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Proceedings Paper

Pupil wavefront manipulation to compensate for mask topography effects in optical nanolithography
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Paper Abstract

As semiconductor nanolithography is pushed to smaller dimensions, process yields can suffer from three dimensional sub-wavelength imaging effects. Mask topography can influence the propagating diffracted field causing errors such as pitch dependent defocus and degraded useable depth of focus (UDOF). In this work, the compensation of diffracted phase error is realized through the manipulation of the wavefront in the projection lens pupil. Mask exposure data is presented showing how such manipulation can increase the UDOF for several mask structure types, leading to UDOF improvement between 18% and 83%. An analytical model is presented to understand trends seen in experimental data through pitch. Results also show that an asymmetric wavefront can be tuned to particular geometries, providing a UDOF improvement for line ends under restricted processing conditions.

Paper Details

Date Published: 12 April 2013
PDF: 12 pages
Proc. SPIE 8683, Optical Microlithography XXVI, 86830G (12 April 2013); doi: 10.1117/12.2010034
Show Author Affiliations
Monica Kempsell Sears, Rochester Institute of Technology (United States)
Bruce W. Smith, Rochester Institute of Technology (United States)

Published in SPIE Proceedings Vol. 8683:
Optical Microlithography XXVI
Will Conley, Editor(s)

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