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

摘要

PROBLEM TO BE SOLVED: To provide a substrate for a power module with a heat sink, which can efficiently diffuse heat generated from an electronic component or the like and having high heat cycle reliability. SOLUTION: The substrate for the power module with the heat sink includes: the substrate 10 for the power module where a circuit layer 12 is formed on one surface of an insulating substrate 11 and a metal layer 13 is formed on the other surface; and the heat sink 4 bonded on the side of the metal layer 13. In this case, the buffer layer 30 comprising an aluminum base composite material for which aluminum or an aluminum alloy is filled in a carbonaceous member is provided between the metal layer 13 and the heat sink 4, wherein the thermal expansion coefficient K of the buffer layer 30 is in the relation of Kc