NIST - National Institute of Standards and Technology
04/24/2025 | Press release | Archived content
Lab-based multi-wavelength EUV diffractometry for critical dimension metrology
Published
April 24, 2025
Author(s)
Bryan Barnes, Aaron Chew, Nicholas Jenkins, Yunzhe Shao, Martin Sohn, Regis Kline, Daniel Sunday, Purnima Balakrishnan, Thomas Germer, Steven Grantham, Clay Klein, Stephanie Moffitt, Eric Shirley, Henry Kapteyn, MARGARET MURNANE
Abstract
Background: The industry is developing extreme-ultraviolet wavelength (EUV) techniques to measure critical dimensions (CDs) in logic fabrication. As nascent approaches are unveiled, evaluations against reference metrologies are essential to motivate development at higher speeds using industrially relevant length scales. Aim: The parametric geometries determined from EUV diffractometry data using a tabletop coherent highharmonic generation (HHG) source are compared against dimensions from synchrotron-based CD small angle x-ray scattering (CD-SAXS) for four line-space arrays with CDs below 50 nm. Approach: An EUV imaging reflectometer captures the 0th order reflection and the 1st order diffraction intensities as functions of grazing angle. The 1st order intensities are functions of five wavelengths from the spectral comb of this HHG source. Fits to these data using rigorous couple-wave analysis (RCWA) electromagnetic simulations yield parametric values and uncertainties. Results: EUV diffractometry simulations match well in general with the measured data after accounting for cross-sectional geometry and experimental conditions. EUV diffractometry line widths correlate well against those of CD-SAXS at the mid-height of the latter. Conclusions: These promising results were obtained using a general-purpose prototype coherent EUV reflectometer. Routes for further enhancing the sensitivity and accuracy are presented and are in progress.
Proceedings Title
Metrology, Inspection, and Process Control XXXIX
Volume
13426
Conference Dates
February 24-27, 2025
Conference Location
San Jose, CA, US
Conference Title
SPIE Advanced Lithography + Patterning
Pub Type
Conferences
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Citation
Barnes, B. , Chew, A. , Jenkins, N. , Shao, Y. , Sohn, M. , Kline, R. , Sunday, D. , Balakrishnan, P. , Germer, T. , Grantham, S. , Klein, C. , Moffitt, S. , Shirley, E. , Kapteyn, H. and Murnane, M. (2025), Lab-based multi-wavelength EUV diffractometry for critical dimension metrology, Metrology, Inspection, and Process Control XXXIX, San Jose, CA, US, [online], https://doi.org/10.1117/12.3050342, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=959709 (Accessed April 29, 2025)
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