| 摘要 |
PURPOSE:To settle insufficiency of a strength in plating technique and to eliminate nonuniformity in a bonding strength by a method wherein an intermediate layer prepared by diffusing a diffusive material constituent in ceramic and sintering the ceramic to a board is provided between a conductive layer and the board. CONSTITUTION:A circuit board is constructed of a multilayer substrate 1 of ceramic, a conductive layer 2 and an intermediate layer 3 provided on the boundary between the conductive layer 2 and the ceramic substrate 1. The intermediate layer 3 is formed of a layer of a material being diffusive in the ceramic or a layer containing this diffusive material, and it is sintered to the ceramic by heat treatment for diffusing this diffusive material in the ceramic. Since a circuit strand of the conductive layer is sintered to the ceramic substrate, according to this method, a bonding strength is increased, nonuniformity in the bonding strength is reduced and thus reliability can be improved. Besides, a bare chip can be mounted directly, while a superprecision pattern can be formed by photolithography, and thus the degree of integration can be raised. |
