Researchers are adapting the same methods used in fusion-energy research to create extremely thin plasma beams for a new class of nanolithography required to make future computer chips.

Current technology uses ultraviolet light to create the fine features in computer chips in a process called photolithography, which involves projecting the image of a mask onto a light-sensitive material, then chemically etching the resulting pattern.

"We can't make devices much smaller using conventional lithography, so we have to find ways of creating beams having more narrow wavelengths," said Ahmed Hassanein, the Paul L. Wattelet Professor of Nuclear Engineering and head of Purdue's School of Nuclear Engineering.

The new plasma-based lithography under development generates "extreme ultraviolet" light having a wavelength of 13.5 nanometers, less than one-tenth the size of current lithography, Hassanein said.

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. We are involved in optimizing conversion efficiency - reducing the energy requirements - and solving various design problems for the next-generation lithography."

Findings are detailed in a research paper scheduled to appear in the October-December 2009 issue of the Journal of Micro/Nanolithography, MEMS, and MOEMS. The paper was written by Hassanein, senior research scientist Valeryi Sizyuk, computer analyst Tatyana Sizyuk, and research assistant professor Sivanandan Harilal, all in the School of Nuclear Engineering.

"Nuclear engineer Ahmed Hassanein works at his Purdue lab, where researchers are adapting the same methods used in fusion-energy research to develop a new type of "nanolithography" for creating future computer chips. Supercomputers at the U.S. Department of Energy's Argonne National Laboratory are needed to run simulations critical for the research.

The technology revolves around extremely thin plasma beams for making tiny features in future computer chips and continuing Moore's law, an unofficial rule stating that the number of transistors on integrated circuits, or chips, doubles about every 18 months. (Credit: Purdue University photo/Vincent Walter)"

Source: Purdue University