JPH0146980B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a pattern forming method, and more particularly to a pattern forming method for a non-luminescent light absorbing material coating of a black stripe type color picture tube. For example, a photoresist is used to form the black stripe pattern of a color picture tube, and the characteristics of this photoresist are that it is water-soluble, has high sensitivity, has no dark reaction or heat fog, and has strong adhesion. In addition, it must satisfy many characteristics such as good developability and easy peeling of a photoresist cured by light. Conventionally, so-called photoresists made of polyvinyl alcohol (PVA) and ammonium dichromate (ADC) or sodium dichromate (SDC) have been used to form a non-luminescent light-absorbing material coating for color picture tubes.
PVA-ADC photoresist, a photoresist consisting of PVA and a water-soluble diazonium compound (DIAZO), so-called PVA-diazo photoresist, or a photoresist consisting of polyvinylpyrrolidone (PVP) and a water-soluble bisazide compound (AZIDE), so-called PVP-azide. Photoresists and the like are known. However, each of these conventionally known photoresists has advantages and disadvantages.
At present, there is no photoresist that satisfies all of the above-mentioned properties when forming a non-luminescent light-absorbing material coating on the fluorescent surface of a color picture tube. For example, PVA-ADC photoresists have high sensitivity, but on the other hand, the sensitivity changes depending on the exposure amount.
Because of the so-called γ, it is difficult to control the size of the holes in the non-luminescent light-absorbing material coating, and furthermore, dark reactions and heat fogging may occur, so the working range is narrow and detailed management is required. PVA-diazo photoresists have strong adhesion, but on the other hand, they have very poor developability and low sensitivity, making them of little practical use. Furthermore, although PVP-azide photoresists have good developability, they do not have adhesion properties, and they also have so-called reciprocity failure characteristics, meaning that sufficient pattern formation cannot be achieved unless the light is strong above a certain level. There are limitations when it comes to baking. Next, a method for forming a pattern of a non-luminescent light-absorbing substance coating on the fluorescent surface of a color picture tube, characteristics required of a photoresist, characteristics of conventional photoresists, etc. will be explained. First, a non-luminescent light-absorbing material coating on the fluorescent surface of the color picture tube is formed by the following process. (1) Resist coat: Apply photoresist to the inner surface of the face panel and dry to form a photoresist film. (2) Exposure: Attach a shadow mask and expose R,
Light is irradiated to the positions where holes for the G and B3 primary color phosphor layers are to be formed. (3) Development: Remove the shadow mask and develop with water, leaving the hardened photoresist dots and washing away the other areas. (4) Formation of non-luminescent light-absorbing material film: Coat a colloidal black carbon suspension on the inner surface of the face glass and dry. (5) Peeling: Pour a stripping solution to remove the hardened photoresist and form holes in the non-luminescent light absorbing material film. (6) The subsequent steps such as formation of the three-color phosphor layer, aluminizing, and frit baking electron gun device are almost the same as conventional ones. In such a process, the following quality is required for the holes formed in the non-luminescent light absorbing material film. (1) Sharp hole edges (2) Very little overall unevenness In addition to these, the following properties are required of photoresists in order to stably produce the above-mentioned quality. (3) Adhesion of the coating film: If this is weak, the cured film will fall off during development, and in extreme cases, holes will not be formed. (4) Sensitivity: If the sensitivity is low, a long exposure time is required, resulting in poor workability. On the other hand, as shown in Table 1, conventional photoresists that satisfy all of these characteristics have not been obtained.

[Table] The present invention was made in view of the above-mentioned conventional problems, and particularly relates to a photoresist used for pattern formation of a fluorescent surface of a color picture tube having a non-luminous light-absorbing substance coating on the inner surface of the face panel. The object of the present invention is to provide a method for forming a pattern using a novel photoresist that fully satisfies the characteristics and provides high sensitivity and a wide working range. As a result of examining various water-soluble photoresists that do not have the above-mentioned problems, the inventor found that when a water-soluble polymer is used in combination with a water-soluble bisazide compound and a water-soluble diazo compound as a crosslinking agent, the drawbacks of the azide photoresist are found. Not only is the adhesion strength improved, the photosensitivity and thermal stability of the photosensitive solution, which are disadvantages of diazo photoresists, surprisingly, when these crosslinking agents are used together, the synergistic effect of the crosslinking agents is improved. It was found that extremely high sensitivity, which cannot be obtained when a crosslinking agent is used alone, can be obtained. That is,
The photoresist according to the present invention is (1) a photoresist comprising a water-soluble bisazide compound, a water-soluble diazo compound, and a water-soluble polymer material. (2) The water-soluble polymer material is a mixture of polyvinylpyrrolidone and polyvinyl alcohol, and the weight ratio of polyvinylpyrrolidone to polyvinyl alcohol is in the range of 0.5 to 3.0, and the water-soluble bisazide compound is a water-soluble diazo The proportion to the compound is 3.0 to 7.0 by weight
It is characterized by being within the range of . Next, a method for forming a pattern using a photoresist according to the present invention will be explained in detail. First, water-soluble bisazide compounds used in the present invention include, for example, 4,4'-diazidostilbene 2,2'-disulfonic acid, 4,4'-diazidobenzalacetophenone-2
-sulfonic acid, 4,4'-diazidostilbene-2-carboxylic acid, and salts thereof. Examples of water-soluble diazo compounds include benzidine tetrazonium chloride, 3,3'-dimethylbenzine tetrazonium chloride, 3,3'-dimethoxybenzidine tetrazonium chloride, and 4,4'-diaminodiphelamine. These are tetrazonium chloride, tetrazonium sulfate of 3,3'-diethylbenzidine, formalin condensate of diazodiphenylamine, and their double salts. Examples of water-soluble polymer materials include polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyvinyl methyl ether,
Synthetic polymers such as polyvinyl acetal and polyacrylic acid, natural polymers such as gelatin, silica, gum arabic, and casein, copolymers of methyl vinyl ether and maleic acid, acrylamide and diacetone acrylamide, acrylamide and vinyl alcohol, and acrylonitrile grafts. polyvinyl alcohol, glycidyl methacrylate grafted polyvinyl alcohol, β-
Examples include grafted polymers such as oxyethyl methacrylate grafted polyvinyl alcohol, semi-synthetic polymer materials such as carboxymethyl cellulose, hydroxymethyl cellulose, hydroxypropyl cellulose, and poly L-glutamic acid (Na salt). At least one of these water-soluble polymer materials must be crosslinked with a water-soluble bisazide compound or a water-soluble diazo compound by the action of ultraviolet light.
A particularly preferred example is when polyvinylpyrrolidone and polyvinyl alcohol are used in combination.
In this case, the proportion of polyvinylpyrrolidone to polyvinyl alcohol is 0.1 to 0.1 by weight.
8.0, preferably in the range of 0.5 to 3.0. This is because if it is less than 0.5, a clear pattern cannot be obtained, and if it exceeds 3.0, the adhesion force decreases. When polyvinylpyrrolidone and polyvinyl alcohol are used under the above conditions, the ratio of the water-soluble bisazide compound to the water-soluble diazo compound must be selected in a weight ratio of 1 to 10, preferably 3 to 7. This is because if the number is less than 3, the photosensitivity will be low, and if it is more than 7, the adhesive force will be reduced. In addition to the water-soluble polymer material, water-soluble bisazide compound and water-soluble diazo compound mentioned above, a small amount of surfactant such as polyethylene glycol, alkyl phenoxy polyethylene oxide phosphate ester sodium hexametaphosphate, etc. is also added to the photosensitive solution. Alcohols, such as alcohol, glycerin, ethylene glycol, sorbitol,
It can be added to tributyl alcohol or the like to improve the antifoaming properties of photosensitive liquids and the forming properties of photosensitive films. Next, a first example will be described. A water-soluble photoresist having the composition shown in Table 2 was prepared, and its properties were investigated by applying it to a non-luminescent light-absorbing material coating process.

【table】

[Table] Note 1: K-90 (manufactured by GAF (USA), trade name) Note 2: EG-40 (manufactured by Nippon Gosei Co., Ltd., trade name) Note 3: 4,4'-Diazidostilbene-2 , Sodium 2'-disulfonate Note 4: Formalin condensate of diazodiphenylamine (phosphate) Note 5: The ratio of the sum of PVP and PVA to the water-soluble photoresist is 0.01 (constant) by weight.
The ratio of the sum of azide and diazo to the sum of PVP and PVA is 0.07 (constant) by weight.
I kept it. The remainder of the water-soluble photoresist is pure water. The results of examining the photosensitivity to ultraviolet light are shown in FIG. (Corresponding to composition numbers #8 to 14) Sensitivity here refers to the exposure time required to obtain a pattern size with a shadow mask diameter of 0.200 mm to 0.190 mm (center area) in a 20-inch black stripe color picture tube (illuminance 30000 lux). It is. From curve 21, the maximum sensitivity is obtained near azide/diazo = 5, and the value is more than twice the sensitivity of azide-based photoresists, which are said to have superior photosensitivity. I understand. Furthermore, it can be seen that when the ratio of azide/diazo is 3 or less, the sensitivity of the diazo photoresist becomes dominant. This curve 21 is
This was done with PVP/PVA=1. Next, the effect on adhesion was investigated and the results are shown in Figure 2. As can be seen from curve 22, when the azide/diazo ratio increases to 7 or more, the adhesion force gradually decreases. This curve 22 was also performed with PVP/PVA=1. However, ◎: Very good, ○: Good, △: Slightly poor, ×: Poor, and the practical level is in the range of ◎ to ○. Figures 3 and 4 show the results of investigating the adhesion force and pattern clarity when changing the PVP/PVA ratio (composition numbers #1 to 7).
Compatible with ) As can be seen from curves 23 and 24, PVP/
It can be seen that the appropriate blending ratio of PVA is in the range of 0.5 to 3.0. ◎, 〇, △, and × are the same as in Fig. 2. After forming a graphite film on the inner surface of the face having the patterned film thus obtained, the patterned film was peeled off using a saturated sodium sulfamate solution. As a result, patterned films of all compositions could be easily peeled off. It turned out that there were no problems at all. In addition, as a result of examining the storage stability of three photosensitive liquids with compositions #3, #8, and #14 left at room temperature for one month, it was found that #3, #14, that is, the water-soluble It was found that the sensitivity of the photoresist, a known azide-based photoresist, was almost unchanged from the initial stage of adjustment. On the other hand, it was found that #8, ie, a known diazo photoresist, required an exposure time of 60 seconds or more, and the sensitivity was reduced to 50% to 70% compared to the initial value. Next, a second embodiment will be explained. In this case, the third embodiment
The characteristics of the photoresist were investigated in the same manner as in the first example except that a water-soluble photoresist having the composition shown in the table was used. As a result, the sensitivity was 30,000 lux,
The sensitivity was 13 seconds, which was close to the sensitivity of composition #11 of the first example. In addition, the pattern adhesion, pattern clarity, and release properties against sodium sulfamate were also good.

【table】

[Table] To summarize the above, the photoresist is composed of a water-soluble bisazide compound, a water-soluble diazo compound, and a water-soluble polymer material. In particular, the water-soluble polymer material is a blend of polyvinylpyrrolidone and polyvinyl alcohol, and this polyvinylpyrrolidone Compounding ratio of polyvinyl alcohol to polyvinyl alcohol by weight
By adjusting the weight ratio of the water-soluble bisazide compound to the water-soluble diazo compound to be in the range of 3.0 to 7.0, the cracking and overall unevenness of the non-luminescent light-absorbing substance coating can be reduced by bisazide/
The results showed that the adhesive strength was comparable to that of PVP resists, the adhesion strength was comparable to that of diazo/PVA resists, and the sensitivity exceeded the maximum value of both resists by up to 30%. As mentioned above, the pattern forming method of the present invention eliminates the drawbacks of each individual resist by mixing two conventional water-soluble resists with different characteristics and a water-soluble polymer material in predetermined amounts, and also eliminates the disadvantages of each resist alone. It is also possible to obtain high sensitivity characteristics, and its industrial value is extremely large.

[Brief explanation of drawings]

Figure 1 is a curve diagram showing the sensitivity depending on the bisazide/diazo ratio, Figure 2 is a curve diagram showing the adhesive force depending on the bisazide/diazo ratio, and Figure 3 is a curve diagram showing the adhesive force depending on the PVP/PVA ratio when the bisazide/diazo ratio is constant. The curve diagram shown in Figure 4 is for constant bisazide/diazo
FIG. 3 is a curve diagram showing cracks and unevenness due to PVP/PVA. 21, 22, 23, 24...characteristic curves.

Claims (1)

[Scope of Claims] 1. A step of forming a photoresist film made of a water-soluble bisazide compound, a water-soluble diazo compound, and a water-soluble polymer material on the inner surface of the face panel;
a step of curing a specific portion of the photoresist film by exposure using a shadow mask; a step of removing the unexposed portion of the photoresist film by development to form dots of the photoresist film; and a step of forming dots of the photoresist film, and the face panel after development. A pattern forming method comprising the steps of: coating the entire inner surface with a non-luminescent light-absorbing material coating; and forming holes in the dots and the non-luminescent light-absorbing material coating on the dots. 2. The water-soluble polymer material is a mixture of polyvinylpyrrolidone and polyvinyl alcohol, and the weight ratio of the polyvinylpyrrolidone to the polyvinyl alcohol is in the range of 0.5 to 3.0, and the water-soluble bisazide compound is a water-soluble diazo The compounding ratio to the compound is 3.0 or more by weight
7.0 range, the pattern forming method according to claim 1.