Underfill of flip chip on laminates: Simulation and validation

The how characteristics of a number of underfills were evaluated with quart z dies of different patterns and pitches bonded on different substrate surf aces, Perimeter, mixed array, and full array patterns were tested, Observat ions on the dow front uniformity, streaking, voiding, and filler segregatio n were collected. The information was compared with the results predicted b y a new simulation code, plastic integrated circuit encapsulation-computer aided design (PLICE-CAD) under DARPA-funded development. The two-phase mode l of the combined resin and air takes into account geometrical factors such as bumps and die edges, together with boundary conditions in order to trac k accurately the propagation of the how fronts. The two-phase flow field is based on the volume-of-fluid (VOF) methodology embedded in a general-purpo se three-dimensional (3-D) flow solver.