JPH10171121A - Positive type photoresist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the adhesion of an unexposed part and to suppress reduction in the film thickness of the part without deteriorating dry etching resistance improved by alicyclic org. groups by incorporating a polymer contg. a specified structure as repeating units and a compd. which generates an acid when irradiated with active light, etc. SOLUTION: This photoresist compsn. contains a polymer contg. a structure represented by formula I as repeating units and a compd. which is degraded and generates an acid when irradiated with active light or radiation. In the formula I, R1 is H or alkyl, preferably methyl or ethyl. A copolymer contg. a structure represented by the formula I and a structure represented by formula II as repeating units may be contained in place of the polymer. In the formula II, R2 is monovalent alicyclic hydrocarbon such as adamantyl or norbornyl. This compsn. has high sensitivity, ensures slight reduction in the film thickness of the unexposed part, is excellent in adhesion to the substrate and can be used as a material for lithography utilizing light of 170-220nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION
The present invention relates to a positive photoresist composition suitable for exposure to light having a very short wavelength of nm, specifically a novel monomer having a protecting group for an alkali-soluble group which decomposes under the action of an acid in a molecule. It is a copolymer containing a polymer as one of the repeating units.

[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 protecting group for an alkali-soluble group decomposed by the action of an acid in the molecule (a resin having an acid-decomposable group).
The resin having an acid-decomposable group is required to have the following points. (1) Solubility in coating solvent (2) Film-forming property (glass transition point) (3) Transparency to exposure light (4) Decomposability of acid-decomposable group to generated acid (5) Alkaline developability, film thinning (affinity) (Selection of aqueous or alkali-soluble groups) (6) Adhesion of unexposed portion to substrate (7) Dry etching resistance

As for the dry etching resistance (7), a high dry etching resistance of an aromatic ring has been used. For example, novolak resins and polyhydroxystyrenes can be mentioned. However, generally, the aromatic ring is a target of the present invention of 170 to 2.
It has high light absorption in a 20 nm region, and this absorption hardly changes after exposure (no light bleaching property), and thus it is not suitable from the viewpoint of (3) transparency to exposure light. Therefore, development of a resin having optical transparency and high resistance to dry etching has been desired. One answer to this is the introduction of aliphatic cyclic compounds, and another is the use of the naphthalene skeleton, one of the aromatic compounds. The ability of aliphatic cyclic compounds to achieve both dry etching resistance and transparency has been reported in the Journal of Photopolymer Science an
There are many reports including d technology, vol 3, p439, 1992.

On the other hand, attention is paid to the acid-decomposable group.
-346668, a copolymer containing, as one of the repeating units, a monomer having a pendant 3-oxocyclohexyl ester group as an acid-decomposable group;
A copolymer containing, as one of repeating units, a monomer having a pendant oxocyclohexyl ester group and a monomer having a pendant alicyclic organic group for the purpose of improving dry etching resistance has been proposed. 234511
In the above, a monomer having a pendant acid-decomposable group such as a t-butyl ester group, a tetrahydropyranyl ester group or a 3-oxocyclohexyl ester group and a monomer having a pendant alicyclic organic group as one of the repeating units is used. Polymers have been proposed.

However, there is a problem in securing dry etching resistance with an aliphatic cyclic compound. One is that the developability in an aqueous system is deteriorated due to high hydrophobicity. To address this, for example, an attempt has been made to solve the problem by adding alcohol to the developer (SPIE vol.2438, p.422, 19).
95). The other is that the adhesiveness to the substrate in the unexposed portion is deteriorated. This substrate adhesion has been improved mainly by the addition of a monomer having a pendant carboxylic acid or hydroxyethyl group. However, in the copolymerization of a carboxylic acid monomer (methacrylic acid), the adhesion after alkali development has been improved. The damage of the pattern profile and the deterioration of dry etching resistance are serious, and the copolymerization of hydroxyethyl group monomer (hydroxyethyl methacrylate) is completely satisfactory because some exposed areas are negative. No results were obtained.

[0010]

As described above, among the properties required for a resin having an acid-decomposable group in a chemically amplified resist composition, (5) alkali developability, film loss (hydrophobicity, alkali solubility, (Group selection) (6) Adhesion of unexposed portion to substrate (7) Dry etching resistance is not compatible with the current situation.
Therefore, an object of the present invention is to provide a positive photoresist composition that can improve the adhesion and film thinning of an unexposed portion without significantly deteriorating the dry etching resistance improved by an aliphatic cyclic site (alicyclic organic group). To improve.

[0011]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies while paying attention to the above characteristics, and as a result, have found that the above object can be achieved by selecting a specific acid-decomposable group. Based on the above, the present invention has been achieved. (1) A positive photoresist composition comprising a polymer having a structure represented by the following general formula (I) as a repeating unit, and a compound which is decomposed by irradiation with actinic rays or radiation to generate an acid. .

Formula (I)

Embedded image

Here, R ₁ represents a hydrogen atom or an alkyl group. (2) A copolymer containing, as a repeating unit, the structure represented by the general formula (I) described in the above (1) and the structure represented by the following general formula (II), and decomposes by irradiation with actinic rays or radiation. A positive photoresist composition comprising a compound that generates an acid by heating.

Formula (II)

Embedded image

Here, R ₂ represents a monovalent aliphatic cyclic hydrocarbon group. (3) A copolymer containing the structure represented by the general formula (I) described in the above (1) and the structure represented by the following general formula (III) as repeating units, and decomposed by irradiation with actinic rays or radiation. A positive photoresist composition comprising a compound that generates an acid by heating.

General formula (III)

Embedded image

R ₃ ; a linking group containing a divalent aliphatic cyclic hydrocarbon group X; —COOH, —OH, —COOR ₇ , or —OR ₇ R ₇ ; a tertiary alkyl group, tetrahydropyranyl Group, tetrahydrofuranyl group, alkoxymethyl group or alkoxyethyl group. (4) The compound of the above (1) to (1), wherein the compound which decomposes upon irradiation with actinic rays or radiation to generate an acid is an N-hydroxymaleimide sulphonate compound represented by the following general formula (IV): The positive photoresist composition according to any of (3).

General formula (IV)

Embedded image

Here, R ₄ and R ₅ 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 ₄ and R ₅ are linked via an alkylene group). R ₆ may represent an alkyl group, a perfluoroalkyl group, or a cycloalkyl group. (5) The positive photoresist composition as described in any one of (1) to (4) above, wherein the exposure wavelength is far ultraviolet rays of 170 nm to 220 nm.

As the acid-decomposable group, the above-mentioned acid-decomposable groups have been typically proposed. For example, in the case of a t-butyl ester group, the acid-decomposability is extremely poor, so that the sensitivity is lowered. On the contrary, in the case of a tetrahydropyranyl ester group, on the contrary, the stability is poor, and in the case of a 3-oxocyclohexyl ester group, the above viewpoint is insufficient. That is, the object of the present invention has been achieved for the first time by selecting a 2-oxocyclohexyl ester group as a protecting group (acid-decomposable group) for an alkali-soluble group that is decomposed by the action of an acid. This is a surprising and surprising result, which is unexpected from the previous findings, and although the details are unknown, it is thought that this was achieved by skillfully selecting the position of the carbonyl group.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The alkyl group of R ₁ in the above formula (I) is preferably a methyl group or an ethyl group, particularly preferably a methyl group. Examples of the monovalent aliphatic cyclic hydrocarbon group for R ₂ 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 hydrocarbon group of the linking group containing a divalent aliphatic cyclic hydrocarbon group represented by R ₃ include the following partial structures.

[0022]

Embedded image

The linking group in R ₃ connecting the aliphatic cyclic hydrocarbon group to the ester residue and the X group includes a single bond, an alkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a sulfone group. 2 such as an amide group
And a valent organic linking group. However, one or two or more linking groups can be used in combination. R ₇ is selected from the group consisting of 3 groups such as t-butyl group and t-amyl group.
Grade alkyl group, tetrahydropyranyl group, tetrahydrofuranyl group, alkoxymethyl group, -CH (CH ₃₎ O
_{CH 2 CH 3, -CH (CH} 3) OCH 2 CH (C
H ₃₎ include alkoxyethyl group ₂ or the like.

In the present invention, a polymer containing, as a repeating unit, a monomer having a 2-oxocyclohexyl ester group as a protective group (acid-decomposable group) for an alkali-soluble group which is decomposed by the action of an acid, is preferably 2-oxocyclohexyl. The amount of the repeating unit of the monomer having an ester group in the molecule is preferably from 5 mol% to 80 mol%, more preferably from 10 mol% to 70 mol%. When the amount of the repeating unit of the monomer having a 2-oxocyclohexyl ester group in the molecule is less than 5 mol%, the effects of the present invention, that is, the adhesion of the unexposed portion to the substrate and the residual film property are deteriorated, On the other hand, when it exceeds 80 mol%, deterioration of dry etching resistance is observed.

On the other hand, a monomer containing an aliphatic cyclic hydrocarbon group, which is a copolymer monomer for imparting dry etching resistance (a monomer of the general formula (II) or (III) Is preferably from 95 mol% to 20 mol%, more preferably from 90 mol% to 30 mol%.

In addition to the above monomers, the following monomers can be copolymerized as repeating units.
It is not limited to these. Thereby, the performance required for the resin, in particular, (1) solubility in a coating solvent, (2) film forming property (glass transition point), (5) alkali developability, film slippage (hydrophobicity, 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 copolymerized monomers. For example, it is a compound having one addition-polymerizable unsaturated bond selected from acrylates, acrylamides, methacrylates, 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 having a 2-oxocyclohexyl ester group in the molecule and the monomer having an aliphatic cyclic site. Is preferably 90 mol% or less, and more preferably 80 mol% or less. When it exceeds 99 mol%, the effect of the present invention is not exhibited.

Specific examples of such other monomers include 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, wherein the alkyl group has 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-alkyl methacrylamide (where the alkyl group has 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), (II) or (III) may be used.

Preferred examples of the copolymer in the present invention include compounds represented by the following general formula (V), but are not limited thereto.

[0037]

Embedded image

Here, R _{1 to} R ₃ , R ₇ and X are the same as above. R _8; methyl, ethyl, propyl, isopropyl, n- butyl group a; 0~95 b; 0~95 c; 5~80 d; 0~50 e; 0~50 f; 0~30 a + b + c + d + e + f = 100 a + b ≧ 50 b + c + d ≧ 30. The weight average molecular weight of the copolymer in the present invention,
2,000-200,000 is preferred. If the weight average molecular weight is less than 2,000, heat resistance and dry etching resistance are deteriorated, which is not preferable. If the weight average molecular weight is more than 200,000, developability is deteriorated and viscosity becomes extremely high, so that film formability is deteriorated. Not preferred.

In the present invention, the amount of the polymer containing a repeating unit having the structure represented by the general formula (I) as a protecting group for an alkali-soluble group which is decomposed by the action of an acid in a composition is based on the total solid content. 40 to 99% by weight, preferably 50 to 97% by weight. The copolymer of the present invention,
It can be synthesized by a usual method such as radical polymerization using an azo compound or the like as an initiator.

In the present invention, a polymer (acid-decomposable group) containing, as a repeating unit, a monomer having a 2-oxocyclohexyl ester group in the molecule as a protective group (acid-decomposable group) for an alkali-soluble group decomposed by the action of an acid. The resin having a group in the molecule) forms a positive photoresist in combination with a compound (photoacid generator) that decomposes upon irradiation with actinic rays or radiation to generate an acid.

Next, the photoacid generator will be described. The necessary conditions for the photoacid generator are (1) transparency to exposure light (provided that there is no photobleaching property), and (2) sufficient photodegradability to ensure resist sensitivity. These two requirements are conflicting performance. 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, JP-A-7-25846
JP, JP-A-7-28237, JP-A-7-92
675, and JP-A-8-27102.
Alkyl sulfonium salts having an oxocyclohexyl group, and N-hydroxysuccinimide sulfonates, and also J. Photopolym. Sci. Technol.,
Vol 7, No3, p 423 (1994) and the like, and a sulfonium salt represented by the following general formula (VI);
Disulfones represented by II) and compounds represented by the following general formula (VIII) can be mentioned.

[0042]

Embedded image

Here, R _{10 to} R ₁₃ may be the same or different and represent an alkyl group or a cyclic alkyl group.

Further, N-hydroxymaleimide sulphonates are also suitable. Among the above N-hydroxymaleimide sulphonates, the compound represented by the above general formula (IV) is preferable. In the general formula (IV), R ₄ and R ₅ 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 ₄ and R ₅ are alkylene groups. And may form a ring by bonding through). R ₆ represents an alkyl group, a perfluoroalkyl group, or a cycloalkyl group. R ₄ and R ₅ in the general formula (I) have 1 to 1 carbon atoms.
As the six alkyl groups, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl,
Examples thereof include a tert-butyl group, an n-pentyl group, and an n-hexyl group. Among them, preferred is a methyl group,
An ethyl group and a propyl group are preferred, and a methyl group and an ethyl group are more preferred. Examples of the cycloalkyl group 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 ₄ and R ₅ 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 ₆ 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 cycloalkyl 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 general formula (IV) below
Specific examples of the compound represented by are shown below, but the content of the present invention is not limited thereto.

[0046]

Embedded image

[0047]

Embedded image

The compound represented by the general formula (IV) is GFJa
ubert, Ber., 28, 360 (1895), DEAmes et al., J. Chem. Soc., 3518 (1955), or MASt
olberg et al., J. Am. Chem. Soc., 79.2615 (1957), and the N-hydroxyimide compound synthesized according to the method and the like and sulfonic acid chloride under basic conditions, for example, L. Bauer et al., J. Org. Chem., 24. 1294. (1959).

Among the above-mentioned photoacid generators, N-hydroxymaleimide sulfonates represented by the general formula (IV) are preferable. The additive of the photoacid generator 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. 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), 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., Solid State Sci.Techno
l., 130 (6), FMHoulihan et al., Macromolcules, 21, 2001
(1988), European Patent Nos. 0290,750, 046,083, 156,5
Nos. 35, 271,851, 0,388,343, U.S. Pat.
No. 1,710, 4,181,531, JP-A-60-198538, JP-A-53-133022, etc., a photoacid generator having an o-nitrobenzyl-type protecting group, M.TUNOOKAetal, 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
, H. Adachi et al, Polymer Preprints, Japan, 37 (3), European Patent Nos. 0199,672, 84515, 199,672, 04
No. 4,115, No. 0101,122, U.S. Pat.
Nos. 371,605, 4,431,774, JP-A-64-18143, JP-A-2-245756, Japanese Patent Application No. 3-140109, and the like, which generate sulfonic acid upon photolysis represented by iminosulfonate and the like. And disulfone compounds described in JP-A-61-166544 and the like.

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 will be 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).

[0054]

Embedded image

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.

[0056]

Embedded image

[0057]

Embedded image

[0058]

Embedded image

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

[0060]

Embedded image

In the formula, Ar ¹ and Ar ² each independently represent a substituted or unsubstituted aryl group. Here, 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,
And mercapto groups and halogen atoms.

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. .

[0063] 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.

[0066]

Embedded image

[0067]

Embedded image

[0068]

Embedded image

[0069]

Embedded image

[0070]

Embedded image

[0071]

Embedded image

[0072]

Embedded image

[0073]

Embedded image

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

[0076]

Embedded image

Where Ar^Three, Ar^FourAre each independently substituted
Or an unsubstituted aryl group. R ²⁰⁶Is replaced or
Indicates an unsubstituted alkyl group or aryl group. A is a substitution
Or unsubstituted alkylene, alkenylene, arylene
Shows a substituent group. Specific examples include the compounds shown below.
However, the present invention is not limited to these.

[0078]

Embedded image

[0079]

Embedded image

[0080]

Embedded image

[0081]

Embedded image

[0082]

Embedded image

The photoresist composition of the present invention may be used for the purpose of improving the alkali solubility of the system or adjusting the glass transition temperature of the system to prevent the film from becoming brittle or from deteriorating the heat resistance. A suitable 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 —N
Compounds containing an acidic group in the molecule such as H-SO _2- ) compounds can be mentioned. The content of the alkali-soluble low-molecular compound is preferably 40% by weight or less, more preferably 30% by weight or less, based on the resin having a substituent which increases the solubility in an alkali developing solution with the acid. More preferably, it is at most 25% by weight.

As the solvent used in the present invention, a component composed of a polymer compound and a photoacid generator is sufficiently dissolved, and the solution can form a uniform coating film by a method such as spin coating. Any organic solvent may be used. 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, methyl 3-methoxypropionate , 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, Examples include diethylene glycol dimethyl ether, but are not limited thereto.

The “basic” components of the photoresist composition of the present invention are the above-mentioned photoacid generator, resin containing an acid-decomposable group, and a solvent (optionally, an alkali-soluble low-molecular compound). If necessary, other components such as a surfactant, a dye, a stabilizer, a coating improver, and a dye may be added.

Further, when a fine pattern is formed by using the present invention, a developer suitable for the solubility of the polymer compound used in the present invention, a mixed solvent thereof, or a suitable solvent 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 photoresist composition of the present invention is applied on a substrate to form a thin film. The thickness of this coating is 0.4 to
1.5 μm is preferred. In the present invention, as the exposure means, one having an exposure wavelength in the range of 170 to 220 nm, such as ArF excimer laser stepper exposure, is preferable. Particularly preferred is an ArF excimer laser stepper.

[0088]

EXAMPLES Hereinafter, the present invention will be described by way of examples with reference to examples, but the content of the present invention is not limited to these examples. (1) Synthesis of Resin A Isoboronyl methacrylate 18 g 2-oxocyclohexyl methacrylate 10 g Methacrylic acid 2 g THF 70 g was dissolved, and the reaction solution was cooled to 65 while flowing nitrogen for 30 minutes.
Heated to ° C. As a polymerization initiator, 100 mg of V-65 (a product of Wako Pure Chemical Industries, Ltd.) was added in four divided portions every two hours. After adding the final initiator, it was heated for 4 hours. After the heating was completed, the reaction solution was returned to room temperature, and THF 10
0 g 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 450 in terms of standard polyethylene.
00.

(2) Synthesis of Resin B A monomer [I] having the following structure was synthesized according to the method described in JP-A-8-12626.

[0090]

Embedded image

After dissolving 24 g of the monomer [I], 14 g of 2-oxocyclohexyl methacrylate, 2 g of methacrylic acid and 95 g of THF, the reaction solution was cooled to 65 while flowing nitrogen for 30 minutes.
Heated to ° C. As a polymerization initiator, 120 mg of V-65 (a product of Wako Pure Chemical Industries, Ltd.) was added in four divided portions every two hours. After adding the final initiator, it was heated for 4 hours. After the heating was completed, the reaction solution was returned to room temperature, and THF 10
0 g 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 550 in terms of standard polystyrene.
00.

(3) Synthesis of Comparative Resin C Isobornyl methacrylate 18 g 3-oxocyclohexyl methacrylate 10 g Methacrylic acid 2 g THF 70 g was dissolved, and then the reaction solution was cooled to 65 while flowing nitrogen for 30 minutes.
Heated to ° C. As a polymerization initiator, 100 mg of V-65 (a product of Wako Pure Chemical Industries, Ltd.) was added in four divided portions every two hours. After adding the final initiator, it was heated for 4 hours. After the heating was completed, the reaction solution was returned to room temperature, and THF 10
0 g 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 440 in terms of standard polystyrene.
00.

(4) Synthesis of Comparative Resin D Isoboronyl methacrylate 18 g Tetrahydropyranyl methacrylate 9 g Methacrylic acid 2 g THF 70 g was dissolved, and the reaction solution was cooled to 65 while flowing nitrogen for 30 minutes.
Heated to ° C. As a polymerization initiator, 100 mg of V-65 (a product of Wako Pure Chemical Industries, Ltd.) was added in four divided portions every two hours. After adding the final initiator, it was heated for 4 hours. After the heating was completed, the reaction solution was returned to room temperature, and THF 10
0 g 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 430 in terms of standard polystyrene.
00.

(5) Synthesis of Comparative Resin E Isobornyl methacrylate 18 g t-butyl methacrylate 7 g methacrylic acid 2 g THF 65 g was dissolved, and the reaction solution was cooled to 65 while flowing nitrogen for 30 minutes.
Heated to ° C. As a polymerization initiator, 100 mg of V-65 (a product of Wako Pure Chemical Industries, Ltd.) was added in four divided portions every two hours. After adding the final initiator, it was heated for 4 hours. After the heating was completed, the reaction solution was returned to room temperature, and THF 10
0 g 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 450 in terms of standard polystyrene.
00.

(6) 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 0 ° C. for 3 hours. After completion of the reaction, aqueous hydrochloric acid was added, the mixture was further saturated with sodium chloride, and 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 dropwise over 1 hour while cooling with ice. Furthermore,
After 2.8 g of topidine was added dropwise over 2 hours, the ice bath was removed, and the mixture was heated to room temperature and 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.

[0096]

Embedded image

(7) Preparation and Evaluation of Positive Photoresist Composition After dissolving 1.2 g of resins A to E and 0.1 g of photoacid generator synthesized in the above synthesis example in (PGMEA) to a solid content of 14%. And filtered through a 0.1 μm microfilter to prepare a positive photoresist composition. The obtained resist solution is applied on a silicon wafer using a spin coater, dried at 110 ° C. for 90 seconds, a resist film of about 0.5 μm is formed, and exposed with ArF excimer laser (wavelength 193n).
m) was performed. After a heat treatment after exposure at 110 ° 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. [Evaluation] The sensitivity was defined as the exposure amount that reproduced a line width of 0.35 μm, and the relative sensitivity was defined as 1 (the sensitivity in Example 2 and the sensitivity in Example 1) with the resist sensitivity in Example 1 as 1. Scanning electron microscope (S)
(EM) to evaluate the bite at the substrate interface. × indicates that biting was observed, and ○ indicates that no biting was observed.
And Further, the film thickness of the unexposed portion after development was measured, the change in the film thickness before exposure and after the development was measured, and the amount of film loss was evaluated as a change rate divided by the film thickness before exposure.

[0098]

[Table 1]

As described above, the resin (copolymer) of the comparative example
Has problems with sensitivity, film loss, or adhesion,
The present invention is all good, and is suitable for lithography using far ultraviolet rays such as ArF excimer laser exposure.

[0100]

The positive photoresist composition of the present invention is suitable for exposure to far ultraviolet rays, has high sensitivity, is excellent in the amount of film loss in the unexposed area, and has excellent substrate adhesion.
It is suitable as a material for lithography using light of 20 nm.

Claims (5)

[Claims] 1. A positive photoresist comprising a polymer having a structure represented by the following general formula (I) as a repeating unit and a compound capable of decomposing upon irradiation with actinic rays or radiation to generate an acid. Composition. General formula (I) Here, R ₁ represents a hydrogen atom or an alkyl group. 2. A copolymer comprising a structure represented by the general formula (I) according to claim 1 and a structure represented by the following general formula (II) as repeating units, and decomposed by irradiation with actinic rays or radiation. A positive photoresist composition comprising a compound capable of generating an acid. General formula (II) Here, R ₂ represents a monovalent aliphatic cyclic hydrocarbon group. 3. A copolymer comprising a structure represented by the general formula (I) according to claim 1 and a structure represented by the following general formula (III) as repeating units, and decomposed by irradiation with actinic rays or radiation. A positive photoresist composition comprising a compound capable of generating an acid. General formula (III) Here, R ₃ ; a linking group containing a divalent aliphatic cyclic hydrocarbon group X; —COOH, —OH, —COOR ₇ , or —OR ₇ R ₇ ; tertiary alkyl group, tetrahydropyranyl group, tetrahydrofuran Represents a nyl group, an alkoxymethyl group or an alkoxyethyl group. 4. The compound which decomposes upon irradiation with actinic rays or radiation to generate an acid is an N-hydroxymaleimide sulphonate compound represented by the following general formula (IV). 4. The positive photoresist composition according to any one of items 1 to 3, General formula (IV) Here, R ₄ and R ₅ 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 ₄ and R ₅ are bonded via an alkylene group. R ₆ may represent an alkyl group, a perfluoroalkyl group, or a cycloalkyl group. 5. The exposure wavelength is 170 nm to 220 nm.
The positive photoresist composition according to claim 1, wherein the composition is a far ultraviolet ray.