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Line Width Roughness and Cross Sectional Measurements of Sub-50 nm Structures with CD-SAXS and CD-SEM



Chengqing C. Wang, Ronald L. Jones, Kwang-Woo Choi, Christopher L. Soles, Eric K. Lin, Wen-Li Wu, James S. Clarke, John S. Villarrubia, Benjamin Bunday


Critical dimension small angle x-ray scattering (CD-SAXS) is a measurement platform which is capable of measuring the average cross section and sidewall roughness in patterns ranging from (10 to 500) nm in pitch with sub nm precision. These capabilities are obtained by measuring and modeling the scattering intensities of a collimated x-ray beam with sub-Angstrom wavelength from a periodic pattern, such as those found in optical scatterometry targets. In this work, we evaluate the capability of both a laboratory scale and synchrotron based CD-SAXS measurements for line-width roughness (LWR) characterization from measurement of periodic line-space patterns fabricated with EUV lithography with sub-50 nm line widths and designed with programmed roughness amplitude and frequency. For these patterns, CD-SAXS is capable of providing high precision data on cross section dimensions, including sidewall angle, line height, line width and pitch, as well as the LWR amplitude. We also discuss the status of ongoing efforts to compare quantitatively the CD-SAXS data with top-down scanning electron microscopy (CD-SEM) measurements.
SPIE Conference Proceedings


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


Wang, C. , Jones, R. , Choi, K. , Soles, C. , Lin, E. , Wu, W. , Clarke, J. , Villarrubia, J. and Bunday, B. (2008), Line Width Roughness and Cross Sectional Measurements of Sub-50 nm Structures with CD-SAXS and CD-SEM, SPIE Conference Proceedings, [online], (Accessed April 21, 2024)
Created March 24, 2008, Updated February 19, 2017