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Proceedings Paper

Stepper Overlay Calibration Using Alignment To A Latent Image
Author(s): Karl W. Edmark; Christopher P. Ausschnitt
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Paper Abstract

We describe a method which minimizes the time required to set up and sustain optimum overlay performance of the DSW step-and-repeat system throughout a product wafer run. Improvement in both system performance and productivity is realized. Fundamental to the technique are the latent image formed by the exposure of photoresist, the AWA' global alignment system and the laser-metered stages of the DSW® system. We eliminate the need to develop wafers and to read verniers during the DSW® system set-up. Furthermore, we demonstrate the potential for on-the-fly calibration using product reticles and product wafers. The approach is generally applicable to the overlay calibration of optical exposure tools.

Paper Details

Date Published: 23 July 1985
PDF: 11 pages
Proc. SPIE 0538, Optical Microlithography IV, (23 July 1985); doi: 10.1117/12.947752
Show Author Affiliations
Karl W. Edmark, GCA Corporation (United States)
Christopher P. Ausschnitt, GCA Corporation (United States)

Published in SPIE Proceedings Vol. 0538:
Optical Microlithography IV
Harry L. Stover, Editor(s)

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