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Copper CMP for Dual Damascene Technology: Some Considerations on the Mechanism of Cu Removal

  • David Wei (a1), Yehiel Gotkis (a1), Hugh Li (a1), Stephen Jew (a1), Joseph Li (a1), Sri Srivatsan (a1), Joseph Simon (a1), John M. Boyd (a1), KY Ramanujam (a1) and Rodney Kistler (a1)...

Abstract

It was found in a Cu-CMP process using EP-C 5001 slurry and IC 1000 pad that Cu removal rate, being extremely low without H2O2 in the slurry, increases up to a maximum with the addition of H2O2, and then decreases again. Analysis of polarization curves and Eh-pH diagrams shows that without H2O2 Cu has the lowest electric potential, as a result, the highest thermodynamic stability in the Cu/slurry system. Addition of H2O2 shifts the potential up and induces the formation of Cu2O, resulting in a high removal rate. At high H2O2 concentration, a CuO passivation film is formed. In this case, only mechanical removal of the passivating oxide film allows the process to proceed. It is speculated that the moving pad surface adheres the oxidized species via the formation of hydrogen bonds with oxygen atoms of copper oxide molecules, thus detaching them from the wafer surface. Each oxygen atom is capable of pulling out two Cu atoms if Cu2O is formed on the surface and only one Cu atom if CuO is formed. This would explain why the removal rate is high at low H2O2 concentration and low at high H2O2 concentration.

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1. Gotkis, Y. and Kistler, R., in Fundamentals of Cu CMP for Dual Damascene Technology, 2000 VMIC Proceedings, VG, p.200 (2000).
2. Zeidler, D., Stavreva, Z., Plötner, M., Drescher, K.. Characterization of Cu chemical mechanical polishing by electrochemical investigations. Microelectronic Engineering 33 p.259 (1997).10.1016/S0167-9317(96)00053-6
3. Ritzdorf, T., Graham, L., Lin, S., Mu, C., and Fraser, D., in Proceedings of the 1998 IEEE International Interconnect Conference, 166 (1998).
4. Li, Y., Hariharaputhiran, M., Babu, S.V.. Chemical-mechanical polishing of copper and tantalum with silica abrasives. J. Mater. Res., Vol. 16, No 4, Apr 2001.
5. Lee, H., Lopatin, S. D., and Wang, S. S., in Proceedings of the 2000 IITC International Interconnect Technology Conference, SF, California, p.114 (2000).
6. Pourbaix, M., in Atlas of Electrochemical Equilibria in Aqueous Solutions, p.384, Pergamon Press, New York (1966).

Copper CMP for Dual Damascene Technology: Some Considerations on the Mechanism of Cu Removal

  • David Wei (a1), Yehiel Gotkis (a1), Hugh Li (a1), Stephen Jew (a1), Joseph Li (a1), Sri Srivatsan (a1), Joseph Simon (a1), John M. Boyd (a1), KY Ramanujam (a1) and Rodney Kistler (a1)...

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