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Proceedings Paper

Comparison of SEM and AFM performances for LER reference metrology
Author(s): Ryosuke Kizu; Ichiko Misumi; Akiko Hirai; Satoshi Gonda
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Paper Abstract

Line edge roughness (LER) measurement of a nanoscale line pattern is a metrology challenge in the inspection of semiconductor devices. Conventional scanning electron microscopy (SEM), a classical LER measurement technique, is a top-view (2D) metrology and incapable of accurately measuring 3D structures. For LER measurements, SEM measurement generates a single line edge profile for the 3D sidewall roughness, although the line edge profile differs at each height in the 3D sidewall. In this study, we used atomic force microscopy (AFM) with the tip-tilting technique to measure the 3D sidewall roughness, as an LER reference metrology. An identical location of a line pattern measured by SEM and AFM was compared to evaluate the SEM’s performance. The line edge profile from the AFM measurement exhibited lower noise than that from SEM. The measured line edge profiles were analyzed using the power spectral density (PSD), height-height correlation function (HHCF), and autocorrelation function. The results demonstrate that the standard deviation (σ) and correlation length (ξ) are overestimated while the roughness exponent (α) is underestimated by SEM, considering the AFM results as reference values.

Paper Details

Date Published: 20 March 2020
PDF: 8 pages
Proc. SPIE 11325, Metrology, Inspection, and Process Control for Microlithography XXXIV, 113250Q (20 March 2020); doi: 10.1117/12.2551468
Show Author Affiliations
Ryosuke Kizu, National Institute of Advanced Industrial Science and Technology (Japan)
Ichiko Misumi, National Institute of Advanced Industrial Science and Technology (Japan)
Akiko Hirai, National Institute of Advanced Industrial Science and Technology (Japan)
Satoshi Gonda, National Institute of Advanced Industrial Science and Technology (Japan)


Published in SPIE Proceedings Vol. 11325:
Metrology, Inspection, and Process Control for Microlithography XXXIV
Ofer Adan; John C. Robinson, Editor(s)

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