Package Warpage Modeling by Considering Shrinkage Behavior of EMC and Substrate

This paper demonstrates a novel finite element modeling (FEM) approach by considering shrinkage behavior in Epoxy Molding Compound (EMC) and substrate material during assembly reflow process. Based on shrinkage mechanism on EMC and substrate, material characterization activities using bi-material sample and Digital Image Correlation (DIC) are performed to examine relative shrinkage amount in EMC and substrate interposer among different suppliers and material types. With sequential application of EMC and substrate shrinkage in finite element modeling, an optimal simulation setting is established to capture actual package warpage behavior of memory ball grid array packages in reflow process. With enhanced model accuracy, it greatly accelerates package structure and bill of material selection in early design stage.