Micro Heat Pipe Manufacturing Technology of Vacuuming and Filling Work Fluid

Abstract

Micro heat pipe is an apparatus with high effective heat transfer efficiency for complementary metal oxide semiconductor (CMOS) chips which have high heat flux in a limited space, and its manufacturing technology of vacuuming and filling working fluid is critical for its quality. The conventional micro heat pipe manufacturing technology of first vacuuming then filling working fluid (FVFW) is analyzed, the manufacturing technology of first filling working fluid then vacuuming (FWFV) is proposed. The principle of the technology and the theory for second vacuuming are analyzed. Furthermore, Mathematical models are established, including the additional liquid inventory, the volume of work dead zone and the length of non-condensable gas. Comparison between FWFV and FVFW is investigated. Some copper-water grooved-wick micro heat pipes which are fabricated by FWFV are tested to validate FWFV. It shows that the performance of the micro heat pipe with additional liquid inventory improves 12 times that of without additional liquid inventory. Therefore, the micro heat pipe manufacturing technology of FWFV can manufacture micro heat pipes successfully.