US4952273A
Expired / Lapsed
US
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Plasma generation in electron cyclotron resonance
Assignee: MICROSCIENCE Inc A CORP OF
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Filing: 1988-09-21
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Granted: 1990-08-28
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Expires: 2008-09-21
Abstract
Abstract Electron cyclotron resonance (ECR) is achieved in a source chamber of a size which is non-resonant with respect to propagation of the microwave power within the chamber. The microwaves are delivered into the chamber via a waveguide and window so that breakdown occurs initially only in a region in the vicinity of the window. A dielectric coupler between the waveguide and the window has a larger end and a smaller end and is filled with a dielectric material. The magnetic field generator for stimulation the electron resonance in the chamber includes a pair of conductive current carrying coils coaxial with each other and with an axis of the chamber, the coils being arranged in a Helmholtz configuration. The waveguide includes a microwave stub tuner for tuning the propagation and absorption of the microwave power in the plasma within the chamber to control the location and shape of the region in which the plasma is formed. A conduit provides a path for delivery of the plasma from one end of the chamber and is sized to be non-resonant with respect to propagation of the microwave energy. The magnetic field is controlled to cause the formation of the plasma with high absorption of microwave power occurring substantially within a columnar region centered on an axis of the chamber. The chamber has an insulative lining.
Inventors
- 👤 Oleg A. Popov
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:41
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32009; H01J37/32192; H01J37/32211; H01J37/32431; H01J37/3266; H01J37/32678; H05; H05H; H05H1/00; H05H1/02; H05H1/16; H05H1/18
Claims Analysis
Total Claims: 48
Claim 1
Independent Claim
91 words
Apparatus for generating a plasma from a gas, comprising an evacuated chamber for receiving a volume of the gas, a microwave source connected to deliver microwave power, via a window of the chamber, and a magnetic field generator for establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power, said evacuated chamber being of a dimension that is non-resonant with respect to propagation of the microwave power within the chamber in the absence of the plasma.
Claim 2
Dependent Claim
91 words
Apparatus for generating a plasma from a gas, comprising an evacuated chamber for receiving a volume of the gas, a microwave source connected to deliver microwave power, via a window of the chamber, and a magnetic field generator for establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power, said evacuated chamber being of a dimension that is non-resonant with respect to propagation of the microwave power within the chamber in the absence of the plasma.
Claim 3
Dependent Claim
118 words
Apparatus for generating a plasma from a gas, comprising an evacuated chamber for receiving a volume of the gas, a microwave source connected by a waveguide to the chamber to deliver microwave power, via a window of the chamber, to initiate breakdown a magnetic field generator for establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, the configuration of the waveguide and window being chosen with respect to a mode of propagation of the microwave power so that delivery of microwave power into the chamber and the breakdown both occur initially only in a region in the vicinity of the window.
Claim 4
Dependent Claim
118 words
Apparatus for generating a plasma from a gas, comprising an evacuated chamber for receiving a volume of the gas, a microwave source connected by a waveguide to the chamber to deliver microwave power, via a window of the chamber, to initiate breakdown a magnetic field generator for establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, the configuration of the waveguide and window being chosen with respect to a mode of propagation of the microwave power so that delivery of microwave power into the chamber and the breakdown both occur initially only in a region in the vicinity of the window.
Claim 5
Dependent Claim
37 words
The apparatus of claim 2 wherein the transmitted power (P t =P inc -P ref , where P inc is the incident power and P ref is the reflected power) in initial breakdown is below 40 watts.
Claim 6
Dependent Claim
157 words
Apparatus for generating a plasma from a gas, comprising an evacuated chamber for receiving a volume of gas, a microwave source to deliver microwave power, via a waveguide to a window of the chamber, the waveguide being of larger cross-section than the chamber, a magnetic field generator for establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, and a dielectric coupler, between the waveguide and the window, the coupler having a larger end for coupling to the waveguide, a smaller end for coupling to the window, and a dielectric material between the two ends, the ratio of the dimensions of the larger end, Φ 0 to the smaller end, Φ e being √e, where e is the dielectric constant of the dielectric material, every cross-sectional width of the larger end being larger than any cross-sectional width of the smaller end.
Claim 7
Dependent Claim
157 words
Apparatus for generating a plasma from a gas, comprising an evacuated chamber for receiving a volume of gas, a microwave source to deliver microwave power, via a waveguide to a window of the chamber, the waveguide being of larger cross-section than the chamber, a magnetic field generator for establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, and a dielectric coupler, between the waveguide and the window, the coupler having a larger end for coupling to the waveguide, a smaller end for coupling to the window, and a dielectric material between the two ends, the ratio of the dimensions of the larger end, Φ 0 to the smaller end, Φ e being √e, where e is the dielectric constant of the dielectric material, every cross-sectional width of the larger end being larger than any cross-sectional width of the smaller end.
Claim 8
Dependent Claim
16 words
The apparatus of claim 4 in which the dielectric coupler is not within an evacuated region.
Claim 9
Dependent Claim
25 words
The apparatus of claim 4 in which the length of the dielectric coupler is exactly an integral number of half wavelengths of the microwave power.
Claim 10
Dependent Claim
38 words
The apparatus of claim 4 in which the window is supported in a flange and the magnetic field generator surrounds the chamber and is larger than the flange but smaller than the large end of the dielectric coupler.
Claim 11
Dependent Claim
15 words
The apparatus of claim 4 in which the dielectric coupler includes a metal outer wall.
Claim 12
Dependent Claim
119 words
Apparatus for generating a plasma from a gas, comprising an evacuated chamber for receiving a volume of the gas, a microwave source connected to deliver microwave energy to the chamber, a magnetic field generator for establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power, the magnetic field generator comprising a pair of conductive current carrying coils coaxial with each other and with an axis of the chamber, the coils being spaced apart in a Helmholtz configuration, said evacuated chamber being of a dimension that is non-resonant with respect to propagation of the microwave power within the chamber in the absence of the plasma.
Claim 13
Dependent Claim
119 words
Apparatus for generating a plasma from a gas, comprising an evacuated chamber for receiving a volume of the gas, a microwave source connected to deliver microwave energy to the chamber, a magnetic field generator for establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power, the magnetic field generator comprising a pair of conductive current carrying coils coaxial with each other and with an axis of the chamber, the coils being spaced apart in a Helmholtz configuration, said evacuated chamber being of a dimension that is non-resonant with respect to propagation of the microwave power within the chamber in the absence of the plasma.
Claim 14
Dependent Claim
109 words
Apparatus for generating a plasma from a gas, comprising an evacuated chamber for receiving a volume of the gas, a microwave source connected by a waveguide to the chamber to deliver microwave energy, via a window of the chamber, a magnetic field generator for establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power, the waveguide including a microwave multiple stub tuner for tuning the propagation of electromagnetic waves from the microwave source to the plasma within the chamber to control the location and shape of the region in which the plasma is formed.
Claim 15
Dependent Claim
109 words
Apparatus for generating a plasma from a gas, comprising an evacuated chamber for receiving a volume of the gas, a microwave source connected by a waveguide to the chamber to deliver microwave energy, via a window of the chamber, a magnetic field generator for establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power, the waveguide including a microwave multiple stub tuner for tuning the propagation of electromagnetic waves from the microwave source to the plasma within the chamber to control the location and shape of the region in which the plasma is formed.
Claim 16
Dependent Claim
85 words
Apparatus for generating a plasma from a gas, comprising an evacuated chamber for receiving a volume of the gas, a microwave source connected to deliver microwave energy to the chamber, a magnetic field generator for establishing, within the chamber, a magnetic field to cause motion of the electrons to be resonant with a frequency of the microwave power, and a conduit which delivers the plasma from an end of the chamber and is sized to be non-resonant with respect to propagation of the microwave power.
Claim 17
Dependent Claim
85 words
Apparatus for generating a plasma from a gas, comprising an evacuated chamber for receiving a volume of the gas, a microwave source connected to deliver microwave energy to the chamber, a magnetic field generator for establishing, within the chamber, a magnetic field to cause motion of the electrons to be resonant with a frequency of the microwave power, and a conduit which delivers the plasma from an end of the chamber and is sized to be non-resonant with respect to propagation of the microwave power.
Claim 18
Dependent Claim
14 words
The apparatus of claim 11 in which the conduit is shorter than its width.
Claim 19
Dependent Claim
14 words
The apparatus of claim 11 in which the conduit is longer than its width.
Claim 20
Dependent Claim
21 words
The apparatus of claim 11 further comprising a second, separate magnetic field generator for generating a magnetic field within the conduit.
Claim 21
Dependent Claim
80 words
Apparatus for generating a plasma from a gas, comprising introducing the gas into an evacuated chamber, delivering microwave power, via a window of the chamber, establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, and causing the evacuated chamber to have a dimension that is non-resonant with respect to propagation of the microwave power within the chamber in the absence of the plasma.
Claim 22
Dependent Claim
80 words
Apparatus for generating a plasma from a gas, comprising introducing the gas into an evacuated chamber, delivering microwave power, via a window of the chamber, establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, and causing the evacuated chamber to have a dimension that is non-resonant with respect to propagation of the microwave power within the chamber in the absence of the plasma.
Claim 23
Independent Claim
97 words
A method for generating a plasma from a gas, comprising introducing the gas into an evacuated chamber, delivering microwave power through a waveguide and via a window, establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, the configuration of the waveguide and window being chosen with respect to a mode of propagation of the microwave power so that delivery of microwave power into the chamber and breakdown both occur initially only in a region in the vicinity of the window.
Claim 24
Independent Claim
97 words
A method for generating a plasma from a gas, comprising introducing the gas into an evacuated chamber, delivering microwave power through a waveguide and via a window, establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, the configuration of the waveguide and window being chosen with respect to a mode of propagation of the microwave power so that delivery of microwave power into the chamber and breakdown both occur initially only in a region in the vicinity of the window.
Claim 25
Independent Claim
82 words
A method for generating a plasma from a gas, comprising introducing the gas into an evacuated chamber, delivering microwave power to the chamber, establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power, and providing, as the magnetic field generator, a pair of conductive current carrying rings coaxial with each other and with an axis of the chamber, the rings being spaced apart in a Helmholtz configuration.
Claim 26
Independent Claim
82 words
A method for generating a plasma from a gas, comprising introducing the gas into an evacuated chamber, delivering microwave power to the chamber, establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power, and providing, as the magnetic field generator, a pair of conductive current carrying rings coaxial with each other and with an axis of the chamber, the rings being spaced apart in a Helmholtz configuration.
Claim 27
Independent Claim
78 words
A method for generating a plasma from a gas, comprising introducing the gas into an evacuated chamber, delivering microwave power through a waveguide and via a window, establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, and tuning a multiple stub microwave tuner in the waveguide to control the location and shape of the region in which the plasma is formed.
Claim 28
Independent Claim
78 words
A method for generating a plasma from a gas, comprising introducing the gas into an evacuated chamber, delivering microwave power through a waveguide and via a window, establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, and tuning a multiple stub microwave tuner in the waveguide to control the location and shape of the region in which the plasma is formed.
Claim 29
Dependent Claim
26 words
The method of claim 18 in which the microwave tuner is tuned to achieve a cylindrical plasma formation region centered on an axis of the chamber.
Claim 30
Dependent Claim
26 words
The method of claim 18 in which the microwave tuner is tuned to achieve a ring-shaped plasma formation region, centered on an axis of the chamber.
Claim 31
Dependent Claim
26 words
The method of claim 18 in which the microwave tuner is tuned to achieve a generally continuous plasma formation region across the width of the chamber.
Claim 32
Dependent Claim
26 words
The method of claim 18 in which the magnetic field generator is controlled to establish a predetermined magnetic field strength in the vicinity of the window.
Claim 33
Dependent Claim
82 words
Apparatus for generating a plasma from a gas, comprising introducing the gas into an evacuated chamber, delivering microwave power to the chamber, establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power, and providing a conduit to form a path for delivery of the plasma from an end of the chamber said conduit being sized to have arbitrary dimensions with respect to propagation of the microwave power.
Claim 34
Dependent Claim
82 words
Apparatus for generating a plasma from a gas, comprising introducing the gas into an evacuated chamber, delivering microwave power to the chamber, establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power, and providing a conduit to form a path for delivery of the plasma from an end of the chamber said conduit being sized to have arbitrary dimensions with respect to propagation of the microwave power.
Claim 35
Dependent Claim
31 words
The method of claim 23 in which a microwave tuner associated with the delivery of microwave power to the chamber is adjusted to cause the formation of plasma within the conduit.
Claim 36
Dependent Claim
39 words
The method of claim 23 for delivering the plasma to a work surface in which the distance of the work surface to the end of the conduit is controllably adjusted to achieve a desired plasma density at the surface.
Claim 37
Dependent Claim
24 words
The apparatus of claim 1, 2, 9, 10, or 11 in which the magnetic field at the location of initial breakdown is 875 Gauss.
Claim 38
Dependent Claim
108 words
Apparatus for generating a plasma from a gas for delivery to a work surface comprising an evacuated chamber for receiving a volume of the gas and delivering the plasma to the work surface, a microwave source connected to deliver microwave power to the chamber, and magnetic field generator for establishing within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, the chamber having an insulative lining whereby the plasma may be delivered free of current, enabling the work surface to be held at ground potential or floating potential without disturbing the plasma characteristics.
Claim 39
Dependent Claim
108 words
Apparatus for generating a plasma from a gas for delivery to a work surface comprising an evacuated chamber for receiving a volume of the gas and delivering the plasma to the work surface, a microwave source connected to deliver microwave power to the chamber, and magnetic field generator for establishing within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, the chamber having an insulative lining whereby the plasma may be delivered free of current, enabling the work surface to be held at ground potential or floating potential without disturbing the plasma characteristics.
Claim 40
Dependent Claim
24 words
The apparatus of claim 1, 2, 9, 10, or 11 in which the magnetic field generator is movable along the length of the chamber.
Claim 41
Dependent Claim
32 words
The apparatus of claim 1, 2, 9, 10, or 11 in which the magnetic field generator is tunable to provide selectively uniform or gradient magnetic fields along the length of the chamber.
Claim 42
Independent Claim
20 words
The apparatus of claims 1, 2, 9, 10, or 11 in which the chamber is smaller than 2" in diameter.
Claim 43
Dependent Claim
86 words
Apparatus for generating a plasma from a gas, comprising introducing the gas into an evacuated chamber, delivering microwave power to the chamber, establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, whereby a plasma is formed, and controlling the magnetic field to cause the formation of the plasma with high absorption of microwave power within selectably either a columnar or ring-shaped region centered on an axis of the chamber.
Claim 44
Dependent Claim
86 words
Apparatus for generating a plasma from a gas, comprising introducing the gas into an evacuated chamber, delivering microwave power to the chamber, establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, whereby a plasma is formed, and controlling the magnetic field to cause the formation of the plasma with high absorption of microwave power within selectably either a columnar or ring-shaped region centered on an axis of the chamber.
Claim 45
Dependent Claim
33 words
The apparatus of claim 1 wherein said evacuated chamber is of a dimension smaller than the cutoff dimensions for propagation of the microwave power within the chamber in the absence of the plasma.
Claim 46
Dependent Claim
33 words
The method of claim 15 wherein the dimension of the evacuated chamber is smaller than the cutoff dimensions for propagation of the microwave power within the chamber in the absence of the plasma.
Claim 47
Dependent Claim
36 words
The apparatus of claim 4, 10, or 11 wherein said evacuated chamber is of a dimension that is non-resonant with respect to propagation of the microwave power within the chamber in the absence of the plasma.
Claim 48
Dependent Claim
33 words
The apparatus of claim 34 wherein said evacuated chamber is of a dimension smaller than the cutoff dimensions for propagation of the microwave power within the chamber in the absence of the plasma.
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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) | 1993-08-27 | 1994-02-26 | 1994-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-27 | 1998-02-26 | 1998-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-27 | 2002-02-26 | 2002-08-28 | $7700.00 | Window Closed / Lapsed |