Embedded Heat Pipes in Ceramic Electronic Packages and Filling Process.

摘要

The development of a new technology for electronic cooling is described in this report. By integrating heat pipes directly within the ceramic substrate, effective thermal conduction for spreading heat in both radial and axial directions was achieved. Several prototype miniature heat pipes have been fabricated in HTCC and LTCC substrates in the Hybrid Lab at FTU using numerically controlled machining operations. The heat pipes use an axially grooved wick structure to facilitate transport of the working fluid from the condenser to the evaporator. Three liquid charging methods were developed in the Thermal Science Lab at FTU for accurate filling process and were proven to be practical. Experimental testing has been performed and more than 20 watts of heat were transported by the heat pipe that has a vapor space of 82.5 by 4.1 by 1.27 cu mm. In all cases, the temperature variation along the length of the substrate surface was less than 5 deg C. The heat pipe was found to have an effective thermal conductivity greater than 10,000 W/m-K, which is over 300 times hi her than that of the alumina it replaced within the substrate.