Adhesion strength between conductive paste and lands of printed wiring board, and manufacturing method thereof

摘要

Copper foil lands provided with a through-hole filled with a copper paste are provided with ring-formed hollow portions in the periphery of the through-hole where exfoliation between the copper paste and the copper foil lands normally occurs to obtain a copper-plated through-hole in both sides of a printed wiring board using a paper-phenol substrate, wherein adhesion strength between the copper foil lands and the copper paste is enhanced.