Thermo-mechanical finite element analysis in press-packed IGBT design

The reliability of press-packed insulated gate bipolar transistors (IGBTs) depends on satisfactory contact conditions applied at assembly stage and maintained throughout the service life. The objective of this work is the simulation of stresses and strains in press-packed IGBTs due to assembly and thermal cycling. Single-chip as well as multi-chip devices were analyzed with 2D and 3D models including an elastic-plastic material description and the contact between components using the ABAQUS code. The assembly process was initially modeled and the factors affecting the contact pressure uniformity between contact disks and chip discussed. The thermal cycling associated with accelerated stress test was then introduced to examine contact pressure evolution as well as local stress/strain concentrations and stick/slip conditions. The device sensitivity to potential damage initiation due to thermo-mechanical fatigue and/or fretting is addressed. (C) 2000 Elsevier Science Ltd. All rights reserved.