| 摘要 |
PURPOSE:To enable holes to be improved in position accuracy and miniaturized so as to make a wiring board high in wiring density by a method wherein a blind viahole is bored in a multilayer printed wiring board with laser rays when the multilayer printed wiring board provided with a blind hole is formed. CONSTITUTION:A through-hole 3 is bored in a base material 1 on which a copper foil 2 is pasted, the copper foil 2 is etched to form a circuit 4a, and an insulator layer 5 of epoxy insulating resin is formed on the whole surface through a screen printing method excluding the through-hole 3. Then, an adhesive layer 6 formed of additive adhesive agent is applied on the layer 5 through a screen printing method and hardened, the layer 6 is treated with a roughening liquid mainly composed of CrO3 100g/l and H2SO4 300ml/l to turn into a roughened face 7, and a blind hole 8 is provided to a part where a blind viahole is formed by the irradiation with laser rays. Then, a resist layer 10 is provided to the whole surface through the intermediary of a catalyst 9, a copper plating layer 11 is formed on a part other than the layer 10 through a thick electroless plating method, and a viahole 12, a through-hole 14, and a prescribed circuit 4b are provided. |
