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Proceedings Paper

Methods, error influences, and limits for the ultraprecise measurement of slope and figure for large, slightly nonflat, or steep complex surfaces
Author(s): Ingolf Weingaertner; Michael Schulz; Peter Thomsen-Schmidt
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Paper Abstract

The problem of measuring the slope and figure of large, slightly non-flat or steep complex surfaces with nanometer and sub-nanometer accuracy has not been generally solved. Existing systems such as interferometers, three-coordinate measuring machines and slope measuring facilities do not fulfil the requirements for very high accuracy: related topics will be discussed: intrinsically two-dimensional methods vs. scanning methods, external references and their influences, the kind of measurements signal, errors of scanning stages and their influences, whole-body movements of the artifact and their influences, long-time stability of the facility. Very recently, particular measurement principles have been proposed, which focus on the principles of traceability and avoidance of error influences and are intended for determining slope and figure with ultra- precision. These methods are based on the direct measurement of slope difference and curvature, and in contrast to other methods, are directly traced back to the base units. They do not depend on external references and offer the advantage that the errors of the stages and whole- body movement of the artifact do not influence the accuracy of measurement. Application of these methods eliminates the influences of the first- and second-order errors of the facility. In addition, absolute measurements are traced back to relative measurements and long-time stability is achieved by constant recalibration of the sensor. The question which remains to be answered and which will be discussed is that of the basic or natural limits of systems intended for measuring slope and figure.

Paper Details

Date Published: 2 November 2000
PDF: 12 pages
Proc. SPIE 4099, Optical Metrology Roadmap for the Semiconductor, Optical, and Data Storage Industries, (2 November 2000); doi: 10.1117/12.405814
Show Author Affiliations
Ingolf Weingaertner, Physikalisch-Technische Bundesanstalt Braunschweig und Berlin (Germany)
Michael Schulz, Physikalisch-Technische Bundesanstalt Braunschweig und Berlin (Germany)
Peter Thomsen-Schmidt, Physikalisch-Technische Bundesanstalt Braunschweig und Berlin (Germany)

Published in SPIE Proceedings Vol. 4099:
Optical Metrology Roadmap for the Semiconductor, Optical, and Data Storage Industries
Ghanim A. Al-Jumaily; Angela Duparre; Bhanwar Singh, Editor(s)

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