JP2960656B2 - Positive resist composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive resist composition, more specifically, a resist pattern having high sensitivity, high resolution, heat resistance and good sectional shape.
The present invention relates to a chemically amplified positive resist composition useful as a resist for e-UV or excimer laser.

[0002]

2. Description of the Related Art Conventionally, in the process of manufacturing semiconductor devices such as ICs and LSIs, fine processing by lithography using a photoresist composition has been performed. This involves forming a thin film of a photoresist composition on a silicon wafer, irradiating it with actinic rays such as ultraviolet rays through a mask pattern on which a semiconductor device pattern is drawn, and then protecting the resist pattern obtained by development. This is a method of etching the silicon wafer as a film. As a preferred photoresist composition used in this method, a positive photoresist composition in which a photosensitive component comprising a quinonediazide group-containing compound is combined with an alkali-soluble novolak resin for forming a coating film is known.

However, in recent years, the degree of integration of semiconductor devices has rapidly increased, and in the manufacture of VLSI and the like, the processing accuracy of an ultrafine pattern in a submicron region or a quarter micron region has been required. Accordingly, the exposure wavelength also tends to be shorter from g-line to i-line, deep-UV, and even excimer laser such as KrF laser. Currently, lithography using deep-UV or excimer laser is in this field. It is drawing attention as an important processing technology.

A conventional novolak-quinonediazide-based resist for g-line or i-line has a large absorption of deep-UV or excimer laser light. Resist is expected.

The above-mentioned chemically amplified resist is a resist utilizing the catalytic action of an acid generated by irradiation, and has a high sensitivity and resolution, and is a compound capable of generating an acid upon irradiation (hereinafter referred to as acid generation). Agent) can be used in a small amount. There are two types of the chemically amplified resist, a positive type and a negative type. The former positive type resist is generally a resin component (hereinafter referred to as resin) whose solubility in an aqueous alkali solution is increased by the action of an acid generator and generated acid. Components). On the other hand, a negative resist is composed of an acid generator, a crosslinking agent, and an alkali-soluble resin component.

As such a chemically amplified positive resist, for example, the hydroxyl group of polyvinyl phenol is tertiary.
A resist using a resin component substituted with a t-butoxycarbonyloxy group or the like and an onium salt as an acid generator is known, and a polymer of p- (tert-butoxycarbonyloxy) styrene and naphthoquinone-1,2-diazide- A chemically amplified positive radiation-sensitive composition comprising an esterified product of 4-sulfonic acid and bisphenol A (JP-A-3-249654) is also known.

However, the above-mentioned existing chemically amplified positive resists do not always have sufficient light transmittance to deep-UV or excimer laser light, and have sensitivity, resolution, heat resistance and cross-section of resist patterns. The shape was not sufficiently satisfactory, and the resist was not practically satisfactory.

[0008]

The inventors of the present invention have conducted intensive studies to develop a chemically amplified positive resist composition free of the above-mentioned problems.
When a mixture of polyhydroxystyrene in which a specific ratio of hydroxyl groups is substituted with a tert-butoxycarbonyloxy group and polyhydroxystyrene in which a specific ratio of hydroxyl groups are substituted with a specific residue is used, deep-UV or excimer Completed the present invention by finding that a chemically amplified positive resist composition capable of forming a resist pattern having excellent light transmittance to laser light, high sensitivity, high resolution, heat resistance and a good cross-sectional shape can be obtained. It was done. Ie

The present invention provides a chemically amplified positive resist composition which is excellent in light transmittance with respect to deep-UV and excimer laser light, and which can form a resist pattern having high sensitivity, high resolution, heat resistance and a good sectional shape. The purpose is to provide things.

[0010]

In order to achieve the above object, the present invention provides a positive resist composition containing a resin component and an acid generator, wherein the resin component comprises (A) 10 to 60 hydroxyl groups.
Mole% of polyhydroxystyrene substituted with tert-butoxycarbonyloxy group and 10 to 10% of (B) hydroxyl group.
60 mol% is a general formula 2

[0011]

Embedded image (Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is a methyl group or an ethyl group, and R ³ is a lower alkyl group). And a positive resist composition.

[0012] The resin component has a component (A) of 10 to 70%.
% By weight and 30 to 90% by weight of the component (B), preferably 20 to 50% by weight of the component (A) and 50 to 8% by weight of the component (B).
0% by weight, the acid generated from the acid generator decomposes the tert-butoxycarbonyloxy group and the residue of the general formula 2, and these dissolve the resin component and the tert-butoxycarbonyloxy. The dissolution inhibiting ability of the group is appropriately balanced, and high sensitivity and high resolution can be achieved. If the compounding ratio of the resin component deviates from the above range, these characteristics cannot be obtained.

The component (A) is used to convert the hydroxyl group of polyhydroxystyrene with, for example, di-tert-butyl-di-carbonate according to a known substitution reaction.
Substituted with a butoxycarbonyloxy group, the substitution rate of which is 10 to 60 mol%, preferably 20 to 50 mol%
Is preferred. If the substitution rate is less than 10 mol%, a pattern having an excellent shape cannot be obtained, and if it exceeds 60 mol%, the sensitivity of the resist is lowered, which is not preferable. In practice, 20 to 50 mol% is effective.

On the other hand, the component (B) accounts for 10 to 60 mol%, preferably 20 to 5 mol% of the hydroxyl groups of the polyhydroxystyrene.
0 mol% is a compound substituted with the residue of the general formula 2,
It is obtained by reacting polyhydroxystyrene with, for example, 1-chloro-1-ethoxyethane, 1-chloro-1-methoxypropane, and the like. The residue of the general formula 2 includes 1-methoxyethoxy group, 1-ethoxyethoxy group, 1-n-propoxyethoxy group, 1-isopropoxyethoxy group, 1-n-butoxyethoxy group,
-Isobutoxyethoxy group, 1- (1,1-dimethylethoxy) -1-methylethoxy group, 1-methoxy-1-
Methylethoxy group, 1-ethoxy-1-methylethoxy group, 1-n-propoxy-1-methylethoxy group, 1-
Isobutoxy-1-methylethoxy group, 1-methoxy-
Examples thereof include an n-propoxy group and a 1-ethoxy-n-propoxy group. In particular, a 1-ethoxyethoxy group and 1
A -methoxy-n-propoxy group is preferred because sensitivity and resolution are improved in a well-balanced manner. The substitution rate is 10 mol%
If it is less than 60, a pattern having an excellent shape cannot be obtained.
If it exceeds mol%, the sensitivity of the resist is lowered, which is not preferable. Practically, 20 to 50 mol% is effective.

The weight-average molecular weight of the resin component is in the range of 3,000 to 30,000 based on polystyrene based on gel permeation chromatography (GPC). When the weight-average molecular weight is less than the above range, the coating properties are poor, and when the weight-average molecular weight exceeds the upper limit range, the solubility in an aqueous alkaline solution is reduced.

As the acid generator used in the present invention, those which are conventionally known as acid generators can be used.
Although there is no particular limitation, specifically, (a) bis (p-toluenesulfonyl) diazomethane, methylsulfonyl-p-
Toluenesulfonyldiazomethane, 1-cyclohexylsulfonyl-1- (1,1-dimethylethylsulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, bis (1-methylethylsulfonyl) diazomethane, bis (cyclohexylsulfonyl) diazomethane , Bis (2,4-dimethylphenylsulfonyl) diazomethane, bis (4-ethylphenylsulfonyl) diazomethane, bis (3-methylphenylsulfonyl) diazomethane, bis (4-methoxyphenylsulfonyl) diazomethane, bis (4-fluorophenylsulfonyl) ) Bissulfonyldiazomethanes such as diazomethane, bis (4-chlorophenylsulfonyl) diazomethane, bis (4-tert-butylphenylsulfonyl) diazomethane (B) 2-methyl-2-(p-
Toluenesulfonyl) propiophenone, 2- (cyclohexylcarbonyl) -2- (p-toluenesulfonyl) propane, 2-methanesulfonyl-2-methyl-
Sulfonylcarbonylalkanes such as (4-methylthio) propiophenone and 2,4-dimethyl-2- (p-toluenesulfonyl) pentan-3-one; (c) 1-
p-toluenesulfonyl-1-cyclohexylcarbonyldiazomethane, 1-diazo-1-methylsulfonyl-
4-phenyl-2-butanone, 1-cyclohexylsulfonyl-1-cyclohexylcarbonyldiazomethane,
1-diazo-1-cyclohexylsulfonyl-3,3-
Dimethyl-2-butanone, 1-diazo-1- (1,1-
Dimethylethylsulfonyl) -3,3-dimethyl-2-
Butanone, 1-acetyl-1- (1-methylethylsulfonyl) diazomethane, 1-diazo-1- (p-toluenesulfonyl) -3,3-dimethyl-2-butanone,
-Diazo-1-benzenesulfonyl-3,3-dimethyl-2-butanone, 1-diazo-1- (p-toluenesulfonyl) -3-methyl-2-butanone, 2-diazo-2
-Cyclohexyl (p-toluenesulfonyl) acetate, 2
Tert-butyl diazo-2-benzenesulfonylacetate, isopropyl 2-diazo-2-methanesulfonylacetate, cyclohexyl 2-diazo-2-benzenesulfonylacetate, 2-diazo-2- (p-toluenesulfonyl)
Sulfonylcarbonyldiazomethanes such as tert-butyl acetate, (d) 2-nitrobenzyl p-toluenesulfonate, 2,6-dinitrobenzyl p-toluenesulfonate, 2,4-dinitrobenzyl p-trifluoromethylbenzenesulfonate Nitrobenzyl derivatives such as, (e) methanesulfonic acid ester of pyrogallol,
Pyrogallol benzenesulfonate, pyrogallol p-toluenesulfonate, pyrogallol p-methoxybenzenesulfonate, pyrogallol mesitylenesulfonate, pyrogallol benzylsulfonate, alkyl gallate methanesulfonate, gallic Alkyl benzenesulfonate, alkyl gallate p-toluenesulfonate, alkyl gallate p-methoxybenzenesulfonate, alkyl gallate mesitylenesulfonate, alkyl gallate benzylsulfonate, etc. Examples thereof include a polyhydroxy compound and an aliphatic or aromatic sulfonic acid ester. The alkyl group in the alkyl gallate,
An alkyl group having 1 to 15 carbon atoms, particularly an octyl group and a lauryl group are preferred. Among the above-mentioned acid generators, bissulfonyldiazomethanes are particularly preferred, and bis (cyclopentane)
Rohexylsulfonyl) diazomethane and bis (2,4
-Dimethylphenylsulfonyl) diazomethane is preferred. One of these acid generators may be used alone, or two or more thereof may be used in combination.

The mixing ratio of the acid generator is 10
The ratio is 1 to 20 parts by weight, preferably 2 to 10 parts by weight with respect to 0 parts by weight. If the amount of the acid generator is less than 1 part by weight, the effect is insufficient. If the amount exceeds 20 parts by weight, the acid generator cannot be completely dissolved in the solvent and the miscibility with the resin component is poor.

The positive resist composition of the present invention preferably contains a light absorbing agent in order to improve sensitivity and resolution in addition to the above resin component and acid generator. As the light absorbing agent,
For example, mercaptooxazole, mercaptobenzoxazole, mercaptooxazoline, mercaptobenzothiazole, benzoxazolinone, benzothiazolone, mercaptobenzimidazole, urazole, thiouracil, mercaptopyrimidine , benzophenone and derivatives thereof can be mentioned, and especially benzophenone is sensitive and It can be preferably used because it has an effect of improving the resolution and also has the effect of suppressing the influence of standing waves and forming a rectangular resist pattern without forming a wavy cross-sectional shape. The light-absorbing agent is used in an amount not exceeding 30% by weight, preferably 0.5 to 15% by weight, based on the total amount of the resin component and the acid generator. If the amount is more than 30% by weight, the profile shape is unfavorably deteriorated.

The positive resist composition of the present invention contains an organic carboxylic acid compound, specifically, formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipine Monovalent or polyvalent aliphatic carboxylic acids such as acids, 1,1-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,1- Alicyclic carboxylic acids such as cyclohexyl diacetate, acrylic acid, crotonic acid, isocrotonic acid, 3-butenoic acid, methacrylic acid, 4-pentenoic acid, propiolic acid, 2-butyric acid, maleic acid, fumaric acid, acetylene carboxylic acid Such as unsaturated aliphatic carboxylic acids, oxycarboxylic acids such as oxyacetic acid, methoxyacetic acid, ethoxyacetic acid, etc. Shikarubon acid, keto acids such as pyruvic acid, generally formalized 3

[0020]

Embedded image [ Wherein , R ₄ and R ₅ each independently represent a hydrogen atom, a hydroxyl group, a nitro group, a carboxyl group, or a vinyl group (however, unless R ₄ and R ₅ are both hydrogen atoms)]
And general formula 4

[0021]

Embedded image [In the formula, n represents 0 or an integer of 1 to 10]. Examples of the aromatic carboxylic acid compound represented by the general formula 3 include p-hydroxybenzoic acid, o-hydroxybenzoic acid, 2-hydroxy-3-nitrobenzoic acid, 3,5
-Dinitrobenzoic acid, 2-nitrobenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid,
2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 2-vinylbenzoic acid, 4-vinylbenzoic acid, phthalic acid, terephthalic acid, isophthalic acid, etc. Benzoic acid having a substituent at the o-position, for example, o-hydroxybenzoic acid, o-nitrobenzoic acid, phthalic acid and the like are preferred.

As the aromatic carboxylic acid compound represented by the general formula (4), it is possible to use only one compound of n in the formula or a combination of different compounds. SAX (trade name, manufactured by Mitsui Toatsu Chemicals, Inc.) commercially available as a phenol compound is preferably used.

The organic carboxylic acid compounds may be used alone or in combination of two or more. A good resist pattern having a good cross-sectional shape can be formed by blending these organic carboxylic acid compounds. Particularly, an aromatic carboxylic acid compound represented by the general formula 4 can form a rectangular cross-sectional shape. It is suitable.

The amount of the organic carboxylic acid compound to be added is 0.01 to 0.01 with respect to the total amount of the resin component and the acid generator.
It is used in an amount of 1% by weight, preferably 0.05 to 0.5% by weight. The compounding amount of the organic carboxylic acid compound is 0.01
If the content is less than 1% by weight, a resist pattern having a good cross-sectional shape cannot be obtained, and if the content exceeds 1% by weight, the developability deteriorates.

The positive resist composition of the present invention is preferably used in the form of a solution in which the above components are dissolved in a solvent. Examples of such solvents include ketones such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isoamyl ketone; ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol or dipropylene glycol. Polyhydric alcohols such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether of propylene glycol monoacetate and derivatives thereof; cyclic ethers such as dioxane; and methyl lactate, ethyl lactate and methyl acetate , Ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethoxypropyl It can be mentioned esters such as phosphate ethyl. These may be used alone or as a mixture of two or more.

The positive resist composition of the present invention may further contain, if desired, a miscible additive, for example, an additional resin, a plasticizer, a stabilizer, a colorant, and a surfactant for improving the performance of the resist film. Such commonly used materials as described above can be added and contained.

As a method of using the positive resist composition of the present invention, a method of forming a resist pattern according to a conventional photoresist technique is used, and preferred examples thereof will be described below. First, on a support such as a silicon wafer, a solution prepared by dissolving a resin component, an acid generator and, if necessary, a light absorbing agent and an organic carboxylic acid compound and various additives to be added as required in the above-described solvent. It is applied with a spinner or the like and dried to form a photosensitive layer, which is irradiated with an excimer laser beam through a desired mask pattern by a reduction projection exposure apparatus or the like, and then this is developed with a developing solution, for example, 1 to 10% by weight. Development processing is performed using a weakly alkaline aqueous solution such as an aqueous solution of tetramethylammonium hydroxide. With this forming method, an image faithful to the mask pattern can be obtained.

[0028]

Now, the present invention will be described in further detail with reference to Production Examples of the components (A) and (B) and Examples using the above components. However, the present invention is not limited to these Examples. is not.

Production Example 1 (8 mol% of hydroxyl groups are tert-
Synthesis of polyhydroxystyrene substituted with butoxycarbonyloxy group) 120 g of polyhydroxystyrene having a weight average molecular weight of 20,000 was dissolved in 680 g of N, N-dimethylacetamide, and di-tert-butyl-di-butyl was added to the solution. After adding 17.4 g of carbonate and stirring to completely dissolve, 59 g of triethylamine is added to the mixture while stirring.
It was added dropwise over a period of minutes. After completion of the dropwise addition, the mixture was stirred for about 3 hours. Next, a 20-fold amount of pure water was added to the obtained solution, and the mixture was stirred to precipitate polyhydroxystyrene in which a hydroxyl group was substituted with a tert-butoxycarbonyloxy group. The precipitate was washed, dehydrated, and dried to obtain 125 g of polyhydroxystyrene in which 8 mol% of hydroxyl groups were substituted with tert-butoxycarbonyloxy groups.

Production Example 2 (35 mol% of hydroxyl groups is tert
-Synthesis of polyhydroxystyrene substituted with butoxycarbonyloxy group) Production Example 1 was the same as in Production Example 1, except that the amount of di-tert-butyl-di-carbonate was changed to 76.5 g.
145 g of polyhydroxystyrene in which 35 mol% of hydroxyl groups were substituted with tert-butoxycarbonyloxy groups was obtained in the same manner as in Example 1.

Production Example 3 (39 mol% of hydroxyl groups are tert
-Synthesis of polyhydroxystyrene substituted with butoxycarbonyloxy group) Production Example 1 was the same as in Production Example 1, except that the amount of di-tert-butyl-di-carbonate was changed to 85.0 g.
In the same manner as in the above, 150 g of polyhydroxystyrene in which 39 mol% of hydroxyl groups were substituted with tert-butoxycarbonyloxy groups was obtained.

Production Example 4 (70 mol% of hydroxyl groups was tert
-Synthesis of polyhydroxystyrene substituted with butoxycarbonyloxy group) The same procedure as in Production Example 1 was conducted except that the amount of di-tert-butyl-di-carbonate was changed to 153 g. 180 g of polyhydroxystyrene in which mol% was substituted by tert-butoxycarbonyloxy group was obtained.

Production Example 5 (Synthesis of polyhydroxystyrene in which 35 mol% of hydroxyl groups were substituted by ethoxyethoxy groups) 120 g of polyhydroxystyrene having a weight average molecular weight of 20,000 was dissolved in 680 g of N, N-dimethylacetamide. 37.2 g of 1-chloro-1-ethoxyethane was added to the solution, and the mixture was completely dissolved by stirring, and then, with stirring, 78.8 g of triethylamine was added dropwise over about 30 minutes. After completion of the dropwise addition, the mixture was stirred for about 3 hours. Next, a 20-fold amount of pure water was added to the obtained solution, and the mixture was stirred to obtain 130 g of polyhydroxystyrene in which a hydroxyl group was substituted with a 1-ethoxyethoxy group.

Production Example 6 (8 mol% of hydroxyl groups are methoxy-
Synthesis of polyhydroxystyrene substituted with n-propyloxy group) 120 g of polyhydroxystyrene having a weight average molecular weight of 20,000 was dissolved in 680 g of N, N-dimethylacetamide, and 1-chloro-1-methoxy was added to this solution. After adding 8.6 g of propane and stirring to completely dissolve, 78.8 g of triethylamine while stirring.
Was added dropwise over about 30 minutes. After completion of the dropwise addition, the mixture was stirred for about 3 hours. Then, 20 to the resulting solution
Add twice the volume of pure water and stir to make the hydroxyl group 1-methoxy-
Polyhydroxystyrene substituted with an n-propyloxy group was precipitated. The precipitate was washed, dehydrated and dried to obtain 125 g of polyhydroxystyrene in which 8 mol% of hydroxyl groups were substituted by 1-methoxy-n-propyloxy groups .

Production Example 7 (Synthesis of polyhydroxystyrene in which 39 mol% of hydroxyl groups were substituted with methoxy-n-propyloxy group) In Production Example 6, the amount of 1-chloro-1-methoxypropane added was 42.3 g. Polyhydroxystyrene 130 in which 39 mol% of hydroxyl groups were substituted with 1-methoxy-n-propyloxy group in the same manner as in Production Example 6 except that
g was obtained.

Production Example 8 (Synthesis of polyhydroxystyrene in which 70 mol% of hydroxyl groups were substituted with methoxy-n-propyloxy group) In Production Example 6, the amount of 1-chloro-1-methoxypropane was changed to 75.6 g. In the same manner as in Production Example 6, except that the polyhydroxystyrene 150 was substituted with 1-methoxy-n-propyloxy group.
g was obtained.

Example 1 1.48 g of polyhydroxystyrene in which 35 mol% of the hydroxyl groups obtained in Preparation Example 2 were substituted with tert-butoxycarbonyloxy groups and 35% of the hydroxyl groups obtained in Preparation Example 5
After dissolving 1.48 g of polyhydroxystyrene in which mol% has been substituted with ethoxyethoxy groups in 16.8 g of propylene glycol monomethyl ether acetate, 0.148 g of bis (cyclohexylsulfonyl) diazomethane is dissolved.
g and benzophenone were further added and dissolved by adding 0.093 g, and a solution obtained by filtration with a 0.2 μm membrane filter was prepared as a coating solution for a positive resist.

The prepared coating solution was coated on a 6-inch silicon wafer using a spinner and dried on a hot plate at 90 ° C. for 90 seconds to obtain a resist film having a thickness of 0.7 μm. A reduction projection exposure apparatus NSR-2005 is applied to this film.
Using EX8A (manufactured by Nikon Corporation), exposure was performed through a test chart mask, followed by heating at 120 ° C. for 90 seconds, followed by immersion development with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 65 seconds, and washing with water for 30 seconds. After drying to form a resist pattern, 0.21μ
An m-line-and-space pattern was formed, and the cross section of the resist pattern was slightly trapezoidal. In addition, a minimum exposure amount (hereinafter referred to as a minimum exposure amount) in which a large-area resist pattern which can be visually confirmed was patterned and a substrate surface appeared was measured. As a result, it was 7 mJ / cm ² . Further, as a result of examining the heat resistance (temperature at which a flow due to heat occurs) of the formed 0.5 μm line pattern, it was 130 ° C.

Example 2 In the preparation of the coating solution of Example 1, a resist pattern was formed in the same manner as in Example 1 except that benzophenone was omitted. As a result, a line and space pattern of 0.21 μm was formed. Although the cross section of the resist pattern was slightly wavy, it was of a degree that did not cause any trouble, and was a good rectangle. Also, the minimum exposure was measured, and as a result, was 6 mJ / cm ² . Further, as a result of examining the heat resistance of the formed 0.5 μm line space pattern, it was 130 ° C.

Comparative Example 1 After dissolving 2.96 g of polyhydroxystyrene in which 35 mol% of the hydroxyl groups obtained in Production Example 2 were substituted with tert-butoxycarbonyloxy group in 16.8 g of propylene glycol monomethyl ether acetate, (Cyclohexylsulfonyl) diazomethane 0.148
g and benzophenone were further added and dissolved by adding 0.093 g, and a solution obtained by filtration with a 0.2 μm membrane filter was prepared as a coating solution for a positive resist.

A resist pattern was formed in the same manner as in Example 1 using the prepared coating solution.
The 28 μm line-and-space pattern was the limit, and the resist pattern cross section was poor with a tail. In addition, as a result of measuring the minimum exposure, 35
mJ / cm ² . As a result of examining the heat resistance of the formed 0.5 μm line space pattern,
° C.

Comparative Example 2 2.96 g of polyhydroxystyrene in which 35 mol% of the hydroxyl groups obtained in Production Example 5 were substituted with ethoxyethoxy groups
Was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, and 0.148 g of bis (cyclohexylsulfonyl) diazomethane and 0.093 g of benzophenone were further added and dissolved.
A solution filtered through a 2 μm membrane filter was prepared as a coating solution for a positive resist.

A resist pattern was formed by the same operation as in Example 1 using the prepared coating solution.
The limit was a line and space pattern of 25 μm, and the cross section of the resist pattern was an inverted triangular defect. Also, as a result of measuring the minimum exposure, 7 m
J / cm ² . Further, the heat resistance of the formed 0.5 μm line space pattern was examined.
Met.

Example 3 The hydroxyl group 3 obtained in Production Example 3
9% is substituted with a tert-butoxycarbonyloxy group.
Polyhydroxystyrene 1.05g and hydroxyl groups obtained in Production Example 7 39% polyhydroxystyrene 1.95g propylene glycol substituted with methoxy -n- propyl group monomethyl ether acetate 1
After dissolving in 6.8 g, 0.21 g of bis (cyclohexylsulfonyl) diazomethane and 0.009 g of o-nitrobenzoic acid were further added, and the resulting solution was filtered through a 0.2 μm membrane filter. It was prepared as a resist coating solution.

The prepared coating solution was coated on a 6-inch silicon wafer using a spinner, and dried on a hot plate at 90 ° C. for 90 seconds to obtain a resist film having a thickness of 0.7 μm. A reduction projection exposure apparatus NSR-2005 is applied to this film.
Using EX8A (manufactured by Nikon Corporation), exposure was performed through a test chart mask, followed by heating at 110 ° C. for 90 seconds, followed by paddle development with a 2.38% by weight aqueous solution of tetramethylammonium hydroxide for 65 seconds and washing with water for 30 seconds. ,
After drying to form a resist pattern, 0.22
A μm line and space pattern was formed. The cross section of the resist pattern was a little wavy, but of no problem, and was a good rectangle. Also, as a result of measuring the minimum exposure amount, 15 mJ / cm
^{Was 2} . Further, as a result of examining the heat resistance of the formed 0.5 μm line pattern, it was 130 ° C.

Example 4 The procedure of Example 3 was repeated, except that o-nitrobenzoic acid was replaced by SAX (manufactured by Mitsui Toatsu Chemicals) and that 0.128 g of benzophenone was added in the preparation of the coating solution of Example 3. When the resist characteristics were evaluated by the above operation, 0.2
A line and space pattern of 2 μm was formed, and the cross section of the resist pattern was rectangular and excellent without being affected by standing waves. The minimum exposure is 13 mJ / c
m ² . Further, as a result of examining the heat resistance of the formed 0.5 μm line space pattern, it was 130 ° C.

Example 5 The procedure of Example 3 was repeated except that o-nitrobenzoic acid was replaced by salicylic acid, the amount of addition was replaced by 0.003 g, and 0.128 g of benzophenone was added. A coating solution was prepared in the same manner as in No. 3.

Next, when the resist characteristics were evaluated in the same manner as in Example 3, a line-and-space pattern of 0.22 μm was formed. There was no influence of the wave and the shape was good, close to a rectangle. The minimum exposure was 7 mJ / cm ² . 0.5μ further formed
As a result of examining the heat resistance of the m line space pattern, 1
30 ° C.

Comparative Example 3 The hydroxyl group 8 obtained in Production Example 1
1.05 g of polyhydroxystyrene substituted with a tert-butoxycarbonyloxy group in mol % and polyhydroxystyrene 1 in which 8 mol % of a hydroxyl group obtained in Production Example 6 was substituted with a 1 -methoxy-n-propyloxy group .9
5 g was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, and 0.21 g of bis (cyclohexylsulfonyl) diazomethane, 0.009 g of o-nitrobenzoic acid, and 0.128 g of benzophenone were further added and dissolved. Was filtered through a 0.2 μm membrane filter to prepare a coating solution for a positive resist.

When the same coating properties were evaluated for the resist properties as in Example 3, no resist pattern was obtained and the evaluation was impossible.

Comparative Example 4 The hydroxyl group 7 obtained in Production Example 4
Production Example 8: 1.05 g of polyhydroxystyrene having 0 mol % substituted with a tert-butoxycarbonyloxy group
After dissolving 1.95 g of polyhydroxystyrene in which 70 mol % of the hydroxyl groups obtained in 1) were substituted with 1-methoxy-n-propyloxy group in 16.8 g of propylene glycol monomethyl ether acetate, bis (cyclohexylsulfonyl) diazomethane 0 was dissolved. .21 g, SAX
(0.009 g of Mitsui Toatsu Chemical Co., Ltd.) 0.128 g of benzophenone was further added, and the resulting solution was filtered through a 0.2 μm membrane filter to prepare a coating solution for a positive resist.

When the resist properties of the coating solution were evaluated in the same manner as in Example 3, the line-and-space pattern of 0.3 μm was the limit, and the resist pattern had a T-shaped cross section and was poor. Was. Also,
The minimum exposure was 20 mJ / cm ² . Further, as a result of examining the heat resistance of the formed 0.5 μm line space pattern, it was 130 ° C.

Comparative Example 5 8 of the hydroxyl group obtained in Production Example 1
1.05 g of polyhydroxystyrene in which mol % was substituted with tert-butoxycarbonyloxy group and 1.95 polyhydroxystyrene in which 70 mol % of the hydroxyl group obtained in Production Example 8 were substituted with 1-methoxy-n-propyloxy group
g, dissolved in 16.8 g of propylene glycol monomethyl ether acetate, 0.21 g of bis (cyclohexylsulfonyl) diazomethane, 0.001 g of phthalic acid
9 g and 0.128 g of benzophenone were further added, and the resulting solution was filtered through a 0.2 μm membrane filter to prepare a positive resist coating solution.

When the resist properties of the above coating solution were evaluated in the same manner as in Example 3, the line-and-space pattern of 0.3 μm was the limit. Was something. The minimum exposure was 10 mJ / cm ² . Further, as a result of examining the heat resistance of the formed 0.5 μm line space pattern, it was 130 ° C.

[0055]

The positive resist composition of the present invention is of the chemically amplified type and can form a resist pattern having high sensitivity, high resolution, good heat resistance and good cross-sectional shape.
-It is suitable as a resist for UV and excimer lasers, and can be used particularly effectively for microfabrication in the manufacturing process of VLSI.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yohichi Sakai 150 Nakamaruko, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Tokyo Oka Kogyo Co., Ltd. (72) Inventor Kazumi Sato 150 Nakamaruko, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Tokyo Oka Kogyo (72) Inventor Toshimasa Nakayama 150 Nakamaruko, Nakahara-ku, Kawasaki-shi, Kanagawa Tokyo Oka Kogyo Co., Ltd. (56) References JP-A-6-199770 (JP, A) JP-A-4-215662 (JP) JP-A-5-194472 (JP, A) JP-A-6-83058 (JP, A) JP-A-5-181279 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB Name) G03F 7/00-7/42 H01L 21/027

Claims (5)

(57) [Claims] 1. A positive resist composition comprising a resin component and a compound capable of generating an acid upon irradiation with radiation, wherein the resin component comprises (A) 10 to 60 mol% of tert-hydroxyl groups.
The polyhydroxystyrene substituted with -butoxycarbonyloxy group and (B) 10 to 60 mol% of the hydroxyl group are represented by the general formula 1 (Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is a methyl group or an ethyl group, and R ³ is a lower alkyl group). A positive resist composition comprising: 2. The positive resist composition according to claim 1, wherein the compound generating an acid upon irradiation with radiation is bissulfonyldiazomethane. 3. The resin component (A) has a mixing ratio of 10 to 7
2. The positive resist composition according to claim 1, wherein the amount is 0% by weight and the component (B) is 30 to 90% by weight. 4. The positive resist composition according to claim 1, wherein the amount of the compound that generates an acid upon irradiation with radiation is 1 to 20 parts by weight based on 100 parts by weight of the resin component. 5. The positive resist composition according to claim 1, wherein the light absorbing agent is contained in an amount not exceeding 30% by weight based on the total amount of the resin component and the compound capable of generating an acid upon irradiation with radiation. Stuff.