Thermosonic flip-chip bonding for an 8×8 VCSEL array

The introduction of ultrasonic energy to the flip-chip bonding process has the potential to increase the speed of the operation while at the same time lowering the physical stresses on the bonded components. This is a significant consideration for the optoelectronics components that will be used in many single and multi-chip module assemblies. However, at this time, while many empirical studies have shown that thermosonic flip-chip bonding is feasible, there is a lack of detailed understanding of the effects of the ultrasonic energy on the bonding results. At the University of Colorado, we are conducting experiments and developing models that will provide a sound understanding and a rational basis for thermosonic flip-chip bonding. This report details our findings concerning the aspects important to the development of thermosonic flip-chip bonding technology