| 摘要 |
PURPOSE:To obtain a printed-wiring board by piling an insulation layer and a copper foil without including a catalyst at both sides of a laminated board including a catalyst, by providing opening, and then performing electroless copper plating after forming an external layer circuit. CONSTITUTION:Insulation layers 2 without including a catalyst are piled up at both sides of a laminated board 3 including a catalyst and a copper foil 1 is piled up at the outside. This copper-clad laminate is drilled and an electroless copper plating is performed after forming an external layer circuit. The thickness of an insulation layer 2 without including catalyst should be equal to or less than 0.8times larger than the plating thickness. One part of insulation layer without including catalyst is exposed to the penetration hole. However, if the thickness of the insulation layer 2 is two times or less than the plating thickness, plating film grows from the copper foil 1 and the insulation layer 3 including catalyst and coats this area. Especially, when the thickness of the insulation layer 2 is not more than 0.8times larger than the plating thickness, the minimum plating thickness becomes 0.9times or more larger than the plating thickness, which is extremely appropriate. This configuration allows plating are per unit area surface of printed wiring to be reduced. |
