Comparison of SEM and AFM performances for LER reference metrology

Ryosuke Kizu; Ichiko Misumi; Akiko Hirai; Satoshi Gonda

doi:10.1117/12.2551468

20 March 2020 Comparison of SEM and AFM performances for LER reference metrology

Ryosuke Kizu, Ichiko Misumi, Akiko Hirai, Satoshi Gonda

Proceedings Volume 11325, Metrology, Inspection, and Process Control for Microlithography XXXIV; 113250Q (2020) https://doi.org/10.1117/12.2551468
Event: SPIE Advanced Lithography, 2020, San Jose, California, United States

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.

Conference Presentation

Citation Download Citation

Ryosuke Kizu, Ichiko Misumi, Akiko Hirai, and Satoshi Gonda "Comparison of SEM and AFM performances for LER reference metrology", Proc. SPIE 11325, Metrology, Inspection, and Process Control for Microlithography XXXIV, 113250Q (20 March 2020); https://doi.org/10.1117/12.2551468

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