JPS58174942A - Formation of photoresist - Google Patents

Abstract

PURPOSE:To obtain a clear resist image with etching resistance by applying an aqueous soln. of a mixture of polyvinyl alcohol resin contg. acetoacetic ester groups or allyl groups with a photoreaction accelerator to a substrate, exposing the resulting film to ultraviolet rays, and developing it with water. CONSTITUTION:A soln. contg. polyvinyl alcohol resin contg. 0.1-35mol% acetoacetic ester groups or allyl groups and <=35mol% residual acetic acid groups and having about 200-3,000 average degree of polymn. and a photoreaction accelerator such as benzoin alkyl ether or sodium anthraquinone-beta-sulfonate is prepared. The soln. is applied to the surface of a substrate such as a Zn or Al plate and dried to form a photosensitive film. A negative image is brought into contact with the film, and after exposure to ultraviolet rays, the unexposed part is removed by washing to obtain a clear resist image. The image is hardened, and a printing plate or the like with superior resolution is obtd. by removing the residual resist by treatment with an aqueous alkali soln.

Description

DETAILED DESCRIPTION OF THE INVENTION It is well known that cinnamate ester of polyvinyl alcohol has photosensitivity, but since the resin is insoluble in water, Ktibenzene, which elutes the unsensitized portion after irradiating it with light, The use of organic solvents such as toluene, chlorobenzene, and trichlene is essential. However, the use of such organic solvents poses practical problems in terms of deterioration of the working environment, danger of making a fuss, and increased cost.

However, as a result of various studies, the present inventors found that polyvinyl alcohol-based resins containing acetoacetate groups or allyl groups are water-soluble unless UV irradiated, and on the other hand, when a polyvinyl alcohol film is irradiated with UV rays, only the irradiated parts become soluble. It has the property of being water-insoluble, and by utilizing this property to form a film of the resin on a base material and then irradiating it with ultraviolet rays through a negative direction, it becomes extremely sensitive and the exposed area becomes water-insoluble. It becomes insoluble, while the unexposed part remains water-soluble and can be easily removed by washing with water, j! After etching the base material, the water-insoluble acetoacetate group or allyl group-containing polyvinylalfur resin remaining on the base material is removed. The present inventors have discovered that washing with IFi alkaline water can provide remarkable effects such as easy removal, and have completed the present invention.

In the present invention, a clear photoresist image can be formed simply by using water without using a layer of organic solvent. This method can solve all problems such as uploading, and is extremely advantageous for practical application.

The polyvinyl alcohol resin having an acetoacetate group used in the present invention can be produced by any method, and there is no limitation to the production method. Obtained by transesterification. Similarly, a preferred method for producing allyl group-containing polyvinyl alcohol resin is a method in which a polyvinyl alcohol resin is reacted with an allyl compound such as allyl chloride or allyl bromide. As the base polyvinyl alcohol resin, in addition to partially or fully saponified polyvinyl esters such as polyvinyl acetate, vinyl acetate is used as a monomer, and other copolymerizable hexamers such as unsaturated carboxylic acids or Part or complete ester, salt, anhydride, amide, nitrile, unsaturated sulfonic acid or its salt, carbon number 2-50
"Copolymerization modification" in which copolymers with α-olefins, vinyl ethers, etc. are saponified, and "post-modification" in which polyvinyl alcohol and polyvinyl alcohol are acetalized, cretacylated, etherified, grafted, phosphoric acid esterified, etc. Polyvinyl ercolmo may be used.

The content of the acetoacetate group or allyl group in the above resin can be 0.05 mol% or more, up to the maximum within the range of water solubility, but it is usually FiO, 1 to 55 mol%, especially 0.2 mol%. It is often selected from the range of ~60 mol%. If the content of acetoacetate groups or allyl groups is too high, water insolubilization by ultraviolet irradiation will not be sufficient and a satisfactory photoresist image will not be obtained. Introduction of more acetoacetate groups or allyl groups than necessary makes KFi insoluble in water, which is inappropriate for the purpose of the present invention.

Or average degree of polymerization Fi200-5000 preferably 500
It is preferable to select from the range of ~2000 W &# of acetic acid groups present - 155 mol % or less, preferably Fi 30 mol 96 or less.

A photoreaction accelerator is used in combination with such acetoacetate group- or allyl group-containing polyvinyl alcohol resin.

As photoreaction accelerators, benzoin alkyl ethers such as benzoin methyl ether, benzoin ethyl ether, and pensiidiisofurohyl ether, organic iodine compounds such as dibutyl sulfide, benzyl sulfide, and decylphenyl sulfide, diazonicum salts, tetoxonicum salts, or combinations thereof Complex salts with zinc chloride or their condensates, azobisisobutyronitrile, dyes such as methylene blue, or combinations thereof with p-toluenesulfonate ions, organic perhydrides, hydrogen peroxide, pyrillicum salts, or thiavirillicum. salt, ammonicum dichromium, acetophenone, benzophenone, hensyl, 7-enanthrene, thioxantho, cyclophenylketone, acitraquinone, 2-chloroanthraquinone, 2-
Bromoanthraquinone, anthraquinone β-sulfonic acid sodium, 1,5-dinitroanthraquinone, 1,2-benzonthraquinone, phenanthrenequinone, 5-benzoylacenaphthene, 5-nitroacenaphthene, 1.4-
7-toquinone, 1.8-7-taroylnaphthalene, 2-nitrofluorene, p-nitroaniline, picramide, benzaldehyde, etc.
Two or more types are used in combination.

Not limited to those listed above, reactions by light, cross-linking,
Any substance that promotes polymerization can be used. Among these, benzoin alkyl ether and acitraquinone β-sulfonic acid sodium are particularly effective in terms of price and sensitivity.
, gives ugly results.

In carrying out the method of the present invention, a mixture of the acetoacetate group-containing or allyl group-containing polyvinyl alcohol resin as described above and a photoreaction accelerator is applied to a substrate in an aqueous solution state, and the mixture is dried or preliminarily applied to the acetoacetate group. A film is produced by any method from a mixed solution of a group- or allyl-containing polyvinyl alcohol resin and a photoreaction accelerator, and the film is adhered to a substrate. In this case, there is no problem if it contains some amount of *g agent. Also, metal salts, aldehydes, amines, etc.
Known waterproofing agents such as IK, #i, various water-soluble polymers, and photoelectrically polymerizable monomers may be used in combination. The resin concentration in the aqueous solution is usually determined at Fit~2 from the viewpoint of workability when coating the base material and the use of the resulting photoresist image.
It is selected from a range of approximately 0% by weight. Film thickness tit~
Approximately 10μ is appropriate. As the base material, zinc plates, aluminum plates, magnesium plates, steel plates, copper plates, etc. are usually used.

Using the coated plate obtained in this way, by irradiating it with ultraviolet rays through the negative screen, the exposed areas become water-insoluble, while the unexposed areas remain water-soluble, so if you wash it with water, only the unexposed areas will be removed. removed. As a light source, a #i low-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, carbon arc lamp, xenon lamp, etc. are used. Then, for purposes such as letterpress printing, intaglio printing, and printed wiring, it is necessary to form this image and etch the substrate to corrode the exposed metal parts.

The etching agent may be appropriately selected depending on the substrate used. Typical etching agents include chlorides such as ferric chloride or cupric chloride, peroxides such as ammonium persulfate and hydrogen peroxide, acid groups such as sulfuric acid and hydrochloric acid, and alkalis such as sodium hydroxide. One example is the system.

Incidentally, by subjecting the base material to a hardening treatment prior to etching, the corrosion caused by etching can be carried out more precisely.

When using a polyvinyl alcohol-based photosensitizer, such hardening treatment is usually carried out using, for example, chromic anhydride, but for polyvinyl alcohol-based resins containing acetoacetate groups or allyl groups, the amount used must be It can be significantly reduced compared to modified polyvinyl alcohol, which is one of the characteristics of the acetoacetate group- or allyl group-containing polyvinyl alcohol resin used in the present invention. Representative examples of metal salts include chlorides, bromides, nitrates, sulfates, and acetates of polyvalent metals such as aluminum, iron, copper-1zinc, tin, titanium, nickel, antimony, magnesium, and chromium. Specific examples include cupric chloride, aluminum chloride, ferric chloride, tin chloride, zinc chloride, nickel chloride, magnesium chloride, aluminum sulfate, steel acetate, and chromium acetate. Mourning is not limited to these. Particularly preferred salts are ferric chloride, magnesium chloride, nickel chloride, and the like.

Examples of ammonium salts include organic acid ammonium salts such as ammonium chloride, ammonium sulfate, ammonium nitrate, and ammonium electrochromate, and ammonium salts of organic acids such as ammonium acetate and ammonium propionate. These metal salts and ammonium salts can be used alone or in combination.

Hardening properties The base material obtained as described above is appropriately treated with Kinho salt or ammonium salt solution by squirting, coating, dipping, etc., followed by drying and, if necessary, heat treatment. It is done *by doing.

Furthermore, after etching is completed, the resin remaining on the base material is removed. The acetoacetate group- or allyl group-containing polyvinyl alcohol resin used in the present invention has the property of being easily dissolved in alkaline water even after photo-crosslinking and becoming water-insoluble. Cleaning may be performed with an alkaline aqueous solution such as sodium chloride, aqueous ammonia, or the like.

In the case of polyvinyl alcohol-based resins conventionally used for photoresists, there is a problem in that it is not always easy to remove the resin after photocuring by washing with alkaline water, but the present invention completely eliminates this problem. It has characteristics.

Hereinafter, the method of the present invention will be explained in more detail by giving examples. Parts are based on weight unless otherwise specified.

Example 1 A 1596 aqueous solution of acetoacetate group-containing polyvinyl alcohol having an acetoacetate group content of 25 mol%, a residual acetate group of 1 mol%, and an average degree of polymerization of 500 was prepared, and benzenediazonicum clozide 5@ was further added to this. Mix and round.

Applying the insoluble solution uniformly onto a zinc plate using a rotating applicator,
After drying to form a film with a thickness of 5 μm, a line drawing negative was placed in close contact with the film and irradiated with ultraviolet rays for 5 minutes using a 400W low-pressure mercury lamp kept at a distance of +5011, followed by washing with water to form an image on the zinc plate. . Next, hold the obtained image plate for about 50 seconds @
The plate was immersed in a 2s * chromic acid aqueous solution, burnished for about 50 seconds, then subjected to Guku type etching to further oxidize the remaining resin with 596 hydroxyl.) When the remaining resin was removed by washing with an IJ Kuku aqueous solution, a good printing plate was obtained. Resolution Fi when printing using the plate
The number of lines per inch was 200.

The above 1596 aqueous solution was prepared, and the aqueous wave was applied onto a glass plate and dried to form a film with a thickness of 40μ.Then, using a 400W pressurized mercury lamp, the distance between the film and the light source was reduced to 1.
It was irradiated with ultraviolet rays for 6 minutes while maintaining the temperature at 5c*, and then thoroughly washed with water. When the photosensitivity at this time was expressed as a relative value of residual film yield and a 25-step gray scale manufactured by Eastman Kodak, the former was 170% and the latter was 15.

Example 2 A 10% aqueous solution of acetoacetate group-containing polyvinyl alcohol having an acetoacetate group content of 15 mol%, a residual acetate group of 5 mol%, and an average degree of polymerization of 1100 was prepared, and 4,4'-diazidostilbene was added to this. 5 parts of sodium -2,2'-disulfonate were mixed.

Apply the aqueous solution uniformly onto a zinc plate using a rotating applicator,
After drying to form a film with a thickness of 5 μm, a line drawing negative chip was placed in close contact with the film and irradiated with ultraviolet rays for 5 minutes using a 400Wi pressure mercury lamp kept at a distance of 151 cm, followed by washing with water to form an image on the zinc plate. . Next, the obtained image board is approximately 60 seconds 111
Immersed in 1104 aluminum sulfate aqueous solution, 50
After burning for a few seconds, the plate was subjected to Goku type corrosion and washed with alkaline water, and a good printing plate was obtained. Resolution Fi + number of lines per inch Fi + 80 when printing using this plate
Met. The relative residual film yield measured under the same conditions as in Example 1 was 95%, with a gray scale of 19. Examples 5 to 6 Experiments were conducted according to Example 2 under the conditions shown in Table 1. I did it. The results are shown in IIl Mugi.

Table 1 Example 7 Acetoacetate group-containing polyvinyl alcohol resin Allyl group-containing polyvinyl alcohol resin (denaturing device 15 mol%, residual acetate group 5 mol, average degree of polymerization +10)
The same method as in Example 2 was carried out using 0).

The number of streaks was 160, the relative residual film yield was 95 g6, and the gray scale was 18.

Claims (1)

[Claims] After forming a film made of a mixture of acetoacetate group- or allyl group-containing polyvinyl alcohol resin and a photoreaction accelerator on a substrate, it is irradiated with ultraviolet rays through a negative screen, and then the unexposed areas are washed away with water! A method for forming a photoresist characterized by etching a KM base material.