Cooling Down Hot Computer Chips

Dec. 16 -- The computer industry is in for a hot time — literally.

To produce ever-faster microprocessors, chip makers such as Intel and AMD have been cramming more and more microscopic transistors within the chips.

The current Pentium 4 chips, for example, have more than 42 million tiny electronic switches jammed into a space no larger than a postage stamp.

But such tightly packed processors also produce much heat — as much a 50-watt light bulb.

Getting rid of that excess heat, which can damage delicate components and cause data to be lost, is becoming increasingly problematic. Already, some high-end desktop computers are using tiny, sophisticated water-cooling systems to beat the heat.

Scientists at Sandia National Laboratories in Albuquerque, N.M., have been working on an elegant solution for the military that could soon find its way to desktop and laptop computers.

A Mini-Maze of Methanol Pipes

The device was developed under a joint project with researchers at the Georgia Institute of Technology to figure out how to cool military electronics — radar systems and portable battlefield computers.

The "smart heat pipe" is a simple, flat copper plate that contains tiny hollow flat channels. The "pipes" measure about 7 microns thick — about the depth between the individual ridges of a human fingerprint — and carry liquid methanol.

When the plate is bonded to the microprocessor, the methanol is drawn to the hot spots by capillary action, much like the way kerosene travels up a wick. The heat vaporizes the methanol into gas, which naturally moves away from the hot spots.

The gas can be directed to take the heat to cooler spots — say the sides of the plate. As the gas cools, it condenses back to liquid and is drawn back to the hot spots to start the cooling process over.

Simple to Make, Easy to Add

Michael Rightley, principal member of the technical staff at Sandia, says that in development tests so far, the "smart heat pipe" has had twice the thermal conductivity of standard copper plates of similar size.