JPH02170165A - Radiation sensitive composition and pattern forming method using this composition - Google Patents

Abstract

PURPOSE:To enhance the sensitivity and resolution to active radiations of the compsn. and to shorten the time for baking after exposing by using a prescribed compd. which generates an acid by irradiation of radiations and a prescribed phenolic resin. CONSTITUTION:This compsn. consists of the compd. (A) which generates an acid by irradiation of the radiations and the alkali soluble phenolic resin (B) contg. a methoxymethyl group or/and methylol group. After the above-mentioned compsn. is applied on the substrate and is prebaked, patterns are transferred thereto by irradiation of the radiations. The compsn. is then developed with an alkaline developing soln. to obtain the negative type patterns. An onium salt, such as diaryl iodonium salt is usable for the component A and an alkaline soluble high-polymer compd. contg. the unit expressed by the formula is preferably used for the component B. In the formula R denotes H, methyl; n, m denotes 1, 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a composition sensitive to radiation such as ultraviolet rays, electron beams, ion beams, or X-rays, and a pattern forming method using the same. More specifically, the present invention relates to a radiation-sensitive composition suitable for microfabrication and excellent in dry etching resistance, and a batten forming method using the same.

[Conventional technology]

Conventionally, a negative photoresist composition comprising a mixed system of a compound that generates an acid upon radiation irradiation, a compound (crosslinking agent) that undergoes a crosslinking reaction with a polymer by the acid, and a polymer, and a method for forming a negative image, have been disclosed in Japanese Patent Application Laid-Open No. 1983-1999. 16404.5
It is discussed in This photoresist composition can be developed with an aqueous developer, and the resulting image has excellent thermal stability.

[Problem to be solved by the invention]

In the above-mentioned prior art, a low molecular weight compound is used as a compound that crosslinks the polymer with vinegar. This system requires a post-baking step of 15 to 30 minutes after exposure, which poses a problem, for example, in causing a significant drop in throughput in the mass production process of semiconductor devices.

An object of the present invention is to provide a resist composition that can shorten the post-baking process after exposure, has high resolution and high sensitivity to electron beams, X-rays, or short wavelength ultraviolet rays, and a method for forming battens using the resist composition. It is in.

[Means to solve the problem]

The above-mentioned object is (1) a radiation-sensitive composition characterized by containing a compound that generates an acid upon radiation irradiation, and an alkali-soluble phenolic resin having a methoxymethyl group, a methylol group, or both. (2) A compound that generates an acid when irradiated with radiation, and a structure corresponding to the formula % "In the formula, n and m represent an integer of 1 to 2, and R represents a hydrogen atom or a methyl group." 1. A radiation-sensitive composition comprising an alkali-soluble polymer containing at least a unit.

(3) Applying the radiation-sensitive composition described in item 2 (1) on the substrate to form a resist film, prebaking to remove the coating solvent, and transferring the pattern to the resist layer by radiation irradiation. A pattern forming method comprising the following steps: a step of baking after irradiation with radiation, and a step of developing with an alkaline developer to obtain a negative pattern. (4) A step of applying the radiation-sensitive composition described in (2) above on a substrate to form a resist I/film, a prebaking step to remove the coating solvent, and a pattern transfer to the resist layer by radiation irradiation. This is achieved by a pattern forming method characterized by comprising a step of baking after irradiation with radiation, and a step of developing with an alkaline developer to obtain a negative pattern.

The radiation-sensitive composition is applied onto a substrate to form a thin film, baked under controlled conditions, irradiated with radiation in a pattern, and then post-baked under controlled conditions. Let's do it. In the radiation irradiated area, the polymer undergoes a crosslinking reaction due to the generated acid, and becomes insoluble in an alkaline developer.

In the present invention, all compounds that generate strong acids upon irradiation with radiation can be used. However, onium salts such as aryldiazonium salts, triarylsulfonium salts, and diaryliodonium salts are useful as acid generators. Counter anions of onium salts include lead metal halides such as tetrafluoroborate, hexafluoroantimonate, and hexafluoroarsenate, but for use in semiconductor device manufacturing, trifluoromethanesulfonic acid, trifluoroacetic acid,
It is preferable to use a salt such as toluenesulfonic acid. In addition, halogenated organic compounds such as tris(2,3-dibromopropyl)isocyanurate and the like can also be used. The present invention is not limited to onium salts and halogenated organic compounds having the counteranions mentioned above, but can be applied to a wide range of compounds that generate acids when exposed to radiation. The compounds described can be used. The amount of the compound that generates acid upon irradiation with radiation used in the present invention is
A preferable range is 0.1 to 80% by weight based on fM fat). A particularly preferred concentration range is from 0.5 to 50% by weight.

If it is less than 0.3% by weight, the acid catalytic effect of the crosslinking reaction is small;
Long-term heating is required to cure. Also, 8
If it exceeds 0% by weight, the properties of a coating film tend to deteriorate, so the above range is desirable.

The polymer used in the present invention is an alkali-soluble polymer having a hydroxymethyl group, a methoxymethyl group, or both at the same time, and preferably has a phenolic hydroxyl group. In addition, polymerizable monomers having hydroxymethyl group or methoxymethyl group or both at the same time, vinyl phenol, styrene, methacrylate esters such as methyl methacrylate, acrylic acid esters such as methyl acrylate, maleic anhydride, methacrylic acid It is also possible to use copolymers with monomers such as acrylic acid and acrylic acid. Preferably, these copolymers also have a phenolic hydroxyl group.

Furthermore, in the present invention, the alkali-soluble polymer or copolymer can be used alone or in combination with other alkali-soluble polymers such as polyvinylphenol, halogen-substituted polyvinylphenol, or novolak resin. .

In the composition of the present invention, the proportion of the structural moiety having a hydroxymethyl group or a methoxymethyl group, or both, is preferably in the range of 1 to 100 parts by weight, and preferably 10 to 100 parts by weight, based on 100 parts by weight of the polymer. It is more preferable that Less than 1 part by weight is less effective.

[Effect]

When an alkali-soluble polymer having a hydroxymethyl group, a methoxymethyl group, or both at the same time is attacked by an acid generated by radiation irradiation, the alkali-soluble polymers efficiently undergo a dehydration condensation reaction with each other. In an alkali-soluble polymer containing multiple hydroxymethyl groups or methoxymethyl groups in one molecule, multiple crosslinking reactions occur, resulting in a compound with a very large molecular weight that is easily insoluble in aqueous alkaline solutions.

As a result, the radiation irradiated area loses its solubility and a negative type lump is formed, but the insolubilization efficiency is significantly improved compared to a composition containing a monomeric hydroxymethyl group or methoxymethyl group. Therefore, it is possible to perform post-exposure baking in a short time.

〔Example〕

The contents of the present invention will be explained below using examples.

Example 1 A cyclohexanone solution containing 20 parts by weight of poly(4-hydroxy-3-human oxymethylstyrene) and 1.8 parts by weight of diphenyliodonium trifluoromethanesulfonate was prepared and used as a resist solution. This resist solution was spin-coated onto a silicon wafer at a rotation speed of 300 rpm and baked at 80° C. for 2 minutes to form a resist film with a thickness of 1.0 μm. This resist film was placed in an electron beam lithography system and subjected to electron beam lithography at a dose of 30 kV, 4 μC, and IJ.

After baking at 80°C for 1 minute, it was developed with a 1.0% aqueous solution of tetramethylammonium hydroxide for 30 seconds to obtain a good zero.
．． A line-and-space pattern of 4 μm could be formed.

Example 2 Exactly the same operation was carried out using diphenyliodonium trifluoroacetate in place of diphenyliodonium trifluoromethanesulfonate in Example 1, and the result was 4 μC/d.
A good 0.5 μm pattern was obtained with the irradiation amount of .

Similar results were also obtained using diphenyliodonium-ph luenesulfonate and hexafluoroarsenate.

Example 3 The same operation as in Example 1 was carried out using poly(4-hydroxy-3-methoxymethylstyrene) instead of poly(4-hydroxy-3-hydroxymethylstyrene), and the irradiation dose was 5 μC/d. After exposure, a good 0.5 μm pattern was obtained by baking at 100° C. for 2 minutes.

Example 4 The same operation as in Example 2 was carried out using poly(3,4-dihydroxy-5-hydroxymethylstyrene) instead of poly(4-hydroxy-3-hydroxymethylstyrene). Irradiation amount 30kV4μC/a#, 80 after exposure
C. for 1 minute and development with a 1.0% aqueous solution of tetramethylammonium hydroxide for 30 seconds, a good 0.5 .mu.m line-and-space pattern could be formed.

Example 5 The same operation as in Example 1 was carried out using poly(4-hydroxy-3,5-dihydroxymethylstyrene) instead of poly(4-hydroxy-3-hydroxymethylstyrene). A good 0.5 μm line-anthospice pattern was formed by irradiation dose of 30 kV, 3 μC/cJ, baking at 80° C. for 1 minute after exposure, and development for 30 seconds with a 1.0% aqueous solution of tetramethylammonium hydroxide. I was able to do that.

Example 6 Example 1 was performed using a copolymer of 4-hydroxy-3-hydroxymethylstyrene and vinylphenol (monomer unit ratio 3 near) instead of poly(4-hydroxy-3-hydroxymethylstyrene). A similar operation was performed. Irradiation dose 3QkV5μC/aJ, 1 minute bake at 100°C after exposure, 1.0% tetramethylammonium hydroxide
% aqueous solution for 30 seconds to give a good 0.4μ
It was possible to form a line-and-space pattern of m.

Example 7 Instead of the copolymer of Example 6, 4-hydroxy-3-
Copolymer of hydroxymethylstyrene, vinylphenol and styrene (ratio in 1,000 units: 4:5:1)
The same operation as in Example 1 was performed using . Irradiation amount 30
A high-resolution negative pattern could be formed by kV 4 μC/cJ, baking at 100° C. for 1.5 minutes after exposure, and development for 40 seconds with a 1.5% aqueous solution of tetramethylammonium hydroxide.

Example 8 Poly(4-hydroxy-
The same operation as in Example 1 was carried out using a mixture of (3-hydroxymethylstyrene) and polyvinylphenol (weight ratio: 4 near). A high-resolution negative pattern could be formed by applying an irradiation dose of 30 kV and 5 μC/al, baking at 90° C. for 1 minute after exposure, and developing for 25 seconds with a 1% aqueous solution of tetramethylammonium hydroxide.

Example 9 Instead of polyvinylphenol in Example 8, rn, p
-Cresol novolac resin (Gunei Chemical PSF2803
), the same operation as in Example 8 was performed. Irradiation amount 3
A high-resolution negative pattern could be formed by baking at 0 kV, 4 μC/ffl, after exposure at 90° C. for 2 minutes, and developing with a 2% aqueous solution of tetramethylammonium hydroxide for 45 seconds.

Example 10 A cyclohexanone solution containing 20 parts by weight of poly(4-hydroxy-3-hydroxymethylstyrene) and 1.8 parts by weight of diphenyliodonium trifluoromethanesulfonate was prepared and used as a resist solution. Example 1
A resist film was formed by processing in the same manner as above. This resist film was exposed to light from a xenon-mercury lamp through a 248 nm interference filter at an exposure dose of 10 mJ/cm 2 . 80 after exposure
C. for 2 minutes and developed with a 1% aqueous solution of tetramethylammonium hydroxide for 30 seconds to form a high-resolution negative pattern.

Example 11 In place of diphenyliodonium trifluoromethanesulfonic acid in Example 10, 4-N.

A resist film was formed in the same manner as in Example 7 using N-dimethylaminobenzenediazonium trifluoromethanesulfonate. This film was irradiated with light (365 nm) from a mercury lamp and exposed in a pattern at an exposure dose of 20 mJ/cm2. After exposure, the film was baked at 80° C. for 2 minutes and developed with a 1% aqueous solution of tetramethylammonium hydroxide for 30 seconds to form a high-resolution negative pattern.

Example 12 The same operation as in Example 8 was carried out except that tris(2,3-dibromopropyl)in cyanurate was used instead of diphenyliodonium trifluoromethanesulfonic acid in Example 11, and a high-resolution negative type was obtained. I was able to form a pattern.

Example 13 A resist film was formed using the resist solution shown in Example 8, and irradiated with light (248 nm) from a xenon-mercury lamp in the same manner as in Example 10 (20 mJ/cm'') - 80°C after exposure. After baking for 2 minutes and developing with a 1% aqueous solution of tetramethylammonium hydroxide for 30 seconds, a high-resolution negative pattern could be formed.

Example 14 A resist film was formed using the resist solution shown in Example 9, and was irradiated with light (248 nm) from a xenon-mercury lamp in the same manner as in Example 10 (20 mJ/cm2).

After exposure, it was baked at 80'C for 2 minutes and developed with a 1% aqueous solution of tetramethylammonium hydroxide for 30 seconds to form a high resolution negative pattern.

Example 15 A high-resolution negative pattern could be obtained by using diphenyliodonium trifluoroacetic acid instead of diphenyliodonium trifluoromethanesulfonic acid in Example 10 and performing the same operation as in Example 9. . Similar effects were also obtained using diphenyliodonium hexafluoroantimonate.

Example 16 Using the resist composition of Example 5, the same operations as in Example 10 were performed. Light from a xenon-mercury lamp (24
8nm) and 20mJ/cm2), 80mJ/cm2) after exposure.
C. for 2 minutes and developed with a 1% aqueous solution of tetramethylammonium hydroxide for 30 seconds to form a high-resolution negative pattern.

Example 17 A resist film was formed using the resist solution shown in Example 1, and synchroton radiation (SOR) light (40 mJ/c
m'), baked at 80° C. for 2 minutes after exposure, and developed with a 1% aqueous solution of tetramethylammonium hydroxide for 30 seconds to form a high-resolution negative pattern.

〔Effect of the invention〕

According to the present invention, it has excellent sensitivity to short wavelength ultraviolet rays, electron beams, A resist composition and a method for forming a batten using the same can be obtained.

Claims (1)

[Scope of Claims] 1. A radiation-sensitive composition comprising a compound that generates an acid upon irradiation with radiation, and an alkali-soluble phenolic resin containing a methoxymethyl group, a methylol group, or both. 2. Compounds that generate acids when irradiated with radiation and general formulas: ▲Mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, n and m represent integers of 1 to 2, and R represents a hydrogen atom or a methyl group. A radiation-sensitive composition comprising an alkali-soluble polymer containing at least a structural unit corresponding to the following. 3. A step of applying the radiation-sensitive composition according to claim 1 on a substrate to form a resist film, a step of pre-baking to remove the coating solvent, a step of transferring a pattern to the resist layer by irradiation with radiation, irradiation with radiation. A pattern forming method comprising the steps of post-baking and developing with an alkaline developer to obtain a negative pattern. 4. A step of applying the radiation-sensitive composition according to claim 2 on a substrate to form a resist film, a step of prebaking to remove the coating solvent, a step of transferring a pattern to the resist layer by irradiation with radiation, irradiation with radiation. A pattern forming method comprising the steps of post-baking and developing with an alkaline developer to obtain a negative pattern.