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In Situ Spectroscopic Ellipsometry for the Real Time Process Control of Plasma Etching of Silicon Nitride

Published online by Cambridge University Press:  10 February 2011

I. G. Rosen ,
T. Parent ,
B. Fidan  and
A. Madhukar
I. G. Rosen
Affiliation:
Center for the Intelligent Manufacturing of Semiconductors (CIMOS), University of Southern California, Los Angeles, CA 90089 USA
T. Parent
Affiliation:
Center for the Intelligent Manufacturing of Semiconductors (CIMOS), University of Southern California, Los Angeles, CA 90089 USA
B. Fidan
Affiliation:
Center for the Intelligent Manufacturing of Semiconductors (CIMOS), University of Southern California, Los Angeles, CA 90089 USA
A. Madhukar
Affiliation:
Center for the Intelligent Manufacturing of Semiconductors (CIMOS), University of Southern California, Los Angeles, CA 90089 USA
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Abstract

Spectroscopic ellipsometry (SE) is a commonly used non-destructive, non-invasive in-situ sensor for dry etching. SE measures the change in the polarization state of light reflected from a surface. Sample thickness is obtained by fitting a model to the experimental ellipsometry data. In this paper we describe the design, testing and evaluation of an SE based adaptive real time feedback controller for etch rate regulation in CF4/O2 plasma etching of silicon nitride films. The feedback variable is the current etch rate as determined from the in-situ SE measurements of the film's thickness. The controller compensates for drifts in etch rate which occur during a given etch, and adaptively adjusts for the run-to-run variability inherent to plasma processing. Experimental results are presented and discussed.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 591 , 1999 , 263
Copyright
Copyright © Materials Research Society 2000

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References

REFERENCES

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