Circuit board and process for producing the same

摘要

A circuit board comprising: a core material consisting of any one selected from the group consisting of magnesium, a magnesium alloy, and a magnesium-based composite material; and an electric circuit formed on the core material. A process for producing the circuit board comprises: forming an electrodeposition-painted coating on such a core material; forming a polyimide resin coating on the electrodeposition-painted coating; forming a viahole extending through the resin coating to the underlying electrodeposition-painted coating; etching and removing the electrodeposition-painted coating in the region exposed in the bottom of the viahole while masking the other region with the resin coating, to extend the viahole to the core material; forming a metal film at least on a free surface of the resin coating and a inner surface of the extended viahole; and etching the metal film by using a photoresist mask to form a conductor layer having a predetermined pattern.