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Acoustic-wave sensor for ambient monitoring of a photoresist-stripping agent

United States Patent

*** EXPIRED ***
August 18, 1998
View the Complete Patent at the US Patent & Trademark Office
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The acoustic-wave sensor. The acoustic-wave sensor is designed for ambient or vapor-phase monitoring of a photoresist-stripping agent such as N-methylpyrrolidinone (NMP), ethoxyethylpropionate (EEP) or the like. The acoustic-wave sensor comprises an acoustic-wave device such as a surface-acoustic-wave (SAW) device, a flexural-plate-wave (FPW) device, an acoustic-plate-mode (APM) device, or a thickness-shear-mode (TSM) device (also termed a quartz crystal microbalance or QCM) having a sensing region on a surface thereof. The sensing region includes a sensing film for sorbing a quantity of the photoresist-stripping agent, thereby altering or shifting a frequency of oscillation of an acoustic wave propagating through the sensing region for indicating an ambient concentration of the agent. According to preferred embodiments of the invention, the acoustic-wave device is a SAW device; and the sensing film comprises poly(vinylacetate), poly(N-vinylpyrrolidinone), or poly(vinylphenol).
Pfeifer; Kent B. (Los Lunas, NM), Hoyt; Andrea E. (Albuquerque, NM), Frye; Gregory C. (Cedar Crest, NM)
Sandia Corporation (Albuquerque, NM)
08/ 564,764
November 29, 1995
This invention was made with Government support under Contract No. DE-AC04-94AL85000 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.