JPH03182756A - Formation of resist pattern - Google Patents

Abstract

PURPOSE:To obviate the remaining of development by using any of liquid mixtures composed of xylene, carbon tetrachloride, etc., as a rinse liquid at the time of coating a substrate with a specific positive type resist, then irradiating the resist with ionizing radiation to selectively expose the resist and developing the resist. CONSTITUTION:The surface of the semiconductor substrate is coated with the positive type resist which consists of a 1:1 copolymer of alpha-methyl chloroacrylate and alpha-methyl styrene and is expressed by formula I. The solvent having the dissolving power to the extent of not eluting the unexposed part of the resist, for example, any one of the soln. mixtures composed of the carbon tetrachloride, xylene, methyl isobutyl ketone, methyl isobutyl ketone, and isopropyl alcohol, is used as the rinse liquid to be used for the rinse processing to be executed in succession to development in the processing stage for forming the resist patterns by irradiating the resist with the ionizing radiation to selectively expose the resist and developing the resist. Thus, the remaining of the development of the resist is obviated.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for forming a resist pattern, the purpose of this method is to form a copolymer of α-methylstyrene and α-methyl chloroacrylate on a semiconductor substrate with the aim of eliminating development residue on the resist. After coating a positive resist represented by the structural formula below, the resist is selectively exposed to light by irradiating it with ionizing radiation, and developed to form a resist pattern. After that, carbon tetrachloride, xylene, methyl isobutyl ketone.

The method for forming a resist pattern is characterized in that a rinsing treatment is performed using one of a mixed solution of methyl isobutyl ketone and isopropyl alcohol.

however, 0〈m.

n<100 [Industrial Application Field] The present invention relates to a method for forming a resist pattern with improved sensitivity.

Semiconductor integrated circuits have become more integrated and LSI and VLSI have been put into practical use, but this has been achieved by miniaturizing conductor lines and electrodes, and currently the minimum pattern width is less than lt1m1 (submicron). It has even been put into practical use.

Initially, ultraviolet light was used as an exposure light source to form fine resist patterns, but due to wavelength limitations, the minimum line width was limited to about 1.5 μm.

Therefore, exposure to ionizing radiation such as electron beams and X-rays has come to be used instead.

In this X, the wavelength of the electron beam varies depending on the accelerating voltage\,
Since it is extremely short, at about 0.1 in., it is possible to form fine patterns in the submicron range.

The present invention relates to a processing method for forming a fine pattern by eliminating development residue when forming a resist pattern by electron beam exposure.

[Conventional technology]

The inventors used α-methylstyrene and α-methylstyrene represented by the above formula (1) as resists with good resolution and excellent dry etching resistance for forming submicron patterns.
We have proposed a positive resist for electron beams made of a copolymer of methyl chloroacrylate.

(Unexamined Japanese Patent Publication No. 63-137227, published on November 29, 1986, Ijl) This resist shows excellent performance in terms of resolution and dry etching resistance, and can be improved by using an appropriate developer. Sensitization was also achieved.

However, when forming a pattern with very high density, there is a problem that residual development tends to occur.

(Problem to be solved by the invention) As mentioned above, the inventors have discovered that α-methylstyrene and α-methylstyrene
-The use of a positive resist for electron beams made of a copolymer of methyl chloroacrylate has been proposed, but when forming a very high density resist pattern, there is a lot of development residue.
This has caused a problem of lower yield.

Therefore, the problem is to eliminate this development residue.

[Means to solve the problem]

The problem mentioned above is that α-methylstyrene and α-
After coating a positive resist made of a copolymer with methyl chloroacrylate and having the structural formula below, the resist is selectively exposed to light by irradiating it with ionizing radiation, and then developed to form a resist pattern. In the processing step, a solvent with a dissolving power that does not dissolve the unexposed areas of the resist, such as carbon tetrachloride, xylene,
This problem can be solved by configuring the resist pattern forming method using either methyl isobutyl ketone or a mixed solution of methyl isobutyl ketone and isopropyl alcohol.

[Effect]

An advantage of the present invention is that the resist represented by the above formula (1) uses very strong developing conditions in order to be used with high sensitivity.

For this reason, if the developer is rapidly evaporated and removed by a method such as nitrogen (Nt) gas blowing or spin-off after development, the polymer dissolved in the developer will precipitate and become a development residue.

Therefore, it is necessary to wash out the developer containing the polymer on the substrate by rinsing and then dry the substrate.

Usually, a rinsing liquid that does not dissolve the polymer is used, but if a solution that does not dissolve the polymer at all is used, the solubility will be extremely reduced, resulting in development residue.

Therefore, in the present invention, it is desirable to use a solvent that has enough dissolving power to not dissolve the unexposed areas. Examples of such solvents include carbon tetrachloride, xylene, methyl isobutyl ketone (abbreviated as MIBK), and methyl isobutyl ketone (abbreviated as MIBK). MIBK
) and isopropyl alcohol (abbreviated as IP^) is suitable, and by using this as a rinsing liquid, it is possible to eliminate development residue.

〔Example〕

tit copolymer of α-methylstyrene and α-methyl chloroacrylate (average weight molecular weight 56,000° dispersity 2)
．． 0) in O-dichlorobenzene to prepare a resist solution, and apply 5ooo on the reticle substrate using the spin code method.
Apply to human thickness and heat on hot plate at 200°C for 10 minutes.
After baking for a minute, electron beam exposure was performed at an accelerating voltage of 20 KV.

This was subjected to subere development using ethylbenzene for 10 minutes, and then the development residue was examined using the solvent shown in Table 1 as a rinsing agent.

Table 1 The results are shown in Table 1 for xylene, carbon tetrachloride,
There is no development residue when using MIBK or a mixture of MIBK and IPA as a rinse solution, but acetone.

When a solvent in which the polymer does not dissolve at all, such as isooctane or cyclohexane/ethylbenzene, is used as a rinsing liquid, development residue is generated.

For the solvents listed in Table 1, the rinsing time is 30
The results were exactly the same when the time was shortened to seconds.

〔Effect of the invention〕

As described above, xylene is used as a rinsing liquid when developing a resist made of a copolymer of α-methylstyrene and α-methyl chloroacrylate.

Carbon tetrachloride, ? IIBK,? By using either a mixture of IIBK and IPA, it is possible to eliminate development residue.

Claims (1)

[Claims] After coating a semiconductor substrate with a positive resist made of a copolymer of α-methylstyrene and α-methyl chloroacrylate and having the following structural formula, the resist is irradiated with ionizing radiation. In the process of selectively exposing the resist to light and developing it to form a resist pattern, after the development is completed, any of carbon tetrachloride, xylene, methyl isobutyl ketone, or a mixed solution of methyl isobutyl ketone and isopropyl alcohol is used. A method for forming a resist pattern, characterized in that a rinsing process is performed using one of the above. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) However, 0<m, n<100