Nextreme Seeks to Beat Heat
August 3 2006 – The smaller the geometry of the integrated circuit, the more tightly packed the transistors. And the more tightly packed the transistors, the hotter the chip can get.
When the process node hit 90 nanometers, thermoelectric problems became especially pronounced. But the heat is not spread evenly across the chip; there typically are one or two "hot spots," which need to be cooled more than the rest of the device. If not properly managed, hot spots impede a chip's performance and reliability.
Today the problem exists mainly in microprocessors, graphics processors and other high-end chips being manufactured at the smaller geometries. Tomorrow, when relatively cheap commodity chips are produced at the smaller geometries, they too will have hot spots.
The problem is not going away.
"The problem is the net result of continued miniaturization," observes Avram Bar-Cohen, a professor of engineering at the University of Maryland.
There are kludge design workarounds, but the most elegant solution is a microthermal electronic cooler. A microthermal electronic cooler is a bit of material the size of a piece of confetti that, when laid over the hot spots, can remove heat and cool just those spots. Bismuth telluride, commonly used in refrigeration units, is the current material of choice for the confetti.
Every semiconductor manufacturer ought to at least know about a startup company that is developing this technology. Nextreme Thermal Solutions, in Research Triangle Park, N.C., an 18-month-old startup with about $8 million in venture funding. Nextreme is a spin-off of a research project at RTI International, a nonprofit laboratory, which had been developing thermoelectric technology for a decade in collaboration with the U.S. Defense Advanced Research Projects Agency (DARPA) and the Office of Naval Research.
Jesko von Windheim, the CEO, says his company is already collaborating with a handful of major semiconductor manufacturers. The technology is a couple of years away from actual production, because chip manufacturers don't typically adopt a new technology such as this without putting it through a rigorous qualification period that can take two years. Von Windheim expects to start that qualification process with some chip companies in 2007 and expects his micro coolers to be found on chips by 2009.
"Using these thermoelectric devices is the most elegant approach to the hot spot problem," says Bar-Cohen. "They are inherently compatible with the microprocessors. They don't weigh much and have no moving parts, no noise and effectively no volume. You basically attach them to the back of the chip, and you are done."
Cooling the tempers of engineers frustrated by hot spots should be so simple.