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Towards High Accuracy Reflectometry for Extreme-Ultraviolet Lithography



Charles S. Tarrio, S Grantham, M B. Squires, Robert E. Vest, Thomas B. Lucatorto


Currently the most demanding application of extreme ultraviolet optics is connected with the development of extreme ultraviolet lithography. Not only does each of the Mo/Si multilayer EUV stepper mirrors require the highest attainable reflectivity at 13 nm (nearly 70%), but the central wavelength of the reflectivity of these mirrors must be measured to a precision of 0.001 nm and peak reflectivity of the reflective masks to a precision of 0.12%. We report on two upgrades of our NIST/DARPA Reflectometry Facility that have given us the ability to achieve 0.1% precision and 0.3% absolute accuracy in our reflectivity measurements. A third upgrade, a monochromator with thermal and mechanical stability for improved wavelength precision, is currently in the design phase.
Journal of Research (NIST JRES) -
108 No. 4


extreme ultraviolet, lithography, metrology, reflectometry, synchrotron radiation


Tarrio, C. , Grantham, S. , Squires, M. , Vest, R. and Lucatorto, T. (2003), Towards High Accuracy Reflectometry for Extreme-Ultraviolet Lithography, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD (Accessed April 24, 2024)
Created July 1, 2003, Updated February 17, 2017