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The Effect of Grain Boundaries on Surface Diffusion Mediated-Planarization of Polycrystalline Cu Films

Published online by Cambridge University Press:  15 February 2011

R.A. Brain
Affiliation:
Thomas J. Watson Laboratory of Applied Physics California Institute of Technology, Pasadena, CA 91125.
D.S. Gardner
Affiliation:
Components Research, Intel Corporation, Santa Clara, CA 95052.
D.B. Fraser
Affiliation:
Components Research, Intel Corporation, Santa Clara, CA 95052.
H.A. Atwater
Affiliation:
Thomas J. Watson Laboratory of Applied Physics California Institute of Technology, Pasadena, CA 91125.
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Abstract

In situ, ultrahigh vacuum anneals were performed to induce Cu reflow at 500°C following deposition of Cu films and a Ta barrier layer on 1 μm wide by 1 μm deep trenches. Transmission electron micrograph cross-sections show profiles which suggest that grain boundaries and surface energy anisotropy significantly affect reflow. The extent of reflow is dependent on the structure of grain boundary-surface intersections, and the surface profile consists of regions of low curvature within grains and with sharp discontinuities in curvature at grain boundaries, a structure that inhibits surface diffusion. We present results showing how the surface diffusion mediated reflow varies with grain boundary groove angle and position, and compare these results with finite-element simulations that model surface diffusion-driven reflow.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

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References

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