US4897287A
Expired / Lapsed
US
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Metallization process for an integrated circuit
Assignee: MCNC Research and Development Institute
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Filing: 1988-10-06
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Granted: 1990-01-30
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Expires: 2008-10-06
Abstract
Abstract A simple method for forming a metallization for an integrated circuit comprises depositing on a silicon substrate a first layer of refractory metal and nitrogen solid mixture and depositing thereon a second layer of refractory metal. The resulting structure is heated to convert the first layer to refractory metal nitride and the second layer to refractory metal silicide by flow of silicon from the substrate. By appropriate masking of the substrate, formation of silicide in the second layer can be blocked, thus permitting formation of self-aligned metallization by selective etching.
Inventors
- 👤 Henry R. Berger
- 👤 Gretchen M. Adema
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:50
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
74 words
A metallization process for a silicon substrate comprising the steps of: codepositing a refractory metal and nitrogen on said substrate to form a first layer of refractory metal and nitrogen solid mixture on said substrate; depositing a refractory metal on said first layer, to form a second layer of refractory metal on said first layer; and heating to convert said first layer into refractory metal nitride and said second layer into refractory metal silicide.
Claim 2
Dependent Claim
74 words
A metallization process for a silicon substrate comprising the steps of: codepositing a refractory metal and nitrogen on said substrate to form a first layer of refractory metal and nitrogen solid mixture on said substrate; depositing a refractory metal on said first layer, to form a second layer of refractory metal on said first layer; and heating to convert said first layer into refractory metal nitride and said second layer into refractory metal silicide.
Claim 3
Dependent Claim
11 words
The process of claim 1 wherein said refractory metal is titanium.
Claim 4
Dependent Claim
22 words
The process of claim 1 wherein said heating step comprises the step of heating at a temperature high enough to cause annealing.
Claim 5
Dependent Claim
22 words
The process of claim 1 wherein said codepositing step comprises the step of evaporating said refractory metal in a nitrogen containing ambient.
Claim 6
Dependent Claim
67 words
The process of claim 1 wherein said codepositing step is preceded by the step of: selectively masking said substrate to create covered portions and exposed portions thereof; and wherein said heating step converts first areas of said second layer above said exposed portions of said substrate to refractory metal silicide with second areas of said second layer above said covered portions of said substrate remaining refractory metal.
Claim 7
Dependent Claim
34 words
The process of claim 5 further comprising the step of removing said second areas of said second layer and the portion of said first layer which underlies said second areas of said second layer.
Claim 8
Dependent Claim
15 words
The process of claim 5 wherein silicon dioxide is used to selectively mask said substrate.
Claim 9
Dependent Claim
78 words
A metallization process for a silicon substrate comprising the steps of: codepositing a refractory metal and nitrogen on said substrate, to form a first layer of a refractory metal and nitrogen solid mixture thereon; terminating the codeposition of nitrogen and continuing to deposit said refractory metal to form a second layer of said refractory metal on said first layer; and heating to convert said first layer into refractory metal nitride and said second layer into refractory metal silicide.
Claim 10
Dependent Claim
78 words
A metallization process for a silicon substrate comprising the steps of: codepositing a refractory metal and nitrogen on said substrate, to form a first layer of a refractory metal and nitrogen solid mixture thereon; terminating the codeposition of nitrogen and continuing to deposit said refractory metal to form a second layer of said refractory metal on said first layer; and heating to convert said first layer into refractory metal nitride and said second layer into refractory metal silicide.
Claim 11
Dependent Claim
22 words
The process of claim 8 wherein said heating step comprises the step of heating at a temperature high enough to cause annealing.
Claim 12
Dependent Claim
22 words
The process of claim 8 wherein said codepositing step comprises the step of evaporating said refractory metal in a nitrogen containing ambient.
Claim 13
Dependent Claim
67 words
The process of claim 8 wherein said codepositing step is preceded by the step of: selectively masking said substrate to create covered portions and exposed portions thereof; and wherein said heating step converts first areas of said second layer above said exposed portions of said substrate to refractory metal silicide with second areas of said second layer above said covered portions of said substrate remaining refractory metal.
Claim 14
Dependent Claim
34 words
The process of claim 11 further comprising the step of removing said second areas of said second layer and those portions of said first layer which underlie said second areas of said second layer.
Claim 15
Dependent Claim
78 words
A metallization process for a silicon substrate comprising the steps of: evaporating a refractory metal on said substrate, in a nitrogen flow, to form a first layer of refractory metal and nitride solid mixture on said substrate; terminating said nitrogen flow to thereby form a second layer of refractory metal on said first layer; terminating the evaporation of said refractory metal; and annealing to convert said first layer into refractory metal nitride and/said second layer into refractory metal.
Claim 16
Dependent Claim
78 words
A metallization process for a silicon substrate comprising the steps of: evaporating a refractory metal on said substrate, in a nitrogen flow, to form a first layer of refractory metal and nitride solid mixture on said substrate; terminating said nitrogen flow to thereby form a second layer of refractory metal on said first layer; terminating the evaporation of said refractory metal; and annealing to convert said first layer into refractory metal nitride and/said second layer into refractory metal.
Claim 17
Dependent Claim
67 words
The process of claim 13 wherein said evaporating step is preceded by the step of: selectively masking said substrate to create covered portions and exposed portions thereof; and wherein said annealing step converts first areas of said second layer above said exposed portions of said substrate to refractory metal silicide with second areas of said second layer above said covered portions of said substrate remaining refractory metal.
Claim 18
Dependent Claim
34 words
The process of claim 14 further comprising the step of removing said second areas of said second layer and those portions of said first layer which underlie said second areas of said second layers.
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) | 1993-01-29 | 1993-07-31 | 1994-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-29 | 1997-07-31 | 1998-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-29 | 2001-07-31 | 2002-01-30 | $7700.00 | Window Closed / Lapsed |