PRODUCTION OF MULTILAYER WIRING BOARD

摘要

PURPOSE:To eliminate open circuit or insufficient electrical connection due to level difference by a constitution wherein the upper end face of a pillar participating in the electrical connection between wiring pattern layers is kept in flush with the surface of interlayer insulation layer. CONSTITUTION:A dielectric film 2 is applied on the surface of a conductive supporting board 1 and a material layer 3 having high laser sensitivity is applied uniformly thereon. Holes 4 penetrating through the material layer 3 to reach the surface of the supporting board 1 are then made selectively at predetermined positions through irradiation of laser beam. The material layer 3 is then irradiated with laser beam and required patterning is performed on a part including the periphery of the through holes 4. Subsequently, electric copper plating is carried out using the supporting board 1 as a cathode thus growing copper plating layers 6a, 6b in the through hole 4 and on the surface of the patterning 5. This method eliminates level difference with respect to the dielectric layer through growth of plating on the surface of wiring pattern underlying the peripheral part thus realizing a highly reliable interlayer connection.