Development of Solder Deterioration Diagnosis System of a Power Module via the Acoustic Emission Monitoring (AEM) Technique

In this work, we applied a acoustic emission monitoring (AEM) technique to inspect solder deterioration in a clip-bonding SiC MOSFET power module during power cycling test (PCT). Solder deterioration was confirmed by SAT image and successfully monitored via the AEM technique. By analyzing the AE signals, it is found that cumulative AE signals are meaningful in identifying the deterioration of the solder layer in the power module. Crack initiation, crack propagation and severe damage can be differentiated via the AE signals. Meanwhile, the relationship between thermal resistance of the power module and cumulative AE counts was investigated. The variation of thermal resistance revealed an alike tendency to the cumulative AE counts curve, which might provide a quantitative assessment approach in AEM. These results suggest that the AEM technique can be a promising approach for evaluating the health condition of the solder deterioration in the PCT.