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Patent US5071791A successfully refreshed from Google Patents.
US5071791A
Expired / Lapsed
US
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Method for forming metal layer
Assignee: Fujitsu Semiconductor Ltd
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Filing: 1991-02-08
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Granted: 1991-12-10
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Expires: 2011-02-08
Abstract
Abstract A method for forming a metal layer includes the steps of forming an insulation layer having at least one step portion on a wafer; and forming the metal layer over the insulation layer. The metal layer is formed by depositing aluminum-based alloy by sputtering while the wafer is heated to a temperature higher than a predetermined temperature. As a result, at the step portion, a good step coverage can be obtained and the surface of the metal layer can be planarized. At the same time, the method according to the present invention contributes to a prevention of deterioration in the quality of the layer and facilitates a process to be carried out at a later stage.
Inventors
- 👤 Minoru Inoue
- 👤 Kouzi Hashizume
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:59
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/40; H10W20/41; H10W20/44; H10W20/4403; H10W20/4405; H10W20/4407; H10P; H10P14/00; H10P14/40; H10P14/412; C; C23; C23C; C23C14/00; C23C14/22; C23C14/34; H10P14/42; H10P14/44; H10W20/01; H10W20/031
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
101 words
A method for forming a metal layer by depositing aluminum-based alloy on a wafer by sputtering, said method comprising the steps of: (a) forming an insulation layer having at least one step portion on the wafer; (b) forming the metal layer by sputter depositing the aluminum-based alloy including an impurity containing admixture over the insulation layer while heating the wafer to a temperature higher than a predetermined temperature at which a solid solution including aluminum and aluminum-based alloy is formed in the aluminum-based alloy; and (c) freezing the wafer at a rate such that the impurity containing admixture does not precipitate.
Claim 2
Independent Claim
101 words
A method for forming a metal layer by depositing aluminum-based alloy on a wafer by sputtering, said method comprising the steps of: (a) forming an insulation layer having at least one step portion on the wafer; (b) forming the metal layer by sputter depositing the aluminum-based alloy including an impurity containing admixture over the insulation layer while heating the wafer to a temperature higher than a predetermined temperature at which a solid solution including aluminum and aluminum-based alloy is formed in the aluminum-based alloy; and (c) freezing the wafer at a rate such that the impurity containing admixture does not precipitate.
Claim 3
Dependent Claim
36 words
A method as set forth in claim 1, wherein the predetermined temperature in said step b) is set to a lower limit of a temperature range sufficient for forming the solid solution in the aluminum-based alloy.
Claim 4
Dependent Claim
37 words
A method as set forth in claim 2, wherein the lower limit value is approximately 525° C., and wherein the aluminum-based alloy in said step b) is a binary alloy containing 1 percent by weight of silicon.
Claim 5
Dependent Claim
44 words
A method as set forth in claim 3, wherein said step b) comprises the substep of heating the wafer to at least 525° C. by heat produced from a heating means and heat generated due to a deposition of aluminum atoms on the wafer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-12-09 | 1995-06-10 | 1995-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-09 | 1999-06-10 | 1999-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-09 | 2003-06-10 | 2003-12-10 | $7700.00 | Window Closed / Lapsed |