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MIT Electrical Engineering and Computer Science
EECS Event |
Tuesday, October 2, 2001
4:00 PM (reception 3:30)
Edgerton Hall, Room 34-101
MTL VLSI Seminar
Abstract
Resolution limits for projection optical lithography are well known and well understood, but in the optical near field region these limits can be overcome. At the University of Canterbury we have been studying photolithography techniques that utilise exposure from evanescent fields close to metallic amplitude masks. Sub-diffraction-limited resolution has been achieved experimentally, and the theoretical resolution limits have been explored using vector electromagnetic near field simulations.
In this talk the issues affecting the fundamental resolution limits of near field photolithography will be explored. It is found that the exposure wavelength is of secondary importance in this regime, and that the properties of the mask are much more significant. Scaling to smaller feature sizes requires better resolution and control during mask manufacture, rather than the conventional (and costly) approach of driving the exposure wavelength deeper and deeper into the ultraviolet. Near field interference effects will also be discussed, and a proposal for spatial frequency doubling using Evanescent Interferometric Lithography (EIL) will be described. Finally, some recent results will be presented on the use of negative refraction and surface plasmons to improve further the resolution in the near field.