Adhesion studies of model epoxy systems and commercial underfill resins

The fracture behavior of model epoxy systems and commercial underfill resins for flip chip assembly solder joint encapsulation has been studied. In some cases, the energy dissipation mechanisms are similar. The high filler loading makes detection of the subsurface damage difficult and more can be learned from the model systems. Thus far, we have determined that the same mechanisms that occur in the bulk also occur in adhesive joints. However, the extent of these mechanisms can vary. Currently, we are studying methods to increase the surface energy of polyimide and to improve adhesion.