Micro Heat Pipes

Abstract

The concept of combining phase-change heat transfer and microfabrication techniques to construct micro heat pipes for the dissipation of heat is due to Cotter [34]. Since the introduction of this idea, the proposed applications of micro heat pipes have expanded from the thermal control of localized heat generating devices such as laser diodes and infrared detectors to the removal of heat from the leading edges of stator vanes in turbines or the leading edges of hypersonic aircrafts. While not all the suggested applications have materialized, micro heat pipes have been fabricated, modelled and analysed. The larger of these systems have been implemented in commercially available products such as laptop computers or highprecision equipment. Indeed, most of the research work is still devoted to cooling of semiconductors chips. Micro heat pipes are used to eliminate hot spots, reduce temperature gradients, and improve chip reliability. The high power level currently possible, on the order of 100W/cm², together with the heat pipes being self-contained and self-starting make micro heat pipes an ideal heat transfer system. Furthermore, the introduction of newly developed CMOS-compatible techniques to integrate such thermal microsystems with microelectronic devices will surely enhance their range of applications.