Patent US4855015A successfully refreshed from Google Patents.
US4855015A
Expired / Lapsed
US
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Dry etch process for selectively etching non-homogeneous material bilayers
Assignee: Texas Instruments Inc
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Filing: 1988-04-29
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Granted: 1989-08-08
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Expires: 2008-04-29
Abstract
Abstract A plasma etching process employs a halogen liberating gas to selectively etch a top semiconductor layer of a bilayer with respect to a bottom semiconductor layer. A fluorine rich gas reacts with a top germanium layer for removal thereof, while forming a passivating surface layer on a bottom silicon layer to inhibit the silicon' plasma reaction therewith.
Inventors
- 👤 Monte A. Douglas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:26
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/24; H10P50/242
Claims Analysis
Total Claims: 46
Claim 1
Independent Claim
74 words
A method for etching semiconductor materials employed in fabricating semiconductor circuits, comprising the steps of: forming a pair of semiconductor material films having a first film of semiconductor material and second film of a different semiconductor material; and selectively etching said first film with an etch process which etches said first film faster than said second film so that when said first film is removed, the second film is removed at a slower rate.
Claim 2
Independent Claim
74 words
A method for etching semiconductor materials employed in fabricating semiconductor circuits, comprising the steps of: forming a pair of semiconductor material films having a first film of semiconductor material and second film of a different semiconductor material; and selectively etching said first film with an etch process which etches said first film faster than said second film so that when said first film is removed, the second film is removed at a slower rate.
Claim 3
Dependent Claim
16 words
The method of claim 1, further including etching said first film using a dry etch process.
Claim 4
Dependent Claim
17 words
The method of claim 2, further including etching said first film by employing a plasma etch process.
Claim 5
Dependent Claim
17 words
The method of claim 1, wherein said second film comprises silicon, and said first film comprises germanium.
Claim 6
Dependent Claim
20 words
The method of claim 4, further including etching said germanium using a plasma process with a halogen liberating gas source.
Claim 7
Dependent Claim
14 words
The method of claim 4, further including etching said first film with carbon tetrafluoride.
Claim 8
Dependent Claim
14 words
The method of claim 4, further including etching said first film with sulfur hexafluoride.
Claim 9
Dependent Claim
34 words
The method of claim 1, wherein said etch is adapted to etch said first film at a rate of at least 1.5 times greater than the rate by which said second film is etchable.
Claim 10
Dependent Claim
43 words
The method of claim 1, further including etching said first film with a gas which is adapted for forming a passivation layer on said second film so that said second film is etched at a different rate than that of said first film.
Claim 11
Dependent Claim
22 words
The method of claim 9, further including employing a plasma reacting gas which forms a monomolecular passivating layer on said second film.
Claim 12
Dependent Claim
45 words
The method of claim 9, further including using a plasma reacting gas which produces molecular radicals having a higher sticking coefficient with the second film relative to the first film to passivate on a molecular scale the second film to reduce the etch rate thereof.
Claim 13
Dependent Claim
49 words
The method of claim 9, further including employing a plasma reacting gas which produces a high concentration of molecular radicals that have a high sticking coefficient and a high surface concentration on the second film so as to form polymers or agglomerate macroscopically and thereby form said passivation layer.
Claim 14
Dependent Claim
34 words
The method of claim 1, further including using an end point detector for detecting when the first film is removed and when said second film is exposed to the etchants of the etching process.
Claim 15
Dependent Claim
16 words
The method of claim 1, further including forming a bilayer of said first and second films.
Claim 16
Dependent Claim
19 words
The method of claim 1, further including forming said first film and said second film as laterally situated layers.
Claim 17
Independent Claim
68 words
A method for etching semiconductor materials employed in fabricating semiconductor circuits, comprising the steps of: forming a material bilayer having a top layer of semiconductor material disposed on a base layer of a different semiconductor material; and etching said top layer of material with a plasma process using a halogen liberating gas source such that said top layer is etched at a rate faster than said base layer,
Claim 18
Independent Claim
68 words
A method for etching semiconductor materials employed in fabricating semiconductor circuits, comprising the steps of: forming a material bilayer having a top layer of semiconductor material disposed on a base layer of a different semiconductor material; and etching said top layer of material with a plasma process using a halogen liberating gas source such that said top layer is etched at a rate faster than said base layer,
Claim 19
Dependent Claim
20 words
The method of claim 16, further including forming said bilayer with a germanium material formed over a silicon base material.
Claim 20
Dependent Claim
17 words
The method of claim 16, further including employing a fluorine-based liberating gas source in said etching process.
Claim 21
Dependent Claim
10 words
The method of claim 18, further including employing sulfur hexafluoride.
Claim 22
Dependent Claim
15 words
The method of claim 18, further including employing carbon tetrafluoride as said halogen liberating gas.
Claim 23
Independent Claim
71 words
A method for etching materials employed in fabricating semiconductor circuits, comprising the steps of: forming a material bilayer having a top layer of material disposed on a base layer of a different material; and etching said top layer material with a dry etch which etches said top layer and which forms a passivating layer on said base layer so that said top layer is etched substantially faster than said base layer.
Claim 24
Independent Claim
71 words
A method for etching materials employed in fabricating semiconductor circuits, comprising the steps of: forming a material bilayer having a top layer of material disposed on a base layer of a different material; and etching said top layer material with a dry etch which etches said top layer and which forms a passivating layer on said base layer so that said top layer is etched substantially faster than said base layer.
Claim 25
Dependent Claim
17 words
The method of claim 21, wherein said dry etch is carried out by employing a plasma process.
Claim 26
Dependent Claim
16 words
The method of claim 22, further including employing a halogen liberating gas and a plasma reaction.
Claim 27
Dependent Claim
15 words
The method of claim 23, further including employing carbon tetrafluoride as said halogen liberating gas.
Claim 28
Dependent Claim
15 words
The method of claim 23, further including employing sulfur hexafluoride as said halogen liberating gas.
Claim 29
Dependent Claim
22 words
The method of claim 21, further including employing a halogen liberating source to form a polymer passivating layer on said base layer.
Claim 30
Dependent Claim
20 words
The method of claim 21, further including forming said top layer with germanium and forming said base layer with silicon.
Claim 31
Dependent Claim
20 words
The method of claim 21, further including forming a monomolecular passivating layer on a top surface of said base layer.
Claim 32
Independent Claim
67 words
A method for etching materials employed in fabricating semiconductor circuits, comprising the steps of: forming a material bilayer having a top layer material disposed on a base layer of a different material; plasma etching said top layer; sampling plasma reaction by-products to detect when said base layer is exposed to the plasma reaction; and halting said plasma reaction when said base material is detected in said sample.
Claim 33
Independent Claim
67 words
A method for etching materials employed in fabricating semiconductor circuits, comprising the steps of: forming a material bilayer having a top layer material disposed on a base layer of a different material; plasma etching said top layer; sampling plasma reaction by-products to detect when said base layer is exposed to the plasma reaction; and halting said plasma reaction when said base material is detected in said sample.
Claim 34
Dependent Claim
16 words
The method of claim 29, further including forming a germanium top layer over said base layer.
Claim 35
Dependent Claim
31 words
The method of claim 30, further including detecting a germanium species in the etched by-product, and then detecting a minimum germanium by-product and as a result thereof halting the etching process.
Claim 36
Dependent Claim
26 words
The method of claim 29, further including carrying out said etching process with a selective etch which etches the top layer faster than the base layer.
Claim 37
Independent Claim
48 words
A method for etching a semiconductor material, comprising the steps of: selecting a dry etch chemistry having a halogen liberating property; igniting a plasma reaction in the presence of said dry etch chemistry; and subjecting the semiconductor directly to plasma ions and electrons produced by said plasma reaction.
Claim 38
Independent Claim
48 words
A method for etching a semiconductor material, comprising the steps of: selecting a dry etch chemistry having a halogen liberating property; igniting a plasma reaction in the presence of said dry etch chemistry; and subjecting the semiconductor directly to plasma ions and electrons produced by said plasma reaction.
Claim 39
Dependent Claim
20 words
The method of claim 33, further including selecting an etch chemistry which liberates fluorine atoms during the plasma etch process.
Claim 40
Dependent Claim
20 words
The method of claim 33, further including selecting etch chemistry reactants which form a macroscopic passivation layer on said germanium.
Claim 41
Dependent Claim
35 words
The method of claim 33, further including forming a non-homogeneous bilayer of material, one said layer being said germanium, and selecting an etch chemistry which etches the materials of said bilayer with diverse etch rates.
Claim 42
Dependent Claim
24 words
The method of claim 36, further including selecting an etch chemistry which etches the germanium substantially faster than said other material of said bilayer.
Claim 43
Dependent Claim
16 words
The method of claim 37, further including forming said bilayer using silicon as one material layer.
Claim 44
Dependent Claim
20 words
The method of claim 33, further including etching said germanium at a rate of at least 3,000 angstroms per minute.
Claim 45
Dependent Claim
15 words
The method of claim 39, further including etching said germanium using a carbon tetrafluoride chemistry.
Claim 46
Dependent Claim
26 words
The method of claim 40, further including etching said germanium using about 175 watts of RF energy and a reaction chamber pressure of about 1.5 torr.
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) | 1992-08-07 | 1993-02-06 | 1993-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-07 | 1997-02-06 | 1997-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-07 | 2001-02-06 | 2001-08-08 | $7700.00 | Window Closed / Lapsed |