| 摘要 |
PROBLEM TO BE SOLVED: To provide a process for producing an inexpensive build-up printed wiring board with a head spreader in which high density wiring can be formed. SOLUTION: A first wiring layer is formed by electrolytic plating using a resist arranged on one side of a conductive substrate as a plating mask. Following to a series of circuit forming process comprising steps (a) for forming an insulating layer and a metal foil on the entire surface to cover the wiring part, (b) for forming the wiring part by photoetching the metal foil formed in layer, (c) for making a via hole connecting the wiring layers and then filling the via hole by carrying out electrolytic plating using the conductive substrate as a power supply layer, electrolytic plating is carried out in the region for forming an external connection terminal of a surface insulation layer covering the uppermost wiring layer using the conductive substrate as a power supply layer. An external connection terminal is then formed on the surface insulation layer and the conductive substrate used as the power supply layer is etched selectively. A heat spreader part is formed along with a frame part by the remaining part of the conductive substrate. COPYRIGHT: (C)2004,JPO |
