Lifetime of power electronics interconnections in accelerated test conditions: High temperature storage and thermal cycling

We investigate the effect of three testing conditions (thermal shock, Rapid Temperature Change - RTC - and high temperature storage) on the interconnects of a power electronic module. In particular, the mechanical strength of thick aluminium wirebonds is investigated and shows that while it is not affected by storage at 230 °C, it is much more sensitive to thermal cycling. Shock tests are found to be especially severe, despite having a smaller temperature swing than RTC. Regarding the die attach, no noticeable reduction in mechanical strength is found, regardless of the ageing conditions, and despite clear micro-structural evolutions.