Semiconductor device with wire including a surface metal layer covering a core metal

Abstract

A semiconductor device includes first and second semiconductor elements, and first and second circuits at different potentials. The second semiconductor element, electrically connected to the first semiconductor element, relays mutual signals between the first and the second circuits, while insulating them. The semiconductor device further includes a first terminal lead electrically connected to the first semiconductor element, a first wire connected to the first and the second semiconductor elements, and a second wire connected to the first semiconductor element and the first terminal lead. The first wire contains a first metal. The second wire includes a first core containing a second metal, and a first surface layer containing a third metal and covering the first core. The second metal has a smaller atomic number than that of the first metal. The third metal has a greater bonding strength with respect to the first terminal lead than the second metal.