JPH05335701

PURPOSE:To improve heat dissipation while keeping strength and processability of a resin substrate by boring a required position of a non-heat dissipation predetermined part of a metallic base wiring substrate and by charging the bored part with resin material integrally. CONSTITUTION:A through-hole of a diameter of 10mm is shaped at a required position of a non-heat dissipation predetermined part of a 1.6mm-thick aluminum base copper clad lamination board. A paper-based phenol resin lamination board of a diameter of 10mm and a thickness of 1.6mm is fitted to the opening to acquire a composite wiring substrate. Otherwise, time opening part is charged with epoxy resin cast material whereto 300 parts by weight of silica to 100 parts by weight of curing material containing epoxy resin is added and heated at 160 deg.C for 30 minutes. Thereby, heat dissipation property can be improved while keeping strength and processability of a resin substrate.