Degradation behavior of 600 V-200 A IGBT modules under power cycling and high temperature environment conditions

One challenge for automotive hybrid traction application is the use of high power IGBT modules that can withstand high ambient temperatures, from 90 degrees C to 120 degrees C, for reliability purpose. The paper presents ageing tests of 600 V-200 A IGBT modules subjected to power cycling with 60 degrees C junction temperature swings at 90 degrees C ambient temperature. Failure modes are described and obtained results on the module characteristics are detailed. Especially, physical degradations are described not only at the package level, like solder attach delaminations, but also at the chip level, with a shift on electrical characteristics such as threshold voltage. Finally, numerical investigations are performed in order to assess the thermal and thermo-mechanical constraints on silicon dies during power cycling and also to estimate the effect of ambient temperature on the mechanical stresses. (C) 2007 Elsevier Ltd. All rights reserved.