PURPOSE: To prevent the deviation in position of a semiconductor device at the time of wire bonding by using such material which has an insulating sheet (insulating layer) in the middle and has two out of three layers, a metal layer, a non-conductive layer and a conductive layer, on an upper and a lower face of the insulating sheet.

CONSTITUTION: On a lead frame 1, a power semiconductor device 2 is mounted through solder and a controlling device (semiconductor device) 3 is mounted through insulating material 4. The insulating material 4 is three-layer structured and has an insulating layer in the middle. The insulating material 4 has an insulating layer 41 and an upper face layer 42 formed on the upper face of the insulating layer 41 and a lower face layer 43 formed on the lower face of the insulating layer 41. For the upper face layer 42 and the lower face layer 43, two out of three layers, a metal layer, a non-conductive layer and a conductive layer, are used. Therefore, at least either of the upper face layer and the lower face layer is the metal layer or the conductive layer. The conductive layer is formed by mixing conductive particles into the layer and the layer itself is thermoplastic resin or thermosetting resin.