Method of producing boards for printed wiring

A method of producing a metal-clad board for printed wiring comprising disposing a foil of the metal in a plate-shape cavity of a mold so that the metal foil is in contact with at least one internal side of the cavity, disposing at least one ceramic plate within the cavity and then injecting a molding material comprising an epoxy resin, a hardening agent and a powdery inorganic filler into the cavity and curing the epoxy resin;

• the molding material containing 50 to 90% by volume of the powdery inorganic filler based on the total of the molding material, and the powdery inorganic filler being selected from the group consisting of a silica powder, a cordierite powder, an alumina powder, an aluminum nitride powder, a silicon nitride powder, a boron nitride powder, a silicon carbide powder, a boron carbide powder, a beryllia powder, a titanium dioxide powder, a barium titanate powder, a calcium titanate powder, a strontium titanate powder, a lead titanate powder, a barium zirconate powder, a calcium zirconate powder, a barium stannate powder, a calcium stannate powder, a burned powder of a material of a ceramic capacitor, the burned powder having a relative dielectric constant of at least 300, and a mixture thereof;
• said metal foil providing an outer metal layer of the metal-clad board and the at least one ceramic plate being disposed in the cavity so that at least a portion of the at least one ceramic plate is embedded within the molding material to provide reduced thermal resistance and increased heat release of the metal-clad board.