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Proceedings Paper

Linesize effects on UV reflectance spectra
Author(s): David H. Ziger; Thomas Evans Adams; Joseph G. Garofalo
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Paper Abstract

We have investigated the effect of resist thickness, linewidth and pitch on UV reflectance spectra. This technique exploits the property that conventional novolak resists are very absorptive from 200 - 300 nm while substrates are significantly more reflective. For line/space developed resist features of constant pitch, we observe that the reflectance in this wavelength range varies periodically with (lambda) and increases linearly with decreasing linesize. The dominant factor in wavelength dependence is the constructive/destructive interference of the measurement light from the air/resist and air/substrate interfaces. Linesize dependence at constant pitch and resist thickness is predominantly controlled (within proper boundary condition regimes) by the percentage of the substrate exposed. The gross periodicity of the DUV reflection spectra for patterned films is correlated with resist thickness in a manner similar to the resist thickness dependence of UV reflection spectra for unpatterned films. Simulation of DUV reflectance from patterned films showed semiquantitative agreement with experimental results.

Paper Details

Date Published: 21 May 1996
PDF: 15 pages
Proc. SPIE 2725, Metrology, Inspection, and Process Control for Microlithography X, (21 May 1996); doi: 10.1117/12.240115
Show Author Affiliations
David H. Ziger, VLSI Technology Inc. (United States)
Thomas Evans Adams, AT&T Bell Labs. (United States)
Joseph G. Garofalo, AT&T Bell Labs. (United States)

Published in SPIE Proceedings Vol. 2725:
Metrology, Inspection, and Process Control for Microlithography X
Susan K. Jones, Editor(s)

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