| 摘要 |
PURPOSE:To form a fine circuit while keeping wiring density, by laminating a three-layered metal foil composed of copper/nickel/copper in an united body, on at least the single surface of a board. CONSTITUTION:A three-layered metal foil composed of copper/nickel/copper is laminated on at least the single surface of an insulating board, and other metal layers except the copper layer on the insulating board side of the three- layered metal foil are eliminated. A hole turning to a blind through hole is formed, its inner wall is metallized, and etching resist is formed in the portion necessary to the circuit of the copper foil on the single surface and the part of a hole turning to the blind through hole. After that, the part exposed from the etching resist is etched and eliminated. The surfaces which are not worked for a circuit are set inside, and two similarly worked boards are made to face each other, and an inner layer circuit board is sandwitched by the boards. Further a prepreg for insulation is sandwitched by the board and the inner layer circuit board, and they are laminated into an unified body by heating and compression bonding. A hole turning to a through hole penetrating the whole is formed, and its inner wall is metallized. |
