyl groups, acyloxy groups, alkoxycarbonyl groups, cyano groups, nitro groups, and the like.

The group having a cyclic carbon structure of A ₁ and leaving by the action of an acid is particularly preferably a group represented by the following general formula (X1) or general formula (X2).

In general formula (X1),
R ₁ and R ₂ each independently represents a hydrogen atom or an alkyl group.
R ₃ and R ₄ each independently represents a hydrogen atom, an alkyl group or a cycloalkyl group.
Za represents a cycloalkyl group or an aryl group. The cycloalkyl group may have a bridged structure.
r represents an integer of 0 to 20.

In general formula (X2),
R ₁ and R ₂ each independently represents a hydrogen atom or an alkyl group.
W represents a divalent linking group.
Y represents a group selected from —O—, —OCO—, —COO—, —O—CH ₂ —, —NHCO—, —CONH—, —S—, —SO ₂ — and —SO ₃ —.
Za represents a cycloalkyl group or an aryl group. The cycloalkyl group may have a bridged structure.

The alkyl group as R ₁ and R _{2 in the} general formula (X1) is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, or an n-propyl group. , Isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group and the like.
At least one of R ₁ and R ₂ is preferably a linear or branched alkyl group having 1 to 4 carbon atoms.

The alkyl group as R ₃ and R ₄ may be linear or branched. As a linear alkyl group, Preferably it is C1-C30, More preferably, it is 1-20, for example, a methyl group, an ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl. Group, n-heptyl group, n-octyl group, n-nonyl group, n-decanyl group and the like. As a branched alkyl group, Preferably it is C3-C30, More preferably, it is 3-20, for example, i-propyl group, i-butyl group, t-butyl group, i-pentyl group, t-pentyl group, i-
Examples include hexyl group, t-hexyl group, i-heptyl group, t-heptyl group, i-octyl group, t-octyl group, i-nonyl group, t-decanoyl group and the like.
The cycloalkyl group as R ₃ and R ₄ preferably has 3 to 30 carbon atoms, more preferably 3 to 20, for example, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl. Group, cyclononyl group, cyclodecanoyl group and the like.

  In the general formula (X1), the aryl group of Za is preferably an aryl group having 6 to 30 carbon atoms, more preferably 3 to 20 carbon atoms, and a hydrocarbon atom, a nitrogen atom, a sulfur atom, A heteroaryl group having a heteroatom such as an oxygen atom can be mentioned. Examples of the aryl group composed of a hydrocarbon include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a pyrenyl group. Examples of the heteroaryl group include a pyrrole group, an indole group, a carbazole group, a furan group, and a thiophene group. The aryl group for Za is particularly preferably a phenyl group.

The cycloalkyl group of Za may be monocyclic, polycyclic, or bridged. For example, the cycloalkyl group may have a bridged structure. 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 to 30, and particularly preferably 6 to 25.
Preferred examples of the cycloalkyl group of Za include 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 can be mentioned. More preferred are 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.

R _{1 to} R ₄ and Za may further have a substituent.
Examples of the substituent for R _{1 to} R ₄ and Za include alkyl group, cycloalkyl group, aryl group, aralkyl group, halogen atom, hydroxyl group, alkoxy group, cycloalkyloxy group, aryloxy group, aralkyloxy group carboxyl group, alkoxy group A carbonyl group is mentioned. 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 cycloalkyl group is preferably a cycloalkyl group having 6 to 25 carbon atoms, such as an adamantyl group, decalin group, norbornyl group, cedrol group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecanyl group, cyclododecanyl group, A tricyclodecanyl group etc. can be mentioned. The aryl group is preferably an aryl group having 6 to 14 carbon atoms. For example, a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a biphenyl residue (a group formed by losing one hydrogen atom from a biphenyl group) And p-terphenyl residue (a group formed by losing one hydrogen atom from a p-terphenyl group). The aralkyl group is preferably an aralkyl group having 7 to 12 carbon atoms, and examples thereof include a benzyl group, a phenethyl group, and a naphthylmethyl group. Preferred examples of the alkoxy group include those having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. The cycloalkyloxy group is preferably a cycloalkyloxy group having 6 to 25 carbon atoms, such as an adamantyloxy group, a decalinoxy group, a norbornyloxy group, a cedroloxy group, a cyclohexyloxy group, a cycloheptyloxy group, or a cyclooctyl group. Examples thereof include an oxy group, a cyclodecanyloxy group, a cyclododecanyloxy group, and a tricyclodecanyloxy group. The aryloxy group is preferably an aryloxy group having 6 to 14 carbon atoms, and examples thereof include a phenyloxy group, a naphthyloxy group, and an anthryloxy group. The aralkyloxy group is preferably an aralkyloxy group having 7 to 12 carbon atoms, and examples thereof include a benzyloxy group, a phenethyloxy group, and a naphthylmethyloxy group. The substituents that the alkyl group, cycloalkyl group, aryl group, aralkyl group, alkoxy group, cycloalkyloxy group, aryloxy group, aralkyloxy group may further have include a hydroxyl group, a halogen atom, and an alkyl group (preferably C1-C4), an alkoxy group (preferably C1-C4) etc. can be mentioned.

  Specific examples of the group represented by the general formula (X1) are shown below, but the present invention is not limited thereto.

In formula (X2), the alkyl group as R ₁ and R ₂ are the same as those of the alkyl group as R ₁ and R ₂ in the general formula (X1).
The divalent linking group for W preferably has 1 to 10 carbon atoms, and includes, for example, a linear, branched or cyclic alkylene group, an arylene group, a heteroarylene group, an aralkylene group, and —S—, —C ( ═O) —, —N (R ₇ ) —, —SO—, —SO ₂ —, —CO ₂ —, —N (R ₇ ) SO ₂ — or a divalent group obtained by combining two or more of these groups. Can be mentioned. Here, R ₇ can include a hydrogen atom or an alkyl group (specific examples of the alkyl group include those similar to the above R ₁ ).
Za is the same as Za in the general formula (X1).
In General Formula (X2), it is preferable that at least _one of R ₁ and R ₂ is a linear or branched alkyl group having 2 to 4 carbon atoms.

  Specific examples of the group represented by the general formula (X2) are shown below, but the present invention is not limited thereto.

In the general formula (A2), examples of the halogen atom for Z include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
The acyl group of Z is preferably an acyl group having 1 to 8 carbon atoms, and examples thereof include a formyl group, an acetyl group, a propionyl group, a butyryl group, a valeryl group, a pivaloyl group, and a benzoyl group.
The acyloxy group of Z is preferably an acyloxy group having 2 to 8 carbon atoms. For example, an acetoxy group, a propionyloxy group, a butyllioxy group, a valeryloxy group, a pivaloyloxy group, a hexanoyloxy group, an octanoyloxy group, a benzoyloxy group, etc. Can be mentioned.
Z may be further substituted with a halogen atom or the like.

  Specific examples of the repeating unit represented by formula (A2) are shown below, but the present invention is not limited thereto.

The group capable of leaving by the action of the general formula in the (A3), the A ₂ acid, for example, t- butyl group, a tertiary alkyl group, isobornyl group such as t-amyl group, 1-butoxyethyl group, 1-alkoxyethyl group such as 1-isobutoxyethyl group, 1-cyclohexyloxyethyl group, alkoxymethyl group, tetrahydropyranyl group, tetrahydrofuranyl group, 3-oxocyclohexyl ester group, 2-methyl-2-adamantyl group, Examples include mevalonic lactone residues, which preferably have 4 to 20 carbon atoms, and preferably have an alicyclic structure.

In the general formula (A3), the group having an alicyclic structure of A ₂ and leaving by an acid is preferably, for example, a group represented by the general formula (pI) to the general formula (pV).

The group having the alicyclic structure of A _{2 in} the general formula (A3) and desorbed by an acid in the general formula (A3) from the point that the variation in pattern size during observation with a scanning electron microscope is small (SEM resistance) is shown below. It is particularly preferred that

In the above formula,
R ₂₆ and R ₂₇ each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms.

  In the general formula (A3), examples of the halogen atom for Rb include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  Hereinafter, although the specific example of the monomer corresponding to the repeating unit represented by general formula (A3) is given, this invention is not limited to this.

  The acid-decomposable resin preferably further has a repeating unit represented by the following general formula (A4).

In general formula (A4),
Rf represents a hydrogen atom, a methyl group, a cyano group, a halogen atom, or a perfluoroalkyl group having 1 to 4 carbon atoms.
n represents an integer of 0 to 4.
Rg represents a group that is not decomposed by the action of an acid.

  Rg represents a group that is not decomposed by the action of an acid (also referred to as an acid stabilizing group), and specifically, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an acyl group, an alkylamide group, an arylamide Examples include a methyl group, an arylamide group, an alkylcarbonyloxy group, an alkyloxy group, a cycloalkyloxy group, and an aryloxy group. The acid stabilizing group is preferably an alkyl group, an acyl group, an alkylamide group, an alkylcarbonyloxy group, an alkyloxy group, a cycloalkyloxy group, or an aryloxy group, more preferably an alkyl group, an acyl group, or an alkylamide group. An alkylcarbonyloxy group, an alkyloxy group, a cycloalkyloxy group, and an aryloxy group.

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

  Although the specific example of the repeating unit represented by general formula (A4) below is given, it is not limited to these.

The acid-decomposable resin of the present invention is a resin whose solubility in an alkali developer is increased by the action of an acid. In any repeating unit, a group that decomposes by the action of an acid to produce an alkali-soluble group ( Acid-decomposable group).
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 (R ₀₁ ) ( R ₀₂ ) (OR ₃₉ ) and the like.
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.
The acid-decomposable resin of the present invention may have an acid-decomposable group in the repeating unit represented by the general formula (I), the general formula (A2) or the general formula (A3), or other repeating units. You may have in a unit.
Preferable examples of the acid-decomposable group 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-.

In the acid-decomposable resin, the content of the repeating unit by the monomer represented by formula (I) is preferably 5 to 50 mol%, more preferably 10 to 40 mol%, based on all repeating units.
The content of the repeating unit represented by the general formula (A1) in the acid-decomposable resin is preferably 10 to 75 mol%, more preferably 20 to 60 mol% in all repeating units.
The content of the repeating unit represented by the general formula (A2) in the acid-decomposable resin is preferably 10 to 50 mol%, more preferably 20 to 40 mol% in all repeating units.
The content of the repeating unit represented by the general formula (A3) in the acid-decomposable resin is preferably 10 to 50 mol%, more preferably 20 to 40 mol% in all repeating units.
The content of the repeating unit represented by the general formula (A4) in the acid-decomposable resin is preferably 0 to 40 mol%, more preferably 10 to 30 mol% in all repeating units.
The content of the repeating unit having an acid-decomposable group in the acid-decomposable resin is preferably 10 to 50 mol%, more preferably 15 to 40 mol% in all repeating units.

  In order to maintain good developability for an alkali developer, the acid-decomposable resin is copolymerized with an appropriate other polymerizable monomer so that an alkali-soluble group such as a phenolic hydroxyl group or a carboxyl group can be introduced. Alternatively, in order to improve the film quality, other hydrophobic polymerizable monomers such as alkyl acrylate and alkyl methacrylate may be copolymerized.

  The weight average molecular weight (Mw) of the acid-decomposable resin is preferably in the range of 1,000 to 15,000, and 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.

The acid-decomposable resin may be used alone or in combination of two or more.
The total amount of the acid-decomposable resin is usually 10 to 96% by mass, preferably 15 to 96% by mass, and particularly preferably 20 to 95% by mass with respect to the total solid content of the positive resist composition. %.

  Specific examples of the acid-decomposable resin are given below, but the present invention is not limited thereto.

[2] (A) Compound capable of generating an acid upon irradiation with actinic rays or radiation A compound capable of generating an acid upon irradiation with actinic rays or radiation contained in the positive 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 of these actinic rays or radiation, or a compound in which the compound is introduced into the main chain or side chain of the polymer, for example, US Pat. No. 3,849,137, German Patent No. 3914407. JP, 63-26653, JP 55-164824, JP 62-69263, JP 63-146038, JP 63-163452, JP 62-153853, The compounds described in 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, most 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.
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 .

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.

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 positive 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 positive 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 positive resist composition of the present invention is preferably 0.01 to 10% by mass, more preferably 0.03 to 5% by mass, based on the total solid content of the composition. Particularly preferably, it is 0.05 to 3% by 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] Organic Basic Compound In the present invention, it is preferable to use an organic basic compound from the viewpoint of improving performance such as resolution and improving storage stability. As the organic basic compound, a compound containing a nitrogen atom (nitrogen-containing basic compound) is more preferable.
A preferable organic basic compound in the present invention is a compound having a stronger basicity than phenol.
As a preferable chemical environment, the following general formulas (A) to (E) can be exemplified. The general 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 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, piperazine, N- (2-aminoethyl) piperazine N- (2-aminoethyl) piperi 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, pyrimidine, 2,4-diaminopyrimidine, 4,6-dihydroxypyrimidine, 2-pyrazoline, Examples include, but are not limited to, 3-pyrazoline, N-aminomorpholine, and N- (2-aminoethyl) morpholine.
These nitrogen-containing basic compounds are used alone or in combination of two or more.

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 organic basic compound in the composition is preferably (total amount of acid generator) / (organic 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) / (organic 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 composition of the present invention.
These surfactants may be added alone or in some combination.

The surfactant is any one of fluorine and / or silicon surfactants (fluorine surfactants and silicon surfactants, surfactants containing both fluorine atoms and silicon atoms), or It is preferable to contain 2 or more types.
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 positive resist composition (excluding the solvent).

[5] Other components The positive 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 positive 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, the pattern forming 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, etc.). A resist pattern is formed by applying a resist composition, forming a resist film, and then irradiating actinic rays or radiation such as KrF excimer laser light, electron beam, EUV light, etc., heating, developing, rinsing and drying. Can be formed.

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 alkaline 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 (1))
Acetoxystyrene, styrene, and t-butyl- (p-acetoxycinnamate) were charged at a ratio (molar ratio) of 55/20/25 and dissolved in tetrahydrofuran to prepare 100 mL of a solution having a solid content concentration of 20% by mass. 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 and again V-65 was 1 mol%
Added and 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.
The composition ratio of the polymer determined from C ¹³ NMR was 58/20/22 (molar ratio). Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 9,500.
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 10,000.

  Resins (2) to (22) whose structures were previously exemplified, shown in Table 1 below, were synthesized in the same manner as in Synthesis Example 1.

  In addition, resin (CR-1) of a comparative example is p-hydroxystyrene-styrene-t-butyl acrylate copolymer (molar ratio 60/20/20), a weight average molecular weight 10,000, and dispersion degree 2.28.

  The sulfonic acid generator and carboxylic acid generator used in the examples of the present invention were 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 (1) 0.93g
Sulfonic acid generator B-2 0.065g
Carboxylic acid generator C-2 0.005g
Is dissolved in 8.8 g of propylene glycol monomethyl ether acetate, 0.001 g of D-1 (see below) as an organic 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) Production 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, the substrate 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) Resolving power The resolving power was defined as the limiting resolving power (the line and space were separated and resolved) at the irradiation dose showing the above sensitivity.
(2-3) Pattern shape The cross-sectional shape of the 0.15 μm line pattern at the irradiation dose showing the above sensitivity was observed using a scanning electron microscope (S-4300, manufactured by Hitachi, Ltd.).

Examples 2 to 14 and Comparative Example 1
Resist preparation / coating and electron beam exposure evaluation were performed in the same manner as in Example 1 except that the components shown in Table 2 below were used. The evaluation results are shown in Table 2.

Abbreviations in the table are shown below.
[Organic basic compounds]
D-1: tri-n-hexylamine D-2: 2,4,6-triphenylimidazole D-3: tetra- (n-butyl) ammonium hydroxide [other components (surfactant)]
W-1: Fluorosurfactant, Megafac F-176 (Dainippon Ink Chemical Co., Ltd.)
W-2: Fluorine / silicone surfactant, MegaFac R08 (manufactured by Dainippon Ink & Chemicals, Inc.)
W-3: Silicon-based surfactant, siloxane polymer KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.)

  From Table 2, it can be seen that the positive resist composition of the present invention has higher sensitivity, higher resolution and better pattern shape than the comparative example with respect to pattern formation by electron beam irradiation.

Example 15
A resist film was obtained in the same manner as in Example 1 except that the components shown in Table 3 below were used. However, the film thickness was 0.35 μm.

(3) Formation of positive 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.
(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 0.26 μm line (line: space = 1: 1) was defined as sensitivity.
(3-2) Resolving power The resolving power was defined as the limiting resolving power (line and space are separated and resolving) at the irradiation amount showing the above sensitivity.
(3-3) Line width in-plane uniformity evaluation A resist pattern obtained by exposing the entire surface of an 8-inch wafer with an exposure amount reproduced by a 130 nm (pitch 260 nm) Line and Space pattern was randomly measured at 50 points on the entire surface of the wafer. The 3σ was defined as in-plane uniformity.
(3-4) Development Defect Evaluation The entire surface of the 8-inch wafer was exposed with an exposure amount that reproduces a 130 nm (pitch 260 nm) Line and Space pattern to obtain a resist pattern. The development defect was measured using an intelligent line monitor 2360 manufactured by KLA Tencor.

Examples 16 to 23 and Comparative Example 2
Using the components shown in Table 3, resist preparation / coating and KrF excimer laser exposure evaluation were performed in exactly the same manner as in Example 15. The evaluation results are shown in Table 3.

  From Table 3, the positive resist composition of the present invention has higher sensitivity and higher resolution than the compound of the comparative example with respect to pattern formation by KrF excimer laser exposure, and is excellent in pattern shape and density dependency. I understand.

Examples 24-26 and Comparative Example 3
A resist film was obtained in the same manner as in Example 1 except that the components shown in Table 4 below were used. 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 composition of the comparative example in the property evaluation by irradiation with EUV light.

Claims (5)

In a positive resist composition comprising (A) a compound that generates an acid upon irradiation with actinic rays or radiation, and (B) a resin whose solubility in an alkali developer is increased by the action of the acid. A positive resist composition, wherein the resin whose solubility in an alkaline developer is increased by the action of has a repeating unit of a monomer represented by the following general formula (I):

In general formula (I),
A ₀ represents a hydrogen atom or an organic group.
Ra represents an organic group, a halogen atom, a cyano group, or a nitro group.
X represents a hydrogen atom or an organic group.
m represents an integer of 1 to 3.
n represents an integer of 0 to 3.
However, m + n ≦ 5. 2. The positive resist composition according to claim 1, wherein A ₀ in the general formula (I) is a group capable of leaving by the action of an acid.   3. The positive resist composition according to claim 1, wherein X in the general formula (I) is a group having an alicyclic structure and leaving by the action of an acid. (B) Resins whose solubility in an alkaline developer is increased by the action of an acid are further a repeating unit represented by the following general formula (A1), a repeating unit represented by the general formula (A2), and a general formula ( The positive resist composition according to claim 1, comprising at least one type of repeating unit selected from repeating units represented by A3).

In the general formulas (A1) to (A3),
Z represents a hydroxyl group, a halogen atom, a cyano group, a nitro group, an acyl group, or an acyloxy group. When there are a plurality of Zs, the plurality of Zs may be the same or different.
A ₁ represents a group having a cyclic carbon structure and leaving by the action of an acid. A ₁ is, when a plurality, the plurality is A ₁ may be the same or different.
Rb represents a hydrogen atom, a methyl group, a halogen atom, a cyano group or a CF ₃ group.
A ₂ represents a group capable of leaving by the action of an acid.
q represents an integer of 1 to 3.
r represents an integer of 1 to 3.
p represents an integer of 0 to 2.   A pattern forming method comprising: forming a resist film from the positive resist composition according to claim 1; and exposing and developing the resist film.