US4041353A
Expired / Lapsed
US
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Glow discharge method and apparatus
Assignee: Dart Industries Inc
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Filing: 1974-12-23
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Granted: 1977-08-09
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Expires: 1994-12-23
Abstract
Abstract A method and apparatus for providing a completely closed plasma trap in an r.f. type glow discharge system to enable enhanced sputtering from a pair of electrodes so that substrates may be suitably coated. The electrode pairs may be post type, hollow or planar, in various shapes with and without end wings. All configurations utilize a cooperating magnetic field, provided by field coils external or internal to the electrodes, the magnetic field being shaped to define with the electrodes at least one plasma containing trap having axial symmetry imposed by the magnetic field and/or the electrode structure. The trap may be defined by the pair of electrodes acting in concert with each other and the magnetic field, one or more traps may be defined separately by each electrode and the magnetic field, or both types of traps may exist simultaneously in a hybrid situation. Means are also disclosed for mounting, centering, cooling, assembling and making electrical contact with various of the electrode structures. Means are further disclosed for protecting various structural elements from undesired exposure to plasma, preventing conductive plating of insulators, due to undesired deposition of target material, and shielding the entire glow discharge system to prevent undesired r.f. radiation leakage to the surrounding environment.
Inventors
- 👤 Alan S. Penfold
- 👤 John A. Thornton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:40
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/34; H01J37/3402
Claims Analysis
Total Claims: 60
Claim 1
Independent Claim
63 words
A method of generating a glow discharge, comprising the steps of: supporting an electrode assembly within a working gas environment; applying electrical voltage to said electrode assembly; and forming a magnetic field which defines, together with said electrode assembly, a plurality of traps for containing substantially all electrons emitted from said electrode assembly and having sufficient energy to further ionize said working gas.
Claim 2
Independent Claim
63 words
A method of generating a glow discharge, comprising the steps of: supporting an electrode assembly within a working gas environment; applying electrical voltage to said electrode assembly; and forming a magnetic field which defines, together with said electrode assembly, a plurality of traps for containing substantially all electrons emitted from said electrode assembly and having sufficient energy to further ionize said working gas.
Claim 3
Dependent Claim
24 words
A method as set forth in claim 1, and further including: maintaining said working gas environment at a pressure of 1 micron or less.
Claim 4
Dependent Claim
17 words
A method as set forth in claim 1, wherein said electrode assembly comprises a pair of electrodes.
Claim 5
Dependent Claim
15 words
A method as set forth in claim 1, wherein said voltage is an r.f. voltage.
Claim 6
Dependent Claim
19 words
A method as set forth in claim 1, wherein said traps have axial symmetry about an axis of rotation.
Claim 7
Dependent Claim
19 words
A method as set forth in claim 1, wherein said magnetic field is formed from within said electrode assembly.
Claim 8
Dependent Claim
22 words
A method as set forth in claim 1, wherein said magnetic field is formed from a location external to said electrode assembly.
Claim 9
Dependent Claim
22 words
A method as set forth in claim 1, wherein said electrode assembly includes a sputtering surface comprised of an electrically conductive material.
Claim 10
Dependent Claim
22 words
A method as set forth in claim 1, wherein said electrode assembly includes a sputtering surface comprised of an electrically insulating material.
Claim 11
Dependent Claim
13 words
A method as set forth in claim 3, wherein said electrodes are coaxial.
Claim 12
Dependent Claim
27 words
A method as set forth in claim 3, wherein said electrodes are in a post type configuration with the glow discharge being generated externally of said electrodes.
Claim 13
Dependent Claim
19 words
A method as set forth in claim 3, wherein each of said electrodes defines a conical surface of revolution.
Claim 14
Dependent Claim
23 words
A method as set forth in claim 3, wherein said magnetic field is formed to define separate traps with each of said electrodes.
Claim 15
Dependent Claim
23 words
A method as set forth in claim 4, and further including: electrically shielding said electrode assembly and working gas environment against r.f. leakage.
Claim 16
Dependent Claim
18 words
A method as set forth in claim 5, wherein said axial symmetry is defined by said magnetic field.
Claim 17
Dependent Claim
18 words
A method as set forth in claim 5, wherein said axial symmetry is defined by said electrode assembly.
Claim 18
Dependent Claim
23 words
A method as set forth in claim 5, wherein said axial symmetry is defined by both said magnetic field and said electrode assembly.
Claim 19
Independent Claim
68 words
A method of sputtering material from a pair of target electrodes onto a substrate, comprising the steps of: disposing said electrodes within a substantially low pressure gaseous environment; forming a magnetic field which defines, together with said electrodes, a plurality of traps for containing substantially all electrons emitted from said electrodes and having sufficient energy to create additional ions; and applying an r.f. voltage across said target electrodes.
Claim 20
Independent Claim
68 words
A method of sputtering material from a pair of target electrodes onto a substrate, comprising the steps of: disposing said electrodes within a substantially low pressure gaseous environment; forming a magnetic field which defines, together with said electrodes, a plurality of traps for containing substantially all electrons emitted from said electrodes and having sufficient energy to create additional ions; and applying an r.f. voltage across said target electrodes.
Claim 21
Dependent Claim
23 words
A method as set forth in claim 18, wherein said magnetic field is formed to define separate traps with each of said electrodes.
Claim 22
Dependent Claim
21 words
A method as set forth in claim 18, and further including: electrically shielding said electrodes and gaseous environment against r.f. leakage.
Claim 23
Dependent Claim
24 words
A method as set forth in claim 18, wherein said low pressure gaseous environment is maintained at a pressure of 1 micron or less.
Claim 24
Dependent Claim
19 words
A method as set forth in claim 18, wherein said traps have axial symmetry about an axis of rotation.
Claim 25
Dependent Claim
27 words
A method as set forth in claim 18, wherein said traps have axial symmetry about an axis of rotation, said symmetry being defined by said magnetic field.
Claim 26
Dependent Claim
27 words
A method as set forth in claim 18, wherein said traps have axial symmetry about an axis of rotation, said symmetry being defined by said target electrodes.
Claim 27
Dependent Claim
28 words
A method as set forth in claim 18, wherein said traps have axial symmetry about an axis of rotation defined by both said magnetic fields and said electrodes.
Claim 28
Dependent Claim
68 words
In an r.f. glow discharge system for sputtering, the combination comprising: an electrode assembly disposed within a gaseous environment; means for applying an r.f. voltage to electrodes in said electrode assembly; and means for forming a magnetic field which defines with said electrode assembly a plurality of completely closed traps for containing substantially all electrons emitted from said electrode assembly and having sufficient energy to create additional ions.
Claim 29
Dependent Claim
68 words
In an r.f. glow discharge system for sputtering, the combination comprising: an electrode assembly disposed within a gaseous environment; means for applying an r.f. voltage to electrodes in said electrode assembly; and means for forming a magnetic field which defines with said electrode assembly a plurality of completely closed traps for containing substantially all electrons emitted from said electrode assembly and having sufficient energy to create additional ions.
Claim 30
Dependent Claim
26 words
A combination as set forth in claim 26, wherein said electrode assembly is disposed in a gaseous environment at a pressure of one micron or less.
Claim 31
Dependent Claim
17 words
A combination as set forth in claim 26, wherein said electrode assembly comprises a pair of electrodes.
Claim 32
Dependent Claim
19 words
A combination as set forth in claim 26, wherein said traps have axial symmetry about an axis of rotation.
Claim 33
Dependent Claim
25 words
A combination as set forth in claim 26, and further including: means for electrically shielding said electrode assembly and said glow discharge against r.f. leakage.
Claim 34
Dependent Claim
22 words
A combination as set forth in claim 26, wherein said means for forming a magnetic field is located within said electrode assembly.
Claim 35
Dependent Claim
22 words
A combination as set forth in claim 26, wherein said means for forming said magnetic field is external of said electrode assembly.
Claim 36
Dependent Claim
27 words
A combination as set forth in claim 28, wherein said electrodes are in a post type configuration with the glow discharge being generated externally of said electrodes.
Claim 37
Dependent Claim
22 words
A combination as set forth in claim 28, wherein said magnetic field defines a single separate trap with each of said electrodes.
Claim 38
Dependent Claim
22 words
A combination as set forth in claim 28, wherein each of said electrodes includes a sputtering surface comprising an electrically conductive material.
Claim 39
Dependent Claim
22 words
A combination as set forth in claim 28, wherein each of said electrodes includes a sputtering surface comprising an electrically insulating material.
Claim 40
Dependent Claim
83 words
Glow discharge apparatus for sputtering, comprising: a pair of electrodes; mounting means for supporting said electrodes in close, spaced apart relationship in a low pressure working gas environment; power supply means for supplying an electrical voltage across said pair of electrodes; and magnetic field means for forming a magnetic field which defines with said electrodes at least one completely closed trap over each electrode for containing substantially all electrons emitted from said electrodes and having sufficient energy to further ionize said working gas.
Claim 41
Dependent Claim
83 words
Glow discharge apparatus for sputtering, comprising: a pair of electrodes; mounting means for supporting said electrodes in close, spaced apart relationship in a low pressure working gas environment; power supply means for supplying an electrical voltage across said pair of electrodes; and magnetic field means for forming a magnetic field which defines with said electrodes at least one completely closed trap over each electrode for containing substantially all electrons emitted from said electrodes and having sufficient energy to further ionize said working gas.
Claim 42
Dependent Claim
20 words
Apparatus as set forth in claim 37, wherein said working gas is at a pressure of 1 micron or less.
Claim 43
Dependent Claim
21 words
Apparatus as set forth in claim 37, wherein said electrical voltage applied across said pair of electrodes is an r.f. voltage.
Claim 44
Dependent Claim
18 words
Apparatus as set forth in claim 37, wherein said traps have axial symmetry about an axis of rotation.
Claim 45
Dependent Claim
20 words
Apparatus as set forth in claim 37, wherein said mounting means supports said electrodes in coaxial relationship to each other.
Claim 46
Dependent Claim
25 words
Apparatus as set forth in claim 37, wherein said electrodes are in a post-type configuration with said glow discharge being generated externally of said electrodes.
Claim 47
Dependent Claim
18 words
Apparatus as set forth in claim 37, wherein each of said electrodes defines a conical surface of revolution.
Claim 48
Dependent Claim
21 words
Apparatus as set forth in claim 37, wherein said magnetic field defines a single separate trap with each of said electrodes.
Claim 49
Dependent Claim
22 words
Apparatus as set forth in claim 37, wherein at least a portion of said magnetic field means is located within said electrodes.
Claim 50
Dependent Claim
23 words
Apparatus as set forth in claim 37, wherein at least a portion of said magnetic field means is located externally of said electrodes.
Claim 51
Dependent Claim
22 words
Apparatus as set forth in claim 37, and further including: a vacuum chamber containing said pair of electrodes and said mounting means.
Claim 52
Dependent Claim
17 words
Apparatus as set forth in claim 37, and further including: electrical insulator means supported between said electrodes.
Claim 53
Dependent Claim
17 words
Apparatus as set forth in claim 40, wherein said axial symmetry is defined by said magnetic field.
Claim 54
Dependent Claim
16 words
Apparatus as set forth in claim 40, wherein said axial symmetry is defined by said electrodes.
Claim 55
Dependent Claim
21 words
Apparatus as set forth in claim 40, wherein said axial symmetry is defined by both said magnetic field and said electrodes.
Claim 56
Dependent Claim
18 words
Apparatus as set forth in claim 42, wherein each of said electrodes defines a conical surface of revolution.
Claim 57
Dependent Claim
21 words
Apparatus as set forth in claim 42, wherein said electrodes are coaxial and include outwardly extending wings at remote opposite ends.
Claim 58
Dependent Claim
23 words
Apparatus as set forth in claim 47, wherein said magnetic field means comprises: a plurality of field windings mounted outside said vacuum chamber.
Claim 59
Dependent Claim
22 words
Apparatus as set forth in claim 52, wherein each electrode has a frustum end confronting the frustum end of the other electrode.
Claim 60
Dependent Claim
19 words
Apparatus as set forth in claim 55, wherein each electrode has an outwardly extending end wing at its base.
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) | 1980-08-08 | 1981-02-07 | 1981-08-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-08 | 1985-02-07 | 1985-08-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-08 | 1989-02-07 | 1989-08-09 | $7700.00 | Window Closed / Lapsed |