Nippon Paint Compnay, Ltd.

Yoshikazu Yamagami

Akio Kashihara

Hisaki Tanabe

Mamoru Seio

Kiyomi Sakurai

Shinji Seo

Mitsuo Yoshioka

A method of producing multilayer circuit boardschar comprising repeating a procedure comprising the steps of (1) laminating a photosensitive film composition shaped in a film form onto an insulating material carrying a conductor pattern formed thereon, (2) exposing the laminated photosensitive film composition to light through a negative type photomask, (3) dissolving the domains not irradiated in the above exposure step, (4) heat-curing the domains not dissolved in step (3), (5) forming a copper plating layer on the surface of the photosensitive film composition heat-cured in step (4) by electroless copper plating with or without further electroplating of copper, and (6) forming, on the plated copper layer formed in step (5), a photosensitive etch resist layer and subjecting said layer to light exposure through a photomask having a circuit pattern drawn thereon, developing and etching to thereby form a conductor pattern, said photosensitive film composition for lamination containing at least 50% by weight of a bisphenol-epichlorohydrin type resin containing photosensitive functional groups and heat-curable functional groups.

Method of producing multilayer circuit boards

The present invention provides an improved method for forming a patterned solder mask having preferred electric insulating property, heat resistance-and chemical resistance on a printed circuit board with high resolution.

Method for forming patterned solder mask

The present invention has as its object providing a solder mask which permits high density mounting, is suitable for protecting conductor circuits, particularly has mask thickness on the circuit parts and each edge part of the circuits which make almost no difference from those on other parts, and is excellent in electrical insulation, heat resistance and solvent resistance. This invention provides a method of forming a solder mask for printed circuit boards, using any powder paint which is curable by both irradiation of ultraviolet ray and heat, comprising:

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Neyagawa, Japan

Yoshikazu Yamagami