US5560776A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Plasma discharge generating antenna
Assignee: Toshiba Corp
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Filing: 1994-09-09
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Granted: 1996-10-01
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Expires: 2014-09-09
Abstract
Abstract A plasma discharge apparatus includes a chamber in which plasma discharge is produced; an antenna composed of a loop coil formed from an electric conductor which can be supplied with R.F. power so as to produce a high frequency electric field in the chamber; and an electric shield of a shield layer of non-magnetic electrically conductive material which toroidally surrounds the coil and which has openings. The shield layer is grounded and electrically connected to the antenna so as to be a return circuit. The electric shield can be formed from a strip electric conductor toroidally wound to provide a spiral gap opening between turns. The strip can further be toroidally wound over the spiral gap but separated from the underlying strip layer to form a double layer shield.
Inventors
- 👤 Hideo Sugai
- 👤 Katsutaro Ichihara
- 👤 Nobuaki Yasuda
- 👤 Michiko Okubo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:58
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32009; H01J37/32082; H01J37/321; H01J37/3211; H01J37/32431; H01J37/32623; H01J37/32651; H01Q; H01Q1/00; H01Q1/12; H01Q1/22; H01Q1/26
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
121 words
A plasma discharge apparatus usable with a source of R.F. power, the apparatus comprising: a chamber in which plasma discharge is to be produced; a loop coil antenna formed from an electric conductor and which can be operatively connected to the source of R.F. power, said coil being positioned to produce a high frequency electric field in the chamber; an electric shield including at least one shielding layer of a non-magnetic electrically conductive material, said layer being electrically connected to the antenna so as to comprise a return circuit and being positioned to surround said coil toroidally, wherein the electric shield comprises an electrically conductive portion and an electrically non-conductive portion; and means for fixing the electric potential of said shield.
Claim 2
Dependent Claim
121 words
A plasma discharge apparatus usable with a source of R.F. power, the apparatus comprising: a chamber in which plasma discharge is to be produced; a loop coil antenna formed from an electric conductor and which can be operatively connected to the source of R.F. power, said coil being positioned to produce a high frequency electric field in the chamber; an electric shield including at least one shielding layer of a non-magnetic electrically conductive material, said layer being electrically connected to the antenna so as to comprise a return circuit and being positioned to surround said coil toroidally, wherein the electric shield comprises an electrically conductive portion and an electrically non-conductive portion; and means for fixing the electric potential of said shield.
Claim 3
Dependent Claim
11 words
Apparatus according to claim 1, wherein the electric shield is grounded.
Claim 4
Dependent Claim
34 words
Apparatus according to claim 1, wherein the ratio of the electrically non-conductive portion area to the total of the electrically conductive portion area and the electrically non-conductive portion area is about 30% or more.
Claim 5
Dependent Claim
34 words
Apparatus according to claim 3, wherein the ratio of the electrically non-conductive portion area to the total of the electrically conductive portion area and the electrically non-conductive portion area is about 70% or less.
Claim 6
Dependent Claim
19 words
Apparatus according to claim 1, wherein the electric non-conductive portion comprising at least one opening in the shielding layer.
Claim 7
Dependent Claim
117 words
A plasma discharge apparatus usable with a source of R.F. power, the apparatus comprising: a chamber in which plasma discharge is to be produced; a loop coil formed from an antenna electric conductor and which can be operatively connected to the source of R.F. power, said coil being positioned to produce a high frequency electric field in the chamber; an electric shield including at least one strip of a non-magnetic electrically conductive material, said strip being electrically connected to the antenna so as to comprise a return circuit, wherein the strip is wound toroidally around the antenna leaving a spiral gap between neighboring turns of the strip; and means for fixing the electric potential of said shield.
Claim 8
Dependent Claim
117 words
A plasma discharge apparatus usable with a source of R.F. power, the apparatus comprising: a chamber in which plasma discharge is to be produced; a loop coil formed from an antenna electric conductor and which can be operatively connected to the source of R.F. power, said coil being positioned to produce a high frequency electric field in the chamber; an electric shield including at least one strip of a non-magnetic electrically conductive material, said strip being electrically connected to the antenna so as to comprise a return circuit, wherein the strip is wound toroidally around the antenna leaving a spiral gap between neighboring turns of the strip; and means for fixing the electric potential of said shield.
Claim 9
Dependent Claim
11 words
Apparatus according to claim 6, wherein the electric shield is grounded.
Claim 10
Dependent Claim
35 words
Apparatus according to claim 6, wherein the ratio of the area of said gap to the total of the area of said conductive strip and the area of the gap is about 30% or more.
Claim 11
Dependent Claim
35 words
Apparatus according to claim 6, wherein the ratio of the area of said gap to the total of the area of said conductive strip and the area of the gap is about 70% or less.
Claim 12
Dependent Claim
26 words
Apparatus according to claim 6, wherein each of said gaps between the neighboring turns of the strip is less than a Debye length of generated plasma.
Claim 13
Dependent Claim
23 words
Apparatus according to claim 6, wherein each of said gaps between the neighboring turns of the strip is about 1 mm or less.
Claim 14
Dependent Claim
42 words
Apparatus according to claim 6, wherein the toroidally wound strip comprises a conductive underlayer, and wherein the strip is further wound toroidally over the gaps to comprise a conductive overlayer, said overlayer being radially spaced from said underlayer by a separation distance.
Claim 15
Dependent Claim
22 words
Apparatus according to claim 12, wherein the separation distance of the strip is about a Debye length of generated plasma or less.
Claim 16
Dependent Claim
18 words
Apparatus according to claim 12, wherein the separation distance of the strip is about 1 mm or less.
Claim 17
Dependent Claim
42 words
Apparatus according to claim 6, wherein said loop coil antenna includes a plurality of coil turns, and wherein the strip is wound toroidally around two or more coil turns, each strip turn toroidally encompassing each of said two or more coil turns.
Claim 18
Dependent Claim
138 words
A plasma discharge apparatus usable with a source of R.F. power, the apparatus comprising: a chamber in which plasma discharge is to be produced; a loop coil antenna formed from an electric conductor and which can be operatively connected to the source of R.F. power, said coil being positioned to produce a high frequency electric field in the chamber; and a double layer electric shield including at least one strip of a non-magnetic electrically conductive material, said strip being grounded and connected to the antenna so as to comprise a return circuit, wherein the strip is wound toroidally around the coil leaving gaps between neighboring turns of the strip to comprise a conductive underlayer and further toroidally wound over the gaps to comprise a conductive overlayer, said overlayer being radially spaced from said underlayer by a separation distance.
Claim 19
Dependent Claim
138 words
A plasma discharge apparatus usable with a source of R.F. power, the apparatus comprising: a chamber in which plasma discharge is to be produced; a loop coil antenna formed from an electric conductor and which can be operatively connected to the source of R.F. power, said coil being positioned to produce a high frequency electric field in the chamber; and a double layer electric shield including at least one strip of a non-magnetic electrically conductive material, said strip being grounded and connected to the antenna so as to comprise a return circuit, wherein the strip is wound toroidally around the coil leaving gaps between neighboring turns of the strip to comprise a conductive underlayer and further toroidally wound over the gaps to comprise a conductive overlayer, said overlayer being radially spaced from said underlayer by a separation distance.
Claim 20
Dependent Claim
19 words
Apparatus according to claim 16, wherein the separation distance is about a Debye length of generated plasma or less.
Claim 21
Dependent Claim
15 words
Apparatus according to claim 16, wherein the separation distance is about 1 mm or less.
Claim 22
Dependent Claim
21 words
Apparatus according to claim 18, wherein the separation distance is about one-tenth of a Debye length of generated plasma or more.
Claim 23
Dependent Claim
15 words
Apparatus according to claim 18, wherein the separation distance is about 0.1 mm or more.
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) | 1999-10-01 | 2000-04-01 | 2000-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-10-01 | 2004-04-01 | 2004-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-10-01 | 2008-04-01 | 2008-10-01 | $7700.00 | Window Closed / Lapsed |