Simulating underfill flow for microelectronics packaging

Underfill flow simulation is not yet sophisticated enough to understand the microdynamics. Although capillary action generally drives the filling phenomenon, it is the underlying principles that govern the underfill performance properties that are in need of understanding. For instance, flow speed, filler settling, filler striation and voiding are all properties that require a mechanistic understanding in order to improve the materials. Although binder and filler effects are expected from a combination of surface energy and particle dynamics drivers, the simple identification of the problem does not instruct how to control these effects. In order to address these issues two types of dynamic modeling have been initiated to understand formulation constituent effects: molecular modeling and discrete element modeling. It has been the goal of this modeling effort to construct a basic model of underfill flow which includes particle, binder (or carrier) and surface effects