JPS6134655B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a resist pattern using radiation such as electron beams and Regarding how to.

It is well known that resist materials are widely used to form desired patterns on substrates, for example, in the manufacture of semiconductor devices. There are two types of resist materials: positive resist materials, which form a positive image by removing the irradiated area of a radiation source such as an electron beam or There are various types of resist materials, each of which is used based on its properties.

However, conventional negative resist materials for radiation such as electron beams and X-rays do not have sufficient sensitivity to radiation and the resolution of the resulting pattern is only 2 μ
The problem was that the resolution was at its limit and unsatisfactory. Further, conventionally, when forming a resist pattern, it is necessary to use an organic solvent as a developer, and wet development using a solvent has a problem in that processing performance is inferior to transfer development and it causes environmental pollution.

Therefore, as a result of intensive research into a method of dry developing a negative pattern with good sensitivity and high resolution using radiation such as electron beams and By using a resist material consisting of a compound having a group, we succeeded in forming a high-resolution negative pattern by dry development by irradiating radiation such as X-rays and electron beams.

The method for forming a resist pattern according to the present invention includes:
A resist material consisting of a polyolefin sulfone and a compound having at least two azide groups is
It consists of exposing a desired pattern to radiation such as a beam or an electron beam, and then exposing it to an active gas plasma such as oxygen or fluorocarbon gas to form a high-resolution negative pattern.

The resist material used in the present invention is a polyolefin sulfone already known as a positive electron beam resist material, such as polyolefin sulfone, polybutene sulfone, polypentenesulfone, polyhexene sulfone, polyoctene sulfone, polycyclopentene sulfone, polycyclohexene sulfone, poly(2 -methylpentene-1-sulfone), etc., and a compound having at least two azide groups is mixed therein by a general mixing method. There is no particular limitation on the amount of the azide group-containing compound, but a preferred composition is polyolefin sulfone 50.
~97 parts by weight to 50 to 3 parts by weight of the compound having at least two azide groups. If the amount of the azide group-containing compound is less than 3 parts by weight, it tends to cause thermal pattern deformation during the dry development process, which is undesirable.On the other hand, if it exceeds 50 parts by weight, the solubility of the resist decreases. This tends to make the coating operation difficult, so it is not practical.

Representative examples of compounds having at least two azide groups include 4,4'-diazide chalcone, 2,6
-Bis(4'-azidobenzal)-cyclohexanone, 2,6-bis(4'-azidobenzal)-
Examples include 4-methylcyclohexanone, 2,6-bis(4'-azidobenzal)-acetone, and azidopyrene.

The method of forming a negative resist pattern on a substrate of Si, SiO ₂ , polycrystalline silicon, Al, etc. by radiation exposure and dry development according to the method of the present invention is as follows. A resist material made of polyolefin insulfone mixed with a compound having at least two azide groups is uniformly applied onto the coated substrate by, for example, spin coating. Next, after prebaking this coating film (e.g. at 120 to 140℃)
For about 20 to 60 minutes), the resist film is exposed to radiation such as X-rays or electron beams to form a desired pattern, and the exposed resist film is exposed to oxygen or fluorinated hydrocarbons (e.g., CF ₄ , CHF _{3 ).} , C ₂ F ₆ , C ₃ F ₈ , etc.);
A negative pattern can be formed by removing the non-exposed portions.

There are no particular limitations on the dry development conditions using activated gas plasma of oxygen or fluorinated hydrocarbons, but for example, using a coil type plasma generator in a vacuum of 0.1 to 0.8 torr under an output of 40 to 200 W for 3 to 20 minutes. By exposing the exposed resist film to plasma, the negative resist film can be suitably developed.

As explained above, according to the method of the present invention, when manufacturing a semiconductor device, for example, one layer is placed on a substrate.
Since a high-resolution negative pattern of .mu.-1.mu. line and space can be formed by radiation irradiation using dry development, its practical value is also extremely great.

Examples of the present invention will be described below.

Example 1 Polybutenesulfone (mole of butene and sulfone = 10:8, number average molecular weight = 3 × 10 ⁵ ) and 2.
6-bis-(4'-azidobenzal)-4-methylcyclohexanone was mixed in a ratio of 4:1, and the resulting mixture was dissolved in methyl cellosolve acetate to form an 8% solution. This solution was then spin-coated onto a silicon wafer and
A resist film with a thickness of 1.5 Å was obtained, which was prebaked at 120° C. for 20 minutes and then exposed to an electron beam (acceleration voltage: 20 keV) in a desired pattern. The exposure amount is 6×10 ^-6 C/cm ²
It was hot.

Next, this exposed resist film was exposed to plasma at 80 W for 15 minutes by introducing 0.4 torr of CF ₄ gas into a coil-type plasma generator, and the result was 1μ
-1μ line and space
We were able to form a negative pattern with a resolution of .

Example 2 10 parts by weight of the polybutenesulfone prepared in Example 1 and 1 part by weight of 2,6-bis-(4'-azidobenzal)-acetone were mixed, and this mixture was dissolved in methyl cellosolve acetate to give 8 parts by weight. % solution. This solution was spin-coated onto a silicon wafer to obtain a 7000 Å thin film, and after prebaking at 120°C for 20 minutes, this resist film was applied to an accelerating voltage.
It was exposed to a 20 KeV electron beam in a desired pattern (exposure amount: 7×10 ⁻⁶ C/cm ² ).

Next, this exposed resist film is heated to 0.4 torr of oxygen gas in a coil-type plasma generator.
When exposed to plasma at 50W for 15 minutes,
A negative pattern with a line and space resolution of 1μ-1μ was obtained.

Example 3 In the same manner as in Example 1, polypentene sulfone with a molar ratio of pentene and SO ₂ of 6:4 and a minute average molecular weight of 1.5×10 ⁵ was prepared from pentene and liquid sulfite. 2.6-bis-
(4'-azidobenzal)-4-methylcyclohexanone was mixed at a ratio of 10:2 (weight ratio).
The resulting mixture was dissolved in methyl cellosolve acetate to form an 8% solution and spin coated onto a silicon wafer to obtain a 1 μm thin film. After prebaking this thin film at 110° C. for 20 minutes, it was exposed to a desired pattern with an electron beam at an acceleration voltage of 20 KeV (exposure amount: 8×10 ⁻⁶ C/cm ² ).

Next, this exposed resist film was exposed to plasma at 80W for 8 minutes in a coil-type plasma generator by introducing 0.4torr of _CF4 gas.
A negative pattern with line and space resolution of μ-1 μ was obtained.

Example 4 2 was carried out in the same manner as in Example 2 except that the plasma active gas in Example 2 was changed from oxygen gas to C ₂ F ₆ gas and exposed to plasma at 0.8 torr and 100 W for 5 minutes.
A negative pattern with a line-and-space resolution of μ-1μ was obtained.

Claims (1)

[Claims] 1. A resist material consisting of a polyolefin sulfone and a compound having at least two azide groups is exposed to radiation such as X-rays or electron beams in a desired pattern, and then activated by oxygen or fluorocarbon gas, etc. A method for forming a resist pattern, characterized by forming a high-resolution negative pattern by exposing it to gas plasma. 2 The resist material is polyolefin insulfone
A method according to claim 1, comprising from 50 to 97 parts by weight and from 3 to 50 parts by weight of a compound having at least two azide groups.