Share Email Print

Proceedings Paper

Investigation of cross-field wavefront aberrations of KrF lithography exposure systems as a function of excimer laser bandwidth
Author(s): Ivan Lalovic; Armen Kroyan; Nigel R. Farrar; Dennis Taitano; Paolo Zambon; Adlai H. Smith
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

Quantification of projection lens aberrations in lithographic exposure systems has gained significant importance due to more stringent critical dimension control and image fidelity requirements. As linewidths shrink, the impacts of wavefront aberrations on imaging become more pronounced. Therefore, minimization of the wavefront aberrations across the image field is desired and has led to the development of a number of measurement approaches. The proposed techniques have been evaluated extensively for characterization and specification of lens systems, adjustments, matching, and periodic control and monitoring of lithography systems for volume production. In this study, we discuss the contribution of excimer laser bandwidth towards lens aberrations. We carry out simulations of the effects of image contrast on conventional projection patterning, to evaluate the degree of aberation-induced linewidth changes depending on image contrast level. Also, experiments have been conducted to measure the response of wavefront error as a function of spectral bandwidth for a 0.6NA stepper and scanner. Depending on the field location, a positive relationship is observed between the measured aberration level and bandwidth. We propose a formalism to correlate the aberration measurement with aberration response to wavelength offset, presented elsewhere.[2] The wavefront error, in this work, is measured using a commercially available in-situ interferometric technique, whose response is largely insensitive to focal plane changes and partial coherence.

Paper Details

Date Published: 14 September 2001
PDF: 10 pages
Proc. SPIE 4346, Optical Microlithography XIV, (14 September 2001); doi: 10.1117/12.435655
Show Author Affiliations
Ivan Lalovic, Cymer, Inc. (United States)
Armen Kroyan, Cymer, Inc. (United States)
Nigel R. Farrar, Cymer, Inc. (United States)
Dennis Taitano, KLA-Tencor Corp. (United States)
Paolo Zambon, Cymer, Inc. (United States)
Adlai H. Smith, Litel Instruments, Inc. (United States)

Published in SPIE Proceedings Vol. 4346:
Optical Microlithography XIV
Christopher J. Progler, Editor(s)

© SPIE. Terms of Use
Back to Top