Liquid Metal-Filled Micro Heat Pipes for Thermal Management of Solid-State Devices

Microelectromechanical systems technology can be used to realize micro heat pipes (MHPs) for thermal management of solid-state devices in industrial applications. Similar to the uses of traditional heat pipes in the macroworld, MHPs provide a passive and efficient way of spreading heat away from a heat source. MHPs have recently been demonstrated using alcohol or water as the working fluid. Liquid metals have superior thermal properties compared to water or alcohol and have been used in macroscale heat pipes for many years. However, liquid metal working fluids have not previously been demonstrated in MHPs. By utilizing indium cold welding of micromachined silicon structures, liquid metal-filled MHPs were successfully fabricated and then evaluated. Their performance was proven to be superior to the performance of equivalent water-filled MHPs.