US6130156A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable doping of metal plugs for enhanced reliability
Assignee: Texas Instruments Inc
•
Filing: 1999-03-30
•
Granted: 2000-10-10
•
Expires: 2019-03-30
Abstract
Abstract A method of fabricating an interconnect wherein there is initially provided a first layer of electrically conductive interconnect (3). A via (7) is formed which is defined by walls extending to the first layer of interconnect. A layer of titanium (9) is formed between the electrically conductive interconnect and the first layer of electrically conductive metal (11). A first layer of electrically conductive metal is formed on the walls of the via having a predetermined etch rate relative to a specific etch species and a second layer of electrically conductive metal (13) is formed on the first layer of electrically conductive metal having an etch rate relative to the specific etch species greater than the first layer and which preferably extends into the via. The first layer of electrically conductive interconnect is preferably aluminum, the first layer of electrically conductive metal is preferably a metal containing from about one percent by weight to about one hundred percent copper and the rest essentially aluminum and the second layer of electrically conductive metal is preferably copper doped aluminum having a lower copper content than the first electrically conductive layer.
Inventors
- 👤 Robert H. Havemann
- 👤 Girish A. Dixit
- 👤 Stephen W. Russell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:14
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/032; H10W20/033; H10W20/042; H10W20/043; H10W20/045; H10W20/056; H10W20/064; H10W20/0425; H10W20/40; H10W20/41; H10W20/44; H10W20/4403; H10W20/4405; H10W20/4407; H10W20/4421; H10W20/4424
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
86 words
A method of fabricating an interconnect comprising the steps of: (a) providing a first layer of electrically conductive interconnect; (b) forming a via defined by walls extending to said first layer; (c) forming a first layer of electrically conductive metal on the walls of said via having a predetermined etch rate relative to a specific etch species; and (d) forming a second layer of electrically conductive metal on said first layer having an etch rate relative to said specific etch species greater than said first layer.
Claim 2
Independent Claim
86 words
A method of fabricating an interconnect comprising the steps of: (a) providing a first layer of electrically conductive interconnect; (b) forming a via defined by walls extending to said first layer; (c) forming a first layer of electrically conductive metal on the walls of said via having a predetermined etch rate relative to a specific etch species; and (d) forming a second layer of electrically conductive metal on said first layer having an etch rate relative to said specific etch species greater than said first layer.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein said second layer extends into said via.
Claim 4
Dependent Claim
32 words
The method of claim 2 further including the step of etching said first and second layers with an etchant that etches said second layer at a faster rate than said first layer.
Claim 5
Dependent Claim
28 words
The method of claim 3 further including the step of providing a layer of titanium between said electrically conductive interconnect and said first layer of electrically conductive metal.
Claim 6
Dependent Claim
67 words
The method of claim 4 wherein said first layer of electrically conductive interconnect is aluminum, said first layer of electrically conductive metal is a metal containing from about one percent by weight to one hundred percent copper and the rest, if any, essentially aluminum and said second layer of electrically conductive metal is copper doped aluminum having a lower copper content than said first electrically conductive layer.
Claim 7
Dependent Claim
26 words
The method of claim 5 further including the step of providing a third layer of electrically conductive interconnect on said second layer of electrically conductive metal.
Claim 8
Dependent Claim
26 words
The method of claim 4 further including the step of providing a third layer of electrically conductive interconnect on said second layer of electrically conductive metal.
Claim 9
Dependent Claim
67 words
The method of claim 3 wherein said first layer of electrically conductive interconnect is aluminum, said first layer of electrically conductive metal is a metal containing from about one percent by weight to one hundred percent copper and the rest, if any, essentially aluminum and said second layer of electrically conductive metal is copper doped aluminum having a lower copper content than said first electrically conductive layer.
Claim 10
Dependent Claim
26 words
The method of claim 3 further including the step of providing a third layer of electrically conductive interconnect on said second layer of electrically conductive metal.
Claim 11
Dependent Claim
28 words
The method of claim 2 further including the step of providing a layer of titanium between said electrically conductive interconnect and said first layer of electrically conductive metal.
Claim 12
Dependent Claim
67 words
The method of claim 10 wherein said first layer of electrically conductive interconnect is aluminum, said first layer of electrically conductive metal is a metal containing from about one percent by weight to one hundred percent copper and the rest, if any, essentially aluminum and said second layer of electrically conductive metal is copper doped aluminum having a lower copper content than said first electrically conductive layer.
Claim 13
Dependent Claim
67 words
The method of claim 2 wherein said first layer of electrically conductive interconnect is aluminum, said first layer of electrically conductive metal is a metal containing from about one percent by weight to one hundred percent copper and the rest, if any, essentially aluminum and said second layer of electrically conductive metal is copper doped aluminum having a lower copper content than said first electrically conductive layer.
Claim 14
Dependent Claim
32 words
The method of claim 1 further including the step of etching said first and second layers with an etchant that etches said second layer at a faster rate than said first layer.
Claim 15
Dependent Claim
28 words
The method of claim 13 further including the step of providing a layer of titanium between said electrically conductive interconnect and said first layer of electrically conductive metal.
Claim 16
Dependent Claim
67 words
The method of claim 14 wherein said first layer of electrically conductive interconnect is aluminum, said first layer of electrically conductive metal is a metal containing from about one percent by weight to one hundred percent copper and the rest, if any, essentially aluminum and said second layer of electrically conductive metal is copper doped aluminum having a lower copper content than said first electrically conductive layer.
Claim 17
Dependent Claim
67 words
The method of claim 13 wherein said first layer of electrically conductive interconnect is aluminum, said first layer of electrically conductive metal is a metal containing from about one percent by weight to one hundred percent copper and the rest, if any, essentially aluminum and said second layer of electrically conductive metal is copper doped aluminum having a lower copper content than said first electrically conductive layer.
Claim 18
Dependent Claim
28 words
The method of claim 1 further including the step of providing a layer of titanium between said electrically conductive interconnect and said first layer of electrically conductive metal.
Claim 19
Dependent Claim
67 words
The method of claim 17 wherein said first layer of electrically conductive interconnect is aluminum, said first layer of electrically conductive metal is a metal containing from about one percent by weight to one hundred percent copper and the rest, if any, essentially aluminum and said second layer of electrically conductive metal is copper doped aluminum having a lower copper content than said first electrically conductive layer.
Claim 20
Dependent Claim
67 words
The method of claim 1 wherein said first layer of electrically conductive interconnect is AlCu, said first layer of electrically conductive metal is a metal containing from about one percent by weight to one hundred percent copper and the rest, if any, essentially aluminum and said second layer of electrically conductive metal is copper doped aluminum having a lower copper content than said first electrically conductive layer.
Claim 21
Dependent Claim
26 words
The method of claim 1 further including the step of providing a third layer of electrically conductive interconnect on said second layer of electrically conductive metal.
Claim 22
Dependent Claim
74 words
The method of claim 1 wherein said first layer of electrically conductive metal is a metal containing from about 0.5 percent by weight to one hundred percent copper and the rest, if any, essentially at least one of tin and magnesium and said second layer of electrically conductive metal is copper doped with at least one of tin and magnesium in the amount of from about 0.1 to less than 100 percent by weight.
Claim 23
Dependent Claim
29 words
The method of claim 21 further including the step of forming a third layer of copper doped with at least one of tin and magnesium over said second layer.
Claim 24
Dependent Claim
19 words
The method of claim 22 wherein said first layer of electrically conductive interconnect is one of Cu or AlCu.
Claim 25
Dependent Claim
19 words
The method of claim 21 wherein said first layer of electrically conductive interconnect is one of Cu or AlCu.
Claim 26
Dependent Claim
22 words
The method of claim 1 further including the step of forming a barrier layer beneath said first layer of electrically conductive metal.
Claim 27
Dependent Claim
25 words
The method of claim 25 wherein said barrier layer is at least one of titanium nitride, tantalum, tantalum nitride, titanium silicon nitride or tungsten nitride.
Claim 28
Independent Claim
84 words
A method of fabricating an interconnect comprising the steps of: (a) providing a first layer of electrically conductive interconnect; (b) forming a via defined by walls extending to said first layer; (c) depositing a pure dopant layer on the walls of said via; (d) forming a second layer of copper or aluminum over said dopant layer which is more lightly doped than said doped layer or undoped; and (e) forming a third layer of one of doped copper or aluminum over said second layer.
Claim 29
Independent Claim
84 words
A method of fabricating an interconnect comprising the steps of: (a) providing a first layer of electrically conductive interconnect; (b) forming a via defined by walls extending to said first layer; (c) depositing a pure dopant layer on the walls of said via; (d) forming a second layer of copper or aluminum over said dopant layer which is more lightly doped than said doped layer or undoped; and (e) forming a third layer of one of doped copper or aluminum over said second layer.
Claim 30
Dependent Claim
31 words
The method of claim 27 wherein said dopant layer is formed from a material taken from the class consisting of tin or magnesium for copper doping or copper for aluminum doping.
Claim 31
Independent Claim
94 words
A method of fabricating an interconnect comprising the steps of: (a) providing a first layer of electrically conductive interconnect; (b) forming a via defined by walls extending to said first layer; (c) forming a first layer of electrically conductive metal on the walls of said via taken from the class consisting of copper for aluminum doping or tin or magnesium for copper doping; and (d) forming a second layer of electrically conductive metal on said first layer of doped or undoped copper or aluminum having a lower level of doping than said first layer.
Claim 32
Independent Claim
94 words
A method of fabricating an interconnect comprising the steps of: (a) providing a first layer of electrically conductive interconnect; (b) forming a via defined by walls extending to said first layer; (c) forming a first layer of electrically conductive metal on the walls of said via taken from the class consisting of copper for aluminum doping or tin or magnesium for copper doping; and (d) forming a second layer of electrically conductive metal on said first layer of doped or undoped copper or aluminum having a lower level of doping than said first layer.
Claim 33
Dependent Claim
13 words
The method of claim 29 wherein said second layer extends into said via.
Claim 34
Independent Claim
68 words
A method of fabricating an interconnect comprising the steps of: (a) providing a first layer of electrically conductive interconnect; (b) forming an aperture defined by walls and extending to said interconnect; (c) forming a barrier layer extending over said interconnect and said walls; and (d) forming one of a dopant layer or a doped layer of an electrically conductive metal over said barrier layer and within said aperture.
Claim 35
Independent Claim
68 words
A method of fabricating an interconnect comprising the steps of: (a) providing a first layer of electrically conductive interconnect; (b) forming an aperture defined by walls and extending to said interconnect; (c) forming a barrier layer extending over said interconnect and said walls; and (d) forming one of a dopant layer or a doped layer of an electrically conductive metal over said barrier layer and within said aperture.
Claim 36
Dependent Claim
38 words
The method of claim 31 wherein said aperture includes a trench having a first cross section over a via having a second cross section with an area less than said first cross section, said via contacting said interconnect.
Claim 37
Dependent Claim
28 words
The method of claim 31 further including forming an electricaly conductive layer over said one of a dopant layer or a doped layer of an electrically conductive metal.
Claim 38
Dependent Claim
18 words
The method of claim 33 wherein said dopant layer is tin and said electrically conductive layer is copper.
Claim 39
Dependent Claim
17 words
The method of claim 33 wherein said electrically conductive metal is a mixture of copper and tin.
Claim 40
Dependent Claim
22 words
The method of claim 34 further including the step of forming a further doped electrically conductive layer over said electrically conductive layer.
Claim 41
Dependent Claim
22 words
The method of claim 35 further including the step of forming a further doped electrically conductive layer over said electrically conductive layer.
Claim 42
Dependent Claim
22 words
The method of claim 33 further including the step of forming a further doped electrically conductive layer over said electrically conductive layer.
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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) | 2003-10-10 | 2004-04-10 | 2004-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-10-10 | 2008-04-10 | 2008-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-10-10 | 2012-04-10 | 2012-10-10 | $7700.00 | Window Closed / Lapsed |