In the DARPA Thermal Ground Plane (TGP)
program[1],we are developing a new thermal technology
that will enable a monumental thermal technological leap
to an entirely new class of electronics, particularly
electronics for use in high-tech military systems. The
proposed TGP is a planar, thermal expansion matched heat
spreader that is capable of moving heat from multiple
chips to a remote thermal sink. DARPA’s final goals
require the TGP to have an effective conductivity of
20,000 W/mK, operate at 20g, with minimal fluid loss of
less than 0.1%/year and in a large ultra-thin planar package
of 10cmx20cm, no thicker than 1mm. The proposed TGP
is based on a heat pipe architecture[2], whereby the
enhanced transport of heat is made possible by applying
nanoengineered surfaces to the evaporator, wick, and
condenser surfaces. Ultra-low thermal resistances are
engineered using superhydrophilic and superhydrophobic
nanostructures on the interior surfaces of the TGP
envelope. The final TGP design will be easily integrated
into existing printed circuit board manufacturing
technology. In this paper, we present the transport design,
fabrication and packaging techniques, and finally a novel
fluorescence imaging technique to visualize the capillary
flow in these nanostructured wicks.United States. Defense Advanced Research Projects Agency (SSC SD Contract No. N66001-08-C-2008
