| 摘要 |
PURPOSE:To manufacture a circuit board in which wiring layout can be enhanced in density by electrolessly plating the wall of a hole and a wiring pattern. CONSTITUTION:A copper foil-clad laminated board containing an inner layer circuit is manufactured, and then a through hole 1 is opened by drilling. After insulation resin adhering to an end face of the hole of an inner layer wiring is dipped in alkaline solution containing permanganic acid, plating catalyst 2 is applied to the wall of the hole by using mixture plating catalyst containing palladium chloride and tin chloride. Then, plating resist 3 is formed on a part except a wiring pattern. In this case, the diameter of a land is larger than that of the drilled hole 1. Then, it is dipped in electroless nickel plating solution to form a plating 4. Thereafter, the resist 3 is removed, it is brought into contact with alkali etchant, and a copper foil 5 of a part not covered with electroless Ni is removed. Subsequently, solder resist 6 is printed. Eventually, electroless palladium plating 7 is executed to manufacture a multilayer circuit board. |
