Power Transistor Chips on Heat Sink: Evaluation of Different Mounting Techniques

Assembly techniques for power semiconductor devices destined for automotive applications are examined. Attention has been paid to materials or their combinations showing an acceptable compromise between good thermal conductivity and low cost. Extensive work has been carried out on type and/or thickness of same to minimise the strains dependent on different TCEs. Measurements and tests on thermal resistance have been performed. Rth measurements, together with thermal fatigue cycle and cycled life test, have confirmed themselves as a very suitable way to study and optimise the assembly technique for power devices.