JPH11222507A - Production of polyhydroxystyrene derivative - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a polyhydroxystyrene derivative useful as a resin component for a chemically amplified positive resist composition which can form a resist pattern being highly sensitive to deep UV or excimer lasers, having high resolution and a good sectional shape and is excellent in heat resistance. SOLUTION: A polyhydroxystyrene is reacted with a compound represented by formula I(wherein R<1> is hydrogen or methyl; R<2> is methyl or ethyl; R<3> is a lower alkyl; and X is Cl) to replace the hydroxyl groups of the polyhydroxystyrene by residues represented by the formula (wherein R<1> is hydrogen or methyl; R<2> is methyl or ethyl; and R<3> is a lower alkyl).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a polyhydroxystyrene derivative, and more particularly, to a method for producing a polyhydroxystyrene derivative useful as a resin component of a chemically amplified positive photoresist composition.

[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 generally comprises an acid generator and a resin component whose solubility in an aqueous alkali solution increases due to the action of the generated acid. Have been. On the other hand, a negative resist is composed of an acid generator, a crosslinking agent, and an alkali-soluble resin component.

[0006] A resist using polyhydroxystyrene as a resin component in the above chemically amplified positive resist has been proposed in Japanese Patent Publication No. 2-27660. The chemically amplified positive resist described in the above publication is a resist using a resin component in which a hydroxyl group of polyvinyl phenol is substituted with a tert-butoxycarbonyloxy group and an onium salt of an acid generator, and is a deep-UV or excimer laser. Not only the light transmittance to light is not always enough, sensitivity,
The resolution, heat resistance, and cross-sectional shape of the resist pattern were not sufficiently satisfactory, and the resist was not practically satisfactory.

[0007]

In view of the current situation,
The present inventors have conducted intensive studies on the application of polyhydroxystyrene having low light absorption to a chemically amplified positive resist, and as a result, caused a substitution reaction between polyhydroxystyrene and a specific compound, which was chemically amplified. By using a positive resist as a resin component, it is possible to form a resist pattern having excellent light transmittance to deep-UV or excimer laser light, high sensitivity, high resolution, excellent heat resistance, and a good cross-sectional shape. The inventors have found that a chemically amplified positive resist composition can be obtained, and have completed the present invention. Ie

An object of the present invention is to provide a method for producing a novel polyhydroxystyrene derivative.

Further, the present invention is directed to a chemical amplification method capable of forming a resist pattern having excellent light transmittance to deep-UV and excimer laser light, high sensitivity, high resolution, excellent heat resistance and a good cross-sectional shape. It is an object of the present invention to provide a method for producing a polyhydroxystyrene derivative useful as a resin component of a positive resist composition of a negative type.

[0010]

SUMMARY OF THE INVENTION The present invention, which achieves the above object, comprises a polyhydroxystyrene having the general formula

[0011]

Embedded image (Wherein, R1 is a hydrogen atom or a methyl group, R2 is a methyl or ethyl group, R3 is a lower alkyl group, and X is Cl.) To react with a compound represented by the general formula 4

[0012]

Embedded image (In the formula, R1 represents a hydrogen atom or a methyl group, R2 represents a methyl group or an ethyl group, and R3 represents a lower alkyl group.)
A method for producing a polyhydroxystyrene derivative characterized by substituting with a residue represented by the formula:

As described above, the production method of the present invention uses polyhydroxystyrene and general formula 5

[0014]

Embedded image (Wherein, R1 is a hydrogen atom or a methyl group, R2 is a methyl or ethyl group, R3 is a lower alkyl group, and X is Cl.) A compound represented by the following formula is dissolved in an organic solvent such as N, N-dimethylacetamide. And a method for producing a polyhydroxystyrene derivative obtained by performing a substitution reaction in the presence of a known catalyst such as triethylamine, wherein the obtained polyhydroxystyrene derivative has a hydroxyl group content of 10 to 60 mol%, preferably 20 to 60 mol%. 50 mol% is a general formula 6

[0015]

Embedded image (In the formula, R1 represents a hydrogen atom or a methyl group, R2 represents a methyl group or an ethyl group, and R3 represents a lower alkyl group.)
Is preferably substituted with the residue represented by Specific examples of the compound represented by the general formula 5 include 1-chloro-1-methoxyethane, 1-chloro-1-ethoxyethane, and 1-chloro-1-methoxyethane.
Chloro-1-n-propoxyethane, 1-chloro-1-
Isopropoxyethane, 1-chloro-1-n-butoxyethane, 1-chloro-1-isobutoxyethane, 1-chloro-1- (1,1-dimethylethoxy) -1-methylethane, 1-chloro-1- Methoxy-1-methylethane, 1-chloro-1-ethoxy-1-methylethane, 1
-Chloro-1-n-propoxy-1-methylethane, 1
-Chloro-1-isobutoxy-1-methylethane, 1-
Chloro-1-methoxy-n-propane, 1-chloro-1
-Ethoxy-n-propane. The polyhydroxystyrene derivative obtained by the substitution reaction (hereinafter referred to as (A)
The substituent is a residue of 1-methoxyethoxy group, 1-ethoxyethoxy group, 1-n-propoxyethoxy group, 1-isopropoxyethoxy group, 1-n-butoxyethoxy group, 1-isobutoxyethoxy. Group, 1-
(1,1-dimethylethoxy) -1-methylethoxy group, 1-methoxy-1-methylethoxy group, 1-ethoxy-1-methylethoxy group, 1-n-propoxy-1-
Preferred are a methylethoxy group, a 1-isobutoxy-1-methylethoxy group, a 1-methoxy-n-propoxy group, a 1-ethoxy-n-propoxy group and the like. In particular, a polyhydroxystyrene derivative having a 1-ethoxyethoxy group and a 1-methoxy-n-propoxy group as a residue is preferable because it improves the sensitivity and resolution of a chemically amplified positive resist composition in a well-balanced manner. If the substitution ratio is less than 10 mol%, a pattern having an excellent shape cannot be obtained. If the substitution ratio exceeds 60 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 polyhydroxystyrene derivative obtained by the production method of the present invention is preferably 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. In using this polyhydroxystyrene derivative as a resin component of a chemically amplified positive resist composition, it is preferable to mix it with a polyhydroxystyrene substituted with a tert-butoxycarbonyloxy group (hereinafter, referred to as a component (B)). The component (B) is obtained by subjecting the hydroxyl group of polyhydroxystyrene to te-substitution with, for example, di-tert-butyl-di-carbonate according to a known substitution reaction.
substituted with an rt-butoxycarbonyloxy group,
The substitution rate is 10 to 60 mol%, preferably 20 to 50 mol%.
Molar% 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.

When the mixture of the above components (A) and (B) is used as the resin component of a chemically amplified positive resist composition, the content of component (A) is 30 to 90% by weight, preferably 50 to 80%. %, The mixing ratio of the component (B) is in the range of 10 to 70% by weight, preferably 20 to 50% by weight. When the resin component in the above range is used, the acid generated from the acid generator decomposes the tert-butoxycarbonyloxy group and the residue represented by the general formula 6, and these dissolve the resin component and the t
The dissolution inhibiting ability of the ert-butoxycarbonyloxy group is appropriately balanced, and high sensitivity and high resolution can be achieved. If the mixing ratio of the resin component deviates from the above range, these characteristics cannot be obtained.

The chemically amplified positive resist composition comprises, as resin components, the polyhydroxystyrene derivative obtained by the production method of the present invention and an acid generator as basic components, and if necessary, a light absorbing agent and an organic carboxylic acid. It is preferable to use an acid compound or the like dissolved in a solvent. Examples of the solvent 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 monoacetate monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl Polyhydric alcohols such as ethers and derivatives thereof; cyclic ethers such as dioxane; and methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethoxy Esters such as ethyl propionate can be mentioned. These may be used alone or as a mixture of two or more.

As a method of using the chemically amplified positive resist composition containing the polyhydroxystyrene derivative obtained as a resin component as a resin component, a conventional photoresist pattern forming method of the photoresist technique is used. As an example, first, on a support such as a silicon wafer, a resin component, an acid generator, a light-absorbing agent and an organic carboxylic acid compound which are optionally added, and various additives which are optionally added are dissolved in the above-mentioned solvent. The resulting solution 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 Development processing is performed using a weakly alkaline aqueous solution such as a 10% by weight aqueous solution of tetramethylammonium hydroxide. With this forming method, an image faithful to the mask pattern can be obtained.

[0020]

Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the present invention.

Example 1 120 g of polyhydroxystyrene having a weight-average molecular weight of 20,000 was dissolved in 680 g of N, N-dimethylacetamide, and 37.2 g of 1-chloro-1-ethoxyethane was added to the solution and stirred. After complete dissolution, 78.8 g of triethylamine was added dropwise with stirring 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 35 mol% of hydroxyl groups were substituted with 1-ethoxyethoxy groups.
I got

Example 2 120 g of polyhydroxystyrene having a weight average molecular weight of 20,000 was dissolved in 680 g of N, N-dimethylacetamide, and 42.3 g of 1-chloro-1-methoxypropane was added to the solution and stirred. After complete dissolution,
While 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 precipitate polyhydroxystyrene in which a hydroxyl group was substituted with a 1-methoxy-n-propyloxy group. The precipitate is washed, dehydrated, and dried to obtain 39
130 g of polyhydroxystyrene in which mol% was substituted by 1-methoxy-n-propyloxy group were obtained.

Reference Example 1 1.48 g of polyhydroxystyrene in which 35 mol% of hydroxyl groups were substituted by tert-butoxycarbonyloxy group
And 1.48 of polyhydroxystyrene in which 35 mol% of the hydroxyl groups obtained in Example 1 were substituted with ethoxyethoxy groups.
g 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 with an m membrane filter was prepared as a coating solution for a positive resist.

The prepared coating solution was applied on a 6-inch silicon wafer using a spinner and dried on a hot plate at 90 ° C. for 90 seconds to obtain a 0.7 μm-thick resist film. 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. The minimum exposure amount (hereinafter, referred to as minimum exposure amount) in which a large-area resist pattern that can be visually confirmed was patterned and the substrate surface appeared was measured. As a result, it was 7 mJ / cm2. 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.

Reference Example 2 2.96 g of polyhydroxystyrene in which 35 mol% of hydroxyl groups were substituted by tert-butoxycarbonyloxy 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 3 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 / cm2. As a result of examining the heat resistance of the formed 0.5 μm line space pattern,
° C.

Reference Example 3 1.05 g of polyhydroxystyrene in which 39% of hydroxyl groups were replaced by tert-butoxycarbonyloxy group and polyhydroxystyrene in which 39% of hydroxyl groups obtained in Example 2 were replaced by methoxy-n-propyloxy group 1.95 g of hydroxystyrene
Was dissolved in 16.8 g of propylene glycol monomethyl ether acetate, 0.21 g of bis (cyclohexylsulfonyl) diazomethane and 0.009 g of o-nitrobenzoic acid were further added, and the resulting solution was dissolved in a 0.2 μm membrane filter. To prepare a coating solution for a positive resist.

The prepared coating solution was applied 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
It was 2. Further, as a result of examining the heat resistance of the formed 0.5 μm line pattern, it was 130 ° C.

[0029]

According to the production method of the present invention, a polyhydroxystyrene derivative useful as a resin component of a chemically amplified positive resist composition can be produced. A resist pattern having high sensitivity, high resolution, good heat resistance and good cross-sectional shape can be formed.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yohichi Sakai 150 Nakamurako, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Tokyo Ohka Kogyo Co., Ltd. (72) Kazufumi Sato 150 Nakamaruko, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Tokyo (72) Inventor Toshiaki Nakayama 150 Nakamurako, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Tokyo Ohka Industry Co., Ltd.

Claims (3)

[Claims] (1) Polyhydroxystyrene and a general formula (1) (Wherein, R1 is a hydrogen atom or a methyl group, R2 is a methyl or ethyl group, R3 is a lower alkyl group, and X is Cl.) To form a hydroxyl group of polyhydroxystyrene into a general formula. 2 (In the formula, R1 represents a hydrogen atom or a methyl group, R2 represents a methyl group or an ethyl group, and R3 represents a lower alkyl group.)
A method for producing a polyhydroxystyrene derivative, which comprises substituting with a residue represented by the formula: 2. A polyhydroxystyrene having a hydroxyl group of 10 to 10.
The method for producing a polyhydroxystyrene derivative according to claim 1, wherein 60 mol% is substituted with a residue represented by the general formula (2). 3. The compound represented by the general formula 1 is 1-chloro-1-ethoxyethane or 1-chloro-1-methoxy-n-propane, and the residue represented by the general formula 2 is 1-ethoxy. The method for producing a polyhydroxystyrene derivative according to claim 1, which is an ethoxy group or a 1-methoxy-n-propoxy group.