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Improved Planarization for a Sog Etchback Process by Modifying the PECVD Oxide Film

Published online by Cambridge University Press:  25 February 2011

Milind Weling
Affiliation:
VLSI Technology Inc., 1109 McKay Drive, San Jose, CA 95131. Tel: (408) 434–3000 X2411, X3332
Vivek Jain
Affiliation:
VLSI Technology Inc., 1109 McKay Drive, San Jose, CA 95131. Tel: (408) 434–3000 X2411, X3332
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Abstract

In this study we have shown, for the first time, that Inter-Metal Oxide (IMO) planarization using a spin-on-glass (SOG) etchback process can be significantly improved by changing the composition of the deposited PECVD oxide film. Earlier studies have emphasized the importance of lowering the SOG to PECVD oxide etch selectivity below unity to compensate for micro-loading effects and thereby achieve good planarization. However, we have shown that a range of selectivities could be obtained by merely changing the silicon-richness of the PECVD oxide film. It was observed that for a given etch selectivity, planarization after SOG etchback was better with a silicon-rich oxide than with a stoichiometric oxide and particularly so for tight spacings that are characteristic of sub-micron technologies. We believe that increasing the silicon-richness of the PECVD oxide suppresses the micro-loading effects and consequently enables operation at selectivities closer to unity while maintaining good planarization. This feature has an important advantage of significantly widening the process window for a SOG etchback application.

Type
Research Article
Copyright
Copyright © Materials Research Society 1992

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References

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