Line Edge Roughness Characterization of Sub-50nm Structures Using CD-SAXS: Round-Robin Benchmark Results

Published

January 1, 2007

Author(s)

Chengqing C. Wang, J C. Roberts, Robert Bristol, B Bunday, Ronald L. Jones, Eric K. Lin, Wen-Li Wu, John S. Villarrubia, Kwang-Woo Choi, James S. Clarke, Bryan J. Rice, Michael Leeson

Abstract

he need to characterize line edge and line width roughness in patterns with sub-50 nm critical dimension challenges existing platforms based on electron microscopy and optical scatterometry. The development of x-ray based metrology platforms provides a potential route to characterize a variety of parameters related to line edge roughness by analyzing the diffracted intensity from a periodic array of test patterns. In this study, data from a series of photoresist line/space patterns featuring programmed line width roughness measured by critical dimension small angle x-ray scattering (CD-SAXS) is presented. For samples with periodic roughness, CD-SAXS provides the wavelength and amplitude of the periodic roughness through satellite diffraction peaks. In addition, the rate of decay of intensity, termed an effective Debye-Waller factor, as a function of scattering vector provides a measure of the fluctuation in line volume.CD-SAXS data are compared to analogous values obtained from CD-SEM. Correlations between the techniques exist, however significant differences are observed for the current samples. C-AFM data reveal large fluctuations in both line height and line width, providing a potential explanation for the observed disparity between CD-SEM and CD-SAXS.

Citation

SPIE

Volume

263

Pub Type

Journals

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Keywords

line edge roughness, scatterometry, small angle x-ray scattering

Citation

Wang, C. , Roberts, J. , Bristol, R. , Bunday, B. , Jones, R. , Lin, E. , Wu, W. , Villarrubia, J. , Choi, K. , Clarke, J. , Rice, B. and Leeson, M. (2007), Line Edge Roughness Characterization of Sub-50nm Structures Using CD-SAXS: Round-Robin Benchmark Results, SPIE, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852720 (Accessed October 10, 2025)