Thermal Enhancements for a Thin Film Chip Carrier

This paper describes the development effort of a thermal enhancement technique targeted for single chip, thin film carriers. The test package in this paper consisted of a 7.5 mm by 7.5 mm chip bonded to a high lead count organic tape substrate using tape automated bonding (TAB). Because of high chip power requirements, a thermal enhancement consisting of a heat sink bonded to the chip with a thermally conductive epoxy was developed. The objectives of the current paper were to develop the appropriate heat sink, thermal adhesive, and assembly process for the heat management system. The thermal performance of the package was evaluated in both natural and forced convection environments. Reliability measurements were taken to ensure the chip to heat sink interface and the overall package withstood the required stresses without significant performance deterioration. These stresses included standard accelerated thermal cycling (ATC), ship shock, mechanical torque and vibration, and chemical exposure.