US4495221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable rate semiconductor deposition process
Assignee: Signetics Corp
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Filing: 1982-10-26
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Granted: 1985-01-22
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Expires: 2002-10-26
Abstract
Abstract A layer of a conductive material consisting of aluminum alone or in combination with a small percentage of copper and/or silicon is formed on a semiconductor surface in a two-step deposition process in such a manner as to largely avoid serious continuity defects in the layer.
Inventors
- 👤 Eliot K. Broadbent
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 01:27
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/40; H10P14/412; C; C23; C23C; C23C14/00; C23C14/22; C23C14/24; H10P14/42; H10P14/44; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/062
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
186 words
A method of forming a layer of an electically conductive material on a surface of a semiconductor body wherein the material substantially consists of aluminum with no more than 4% by weight of copper and no more than 4% by weight of silicon, characterized by the steps of: initially directing atoms of the material toward the surface to accumulate there at a potentially variable first deposition rate whose average value R 1AVG is not greater than 10 angstroms/second on substantially non-inclined portions of the surface and is sufficiently less than the average value R 2AVG of a potentially variable second deposition rate that I 1AVG /R 1AVG is not greater than one half I 2AVG /R 2AVG where I AVG and I 2AVG are the average nucleation rates of atoms of the material on the non-inclined portions at the first and second deposition rates, respectively; and subsequently directing atoms of the material toward the surface at the second deposition rate to increase the average thickness of the layer to a selected thickness, the temperature of the body being largely the same during both steps of directing.
Claim 2
Independent Claim
186 words
A method of forming a layer of an electically conductive material on a surface of a semiconductor body wherein the material substantially consists of aluminum with no more than 4% by weight of copper and no more than 4% by weight of silicon, characterized by the steps of: initially directing atoms of the material toward the surface to accumulate there at a potentially variable first deposition rate whose average value R 1AVG is not greater than 10 angstroms/second on substantially non-inclined portions of the surface and is sufficiently less than the average value R 2AVG of a potentially variable second deposition rate that I 1AVG /R 1AVG is not greater than one half I 2AVG /R 2AVG where I AVG and I 2AVG are the average nucleation rates of atoms of the material on the non-inclined portions at the first and second deposition rates, respectively; and subsequently directing atoms of the material toward the surface at the second deposition rate to increase the average thickness of the layer to a selected thickness, the temperature of the body being largely the same during both steps of directing.
Claim 3
Dependent Claim
34 words
A method as in claim 1 characterized in that the steps of directing are performed by evaporative deposition with the temperature of the body being in the range of room temperature to 400° C.
Claim 4
Dependent Claim
47 words
A method as in claim 2 wherein the surface has a step profile, characterized in that the ratio of the average thickness of the material formed on the non-inclined portion during the step of initially directing to the height of the step profile is at least 0.25.
Claim 5
Dependent Claim
16 words
A method as in claim 3 characterized in that said ratio is not greater than 0.5.
Claim 6
Dependent Claim
32 words
A method as in claim 2 characterized in that the average thickness of the material formed on the non-inclined portions during the step of initally directing is not less than 2,000 angstroms.
Claim 7
Dependent Claim
32 words
A method as in claim 5 characterized in that the average thickness of the material formed on the non-inclined portions during the step of initially directing is not greater than 4,000 angstroms.
Claim 8
Dependent Claim
24 words
A method as in claim 6 characterized in that I 1AVG /R 2AVG is not greater than one third I 2AVG /R 2AVG .
Claim 9
Dependent Claim
21 words
A method as in claim 2 characterized in that R 1AVG on the non-inclined portions is not less than 2 angstroms/second.
Claim 10
Dependent Claim
24 words
A method as in claim 2 characterized in that R 1AVG on the non-inclined portions is in the range of 4 to 6 angstroms/second.
Claim 11
Dependent Claim
132 words
A method as in claim 2 wherein the surface has inclined surface portions that each have a topographical surface angle μ whose absolute value is not greater than 90°+θ MAX where θ MAX is the maximum value of the impingement angle relative to a perpendicular to any of the non-inclined surface portions at which atoms of the material are directed, characterized in that adatom migration of atoms of the material across the surface is sufficiently dominant over nucleation growth of the material on the surface at the first deposition rate compared to the second deposition rate that continuity defects in the thickness of the material accumulated on the inclined portions that would otherwise result during the step of initially directing if it were performed at the second deposition rate are substantially reduced.
References Cited (Backward Citations)
US3934059A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-01-22 | 1988-07-23 | 1989-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-22 | 1992-07-23 | 1993-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-22 | 1996-07-23 | 1997-01-22 | $7700.00 | Window Closed / Lapsed |