Mechanical Analyses of Advanced Multi-Chip Embedded Wafer Level Packages

Abstract

ncreasing functionality accompanied with device miniaturization in microelectronics has led to increased market demand for packages with small form factor. Over the years, embedded wafer level packaging (EWLP) has become an attractive option since it allows a reduction in package size and height. In the EWLP approach, the singulated dies are embedded within the molding compound through the wafer level compression molding process. For this study, critical mechanical challenges such as die shift and thermal cycling performance of a multi-chip embedded wafer level package (MCEWLP) are addressed through numerical modeling. For improved accuracy in die shift predictions, both mechanical effects and fluidic effects need to be taken into account. Mechanical effects account for around 75% of the die shift while fluidic effect contributes to the remaining 25%. It is shown that reducing the die size and the inclusion of UBM as a buffer layer can effectively increase the fatigue life of the packages.