28 May 1993 Detection and refractive index identification of submicron particles on surfaces
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Proceedings Volume 1821, Industrial Applications of Optical Inspection, Metrology, and Sensing; (1993) https://doi.org/10.1117/12.145532
Event: Applications in Optical Science and Engineering, 1992, Boston, MA, United States
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.
© (1993) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Marc A. Taubenblatt, Marc A. Taubenblatt, John Samuel Batchelder, John Samuel Batchelder, "Detection and refractive index identification of submicron particles on surfaces", Proc. SPIE 1821, Industrial Applications of Optical Inspection, Metrology, and Sensing, (28 May 1993); doi: 10.1117/12.145532; https://doi.org/10.1117/12.145532
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