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Proceedings Paper

High-performance wafer stage: simplification delivers performance
Author(s): John F. Cameron; Jacqueline A. Seto; Lawrence A. Wise
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Paper Abstract

A mechanically simple, high performance wafer stage is discussed in this paper, including detailed descriptions of the mechanical construction, laser gauging system, electrical configuration and servo control. This stage provides for simultaneous X, Y, and theta motion with an inherently rigid, monolithic platform propelled by Sawyer linear motors. The measurement of position, for closed loop control, is provided by four axes of interferometric laser gauging. Position control is accomplished with a power-efficient, robust, digital servo system. The enhanced wafer positioning precision capability of this stage offers accurate alignment in enhanced global alignment mode (EGA). Due to its low mass (weighing less than 18 lb.) the stage delivers optimal acceleration, velocity, and settling. The stage has been incorporated in a 1:1 photolithographic wafer stepper. Its simplistic design incorporates a minimum number of moving parts and provides high reliability and low maintenance. This stage offers significant productivity advantages as demonstrated by the throughput specifications and the stage settling data reported in this paper. Overlay data using this system operating in EGA mode is also included.

Paper Details

Date Published: 1 June 1992
PDF: 15 pages
Proc. SPIE 1674, Optical/Laser Microlithography V, (1 June 1992); doi: 10.1117/12.130340
Show Author Affiliations
John F. Cameron, Ultratech Stepper (United States)
Jacqueline A. Seto, Ultratech Stepper (United States)
Lawrence A. Wise, Ultratech Stepper (United States)


Published in SPIE Proceedings Vol. 1674:
Optical/Laser Microlithography V
John D. Cuthbert, Editor(s)

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