Ellipsometry in the EUV Regime

Published

April 24, 2025

Author(s)

Aaron Chew, Bryan Barnes, Eric Shirley, Thomas Germer

Abstract

We propose and analyze the sensitivity of an ellipsometer that uses extreme ultraviolet (EUV) light from the synchrotron SURF-III. The ellipsometer employs a four-mirror geometry to control polarization, as documented in the associated patent. With a combination of Monte Carlo simulations and least squares fitting, we examine the benefits of both employing shorter wavelengths and polarization control as a measurement tool for several industrially relevant geometries, and observe the parametric decorrelation of important fitting parameters. This decorrelation is explained with simplified models. We find that the shorter wavelength of EUV light yields clear benefits for scatterometry experiments, and polarization control offers a new degree of freedom control that can be extremely beneficial when other degrees of freedom, such as wavelength control or angle of incidence, are inaccessible or unable to decorrelate parameters.

Proceedings Title

Metrology, Inspection, Process Control, xxxix

Volume

13426

Conference Dates

February 23-27, 2025

Conference Location

San Jose, CA, US

Conference Title

SPIE Advanced Lithography and Patterning

Pub Type

Conferences

Download Paper

https://doi.org/10.1117/12.3053165

Local Download

Keywords

diffractometry, ellipsometry, EUV, maximum likelihood estimation, Monte Carlo, nanofork, nanosheet, RCWA, sensitivity, ultraviolet

Citation

Chew, A. , Barnes, B. , Shirley, E. and Germer, T. (2025), Ellipsometry in the EUV Regime, Metrology, Inspection, Process Control, xxxix, San Jose, CA, US, [online], https://doi.org/10.1117/12.3053165, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=959589 (Accessed October 1, 2025)