Circuit board and its manufacture method

摘要

A protective agent 6 for protecting a wiring 1 is dispersed and placed in mottle-like on an interface between a via 3 and a wiring layer 2. Then, each dimension of interface regions 7 where the protective agent 6 does not exist is set to such a size that a plurality of conductive powders 4 constituting the via 3 can abutted on the wiring layer 2. Therefore, the plurality of conductive powders 4 and the wiring layer 2 are abutted each other in each interface region 7 where the protective agent 6 does not exist to electrically connect, thereby stabilizing the connection resistance for a prolonged period of time.