A One Two Punch For Packing More On A Chip
OPTICAL LITHOGRAPHY IS HIGH TECH'S CAT with nine lives. Not long ago, chips "printed" by optical techniques--the mainstay for four decades--seemed to be on their last legs. By 2005, researchers thought, light simply could not draw ever-thinner lines for ever-faster chips.
But engineers have now found new life in the optical spectrum. It's called extreme ultraviolet (EUV) light--and TRW Inc.'s Space & Electronics Group has just uncorked a prototype system for generating EUV light.
Today's cutting-edge chips are printed with deep-UV lasers, which have wavelengths of around 200 nanometers. Because of physical limitations, deep UV can't print lines much thinner than 0.15 microns. (A human hair is about 100 microns wide.)
But light from TRW's EUV laser cuts a swath of only 13 nanometers. With EUV, printing lines finer than 0.1 micron will be a snap. In fact, EUV lasers are such a drastic improvement, says Thomas E. Romesser, vice-president for TRW's laser business, that they could extend optical lithography's reign for 10 more years.
New competition, however, could soon threaten even EUV optics. In laboratories, researchers can print lines as skinny as 0.01 micron using 4-nanometer X-rays. The hang-up has been that it took a huge synchrotron, or atom smasher, to generate those tiny X-rays.
Not anymore. JMAR Technologies Inc. in San Diego has just unveiled a file-cabinet-size system that produces 1-nanometer X-rays. Chairman John S. Martinez predicts that X-ray lithography will soon give optical equipment a run for its money.