The Heat Is On
As IC line drawings
scale down further, thermal management
and heat removal are becoming ever more
challenging—not only for the chip itself, but
also for the interconnects as they, too,
shrink. Heat in particular is a problem for
newer graphics and high-speed processors.
While heatsinks, fans, and blowers continue to advance, they'll no doubt lose effectiveness for future-generation ICs and packages. Even so, better heatsink and thermal
interface materials are lending a helping
hand. So are advanced thermal-management chips, liquid-cooling methods, and
nanoengineered thin-film materials (see
"Back to Cool School").
Cost, reliability, bulkiness, and quietness
still plague modern liquid-cooling methods.
According to Intel, the size and cost of liquid cooling is six times greater than air cooling. Asetek A/S claims to have narrowed
that cost ratio to 1 to 1.5 times that of air
cooling. Its proprietary IP liquid-cooling integrated pump, reservoir, and cold plate
comes in one compact device that's smaller than a traditional heatsink.
IBM has found a way to double or even
quadruple the amount of heat removed
from a given area by employing presentday, air-cooled methods. Using liquid
cooling and manifolds with high-thermal
conductivity interfaces, IBM has
achieved thermal power dissipation up to 24 W/in.2 from the present-day limits of
12 W/in.2 for air.
However, these developments are still at the lab. A void remains in the hardwareand software-tool departments, which
leaves designers scrambling to get a better understanding of thermal management issues. The good news is that the
design and packaging communities are on
top of the situation, in pursuit of appropriate solutions.
For more, see "Integration Via Semiconductor Packaging."