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A New Cleaning Technique for Corrosion Protection in Aluminum Metallization

Published online by Cambridge University Press:  01 February 2011

Masako Kodera ,
Shin-ichiro Uekusa ,
Yoshitaka Matsui ,
Naoto Miyashita ,
Atsushi Shigeta ,
Shinya Takahashi ,
Murato Kawai ,
Hiroshi Kawamoto  and
Manabu Tsujimura
Masako Kodera
Affiliation:
Toshiba Corporation, Yokohama, Japan Meiji University, Kawasaki, Japan
Shin-ichiro Uekusa
Affiliation:
Meiji University, Kawasaki, Japan
Yoshitaka Matsui
Affiliation:
Toshiba Corporation, Yokohama, Japan
Naoto Miyashita
Affiliation:
Toshiba Corporation, Yokohama, Japan Meiji University, Kawasaki, Japan
Atsushi Shigeta
Affiliation:
Toshiba Corporation, Yokohama, Japan
Shinya Takahashi
Affiliation:
Toshiba Corporation, Yokohama, Japan
Murato Kawai
Affiliation:
Toshiba Corporation, Yokohama, Japan
Hiroshi Kawamoto
Affiliation:
Toshiba Corporation, Yokohama, Japan
Manabu Tsujimura
Affiliation:
Ebara Corporation, Fujisawa, Japan
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Abstract

A new cleaning technique using gas dissolved water has been found to be effective in protecting against corrosion in aluminum metallization, which is also useful in post-cleaning of Cu CMP as already reported. Corrosion can be a significant concern in aluminum as well as in copper metallization. In Al CMP process, corrosion often occurs in contact with DIWbecause of the big potential difference between Al and the barrier metal. In this study, it has been confirmed that gas dissolved water is able to change the potential of various metal films, and that following Al CMP, post-cleaning using gas dissolved water instead of DIW can successfully protect against corrosion.

Furthermore this technique is also effective in the post-cleaning process of Al wiring formed by RIE, which contains a slight amount of Cu. Because segregation of copper at the side-wall of wiring often occurs during RIE and the following processes, Al-Cu wiring is easily corroded during the DIW rinsing step in wet cleaning, which may cause killer defects. Gas dissolved water can remarkably decrease the potential difference between Al-Cu alloy and segregated Cu, as well as Al-Cu alloy and the Ti/TiN used as a barrier metal. Moreover, because it seems that a reaction occurs between cathode water and Ti/TiN, where electrons may be supplied there to corrosive sites, corrosion can be prevented.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 767: Symposium F – Chemical-Mechanical Planarization , 2003 , F7.2
Copyright
Copyright © Materials Research Society 2003

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References

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