JPH08272086A - Radiation sensitive coating composition - Google Patents

Abstract

PURPOSE: To provide a radiation sensitive coating compsn. having satisfactory coating property, hardly generating bubbles at the time of exposure and having satisfactory heat resistance. CONSTITUTION: In the radiation sensitive coating compsn. contg. a base resin, a radiation sensitive compd. and a solvent, a solvent contg. a compd. represented by the formula is used as the solvent In the formula, each of R<1> -R<3> is optionally halogen substd. methyl or ethyl and R<4> is H, optionally halogen substd. methyl or ethyl.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a radiation-sensitive coating composition which is sensitive to radiation, and more particularly to improvement of a radiation-sensitive coating composition comprising a base resin, a radiation-sensitive compound and a solvent. is there.

[0002]

2. Description of the Related Art Integrated circuits have been highly integrated over the years, and dynamic random access memory (DRA)
Taking M) as an example, at present, full-scale production of a device having a storage capacity of 4 Mbits has started. Along with this, demands for photolithography technology, which is indispensable for the production of integrated circuits, are becoming stricter year by year. For example, in the production of 1M bit DRAM, 1 μm level lithography technology is required, and in 4M and 16MDRAM,
It is said that lithography techniques of 0.8 μm level and 0.5 μm level are required respectively.

In order to meet this requirement, a high-performance radiation-sensitive coating composition has been earnestly developed, but from the process side of use, in addition to performance such as high resolution, sensitivity and coating film thickness are essential. There is a demand for a high-performance composition from various viewpoints such as the uniformity, the adhesion to a substrate, the heat resistance, and the storage stability of the composition. On the other hand, the problem of safety has been pointed out in recent years for ethyl cellosolve acetate, which is a solvent used in radiation-sensitive coating compositions, and a solvent that can replace it has been demanded.

That is, it is said that ethyl cellosolve acetate produces ethoxyacetic acid in vivo and the alkoxyacetic acid exhibits toxicity (Chemical Economy, August 1988, 7).
Page 2 and European Chemical I
ndustry Ecological and Toxic
logic Center Technical Re
port No. 4 July 30, 1982, and No. 4 of the same. 17 April 19, 1985).

As a solvent that replaces ethyl cellosolve acetate, for example, propylene glycol alkyl ethers such as propylene glycol methyl ether are disclosed in JP-A-61-1648, and propylene glycol is disclosed in JP-A-61-7837. Propylene glycol alkyl ether acetates such as methyl ether acetate are disclosed in JP-A-62-123444, and methyl methoxyacetate, ethyl ethoxyacetate, and 2-oxy-2.
Monooxymonocarboxylic acid esters such as methyl-methylpropionate (same as methyl 2-hydroxy-2-methylpropionate), ethyl 2-oxypropionate and ethyl 3-methoxypropionate have been proposed as solvents.

On the other hand, in the United States, ethyl lactate (ethyl 2-oxypropionate), ethyl 3-ethoxypropionate and the like are used as safe solvents (SEMICOND).
UCTOR INTERNATIONAL April 1988 page 132). However, although ethyl 2-oxypropionate has been evaluated as a highly safe solvent in recent years, the viscosity of the radiation-sensitive coating composition has become high, and it has recently been used for manufacturing LSIs such as 8 inches. In the case of a caliber wafer, the problem that the coating uniformity in the wafer surface is deteriorated and the industrial value is reduced has been raised.
In order to improve it, a mixed solvent with propylene glycol methyl ether acetate, butyl acetate, ethyl 3-ethoxypropionate, etc. has been proposed (JP-A-6-
51506, JP-A-6-214383, and JP-A-6-273929).

Regarding the coating uniformity within the wafer surface, a phenomenon called striation that can be visually observed occurs in a severe case. Striation refers to a phenomenon in which a striped pattern appears radially from the center of the wafer, and thin coating areas and thick coating layers are alternately distributed in these radial stripes. Usually, a surfactant is added as a coatability improving agent to improve striation, but it cannot be improved depending on the type of the solvent, and therefore a solvent that hardly causes striation is required. Further, there is a demand for a solvent that can be applied and coated satisfactorily on the entire surface of a wafer with a small amount of dropping.

On the other hand, the foaming phenomenon at the time of exposure has become a problem in recent high-performance radiation-sensitive coating compositions. The bubbling phenomenon means that there are no air bubbles in the film when the radiation-sensitive coating composition is applied to the wafer, but the nitrogen gas etc. generated by the decomposition of the quinonediazide group and the like is rapidly diffused out of the film by exposure. A phenomenon in which bubbles are generated in a film without being treated. If the generated bubbles are large, the part that should originally remain after development becomes a scooped transfer pattern shape, and if the foaming is more severe, bubbles are generated at the interface between the coating film and the substrate, and the coating film rises. This causes a problem that a pattern that should remain after development is peeled off and disappears.

The generated bubbles can be confirmed by observing them with an optical microscope, or the number of bubbles can be measured by a laser surface inspection device for measuring particles on the wafer. In particular, recent high-performance radiation-sensitive coating compositions contain a large amount of radiation-sensitive compounds containing a quinonediazide group or the like, and relatively easily cause a foaming phenomenon (a large amount of nitrogen gas is easily generated). It is a composition, and improvement is desired.

Further, it is desirable that the generated pattern has high heat resistance. However, even if the materials such as resin are exactly the same, different solvents give different heat resistance, and a solvent giving high heat resistance is desired. Heat resistance is affected by the amount of solvent remaining in the film,
In general, a solvent having a low boiling point has a higher evaporation rate, and it is presumed that the amount of the remaining solvent is small, which is preferable, but in the radiation-sensitive coating composition, the evaporation rate of the solvent and the boiling point of the solvent are different from each other. Since there is no correlation, and it is difficult to know unless the composition is actually adjusted and tested and measured, it is difficult to estimate from the physical properties (Ultra Clean Resist Processing P.43-, June 28, 1990).

[0011]

In view of the background described above, the object of the present invention is that the coating property and the like in a solvent replacing ethyl cellosolve acetate, ethyl lactate or the like is equal to or higher than the conventional one, and the foaming phenomenon is small. It is to provide a radiation-sensitive coating composition having good heat resistance and the like.

[0012]

Means for Solving the Problems As a result of studies to achieve such an object, the present inventors have found that among the monooxymonocarboxylic acid esters, a special solvent which has not been known as a solvent for a radiation-sensitive coating composition has hitherto been known. It was found that only a solvent containing a compound having the structural formula of (5) selectively exerts a peculiar effect and is optimal as a solvent for a radiation-sensitive coating composition. That is, the gist of the present invention is that in a radiation-sensitive coating composition containing a base resin, a radiation-sensitive compound, and a solvent, a solvent containing a compound represented by the following general formula (I) is used. And a radiation-sensitive coating composition.

[0013]

Embedded image

(In the formula, R ¹ , R ² and R ³ represent a methyl group which may be substituted with a halogen atom or an ethyl group, which may be the same or different from each other. R ⁴ is a hydrogen atom. , A methyl group which may be substituted with a halogen atom,
Alternatively, it represents an ethyl group. )

The present invention will be described in detail below. The base resin used in the present invention is generally an alkali-soluble resin, and more specifically, (1) a novolac resin,
(2) Polyhydroxystyrene or its derivative, styrene-maleic anhydride copolymer, vinyl polymer such as vinyl polymer having phenolic hydroxyl group or sulfonamide group, (3) Carboxyl group, sulfonamide group Examples of the urethane resin include novolac resin, polyhydroxystyrene and derivatives thereof.

Novolak resins include phenol, o
-Cresol, m-cresol, p-cresol, 3-
Phenols which may be substituted with an alkyl group or an aryl group such as ethylphenol, 2,5-xylenol, 3,5-xylenol, phenylphenol; 2-methoxyphenol, 4-methoxyphenol, 4-phenoxyphenol and the like. Alkoxy or aryloxyphenols; naphthols which may be substituted with an alkyl group such as α-naphthol, β-naphthol, 3-methyl-α-naphthol; 1,3-dihydroxybenzene,
1,3-dihydroxy-2-methylbenzene, 1,2,
Hydroxy aromatic compounds such as polyhydroxybenzenes which may be substituted with alkyl groups such as 3-trihydroxybenzene, 1,2,3-trihydroxy-5-methylbenzene and 1,3,5-trihydroxybenzene And aliphatic aldehydes such as formaldehyde, paraformaldehyde and acetaldehyde, aromatic aldehydes such as benzaldehyde and hydroxybenzaldehyde, and carbonyl compounds such as alkyl ketones such as acetone,
For example, those produced by heating and polycondensing in the presence of an acidic catalyst such as hydrochloric acid, sulfuric acid, oxalic acid and the like can be mentioned.

The hydroxyaromatic compound may have a substituent such as a halogen atom, a nitro group or an ester group as long as it does not adversely affect the present invention. If desired, these resins may be further reduced with hydrogen or the like to reduce absorption in the short wavelength region. Examples of polyhydroxystyrene or its derivative include 4
Polymers such as -hydroxystyrene, 3-methyl-4-hydroxystyrene, and 3-chloro-4-hydroxystyrene are mentioned. If necessary, these resins may
It is also possible to use those which have been reduced by hydrogen or the like to reduce the absorption in the short wavelength region, and a substituent such as a halogen atom, a nitro group or an ester group may be added to the aromatic compound monomer unless it adversely affects the present invention. You may have. Further, the phenolic hydroxyl group may be used by substituting it with an esterified product such as t-butyloxycarbonyl group. The vinyl polymer having a phenolic hydroxyl group or a sulfonamide group is a polymer formed by the cleavage of a carbon-carbon double bond and is at least one of the following general formulas [II] to [VIII]. Polymers containing structural units are preferably used.

[0018]

Embedded image

[0019]

[Chemical 4]

In the formula, R ⁵ and R ⁶ each represent a hydrogen atom, an alkyl group or a carboxyl group, preferably a hydrogen atom. R ⁷ represents a hydrogen atom, a halogen atom or an alkyl group, preferably a hydrogen atom or an alkyl group such as a methyl group or an ethyl group. R ⁸ represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and preferably a hydrogen atom. A represents an alkylene group which may have a substituent connecting a nitrogen atom or an oxygen atom and an aromatic carbon atom, m represents an integer of 0 to 10,
B represents a phenylene group which may have a substituent or a naphthylene group which may have a substituent. Of these, a copolymer containing at least one structural unit represented by the general formula [VIII] is preferable.

The vinyl-based polymer preferably has a copolymer type structure, and in such a copolymer, the structural unit represented by each of the general formulas [II] to [VIII] is Examples of the monomer unit that can be used in combination with at least one kind include ethylenically unsaturated olefins such as ethylene, propylene, isobutylene, butadiene, and isoprene, for example, styrene, α-methylstyrene, p-methylstyrene, p Styrenes such as chlorostyrene, acrylic acids such as acrylic acid and methacrylic acid, unsaturated aliphatic dicarboxylic acids such as itaconic acid, maleic acid and maleic anhydride, such as methyl acrylate, ethyl acrylate, acrylic acid n -Butyl, isobutyl acrylate, dodecyl acrylate, 2-chloroethane acrylate , Phenyl acrylate, α-methyl chloroacrylate, methyl methacrylate, ethyl methacrylate, ethyl ethacrylic acid and other α-methylene aliphatic monocarboxylic acid esters such as acrylonitrile, methacrylonitrile and other nitriles such as acrylamide. Amides such as acrylic anilide, p
-Chloroacrylanilide, m-nitroacrylanilide, m-methoxyacrylanilide, and other anilides, such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, and other vinyl esters, such as methyl vinyl ether, ethyl vinyl ether, and isobutyl vinyl ether. , Vinyl ethers such as β-chloroethyl vinyl ether, vinyl chloride, vinylidene chloride, vinylidene cyanide, for example, 1-methyl-1-methoxyethylene, 1,1-dimethoxyethylene, 1,2-dimethoxyethylene, 1,1-dimethoxy. Carbonyl ethylene, ethylene derivatives such as 1-methyl-1-nitroethylene, such as N-vinylpyrrole, N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidene,
There are vinyl monomers such as N-vinyl compounds such as N-vinylpyrrolidone. These vinyl-based monomers have a structure in which unsaturated double bonds are cleaved and are present in the polymer compound.

Among the above monomers, the general formulas [II] to [XI
As the one used in combination with at least one structural unit represented by II], (meth) acrylic acid, esters of aliphatic monocarboxylic acid, and nitriles show comprehensively excellent performance and are preferable. More preferred are methacrylic acid, methyl methacrylate, acrylonitrile, ethyl acrylate and the like. These monomers may be bonded to the vinyl polymer in either a block or random state.

The optimum weight average molecular weight of the base resin is usually 2,000 to 30,000, preferably 3,000.
~ 20,000. Further, in view of the performance of the radiation-sensitive coating composition, a resin excluding a low molecular weight component or a resin in which two or more kinds of resins having different molecular weights are mixed (the molecular weight distribution is widened) may be used. It is also possible to use a base resin from which the low molecular weight components in the above resin have been removed by a technique such as fractional crystallization.

The radiation-sensitive compound used in the present invention is usually a photosensitizer containing an orthoquinonediazide group, an azide compound, or a photoacid generator containing a polyhalogenated hydrocarbon group, a photocrosslinking compound, a photopolymerization compound, A diazo compound etc. can be mentioned. Examples of the photosensitizer containing an orthoquinonediazide group include 1,2-benzoquinonediazide-4-sulfonic acid and 1,2-naphthoquinonediazide-4.
-Orthoquinonediazide-based photosensitizers such as esters or amides of sulfonic acid, 1,2-naphthoquinonediazide-5-sulfonic acid, and specifically, polyhydroxyalkyl compounds such as glycerin and pentaerythritol, novolac resins, bisphenol A , 4,4 ', 4 "
-Trihydroxyphenylmethane, gallic acid ester,
Polyhydroxy aromatic compounds such as quercetin, morin and polyhydroxybenzophenone, 1,2-benzoquinonediazide-4-sulfonic acid, 1,2-naphthoquinonediazide-4-sulfonic acid, 1,2-naphthoquinonediazide-5-sulfonic acid And the like are preferably used. Of these, esterified products of phenolic hydroxyl group-containing compounds are preferable, and esterified products of polyhydroxybenzophenone or novolac resin are particularly preferable. Further, a sensitizer containing two or more, preferably three or more orthoquinonediazide groups in one molecule is preferable.

Examples of the azide compound include 4,4 '
-Diazidostilbene, p-phenylenebisazide,
4,4'-diazidobenzophenone, 4,4'-diazidochalcone, 4,4'-diazidodiphenyl, 4,4 '
-Diazidodiphenylmethane, 4,4'-diazide-
3,3'-dimethyldiphenyl, 2,7-diazidofluorene, 4,4'-diazidodibenzyl, 4,4'-diazidophenyl ether, 3,3'-dichloro-4,
4'-diazidodiphenylmethane, 3,3'-diazidophenyl sulfone, 4,4'-diazidophenyl sulfone, 4,4'-diazidophenyl sulfide, 4,4 '
-Diazidophenyl disulfide, 2,6-bis (4 '
-Azidobenzal) cyclohexanone, 2,6-bis (4'-azidobenzal) -4-methylcyclohexanone and the like.

The photoacid generator containing a polyhalogenated hydrocarbon group is usually hexachloroethane, hexachloroacetone, 1,2,3,4,5,6-hexachlorocyclohexane, carbon tetrabromide, iodoform, 1, 1, 2,
Examples thereof include a photoacid generator containing a polyhalogenated hydrocarbon group such as 2-tetrabromoethane. These polyhalogenated hydrocarbon groups are, for example, tris (trichloromethyl) -s-triazine, bis (tribromomethyl) benzene, tribromomethylphenyl sulfone, etc.
It may be contained as a substituent such as triazine or benzene or as a constituent group of a sulfone compound. or,
An iodonium salt such as diphenyl iodonium hexafluorophosphonate and diphenyl iodonium chloride, and an onium salt such as triphenyl sulfonium hexafluorophosphonate and sulfonium salt such as triphenyl sulfonium bromide can also be used as the photoacid generator.

Also, if necessary, it acts under acidic conditions,
It is also possible to add a crosslinking agent for the alkali-soluble resin.
Specific examples of this crosslinking agent include hexamethoxymethylated melamine, N, N, N ', N'-tetrahydroxymethylsuccinamide, tetramethoxymethylated urea, 2,4,4.
Examples thereof include compounds having two or more crosslinker groups such as hydroxymethyl group such as 6-trihydroxymethylated phenol, methoxymethyl group and ethoxymethyl group in one molecule.

Examples of the photocrosslinkable compound include those mainly composed of a photosensitive resin having an unsaturated double bond in the molecule. Examples of the resin include US Pat. No. 3,030,
No. 208, No. 3,453,237 and No. 3,6
As described in No. 22,320, a photosensitive resin containing a photosensitive group —CH═CH—CO— in a polymer main chain and polyvinyl cinnamate having a photosensitive group in a side chain of a polymer are disclosed. is there.

Examples of the photopolymerizable compound include those composed of a monomer having a double bond and a binder (polymer compound). A typical composition is US Pat. No. 2,760,8.
63, No. 2,791,504 and No. 3,80.
No. 1,328. The diazo compound is preferably a diazo resin represented by a condensate of an aromatic diazonium salt and formaldehyde, particularly preferably a salt of a condensate of p-diazodiphenylamine and formaldehyde or acetaldehyde, such as hexafluorophosphoric acid. Inorganic salt of diazo resin which is a reaction product of a salt, tetrafluoroborate, perchlorate or periodate and the above condensate, and US Pat. No. 3,300,30
Examples thereof include a diazo resin organic salt which is a reaction product of the above-mentioned condensate and sulfonic acids as described in No. 9.

Among the above radiation-sensitive compounds, the radiation-sensitive compounds containing an orthoquinonediazide group are particularly preferable.
The present invention is characterized in that among known monooxymonocarboxylic acid esters, a solvent containing the compound represented by the general formula (I) is particularly used.
In the general formula (I), examples of the halogen atom represented by R ^{1 to} R ⁴ which is a substituent of a methyl group or an ethyl group which may be substituted with a halogen atom include a chlorine atom.

Specific examples of these solvents include methyl 2-methyl-3-methoxypropionate and 2-methyl-3.
-Ethyl methoxypropionate, methyl 2-ethyl-3-methoxypropionate, ethyl 2-ethyl-3-methoxypropionate, methyl 2-methyl-3-ethoxypropionate, ethyl 2-methyl-3-ethoxypropionate, Methyl 2-ethyl-3-ethoxypropionate,
Ethyl 2-ethyl-3-ethoxypropionate, methyl 2-methyl-3-methyl-3-methoxypropionate,
Methyl 2-methyl-3-methyl-3-ethoxypropionate, methyl 2-ethyl-3-methyl-3-methoxypropionate, methyl 2-ethyl-3-methyl-3-ethoxypropionate, 2-methyl-3 -Methyl ethyl-3-methoxypropionate, 2-methyl-3-ethyl-3
-Methyl ethoxypropionate, methyl 2-ethyl-3-ethyl-3-methoxypropionate, 2-ethyl-3
-Methyl ethyl-3-ethoxypropionate, ethyl 2-methyl-3-methyl-3-methoxypropionate, 2
-Ethyl methyl-3-methyl-3-ethoxypropionate, ethyl 2-ethyl-3-methyl-3-methoxypropionate, ethyl 2-ethyl-3-methyl-3-ethoxypropionate, 2-methyl-3- Ethyl-3-methoxypropionate ethyl, 2-methyl-3-ethyl-3-
Ethyl ethoxypropionate, ethyl 2-ethyl-3-ethyl-3-methoxypropionate, 2-ethyl-3-
Ethyl ethyl-3-ethoxypropionate, methyl 2-chloromethyl-3-methoxypropionate, methyl 2-chloromethyl-3-chloromethyl-3-methoxypropionate and the like can be mentioned. Of these, compounds in which R ⁴ is a hydrogen atom are preferable, and more specifically, 2-methyl-
Methyl 3-methoxypropionate, ethyl 2-methyl-3-methoxypropionate, methyl 2-methyl-3-ethoxypropionate and ethyl 2-methyl-3-ethoxypropionate are preferable, and particularly 2-methyl-3- Methyl methoxypropionate and ethyl 2-methyl-3-ethoxypropionate are preferred.

In the present invention, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, ethyl lactate, ethyl pinbate, diethyl oxalate, γ-butyrolactone, cyclohexanone, methyl amyl ketone, It is also possible to use a solvent in which xylene or the like is mixed. In this case, the preferred mixing range is usually 60% by weight or more, preferably 70% by weight or more, and more preferably 80% by weight or more.

The concentration of the base resin in the radiation-sensitive coating composition of the present invention is usually 1 to 30% by weight, and the concentration of the radiation-sensitive compound is usually 0.01 to 15% by weight.
The ratio of the radiation sensitive compound to the base resin is usually 0.001 to 1.0 times by weight. Further, in the present invention, for example, a coating property improver for improving coating property,
A light-absorbing material may be added in order to reduce the influence of diffused light reflected from the substrate, or an additive such as a sensitizer for improving sensitivity.

Examples of the coatability improvers include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether and other polyoxyethylene alkyl ethers, polyoxyethylene octylphenol ether, polyoxyethylene nonylphenol ether and the like. Nonionic surfactants such as polyoxyethylene alkylphenol ethers and polyethylene glycol dialkyl ethers such as polyethylene glycol dilaurate and polyethylene glycol distearate, F-top EF
301, EF303, EF352 (Shin-Akita Kasei Co., Ltd.)
Manufactured by Dainippon Ink Co., Ltd., Megafac F171, F173, F179 (manufactured by Dainippon Ink and Chemicals, Inc.), and a linear fluorine-based interface having a fluorinated alkyl group or a perfluoroalkyl group exemplified in JP-A-57-178242. Activator, Florard FC430, FC431 (Sumitomo 3M Limited)
Made), Asahi Guard AG710, Surflon S-38
2, SC101, SC102, SC103, SC10
4, SC105, SC106 (manufactured by Asahi Glass Co., Ltd.) and other fluorine-based surfactants, organosiloxane polymer KP3
41 (manufactured by Shin-Etsu Chemical Co., Ltd.) or acrylic acid-based or methacrylic acid-based (co) polymer Polyflow No75, No9
5 (manufactured by Kyoeisha Oil and Fat Chemical Co., Ltd.) and the like, and one kind may be used alone or two or more kinds may be used in combination. The content of the coatability improver is usually 10 to 500 ppm with respect to the radiation-sensitive coating composition.

The coating method includes spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, curtain coating and the like. The radiation-sensitive coating composition is an image transfer method, depending on the result, a positive type,
Although classified into two types of negative type, the solvent of the present invention is basically applied to both radiation-sensitive coating compositions. The radiation-sensitive coating composition of the present invention can be applied to photoresists, PS plates, color proofs, color filters and the like, and is particularly useful as a photoresist for producing semiconductor integrated circuits.

The solvent of the radiation-sensitive coating composition of the present invention has a high dissolving ability and can well dissolve the radiation-sensitive compound which is the raw material of the radiation-sensitive coating composition. It is useful because a composition having excellent storage stability can be obtained. Since the solvent constituting the composition of the present invention has a high dissolving ability, the cleaning solvent for the line of the semiconductor manufacturing equipment such as the piping of the radiation-sensitive composition of the spin coater, the pump and the filter, and the wafer at the time of spin coating. It can also be used as a cleaning solvent for the back surface of the wafer and the edge surface of the wafer. When used as a washing solvent, it may be used alone, but within a range that does not impair the effect, ethyl acetate, butyl acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl lactate, ethyl lactate, pyruvin A solvent in which ethyl acidate, diethyl oxalate, γ-butyrolactone, cyclohexanone, methyl amyl ketone, diacetone alcohol, 1,3-dioxolane and the like are mixed may be used. In this case, at least the present solvent is used in an amount of 20% by weight or more, preferably 30% by weight or more, and more preferably 50% by weight or more.

[0037]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples without departing from the gist thereof. Unless otherwise specified, handling of radiation-sensitive composition after precision filtration is 500n.
Class 1 of the so-called Yellow Room with less than m light cut
It was carried out in a clean room of 00. The radiation-sensitive compounds and resins used in Examples, Comparative Examples and Reference Examples were as follows.

[0038]

[Table 1] Radiation-sensitive compound A: Resin obtained by polycondensing m-cresol and acetaldehyde (weight average molecular weight 10
00) 1,2-naphthoquinonediazide-5-sulfonic acid ester compound (40% esterification rate to phenolic hydroxyl group) Radiation-sensitive compound B: 2,2 ', 3,4,4'-pentahydroxybenzophenone 1,2-naphthoquinonediazide-5-sulfonate esterification product (esterification rate of 84% relative to phenolic hydroxyl group) Radiation-sensitive compound C: resin obtained by polycondensing pyrogallol and acetone (weight average molecular weight 1300) 1,2-naphthoquinonediazide-5-sulfonic acid esterified product (esterification ratio of 50% with respect to phenolic hydroxyl group) Resin A: m-cresol, p-cresol, 2,5-xylenol, formaldehyde, acetaldehyde Produced novolak resin (weight average molecular weight 3500) Resin B: m-cresol Resin, p-cresol, 2,5-xylenol, formaldehyde, novolak resin (weight average molecular weight 6000)

The abbreviations of the solvents in each table indicate the following solvents.

[0040]

[Table 2] MMMP: Methyl 2-methyl-3-methoxypropionate EL: Ethyl 2-hydroxypropionate EL / PGMEA: Ethyl 2-hydroxypropionate (70% by weight) and propylene glycol methyl ether acetate (30% by weight) ) Mixed solvent MHMP: methyl 2-hydroxy-2-methylpropionate

Example 1 and Comparative Examples 1 to 3 Radiation-sensitive compound A 18.9 g, resin A 23.1 g, each solvent 133.0 g shown in Table 1 and Megafax F-179 (large Nippon Ink Chemical Industry Co., Ltd.) was added to a concentration of 150 ppm and mixed and dissolved. This was microfiltered with a 0.2 μm Teflon filter to prepare a radiation-sensitive composition. This radiation-sensitive composition was applied to a 5-inch silicon wafer at 3000 to 5000 rpm using a spin coater manufactured by Dainippon Screen Co., Ltd., and then applied on a hot plate at 90 ° C. for 60 minutes.
Pre-baking was performed for 2 seconds to obtain a coating composition having a coating film thickness of 1.035 μm.

Bubbles in each radiation-sensitive coating film of this coating composition were measured by a laser surface inspection device (LS-5000) manufactured by Hitachi Electronics Engineering Co., Ltd. Bubbles having a particle size of 0.3 μm or more were counted. After the measurement, the wafer is used as a g-line stepper (DSW6700 manufactured by GCA).
In B), move each exposure location and move each location to Table-1.
By exposing for the time shown in Table 1, substantially the entire surface is shown in Table-1.
As shown in, the exposure time was changed and the entire surface was exposed. The number of bubbles in the coating film on each wafer after exposure was measured in the same manner as after coating. The results are shown in Table 1. The results were expressed as the difference between the measured values before and after the exposure (the number of bubbles increased by the exposure).

[0043]

[Table 3]

Example 2 and Comparative Examples 4 to 5 Radiation-sensitive compound B 7.4 g, resin B 34.6 g, Table-
133.0 g of each solvent shown in 2 and Megafac F-179 (manufactured by Dainippon Ink and Chemicals, Inc.) as a coatability improver were added in an amount of 200 ppm and mixed and dissolved. The composition was prepared and evaluated. Table 2 shows the results.

[0045]

[Table 4]

Example 3 and Comparative Examples 6 to 7 The following experiments were conducted using the radiation-sensitive compositions used in Example 1, Comparative Examples 2 and 3. Each radiation-sensitive composition was applied to a silicon wafer with a spin coater manufactured by Dainippon Screen Co., Ltd., prebaked at 80 ° C. for 90 seconds to obtain a film thickness,
A coated wafer of 1.07 μm was obtained. This wafer was exposed by a Nikon i-line stepper (NSR1755i7A), further post-exposure baked at 110 ° C. for 90 seconds, and developed with a 2.38% tetramethylammonium hydroxide aqueous solution to obtain a line width of 5 μm pattern. Was transferred onto the wafer. This wafer was heated on a hot plate at each temperature for 5 minutes, and the heat resistance was evaluated from the change in pattern shape. The results are shown in Table-3. The heat resistance was defined as the maximum temperature at which the pattern shape was not changed.

[0047]

[Table 5]

Example 4 and Comparative Example 8 Radiation-sensitive compound A 18.9 g, Resin A 23.1 g, and methyl 2-methyl-3-methoxypropionate (Example 4) or methyl methoxyacetate (Comparative Example 8) as a solvent. )
133.0 g and Megafac F as a coatability improver
-179 (manufactured by Dainippon Ink and Chemicals, Inc.) 25p
It was added so as to be pm and mixed and dissolved. A radiation-sensitive composition was prepared by microfiltration with a 0.2 μm Teflon filter. This radiation-sensitive composition was applied to a 5-inch silicon wafer at 4000 rpm using a spin coater manufactured by Dainippon Screen Co., Ltd.
Prebaking was performed at 0 ° C. for 60 seconds, and the occurrence of striation in the coating film was observed. 2-methyl-as a solvent
The one using methyl 3-methoxypropionate did not cause striation and could be applied satisfactorily, but the one using methyl methoxyacetate as a solvent caused severe striation and could not be applied satisfactorily.

Example 5, Comparative Examples 9-10 13.7 g of radiation-sensitive compound C, radiation-sensitive compound B
10.7 g, resin B 71.5 g, and as a solvent,
MMMP (Example 5), EL (Comparative Example 9) or MHMP
304 g of each solvent of (Comparative Example 10) was added, and further, Florard FC-430 (manufactured by Sumitomo 3M Limited) was added as a coatability improving agent so as to be 100 ppm, and dissolved under good stirring and mixing.

Further, it was microfiltered with a 0.2 μm Teflon filter to prepare a radiation-sensitive composition. Using a spin coater manufactured by Dainippon Screen Co., Ltd., the amount of each radiation-sensitive composition dropped onto a 5-inch silicon wafer was 1.8 m.
reduced to 1, 1000 rpm for 4 seconds, then 4000
The coating was performed by shaking off at rpm for 25 seconds. (In Examples 1 to 4 and Comparative Examples 1 to 8, the dropping amount was as large as 2 ml.)

[0051]

[Table 6]

Reference Example In Example 4, butyl acetate was used as the back rinse liquid for the back surface of the wafer, but instead of butyl acetate, methyl 2-methyl-3-methoxypropionate was used, and radiation sensitivity was the same as in Example 4. The composition was applied. Example 4
Similarly to the above, no striation was generated, and the resist was not adhered and remained on the back surface of the wafer, and the application was excellent.

[0053]

EFFECTS OF THE INVENTION According to the present invention, by using a specific solvent, the coatability is good, and foaming during exposure is unlikely to occur,
A radiation-sensitive coating composition having good heat resistance is obtained, which is extremely useful in practice.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Kawase 1-1 Kurosaki Shiroishi, Hachimansai-ku, Kitakyushu City Mitsubishi Chemical Corporation Kurosaki Development Laboratory

Claims (1)

[Claims] 1. A radiation-sensitive coating composition containing a base resin, a radiation-sensitive compound, and a solvent, wherein a solvent containing a compound represented by the following general formula is used as the solvent. Stuff. Embedded image (In the formula, R ¹ , R ² and R ³ represent a methyl group or an ethyl group which may be substituted with a halogen atom and may be the same or different from each other. R ⁴ is a hydrogen atom or a halogen atom. Represents an optionally substituted methyl group or ethyl group.)