Hitachi, Ltd.

Takayoshi Sowa

Hitoshi Yokono

Naoya Kanda

Tetsuya Yamazaki

Akio Fujiwara

Hiroaki Okudaira

Shoichi Iwanaga

A method for forming conductor layers of substrates for mounting LSIs and the like and a fabrication method of multilayer substrates are disclosed. These methods comprise steps of forming a metal underlayer having a shape similar to that of a conductor pattern on the substrate, forming an insulation layer over portions of the substrate which are not covered by the metal underlayer, and disposing a plating layer on the metal underlayer by carrying out electroless plating while using the insulation layer as the resist and thereby forming conductors. As compared with a conventional conductor layer forming method, the number of fabrication steps is reduced. And the elimination of the surface grinding step facilitates the fabrication.

Method for forming conductor layers and method for fabricating

The present invention relates to an element comprising a superconductive material or a wiring formation technique. In a thin film wiring board in which a superconductive material is used as a conductor, annealing should be conducted at a high temperature in an oxygen atmosphere after formation of a film in order to convert the conductor portion into a superconductive material, which makes it necessary to use an inorganic oxide as the insulating film. This brought about a problem that the etching of the second and subsequent insulation layers causes a damage to the wiring and insulation layer provided thereunder. In the present invention, an over-etching preventing layer is provided on a wiring layer provided under the second and subsequent insulation layers in order to solve the problem in question. The present invention brings about an effect of realizing the formation of a multi-layered wiring layer by making use of a superconductive material.

Process for preparing superconductive wiring board

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Fujisawa, Japan

Takayoshi Sowa