| 摘要 |
PURPOSE:To utilize through-hole parts provided in a printed interconnection board as connection parts by a method wherein copper balls are inserted into the through-holes so as to close them and solder bumps are formed on the copper ball parts. CONSTITUTION:Copper balls 13 are put on the necessary positions of a printed board 1 having through-holes 4 and copper foil patterns 2 and 3 and pushed into the holes 4 so as to be flush with the copper foil patterns. Then cream solder is applied by printing and solder bumps 9 are formed by reflow. Further, insulating adhesive resin 10 is applied by printing and dried and thermally cured. The two such printed boards are held between stainless steel plates and compressed and heated to form molten solder bump junctions 11 and insulating adhesive layers 12. Thus, a four-layer printed interconnection board can be obtained. |
