Thermo-mechanical design of fan-out wafer level package for power converter module

In this paper, thermo-mechanical simulations including wafer level warpage, thermal cycle and power cycle were conducted for the fan-out wafer level package (FOWLP) test vehicle of power converter module. From the simulation results, the wafer level warpage of 8 inch molded wafer can achieve the warpage target of lower than 1mm during the process flow from after molding, after back side grinding to after RDL fabrication with low CTE epoxy molding compound (EMC). The simulation results also demonstrated that the solder joints can pass 1000 thermal cycles with the loading of -65°C-150 °C. EMC with higher CTE can help to enhance the reliability of solder joints between the package\PCB. But the usage of the higher CTE EMC was limited by the wafer level warpage requirement. The power cycle simulation results demonstrated that the proposed FOWLP test vehicle for the power converter module can pass 10 K power cycles with junction temperature variation range of ΔT=100 °C.