SUBSTRATE FOR POWER MODULE, SUBSTRATE FOR POWER MODULE WITH HEAT SINK, AND POWER MODULE WITH HEAT SINK

摘要

PROBLEM TO BE SOLVED: To provide a substrate for a power module which inhibits cracks from occurring in solder for joining a metal layer to a heat sink under a hot/cold cycle load and thereby prevents the deterioration of the joint reliability, the increase of heat resistance, and cracks in a ceramic substrate, and to provide the substrate for the power module with the heat sink and the power module with the heat sink.SOLUTION: A substrate for a power module includes: a circuit layer 12 formed on one surface of a ceramic substrate 11; and a metal layer 13 formed on the other surface of the ceramic substrate 11. The metal layer 13 includes: a first aluminum layer 13A joined to the other surface of the ceramic substrate 11; and a first copper layer 13B which is joined to the first aluminum layer 13A by solid phase diffusion bonding.