Abstract

effort was aimed at combining the advantages of vapor chambers or two-dimensional (2D) heat pipes and solid conductors by building thin, high effective thermal conductiv-ity, flat heat pipes out of materials with thermal expansion coefficients that match current electronic devices. In addition to the temperature uniformity and minimal load-driven temperature variations associated with such two phase systems, in their defined paramet-ric space, flat heat pipes are particularly attractive for Department of Defense and com-mercial systems because they offer a passive, reliable, light-weight, and low-cost path for transferring heat away from high power dissipative components. However, the difference in thermal expansion coefficients between silicon or ceramic microelectronic components and metallic vapor chambers, as well as the need for a planar, chip-size attachment sur-face for these devices, has limited the use of commercial of the shelf flat heat pipes in this role. The primary TGP goal was to achieve extreme lateral thermal conductivity, in the range of 10 kW/mK–20 kW/mK or approximately 25–50 times higher than copper and 10 times higher than synthetic diamond, with a thickness of 1 mm or less. [DOI: 10.1115/1.4028890] 1