JP2000235263A - Positive type resist composition and acid dissociable group-containing monomer used in same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a low-cost positive type resist composition for ArF excellent in sensitivity, resolution and electron beam resistance by incorporating a specified polymer and a compound that generates an acid when irradiated with radiation. SOLUTION: The resist composition contains a polymer containing at least units of the formula and a compound that generates an acid when irradiated with radiation. In the formula, R is H or a lower alkyl, R1 is a >=2C alkyl and (n) is 0 or 1. The units of the formula are derived from a polycyclic olefin such as bicyclo[2,2,1]-2-heptene(norbornene) or tetracyclo[4,4,0,12.5,17.10]-3- dodecene and the polymer contains the units in the principal chain and has a 1->=2C alkyl-1-cyclohexyloxycarbonyl group in the 5- or 8-position on each ring. The resist composition forms a resist pattern excellent in dry etching resistance without using an expensive polycyclic hydrocarbon group at the acid dissociable group part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a chemically amplified positive resist composition and an acid-labile group-containing monomer used therefor. More specifically, a chemical compound for an ArF excimer laser characterized by blending a polycyclic olefin monomer having a 1-alkyl (2 or more carbon atoms) -1-cyclohexyl ester as an acid dissociable group and a base resin synthesized therefrom. The present invention relates to an amplification-type positive resist composition.

[0002]

2. Description of the Related Art At present, a chemically amplified resist for a KrF (248 nm) excimer laser has already been put to practical use for forming a resist pattern of 0.30 μm or less. On the other hand, lithography processes using an ArF (193 nm) excimer laser of 0.15 μm or less have been actively developed, and many proposals have been made on resists for ArF. For example, JP-A-9-230595,
JP-A-9-244247 proposes a resist using a polycyclic polyolefin resin having an acid dissociable group such as a tert-butyloxycarbonyl group and a 1-methylcyclohexyloxycarbonyl group. Further W
O97 / 33198, JP-A-10-10739,
JP-A-10-111569 discloses a resist using a resin obtained by copolymerizing a norbornene having an acid dissociable group such as a tert-butyloxycarbonyl group or a 1-methyl-1-cyclohexyloxycarbonyl group with maleic anhydride. Has been proposed.

[0003]

However, the acid-dissociable groups proposed in these publications are not sufficiently dissociable by the acid generated from the acid generator. However, there is a problem that a resist using a resin having the same has insufficient sensitivity. Further, the resolution and the cross-sectional shape of the resist pattern cannot be said to be sufficient, and improvement is desired. Further, the 1-methyl-1-cyclohexyloxycarbonyl group has a problem that 1-methyl-1-hydroxycyclohexane as a raw material for synthesizing it is very expensive and industrialization is difficult. Also, JP-A-10-130340 and JP-A-10-15386
No. 4, JP-A-10-198035, JP-A-10-198035
Japanese Patent Application Laid-Open Nos. 0-207058, 10-207070, 10-218941, and 10-207.
JP-A-218947 and the like also propose a positive resist for ArF, but do not particularly propose a positive resist having an acid-dissociable group.

On the other hand, Japanese Patent Application Laid-Open No. H10-161313
The publication describes that high sensitivity can be achieved by bonding a lower alkyl group having 2 or more carbon atoms such as an ethyl group or a propyl group to a carbon atom at the 1-position of an alicyclic hydrocarbon group. ing. Further, in paragraph number 0029 of the publication,
As an alicyclic hydrocarbon group, it is described that a condensed ring such as adamantane is particularly preferable because a monocyclic group such as a cyclohexyl group has insufficient dry etching resistance. However, adamantane is very expensive and difficult to industrialize. In the semiconductor industry in recent years, the provision of inexpensive materials has become more important industrially than before. Further, the publication specifically discloses a polymer having an alicyclic hydrocarbon group on the side chain of the acrylic resin, but such an acrylic resin having an alicyclic hydrocarbon group on the side chain is: There is a problem that electron beam resistance is low. Electron beam resistance means that the profile shape of a resist pattern in the manufacture of a semiconductor device is SEM
(Scanning electron microscope), and the resist pattern size is measured by a high-resolution FEB length measuring device (for example, “S-8820” manufactured by Hitachi, Ltd.). There is a problem that the resist pattern is deteriorated due to the influence and a dimensional change occurs in the resist pattern size.

Accordingly, the present invention provides a resist pattern which is excellent in sensitivity, resolution and cross-sectional shape of a resist pattern, is inexpensive, and has a small dimensional change of the resist pattern size even under the influence of an electron beam and is excellent in electron beam resistance. An object of the present invention is to provide a positive resist composition for ArF that can be formed and an acid-dissociable group-containing monomer used therefor.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that an acid-dissociable group is 1-alkyl (having 2 or more carbon atoms).
The object of the present invention has been achieved by using a base resin synthesized using a novel polycyclic olefin monomer having a -1-cyclohexyloxycarbonyl group.

The invention of claim 1 provides (A) a polymer containing at least a unit represented by the following general formula (I) and (B)
A positive resist composition containing a compound that generates an acid upon irradiation with radiation.

[0008]

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(Wherein R represents a hydrogen atom or a lower alkyl group, R ¹ represents an alkyl group having 2 or more carbon atoms, and n represents 0 or 1). The positive resist composition according to claim 1, which is a copolymer of a unit represented by the general formula (I) and another copolymerizable monomer. The invention according to claim 3 is the positive resist composition according to claim 2, wherein the other copolymerizable monomer is at least one selected from maleic anhydride and a polycyclic olefin. The invention according to claim 4 is the positive resist composition according to claim 3, wherein the other copolymerizable monomer is maleic anhydride. In the invention according to claim 5, the unit of the other copolymerizable monomer is at least one unit derived from a polycyclic olefin represented by the following general formula (II). It is a type resist composition.

[0010]

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(Wherein R and n are the same as above, and R ² is a hydrogen atom, a carboxyl group or an alkyloxycarbonyl group having 1 to 10 carbon atoms and having at least one hydroxyl group). Is a polymer in which the component (A) contains at least a unit represented by the following general formula (III).
It is a positive resist composition of the above.

[0012]

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(Wherein R, R ¹ and n are the same as described above) In the invention of claim 7, the component (A) is represented by at least the above general formula (III) and the following general formula (IV) 7. The positive resist composition according to claim 6, which is a polymer containing units.

[0014]

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(Wherein R is the same as above, R ³ is an alkyl group having 1 to 10 carbon atoms having a hydroxyl group, and m is 0 or 1). The positive resist composition according to claim 5, which is a polymer represented by the general formula (V) containing at least three units.

[0016]

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(Wherein R, R ¹ and n are the same as above, and R ⁴ is an alkyloxycarbonyl group having 1 to 10 carbon atoms and having at least one hydroxyl group). The positive resist composition according to claim 1, wherein R ¹ is a lower alkyl group having 2 or more carbon atoms. Claim 1
0 of invention is a positive resist composition according to claim 7 or 9, wherein R ³ is a lower monohydroxy alkyl group or a lower dihydroxy alkyl group. An eleventh aspect of the present invention is the positive resist composition according to the ninth aspect, wherein R ¹ is an ethyl group. According to a twelfth aspect of the present invention, R ³ is 2-
The positive resist composition according to claim 10, which is a hydroxypropyl group. The invention of claim 13 further comprises 0.01 to 5% by weight of an organic carboxylic acid or an oxo acid of phosphorus or a derivative thereof based on (A).
13. The positive resist composition according to any one of claims 1 to 12. The invention of claim 14 further comprises (A)
2. The composition according to claim 1, wherein the content is 0.01 to 5% by weight based on the weight.
4. The positive resist composition according to any one of 3.
The positive resist composition according to any one of claims 1 to 14, wherein the bile acid and the ester of an acid-dissociable group are further blended in an amount of 1 to 100% by weight based on (A). is there. The invention of claim 16 is the positive resist composition according to claim 15, wherein the bile acid ester is a tert-butyl ester of cholic acid, deoxycholic acid, ursocholic acid and lithocholic acid. The invention of claim 17 is an acid dissociable group-containing monomer represented by the following general formula (VI).

[0018]

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(Wherein R and R ¹ are as defined above)

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Component (A) The component (A) of the present invention is a polymer containing at least a unit represented by the general formula (I).

[0021]

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(Wherein R represents a hydrogen atom or a lower alkyl group, R ¹ represents an alkyl group having 2 or more carbon atoms, and n is 0 or 1)

The unit represented by the general formula (I) is bicyclo
[2.2.1] -2-heptene (norbornene), tetracyclo [4.4.0.1 ^2.5. 1. ^7.10 ] -3-Dodecene having a unit derived from a polycyclic olefin such as a dodecene in the main chain of the polymer, and having 5- or 8-position alkyl-1- having at least 2 carbon atoms in the main chain of the polymer. Cyclohexyl (the acid dissociable group of the present invention) has an oxycarbonyl group.

The component (A) of the present invention has a unit derived from such a polycyclic olefin in the main chain and has an oxycarbonyl (ester) group containing an acid dissociable group of the present invention on its ring. In addition, a resist pattern having excellent dry etching resistance can be formed without using an expensive polycyclic hydrocarbon group such as an adamantyl group for the acid dissociable group. Also, it has excellent electron beam resistance. Further, since the inexpensive acid dissociable group portion of the present invention can be used at the same time, an inexpensive positive resist composition can be provided. Furthermore, since the acid dissociable group of the present invention has excellent acid dissociation properties, the sensitivity, the resolution and the cross-sectional shape of the resist pattern are improved.

In the unit represented by the general formula (I), R
Is a hydrogen atom or a lower alkyl group such as a methyl group, an ethyl group or a propyl group. The monomer forming the unit of the general formula (I) is a known reaction between (meth) acrylic acid-alkyl-1-cyclohexyl ester having 2 or more carbon atoms and cyclopentadiene or dicyclopentadiene.
It can be synthesized by the s-Alder reaction. R is preferably a hydrogen atom or a methyl group since a monomer forming the unit of the general formula (I) is obtained by such a reaction. R ¹
Is not particularly limited as long as it is an alkyl group having 2 or more carbon atoms, but is preferably a lower alkyl group such as an ethyl group, a propyl group, and a butyl group. By using such a lower alkyl group for R ¹ , the acid dissociation property is improved, so that the sensitivity, the resolution, and the cross-sectional shape of the resist pattern are improved.

The component (A) may be a polymer containing at least 1 to 80 mol%, preferably 15 to 50 mol%, of the unit represented by the above general formula (I). Copolymers with monomers are preferred. As the unit of the other copolymerizable monomer, a known compound having an ethylenic double bond can be arbitrarily used according to the purpose. As the compound having such an ethylenic double bond, in particular, at least one selected from maleic anhydride and polycyclic olefin is preferable because of excellent resolution and resist pattern cross-sectional shape. Examples of the polycyclic olefin, bicyclo [2.2.1] -2-heptene (norbornene), tetracyclo [4.4.0.1 ^2.5.
1. ^7.10 ] Polycyclic olefins such as] -3-dodecene are mentioned. Further, the ring may have various substituents such as a functional group for improving alkali solubility and a functional group for improving adhesion between the substrate and the resist film.

The monomer unit derived from such a copolymerizable polycyclic olefin is preferably at least one polycyclic olefin unit represented by the following general formula (II).

[0028]

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Wherein R and n are the same as described above, and R ² is a hydrogen atom, a carboxyl group or an alkyloxycarbonyl group having 1 to 10 carbon atoms and having at least one hydroxyl group.

When R ² is a hydrogen atom, it is an unsubstituted polycyclic olefin unit and improves dry etching resistance. When R ² is a carboxyl group, alkali solubility is improved. In the case of an alkyloxycarbonyl group having at least one hydroxyl group and having 1 to 10 carbon atoms, the adhesion between a silicon wafer or a silicon wafer provided with an inorganic film and the resist layer is improved. The alkyloxycarbonyl group having at least one hydroxyl group is preferably an alkyloxycarbonyl group having one or two hydroxyl groups and having 1 to 10 carbon atoms. Specific examples include a hydroxymethyloxycarbonyl group, a hydroxyethyloxycarbonyl group, a hydroxypropyloxycarbonyl group, a hydroxybutyloxycarbonyl group, a 2,3-dihydroxybutyloxycarbonyl group, and a hydroxypentyloxycarbonyl group. Is preferably a 2-hydroxypropyloxycarbonyl group.

In the case of the copolymer of the general formulas (I) and (II),
The unit of the general formula (I) is 1 to 80 mol%, preferably 10
The range of from 50 to 50 mol% and the unit of the general formula (II) is from 20 to 99 mol%, preferably from 50 to 90 mol%, from the viewpoint of improving the adhesion and the resolution. One or more units represented by the general formula (II) can be copolymerized at the same time or two or more at the same time.
The polymer represented by the general formula (V) containing two units is preferable.

[0032]

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Wherein R, R ¹ and n are the same as above, and R ⁴ is an alkyloxycarbonyl group having at least one hydroxyl group and having 1 to 10 carbon atoms.

In the case of the copolymer of the general formula (V), x is 1 to
80 mol%, preferably 10 to 50 mol%, y is 1 to 4
The range of 5 mol%, preferably 1 to 40 mol%, and the range of z is 1 to 20 mol%, preferably 5 to 10 mol% is preferable in consideration of alkali solubility, adhesion and resolution.

The monomer of the unit represented by the general formula (II) is the same as the monomer of the unit represented by the general formula (I) except that R ² is a hydrogen atom. A hydroxyalkyl ester of (meth) acrylic acid and cyclopentadiene or dicyclopentadiene can be synthesized by a known Diels-Alder reaction. When R ² is a hydrogen atom, a polycyclic olefin having no substituent such as norbornene may be used.

When the other copolymerizable monomer is maleic anhydride, a polymer containing at least a unit represented by the following general formula (III) is preferred.

[0037]

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Wherein R, R ¹ and n are as defined above.

Further, it is preferable to use a polymer containing units represented by at least the above general formula (III) and the following general formula (IV) because the adhesion to a substrate is improved.

[0040]

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Wherein R is the same as above, R ³ is an alkyl group having at least one hydroxyl group and having 1 to 10 carbon atoms, and m is 0 or 1.

The unit represented by the general formula (III) is obtained by dissolving the polycyclic olefin monomer represented by the general formula (VI) and maleic anhydride in a suitable organic solvent such as dioxane or tetrahydrofuran. Benzoyl peroxide, 2,2 '
-It can be obtained by adding a radical polymerization initiator such as azoisobutyronitrile, acetyl peroxide, lauryl peroxide and copolymerizing. General formula (VI)
When n = 0, the polycyclic olefin monomer represented by the formula is 1-alkyl (having 2 or more carbon atoms) -1-hydroxycyclohexane (hereinafter simply referred to as cyclohexane derivative).
After synthesizing an ester of (meth) acrylic halide and this, it can be easily synthesized with cyclopentadiene by Diels-Alder reaction. The chemical reaction formula is shown below.

[0043]

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Since cyclohexane derivatives are not commercially available, they can be synthesized by a nucleophilic addition reaction using cyclohexanone and a Grignard reagent or alkyl lithium, which is a known reaction for obtaining an alcohol from a ketone. The reaction formula is shown below.

[0045]

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(In the formula, R ⁵ is an alkyl group having 2 or more carbon atoms.)

The cyclohexane derivative is obtained by a nucleophilic addition reaction using cyclohexanone and a metal alkynyl such as lithium acetylide or sodium acetylide.
-Alkynyl-1-hydroxycyclohexanol can also be synthesized through a first step of obtaining it, followed by a second step of hydrogenating it. At this time, 1-alkynyl-
Since 1-hydroxycyclohexanol is a commercially available product easily available at low cost, it can be synthesized only in the second step.

The latter two-step synthesis method using metal alkynyl is preferred because the number of reaction steps is increased, but high yield is obtained without by-products. In particular, since the method of hydrogenating 1-alkynyl-1-hydroxycyclohexanol can easily obtain 1-alkyl-1-hydroxycyclohexanol at low cost,
High industrial value is preferable. This synthesis procedure is shown below.

[0049]

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(R ⁶ is a hydrogen atom or an alkyl group)

In the case of n = 2, the polycyclic olefin monomer represented by the general formula (VI) is obtained by converting an esterified product of a cyclohexanone derivative and acrylic acid or methacrylic acid into cyclopentadiene as in the case of n = 1. Can be synthesized by a Diels-Alder reaction with dicyclopentadiene which is a dimer of

In the unit represented by the general formula (IV),
Is the same as in the general formula (I). Also, R ³
Is a functional group for improving the adhesion between the silicon wafer or the silicon wafer provided with the inorganic film and the resist layer, and is not particularly limited as long as it is an alkyl group having at least one hydroxyl group. One or two alkyl groups having 1 to 10 carbon atoms are preferred. Specifically, a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, a hydroxybutyl group, a dihydroxybutyl group, a hydroxypentyl group and the like are preferable, and a 2-hydroxypropyl and a 2,3-dihydroxybutyl group are particularly preferable. The monomer of the unit represented by the general formula (IV) is obtained by converting a hydroxyalkyl ester of (meth) acrylic acid with cyclopentadiene or dicyclopentadiene in the same manner as the unit represented by the general formula (II).
It can be obtained by performing an s-Alder reaction.

The copolymerization ratio of maleic anhydride and polycyclic olefin monomer in the general formula (III) or (IV) is theoretically 50 mol% each. However, in actuality, copolymerization between maleic anhydride and polycyclic olefin monomers also occurs.
0-60 mol%, 40-60 mol% of units derived from polycyclic olefin monomers.

In the case of the copolymer of the general formulas (III) and (IV), the unit of the general formula (III) is 40 to 90 mol%, preferably 50 to 80 mol%, and the unit of the general formula (IV) is 10
It is 60 mol%, preferably 20 to 50 mol%. When the unit of the general formula (III) is less than these ranges, the sensitivity is lowered, and when it is too large, the adhesion to the substrate is poor. In addition, in addition to the units represented by the general formulas (II), (III), and (IV), conventionally known monomers for the base resin of the ArF positive resist may be copolymerized as necessary. The weight average molecular weight of the component (A) of the present invention is from 2,000 to 1
The range is 5,000, preferably 3,000 to 6,000.

(B) Component In the present invention, as the component (B), a known acid generator for a chemically amplified resist can be used and is not particularly limited. Preferably, the anion is an onium salt of a fluoroalkylsulfonic acid ion having 1 to 10 carbon atoms. As the cation of the onium salt, phenyliodonium which may be substituted with a lower alkyl group such as methyl group, ethyl group, propyl, n-butyl group, tert-butyl or methoxy group, ethoxy group or Sulfonium. The anion is a fluoroalkylsulfonic acid ion in which part or all of the hydrogen atoms of an alkyl group having 1 to 10 carbon atoms are fluorinated. As the number of carbon atoms increases and the fluorination rate (the ratio of fluorine atoms in the alkyl group) decreases, the strength of the sulfonic acid decreases, so that all the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are fluorinated. Preferred are fluoroalkylsulfonic acids. Specifically, trifluoromethanesulfonate or nonafluorobutanesulfonate of diphenyliodonium, trifluoromethanesulfonate or nonafluorobutanesulfonate of bis (4-tert-butylphenyl) iodonium, trifluoromethanesulfonate or nonafluorobutanesulfonate of triphenylsulfonium, (4-
Methylphenyl) sulfonium trifluoromethanesulfonate or nonafluorobutanesulfonate. Of these, bis (4-tert-butylphenyl) iodonium methanesulfonate or nonafluorobutanesulfonate is preferred. These are 1
Species or two or more species may be used simultaneously.

The component (B) is 0.1% of the component (A).
-20% by weight, preferably 1-10% by weight.

The composition of the present invention may contain various additives other than those described above, if necessary. Examples of the additives include organic carboxylic acids, oxo acids of phosphorus or derivatives thereof, organic amines, esters of bile acids and acid dissociable groups, and the like.

Examples of the organic carboxylic acid include, but are not particularly limited to, saturated or unsaturated aliphatic carboxylic acids, alicyclic carboxylic acids, and aromatic carboxylic acids. Examples of the saturated aliphatic carboxylic acid include monovalent or polyvalent carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid. Examples of the unsaturated aliphatic carboxylic acid include acrylic acid, crotonic acid, isocrotonic acid, 3-butenoic acid, methacrylic acid, 4-pentenoic acid, propiolic acid, 2-butyric acid, maleic acid, fumaric acid, acetylene carboxylic acid, and the like. No. Examples of the alicyclic carboxylic acid include 1,1-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and 1,1-cyclohexyldiacetic acid. Can be As the aromatic carboxylic acid, p-hydroxybenzoic acid, o-hydroxybenzoic acid, 2-hydroxy-3-
Aromatic carboxylic acids having a substituent such as a hydroxyl group such as nitrobenzoic acid, phthalic acid, terephthalic acid and isophthalic acid, a nitro group, a carboxyl group and the like can be mentioned.

Specific examples of the oxo acid of phosphorus or a derivative thereof include phosphoric acid, phosphoric acid such as phosphoric acid, phosphorous acid, di-n-butyl phosphate, and diphenyl phosphoric acid; Derivatives, phosphonic acid, phosphonic acid dimethyl ester, phosphonic acid di-n
Derivatives such as butyl esters, phenylphosphonic acids, phosphonic acid diphenyl esters, phosphonic acid dibenzyl esters and the like, and derivatives thereof such as phosphinic acids, phenylphosphinic acid and the like; Examples include, but are not limited to:

Of these, saturated aliphatic carboxylic acids such as malonic acid and succinic acid are preferred because of their high transmittance to ArF laser light and excellent resolution.

Examples of the organic amine include, but are not limited to, aliphatic amines, aromatic amines, and heterocyclic amines. As aliphatic amines,
Diethylamine, triethylamine, n-propylamine, di-n-propylamine, tri-n-propylamine, triisopropanolamine, isopropylamine, tributylamine, tripentylamine, triethanolamine, dipropanolamine, tripropanolamine, etc. No. As the aromatic amine, benzylamine, aniline, N-methylaniline, N, N-
Examples include dimethylaniline, o-methylaniline, m-methylaniline, p-methylaniline, N, N-diethylaniline, diphenylamine, di-p-tolylamine and the like. Examples of the heterocyclic amine include pyridine, o-methylpyridine, o-ethylpyridine, 2,3-dimethylpyridine, 4-ethyl-2-methylpyridine, 3-ethyl-4-methylpyridine and the like. Among these,
Aliphatic amines such as tripentylamine are preferable because of their high transmittance to ArF laser light and excellent resist pattern shape.

The mixing ratio of the organic carboxylic acid or the oxo acid of phosphorus or a derivative thereof is 0.01% with respect to the component (A).
-5% by weight, preferably 0.02-0.2% by weight. Within this range, the resolution and sensitivity are improved, which is preferable. The mixing ratio of the organic amine to the component (A)
It is in the range of 0.01 to 5% by weight, preferably 0.02 to 0.2% by weight. Within this range, the resist pattern shape and sensitivity are improved, which is preferable.

Esters of bile acids and acid dissociable groups are known as dissolution inhibitors for positive resists for ArF and are not particularly limited. The ester includes, but is not limited to, tert-butyl ester, bile acid, tetrahydropyranyl ester, ethoxyethyl ester and the like of bile acids selected from cholic acid, deoxycholic acid, ursocholic acid, lithocholic acid and the like. The ester has high transparency to an ArF excimer laser, and the acid dissociable group is dissociated by the action of an acid generated from an acid generator. Therefore, the ester is used as needed to improve the contrast of a resist pattern. The mixing ratio is 1 to 1 with respect to the component (A).
It is 100% by weight, preferably 5 to 20% by weight.

The composition of the present invention may further contain, if necessary, a compatible additive such as an antihalation agent.

The positive photoresist composition of the present invention is preferably used in the form of a solution obtained by dissolving the above-mentioned components in an appropriate solvent. Examples of such a solvent include solvents used in conventional positive photoresist compositions, for example, ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone and 2-heptanone; ethylene glycol, propylene glycol , Diethylene glycol, ethylene glycol monoacetate, propylene glycol monoacetate, diethylene glycol monoacetate, or polyhydric alcohols such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof; such as dioxane Cyclic ethers; and ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate,
Esters such as ethyl pyruvate, methyl methoxypropionate and ethyl ethoxypropionate can be mentioned. These may be used alone or as a mixture of two or more.

One example of a preferred method of using the composition of the present invention is as follows. First, on a substrate such as a silicon wafer,
Apply the solution of the positive resist composition with a spinner or the like,
Dry to form a photosensitive layer, and then expose through a patterned photomask. Next, this is heated after exposure (PEB), and then developed with a developing solution, for example, an alkaline aqueous solution such as an aqueous solution of 1 to 10% by weight of tetramethylammonium hydroxide (TMAH). A faithful image (resist pattern) can be obtained. In order to further enhance the resolution of the resist pattern, an antireflection film may be interposed between the substrate and the photosensitive layer obtained by using the composition of the present invention.

[0067]

The present invention will be further described below with reference to examples and comparative examples. Production Example 1 (Synthesis of polycyclic olefin monomer) 128 g of 1-ethyl-1-hydroxycyclohexane and 120 g of triethylamine were added to tetrahydrofuran 600
The mixture was stirred while cooling in an ice bath, and 91 g of acrylic acid chloride was added dropwise thereto over 10 minutes. Then, the temperature was slowly returned to room temperature, and the mixture was further stirred for 24 hours.
After thoroughly washing the reaction solution with water until neutral, tetrahydrofuran is removed with a rotary evaporator,
95 g of 1-ethyl-1-cyclohexyl acrylate (52% yield) was obtained. Subsequently, 91 g of the obtained 1-ethyl-1-cyclohexyl acrylate was stirred while cooling in an ice bath, and 35 g of cyclopentadiene obtained by heating and thermally decomposing dicyclopentadiene at 40 ° C.
It was added dropwise over 0 minutes. After completion of the dropwise addition, the mixture was further stirred for 12 hours. This reaction solution was 1 mmHg, 115-117
Distillation under reduced pressure was performed under the condition of ° C. to obtain a compound having the following structural formula.

[0068]

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Et represents an ethyl group. The yield was 119 g (96% yield). Proton NM
Analytical data for R: 0.8 ppm, 1.2-1.7 pp
m, 1.9 ppm, 2.2 ppm, 2.9 ppm, 3.
2 ppm, 6.0 ppm, 6.2 ppm; FTI
The analytical data of R is: 2972 cm ^-1 , 2936 cm ^-1 , 2
863 cm ^-1 , 2726 cm ^-1 , 1449 cm ^-1 , 133
6 cm ^-1, it is 1271cm ^-1; the compound from the above analytical data were identified.

Production Example 2 (Synthesis of Polymer 1) 31 g of the polycyclic olefin monomer obtained in Production Example 1 and 12.25 g of maleic anhydride were dissolved in 43 g of dioxane, and azobisisobutyronitrile was used as a reaction initiator. 4.
3 g was added, and a polymerization reaction was performed at 70 ° C. for 10 hours. After completion of the reaction, the operation of pouring the reaction product into 1 liter of n-heptane to precipitate a polymer was repeated twice. The obtained copolymer was dried under reduced pressure at room temperature. Thus, a copolymer represented by the following general formula was obtained. The yield of this copolymer was 26 g, the weight average molecular weight was 4,300, and the degree of dispersion was 1.4.

[0071]

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Production Example 3 (Synthesis of Polymer 2) The polycyclic olefin monomer 24.8 obtained in Production Example 1
g, 4.9 g of polycyclic olefin monomer obtained by Diels-Alder reaction of 2-hydroxypropyl acrylate with cyclopentadiene and 12.25 g of maleic anhydride
Was dissolved in 42 g of dioxane, and 4.2 g of azobisisobutyronitrile was added as a reaction initiator, followed by a polymerization reaction at 70 ° C. for 10 hours. After completion of the reaction, the operation of pouring the reaction product into 1 liter of n-heptane to precipitate a polymer was repeated twice. The obtained copolymer was dried under reduced pressure at room temperature. Thus, a copolymer represented by the following general formula was obtained. The yield of this copolymer was 26 g, the weight average molecular weight was 4,700, and the dispersity was 1.4.

[0073]

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Note that x and y were 80 mol% and 20 mol%, respectively.

Comparative Production Example 1 (Synthesis of Polymer 3) 29.25 g of polycyclic olefin monomer obtained by Diels-Alder reaction of 1-methyl-1-cyclohexyl acrylate with cyclopentadiene, 12.2 maleic anhydride
5 g was dissolved in 42 g of dioxane, and 4.2 g of azobisisobutyronitrile was added as a reaction initiator.
The polymerization reaction was performed for 0 hours. After completion of the reaction, the operation of pouring the reaction product into 1 liter of n-heptane to precipitate a polymer was repeated twice. The obtained copolymer was dried under reduced pressure at room temperature. Thus, a copolymer represented by the following general formula was obtained. The yield of this copolymer was 24 g, the weight average molecular weight was 4,800, and the dispersity was 1.6.

[0076]

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Comparative Production Example 2 (Synthesis of Polymer 4) 23.4 g of polycyclic olefin monomer obtained by Diels-Alder reaction of 1-methyl-1-cyclohexyl acrylate with cyclopentadiene, 2-hydroxypropyl acrylate Was dissolved in 41 g of dioxane, and 4.9 parts of azobisisobutyronitrile were added as a reaction initiator, and 4.9 parts of polycyclic olefin monomer obtained by Diels-Alder reaction with cyclopentadiene were added to 41 g of dioxane. The polymerization reaction was performed at 70 ° C. for 10 hours. After the reaction,
The operation of pouring the reaction product into 1 liter of n-heptane to precipitate a polymer was repeated twice. The obtained copolymer was dried under reduced pressure at room temperature. Thus, a copolymer represented by the following general formula was obtained. The yield of this copolymer is 24 g.
And the weight average molecular weight was 5100 and the dispersity was 1.6.
Met.

[0078]

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Note that x ′ and y ′ were 80 mol% and 20 mol%, respectively.

Example 1 100 parts by weight of the polymer 1 obtained in Production Example 2, 2 parts by weight of triphenylsulfonium trifluoromethanesulfonate,
A positive resist solution was obtained by dissolving 10 parts by weight of tert-butyl ester of cholic acid, 0.05 part by weight of malonic acid and 0.1 part by weight of tripentylamine in 570 parts by weight of propylene glycol monomethyl ether acetate. Next, this resist solution was applied on a silicon wafer provided with an organic anti-reflection film (“DUV-30” (trade name, manufactured by Brewer Science)) at a film thickness of 1000 ° using a spinner, and then 150 ° C. on a hot plate. Then, a resist layer having a thickness of 0.5 μm was formed. Next, after selectively irradiating an ArF excimer laser (193 nm) with an ArF exposure apparatus (manufactured by Nikon Corporation), PEB treatment was performed at 140 ° C. for 90 seconds, and then a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 30 seconds. It was developed with a paddle, washed with water for 30 seconds and dried. 0.18 formed by such an operation
line and space of μm is 1: mJ / cm ² as sensitivity exposure time that is formed in one (energy) was measured in units, it was 16 mJ / cm ^2. When the cross-sectional shape of the resist pattern at that time was observed with an SEM photograph, it was rectangular. In addition, a 0.15 μm line and space was resolved as the limit resolution. When the novolak was set to 1, the film loss per unit time was determined as the dry etching resistance, and it was 1.2 (the smaller the numerical value, the higher the dry etching resistance). ). As electron beam resistance, a high-resolution FEB length measuring device “S” manufactured by Hitachi, Ltd.
When the resist pattern was treated for 60 seconds with "-8820" to check whether the resist pattern was deteriorated, the dimensional change of the resist pattern was narrowed by 8 nm.

Example 2 In Example 1, Polymer 1 was replaced with Polymer 2 of the same amount,
Further, a positive resist solution was prepared in the same manner as in Example 1 except that the silicon wafer provided with the organic antireflection film was changed to a silicon wafer, and then a resist pattern was formed under the same conditions as in Example 1. At that time, the sensitivity defined as in Example 1 was 18 mJ / cm ² . When the cross-sectional shape of the resist pattern at that time was observed with an SEM photograph, it was rectangular. In addition, a 0.15 μm line and space was resolved as the limit resolution. Further, the dry etching resistance defined as in Example 1 was 1.2. Further, when the electron beam resistance having the same definition as in Example 1 was examined, the dimensional change in the resist pattern was smaller by 11 nm from the initial resist pattern size.

Comparative Example 1 A positive resist solution was prepared in the same manner as in Example 1 except that Polymer 1 was replaced with the same amount of Polymer 3, and then the same conditions as in Example 1 were used. To form a resist pattern. In this case, the sensitivity having the same definition as in Example 1 is 2
It was 4 mJ / cm ² . When the cross-sectional shape of the resist pattern at that time was observed with an SEM photograph, it was slightly tapered. The limit resolution is 0.16
The resolution was only up to the μm line and space. The dry etching resistance defined in the same manner as in Example 1 was 1.3. When the electron beam resistance having the same definition as in Example 1 was examined, the dimensional change of the resist pattern was narrowed by 8 nm from the initial resist pattern size.

Comparative Example 2 A positive resist solution was prepared in the same manner as in Example 2 except that Polymer 2 was replaced with the same amount of Polymer 4, and then the same conditions as in Example 2 were used. To form a resist pattern. In this case, the sensitivity defined as in Example 2 is 3
It was 0 mJ / cm ² . When the cross-sectional shape of the resist pattern at that time was observed with an SEM photograph, it was slightly tapered. The limit resolution is 0.16
The resolution was only up to the μm line and space. Further, the dry etching resistance defined as in Example 1 was 1.2. Further, when the electron beam resistance having the same definition as in Example 1 was examined, the dimensional change in the resist pattern was 10 nm narrower than the initial resist pattern size.

Example 3 100 parts by weight of a copolymer having the following structural formula

[0085]

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(Wherein x ′, y ′ and z ′ are each 50
Mol%, 40 mol% and 10 mol%), 2 parts by weight of triphenylsulfonium trifluoromethanesulfonate, 10 parts by weight of tert-butyl ester of cholic acid, 0.05 part by weight of malonic acid, 0.1 part by weight of tripentylamine.
05 parts by weight were dissolved in 570 parts by weight of propylene glycol monomethyl ether acetate to obtain a positive resist solution. Next, this resist solution is applied on a silicon wafer provided with an organic antireflection film DUV-30 (manufactured by Brewer Science) at a film thickness of 1000 ° using a spinner, and dried on a hot plate at 150 ° C. for 90 seconds. Thus, a resist layer having a thickness of 0.5 μm was formed. Next, after selectively irradiating an ArF excimer laser (193 nm) with an ArF exposure apparatus (manufactured by Nikon Corporation), PEB treatment was performed at 140 ° C. for 90 seconds, and then a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 30 seconds. It was developed with a paddle, washed with water for 30 seconds and dried. Such 0.25μm of a line-and-space pattern formed by the operation 1: mJ / cm ² as sensitivity exposure time that is formed in one (energy) was measured in units, it was 30 mJ / cm ^2. When the cross-sectional shape of the resist pattern at that time was observed with an SEM photograph, it was rectangular. The limit resolution is 0.15
A μm line and space was resolved. Also,
When the novolak was set to 1, the amount of film reduction per unit time was determined as the dry etching resistance.
Met. In addition, as electron beam resistance, a high-resolution FEB length measuring apparatus “S-8820” manufactured by Hitachi, Ltd. was processed for 60 seconds to check whether the resist pattern was deteriorated. There was no change from.

Example 4 A positive resist solution was prepared in the same manner as in Example 3 except that the polymer was replaced with the same amount of the polymer represented by the following structural formula. A resist pattern was formed under the same conditions as in Example 3.

[0088]

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(Where g, h, i and j are each 1
(5 mol%, 25 mol%, 10 mol%, and 50 mol%) The exposure time at which a 0.18 μm line and space is formed at a ratio of 1: 1 was measured in mJ / cm ² (energy amount) as sensitivity. However, it was 45 mJ / cm ² . When the cross-sectional shape of the resist pattern at that time was observed with an SEM photograph, it was rectangular. Further, the line and space with a limit resolution of 0.17 μm was resolved. The dry etching resistance defined as in Example 3 was 1.2. Further, when the electron beam resistance having the same definition as in Example 3 was examined, the dimensional change in the resist pattern was 10 nm narrower than the initial resist pattern size.

Comparative Example 3 A positive resist solution was prepared in the same manner as in Example 3 except that the polymer was replaced with the same amount of the polymer represented by the following structural formula. A resist pattern was formed under the same conditions as in Example 3.

[0091]

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(Where x ″, y ″ and z ″ are 50
Mol%, 30 mol% and 20 mol%, and Ad is 2 mol%.
-Represents a methyl adamantyl group. In addition, a line and space with a limiting resolution of 0.16 µm was resolved. The dry etching resistance defined in the same manner as in Example 3 was 1.5. Example 3
When the electron beam resistance was defined in the same manner as described above, the dimensional change in the resist pattern was found to be 40 nm narrower than the initial resist pattern size.

[0093]

According to the present invention, the sensitivity is excellent, the resolution and the sectional shape of the resist pattern are excellent and the cost is low.
A positive resist composition for ArF capable of forming a resist pattern having a small dimensional change in the resist pattern size and excellent in electron beam resistance even under the influence of an electron beam, and an acid-dissociable group-containing monomer used therefor are provided.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 45/00 C08L 45/00 H01L 21/027 H01L 21/30 502R (72) Inventor Satoshi Fujimura Kawasaki, Kanagawa Prefecture 150 Nakamurako, Nakahara-ku, Tokyo Tokyo Chemical Industry Co., Ltd. (72) Inventor Miwa Katashima 150 Nakamaruko Nakahara-ku, Kawasaki City, Kanagawa Prefecture Tokyo Chemical Industry Co., Ltd.

Claims (17)

[Claims] 1. A positive resist composition comprising (A) a polymer containing at least a unit represented by the following general formula (I) and (B) a compound capable of generating an acid upon irradiation with radiation. Embedded image (Wherein R represents a hydrogen atom or a lower alkyl group, R ¹
Represents an alkyl group having 2 or more carbon atoms, and n is 0 or 1.) 2. The positive resist composition according to claim 1, wherein the component (A) is a copolymer of the unit represented by the general formula (I) and another copolymerizable monomer. 3. The positive resist composition according to claim 2, wherein the other copolymerizable monomer is at least one selected from maleic anhydride and a polycyclic olefin. 4. The positive resist composition according to claim 3, wherein said another copolymerizable monomer is maleic anhydride. 5. The positive resist according to claim 3, wherein the unit of the other copolymerizable monomer is at least one unit derived from a polycyclic olefin represented by the following general formula (II). Composition. Embedded image Wherein R and n are the same as described above, and R ² is a hydrogen atom, a carboxyl group or an alkyloxycarbonyl group having 1 to 10 carbon atoms and having at least one hydroxyl group. 6. The positive resist composition according to claim 4, wherein the component (A) is a polymer containing at least a unit represented by the following general formula (III). Embedded image Wherein R, R ¹ and n are as defined above. 7. The composition according to claim 1, wherein the component (A) comprises at least the compound represented by the general formula (II)
7. The positive resist composition according to claim 6, which is a polymer containing a unit represented by I) and the following general formula (IV). Embedded image (Wherein R is the same as described above, R ³ is an alkyl group having 1 to 10 carbon atoms having a hydroxyl group, and m is 0 or 1) 8. The positive resist composition according to claim 5, wherein the component (A) is a polymer represented by the general formula (V) containing at least the following three units. Embedded image (Wherein R, R ¹ and n are the same as above. R ⁴ is a group having 1 to 10 carbon atoms having at least one hydroxyl group)
Is an alkyloxycarbonyl group of 9. The positive resist composition according to claim 1, wherein R ¹ is a lower alkyl group having 2 or more carbon atoms. 10. The method according to claim 7, wherein R ³ is a lower monohydroxyalkyl group or a lower dihydroxyalkyl group.
Or the positive resist composition according to 9. 11. The positive resist composition according to claim 9, wherein R ¹ is an ethyl group. 12. The positive resist composition according to claim 10, wherein R ³ is a 2-hydroxypropyl group. 13. The positive resist composition according to claim 1, further comprising 0.01 to 5% by weight of an organic carboxylic acid or an oxo acid of phosphorus or a derivative thereof based on (A). object. 14. An organic amine is added to (A) in an amount of 0.1 to 0.1%.
14. The positive resist composition according to claim 1, wherein the composition is contained in an amount of from 0.01 to 5% by weight. 15. The composition according to claim 1, further comprising a bile acid and an ester of an acid dissociable group in an amount of 1 to 100% by weight based on (A).
15. The positive resist composition according to any one of items 1 to 14. 16. The bile acid ester is a tertiary salt of cholic acid, deoxycholic acid, ursocholic acid and lithocholic acid.
The positive resist composition according to claim 15, which is t-butyl ester. 17. An acid-labile group-containing monomer represented by the following general formula (VI). Embedded image (Wherein R represents a hydrogen atom or a lower alkyl group, R ¹
Represents an alkyl group having 2 or more carbon atoms)