Dendrite Formation in Power Electronics Packages during HV-H3TRB Testing due to Flux Residue

In previous HV-H3TRB testing severe dendrite growth was observed on power MOSFETs. In this work we investigated the influence of solder flux residue on the growth of dendrites in power modules. HV-H3TRB testing of commercial power modules yields visible damage to the devices, while electrical performance remains acceptable. Intentional contamination with solder flux did not affect the modules. Further testing with test silver and copper test structures revealed that flux residue, but also other contaminants are a cause for dendrite formation in the presence of silver metal and can be eliminated by appropriate cleaning steps.