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US4803405A
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Plasma processing apparatus and method
Assignee: Koike Sanso Kogyo Co Ltd
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Filing: 1987-04-16
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Granted: 1989-02-07
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Expires: 2007-04-16
Abstract
Abstract The present invention relates to a plasma processing apparatus capable of obtaining a satisfactory plasma arc and a processing method used by this plasma processing apparatus. The plasma processing apparatus is constructed to vary an electric current or a voltage during start up at a fixed period for a fixed time. The plasma processing apparatus has a plasma power source capable of controlling an electric current or a voltage applied to a plasma torch, and an electrode and a nozzle are communicated by means of an electrification in the plasma torch. In a method for performing a plasma process by a plasma processing apparatus, a mixing gas has a ratio of Hydrogen to Argon in a range from 5 to 20 Vol %, and a frequency of a plasma electric current is controlled in a range from 10 to 30 KHz.
Inventors
- 👤 Etsuo Nakano
- 👤 Akira Furujo
- 👤 Tetsuya Iizuka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:42
CPC Classifications
H; H05; H05H; H05H1/00; H05H1/24; H05H1/26; H05H1/32; H05H1/34; H05H1/36; H05H1/3436
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
89 words
A method for operating a plasma processing apparatus comprising the steps of: first, generating a dc starting arc between an electrode and a nozzle of a dc plasma torch to ignite the torch, the torch having a primary gas and a secondary gas; second, increasing the dc arc current above a predetermined non zero lower limit; and thereafter, varying the dc arc current between the electrode and nozzle at a fixed period for a fixed time between said lower limit and an upper limit to start the plasma process.
Claim 2
Independent Claim
89 words
A method for operating a plasma processing apparatus comprising the steps of: first, generating a dc starting arc between an electrode and a nozzle of a dc plasma torch to ignite the torch, the torch having a primary gas and a secondary gas; second, increasing the dc arc current above a predetermined non zero lower limit; and thereafter, varying the dc arc current between the electrode and nozzle at a fixed period for a fixed time between said lower limit and an upper limit to start the plasma process.
Claim 3
Dependent Claim
33 words
The method of claim 1, wherein the primary gas is argon, the secondary gas is hydrogen, and a ratio of hydrogen to argon is in the range of 5 to 20 volume percent.
Claim 4
Dependent Claim
23 words
The method of claim 1, further comprising: controlling a frequency of a plasma electric current in a range of 10 to 30 KHz.
Claim 5
Dependent Claim
97 words
A plasma processing system comprising: a dc plasma torch having a nozzle electrode, a central electrode, and means for introducing at least one gas therebetween; and means for generating an initial arc between said central electrode and said nozzle electrode from a d.c. power supply, to ignite said at least one gas; means for increasing the d.c. current associated with said arc to a predetermined upper limit; and means for periodically varying said d.c. current between a predetermined non zero lower limit and said upper limit for a fixed number of periods, whereby stabilized starting is facilitated.
Claim 6
Dependent Claim
97 words
A plasma processing system comprising: a dc plasma torch having a nozzle electrode, a central electrode, and means for introducing at least one gas therebetween; and means for generating an initial arc between said central electrode and said nozzle electrode from a d.c. power supply, to ignite said at least one gas; means for increasing the d.c. current associated with said arc to a predetermined upper limit; and means for periodically varying said d.c. current between a predetermined non zero lower limit and said upper limit for a fixed number of periods, whereby stabilized starting is facilitated.
Claim 7
Independent Claim
102 words
A method of starting a plasma processing system, which system comprises a dc plasma torch having a nozzle electrode, a central electrode, and means for introducing at least one gas therebetween, the method comprising the steps of: generating an initial arc between said central electrode and said nozzle electrode from a d.c. power supply, to ignite said at least one gas; increasing the d.c. current associated with said arc to a predetermined upper limit; and periodically varying said d.c. current between a predetermined non zero lower limit and said upper limit for a fixed number of periods, whereby stabilized starting is facilitated.
Claim 8
Independent Claim
102 words
A method of starting a plasma processing system, which system comprises a dc plasma torch having a nozzle electrode, a central electrode, and means for introducing at least one gas therebetween, the method comprising the steps of: generating an initial arc between said central electrode and said nozzle electrode from a d.c. power supply, to ignite said at least one gas; increasing the d.c. current associated with said arc to a predetermined upper limit; and periodically varying said d.c. current between a predetermined non zero lower limit and said upper limit for a fixed number of periods, whereby stabilized starting is facilitated.
Claim 9
Dependent Claim
23 words
The method of claim 5, wherein the periodic variation of the dc current occurs at a frequency between 10 kHz and 30 kHz.
Claim 10
Dependent Claim
22 words
The method of claim 5, wherein the electric arc current varies in a range between about 15 amperes and about 20 amperes.
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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) | 1992-02-07 | 1992-08-08 | 1993-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-07 | 1996-08-08 | 1997-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-07 | 2000-08-08 | 2001-02-07 | $7700.00 | Window Closed / Lapsed |