Silicon heat pipes used as thermal spreaders

An increase in power densities in electronic devices is a direct consequence of their miniaturization and performance improvements. We propose the use of flat miniature heat pipes with micro capillary grooves to spread heat flux across a heat sink. Models of the structure were developed to calculate heat transfer limitations and temperature drops. A brass/water prototype was fabricated to demonstrate the feasibility of heat spreading using this type of heat pipe. Simulation and experimental results obtained with the prototype are described. The dissipated power reached 110 W/cm² without heat transfer limitations. The results are then extended to the design of this type of heat pipe in silicon. Thermal performance was calculated. Simulation, experimental results and the fabrication process are presented.