Static and dynamic finite element modelling of thermal fatigue effects in insulated gate bipolar transistor modules

The aim of this paper is to demonstrate the use of finite element technique s for modelling thermal fatigue effects in solder layers of insulated gate bipolar transistor (IGBT)- modules used in traction applications. The three -dimensional models presented predict how progressive solder fatigue, affec ts the static and dynamic thermal performance of such devices. Specifically, in this paper, the analysis of an 800 A-1800 V IGBT module is performed. In the first part, the static analysis is realised. The paramet ers assessed are thermal resistance, maximum junction temperature and heat flux distribution through the different layers comprising the module constr uction. In the second part of the paper, transient analyses are performed i n order to study the dynamic thermal behaviour of the module. The construct ed thermal impedance curves allow for calculation of the device temperature variations with time. Stress parameters, such as temperature excursion and maximal temperature at chip and solder interfaces, are determined. Calibra tion of all simulation models is achieved by comparison with alternative th eoretical calculations and manufacturers' measured values provided in the d ata sheet book. (C) 2000 Elsevier Science Ltd. All rights reserved.