JPH05289322A - Pattern forming material and method for forming pattern using the same - Google Patents

Abstract

PURPOSE:To form a pattern having steps by exposing a pattern forming material which drastically changes dissolving rate at some developing time, through a mask having a pattern different in transmissivity. CONSTITUTION:The dissolving rate after exposing and baking the pattern forming material containing an alkali soluble phenolic resin, a dissolving restrainer, an acid precursor and an acid capturing agent, is drastically changed at some developing time. The pattern having steps is formed by baking and developing after exposing the material through the mask having the pattern different in transmissivity. Thus, the pattern having steps and high resolution is formed by the exposing method by the use of a short wavelength light exposure device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for forming a semiconductor element or a desired organic material pattern having different heights and a method for forming the pattern.

[0002]

2. Description of the Related Art The microfabrication technique used for manufacturing semiconductor devices such as LSI and VLSI can be applied to other pattern forming techniques. As a technique for forming patterns with different heights or steps, using a positive photoresist made of diazonaphthoquinone and novolac resin, an acid-curable negative chemical amplification resist, and exposing through a mask having patterns of different transmittances. The method is reported by Feely (SPI E, 631, 48, 1986).

[0003]

When a positive photoresist composed of diazonaphthoquinone and a novolac resin or an acid-curable negative chemical amplification resist is used, the dew portion of the resist, the intermediate dew having a transmittance of 30% to 70%. A stepped pattern is formed by utilizing the difference in developing speed between the rear part and the unexposed rear part. This means that there is a large change in the film thickness in the intermediate exposure region due to the difference in development time. An object of the present invention is to provide a pattern forming material and a pattern forming method that cause little change in film thickness.

[0004]

[Means for Solving the Problems] The above-mentioned object is to form a coating film of a pattern-forming material comprising an alkali-soluble phenol resin, a dissolution inhibitor, an acid precursor and an acid scavenger, and to provide a mask having patterns having different transmittances. It is achieved by a pattern forming method of performing baking and development after exposure through.

The pattern-forming material of the present invention is at least one kind of polymer selected from the group consisting of novolac resins, halogenated novolac resins, polyvinylphenols, and polyvinylphenol halides as the phenolic resin soluble in an alkaline aqueous solution.

As the acid precursor, alkyl and aryl sulfonic acid esters can be used. For example, tri (methanesulfonyloxy) benzene, tri (ethanesulfonyloxy) benzene, tri (propanesulfonyloxy) benzene, tri (butanesulfonyloxy) benzene, tri (benzenesulfonyloxy) benzene, tri (toluenesulfonyloxy) benzene, Examples include tri (naphthalenesulfonyloxy) benzene. An onium salt can also be used as the acid precursor. For example, there are triphenylsulfonyl triflate, diphenyliodonium triflate, bis (pt-butylphenyl) iodonium triflate, and the like.

As the dissolution inhibitor, a compound having a phenolic hydroxyl group, a compound obtained by protecting the phenolic hydroxyl group of a polymer with a tetrahydropyranyl group or a t-butoxycarbonyl group, and a polymer can be used. For example, novolac resin, halogenated novolac resin, polyvinylphenol, a polymer obtained by protecting the phenolic hydroxyl group of a polyvinylphenol halide with a tetrahydropyranyl group,
A compound obtained by protecting bisphenol A, 1,1,1-tris (4-hydroxyphenyl) ethane with a tetrahydropyranyl group or a t-butoxycarbonyl group is used.

An amine is used as the acid scavenger. For example,
Imidazole, benzimidazole, phenylimidazole, aminophenol, etc. are used. It is desirable that this acid scavenger does not fly off the resist film during baking after exposure.

[0009]

[Function] Alkali-soluble phenol resin, dissolution inhibitor,
When the dissolution rate of the pattern forming material containing the acid precursor and the acid scavenger after exposure and baking was examined, it was found that the dissolution rate of the resist was extremely decreased at a certain film thickness at a certain exposure amount. This is because the acid concentration generated by exposure is distributed in the film thickness direction (more in the upper part of the resist and less in the vicinity of the substrate), and an acid having a certain concentration or less is trapped by the amine which is an acid scavenger. In the following, it is considered that the acid-catalyzed reaction is suppressed. It is considered that the dissolution rate decreased because the amount of acid-catalyzed reaction product was less than a certain film thickness. On the other hand, when the pattern forming material containing no acid scavenger is used, the dissolution rate does not extremely decrease at a certain film thickness, and the resist film is developed. Thus, by adding amine, which is an acid scavenger, to the pattern forming material, the dissolution rate in the film thickness direction can be controlled, and after this material is exposed through a mask having patterns having different transmittances, baking is performed. By developing, it is possible to form a stepped pattern, which facilitates control.

[0010]

【Example】

<Example 1> 100 parts by weight of m, p-cresol novolac resin (molecular weight of about 10,000), 12.9 parts by weight of a dissolution inhibitor obtained by protecting polyvinylphenol with a tetrahydropyranyl group, 1,2,3-tri (methane) Sulfonyloxy) benzene (4.7 parts by weight) and benzimidazole (1 part by weight) were dissolved in methoxyethyl acetate (354 parts by weight), and this was filtered using a Teflon membrane filter having a pore size of 0.2 μm to obtain a resist solution. A resist solution of this composition was dropped on a silicon substrate, spin-coated, and baked at 120 ° C. for 1 minute to form a resist film of 1 μm. 600WHg-X
The light from the e-lamp is passed through a 248 nm bandpass filter so that 248 nm monochromatic light passes through 68 mJ / cm ²
The photoresist film on the wafer was irradiated. After the irradiation, the photoresist was baked at 80 ° C. for 2 minutes, and the change in film thickness in the developing solution was examined by a method using interference of He—Ne laser.

As a result, as shown in FIG. 1, the developing speed of the resist changes greatly at 50 seconds and becomes slow.
The resist film has a transmittance of about 100%, 50%,
Irradiation was carried out at 138 mJ / cm ² through a mask containing 0% pattern. After irradiation, the photoresist was baked at 80 ° C. for 2 minutes and developed with a 2.38% tetramethylammonium hydroxide aqueous solution for 80 seconds. As a result, the residual film of the pattern having a transmittance of 50% was 480 nm, and a good pattern having a step was obtained.

Example 2 A resist film was coated on a silicon wafer in the same manner as in Example 1 except that 5 parts by weight of 5-amino-2-naphthol was used as an acid scavenger, and the transmittance was about 10%.
10 through a mask containing 0%, 50%, 0% pattern
Irradiation was carried out at 9 mJ / cm ² . When baked at 80 ° C. for 2 minutes and developed with a 2.38% tetramethylammonium hydroxide aqueous solution, the residual film of a pattern having a transmittance of 50% was 500 nm, and a good pattern having a step could be formed.

<Example 3> 4-phenylimidazole 1
A resist film was applied on a silicon wafer in the same manner as in Example 1 except that parts by weight were used as an acid scavenger, and the transmittance was about 10
48 via a mask containing 0%, 50% and 0% patterns
It was irradiated with mJ / cm ² . When baked at 80 ° C. for 2 minutes and developed with a 2.38% tetramethylammonium hydroxide aqueous solution, the residual film of a pattern having a transmittance of 50% was 512 nm, and a good pattern having a step could be formed.

Example 4 A resist film was coated on a silicon wafer in the same manner as in Example 1 except that 1 part by weight of imidazole was used as an acid scavenger, and the transmittance was about 100% and 50%.
205mJ / cm through a mask containing%, 0% pattern
Irradiated ² times. When baked at 80 ° C. for 2 minutes and developed with a 2.38% tetramethylammonium hydroxide aqueous solution, the residual film of a pattern having a transmittance of 50% was 480 nm, and a good pattern having a step could be formed.

[0015]

According to the pattern forming method of the present invention, it is possible to form a stepped pattern in which the residual film of the resist has an initial film thickness and a half of the initial film thickness. According to the pattern forming method using this pattern forming material, Kr
A high-resolution pattern can be formed by an exposure method using an F excimer laser reduction projection exposure apparatus. Therefore,
By the pattern forming method according to the present invention, it is possible to form a step pattern of an arbitrary organic material with high resolution.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing a relationship between a remaining film thickness of a pattern forming material according to the present invention and a developing time.

[Explanation of symbols]

1 ... 68 mJ / cm ² exposed resist film, 2 ... 140 m
J / cm ² exposed resist film.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G03F 7/20 521 7818-2H 7/30 7124-2H H01L 21/027

Claims (8)

[Claims] 1. A coating film of a chemically amplified resist composition comprising an alkali-soluble phenol resin, a dissolution inhibitor, an acid precursor and an acid scavenger, wherein the dissolution rate changes in the middle of the coating film. Pattern forming material. 2. The pattern forming material according to claim 1, wherein the acid precursor is an ester of a compound having two or more phenolic hydroxyl groups and an alkylsulfonic acid. 3. The compound according to claim 1, wherein the dissolution inhibitor is a compound having a phenolic hydroxyl group, a compound in which a phenolic hydroxyl group of a polymer is protected by a tetrahydropyranyl group or a t-butoxycarbonyl group, and at least one type of polymer. A pattern forming material that is a selected dissolution inhibitor. 4. The pattern forming material according to claim 1, wherein the acid scavenger is a compound selected from at least one kind of amine. 5. A step of forming a coating film of a pattern forming material comprising an alkali-soluble phenol resin, a dissolution inhibitor, an acid precursor and an acid scavenger, and a pattern having a different transmittance to the coating film by using active actinic radiation. Forming a desired pattern latent image through a mask having a pattern, a step of accelerating a reaction that changes the solubility of the pattern latent image forming part in an alkaline aqueous solution, and developing the predetermined pattern using the alkaline aqueous solution as a developing solution. A pattern forming method comprising forming a pattern having a step in the step of forming a pattern. 6. The pattern forming method according to claim 1, wherein the acid precursor is an ester of a compound having two or more phenolic hydroxyl groups and an alkylsulfonic acid. 7. The compound according to claim 1, wherein the dissolution inhibitor is a compound having a phenolic hydroxyl group, a compound in which a phenolic hydroxyl group of a polymer is protected with a tetrahydropyranyl group or a t-butoxycarbonyl group, and at least one type of polymer. A pattern formation method that is a selected dissolution inhibitor. 8. The pattern forming method according to claim 1, wherein the acid scavenger is a compound selected from at least one kind of amine.