Cure of underfills in flip chips using microwave

Underfill materials cured thermally as well as by microwave have been studied. The underfill material composed of cycloaliphatic epoxy and anhydride is studied in this paper. Thermo-mechanical properties of the underfill have been evaluated using a thermo-mechanical analyzer (TMA), a thermal gravimetric analyzer (TGA), and a dynamic mechanical analyzer (DMA). The experimental results show that the cure kinetics and mechanical properties of the underfill material are not changed by energy sources. Moreover, a three dimensional finite element method was developed to simulate curing of underfills using microwave. The present numerical results show that the position of the substrate can affect natural frequencies and field distributions significantly.