US4984054A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric fuse for a redundancy circuit
Assignee: Mitsubishi Electric Corp
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Filing: 1990-02-20
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Granted: 1991-01-08
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Expires: 2010-02-20
Abstract
Abstract The present invention comprises a field oxide film formed on a silicon substrate, an underlying film of polycrystal silicon formed on a portion thereof and an insulating film formed so as to cover the field oxide film comprising the underlying film. A surface stepped portion of the insulating film is formed by a portion with an underlying film and a portion without an underlying film under the insulating film, and a blowout portion of a fuse is formed along the surface stepped portion. There are terminal portions at both ends of the blowout portion of the fuse and an aluminum line is connected thereto. In addition, the whole portions comprising the fuse portion are covered with another insulating film and the whole is protected. The fuse is employed as one example in a redundancy circuit of a MOS dynamic RAM having redundancy memory cells.
Inventors
- 👤 Michihiro Yamada
- 👤 Hiroshi Miyamoto
- 👤 Tadato Yamagata
- 👤 Shigeru Mori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 14:23
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/40; H10W20/49; H10W20/493
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
142 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory in a semiconductor memory, comprising: a semiconductor substrate; a first insulating film formed on a surface of said semiconductor substrate; an underlying film formed on a surface of said first insulating film; said underlying film formed between terminal portions of the electrically blowable fuse and defining a longitudinal direction; a second insulating film formed on the surface of said first insulating film and a surface of said underlying film and forming a surface stepped portion along an edge of the underlying film; and a sidewall of the surface stepped portion comprising an electrically blowable fuse material disposed in said longitudinal direction defined by said underlying film between said terminal portions of the fuse, said sidewall disposed along an edge of the surface stepped portion.
Claim 2
Dependent Claim
142 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory in a semiconductor memory, comprising: a semiconductor substrate; a first insulating film formed on a surface of said semiconductor substrate; an underlying film formed on a surface of said first insulating film; said underlying film formed between terminal portions of the electrically blowable fuse and defining a longitudinal direction; a second insulating film formed on the surface of said first insulating film and a surface of said underlying film and forming a surface stepped portion along an edge of the underlying film; and a sidewall of the surface stepped portion comprising an electrically blowable fuse material disposed in said longitudinal direction defined by said underlying film between said terminal portions of the fuse, said sidewall disposed along an edge of the surface stepped portion.
Claim 3
Dependent Claim
18 words
An electrically blowable fuse for a redundancy circuit in accordance with claim, wherein said semiconductor substrate comprises silicon.
Claim 4
Dependent Claim
20 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 2, wherein said underlying film comprises polycrystal silicon.
Claim 5
Dependent Claim
21 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 2, wherein said underlying film comprises an insulating film.
Claim 6
Dependent Claim
20 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 2, wherein said fuse material comprises polycrystal silicon.
Claim 7
Dependent Claim
20 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 2, wherein said fuse material comprises a metal.
Claim 8
Dependent Claim
30 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 2, which further comprises an overlying insulating film formed overlying said fuse material and said second insulating film.
Claim 9
Dependent Claim
33 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 7, wherein said overlying insulating film has an opening formed therein at a region of said fuse material to be blown.
Claim 10
Dependent Claim
41 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 7, wherein said overlying insulating layer has openings formed therein at opposite ends of said fuse material and further comprising metal leads contacting said fuse material through said openings.
Claim 11
Dependent Claim
59 words
An electrically blowable fuse as recited in claim 1, wherein said fuse material comprises a strip formed on said stepped portion of said second insulating film, said strip including a first portion longitudinally overlying a portion of said underlying film and a second portion along the edge of said underlying film, thereby providing a longitudinal sidewall by anisotropic etching.
Claim 12
Dependent Claim
39 words
An electrically blowable fuse as recited in claim 1, wherein said stepped portion of said second insulating film includes two longitudinally oriented edges, and wherein said fuse material sidewall is disposed along only a single one of said edges.
Claim 13
Dependent Claim
32 words
An electrically blowable fuse as recited in claim 1, wherein said sidewall and said edge of the surface stepped portion have substantially identical lengths and are substantially coextensive in said longitudinal direction.
Claim 14
Dependent Claim
129 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory, provided by the steps of: forming a first insulating film on a semiconductor substrate; forming an underlying film on a surface of said first insulating film, said underlying film formed between terminal portions of the electrically blowable fuse and defining a longitudinal direction between the terminal portions; forming a second insulating film on a surface of said first insulating film and a surface of said underlying film to establish a surface stepped portion along an edge of said underlying film; and forming, for the surface stepped portion, a sidewall of electrically blowable fuse material along an edge of said surface stepped portion in said longitudinal direction defined by said underlying film.
Claim 15
Dependent Claim
129 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory, provided by the steps of: forming a first insulating film on a semiconductor substrate; forming an underlying film on a surface of said first insulating film, said underlying film formed between terminal portions of the electrically blowable fuse and defining a longitudinal direction between the terminal portions; forming a second insulating film on a surface of said first insulating film and a surface of said underlying film to establish a surface stepped portion along an edge of said underlying film; and forming, for the surface stepped portion, a sidewall of electrically blowable fuse material along an edge of said surface stepped portion in said longitudinal direction defined by said underlying film.
Claim 16
Dependent Claim
61 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 13, wherein said step of forming said sidewall of electrically blowable fuse material comprises the steps of depositing a fuse material on said surface stepped portion, and anisotropically etching said fuse material to establish a narrow strip of said fuse material along said edge of said surface stepped portion.
Claim 17
Dependent Claim
41 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 13, wherein said fuse material is formed into said sidewall by anisotropically etching said fuse material along said edge of said surface stepped portion by a step of RIE.
Claim 18
Dependent Claim
19 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 15, wherein said semiconductor substrate comprises silicon.
Claim 19
Dependent Claim
20 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 16, wherein said underlying film comprises polycrystal silicon.
Claim 20
Dependent Claim
21 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 16, wherein said underlying film comprises an insulating film.
Claim 21
Dependent Claim
20 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 16, wherein said fuse material comprises polycrystal silicon.
Claim 22
Dependent Claim
20 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 16, wherein said fuse material comprises a metal.
Claim 23
Dependent Claim
30 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 13, which further comprises an overlying insulating film formed overlying said fuse material and said second insulating film.
Claim 24
Dependent Claim
33 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 21, wherein said overlying insulating film has an opening formed therein at a region of said fuse material to be blown.
Claim 25
Dependent Claim
39 words
An electrically blowable fuse for a redundancy circuit in accordance with claim 21, wherein said overlying insulating film has openings formed therein at opposite ends of said fuse material and metal leads contacting said fuse material through said openings.
Claim 26
Dependent Claim
137 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory in a semiconductor memory, comprising: a semiconductor substrate; an insulating layer formed on a surface of said semiconductor substrate and having a major surface; said insulating layer including a stepped portion along an edge of said major surface; said edge oriented substantially in a longitudinal direction defined between terminal portions of the fuse, and a fuse material on the major surface and having an electrically blowable fuse region disposed along an edge of said stepped portion of said insulating layer as a sidewall thereof, wherein said edge of said stepped portion of said insulating layer and said fuse material sidewall of said insulating layer are oriented substantially in said longitudinal direction defined between said terminal portions of the fuse.
Claim 27
Dependent Claim
137 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory in a semiconductor memory, comprising: a semiconductor substrate; an insulating layer formed on a surface of said semiconductor substrate and having a major surface; said insulating layer including a stepped portion along an edge of said major surface; said edge oriented substantially in a longitudinal direction defined between terminal portions of the fuse, and a fuse material on the major surface and having an electrically blowable fuse region disposed along an edge of said stepped portion of said insulating layer as a sidewall thereof, wherein said edge of said stepped portion of said insulating layer and said fuse material sidewall of said insulating layer are oriented substantially in said longitudinal direction defined between said terminal portions of the fuse.
Claim 28
Dependent Claim
36 words
An electrically blowable fuse as recited in claim 24 wherein said fuse region has a width in the range of 0.1 micron to 0.2 micron thereby reducing voltage and current requirements for blowing said fuse region.
Claim 29
Dependent Claim
151 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory in a semiconductor memory, comprising: a semiconductor substrate; an insulating layer formed on a surface of said semiconductor substrate and having a major surface; said insulating layer including a stepped portion along an edge of said major surface; said edge oriented substantially in a longitudinal direction defined between terminal portions of the fuse, and a fuse material formed on the major surface and having an electrically blowable fuse region along an edge of said stepped portion of said insulating layer as a sidewall thereof, wherein said edge of said stepped portion of said insulating layer and said fuse material sidewall of said insulating layer are oriented substantially in said longitudinal direction defined between said terminal portions of the fuse, the fuse region having a width commensurate with a thickness of the fuse material.
Claim 30
Dependent Claim
151 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory in a semiconductor memory, comprising: a semiconductor substrate; an insulating layer formed on a surface of said semiconductor substrate and having a major surface; said insulating layer including a stepped portion along an edge of said major surface; said edge oriented substantially in a longitudinal direction defined between terminal portions of the fuse, and a fuse material formed on the major surface and having an electrically blowable fuse region along an edge of said stepped portion of said insulating layer as a sidewall thereof, wherein said edge of said stepped portion of said insulating layer and said fuse material sidewall of said insulating layer are oriented substantially in said longitudinal direction defined between said terminal portions of the fuse, the fuse region having a width commensurate with a thickness of the fuse material.
Claim 31
Dependent Claim
164 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory in a semiconductor memory, comprising: a semiconductor substrate; an insulating layer formed on a surface of said semiconductor substrate and having a major surface; said insulating layer including a stepped portion along an edge of said major surface; said edge oriented substantially in a longitudinal direction defined between terminal portions of the fuse, and an electrically blowable fuse strip formed to have a width commensurate with a thickness of a fuse material by depositing the fuse material on said major surface and on said stepped portion of said insulating layer and by anisotropically etching said fuse material to establish along said stepped portion a sidewall of said fuse material, wherein said stepped portion of said insulating layer and said fuse strip sidewall of said insulating layer are disposed to have longitudinal directions oriented substantially in said longitudinal direction defined between said terminal portions of the fuse.
Claim 32
Dependent Claim
164 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory in a semiconductor memory, comprising: a semiconductor substrate; an insulating layer formed on a surface of said semiconductor substrate and having a major surface; said insulating layer including a stepped portion along an edge of said major surface; said edge oriented substantially in a longitudinal direction defined between terminal portions of the fuse, and an electrically blowable fuse strip formed to have a width commensurate with a thickness of a fuse material by depositing the fuse material on said major surface and on said stepped portion of said insulating layer and by anisotropically etching said fuse material to establish along said stepped portion a sidewall of said fuse material, wherein said stepped portion of said insulating layer and said fuse strip sidewall of said insulating layer are disposed to have longitudinal directions oriented substantially in said longitudinal direction defined between said terminal portions of the fuse.
Claim 33
Dependent Claim
117 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory in a semiconductor memory, comprising: a semiconductor substrate; an insulating layer formed on a surface of said semiconductor substrate and having a major surface including a stepped portion; a strip of an electrically blowable fuse material formed on an edge of the stepped portion of the major surface of said insulating layer; said edge of said stepped portion oriented substantially in a longitudinal direction defined between terminal portions of the fuse, and a sidewall of said insulating layer including said strip of fuse material, said sidewall oriented substantially in said longitudinal direction defined between terminal portions of the fuse.
Claim 34
Dependent Claim
117 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory in a semiconductor memory, comprising: a semiconductor substrate; an insulating layer formed on a surface of said semiconductor substrate and having a major surface including a stepped portion; a strip of an electrically blowable fuse material formed on an edge of the stepped portion of the major surface of said insulating layer; said edge of said stepped portion oriented substantially in a longitudinal direction defined between terminal portions of the fuse, and a sidewall of said insulating layer including said strip of fuse material, said sidewall oriented substantially in said longitudinal direction defined between terminal portions of the fuse.
Claim 35
Dependent Claim
38 words
An electrically blowable fuse as recited in claim 28, wherein said stepped portion of said insulating layer includes two longitudinally oriented edges, and wherein said fuse material sidewall is disposed along only a single one of said edges.
Claim 36
Dependent Claim
31 words
An electrically blowable fuse as recited in claim 29, wherein said strip of fuse material and said longitudinal edge of said stepped portion are substantially coextensive and have substantially identical lengths.
Claim 37
Dependent Claim
31 words
An electrically blowable fuse as recited in claim 28, wherein said strip of fuse material and said longitudinal edge of said stepped portion are substantially coextensive and have substantially identical lengths.
Claim 38
Dependent Claim
134 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory in a semiconductor memory comprising: a semiconductor substrate; an insulating layer formed on a surface of said semiconductor substrate and having a major surface; said insulating layer including a stepped portion along an edge of said major surface; wherein an electrically blowable fuse region is formed along an edge of said stepped portion to provide a sidewall of said stepped portion, said electrically blowable fuse region having a width substantially equal to a thickness of a strip of a fuse material including said fuse region and formed on said insulating layer, wherein said sidewall is oriented to have a longitudinal direction thereof arranged substantially in a direction defined between terminal portions of the electrically blowable fuse.
Claim 39
Dependent Claim
134 words
An electrically blowable fuse for a redundancy circuit for use in replacing defective memory cells with redundancy memory in a semiconductor memory comprising: a semiconductor substrate; an insulating layer formed on a surface of said semiconductor substrate and having a major surface; said insulating layer including a stepped portion along an edge of said major surface; wherein an electrically blowable fuse region is formed along an edge of said stepped portion to provide a sidewall of said stepped portion, said electrically blowable fuse region having a width substantially equal to a thickness of a strip of a fuse material including said fuse region and formed on said insulating layer, wherein said sidewall is oriented to have a longitudinal direction thereof arranged substantially in a direction defined between terminal portions of the electrically blowable fuse.
References Cited (Backward Citations)
JPS5228280A
Cited
US4389715A
Cited
US4723155A
Cited
US4503315A
Cited
JPS59148198A
Cited
US4774561A
Cited
US4748491A
Cited
EP0241046A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-07 | 1994-07-09 | 1995-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-07 | 1998-07-09 | 1999-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-07 | 2002-07-09 | 2003-01-08 | $7700.00 | Window Closed / Lapsed |