Simulation and Analysis for Capillarity Underfill Process in High Density FCBGA Packaging

The capillary underfill (CUF) process is an extensive application in electronic devices, and still remains an active research subject, especially in underfill material research. In this study, a dynamic 3D numerical simulation is established to visualize the CUF process in a flip-chip ball grid array (FCBGA) package. The material properties of curing kinetics and viscosity are characterized and molded in order to reflect the filling behaviors of the encapsulant through the simulation method. In addition, with the proper selection of the meshing method, melt front advancement with simulation time is consistent with the experimental results. Furthermore, the simulation method is used to study the effects of the contact angle and the dispensing process variable, which would provide an instructive solution for process optimization.