EP0261922A2
Expired / Lapsed
EP
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Electrode assembly and apparatus
Assignee: Nordiko Ltd
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Filing: 1987-09-21
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Granted: —
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Expires: 2007-09-21
Abstract
Abstract An electrode assembly (5) is described for use in plasma processes, such as reactive dry etching and plasma deposition. This includes a primary electrode (11, 17) which is electrically insulated from the vacuum chamber (1) in which it is mounted in use. The primary electrode (11, 17) may be connected to an r.f. or d.c. power source and has a cylindrical hole with an insulated subsidiary electrode (18) at the bottom of the hole which can be earthed (28) or allowed to adopt a floating voltage in use. Magnets (16) are used to trap electrons adjacent the walls of the hole. These may consist of a plurality of elongate magnets (16) positioned around an annular pole plate (15) with their largest dimension arranged longitudinally with respect to the pole plate and the hole, with their magnetic axes arranged radially, and with alternating polarity around the inner periphery of the pole plate. In use an r.f. frequency (e.g. 13.56 MHz) may be applied to the primary electrode whilst a reactant gas (e.g. C₂F₆ or a C₂F₆/CHF₃ mixture) is admitted to the vacuum chamber. The silicon wafer or other substrate (9) to be etched is placed on a substrate table (7) within the chamber which can also be connected to an r.f. power source.
Inventors
- 👤 Mervyn Howard Davis
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 09:46
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32431; H01J37/3266; H01J37/32688; C; C23; C23C; C23C16/00; C23C16/44; C23C16/50; C23C16/505; C23C16/509; C23C16/5096; H01J37/32009; H01J37/32082; H01J37/32623
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
137 words
An electrode assembly for use in plasma processing apparatus comprising mounting means for mounting the assembly in a vacuum chamber, a primary electrode having a hole formed therein, insulating means for insulating the primary electrode from the body of the vacuum chamber, means for connecting the primary electrode to an r.f. or d.c. power source, a subsidiary electrode mounted within or adjacent the hole and electrically insulated from the primary electrode, and magnet means for trapping electrons adjacent the wall of the hole in use of the assembly by producing lines of magnetic flux within the hole which extend in a curve from the wall of the hole and return thereto so as to form an arch over a respective one of a plurality of wall regions which extend substantially longitudinally of the wall of the hole.
Claim 2
Dependent Claim
137 words
An electrode assembly for use in plasma processing apparatus comprising mounting means for mounting the assembly in a vacuum chamber, a primary electrode having a hole formed therein, insulating means for insulating the primary electrode from the body of the vacuum chamber, means for connecting the primary electrode to an r.f. or d.c. power source, a subsidiary electrode mounted within or adjacent the hole and electrically insulated from the primary electrode, and magnet means for trapping electrons adjacent the wall of the hole in use of the assembly by producing lines of magnetic flux within the hole which extend in a curve from the wall of the hole and return thereto so as to form an arch over a respective one of a plurality of wall regions which extend substantially longitudinally of the wall of the hole.
Claim 3
Dependent Claim
31 words
An electrode assembly according to claim 1, in which the hole is a cavity and in which the subsidiary electrode forms at least a part of the bottom of the cavity.
Claim 4
Dependent Claim
21 words
An electrode assembly according to claim 1 or claim 2, in which the subsidiary electrode is arranged for connection to earth.
Claim 5
Dependent Claim
21 words
An electrode assembly according to any one of claims 1 to 3, in which the hole has a substantially cylindrical wall.
Claim 6
Dependent Claim
70 words
An electrode assembly according to any one of claims 1 to 4, in which the magnet means comprises an annular pole plate and a plurality of elongate magnets magnetically coupled with the pole plate each aligned substantially longitudinally with respect to the hole and each having its magnetic axis aligned substantially radially with respect to the hole, and in which the polarities of the magnets alternate around the pole plate.
Claim 7
Dependent Claim
21 words
An electrode assembly according to claim 5, in which the magnets are positioned on the inside face of the pole plate.
Claim 8
Dependent Claim
21 words
An electrode assembly according to claim 5 or claim 6, in which the pole plate has cylindrical inner and outer surfaces.
Claim 9
Dependent Claim
26 words
An electrode assembly according to any one of claims 1 to 7, in which the primary electrode is provided with an aluminium or aluminium alloy cladding.
Claim 10
Dependent Claim
18 words
An electrode assembly according to claim 8, in which the cladding includes a cylindrical lining to the hole.
Claim 11
Dependent Claim
79 words
Plasma processing apparatus for treating a substrate under plasma forming conditions in a reactant gas atmosphere comprising a vacuum chamber, a substrate table within the vacuum chamber for supporting a substrate to be treated, means for connecting the substrate table to a power source, an electrode assembly according to any one of claims 1 to 9, vacuum pump means for evacuating the vacuum chamber, and means for introducing a reactant gas into the chamber for treatment of the substrate.
Claim 12
Dependent Claim
17 words
Apparatus according to claim 10, in which the primary electrode is connected to an r.f. power source.
Claim 13
Dependent Claim
30 words
Apparatus according to claim 10 or claim 11, in which separate r.f. power sources are used to provide r.f. power to the primary electrode and to the substrate table respectively.
Claim 14
Dependent Claim
31 words
Apparatus according to claim 10 or claim 11, in which a single r.f. power supply is used, the output from which is divided between the primary electrode and the substrate table.
Claim 15
Dependent Claim
17 words
Apparatus according to claim 10, in which the primary electrode is connected to a d.c. power source.
Claim 16
Dependent Claim
34 words
A reactive dry etching process in which there is used an electrode assembly according to any one of claims 1 to 9 or an apparatus according to any one of claims 10 to 14.
Claim 17
Dependent Claim
33 words
A plasma deposition process in which there is used an electrode assembly according to any one of claims 1 to 9 or an apparatus according to any one of claims 10 to 14.
References Cited (Backward Citations)
No citation records indexed.
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