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Proceedings Paper

Modelling Optical Linewidth Measurement Techniques In Order To Improve Precision And Accuracy.
Author(s): Chris P. Kirk; Andrew W. Gurnell
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Paper Abstract

Theoretical models for optical imaging are used to investigate the performance of different linewidth measurement techniques. The harmonic content of the image profiles of semiconductor line objects is examined around the focal plane and it is concluded that focusing techniques which utilise the lower harmonics are unreliable. The analysis is used to determine the spatial frequency range for which image based focus detection is possible and the performance of suitable digital spatial filters is investigated. The sensitivity of thin and thick layer measurements to variations in parameters such as thickness, refractive index and wavelength is investigated and it is concluded that measurement variations between specimens may be reduced by using a broad band illumination source. A method of reducing the spread of measurements by contrast correction is presented. A linewidth measurement technique based on image scanning is discussed and typical repeatability performance figures are presented for a purpose built system.

Paper Details

Date Published: 2 January 1986
PDF: 9 pages
Proc. SPIE 0565, Micron and Submicron Integrated Circuit Metrology, (2 January 1986); doi: 10.1117/12.949733
Show Author Affiliations
Chris P. Kirk, Leeds University (England)
Andrew W. Gurnell, Vickers Instruments (England)

Published in SPIE Proceedings Vol. 0565:
Micron and Submicron Integrated Circuit Metrology
Kevin M. Monahan, Editor(s)

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