US4567938A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for controlling thermal transfer in a cyclic vacuum processing system
Assignee: Varian Semiconductor Equipment Associates Inc
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Filing: 1985-06-10
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Granted: 1986-02-04
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Expires: 2005-06-10
Abstract
Abstract Apparatus for providing thermal transfer between a semiconductor wafer and a heat sink or source in a vacuum processing chamber includes a platen against which the wafer is sealed to define a thermal transfer region therebetween. The platen includes a passage for gas flow between the chamber and the thermal transfer region. The apparatus further includes a valve for controllably opening and closing the passage and a controller for closing the valve when the pressure in the chamber reaches a predetermined value. Gas at the predetermined pressure, typically 0.5 to 100 Torr, is trapped in the thermal transfer region and conducts thermal energy between the workpiece and the platen. In a preferred embodiment, a plurality of platens are positioned on a rotating disc in an ion implantation system and a centrifugally operated valve is utilized to close the passage.
Inventors
- 👤 Norman L. Turner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:47
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/04; H10P72/0431; H10P72/0432; Y; Y10; Y10S; Y10S269/00; Y10S269/903
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
137 words
A method for providing enhanced thermal transfer between a workpiece and a heat sink in an ion implantation system including a vacuum chamber adapted for venting during a portion of its operating cycle and vacuum pumping to a low pressure during another portion of said cycle, said method comprising the steps of: providing a platen against which said workpiece is sealed to define a thermal transfer region, said platen including a passage for gas flow between said chamber and said thermal transfer region; closing said passage in said platen when the pressure in said chamber reaches a predetermined intermediate pressure during vacuum processing; opening said passage in said platen during venting, whereby gas at said intermediate pressure is trapped in said thermal transfer region during vacuum processing and conducts thermal energy between said workpiece and said platen.
Claim 2
Independent Claim
137 words
A method for providing enhanced thermal transfer between a workpiece and a heat sink in an ion implantation system including a vacuum chamber adapted for venting during a portion of its operating cycle and vacuum pumping to a low pressure during another portion of said cycle, said method comprising the steps of: providing a platen against which said workpiece is sealed to define a thermal transfer region, said platen including a passage for gas flow between said chamber and said thermal transfer region; closing said passage in said platen when the pressure in said chamber reaches a predetermined intermediate pressure during vacuum processing; opening said passage in said platen during venting, whereby gas at said intermediate pressure is trapped in said thermal transfer region during vacuum processing and conducts thermal energy between said workpiece and said platen.
Claim 3
Dependent Claim
35 words
The method as defined in claim 1 wherein said step of closing said passage includes the step of sensing the pressure in said chamber and closing said passage when the pressure reaches said intermediate pressure.
Claim 4
Dependent Claim
66 words
The method as defined in claim 2 wherein said step of providing a platen further includes providing a disc on which said platen is mounted and providing a centrifugally operated valve for closing said passage and wherein the step of closing said passage includes the step of rotating said disc at a speed sufficient to close said centrifugally operated valve when said intermediate pressure is reached.
References Cited (Backward Citations)
US3566960A
Cited
US4139051A
Cited
US4282924A
Cited
US4261762A
Cited
US4453080A
Cited
US4512391A
Cited
US4457359A
Cited
US4458746A
Cited
US4491173A
Cited
US4542298A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-03 | 1989-08-05 | 1990-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-03 | 1993-08-05 | 1994-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-03 | 1997-08-05 | 1998-02-04 | $7700.00 | Window Closed / Lapsed |