Board Level Reliability of Gull-wing, Micro-leaded and Lead-less Packaged MOSFETs in Automotive Environments

This paper explains the board level reliability of popular surface mounted power MOSFET packages which are found in automotive environments and applications. Even when AEC-Q101 standards are met, the package footprint geometry of a MOSFET inevitably has an influence on board level performance. Thermomechanical simulations were performed alongside experimental testing on micro-leaded 3x3mm² MOSFET packages, which resulted in good agreement between experimental and simulation data. A relative comparison was made through temperature cycling simulations of gull-wing, micro-leaded and lead-less packages between -55°C to 150°C as per AEC-Q101. This was done to evaluate the solder fatigue of 3x3mm² packages, which are widely used in automotive applications. The averaged accumulated creep strain per temperature cycle from simulations was then used in the double power law model derived from literature to predict MOSFET lifetime on a printed circuit board (PCB). From which, the findings of the investigation showed that gull-wing leaded MOSFETs were predicted to have higher board longevity, followed by micro-leaded and lead-less packages.