Design and Reliability Considerations for Top-Side Cooled Power Semiconductors in Automotive Power Electronics

Inhalt:
The drive for higher power density in automotive systems introduces significant thermal management challenges. Top-Side Cooled (TSC) MOSFETs offer advantages enhancing power density, but concerns remain regarding reliability and integration. TSC devices are exposed to greater thermomechanical stress during thermal cycling than bottom-side cooled (BSC) counterparts, due to coefficient of thermal expansion mismatches and limited Z-axis compliance. This paper presents a thermal and reliability assessment of various TSC thermal interface scenarios, including variations in attachment pressure and compound type and thickness. Reliability is evaluated through parametric shifts measured at specific intervals during active thermal cycling, providing new insights into the device behavior under more realistic operating conditions. To the best of our knowledge, this represents the first reliability assessment of TSC devices under active rather than passive thermal cycling. The aim of this paper is to give designers insights and confidence in the use and integration of TSC packages.