| 摘要 |
<p>PURPOSE:To prevent a decrease in reliability of a circuit, by reducing the number of through holes in a wiring board. CONSTITUTION:On a face of a circuit 2 in a printed wiring board 1, a metallic foil 5 having a through hole 3 is put on a prepreg 4 having a through hole 3 so that both the through holes 3 are aligned with each other. In a thermo- compression step, a metallic foil 5 and the printed wiring board 1 are laminated with the prepreg 4 in between. With the use of both the through holes 3, a viahole 6 that is bored incompletely with a bottom face at the face of the circuit 2 in the printed wiring board 1 is formed. Then, the inside face in the viahole 6 is covered with through-hole plating 7. The metallic foil 5 is etched in a printing step to form a circuit 8. This circuit 8 is connected to the circuit 2 through the incompletely bored viahole 6 in the printed wiring board 1.</p> |
