Hostname: page-component-78c5997874-fbnjt Total loading time: 0 Render date: 2024-11-13T03:07:56.794Z Has data issue: false hasContentIssue false

Mechanistic Investigations of Ruthenium Polishing Enabled by Heterogeneous Catalysis With Titania-based Slurries

Published online by Cambridge University Press:  01 February 2011

Daniela White
Affiliation:
Daniela_White@cabotcmp.com, Cabot Microelectronics, Aurora, United States
John C Parker
Affiliation:
John_Parker@cabotcmp.com, Cabot Microelectronics, Aurora, United States
R Nagarajan
Affiliation:
R_Nagarajan@cabotcmp.com, Cabot Microelectronics, Aurora, United States
Get access

Abstract

Difficulties and challenges have been widely encountered in the chemical mechanical planarization (CMP) of noble metals used as diffusion barrier films due to hardness, chemical inertness and toxic oxidation products, in particular for Ru polishing. A commercial CMC Ru polishing slurry that successfully addressed the safety concerns was based on a high pH (8.4) polymer-treated-alumina-based multi-additive slurry containing complexing reagents (carboxylic acids and salts), corrosion inhibitors, surfactants, and hydrogen peroxide as a mild, non-aggressive oxidizer. Recently, our efforts had been redirected towards the development of a new generation of low pH barrier slurries based on an entirely new concept employing unique Lewis acid type abrasives. This class of materials is well known to be highly reactive in dielectrics polishing (ceria, zirconia, titania), but far less is known about their interactions with Ru, Cu or Ta.

In this presentation, we will elaborate the unexpected discovery that hard, chemically inert, noble metals such as ruthenium can be polished easily by virtually abrasive-free and/or oxidizer-free TiO2 based slurries. Of particular importance is the finding that the polymorphic phase of TiO2 (anatase or rutile), its surface chemistry (functional groups, Lewis acid/base character), pH induced surface modification and reactivity, can all mediate the abrasive particle's adsorption properties, catalytic activity and ultimately, its slurry polishing performance.

Type
Research Article
Copyright
Copyright © Materials Research Society 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1 Chyan, O. Arungini, T. N. J. Electrochem. Soc. 150, C347 (2003)Google Scholar
2 Cho, S. K. Kim, S. K. Han, H. J. Vac. Sci. Technol. B22 (6), 2649 (2004)Google Scholar
3 Smoluchowski, M. Von, Z. Phys. Chem. 92, 129 (1917)Google Scholar
4 Pugh, R. J. Ceramic Powder Science III, 375 (1991)Google Scholar
5 Giamello, E. Volante, M. Fubini, B. Geobaldo, F. Morterra, C. Materials Chemistry & Physics 29, 379 (1991)Google Scholar
6 Boonstra, A. H. Mutsaers, C. A. H. J. Phys. Chem. 79, 1940 (1975)Google Scholar
7 Hiroki, A. LaVerne, J. A. J. Phys. Chem. B109, 3364 (2005)Google Scholar
8 Zhang, L. Cosandey, F. Persaud, P. Surf. Sci. 439, 73 (1999)Google Scholar
9 Chudek, J. A. McQuire, M. W. McQuire, G. W. Rochester, C. J. Chem. Soc., Faraday Trans. 90, 3699 (1994)Google Scholar
10 Roginskaya, Yu. E. Materials Chemistry and Physics, 22, 203 (1989)Google Scholar