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Patent US4744858A successfully refreshed from Google Patents.
US4744858A
Expired / Lapsed
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Integrated circuit metallization with reduced electromigration
Assignee: Texas Instruments Inc
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Filing: 1985-03-11
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Granted: 1988-05-17
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Expires: 2005-03-11
Abstract
Abstract The specification discloses a method and a device wherein circuit elements (10) are formed on the surface of a semiconductor body (12). A layer of oxide (22) is applied over the circuit element (10). An aperture (32) is opened through the oxide layer (22). The surface of oxide layer (22) is nonuniformly substantially roughened. A layer of metal (24) such as aluminum is formed over the oxide layer (22) and extends into the aperture (32) for contact with a portion of the device (10). The layer of metal (24) has increased granular structure and a roughened exterior surface to provide enhanced electromigration properties.
Inventors
- 👤 James M. McDavid
- 👤 Dirk N. Anderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:03
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/081; H10W20/082; H10W20/40; H10W20/41; H10W20/44; H10W20/4403; H10W20/4405; Y; Y10; Y10S; Y10S438/00; Y10S438/927; Y10S438/964
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
78 words
A method of making a semiconductor device comprising: forming circuit elements on a semiconductor surface, applying an insulating layer over said circuit elements, opening apertures in said insulating layer to selected portions of said circuit elements, nonuniformly roughening the surface of said insulating layer, and applying a layer of metal on a portion of said insulating layer extending into said apertures, said layer of metal having a granular interior and a roughened surface to provide enhanced electromigration properties.
Claim 2
Independent Claim
78 words
A method of making a semiconductor device comprising: forming circuit elements on a semiconductor surface, applying an insulating layer over said circuit elements, opening apertures in said insulating layer to selected portions of said circuit elements, nonuniformly roughening the surface of said insulating layer, and applying a layer of metal on a portion of said insulating layer extending into said apertures, said layer of metal having a granular interior and a roughened surface to provide enhanced electromigration properties.
Claim 3
Dependent Claim
42 words
The method of claim 1 wherein the surface of said insulating layer is roughened such that the vertical thickness of the surface nonuniformly varies from 300 Å to 3000 Å and the lateral feature size varies from 3000 Å to 10,000 Å.
Claim 4
Dependent Claim
13 words
The method of claim 1 wherein said step of roughening comprises plasma etching.
Claim 5
Dependent Claim
14 words
The method of claim 1 wherein said step of roughening comprises reactive ion etching.
Claim 6
Dependent Claim
13 words
The method of claim 1 wherein said step of roughening comprises acid etching.
Claim 7
Dependent Claim
20 words
The method of claim 1 wherein said step of roughening comprises applying heat to create microcracks in said insulating layer.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein said layer of metal is formed from aluminum.
Claim 9
Independent Claim
91 words
A method of forming metal contacts with improved electromigration characteristics comprising: forming circuit elements on a surface of a semiconductor body, applying layers of oxide having differing impurity doping concentrations over said circuit elements, opening apertures through said layers of oxide into contact with said circuit elements, modifying the outer surface of said oxide layers to provide substantial nonuniform variations in the thickness thereof, and applying a pattern of metal contacts over said oxide layers extending into said apertures, said metal contacts having increased grain size to provide enhanced electromigration properties.
Claim 10
Independent Claim
91 words
A method of forming metal contacts with improved electromigration characteristics comprising: forming circuit elements on a surface of a semiconductor body, applying layers of oxide having differing impurity doping concentrations over said circuit elements, opening apertures through said layers of oxide into contact with said circuit elements, modifying the outer surface of said oxide layers to provide substantial nonuniform variations in the thickness thereof, and applying a pattern of metal contacts over said oxide layers extending into said apertures, said metal contacts having increased grain size to provide enhanced electromigration properties.
Claim 11
Dependent Claim
39 words
The method of claim 8 wherein said step of modifying comprises roughening said outer surface such that the thickness nonuniformly varies between 300 Å to 3000 Å and the lateral feature size varies from 3000 Å to 10,000 Å.
Claim 12
Dependent Claim
13 words
The method of claim 8 wherein said step of modifying comprises plasma etching.
Claim 13
Dependent Claim
14 words
The method of claim 8 wherein said step of modifying comprises reactive ion etching.
Claim 14
Dependent Claim
13 words
The method of claim 8 wherein said step of modifying comprises acid etching.
Claim 15
Dependent Claim
28 words
The method of claim 8 wherein said step of modifying comprises applying heat to said layers to cause the formation of microcracks due to said differing doping concentrations.
Claim 16
Dependent Claim
11 words
The method of claim 8 wherein said impurity concentrations comprises phosphorus.
Claim 17
Dependent Claim
15 words
The method of claim 14 wherein said oxide layers include phosphorus at successively higher concentrations.
Claim 18
Dependent Claim
17 words
The method of claim 8 wherein said semiconductor body comprises silicon and said oxide comprises silicon oxide.
Claim 19
Dependent Claim
10 words
The method of claim 8 wherein said metal comprises aluminum.
References Cited (Backward Citations)
US4394406A
Cited
US4508815A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-05-17 | 1991-11-16 | 1992-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-17 | 1995-11-16 | 1996-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-17 | 1999-11-16 | 2000-05-17 | $7700.00 | Window Closed / Lapsed |