JPH0334058B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a pattern on a water-soluble photosensitive material.

Conventionally, water-soluble photosensitive substances include hydrophilic resins such as egg white, gris, casein, polyvinyl alcohol, and gelatin, and a photopolymerization initiator (hereinafter referred to as photosensitive main agent).
There are also those to which dichromate, chromate, or diazo compounds are added, and all of them are negative-type.

On the other hand, these photosensitive substances (hereinafter referred to as photosensitive liquids)
Applications include etching masks for shadow masks of color cathode ray tubes, color stripes used in image pickup tubes and solid-state image pickup plates of color television cameras, colored bases for mosaic filters, and collotype printing.

The following steps are generally used to use these water-soluble photosensitive liquids.

Adjustment of photosensitive liquid base, addition of photosensitive main agent,
Application of photosensitive liquid onto the substrate, pre-baking, mask exposure, hot or cold water development, burning, etching mask, coloring base, printing original plate, etc. are completed.

Note that since the pot life of the photosensitive solution is short, the photosensitive main agent is generally added immediately before use.

However, the gelatin-based photosensitive liquids currently in use have major drawbacks compared to other photosensitive liquids such as grieux and casein.

In other words, in the conventionally commonly used gelatin-based photosensitive liquids, the main ingredient gelatin is polymeric gelatin (photographic gelatin, general industrial gelatin) with a molecular weight of 100,000 to 250,000 obtained by lime-treating cow bones and then extracting them with hot water. gelatin, edible gelatin, etc.), so if the gelatin concentration in water is 10-20%, the
Almost gelatinizes at 25°C (25°C ± 5°C even at a concentration of 10 to 20% for green and casein photosensitive solutions)
It does not gel at temperatures around ℃).

Therefore, the gelatin photosensitive solution coating work should be carried out at 25°C.
When carried out at ±5° C., so-called room temperature, gelation occurs during coating even if the photosensitive solution is heated in advance, making it impossible to coat smoothly and making it extremely difficult to control the film thickness. Therefore, generally 40~45℃
Currently, it is carried out in a constant temperature room,
Considering the operation of a thermostatic chamber at 40 to 45°C and the rationalization of the coating process, there is a long-awaited need for a gelatin-based photosensitive liquid that does not gel even at room temperature.

In view of the above-mentioned drawbacks of conventional gelatin-based photosensitive solutions, the purpose of the present invention is to reliably form fine patterns using a gelatin-based water-soluble photosensitive material that does not gel even at room temperature (25°C ± 5°C). The purpose is to provide a method.

It is generally known that gelatin has a lower gelation temperature as its molecular weight decreases.

Therefore, the collagen in bovine bones is treated with chemicals in advance to remove unnecessary organic matter, and then decomposed and extracted with proteolytic enzymes, resulting in an average molecular weight of 30,000~30,000.
Manufacture 70,000 water-soluble low-molecular-weight gelatin.

This low-molecular-weight gelatin has almost the same properties as general high-molecular-weight gelatin, except for its weak gelling ability, and can be dissolved in water at room temperature.

If the above-mentioned low-molecular-weight gelatin is used and a photosensitive agent made of dichromate is added to prepare a photosensitive solution, it will not gel and will not generate stars even at room temperature (25°C ± 5°C). , it is possible to produce gelatin-based photosensitive liquids with excellent hardening action, and it is possible to form fine patterns.

Experimental examples and examples of the present invention are shown below.

Experimental example 1 Water 1000c.c. Gelatin molecular weight (5000-10000) 400g Ammonium dichromate 80g Alcohol 60c.c. Benzoin tincture 50c.c. Chrome alum (0.2% aqueous solution) 20c.c. Mix and dissolve the above ( 50~60℃) then 10℃
I cooled it down to a temperature and left it for a day, but no gelation occurred.
The viscosity was 140 cps at room temperature. After coating on a glass substrate, exposure to ultraviolet light and cold water development (3 minutes) using a chrome mask with a test pattern formed produced the pattern shown in the micrograph (120x magnification) in Figure 1. In addition, in the case of spinner coating at 3000 rpm, the thickness of the coating film was 0.7 μm. Also,
In the same photo, the numbers indicate the dimensions (in microns)
It shows.

In FIG. 1, 1 is the remaining part of the photosensitive layer, 2 is the missing part of the photosensitive layer, and 3 is the pattern part. As can be seen from the figure, this photosensitive solution can be used to form a pattern by cold water development.

Experimental Example 2 In Experimental Example 1, the amount of ammonium dichromate, which is the main photosensitive agent, was added to 50g, and the molecular weight of gelatin was adjusted to 50g.
Even if the experiment was conducted under the same conditions except for using 300 g of 10,000 to 20,000, gelation did not occur and the viscosity did not change.
It was about 450 cps, and a similar pattern was formed. Figure 2 shows a photograph of the sample that was then stained with Eriosin Scarlet RE dye from Ciba Geigy, Japan. In addition, in the case of spinner coating at 3000 rpm using a photosensitive solution under these conditions, the thickness of the coating film is 1.5 μm, and the boundaries of the pattern edges are more clearly defined.

Experimental Example 3 In Experimental Example 1, the experiment was conducted under the same conditions except that the amount of dichromium ammonium used as the main photosensitive agent was 25g gelatin and 150g of photographic gelatin with a molecular weight of 150,000 to 250,000 was used, but the room temperature was 25 It remained completely gelled even at ℃. Therefore, after re-dissolving at 50°C, it was coated, exposed, developed in cold water for 10 minutes, and dyed. The results are shown in Figure 3.

In FIG. 3, 1 indicates the remaining portion of the photosensitive layer, 2 indicates the missing portion of the photosensitive layer, and 4 indicates the photosensitive layer that cannot be completely removed and partially remains. From the results shown in the figure, it can be seen that conventional photosensitive solutions cannot be developed with cold water.

Experimental Example 4 In Experimental Example 3, an experiment was conducted under the same conditions except that general industrial gelatin (molecular weight 100,000 to 200,000, 150 g) was used, and gelatin formed after being left at 10° C. for one day. However, in this case, gelation did not occur even after redissolving at about 40°C and cooling to 25°C, but no sharp pattern was formed after coating, exposure, and cold water development, as in Experimental Example 3. .

Next, examples of the present invention will be described.

Example water 1000c.c. Gelatin (molecular weight 30000-70000) 200g Potassium dichromate 20g Ammonium dichromate 20g Lead nitrate 2.5g Alcohol 30c.c. After thoroughly mixing and dissolving the above (50-60℃), 20℃
The mixture was cooled to a temperature of 100 mL and left for one day, but gelation did not occur and the viscosity was 270 cps. Furthermore, after coating a glass substrate, if UV exposure is performed using a chrome mask on which a test pattern has been formed, a pattern with a line width of about 3 μm can be formed. In this example, potassium dichromate and ammonium dichromate are used as the main photosensitive agents, and lead nitrate is used as an auxiliary agent. When the molecular weight is as large as 30,000 or more, it becomes difficult to dissolve in water, so film peeling and pattern flow are less likely to occur during development with water, making it possible to reliably form fine patterns with a width of 3 μm.

The adjuvant lead nitrate has the effect of suppressing the formation of gelatin stars (gelled lumps), and alcohol etc. have the effect of preventing foaming and improving spreadability.

According to the above examples, by preparing a gelatin photosensitive solution containing low molecular weight gelatin (molecular weight 30,000 to 70,000) as the main component and adding a photosensitive main agent consisting of dichromate, gelation does not occur even at room temperature, and It is possible to produce gelatin-based photosensitive liquids whose viscosity changes slowly,
It has become clear that fine patterns of 3 μm can be reliably formed by exposure and water development.

Therefore, by forming a pattern using this photosensitive liquid, even if the coating process is performed at room temperature and water development is performed, the film thickness can be easily controlled, and a uniform fine pattern can be formed without film loss. Therefore, the effect of streamlining the coating and developing process and saving energy is very large, and it is very advantageous for forming fine patterns of about 3 μm for coloring and the like.

Furthermore, in the above examples, gelation was confirmed using dichromate as a photopolymerization initiator, but
Dichromate may be added immediately before use.

As described above, by using the present invention, it is possible to reliably form a fine pattern of about 3 μm using a gelatin-based water-soluble photosensitive material with an optimum molecular weight of 30,000 to 70,000, and it is possible to form fine patterns of about 3 μm, etc. It greatly contributes to pattern formation.

[Brief explanation of drawings]

FIG. 1 is an enlarged view showing the state of pattern formation using a water-soluble photosensitive material in an experimental example, and FIG. 2 is an enlarged view of a pattern formed by dyeing after pattern formation using a water-soluble photosensitive material in another experimental example. Third
The figure shows a pattern formed using a conventional water-soluble photosensitive material, but is an enlarged view of the pattern showing that pattern formation does not go well with cold water development. 1... Photosensitive liquid remaining portion, 2... Photosensitive liquid missing portion, 3... Pattern portion.

Claims (1)

[Claims] 1 Prepare a water-soluble photosensitive solution containing gelatin with a molecular weight of 30,000 to 70,000, which has been decomposed and extracted, as the main components and water, and add a photosensitive main agent consisting of dichromate, apply the photosensitive solution at room temperature, expose to light, and water. A method for forming a pattern on a water-soluble photosensitive material, the method comprising forming a pattern by developing the material.