Alternative curing methods for FCOB underfill

This paper explores the use of liquid immersion and vapor condensation curi ng as alternatives to conventional hot air oven curing of flip chip on boar d underfill. Heat transfer results suggest that both the liquid immersion a nd vapor condensation heating result in reduced cure times due to higher he at transfer results associated with these two techniques. Preliminary relia bility studies suggest that the two proposed rapid curing methods do not re sult in any increased failure rates or different failure mechanisms. In alm ost all the samples the failure mode was delamination of the underfill foll owed by solder fatigue failure.