Hot chips? Call in the plumber!

Stephen Withers
Friday, 06 June 2008 08:42

Your IT - Home IT

Is Mario working at IBM's research lab? Surely only a crazy plumber would think of building microscopic water pipes inside silicon chips.

But that's just what scientists at IBM's Zurich laboratory have done, in conjunction with Berlin's Fraunhofer Institute (home of the ubiquitous MP3 format).

IBM has been working on chip stacking, a technique that transforms the usual 2D arrangement of circuit elements into a 3D structure. Bringing the devices closer together allows the chip to run faster as the signals don't need to travel as far. Furthermore, the 3D arrangement allows for more connections between the different components, providing additional opportunities to boost performance.

The problem is that increasing the thickness makes it harder to dissipate the heat that it generates. A 3D chip stack just 2cm square and 1mm thick might generate as much as one kilowatt - similar to an electric fan heater on its low setting.

"As we package chips on top of each other to significantly speed a processor's capability to process data, we have found that conventional coolers attached to the back of a chip don’t scale. In order to exploit the potential of high-performance 3-D chip stacking, we need interlayer cooling," said Thomas Brunschwiler, project leader at IBM’s Zurich Research Laboratory.

"Until now, nobody has demonstrated viable solutions to this problem."

So just how does this in-chip water cooling achieved? The answer may be found on the next page.