Birch, Stewart, Kolasch & Birch
Method for producing printed circuit board using photocurable resin laminate
 Method for producing printed circuit board using a photocurable resin laminate comprising a support and a photocurable resin layer disposed on one surface of said support, said photocurable resin layer having: PA1 (a) a viscosity of from 10.sup.4 to 5.times.10.sup.5 poises as measured at 90.degree. C.; PA1 (b) a thickness of from 30 to 150 .mu.m; and PA1 (c) an ultraviolet ray transmittance of from 40 to 95% with respect to ultraviolet rays having a wavelength of 365 nm. When this photocurable resin laminate is laminated under pressure on both surfaces of a metal-clad insulting base board having through-holes of an inner diameter smaller than 0.5 mm so that both surfaces of the metal-clad insulating base board are covered with the photocurable layer of the photocurable resin laminate, the photocurable resin layer intrudes locally in the inner side of the inner circumferential edge of both terminal openings of each through-hole and extends from the inner circumferential edge along and on the inner wall of the through-hole to a predetermined depth. By the light exposure of such a laminate structure and the subsequent development, both terminal openings of each through-hole can be completely covered with a photocured resin layer without occurrence of coverage failure, wherein a photocured resin layer adhering to the inner wall of the through-hole is formed in the through-hole from the inner circumferential edge of the terminal opening thereof along and on the inner wall of the through-hole. 
Asahi Kasei Kogyo Kabushiki Kaisha
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Jiro Toru Hideki
Sato Mori Matsuda