Making wafers faster by making features smaller

December 14, 2010

Washington, D.C. (December 14, 2010) -- The manufacturing of semiconductor wafers used in all types of electronics involves etching small features onto a wafer with lasers, a process that is ultimately limited by the wavelength of the light itself. The semiconductor industry is rapidly approaching this fundamental limit for increasing the speed of the microchip. The development of a new intense 13.5-nm (extreme ultraviolet or EUV) light source will resolve this issue by reducing the feature size by an order of magnitude or so, according to Purdue researchers in the Journal of Applied Physics.

One way to generate this wavelength of light is to bombard tin (Sn) and lithium (Li) targets with laser beams to create an intensely bright plasma; Sn and Li are good candidates because their plasmas emit efficiently in the 13.5 nm region, says Purdue graduate student Ryan Coons. He and his colleagues used spectroscopy and a Faraday cup to analyze the emission features and debris produced in laser-produced tin and lithium plasmas, and others in his group modeled their physical processes.

In a detailed comparison of the atomic and ionic debris, as well as the emission features of Sn and Li plasmas, the group's results show that Sn plasmas produce twice as much emission as that of Li. However, the kinetic energy of Sn ions is considerably higher, though with a lower flux. More work is needed to perfect the development of this technology.
The article, "Analysis of atomic and ion debris features of laser-produced Sn and Li plasmas" by Ryan W. Coons, Sivanandan S. Harilal, David D. Campos, and Ahmed Hassanein appears in Journal of Applied Physics. See:

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CAPTION: False-color images of the tin and lithium plasma plumes in EUV emission through a 7 to 15 nm filter, obtained under identical conditions.


Journal of Applied Physics is the American Institute of Physics' (AIP) archival journal for significant new results in applied physics; content is published online daily, collected into two online and printed issues per month (24 issues per year). The journal publishes articles that emphasize understanding of the physics underlying modern technology, but distinguished from technology on the one side and pure physics on the other. See:


The American Institute of Physics is a federation of 10 physical science societies representing more than 135,000 scientists, engineers, and educators and is one of the world's largest publishers of scientific information in the physical sciences. Offering partnership solutions for scientific societies and for similar organizations in science and engineering, AIP is a leader in the field of electronic publishing of scholarly journals. AIP publishes 12 journals (some of which are the most highly cited in their respective fields), two magazines, including its flagship publication Physics Today; and the AIP Conference Proceedings series. Its online publishing platform Scitation hosts nearly two million articles from more than 185 scholarly journals and other publications of 28 learned society publishers.

American Institute of Physics

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