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Silicon Wafer Thickness Variation Measurements Using the NIST Infrared Interferometer

Published

Author(s)

Angela Davies, Tony L. Schmitz, R E. Parks, Christopher J. Evans

Abstract

?creasing depths of focus, coupled with increasing silicon wafer diameters, place greater restrictions on chucked wafer flatness in photolithography processes. In this work, a measurement device is described that measures thickness variation of double side polished wafers using an infrared source and vidicon detector. Various possible instrument configurations are described with the focus on a setup which uses a collimated wavefront to produce interference fringes between the front and back surfaces of the plane parallel wafer. Experimental results are presented, including a drift test; comparisons between measurements performed using different collimators and, subsequently, wavefronts; an exploration of the impact of phase change on reflection due to the clamping method; and an intercomparison with thickness measurements recorded by a capacitance gage-based instrument and surface measurements obtained using a separate visible wavelength interferometer.
Citation
Optical Engineering
Volume
42 (8)

Keywords

interferometry, photolithography, silicon wafer, thickness variation

Citation

Davies, A. , Schmitz, T. , Parks, R. and Evans, C. (2003), Silicon Wafer Thickness Variation Measurements Using the NIST Infrared Interferometer, Optical Engineering (Accessed June 22, 2024)

Issues

If you have any questions about this publication or are having problems accessing it, please contact reflib@nist.gov.

Created August 1, 2003, Updated February 19, 2017