Effect of Joule heating on the reliability of solder joints under power cycling conditions

In the field, electronic devices are often experiencing switching cycles. With the trend of miniaturization and electrification, automotive electronic packages are facing increasingly critical reliability issues regarding current stressing and the accompanying Joule heating. In this work, the load capability of two surface-mounted shunt components subjected to cyclic current pulses is investigated. Asymmetric self-heating due to the Peltier effect is observed with infrared thermography in one of the shunt components, which leads to polarity in the micro structural evolution influencing the failure mode in the solder joint. Finite element method (FEM) is utilized to simulate the coupled electrical, thermal and mechanical fields in the assembly and to assess the response of the solder joints exposed to power cycling. Lifetime data are collected and statistically analysed based on the Weibull distribution.