| 摘要 |
A process for the production of a high-density printed wiring board, comprising the steps of (1) providing an ultrathin-copper-foil-clad board having a hole and having an outermost copper foil thickness of 5 mum or less, plating the surface by electroless copper plating to form a layer having a thickness of 0.1 to 1 mum, (2) forming an electrolytic copper plating layer having a thickness of 0.5 to 3 mum by using the electroless copper plating layer as an electrode, (3) forming a plating resist layer on a necessary portion of the copper plating layer, (4) forming a pattern copper plating layer having a thickness of 6 to 30 mum on the copper surface in a portion where the plating resist layer is not formed, by electrolytic copper plating, (5) removing the plating resist layer, and (6) etching the entire surface to remove the thin electrolytic copper layer, the electroless copper layer and the ultrathin copper foil layer in at least a portion where the pattern copper plating layer is not formed.
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