JPS60134234A - Negative type resist composition - Google Patents

Abstract

PURPOSE:To obtain a negative type resist having high resolution by substituting glycidyl groups for hydroxyl groups in polyhydroxystyrene. CONSTITUTION:A copolymer consisting of p-hydroxystyrene and styrene p-glycidyl ether is irradiated with electron beams, X-rays or far ultraviolet rays, and alkali development is carried out. The copolymer is represented by the formula and contains 1-50mol% styrene p-glycidyl ether. When bisazido groups as a sensitizer are substituted for hydroxyl groups in poly-p-hydroxystyrene, the resulting copolymer has sensitivity only to ultraviolet rays. This copolymer having glycidyl groups has sensitivity to electron beams and X-rays besides ultraviolet rays and shows high resolving power. It is synthesized by reacting poly-p-hydroxystyrene with epichlorohydrin.

Description

Detailed Description of the Invention (al) Technical Field of the Invention The present invention uses ionizing radiation such as electron beams and X-rays as a light source.
Regarding the negative resist material used.

(1)) Technical Background Various electronic circuit elements such as semiconductor ICs are used as Z substrates such as semiconductor crystals, ferroelectric crystals, and ferroelectric crystals.

LS1. Surface acoustic wave filters, magnetic bubble memories, etc. are being made.

Here, the miniaturization, cylinder density, and performance of these electronic circuit elements are progressing more and more, and extremely fine patterns are used as a method for realizing this.

Here, thin film formation technology and photolithography are used to form fine patterns, and photoresist and photoetching are applied to the substrate to be processed or a thin layer formed by epitaxial growth or vacuum evaporation on the substrate. Fine patterns are formed using the photo-etching technique used.

That is, the resist Y is coated on the substrate to be processed by a spin code method, and when the irradiated portion is irradiated with light such as ultraviolet rays through a mask, the quality of the irradiated portion is changed.

For example, negative-tone resists take advantage of the fact that cross-linking or polycondensation reactions progress in the light-irradiated areas, making them insoluble in developing solutions, while positive-tone resists take advantage of the fact that a decomposition reaction progresses in the light-irradiated areas, making them insoluble. This method uses molten development.

The theoretical limit for resist resolution when using ultraviolet light as a light source is approximately 0.5 [μm], but since light diffraction and scattering are involved, the practical limit is 1 to 2 [μm].
It is difficult to form a so-called submicron pattern of [μm] or less.

On the other hand, if short-wavelength electromagnetic waves such as electron beams and soft X@ are used, this theoretical limit is lowered, making it possible to form a pattern with a width of 0.1 [μ door].

For this reason, ionizing radiation such as electron beams, soft X-rays, and far ultraviolet rays is used as a light source to form fine patterns.

However, the resists used for this purpose have completely different photosensitive wavelengths, so even if conventional ultraviolet resists are used as they are, they have poor sensitivity and resolution, making it impossible to obtain good results. A resist is a must-see.

The present invention relates to the composition of a negative resist with high resolution.

fcl Prior Art and Problems Conventionally used negative electron beam resists include those based on chloromethylated polystyrene (abbreviated as CMS) and cyclized polyisoprene.

However, these resists have a problem in that the resin swells during development using an organic solvent, resulting in a decrease in resolution.

(dl) Purpose of the Invention The purpose of the present invention is to provide a negative type resist Y suitable for ionizing radiation such as electron beams, X-rays, and far ultraviolet rays and having good resolution.

tel Structure of the Invention The object of the present invention is to combine P-hydroxystyrene and styrene P-
The molar ratio of styrene P-glycidyl ether in the copolymer with glycidyl ether is 1 to 50%,
This can be achieved by using a negative resist composition characterized in that crosslinking of the exposed area progresses upon irradiation with ionizing radiation, making it poorly soluble in a developer.

Embodiments of the Invention The present invention relates to a resist comprising a copolymer of P-hydroxystyrene and styrene P-glycidyl ether represented by the following structural formula.

OH0 The present invention focuses on the fact that high resolution is a necessary condition for a resist for forming fine patterns, and that the resolution of conventional resists is reduced due to swelling when developed with an organic solvent. High resolution has been achieved by using a material that can be developed with alkali.

That is, P-hydroxystyrene was used as a base material because it dissolves quickly in an alkaline aqueous solution and swelling is significantly controlled, and Grindyl base material was selected as a base material that is sensitive to ionizing radiation, and YM was added to this base material. It is made of a co-integrated material of P-hydroxystyrene and styrene P-glycidyl ether.

Various types of ultraviolet resists using P-hydroxystyrene as a base material are known.

For example, Shipley's positive photoresist MF32 is P
- Hydroxystyrene is used as a base material and a naphthoquinone diazide derivative is added as a photosensitizer.

Also, Hitachi's negative photoresist RD-200ON is P-
They are made of hydroxystyrene as a base material and a bisand compound is added thereto as a photosensitizer.
It is unsuitable as a resist for ionizing radiation such as lines.

The method of producing the copolymer according to the present invention and its examples are as follows.

Production method: Poly P-hydroxystyrene 60 with an average molecular weight of approximately 10,000
ω and 1.0 cgl of shrimp chlorohydrin were dissolved in 50 ω of tetrahydrofuran and heated to 45 cOI for 10 (
Two drops of JZll's dehydrated liquid are added dropwise to react.

Reaction e was added to 60[O] and stirred for 15 hours. Next, the reaction solution (ytl) was added to water, the resulting solid 14-dioxane was dissolved, and a resin was obtained by freeze-drying.

Example: A copolymer of P-hydroxystyrene and styrene P-glycidyl ether was dissolved in cyclohexanone and coated on a silicon (Si) substrate by a spin-coating method.
It was baked in a nitrogen (N2) stream at 80°C for 20 minutes.

The resist film thus made is applied at an accelerating voltage of 20 (KV).
After exposure by irradiating with an electron beam at ), the film was developed and processed for 60 seconds using Microposit MF-312 developer manufactured by Zinopray.

By this development, the resist film in the unexposed 0 part was completely dissolved, and the sensitivity (Dg") at this time was 5 [μC/CIA]. Also, in terms of resolution, this resist film had a film thickness of 1 [μC/CIA]. μm
] Under the conditions, a 1.0 [μm] line-and-paste could be resolved.

(gl Effect of invention The present invention is CMS, which is a conventional electron beam resist.

Since cyclized polyimbrene and the like use an organic solvent 7 as a developer, the resin swells, resulting in a decrease in resolution.Using the resist of the present invention, which can be developed with an alkaline aqueous solution, reduces swelling. This makes it possible to maintain high resolution.

Claims (1)

[Claims] The molar ratio of styrene P-glycidyl ether in the copolymer of P-hydroxystyrene and styrene P-glycidyl ether is comprised between 1 and 50, and crosslinking of the exposed area progresses by irradiation with ionizing radiation, resulting in development. A negative resist composition characterized by being poorly soluble in liquids.