Thermo-mechanical structural analysis of a press-packed IGBT

In this study stresses and strains in a press-packed integrated gate bipolar transistor (IGBT) due to assembly and thermal cycling were determined by the Finite Element method. 2D and 3D models of the device were developed including an elastic-plastic material description and the contact simulation using the ABAQUS code. The assembly process was initially simulated and the factors affecting the contact pressure uniformity between contact disks and chip discussed. The thermal cycling associated to accelerated testing was then introduced to examine contact pressure variations and local stress/strain concentrations. Implications on possible damage initiation in the device due to thermo-mechanical fatigue and/or fretting were identified.