Thursday, June 05, 2008

IBM developing miniature pipes of water for chip cooling

By Associated Press

Since a computer microprocessor is veined with electric circuitry, it might seem like a bad place to put water. But IBM Corp. researchers believe that sloshing water through hair-thin pipes inside chips will solve a vexing problem facing next-generation computers.

That problem is heat.

As chips get smaller and smaller, cramming more processing power into ever-tinier spaces, the heat thrown off by the miniature circuits becomes harder to manage. Cooling measures used now to avoid chip meltdowns, including "heat sinks" made from heat-absorbing materials, might not work on tinier scales.

In fact, in a future microprocessor design IBM is exploring -- in which chips are stacked vertically to save space and enhance performance, rather than arrayed next to each other -- the heat-to-volume ratio exceeds that of a nuclear reactor.

To address that, IBM researchers say they could pipe water in between chips that are sandwiched together. The system, which IBM planned to explain Thursday at a technical conference, uses pipes that are just 50 microns wide -- 50 millionths of a meter. The tiny tubes are sealed to prevent leaks and electrical shorts.

Even these micro amounts of water can handle prodigious cooling chores, because water is much more efficient than air at absorbing heat. That is why some high-end computers long have used water cooling. The new trick here is that IBM expects to do it at the miniature scale, inside chips.

"It's never been applied this close to the heart of the matter," said analyst Richard Doherty of the Envisioneering Group.

Yogendra Joshi, an engineering professor at the Georgia Institute of Technology, said aspects of IBM's approach already have been shown by other researchers. But he said the company deserves credit for trying to push the idea toward commercialization.

"There has been a great aversion to piping liquids through electronics," Joshi said. "That's understandable."

However, IBM's tiny pipes aren't out of the lab yet. They're at least five years from becoming available.