JP2007248514A - Positive resist composition and pattern-forming method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition superior in dissolution contrast by solving problems of performance improvement technology in micro-fabrication of a semiconductor element using an active optical beam or radiation, in particular, a KrF excimer laser beam, an electron beam or EUV light, and simultaneously satisfying high sensitivity, high resolution, excellent pattern shape and excellent density independence, and to provide a pattern-forming method using it. <P>SOLUTION: The positive resist composition contains (A) a compound generating acid by irradiation of an active optical beam or radiation, and (B) a resin of a specific structure increasing dissolubility to alkaline developer by action of acid. The pattern-forming method using it 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 particularly, the present invention relates to a positive 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 same. KrF excimer laser light, electron The present invention relates to a positive resist composition that can be suitably used for microfabrication of a semiconductor device using a line and 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 formation technology, and a highly sensitive positive resist is desired. In particular, high sensitivity is a very important issue in order to shorten the wafer processing time. However, in positive resists for electron beams and EUV, resolution and pattern shapes are required when seeking high sensitivity. The development of resists that satisfy these characteristics at the same time 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, high resolution, good pattern shape, and good density dependence are in a trade-off relationship, and how to satisfy them simultaneously is very important.

Furthermore, in lithography using KrF excimer laser light, it is also important to satisfy high sensitivity, high resolution, good pattern shape, and good density dependency at the same time. is there.
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 present situation is that high sensitivity, high resolution, good pattern shape, and good density dependence are not satisfied at the same time in the ultrafine region.

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 high resolution. The present invention provides a positive resist composition that simultaneously satisfies the above properties, good pattern shape, and good density dependence, and has a 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-mentioned problems can be solved by using a resin having a specific structure, and have reached the present invention.

  The present invention is as follows.

  (1) 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 alkaline developer is increased by the action of the acid, B) A resin whose solubility in an alkaline developer is increased by the action of an acid has a repeating unit represented by the following general formula (I) and has a crosslinked structure that crosslinks at least two main chains. A positive resist composition having an acid-decomposable bond that decomposes by the action of an acid in the cross-linked structure to generate an alkali-soluble group in the side chain of each main chain.

In general formula (I),
Ra represents a hydrogen atom or an organic group. When there are two Ras, the two Ras may be the same or different.
Rb represents a hydrogen atom or an organic group.
n represents an integer of 0 to 2.

  (2) In the general formula (I), at least one organic group in Ra and Rb is an organic group that is eliminated by the action of an acid, and the positive type as described in (1) Resist composition.

  (3) A cross-linked structure in which an organic group that is released by the action of an acid is bonded to an organic group that is released by the action of an acid that is bonded to the side chain of another main chain to cross-link the two main chains. The positive resist composition as described in (2), which is formed.

  (4) (B) The resin whose solubility in an alkaline developer is increased by the action of an acid further has a repeating unit represented by the following general formula (A1) (1) to (3 The positive resist composition according to any one of the above.

In general formula (A1),
A ₁ represents a hydrogen atom or an organic group. When two A ₁ are present, the two A ₁ may be the same or different.
m represents an integer of 1 to 2.

  (5) (B) A resin whose solubility in an alkaline developer is increased by the action of an acid, and further has a repeating unit of (meth) acrylate in which the atom bonded to the ester group is a tertiary carbon atom. The positive resist composition according to any one of (1) to (4).

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

  According to the present invention, a positive resist with high sensitivity, high resolution, excellent pattern shape and density dependency, and good dissolution contrast with respect to pattern formation by irradiation with an electron beam, KrF excimer laser light, EUV light or the like. A composition and a pattern forming method using the composition can be provided.

Hereinafter, 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) A resin whose solubility in an alkaline developer is increased by the action of an acid, having a repeating unit represented by the following general formula (I), and crosslinking at least two main chains A resin having two acid-decomposable bonds that are decomposed by the action of an acid to generate an alkali-soluble group in the side chain of each main chain in the crosslinked structure. A resin whose solubility in an alkaline developer is increased by the action of an acid, having a repeating unit represented by the following general formula (I), and having a crosslinking structure that crosslinks at least two main chains. And a resin having an acid-decomposable bond (hereinafter also referred to as “resin (B)”) that decomposes by the action of an acid to generate an alkali-soluble group in the side chain of each main chain.

In general formula (I),
Ra represents a hydrogen atom or an organic group. When there are two Ras, the two Ras may be the same or different.
Rb represents a hydrogen atom or an organic group.
n represents an integer of 0 to 2.

Examples of the organic group for Ra in the general formula (I) include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkoxycarbonyl group. The alkyl group is preferably a linear or branched alkyl group having 1 to 15 carbon atoms, specifically, methyl group, ethyl group, propyl group, butyl group, amyl group, hexyl group, peptyl group, octyl group, Nonyl group, decyl group, etc. can be mentioned. The alkyl group may have a substituent, and examples of the alkyl group having a substituent include a trifluoroalkyl group, a trichloroalkyl group, a hydroxyalkyl group, and a cyanoalkyl group. The cycloalkyl group is preferably a cycloalkyl group having 3 to 30 carbon atoms, and examples thereof include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, and a cyclodecanoyl group. . The aryl group is preferably an aryl group having 6 to 14 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthryl 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. The alkoxycarbonyl group is preferably an alkoxycarbonyl group having 2 to 15 carbon atoms. Moreover, the organic group may have a hetero atom in the middle. Specifically, an alkoxyalkyl group (preferably 2 to 15 carbon atoms), a cycloalkoxyalkyl group (preferably 4 to 15 carbon atoms), an acylalkyl group (preferably 3 to 15 carbon atoms), an acyloxyalkyl group (preferably Includes 3 to 15 carbon atoms). The organic group having a hetero atom may further have a substituent such as a cycloalkyl group, an aryl group, a cycloalkoxy group, an aryloxy group, a cycloalkylaryloxy group, and an arylcycloalkyloxy group.
The organic group of Ra is preferably an organic group that is eliminated by the action of an acid. Examples of the organic group that is eliminated by the action of an acid of Ra include —C (Rx) (Ry) —O—Rz, a tertiary alkyl group, and a t-butoxycarbonyl group. Here, Rx and Ry each independently represent a hydrogen atom or an alkyl group (preferably having 1 to 6 carbon atoms). Rz represents an organic group. Rx and Ry are preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom, a methyl group, an ethyl group, or an isopropyl group. The organic group as Rz is preferably an organic group having 2 to 25 carbon atoms (more preferably, an alkyl group, a cycloalkyl group, or an aryl group). The organic group as Rz is preferably an alkyl group having 2 to 20 carbon atoms. The alkyl group as Rz may have a substituent. Examples of the substituent include an alkoxy group having 2 to 12 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, and an aryloxy group having 2 to 20 carbon atoms. preferable.
The organic group that is eliminated by the action of an acid of Ra is preferably bonded to the organic group that is eliminated by the action of an acid bonded to another main chain to form a crosslinked structure.

As an organic group of Rb, a C1-C20 alkyl group, a C3-C20 cycloalkyl group, etc. are mentioned, for example, Preferably, a C1-C12 alkyl group and a C3-C12 are mentioned. A cycloalkyl group; Examples of the alkyl group include 1 to 1 carbon atoms such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a t-butyl group, a pentyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Ten are preferred. Cycloalkyl groups include adamantyl, noradamantyl, decalin, tricyclodecanyl, tetracyclododecanyl, norbornyl, cedrol, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecanyl, cyclodecane A dodecanyl group is preferable, and 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 are more preferable. Examples of the substituent that the alkyl group and cycloalkyl group 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 organic group of Rb is preferably an organic group that is eliminated by the action of an acid. Examples of the organic group eliminated by the action of the acid of Rb include —C (R ₃₆ ) (R ₃₇ ) (R ₃₈ ), —C (R ₃₆ ) (R ₃₇ ) (OR ₃₉ ), and the like. it can.
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.
The alkyl group of R36 to R39 is preferably an alkyl group having 1 to 8 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, a hexyl group, and an octyl group. Can do.
The cycloalkyl group of R _{36 to} R ₃₉ 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 cyclobutyl group, a cyclopentyl group, a cyclohexyl 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, tetracyclododecyl group. Group, androstanyl group and the like. 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 is preferably an aryl group having 6 to 10 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthryl group.
The aralkyl group of R _{36 to} R ₃₉ 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.
The alkenyl group of R36 to R39 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.
R _{36 to} R ₃₉ may have a substituent. Examples of the substituent that R _{36 to} R ₃₉ 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 hydroxyl group, a carboxyl group, a halogen atom, Examples thereof include an alkoxy group, a thioether group, an acyl group, an acyloxy group, an alkoxycarbonyl group, a cyano group, and a nitro group.
The organic group that is eliminated by the action of the acid of Rb is preferably combined with the organic group that is eliminated by the action of the acid bonded to the other main chain to form a crosslinked structure.

  The resin (B) is preferably an organic group in which at least one organic group out of Ra and Rb is eliminated by the action of an acid. The resin (B) is a resin in which at least one of Ra and Rb is an organic group that is eliminated by the action of an acid, so that the solubility in an alkali developer is increased by the action of the acid.

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

  Resin (B) has a cross-linked structure that cross-links at least two main chains, and decomposes by the action of an acid in the cross-linked structure to generate an alkali-soluble group in the side chain of each main chain. Have

  A cross-linked structure having an acid-decomposable group (hereinafter referred to as “cross-linked structure (B) ) ”) Can be formed, for example, by bonding together organic groups that are eliminated by the action of an acid in the repeating unit forming each main chain.

  Examples of the repeating unit having an organic group capable of leaving by the action of an acid include repeating units represented by the following general formulas (Ia), (IIa), and (IIIa).

In general formula (Ia):
Raa represents a hydrogen atom or an organic group. When there are two Raa, the two Raa may be the same or different.
Rba represents a hydrogen atom or an organic group.
n represents an integer of 0 to 2.
However, one of Raa and Rba represents an organic group that is eliminated by the action of an acid.
In general formula (IIa):
A _1a represents a hydrogen atom or an organic group. When two A ₁ are present, the two A ₁ may be the same or different.
m represents an integer of 1 to 2.
However, at least one of A _1a represents an organic group that is eliminated by the action of an acid.
In general formula (IIIa):
Rca represents an organic group that is eliminated by the action of an acid.
R _1a represents a hydrogen atom, an alkyl group, a halogen atom or a cyano group.

The organic group of Raa in the general formula (Ia) is the same as the organic group of Ra in the general formula (I).
The organic group released by the action of Ra acid is the same as the organic group released by the action of Ra acid.
The organic group of Rba is the same as the organic group of Rb in the general formula (I).
The organic group released by the action of the acid of Rba is the same as the organic group released by the action of the acid of Rb.

In the general formula (IIa), an organic group of A _1a is in the below general formula (A1), is similar to the organic group of A _1.
The organic group that is eliminated by the action of the acid of A _{1a is} the same as the organic group that is eliminated by the action of the acid of Ra in the general formula (I).

In the general formula (IIIa), the organic group that is eliminated by the action of the acid of Rca is the same as the organic group that is eliminated by the action of the acid of Rb in the general formula (I).
R _1a is in the below formula (II), it is similar to the R _1a.

Examples of the bond of the organic group that is eliminated by the action of an acid that forms the crosslinked structure (B) include, for example, Raa in the general formula (Ia) that forms one main chain and the general formula that forms the other main chain. Bonding with Raa in (Ia), Rba in General Formula (Ia) forming one main chain and Rba in General Formula (Ia) forming the other main chain, Bonding of Raa in general formula (Ia) forming the main chain and Rba in general formula (Ia) forming the other main chain, in general formula (Ia) forming one main chain A bond between Raa and A _1a in the general formula (IIa) forming the other main chain, Rba in the general formula (Ia) forming one main chain and a general formula forming the other main chain ( coupling between in a _1a to IIa), and in Raa in formula (Ia) to form the backbone of one A bond with Rca in formula (IIIa) that forms one main chain, Rba in formula (Ia) that forms one main chain and a general formula (IIIa) that forms the other main chain binding to at Rca, coupled with the general formula (IIa) in at a _1a forming the main chain backbone in formula (IIa) in a _1a and the other to form a one, the backbone of one Rca in the general formula (IIIa) forming the other main chain and Rca in the general formula (IIIa) forming the other main chain, A _1a in the general formula (IIa) forming one main chain And a bond with Rca in the general formula (IIIa) forming the other main chain.
That is, examples of the combination of the repeating units forming the crosslinked structure (B) include, for example, the repeating unit represented by the general formula (Ia) that forms one main chain and the general formula (Ia) that forms the other main chain. A combination of the repeating unit represented by the general formula (Ia) that forms one main chain and the repeating unit represented by the general formula (IIa) that forms the other main chain A combination of the repeating unit represented by the general formula (Ia) that forms one main chain and the repeating unit represented by the general formula (IIIa) that forms the other main chain, and the general that forms one main chain A combination of the repeating unit represented by the formula (IIa) and the repeating unit represented by the general formula (IIa) that forms the other main chain, and the repeating represented by the general formula (IIIa) that forms one main chain Unit and others In combination with the repeating unit represented by the general formula (IIIa) that forms the main chain, and the general formula that forms the other main chain with the repeating unit represented by the general formula (IIa) that forms one main chain ( Examples include combinations with repeating units represented by IIIa).

  Hereinafter, although the specific example of the crosslinked structure (B) which bridge | crosslinked two repeating units which form a different principal chain is shown, this invention is not limited to this.

In the above example,
Rb represents a hydrogen atom or an organic group and is the same as Rb in the general formula (Ia).
R _1a represents a hydrogen atom, an alkyl group, a halogen atom or a cyano group, and is the same as R _{1a in} formula (IIIa).
L _1a represents —CH (Rd ₁ ) —O—Rd ₂ —. In the formula, Rd ₁ represents a hydrogen atom, an alkyl group (preferably 1 to 5 carbon atoms), a cycloalkyl group (preferably 3 to 10 carbon atoms) or an aryl group (preferably 6 to 10 carbon atoms), Rd ₂ represents an alkylene group (preferably having 1 to 5 carbon atoms), a cycloalkylene group (preferably having 3 to 10 carbon atoms) or an arylene group (preferably having 6 to 10 carbon atoms).
L _1b represents —C (Rd ₃ ) (Rd ₄ ) —Rd ₅ —. In the formula, Rd ₃ and Rd ₄ are each independently an alkyl group (preferably having 1 to 5 carbon atoms), a cycloalkyl group (preferably having 3 to 10 carbon atoms) or an aryl group (preferably having 6 to 10 carbon atoms). Rd ₅ represents an alkylene group (preferably having 1 to 5 carbon atoms), a cycloalkylene group (preferably having 3 to 10 carbon atoms) or an arylene group (preferably having 6 to 10 carbon atoms).
L ₂ represents a single bond or a divalent linking group. Examples of the divalent linking group for L ₂ include an alkylene group (preferably having 1 to 5 carbon atoms), a cycloalkylene group (preferably having 3 to 10 carbon atoms), an arylene group (preferably having 6 to 10 carbon atoms), and A divalent linking group in which these are combined can be exemplified.

In the above specific examples, —O—L _1a —, that is, —O—CH (Rd ₁ ) —O—Rd ₂ —, is decomposed by the action of an acid to form an alkali-soluble group (hydroxyl group) on the side chain of the main chain. Is an acid-decomposable bond.
—C (═O) —OL 1 _b —, that is, —C (═O) —O—C (Rd ₃ ) (Rd ₄ ) —Rd ₅ — is decomposed by the action of an acid to the main chain side. It is an acid-decomposable bond that forms an alkali-soluble group (carboxyl group) in the chain.

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

In general formula (A1),
A ₁ represents a hydrogen atom or an organic group. When two A ₁ are present, the two A ₁ may be the same or different.
m represents an integer of 1 to 2.

In the general formula (A1), the organic group represented by A _{1 is the same as} the organic group represented by Ra in the general formula (I).

  Specific examples of the repeating unit represented by the general formula (A1) include the upper and lower repeating units and the following repeating units in the specific example (Ba1).

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

In general formula (II):
Rc represents a hydrogen atom or an organic group.
R _1a represents a hydrogen atom, an alkyl group, a halogen atom or a cyano group.

The organic group represented by Rc in the general formula (II) is the same as the organic group represented by Rd in the general formula (I).
The alkyl group represented by R _1a is preferably an alkyl group having 1 to 5 carbon atoms and may be substituted with a halogen atom, a hydroxyl group or the like.

  The repeating unit represented by the general formula (II) is a repeating unit of (meth) acrylate in which the atom bonded to the ester group is a tertiary carbon atom, that is, a repeating unit represented by the general formula (II): R1a is preferably a hydrogen atom or a methyl group, and Rc is preferably an organic group that is eliminated by the action of an acid.

  Specific examples of the repeating unit represented by the general formula (II) include the upper and lower repeating units and the following repeating units in the specific example (Ba5).

The resin (B) preferably has a repeating unit having a group (acid-decomposable group) that is decomposed by the action of an acid to increase the solubility in an alkali developer.
Since the resin (B) has a repeating unit having an acid-decomposable group, the increase in solubility in an alkali developer due to the action of an acid is further promoted.
Examples of the acid-decomposable group include a group in which a hydrogen atom such as a hydroxyl group or a carboxyl group is substituted with a group capable of leaving by the action of an acid.

In the resin (B), the content of the repeating unit represented by the general formula (I) is preferably 10 to 60 mol%, and more preferably 15 to 40 mol% in all repeating units.
In the resin (B), the content of the repeating unit having the crosslinked structure (B) is preferably 2 to 20 mol%, more preferably 3 to 10 mol% in all repeating units.
In the resin (B), the content of the repeating unit represented by the general formula (A1) is preferably 20 to 90 mol%, more preferably 40 to 80 mol% in all repeating units.
In the resin (B), the content of the repeating unit represented by the general formula (I1) is preferably from 10 to 50 mol%, more preferably from 20 to 40 mol%, based on all repeating units.
In the resin (B), the content of the repeating unit having an acid-decomposable group is preferably 5 to 50 mol%, more preferably 10 to 30 mol%.

  Resin (B), for example, after dissolving the monomer giving the above repeating unit in an organic solvent such as THF, ethyl acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methoxybutanol, etc., under a nitrogen atmosphere and heating conditions, After adding a radical polymerization initiator such as peroxide or azo and reacting with stirring, the polymer is polymerized, and then reprecipitated in a poor solvent with respect to the polymer such as hexane and methanol, and filtered to obtain a powder. And then re-dissolved in an organic solvent such as THF, and then reacted with a crosslinking agent such as divinyl ether. In addition, it is preferable to use the dropping polymerization method in which the monomer dissolved in the solvent and the radical polymerization initiator are added together or separately in the polymerization reaction solution.

  The content of the resin (B) in the positive resist composition is preferably 80 to 99% by mass, more preferably 85 to 99% by mass, based on the solid content, and 90 to 98% by mass. Even more preferably.

  Hereinafter, although the specific example of resin (B) is given, this invention is not limited to this.

[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, 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 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] 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 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 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 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 (10))
Acetoxystyrene and 2-methyl-2-adamantyl cinnamate were charged at a ratio (molar ratio) of 83/17 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 dropping, 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.
The composition ratio of the polymer determined from C ¹³ NMR was 85/15 (molar ratio). Moreover, the weight average molecular weight of standard polystyrene conversion calculated | required by GPC measurement was 10500.
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 9000.
20 g of the (4-hydroxystyrene)-(2-methyl-2-adamantyl cinnamate) copolymer obtained above is dissolved in 100 ml of THF, 3 g of cyclohexanedimethanol divinyl ether is added, and p-toluenesulfone is added. 100 mg of acid was added and stirred at room temperature for 3 hours. After neutralizing by adding 300 mg of triethylamine, the mixture was poured into 2 L of distilled water with stirring and reprecipitated. The obtained solid was filtered and then dried under reduced pressure at room temperature. The composition ratio of the obtained resin (1) was 5/81/14 (molar ratio), and the weight average molecular weight was 12000.

  Table 1 below shows the resin (B) copolymer composition ratio (molar ratio) and weight average molecular weight used in the examples.

Example 1
(1) Preparation and coating of positive resist Resin (1) 0.93g
0.07 g of acid generator (B-2)
Is dissolved in 8.8 g of propylene glycol monomethyl ether acetate, further 0.003 g as a basic compound (D-1, see below), and Megafac F176 as a surfactant (manufactured by Dainippon Ink & Chemicals, Inc.) 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 resist 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) 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 amount showing the above sensitivity was observed using a scanning electron microscope (S-4300, manufactured by Hitachi, Ltd.), and was rectangular, slightly tapered, Three-point evaluation of the taper was performed.
(2-4) Density dependency 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 8.5 μC / cm ² , the resolving power was 0.10 μm, the pattern shape was rectangular, and the density dependency was 10 nm, which was very good.

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

Abbreviations in the table are as follows.
〔resin〕

[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.)

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

Example 8
In the same manner as in Example 1, resist preparation and coating were performed using the components 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.
(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) 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) Pattern shape The cross-sectional shape of the 0.18 μm line pattern at the irradiation amount showing the above sensitivity was observed using a scanning electron microscope (S-4300, manufactured by Hitachi, Ltd.), and was rectangular, slightly tapered, Three-point evaluation of the taper was performed.
(3-4) 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 showing the above sensitivity are measured, and the difference between them is measured. Sparse and dense dependence.

As a result of Example 8, the sensitivity was 38 mJ / cm ² , the resolving power was 0.15 μm, the pattern shape was rectangular, and the density dependency was 11 nm, which was very good.

Examples 9 to 14 and Comparative Example 2
Resist preparation / coating and KrF excimer laser exposure evaluation were performed in the same manner as in Example 8 using the components shown in Table 3 below. 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 15 to 19 and Comparative Example 3
A resist film was obtained in the same manner as in Example 1 using the components 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 composition of the comparative example in the property evaluation by irradiation with EUV light.

Claims (6)

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, comprising (B) an acid The resin whose solubility in an alkaline developer is increased by the action of has a repeating unit represented by the following general formula (I) and has a cross-linking structure that cross-links at least two main chains. A positive resist composition having an acid-decomposable bond that decomposes by the action of an acid in the structure and generates an alkali-soluble group in the side chain of each main chain.
In general formula (I),
Ra represents a hydrogen atom or an organic group. When there are two Ras, the two Ras may be the same or different.
Rb represents a hydrogen atom or an organic group.
n represents an integer of 0 to 2.   2. The positive resist composition according to claim 1, wherein in the general formula (I), at least one organic group of Ra and Rb is an organic group which is eliminated by the action of an acid. .   An organic group that is released by the action of an acid is combined with an organic group that is released by the action of an acid that is bonded to the side chain of another main chain to form a crosslinked structure that crosslinks the two main chains. The positive resist composition according to claim 2, wherein: (B) The resin whose solubility in an alkali developer is increased by the action of an acid further has a repeating unit represented by the following general formula (A1): The positive resist composition as described.
In general formula (A1),
A ₁ represents a hydrogen atom or an organic group. When two A ₁ are present, the two A ₁ may be the same or different.
m represents an integer of 1 to 2.   (B) The resin whose solubility in an alkaline developer is increased by the action of an acid, further has a repeating unit of (meth) acrylate in which the atom bonded to the ester group is a tertiary carbon atom. Item 5. The positive resist composition according to any one of Items 1 to 4.   A pattern forming method comprising: forming a resist film with the positive resist composition according to claim 1, exposing and developing the resist film.