Patent US4902631A successfully refreshed from Google Patents.
US4902631A
Expired / Lapsed
US
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Monitoring the fabrication of semiconductor devices by photon induced electron emission
Assignee: Nokia Bell Labs
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Filing: 1988-10-28
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Granted: 1990-02-20
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Expires: 2008-10-28
Abstract
Abstract Gas phase processes such as plasma etching of a semiconductor substrate is monitored by utilizing the optogalvanic effect. The substrate is subjected to light and in response emits an electron current whose magnitude is representative of the composition at the surface of the substrate. The monitored current is a sensitive indication of surface contamination and of compositional changes associated with the gas phase procedure. The technique is effectively utilized in fabricating devices such as semiconductor devices.
Inventors
- 👤 Stephen W. Downey
- 👤 Richard A. Gottscho
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:19
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32917; H01J37/32935; Y; Y10; Y10S; Y10S148/00; Y10S148/051
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
90 words
A process for fabricating a device comprising the steps of subjecting a substrate to a gas phase species to induce a change in said substrate and employing said changed substrate to effect said fabrication characterized in that during said change, said substrate is subjected to non-particle electromagnetic radiation that induces formation of free electrons in said substrate, said electrons are monitored and said change is either terminated, adjusted, or allowed to continue based on said monitoring wherein said change is induced by a source other than said non-particle electromagnetic radiation.
Claim 2
Dependent Claim
90 words
A process for fabricating a device comprising the steps of subjecting a substrate to a gas phase species to induce a change in said substrate and employing said changed substrate to effect said fabrication characterized in that during said change, said substrate is subjected to non-particle electromagnetic radiation that induces formation of free electrons in said substrate, said electrons are monitored and said change is either terminated, adjusted, or allowed to continue based on said monitoring wherein said change is induced by a source other than said non-particle electromagnetic radiation.
Claim 3
Dependent Claim
18 words
The process of claim 1 wherein said change comprises etching of at least a portion of said substrate.
Claim 4
Dependent Claim
13 words
The process of claim 2 wherein said species is generated in a plasma.
Claim 5
Dependent Claim
20 words
The process of claim 3 wherein said substrate is subjected to said species at a position removed from said plasma.
Claim 6
Dependent Claim
13 words
The process of claim 1 wherein said species is generated in a plasma.
Claim 7
Dependent Claim
17 words
The process of claim 1 wherein said change comprises a deposition of a material onto said substrate.
Claim 8
Dependent Claim
13 words
The process of claim 6 wherein said species is generated in a plasma.
Claim 9
Dependent Claim
20 words
The process of claim 7 wherein said substrate is subjected to said species at a position removed from said plasma.
Claim 10
Dependent Claim
20 words
The process of claim 1 wherein said monitoring comprises determining the change in current with time due to said electrons.
Claim 11
Dependent Claim
21 words
The process of claim 9 wherein said termination is instituted due to a deviation of said current from a prototypical level.
Claim 12
Dependent Claim
21 words
The process of claim 9 wherein said termination is instituted when a change in composition of said substrate surface is indicated.
Claim 13
Dependent Claim
14 words
The process of claim 11 wherein said change in composition is due to etching.
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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) | 1993-02-19 | 1993-08-21 | 1994-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-19 | 1997-08-21 | 1998-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-19 | 2001-08-21 | 2002-02-20 | $7700.00 | Window Closed / Lapsed |