Double-sided substrate, semiconductor device and method for the same

摘要

A double-sided substrate includes a ceramic substrate, a first metal layer formed on one surface of the ceramic substrate and having a plurality of subsidiary metal layers which are laminated on the surface of the ceramic substrate and whose purities differ from each other and a second metal layer formed on the other surface of the ceramic substrate, wherein the closer to the ceramic substrate any subsidiary metal layer is located, the lower purity the subsidiary metal layer has. Additionally, a semiconductor incudes the above double-sided substrate, a power element and a heat sink.