JP3120047B2 - Ultraviolet coloring sheet for alignment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultraviolet coloring sheet for aligning an exposure position of a liquid photoresist in manufacturing a printed circuit board.

[0002]

2. Description of the Related Art In the production of printed circuit boards, paper-
After forming a conductive circuit pattern by etching a substrate on which an insulating plate such as a phenolic resin plate or a glass-epoxy resin plate is bonded to a copper plate, make sure that solder is not attached to unnecessary parts in the subsequent soldering process. Conventionally, when a solder resist is formed, a method of forming a thermosetting or ultraviolet curing solder resist ink by screen printing has been the mainstream. However, with the recent fine patterning, it is difficult to secure the accuracy by screen printing, and thus the method is changing to a method using a liquid solder resist. This method applies a liquid solder resist on the entire surface of the substrate on which the conductive circuit pattern is formed,
This is a method of forming a solder resist portion by exposing only necessary portions and developing.

In the manufacture of such a printed circuit board, accurate alignment between a conductor circuit pattern and a solder resist pattern is very important. However, when a liquid solder resist is used, it is only necessary to expose the solder pattern. Since there is no discoloration due to exposure, the quality of the position cannot be confirmed, and it cannot be confirmed unless development is performed. Therefore, a lot of time is spent for positioning. In particular,
The formation of this conductor circuit pattern many times like a multilayer board,
When the formation of the resist layer is performed repeatedly, the number of unusable printed circuit boards increases in each process, and the loss rate is extremely high, especially for products manufactured in a small lot.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a positioning method having a good ultraviolet color-forming property which exhibits a sufficient contrast so that the positions of the conductor circuit pattern and the liquid solder resist pattern can be easily confirmed. An object of the present invention is to provide an ultraviolet coloring sheet.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies, and as a result, (A)
Leuco dye that develops a color by a photochromic compound or a photooxidant and a photooxidation reaction in one or more organic solvent soluble resins selected from polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinylpyrrolidone, ethylcellulose, methylcellulose or cellulose acetate. Is formed, the position of the conductive circuit pattern and the pattern of the liquid photoresist can be easily recognized, and an ultraviolet-coloring sheet capable of accurately setting the exposure position in a short time is obtained. Was found to be.

[0006] Further, on the ultraviolet coloring layer, (B) an acrylic adhesive or a rubber adhesive is coated with an ultraviolet absorber in an amount of 10 to 50 wt%.
By laminating the contained adhesive layer, in addition to the function of easily recognizing the misalignment between the conductor circuit pattern and the liquid photoresist pattern, the ultraviolet coloring sheet and the printed circuit board generated at the time of exposure due to the adhesive fixation can be used. The present invention has been found to eliminate loss due to misalignment, and simultaneously reduce loss due to curing of a liquid photoresist by absorbing ultraviolet light transmitted through an ultraviolet coloring sheet, and to perform alignment with a minimum manufacturing loss. It was completed. That is, in the present invention, on a transparent plastic film, (A) polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl pyrrolidone, ethyl cellulose, methyl cellulose or organic solvent soluble resin selected from cellulose acetate (A) photochromic compound Or, an ultraviolet coloring layer containing 1 to 50% by weight of a leuco dye which develops a color by a photooxidation reaction with a photooxidizing agent, and (B) an acrylic or rubber adhesive containing 10 to 70% by weight of an ultraviolet absorber. We have developed an ultraviolet coloring sheet for aligning the exposure of liquid photoresists, characterized by sequentially laminating adhesive layers.

As the transparent plastic film constituting the exposure alignment sheet of the liquid photoresist of the present invention, a polyethylene film, a polypropylene film, a nylon film, a polyester film or the like having a thickness of 10 to 100 μm, more preferably 30 to 80 μm is used. However, if necessary, a corona discharge treatment or a release treatment can be performed on one surface. Further, the ultraviolet coloring layer is a polyvinyl acetate, a vinyl chloride-vinyl acetate copolymer or an organic solvent-soluble resin selected from cellulose acetate, a photochromic compound, or a leuco dye that develops a color by a photooxidation reaction with a photooxidant in an amount of 1 to 50 wt. % Of the ultraviolet-ray-forming resin solution is applied to the support layer using a gravure printing machine, a reverse coater or the like. The thickness of this ultraviolet coloring layer is 0.5
The thickness is preferably from 50 to 50 .mu.m, but in consideration of the balance between the ultraviolet coloring performance and the cost, the thickness is preferably from 1 to 10 .mu.m.

The photochromic compounds used herein include 1,3,3-trimethylindolinobenzopyrrolospirane and 1,3,3-trimethylindolino-6 '
-Bromobenzopyrrolospirane, 1,3,3-trimethylindolino-8'-methoxybenzopyrrolospirane,
Spiropyran compounds such as 1,3,3-trimethylindolino-β-naphthopyrrolospirane, 1,1′-bis (2,4-dinitrophenyl) -4,4′-bipyridinium dichloride, 1,1′- Dibenzyl-4,4'-
Bipyridinium dichloride, 1,1'-di -n- f flop <br/>chill-4,4'-bipyridinium dibromide, 1,
Viologen compounds such as 1'-n-octyl-4,4'-bipyridinium dipromide and 4,4'-dibiridyl.

The leuco dyes include, for example, leuco crystal violet and leucomalachite green. Photooxidants that cause the leuco dye to develop color with ultraviolet light include, for example, benzophenone, 2,4,6-trimethylbenzophenone, benzophenone-based compounds such as 4-benzoyl-4′-methyldiphenylsulfide, 2,4-dimethylthioxanthone, and 2-benzophenone. Thioxanthone compounds such as isopropylthioxanthone, 2,2'-bis (-chlorophenyl) -4,5,
4 ', 5'-tetraphenyl-1,2-biimidazole and the like. The content of these ultraviolet coloring agents is 1 to 50% by weight. If the content is less than 1% by weight, a sufficient contrast cannot be obtained to easily recognize the positions of the conductor circuit pattern and the liquid photoresist pattern. If it exceeds, the coloring property is too high and the storage stability is poor. Considering economy, 1-30
It is preferable to add in the range of wt%. If necessary, a plasticizer of a binder resin may be added to the ultraviolet coloring layer.

The pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive or a rubber pressure-sensitive adhesive to which an ultraviolet absorber has been added, using a reverse coater or the like. The coating thickness is 1 to 20
μm is preferred. Also, if the peel strength between the substrate and the ultraviolet-coloring sheet is too high, peeling from the substrate after alignment becomes difficult, and the substrate cannot be used in the next step. Adhesive strength that can provide a peel strength of 10 to 200 gf / 50 mm to the paper-phenol resin substrate and the glass-epoxy resin substrate thus obtained is preferable. In order to obtain a suitable adhesive force that is easy to peel off, if necessary, inorganic particles such as silica, polyvinyl acetate, ethylene-vinyl acetate copolymer, polystyrene,
A resin such as a styrene-acrylic copolymer may be added.

There is no limitation on the ultraviolet absorber to be added to this adhesive, whether it is an inorganic ultraviolet absorber or an organic ultraviolet absorber.
As inorganic UV absorbers, titanium oxide, cerium oxide or zinc oxide, as organic UV absorbers, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxy Benzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy-4-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfo Xybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-
Sodium sulfonate, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-
Butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl ) -5-chlorobenzotriazole, 2- (2'-hydroxy
-3'-5'-t-butylphenyl) benzotriazole, phenyl salicylate, 4-t-butylphenyl salicylate,
4-t-octylphenyl salicylate, 2-ethylhexyl
-2-cyano-3,3'-diphenylacrylate or ethyl-
One or more compounds selected from the group of 2-cyano-3,3'-diphenylacrylate are used. The content of these ultraviolet absorbers is preferably 10 to 70 wt%, more preferably 20 to 60 wt%.
%. If the content is less than 10 wt%, the ultraviolet absorption is poor, and the ultraviolet light transmitted through the ultraviolet coloring sheet hardens the liquid photoresist. On the other hand, if it exceeds 70% by weight, the ultraviolet absorber itself is relatively expensive, which is not appropriate in terms of cost.

100 parts by weight of a vinyl chloride- vinyl acetate copolymer ("DENKA VINYL # 1000D" manufactured by Denki Kagaku Kogyo), 10 parts by weight of Leuco Crystal Violet ("LCV" manufactured by Hodogaya Chemical), dimethylthioxanthone ("KAYACURE" manufactured by Nippon Kayaku) A 5 μm reverse coater was applied to a 50 μm-thick biaxially stretched polyester film by a 5 μm reverse coater, and dried. The acrylic emulsion (central part) was made of 5 parts by weight of DETX, 200 parts by weight of ethyl acetate, and 200 parts by weight of toluene. 20 parts by weight of ethylene-
80 parts by weight of a vinyl acetate copolymer emulsion ("Lika Pond BE-800" manufactured by Chuo Rika Kogyo Co., Ltd.), 100 parts by weight of water, and an ultraviolet absorber ZnO ("White UV" manufactured by Resino Color)
-W-202 (solid content 30%) was coated with an adhesive prepared by adding 35 parts by weight of 7 μm and dried to prepare an ultraviolet coloring sheet. A liquid photoresist (“SPSR-700” manufactured by Sanwa Chemical Industry Co., Ltd.) is applied on a paper phenolic resin substrate on which a conductive circuit pattern is formed, and the produced ultraviolet coloring sheet is laminated thereon.
Exposure was performed for 60 seconds using a w metal halide lamp. The ultraviolet coloring sheet exhibited sufficient contrast so that the positional deviation between the conductor circuit pattern and the photoresist pattern could be easily identified without shifting from the paper phenolic resin substrate on which the conductor circuit pattern was formed during exposure. Also,
This ultraviolet coloring sheet could be easily peeled off from the paper phenolic resin substrate, and the liquid photoresist was not cured.

100 parts by weight of a vinyl chloride- vinyl acetate copolymer (“Denka Vinyl # 1000D” manufactured by Denki Kagaku Kogyo), 1 part by weight of 4,4′-dibiridyl (manufactured by Kishida Chemical),
An ultraviolet coloring resin solution comprising 200 parts by weight of ethyl acetate and 200 parts by weight of toluene was applied to a 50 μm-thick biaxially stretched polyester film by a 5 μm reverse coater and dried. Thereafter, 20 parts by weight of an acrylic emulsion ("Rica Pond AP-37" solid content 59% manufactured by Chuo Rika Kogyo Co., Ltd.) and an ethylene-vinyl acetate copolymer emulsion ("Rica Bond BE-800" solid content 56% manufactured by Chuo Rika Kogyo Co., Ltd.)
An adhesive prepared by adding 20 parts by weight of an ultraviolet absorber, sodium 2-hydroxy-4-methoxybenzophenone-5-sulfonate ("ASL-24ST" manufactured by Shonan Chemical Co., Ltd.), to 80 parts by weight and 100 parts by weight of water is applied at 10 μm. After drying, an ultraviolet coloring sheet was prepared. A liquid photoresist (“SPSR-700” manufactured by Sanwa Chemical Industry Co., Ltd.) is applied on a paper phenolic resin substrate on which a conductive circuit pattern is formed,
Laminate the ultraviolet coloring sheet made on it,
Exposure was performed for 90 seconds with a 3 kw metal halide lamp from a distance of 1 m. The ultraviolet coloring sheet exhibited sufficient contrast so that the positional deviation between the conductor circuit pattern and the photoresist pattern could be easily identified without shifting from the paper phenolic resin substrate on which the conductor circuit pattern was formed during exposure. Further, this ultraviolet coloring sheet could be easily peeled off from the paper phenol resin substrate, and the liquid photoresist was not cured.

[0014]

[Comparative Example 1] 100 parts by weight of vinyl chloride-vinyl acetate copolymer ("DENKA VINYL # 1000D" manufactured by Denki Kagaku Kogyo), Leuco Crystal Violet ("LCV" manufactured by Hodogaya Chemical) 10
Parts by weight, dimethylthioxanthone (KAYACU
RE DETX "5 parts by weight, ethyl acetate 200 parts by weight, toluene
200 parts by weight of an ultraviolet coloring resin solution was applied to a 50 μm thick biaxially stretched polyester film to a thickness of 5 μm with a reverse coater and dried to prepare an ultraviolet coloring sheet. Liquid photoresist (Sanwa Chemical Industries SP) on a paper-phenolic resin substrate with a conductive circuit pattern formed
SR-700 ") was applied thereon, and the ultraviolet coloring sheet prepared above was placed thereon, and exposed to a 3 kw metal halide lamp from a distance of 1 m for 90 seconds. The ultraviolet coloring sheet expresses enough contrast to easily identify the misalignment between the conductor circuit pattern and the liquid photoresist pattern, but has shifted from the resin plate at the time of exposure. Cured and could not be reused.

[0015]

[Comparative Example 2] Vinyl chloride - vinyl acetate copolymer (manufactured by Denki Kagaku Kogyo "Denkabini Le # 1000D") 100 parts by weight leuco crystal violet (Hodogaya Chemical Co. "LCV") 10 parts by weight, dimethyl thioxanthone (Nippon Kayaku UV-color-forming resin solution consisting of 5 parts by weight of “KAYACURE DETX”, 200 parts by weight of ethyl acetate, and 200 parts by weight of toluene was applied to a biaxially stretched polyester film having a thickness of 50 μm to a thickness of 5 μm by a reverse coater and dried. Thereafter, 20 parts by weight (solid content: 59% by weight) of an acrylic emulsion ("Licabond AP-37" manufactured by Chuo Rika Kogyo Co., Ltd.) and an ethylene-vinyl acetate copolymer emulsion ("Licabond BE-80" manufactured by Chuo Rika Kogyo Co., Ltd.)
0 ") An adhesive consisting of 80 parts by weight (solid content: 56% by weight) and 100 parts by weight of water was applied to a thickness of 5 μm and dried to prepare an ultraviolet coloring sheet. A liquid photoresist (“SPSR-700” manufactured by Sanwa Chemical Industry Co., Ltd.) is applied on a paper-phenol resin substrate on which a conductive circuit pattern is formed,
The above-prepared ultraviolet coloring sheet was laminated thereon, and exposed with a 3 kw metal halide lamp from a distance of 1 cm for 60 seconds. The ultraviolet-coloring sheet exhibited a sufficient contrast that the positional deviation between the conductor pattern and the fort resist pattern could be easily identified without shifting from the resin plate at the time of exposure. However, although this ultraviolet coloring sheet could be easily peeled off from the paper phenolic resin substrate, the liquid fort resist was cured and could not be reused.

[0016]

By using the exposure position adjusting sheet of the liquid photoresist according to the present invention described above, it is possible to prevent displacement from the printed circuit board at the time of exposure, and
The liquid photoresist is not hardened by the ultraviolet light transmitted through the sheet, the positional deviation between the conductive circuit pattern and the liquid photoresist pattern can be easily identified, and the exposure position can be accurately set in a short time without any loss.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI B41M 5/26 G03F 7/004 506 G03F 7/004 506 7/20 501 7/20 501 9/00 Z 9/00 H05K 3 / 00 G H05K 3/00 3/28 D 3/28 B41M 5/18 LE

Claims (2)

(57) [Claims] 1. A photochromic composition comprising: (A) one or more organic solvent-soluble resins selected from polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinylpyrrolidone, ethylcellulose, methylcellulose and cellulose acetate on a transparent plastic film. A compound or a leuco dye that develops a color by a photooxidation reaction with a photooxidant
(B) (i) an acrylic pressure-sensitive adhesive or (ii) a rubber-based pressure-sensitive adhesive,
An ultraviolet coloring sheet for exposure positioning, characterized by sequentially laminating an adhesive layer containing 70 wt%. 2. As an ultraviolet absorber, titanium oxide, cerium oxide, zinc oxide, 2,4-dihydroxybenzophenone, 2-hydroxyn-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy
-4-dodecyloxybenzophenone, 2,2'-dihydroxy -4-dimethoxybenzophenone, 2,2'-dihydroxy
-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfoxybenzophenone, 2-hydroxy-
Sodium 4-methoxybenzophenone-5-sulfonate,
2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'- Di-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-
(t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) benzotriazole, phenyl salicylate, 4-t-
At least one selected from the group consisting of butylphenyl salicylate, 4-t-octylphenyl salicylate, 2-ethylhexyl-2-cyano-3,3'-diphenylacrylate and ethyl-2-cyano-3,3'-diphenylacrylate 2. The ultraviolet-coloring sheet for exposure alignment according to claim 1, wherein the compound is used.