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EBSD Analysis of Narrow Damascene Copper Lines

Published

Author(s)

Roy H. Geiss, David T. Read, Glenn Alers, Rebekah L. Graham

Abstract

Orientation imaging microscopy (OIM) by electron back scatter diffraction (EBSD) has been used to examine grain size and crystallographic orientations of damascene Cu lines nominally 25 nm to 55 nm in width and 100 nm thick. These are the smallest structures reported to have been examined by EBSD to date; this application poses significant challenges in specimen preparation, data collection, and data analysis. Most lines were deposited on a Ta diffusion barrier, but one set had a Ti barrier. Overburden thicknesses of 120 nm, 240nm, and 480 nm were available with the Ta diffusion barrier, but only the 120 nm overburden case was analyzed for the Ti diffusion barrier. The grain structure of the lines was predominantly bamboo, with one grain filling the whole line width. The distributions of grain lengths along individual lines had large standard deviations, ranging up to greater than the average grain size value. Print-through of overburden grains into the grain structure of the lines was evident for all lines. Large grain sizes and a strong positive correlation between line width and grain size were seen for the case of the Ta barrier layer and 120 nm overburden thickness, but not for the thicker overburden cases. Specimen surface preparation of these lines was found to be much more demanding than for larger regions of copper film such as have been studied previously; for some lines, prepared according to the typical state of the art, we were able to find indexable diffraction signals from less than half of the line length.
Proceedings Title
Proceedings of Frontiers of Characterization and Metrology for Nanoelectronics
Volume
1173
Conference Dates
May 11-15, 2009
Conference Location
Albany, NY, US
Conference Title
Frontiers of Characterization and Metrology for Nanoelectronics

Keywords

grain, microstructure, overburden, print-through, texture

Citation

Geiss, R. , Read, D. , Alers, G. and Graham, R. (2009), EBSD Analysis of Narrow Damascene Copper Lines, Proceedings of Frontiers of Characterization and Metrology for Nanoelectronics, Albany, NY, US, [online], https://doi.org/10.1063/1.3251212 (Accessed March 5, 2024)
Created May 10, 2009, Updated October 12, 2021