MULTILAYER PRINTED WIRING BOARD AND MANUFACTURE THEREOF

摘要

PROBLEM TO BE SOLVED: To prevent undercuts by forming a second insulation layer contacted to second conductor circuits on a first insulation layer contacted to first conductor circuits so that the photosetting depth of the first insulation layer is greater than that of the second one and roughening rate of the second insulation layer is higher than that of the first one. SOLUTION: On the top surface of an inner layer printed wiring board 6 inner layer circuit conductors 7a of first conductor circuits and hardened dry film resist 8b to be a first insulation layer are formed. On the resist 8b a photosensitive insulative resin 11 is applied as a second insulation layer and hardened to form an insulation resin 11a. Vias 13 composed of vias 10, 12 are formed, a conductor layer 14 is formed as a second conductor circuit. The resins are selected so that the photostatting depth of the dry film resist 8b is greater than that of insulative resin 11 and roughening rate of the resin 11 is higher than that of the resist 8b.