Heat radiator and power module

摘要

A heat radiator (20) includes an insulating substrate (3) whose first side serves as a heat-generating-element-mounting side, and a heat sink (5) fixed to a second side of the insulating substrate. Two stress relaxation members (4) formed of a high-thermal-conduction material are disposed between the insulating substrate and the heat sink and include each a plate-like body (10) and a plurality of projections (11) formed on one side of the plate-like body. A side of the plate-like body of one stress relaxation member on which the projections are not formed is metal-bonded to the insulating substrate, whereas a side of the plate-like body of the other stress relaxation member on which the projections are not formed is metal-bonded to the heat sink. The projections of one stress relaxation member are positioned in respective gaps between the projections of the other stress relaxation member, and the end faces of the projections of one stress relaxation member being metal-bonded to the plate-like body of the other stress relaxation member, and vice versa.