US4499119A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing super-conductive tunnel junction devices with precise junction area control
Assignee: Unisys Corp
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Filing: 1983-07-06
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Granted: 1985-02-12
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Expires: 2003-07-06
Abstract
Abstract Superconductive tunnel junctions are manufactured with precise junction areas by defining a narrow-line junction of precise width utilizing a narrow-line mask of precise width and thereafter applying a second narrow-line mask of precise width at an angle to the narrow-line junction to define a junction area with dimensions precisely controlled by the widths of the narrow-line masks. "Edge lithography" is preferably utilized to provide the narrow-line masks.
Inventors
- 👤 Lawrence N. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 02:10
CPC Classifications
H; H10; H10N; H10N60/00; H10N60/01; H10N60/0912; Y; Y10; Y10S; Y10S505/00; Y10S505/80; Y10S505/815; Y10S505/818; Y10S505/82
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
89 words
A method of defining an area on a layer of an integrated circuit comprising the steps of masking a first region of said layer with a said first narrow-line mask, subtractively rendering ineffective unmasked regions of said layer, removing said first mask, applying a second narrow-line mask to said layer intersecting said first region at an angle with respect thereto, and subtractively rendering ineffective unmasked and effective regions of said layer, so as to define said area on said layer by the intersection of said first and second masks.
Claim 2
Independent Claim
89 words
A method of defining an area on a layer of an integrated circuit comprising the steps of masking a first region of said layer with a said first narrow-line mask, subtractively rendering ineffective unmasked regions of said layer, removing said first mask, applying a second narrow-line mask to said layer intersecting said first region at an angle with respect thereto, and subtractively rendering ineffective unmasked and effective regions of said layer, so as to define said area on said layer by the intersection of said first and second masks.
Claim 3
Dependent Claim
44 words
The method of claim 1 in which said layer comprises a layer of superconductive material and said step of subtractively rendering ineffective comprises the step of converting unmasked regions of said layer of superconductive material to an insulating material through the entire thickness thereof.
Claim 4
Independent Claim
137 words
A method of defining the area of a superconductive tunnel junction comprising the steps of forming a first layer of superconductive material on a substrate, forming a barrier layer of barrier material on said first layer, forming a second layer of superconductive material on said barrier layer, masking a first region of said second layer with a first narrow-line mask, converting unmasked regions of said second layer of superconductive material to an insulating material through the entire thickness thereof, removing said first mask, applying a second narrow-line mask to said second layer intersecting said first region at an angle with respect thereto, and converting unmasked and unconverted regions of said second layer of superconductive material to an insulating material through the entire thickness thereof, said first layer remaining substantially unconverted to insulating material during said conversion steps.
Claim 5
Independent Claim
137 words
A method of defining the area of a superconductive tunnel junction comprising the steps of forming a first layer of superconductive material on a substrate, forming a barrier layer of barrier material on said first layer, forming a second layer of superconductive material on said barrier layer, masking a first region of said second layer with a first narrow-line mask, converting unmasked regions of said second layer of superconductive material to an insulating material through the entire thickness thereof, removing said first mask, applying a second narrow-line mask to said second layer intersecting said first region at an angle with respect thereto, and converting unmasked and unconverted regions of said second layer of superconductive material to an insulating material through the entire thickness thereof, said first layer remaining substantially unconverted to insulating material during said conversion steps.
Claim 6
Dependent Claim
51 words
The method of claim 3 in which said masking step comprises the steps of forming a layer of masking material on said second layer, forming a narrow-line metal mask on said layer of masking material, and transferring said metal mask to said layer of masking material to provide said narrow-line mask.
Claim 7
Dependent Claim
12 words
The method of claim 4 in which said masking material comprises insulation.
Claim 8
Dependent Claim
12 words
The method of claim 5 in which said insulation comprises silicon dioxide.
Claim 9
Dependent Claim
126 words
The method of claim 3 in which said masking step comprises the steps of forming a layer of masking material on said second layer of superconductive material, forming a step in said layer of masking material, depositing a layer of metal on said layer of masking material at an oblique angle to the normal of said layer of masking material to cover the step therein so as to form a narrow line metal mask at the vertical wall of said step, removing the flat regions of said layer of metal leaving said narrow line metal mask at said step edge, removing said layer of masking material not covered by said narrow line metal mask, and removing said narrow line metal mask from said covered masking material.
Claim 10
Dependent Claim
12 words
The method of claim 7 in which said masking material comprises insulation.
Claim 11
Dependent Claim
12 words
The method of claim 8 in which said insulation comprises silicon dioxide.
Claim 12
Dependent Claim
24 words
The method of claim 7 in which said step of forming a step in said layer of masking material comprises etching said step therein.
Claim 13
Dependent Claim
13 words
The method of claim 10 in which said etching comprises reactive sputter etching.
Claim 14
Dependent Claim
57 words
The method of claim 7 in which said step of depositing a layer of metal comprises depositing said metal at said oblique angle so that said step edge is covered to a width equal to the sine of said oblique angle times the thickness said layer of metal would have were said oblique angle equal to zero.
Claim 15
Dependent Claim
33 words
The method of claim 12 in which said step of removing said metal from said flat regions comprises removing said metal by an anisotropic etch so that said width is not substantially altered.
Claim 16
Dependent Claim
13 words
The method of claim 13 in which said anisotropic etch comprises ion milling.
Claim 17
Dependent Claim
23 words
The method of claim 7 in which said step of removing said masking material comprises removing said masking material by reactive sputter etching.
Claim 18
Dependent Claim
24 words
The method of claim 7 in which said step of removing said narrow-line metal mask comprises removing said narrow-line metal mask by selective etching.
Claim 19
Dependent Claim
138 words
The method of claim 3 in which said masking step comprises the steps of forming a layer of masking material on said second layer of superconductive material, forming a shadowing layer with respect to said layer of masking material to provide a shadowing step, depositing a layer of metal on said shadowing layer and said layer of masking material at an angle substantially normal to said layer of masking material, anisotropically etching said layer of metal at an oblique angle to the normal of said layer of masking material so that said shadowing steps shadows said layer of metal to form a narrow-line metal mask at said shadowing step, removing said shadowing layer, removing said layer of masking material not covered by said narrow-line metal mask, and removing said narrow line metal mask from said covered masking material.
Claim 20
Dependent Claim
12 words
The method of claim 17 in which said masking material comprises insulation.
Claim 21
Dependent Claim
12 words
The method of claim 18 iun which said insulation comprises silicon dioxide.
Claim 22
Dependent Claim
13 words
The method of claim 17 in which said shadowing layer comprises photoresistive material.
Claim 23
Dependent Claim
12 words
The method of claim 20 in which said photoresistive material comprises polyimide.
Claim 24
Dependent Claim
13 words
The method of claim 17 in which said anisotropic etch comprises ion milling.
Claim 25
Dependent Claim
28 words
The method of claim 17 in which the width of said narrow-line metal mask comprises the thickness of said shadowing layer times the tangent of said oblique angle.
Claim 26
Dependent Claim
107 words
The method of claim 3 in which said masking step comprises the steps of forming a layer of masking material on said second layer of superconductive material, depositing a layer of metal on said layer of masking material, forming a protective layer on said layer of metal, forming a step in said metal and protective layers leaving an exposed metal edge, oxidizing said edge of said layer of metal to form a narrow-line etch mask, removing said protective layer and said layer of metal not converted to said etch mask, removing said layer of masking material not covered by said etch mask, and removing said etch mask.
Claim 27
Dependent Claim
12 words
The method of claim 24 in which said masking material comprises insulation.
Claim 28
Dependent Claim
12 words
The method of claim 25 in which said insulation comprises silicon dioxide.
Claim 29
Dependent Claim
18 words
The method of claim 24 in which said metal comprises niobium and said etch mask comprises niobium oxide.
Claim 30
Dependent Claim
12 words
The method of claim 24 in which said protective layer comprises insulation.
Claim 31
Dependent Claim
12 words
The method of claim 28 in which said insulation comprises silicon dioxide.
Claim 32
Dependent Claim
11 words
The method of claim 24 in which said oxidation comprises anodization.
Claim 33
Dependent Claim
100 words
The method of claim 3 in which said masking step comprises the steps of forming a layer of masking material on said second layer of superconductive material, depositing a layer of metal on said layer of masking material, forming a protective layer on said layer of metal, forming a step in said metal and protective layers leaving an exposed metal edge, electroplating said edge to form a narrow-line etch mask, removing said protective layer and said layer of metal leaving said etch mask, removing said layer of masking material not covered by said etch mask, and removing said etch mask.
Claim 34
Dependent Claim
42 words
The method of claim 3 in which said converting step comprises converting at least a portion of the thickness of said barrier layer to an insulating material in alignment with and underlying the converted regions of said second layer of superconductive material.
Claim 35
Dependent Claim
45 words
The method of claim 3 including the further steps of applying further narrow-line masks to said second layer and converting unmasked and unconverted regions of said second layer to an insulating material through the entire thickness thereof, thereby defining the area of said tunnel junction.
Claim 36
Dependent Claim
18 words
The method of claim 3 in which at least one of said converting steps comprises converting by anodization.
Claim 37
Dependent Claim
18 words
The method of claim 3 in which at least one of said converting steps comprises converting by oxidation.
Claim 38
Independent Claim
225 words
A method of defining the area of a superconductive tunnel junction and manufacturing a further superconductive tunnel junction comprising the steps of forming a first layer of superconductive material on a substrate, forming a barrier layer of barrier material on said first layer, forming a second layer of superconductive material on said barrier layer, masking an area of said second layer defining said further superconductive tunnel junction, protecting a predetermined section of said second layer with a protective mask, converting unmasked regions of said second layer of superconductive material to an insulating material through the entire thickness thereof, thereby manufacturing said further superconductive tunnel junction, removing said protective mask, protecting said further superconductive tunnel junction with a further protective mask, masking a first region in said predetermined section of said second layer with a first narrow-line mask, converting unmasked regions of said second layer of superconductive material to an insulating material through the entire thickness thereof, removing said first narrow-line mask, applying a second narrow-line mask to said predetermined section of said second layer intersecting said first region at an angle with respect thereto, and converting unmasked and unconverted regions of said second layer of superconductive material to an insulating material through the entire thickness thereof, thereby defining the area of said superconductive tunnel junction by the intersection of said first and second narrow-line masks.
Claim 39
Independent Claim
225 words
A method of defining the area of a superconductive tunnel junction and manufacturing a further superconductive tunnel junction comprising the steps of forming a first layer of superconductive material on a substrate, forming a barrier layer of barrier material on said first layer, forming a second layer of superconductive material on said barrier layer, masking an area of said second layer defining said further superconductive tunnel junction, protecting a predetermined section of said second layer with a protective mask, converting unmasked regions of said second layer of superconductive material to an insulating material through the entire thickness thereof, thereby manufacturing said further superconductive tunnel junction, removing said protective mask, protecting said further superconductive tunnel junction with a further protective mask, masking a first region in said predetermined section of said second layer with a first narrow-line mask, converting unmasked regions of said second layer of superconductive material to an insulating material through the entire thickness thereof, removing said first narrow-line mask, applying a second narrow-line mask to said predetermined section of said second layer intersecting said first region at an angle with respect thereto, and converting unmasked and unconverted regions of said second layer of superconductive material to an insulating material through the entire thickness thereof, thereby defining the area of said superconductive tunnel junction by the intersection of said first and second narrow-line masks.
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) | 1988-02-12 | 1988-08-13 | 1989-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-12 | 1992-08-13 | 1993-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-12 | 1996-08-13 | 1997-02-12 | $7700.00 | Window Closed / Lapsed |