US5494840A
Expired / Lapsed
US
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Method for manufacturing DRAM memory cells having a thin metal oxide film on a thin metal film
Assignee: Foundation for Advancement of International Science
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Filing: 1991-12-27
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Granted: 1996-02-27
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Expires: 2011-12-27
Abstract
Abstract A method for manufacturing memory cells of a DRAM, which are manufactured easily with a high yield, and have high breakdown voltages and large capacitance. In the method, after forming a metallic thin film comprising at least one layer on a substrate, the surface of the metallic thin film is directly oxidized, and a thin film of a metallic oxide is formed on the surface of the metallic thin film.
Inventors
- 👤 Tadahiro Ohmi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:27
CPC Classifications
H; H10; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/033; H10B12/30; H10D; H10D1/00; H10D1/60; H10D1/68; H10P; H10P14/00; H10P14/60; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6314; H10P14/6322; H10P14/69; H10P14/692; H10P14/6938; H10P14/6939; H10P14/69393
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
164 words
A method for manufacturing memory cells of a DRAM, wherein said method comprises: a first process, in which a first region having an opposite conductive type from that of a substrate is formed, and a surface of said first region of said substrate, which surface is covered with an insulation film, is exposed, a second process, in which a metal film comprising at least one layer is formed, a third process, in which a metal oxide film is formed on a surface of said metal film by means of direct oxidation of said surface of said metal film which is conducted by means of supplying oxygen gas to a surface of said metal film, and by irradiating said surface with inert gas ions having a kinetic energy of 90 ev or below, a fourth process, in which a conductive film comprising at least one layer is formed, and a fifth process, in which wiring lines are formed after formation of an interlayer insulation film.
Claim 2
Independent Claim
164 words
A method for manufacturing memory cells of a DRAM, wherein said method comprises: a first process, in which a first region having an opposite conductive type from that of a substrate is formed, and a surface of said first region of said substrate, which surface is covered with an insulation film, is exposed, a second process, in which a metal film comprising at least one layer is formed, a third process, in which a metal oxide film is formed on a surface of said metal film by means of direct oxidation of said surface of said metal film which is conducted by means of supplying oxygen gas to a surface of said metal film, and by irradiating said surface with inert gas ions having a kinetic energy of 90 ev or below, a fourth process, in which a conductive film comprising at least one layer is formed, and a fifth process, in which wiring lines are formed after formation of an interlayer insulation film.
Claim 3
Dependent Claim
36 words
A method for manufacturing memory cells of a DRAM in accordance with claim 1, wherein said second process and said third process are consecutively conducted in a single vacuum chamber without disruption of a vacuum thereof.
Claim 4
Dependent Claim
38 words
A method for manufacturing memory cells of DRAM in accordance with claim 2, wherein said second process, said third process, and said fourth process are consecutively conducted in a single vacuum chamber without disruption of a vacuum thereof.
Claim 5
Dependent Claim
41 words
A method for manufacturing memory cells of DRAM in accordance with claim 3, wherein said first process, said second process, said third process, and said fourth process are consecutively conducted in a single vacuum chamber without disruption of a vacuum thereof.
Claim 6
Dependent Claim
49 words
A method for manufacturing memory cells of DRAM in accordance with claim 1, wherein transportation of a substrate between said second process and said third process is conducted in an inert gas atmosphere or in a highly pure air atmosphere having a moisture concentration of 10 ppb or below.
Claim 7
Dependent Claim
55 words
A method for manufacturing memory cells of a DRAM in accordance with claim 5, wherein transportation of a substrate between said second process, said third process, and said fourth process is conducted in an atmosphere of an inert gas or in an highly purified air atmosphere having a moisture concentration of 10 ppb or below.
Claim 8
Dependent Claim
57 words
A method for manufacturing memory cells of DRAM in accordance with claim 6, wherein transportation of a substrate between said first process, said second process, said third process, and said fourth process is conducted in a atmosphere of an inert gas or in a highly purified air atmosphere having a moisture concentration of 10 ppb or below.
Claim 9
Dependent Claim
26 words
A method for manufacturing memory cells of a DRAM in accordance with claim 1, wherein said metal film and said conductive film comprise an identical material.
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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) | 1999-02-26 | 1999-08-28 | 2000-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-02-26 | 2003-08-28 | 2004-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-02-26 | 2007-08-28 | 2008-02-27 | $7700.00 | Window Closed / Lapsed |