IBM researchers are using biological principles to cool computer chips with the aim of making faster, denser computer systems.
Inspired by the way liquids are drawn away in tree leaves, roots or the human circulatory system, scientists developed a chip cap with a network of tree-like branched channels on its surface. When pressure is applied, it remains uniform and spreads evenly across the chip, with 10 times better heat transport than with current cooling methods.
A special paste is used at the interface between the hot chip and the cooling components. The technique, called “high thermal conductivity interface technology,” draws twice as much heat off the chips than today’s fan-based methods.
That leads to a significant savings in energy, the cost of which has been a significant problem, especially in the total cost of ownership in data centers.
“We’re already at the point according to some market analysts where it costs significantly more to support a server than it does to buy the server over the life of the server,” said Charles King, principal analyst at Pund-IT. “More than half of that cost is related to energy,” he said.
The new technique will allow chip manufacturers to design increasingly more powerful and denser chips, smaller and with more transistors in accordance with Moore’s Law. As chips scale smaller they tend to run hotter, which is why the new cooling methods are needed, King said.
“These next generation chips are going to be producing tremendous amounts of heat,” he said. “You simply can’t blow enough air through the system to remove the heat adequately.”
Future in Mind
IBM’s new technique was developed at the IBM Zurich Research Laboratory. Researchers there are currently testing even more efficient methods, experimenting with jets of water in an approach called direct jet impingement.
In a perfectly closed system so that no coolant gets into the electronics, water is squirted onto the back of the chip and sucked back off again. Up to 50,000 tiny nozzles are used in a complicated tree-like branched return architecture.
Current high-performance chips generate 100 Watts per square centimeter, which is one order of magnitude higher than a hotplate. Future generations of chips could get as hot as the surface of the sun, or approximately 6,000 degrees Celsius if not cooled, according to IBM.