Modelling the Lifetime of Heavy Wire-bonds in Power Devices – Concepts, Limitations and Challenges

Aluminum based wire-bonds are still representing the most important technology for the chip top side connection in power devices. At the same time, they often limit the reliability and lifetime of the overall power device or module. Hence, knowledge of the wire-bond reliability can be key for predicting and modelling the lifetime of the whole electronics assembly.In this paper, a short overview of load and design based lifetime models for power devices and modules together with their limitations will be given. Based on this, the requirements as well as the necessary process steps for developing a more generic lifetime model for wire-bond degradation using stress and damage parameters are discussed. This includes the development of global-local finite element models as well experimental measurements and test for material characterization, model calibration and validation. Finally, first results of a parametric finite element study evaluating the wire-bond lifetime depending on different geometry parameters and material combinations will be provided.