Process for manufacturing printed wiring board using metal plating techniques

A process for producing a printed wiring board, which comprises the steps of:

• (1) forming a first insulator layer having a first through-hole on a substrate, the first through-hole penetrating in a thickness direction of the first insulator layer;
• (2) forming a conducting passage through the first through-hole by plating with metal so as to deposit up to substantially a same level as an upper surface of the first insulator layer thus forming an even upper surface;
• (3) forming a thin metal film on the first insulator layer and the conducting passage so that the thin metal film has an almost flat surface and lacks unevenness;
• (4) forming a conductor layer in a prescribed circuit pattern on the thin metal film by plating so that the conductor layer has an almost flat surface and lacks unevenness;
• (5) removing a portion of the thin metal film on which the conductor layer is not formed;
• (6) forming a second insulator layer on the conductor layer;
• and
• (7) removing the substrate.