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US4419201A
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US
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Apparatus and method for plasma-assisted etching of wafers
Assignee: Agere Systems LLC
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Filing: 1981-08-24
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Granted: 1983-12-06
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Expires: 2001-08-24
Abstract
Abstract In a plasma-assisted etching apparatus and method designed to pattern aluminum or polysilicon, surfaces in the reaction chamber are coated with a layer of aluminum oxide. Contamination of wafers during the etching process is thereby substantially reduced. In practice, this leads to a significant increase in the yield of acceptable chips per wafer.
Inventors
- 👤 Hyman J. Levinstein
- 👤 Frederick Vratny
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:18
CPC Classifications
H; H10; H10P; H10P70/00; H10P70/20; H10P70/27; H10P70/273; H01; H01J; H01J37/00; H01J37/32; H01J37/32431; H01J37/32532; H01J37/32559; H01J37/34; H10P50/00; H10P50/20; H10P50/26; H10P50/264; H10P50/266; H10P50/267; H10P50/268; H01J2237/00; H01J2237/20; Y; Y10; Y10S; Y10S156/00; Y10S156/914; Y10S156/917
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
88 words
Apparatus for low-contamination plasma-assisted dry etching of an aluminum layer formed on a wafer, said apparatus comprising a reaction chamber, means for establishing within said chamber an etching plasma derived from a mixture of boron trichloride and chlorine gases, said chamber including surfaces exposed to said plasma, and a coating of aluminum oxide on at least the surfaces in the immediate vicinity of the wafer to be etched, wherein said coating comprises individual particles of crystalline-β aluminum oxide fused together on said surfaces in a plasma spraying process.
Claim 2
Dependent Claim
88 words
Apparatus for low-contamination plasma-assisted dry etching of an aluminum layer formed on a wafer, said apparatus comprising a reaction chamber, means for establishing within said chamber an etching plasma derived from a mixture of boron trichloride and chlorine gases, said chamber including surfaces exposed to said plasma, and a coating of aluminum oxide on at least the surfaces in the immediate vicinity of the wafer to be etched, wherein said coating comprises individual particles of crystalline-β aluminum oxide fused together on said surfaces in a plasma spraying process.
Claim 3
Dependent Claim
24 words
An apparatus as in claim 1 further including a cathode electrode in said reaction chamber, and means mounting said wafer on said cathode electrode.
Claim 4
Dependent Claim
131 words
Apparatus for low-contamination plasma-assisted dry etching of a layer of aluminum or polysilicon on a wafer that is to be processed to form multiple VLSI circuits, said apparatus comprising a reaction chamber, means for establishing within said chamber an etching plasma derived from a mixture of boron trichloride and chlorine gases, means within said chamber for holding a number of wafers to be etched, said chamber having internal surfaces including surfaces of said holding means in the immediate vicinity of said wafers to be etched, and a coating of aluminum oxide formed on internal surfaces including at least the surfaces of said holding means in the immediate vicinity of said wafers, wherein said coating comprises individual particles of crystalline-β aluminum oxide fused together on said surfaces in a plasma spraying process.
Claim 5
Dependent Claim
131 words
Apparatus for low-contamination plasma-assisted dry etching of a layer of aluminum or polysilicon on a wafer that is to be processed to form multiple VLSI circuits, said apparatus comprising a reaction chamber, means for establishing within said chamber an etching plasma derived from a mixture of boron trichloride and chlorine gases, means within said chamber for holding a number of wafers to be etched, said chamber having internal surfaces including surfaces of said holding means in the immediate vicinity of said wafers to be etched, and a coating of aluminum oxide formed on internal surfaces including at least the surfaces of said holding means in the immediate vicinity of said wafers, wherein said coating comprises individual particles of crystalline-β aluminum oxide fused together on said surfaces in a plasma spraying process.
Claim 6
Dependent Claim
110 words
A low-contamination method for fabricating VLSI devices by delineating fine-line patterns on a wafer in accordance with a process sequence that includes plasma-assisted dry etching, the wafer including a layer of aluminum or polysilicon to be etched, said method comprising the steps of mounting said wafer to be etched in a reaction chamber having surfaces in the immediate vicinity of the wafer coated with a layer of aluminum oxide, and establishing within said chamber an etching plasma derived from a mixture of boron trichloride and chlorine gases, wherein said layer of aluminum oxide comprises individual particles of crystalline-β aluminum oxide fused together on said surfaces in a plasma spraying step.
Claim 7
Dependent Claim
110 words
A low-contamination method for fabricating VLSI devices by delineating fine-line patterns on a wafer in accordance with a process sequence that includes plasma-assisted dry etching, the wafer including a layer of aluminum or polysilicon to be etched, said method comprising the steps of mounting said wafer to be etched in a reaction chamber having surfaces in the immediate vicinity of the wafer coated with a layer of aluminum oxide, and establishing within said chamber an etching plasma derived from a mixture of boron trichloride and chlorine gases, wherein said layer of aluminum oxide comprises individual particles of crystalline-β aluminum oxide fused together on said surfaces in a plasma spraying step.
Claim 8
Dependent Claim
28 words
A method as in claim 4 wherein a cathode electrode is included in said reaction chamber and said wafer to be etched is mounted on said cathode electrode.
Claim 9
Dependent Claim
78 words
A method as in claim 5 wherein said establishing step includes establishing the following conditions in said reaction chamber: a pressure of approximately 20 micrometers, a power density of approximately 0.15 watts per square centimeter at the surface of the layer to be etched, a gas flow into said chamber of approximately 75 cubic centimeters per minute and a dc bias voltage of said cathode electrode with respect to a point of reference potential of approximately 210 volts.
Claim 10
Dependent Claim
87 words
Apparatus for low-contamination plasma-assisted dry etching of a polysilicon layer formed on a wafer, said apparatus comprising a reaction chamber, means for establishing within said chamber an etching plasma derived from essentially pure chlorine gas, said chamber including surfaces exposed to said plasma, and a coating of aluminum oxide on at least the surfaces in the immediate vicinity of the wafer to be etched, wherein said layer of aluminum oxide comprises individual particles of crystalline-β aluminum oxide fused together on said surfaces in a plasma spraying step.
Claim 11
Dependent Claim
87 words
Apparatus for low-contamination plasma-assisted dry etching of a polysilicon layer formed on a wafer, said apparatus comprising a reaction chamber, means for establishing within said chamber an etching plasma derived from essentially pure chlorine gas, said chamber including surfaces exposed to said plasma, and a coating of aluminum oxide on at least the surfaces in the immediate vicinity of the wafer to be etched, wherein said layer of aluminum oxide comprises individual particles of crystalline-β aluminum oxide fused together on said surfaces in a plasma spraying step.
Claim 12
Dependent Claim
102 words
A low-contamination method for fabricating VLSI devices by delineating fine-line patterns on a wafer in accordance with a process sequence that includes plasma-assisted dry etching, the wafer including a layer of polysilicon to be etched, said method comprising the steps of mounting said wafer to be etched in a reaction chamber having surfaces in the immediate vicinity of the wafer coated with a layer of aluminum oxide, and establishing within said chamber an etching plasma derived from chlorine gas, wherein said layer of aluminum oxide comprises individual particles of crystalline-β aluminum oxide fused together on said surfaces in a plasma spraying step.
Claim 13
Dependent Claim
102 words
A low-contamination method for fabricating VLSI devices by delineating fine-line patterns on a wafer in accordance with a process sequence that includes plasma-assisted dry etching, the wafer including a layer of polysilicon to be etched, said method comprising the steps of mounting said wafer to be etched in a reaction chamber having surfaces in the immediate vicinity of the wafer coated with a layer of aluminum oxide, and establishing within said chamber an etching plasma derived from chlorine gas, wherein said layer of aluminum oxide comprises individual particles of crystalline-β aluminum oxide fused together on said surfaces in a plasma spraying step.
References Cited (Backward Citations)
US4268347A
Cited
US4298443A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-12-05 | 1987-06-06 | 1987-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-05 | 1991-06-06 | 1991-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-05 | 1995-06-06 | 1995-12-06 | $7700.00 | Window Closed / Lapsed |