A Conduction-Cooled Module for High-Performance LSI Devices

The advent of LSI chip technology makes possible significantly increased performance and circuit densities by means of large-scale packaging of multiple devices on a single multi-layer ceramic (MLC) substrate. Integration at the chip and module levels has resulted in circuit densities as high as 2.5×10
⁷
circuits per cubic meter, with the necessity of removing heat fluxes on the order of 100 kW/m
²
. This paper describes the development and implementation of a novel packaging concept which meets the stringent and highly interactive demands on cooling, reliability, and reworkability of LSI technology. These requirements resulted in an innovative packaging approach, referred to as the thermal conduction module (TCM). The TCM uses individually spring-loaded “pistons” that contact each chip with helium gas, the conducting medium for removing heat efficiently. A dismountable hermetic seal makes multiple access possible for device and substrate rework, while ensuring mechanical and environmental protection of critical components. A wide range of thermal, mechanical, and environmental experiments are described with analytical and computer models. The one-dimensional approach used in the previous paper by Chu et al. is extended to three-dimensional computer modeling. Simulations of expected chip temperature distributions in the IBM 3081 Processor Unit are discussed. Enhanced thermal performance of the advanced packaging concept for future applications is also indicated.