US4246060A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plasma development process controller
Assignee: Motorola Solutions Inc
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Filing: 1979-01-02
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Granted: 1981-01-20
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Expires: 1999-01-02
Abstract
Abstract End point detection in developing photoresist is accomplished by monitoring the output of a photodetector and sensing a plateau in the output.
Inventors
- 👤 Jed V. Keller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:14
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32917; H01J37/32935; G; G01; G01N; G01N21/00; G01N21/75; G01N21/76
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
92 words
In apparatus for plasma etching having an evacuable chamber, for containing a gas etchant and the material to be etched, and a source of radio frequency energy coupled to the interior of said chamber for sustaining a plasma, the improvement comprising: photodetector means optically coupled to the interior of said chamber for producing a variable level output signal representative of the luminosity of said plasma; and means for detecting a temporary uniformity in the level of said output signal as indicative of the end of a first phase of said plasma etch.
Claim 2
Dependent Claim
92 words
In apparatus for plasma etching having an evacuable chamber, for containing a gas etchant and the material to be etched, and a source of radio frequency energy coupled to the interior of said chamber for sustaining a plasma, the improvement comprising: photodetector means optically coupled to the interior of said chamber for producing a variable level output signal representative of the luminosity of said plasma; and means for detecting a temporary uniformity in the level of said output signal as indicative of the end of a first phase of said plasma etch.
Claim 3
Dependent Claim
20 words
The apparatus as set forth in claim 1 wherein said detecting means detects a predetermined level in said output signal.
Claim 4
Dependent Claim
20 words
The apparatus as set forth in claim 1 and further comprising means for recording the output of said photodetector means.
Claim 5
Dependent Claim
37 words
The apparatus as set forth in claim 1 and further comprising control means connected to said level detecting means and to said source of radio frequency energy for turning off said source when said uniformity is detected.
Claim 6
Dependent Claim
18 words
The apparatus of claim 1 wherein said photodetector means comprises a photocell and a current to voltage converter.
Claim 7
Dependent Claim
24 words
The apparatus as set forth in claim 5 wherein said photodetector means further comprises spectral filter means interposed between said photocell and said plasma.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-20 | 1984-07-21 | 1985-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-20 | 1988-07-21 | 1989-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-20 | 1992-07-21 | 1993-01-20 | $7700.00 | Window Closed / Lapsed |