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Proceedings Paper

Fundamentals Of Topographic Substrate Leveling
Author(s): L. E. Stillwagon; R. G. Larson
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Paper Abstract

The leveling of 100 - 500 μm wide, 1 pm deep isolated holes and trenches by 1 - 3 μm thick silicone oil films was observed by measuring film thickness changes at the centers of the features using a non-contact, interferometric technique. The dependence of the leveling time t on feature width w, film viscosity n and the initial film thickness h0 was investigated and compared to theoretical predictions. Experimental data were obtained for various values of w, n and ho. Except when the film thickness was about 1 μm the data for each different type of geometry fell on a single curve when the degree of leveling or planarization was plotted against T E tyh03/nw4 where y is the surface tension of the film. At the same value of T, the degree of planarization of isolated holes was about twice that of isolated trenches. The planarization vs. T curves should apply to all Newtonian liquids and may be used to predict the degree of planarization that will be achieved at specified leveling times by materials having specified values of n, h0 and Y. Thus, the curves may be useful in selecting planarizing materials for semiconductor fabrication steps that require substrate topography leveling. Simulations of the leveling process based on capillarity-driven flow were performed and agreed well with the experimental data. The simulations predicted some interesting and unexpected behavior that was observed experimentally. At short times the planarization worsened before improving at longer times, and "humps" appeared in the film profiles that apparently are a first step in minimizing surface energy. Such simulations may prove to be useful in predicting the difficulty of planarizing various types of topographic geometries.

Paper Details

Date Published: 1 January 1988
PDF: 9 pages
Proc. SPIE 0920, Advances in Resist Technology and Processing V, (1 January 1988); doi: 10.1117/12.968332
Show Author Affiliations
L. E. Stillwagon, AT&T Bell Laboratories (United States)
R. G. Larson, AT&T Bell Laboratories (United States)

Published in SPIE Proceedings Vol. 0920:
Advances in Resist Technology and Processing V
Scott A. MacDonald, Editor(s)

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