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Proceedings Paper

Comparison of PSD measurements using stray light sensors with PSD curves evaluated from topography of large AFM scans
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Paper Abstract

For monitoring processes of semi conductor or optical industry automatically, stray light sensors are employed for a fast surface san to measure rms, defects, and contamination on surfaces. Surfaces can be characterized by the BRDF. The BRDF is parametrized to classify different surfaces. Classification may be done with various pattern recognition tools, but up to now no proof exists that justifies any choice of classes found empirically. Of course, a basic quantitative, i.e. metrological understanding of stray light sensors is necessary, which could successfully be obtained after comparing BRDFs evaluated from AFM topography scans with smooth surfaces. The power spectrum of surface topographies sufficiently smooth to obey Rayleigh-Rice approximation is proportional to the BRDF. Surfaces obeying this approximation, however, may not include defects and contamination with lateral sizes smaller than the wavelength of the illuminating light employed in the stray light sensor. Thus the comparison was only carried out with specially prepared samples. We have measured the topography of large areas up to 600 micrometer X 100 micrometer with an AFM by patching several scans (up to 8) with overlap. BRDFs evaluated from AFM measurements agree well with BRDFs measured with a stray light sensor.

Paper Details

Date Published: 30 October 1998
PDF: 11 pages
Proc. SPIE 3426, Scattering and Surface Roughness II, (30 October 1998); doi: 10.1117/12.328475
Show Author Affiliations
Dorothee Hueser, Univ. of the Federal Armed Forces (Germany)
Thomas Rinder, Univ. of the Federal Armed Forces (Germany)
Hendrik Rothe, Univ. of the Federal Armed Forces (Germany)

Published in SPIE Proceedings Vol. 3426:
Scattering and Surface Roughness II
Zu-Han Gu; Alexei A. Maradudin, Editor(s)

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