| 摘要 |
PROBLEM TO BE SOLVED: To prevent the surface insulating resistance from being degraded due to absorption of humidity by etching copper foil of an outer layer to form a conductor circuit and thereafter cleaning the surface of the exposed layer of resin composition in nitric acid. SOLUTION: An insulating layer 1 is dissolved to expose a pattern 2 and form very small holes 4, and the inner layer panel is immersed to rough the surface of the insulating layer 1 and form anchors on the surface. The panel is annealed by electroless nickel plating, and plating 5 is given using electrolytic copper plating to form plating BVH 7 without pin holes, which is then baked. Subsequently, etching resist is applied to the panel with the BVH 7 formed thereon, and unnecessary copper is removed. After cleaning with a solution prepared by diluting concentrated nitric acid with pure water, films are stripped off to obtain a buildup multilayer printed wiring board having the BVH 7. Thereby degradation in surface insulating resistance due to contact with palladium can be prevented. |
