/ To the naked eye, the object mounted on a postage stamp-size wafer and held aloft by a pair of tweezers is all but invisible. Even under a bright light, it looks like nothing more than a speck of dust. But magnified 160 times in an electron microscope, the speck begins to take on shape and function: a tiny gear with teeth the size of blood cells. "You have to be careful when handling these things," warns Kaigham Gabriel, an engineer at AT&T Bell Laboratories . "I've accidentally inhaled a few right into my lungs."
The miniaturization of technology, having made extraordinary progress in the 40 years since the invention of the transistor, is about to make another shrinking leap. Adapting the chipmaking equipment used to squeeze millions of electrical circuits onto slivers of silicon, researchers are creating a lilliputian tool chest of tiny moving parts: valves, gears, springs, levers, lenses and ball bearings. One team at the University of California, Berkeley, has already built a silicon motor not much wider than an eyelash that can rotate 500 times a minute.
Welcome to the world of microtechnology, where machines the size of sand grains are harnessed to do useful work. Huge numbers of microscopic sensors are already employed to measure the temperature, air pressure and acceleration of airplanes and automobiles. Delco Electronics alone sells 7 million silicon pressure sensors a year to its parent company, General Motors, for use in power-train controls and diagnostics. But scientists at Berkeley, Stanford, M.I.T., AT&T, IBM and a handful of other research centers around the world see much broader possibilities for minuscule machines. They envision armies of gnat-size robots exploring space, performing surgery inside the human body or possibly building skyscrapers one atom at a time. "Microelectronics is on the verge of a second revolution," says Jeffrey Lang, a professor of electromechanics at M.I.T. "We're still dreaming of applications."
A report to the U.S. National Science Foundation last year listed dozens of near-term uses for the new micromachines. Among them:
-- Tiny scissors or miniature electric buzz saws to assist doctors performing microsurgery.
-- Micro-optical systems to focus lasers to the precision required for fiber- optic communication.
-- Miniature machine parts that could drive a new generation of tiny tape recorders, camcorders and computers.
Engineers and industrialists are rushing to put the new technologies to use. M.I.T. has invested $20 million in a new fabrication facility for micromachining and microelectronics. Japan's Ministry of International Trade and Industry is considering allocating nearly $70 million for the development of medical microrobots. "I'm absolutely amazed at how fast this field has progressed," says George Hazelrigg, a program director at the NSF, the Government agency spearheading the U.S.'s micromechanics effort.