| 摘要 |
PURPOSE:To enhance a adhesion between a through hole pad part and copper paste in a copper paste through hole, and also set a resistance value of the copper paste through hole to be a stable low value. CONSTITUTION:In a printed wiring board that a front surface wiring circuit pattern 7 formed on a surface of a substrate is connected with a back surface wiring circuit pattern 8 formed on a back surface thereof via a copper paste hole 13 formed by filling a penetrating hole 4 for a through hole formed in the substrate with copper paste 12 to be stiffened, the surface of through hole pad parts 5, 6 of each wiring circuit pattern has been beforehand treated with a solution containing hydrochloric acid before the copper paste 12 is filled in the penetrating hole 4 for a through hole. |
