Engineers at the University of California at Berkeley, are reporting a new way of creating computer chips that could revitalize optical lithography, the dominant patterning technique in integrated circuits manufacturing. The researchers were able to create line patterns only 80 nanometers wide at speeds up to 12 meters per second. They combined metal lenses that focus light through exciting electrons or plasmons on the lens' surface with a flying head that resembles the stylus on the arm of LP turntable and is similar to those used in hard disk drives.
"Utilizing this plasmonic nanolithography, we will be able to make current microprocessors more than 10 times smaller, but far more powerful," said Xiang Zhang, UC Berkeley professor of mechanical engineering and head of the research team. "This technology could also lead to ultra-high density disks that can hold 10 to 100 times more data than disks today."
To overcome the diffraction limit of light needed for lithography, the UC Berkeley researchers took advantage of a well-known property of metals: the presence at the surface of free electrons that oscillate when exposed to light. These oscillations are known as evanescent waves and are much smaller than the wavelength of light. The engineers designed a silver plasmonic lens with concentric rings that concentrate the light to a hole less than 100 nanometers in diameter. The researchers packed the lenses into a flying plasmonic head, so-called because it would "fly" above the photoresist surface during the lithography process.