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Accurate Size Measurement of Monosize Calibration Spheres by Differential Mobility Analysis.


pdf icon Accurate Size Measurement of Monosize Calibration Spheres by Differential Mobility Analysis. (555 K)
Mulholland, G. W.; Fernandez, M. G.

Characterization and Metrology for ULSI Technology. International Conference, 1998. CP449. Proceedings. March 1998, Gaithersburg, MD, American Institute of Physics, Seiler, D. G.; Diebold, A. C.; Bullis, W. M.; Shaffner, T. J., Editor(s)(s), 819-823 pp, 1998.

Keywords:

mobility; particle size; polystyrene

Abstract:

A differential mobility analyzer was used to measure the mean particle size of three monosize suspensions of polystyrene spheres in water. Key features of the experiment to minimize the uncertainty in the results include developing a recirculating flow to ensure equal flows into and out of the classifier, an accurate divider circuit for calibrating the electrode voltage, and use of the 100.7 nm NIST SRM for calibrating the flow of the classifier. The measured average sizes and expanded uncertainties with a coverage factor of 2 are 92.4 mn + 1.1 nm, 126.9 nm + 1.4 nm, and 217.7 nm + 3.4 nm. These calibration sizes were characterized by NIST to improve the calibration of scanning surface inspection systems.