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Proceedings Paper

Detection and refractive index identification of submicron particles on surfaces
Author(s): Marc A. Taubenblatt; John Samuel Batchelder
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Paper Abstract

Inspection for contaminant particles on surfaces is of major interest in the semiconductor industry as well as many others. We have developed an optical inspection instrument which detects particles as small as 65 nm and give information about the refractive index as well. Such information can be used to identify contaminant particles leading to more rapid identification of the source. The instrument is based on a scanned laser Nomarski interferometer, and measures differential phase and amplitude over an inspected area. We have previously shown that the forward scattered light from a small particle (in this case in liquid) interferes with the incident beam to produce a phase shift and amplitude change (extinction) dependent on the particle size and refractive index. This method is also applicable to surfaces by using a reflection mode. Similar to ellipsometry, plotting phase shift against extinction can provide information on both size and refractive index. We have analyzed particles on a silicon surface for a range of compositions, and found that particles can be sorted into refractive index classes such as low index, moderate index and metals.

Paper Details

Date Published: 28 May 1993
PDF: 9 pages
Proc. SPIE 1821, Industrial Applications of Optical Inspection, Metrology, and Sensing, (28 May 1993); doi: 10.1117/12.145532
Show Author Affiliations
Marc A. Taubenblatt, IBM Thomas J. Watson Research Ctr. (United States)
John Samuel Batchelder, IBM Thomas J. Watson Research Ctr. (United States)


Published in SPIE Proceedings Vol. 1821:
Industrial Applications of Optical Inspection, Metrology, and Sensing
Gordon M. Brown; Kevin G. Harding; H. Philip Stahl, Editor(s)

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