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Journal of Micro/Nanolithography, MEMS, and MOEMS

Optical critical dimension measurement of silicon grating targets using back focal plane scatterfield microscopy
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Paper Abstract

We demonstrate optical critical dimension measurement of lines in silicon grating targets using back focal plane scatterfield icroscopy. In this technique, angle-resolved diffraction signatures are obtained from grating targets by imaging the back focal plane of a brightfield microscope that has been modified to allow selection of the angular distribution and polarization of the incident illumination. The target line profiles, including critical dimension linewidth and sidewall angle, are extracted using a scatterometry method that compares the diffraction signatures to a library of theoretical signatures. Because we use the zero-order component of the diffraction, the target features need not be resolved in order to obtain the line profile. We extracted line profiles from two series of targets with fixed pitch but varying linewidth: a subresolution 300-nm-pitch series, and a resolved 600-nm-pitch series. Linewidths of 131 nm to 139 nm were obtained, with nanometer-level sensitivity to linewidth, and a linear relationship of linewidth obtained from scatterfield microscopy to linewidth measured by scanning electron microscopy was demonstrated. Conventional images can be easily collected on the same microscope, providing a powerful tool for combining imaging metrology with scatterometry for optical critical dimension measurement.

Paper Details

Date Published: 1 January 2008
PDF: 11 pages
J. Micro/Nanolith. 7(1) 013012 doi: 10.1117/1.2885275
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 7, Issue 1
Show Author Affiliations
Heather J. Patrick, National Institute of Standards and Technology (United States)
Ravikiran Attota, National Institute of Standards and Technology (United States)
Bryan M. Barnes, National Institute of Standards and Technology (United States)
Thomas A. Germer, National Institute of Standards and Technology (United States)
Ronald G. Dixson, National Institute of Standards and Technology (United States)
Michael D. Stocker, National Institute of Standards and Technology (United States)
Richard M. Silver, National Institute of Standards and Technology (United States)
Michael R. Bishop, International SEMATECH Manufacturing Initiative (United States)


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