Uncertainty Assessment Framework for IGBT Lifetime Models. A Case Study of Solder-Free Modules

Insulated gate bipolar transistors (IGBTs) are ubiquitous semiconductor devices used in diverse electronic power applications. The reliability and lifetime assessment of IGBTs is intricate and influenced by different ageing processes. One of the main ageing mechanisms is the bond wire lift-off failure mode. The model used to describe this failure mode and estimate the IGBT lifetime is influenced by different variables and factors, which are stochastic, and tend to be specifically adjusted for different IGBT modules and applications. However, unless these variables are not assessed with respect to potential sources of uncertainty, the IGBT lifetime estimate leads to a single-value deterministic estimate, which, frequently, results inaccurate. In this context, assessing the influence of the variability of these variables on the lifetime model is a crucial activity for an uncertainty-aware IGBT lifetime estimate and adoption of appropriate sensing technology. Accordingly, this paper presents a methodology to evaluate the impact of the uncertainty of IGBT lifetime parameters on the lifetime estimate. The approach is first validated on three different experimental IGBT operation profiles, demonstrating the impact of variations of certain variables on the damage estimation. The approach has been tested here for a single lifetime model, but it is generally applicable to other IGBT lifetime models.