Epoxy molding compound effect on fan-out wafer level package strength during post-mold thermal process

Fan-out wafer level packaging technology becomes more and more popular and attractive of its flexibility for integration of diverse devices in a tiny form factor. The small and thin fan-out wafer level package has low package strength and often faces crack issues. In the previous study, the fan-out wafer level package strength increased significantly when the wafers were lithographed passivation layers. The extreme thin passivation layers should not impact the package strength seriously. Therefore, the only explanation was any package material strength changed during the lithographing process. In this study, the thermal properties of epoxy molding compound were evaluated to understand the effect of epoxy molding compound on the package strength and reliability. Both Vickers hardness test and three-point bending test were used to evaluate the changing of epoxy molding compound strength. The results showed that the post-mold curing process and any post-mold thermal process had a significant effect on the epoxy molding compound strength.