US5648701A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrode designs for high pressure magnetically assisted inductively coupled plasmas
Assignee: University of North Carolina at Chapel Hill
•
Filing: 1994-06-28
•
Granted: 1997-07-15
•
Expires: 2014-06-28
Abstract
Abstract A plasma system is disclosed comprising a vessel suitable for containing a plasma at a pressure of at least about 100 mtorr, a plasma gas in the vessel at a pressure of at least 100 mtorr, an antenna with a substantially planar face positioned adjacent a portion of the vessel for applying an electromagnetic field to the plasma gas to thereby generate and maintain a plasma, and means for applying an external magnetic field to the plasma gas other than the field generated by the antenna, and having a component in a direction substantially perpendicular to the planar face of the antenna.
Inventors
- 👤 William M. Hooke
- 👤 Brian R. Stoner
- 👤 Steven P. Bozeman
- 👤 Roy E. Fauber
- 👤 Tobin L. Munsat
- 👤 Sean Washburn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:09
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32009; H01J37/32082; H01J37/321; H05; H05H; H05H1/00; H05H1/24; H05H1/46
Claims Analysis
Total Claims: 71
Claim 1
Independent Claim
58 words
A method of controlling an inductively coupled plasma comprising applying an external magnetic field other than the field associated with the induction field to an inductively coupled plasma while maintaining the gas pressure of the plasma high enough so that the collision frequencies of the plasma particles are substantially greater than the induction frequency applied to the plasma.
Claim 2
Independent Claim
58 words
A method of controlling an inductively coupled plasma comprising applying an external magnetic field other than the field associated with the induction field to an inductively coupled plasma while maintaining the gas pressure of the plasma high enough so that the collision frequencies of the plasma particles are substantially greater than the induction frequency applied to the plasma.
Claim 3
Dependent Claim
23 words
A method according to claim 1 wherein the step of applying an external magnetic field further comprises varying the magnetic field over time.
Claim 4
Dependent Claim
23 words
A method according to claim 1 wherein the step of applying an external magnetic field further comprises varying the magnetic field over space.
Claim 5
Dependent Claim
24 words
A method according to claim 1 wherein the step of applying an external magnetic field to the plasma comprises applying a uniform magnetic field.
Claim 6
Dependent Claim
16 words
A method according to claim 1 and further comprising the step of rotating the magnetic field.
Claim 7
Dependent Claim
16 words
A method according to claim 1 and further comprising the step of rotating the coil axis.
Claim 8
Dependent Claim
22 words
A method according to claim 1 in which the gas pressure in the plasma is between about 100 mtorr and 100 torr.
Claim 9
Dependent Claim
26 words
A method according to claim 1 wherein the step of maintaining the gas pressure high enough comprises maintaining the gas pressure at 5 Pa or greater.
Claim 10
Independent Claim
102 words
A method of controlling an inductively coupled plasma, and comprising: applying electromagnetic energy to an induction coil that surrounds a partially ionized working gas while maintaining the gas pressure of the plasma high enough so that the collision frequencies of the plasma particles are substantially greater than the induction frequency applied to the plasma to thereby define an ionization region and raise the temperature of the gas sufficiently for the gas to obtain the plasma state; and applying an external magnetic field other than the magnetic field associated with the induction field produced by the induction coil to the inductively coupled plasma.
Claim 11
Independent Claim
102 words
A method of controlling an inductively coupled plasma, and comprising: applying electromagnetic energy to an induction coil that surrounds a partially ionized working gas while maintaining the gas pressure of the plasma high enough so that the collision frequencies of the plasma particles are substantially greater than the induction frequency applied to the plasma to thereby define an ionization region and raise the temperature of the gas sufficiently for the gas to obtain the plasma state; and applying an external magnetic field other than the magnetic field associated with the induction field produced by the induction coil to the inductively coupled plasma.
Claim 12
Dependent Claim
27 words
A method according to claim 9 wherein the step of applying the external magnetic field comprises applying the field parallel to the axis of the induction coil.
Claim 13
Dependent Claim
27 words
A method according to claim 9 wherein the step of applying the external magnetic field comprises applying the field perpendicular to the axis of the induction coil.
Claim 14
Dependent Claim
27 words
A method according to claim 9 wherein the step of applying the external magnetic field comprises applying the field obliquely to the axis of the induction coil.
Claim 15
Dependent Claim
21 words
A method according to claim 9 and further comprising the steps of initiating and sustaining a plasma in the ionization region.
Claim 16
Dependent Claim
20 words
A method according to claim 9 and further comprising the step of establishing a plasma column in the ionization region.
Claim 17
Dependent Claim
20 words
A method according to claim 14 and further comprising the step of rotating the plasma column within the ionization region.
Claim 18
Dependent Claim
29 words
A method according to claim 9 wherein the step of applying the magnetic field comprises applying a magnetic field sufficient to increase the electromagnetic field penetration of the plasma.
Claim 19
Dependent Claim
36 words
A method according to claim 9 wherein the step of applying the magnetic field comprises applying a magnetic field sufficient to increase the electromagnetic field penetration of the plasma entirely to the center of the plasma.
Claim 20
Dependent Claim
36 words
A method according to claim 9 wherein the step of applying electromagnetic energy to a working gas comprises applying the energy to a working gas maintained at a pressure at least as great as atmospheric pressure.
Claim 21
Dependent Claim
55 words
An inductively coupled plasma system comprising: an ionized gas maintained at a pressure high enough so that the collision frequencies of the plasma particles are substantially greater than the induction frequency applied to the plasma; and an external magnetic field applied to said ionized gas other than the magnetic field associated with the induction field.
Claim 22
Dependent Claim
55 words
An inductively coupled plasma system comprising: an ionized gas maintained at a pressure high enough so that the collision frequencies of the plasma particles are substantially greater than the induction frequency applied to the plasma; and an external magnetic field applied to said ionized gas other than the magnetic field associated with the induction field.
Claim 23
Dependent Claim
42 words
A plasma system according to claim 19 and further comprising: a tube for containing said high pressure ionized gas; an induction coil surrounding said tube and defining an axis of said tube; and means for supplying said coil with radio frequency power.
Claim 24
Dependent Claim
31 words
A plasma system according to claim 20 wherein said tube comprises a quartz tube, said radio frequency power means comprises a radio frequency generator, and said induction coil comprises copper tubing.
Claim 25
Dependent Claim
26 words
A plasma system according to claim 20 and further comprising means for varying said magnetic field over space with respect to said axis of said tube.
Claim 26
Dependent Claim
18 words
A plasma system according to claim 20 and further comprising means for varying said magnetic field over time.
Claim 27
Dependent Claim
20 words
A plasma system according to claim 19 and further comprising means for applying a magnetic field to said ionized gas.
Claim 28
Dependent Claim
23 words
A plasma system according to claim 19 comprising an ionized gas maintained at a pressure of between about 100 mtorr and 100 torr.
Claim 29
Dependent Claim
21 words
A plasma system according to claim 19 wherein said ionized gas is maintained at a pressure of 5 Pa or greater.
Claim 30
Dependent Claim
32 words
An antenna for producing a uniform plasma at pressures of at least one torr, said antenna comprising at least one portion that forms a substantially planar configuration other than an Archimedean spiral.
Claim 31
Dependent Claim
32 words
An antenna for producing a uniform plasma at pressures of at least one torr, said antenna comprising at least one portion that forms a substantially planar configuration other than an Archimedean spiral.
Claim 32
Dependent Claim
25 words
An antenna according to claim 27 wherein the configuration of said antenna will produce a substantially uniform field at pressures of 100 mtorr or higher.
Claim 33
Dependent Claim
17 words
A plasma antenna according to claim 27 wherein said substantially planar portion comprises a single noncircular loop.
Claim 34
Dependent Claim
18 words
A plasma antenna according to claim 27 wherein said substantially planar portion comprises the configuration of FIG. 5.
Claim 35
Dependent Claim
36 words
A plasma antenna according to claim 27 wherein said substantially planar portion comprises a non-Archimedean coil in which the turns are tighter toward the center of the coil and greater toward the circumference of the coil.
Claim 36
Dependent Claim
18 words
A plasma antenna according to claim 27 wherein said substantially planar portion comprises the configuration of FIG. 6.
Claim 37
Dependent Claim
31 words
A plasma antenna according to claim 27 wherein said substantially planar portion comprises a series of substantially parallel portions connected by turns at the respective alternating ends of said parallel portions.
Claim 38
Dependent Claim
18 words
A plasma antenna according to claim 27 wherein said substantially planar portion comprises the configuration of FIG. 7.
Claim 39
Dependent Claim
16 words
A plasma antenna according to claim 27 wherein said substantially planar portion comprises multiple concentric coils.
Claim 40
Dependent Claim
18 words
A plasma antenna according to claim 27 wherein said substantially planar portion comprises the configuration of FIG. 8.
Claim 41
Dependent Claim
38 words
A plasma antenna according to claim 27 wherein said substantially planar portion comprises: a circular perimeter; a central hub coaxial with said perimeter; and a plurality of substantially linear spokes radiating from said hub to said circular perimeter.
Claim 42
Dependent Claim
18 words
A plasma antenna according to claim 27 wherein said substantially planar portion comprises the configuration of FIG. 9.
Claim 43
Dependent Claim
59 words
A plasma antenna according to claim 27 wherein said antenna comprises a longitudinally extending coil having a plurality of turns of substantially the same radius, and wherein said substantially planar portion of said antenna comprises linear portions of at least some of said turns, said linear portions being substantially parallel to one another and substantially coplanar with one another.
Claim 44
Dependent Claim
18 words
A plasma antenna according to claim 27 wherein said substantially planar portion comprises the configuration of FIG. 10.
Claim 45
Dependent Claim
64 words
A plasma antenna according to claim 27 wherein said substantially planar portion comprises: a first set of outer curved segments for completing a current loop; and a set of substantially linear center electrode-segment lengths adjacent said first curved segment set and in electrical communication with said curved segment set, for sending current in the same direction in each of segment of said center set.
Claim 46
Dependent Claim
60 words
A plasma antenna according to claim 41 and further comprising a second set of outer curved segments opposite said first set, and wherein said center electrode segments are positioned between said first and second curved segment sets, and wherein said second curved segment set is in electrical communication with said first curved segment set and with said center segment set.
Claim 47
Dependent Claim
36 words
A plasma antenna according to claim 42 wherein: said first set has N number of outer curved segments; said second set has N number of outer curved segments; and said center set has (2N+1) linear segments.
Claim 48
Dependent Claim
18 words
A plasma antenna according to claim 27 wherein said substantially planar portion comprises the configuration of FIG. 12.
Claim 49
Dependent Claim
9 words
A plasma antenna having the configuration of FIG. 11.
Claim 50
Dependent Claim
9 words
A plasma antenna having the configuration of FIG. 11.
Claim 51
Dependent Claim
21 words
A plasma antenna that comprises a spiraled electrode linearly extended along the axis of the spiral to form a frustoconical geometry.
Claim 52
Dependent Claim
21 words
A plasma antenna that comprises a spiraled electrode linearly extended along the axis of the spiral to form a frustoconical geometry.
Claim 53
Dependent Claim
15 words
A plasma antenna according to claim 46 wherein said spiraled electrode forms an Archimedean spiral.
Claim 54
Dependent Claim
15 words
A plasma antenna according to claim 46 wherein said spiraled electrode forms a non-Archimedean spiral.
Claim 55
Dependent Claim
100 words
A plasma system comprising: a vessel suitable for containing a plasma at a pressure of at least about 100 mtorr; a plasma gas in said vessel at a pressure of at least 100 mtorr; an antenna with a substantially planar face positioned adjacent a portion of said vessel for applying an electromagnetic field to said plasma gas to thereby generate and maintain a plasma; and means for applying an external magnetic field to the plasma gas other than the field generated by said antenna, and having a component in a direction substantially perpendicular to said planar face of said antenna.
Claim 56
Dependent Claim
100 words
A plasma system comprising: a vessel suitable for containing a plasma at a pressure of at least about 100 mtorr; a plasma gas in said vessel at a pressure of at least 100 mtorr; an antenna with a substantially planar face positioned adjacent a portion of said vessel for applying an electromagnetic field to said plasma gas to thereby generate and maintain a plasma; and means for applying an external magnetic field to the plasma gas other than the field generated by said antenna, and having a component in a direction substantially perpendicular to said planar face of said antenna.
Claim 57
Dependent Claim
15 words
A plasma system according to claim 49 wherein said magnetic field means comprises a magnet.
Claim 58
Dependent Claim
16 words
A plasma system according to claim 49 wherein said magnetic field means comprises a magnetic coil.
Claim 59
Dependent Claim
23 words
A plasma system according to claim 49 and further comprising a radio frequency generator for applying a radio frequency signal to said antenna.
Claim 60
Dependent Claim
14 words
A plasma system according to claim 49 wherein said vessel comprises a quartz tube.
Claim 61
Dependent Claim
21 words
A plasma system according to claim 49 wherein said vessel comprises a metal tube with a quartz window adjacent said antenna.
Claim 62
Dependent Claim
13 words
A plasma system according to claim 49 wherein said antenna comprises copper tubing.
Claim 63
Dependent Claim
17 words
A plasma system according to claim 49 and further comprising means for spatially varying said magnetic field.
Claim 64
Dependent Claim
18 words
A plasma system according to claim 49 and further comprising means for varying said magnetic field over time.
Claim 65
Independent Claim
89 words
A method of generating a uniform inductively coupled plasma at pressures of at least about 100 mtorr, said method comprising: applying an electromagnetic field from a substantially planar antenna to a plasma gas at a pressure of at least about 100 mtorr to thereby generate and maintain a plasma; and applying an external magnetic field to the plasma gas other than the field generated by the substantially planar antenna, said applied external magnetic field having a component in a direction substantially perpendicular to the planar face of said antenna.
Claim 66
Independent Claim
89 words
A method of generating a uniform inductively coupled plasma at pressures of at least about 100 mtorr, said method comprising: applying an electromagnetic field from a substantially planar antenna to a plasma gas at a pressure of at least about 100 mtorr to thereby generate and maintain a plasma; and applying an external magnetic field to the plasma gas other than the field generated by the substantially planar antenna, said applied external magnetic field having a component in a direction substantially perpendicular to the planar face of said antenna.
Claim 67
Dependent Claim
35 words
A method of generating a plasma according to claim 58 wherein the step of applying an electromagnetic field comprises applying a field with a frequency of between about 1 megahertz (MHZ) and 1 gigahertz (GHZ).
Claim 68
Dependent Claim
44 words
A method of generating a plasma according to claim 58 wherein the step of applying the electromagnetic field to the plasma gas comprises applying the electromagnetic field to a gas selected from the group consisting of argon, hydrogen, and alkane and olefin hydrocarbon gases.
Claim 69
Dependent Claim
34 words
A method of generating a plasma according to claim 58 wherein the step of applying an external magnetic field to the plasma gas comprises applying a magnetic field of at least about 100 Gauss.
Claim 70
Dependent Claim
29 words
A method according to claim 58 wherein the step of applying the magnetic field comprises applying a magnetic field sufficient to increase the electromagnetic field penetration of the plasma.
Claim 71
Dependent Claim
36 words
A method according to claim 58 wherein the step of applying the magnetic field comprises applying a magnetic field sufficient to increase the electromagnetic field penetration of the plasma entirely to the center of the plasma.
References Cited (Backward Citations)
US3084281A
Cited
US3278796A
Cited
US3442758A
Cited
US3663858A
Cited
US4058748A
Cited
US4417178A
Cited
US4438368A
Cited
US4431898A
Cited
US4431901A
Cited
US4857809A
Cited
US4727293A
Cited
US4745338A
Cited
US4849675A
Cited
US4766351A
Cited
EP0379828A2
Cited
US4948458A
Cited
EP0413282A2
Cited
EP0489407A2
Cited
EP0552491A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-07-14 | 2001-01-13 | 2001-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-07-14 | 2005-01-13 | 2005-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-07-14 | 2009-01-13 | 2009-07-15 | $7700.00 | Window Closed / Lapsed |