Impact of PCB-housing-interaction on QFN solder joint reliability

This work concerns the impact of mounting the PCB onto the housing with respect to the reliability of the solder joints of components assembled to this board. Due to the thermal expansion mismatch between the housing and PCB, additional stress is applied to the board and consequently also to the soldered components. This additional stress induced by the CTE mismatch between board and housing results in a reduction in lifetime of the solder joints. This reduction depends on the location of the board. In this work, the impact is experimentally tested for QFN components soldered to a test board which was on its turn also screwed to an aluminum plate. The test results are explained by FEM simulations.