A systems approach to the reduction of thermal resistance in microelectronics packaging.

摘要

Passive cooling of flip chip devices involves the use of heat spreaders and heat sinks that are attached to the backside of the semiconductor device through thermal interface materials (TIMs). The interface material layers offer the maximum resistance (up to 70% of the total thermal resistance) to heat dissipation from the semiconductor device. The enhancement of the performance of this link in the heat dissipation network, which is the closest to the semiconductor device and most critical, is vital to effectively manage the increasing power densities of semiconductor devices.; A reduction in resistance to heat dissipation across a thermal management subsystem (TIM system), comprising of the TIM, the interface between the TIM and the silicon backside, and the interface between the TIM and the heat spreader, is the crux of this research. A systematic study of the various factors that affect the system-level performance of TIMs was undertaken to develop efficient techniques for thermal performance enhancement.; The thermal performance of TIM systems was enhanced through the development of low thermal resistance TIMs, modification of the characteristics of the heat spreader and die surfaces, and the study of TIM assembly process parameters. The avenues that were developed in this research can be applied independently to reduce the thermal resistance of a TIM system or applied in a complementary manner to realize even greater reductions in thermal resistance. The thermal resistance of a current TIM system was reduced by as much as 70% through the application of these techniques.