US5100501A
Expired / Lapsed
US
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Process for selectively depositing a metal in vias and contacts by using a sacrificial layer
Assignee: Texas Instruments Inc
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Filing: 1989-06-30
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Granted: 1992-03-31
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Expires: 2009-06-30
Abstract
Abstract A process for selectively depositing a contacting material (20) in trenches (18) for a via or contact which selectively eliminates potential metal contaminants (22) by removing a sacrificial layer (16) after the material (20) is selectively deposited. Initially, the trenches (18) are formed by selectively exposing the substrate (10) to an etchant (19). After metal material (20) is deposited into the formed trenches (18), a chemical etchant (24) is used to remove the sacrificial layer (16) and any formed contaminants (22).
Inventors
- 👤 Roc Blumenthal
- 👤 Rebecca J. Gale
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:24
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/056; H10W20/058
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
102 words
A process for selectively depositing a contacting metal in trenches of a substrate, comprising the steps of: placing an oxide layer on the substrate; placing, on the oxide layer, a sacrificial layer selected from the group consisting of silicon nitride, silicon oxide, atmospheric pressure chemical vapor deposition oxide, undensified spin on glass or a combination thereof, an oxide layer/sacrificial layer interface being formed there between; etching trenches in the substrate to a desired configuration; placing the contacting metal in the trenches to a level substantially even with the oxide layer/sacrificial layer interface; and chemically removing the sacrificial layer with an acidic etchant.
Claim 2
Dependent Claim
102 words
A process for selectively depositing a contacting metal in trenches of a substrate, comprising the steps of: placing an oxide layer on the substrate; placing, on the oxide layer, a sacrificial layer selected from the group consisting of silicon nitride, silicon oxide, atmospheric pressure chemical vapor deposition oxide, undensified spin on glass or a combination thereof, an oxide layer/sacrificial layer interface being formed there between; etching trenches in the substrate to a desired configuration; placing the contacting metal in the trenches to a level substantially even with the oxide layer/sacrificial layer interface; and chemically removing the sacrificial layer with an acidic etchant.
Claim 3
Dependent Claim
17 words
The process of claim 1, wherein the contacting metal comprises tungsten, copper, nickel, molybdenium, tantalum, or titanium.
Claim 4
Dependent Claim
22 words
The process of claim 1, wherein said stop of etching trenches is conducted by exposing the substrate to a fluorine based-plasma etchant.
Claim 5
Dependent Claim
26 words
The process of claim 2, wherein said removing step is conducted such that the sacrificial layer is stripped off at a faster rate than the substrate.
Claim 6
Dependent Claim
25 words
The process of claim 1, wherein said step of depositing the sacrificial layer creates a layer having a thickness between approximately 1000 to 1500 angstroms.
Claim 7
Dependent Claim
21 words
The process of claim 1, wherein said trench is formed with a width between approximately 6000 angstroms to approximately 10,000 angstroms.
Claim 8
Dependent Claim
33 words
The process of claim 1, wherein said contacting metal is selected form the group consisting of copper, nickel, molybdenum, tantalum, tantalum silicide, titanium, titanium silicide, titanium nitride, aluminum, a combination thereof and tungsten.
Claim 9
Dependent Claim
92 words
A process for depositing a contacting metal in trenches of a substrate formed on a contacting layer comprising the steps of: depositing an oxide layer on the substrate; depositing a layer of silicon nitride on the oxide layer thereby forming an oxide layer/silicon nitride interface; etching trenches through said silicon nitride layer, said oxide layer, and said substrate to expose the contacting layer; selectively filling the trenches with a tungsten metal to a level substantially even with said oxide layer/silicon nitride interface; and removing the silicon nitride layer with a phosphoric acid.
Claim 10
Dependent Claim
92 words
A process for depositing a contacting metal in trenches of a substrate formed on a contacting layer comprising the steps of: depositing an oxide layer on the substrate; depositing a layer of silicon nitride on the oxide layer thereby forming an oxide layer/silicon nitride interface; etching trenches through said silicon nitride layer, said oxide layer, and said substrate to expose the contacting layer; selectively filling the trenches with a tungsten metal to a level substantially even with said oxide layer/silicon nitride interface; and removing the silicon nitride layer with a phosphoric acid.
Claim 11
Dependent Claim
19 words
The process of claim 8, wherein said trenches have a width between approximately 6000 angstroms and approximately 10,000 angstroms.
Claim 12
Dependent Claim
23 words
The process of claim 8, wherein said step of etching the trenches is conducted by exposing the substrate to a fluorine based-plasma etchant.
Claim 13
Dependent Claim
23 words
The process of claim 8, wherein said removing step comprises stripping the silicon nitride layer off at a faster rate than the substrate.
Claim 14
Dependent Claim
28 words
The process of claim 8, wherein said removing step comprises applying hot phosphoric acid having a temperature of approximately 160 degrees centigrade to remove the silicon nitride layer.
Claim 15
Dependent Claim
25 words
The process of claim 8, wherein said step of depositing forms a silicon nitride layer of between approximately 1000 angstroms to 1500 angstroms in thickness.
Claim 16
Dependent Claim
22 words
The process of claim 12, wherein said thickness of said silicon nitride layer is proportional to the exposure time to phosphoric acid.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1995-03-31 | 1995-09-30 | 1996-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-03-31 | 1999-09-30 | 2000-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-03-31 | 2003-09-30 | 2004-03-31 | $7700.00 | Window Closed / Lapsed |