JPS6410055B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an image forming material in which a photopolymerizable composition layer containing a specific photopolymerization initiator and an adhesion improver is provided on a transparent support. An image for release development that can provide a precision image with good adhesion and adhesion of the exposed portion to the substrate by peeling off the support after exposure and heat treatment if necessary. It concerns the forming material. Conventionally, solution-type photoresists and film-type photoresists have been commercially available for use in producing printed wiring boards, but these both utilize the difference in solubility in the solution between exposed and unexposed areas. It formed an image. However, in recent years, the operation of using a developer has become complicated, and the use of a developer has the potential to cause waste fluid to harm public health.
No. 38-9663, Special Publication No. 1972-22901, Japanese Patent Publication No. 1973-
No. 7728, Japanese Patent Publication No. 48-43126, Japanese Patent Publication No. 47-33623
Peelable and developable image forming materials and image forming methods as described in Japanese Patent Publication No. 51-48516, Japanese Patent Publication No. 40537, Japanese Patent Publication No. 53-19205, and Japanese Patent Publication No. 53-35722. is proposed. These methods utilize the difference in adhesive strength between the exposed and unexposed areas to the base material and the support to form an image by peeling. Although relatively thin photopolymerizable composition layers with easy to cut interfaces can produce somewhat satisfactory images, they are not suitable for use as etching resists (referred to as tenting resists) used, for example, when etching through-hole copper substrates.
In this case, the through-hole area must be covered with a resist that can withstand the spray pressure of the etching solution, so the resist film that covers the through-hole area must have sufficient film strength. Although it is necessary to increase the thickness to some extent, the present situation is that no satisfactory tenting resist has yet been obtained, which requires a relatively thick photopolymerizable composition layer. When etching a through-hole copper board,
Since it is necessary to withstand the spray pressure of the etching solution, the resist film covering the through-hole portion must have strength and elongation. Image-forming materials that can be developed with organic solvents or alkaline aqueous solutions use a method in which the portions that are cured by exposure remain on the substrate, and the unexposed portions are dissolved and removed by the developer. For,
The adhesive strength between the photopolymerizable composition layer and the base material can be made sufficiently large in advance, and there is little problem with peeling of exposed areas during development. However, when forming an image by peeling, it is necessary to easily peel off the unexposed areas, so it is not possible to increase the adhesive strength between the photopolymerizable composition layer and the base material sufficiently in advance. Therefore, only the exposed areas are required to have very high practical adhesion to the substrate (adhesion that can resist peeling, tension, shear scratching, etc.). In particular, when used as a tenting resist, it is necessary to increase the film thickness of the resist to provide film strength, but the thicker the film, the more difficult it is to cut the interface between the exposed and unexposed parts. At the same time, a large force is applied during peeling, so even if the exposed portion has a certain degree of adhesion to the substrate, the exposed portion tends to peel off during peeling, such as when the adhesive area with the substrate is small. In particular, the photopolymerizable composition layer, which is made to have extremely good elongation in order to obtain a tough film, tends to have a relatively small modulus of elasticity in the exposed area, and the unexposed area is peeled off along with the support. As the exposure progressed, the exposed portions tended to deform. An object of the present invention is to easily peel off the photopolymerizable composition layer in the unexposed parts of an etching resist in which the resist film covering the through-hole part has excellent elongation so as to sufficiently withstand the spray pressure of the etching solution. is possible, and during peeling development,
The object of the present invention is to provide a peelable and developable image forming material that has excellent adhesion and does not peel off even in exposed areas with a very small adhesive area. As a result of extensive studies to overcome the shortcomings of the prior art in line with the above objectives, the present inventors have developed a compound having a film-forming polymeric substance and at least one addition-polymerizable unsaturated bond on a transparent support. In an image forming material provided with a photopolymerizable composition layer containing a photopolymerization initiator as an essential component, the photopolymerization initiator has the general formula (However, R ₁ is OX in the H region, and X is CH ₃ or C ₂ H ₅ ,
For R ₂ , a compound represented by OCH ₃ , OC ₂ H ₅ , OC ₃ H ₇ or OC ₄ H ₉ ) is used, and as an adhesion improver, a compound represented by the general formula (However, R ₃ is a substituted or unsubstituted aromatic residue or heterocyclic compound residue, R ₄ is a halogen or
By adding a compound represented by CHmYn (“Y is halogen, m+n=3, n is 1 or more”) in a range of 0.01 to 5% by weight based on the total amount of the photopolymerizable composition (solid content), Excellent adhesion (i.e., the exposed area does not easily peel off from the substrate during peel development)
It was discovered that this material can be used as an image forming material, leading to the present invention. Examples of the compound represented by the general formula (A) used in the present invention include benzoin methyl ether, benzoin ethyl ether, benzoin (iso)propyl ether, benzoin (iso) butyl ether, benzyl dimethyl ketal, and benzyl diethyl ketal. Further, examples of the compound represented by the general formula (B) include compounds having the following structural formula.

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[Formula] etc. Therefore, various compounds have been known as photopolymerization initiators generally used in image forming materials, but the compound of the above general formula (A) is different from the compound of the general formula (B). A major feature of the present invention is that the adhesion to the image forming substrate is improved by using it in combination with. According to the experiments conducted by the present inventors, even if Compound B is added to Compound A in a photopolymerizable composition for image formation, the phenomenon of accelerating the photopolymerization rate and improving the reaction rate is not observed. It has been confirmed that the adhesive strength of the exposed portion to the substrate is the same regardless of the presence or absence of Compound B, and that almost no photopolymerization reaction occurs with Compound B alone. Incidentally, although the reason for the improved adhesion of the exposed area to the base material in the present invention is not clear, most of the compound A acts as an original photopolymerization initiator, but a part of it acts to activate compound B. , hydrogen halide is generated from the halogen radicals emitted from compound B, and by activating the surface of the substrate (for example, a copper-clad laminate for printed wiring boards), the adhesion and adhesion of the exposed area are improved and peeling is facilitated. It is presumed that this will be prevented. However, there are restrictions on the amount of compound B added, which is 0.01 to 5% relative to the total amount of photopolymerizable composition (solid content).
It is necessary to add it within a range of % by weight. If the amount added is less than 0.01% by weight, a sufficient effect to improve adhesion cannot be obtained, while if it is more than 5% by weight, the effect of improving adhesion can be obtained, but the physical properties such as cohesive force of the photopolymerizable composition layer This is not desirable because it changes the image quality and reduces the accuracy of the image. The photopolymerization initiator represented by the compound A is
It is preferable to use it in a range of 0.1 to 20 parts by weight. To explain other materials constituting the image-forming material of the present invention, the transparent support has good transmittance to light in the wavelength range of 300 to 500 nm that can photopolymerize the photopolymerizable composition layer, and has a surface. Those that are uniform are selected. Specific examples of such supports include polyethylene terephthalate, polypropylene, polyethylene, cellulose triacetate, cellulose diacetate, polyvinyl chloride, polyvinyl alcohol, polycarbonate, polystyrene, cellophane, polyvinylidene chloride copolymer, polyamide ( For example 6-
Various types of plastic films can be used, such as nylon, 6,6-nylon, 6,10-nylon, etc.), polyimide, vinyl chloride-vinyl acetate copolymer, polytetrafluoroethylene, and polytrifluoroethylene. Furthermore, a composite material consisting of two or more of these types can also be used. The support generally has a thickness of 10 to 150 μm, preferably 20 to 50 μm, but supports having a thickness outside the above range can also be used. The film-forming polymeric substance that can be used in the present invention can be selected from a wide variety of polymeric substances, but those that have extremely poor compatibility with other constituents are not preferred. Examples of preferred film-forming polymeric substances include:
Chlorinated polyolefins (e.g. chlorinated polyethylene, chlorinated polypropylene), polymethyl methacrylate, polymethyl acrylate, polyvinyl chloride, polyvinylidene chloride, polyvinyl butyral, polyvinyl acetate, vinyl chloride.
Vinyl acetate copolymer, vinylidene chloride-acrylonitrile copolymer, polyisoprene, chlorinated rubber,
Examples include polychloroprene, polychlorosulfonated ethylene and polychlorosulfonated propylene, and solvent-soluble linear saturated polyesters. Two or more of these polymeric substances can be used in combination. The compound having at least one addition-polymerizable unsaturated bond used in the present invention includes a wide range of addition-polymerizable compounds. Examples include acrylic esters, acrylamides, methacrylic esters, methacrylamides, allyl compounds, vinyl ethers, vinyl esters, N-vinyl compounds, styrenes, crotonic esters, and the like. Specific examples of compounds having one addition-polymerizable unsaturated bond include acrylic esters, such as acrylic acid, alkyl acrylates (such as propyl acrylate, butyl acrylate, amyl acrylate, ethylhexyl acrylate, octyl acrylate). ), methacrylic esters, such as methacrylic acid, alkyl methacrylates (such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate),
Acrylamides, such as acrylamide, N-
alkylacrylamide, (such alkyl groups include, for example, methyl, ethyl, butyl, isopropyl, t-butyl, ethylhexyl, etc.), methacrylamide, such as methacrylamide, N-alkylmethacrylamide ( Examples of the alkyl group include methyl group, ethyl group, isopropyl group, t-butyl group, and ethylhexyl group), allyl compounds such as allyl esters (such as allyl acetate, allyl caproate, allyl caprylate, and lauric acid) allyl, allyl palmitate), vinyl ethers such as alkyl vinyl ethers (e.g. hexyl vinyl ether, octyl vinyl ether, decyl vinyl ether, ethylhexyl vinyl ether),
Vinyl esters such as vinyl butyrate, vinyl isobutyrate, vinyl trimethyl acetate, vinyl diethyl acetate, vinyl valerate, vinyl caproate, and the like. Other styrenes include styrene, methylstyrene, chloromethylstyrene, alkoxystyrene, halogenated styrene, and styrene benzoate. Examples of crotonate esters include methyl crotonate, ethyl crotonate, butyl crotonate, hexyl crotonate, and isopropyl crotonate. Next, specific examples of compounds having two or more addition-polymerizable unsaturated bonds are illustrated, and these are more preferably used than the above-mentioned compounds having one addition-polymerizable unsaturated bond. First, acrylic esters and methacrylic esters include polyacrylates and polymethacrylates (herein, "poly" refers to diacrylate or higher) of polyhydric alcohols. The polyhydric alcohol mentioned above is
Polyethylene glycol, polypropylene oxide, polybutylene oxide, (β-hydroxyethoxy)benzene, glycerin, diglycerin,
Neobentyl glycol, trimethylolpropane, triethylolpropane, pentaerythritol, dipentaerythritol, sorbitan, sorbitol, 1,4-butanediol, 1,2,
4-butanetriol, 2-butene-1,4-diol, 2-butyl-2-ethyl-propanediol, 2-butene-1,4-diol, 1,3-
Examples include propanediol, triethanolamine, decalindiol, 3-chloro-1,2-propanediol, and the like. In addition, oligoester acrylate, oligoester methacrylate, epoxy acrylate,
Acrylates and methacrylates commercially available under names such as urethane acrylate can also be suitably used. Two or more kinds of such compounds having at least one addition-polymerizable unsaturated bond can also be used in combination. These compounds are film-forming polymeric substances.
It is used in an amount of 10 to 500 parts by weight, preferably 30 to 200 parts by weight per 100 parts by weight. The photopolymerizable composition layer of the image forming material of the present invention is composed of the film-forming polymeric substance, addition polymerizable unsaturated compound, specific photopolymerization initiator, and adhesion improver as described above. In addition, various additives such as thermal polymerization inhibitors, colorants, fillers, and plasticizers can be added as necessary. Each material constituting the photopolymerizable composition layer used in the present invention is dissolved in a solvent to form a coating solution, which is coated onto a support and dried. Solvents for the coating solution include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, aromatic hydrocarbons such as toluene, benzene, and xylene, esters such as ethyl acetate, butyl acetate, and amyl acetate, carbon tetrachloride, chloroform,
Examples include halogenated hydrocarbons such as trichloroethylene and methylene chloride, ethers such as diethyl ether, tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, dimethylformamide, and dimethyl sulfoxide. The photopolymerizable composition layer has a thickness of 5 to 100 μm, preferably 10 μm after coating the coating solution on the support and drying it.
Provided so that the thickness is ~60 μm. The image forming material of the present invention has a structure in which a photopolymerizable composition layer is provided on a support, but a protective film can also be provided on the photopolymerizable composition layer if necessary. As the protective film, polyethylene, polypropylene, various films treated with non-adhesive treatment, paper, etc. can be used. To explain the method of forming an image using the image forming material of the present invention, if the image forming material has a protective film, the protective film is peeled off and then the photopolymerizable composition layer is pressure-bonded to a desired substrate. The image is then exposed through the transparent support. As the light source, a light source containing light with a wavelength in the range of 350 to 500 nm, such as a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a carbon arc lamp, etc., can be used. In addition, laser beams, electron beams, X-rays, etc. may be used as the light source. After image exposure,
Heat treatment may be added if necessary (50℃~120℃)
℃ for about 1 minute to 120 minutes), when the support is peeled off from the substrate, the exposed portion in the image exposure is cured and remains on the substrate, and the unexposed portion is removed together with the support without being cured, thus forming the desired image on the substrate. is formed. When the image-forming material of the present invention is used as a so-called tenting resist with a thick photopolymerizable composition layer, the cured portion has good adhesion to the substrate, so that it provides an image free from defects due to peeling. Although it is conveniently used, it can of course also be suitably used for producing other resist images not intended for tenting. Furthermore, it can also be used for the production of printing plates such as planographic printing and letterpress printing, and the production of other relief images. The present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples. Example 1 Chlorinated polyethylene (Super Chron CPE907LTA manufactured by Sanyo Kokusaku Pulp Co., Ltd.) 80 (parts by weight) Polymethyl methacrylate (Dyanal BR-80 manufactured by Mitsubishi Rayon Co., Ltd.) 20 Pentaerythritol acrylate 40 Oligoester acrylate (Juiasei Kagaku Kogyo Co., Ltd.) Aronix M-6100) 100 Benzoin isobutyl ether 7.0 2-naphthalene sulfonyl chloride 1.0 Paramethoxyphenol 0.1 Victoria Pure Blue 0.3 Toluene 400 A solution of the photopolymerizable composition was prepared by uniformly dissolving and mixing the above materials. . Spread this liquid to a thickness of 25μ
It was coated on a polyethylene terephthalate film of 400 mL to a thickness of 40 μm after drying, and heated at 80°C.
An image forming material was obtained by drying for 10 minutes. Next, this image forming material was laminated under pressure on both sides of a double-sided copper-clad substrate for a printed wiring board having through holes whose surface had been cleaned. In this state, the negative original with the wiring circuit pattern was brought into close contact with the support of the image forming material laminated on the copper surface, and the negative original was exposed to light for 25 seconds from a distance of 60 cm using a 3KW ultra-high pressure mercury lamp. (Both sides of the board are exposed).
Next, when the substrate is heated to 35°C and the polyethylene terephthalate film support is peeled off from the substrate, the exposed portions of the photosensitive layer harden and remain on the copper-clad substrate, and the unexposed portions are coated with the support. It was removed from the copper-clad substrate, and a positive original image corresponding to the negative original was formed on the copper-clad substrate. The resist pattern formed in this way faithfully reproduces the negative original (resolution down to a fine line of 125 μm), but there are some defects such as the exposed part peeling off from the substrate and the image being disconnected or missing.
Also, there were no defects such as tearing of the tenting part. Similar operations were performed on nine more substrates, and resist patterns with no defects were similarly obtained. The copper layer of the copper-clad substrate having the resist pattern thus obtained was etched at a temperature of 40°C using a cupric chloride aqueous solution, but the photosensitive layer remained intact during this etching process. It was confirmed that it adheres strongly to copper and that no phenomena such as peeling, generation of pinholes, or tearing of the tenting part occurred at all. Further, the photosensitive layer after etching could be easily peeled off from the substrate using methylene chloride. Further, when the sensitivity of this image forming material was examined using a PS step guide manufactured by Fuji Photo Film Co., Ltd. under the above exposure conditions, a number of development steps of 9 was obtained. Comparative Example 1 Example 1 except that 2-naphthalenesulfonyl chloride in the photopolymerizable composition of Example 1 was removed.
An image forming material was obtained in the same manner as described above. Resist pads were formed on 10 substrates by the same operations as in Example 1 using the same substrates and negative originals as in Example 1. If you look at these 10 cards, 1 in 2
It was confirmed that disconnection defects due to the exposed portion peeling off from the substrate occurred in approximately 100% of the substrates. However, the subsequent etching process did not cause the resist pattern to peel off further and the number of defective areas did not increase. Note that this image forming material is Example 1.
It was confirmed that a 125 μm image was resolved in the same way as in the previous example, and the sensitivity was 9 steps with the PS step guide. Example 2 Chlorinated polyethylene (Super Chron CPE907HA manufactured by Sanyo Kokusaku Pulp Co., Ltd.) 70 (parts by weight) Polymethyl methacrylate (Dyanal BR-83 manufactured by Mitsubishi Rayon Co., Ltd.) 30 Trimethylolpropane triacrylate 40 Oligoester acrylate (Toagosei Chemical Co., Ltd.) Aronix M-6300 manufactured by Kogyo Co., Ltd.) 100 Benzyl dimethyl ketal 4.0 Tripromomethylphenylsulfone 0.5 Paramethquine phenol 0.1 Victoria Pure Blue 0.3 Toluene 400 A solution of the photopolymerizable composition is prepared by uniformly dissolving and mixing the above materials. Then, apply this liquid to a thickness of 25 μm.
It was coated on a polyethylene terephthalate film so that the thickness after drying was 40 μm, and it was heated at 80℃ for 10 minutes.
An imaging material was obtained by drying for a minute. This material was laminated on 10 substrates similar to those in Example 1, and exposure was carried out in the same manner as in Example 1, except that the same negative original was used and the exposure time was 20 seconds.
Next, peeling development was performed, but no defects such as peeling were observed in the resulting resist pattern. It was also confirmed that no problem occurred even if the etching treatment was performed. The resolution of this material was 125 μm, and the sensitivity under the above exposure conditions was 8 steps with a PS step guide. Example 3 Chlorinated polyethylene (Superchron CPE907LTA manufactured by Sanyo Kokusaku Pulp Co., Ltd.) 100 (parts by weight) Oligoester acrylate (Aronix M-8060 manufactured by Toagosei Chemical Industry Co., Ltd.) 70 Diethylene glycol diacrylate 70 Benzoin isopropyl ether 7.5 Para-toluenesulfonyl chloride 1.0 Paramethoxyphenol 0.1 Ether violet 0.3 Toluene 400 A solution of the photopolymerizable composition was prepared by uniformly dissolving and mixing the above materials, and this liquid was spread to a thickness of 25 μm.
It was coated on a polyethylene terephthalate film so that the thickness after drying was 50 μm, and it was heated at 80℃ for 10 minutes.
An imaging material was obtained by drying for a minute. Using this material, resist patterns were produced on 10 substrates using the same substrates, negative originals, and processing conditions as in Example 1. No defects such as peeling were observed in this resist pattern, and no problems occurred even during the etching process. The resolution of this material was 150 μm, and the sensitivity under the above exposure conditions was 9 steps with a PS step guide. Comparative Example 2 An image forming material was prepared in the same manner as in Example 2 except that 8 parts of benzyl was used in place of the benzyl dimethyl ketal in Example 2. A resist pattern was prepared using this material in the same manner as in Example 2, but it was confirmed that defects due to peeling of exposed areas occurred in about 1 out of 3 out of 10 substrates. I was caught. The resolution of this material was 125 μm, and the sensitivity was 7 steps using a PS step guide.

Claims (1)

[Claims] 1. A photopolymerizable composition layer containing a film-forming polymer substance, a compound having at least one addition-polymerizable unsaturated bond, and a photopolymerization initiator as essential components is provided on a transparent support. In the image forming materials consisting of (However, R ₁ is H or OX, and X is CH ₃ or C ₂ H ₅ ,
For R ₂ , a compound represented by OCH ₃ , OC ₂ H ₅ , OC ₃ H ₇ or OC ₄ H ₉ ) is used, and as an adhesion improver, a compound represented by the general formula (However, R ₃ is a substituted or unsubstituted aromatic residue or heterocyclic compound residue, R ₄ is a halogen or
CHmYn "Y is halogen, m + n = 3, n is 1 or more") is added in an amount of 0.01 to 5% by weight based on the total amount of the photopolymerizable composition (solid content). An image forming material that can be peeled off and developed.