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Proceedings Paper

Contamination monitoring for ammonia, amines, and acid gases utilizing ion mobility spectroscopy (IMS)
Author(s): Tad Bacon; Kurt Webber; Ronald A. Carpio
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Paper Abstract

The effect of ammonia (NH3) and n-methyl pyrrolidinone (NMP) contamination on chemically amplified DUV resists is well documented. Other amines and related compounds are under suspicion as well. In addition, the concentration levels that are of concern have steadily decreased from approximately 10 ppbv down to levels as low as 0.1 ppbv. While some techniques such as ion chromotagraphy (IC) have been demonstrated to have limits of detection at these levels, the analysis times are rather long and cumbersome. This paper describes the use of IMS to perform these measurements, in a totally automated, continuous instrument. IMS is a simplified time-of-flight technique that requires no liquid reagents and has been demonstrated to be a reliable method for monitoring for ammonia and NMP in cleanrooms. This paper demonstrates the ability of the technique to monitor for amines such as dimethylamine, methylamine, methanolamine, ethanolamine, diethanolamine, butylamine and others. Detection limits of 0.1 ppbv and below are clearly demonstrated. Also discussed are methods of monitoring multiple points with a single analyzer. Ability to detect corrosive gases such as hydrogen fluoride (HF), hydrogen chloride (HCl), sulfur dioxide (SO2), sulfur trioxide (SO3), nitrogen dioxide (NO2), chlorine (Cl2), bromine (Br2), phosphoric acid (H3PO4) are also demonstrated.

Paper Details

Date Published: 8 June 1998
PDF: 10 pages
Proc. SPIE 3332, Metrology, Inspection, and Process Control for Microlithography XII, (8 June 1998); doi: 10.1117/12.308766
Show Author Affiliations
Tad Bacon, Molecular Analytics (United States)
Kurt Webber, Molecular Analytics (United States)
Ronald A. Carpio, SEMATECH (United States)

Published in SPIE Proceedings Vol. 3332:
Metrology, Inspection, and Process Control for Microlithography XII
Bhanwar Singh, Editor(s)

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