Hostname: page-component-586b7cd67f-vdxz6 Total loading time: 0 Render date: 2024-11-29T07:24:18.416Z Has data issue: false hasContentIssue false

Cerium Oxide Abrasives – Observations and Analysis

Published online by Cambridge University Press:  15 March 2011

David R. Evans*
Affiliation:
SHARP Laboratories of America, Inc. Camas, WA 98607, USA
Get access

Abstract

The use of cerium oxide (ceria) as an abrasive for dielectric chemical mechanical polishing has a “checkered” history to say the least. Nevertheless, its use remains attractive for this purpose because of favorable polishing characteristics that are generally not obtainable using conventional fumed or colloidal silica abrasives. To be specific, large differences are commonly observed between removal rates of thin film silicon oxide, silicon nitride, and/or polysilicon. Moreover, such rate selectivity invariably favors removal of oxide films, which of course, is precisely what is desirable for fabrication of modern shallow trench isolation schemes. Even so, CMP using ceria abrasive often exhibits unusual characteristics that cannot be explained adequately by conventional polishing models based on pad/asperity elasticity or pressure distribution over features. Most notably, non-conventional, observed behaviors can be collected under the rubric of “slow start phenomena”. In this work, it is asserted that specific polishing characteristics of ceria slurry are largely due to the detailed surface chemistry of ceria particles and their interaction with silica. In any case, it is further shown that modification of slurry lubrication can alleviate slow-start and shift CMP process characteristics back toward more conventional behavior.

Type
Research Article
Copyright
Copyright © Materials Research Society 2004

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. Nabavi, M., Spalla, O., and Cabane, B., J. Coll. and Interf. Sci., 160, 459 (1993).Google Scholar
2. Behrens, S. H. and Grier, D. G., J. Chem. Phys., 115(14), 6716 (2001).Google Scholar
3. Hiemstra, T., Riemsdijk, W. H. Van, and Bolt, G. H., J. Coll. and Interf. Sci., 133, 91 (1989); T. Hiemstra, J. C. M. De Wit, and W. H. Van Riemsdijk, J. Coll. and Interf. Sci., 133, 105 (1989).Google Scholar
4. Cook, L. M., J. of Non-Crystalline Solids 120, 152, (1990).Google Scholar
5. Stein, D. J., Hetherington, D. L., Stevens, J. E., Oliver, M. R., Hosali, S. D., and Evans, D. R., MRS Meeting-Spring 1999, San Francisco, CA, Apr. 5-9, 1999.Google Scholar