Presentation + Paper
20 June 2021 Fast and robust diffraction based overlay metrology using dark-field digital holographic microscopy
T. T. M. van Schaijk, C. Messinis, N. Pandey, V. T. Tenner, A. Koolen, S. Witte, J. F. de Boer, A. J. den Boef
Author Affiliations +
Abstract
Digital holographic microscopy allows access to the complex electric field, enabling computational propagation of light. This enables computational corrections for lens aberrations, which remove the requirement for antireflective coatings on the lens and enable imaging over a wide spectral range. This makes digital holographic microscopy an interesting candidate for overlay metrology on semiconductor wafers. We show that a single holographic image contains all data that is required for computing the overlay, by using a source with a limited coherence length and incoherently adding multiple measurements on a camera. As an additional benefit we show that such parallel acquisition improves the reproducibility of the experiment by eliminating noise sources that are common to the two measurements that typically constitute a single overlay measurement.
Conference Presentation
© (2021) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
T. T. M. van Schaijk, C. Messinis, N. Pandey, V. T. Tenner, A. Koolen, S. Witte, J. F. de Boer, and A. J. den Boef "Fast and robust diffraction based overlay metrology using dark-field digital holographic microscopy", Proc. SPIE 11782, Optical Measurement Systems for Industrial Inspection XII, 117820O (20 June 2021); https://doi.org/10.1117/12.2591989
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KEYWORDS
Overlay metrology

Digital holography

Diffraction

Microscopy

Diffraction gratings

Holography

Metrology

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