US5891802A
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US
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Method for fabricating a metallization stack structure to improve electromigration resistance and keep low resistivity of ULSI interconnects
Assignee: GlobalFoundries Inc
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Filing: 1997-07-23
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Granted: 1999-04-06
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Expires: 2017-07-23
Abstract
Abstract There is provided an improved metallization stack structure and a method for fabricating the same so as to produce a higher electromigration resistance and yet maintain a relatively low resistivity. The metallization stack structure includes a pure copper layer sandwiched between a top thin doped copper layer and a bottom thin doped copper layer. The top and bottom thin doped copper layers produce a higher electromigration resistance. The pure copper layer produces a relatively low resistivity.
Inventors
- 👤 Jiang Tao
- 👤 Peng Fang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:02
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/40; H10W20/41; H10W20/44; H10W20/4403; H10W20/4421; H10W20/01; H10W20/031; Y; Y10; Y10S; Y10S438/00; Y10S438/927
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
102 words
A method for fabricating a metallization stack structure used in ultra large-scale-integration interconnects which has a higher electromigration resistance than aluminum-based alloys and which has a lower resistivity than the aluminum-based alloys, said method comprising the steps of: providing a bottom doped copper layer; forming a pure copper layer so as to overlie said bottom doped copper layer; forming a top doped copper layer so as to overlie said pure copper layer; and said top and bottom doped copper layers producing a higher electromigration resistance than the aluminum-based alloys and said pure copper layer producing a lower resistivity than the aluminum-based alloys.
Claim 2
Independent Claim
102 words
A method for fabricating a metallization stack structure used in ultra large-scale-integration interconnects which has a higher electromigration resistance than aluminum-based alloys and which has a lower resistivity than the aluminum-based alloys, said method comprising the steps of: providing a bottom doped copper layer; forming a pure copper layer so as to overlie said bottom doped copper layer; forming a top doped copper layer so as to overlie said pure copper layer; and said top and bottom doped copper layers producing a higher electromigration resistance than the aluminum-based alloys and said pure copper layer producing a lower resistivity than the aluminum-based alloys.
Claim 3
Dependent Claim
25 words
A method for fabricating a metallization stack structure as claimed in claim 1, wherein the step of providing the bottom layer utilizes a sputtering process.
Claim 4
Dependent Claim
36 words
A method for fabricating a metallization stack structure as claimed in claim 2, wherein said bottom doped copper layer includes a dopant selected from the group consisting of palladium, nickel, zirconium, tantalum, aluminum, chromium, and titanium.
Claim 5
Dependent Claim
18 words
A method for fabricating a metallization stack structure as claimed in claim 3, wherein said dopant is palladium.
Claim 6
Dependent Claim
26 words
A method for fabricating a metallization stack structure as claimed in claim 4, wherein said bottom layer has a thickness in the range of 50-2,000 Å.
Claim 7
Dependent Claim
27 words
A method for fabricating a metallization stack structure as claimed in claim 5, wherein the step of forming the top layer is comprised of a sputtering process.
Claim 8
Dependent Claim
36 words
A method for fabricating a metallization stack structure as claimed in claim 6, wherein said top doped copper layer includes a dopant selected from the group consisting of palladium, nickel, zirconium, tantalum, aluminum, chromium, and titanium.
Claim 9
Dependent Claim
18 words
A method for fabricating a metallization stack structure as claimed in claim 7, wherein said dopant is palladium.
Claim 10
Dependent Claim
26 words
A method for fabricating a metallization stack structure as claimed in claim 8, wherein said bottom layer has a thickness in the range of 50-2,000 Å.
Claim 11
Dependent Claim
30 words
A method for fabricating a metallization stack structure as claimed in claim 9, wherein said pure copper layer has a thickness in the range of 0.2 μm to 2 μm.
Claim 12
Dependent Claim
25 words
A method for fabricating a metallization stack structure as claimed in claim 1, wherein the step of providing the bottom layer utilizes chemical vapor deposition.
Claim 13
Dependent Claim
25 words
A method for fabricating a metallization stack structure as claimed in claim 1, wherein the step of providing the bottom layer utilizes plasma vapor deposition.
References Cited (Backward Citations)
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JPH05102155A
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JPH05267299A
Cited
US5719447A
Cited
US5391517A
Cited
US5656860A
Cited
US5545927A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-04-05 | 2002-10-05 | 2003-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-04-05 | 2006-10-05 | 2007-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-04-05 | 2010-10-05 | 2011-04-06 | $7700.00 | Window Closed / Lapsed |