JPS58174944A - Formation of pattern - Google Patents

Abstract

PURPOSE:To form a easily positive type resist pattern with superior resolving power by forming a water soluble photoresist film contg. a water soluble bisazido compound on a substrate, exposing the film by a specified system, and developing it. CONSTITUTION:A water soluble photoresist film of a water soluble polymer such as polyvinylpyrrolidone blended with about 1-50wt% water soluble bisazide compound such as 4,4'-diazidostilbene-2,2'-disulfonic acid as a photo-cross-linking agent is formed on a substrate. The photoresist film is imagewise exposed under conditions which decompose the photo-cross-linking agent in the exposed part without producing the cross-linking action, e.g. at <=120 deg.C high temp. in the presence of oxygen, the film is uniformly exposed under conditions which cross- link the film on the imagewise unexposed part, e.g. in a gaseous nitrogen atmosphere, and the exposed film is developed to selectively remove only the film of the imagewise exposed part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technology to which the invention pertains] The present invention relates to pattern formation using a water-soluble photoresist. [Technical background of the invention and its problems] Hitherto, it has been widely used for photoresist plate making, photoetching, and for forming fluorescent surfaces of color cathode ray tubes. These objectives g: It is said that it is safe to use and has performance similar to general pseudo-quadratic.

1. Excellent resolution; 2. Good storage stability; 3. The photoresist and developer used are free from pollution; 4. High sensitivity to light C2. As water-soluble photoresists used for this purpose, dichromium ring-forming photoresists, which are made by mixing dichromates with water-bathable polymers such as glue, gelatin, egg white, and polyvinyl alcohol, have been widely used. This is because this photoresist is extremely cheap and its sensitivity to one light C2 is relatively low. However, dichromate sparrow photoresists have extremely poor storage stability.

One week in the form of a photosensitive solution, 10 to 10 days in the form of a dry photosensitive layer
Since the 0 history C nichrome compound, which was limited to 20 minutes, is used as a photocrosslinking agent, care must be taken when handling the IA light solution and IA image solution from the standpoint of pollution and health and safety.

To improve these shortcomings, a series of nine photoresists were developed using an organic photocrosslinking agent as a photoresist.
As an example, water-bath photoresists are known that use a water-soluble bisazide compound as a photo-crosslinking agent and polyvinylpyrrolidone, polyacrylamide, or the like as a water-bath polymer to be crosslinked. This photoresist.

Although the above-mentioned performance requirements 2.3.4 were satisfied, the resolution of 1 was not satisfactory.

By the way, a series of 7 photoresists using organic solvents are mainly used in ll&tl processing departments such as medium conductor tL8 processing.
It is known for its extremely high resolution. The above photoresist is a so-called positive-type photoresist in which the exposed image area is soluble in a solvent. By the way, there are very few types of positive photoresists.In addition to the non-diazide type 7 photoresists mentioned above, there are other electron-sensitive photoresists such as polymethyl methacrylate.
limited to two. tP! 112 There have been no positive types of water-soluble two-layer photoresists. This means that after the coating is applied, the glaucoma area is dissolved and removed using a developer containing water as a living substance.

This is an extremely desirable process from the standpoint of not using organic solvents that are fundamentally harmful to the human body in the image forming process. Principle C2 Such an image forming process is impossible. [Objective of the Invention] The inventors have discovered that the Fi photosensitive solution is in an aqueous solution state, and that the image-exposed area can be removed with water. As a result of examining various ways to form a turn, we arrived at failure #4.

[Summary of the defense]

In the present invention, a water-soluble 7-photoresist film containing a water-soluble bis-and compound as a photo-crosslinking agent is provided on a substrate, and after the photo-crosslinking agent in the image-exposed area is photodecomposed without cross-linking, the entire surface is exposed to light. A pattern forming method in which the photocrosslinking agent in the image-exposed area is photolyzed and cross-linked to selectively remove only the photoresist group in the -m element part, and at least Heat the board from room temperature to 120℃
This is a pattern forming method that relies on heating at a temperature below .degree. C. or on the presence of oxygen.

To clarify, in the present invention, when a water-soluble bisazide compound, which originally acts as a photocrosslinking agent, is exposed to light under special conditions, the water-soluble polymer is exposed to light without crosslinking. C2, which has been disassembled and has a non-glossy color, is still 7
It was found that the photoresist maintains the bathing property before exposure. This phenomenon is known as a film reduction phenomenon, in which the film thickness of the 7 photoresist in the image-exposed area to which it should originally be deposited during the development process is reduced. This is 1-! To avoid it? lJeha Ik! Don't light up images in a simple atmosphere.
Which troublesome one bill did you need? The present invention solves this situation by
It uses photoresist for 14 hours.
I! The water-bathable bis-azide compound, which originally acts as a photo-crosslinking agent, is photolyzed without photo-crosslinking, and then the water-bathable bis-azide compound in the non-1-diaphragm portion is photolyzed with 1 tlII light. , crosslinking. When secured with water, only the image-exposed portions of the photoresist that have not been photo-crosslinked are selectively removed, forming a positive resist pattern. Photodecomposition of the ζ-1 element crosslinking agent without crosslinking during image-blinding light is as follows: 1. Exposure the 04 substrate to loincloth exposure using the following exposure illuminance at which normal photocrosslinking occurs at a temperature below 120°C. The temperature is raised to f2 and imagewise exposed. ■li! A method such as image exposure in the presence of an element can be applied. For C: crosslinking the photoresist film in non-image exposed areas, the reverse conditions of (1) to (2) above are used. In general, it is sufficient to provide a strong achromatic effect in air at room temperature, or to perform a complete irradiation in a nitrogen gas atmosphere.

It is not clear why the water-bathable bisazide compound, which is a crosslinking agent, does not exhibit crosslinking action when exposed under the conditions of ■ to ■ above, but the following mechanism, which has been previously explained by It is presumed that history will be encouraged under the conditions of ■. That is, when the bisazide compound Fi, which is the original crosslinking agent, is exposed to light, it photodecomposes and changes into an intermediate substance (nitrene) with strong reaction activity. Normally, this nitrene reacts with two polymer molecules to form a frame II film, but in addition, nitrene exists in the photoresist film. It also reacts with elementary molecules, and in this case, the crosslinking reaction with polymers is inhibited. That is, when #R elementary molecules exist, crosslinking reaction and insertion 1
One reaction competes with the other, and the crosslinking reaction depends on the nitrene density present in a unit volume (depending on the exposure illuminance) and the cumulative partial pressure. The condition (2) is to maintain the temperature of the substrate at a temperature below 120° C. in the heated state.

Extremely effective. Heating temperature is limited to less than 120℃!
The reason for this is that the azide compound is easily degraded by heat at temperatures above 120°C.

The water-bathable bisazide compound used according to the invention is 4,4'-diazidostilbene-2'-2'-cisuraone aL4+4'--)acidobenzalacetophenone-2-sulfone R+4+4'-diazidostilbene. -α-carboxylic acids, salts thereof, and the like. In addition, water-bathable molecules are synthesized with polyvinylpyrrolidone, polyvinyl alcohol Z, natural polymers such as gelatin, casein, and gum afbia, methyl vinyl ether, maleic acid, acrylamide, acetone, and acrylamide. Examples include grafted polymers such as any conjugated polyvinyl alcohol, acrylonitrile grafted polyvinyl alcohol, glycidyl methacrylate grafted polyvinyl alcohol, and semi-synthetic polymers such as carboxymethyl cellulose and hydroxymethyl cellulose.

The mixing ratio of the water-bathable side molecules of the water-bathable bisazide compound is 1 to 50%, preferably 5 to 20%, based on the child's ratio.

[Embodiments of the invention] Specific examples will be described below.

Example 1 A photosensitive solution having the following composition was coated on a glass substrate with a smooth surface by a spin coating method, dried with SO"C, and a photoresist film of 5600X was provided on the glass. While heating the back side of the substrate and keeping the temperature of the photoresist at 80℃, heat the original image in a hot atmosphere.

It was reduced in size and image exposure was performed using the projection exposure method. C illuminance under lightning condition t'i7 otoresist (3): 1.3
mw/ad + exposure time: 3 minutes.

Next, the temperature on the photoresist surface was set to real (22u
) After cooling at room temperature, the entire surface was exposed to light. The lighting conditions at this time were 11:3 my/al and exposure time: 5 seconds. After exposure, the glass substrate was immersed in pure water at 40'C for 1 minute and developed. After drying, C2, the resist pattern was observed, and it was found that the photoresist in the exposed areas was completely removed, and a clear pattern of 2μ was obtained. What is the nature of the pattern obtained?

The image quality C2 was comparable to that of the quinone diazide type positive resist that has been used in the past.

Polyvinylpyrrolidone 4
．． 714.4'-Diazidostilbene-2,2'-disulfonic acid = sodium salt
0.47f polyamine-based silane compound A-11
06 (manufactured by Nihon Uniriki Co., Ltd. Part name)
o, asr surfactant 0.07
5F ethyl alcohol
1.1f' pure water 195
．． 5f implementation? ＋j2 Other than using a glass substrate with a chromium film coated on the surface, is it implemented? A clear pattern of 2μ was obtained using the same method as lJ1. However, it was temporarily baked on a hot plate and immersed in a ceric ammonium nitrate solution to etch away the chromium layer in the areas not covered by the photoresist film. The pattern obtained was extremely clear and rare.

〔Effect of the invention〕

Claims (2)

[Claims] (1) A water-soluble photoresist film containing a water-soluble bisazide compound as a photo-crosslinking agent is provided on a substrate, imagewise exposed, and the photo-crosslinking agent in the image-exposed area is photodecomposed without crosslinking. , a pattern forming method in which the entire surface is exposed to light to photodecompose and crosslink the photocrosslinking agent in the non-image exposed areas, and developed to selectively remove only the photoresist film in the image exposed areas. (2) The pattern forming method according to claim 1, characterized in that the substrate is heated at a temperature from room temperature to less than 120° C. or in the presence of oxygen. .