Test cell for a novel planar MEMS loop heat pipe based on coherent porous silicon

Work towards the development of an innovative, potentially high power density, MEMS loop heat pipe is in progress at the Center for Microelectronic Sensors and M E M S at the University of Cincinnati. The design of the loop heat pipe is based upon the very unique coherent porous silicon technology, a technique in which vast arrays of micrometer - sized through - holes are photo - electrochemically etched into a silicon wafer perpendicular to the (100) surface. The initial mathematical model, the design, fabrication and characterization of the device in the open loop configuration were previously reported at this conference, STAIF 2002. This paper begins with a very brief explanation of the device and its theory of operation. The design of the device components and their production utilizing the various techniques of microelectronic and microelectromechanical fabrication are presented. The modifications made to the photon - induced, electrochemical etch process, which significantly increase the etch rate of the pores, are explained. Attention is given to the mathematical model of the planar, MEMS, loop heat pipe with respect to the generation of the dimensions of the components through a summary of the recent advances. The emphasis of this paper is upon the design, construction and the characterization of the evacuated closed loop test cell structure.