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US5494840A
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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 22:15
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.
References Cited (Backward Citations)
US4002545A
Cited
JPS5730358A
Cited
US4495219A
Cited
US4432035A
Cited
JPS62120072A
Cited
US5217914A
Cited
US5142438A
Cited
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 |