Abstract: A zinc based solder material 55 of the present invention is prepared by providing on the surface of a zinc based material 50, from which an oxide film 501 has been removed or at which an oxide film 501 does not exist, with a coating layer 51 containing primarily a metal whose oxide is more easily reducible than the oxide film 501. In a joined body and a power semiconductor module of the present invention, the zinc based solder material 55 is used in the joining portion, and after joining, the coating layer 51 does not exist.

Abstract: An ebullient cooling device having a simple structure and capable of limiting the bubbles to an appropriate volume. The ebullient cooling device for cooling a heat generating element is provided with a plurality of vertically arranged cooling channels comprising a lower channel (2), a middle channel (3) and un upper channel (4). Each cooling channel has cooling fins (12) for guiding a refrigerant to flow in a vertical direction, and a vapor discharge path (16) formed at the side of the cooling fins (12) that is opposite the side in contact with the heat generating element. Furthermore, flow path partition/vapor discharge guiding plates (18) are provided between the cooling channels so that the bubbles that have been generated are guided to the vapor discharge path (16) and prevented from moving into the subsequent cooling channel.

Abstract: A zinc based solder material 55 of the present invention is prepared by providing on the surface of a zinc based material 50, from which an oxide film 501 has been removed or at which an oxide film 501 does not exist, with a coating layer 51 containing primarily a metal whose oxide is more easily reducible than the oxide film 501. In a joined body and a power semiconductor module of the present invention, the zinc based solder material 55 is used in the joining portion, and after joining, the coating layer 51 does not exist.

Abstract: Provided is a power semiconductor module in which two components are bonded by a Bi based solder material. A Cu layer is provided on the surfaces thereof to be bonded by the Bi based solder material on the two-component. Two components, i.e., the components to be bonded, are a combination of a semiconductor element and an insulating part, or a combination of an insulating part and a radiator plate. The insulating part is composed of a Cu/SiNx/Cu laminated body.