Patent US4949670A successfully refreshed from Google Patents.
US4949670A
Expired / Lapsed
US
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Method and apparatus for low pressure plasma
Assignee: Motorola Solutions Inc
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Filing: 1988-11-04
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Granted: 1990-08-21
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Expires: 2008-11-04
Abstract
Abstract In a magnetically confined plasma, optimal pressure is found by measuring the peak to peak voltage of the plasma and looking for a distinct minimum in the peak to peak voltage. The pressure at which the minimum occurs can be used to calibrate a manometer used in the system.
Inventors
- 👤 Ole Krogh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:06
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32917; H01J37/32935; H01J37/32431; H01J37/3244
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
109 words
In apparatus for treating a semiconductor wafer with a glow discharge in a chamber including means for supplying one or more gases to said chamber, means for exhausting gases from said chamber, means for supplying RF power to said chamber, and means for magnetically confining said glow discharge, the improvement comprising: means coupled to said means for supplying RF power to said chamber for monitoring the peak to peak voltage within said chamber and producing a control signal in response thereto; and means for maintaining the pressure within said chamber at or near a pressure corresponding to a minimum peak to peak voltage in response to said control signal.
Claim 2
Dependent Claim
109 words
In apparatus for treating a semiconductor wafer with a glow discharge in a chamber including means for supplying one or more gases to said chamber, means for exhausting gases from said chamber, means for supplying RF power to said chamber, and means for magnetically confining said glow discharge, the improvement comprising: means coupled to said means for supplying RF power to said chamber for monitoring the peak to peak voltage within said chamber and producing a control signal in response thereto; and means for maintaining the pressure within said chamber at or near a pressure corresponding to a minimum peak to peak voltage in response to said control signal.
Claim 3
Dependent Claim
26 words
The apparatus as set forth in claim 1 wherein said means for maintaining comprises a gate valve interconnecting said means for exhausting gases and said chamber.
Claim 4
Dependent Claim
43 words
The apparatus as set forth in claim 1 wherein said means for maintaining comprises logic means coupled to said means for monitoring for detecting minima in said control signal and for providing corresponding pressure adjusting signals to said means for maintaining the pressure.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-08-20 | 1994-02-19 | 1994-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-20 | 1998-02-19 | 1998-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-20 | 2002-02-19 | 2002-08-21 | $7700.00 | Window Closed / Lapsed |