MULTILAYERED PRINTED WIRING BOARD AND ITS MANUFACTURE

摘要

A multilayered printed wiring board having a smooth surface, which can be improved in resolution, interlayer insulating property, or thermal shock resistance without lowering its peel strength even if its insulating resin layer is thin. In the printed wiring board in which the conductor circuits of upper and lower layers are electrically insulated from each other by means of the insulating resin layer, the insulating layer is constituted of a composite layer composed of a lower layer made of a heat-resistant resin which is hardly soluble in an acid or oxidizing agent and an upper layer made of a bonding agent for electroless plating composed of a heat-resistant resin and, as necessary, a recessed section formed between conductor circuits of the lower layer is filled with a resin to the level corresponding to the surfaces of the conductor circuits.