Blowing in the ionic wind: Cool chips promise more powerful computers, advanced applications

Researchers are showing off technology that promises to increase the cooling rate of computer chips by as much as 250%.  Purdue University researchers, in work funded by Intel are developing tiny "ionic wind engines” that when used in combination with a conventional computer fan, can enhance the fan's effectiveness by boosting airflow over the surface of a computer chip. The new technology could ultimately help engineers design thinner laptop computers that run cooler than today's machines. Advanced cooling technologies are needed to help industry meet the conflicting goals of developing more compact and lightweight computers that are still powerful enough to run high-intensity programs for video games and other graphics-heavy applications. As performance increases there is typically a corresponding increase in heat.  Heat can  not only hinder performance, but also could damage or destroy delicate circuitry. The experimental ionic cooling device works by generating ions - or electrically charged atoms - using electrodes placed near one another, researchers said in a release. The device contained a positively charged wire, or anode, and negatively charged electrodes, called cathodes. The anode was positioned about 10 millimeters above the cathodes. When voltage was passed through the device, the negatively charged electrodes discharged electrons toward the positively charged anode. Along the way, the electrons collided with air molecules, producing positively charged ions, which were then attracted back toward the negatively charged electrodes, creating an "ionic wind," researchers stated. This breeze increased the airflow on the surface of the experimental chip."Other experimental cooling-enhancement approaches might give you a 40% or a 50% improvement," said Suresh Garimella, a professor of mechanical engineering at Purdue. "A 250% improvement is quite unusual."The new cooling technology could be introduced in computers within three years if researchers are able to miniaturize it and make the system rugged enough. IBM, AMD, Intel and others are scrambling to find new and improved ways to keep chips cool. For example, scientists at IBM's Zurich Research Laboratory have developed a glue-application technique used to assemble chips that will keep them running cooler, the company said.  Glues are used to bind the semiconductor packages, such as microprocessors and chipsets, with cooling elements that disperse the heat generated by today's powerful chips. However, current glues, which are embedded with microscopic particles of metal or ceramics to help transfer heat, continue to be an obstacle to efficient heat dissipation, IBM said. Scientists at IBM's Zurich lab discovered that the problem lies in how the glue is applied. They observed that when a chip is attached to the cooling element of a semiconductor package, a cross formed in the glue as the microscopic particles it contains piled up. This prevents the glue from spreading evenly. They overcame this problem by creating tiny channels in the base of the heatsink that help the glue to flow properly. The result: a thinner layer of glue that helps to disperse heat three times more efficiently, IBM said.According to Purdue researchers, conventional cooling technologies are limited by a principle called the "no-slip" effect - as air flows over an object, the air molecules nearest the surface remain stationary. The molecules farther away from the surface move progressively faster. This phenomenon hinders computer cooling because it restricts airflow where it is most needed, directly on the chip's hot surface.

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