US5695810A
Expired / Lapsed
US
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Use of cobalt tungsten phosphide as a barrier material for copper metallization
Assignee: Cornell Research Foundation Inc
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Filing: 1996-11-20
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Granted: 1997-12-09
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Expires: 2016-11-20
Abstract
Abstract A technique for electrolessly depositing a CoWP barrier material on to copper and electrolessly depositing copper onto a CoWP barrier material to prevent copper diffusion when forming layers and/or structures on a semiconductor wafer.
Inventors
- 👤 Valery M. Dubin
- 👤 Yosi Schacham-Diamand
- 👤 Bin Zhao
- 👤 Prahalad K. Vasudev
- 👤 Chiu H. Ting
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:35
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/074; H10W20/076; C; C23; C23C; C23C18/00; C23C18/16; C23C18/1601; C23C18/1603; C23C18/1633; C23C18/1646; C23C18/165; C23C18/1651; C23C18/1689; C23C18/31; C23C18/38; C23C18/40; C23C18/405; C23C18/48; C23C18/50; H10P; H10P14/00; H10P14/40; H10P14/46; H10W20/031; H10W20/032; H10W20/033; H10W20/037; H10W20/042; H10W20/045; H10W20/056; H10W20/057; H10W20/0425
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
54 words
A method of electrolessly depositing copper onto a barrier layer which separates said copper from another layer disposed on an opposite side of said barrier layer from said copper, comprising the steps of: depositing cobalt-tungsten-phosphide, CoWP, electrolessly on an exposed surface of said another layer to form said barrier layer; depositing said copper electrolessly.
Claim 2
Independent Claim
54 words
A method of electrolessly depositing copper onto a barrier layer which separates said copper from another layer disposed on an opposite side of said barrier layer from said copper, comprising the steps of: depositing cobalt-tungsten-phosphide, CoWP, electrolessly on an exposed surface of said another layer to form said barrier layer; depositing said copper electrolessly.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein said copper forms an interconnect structure on a semiconductor wafer.
Claim 4
Dependent Claim
14 words
The method of claim 2 wherein said copper is selectively deposited by electroless deposition.
Claim 5
Dependent Claim
36 words
The method of claim 1 wherein said CoWP layer is deposited by subjecting said exposed surface of said another layer to an electroless deposition solution comprised of cobalt and tungsten with hypophosphite as a reducing agent.
Claim 6
Dependent Claim
24 words
The method of claim 4 wherein said tungsten in said electroless deposition solution is in the range of 2-7 percent by atomic weight percentage.
Claim 7
Independent Claim
39 words
A method of electrolessly depositing a barrier layer on copper, comprising the steps of: depositing said copper to form a copper layer; depositing cobalt-tungsten-phosphide, CoWP, electrolessly on an exposed surface of said copper layer to form said barrier layer.
Claim 8
Independent Claim
39 words
A method of electrolessly depositing a barrier layer on copper, comprising the steps of: depositing said copper to form a copper layer; depositing cobalt-tungsten-phosphide, CoWP, electrolessly on an exposed surface of said copper layer to form said barrier layer.
Claim 9
Dependent Claim
17 words
The method of claim 6 wherein said copper layer forms an interconnect structure on a semiconductor wafer.
Claim 10
Dependent Claim
14 words
The method of claim 7 wherein said copper is selectively deposited by electroless deposition.
Claim 11
Dependent Claim
37 words
The method of claim 6 wherein said CoWP barrier layer is deposited by subjecting said exposed surface of said copper layer to an electroless deposition solution comprised of cobalt and tungsten with hypophosphite as a reducing agent.
Claim 12
Dependent Claim
24 words
The method of claim 9 wherein said tungsten in said electroless deposition solution is in the range of 2-7 percent by atomic weight percentage.
Claim 13
Independent Claim
61 words
A method of electrolessly depositing a diffusion barrier layer on a material layer, comprising the steps of: activating a surface of said material layer for autocatalytic growth of cobalt-tungsten-phosphide, (CoWP), by forming an activation seed layer for CoWP on said surface of said material layer; depositing CoWP electrolessly on said surface of said material layer to form said diffusion barrier layer.
Claim 14
Independent Claim
61 words
A method of electrolessly depositing a diffusion barrier layer on a material layer, comprising the steps of: activating a surface of said material layer for autocatalytic growth of cobalt-tungsten-phosphide, (CoWP), by forming an activation seed layer for CoWP on said surface of said material layer; depositing CoWP electrolessly on said surface of said material layer to form said diffusion barrier layer.
Claim 15
Dependent Claim
15 words
The method of claim 11 wherein said material layer is formed from a dielectric material.
Claim 16
Dependent Claim
22 words
The method of claim 12 wherein said seed layer is formed by depositing cobalt, tungsten, palladium or platinum on said dielectric material.
Claim 17
Dependent Claim
19 words
The method of claim 13 further including the step of electrolessly depositing copper onto said CoWP diffusion barrier layer.
Claim 18
Dependent Claim
37 words
The method of claim 11 wherein said CoWP diffusion barrier layer is deposited by subjecting said surface of said material layer to an electroless deposition solution comprised of cobalt and tungsten with hypophosphite as a reducing agent.
Claim 19
Dependent Claim
24 words
The method of claim 15 wherein said tungsten in said electroless deposition solution is in the range of 2-7 percent by atomic weight percentage.
Claim 20
Independent Claim
66 words
A method of electrolessly depositing a diffusion barrier layer on a conductive layer formed on a semiconductor wafer in order to prevent diffusion of atoms between said conductive layer and a subsequent layer deposited onto said diffusion barrier layer, comprising the steps of: depositing cobalt-tungsten-phosphide, CoWP, electrolessly on said conductive layer to form said diffusion barrier layer; depositing said subsequent layer over said diffusion barrier layer.
Claim 21
Independent Claim
66 words
A method of electrolessly depositing a diffusion barrier layer on a conductive layer formed on a semiconductor wafer in order to prevent diffusion of atoms between said conductive layer and a subsequent layer deposited onto said diffusion barrier layer, comprising the steps of: depositing cobalt-tungsten-phosphide, CoWP, electrolessly on said conductive layer to form said diffusion barrier layer; depositing said subsequent layer over said diffusion barrier layer.
Claim 22
Dependent Claim
16 words
The method of claim 17 wherein said conductive layer is catalytic to electroless deposition of CoWP.
Claim 23
Dependent Claim
17 words
The method of claim 18 wherein said conductive layer is comprised of copper or a copper alloy.
Claim 24
Dependent Claim
37 words
The method of claim 19 wherein said CoWP diffusion barrier layer is deposited by subjecting said surface of said conductive layer to an electroless deposition solution comprised of cobalt and tungsten with hypophosphite as a reducing agent.
Claim 25
Dependent Claim
24 words
The method of claim 20 wherein said tungsten in said electroless deposition solution is in the range of 2-7 percent by atomic weight percentage.
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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) | 2000-12-08 | 2001-06-09 | 2001-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-12-08 | 2005-06-09 | 2005-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-12-08 | 2009-06-09 | 2009-12-09 | $7700.00 | Window Closed / Lapsed |