JPH09222722A - Chemical amplification type radiation sensitive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a compsn. having high resolution and adaptable to half- micron lithography using radiation by incorporating a specified compd. as a solvent. SOLUTION: A coating film forming resin and a compd. generating an acid under radiation are dissolved as principal components in a compd. represented by the formula as a solvent to obtain the objective radiation sensitive compsn. In the formula, each of R1 -R3 is optionally halogen substd. 1-3C alkyl and R1 -R3 may be different from one another. The coating film forming resin is an alkali- soluble resin or a resin obtd. by protecting at least part of the alkali solubility imparting groups of the alkali-soluble resin with protective groups releasable in the presence of an acid catalyst. Novolak resin or polyacrylic acid is preferably used as the alkali-soluble resin. The generated acid is preferably sulfonic acid, sulfenic acid or sulfinic acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to radiation-sensitive compositions sensitive to radiation, and more particularly to radiation-sensitive coating compositions suitable as resists for producing semiconductor integrated circuits.

[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 started at present with a storage capacity of 4 Mbits. Along with this, the demand for photolithography technology, which is indispensable for the production of integrated circuits, has been increasing year by year. For example,
For production of 4M bit DRAM, 0.8 μm level lithography technology is required, and for 16M DRAM with higher integration, 0.5 μm level, 64 μm level
In MDRAM, it is expected that 0.35 μm level lithography technology will be required. Along with this,
There is a strong demand for the development of resists that can be applied to each lithography level. In such a flow, a chemically amplified resist has attracted attention as a resist suitable for ultrafine processing. The chemically amplified resist is a resist that controls the solubility of a radiation irradiation part in a developing solution by a catalytic action of an acid generated by irradiation with radiation such as ultraviolet rays, far ultraviolet rays, X-rays, electron rays.

Nowadays, as the ultra-miniaturization is further advanced, the wavelength used for resist exposure is also the i-line (365n) of a mercury lamp.
From m) to KrF excimer laser light (248 nm), the wavelength is becoming shorter. For example, in the case of a positive photoresist, conventionally, naphthoquinonediazide was used as a photosensitizer. However, this positive photoresist has a very low transmittance for light in the far ultraviolet region such as KrF excimer laser light and has a low transmittance. It is sensitive and has low resolution. As a new positive resist for solving such a problem, various chemically amplified positive photoresists have been proposed which are composed of an acid generator and a compound whose solubility in an alkali developing solution is increased by an acid catalyst reaction. In such a chemically amplified positive photoresist, in order to obtain high resolution, it is very important to have a structure of a compound whose solubility in an alkali developing solution is increased by an acid-catalyzed reaction. Further, as a peculiar problem in the chemically amplified positive photoresist, there is a problem of stability with respect to a delay time between exposure and post-exposure bake (post exposure bake). That is, if the time between the exposure and the post-exposure bake is long, the pattern size often changes due to the diffusion of the generated acid.

On the other hand, the problem of safety has been pointed out in recent years for ethyl cellosolve acetate, which has been used as a solvent for radiation-sensitive coating compositions, and a solvent which can replace it has been demanded. That is, it is said that ethyl cellosolve acetate produces ethoxyacetic acid in vivo and the alkoxyacetic acid is toxic (Chemical Economics, August 1988, p. 72, and European Chemical).
Industry Economy and Toxi
college Center Technical R
eport No. 4 July 30, 1982, and No. 17 April 19, 1985). As a solvent to replace 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 methyl ether acetate is disclosed in JP-A-61-7837. Propylene glycol alkyl ether acetates such as
No. 2-123444, methyl methoxyacetate, ethyl ethoxyacetate, methyl 2-oxy-2-methylpropionate (same as methyl 2-hydroxy-2-methylpropionate), ethyl 2-oxypropionate, 3- Monooxymonocarboxylic acid esters such as ethyl methoxypropionate have been proposed as solvents. However, because of their low polarity, among the components of the chemically amplified resist, the solubility of the acid generator is particularly insufficient, and it is difficult to obtain a stable and uniform resist solution during storage. In order to meet these requirements, the development of a high-performance radiation-sensitive coating composition has been earnestly made, but in addition to the performance such as the essential high resolution required from the process side to be used, the sensitivity,
It has been difficult to satisfy the uniformity of the coating film, the suppression of the pattern dimension variation occurring during the exposure between the chemically amplified resist and the post exposure bake, and the like.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a radiation-sensitive coating composition having high resolution which can be applied to half-micron lithography using radiation. is there. Another object of the present invention is to provide a radiation-sensitive coating composition which gives a good pattern shape without side wall roughness in a chemically amplified resist and has good stability with respect to a leaving time between exposure and post-exposure bake. To do.

[0006]

Means for Solving the Problems As a result of intensive studies by the present inventors, the above object of the present invention was achieved by using a solvent containing a specific compound as a solvent for a chemically amplified radiation-sensitive composition. I was found to be done. That is, the gist of the present invention is a chemically amplified radiation-sensitive composition comprising a film-forming resin, a compound that generates an acid upon irradiation with radiation, and a compound represented by the following formula (A) as a solvent. Exist in.

[0007]

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(R ₁ , R ₂ and R ₃ represent a C _{1 to} C ₃ alkyl group which may be substituted with a halogen atom and may be the same or different from each other.) The solvent is a bake before exposure. After that, it remains in the resist film, and it is considered that the property of this solvent has a great influence on the performance of the resist. In particular, in the chemically amplified resist containing the specific solvent of the present invention, not only the resolution is improved, but also a good pattern shape without sidewall roughness is provided, and further, stability with respect to the leaving time between exposure and post-exposure bake is provided. Is improved.

Hereinafter, the present invention will be described in detail. The radiation-sensitive composition of the present invention comprises a film-forming resin as a main component, a compound that generates an acid by radiation (hereinafter, abbreviated as an acid generator) in a solvent containing a compound represented by the above formula (A). It is a composition formed by dissolution. The coating film-forming resin used in the present invention is generally protected by an alkali-soluble resin or a group (hereinafter, abbreviated as a protecting group) capable of leaving at least a part of the group imparting alkali-solubility by an acid catalyst. Resin. The alkali-soluble resin is not particularly limited, but preferably novolac resin, polyacrylic acid, polyvinyl alcohol, polyhydroxystyrene, or a derivative thereof is used. Of these, polyvinylphenols such as novolac resin, polyhydroxystyrene or derivatives thereof are particularly preferable. The polyvinylphenols are, for example, resins obtained by polymerization of hydroxystyrene alone or copolymerization of hydroxystyrene and various vinyl monomers. As a vinyl monomer copolymerized with hydroxystyrene,
Acrylic acid, vinyl alcohol, or derivatives thereof are used.

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, 1,2,3-
Hydroxy aromatic compounds such as polyhydroxybenzenes which may be substituted with alkyl groups such as trihydroxybenzene, 1,2,3-trihydroxy-5-methylbenzene and 1,3,5-trihydroxybenzene, and formaldehyde, Paraformaldehyde, aliphatic aldehydes such as acetaldehyde, benzaldehyde, aromatic aldehydes such as hydroxybenzaldehyde, carbonyl compounds such as alkyl ketones such as acetone, for example, in the presence of an acid catalyst such as hydrochloric acid, sulfuric acid, oxalic acid, The thing manufactured by heating and polycondensing is 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 the absorbance in the short wavelength region. Specific examples of the polyvinylphenols include o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (o-hydroxyphenyl) propylene,
2- (m-hydroxyphenyl) propylene, 2- (p
A resin obtained by polymerizing hydroxystyrenes such as -hydroxyphenyl) propylene alone or in combination of two or more, and optionally the above vinyl monomer in the presence of a radical polymerization initiator, an anionic polymerization initiator or a cationic polymerization initiator is used. In addition, after the polymerization, hydrogenated products may be used to reduce the absorbance of the resin, and as long as the aromatic compound monomer does not adversely affect the present invention, substitution of halogen atoms, nitro groups, ester groups, etc. It may have a group.
The weight average molecular weight of polyvinylphenol is 1,000 or more and 100,000 or less, preferably 7,000 or more and 60,000 or less, more preferably 9,000 or more 60 in terms of polystyrene conversion value (gel permeation chromatography measurement). 000 or less is used. If the molecular weight of polyvinylphenol is smaller than this range, a sufficient coating film as a resist cannot be obtained and the heat resistance tends to be poor, and if it is larger than this range, the solubility of the exposed part in an alkaline developer becomes small. However, there is a tendency that a good resist pattern cannot be obtained.

The protecting group is not particularly limited as long as it is a group that can be removed by an acid, but a protecting group having a structure represented by the following formula (III) or (IV) is preferable, and t- Butyloxycarbonyl group, tetrahydropyranyl group and ethoxyethyl group are preferred.

[0013]

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[0014] (wherein, R _7, R ₈ represents a hydrogen atom, an alkyl group of _{C 1 ~C 10, R 9,} R 13 represents a C ₁ -C ₁₀ an alkyl group. Further, R ₇ and R ₈ or R ₇ and R ₉ may be bonded to each other to form a C _{3 to} C ₁₀ ring.)

Examples of the group that imparts alkali solubility include aromatic or aliphatic hydroxyl groups, carboxyl groups, and the like. Among them, phenolic hydroxyl groups are preferable, and at least a part of them is protected. It is an amount by which the alkali-solubility of the alkali-soluble resin is inhibited by the protection, and is not particularly limited, but preferably 10 mol% or more of the group imparting alkali-solubility, preferably 2
0 to 60 mol%.

The acid generator used in the present invention can be used without particular limitation as long as it can generate an acid by the light or electron beam used for exposure. Specifically, for example, tris ( Trichloromethyl) -s-
Triazine, tris (tribromomethyl) -s-triazine, tris (dibromomethyl) -s-triazine,
A halogen-containing s-triazine derivative such as 2,4-bis (tribromomethyl) -6-p-methoxyphenyl-s-triazine, 1,2,3,4-tetrabromobutane,
Halogen-substituted paraffinic hydrocarbons such as 1,1,2,2-tetrabromoethane, carbon tetrabromide, and iodoform,
Halogen-substituted cycloparaffin hydrocarbons such as hexabromocyclohexane, hexachlorocyclohexane, hexabromocyclododecane, halogen-containing benzene derivatives such as bis (trichloromethyl) benzene, bis (tribromomethyl) benzene, tribromomethylphenyl sulfone, trichloromethyl Phenyl sulfone,
Halogen-containing sulfone compounds such as 2,3-dibromosulfolane, halogen-containing isocyanurate derivatives such as tris (2,3-dibromopropyl) isocyanurate, triphenylsulfonium chloride, triphenylsulfonium methanesulfonate, triphenylsulfonium trifluoromethanesulfonate, Triphenylsulfonium p-toluenesulfonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium hexafluoroarsenate, triphenylsulfonium hexafluorophosphonate, and other sulfonium salts, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium p-toluenesulfonate, diphenyliodonium tetra Fluoroborate, dipheni Iodonium salts such as iodonium hexafluoroarsenate and diphenyliodonium hexafluorophosphonate, methyl p-toluenesulfonate, ethyl p-toluenesulfonate, butyl p-toluenesulfonate, phenyl p-toluenesulfonate, 1,2,3- Tri (p-toluenesulfonyl) benzene, p-toluenesulfonic acid benzoin ester, methyl methanesulfonate, ethyl methanesulfonate, butyl methanesulfonate, 1,2,3-tri (methanesulfonyl) benzene, phenyl methanesulfonate, Methanesulfonic acid benzoin ester, methyl trifluoromethanesulfonate, ethyl trifluoromethanesulfonate,
Butyl trifluoromethanesulfonate, 1,2,3-tri (trifluoromethanesulfonyl) benzene, phenyl trifluoromethanesulfonate, benzoin ester of trifluoromethanesulfonic acid, etc., disulfones such as diphenyldisulfone, di (phenyl) Sulfonyldiazides such as sulfonyl) diazomethane and di (cyclohexylsulfonyl) diazomethane, o-nitrobenzyl esters such as o-nitrobenzyl-p-toluenesulfonate, sulfone hydrazides such as N, N′-di (phenylsulfonyl) hydrazide Classes and the like are preferably used. The acid generator containing an orthoquinonediazide group is usually 1,2-benzoquinonediazide-4-sulfonic acid, 1,2-naphthoquinonediazide-4-sulfonic acid, 1,2-naphthoquinonediazide-5-sulfonic acid. Orthoquinonediazide compounds such as esters or amides are used. Among these acid generators, particularly preferred are compounds in which the generated acid is any of sulfonic acid, sulfenic acid and sulfinic acid. Specifically, triphenylsulfonium p
-Toluenesulfonate, diphenyliodonium p-
Onium sulfonates such as toluene sulfonate,
phenyl p-toluene sulfonate, sulfonates such as 1,2,3-tri (p-toluenesulfonyl) benzene, disulfones such as diphenyldisulfone, di (phenylsulfonyl) diazomethane, di (cyclohexylsulfonyl) diazomethane, etc. O-nitrobenzyl esters such as sulfonediazides and o-nitrobenzyl-p-toluenesulfonate are preferably used.

The radiation-sensitive composition according to the present invention basically comprises a coating film-forming resin as a main component and a compound capable of generating an acid upon irradiation, which is dissolved in a solvent represented by the above formula (A). Although it is a composition, more specifically, a composition having the following constitution is exemplified. Composition Example 1: A resin in which at least a part of the alkali-solubilizing group of the alkali-soluble resin is protected by a group capable of leaving by an acid catalyst, and an acid generator were dissolved in a solvent represented by the above formula (A). Positive type chemically amplified radiation sensitive composition

Composition Example 2: A resin, an acid generator, and a dissolution inhibitor represented by the above formula (A), in which at least a part of the groups imparting alkali solubility to the alkali-soluble resin are protected by a group capable of leaving by an acid catalyst. Positive-type chemically amplified radiation-sensitive composition dissolved in a solvent represented by Composition Example 3: A positive-type chemically amplified radiation-sensitive composition prepared by dissolving an alkali-soluble resin, an acid generator, and a dissolution inhibitor in the solvent represented by the formula (A). Chemically amplified radiation-sensitive composition

Composition example 4: Negative chemically amplified radiation-sensitive composition obtained by dissolving an alkali-soluble resin, an acid generator and a crosslinking agent in the solvent represented by the formula (A). Composition example 2 and composition example 3 above. In the case of the dissolution inhibitor, a compound that controls the solubility of the unexposed portion of the alkali-soluble resin in an alkali developing solution and has a group capable of leaving by an acid catalyst action is a high molecular weight resin or a high molecular weight resin. But good. A compound 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 action is preferable. Examples of the low molecular weight compound include the following structural formula (V) represented by a phenolic compound such as a bisphenol derivative and a trisphenol derivative.
Alternatively, a compound represented by (VI) may be mentioned.

[0020]

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(Wherein R ₁₄ , R ₁₅ , R ₁₆ , R ₁₇ and R
₁₈ is each independently a halogen atom, an alkyl type, an alkoxy group or an aralkyl group, and a, b and c are each independently an integer in the range of 0 to 4. R ₁₆ and R ₁₇ may form an alkylene ring containing them. R ₁₉ ~
R ₂₃ is a hydrogen atom or an alkyl group, and d is independently 0 to 3
Is an integer in the range

[0022]

[Chemical 6]

The structure of the group capable of leaving by acid catalysis is basically represented by the above-mentioned protecting group (III) or (IV), but especially t-butyloxycarbonyl group, tetrahydropyral group, ethoxyethyl group. Etc. are preferred. Furthermore, the dissolution inhibitors used in the present invention can be used alone or in combination of two or more. The alkali-soluble resin in the above composition examples and the resin in which at least a part of the groups imparting alkali-solubility of the alkali-soluble resin are protected with a group capable of being removed by an acid catalyst can be used alone or in combination of two or more kinds. . Among the above, polyvinylphenols are preferable as the alkali-soluble resin in Composition Examples 1 to 4, and polyvinylphenol is particularly preferable. The resin protected with a group capable of leaving by an acid catalyst in Composition Example 1 and Composition Example 2 is preferably one in which the hydroxyl group of polyvinylphenol is protected with a protective group as described above, and particularly the structural unit (I) The resin A containing the above or the resin B containing the structural unit (II) is preferable, and it is particularly preferable to use both as a mixture.

In the above structural units (I) and (II), R ₄
~ R ₆ and R ₁₀ ~ R ₁₂ are preferably hydrogen atoms, and
In the structural unit (I), the portion corresponding to the protecting group (III) is a tetrahydropyranyl group or an ethoxyethyl group,
In the structural unit (II), the portion corresponding to the protecting group (IV) is preferably a t-butyloxycarbonyloxy group. On the other hand, the cross-linking agent referred to in Composition Example 4 is a compound that reacts with an alkali-soluble resin by an acid catalyst action to cross-link the resin, and specifically, for example, hexamethoxymethylmelamine, methylolurea, etc. As the cross-linking agent for the negative chemically amplified radiation sensitive composition, known ones can be mentioned.

Additives can be added to the radiation-sensitive coating composition of the present invention to the extent that the effects of the present invention are not impaired.
Examples of additives include surfactants, sensitizers, nitrogen-containing compounds and the like. The radiation-sensitive composition in the present invention is
The invention is characterized by containing the compound represented by the above (A) as a solvent. Specific examples of the compound represented by the formula (A) include α-hydroxyisobutyric acid methyl ester, α-hydroxyisobutyric acid ethyl ester,
α-Hydroxyisobutyric acid butyl ester, α-hydroxy-α-trichloromethylpropionic acid methyl ester, α-hydroxy-α-trichloromethylpropionic acid ethyl ester, α-hydroxy-α-trichloromethylpropionic acid butyl ester, α-hydroxy -Α
-Methyl-butyric acid methyl ester, α-hydroxy-α-
Methyl-butyric acid ethyl ester, α-hydroxy-α-methyl-butyric acid butyl ester, α-hydroxy-α-ethyl-butyric acid methyl ester, α-hydroxy-α-ethyl-butyric acid ethyl ester, α-hydroxy-α-ethyl-
Butyric acid butyl ester, α-hydroxy-α-methylisovaleric acid methyl ester, α-hydroxy-α-methylisovaleric acid ethyl ester, α-hydroxy-α-methylisovaleric acid butyl ester, and the like, among which R ₁ to
R ₃ is preferably a C ₁ -C ₃ alkyl group, and particularly preferably a methyl group.

In the present invention, one or more other solvents may be mixed as long as the effects of the invention are not impaired. Suitable mixed solvents include ketone-based solvents such as 2-hexanone and cyclohexanone, methyl cellosolve,
Ethyl cellosolve, methyl cellosolve acetate, cellosolve solvent such as ethyl cellosolve acetate, diethyl oxalate, ethyl pyruvate, ethyl-2-hydroxybutyrate, ethyl acetoacetate, butyl acetate, amyl acetate, ethyl butyrate, butyl butyrate, Ester solvents such as methyl lactate, ethyl lactate and methyl 3-methoxypropionate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol mono Propylene glycol solvent such as butyl ether acetate, dipropylene glycol dimethyl ether, cyclo Cyclohexanone, methyl amyl ketone, 2
-A ketone solvent such as heptanone, a mixed solvent thereof, or a solvent to which an aromatic hydrocarbon is further added.

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 for the semiconductor substrate. It can be used as a photoresist after being coated on the surface thereof, pre-baked, transferred a pattern by exposure, baked after exposure, and developed. 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, high pressure mercury lamp 436nm, 365nm light,
254 nm of a low-pressure mercury lamp, 157 nm, 193 nm, 222 nm, 248 n using an excimer laser or the like as a light source
m light or electron beam is preferably used. Light at the time of exposure may be broad instead of monochromatic light. Also,
Exposure by the phase shift method is also applicable.

The developer of the radiation-sensitive coating composition of the present invention contains an inorganic alkali such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propyl. Primary amines such as amines, secondary amines such as diethylamine and di-n-propylamine, tertiary amines such as triethylamine and N, N-diethylmethylamine, tetramethylammonium hydroxide, trimethylhydroxy It is possible to use a quaternary ammonium salt such as ethylammonium hydroxide, or a salt obtained by adding an alcohol, a surfactant or the like thereto. The radiation-sensitive coating composition of the present invention has a super LS
Not only for manufacturing I, but for general IC manufacturing, mask manufacturing,
It is also useful for image formation, liquid crystal screen production, color filter production or offset printing.

[0030]

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 tetrahydropyranylated polyvinylphenol) 24 g of polyvinylphenol (weight average molecular weight 5200) and 320 ml of ethyl acetate are placed in a 1-liter Erlenmeyer flask.
Was added and dissolved uniformly, and then 3,4-dihydro-
2H-pyran 16.8 g was added, and 35% hydrochloric acid 0.3
g was added and stirring was continued for 4 hours. After the reaction, this reaction solution was neutralized with 140 ml of a saturated sodium hydrogen carbonate aqueous solution, and then the organic layer was washed with water three times. Furthermore, this organic layer was dried over anhydrous sodium sulfate and then concentrated to about 200 ml by a rotary evaporator. This concentrate is 1.5
The polymer was recovered by pouring it into liter of n-hexane. The precipitated polymer was vacuum dried to obtain 30.7 g of tetrahydropyranylated polyvinyl phenol. The obtained polymer was dissolved in deuterated acetone and the proton NMR spectrum was measured. The signal δ value of aromatic hydrogen and the signal δ value of acetal methine hydrogen were 5.2 to 5.5. When the acetalization rate was obtained from the area ratio with, it was 28.2%.

Synthesis Example 2 (Synthesis 1 of 1-Ethoxyethylated Polyvinyl Phenol) Polyvinyl phenol (weight average molecular weight: 4) was placed in a 1-liter four-necked flask equipped with a nitrogen introducing tube, a stirrer and a thermometer.
1400) and 300 ml of ethyl acetate were added and uniformly dissolved, and then 15.4 g of ethyl vinyl ether.
Was added and heated to 40 ° C. in a water bath. to this,
0.3 g of 35% hydrochloric acid was added and stirring was continued for 4 hours. After the reaction, this reaction solution was extracted with 400 ml of a 1% sodium hydrogen carbonate aqueous solution. The organic layer was dried over anhydrous sodium sulfate and then concentrated to about 100 ml with a rotary evaporator. This concentrated solution was poured into 1 liter of n-hexane to recover the polymer. The precipitated polymer was vacuum dried to obtain 32.5 g of 1-ethoxyethylated polyvinylphenol. The obtained polymer was dissolved in deuterated acetone, and the proton NMR spectrum was measured to find that the signal δ value of aromatic hydrogen was 6.2 to 7.0 and the signal δ value of acetal methine hydrogen was 5.2 to 5.5. When the acetalization rate was calculated from the area ratio of, it was 26.0%.

Synthesis Example 3 (Synthesis 2 of 1-ethoxyethylated polyvinylphenol) In the same manner as in Synthesis Example 3, 30 g of polyvinylphenol (weight average molecular weight 41400) and ethyl vinyl ether 1
From 4.4 g and 300 ml of ethyl acetate as a reaction solvent, 39.8 g of 1-ethoxyethylated polyvinylphenol was obtained.

The proton NMR spectrum of the obtained polymer was measured to find the acetalization rate, which was 29.1%.
It became. Synthetic Example 4 (Synthesis 3 of 1-ethoxyethylated polyvinylphenol) In the same manner as in Synthetic Example 3, 30 g of polyvinylphenol (weight average molecular weight 41400), ethyl vinyl ether 1
From 5.3 g and 300 ml of ethyl acetate as a reaction solvent, 36.4 g of 1-ethoxyethylated polyvinylphenol was obtained. The proton NMR spectrum of the obtained polymer was measured and the acetalization rate was determined to be 40.4.
%.

Synthesis Example 5 (Synthesis 1 of tert-butoxycarbonyloxylated polyvinylphenol) Polyvinylphenol (weight average molecular weight: 8) was placed in a 1-liter four-necked flask equipped with a nitrogen inlet tube, a stirrer and a thermometer.
660) 18.0 g and acetone 150 ml were added and dissolved uniformly, then N, N-dimethylaminopyridine 0.01 g was added as a catalyst, and the mixture was mixed with a water bath at 40
Heated to ° C. To this, 8.84 g of di-tert-butyl-di-carbonate was slowly added and stirring was continued for 4 hours. After the reaction, this reaction solution was poured into 1.5 liters of ion-exchanged water to collect the polymer. The polymer was dissolved in 100 ml of acetone and reprecipitated in 1.5 liter of ion-exchanged water to recover the polymer. This polymer was redissolved in 100 ml of acetone and reprecipitated in 1.5 liters of ion-exchanged water to recover the polymer, which was then vacuum dried to obtain 21.81 g of tert-butoxycarbonyloxylated polyvinylphenol. .
The obtained polymer was subjected to a differential thermogravimetric analysis to determine the weight reduction rate, and the protection rate was calculated. The protection rate was 27%. (Measurement conditions: temperature range 30 to 280 ° C., temperature rising rate 10 ° C./min, nitrogen flow rate 100 ml / min)

Synthesis Example 6 (Synthesis 2 of tert-butoxycarbonyloxylated polyvinylphenol) In the same manner as in Synthesis Example 5, 18.0 g of polyvinylphenol (weight average molecular weight 13400), di-tert-butyl-di-carbonate 8. 21.92 g of tert-butoxycarbonyloxylated polyvinylphenol was obtained from 84 g, acetone as a reaction solvent 150 ml, and N, N-dimethylaminopyridine 0.01 g as a catalyst.
The obtained polymer was subjected to a differential thermogravimetric analysis to determine the weight reduction rate, and the protection rate was calculated. The protection rate was 27%. (Measurement conditions: temperature range 30 to 280 ° C., heating rate 10 ° C./min, nitrogen flow rate 100 ml / min) Synthesis Example 7 (synthesis of tetrahydropyranylated trisphenol)

In a 1 liter Erlenmeyer flask, 19.5 g of trisphenol, 3,4-dihydro-2H-pyran 3
7.8 g and 220 g of ethyl acetate were added, 0.3 g of 35% hydrochloric acid was further added, and stirring was continued for 1 day at room temperature. After the reaction,
The reaction solution was neutralized with 140 ml of a saturated aqueous sodium hydrogen carbonate solution, and then the organic layer was washed with water three times. Further, this organic layer was dried over anhydrous sodium sulfate and then concentrated to obtain tetrahydropyranylated trisphenol.

Comparative Example 1 1.0 g of the resin synthesized in Synthesis Example 1, 0.43 g of the dissolution inhibitor synthesized in Synthesis Example 7, 0.07 g of triphenylsulfonium triflate as an acid generator, and propylene glycol monomethyl ether acetate. 5.4 g was mixed to obtain a resist photosensitive solution. This photosensitive solution is spin-coated on a silicon substrate and then 120
The resist film was baked at 90 ° C. for 90 seconds to form a 0.75 μm thick resist film. The resist film on this silicon substrate is applied to a NiF KrF excimer laser reduction projection exposure apparatus (NA = 0.4
2) was used and exposed with an energy amount of 51 mJ / cm ² , and then baked on a hot plate at 80 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resist pattern obtained after this development was observed with a scanning electron microscope to evaluate the resolving power between the exposure time and the post-exposure bake of 0 minutes and 30 minutes. As a result, the line and space of 0.32 μm was resolved at 0 minutes, but the resolution was deteriorated to the line and space of 0.38 μm at 30 minutes.

Example 1 1.0 g of the resin synthesized in Synthesis Example 1, 0.43 g of the dissolution inhibitor synthesized in Synthesis Example 7, 0.07 g of triphenylsulfonium triflate as a photoacid generator, and α-hydroxyiso Butyric acid methyl ester (5.4 g) was mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. The resist film on this silicon substrate was used for the NiF KrF excimer laser reduction projection exposure apparatus (NA = 0.42).
After exposure with an energy amount of 42 mJ / cm ² , the film was baked on a hot plate at 80 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. By observing the resist pattern obtained after this development with a scanning electron microscope, the resolving power between the exposure time and the post-exposure bake of 0 minutes and 30 minutes was evaluated. As a result, the line and space of 0.30 μm was resolved at 0 minutes and 30 minutes, and the performance of the resist was improved as compared with Comparative Example 1.

Comparative Example 2 0.8 g of the resin synthesized in Synthesis Example 4, 0.0056 g of triphenylsulfonium tosylate as an acid generator, and 4.6 g of propylene glycol monomethyl ether acetate were mixed to prepare a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. The resist film on the silicon substrate is processed by a NiF KrF excimer laser reduction projection exposure apparatus (N
A = 0.42) and exposed at an energy amount of 13.0 mJ / cm ² , and then on a hot plate at 80 ° C. for 90
Bake for 2 seconds. Thereafter, the resist film was washed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 hour.
Minutes. By observing the resist pattern obtained after this development with a scanning electron microscope, the resolving power between the exposure and the post-exposure bake was evaluated for 0 minutes. As a result, the line-and-space resolution was 0.32 μm.

Example 2 0.8 g of the resin synthesized in Synthesis Example 4, as a photo-acid generator,
Triphenylsulfonium tosylate 0.0056 g,
And α-hydroxyisobutyric acid methyl ester 4.6 g
Were mixed to obtain a resist photosensitive solution. This photosensitive solution is spin-coated on a silicon substrate and then 120
The resist film was baked at 90 ° C. for 90 seconds to form a resist film having a film thickness of 1.0 μm. The resist film on this silicon substrate is made by Nikon K
rF excimer laser reduction projection exposure system (NA = 0.4
2) was used and exposed to an energy amount of 42.5 mJ / cm ² , and then baked on a hot plate at 80 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. By observing the resist pattern obtained after this development with a scanning electron microscope, the resolving power between the exposure and the post-exposure bake was evaluated for 0 minutes. As a result, 0.
The line and space of 28 μm was resolved in a good shape, and the resist performance was improved as compared with Comparative Example 2.

Comparative Example 3 0.6 g of the resin synthesized in Synthesis Example 3, 0.067 g of the resin synthesized in Synthesis Example 6, 0.023 g of triphenylsulfonium tosylate as an acid generator, and propylene glycol monomethyl ether acetate. 6 g was mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate, and then on a hot plate at 120 ° C for 9
The resist film was baked for 0 second to form a resist film having a film thickness of 0.75 μm. The resist film on the silicon substrate is a Nikon Kr
F excimer laser reduction projection exposure system (NA = 0.42)
Was used for exposure with an energy amount of 18.5 mJ / cm ² , and then baked on a hot plate at 80 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. By observing the resist pattern obtained after this development with a scanning electron microscope, the resolving power between the exposure and the post-exposure bake was evaluated for 0 minutes. As a result, 0.
The line and space resolution was 40 μm.

Example 3 0.6 g of the resin synthesized in Synthesis Example 3, 0.067 g of the resin synthesized in Synthesis Example 6, 0.023 g of triphenylsulfonium tosylate as an acid generator, and α-hydroxyisobutyric acid methyl ester. 5.4 g was mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. The resist film on the silicon substrate was formed by using a KrF excimer laser reduction projection exposure device (NA = 0.42) manufactured by Nikon Corporation.
After exposure with an energy amount of 0 mJ / cm ² , baking was performed on a hot plate at 80 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. By observing the resist pattern obtained after this development with a scanning electron microscope, the resolving power between the exposure and the post-exposure bake was evaluated for 0 minutes. As a result, the line and space of 0.28 μm was resolved in a good shape, and the resist performance was improved as compared with Comparative Example 2.

Example 4 A resist (FC430, FC430,
A resist photosensitive solution containing 100 ppm of Sumitomo 3M Ltd. was prepared. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. The resist film on this silicon substrate was exposed with an energy amount of 44.0 mJ / cm ² using a KrF excimer laser reduction projection exposure device (NA = 0.42) manufactured by Nikon Corporation, and then exposed on a hot plate at 80 ° C. for 90 minutes. Bake for a second.
Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. By observing the resist pattern obtained after this development with a scanning electron microscope, the resolving power between the exposure and the post-exposure bake was evaluated for 0 minutes. As a result, 0.28μ
The line and space of m was resolved in a good shape, and the resist performance was improved as compared with Comparative Example 3.

Comparative Example 4 0.35 g of the resin synthesized in Synthesis Example 3, 0.15 g of the resin synthesized in Synthesis Example 5, 0.0175 g of diphenyliodonium tosylate as a photoacid generator, and propylene glycol monomethyl ether acetate.2. 7 g was mixed, and triisopropanolamine was further added in an amount equal to 1/10 mol of the photoacid generator to prepare a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 110 ° C. for 90 seconds to give a film thickness of 0.75 μm.
m as the resist film. The resist film on the silicon substrate was exposed with an energy amount of 11.0 mJ / cm ² using a KrF excimer laser reduction projection exposure device (NA = 0.42) manufactured by Nikon Corporation, and then 100 on a hot plate.
It was baked at 90 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. By observing the resist pattern obtained after this development with a scanning electron microscope, the resolving power between the exposure time and the post-exposure bake of 0 minutes and 30 minutes was evaluated. As a result, the line and space of 0.26 μm was resolved at 0 minutes, but the resolution was deteriorated to the line and space of 0.34 μm at 30 minutes.

Example 5 0.35 g of the resin synthesized in Synthesis Example 3, 0.15 g of the resin synthesized in Synthesis Example 5, 0.0175 g of diphenyliodonium tosylate as an acid generator, and α-hydroxyisobutyric acid methyl ester 4 0.1 g of triisopropanolamine and a surfactant (FC430, Sumitomo 3M Limited) in an amount of 1/10 molar equivalent of the photoacid generator.
(Manufactured by Mitsui Chemical Co., Ltd.) was added as a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 110 ° C. for 90 seconds to give a film thickness of 0.75 μm.
m as the resist film. The resist film on the silicon substrate was exposed with an energy amount of 18.5 mJ / cm 2 using a KrF excimer laser reduction projection exposure device (NA = 0.42) manufactured by Nikon Corporation, and then 100 on a hot plate.
It was baked at 90 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resist pattern obtained after this development was observed with a scanning electron microscope to evaluate the resolving power between the exposure time and the post-exposure bake of 0 minutes and 30 minutes. As a result, a 0.26 μm line and space was resolved at 0 minutes, and a line and space of 0.
Resolving power was achieved up to a line and space of 30 .mu.m, and the stability with respect to the leaving time between the exposure and the post-exposure bake was improved as compared with Comparative Example 4.

Example 6 0.35 g of the resin synthesized in Synthesis Example 3, 0.15 g of the resin synthesized in Synthesis Example 5, 0.0175 g of diphenyliodonium tosylate as an acid generator, and α-hydroxyisobutyric acid methyl ester / Propylene glycol monomethyl ether acetate mixed solvent (mixing ratio 4: 1)
4.1 g were mixed, and triisopropanolamine was further added to a surfactant (FC43
0, 100 ppm of Sumitomo 3M Ltd. was added to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 110 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. The resist film on this silicon substrate was exposed using a NiF KrF excimer laser reduction projection exposure apparatus (NA = 0.42).
After exposure with an energy amount of 11.4 mJ / cm ² , baking was performed on a hot plate at 100 ° C. for 90 seconds. Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. The resist pattern obtained after this development was observed with a scanning electron microscope to evaluate the resolving power between the exposure time and the post-exposure bake of 0 minutes and 30 minutes. As a result, a line and space of 0.26 μm was resolved in the case of 0 minutes, and a line and space of 0.26 μm was resolved in the case of 30 minutes, which was between the exposure and the post-exposure bake as compared with Comparative Example 4. The stability of the pesticides against the storage time was improved.

Comparative Example 5 0.8 g of the resin synthesized in Synthesis Example 2, 0.089 g of the resin synthesized in Synthesis Example 6, 0.031 g of triphenylsulfonium tosylate as an acid generator, and propylene glycol monomethyl ether acetate. 8 g was mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate, and then on a hot plate at 120 ° C for 9
The resist film was baked for 0 second to form a resist film having a film thickness of 0.75 μm. The resist film on the silicon substrate is a Nikon Kr
F excimer laser reduction projection exposure system (NA = 0.42)
Was used for exposure with an energy amount of 9.0 mJ / cm ² , and then baked on a hot plate at 80 ° C. for 90 seconds.
Thereafter, the resist film was developed with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 1 minute. When the resist pattern obtained after this development was observed with a scanning electron microscope, it was found to be a defective pattern shape with conspicuous side wall roughness.

Example 7 0.8 g of the resin synthesized in Synthesis Example 2, 0.089 g of the resin synthesized in Synthesis Example 6, 0.031 g of triphenylsulfonium tosylate as an acid generator, and α-hydroxyisobutyric acid methyl ester 4.8 g was mixed to obtain a resist photosensitive solution. This photosensitive solution was spin-coated on a silicon substrate and baked on a hot plate at 120 ° C. for 90 seconds to form a resist film having a film thickness of 0.75 μm. The resist film on the silicon substrate was set to 9.0 using a NiF KrF excimer laser reduction projection exposure apparatus (NA = 0.42).
After exposure with an energy amount of mJ / cm ² , the film was baked on a hot plate at 80 ° C. for 90 seconds. After that, the resist film was treated with tetramethylammonium hydroxide 2.
It was developed with a 38% by weight aqueous solution for 1 minute. When the resist pattern obtained after this development was observed with a scanning electron microscope, the side wall roughness was improved as compared with Comparative Example 6, and a good pattern shape was obtained. The compositions and results of each Example and Comparative Example are summarized in Table-1 to Table-3.

[0049]

[Table 1]

[0050]

[Table 2]

[0051]

[Table 3]

[0052]

INDUSTRIAL APPLICABILITY The present invention achieves high resolution by using a solvent containing a specific compound. Moreover, the radiation-sensitive coating composition of the present invention is stable with respect to the leaving time between exposure and baking after exposure, and the resist pattern obtained by using it has a good shape without sidewall roughness. And is extremely useful in practice.

Claims (4)

[Claims] 1. A chemically amplified radiation-sensitive composition comprising a film-forming resin, a compound that generates an acid upon irradiation with radiation, and a compound represented by the following formula (A) as a solvent. Embedded image (R ₁ , R ₂ and R ₃ are C ₁ which may be substituted with a halogen atom.
To C ₃ alkyl groups, which may be the same or different from each other. ) 2. The coating film-forming resin is a resin in which at least a part of the alkali-solubilizing groups of the alkali-soluble resin is protected by a group capable of leaving by an acid catalyst action. The chemically amplified radiation-sensitive composition according to 1. 3. The chemically amplified radiation-sensitive composition according to claim 1, wherein the film-forming resin is an alkali-soluble resin, and the chemically amplified radiation-sensitive composition further contains a crosslinking agent. Stuff. 4. A resin A containing the structural unit (I) shown below, or a resin having the structural unit (I) shown below, in which at least a part of the groups imparting alkali solubility to the alkali-soluble resin is protected by a group capable of leaving by acid catalysis. The chemically amplified radiation-sensitive composition according to claim 2, further comprising a resin B containing (II). Embedded image (However, R ₄ , R ₅ , R ₆ , R ₁₀ , R ₁₁ , and R ₁₂ are hydrogen atoms,
Represents a C _{1 to} C ₄ alkyl group, R ₇ and R ₈ are hydrogen atoms, and C ₁ to
Represents a C ₁₀ alkyl group, and R ₉ and R ₁₃ represent a C _{1 to} C ₁₀ alkyl group. Further, R ₇ and R ₈ or R ₇ and R ₉ may be bonded to each other to form a C _{3 to} C ₁₀ ring. )