Patent US4836902A successfully refreshed from Google Patents.
US4836902A
Expired / Lapsed
US
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Method and apparatus for removing coating from substrate
Assignee: Nortel Networks Ltd
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Filing: 1987-10-09
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Granted: 1989-06-06
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Expires: 2007-10-09
Abstract
Abstract In a method and apparatus for plasma stripping a polymer photoresist coating from a semiconductor substrate, ultraviolet radiation generated as a byproduct of plasma generation is absorbed by a baffle placed between a plasma source and the substrate. The baffle inhibits incidence of ultraviolet light on the substrate while permitting flow of activated gas onto the substrate to chemically strip the photoresist from the substrate. Use of the baffle reduces microscopic damage to the substrate.
Inventors
- 👤 Alexander Kalnitsky
- 👤 Joseph P. Ellul
- 👤 Sing P. Tay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:05
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32431; H01J37/32798; H01J37/32853; H01J37/32871; G; G03; G03F; G03F7/00; G03F7/26; G03F7/42; G03F7/427; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/286; H10P50/287
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
112 words
A method for removing a layer of coating material from a silicon substrate, comprising: activating a gas in an activation chamber; and absorbing ultraviolet radiation generated during activation of the gas at at least one ulraviolet radiation absorbing surface which is constructed of polysilicon and passivated by oxidation, said at least one ultraviolet radiation absorbing surface being arranged to block any straight line path from the activation chamber to the silicon substrate; while passing the activated gas from the activation chamber past the at least one ultraviolet radiation absorbing surface and into contact with the layer of coating material to break down the coating material and strip it from the silicon substrate.
Claim 2
Independent Claim
112 words
A method for removing a layer of coating material from a silicon substrate, comprising: activating a gas in an activation chamber; and absorbing ultraviolet radiation generated during activation of the gas at at least one ulraviolet radiation absorbing surface which is constructed of polysilicon and passivated by oxidation, said at least one ultraviolet radiation absorbing surface being arranged to block any straight line path from the activation chamber to the silicon substrate; while passing the activated gas from the activation chamber past the at least one ultraviolet radiation absorbing surface and into contact with the layer of coating material to break down the coating material and strip it from the silicon substrate.
Claim 3
Dependent Claim
34 words
A method as defined in claim 1, wherein the coating is polymer photoresist and the gas is selected from a group consisting of O 2 , CF 4 , SF 6 and freon gas.
Claim 4
Dependent Claim
26 words
A method as defined in claim 1, wherein the gas is activated by application of a microwave or radio frequency electric field to generate a plasma.
Claim 5
Dependent Claim
17 words
A method as defined in claim 1, wherein the gas is activated by application of ultraviolet radiation.
Claim 6
Dependent Claim
36 words
A method as defined in claim 1, wherein the activated gas is drawn from the activation chamber past the at least one surface and into contact with the coating material by means of a pressure differential.
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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) | 1992-06-05 | 1992-12-05 | 1993-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-05 | 1996-12-05 | 1997-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-05 | 2000-12-05 | 2001-06-06 | $7700.00 | Window Closed / Lapsed |