In-situ Cure Shrinkage Characterization of Epoxy Molding Compounds for Fan-Out Wafer-Level Packaging

Wafer warpage has remained as a big issue in the semiconductor industry due to the defects it may cause, such as delamination and cracks in the molded devices. In the FOWLP process, the wafer warpage becomes even more critical due to the stringent process requirements. Although quite a few models have been set up to predict the shrinkage and warpage, research on the correlation between the Epoxy Molding Compound (EMC) cure shrinkage and warpage is still very limited due to the lack of experimental data input on the chemical cure shrinkage. In this paper, the chemical cure shrinkage of five main stream EMCs used in FOWLP were investigated in-situ. Differential Scanning Calorimeter (DSC) was used to monitor the curing process, in order to find out a suitable heating profile for shrinkage test. Thermomechanical analyzer (TMA) equipped with a dilatometer accessory was used to investigate the real-time shrinkage of EMCs at an isothermal curing condition. The results show that the chemical cure shrinkage of the selected EMCs is between 0.4% and 4%.