Currently chip makers use ultraviolet light to create the fine features in computer chips in a process called photolithography and then chemically etch the pattern.
Since even smaller scale nanolithography will be needed to continue advances in computer technology and extend Moore's law, researchers have been scratching their heads to work out how they can do it.
Ahmed Hassanein, the Paul L. Wattelet Professor of Nuclear Engineering and head of Purdue's School of Nuclear Engineering, said that plasma-based lithography he has under development generates 'extreme ultraviolet' light having a wavelength of 13.5 nanometers, less than one-tenth the size of present beams.
Currently nuclear engineers and scientists at Purdue and the U.S. Department of Energy's Argonne National Laboratory are working to improve the efficiency of two techniques for producing the plasma. One approach uses a laser and the other 'discharge-produced' method uses an electric current.
"In either case, only about 1 to 2 percent of the energy spent is converted into plasma," Hassanein said. "That conversion efficiency means you'd need greater than 100 kilowatts of power for this lithography, which poses all sorts of engineering problems." Not to mention really big electric bills if scaled up for mass-production.
Currently he is involved in optimising conversion efficiency to reduce the energy requirements, and solving various design problems for what could be the next-generation of chip lithography.
In a research paper to appear in the October-December 2009 issue of the Journal of Micro/Nanolithography, MEMS, and MOEMS, Hassanein describes the laser method that creates plasma by heating xenon, tin or lithium. The plasma produces high-energy photons of extreme ultraviolet light.
Plasma's electrical conductivity means that the boffins can use magnetic fields to shape and control them, forming beams, filaments and other structures.
This is the same technique being used in experimental fusion reactors to keep plasma-based nuclear fuel from touching the metal walls of the containment vessel, thus enabling the plasma to be heated to the extreme temperatures required for fusion reactions.