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Patent US5795993A successfully refreshed from Google Patents.
US5795993A
Expired / Lapsed
US
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Acoustic-wave sensor for ambient monitoring of a photoresist-stripping agent
Assignee: National Technology and Engineering Solutions of Sandia LLC
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Filing: 1995-11-29
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Granted: 1998-08-18
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Expires: 2015-11-29
Abstract
Abstract 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).
Inventors
- 👤 Kent B. Pfeifer
- 👤 Andrea E. Hoyt
- 👤 Gregory C. Frye
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:35
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/02; G01N29/022; G01N2291/00; G01N2291/01; G01N2291/014; G01N2291/02; G01N2291/025; G01N2291/0256; G01N2291/028; G01N2291/02809; G01N2291/02881; G01N2291/04; G01N2291/042; G01N2291/0422; G01N2291/0423; G01N2291/0426; G01N2291/0427
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
93 words
An acoustic-wave sensor for measuring an ambient concentration of a low-volatility photoresist-stripping agent comprising; an acoustic-wave device having a sensing region on a surface thereof, the sensing region including a photoresist-stripping-agent sensing film; a housing for holding the acoustic-wave sensor: and sampling means for providing a flow of ambient air in contact with the sensing film for sorbing a quantity of the low-volatility photoresist-stripping agent and thereby altering a frequency of an acoustic wave propagating through the sensing region, the altered frequency providing an indication of the ambient concentration of the photoresist-striping agent.
Claim 2
Dependent Claim
93 words
An acoustic-wave sensor for measuring an ambient concentration of a low-volatility photoresist-stripping agent comprising; an acoustic-wave device having a sensing region on a surface thereof, the sensing region including a photoresist-stripping-agent sensing film; a housing for holding the acoustic-wave sensor: and sampling means for providing a flow of ambient air in contact with the sensing film for sorbing a quantity of the low-volatility photoresist-stripping agent and thereby altering a frequency of an acoustic wave propagating through the sensing region, the altered frequency providing an indication of the ambient concentration of the photoresist-striping agent.
Claim 3
Dependent Claim
22 words
The acoustic-wave sensor of claim 1 wherein the acoustic-wave device includes at least one transducer for generating or detecting the acoustic wave.
Claim 4
Dependent Claim
26 words
The acoustic-wave sensor of claim 1 further including means connected to the acoustic-wave device for generating the acoustic wave, and for sensing the altered frequency thereof.
Claim 5
Dependent Claim
33 words
The acoustic-wave sensor of claim 3 wherein the electrical means in combination with the acoustic-wave device forms a free-running oscillator, with the acoustic-wave device being connected in a feedback loop of the oscillator.
Claim 6
Dependent Claim
27 words
The acoustic-wave sensor of claim 1 wherein the acoustic-wave device is selected from the group consisting of surface-acoustic-wave devices, flexural-plate-wave devices, acoustic-plate-mode devices and thickness-shear mode devices.
Claim 7
Dependent Claim
21 words
The acoustic-wave sensor of claim 3 further including a reference acoustic-wave device for providing a reference frequency to the electrical means.
Claim 8
Dependent Claim
19 words
The acoustic-wave sensor of claim 6 wherein the reference acoustic-wave device is isolated from contact with the photoresist-stripping agent.
Claim 9
Dependent Claim
25 words
The acoustic-wave sensor of claim 6 wherein the reference acoustic-wave device includes a reference sensing region that is substantially non-sorbing of the low-volatility photoresist-stripping agent.
Claim 10
Dependent Claim
23 words
The acoustic-wave sensor of claim 1 wherein the low-volatility photoresist-stripping agent is selected from the group consisting of N-methylpyrrolidinone (NMP) and ethoxyethylpropionate (EEP).
Claim 11
Dependent Claim
21 words
The acoustic-wave sensor of claim 9 wherein the sensing film is selected from the group consisting of poly(vinylacetate), poly(N-vinylpyrrolidinone), and poly(vinylphenol).
Claim 12
Dependent Claim
146 words
An acoustic-wave sensor for measuring an ambient concentration of a low-volatility photoresist-stripping agent comprising: (a) a surface-acoustic-wave (SAW) device having a pair of interdigitated transducers with a plurality of fingers thereof spaced apart on a quartz substrate and further including on the substrate between the transducers a sensing region including a sensing film for sorbing at least a part of the low-volatility photoresist-stripping agent; (b) housing for holding the SAW device; (c) sampling means for providing a flow of ambient air in contact with the sensing film for sorbing the low-volatility photoresist-striping agent; and (d) electrical means connected to the transducers for activating the transducers and measuring a frequency of a surface acoustic wave propagating between the transducers, the frequency being shifted in response to sorption of the photoresist-striping agent, with the frequency shift providing an indication of the ambient concentration of the low-volatility photoresist-stripping agent.
Claim 13
Dependent Claim
146 words
An acoustic-wave sensor for measuring an ambient concentration of a low-volatility photoresist-stripping agent comprising: (a) a surface-acoustic-wave (SAW) device having a pair of interdigitated transducers with a plurality of fingers thereof spaced apart on a quartz substrate and further including on the substrate between the transducers a sensing region including a sensing film for sorbing at least a part of the low-volatility photoresist-stripping agent; (b) housing for holding the SAW device; (c) sampling means for providing a flow of ambient air in contact with the sensing film for sorbing the low-volatility photoresist-striping agent; and (d) electrical means connected to the transducers for activating the transducers and measuring a frequency of a surface acoustic wave propagating between the transducers, the frequency being shifted in response to sorption of the photoresist-striping agent, with the frequency shift providing an indication of the ambient concentration of the low-volatility photoresist-stripping agent.
Claim 14
Dependent Claim
33 words
The acoustic-wave sensor of claim 11 wherein the electrical means in combination with the SAW device forms a free-running oscillator, with the SAW device being connected in a feedback loop of the oscillator.
Claim 15
Dependent Claim
21 words
The acoustic-wave sensor of claim 11 further including a reference SAW device for providing a reference frequency to the electrical means.
Claim 16
Dependent Claim
23 words
The acoustic-wave sensor of claim 11 wherein the low-volatility photoresist-stripping agent is selected from the group consisting of N-methylpyrrolidinone (NMP) and ethoxyethylpropionate (EEP).
Claim 17
Dependent Claim
21 words
The acoustic-wave sensor of claim 14 wherein the sensing film is selected from the group consisting of poly(vinylacetate), poly(N-vinylpyrrolidinone), and poly(vinylphenol).
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-08-17 | 2002-02-16 | 2002-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-17 | 2006-02-16 | 2006-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-17 | 2010-02-16 | 2010-08-18 | $7700.00 | Window Closed / Lapsed |