Making Micromachines On The Cheap

STARTING MORE THAN 10 YEARS AGO, electrical and mechanical engineers joined forces to craft minuscule gears, switches, and power supplies for next-generation electronic devices. Micromachines have now arrived in the form of air-bag sensors and other tiny gizmos. But prices have remained high because the devices are often made in costly semiconductor cleanrooms.

Adam Cohen, an engineer at the University of Southern California's Information Sciences Institute, has a different production approach that could drastically reduce costs. Dubbed Efab, for electrochemical fabrication, the process relies on a technique known as rapid prototyping, in which engineers build up devices layer by layer, rather than precision-machining them from silicon.

The most common devices currently produced by rapid prototyping are plastic components a few centimeters in diameter. Cohen hopes to do much better. His team has already built tiny chains consisting of up to 12 metal layers. Soon, the team plans to stack up thousands of layers to make sophisticated 3-D components that are far smaller than the width of a human hair. These could be constructed directly on top of other semiconductors. Efab, according to Cohen, could reduce the cost of some microcomponents by a factor of 100.