Cure Shrinkage Characterization and Warpage Simulation Optimization of Epoxy Molding Compound for 5G Application

With the development of electronic packaging technology in 5G era, System-in-Package (SiP) module is developing into smaller size and higher integration to realize the multi-functional applications, and the reliability of SiP module, especially the interfacial delamination has become one of the most concerned issues. To predict interfacial delamination precisely through modeling and simulation methodologies, accurate warpage of SiP module should be calculated accordingly since warpage deformation is one of the main reasons of interface delamination. For plastic packaged devices, like most SiP modules, coefficient of thermal expansion (CTE) mismatch between epoxy molding compound (EMC) and its adjacent materials will lead to warpage during the process of transfer molding and post-mold cure of EMC. In addition to this, another important reason of warpage is the chemical shrinkage of EMC during curing process. In this work, a method of characterizing cure shrinkage of EMC was proposed by using bi-material test method. The cure shrinkage rate of EMC was calculated combining the simulation methods and the warpage test results, which was applied in optimizing the SiP module warpage simulation during reflow process. Furthermore, the effect of viscoelasticity of EMC on SiP module warpage was also investigated in this work.