Alternative curing methods for FCOB underfill

This paper explores the use of liquid immersion and vapor condensation curing as alternatives to conventional hot air oven curing of flip chip on board underfill. Heat transfer results suggest that both the liquid immersion and vapor condensation heating result in reduced cure times due to higher heat transfer results associated with these two techniques. Preliminary reliability studies suggest that the two proposed rapid curing methods do not result in any increased failure rates or different failure mechanisms. In almost all the samples the failure mode was delamination of the underfill followed by solder fatigue failure.