Aging investigation of the latest standard dual power modules using improved interconnect technologies by power cycling test

Abstract

The latest standard “New Dual” power module has been developed for both silicon and silicon-carbide devices to meet the increasing demands in high reliability and high temperature power electronic applications. Due to the new package is just starting to release on the market, the reliability performance has not been fully studied. This paper investigates the power cycling capabilities of a 1.7 kV/1.8 kA IGBT power module based on the new package. Both the electrical and thermal performances have been studied before and after the power cycling. Neither the chips nor bond wires have noticeable degradation after 1.2 million cycles with ΔTj = 100 K and Tjmax = 150 °C. Nevertheless, the end-of-life criterion of an increased conduction voltage (Vce) in the test environment has been reached at about 600 k cycles. The further scanning acoustic microscopy test unveils that the fatigue site shifts from the conventional near-to-die interconnect (e.g., bond wire lift-offs) to the direct bond copper (DBC) substrate and baseplate layers. Considering the new package has more than ten times cycle life than the traditional power module, it expects the thermo-mechanical fatigue is not the life-limiting mechanism with further improved interconnect technologies. Meanwhile, as the previous bottlenecks (e.g., bond wires) are addressed, some new fatigue mechanisms, e.g., delamination of the DBC, become visible in this new package.