US4866346A
Expired / Lapsed
US
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Microwave plasma generator
Assignee: MKS Instruments Inc
•
Filing: 1987-06-22
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Granted: 1989-09-12
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Expires: 2007-06-22
Abstract
Abstract A microwave plasma generator for producing an axisymmetric plasma, having a waveguide apparatus, means for introducing a microwave source into the waveguide apparatus, and means for generating a circular axisymmetric microwave field from the microwave source. There are means for tuning the field to match the impedance of a plasma load. Further included is a vacuum chamber for containing a gas to be ionized to form the plasma, means for introducing this gas into the vacuum chamber, and means for coupling the microwave field to the vacuum chamber to form the plasma.
Inventors
- 👤 Marcel P. J. Gaudreau
- 👤 Donald K. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:52
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32009; H01J37/32192; H01J37/32211; H01J37/32229; H01J37/32247; H01J37/32256; H05; H05H; H05H1/00; H05H1/24; H05H1/46
Claims Analysis
Total Claims: 52
Claim 1
Independent Claim
98 words
A microwave plasma generator for producing an axisymmetric plasma, comprising: a waveguide apparatus; means for introducing a microwave source into said waveguide apparatus; means for generating a circular axisymmetric microwave field from said source; means for tuning said field to match the impedance of a plasma load; a vacuum chamber, interconnected to said waveguide apparatus, for containing a gas to be ionized to form said plasma; means for introducing said gas into said vacuum chamber; and means for coupling said field to said vacuum chamber to form, in response to said circular axisymmetric microwave field, said axisymmetric plasma.
Claim 2
Dependent Claim
98 words
A microwave plasma generator for producing an axisymmetric plasma, comprising: a waveguide apparatus; means for introducing a microwave source into said waveguide apparatus; means for generating a circular axisymmetric microwave field from said source; means for tuning said field to match the impedance of a plasma load; a vacuum chamber, interconnected to said waveguide apparatus, for containing a gas to be ionized to form said plasma; means for introducing said gas into said vacuum chamber; and means for coupling said field to said vacuum chamber to form, in response to said circular axisymmetric microwave field, said axisymmetric plasma.
Claim 3
Dependent Claim
27 words
The microwave plasma generator of claim 1 in which said means for tuning includes adjustment means for matching the resistive and reactive impedance of a plasma load.
Claim 4
Dependent Claim
29 words
The microwave plasma generator of claim 1 in which the pressure of said gas to be ionized in said vacuum chamber is between 10 -7 and 10 3 Torr.
Claim 5
Dependent Claim
20 words
The microwave plasma generator of claim 1 in which said vacuum chamber includes a substrate for interacting with said plasma.
Claim 6
Dependent Claim
14 words
The microwave plasma generator of claim 4 further including means for heating said substrate.
Claim 7
Dependent Claim
14 words
The microwave plasma generator of claim 4 further including means for cooling said substrate.
Claim 8
Dependent Claim
15 words
The microwave plasma generator of claim 1 further including means for heating said vacuum chamber.
Claim 9
Dependent Claim
15 words
The microwave plasma generator of claim 1 further including means for cooling said vacuum chamber.
Claim 10
Dependent Claim
19 words
The microwave plasma generator of claim 3 further including means for keeping the pressure of said gas relatively constant.
Claim 11
Dependent Claim
28 words
The microwave plasma generator of claim 1 in which said field includes a transverse magnetic mode with no angular dependence and an integral number of radial mode nodes.
Claim 12
Dependent Claim
25 words
The microwave plasma generator of claim 2 in which said adjustment means includes a repeatably adjustable probe and a repeatably adjustable rectangular shorting plunger choke.
Claim 13
Dependent Claim
23 words
The microwave plasma generator of claim 11 in which said probe includes means for indicating the position of said probe in said waveguide.
Claim 14
Dependent Claim
23 words
The microwave plasma generator of claim 11 in which said choke includes means for indicating the position of said choke in said waveguide.
Claim 15
Dependent Claim
19 words
The microwave plasma generator of claim 1 further including at least one magnet assembly disposed around said vacuum chamber.
Claim 16
Dependent Claim
21 words
The microwave plasma generator of claim 1 in which the frequency of said microwave source is between 0.5 and 15 GHz.
Claim 17
Dependent Claim
19 words
The microwave plasma generator of claim 1 in which the frequency of said microwave source is approximately 2.45 GHz.
Claim 18
Dependent Claim
23 words
The microwave plasma generator of claim 1 further including means for generating an electric field in said vacuum chamber to accelerate said plasma.
Claim 19
Dependent Claim
122 words
A tunable microwave waveguide apparatus for producing a single mode circular axisymmetric microwave field for axisymmetric plasma production, comprising: an input waveguide with a rectangular cross section; means for introducing a microwave source into said input waveguide; an output waveguide with a circular cross section; means for connecting said input waveguide to said output waveguide; an adjustable probe assembly for generating said microwave field in said output waveguide from said source and substantially matching the resistive impedance of a plasma load; an adjustable plunger assembly disposed in said input waveguide for substantially matching the reactive impedance of said load; and means for coaxially coupling said output waveguide to a vacuum chamber containing a gas to be ionized to form said axisymmetric plasma.
Claim 20
Dependent Claim
122 words
A tunable microwave waveguide apparatus for producing a single mode circular axisymmetric microwave field for axisymmetric plasma production, comprising: an input waveguide with a rectangular cross section; means for introducing a microwave source into said input waveguide; an output waveguide with a circular cross section; means for connecting said input waveguide to said output waveguide; an adjustable probe assembly for generating said microwave field in said output waveguide from said source and substantially matching the resistive impedance of a plasma load; an adjustable plunger assembly disposed in said input waveguide for substantially matching the reactive impedance of said load; and means for coaxially coupling said output waveguide to a vacuum chamber containing a gas to be ionized to form said axisymmetric plasma.
Claim 21
Dependent Claim
37 words
The tunable microwave waveguide apparatus of claim 18 in which said probe assembly includes a repeatably axially adjustable conductive rod passing through an opening in said input waveguide and transversely therethrough and coaxially into said output waveguide.
Claim 22
Dependent Claim
45 words
The tunable microwave waveguide apparatus of claim 19 in which said probe assembly includes a probe tube communicating with said opening and an annular probe choke inside of and connected to said probe tube having a central opening for allowing said rod to pass therethrough.
Claim 23
Dependent Claim
20 words
The tunable microwave waveguide apparatus of claim 20 in which said rod passes through the center of said input waveguide.
Claim 24
Dependent Claim
21 words
The tunable microwave waveguide apparatus of claim 20 in which said rod passes through said input waveguide at an off-center position.
Claim 25
Dependent Claim
28 words
The tunable microwave waveguide apparatus of claim 20 in which said rod includes means for indicating the position of the end of said rod in said output waveguide.
Claim 26
Dependent Claim
30 words
The tunable microwave waveguide apparatus of claim 18 in which said plunger includes a repeatably axially adjustable waveguide stub with a rectangular cross section disposed coaxially within said input waveguide.
Claim 27
Dependent Claim
23 words
The tunable microwave waveguide apparatus of claim 24 in which said plunger assembly includes means for shorting said stub to said input waveguide.
Claim 28
Dependent Claim
29 words
The tunable microwave waveguide apparatus of claim 25 in which said plunger assembly includes means for indicating the position of the end of said stub in said input waveguide.
Claim 29
Dependent Claim
25 words
The tunable microwave waveguide apparatus of claim 18 in which said plunger assembly includes a repeatably axially adjustable shorting plunger disposed in said input waveguide.
Claim 30
Dependent Claim
29 words
The tunable microwave waveguide apparatus of claim 27 in which said plunger assembly includes means for indicating the position of the end of said plunger in said input waveguide.
Claim 31
Dependent Claim
20 words
The tunable microwave waveguide apparatus of claim 20 in which said probe choke is approximately one quarter free-space wavelength long.
Claim 32
Dependent Claim
20 words
The tunable microwave waveguide apparatus of claim 24 in which said stub is approximately one quarter input waveguide wavelength long.
Claim 33
Dependent Claim
19 words
The tunable microwave waveguide apparatus of claim 18 in which the frequency of said source is approximately 2.45 GHz.
Claim 34
Dependent Claim
29 words
The tunable microwave waveguide apparatus of claim 18 in which said input waveguide is small and long enough to transmit only the fundamental transverse electric mode of said source.
Claim 35
Dependent Claim
35 words
The tunable microwave waveguide apparatus of claim 18 in which the diameter of said output waveguide is small enough to transmit only one transverse magnetic mode having no angular dependence and one radial mode node.
Claim 36
Dependent Claim
21 words
The tunable microwave waveguide apparatus of claim 18 in which the length of said output waveguide is greater than its diameter.
Claim 37
Dependent Claim
29 words
The tunable microwave waveguide apparatus of claim 18 in which said field includes a transverse magnetic mode with no angular dependence and an integral number of radial mode nodes.
Claim 38
Dependent Claim
20 words
The tunable microwave waveguide apparatus of claim 33 in which the diameter of said output waveguide is approximately 12 cm.
Claim 39
Dependent Claim
20 words
The tunable microwave waveguide apparatus of claim 34 in which the length of said output waveguide is approximately 12.8 cm.
Claim 40
Dependent Claim
36 words
The tunable microwave waveguide apparatus of claim 18 in which said input waveguide is approximately 7.2 cm. wide, 3.4 cm. high, and 25.5 cm. long from its entrance flange to the center of said probe assembly.
Claim 41
Dependent Claim
21 words
The tunable microwave waveguide apparatus of claim 18 in which the diameter of said output waveguide is at least 10 cm.
Claim 42
Dependent Claim
34 words
The tunable microwave waveguide apparatus of claim 20 in which said rod extends past said choke a distance of approximately an integral multiple of one half of the free-space wavelength of said microwave source.
Claim 43
Dependent Claim
35 words
The tunable microwave waveguide apparatus of claim 18 in which the combined length of said output waveguide and said vacuum chamber is approximately an integral multiple of one-half of the wavelength of said microwave field.
Claim 44
Dependent Claim
20 words
The tunable microwave waveguide apparatus of claim 20 in which said rod passes through the center of said input waveguide.
Claim 45
Dependent Claim
27 words
The tunable microwave waveguide apparatus of claim 18 in which the diameter of said output waveguide increases along its length in the direction of said vacuum chamber.
Claim 46
Dependent Claim
96 words
A microwave plasma generator for producing an axisymmetric plasma, comprising: a repeatably tunable waveguide apparatus having an input tube with a rectangular cross section and a discharge tube with a circular cross section; means for introducing microwave energy into said input tube; means for coupling an axisymmetric microwave field to said discharge tube; a vacuum chamber for containing a gas to be ionized; means for introducing said gas into said vacuum chamber; and means for coaxially connecting said discharge tube to said vacuum chamber for producing said axisymmetric plasma in response to said axisymmetric microwave field.
Claim 47
Dependent Claim
96 words
A microwave plasma generator for producing an axisymmetric plasma, comprising: a repeatably tunable waveguide apparatus having an input tube with a rectangular cross section and a discharge tube with a circular cross section; means for introducing microwave energy into said input tube; means for coupling an axisymmetric microwave field to said discharge tube; a vacuum chamber for containing a gas to be ionized; means for introducing said gas into said vacuum chamber; and means for coaxially connecting said discharge tube to said vacuum chamber for producing said axisymmetric plasma in response to said axisymmetric microwave field.
Claim 48
Dependent Claim
24 words
The microwave plasma generator of claim 44 in which said means for coupling includes means for generating only a single mode axisymmetric microwave field.
Claim 49
Dependent Claim
95 words
A microwave plasma generator for producing an axisymmetric plasma, comprising: a waveguide apparatus; means for introducing a microwave source into said waveguide apparatus; means for generating only a single mode circular axisymmetric microwave field from said source; means for tuning said field to match the impedance of a load; a vacuum chamber for containing a gas to be ionized; means for introducing said gas into said vacuum chamber; and means for coaxially coupling said field to said vacuum chamber to form said axisymmetric plasma from said gas in response to said circular axisymmetric microwave field.
Claim 50
Dependent Claim
95 words
A microwave plasma generator for producing an axisymmetric plasma, comprising: a waveguide apparatus; means for introducing a microwave source into said waveguide apparatus; means for generating only a single mode circular axisymmetric microwave field from said source; means for tuning said field to match the impedance of a load; a vacuum chamber for containing a gas to be ionized; means for introducing said gas into said vacuum chamber; and means for coaxially coupling said field to said vacuum chamber to form said axisymmetric plasma from said gas in response to said circular axisymmetric microwave field.
Claim 51
Dependent Claim
127 words
A microwave waveguide apparatus for producing a circular axisymmetric microwave field for axisymmetric plasma production, comprising: an input waveguide with a rectangular cross section; means for introducing a microwave source into said input waveguide; an output waveguide with a circular cross section; means for connecting said input waveguide to said output waveguide; a probe assembly for generating said circular axisymmetric microwave field in said output waveguide from said source and substantially matching the resistive impedance of a plasma load; a plunger assembly disposed in said input waveguide for substantially matching the reactive impedance of said load; and means for coaxially coupling said output waveguide to a vacuum chamber containing a gas to be ionized to form said axisymmetric plasma in response to said circular axisymmetric microwave field.
Claim 52
Dependent Claim
127 words
A microwave waveguide apparatus for producing a circular axisymmetric microwave field for axisymmetric plasma production, comprising: an input waveguide with a rectangular cross section; means for introducing a microwave source into said input waveguide; an output waveguide with a circular cross section; means for connecting said input waveguide to said output waveguide; a probe assembly for generating said circular axisymmetric microwave field in said output waveguide from said source and substantially matching the resistive impedance of a plasma load; a plunger assembly disposed in said input waveguide for substantially matching the reactive impedance of said load; and means for coaxially coupling said output waveguide to a vacuum chamber containing a gas to be ionized to form said axisymmetric plasma in response to said circular axisymmetric microwave field.
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) | 1992-09-11 | 1993-03-13 | 1993-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-11 | 1997-03-13 | 1997-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-11 | 2001-03-13 | 2001-09-12 | $7700.00 | Window Closed / Lapsed |