US3830657A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making integrated circuit contact structure
Assignee: International Business Machines Corp
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Filing: 1971-06-30
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Granted: 1974-08-20
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Expires: 1991-06-30
Abstract
Abstract An electrical interconnection contact structure including a layer containing a major proportion of an intermetallic compound contacting the surface of an integrated circuit device. The intermetallic layer is covered by a layer of conductive alloy which includes a major proportion of a solid solution of the same chemical elements as the intermetallic compound. One of the chemical elements is preferred to be an electromigration preventing dopant. Two methods of creating such a contact structure are disclosed including a sandwich technique where a layer of a first element and a layer of a second element form the intermetallic compound and a co-deposition technique where the first and second elements are co-deposited as the intermetallic compound. An alternative embodiment includes causing the intermetallic layer to spheroidize after exposure to high temperature stress allowing the major ingredient of the overlying layer to contact the semiconductor surface between spheroids. The invention provides an effective method of controlling spiking of shallow semiconductor junctions while improving the electromigration characteristics of the conductive member.
Inventors
- 👤 P Farrar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:44
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/40; H10W20/41; H10W20/425; H10P; H10P95/00; Y; Y10; Y10S; Y10S438/00; Y10S438/927
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
21 words
The method of claim 1 wherein said first and second metals are sequentially deposited on the surface of said semiconductor device.
Claim 2
Dependent Claim
26 words
The method of claim 2 wherein said second metal is deposited prior to the deposition of said first metal on the surface of said semiconductor device.
Claim 3
Dependent Claim
11 words
The method of claim 2 wherein said second metal is copper.
Claim 4
Independent Claim
96 words
The method of making interconnection metallurgy for contacting the surface of a silicon semiconductor device, comprising the steps of: co-depositing aluminum and an element selected from the group consisting of chromium, copper, and iron to form a first layer on the surface of said semiconductor device of an intermetallic compound to provide a diffusion barrier to silicon, and then depositing a second layer of conductive material on said first layer, and second layer being of a different composition than said first layer and comprising a substantial portion of aluminum and a minor portion of said element.
Claim 5
Dependent Claim
60 words
The method of claim 5 wherein said element is copper and said first layer is about 1,000 to 2,000 angstrom units thick and further including the additional step of: heating the resulting structure to a temperature in excess of 200*C to cause said intermetallic compound to spheriodize discontinuously causing said second layer to contact the surface of said semiconductor device.
Claim 6
Dependent Claim
10 words
The method of claim 5 whereIn said element is copper.
Claim 7
Independent Claim
200 words
A method of providing an intermetallic diffusion barrier to prevent spiking of metallic contact members into shallow diffusion areas on the surface of a partially dielectric-masked silicon semiconductor device during high temperature processing steps subsequent to applying said contact member, while maintaining improved electromigration properties of said contact member and while further maintaining a desired work function between said contact member and the contacted surface of said semiconductor device, comprising the steps of: providing a thin continuous layer of an intermetallic compound phase material on the surface of said silicon semiconductor device, said intermetallic compound comprising aluminum and a metal selected from the group consisting of chromium, copper, and iron; providing a conductive layer of aluminum containing said metal to provide a total amount of said metal in said intermetallic and said conductive layers equal to a predetermined total percentage known to improve the electromigration properties of said contact member; and exposing said semiconductor structure to a high temperature process for a sufficient period of time to spheroidize said intermetallic layer causing said layer to become discontinuous and allowing said conductive layer to contact portioNs of the surface of said semiconductor device which are not covered by said discontinuous layer.
Claim 8
Dependent Claim
10 words
The method of claim 8 wherein said metal is copper.
Claim 9
Dependent Claim
21 words
The method of claim 9 wherein said layer of intermetallic compound phase material is about 1,000 to 2,000 angstrom units thick.
Claim 10
Independent Claim
190 words
A method of providing an intermetallic diffusion barrier to prevent spiking of metallic contact members into shallow diffusion areas on the surface of a partially dielectric-masked silicon semiconductor device during high temperature processing steps subsequent to applying said contact member, while maintaining improved electromigration properties of said contact member and while further maintaining a desired work function between said contact member and the contact surface of said semiconductor device, comprising the steps of: providing a thin continuous layer of an intermetallic compound phase material on the surface of said silicon semiconductor device, said intermetallic compound comprising aluminum and copper and having the formula Al2Cu; providing a conductive layer of aluminum containing copper on said continuous layer, a total amount of copper in said intermetallic and conductive layers equal to a predetermined total percentage known to improve the electromigration properties of said contact member; and exposing said semiconductor structure to a high temperature process for a sufficient period of time to spheroidize said intermetallic layer causing said layer to become discontinuous and to allow said conductive layer to contact the surface of said semiconductor device through discontinuities in said intermetallic layer.
Claim 11
Dependent Claim
23 words
The method of claim 11 wherein the total amount of copper in said intermetallic and said conductive layers equals about 15 weight percent.
Claim 12
Independent Claim
104 words
The method of making a conductive metallurgical member for contacting a predetermined area of the surface of a silicon semiconductor device, comprising the steps of: depositing aluminum and copper over said predetermined area of said semiconductor device, the proportions of aluminum and copper being in a ratio to form the intermetallic compound Al2Cu to act as a diffusion barrier to silicon; causing said aluminum and copper to substantially come to equilibrium to form an alloy layer comprising said intermetallic compound; and depositing a continuous metallic layer on said alloy layer, said continuous metallic layer substantially comprising a solid solution phase of copper in aluminum.
Claim 13
Dependent Claim
18 words
The method of claim 13 wherein the amount of copper in said member is about 15 weight percent.
Claim 14
Independent Claim
88 words
The method of making interconnection metallurgy for contacting the surface of a silicon semiconductor device, comprising the steps of: co-depositing aluminum and copper in a stoichiometric ratio to form a first layer of the intermetallic compound Al2Cu on the surface of said semiconductor device to provide a diffusion barrier to silicon; and depositing a second layer of conductive material on said first layer, said second layer being of a different composition than said first layer and comprising a substantial portion of aluminum and a minor portion of copper.
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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) | 1977-08-19 | 1978-02-18 | 1978-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-19 | 1982-02-18 | 1982-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-19 | 1986-02-18 | 1986-08-20 | $7700.00 | Window Closed / Lapsed |