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Proceedings Paper

In-situ spectral ellipsometry for real-time thickness measurement and control
Author(s): Steven A. Henck; Walter M. Duncan; Lee M. Loewenstein; John Kuehne
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Paper Abstract

A polarization modulated spectroscopic ellipsometer (SE) is used in situ to measure the thicknesses of films in real time during processing. These thicknesses are used for adaptive control during single-wafer processing. Using the speed of phase modulation, multichannel detection, and digital signal processing techniques, this ellipsometer is capable of acquiring spectra in less than 75 ms. Efficient algorithms were developed for determining layer parameters (thicknesses and composition) from the measured spectra of multilayer film stacks in one second or less. The measured thicknesses and etch rates are used to anticipate interfaces in multiple layer stacks and control process end points. A repeatability gauge study was performed using this in situ SE and a commercial single-wavelength ellipsometer (SWE) on thermally grown silicon dioxide on silicon wafers. Data was obtained on each instrument over an oxide thickness range from 60 to 250 angstroms. The total repeatability for the in situ SE measurements was 0.26 angstroms (1.6 angstroms 6-sigma) over this thickness range.

Paper Details

Date Published: 16 April 1993
PDF: 10 pages
Proc. SPIE 1803, Advanced Techniques for Integrated Circuit Processing II, (16 April 1993); doi: 10.1117/12.142925
Show Author Affiliations
Steven A. Henck, Texas Instruments Inc. (United States)
Walter M. Duncan, Texas Instruments Inc. (United States)
Lee M. Loewenstein, Texas Instruments Inc. (United States)
John Kuehne, Texas Instruments Inc. (United States)

Published in SPIE Proceedings Vol. 1803:
Advanced Techniques for Integrated Circuit Processing II
James A. Bondur; Gary Castleman; Lloyd R. Harriott; Terry R. Turner, Editor(s)

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