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Proceedings Paper

Stage accuracy results using interferometers compensated for refractivity fluctuations
Author(s): Philip D. Henshaw; Pierre C. Trepagnier; Robert F. Dillon; Wouter Pril; Bas Hultermans
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Paper Abstract

Air refractivity changes, which include pressure, temperature, and composition effects, affect the performance of the Helium-Neon (HeNe) interferometer used to control the wafer and reticle stages of a step-and-scan lithography system. nanAlign is an auxiliary interferometer system designed to compensate for errors induced in a HeNe interferometer by refractivity changes. We conducted wafer exposure tests of nanAlign with 116 total wafers; 60 wafers with the same field order for each pass are discussed in this paper. We found that nanAlign measurements made on the x-axis could be used to improve the overlay in the y-axis. Over the entire ensemble of 60 wafers, the improvement of the x-axis was 0.6 nm, and the improvement of the y-axis was 0.4nm. Over the entire ensemble the worst wafers showed the most improvement, and there was some improvement on almost all wafers under a wide variety of conditions.

Paper Details

Date Published: 26 June 2003
PDF: 10 pages
Proc. SPIE 5040, Optical Microlithography XVI, (26 June 2003); doi: 10.1117/12.485475
Show Author Affiliations
Philip D. Henshaw, SPARTA, Inc. (United States)
Pierre C. Trepagnier, SPARTA, Inc. (United States)
Robert F. Dillon, Lumen Labs., Inc. (United States)
Wouter Pril, ASML (Netherlands)
Bas Hultermans, ASML (Netherlands)


Published in SPIE Proceedings Vol. 5040:
Optical Microlithography XVI
Anthony Yen, Editor(s)

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