| 摘要 |
PROBLEM TO BE SOLVED: To provide manufacture of a multilayer printed wiring board which may be formed with high productivity by a process simplifying a via-hole. SOLUTION: On the surface of a circuit board 2 having a wiring pattern 1 formed thereon, a metal foil 4 is stacked via an insulating resin layer 3. A protective film 5 durable to an etching solution is bonded onto the surface of the metal foil 4. By irradiating a portion of the protective film 5 where a via-hole 6 is to be formed with a laser beam, a base hole 7 extending to the metal foil 4 is formed in the protective film 5. Then, by causing the etching solution to act on the metal foil 4 through the base hole 7, the metal foil 4 at the portion of the base hole 7 is removed to provide an aperture portion 8 in the metal foil 4. Next, by making a hole by irradiating the insulating resin layer 3 with a laser beam through the base hole 7 in the protective film 5 and the aperture portion 8 in the metal foil 4, the via-hole 6 is provided. Subsequently, a conductive material 9 is formed in the via-hole 6 to electrically connect the wiring pattern 1 on the circuit board 2 with the metal foil 4. |
