Hostname: page-component-586b7cd67f-l7hp2 Total loading time: 0 Render date: 2024-11-25T01:42:31.087Z Has data issue: false hasContentIssue false
  • English
  • Français

Influence of Ionic Strength and pH-value on the Silicon Dioxide Polishing Behaviour of Slurries Based on Pure Silica Suspensions

Published online by Cambridge University Press:  01 February 2011

Ulrich Kuenzelmann ,
Kathrin Estel ,
Johann W Bartha ,
Erwin-Peter Meyer  and
Herbert Barthel
Ulrich Kuenzelmann
Affiliation:
[email protected]
Kathrin Estel
Affiliation:
[email protected], Dresden University of Technology, Institute of Semiconductors and Microsystem Technology, Dresden, Germany
Johann W Bartha
Affiliation:
[email protected], United States
Erwin-Peter Meyer
Affiliation:
[email protected], Wacker Chemie AG, München, Germany
Herbert Barthel
Affiliation:
[email protected], Wacker Chemie AG, München, Germany
Get access

Abstract

In this study, the effect of the addition of electrolytes in a given ionic strength to various high-purity silica suspensions was investigated by measurement of the removal rates (RR's) in CMP processes on oxide layers under the same experimental conditions. As so-called slurries the following suspensions were used: i) silica sols produced by the Stöber process, ii) conventional silica sols based on alkali silicate as well as iii) suspensions of fumed silica, with the same SiO2 concentration in each suspension. Ionic strength of the added electrolyte was adjusted to e.g. 0.065 mol/l, with the electrolytes being HCl, NH4Cl, KOH, or binary mixtures of these substances.

These investigations revealed significant differences of the polishing behaviour between the different types of silica dispersions as slurries. While for the Stöber sols investigated, the RR's are highest in the acidic range and almost negligible in the alkaline pH range, fumed silica suspensions show an entirely different behaviour: RR is very low for acidic pH-values, and increases with the alkalinity of the slurry. In contrast to these observations, the RR's of slurries based on conventional silica sols are highest around the neutral point, and show a decrease for both more alkaline and acidic pH-values. In comparison to the other two types of material, these suspensions have a high amount of electrolyte background, originating from their manufacturing process.

A model is developed to explain these results in a comprehensive manner. It involves effects of the electrolyte type and the ionic strengths as well as influences of the particle size.

Keywords

CMPcolloidslurry
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1249: Symposia E/F – Advanced Interconnects and Chemical Mechanical Planarization for Micro-and Nanoelectronics , 2010 , 1249-E04-02
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 Steigerwald, J. M. Murarka, S. P. and Gutmann, R. J. Chemical Mechanical Planarization of Microelectronic Materials (John Wiley & Sons, New York, 1997)Google Scholar
2 Singh, R. K. and Bajaj, R. in Advances in Chemical-Mechanical-Planarization 2002, eds. Singh, R. K. and Bajaj, R. (Materials Research Society Bulletin PV 27-10, Warrendale, PA, 2002), p. 743 Google Scholar
3 Preston, F. J. Soc. Glass Tech. 11, 214, (1927)Google Scholar
4 Cook, L.M. J. Non-Cryst. Solids 120, 152 (1990).Google Scholar
5 Matijeviæ, E., and Babu, S.V. J. Colloid Interface Sci. 320, 219 (2008).Google Scholar
6 Choi, W. Lee, S.M. and Singh, R. K. Electrochem. and Solid-State Lett., 7 G141, (2004).Google Scholar
7 Choi, W. Mahajan, U. Lee, S.M. Abiade, Jeremiah, and Singh, R. K. J. Electrochem. Soc. 151 G185, (2004).Google Scholar
8 Choi, W. Abiade, Jeremiah, Lee, S.M. and Singh, R. K. J. Electrochem. Soc. 151 G512, (2004).Google Scholar
9 Hayashi, Y. Sakurai, M. Nakajima, T. and Hayashi, K. Jpn. J. Appl. Phys., Part 1 34, 1037 (1995).Google Scholar
10 Stöber, W., Fink, A. Bohn, E. J. Colloid Interface Sci. 26, 62, (1968).Google Scholar
11 Iler, R.K. The Chemistry of Silica (Wiley–Interscience, New York, 1979).Google Scholar
12 Kosmulski, M. Hartikainen, J. Maczka, E. Janusz, W. and Rosenholm, J.B. Anal. Chem. 74, 253, (2002).Google Scholar
13 Derjaguin, B.V., Trans. Faraday Soc. 36, 730, (1940).Google Scholar
14 Verwey, E.J.W., Overbeek, J.T.G., Theory of the Stability of Lyophobic Colloids (Elsevier, Amsterdam, 1948).Google Scholar
15 Lagaly, G. Dispersionen und Emulsionen (Steinkopff, Darmstadt, 1997).Google Scholar