Patent ID: 8193634

Claim:
A mounted planar semiconductor device, comprising: a heat sink having a flat surface, a submount having two opposing first and second flat surfaces, and a planar semiconductor device having a flat mounting surface, wherein the flat surface of the heat sink is soldered to the first flat surface of the submount using a first solder film, and the second flat surface of the submount is soldered to the flat mounting surface of the planar semiconductor device using a second solder film, so as to form a stack; wherein the planar semiconductor device, the submount, and the heat sink have first, second, and third coefficients of thermal expansion CTE 1 , CTE 2 , and CTE 3 , respectively, wherein said coefficients of thermal expansion are measured in a direction parallel to said flat surfaces, and wherein CTE 3 >CTE 1 >CTE 2 or CTE 3 <CTE 1 <CTE 2 .