Fujitsu Corporation

Zhiyi Song

Kiyokazu Moriizumi

Norikazu Ozaki

Manabu Watanabe

Shunichi Kikuchi

Kazuaki Satoh

Misao Umematsu

Takami Sasahara

The method comprises forming a plurality of wiring pattern layers on the front surface of a substrate. In the process of forming the wiring pattern layers, an insulator protection film keeps covering over the wiring pattern on the back surface of the substrate. When the formation of the wiring pattern layers has been completed on the front surface of the substrate, a penetrating hole is bored in the cured or hardened insulator protection film. The penetrating hole may be utilized as a conductive via or a conductive through hole. A wiring pattern layer is then formed over the hardened insulator protection film on the back surface of the substrate. It is possible to omit an additional process for removing the insulator protection film. The method contributes to further facilitation of production process and further reduction in production cost.

Method of producing double-sided circuit board

A dummy pad is formed through a polyimide insulating layer so as to be provided opposite to a via connecting pad formed on the surface of a ceramic substrate. A defect occurring in the via connecting pad is filled with a protrusion when the dummy pad is formed. Accordingly, the influence of the defect upon a layer above the dummy pad is prevented. Further, in a method for manufacturing a thin film wiring board obtained by forming a thin film layer on a base substrate having a via that allows interlayer electric conduction, a void defect existing in the via is filled with a conductive material having corrosion resistance against an etchant, and then the thin film layer is formed on the base substrate.

Thin film wiring board and method for manufacturing the same, base substrate and method for manufacturing the same

Growing community of inventors

Kawasaki, Japan

Zhiyi Song