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Segregation of Cu on Etched and Non-Etched Al(Cu) Surface

Published online by Cambridge University Press:  10 February 2011

Hua Li ,
Karen Maex ,
Bert Brijs ,
Thierry Conard ,
Wilfried Vandervorst ,
Michael Baklanov ,
Werner Boullart  and
Ludo Froyen
Hua Li
Affiliation:
IMEC, Kapeldreef 75, 3001 Leuven, Belgium
Karen Maex
Affiliation:
IMEC, Kapeldreef 75, 3001 Leuven, Belgium
Bert Brijs
Affiliation:
IMEC, Kapeldreef 75, 3001 Leuven, Belgium
Thierry Conard
Affiliation:
IMEC, Kapeldreef 75, 3001 Leuven, Belgium
Wilfried Vandervorst
Affiliation:
IMEC, Kapeldreef 75, 3001 Leuven, Belgium
Michael Baklanov
Affiliation:
IMEC, Kapeldreef 75, 3001 Leuven, Belgium
Werner Boullart
Affiliation:
IMEC, Kapeldreef 75, 3001 Leuven, Belgium
Ludo Froyen
Affiliation:
Dept.of Metallurgy and Materials Engineering, K.U. Leuven, 3001 Leuven, Belgium
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Abstract

In this paper, we have studied the segregation phenomenon of Cu on the surfaces of patterned lines, dry-etched films and non-etched films, by using X-ray photoelectron spectroscopy and lower energy Rutherford Backscattering Spectrometry. Significant enrichment of Cu is found on the sidewall of the lines. Annealing at 350°C and above cause the disappearance of this enrichment. Origin and evolution of this Cu enrichment have been investigated on films taken out from different steps of the etching process. It has been found that most of the Cu products induced by the plasma etching are CuCl and CuCl2 and they are removed mostly from the top Al oxide layer by the strip process. On the interface area between Al and the native oxide, considerable quantities of etched induced Cu are retained. This Cu is identified to be mainly metallic Cu. Different from the mechanism explained above, thermal annealing can also cause Cu segregation. We have found that Cu atoms diffuse into the native Al oxide where they form Cu2O.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 516: Symposium E – Low Dielectric Constant Materials IV , January 1998 , 77
Copyright
Copyright © Materials Research Society 1998

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