Practical aspects for 3D simulation of underfill encapsulation

In this study, a general-purpose, 3D simulationy technique is proposed to track the propagation of the underfill in microchips. The capillary underfill flow, which is mainly driven by the surface-tension force based on the contact angle between bumps and substrate, of dispensing process is investigated by numerical analysis. Specifically, two cases are used to test the capability of simulation. The first case simulates the underfill flow in PDMS microchannel with infinite inlet melt. The melt-front distribution shows good agreement with experimental observations. The other case demonstrates the modeling of multi-pass dispensing underfill flow behavior. The results not only exhibit the rationality of flow behavior, but also display the curve of filled volume growing during the multi-pass dispensing process. With rational prediction of flow pattern and capability of multi-pass dispensing process followed the mass conservation, it is convinced that the simulation technique provides a promising simulation solution for the microchip encapsulation process.