A power module is fabricated, employing a clad metal that is formed by pressure-laminating aluminum and copper, in such a manner that the aluminum layer of the clad metal is bonded such as by ultrasonic bonding to the surface electrode of the power semiconductor chip and a wire is bonded to the copper layer thereof to establish electrical circuit. The clad metal is thermally treated in advance at a temperature higher than the operating temperature of the power semiconductor chip to sufficiently form intermetallic compounds at the interface between the aluminum layer and the copper layer for the intermetallic compounds so as not to grow in thickness after the bonding processes.

A method for applying a bonding layer that is comprised of a basic layer and a protective layer on a substrate with the following method steps: application of an oxidizable basic material as a basic layer on a bonding side of the substrate, at least partial covering of the basic layer with a protective material that is at least partially dissolvable in the basic material as a protective layer. In addition, the invention relates to a corresponding substrate.

A method for applying a bonding layer that is comprised of a basic layer and a protective layer on a substrate with the following method steps: application of an oxidizable basic material as a basic layer on a bonding side of the substrate, at least partial covering of the basic layer with a protective material that is at least partially dissolvable in the basic material as a protective layer. In addition, the invention relates to a corresponding substrate.

A method for applying a bonding layer that is comprised of a basic layer and a protective layer on a substrate with the following method steps: application of an oxidizable basic material as a basic layer on a bonding side of the substrate, at least partial covering of the basic layer with a protective material that is at least partially dissolvable in the basic material as a protective layer. In addition, the invention relates to a corresponding substrate.

A method for applying a bonding layer that is comprised of a basic layer and a protective layer on a substrate with the following method steps: application of an oxidizable basic material as a basic layer on a bonding side of the substrate, at least partial covering of the basic layer with a protective material that is at least partially dissolvable in the basic material as a protective layer. In addition, the invention relates to a corresponding substrate.

A semiconductor device is provided, including a die constituting the top layer of the semiconductor device, preferably made of silicone; a lead frame constituting the bottom layer of the semiconductor device, having high electrical conductivity in the range between 6.310.sup.7 Siemens to 110.sup.6 Siemens more preferably 110.sup.7 Siemens (electrical conductivity is normally measured in Siemens per meter S/m, range of conductivity for Cu alloy lead frames are between 5 to 610.sup.7 S/m) for example made of L/F C19210 material; a first layer formed from a metallic foam located between the lead frame and the die, with a thickness preferably in the range of 500 nm to 5000 nm more preferably 2000 nm, and with a porosity in range of 30% and 90% preferably 60% and a second layer located between the die and the lead frame being only partially in surface contact with the first layer.