Patent ID: 7197820

Claim:
A circuit board manufacturing method, comprising the steps of: pressurizing and adhering uneven layers of first metal films to opposite sides of an insulating substrate, the insulating substrate having a through hole filled with conductive material comprising metal particles and resin, each of said uneven layers having a thickness exceeding 5 μm on a surface of a respective one of the first metal films; thinning the first metal films; forming second metal films, respectively, on the first metal films on opposite sides of the insulating substrate in a pattern for covering at least the through hole; removing a part of the first metal film, the part having no second metal film; contacting one uneven layer with said insulating substrate on one side thereof and another uneven layer with said insulating substrate on the opposite side thereof; and covering, by the uneven layers, at least the conductive material on each side of the insulating substrate.