Low-temperature fired ceramic circuit substrate with improved Ag- Au connection reliability

摘要

A low-temperature fired ceramic circuit substrate includes a plurality of laminated insulating layers each formed of a low- temperature fired ceramic fired at a temperature ranging between 800 and 1,000 C., an inside layer wiring conductor formed of a conductive material of Ag system which is mainly composed of Ag, the inside layer wiring conductor being disposed in the inside insulating layer, a surface layer wiring conductor formed of a conductive material of Au system which is mainly composed of Au, the surface layer wiring conductor being disposed on the surface insulating layer, and an intermediate metal layer formed of a thick film paste of a conductive material of Au/Ag system which is mainly composed of Au/Ag, the intermediate metal layer being interposed between the inside layer wiring conductor and the surface layer wiring conductor.