| 摘要 |
PURPOSE:To prevent insulator from deteriorating due to an electrolytic corrosion at the time of application of voltage between wiring conductors on and in an insulating board by interposing nickel of substance having less transfer of components due to an electric field between copper of wiring conductor and the board. CONSTITUTION:An inner layer circuit conductor 2 is formed of metal copper foil on an insulating board 1. A metal nickel layer 3 is formed by nickel plating on the conductor 2. However, an insulating layer 4 made of an insulating base material must be provided between inner layer circuit conductor layers and between it and a board surface circuit conductor layer 5. Then, a hole to become a through hole is opened. A metal nickel plate 7 is formed by nickel plating on the inner wall 6 of the hole. Thus, an insulation deterioration can be effectively prevented not only on the board but between the conductor and the inner wall of the hole. |
