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Proceedings Paper

Carbon contamination removal in larger chambers with low-power downstream plasma cleaning
Author(s): C. G. Morgan; R. Vane
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Paper Abstract

There is a need for pristine vacuum environments free of carbon contamination in many lithography tools. Carbon is a particularly irksome contaminant due to its ubiquity and its reactivity with energetic electron or EUV photon beams. When residual hydrocarbons land on a surface that is being impinged by an energetic beam, they will crack and reform as less mobile deposits. Carbon buildup cause loss in image resolution resulting in line width measurement increases during multiple CD-SEM scans, and on EUV optics it can lead to lower reflectivity and throughput of a lithography system. A new downstream plasma cleaner has been developed to clean larger chambers at lower pressures and higher RF plasma power (50W) and operates efficiently with current turbomolecular pumps. Cleaning rates can be measured by using a quartz crystal microbalance (QCM) with its surface previously contaminated with hydrocarbons. Rates have been measured at over 1 nm/minute at a distance of over 0.5 m from the plasma source. The cleaner can be used with room air, oxygen gas mixtures, and hydrogen gas. Although it is slightly larger than the currently available Evactron® De-Contaminator, it still has a compact footprint which allows it to be easily installed on lithography tools. This paper will explore the operation of the new plasma cleaner, examining the effect of the cleaning rate due to changes in various conditions including power, pressure and distance from the plasma source.

Paper Details

Date Published: 3 April 2012
PDF: 8 pages
Proc. SPIE 8324, Metrology, Inspection, and Process Control for Microlithography XXVI, 83242F (3 April 2012); doi: 10.1117/12.917786
Show Author Affiliations
C. G. Morgan, XEI Scientific, Inc. (United States)
R. Vane, XEI Scientific, Inc. (United States)

Published in SPIE Proceedings Vol. 8324:
Metrology, Inspection, and Process Control for Microlithography XXVI
Alexander Starikov, Editor(s)

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