JPH10207067A - Positive photoresist composition to be exposed to far ultraviolet rays - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the positive photosresist composition to be exposed to 170-220nm short ultraviolet rays high in transparence in this region, good in light decomposability and acid generation efficiency, high in sensitivity and storage stability, and resistant to dry etching by using a specified copolymer having an alkali-soluble protective group to be decomposed by action of an acid in the molecule. SOLUTION: This photoresist comprises the copolymer having the alkali- soluble protective group decomposable with an acid in the molecule, and a compound to be allowed to release an acid by exposure. This copolymer comprises the repeating units derived from a monomer having an aliphatic cyclic hydrocarbon group in the molecule and the repeating units derived from a monomer represented by the formula in which R1 is an H atom or an alkyl group group; each of R2 -R4 is an alkyl group; and A is a simple bond or an alkylene or ether or thioether group or a combination of optional >=2 of them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for manufacturing semiconductor integrated circuit elements, masks for manufacturing integrated circuits, printed wiring boards, liquid crystal panels, etc., which are suitable for exposure to light having a very short wavelength of 170 to 220 nm. The present invention relates to a positive photoresist composition.

[0002]

2. Description of the Related Art In recent years, in the field of manufacturing various electronic devices that require microfabrication of semiconductor devices and the like, there is an increasing demand for higher density and higher integration of devices. Along with this, the required performance of a photography technique for realizing a fine pattern is extremely severe. Part of this miniaturization technology is to increase the resolution of the photoresist and to shorten the wavelength of the exposure light.

In general, the resolution (Res) of an optical system can be expressed by Rayleigh's equation, that is, Res = k · λ / NA (k is a process factor, λ is the wavelength of an exposure light source, and NA is the numerical aperture of a lens). . From this equation, it can be seen that in order to reduce the reproduction line width and to resolve a fine pattern (that is, to obtain a high resolution), the wavelength at the time of exposure may be shortened. Certainly, with the reduction of the minimum reproduction line width, the exposure wavelength shifts to g-line (436 nm) and i-line (365 nm) of a high-pressure mercury lamp, and furthermore, device manufacturing using a KrF excimer laser (248 nm) is being studied. For further fine processing, use of a shorter-wave excimer laser, especially ArF (193 nm), is considered promising.

On the other hand, turning to the photoresist exposed to the short-wavelength light, instead of a single-layer resist which has conventionally led to production, a multilayer resist system of two or more layers using surface lithography is used. High integration is also being studied. However, the complexity of the process that has hindered the practical use of multilayer resists remains a problem. Also, K
In the case of an excimer laser such as an rF excimer laser, it is generally considered that the cost performance of the laser needs to be improved because the gas life is short and the exposure apparatus itself is expensive in the first place. The answer to this is the so-called chemically amplified resist that has become the mainstream for KrF excimer laser exposure. A chemically amplified resist generates an acid from a photoacid generator present in a catalytic amount in the system upon exposure, and the catalytic amount of the acid catalytically removes the protecting group of the binder or the alkali-soluble group of the low molecular weight compound. The mechanism is to ensure discrimination of solubility in an alkali developing solution. Chemically amplified resists can be expected to have higher sensitivity because they utilize the acid generated by the photoreaction in a catalytic manner.

A chemically amplified resist is generally called a two-component system in which a photoacid generator and a resin having a protecting group for an alkali-soluble group decomposed by the action of an acid are combined.
2.5-component system further containing a low molecular weight compound having a protecting group for an alkali-soluble group decomposed by the action of an acid in the molecule, a photoacid generator and an alkali-soluble resin, an alkali decomposed by the action of an acid It is roughly classified into a three-component system containing a low-molecular compound having a protecting group for a soluble group in the molecule. The copolymer of the present invention corresponds to a resin having a protective group for an alkali-soluble group decomposed by the action of an acid in a molecule (a resin having an acid-decomposable group).

[0006] A new problem arises when the exposure light has a short wavelength. In other words, both the transparency to exposure light and the resistance to dry etching are compatible. Heretofore, binders have been mainly responsible. However, novolak resins which have been widely used as alkali-soluble resins for i-line resists, and poly p-hydroxystyrene which has been used as a base polymer for KrF excimer laser resists, have a target of 170 nm to 220 nm. In such a wavelength region, it cannot be used practically because it has a high optical density. Therefore, development of a resin having optical transparency and high resistance to dry etching has been desired.

One of the answers to this is the introduction of an aliphatic cyclic hydrocarbon site, and another is the use of a naphthalene skeleton, which is one of aromatic compounds. In particular, the fact that dry etching resistance and transparency can be compatible at the same time by the aliphatic cyclic hydrocarbon site is described in the Journal of Photopolymer Science and
technology vol.3, p439, 1992.

[0008] On the other hand, the selection of the acid-decomposable group is particularly important in determining the sensitivity and resolution of the resist, and also the stability over time. Heretofore, tertiary alkyl esters such as t-butyl ester and acetal esters such as tetrahydropyranyl ester and ethoxyethyl ester have been mainly reported as acid-decomposable groups for protecting carboxylic acids. However, the t-butyl ester group as an acid-decomposable group has a disadvantage that sensitivity is lowered due to low elimination ability. On the other hand, tetrahydropyranyl ester,
Ethoxyethyl ester, on the contrary, decomposes even at room temperature, and thus has a serious problem in stability over time. In addition, Patent Document 5-346668 proposes an acid-decomposable group for a 3-oxocyclohexyl ester group, but this is not always satisfactory in terms of sensitivity.

[0009]

As described above, it has not always been clear how to design a protecting group for carboxylic acids which simultaneously satisfies sensitivity and stability over time.
Accordingly, an object of the present invention is to provide a positive type photoresist for deep ultraviolet exposure that is sufficiently transparent to light in a wavelength region of 170 to 220 nm, has dry etching resistance, and has high sensitivity and excellent storage stability. To provide.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies while paying attention to the above characteristics, and have found that a resin having a protective group (acid-decomposable group) of an alkali-soluble group, which decomposes under the action of an acid, in the molecule. The inventors have found that the problems can be solved by introducing an aliphatic cyclic moiety and changing the acid-decomposable group, and have arrived at the present invention based on this finding. That is, the positive photoresist composition according to the present invention has the following constitution. (1) In a positive photoresist composition for deep-ultraviolet light exposure containing a resin having a protective group of an alkali-soluble group decomposed by the action of an acid in a molecule, and a compound capable of generating an acid upon exposure, the action of the acid A resin having a protecting group for an alkali-soluble group that decomposes in the molecule is composed of a repeating unit of a monomer represented by the following general formula [I] and a repeating unit of a monomer having an aliphatic cyclic hydrocarbon moiety in the molecule. A positive photoresist composition for deep ultraviolet exposure, comprising a copolymer containing the same.

[0011]

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In the formula, R ₁ represents a substituent selected from a hydrogen atom and a methyl group. R _{2 to} R ₄ each represent a substituent selected from the group consisting of alkyl groups (which may combine with each other to form a ring). A: a single bond or a single bond selected from the group consisting of an alkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, and a sulfonamide group, or 2
Represents one or more combinations of substituents.

(2) In the above-mentioned copolymer (1), the optical density per 1.0 μm of film thickness to 170-220 nm light in the state of a coating film is 0.40 μm ⁻¹ or less. 4. The positive photoresist composition for deep ultraviolet exposure according to item 1.

Hereinafter, the present invention will be described in detail. R _{2 to} R
The alkyl groups of ₄ may be the same or different,
A lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group is preferable, and a methyl group, an ethyl group, a propyl group, and an isopropyl group are more preferable. Examples of the ring formed by combining two of R _{2 to} R ₄ include a cyclopentyl group, a cyclohexyl group,
And cyclooctyl group. The alkylene group of the linking group A is represented by the following general formula.

[0015]

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In the formula, R ₅ and R ₆ each represent a hydrogen atom or an alkyl group, and they may be the same or different. As the alkyl group, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, And the like, and more preferably represents a substituent selected from the group consisting of a methyl group, an ethyl group, a propyl group, and an isopropyl group. n represents an integer of 1 to 10.

Among the monomers represented by the general formula [I] in the present invention, the compounds represented by the following general formulas are preferred.

[0018]

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[0019] In the formula, R ₁ to R ₄ is R ₁ in the formula [I]
To R ₄ and are each synonymous. General formula [I] in the present invention
Specific examples of the monomer represented by are shown below, but the content of the present invention is not limited thereto.

[0020]

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[0021]

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[0022]

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The monomer of the present invention into which an alkylthiol ester is introduced as a protecting group for an alkali-soluble group which is decomposed by the action of an acid is described in S. Masamune et.al. J. Am. Chem.
Soc., 97, 3515 (1975) and B. Neises et.al, Angew.
It can be synthesized from the corresponding carboxylic acid by the method described in Chem. Int. Ed. Engl. 17, 522 (1978).

Next, the repeating unit of the monomer having an aliphatic cyclic hydrocarbon moiety will be described. The repeating unit of the monomer having an aliphatic cyclic hydrocarbon moiety is represented by, for example, the following general formula [II] or [III].

[0025]

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In the formula, R ₇ represents a substituent selected from the group consisting of a monovalent aliphatic cyclic hydrocarbon substituent.

[0027]

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In the formula, R ₈ represents a linking group selected from the group consisting of linking groups containing a divalent aliphatic cyclic hydrocarbon moiety. X: represents a substituent selected from the group consisting of COOH, OH, COOR ₁₀ and OR ₁₀ .

As the monovalent aliphatic cyclic substituent for R ₇ ,
Examples thereof include an adamantyl group, a norbornyl group, an isobornyl group, a tricyclodecanyl group, a dicyclopentenyl group, a norbornane epoxy group, a cyclohexyl group, and a menthyl group. Examples of the aliphatic cyclic moiety of the linking group containing a divalent aliphatic cyclic moiety of R ₈ include the following partial structures.

[0030]

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Further, the aliphatic cyclic site and an ester residue,
Examples of the linking group in R ₈ connecting the X groups include a single bond, an alkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, and a divalent organic linking group such as a sulfonamide group. However, one or two or more linking groups can be used in combination.
R ₁₀ is t- butyl group, a tertiary alkyl group such as t- amyl group, tetrahydropyranyl group, tetrahydrofuranyl _{group, -CH (CH 3) OCH 2} CH 3, -CH (CH 3) O
CH ₂ CH (CH _{3) 2,} etc. alkoxyethyl group, -CH ₂
It represents a substituent selected from the group consisting of substituents decomposed by the action of an acid such as an alkoxymethyl group such as OCH ₃ and —CH ₂ OCH ₂ CH ₃ .

The repeating unit of a monomer having a thiol ester group in the molecule as a protecting group (acid-decomposable group) for an alkali-soluble group decomposed by the action of an acid represented by the general formula [I] of the present invention and a molecule thereof In the copolymer containing a repeating unit of a monomer having an aliphatic cyclic hydrocarbon moiety in the copolymer, the amount of the repeating unit of the monomer represented by the general formula [I] is 5 based on all the repeating units. Mol% to 80 mol%
And preferably from 10 mol% to 70 mol%. On the other hand, the amount of the monomer containing an aliphatic cyclic hydrocarbon moiety in the molecule is from 95 mol% to 20 mol%, based on all repeating units.
Mol%, preferably 90 mol% to 30 mol%. When the amount of the repeating unit of the monomer represented by the general formula [I] is less than 5 mol%, the effect of the present invention is not exhibited,
On the other hand, when it exceeds 80 mol%, deterioration of dry etching resistance is observed.

In addition to the above monomers, the following monomers can be copolymerized as repeating units.
However, it is not limited to this. Thereby, the performance required for the resin, particularly (1) solubility in a coating solvent,
(2) film-forming properties (glass transition point), (5) alkali developability, film thinning (hydrophobic, alkali-soluble group selection),
Fine adjustment of (6) adhesion of the unexposed portion to the substrate and (7) dry etching resistance is possible.

The following can be mentioned as such a comonomer. For example, it is a compound having one addition-polymerizable unsaturated bond selected from acrylic esters, acrylamides, methacrylic esters, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, and the like. The amount of such a monomer is 99 mol% or less based on the total number of moles of the monomer represented by the general formula [I] and the monomer containing an aliphatic cyclic moiety. It is preferably at most 90 mol%, more preferably at most 80 mol%. When it exceeds 99 mol%, the effect of the present invention is not exhibited.

Specific examples of such other monomers include, for example, acrylates, for example, alkyl (alkyl having preferably 1 to 10 carbon atoms) acrylate (for example, methyl acrylate) , Ethyl acrylate, propyl acrylate, amyl acrylate, ethyl hexyl acrylate, octyl acrylate, tert-octyl acrylate, chloroethyl acrylate, 2-hydroxyethyl acrylate 2,2-dimethylhydroxypropyl acrylate, 5-hydroxypentyl Acrylate, trimethylolpropane monoacrylate, pentaerythritol monoacrylate, etc.);

Methacrylic esters, for example, alkyl (alkyl having preferably 1 to 10 carbon atoms) methacrylate (for example, methyl methacrylate,
Ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, t-butyl methacrylate,
Amyl methacrylate, hexyl methacrylate, octyl methacrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 2,2-dimethyl-3
-Hydroxypropyl methacrylate, trimethylolpropane monomethacrylate, pentaerythritol monomethacrylate, etc.);

Acrylamides, for example, acrylamide, N-alkylacrylamide, (alkyl having 1 to 10 carbon atoms, for example, methyl, ethyl, propyl, butyl, t-butyl, heptyl, octyl Group, cyclohexyl group, benzyl group, hydroxyethyl group, benzyl group, etc.) N, N-dialkylacrylamide (alkyl group having 1 to 10 carbon atoms, for example, methyl group, ethyl group, butyl group, isobutyl Group, ethylhexyl group, cyclohexyl group, etc.), N-hydroxyethyl-N-methylacrylamide, N-2-acetamidoethyl-N-acetylacrylamide and the like;

Methacrylamides, for example, methacrylamide, N-alkylmethacrylamide (the alkyl group having 1 to 10 carbon atoms, for example, methyl, ethyl, t-butyl, ethylhexyl, hydroxyethyl, cycloethyl) Groups, etc.), N, N-dialkylmethacrylamide (an alkyl group includes an ethyl group, a propyl group, a butyl group, etc.), N-hydroxyethyl-N-methylmethacrylamide and the like;

Allyl compounds such as allyl esters (eg, allyl acetate, allyl caproate, allyl caprylate, allyl laurate, allyl acetoacetate, allyl lactate, etc.), allyloxyethanol and the like;

Vinyl ethers such as alkyl vinyl ethers (eg, hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, chloroethyl vinyl ether, 1-methyl-2,2-dimethylpropyl vinyl ether, 2-ethyl Butyl vinyl ether, hydroxyethyl vinyl ether, diethylene glycol vinyl ether, dimethylaminoethyl vinyl ether, diethylaminoethyl vinyl ether, butylaminoethyl vinyl ether, benzyl vinyl ether, tetrahydrofurfuryl vinyl ether, etc.); dialkyl esters of maleic acid or fumaric acid (eg, dimethyl maleate, dibutyl) Malate, etc.), or monoalkyl esters, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic anhydride, maleimide, acrylonitrile, methacrylonitrile, there are maleylonitrile. In addition, any addition-polymerizable unsaturated compound copolymerizable with the repeating unit represented by the general formula [I] may be used.

Examples of the copolymer of the present invention include, but are not limited to, those represented by the following general formula.

[0042]

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In the formula, R _{1 to} R ₄ , R ₇ , R ₈ , A and X represent the same as described above. R ₉ : represents a tertiary alkyl group, a tetrahydropyranyl group, a tetrahydrofuranyl group, an alkoxyethyl group, an alkoxymethyl group, a 3-oxocyclohexyl group, or a 2-oxocyclohexyl group. R _{20 represents a} methyl group, an ethyl group, a propyl group, an ISO propyl group, or an n-butyl group. a: 5 to 80 b: 0 to 70 c: 0 to 95 d: 0 to 50 e: 0 to 50 f: 0 to 50 a + d ≧ 30, b + c ≧ 50, a + b + c + d + e + f
= 100.

The weight average molecular weight of the copolymer of the present invention is 2,
000-200,000. Weight average molecular weight of 2,
If it is less than 000, heat resistance and dry etching resistance are deteriorated, so that it is not preferable. If it exceeds 200,000, developability is deteriorated and viscosity becomes extremely high, so that film forming property is deteriorated. In the present invention, in the resin having an acid-decomposable group, the optical density with respect to exposure light having a wavelength of 170 to 220 nm is preferably 0.35 μm ⁻¹ or less, more preferably 0.32 μm ⁻¹ or less, and still more preferably 0 or less. .30 μm ⁻¹ or less. In addition to the resin and a photoacid generator, a photosensitive resin composition, when it is deposited the composition, the optical density is at 0.40 .mu.m ^-1 or less, preferably 0.36 .mu.m ^-1 or less, more Preferably it is 0.32 μm ⁻¹ or less. Here, the above optical density is obtained by dissolving a resin having an acid-decomposable group or a resin having a photo-acid generator and an acid-decomposable group in a resist coating solvent described later, coating on a quartz substrate, and drying to form a film. Is a value obtained by measuring the optical density per 1.0 μm of the coating film obtained by using an ultraviolet absorption measuring device.

Further, in the copolymer composition of the present invention containing the repeating unit of the monomer represented by the general formula [I] and the repeating unit of the monomer having an aliphatic cyclic hydrocarbon moiety in the molecule. Is 40 to 99% by weight, preferably 50 to 97% by weight, based on the total solid content.

The copolymer of the present invention can be synthesized by a usual method such as radical polymerization using an azo compound or the like as an initiator. Next, the copolymer of the present invention containing a repeating unit of a monomer represented by the general formula [I] and a repeating unit of a monomer having an aliphatic cyclic hydrocarbon moiety in the molecule is a photoacid generator. To form a positive photoresist.

Next, the photoacid generator will be described. The necessary requirements for the photoacid generator are (1) transparency to exposure light (if there is no photobleaching property), and (2) sufficient photodegradability to ensure resist sensitivity, which is contradictory. Performance is required. However, at present, the molecular design guideline that satisfies the contradictory essential requirements is not clear, but the following compounds can be mentioned as the photoacid generator of the present invention. For example, Japanese Patent Application Laid-Open No. 7-2584
6, JP-A-7-28237, JP-A-7-9
2675, and JP-A-8-27102.
-Aliphatic alksulfonium salts having an oxcyclohexyl group, and N-hydroxysuccinimide sulfonates, and also J. Photopolym. Sci. Tec.
hnol., Vol 7, No. 3, p 423 (1994), etc., sulfonium salts represented by the following general formula [IV], disulfones represented by the following general formula [V], and compounds represented by the following general formula [VI] Compounds to be used can be mentioned.

[0048]

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In the formula, R _{14 to} R ₁₇ may be the same or different and represent an alkyl group or a cyclic alkyl group.

The following N-hydroxymaleimide sulphonates are also suitable.

[0051]

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In the formula, R ₁₁ and R ₁₂ may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group (provided that R ₁₁ and R ₁₂ are R ₁₃ may represent an alkyl group, a perfluoroalkyl group, or a cycloalkyl group. In particular, N-hydroxymaleimide sulphonates are preferred in terms of sensitivity.

The carbon number of R ₁₁ and R ₁₂ in the above general formula is 1
Examples of the 6 to 6 alkyl groups include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group. Among them, preferred are a methyl group, an ethyl group and a propyl group, and a methyl group and an ethyl group are more preferred. Examples of the cycloalkyl group having 6 or less carbon atoms include a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group. Preferably, they are a cyclopentyl group and a cyclohexyl group. Examples of a case where R ₁₁ and R ₁₂ form a ring with each other by an alkylene chain include a case where a cyclohexyl group, a norbornyl group, and a tricyclodecanyl group are formed.

Examples of the alkyl group for R ₁₃ include a linear alkyl group having 1 to 20 carbon atoms such as a methyl group, an ethyl group and a propyl group, an isopropyl group, an isobutyl group and a te group.
Examples thereof include a branched alkyl group having 1 to 20 carbon atoms such as an rt-butyl group and a neopentyl group.
It is preferably a straight-chain or branched alkyl group having 1 to 16 carbon atoms, and more preferably a straight-chain or branched alkyl group having 4 to 15 carbon atoms. Examples of the perfluoroalkyl group include a trifluoromethyl group, a linear perfluoroalkyl group having 1 to 20 carbon atoms such as a pentafluoroethyl group, and a branched group including a heptafluoroisopropyl group and a nonafluorotert-butyl group. And a perfluoroalkyl group having 1 to 20 carbon atoms. Preferably, it is a linear or branched perfluoroalkyl group having 1 to 16 carbon atoms. Examples of the cyclic alkyl group include a monocyclic cyclic alkyl group such as a cyclopentyl group and a cyclohexyl group, and a plural cyclic alkyl group such as a decalyl group, a norbornyl group, and a tricyclodecanyl group.

The amount of the photoacid generator to be added is 0.1 to 20% by weight, preferably 0.5 to 15% by weight, more preferably 1 to 10% by weight based on the total solid content of the positive photoresist. It is. Further, in addition to the photoacid generator, a photoacid generator as shown below may be used in combination. However, when these photoacid generators are used in combination, the added amount should be 2% by weight or less based on the whole resist solids. More preferably, it is at most 1% by weight.

Examples of such a photoacid generator include, for example,
SISchlesinger, Photogr. Sci. Eng., 18, 387 (1974), T.
Diazonium salts described in S. Bal et al., Polymer, 21, 423 (1980), U.S. Pat.Nos. 4,069,055, 4,069,056,
Re 27,992, ammonium salt described in Japanese Patent Application No. 3-140,140, DC Necker et al., Macromolecules, 17, 2468 (198
4) 、 CSWen etal, Teh, Proc.Conf.Rad.Curing ASIA, p47
8 Tokyo, Oct (1988), U.S. Pat.Nos. 4,069,055 and 4,06
Phosphonium salt described in 9,056, etc., JVCrivelloeta
l, Macromorecules, 10 (6), 1307 (1977), Chem. & Eng. New
s, Nov. 28, p31 (1988), European Patent No. 104,143, U.S. Patent Nos. 339,049, 410,201, JP-A-2-150,848,
Iodonium salts described in JP-A-2-296,514, etc., JVCr
ivello etal, Polymer J. 17, 73 (1985), JVCrivello e
tal.J.Org.Chem., 43, 3055 (1978), WRWatt et al., J. Po.
lymer Sci., Polymer Chem. Ed., 22, 1789 (1984), JVCr
ivelloetal, Polymer Bull., 14,279 (1985), JVCrivell
o etal, Macromorecules, 14 (5), 1141 (1981), JVCrive
llo etal, J. Polymer Sci., Polymer Chem. Ed., 17, 2877 (19
79), European Patent Nos. 370,693, 3,902,114, 233,5
Nos. 67, 297,443 and 297,442, U.S. Pat.
3,377, 161,811, 410,201, 339,049
Nos. 4,760,013, 4,734,444, 2,833,827
No. 2,904,626, 3,604,580, 3,60
No. 4,581, etc., sulfonium salt, JVCrivello eta
l, Macromorecules, 10 (6), 1307 (1977), JVCrivello e
tal, J. PolymerSci., Polymer Chem. Ed., 17,1047 (1979)
Selenonium salts, CSwen et al, Teh, Proc.Co
Onium salts such as arsonium salts described in nf.Rad.Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat.
No., JP-B-46-4605, JP-A-48-36281, JP-A-55-3
No. 2070, JP-A-60-239736, JP-A-61-169835, JP-A-61-169837, JP-A-62-58241, JP-A-62-21240
No. 1, JP-A-63-70243, and organic halogen compounds described in JP-A-63-298339, K. Meier et al., J. Rad.
(4), 26 (1986), TPGill et al., Inorg.Chem., 19, 3007 (1
980), D. Astruc, Acc. Chem. Res., 19 (12), 377 (1896), and organic metal / organic halides described in JP-A-2-14145, etc., S. Hayase et al., J. Polymer Sci. ., 25, 753 (1987), E.
Reichmanis etal, J.Pholymer Sci., Polymer Chem.Ed., 2
3,1 (1985), QQZhu et al., J. Photochem., 36, 85, 39, 317
(1987), B. Amit etal, Tetrahedron Lett., (24) 2205 (197
3), DHR Barton et al., J. Chem Soc., 3571 (1965) ³ PMC
ollins et al., J. Chem. SoC., PerkinI, 1695 (1975), M. Rudi
nstein et al, Tetrahedron Lett., (17), 1445 (1975), J.
W. Walker et al. J. Am. Chem. Soc., 110, 7170 (1988), SCBu
sman et al, J. Imaging Technol., 11 (4), 191 (1985), HM
Houlihan et al, Macormolecules, 21, 2001 (1988), PMCol
lins et al., J. Chem. Soc., Chem. Commun., 532 (1972), S. Hay
ase etal, Macromolecules, 18, 1799 (1985), E. Reichmani
s etal, J.Electrochem.Soc., SolidState Sci.Technol.,
130 (6), FMHoulihan et al, Macromolcules, 21, 2001 (19
88), European Patent Nos. 0290,750, 046,083, 156,535
No. 271,851, No. 0,388,343, U.S. Pat.
Nos. 710, 4,181,531, JP-A-60-198538, JP-A-60-198538
53-133022, etc., a photoacid generator having an o-nitrobenzyl-type protecting group, M. TUNOOKA etal, Polymer Preprint
s Japan, 35 (8), G. Berner et al., J. Rad. Curing, 13 (4), W.
J.Mijs etal, Coating Technol., 55 (697), 45 (1983), Akzo
³ H. Adachietal, Polymer Preprints, Japan, 37 (3), European Patent Nos. 0199,672, 84515, 199,672, 044,
No. 115, No. 0101,122, U.S. Pat.No. 618,564, No. 4,37
Nos. 1,605, 4,431,774, JP-A-64-18143, JP-A-2
-245756, compounds that generate sulfonic acid upon photolysis, such as iminosulfonates described in Japanese Patent Application No. 3-140109, and disulfone compounds described in JP-A-61-166544. Can be.

Further, a group that generates an acid by these lights,
Alternatively, a compound having a compound introduced into a main chain or a side chain of a polymer, for example, MEWoodhouse et al., J. Am. Chem.
c., 104, 5586 (1982), SPPappas et al, J. Imaging Sc
i., 30 (5), 218 (1986), S. Kondoetal, Makromol.Chem., Ra
pid Commun., 9,625 (1988), Y.Yamadaetal, Makromol.Che
m., 152, 153, 163 (1972), JVCrivello etal, J. Polymer
Sci., Polymer Chem. Ed., 17, 3845 (1979), U.S. Pat.
3,849,137, Dokoku Patent No. 3914407, JP-A-63-26653
No., JP-A-55-164824, JP-A-62-69263, JP-A-63
-146038, JP-A-63-163452, JP-A-62-153853
And the compounds described in JP-A-63-146029 and the like can be used.

Further, VNRPillai, Synthesis, (1), 1 (198
0), A. Abad etal, Tetrahedron Lett., (47) 4555 (1971),
DHR Barton et al., J. Chem. Soc., (C), 329 (1970), U.S. Pat. No. 3,779,778, EP 126,712, and the like, can also be used compounds which generate an acid by light.

Among the compounds which can be used together and decompose upon irradiation with actinic rays or radiation to generate an acid, those which are particularly effectively used are described below. (1) The following general formula (PAG) substituted with a trihalomethyl group
The oxazole derivative represented by 1) or the general formula (PA)
An S-triazine derivative represented by G2).

[0060]

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In the formula, R ²⁰¹ is a substituted or unsubstituted aryl group or alkenyl group, and R ²⁰² is a substituted or unsubstituted aryl group, alkenyl group, alkyl group, —C (Y) ₃
Show Y represents a chlorine atom or a bromine atom. Specific examples include the following compounds, but the present invention is not limited thereto.

[0062]

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[0063]

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[0064]

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(2) An iodonium salt represented by the following formula (PAG3) or a sulfonium salt represented by the following formula (PAG4).

[0066]

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In the formula, Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aryl group. In the formula, preferred substituents include an alkyl group, a haloalkyl group, a cycloalkyl group, an aryl group, an alkoxy group, a nitro group, a carboxyl group, an alkoxycarbonyl group, a hydroxy group, a mercapto group, and a halogen atom.

R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ each independently represent a substituted or unsubstituted alkyl group or aryl group. Preferably, an aryl group having 6 to 14 carbon atoms, 1 to 8 carbon atoms
And substituted derivatives thereof. Preferred substituents are those having 1 to 8 carbon atoms for the aryl group.
And an alkyl group having 1 to 8 carbon atoms, a nitro group, a carboxyl group, a hydroxy group and a halogen atom, and an alkyl group is an alkoxy group having 1 to 8 carbon atoms, a carboxyl group and an alkoxycarbonyl group. .

[0069] Z ^- represents a counter anion, CF ₃ SO ₃ ^-
And the like, such as perfluoroalkanesulfonic acid anions and pentafluorobenzenesulfonic acid anions.

Further, two of R ²⁰³ , R ²⁰⁴ and R ²⁰⁵ and Ar ¹ and Ar ² may be bonded through a single bond or a substituent.

Specific examples include the following compounds, but are not limited thereto.

[0072]

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[0073]

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[0074]

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[0075]

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[0076]

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[0077]

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[0078]

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[0079]

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The above onium salts represented by the general formulas (PAG3) and (PAG4) are known, for example, JWKnapcz
yk etal, J. Am. Chem. Soc., 91, 145 (1969), ALMaycoke
tal, J. Org.Chem., 35, 2532, (1970), E. Goethas et al, Bu
ll.Soc.Chem.Belg., 73,546, (1964), HM Leicester,
J. Ame. Chem. Soc., 51, 3587 (1929), JVCrivello etal,
J. Polym. Chem. Ed., 18,2677 (1980), U.S. Pat.
It can be synthesized by the methods described in JP-A Nos. 8 and 4,247,473 and JP-A-53-101,331.

(3) Disulfone derivatives represented by the following general formula (PAG5) or iminosulfonate derivatives represented by the following general formula (PAG6).

[0082]

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In the formula, Ar ³ and Ar ⁴ each independently represent a substituted or unsubstituted aryl group. R ²⁰⁶ represents a substituted or unsubstituted alkyl group or aryl group. A represents a substituted or unsubstituted alkylene group, alkenylene group, or arylene group. Specific examples include the following compounds, but are not limited thereto.

[0084]

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[0085]

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[0086]

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[0087]

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[0088]

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The purpose of the photosensitive resin composition of the present invention is to improve the alkali solubility of the system and to adjust the glass transition temperature of the system to prevent the film from becoming brittle and from deteriorating the heat resistance. And an appropriate alkali-soluble low molecular weight compound may be added. Examples of the alkali-soluble low molecular weight compound include a dialkyl sulfonamide compound, a dialkyl sulfonyl imide (—SO ₂ —NH—CO—) compound, and a dialkyl disulfonyl imide (—SO ₂ —NH
Compounds containing an acidic group in the molecule, such as —SO ₂ —) compounds, may be mentioned. The content of the alkali-soluble low molecular weight compound is, based on the resin having a substituent that increases the solubility in an alkali developer by the acid,
40% by weight or less is preferable, and 30% by weight is more preferable.
Or less, more preferably 25% by weight or less.

The solvent used in the present invention is preferably one in which the component comprising the above-mentioned polymer compound and the photoacid generator of the present invention is sufficiently dissolved, and the solution is uniformly coated by a method such as spin coating. Any solvent may be used as long as it can form an organic solvent. Moreover, you may use individually or in mixture of 2 or more types. Specifically, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol,
Tert-butyl alcohol, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monoethyl ether acetate, methyl lactate, ethyl lactate, 2-methoxybutyl acetate, 2-ethoxyethyl acetate, methyl pyruvate, ethyl pyruvate, 3-methoxypropion Acid methyl, ethyl 3-methoxypropionate, N-methyl-2-pyrrolidinone, cyclohexanone, cyclopentanone, cyclohexanol, methyl ethyl ketone, 1,4-dioxane, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl Ether, ethylene glycol monoisopropyl ether, diethylene glycol monomethyl ether, diethylene glycol Ether, and the like, but the invention is of course not limited thereto.

The “basic” components of the photosensitive resin composition of the present invention include the above-mentioned photoacid generator, the above-mentioned polymer compound,
Although it is a solvent (an alkali-soluble low molecular weight compound as required), other components such as a surfactant, a dye, a stabilizer, a coating improver, and a dye may be added as needed.

In the case where a fine pattern is formed by using the present invention, an appropriate organic solvent or a mixed solvent thereof or an appropriate solvent depending on the solubility of the polymer compound used in the present invention is used. An alkaline solution, an aqueous solution or a mixture thereof having a concentration, or a mixture of an alkaline solution and an appropriate organic compound or organic solvent may be selected. Organic solvents and organic compounds used include, for example, acetone,
Ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, 2,6-dimethylcyclohexanone, 3-methyl-2-cyclopentanone, methyl alcohol, ethyl alcohol, n
-Propyl alcohol, isopropyl alcohol, n-
Butyl alcohol, isobutyl alcohol, tert-
Alcohols such as butyl alcohol, cyclopentanol, cyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 3,5-dimethylcyclohexanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, etc. ,
Organic solvents such as tetrahydrofuran, dioxane, ethyl acetate, butyl acetate, isoamyl acetate, benzene, toluene, xylene, phenol, acetonitrile, dimethylformamide and the like. Examples of the alkaline solution used include, for example, inorganic alkalis such as sodium hydroxide, potassium hydroxide, sodium silicate, and ammonia; and organic acids such as ethylamine, propylamine, diethylamine, dipropylamine, trimethylamine, and triethylamine. An aqueous solution or an organic solvent containing amines, and an organic ammonium salt such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylhydroxymethylammonium hydroxide, triethylhydroxymethylammonium hydroxide, trimethylhydroxyethylammonium hydroxide, or the like; And mixtures thereof, but is not limited thereto.

The photosensitive resin composition of the present invention is applied on a substrate to form a thin film. The thickness of this coating film is 0.4-1.
5 μm is preferred. In the present invention, any exposure means such as ArF excimer laser stepper exposure may be used as long as the exposure wavelength is in the range of 170 to 220 nm, and an ArF excimer laser stepper is particularly preferred.

[0094]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples, but of course, the scope of the present invention is not limited thereto. (1) Synthesis of Monomer a According to Angew. Chem. Int. Ed. Engl. 17, 522 (1978), acrylic acid was reacted with t-butylthiol, and the resulting reaction mixture was purified by silica gel column chromatography. Then, the target monomer a was synthesized. (2) Synthesis of Monomer b According to Angew. Chem. Int. Ed. Engl. 17, 522 (1978), light ester HO-MS manufactured by Kyoeisha Chemical was reacted with -butylthiol, and the resulting reaction mixture was silica gel. The product was purified by column chromatography to synthesize the desired monomer b.

(3) Synthesis of Resin A Tricyclodecanyl acrylate 10.3 g Monomer a 4.3 g Acrylic acid 1.4 g After dissolving 25.0 g of THF (tetrahydrofuran), the reaction was carried out while flowing nitrogen for 30 minutes. 65 liquid
Heated to ° C. As a polymerization initiator, 25 mg of V-65 (a product of Wako Pure Chemical Industries, Ltd.) was added every 5 hours in 5 divided portions. After adding the final initiator, it was heated for 4 hours. After the heating was completed, the reaction solution was returned to room temperature, 50 g of THF was added, and the diluted reaction solution was reprecipitated in 3 L of hexane to recover the desired copolymer as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 28,000 in terms of standard polystyrene.

(4) Synthesis of Resin B Tricyclodecanyl acrylate 10.3 g Monomer b 9.1 g Acrylic acid 1.4 g After dissolving 30.0 g of THF, the reaction solution was cooled to 65 while flowing nitrogen for 30 minutes.
Heated to ° C. As a polymerization initiator, 25 mg of V-65 (a product of Wako Pure Chemical Industries, Ltd.) was added every 5 hours in 5 divided portions. After adding the final initiator, it was heated for 4 hours. After the heating was completed, the reaction solution was returned to room temperature, 50 g of THF was added, and the diluted reaction solution was reprecipitated in 3 L of hexane to recover the desired copolymer as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 31,000 in terms of standard polystyrene.

(5) Synthesis of Resin C After synthesizing a monomer c having the following structure by a method according to the method described in JP-A-8-259626,

[0098]

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After dissolving 6.2 g of tricyclodecanyl acrylate, 4.3 g of monomer a, 10.6 g of monomer c, and 32 g of THF, the reaction solution was cooled to 65 while flowing nitrogen for 30 minutes.
Heated to ° C. As a polymerization initiator, 25 mg of V-65 (a product of Wako Pure Chemical Industries, Ltd.) was added every 5 hours in 5 divided portions. After adding the final initiator, it was heated for 4 hours. After the heating was completed, the reaction solution was returned to room temperature, 50 g of THF was added, and the diluted reaction solution was reprecipitated in 4 L of hexane to recover the desired copolymer as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 34,000 in terms of standard polystyrene.

(6) Synthesis of Comparative Resin D Tricyclodecanyl acrylate 10.3 g t-butyl acrylate 3.9 g Acrylic acid 1.4 g THF 24.0 g was dissolved, and then the reaction solution was supplied while flowing nitrogen for 30 minutes. To 65
Heated to ° C. As a polymerization initiator, 25 mg of V-65 (a product of Wako Pure Chemical Industries, Ltd.) was added every 5 hours in 5 divided portions. After adding the final initiator, it was heated for 4 hours. After the heating was completed, the reaction solution was returned to room temperature, 50 g of THF was added, and the diluted reaction solution was reprecipitated in 3 L of hexane to recover the desired copolymer as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 24,000 in terms of standard polystyrene.

(7) Synthesis of Comparative Resin E Tricyclodecanyl acrylate 10.3 g Tetrahydrofuranyl acrylate 4.8 g Acrylic acid 1.4 g After dissolving 25 g of THF, the reaction solution was cooled to 65 while flowing nitrogen for 30 minutes.
Heated to ° C. As a polymerization initiator, 25 mg of V-65 (a product of Wako Pure Chemical Industries, Ltd.) was added every 5 hours in 5 divided portions. After adding the final initiator, it was heated for 4 hours. After the heating was completed, the reaction solution was returned to room temperature, 50 g of THF was added, and the diluted reaction solution was reprecipitated in 3 L of hexane to recover the desired copolymer as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 29000 in terms of standard polystyrene.

(8) Synthesis of Comparative Resin F Tricyclodecanyl acrylate 10.3 g 3-oxocyclohexyl acrylate 5.2 g Acrylic acid 1.4 g After dissolving 25 g of THF, the reaction solution was fed while flowing nitrogen for 30 minutes. To 65
Heated to ° C. As a polymerization initiator, 25 mg of V-65 (a product of Wako Pure Chemical Industries, Ltd.) was added every 5 hours in 5 divided portions. After adding the final initiator, it was heated for 4 hours. After the heating was completed, the reaction solution was returned to room temperature, 50 g of THF was added, and the diluted reaction solution was reprecipitated in 3 L of hexane to recover the desired copolymer as a white powder. GPC analysis of the obtained copolymer showed that the weight average molecular weight was 31,000 in terms of standard polystyrene.

(9) Synthesis of photoacid generator-1 8 g of sodium hydroxide and 14 g of hydroxyamine hydrochloride
Was dissolved in 200 mL of distilled water, 25 g of dimethylmaleic anhydride was added, and the mixture was stirred at room temperature for 5 hours.
The mixture was heated and stirred at ℃ for 3 hours. After completion of the reaction, aqueous hydrochloric acid was added,
After saturated with sodium chloride, the mixture was extracted with ethyl acetate. The operation of concentrating the obtained ethyl acetate solution to 1/3, adding toluene and concentrating again was repeated to obtain 15 g of N-hydroxymaleimide.

Next, 4.2 g of the N-hydroxymaleimide obtained above was dissolved in dichloromethane, and 8.5 g of trifluoromethanesulfonic anhydride was added thereto while cooling with water.
It was dropped over time. Furthermore, after 2.8 g of topidine was added dropwise over 2 hours, the ice bath was removed, and the temperature was raised to room temperature and the mixture was stirred for 10 hours. After completion of the reaction, the reaction solution was washed with distilled water and the like, concentrated, crystallized in hexane, and the hexane layer was concentrated to obtain 10 g of the desired product. ^{The following} structure was confirmed from ¹³ CNMR and the like.

[0105]

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(10) Preparation of Positive Photoresist 1.2 g of resins A to F synthesized in the above synthesis example, photoacid generator-1 and triphenylsulfonium trifluoromethanesulfonate (acid generator-2) 1g PGM
After dissolving in EA (propylene glycol monoethyl ether acetate) to a solid content of 14%, the solution was filtered through a 0.1 μm microfilter to prepare a positive photoresist composition. The obtained resist solution was applied on a silicon wafer using a spin coater and dried at 120 ° C. for 90 seconds to form a resist film of about 0.5 μm.
3. ArF excimer laser exposure was performed for Comparative Examples 1 to 3, and KrF excimer laser exposure was performed for Examples 4 to 6 and Comparative Examples 4 to 6. After a heat treatment after exposure at 100 ° C. for 90 seconds, development with a 2.38% aqueous solution of tetramethylammonium hydroxide and rinsing with distilled water were performed to obtain a resist pattern profile.

(11) Measurement of Optical Density Resins A to C of the present invention synthesized as described above, m / p-cresol novolak resin, or VP- manufactured by Nippon Soda Co., Ltd.
1 g of each of 800 was dissolved in 2-heptanone to obtain a solution having a solid concentration of 15%. This solution was filtered through a 0.20μ filter. This polymer solution was applied on a quartz glass substrate using a spinner, dried at 120 ° C. for 60 seconds,
A 1.0 μm film was produced. The optical density at 193 nm of the coating film thus obtained was measured using an ultraviolet absorbing device. The results are shown below. Resin A: 0.11μ ^-1 Resin B: 0.13 microns ^-1 Resin C: 0.10μ ^-1 m / p- cresol novolac resin: 1.0 micron ^-1 Nippon Soda Ltd., VP-8000: 1.0μ ^{- As} described above, the resin of the present invention has high transparency in the exposure wavelength range of 170 to 220 nm, which is the target exposure wavelength range of the present invention, while the novolak resin used in conventional i-line resists and the like It has been revealed that polyhydroxystyrene resin widely used as a resin for a KrF excimer laser resist has a problem in transparency.

(12) Evaluation of sensitivity The sensitivity is defined as the exposure amount that reproduces a large pattern of 1.0 μm.
Regarding the ArF excimer laser-exposed product, the relative sensitivity with the resist sensitivity of Example 1 as 1 (sensitivity other than Example 1 /
(Sensitivity of Example 1). The KrF excimer laser-exposed product was expressed as relative sensitivity (sensitivity other than Example 4 / sensitivity of Example 4) with the resist sensitivity of Example 4 set to 1.

With respect to the stability over time, the prepared resist was stored at 30 ° C. for one month, the above-mentioned sensitivity was measured, and the rate of change from the sensitivity before storage and the profile of the unexposed portion were measured with a scanning electron microscope (SEM). ), The film thickness after development is measured, the change in film thickness before and after development is measured before and after storage over time, and the same variation in the amount of film thinning is the rate of change divided by the film thickness before exposure. Evaluated by rate.

[0110]

[Table 1]

As is clear from the results, satisfactory results were obtained with respect to the sensitivity, the sensitivity variation with time, and the film thickness variation rate of the positive photoresist of each of the examples according to the present invention. The positive photoresist of each comparative example had a problem in some results.

[0112]

The positive photoresist composition for exposure to far ultraviolet rays containing the copolymer of the present invention has high sensitivity and is excellent in stability over time, in particular, sensitivity fluctuation over time and suppression of film thinning. It is suitable for use as a material for lithography utilizing light of 170 to 220 nm.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/027 H01L 21/30 502R

Claims (2)

[Claims] A positive photoresist composition for deep-ultraviolet light exposure, comprising a resin having a protective group of an alkali-soluble group capable of decomposing by the action of an acid in a molecule thereof, and a compound capable of generating an acid upon exposure, comprising: A resin having a protective group of an alkali-soluble group which decomposes by an action in the molecule is a repeating unit of a monomer represented by the following general formula [I] and a repeating unit of a monomer having an aliphatic cyclic hydrocarbon moiety in the molecule. A positive photoresist composition for deep ultraviolet exposure, which is a copolymer containing units. Embedded image In the formula, R ₁ represents a substituent selected from a hydrogen atom and a methyl group. R _{2 to} R ₄ each represent a substituent selected from the group consisting of alkyl groups (which may combine with each other to form a ring). A: a single bond or a single bond selected from the group consisting of an alkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, and a sulfonamide group, or 2
Represents one or more combinations of substituents. 2. The copolymer according to claim 1, wherein
The positive photoresist composition for deep-ultraviolet light exposure according to claim 1, wherein the optical density per 1.0 µm of film thickness for light of 70 to 220 nm is 0.40 µm ^-1 or less.