MULTILAYER WIRING BOARD AND ITS MANUFACTURE

PURPOSE:To prevent the reaction of a wiring layer and an insulating layer without increasing manufacturing processes in a multilayered wiring board wherein the wiring interlayer insulating film is an organic polymer insulating film, and realize a multilayered wiring board of high reliability. CONSTITUTION:On a ceramic board 1, wiring conductor (copper) 3 whose surface is flat is formed by electrolytic plating, via a base conductor film 2. The wiring conductor 3 surface is covered with a reaction preventing film 4 by nonelectrolytic plating, and the film 4 surface is covered with an anti-oxidant film 8, which is desirably formed by, e.g. substitution plating of gold. Since the surface layer part of the reaction preventing film 4 as the base is dissolved and the left part is plated with gold, so that a special surface treatment for cleaning the surface is made unnecessary. Further a polyimide interlayer insulating film 6 is formed, holes for wiring connection are formed, and a base conductor film 7 is formed. The forming processes from the wiring conductor (copper) 3 to the base conductor film 7 are repeated by the number of time corresponding with the number of lamination layers of wiring.