Improving Heat Transfer from a Flip-Chip Package

The lid of an ASIC package can significantly increase the temperature of the die by impeding heat transfer. In flip-chip packages the backside of a die can be exposed by eliminating the lid, thus allowing a heat sink to be attached directly. Numerical finite difference methods and experimentation were used to investigate the differences between lidded and lidless flip-chip designs. The results demonstrate that a lidless package is a superior design because of the increased thermal conductivity between the die and the heat sink.

by Cullen E. Bash and Richard L. Blanco