| 摘要 |
PURPOSE:To enable to conduct a through hole connection completely by a method wherein the plating on the through hole is performed using an electroless plating method. CONSTITUTION:A through hole 7 is perforated on a ceramic insulated board 6. Then, an activated layer 8 is adhered to the whole surface of the board 6 including the hole 7. Subsequently, glaze type conductive paste is coated on both front and back sides of the board 6 and glaze type resistive paste is coated at least on one side of the board, and thick film circuit conductive layers 9 and 9' and a thick film resistive layer 10 are formed by performing a high temperature sintering. Then, insulative resist layers 11 and 11' are formed on both front and back sides of the board 6 in such a manner that the hole 7 and a part of the layers 9 and 9' located on the circumferential part of the hole 7 will be exposed. Then, sais board 6 is dipped into an electroless plating solution, and a metal layer 12 is deposited on the inner wall surface of the hole 7 and the surfaces 9 and 9' exposed on the circumferential part of the hole 7. As a result, the layers 9 and 9' formed on both front and back sides of the board can be electrically connected completely through the hole 7. |
