In a semiconductor module where a metal sheet, an insulating layer and a circuit element are stacked in a manner that the insulating layer is penetrated with a bump structure, the connection reliability of the bump structure and the circuit element is enhanced. A semiconductor wafer is prepared where a semiconductor substrate having electrodes and protective film on the surface are arranged in a matrix shape. On the surface of the semiconductor substrate, an insulating layer is held between the substrate and a copper sheet, integrally formed with bumps, having grooves in the vicinity of the bumps. The semiconductor substrate, the insulating layer and the copper sheet are press-bonded by a press machine into a single block. The bump penetrates the insulating layer, and the bump and the electrode are electrically connected together. An extra part of the insulating layer pushed out by the bump flows into the groove.