Resistivity Dominated by Surface Scattering in Sub-50 nm Cu Wires

Published

January 25, 2010

Author(s)

Rebekah L. Graham, Glenn Alers, Thomas Mountsier, N. Shamma, S. Dhuey, R. H. Cabrini, Roy H. Geiss, David T. Read, S. Peddeti

Abstract

The electron scattering mechanisms in sub-50nm copper lines were investigated to understand the extendibility of copper interconnects when the line width or thickness is less than the mean free path. Electron-beam lithography and a dual hardmask approach were used to produce interconnects with line widths between 25 and 45 nm. Grain structure was characterized with electron backscatter diffraction, which demonstrated that grains are much longer than the width of wire cross sections. Resistivity was determined from the temperature dependence of the line resistance and was consistent with existing models for completely diffuse surface scattering, with little contribution from grain boundary scattering. A simple analytical model is developed that accurately describes resistivity from diffuse surface scattering in three dimensions.

Citation

Applied Physics Letters

Volume

96

Issue

4

Pub Type

Journals

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DOI Link

Keywords

Copper, damascene, electrical resistance, grain size, linewidth, mean free path, surface scattering

Citation

Graham, R. , Alers, G. , Mountsier, T. , Shamma, N. , Dhuey, S. , Cabrini, R. , Geiss, R. , Read, D. and Peddeti, S. (2010), Resistivity Dominated by Surface Scattering in Sub-50 nm Cu Wires, Applied Physics Letters, [online], https://doi.org/10.1063/1.3292022 (Accessed October 16, 2025)