A Method for Detecting the Start of Delamination at the Corners of Solder Joint in a 3D PCB Power Electronic Assembly of SiC MOSFETs

The article discusses a method for evaluating the delamination initiation at solder joint corners in a 3D power electronic assembly of SiC MOSFET transistors integrated into a PCB substrate to design a half bridge. This assembly leads to soldering two metallic materials and addresses the integration of small active chips with larger heat-sinks. This technological development is part of future robustness evaluation of the new assembly model for wide band Gap components. This assembly consists of metallic base-plate corresponding to the heat-sink soldered on the copper foil of a PCB substrate. Conventional methods fail to detect delamination initiation effectively due to the optimized commutation cell design. Finite element simulations are carried out to assess the sensitivity in comparison with another method. Then, prototypes with controlled delamination rate are developed to consolidate the results. The first conclusion demonstrates the interest of that electrical method which is more sensitive to detect the low delimitation rates comparing to thermal method generally used.