US5041394A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming protective barrier on silicided regions
Assignee: Texas Instruments Inc
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Filing: 1991-01-07
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Granted: 1991-08-20
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Expires: 2011-01-07
Abstract
Abstract The described embodiments of the present invention provide a protective layer on the surface of silicided regions and methods for its formation. In the primary described embodiment, a titanium silicide layer is formed in integrated circuitry using self-aligned techniques. Local interconnection layers may be formed using biproducts of the self-aligned titanium disilicide formation. A layer of another siliciding metal, for example platinum, is then formed overall. The platinum layer is then subjected to an annealing step which causes a portion of the silicon in the titanium disilicide layers to react with the platinum to form platinum silicide. This platinum silicide layer is formed in a self-aligned manner on the surface of the silicided regions. The platinum silicide layer serves to protect the underlying titanium disilicide layer from subsequent etching steps of other harmful processing operations.
Inventors
- 👤 David B. Spratt
- 👤 Robert H. Eklund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:38
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0112; H10D64/013; H10D64/01302; H10D64/01304; H10D64/01306; H10D64/01308; H10D64/0131; Y; Y10; Y10S; Y10S148/00; Y10S148/019; Y10S148/147
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
185 words
A method for forming a protective layer in an integrated circuit, comprising the steps of: providing a silicon substrate; forming and patterning a protective layer on said substrate; forming a doped region on said substrate; depositing a layer of a first metal overall; reacting said first metal with said doped region where said doped region is not covered by said protective layer to form a first metal silicide; selectively removing the unreacted portion of said first metal; depositing a layer of a second metal overall which is a different material than said first metal; reacting said second metal with said first metal silicide to form a protective metal silicide layer over said first silicide layer and having a first etching selectivity; selectively removing the unreacted portion of said layer of second metal; forming a layer of a selected material over portions of said integrated circuit, including said protective metal silicide layer said selected material having a different etching selectivity than said protective silicide; and selectively etching to remove said selected material to expose without removing at least a portion of said protective metal silicide layer.
Claim 2
Independent Claim
185 words
A method for forming a protective layer in an integrated circuit, comprising the steps of: providing a silicon substrate; forming and patterning a protective layer on said substrate; forming a doped region on said substrate; depositing a layer of a first metal overall; reacting said first metal with said doped region where said doped region is not covered by said protective layer to form a first metal silicide; selectively removing the unreacted portion of said first metal; depositing a layer of a second metal overall which is a different material than said first metal; reacting said second metal with said first metal silicide to form a protective metal silicide layer over said first silicide layer and having a first etching selectivity; selectively removing the unreacted portion of said layer of second metal; forming a layer of a selected material over portions of said integrated circuit, including said protective metal silicide layer said selected material having a different etching selectivity than said protective silicide; and selectively etching to remove said selected material to expose without removing at least a portion of said protective metal silicide layer.
Claim 3
Dependent Claim
16 words
A method as in claim 1 wherein said silicon substrate is a single crystal silicon substrate.
Claim 4
Dependent Claim
13 words
A method as in claim 1 wherein said protective layer comprises silicon dioxide.
Claim 5
Dependent Claim
12 words
A method as in claim 1 wherein said first metal is titanium.
Claim 6
Dependent Claim
12 words
A method as in claim 1 wherein said second metal is platinum.
Claim 7
Dependent Claim
18 words
A method as in claim 1 wherein said first metal is titanium and said second metal is platinum.
Claim 8
Dependent Claim
25 words
A method as in claim 1 wherein said reacting of said second metal is performed by heating to a temperature of less than 600° Celsius.
Claim 9
Dependent Claim
41 words
A method as in claim 1 wherein said selected material is an insulating layer and further including the step of depositing a conductive layer in a selected pattern over said insulating layer and in contact with said protective metal silicide layer.
Claim 10
Independent Claim
202 words
A method for forming a protective layer in an integrated circuit, comprising the steps of: providing a silicon substrate; forming and patterning a protective layer on said substrate; forming a doped region on said substrate; depositing a layer of a first metal overall; reacting said first metal with said doped region where said doped region is not covered by said protective layer to form a first metal silicide, the portion of said first metal which does not react with said substrate providing a conductive layer; patterning said conductive layer to provide selected electrical interconnections; depositing a layer of a second metal overall which is a different material than said first metal; reacting said second metal with said first metal silicide to form a protective metal silicide layer over said first silicide layer and having a first etching selectivity; selectively removing the unreacted portion of said layer of second metal; forming a layer of a selected material over portions of said integrated circuit, including said protective metal silicide layer, said selective material having a different etching selectivity than said protective silicide; and selectively etching to remove said selected material to expose without removing at least a portion of said protective metal silicide layer.
Claim 11
Independent Claim
202 words
A method for forming a protective layer in an integrated circuit, comprising the steps of: providing a silicon substrate; forming and patterning a protective layer on said substrate; forming a doped region on said substrate; depositing a layer of a first metal overall; reacting said first metal with said doped region where said doped region is not covered by said protective layer to form a first metal silicide, the portion of said first metal which does not react with said substrate providing a conductive layer; patterning said conductive layer to provide selected electrical interconnections; depositing a layer of a second metal overall which is a different material than said first metal; reacting said second metal with said first metal silicide to form a protective metal silicide layer over said first silicide layer and having a first etching selectivity; selectively removing the unreacted portion of said layer of second metal; forming a layer of a selected material over portions of said integrated circuit, including said protective metal silicide layer, said selective material having a different etching selectivity than said protective silicide; and selectively etching to remove said selected material to expose without removing at least a portion of said protective metal silicide layer.
Claim 12
Dependent Claim
16 words
A method as in claim 9 wherein said silicon substrate is a single crystal silicon substrate.
Claim 13
Dependent Claim
13 words
A method as in claim 9 wherein said protective layer comprises silicon dioxide.
Claim 14
Dependent Claim
12 words
A method as in claim 9 wherein said first metal is titanium.
Claim 15
Dependent Claim
12 words
A method as in claim 9 wherein said second metal is platinum.
Claim 16
Dependent Claim
18 words
A method as in claim 9 wherein said first metal is titanium and said second metal is platinum.
Claim 17
Dependent Claim
25 words
A method as in claim 9 wherein said reacting of said second metal is performed by heating to a temperature of less than 600° Celsius.
Claim 18
Dependent Claim
35 words
A method as in claim 9 wherein said conductive layer comprises a product of the reaction of said first metal with an ambient gas, said ambient gas being present during said reacting said first metal.
Claim 19
Dependent Claim
12 words
A method as in claim 16 wherein said ambient gas in nitrogen.
Claim 20
Dependent Claim
18 words
A method as in claim 16 wherein said ambient gas is nitrogen and said first metal is titanium.
References Cited (Backward Citations)
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