Patent US4642728A successfully refreshed from Google Patents.
US4642728A
Expired / Lapsed
US
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Suppression of electrostatic charge buildup at a workplace
Assignee: Nokia Bell Labs
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Filing: 1985-10-24
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Granted: 1987-02-10
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Expires: 2005-10-24
Abstract
Abstract In order to suppress electrostatic charge buildup at a workplace, a wire having needle(s) connected thereto and extending vertically downward therefrom is suspended horizontally over the workplace, and a sequence of electrical pulses of alternating polarity is applied to the wire, each of the pulses having a pulse-width of the order of 1 second and a pulse-height of approximately 15 kilovolts.
Inventors
- 👤 Burton A. Unger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:57
CPC Classifications
H; H05; H05F; H05F3/00; H05F3/04
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
75 words
A method for processing a workpiece at a workplace comprising injecting successive showers alternately of positive and negative ions into a region of ambient atmosphere located above the workplace while the workpiece is located on a surface of the workplace for being processed thereat, each of the showers being generated during a separate time interval of the order of 1 second in duration whereby electrostatic charge buildup on the workpiece is suppressed by the showers.
Claim 2
Independent Claim
75 words
A method for processing a workpiece at a workplace comprising injecting successive showers alternately of positive and negative ions into a region of ambient atmosphere located above the workplace while the workpiece is located on a surface of the workplace for being processed thereat, each of the showers being generated during a separate time interval of the order of 1 second in duration whereby electrostatic charge buildup on the workpiece is suppressed by the showers.
Claim 3
Dependent Claim
72 words
In a method of manufacturing a circuit integrated in a semiconductor wafer the steps of: injecting successive showers alternately of positive and negative ions into a region of ambient atmosphere located above the workplace, each of the showers being generated during a separate time interval of the order of 1 second in duration while the wafer is located on a surface of the workplace; and processing the wafer thereat during said injecting.
Claim 4
Dependent Claim
72 words
In a method of manufacturing a circuit integrated in a semiconductor wafer the steps of: injecting successive showers alternately of positive and negative ions into a region of ambient atmosphere located above the workplace, each of the showers being generated during a separate time interval of the order of 1 second in duration while the wafer is located on a surface of the workplace; and processing the wafer thereat during said injecting.
Claim 5
Independent Claim
87 words
A method for processing a workpiece at a workplace the comprising the steps of: applying a sequence of electrical pulses of alternating polarity to one or more needles, located above the workplace, for injecting ions, in response to the pulses, into the ambient atmosphere of the workpiece while located at the workplace,; and processing the workpiece while said pulses are being applied, each of the pulses having a pulse-width of the order of 1 second whereby electrostatic charge buildup on the workpiece is suppressing by the ions.
Claim 6
Independent Claim
87 words
A method for processing a workpiece at a workplace the comprising the steps of: applying a sequence of electrical pulses of alternating polarity to one or more needles, located above the workplace, for injecting ions, in response to the pulses, into the ambient atmosphere of the workpiece while located at the workplace,; and processing the workpiece while said pulses are being applied, each of the pulses having a pulse-width of the order of 1 second whereby electrostatic charge buildup on the workpiece is suppressing by the ions.
Claim 7
Dependent Claim
13 words
The method of claim 3 in which the pulses are of alternating polarity.
Claim 8
Dependent Claim
22 words
The method of claim 4 in which the width of each pulse is in the approximate range of 1/5 to 4 seconds.
Claim 9
Independent Claim
93 words
A method for processing semiconductor wafers at a workplace comprising the steps of: applying a sequence of electrical pulses of alternating polarity to one or more needles, located above the workplace, for injecting ions, in response to the pulses, into the ambient atmosphere of the wafers while located at the workplace, each of the pulses having a pulse-width of the order of 1 second whereby electrostatic charge buildup at the workplace is suppressed by the ions while the wafers are located thereat; and processing the wafers thereat while said pulses are being applied.
Claim 10
Independent Claim
93 words
A method for processing semiconductor wafers at a workplace comprising the steps of: applying a sequence of electrical pulses of alternating polarity to one or more needles, located above the workplace, for injecting ions, in response to the pulses, into the ambient atmosphere of the wafers while located at the workplace, each of the pulses having a pulse-width of the order of 1 second whereby electrostatic charge buildup at the workplace is suppressed by the ions while the wafers are located thereat; and processing the wafers thereat while said pulses are being applied.
Claim 11
Dependent Claim
13 words
The method of claim 6 in which the pulses are of alternating polarity.
Claim 12
Dependent Claim
22 words
The method of claim 7 in which the width of each pulse is in the approximate range of 1/5 to 4 seconds.
Claim 13
Dependent Claim
22 words
The method of claim 6 in which the width of each pulse is in the approximate range of 1/5 to 4 seconds.
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) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |