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Proceedings Paper

Mix-and-match interferometric and optical lithographies for nanoscale structures
Author(s): Saleem H. Zaidi; Steven R. J. Brueck; Thomas A. Hill; Richard N. Shagam
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Paper Abstract

Optical lithography (OL) is the manufacturing base for patterning of semiconductor integrated circuits (IC). Fundamental limits on optical imaging at features below 200- nm potentially limit its continued applicability. Interferometric lithography (IL) techniques provide a demonstrated, low-cost, large area nanoscale patterning capability with dense feature resolution to approximately 50 nm. An important next step is demonstrating the capability of applying IL to ann existing pattern defined by OL. We report on a mix-and-match scheme for writing a critical layer in an electrical linewidth test structure. Two important issues are the accuracy and the overlay of the grids for the two exposure techniques. Moire techniques are used to evaluate the grid absolute accuracy for Il with expanding spherical wavefronts. For a 1-m distance to the wafer plane, the period variation is less than 5 X 10-5 over a 1 cm2 field leading to a placement error of +/- 60 nm over the field. This error scales as the inverse square of the distance to the wafer plane and can be reduced to arbitrarily levels. Collimation will eliminate this systematic error to the extent that lens aberrations are compensated. Preliminary experimental results in qualitative agreement with the analysis are presented.

Paper Details

Date Published: 5 June 1998
PDF: 8 pages
Proc. SPIE 3331, Emerging Lithographic Technologies II, (5 June 1998); doi: 10.1117/12.309575
Show Author Affiliations
Saleem H. Zaidi, Univ. of New Mexico (United States)
Steven R. J. Brueck, Univ. of New Mexico (United States)
Thomas A. Hill, Sandia National Labs. (United States)
Richard N. Shagam, Sandia National Labs. (United States)

Published in SPIE Proceedings Vol. 3331:
Emerging Lithographic Technologies II
Yuli Vladimirsky, Editor(s)

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