EP0396398A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Plasma etching apparatus with surface magnetic fields
Assignee: Wisconsin Alumni Research Foundation
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Filing: 1990-05-02
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Granted: —
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Expires: 2010-05-02
Abstract
Abstract A glow discharge etching apparatus includes a magnetic assembly 14,16,18 and 22, for creating a surface magnetic field in close proximity to the walls 30,32 of an etching chamber 12. An electrode 38 is located within the chamber for supporting the object 40 to be etched. A radio frequency signal is applied to the electrode so that it will emit secondary electrons upon bombardment by ions from an etching plasma created within the apparatus. A control plate 34 may be positioned at various locations within the apparatus to regulate the amount of electron leakage to the control plate and thereby regulate the etching process. This apparatus provides improved uniformity and directionality of etching due to a low gas pressure and the surface magnetic field.
Inventors
- 👤 Noah Hershkowitz (Nmi)
- 👤 Moo-Hyun Cho
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 18:55
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32431; H01J37/32623; H01J37/3266; H01J37/32688
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
110 words
A plasma discharge etching apparatus comprising: a chamber having electrically conductive walls within which the etching is to occur, said walls defining a boundary of said chamber; an electrode assembly within said chamber providing a source of electrons by secondary emission and a support for an object to be etched; means for introducing an ionizable gas into said chamber; means for biasing said electrode assembly to cause said electrode assembly to emit secondary electrons and create a glow discharge plasma within said chamber; and a magnet assembly for establishing a surface magnetic field adjacent to the boundary of said chamber to reflect electrons within said chamber away from the boundary.
Claim 2
Dependent Claim
110 words
A plasma discharge etching apparatus comprising: a chamber having electrically conductive walls within which the etching is to occur, said walls defining a boundary of said chamber; an electrode assembly within said chamber providing a source of electrons by secondary emission and a support for an object to be etched; means for introducing an ionizable gas into said chamber; means for biasing said electrode assembly to cause said electrode assembly to emit secondary electrons and create a glow discharge plasma within said chamber; and a magnet assembly for establishing a surface magnetic field adjacent to the boundary of said chamber to reflect electrons within said chamber away from the boundary.
Claim 3
Dependent Claim
63 words
The apparatus according to claim 1 wherein: said first electrode assembly includes first and second substantially coplanar electrodes; and said means for biasing said first electrode assembly includes a source of a radio frequency signal, and a transformer having a primary winding coupled to the source of a radio frequency signal and having a secondary winding coupled between the first and second electrodes.
Claim 4
Dependent Claim
105 words
A plasma discharge etching apparatus comprising: a chamber having electrically conductive walls within which the etching is to occur, said walls defining a boundary of said chamber; first and second substantially coplanar electrodes within said chamber, each electrode for supporting a separate object to be etched; means for introducing an ionizable gas into said chamber; means for biasing said first and second electrodes enabling the electrodes to emit secondary electrons and create a glow discharge plasma within said chamber; and a magnet assembly for establishing a magnetic field adjacent to the boundary of said chamber to reflect electrons within said chamber away from the boundary.
Claim 5
Dependent Claim
105 words
A plasma discharge etching apparatus comprising: a chamber having electrically conductive walls within which the etching is to occur, said walls defining a boundary of said chamber; first and second substantially coplanar electrodes within said chamber, each electrode for supporting a separate object to be etched; means for introducing an ionizable gas into said chamber; means for biasing said first and second electrodes enabling the electrodes to emit secondary electrons and create a glow discharge plasma within said chamber; and a magnet assembly for establishing a magnetic field adjacent to the boundary of said chamber to reflect electrons within said chamber away from the boundary.
Claim 6
Dependent Claim
46 words
The apparatus according to claim 3 wherein said means for biasing includes a source of a radio frequency signal, a transformer having a primary winding coupled to the source of a radio frequency signal and having a secondary winding coupled to the first and second electrodes.
Claim 7
Dependent Claim
34 words
The apparatus according to claim 2 or claim 4 wherein said means for biasing said first electrode assembly further includes a means for applying a d.c. bias potential to said first and second electrodes.
Claim 8
Independent Claim
50 words
The apparatus according to any one of claims 1 to 5 further comprising a control electrode located in the magnetic field within said chamber; and means for varying the location of said control electrode in the magnetic field to expose different surface areas of said control electrode to electron bombardment.
Claim 9
Independent Claim
76 words
The apparatus according to any one of claims 1 to 6 wherein: said chamber has a side wall assembly and a pair of end walls; and said means for establishing a surface magnetic field includes a first plurality of annular permanent magnets extending around the side wall assembly, a second plurality of annular permanent magnets adjacent one of the end walls, and a third plurality of annular permanent magnets adjacent the other of the end walls.
Claim 10
Dependent Claim
34 words
The apparatus according to claim 7 wherein the second plurality of annular permanent magnets are substantially coaxial to each other; and the third plurality of annular permanent magnets are substantially coaxial to each other.
Claim 11
Independent Claim
31 words
The apparatus according to any one of claims 1 to 6 wherein said means for establishing a surface magnetic field includes a plurality of annular permanent magnets extending around the chamber.
References Cited (Backward Citations)
CH648690A5
Cited
EP0330445A1
Cited
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