JPH1138604A - Radiation sensitive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance resolution and sensitivity and heat resistance by using a specified base resin and a specified bissulfonyldiazomethane compound as structure components. SOLUTION: The radiation sensitive composition contains the film-forming resin and the bissulfonyldiazomethane compound to be allowed to generate an acid by exposure rerepresented by formulae I-III, and this resin comprises a copolymer of 30-90 mol.% hydroxy(methyl)styrene and 10-60 mol.% hydroxy(methyl)styrene protected with the prescribed group to be released by an acid, and it has a weight average molecular weight(Mw) of 2,000-70,000. In formulae I-III, each of R<1> and R<3> is an alkyl group; R<2> is a halogen atom or an alkoxy or nitryl or amide group or the like; each of R<4> -R<6> is an alkyl or cyano or nitryl or amide group or the like; R<7> is an alkoxy group; each of R<8> -R<10> is an II car halogen atom or an amide group or the like.

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 composition sensitive to radiation, and more particularly to a radiation-sensitive composition suitable as a resist for forming a semiconductor integrated circuit.

[0002]

2. Description of the Related Art As the degree of integration of a semiconductor integrated circuit is generally increased four times in three years as generally known, for example, dynamic random access memory (DR)
AM) as an example, full-scale production has been started at present with a storage capacity of 16 Mbits. Accordingly, the demand for photolithography technology, which is indispensable for the production of integrated circuits, has been increasing year by year. For example, the production of a 16 Mbit DRAM requires a lithography technique of 0.5 μm level, and the 64M DRAM with a higher degree of integration requires a lithography technique of 0.35 μm level. Along with this,
There is a strong need for the development of resists that can respond to each lithography level.

[0003] In today's ultra-fine process, the wavelength used for resist exposure is also the i-line (365 nm) of a mercury lamp.
From KrF excimer laser light (248 nm), and various chemically amplified positive photoresists have been proposed as positive resists suitable for such short wavelength exposure. The chemically amplified resist controls the solubility of a radiation-irradiated portion in a developing solution by a catalytic action of an acid generated by irradiation of radiation (ultraviolet rays, far-ultraviolet rays, X-rays, charged particle beams such as electron beams, etc.). It is a resist and contains a compound whose solubility in an alkali developing solution is increased by an acid catalyzed reaction with an acid generator. Problems specific to such a chemically amplified positive photoresist include a stability problem with respect to a withdrawal time between exposure and post-exposure bake (post-exposure bake),
In other words, there is a problem of fluctuation in pattern size due to diffusion of generated acid when time is left between exposure and post-exposure bake. As a technique for solving this problem, JP-A-5-249682 discloses a resist material containing a specific resin component and a specific compound as a suitable acid generator. Specifically, a resist containing polyhydroxystyrene having an ethoxyethyl group and bis (cyclohexylsulfonyl) diazomethane is disclosed.

On the other hand, in the process of fabricating a semiconductor integrated circuit, it has been conventionally required that the resist has good heat resistance. However, as a result of our investigation, the above-mentioned known resist material has a low heat resistance. Proved inadequate. If the heat resistance is inferior, the pattern is deformed in the etching process, so that the line width and the like formed on the substrate cannot be processed to desired dimensions, which causes inconvenience. In order to produce a highly integrated semiconductor integrated circuit, a high-performance radiation-sensitive coating composition has been developed energetically, but in addition to the essential high-resolution performance required by the process side used. It has been difficult to satisfy well-balanced performances such as sensitivity, heat resistance, pattern shape, and uniformity of a coating film.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a radiation-sensitive coating composition having a high resolution and capable of coping with half-micron lithography using radiation, which solves the problems of the prior art. . Another object of the present invention is to provide a radiation-sensitive coating composition having good sensitivity and heat resistance in a chemically amplified resist.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a radiation-sensitive composition comprising a film-forming resin and a bissulfonyldiazomethane compound which generates an acid upon exposure. Is a compound represented by the following general formulas (A1) to (A3),

[0007]

Embedded image

(Wherein, R ¹ and R ³ represent an optionally substituted aliphatic alkyl group, R ² represents a halogen atom,
Represents an optionally substituted alkoxy group, nitro group, cyano group, nitrile group or amide group, and represents R ⁴ , R ⁵ , R
⁶ is an alkyl group which may be independently substituted,
Represents a halogen atom, an optionally substituted alkoxy group, a nitro group, a cyano group, a nitrile group or an amide group,
R ⁷ is an optionally substituted alkoxyl group, and R ^{8 to} R
¹⁰ each independently represents a hydrogen atom, a halogen atom, an optionally substituted alkoxy group, an optionally substituted alkyl group, a nitro group, a cyano group, a nitrile group or an amide group. The following general formula (1) or (2) in which the film-forming resin is desorbed by at least 30 to 90 mol% of hydroxy (methyl) styrene with an acid.

[0009]

Embedded image

Wherein X ^{1 to} X ⁵ are independently a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms,
¹ and X ³ may combine to form a ring. X ⁶ represents an alkyl group having 1 to 10 carbon atoms. ) Containing 10 to 60 mol% of hydroxy (methyl) styrene protected by a group represented by the formula (1), and having a weight average molecular weight (Mw) of 2000 to 70
000 hydroxy (methyl) styrene copolymer.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The film-forming resin (hereinafter, referred to as a base resin) used in the present invention is generally an alkali-soluble resin, and has a function of forming a uniform radiation-sensitive layer and a function of the radiation-sensitive layer with respect to an alkali developing solution. It has the function of adjusting the solubility of the radiation-sensitive layer so that the unexposed part becomes insoluble and the exposed part becomes soluble, and further has the function of improving image reproducibility and heat resistance.

As the base resin, hydroxy (methyl) styrene and at least the above formula (1) or (2)
These are hydroxy (methyl) styrene copolymers each containing hydroxy (methyl) styrene protected by a group represented by the following formula: In the present invention, hydroxy (methyl) styrene represents hydroxystyrene or hydroxymethylstyrene.

Examples of the hydroxy (methyl) styrene include o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, o-hydroxy-α-methylstyrene, m-hydroxy-α-methylstyrene,
Examples thereof include p-hydroxy-α-methylstyrene and the like, preferably o-, m- or p-hydroxystyrene, and more preferably p-hydroxystyrene.

When X ^{1 to} X ⁵ are an alkyl group or an alkoxyl group in the protective group represented by the formula (1) or (2), the protective group preferably has 1 to 3 carbon atoms, and more preferably 1 to 5 carbon atoms. And when X ⁶ represents an alkyl group, it preferably has 1 to 6 carbon atoms, more preferably 3 to 6 carbon atoms.
5 Particularly, an ethoxyethyl group, a t-butyloxycarbonyl group, a tetrahydropyranyl group, and a tetrahydrofuranyl group are preferable.

The copolymerization ratio of hydroxy (methyl) styrene contained in the hydroxy (methyl) styrene copolymer to hydroxy (methyl) styrene protected by the group represented by formula (1) or (2) is as follows: The hydroxy (methyl) styrene is from 30 to 90, preferably 50 to 80 mol%, and the protected hydroxy (methyl) styrene is from 10 to 60, preferably 20 to 50 mol%.

If the copolymerization ratio of the hydroxy (methyl) styrene is extremely low, the radiation-sensitive layer and the exposed portion may fail to be removed (development solubility poor). If it is high, the film is likely to be reduced in the unexposed portion. Further, when the copolymerization ratio of hydroxy (methyl) styrene having a protecting group is significantly reduced,
The film thickness of the unexposed portion is reduced, and the image reproducibility is reduced. On the contrary, when the film is extremely high, the sensitivity is reduced and the omission failure is caused.

The hydroxy (methyl) styrene copolymer of the present invention may contain other copolymerizable monomers in addition to hydroxy (methyl) styrene or hydroxy (methyl) styrene having a protecting group. Examples of the copolymerized monomer include substituted styrene units described in JP-A-6-16111, JP-A-5-262699, JP-A-6-273934, etc., and JP-A-5-107761,
It may contain a (meth) acrylic acid derivative unit described in JP-A-5-210240. The copolymerization ratio of the comonomer is 0 to 50 mol%, preferably 0 to 2 mol%.
0 mol%.

Further, the benzene skeleton in the structural unit of the hydroxy (meth) styrene copolymer of the present invention is reduced to a cyclohexane skeleton by a hydrogenation reaction, whereby a deep UV light region such as an excimer beam (248 nm) can be obtained. It is possible to reduce the absorption, that is, to reduce the internal filter effect on the exposure light source. The hydroxy (meth) styrene copolymer of the present invention can polymerize each copolymerized monomer in the presence of a radical polymerization initiator, an anionic polymerization initiator or a cationic polymerization initiator. Further, after the hydroxy (methyl) styrene copolymer before the addition of the protecting group is copolymerized in advance, a part of the hydroxyl group of the hydroxy (methyl) styrene copolymer is added with an acid catalyst to add the protecting group to the desired group. A hydroxy (methyl) styrene copolymer can also be obtained.

The hydroxy (methyl) styrene copolymer has a weight average molecular weight (Mw) of 2,000 to 70,000,
It is preferably from 3,000 to 60,000, more preferably from 5,000 to 40,000. When the molecular weight is extremely low, a sufficient coating film cannot be obtained and the heat resistance is reduced, or the unexposed part of the radiation-sensitive layer is liable to be eroded due to excessive alkali solubility of the radiation-sensitive layer, and vice versa. If the molecular weight is extremely high, the alkali solubility of the exposed portion will be low, and the defective portion of the exposed portion will be poor and the image reproducibility will be easily reduced. Specific examples of such a hydroxy (methane) styrene copolymer include, for example,

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

And the like. The above-mentioned base resins can be used alone or in combination of two or more. 60 to 99.9% by weight, preferably 70 to 9% by weight, based on the blending ratio of the base resin and the total solid content of the radiation-sensitive layer.
It is preferably 9.5% by weight, more preferably 80 to 99% by weight.
The present invention is characterized in that the bissulfonyldiazomethane compound which generates an acid upon exposure includes the compounds represented by the formulas (A1) to (A3).

R in the general formulas (A1) to (A3)¹,
R^Three, R^Four, R^Five, R⁶, R⁸, R ⁹, R^TenRepresented by
Examples of the optionally substituted alkyl group include those having 1 carbon atom.
Straight-chain or branched alkyl group having 6 to 6 carbon atoms
An alicyclic alkyl group, and the substituent is halogen
And an alkoxy group having 1 to 4 carbon atoms. R
¹And R^ThreeIs preferably an unsubstituted C 5 or C 6 fat
It is a cyclic alkyl group. R^Two, R^Four, R^Five, R⁶,
R⁸, R⁹, R^TenAs the halogen atom represented by
Preferred are fluorine, chlorine and bromine atoms,
Is a fluorine atom and may be substituted alkoxy
Groups include trifluoromethoxy, trichloromethoxy,
, Tribromomethoxy, pentafluoroethoxy, etc.
Number of carbon atoms which may be substituted by a substituent such as a halogen atom
1-4 alkoxy groups. Substituent R^TwoAs
Is preferably a halogen atom or may be substituted
It is an alkoxy group having 1 to 4 carbon atoms. Also, R^TwoSubstitution position
The position is not particularly limited, but ortho or para position is preferred.
From the balance of heat resistance sensitivity and resolution.
The la position is preferred. Also, R⁷Is an alkoxy containing 1 to 4 carbon atoms
A di-group is preferred. ⁹Is a p-position having 1 to 4 carbon atoms
Alkoxy groups are preferred and further R⁸And R^TenIs a hydrogen atom
It is preferred that

Specific examples of the compound represented by the formula (1A) include cyclohexylsulfonyl- (2-methoxyphenylsulfonyl) diazomethane, cyclohexylsulfonyl- (3-methoxyphenylsulfonyl) diazomethane, and cyclohexylsulfonyl- (4-methoxyphenyl). Sulfonyl) diazomethane, cyclopentylsulfonyl- (2-methoxyphenylsulfonyl) diazomethane, cyclopentylsulfonyl- (3-methoxyphenylsulfonyl) diazomethane, cyclopentylsulfonyl- (4-methoxyphenylsulfonyl) diazomethane, cyclohexylsulfonyl- (2-fluorophenylsulfonyl) Diazomethane, cyclopentylsulfonyl- (2-fluorophenylsulfonyl) diazomethane, cyclohexyl Ruphonyl- (4-fluorophenylsulfonyl) diazomethane, cyclopentylsulfonyl- (4-fluorophenylsulfonyl) diazomethane, cyclohexylsulfonyl- (4-chlorophenylsulfonyl) diazomethane, cyclopentylsulfonyl- (4-chlorophenylsulfonyl) diazomethane, cyclohexylsulfonyl- (3 -Trifluoromethylsulfonyl) diazomethane, cyclopentylsulfonyl-
(3-trifluoromethylsulfonyl) diazomethane,
Cyclohexylsulfonyl-4-trifluoromethoxysulfonyldiazomethane, cyclopentyl-4-trifluoromethoxysulfonyldiazomethane and the like can be mentioned. Specific examples of the compound represented by the formula (2A) include cyclohexylsulfonyl- (1,3,5-trimethylphenylsulfonyl) diazomethane, cyclohexylsulfonyl- (2,3,4-trimethylphenylsulfonyl) diazomethane, and cyclohexylsulfonyl-
(1,3,5-triethylphenylsulfonyl) diazomethane, cyclohexylsulfonyl- (2,3,4-triethylphenylsulfonyl) diazomethane, cyclopentylsulfonyl- (1,3,5-trimethylphenylsulfonyl) diazomethane, cyclopentylsulfonyl- (2 , 3,4-trimethylphenylsulfonyl) diazomethane and the like. Among them, cyclohexylsulfonyl- (1,3,5-trimethylphenylsulfonyl) diazomethane, cyclohexylsulfonyl- (4-
Methoxyphenylsulfonyl) diazomethane and cyclohexylsulfonyl- (4-fluorophenylsulfonyl) diazomethane.

Specific examples of the compound represented by the formula (3A) include 4-methoxyphenylsulfonyl- (4-methoxyphenylsulfonyl) diazomethane, 4-methoxyphenylsulfonyl- (2-methoxyphenylsulfonyl) diazomethane, Methoxyphenylsulfonyl- (3-methoxyphenylsulfonyl) diazomethane,
4-methoxyphenylsulfonyl- (phenylsulfonyl) diazomethane, 4-methoxyphenylsulfonyl-
(4-methylphenylsulfonyl) diazomethane, 4-
Methoxyphenylsulfonyl- (2-methylphenylsulfonyl) diazomethane, 4-methoxyphenylsulfonyl- (4-fluorophenylsulfonyl) diazomethane, 4-methoxyphenylsulfonyl- (4-trifluoromethylphenylsulfonyl) diazomethane, 4-ethoxyphenylsulfonyl -(4-methoxyphenylsulfonyl) diazomethane, 2-methoxy-4-methoxy-phenylsulfonyl- (4-methoxyphenylsulfonyl) cyazomethane and the like. In particular, cyclohexylsulfonyl- (4-methoxyphenylsulfonyl) diazomethane, cyclohexylsulfonyl- (2-methoxyphenylsulfonyl) diazomethane, and bis- (4-methoxyphenylsulfonyl) diazomethane are preferable because of their excellent crystallinity and easy synthesis.

The compounding ratio of the bissulfonyldiazomethane compound is 0.1 to 20% by weight, preferably 0.5 to 10% by weight, more preferably 0.5 to 5% by weight based on the total solid content of the radiation-sensitive layer.
% By weight. In the present invention, one or more other acid generators may be mixed as long as the effects of the present invention are not impaired.

As the suitable acid generator, any acid generator can be used as long as it generates an acid by light or electron beam used for exposure. Specifically, for example, tris (trichloromethyl)- s-triazine, tris (tribromomethyl) -s-triazine, tris (dibromomethyl) -s-triazine, 2,4-bis (tribromomethyl) -6-p-methoxyphenyl-s
Halogen-containing s-triazine derivatives such as -triazine, 1,2,3,4-tetrabromobutane, 1,1,1
Halogen-substituted paraffinic hydrocarbons such as 2,2-tetrabromoethane, carbon tetrabromide, and iodoform; halogen-substituted cycloparaffinic hydrocarbons such as hexabromocyclohexane, hexachlorocyclohexane, and hexabromocyclododecane; bis (trichloromethyl) benzene , Halogen-containing benzene derivatives such as bis (tribromomethyl) benzene, halogen-containing sulfone compounds such as tribromomethylphenylsulfone, trichloromethylphenylsulfone, 2,3-dibromosulfolane, and tris (2,3-dibromopropyl) isocyanurate Such as halogen-containing isocyanurate derivatives, triphenylsulfonium chloride, triphenylsulfonium methanesulfonate, and triphenylsulfonium trifluoromethanesulfate , Sulfonium salts such as triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroarsenate, triphenylsulfonium hexafluorophosphonate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium p-toluenesulfonate, diphenyl Iodonium tetrafluoroborate,
Diphenyliodonium hexafluoroarsenate,
Iodonium salts such as diphenyliodonium hexafluorophosphonate, methyl p-toluenesulfonate,
ethyl p-toluenesulfonate, butyl p-toluenesulfonate, phenyl p-toluenesulfonate, 1,2,2
3-tri (p-toluenesulfonyl) benzene, p-toluenesulfonic acid benzoin ester, methyl methanesulfonate, ethyl methanesulfonate, butyl methanesulfonate, 1,2,3-tri (methanesulfonyl) benzene, methanesulfonic acid Phenyl, methanesulfonic acid benzoin ester, methyl trifluoromethanesulfonate, ethyl trifluoromethanesulfonate, butyl trifluoromethanesulfonate, 1,2,3-tri (trifluoromethanesulfonyl) benzene, phenyl trifluoromethanesulfonate, trifluoromethanesulfonic acid Sulfonic acid esters such as benzoin ester, disulfones such as diphenyldisulfone, bis (phenylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazometh Sulfonic diazide such as emissions, o
O such as -nitrobenzyl-p-toluenesulfonate
-Nitrobenzyl esters, sulfone hydrazides such as N, N'-di (phenylsulfonyl) hydrazide, and the like. As the compound containing an orthoquinonediazide group, 1,2-benzoquinonediazide-4 is usually used.
Orthoquinonediazide compounds such as esters or amides such as sulfonic acid, 1,2-naphthoquinonediazide-4-sulfonic acid, and 1,2-naphthoquinonediazide-5-sulfonic acid. The compounding ratio of these acid generators is 0.01 to 5% by weight, preferably 0.1 to 3% by weight, based on the total solid content of the radiation-sensitive layer.

As the solvent for the radiation-sensitive composition in the present invention, any solvent can be used as long as it can dissolve the above-mentioned base resin and acid generator. Preferred solvents include 2-hexanone and cyclohexanone. Ketone solvents, cellosolve solvents such as methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, diethyl oxalate, ethyl pyruvate, ethyl-2-hydroxybutyrate, ethyl acetoacetate, butyl acetate, amyl acetate, Ester solvents such as ethyl butyrate, butyl butyrate, methyl lactate, ethyl lactate, methyl 3-methoxypropionate, and methyl 2-hydroxy-2-methylpropionate; propylene glycol monomethyl ether; propylene glycol monoethyl ether Propylene glycol solvents such as propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, and dipropylene glycol dimethyl ether; ketone solvents such as cyclohexanone, methyl amyl ketone and 2-heptanone Or a mixed solvent thereof, or a mixture obtained by further adding an aromatic hydrocarbon.

Additives can be added to the radiation-sensitive composition of the present invention to such an extent that the effects of the present invention are not impaired. Examples of the additive include a dissolution inhibitor, a surfactant, an organic acid, and an amine compound in the radiation-sensitive layer in an amount of 0.01 to 10% by weight,
Preferably, it can be contained in the range of 0.05 to 5% by weight. The dissolution inhibitor is a compound that controls the solubility of the unexposed portion of the alkali-soluble resin in an alkali developing solution, and may be a low-molecular compound or a high-molecular resin as long as it has a group that is eliminated by an acid catalyst. Preferred are compounds in which a hydrogen atom of an acidic functional group such as a phenolic hydroxyl group or a carboxyl group is protected by a group capable of leaving by an acid catalyst. Examples of low molecular weight compounds include bisphenol derivatives,
The following formula (3) or (4) represented by a phenolic compound such as a trisphenol derivative is exemplified.

[0031]

Embedded image

Wherein R ¹¹ , R ¹² , R ¹³ , R ¹⁴ and R
¹⁵ is each independently a halogen atom, an alkyl group, an alkoxy group or an aralkyl group, and a, b and c are each independently an integer ranging from 0 to 4. Further, R ¹³ and R ¹⁴ may form an alkylene ring containing them. R ^{16 to} R
²² is a hydrogen atom or an alkyl group, and d is independently an integer ranging from 0 to 3. )

The structure of the group capable of leaving by the acid catalysis is basically the same as the above-mentioned protecting group (Chemical Formula 3) or the protecting group (Chemical Formula 4).
In particular, a t-butyloxycarbonyl group,
A tetrahydropyral group, an ethoxyethyl group and the like are preferable. Furthermore, the dissolution inhibitors used in the present invention can be used alone or in combination of two or more. Examples of organic acids and amine compounds include JP-A-9-90639 and JP-A-9-9069.
JP-A-6001 can be mentioned.

When a resist pattern is formed on a semiconductor substrate using the radiation-sensitive coating composition of the present invention, the radiation-sensitive coating composition of the present invention dissolved in a solvent as described above is usually used. It can be used as a photoresist through the steps of pre-baking, transferring a pattern by exposure, baking after exposure, and developing after application. The semiconductor substrate is generally used as a substrate for manufacturing a semiconductor, and is a silicon substrate, a gallium arsenide substrate, or the like.

A spin coater is usually used for coating.
For exposure, 254 nm of a low-pressure mercury lamp, 157 nm, 193 nm, 222 nm using an excimer laser or the like as a light source.
Light of 248 nm or an electron beam is preferably used, and it is particularly advantageous to use an excimer laser as a light source. Light at the time of exposure may be broad instead of monochromatic light. Exposure by a phase shift method is also applicable.

The developer of the radiation-sensitive composition of the present invention includes:
Sodium hydroxide, potassium hydroxide, sodium carbonate,
Inorganic alkalis such as sodium silicate, sodium metasilicate, aqueous ammonia, primary amines such as ethylamine and n-propylamine, diethylamine, di-n
Secondary amines such as -propylamine; tertiary amines such as triethylamine and N, N-diethylmethylamine; quaternary ammonium salts such as tetramethylammonium hydroxide and trimethylhydroxyethylammonium hydroxide; To which alcohol, a surfactant and the like are added. The radiation-sensitive composition of the present invention is useful not only for the production of VLSI, but also for general IC production, mask production, image formation, liquid crystal screen production, color filter production or offset printing.

[0037]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the examples unless it exceeds the gist thereof. Synthesis Example 1 Synthesis of 1-ethoxyethylated polyvinylphenol Polyvinylphenol (weight average molecular weight 1720) was placed in a 1 L four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermometer.
0) After adding and dissolving 100 g and 500 mL of tetrahydrofuran, 36.0 g of ethyl vinyl ether was added and stirred for a while to form a uniform solution. 35%
0.5 g of hydrochloric acid was added, the mixture was heated to 40 ° C. by a water bath, and stirring was continued for 2 hours. Thereafter, 5 mL of 28% aqueous ammonia was added to the reaction solution, followed by stirring for 30 minutes. This reaction solution was dropped into 9 L of pure water, and the resulting precipitate was collected by filtration. Further, the precipitate was dissolved in acetone, and the solution was dropped into pure water to cause precipitation, thereby recovering a target resin.
The collected resin was dried under vacuum to obtain 100 g of 1-ethoxyethylated polyvinylphenol. The obtained resin was dissolved in deuterated acetone, and a proton NMR spectrum was measured. A signal of an aromatic hydrogen having a δ value of 6.2 to 7.0 and an acetal methine hydrogen having a δ value of 5.2 to 5.5 were obtained. When the acetalization rate was determined from the area ratio with the signal, it was 35.0.
%. Other polyvinyl phenol copolymers were similarly synthesized.

Synthesis Example 2 Cyclohexylsulfonyl-
Synthesis of (4-methoxyphenylsulfonyl) diazomethane (1) 12.1 g of paraformaldehyde and 60 g of toluene were added to a 1 L four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermometer, and stirred. added. Thereafter, the temperature of the reaction solution was raised to 40 ° C., and 60 g of a toluene solution of 35.4 g of cyclohexanethiol was added over 20 minutes. After completion of the dropwise addition, the reaction solution was stirred while maintaining the temperature at 50 ° C. After confirming the completion of the reaction by TLC, the aqueous phase was discarded and made alkaline with a saturated aqueous sodium carbonate solution to obtain a toluene solution of chloromethylcyclohexyl sulfide.

(2) 4-methoxybenzenethiol7.
4 g was placed in a 200 mL flask, and 45.2 g of a 5 wt% sodium hydroxide solution in ethanol was added and stirred.
While cooling the flask with water, the toluene solution of chloromethylcyclohexyl sulfide obtained in (1) 27.
8 g were added dropwise over 5 minutes. After stirring for 2 hours, the temperature was raised to 70 ° C., and the mixture was further stirred for 1 hour. After adding 500 mg of sodium tungstate to this reaction solution, 25 g of 30% hydrogen peroxide solution was added over 1 hour, and the mixture was stirred for 5 hours. After extraction with toluene and drying over anhydrous sodium sulfate, the solvent was distilled off under reduced pressure to obtain cyclohexylsulfonyl- (4-methoxyphenylsulfonyl) methane.

(3) 3.0 g of cyclohexylsulfonyl- (4-methoxyphenylsulfonyl) methane synthesized in (2) was placed in a flask, and 100 mL of ethanol was added and stirred. In addition, 5 ml of sodium hydroxide was added to this solution.
8.0 g of a wt% ethanol solution was added and stirred. The reaction solution was cooled from −5 ° C. to −10 ° C., and 10 mL of an ethanol solution of 2.0 g of p-toluenesulfonyl azide was added to 5 mL.
The mixture was dropped over a period of minutes, stirred for 3 hours and allowed to stand. It was left at 250 ° C. for 12 hours, and the target cyclohexylsulfonyl-
(4-Methoxyphenylsulfonyl) diazomethane was obtained.

Other cyclohexylsulfonyl- (substituted phenylsulfonyl) -diazomethanes were synthesized in the same manner. Also, 4-methoxyphenylsulfonyl (4-methoxyphenylsulfonyl) diazomethane is
Synthesis was performed in the same manner except that cyclohexylthiol was changed to 4-methoxyphenylthiol. Examples 1 to 8 and Comparative Examples 1 to 7 The following radiation-sensitive layer coating solutions

[0042]

[Table 4] Coating solution for radiation-sensitive layer Base resin 0.8g Resin described in Table 1 Acid generator Compound described in Table 1 0.016g Additive Tetraisopropanolamine 0.0016g Solvent Propylene glycol monomethyl 5g Ether acetate

[0043] An anti-reflection film (Brew
er Science Co., Ltd., DUV18) is spin-coated on a coated wafer, and placed on a hot plate at 80 ° C and 6 ° C.
The resist film was baked for 0 second to form a resist film having a thickness of 0.72 μm. The resist film on this substrate was exposed using a Nikon KrF excimer laser reduction projection exposure apparatus (NA = 0.42), and baked on a hot plate at 120 ° C. for 60 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute to form a resist image. The following items were evaluated. The results are shown in Table 1.

[Evaluation of Synthesis Difficulty] The synthesis difficulty was evaluated from the yield of the crystals of the target product (bissulfonyldiazomethane compound) formed in the reaction solution synthesized in the same manner as in Synthesis Example 2. Was. A: Crystals with a yield of 50% by weight or more were formed. B: Crystals having a yield of 20% by weight or more and less than 50% by weight were formed. C: Crystals with a yield of less than 20% by weight were formed. D: No crystal was generated. F: Indicates not evaluated.

[Evaluation of Sensitivity and Resolution] The resist pattern obtained after the development was observed with a scanning electron microscope to determine the sensitivity, that is, the exposure amount and resolution at which a 0.3 μm line and space was resolved at 1: 1. (Limit resolution) was evaluated. F: Indicates not evaluated.

[Evaluation of Heat Resistance] A sample on which an image having a limited resolution was formed on a silicon substrate was placed on a hot plate for 14 hours.
Bake at 0 ° C and 150 ° C for 5 minutes. After this,
A cross section of a 0.5 μm line pattern was cut out and observed with a scanning electron microscope to evaluate heat resistance. A: The corner of the pattern is completely left. B: Although the corner of the pattern remains, the pattern is considerably tapered. C: The corners of the pattern are partially shaved and becoming round. D: There are no pattern corners. F: Indicates not evaluated.

[Developability] A sample on which a pattern having a resolution of 0.5 μm and a line and space resolution of 1: 1 was formed was scanned and observed with a microscope to remove the exposed portion and reduce the film thickness of the unexposed portion. Was evaluated as follows. (Removability of exposed portion) A: There was no residual film of the radiation-sensitive layer in the exposed portion. B: There was a residual film in an exposed portion of less than 3%. C: There was a residual film of 3% or more and less than 7%. D: There was a residual film of 7% or more. (Film loss in unexposed area) A: There was no film loss. B: There was less than 2% film reduction. C: There was a film reduction of 2% or more and less than 5%. D: There was a film reduction of 5% or more.

[0048]

[Table 5]

[0049]

[Table 6]

[0050]

[Table 7]

[0051]

[Table 8]

[0052]

According to the radiation-sensitive composition of the present invention, by using a specific base resin and a sulfonyldiazomethane compound as its constituent components, the radiation-sensitive composition has a practically sufficient sensitivity despite having a resolving power equal to or higher than the conventional one. It has excellent heat resistance and is extremely useful in practice.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takaaki Niimi 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Chemical Corporation Yokohama Research Laboratory (72) Inventor Atsushi Fujita 1000 Kamoshida-cho, Aoba-ku, Yokohama-shi, Kanagawa Mitsubishi Chemical Corporation Yokohama Research Laboratory

Claims (12)

[Claims] 1. A radiation-sensitive composition comprising a film-forming resin and a bissulfonyldiazomethane compound which generates an acid upon exposure to light, wherein the bissulfonyldiazomethane compound has the following general formula (A1) to (A3). A compound represented by the formula: (Wherein, R ¹ and R ³ represent an optionally substituted aliphatic alkyl group, and R ² represents a halogen atom, an optionally substituted alkoxy group, a nitro group, a cyano group, a nitrile group or an amide group. R ⁴ , R ⁵ and R ⁶ each independently represent an alkyl group which may be substituted, a halogen atom, an alkoxy group which may be substituted, a nitro group, a cyano group, a nitrile group or an amide group; ⁷ is an optionally substituted alkoxyl group, R ^{8 to} R ¹⁰ are each independently a hydrogen atom, a halogen atom, an optionally substituted alkoxy group, an optionally substituted alkyl group,
Represents a nitro group, a cyano group, a nitrile group or an amide group. The following general formula (1) or (2) wherein the film-forming resin is at least 30 to 90 mol% of hydroxy (methyl) styrene and is eliminated by an acid. (Wherein, X ¹ to X ⁵ independently represent a hydrogen atom, an alkyl group or an alkoxy group having 1 to 4 carbon atoms, X ¹ and X ³ is may be formed a ring .X ⁶ carbon Which represents 10 to 60 mol% of hydroxy (methyl) styrene protected by a group represented by the following formula:
A radiation-sensitive composition, which is a hydroxy (methyl) styrene copolymer having a weight average molecular weight (Mw) of 2,000 to 70,000. 2. The radiation-sensitive composition according to claim 1, wherein the hydroxy-protecting group of the hydroxy (methyl) styrene copolymer is a group represented by the general formula (1). 3. The radiation-sensitive composition according to claim 2, wherein the hydroxy-protecting group of the hydroxy (methyl) styrene copolymer is an ethoxyethyl group. 4. R in the general formula (A1)¹And general formula
R in (A2) ^ThreeMay be substituted with an alicyclic a
The feeling according to claim 1, which is a alkyl group.
Radioactive composition. 5. The bissulfonyldiazomethane compound represented by the general formula (A1), wherein R ² is a halogen atom or an optionally substituted alkoxy group having 1 to 4 carbon atoms. The radiation-sensitive composition as described in the above. 6. The radiation-sensitive composition according to claim 5, wherein R ¹ is an unsubstituted alicyclic alkyl group having 5 or 6 carbon atoms. 7. The radiation-sensitive composition according to claim 5, wherein the substitution position of R ² is an ortho position. 8. A bissulfonyldiazomethane compound represented by the general formula (A2), wherein R ³ is an unsubstituted carbon atom having 5 carbon atoms.
5. The radiation-sensitive composition according to claim 4, wherein the composition is an alicyclic alkyl group. 9. A bissulfonyldiazomethane compound represented by the general formula (A3), wherein R ^{8 to} R ¹⁰ are hydrogen, an alkyl group which may have a substituent, or an alkoxy group which may have a substituent. 4. The radiation-sensitive composition according to claim 1, which is a fluorine atom. 10. The radiation-sensitive composition according to claim 9, wherein R ⁷ is an alkoxy group having 1 to 4 carbon atoms. 11. The radiation-sensitive composition according to claim 10, wherein R ⁹ is an alkoxy group having 1 to 4 carbon atoms at the p-position. 12. The radiation-sensitive composition according to claim 11, wherein R ⁸ and R ⁹ are hydrogen atoms.