KR100420020B1 - Positive-type resist composition, and acid dissociative group-containing monomer for use in the same - Google Patents

Abstract

The present invention relates to a composition comprising (A) a polymer of the following units and (B) an acid generator:

According to the present invention, there is provided a positive resist composition for ArF and an acid dissociable group-containing monomer which inexpensively forms a pattern excellent in sensitivity, resolution, electron beam resistance and cross-sectional shape.

Description

POSITIVE-TYPE RESIST COMPOSITION, AND ACID DISSOCIATIVE GROUP-CONTAINING MONOMER FOR USE IN THE SAME}

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

At present, chemically amplified resists for KrF (248 nm) excimer lasers have already been put into practical use for resist pattern formation of 0.30 mu m or less.

On the other hand, the development of a lithography process using an ArF (193 nm) excimer laser of 0.15 mu m or less has been actively carried out, and many proposals have been made for resists for ArF.

For example, Japanese Patent Application Laid-Open Nos. 9-230595 and 9-244247 disclose resists using polycyclic polyolefin resins having acid dissociable groups such as tert-butyloxycarbonyl group or 1-methylcyclohexyloxycarbonyl group. Is being proposed.

Further, WO97 / 33198, JP-A-10-10739 and JP-A-10-111569 have a nort having acid dissociable groups such as tert-butyloxycarbonyl group and 1-methyl-1-cyclohexyloxycarbonyl group. Resists using a resin obtained by copolymerizing bornene and maleic anhydride have been proposed.

However, since the acid dissociable groups proposed in these publications are insufficient in dissociation by an acid generated in an acid generator, there is a problem that the sensitivity using a resin having such an acid dissociable group is insufficient. . In addition, resolution and resist pattern cross-sectional shapes are not enough, and improvement is desired.

Moreover, the 1-methyl-1-cyclohexyloxycarbonyl group has a problem that it is industrially difficult because 1-methyl-1-hydroxycyclohexane which is a raw material for synthesizing this is very expensive.

Further, Japanese Unexamined Patent Publication Nos. Hei 10-130340, Hei 10-153864, Hei 10-198035, Hei 10-207058, Hei 10-207070, Hei 10-218941 Japanese Patent Application Laid-Open Publication No. Hei 10-218947 and others also propose a positive resist for ArF, but it is not proposed to be particularly characterized as an acid dissociable group.

On the other hand, Japanese Laid-Open Patent Publication No. Hei 10-161313 discloses that high sensitivity is achieved by bonding a lower alkyl group having 2 or more carbon atoms such as an ethyl group and a propyl group to a carbon atom at one position of an alicyclic hydrocarbon group. In addition, Paragraph No. 0029 of this publication discloses that an alicyclic hydrocarbon group is particularly preferably a condensed ring such as adamantane because the dry etching resistance is insufficient in a monocyclic group such as a cyclohexyl group.

However, adamantane is very expensive and difficult to industrialize. In addition, in the semiconductor industry in recent years, the provision of inexpensive materials has increased more than ever before and has become industrially important. In addition, although the above-mentioned publication discloses the polymer which has an alicyclic hydrocarbon group in the side chain of an acrylic resin specifically, the acrylic resin which has an alicyclic hydrocarbon group in such side chain has a problem that electron beam tolerance is small.

With electron beam resistance, for example, in the manufacture of semiconductor devices, the profile shape of the resist pattern is determined by SEM (scanning electron microscope), and the resist pattern dimension is a high resolution FEB measuring device (e.g., manufactured by Hitachi Seisakusho). S-8820 "), there is a problem that the resist pattern is deteriorated under the influence of the electron beam used in such a device, causing a dimensional change in the resist pattern size.

Accordingly, the present invention provides a positive resist composition for ArF that is excellent in sensitivity, resolution, and resist pattern cross-sectional shape and is inexpensive, so that a resist pattern excellent in electron beam resistance with little dimensional change in resist pattern size can be formed even under the influence of an electron beam. And an acid dissociable group-containing monomer for use therein.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining, the objective of this invention is to use the base resin synthesize | combined using the novel polycyclic olefin monomer which has a 1-alkyl (C2 or more) -1-cyclohexyloxycarbonyl group as an acid dissociable group. Was achieved.

The invention of claim 1 is a positive resist composition comprising (A) a polymer containing at least the unit represented by the following formula (1) and (B) a compound which generates an acid by irradiation with radiation:

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

The invention of claim 2 is the positive resist composition according to claim 1, wherein the component (A) is a copolymer of the unit represented by the formula (1) with another copolymerizable monomer.

The invention of claim 3 is the positive resist composition according to claim 2, wherein the other copolymerizable monomer is at least one member selected from maleic anhydride and polycyclic olefins.

The invention of claim 4 is the positive resist composition according to claim 3, wherein the other copolymerizable monomer is maleic anhydride.

The invention of claim 5 is the positive resist composition according to claim 3, wherein the unit of the other copolymerizable monomer is at least one of units derived from a polycyclic olefin represented by the following formula (2):

(Wherein R and n are the same as described above and R ² is a C1-C10 alkyloxycarbonyl group having a hydrogen atom, a carboxyl group or at least one hydroxyl group)

The invention of claim 6 is the positive resist composition according to claim 4, wherein the component (A) contains at least a unit represented by the following general formula (3):

(Wherein R, R ¹ and n are the same as above)

The invention of claim 7 is the positive resist composition according to claim 6, wherein the component (A) is a polymer comprising at least the units represented by the general formula (3) and the following general formula (4):

(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 invention of claim 8 is the positive resist composition according to claim 5, wherein the component (A) is a polymer represented by the formula (5) comprising three or more units:

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

The invention of claim 9 is the positive resist composition according to any one of claims 1, 2, 3, 4, 5, 6 or 8, wherein R ¹ is a lower alkyl group having 2 or more carbon atoms.

The invention of claim 10 is the positive resist composition according to claim 7 or 9, wherein R ³ is a lower monohydroxyalkyl group or a lower dihydroxyalkyl group.

The invention of claim 11 is the positive resist composition according to claim 9, wherein R ¹ is an ethyl group.

The invention of claim 12 is the positive resist composition according to claim 10, wherein R ³ is a 2-hydroxypropyl group.

The positive resist composition according to any one of claims 1 to 12, further comprising 0.01 to 5 wt% of an organic carboxylic acid or an oxo acid or a derivative thereof of phosphorus based on (A). to be.

Invention of Claim 14 is the positive resist composition in any one of Claims 1-13 which mix | blends 0.01-5 weight% of organic amines with respect to (A) further.

Invention of Claim 15 is the positive resist composition in any one of Claims 1-14 which mix | blends 5-20 weight% of esters of a bile acid and an acid dissociable group with respect to (A).

The invention of claim 16 is the positive resist composition according to claim 15, wherein the bile acid ester is tert-butyl ester of cholic acid, deoxycholic acid, ulsocholic acid and lithopholic acid.

The invention of claim 17 is an acid dissociable group-containing monomer represented by the following general formula (6):

Wherein R and R ¹ are the same as defined above.

Embodiment of the invention

(A) component

Component (A) of the present invention is a polymer containing at least the unit represented by the following general formula (1):

[Formula 1]

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

The unit represented by the formula (1) is a unit derived from a polycyclic olefin such as bicyclo [2.2.1] -2-heptene (norbornene), tetracyclo [4.4.0.1 ^2.5 .1 ^7.10 ] -3-dodecene It has a main chain in a polymer, and has the alkyl-1-cyclohexyl (acid dissociable group part of this invention) oxycarbonyl group of 1-C2 or more in the 5 or 8 position on the ring.

Component (A) of the present invention has a unit derived from such a polycyclic olefin as a main chain, and has an acid dissociable group-containing oxycarbonyl (ester) group of the present invention on the ring, so It is possible to form a resist pattern excellent in dry etching resistance without using an expensive polycyclic hydrocarbon group such as a methyl group. In addition, the electron beam resistance is also excellent.

In addition, since the acid dissociable group portion of the present invention can be used at the same time, it is possible to provide an inexpensive positive resist composition.

Further, since the acid dissociable group portion of the present invention is excellent in acid dissociation property, sensitivity, resolution and resist pattern cross-sectional shape are improved.

In the unit represented by General formula (1), R is a hydrogen atom or lower alkyl group, such as a methyl group, an ethyl group, and a propyl group. Monomers that form the units of formula (1) are synthesized by (meth) acrylic acid-alkyl-1-cyclohexyl ester having 2 or more carbon atoms and cyclopentadiene or dicyclopentadiene by a known Diels-Alder reaction. can do. In such a reaction, since a monomer forming a unit of the formula (1) can be obtained, R is preferably a hydrogen atom or a methyl group.

If R <^1> is a C2 or more alkyl group, it will not specifically limit, but lower alkyl groups, such as an ethyl group, a propyl group, and a butyl group, are preferable. By using such a lower alkyl group for R ¹ , since acid dissociation is improved, sensitivity, resolution and resist pattern cross-sectional shape are improved.

The component (A) may be a polymer containing at least 1 to 80 mol%, preferably 15 to 50 mol% of a unit represented by the formula (1), and a copolymer with another copolymerizable monomer is preferable.

As a unit of another copolymerizable monomer, the compound which has a well-known ethylenic double bond can be used arbitrarily according to the objective.

Especially as a compound which has such ethylenic double bond, since at least 1 sort (s) chosen from maleic anhydride and polycyclic olefin is excellent in resolution and resist pattern cross-sectional shape, it is preferable.

Examples of the polycyclic olefins include polycyclic olefins such as bicyclo [2.2.1] -2-heptene (norbornene) and tetracyclo [4.4.0.1 ^2.5 .1 ^7.10 ] -3-dodecene. Moreover, you may have various substituents, such as a functional group which improves alkali solubility on the ring, and a functional group which improves the adhesiveness of a board | substrate and a 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 (2):

[Formula 2]

(Wherein R and n are the same as described above and R ² is a C1-C10 alkyloxycarbonyl group having a hydrogen atom, a carboxyl group or at least one hydroxyl group)

When R <^2> is a hydrogen atom, dry etching resistance is improved by an unsubstituted polycyclic olefin unit. When R <^2> is a carboxyl group, alkali solubility is improved. In the case of a C1-C10 alkyloxycarbonyl group having at least one hydroxyl group, the adhesion between the silicon wafer or the silicon wafer on which the inorganic film is formed and the resist layer is improved. The alkyloxycarbonyl group having at least one hydroxyl group is preferably an alkyloxycarbonyl group having 1 to 2 carbon atoms or 2 to 10 carbon atoms.

Specifically, a hydroxymethyloxycarbonyl group, hydroxyethyloxycarbonyl group, hydroxypropyloxycarbonyl group, hydroxybutyloxycarbonyl group, 2,3-dihydroxybutyloxycarbonyl group, hydroxypentyloxycarbonyl group, etc. are mentioned, Especially 2-hydroxypropyloxycarbonyl group is preferable.

In the case of the copolymers of the formulas (1) and (2), the units of the formula (1) are 1 to 80 mol%, preferably 10 to 50 mol%, and the units of the formula (2) are 20 to 99 mol%, preferably 50 to 90 mol% It is preferable because a range improves adhesiveness and resolution.

The unit represented by the formula (2) is capable of copolymerizing one or two or more kinds at the same time, and is particularly excellent in all of the dry etching resistance, alkali solubility and adhesion, and therefore, the unit represented by the formula (5) including at least three units Polymers are preferred:

[Formula 5]

(Wherein R, R ¹ and n are the same as described above, and R ⁴ is a C1-C10 alkyloxycarbonyl group having at least one hydroxyl group)

In the case of the copolymer of the formula (5), x is 1 to 80 mol%, preferably 10 to 50 mol%, y is 1 to 45 mol%, preferably 1 to 40 mol%, z is 1 to 20 mol%, Preferably, the range of 5-10 mol% is preferable considering alkali solubility, adhesiveness, and resolution.

The monomer of the unit represented by the formula (2) is a hydroxyalkyl ester and cyclopentadiene of (meth) acrylic acid or (meth) acrylic acid, similarly to the monomer of the unit represented by the formula (1), except that R ² is a hydrogen atom. Or dicyclopentadiene can be synthesize | combined by the Diels-Alder reaction which is a well-known reaction. When R <^2> is a hydrogen atom, you may use polycyclic olefin which does not have substituents, such as norbornene.

When the other copolymerizable monomer is maleic anhydride, a polymer containing at least the unit represented by the following general formula (3) is preferable:

[Formula 3]

(Wherein R, R ¹ and n are the same as above)

In addition, the use of a polymer containing at least the units represented by the above formula (3) and the following formula (4) improves the adhesion to the substrate is preferable:

[Formula 4]

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

The unit represented by the formula (3) dissolves the polycyclic olefin monomer and the maleic anhydride represented by the formula (6) in a suitable organic solvent such as dioxane and tetrahydrofuran to form benzoyl peroxide, 2,2'-azisobutyronitrile. It can be obtained by adding and copolymerizing radical polymerization initiators, such as acetyl peroxide and lauryl peroxide.

When n = 0, the polycyclic olefin monomer represented by the formula (6) is a compound of 1-alkyl (carbon number 2 or more) -1-hydroxycyclohexane (hereinafter simply referred to as cyclohexane derivative) and (meth) acrylic acid halide. After synthesize | combining ester, this and cyclopentadiene can be synthesize | combined easily by the Diels-Alder reaction.

The chemical reaction scheme is shown below:

Since a cyclohexane derivative is not commercially available, it can synthesize | combine by the nucleophilic addition reaction using cyclohexanone, the Grignard reagent, and alkyl lithium which are well-known reactions for obtaining alcohol from a ketone. This scheme is shown below:

(Wherein R ⁵ is an alkyl group having 2 or more carbon atoms)

In addition, the cyclohexane derivative is the first step of obtaining 1-alkynyl-1-hydroxycyclohexanol by nucleophilic addition reaction using cyclohexanone and metal alkynyl such as lithium acetylide or sodium acetylide, followed by hydrogen. The addition can be carried out through a second step. At this time, since 1-alkynyl-1-hydroxycyclohexanol can obtain a commercial item easily and at low cost, it can synthesize | combine only by a 2nd process.

The synthesis method according to the above two steps using the metal alkynyl, which is the latter synthesis method, is preferable because the number of reaction steps increases, but there is no by-product and can be obtained in high yield.

In particular, the method of hydrogenating 1-alkynyl-1-hydroxycyclohexanol is easy to obtain 1-alkyl-1-hydroxycyclohexanol at low cost, and since it is high in industrial value, it is preferable. This synthesis procedure is shown below:

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

In the case of n = 2, the polycyclic olefin monomer represented by the formula (6) is a dicyclo which is a dimer of cyclopentadiene in the esterified product of a cyclohexanone derivative with acrylic acid or methacrylic acid as in the case of n = 1. It can be synthesized by pentadiene and Diels-Alder reaction.

In the unit represented by the formula (4), R is the same as in the formula (1).

R ³ is a functional group for improving the adhesion between the silicon wafer and the silicon wafer on which the inorganic film is formed 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 hydroxyl groups are used. An alkyl group having 1 to 10 carbon atoms is preferable.

Specifically, hydroxymethyl group, hydroxyethyl group, hydroxypropyl group, hydroxybutyl group, dihydroxybutyl group, hydroxypentyl group and the like are particularly 2-hydroxypropyl, 2,3-dihydroxybutyl Group is preferred.

The monomer of the unit represented by General formula (4) can be obtained by carrying out the Diels-Alder reaction of the hydroxyalkyl ester of (meth) acrylic acid, cyclopentadiene, or dicyclopentadiene similarly to the unit represented by General formula (2).

The copolymerization ratio of maleic anhydride and a polycyclic olefin monomer in the formula (3) or (4) is, in theory, 50 mol% each. However, since copolymerization of maleic anhydride and polycyclic olefin monomers also occurs in practice, it is 40 to 60 mol% of units derived from maleic anhydride and 40 to 60 mol% of units derived from polycyclic olefin monomers.

In the case of the copolymers of the formulas (3) and (4), 40 to 90 mol% of the units of the formula (3), preferably 50 to 80 mol%, 10 to 60 mol% of the units of the formula (4), preferably 20 to 50 mol% to be. When the unit of the formula (3) is smaller than these ranges, the sensitivity is lowered, and when too large, the adhesion with the substrate is inferior.

In addition to the units represented by the formulas (2), (3) and (4), known monomers may be copolymerized as necessary as monomers of the base resin of the conventional ArF positive type resist.

The weight average molecular weight of (A) component of this invention is 2,000-15,000, Preferably the range of 3,000-6,000 is good.

(B) component

In this invention, a well-known thing can be used as an acid generator of a chemically amplified resist as (B) component, It does not specifically limit. Preferably, the anion is an onium salt of fluoroalkylsulfonic acid ions having 1 to 10 carbon atoms.

Examples of the cation of the onium salt include phenyl iodonium or sulfonium which may be substituted with a lower alkyl group such as methyl group, ethyl group, propyl, n-butyl group, tert-butyl or lower alkoxy group such as methoxy group or ethoxy group.

As an anion, some or all of the hydrogen atoms of a C1-C10 alkyl group are fluorinated fluoroalkyl sulfonic acid ions. The longer the carbon number and the lower the fluorination rate (the ratio of the fluorine atoms in the alkyl group), the lower the strength as the sulfonic acid. Therefore, fluoroalkylsulfonic acid in which all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are fluorinated is preferable. .

Specifically, trifluoromethanesulfonate or nonafluorobutanesulfonate of diphenyl iodonium, trifluoromethanesulfonate or nonafluorobutanesulfonate of bis (4-tert-butylphenyl) iodonium, and tri Trifluoromethanesulfonate or nonafluorobutanesulfonate of phenylsulfonium, trifluoromethanesulfonate or nonafluorobutanesulfonate of tri (4-methylphenyl) sulfonium, and the like. Of these, methanesulfonate or nonafluorobutanesulfonate of bis (4-tert-butylphenyl) iodonium is preferable.

These may use 1 type (s) or 2 or more types simultaneously.

The component (B) may be used in an amount of 0.1 to 20% by weight, preferably 1 to 10% by weight, based on the component (A).

Various additives other than the above can be mix | blended with the composition of this invention as needed. Examples of the additive 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 organic carboxylic acids such as saturated or unsaturated aliphatic carboxylic acid, alicyclic carboxylic acid, and aromatic carboxylic acid, but are not particularly limited. 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. As unsaturated aliphatic carboxylic acid, acrylic acid, crotonic acid, isocrotonic acid, 3-butene acid, methacrylic acid, 4-pentene acid, propiolic acid, 2-butynic acid, maleic acid, fumaric acid, acetylene carboxylic acid, etc. Can be mentioned. As alicyclic carboxylic acid, 1,1-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid Acids, 1,1-cyclohexanediacetic acid, and the like. As aromatic carboxylic acid, aromatic which has substituents, such as hydroxyl group, nitro group, carboxyl group, such as p-hydroxybenzoic acid, o-hydroxybenzoic acid, 2-hydroxy-3-nitrobenzoic acid, phthalic acid, terephthalic acid, isophthalic acid, etc. Carboxylic acid can be mentioned.

Specific examples of phosphorus oxo acids or derivatives thereof include phosphoric acid or phosphorous acid such as phosphoric acid, phosphorous acid, phosphoric acid di-butyl ester, phosphoric acid diphenyl ester, or derivatives such as phosphorous acid or esters thereof, phosphonic acid, phosphonic acid dimethyl ester, and phosphonic acid di. derivatives such as phosphonic acids and esters thereof, such as n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester and phosphonic acid dibenzyl ester, phosphinic acids such as phosphinic acid and phenylphosphinic acid and derivatives thereof Although it may be mentioned, it is not limited to this.

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

Examples of the organic amine include aliphatic amines, aromatic amines, and heterocyclic amines, but are not limited thereto. Examples of the aliphatic amines include diethylamine, triethylamine, n-propylamine, di-n-propylamine, tri-n-propylamine, triisopropanolamine, isopropylamine, tributylamine, tripentylamine and triethanolamine , Dipropanolamine, tripropanolamine and the like. As aromatic amines, benzylamine, aniline, N-methylaniline, N, N-dimethylaniline, o-methylaniline, m-methylaniline, p-methylaniline, N, N-diethylaniline, diphenylamine, di -p-tolylamine, etc. are mentioned. Examples of the heterocyclic amine include pyridine, o-methylpyridine, o-ethylpyridine, 2,3-dimethylpyridine, 4-ethyl-2-methylpyridine, and 3-ethyl-4-methylpyridine.

Among these, aliphatic amines such as tripentylamine are preferable because of their high transmittance to ArF laser light and excellent resist pattern shapes.

The compounding ratio of the organic carboxylic acid or the oxo acid of phosphorus or its derivative (s) is 0.01-5 weight% with respect to (A) component, Preferably it is the range of 0.02-0.2 weight%. If it is this range, resolution and sensitivity will improve and it is preferable.

The compounding ratio of organic amine is 0.01-5 weight% with respect to (A) component, Preferably it is the range of 0.02-0.2 weight%. If it is this range, a resist pattern shape and a sensitivity will improve and it is preferable.

Esters of bile acids and acid dissociable groups are known as dissolution inhibitors of positive resists for ArF and are not particularly limited. The esters include, but are not limited to, tert-butyl ester, tetrahydropyranyl ester, ethoxyethyl ester, and the like of bile acids selected from cholic acid, deoxycholic acid, ulsocholic acid and lithopholic acid. The ester exhibits high permeability to the ArF excimer laser and is used as necessary to improve the contrast of the resist pattern because the acid dissociable group is dissociated by the action of the acid generated from the acid generator. The compounding ratio is 5-20 weight% with respect to (A) component.

In addition, the composition of the present invention may further contain a compatible additive, for example, an antihalation agent, as appropriate.

It is preferable that the positive photoresist composition of this invention melt | dissolves said each component in a suitable solvent, and uses it in the form of a solution. As an example of such a solvent, the solvent used for the conventional positive photoresist composition is mentioned, For example, Ketones, such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, 2-heptanone; Ethylene glycol, propylene glycol, diethylene glycol, ethylene glycol monoacetate, propylene glycol monoacetate, diethylene glycol monoacetate, or monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether thereof Polyhydric alcohols and derivatives thereof; Cyclic ethers such as dioxane; And esters such as ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate and ethyl ethoxypropionate. These may be used independently and may mix and use 2 or more types.

An example of a suitable method of using the composition of the present invention is shown firstly, a solution of a positive resist composition is first applied onto a substrate such as a silicon wafer with a spinner, dried to form a photosensitive layer, and then a pattern is drawn. It exposes through a photomask. Next, after exposing this to post-exposure heating (PEB) and developing with a developing solution, for example, an alkaline aqueous solution such as 1 to 10% by weight of tetramethylammonium hydroxide (TMAH) aqueous solution, the exposed portion is dissolved and removed to adhere to the mask pattern. An image (resist pattern) can be obtained. In order to further increase 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.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Preparation Example 1 (Synthesis of Polycyclic Olefin Monomer)

128 g of 1-ethyl-1-hydroxycyclohexane and 120 g of triethylamine were dissolved in 600 ml of tetrahydrofuran, stirred while cooling in an ice bath, and 91 g of acrylate chloride was added dropwise thereto over 10 minutes. Then, it returned to room temperature slowly and stirred for 24 hours again. After the reaction solution was sufficiently washed with water until neutral, tetrahydrofuran was removed with a rotary evaporator to obtain 95 g (yield 52%) of 1-ethyl-1-cyclohexyl acrylate.

Subsequently, 91 g of obtained 1-ethyl-1-cyclohexyl acrylate was stirred while cooling in an ice bath, and 35 g of cyclopentadiene obtained by heating and decomposing dicyclopentadiene to 40 ° C. was added dropwise over 60 minutes. . After completion of the dropwise addition, the mixture was stirred for 12 hours. The reaction solution was distilled under reduced pressure under conditions of 1 mmHg and 115 to 117 ° C to obtain a compound having the following formula:

In addition, Et represents an ethyl group. The yield was 119 g (96% yield).

In addition, proton NMR analytical data is:

0.8 ppm, 1.2-1.7 ppm, 1.9 ppm, 2.2 ppm, 2.9 ppm, 3.2 ppm, 6.0 ppm, 6.2 ppm;

FTIR analysis data is:

2972 cm ^-1 , 2936 cm ^-1 , 2863 cm ^-1 , 2726 cm ^-1 , 1449 cm ^-1 , 1336 cm ^-1 , 1271 cm ^-1 ,

The compound was identified from the above analytical data.

Preparation 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, 4.3 g of azobisisobutyronitrile was added as a reaction initiator, and the polymerization reaction was carried out at 70 ° C for 10 hours. After the reaction was completed, the operation of pouring the reaction into 1 liter of n-heptane to precipitate the polymer was repeated twice. The obtained copolymer was dried under reduced pressure at room temperature.

In this manner, a copolymer represented by the following formula was obtained. The yield of this copolymer was 26 g, the weight average molecular weight was 4300 and the degree of dispersion was 1.4:

Preparation Example 3 (Synthesis of Polymer 2)

24.8 g of the polycyclic olefin monomer obtained in Production Example 1 and 2-hydroxypropyl acrylate were reacted with cyclopentadiene and DIEL-Alder to dissolve 4.9 g of the polycyclic olefin monomer and 12.25 g of maleic anhydride in 42 g of dioxane, As a reaction initiator, 4.2 g of azobisisobutyronitrile was added and the polymerization reaction was carried out at 70 ° C for 10 hours. After the reaction was completed, the operation of pouring the reaction into 1 liter of n-heptane to precipitate the polymer was repeated twice. The obtained copolymer was dried under reduced pressure at room temperature.

In this manner, a copolymer represented by the following formula was obtained. The yield of this copolymer was 26 g, the weight average molecular weight was 4700 and the degree of dispersion was 1.4:

In addition, x and y were 80 mol% and 20 mol%, respectively.

Comparative Preparation Example 1 (Synthesis of Polymer 3)

29.25 g of polycyclic olefin monomers and 12.25 g of maleic anhydride obtained by reacting 1-methyl-1-cyclohexyl acrylic acid with cyclopentadiene and Diels-Alder are dissolved in 42 g of dioxane and used as azobisisobutyro as a reaction initiator. 4.2 g of nitriles were added, and the polymerization reaction was carried out at 70 ° C for 10 hours. After the reaction was completed, the operation of pouring the reaction into 1 liter of n-heptane to precipitate the polymer was repeated twice. The obtained copolymer was dried under reduced pressure at room temperature.

In this manner, a copolymer represented by the following formula was obtained. The yield of this copolymer was 24 g with a weight average molecular weight of 4800 and a degree of dispersion of 1.6:

Comparative Preparation Example 2 (Synthesis of Polymer 4)

Polycyclic olefin monomer obtained by reacting 1-methyl-1-cyclohexyl acrylic acid with cyclopentadiene and diels-alder, and 23.4 g of polycyclic olefin monomers and 2-hydroxypropyl acrylate by cyclopentadiene 4.9 g and 12.25 g of maleic anhydride were dissolved in 41 g of dioxane, 4.1 g of azobisisobutyronitrile was added as a reaction initiator, and the polymerization reaction was carried out at 70 ° C for 10 hours. After the reaction was completed, the operation of pouring the reaction into 1 liter of n-heptane to precipitate the polymer was repeated twice. The obtained copolymer was dried under reduced pressure at room temperature.

In this manner, a copolymer represented by the following formula was obtained. The yield of this copolymer was 24 g with a weight average molecular weight of 5100 and a degree of dispersion of 1.6:

In addition, x 'and y' were 80 mol% and 20 mol%, respectively.

Example 1

100 parts by weight of the polymer 1 obtained in Preparation Example 2, 2 parts by weight of triphenylsulfonium trifluoromethanesulfonate, 10 parts by weight of tert-butyl ester of malic acid, 0.05 parts by weight of malonic acid and 0.1 parts by weight of tripentylamine, and propylene glycol mono It melt | dissolved in 570 weight part of methyl ether acetate, and obtained the positive resist solution.

Subsequently, this resist solution was applied onto a silicon wafer on which an organic antireflective film ("DUV-30" trade name, manufactured by Brewer Science Co., Ltd.) was formed at a film thickness of 1000 mm 3 using a spinner, and the film was heated at 150 ° C. for 90 seconds on a hot plate. By drying, a resist layer having a thickness of 0.5 mu m was formed. Subsequently, an ArF excimer laser (193 nm) was selectively irradiated with an ArF exposure apparatus (manufactured by Nikon Corporation), followed by PEB treatment at 140 ° C. for 90 seconds, followed by a paddle for 30 seconds with a 2.38% by weight aqueous tetramethylammonium hydroxide solution. It developed, washed with water for 30 seconds, and dried.

It was 16 mJ / cm <2> when the exposure time in which the 0.18 micrometer line-and-space formed by such an operation was formed by 1: 1 was measured in mJ / cm <2> (energy amount) unit as a sensitivity.

The resist pattern cross-sectional shape at this time was observed in a SEM photograph, and was rectangular.

As the limit resolution, 0.15 탆 line and space was resolved.

In addition, as the dry etching resistance, the film reduction amount per unit time when the novolak was 1 was found to be 1.2 (in addition, the smaller the numerical value, the higher the dry etching resistance).

Moreover, as electron beam tolerance, when it processed for 60 second with the high resolution FEB measuring apparatus ("S-8820" by Hitachi Seisakusho), and investigated whether the resist pattern did not deteriorate, the dimensional change in the resist pattern was narrowed by 8 nm.

Example 2

In Example 1, the positive resist solution was manufactured by the same method as Example 1 except having changed the polymer 1 into the polymer 2 of the same quantity, and also changing the silicon wafer which formed the organic antireflective film into the silicon wafer. Subsequently, a resist pattern was formed under the same conditions as in Example 1.

The sensitivity of the same definition as in Example 1 at that time was 18 mJ / cm 2.

It was rectangular when the cross-sectional shape of the resist pattern at that time was observed by the SEM photograph.

As the limit resolution, 0.15 탆 line and space was resolved.

In addition, the dry etching resistance of the definition similar to Example 1 was 1.2.

Moreover, when the electron beam tolerance of the same definition as Example 1 was investigated, the dimension change to the resist pattern was 11 nm narrowed from the original resist pattern size.

Comparative Example 1

In Example 1, except having changed the polymer 1 into the same amount of the polymer 3, the positive resist solution was produced by the same method as Example 1, and the resist pattern was formed on the conditions similar to Example 1 then.

The sensitivity of the same definition as in Example 1 at that time was 24 mJ / cm 2.

The resist pattern cross-sectional shape at that time was observed in a SEM photograph, and was slightly tapered.

In the limit resolution, only resolution up to 0.16 탆 line and space was achieved.

In addition, the dry etching resistance of the same definition as Example 1 was 1.3.

Moreover, when the electron beam tolerance of the same definition as Example 1 was investigated, the dimensional change in the resist pattern narrowed 8 nm from the original resist pattern size.

Comparative Example 2

In Example 2, except having changed the polymer 2 into the polymer 4 of the same quantity, the positive resist solution was produced by the same method as Example 2, and the resist pattern was formed on the conditions similar to Example 2 after that.

The sensitivity of the definition similar to Example 2 at that time was 30 mJ / cm <2>.

The resist pattern cross-sectional shape at that time was observed in a SEM photograph, and was slightly tapered.

In the limit resolution, only resolution up to 0.16 탆 line and space was achieved.

In addition, the dry etching resistance of the definition similar to Example 1 was 1.2.

Moreover, when the electron beam tolerance of the same definition as Example 1 was investigated, the dimensional change in the resist pattern narrowed by 10 nm from the original resist pattern size.

Example 3

100 parts by weight of a copolymer having the formula:

(Wherein x ', y' and z 'are 50 mol%, 40 mol% and 10 mol%, respectively), 2 parts by weight of triphenylsulfonium trifluoromethanesulfonate and 10 parts by weight of tert-butyl ester of malic acid , 0.05 parts by weight of malonic acid and 0.05 parts by weight of tripentylamine were dissolved in 570 parts by weight of propylene glycol monomethyl ether acetate to obtain a positive resist solution.

Subsequently, this resist solution was applied onto a silicon wafer on which an organic antireflective film ("DUV-30" trade name, manufactured by Brewer Science Co., Ltd.) was formed at a film thickness of 1000 mm 3 using a spinner, and the film was heated at 150 ° C. for 90 seconds on a hot plate. By drying, a resist layer having a thickness of 0.5 mu m was formed. Subsequently, an ArF excimer laser (193 nm) was selectively irradiated with an ArF exposure apparatus (manufactured by Nikon Corporation), followed by PEB treatment at 140 ° C. for 90 seconds, followed by a paddle for 30 seconds with a 2.38 wt% tetramethylammonium hydroxide aqueous solution. It developed, washed with water for 30 seconds, and dried.

It was 30 mJ / cm <2> when the exposure time in which the 0.25-micrometer line-and-space formed by such an operation was formed in 1: 1 was measured by mJ / cm <2> (amount of energy) as a sensitivity. The resist pattern cross-sectional shape at this time was observed in a SEM photograph, and was rectangular.

As the limit resolution, 0.15 탆 line and space was resolved.

Moreover, as dry etching resistance, when film | membrane shrinkage per unit time at the time of making novolak 1 was calculated | required, it was 1.1.

In addition, as the electron beam resistance, a high-resolution FEB measuring device ("S-8820" manufactured by Hitachi Seisakusho Co., Ltd.) was treated for 60 seconds to examine whether the resist pattern was deteriorated. Did not do it.

Example 4

In Example 3, a positive resist solution was prepared in the same manner as in Example 3 except that the polymer was changed to the polymer represented by the same chemical formula below, and then a resist pattern was formed under the same conditions as in Example 3. :

Wherein g, h, i and j are 15 mol%, 25 mol%, 10 mol% and 50 mol%, respectively)

It was 45 mJ / cm <2> when the exposure time in which the 0.18 micrometer line-and-space is formed in 1: 1 was measured in mJ / cm <2> (energy amount) unit as a sensitivity. The resist pattern cross-sectional shape at this time was observed in a SEM photograph, and was rectangular.

In the limit resolution, 0.17 µm line and space was resolved.

In addition, the dry etching resistance of the definition similar to Example 3 was 1.2.

Moreover, when the electron beam tolerance of the same definition as Example 3 was investigated, the dimensional change in the resist pattern narrowed by 10 nm from the original resist pattern size.

Comparative Example 3

In Example 3, a positive resist solution was prepared in the same manner as in Example 3 except that the polymer was changed to the polymer represented by the same chemical formula below, and then a resist pattern was formed under the same conditions as in Example 3. :

(Wherein x ", y", z "are 50 mol%, 30 mol% and 20 mol%, respectively, Ad represents 2-methyladamantyl group)

In the limit resolution, 0.16 탆 line and space was resolved.

In addition, the dry etching resistance of the definition similar to Example 3 was 1.5.

Moreover, when the electron beam tolerance of the same definition as Example 3 was investigated, the dimensional change in the resist pattern narrowed 40 nm from the original resist pattern size.

According to the present invention, an ArF capable of forming a resist pattern having excellent sensitivity, excellent resolution and resist pattern cross-sectional shape, low cost, and excellent electron beam resistance with little dimensional change in resist pattern size even under the influence of an electron beam can be formed. A positive resist composition for use and an acid dissociable group-containing monomer for use therein are provided.

Claims (17)

A positive resist composition comprising (A) a polymer containing a unit represented by the following formula (1) and (B) a compound which generates an acid by irradiation with radiation: [Formula 1] (Wherein R represents a hydrogen atom or a lower alkyl group, R ¹ represents an alkyl group having 2 or more carbon atoms, n is 0 or 1). The positive type resist composition according to claim 1, wherein the component (A) is a copolymer of a unit represented by the formula (1) with another copolymerizable monomer. The positive type resist composition according to claim 2, wherein said other copolymerizable monomer is at least one member selected from maleic anhydride and polycyclic olefins. The positive type resist composition according to claim 3, wherein said other copolymerizable monomer is maleic anhydride. The positive type resist composition according to claim 3, wherein the unit of the other copolymerizable monomer is at least one of units derived from polycyclic olefins represented by the following general formula (2): [Formula 2] (In formula, R and n are the same as the above, R <^2> is a C1-C10 alkyloxycarbonyl group which has a hydrogen atom, a carboxyl group, or one or more hydroxyl group). The positive type resist composition according to claim 4, wherein the component (A) is a polymer containing a unit represented by the following formula (3): [Formula 3] (Wherein R, R ¹ and n are the same as above). The positive type resist composition according to claim 6, wherein the component (A) is a polymer comprising the units represented by the formula (3) and the formula (4): [Formula 4] (In formula, R is the same as the above, R <^3> is a C1-C10 alkyl group which has a hydroxyl group, m is 0 or 1). The positive type resist composition according to claim 5, wherein the component (A) is a polymer represented by the formula (5) comprising at least three units: [Formula 5] (Wherein R, R ¹ and n are the same as described above, and R ⁴ is an alkyloxycarbonyl group having 1 to 10 carbon atoms having at least one hydroxyl group). The positive type resist composition according to any one of claims 1 to 6 or 8, wherein R ¹ is a lower alkyl group having 2 or more carbon atoms. The positive type resist composition according to claim 7, wherein R ³ is a lower monohydroxyalkyl group or a lower dihydroxyalkyl group. 10. The positive type resist composition according to claim 9, wherein R ¹ is an ethyl group. The positive type resist composition according to claim 10, wherein R ³ is a 2-hydroxypropyl group. The positive resist composition according to any one of claims 1 to 8, further comprising 0.01 to 5% by weight of an organic carboxylic acid or an oxo acid or a derivative thereof of phosphorus based on (A). The positive resist composition according to any one of claims 1 to 8, further comprising 0.01 to 5% by weight of an organic amine relative to (A). The positive type resist composition according to any one of claims 1 to 8, further comprising 5 to 20% by weight of an ester of a bile acid and an acid dissociable group, based on (A). 16. The positive type resist composition according to claim 15, wherein the bile acid ester is tert-butyl ester of cholic acid, deoxycholic acid, ulsocholic acid and lithopholic acid. Acid dissociable group-containing monomer represented by the following formula (6): [Formula 6] (Wherein R represents a hydrogen atom or a lower alkyl group, and R ¹ represents an alkyl group having 2 or more carbon atoms).