| 摘要 |
PURPOSE:To remove pin holes, and to obtain excellent wire bonding property by compactly plating a copper foil layer or a copper plated layer formed on the surface of a board for a printed wiring with a metal, into which copper is difficult to permeate, through a suction flow method and compactly coating the metal extremely thinly with gold in high purity through the same method. CONSTITUTION:When a bonding pad is formed on the surface of a board 1 for a printed wiring, the surface is coated with a copper foil layer or a copper plated layer 2, and the copper foil layer or the copper plated layer 2 is formed to a predetermined shape. The exposed surfaces of the surface and side surface of the copper foil layer or the copper plated layer are coated with a layer 3 in nickel, etc., into which copper is difficult to permeate, and a gold layer 4 in high purity of not less than 99.9% purity is formed on the layer 3 while the thickness of the layer 4 is brought to 0.4mum or less. Both the layers 3, 4 are prepared through a suction method at that time, and a pad surface in which there is no pin hole is obtained even when the gold layer 4 is thinned. Accordingly, the secular deterioration of wire bonding is eliminated. |
