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Proceedings Paper

Autoalignment In Step-And-Repeat Wafer Printing
Author(s): Ronald S. Hershel
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Paper Abstract

A fully automatic through-the-lens alignment method is described for use in step-and-repeat projection aligners. The method utilizes dark field illumination of the wafer, which is aligned to the reticle. It is shown that 2.5 pm wide alignment marks that are 2 mils in length provide an ample signal-to-noise ratio for 0.1 pm alignment accuracies. Various contributions to alignment error are examined such as the visibility of the alignment features, surface scatter on the wafer, and shot noise in the detected signal. Applications of these results to x, y, and theta alignment in step-and-repeat printing are offered.

Paper Details

Date Published: 17 July 1979
PDF: 9 pages
Proc. SPIE 0174, Developments in Semiconductor Microlithography IV, (17 July 1979); doi: 10.1117/12.957178
Show Author Affiliations
Ronald S. Hershel, University of Arizona (United States)


Published in SPIE Proceedings Vol. 0174:
Developments in Semiconductor Microlithography IV
James W. Dey, Editor(s)

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