Patent US5620526A successfully refreshed from Google Patents.
US5620526A
Expired / Lapsed
US
⏱️ 0.0 years remaining
In-situ cleaning of plasma treatment chamber
Assignee: Fujitsu VLSI Ltd
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Filing: 1994-07-22
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Granted: 1997-04-15
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Expires: 2014-07-22
Abstract
Abstract A cleaning of a plasma chamber is done by a NF 3 plasma treatment (typically under 1 to 1.5 Torr). The etching rate of an oxide layer can be improved by inserting, between the NF 3 plasma treatments, a low pressure (lower than 10 -1 Torr) plasma treatment preferably in a plasma of oxygen, water vapor, silane, fluorine, a hydrate compound, nitrogen trifluoride, or a mixture of nitrogen trifluoride with at least one of hydrogen fluoride, fluorine, water vapor and hydride compounds.
Inventors
- 👤 Hirofumi Watatani
- 👤 Masahiko Doki
- 👤 Shoji Okuda
- 👤 Junya Nakahira
- 👤 Hideaki Kikuchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 11:54
CPC Classifications
C; C09; C09K; C09K13/00; C09K13/04; C09K13/08; C23; C23C; C23C16/00; C23C16/44; C23C16/4401; C23C16/4405
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
140 words
A process for in-situ cleaning of a plasma treatment chamber, said process comprising the steps of: conducting a first plasma treatment in a plasma treatment chamber with nitrogen trifluoride plasma at a first pressure, so as to remove an oxide layer previously deposited inside the plasma treatment chamber; conducting a second plasma treatment in said plasma treatment chamber at a second pressure lower than said first pressure, said second plasma treating being conducted in a plasma of a gas selected from a group consisting of oxygen, water vapor, silane, fluorine, nitrogen trifluoride, or a mixture of nitrogen trifluoride with at least one of hydrogen fluoride, fluorine, and water vapor; and a third plasma treatment in said plasma treatment chamber with nitrogen trifluoride plasma at a third pressure higher than said second pressure, so as to further remove said oxide layer.
Claim 2
Dependent Claim
140 words
A process for in-situ cleaning of a plasma treatment chamber, said process comprising the steps of: conducting a first plasma treatment in a plasma treatment chamber with nitrogen trifluoride plasma at a first pressure, so as to remove an oxide layer previously deposited inside the plasma treatment chamber; conducting a second plasma treatment in said plasma treatment chamber at a second pressure lower than said first pressure, said second plasma treating being conducted in a plasma of a gas selected from a group consisting of oxygen, water vapor, silane, fluorine, nitrogen trifluoride, or a mixture of nitrogen trifluoride with at least one of hydrogen fluoride, fluorine, and water vapor; and a third plasma treatment in said plasma treatment chamber with nitrogen trifluoride plasma at a third pressure higher than said second pressure, so as to further remove said oxide layer.
Claim 3
Dependent Claim
16 words
A process according to claim 1, wherein said second pressure is lower than 10 -1 Torr.
Claim 4
Dependent Claim
16 words
A process according to claim 1, wherein said second pressure is lower than 10 -3 Torr.
Claim 5
Dependent Claim
17 words
A process according to claim 1, wherein said second plasma treatment is conducted in an oxygen plasma.
Claim 6
Dependent Claim
19 words
A process according to claim 1, wherein said second plasma treatment is conducted in a plasma of nitrogen trifluoride.
Claim 7
Dependent Claim
18 words
A process according to claim 1, wherein said second plasma treatment is conducted in a plasma of silane.
Claim 8
Dependent Claim
26 words
A process according to claim 1, wherein said first and/or third plasma treatments are conducted in a plasma of a mixture of nitrogen trifluoride and fluorine.
Claim 9
Dependent Claim
34 words
A process according to claim 1, wherein said third plasma treatment is conducted under the same conditions as those of said first plasma treatment and said first and second plasma treatments are cyclically repeated.
Claim 10
Dependent Claim
15 words
A process according to claim 1, wherein said plasma chamber is a microwave plasma chamber.
Claim 11
Dependent Claim
19 words
A process according to claim 1, wherein said first pressure is in a range of 1 to 1.5 Torr.
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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) | 2000-04-14 | 2000-10-14 | 2001-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-04-14 | 2004-10-14 | 2005-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-04-14 | 2008-10-14 | 2009-04-15 | $7700.00 | Window Closed / Lapsed |