US5475253A
Expired / Lapsed
US
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Antifuse structure with increased breakdown at edges
Assignee: Xilinx Inc
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Filing: 1993-10-04
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Granted: 1995-12-12
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Expires: 2013-10-04
Abstract
Abstract An antifuse is provided which includes a first conductive layer, an antifuse layer formed on the first conductive layer, and a second conductive layer formed on the antifuse layer. A portion of the antifuse layer forms a substantially orthogonal angle with the first conductive layer and the second conductive layer. This "corner" formation of the antifuse enhances the electric field at this location during programming, thereby providing a predictable location for the filament, i.e. the conductive path between the first and second conductive layers. This antifuse provides other advantages including: a relatively low programming voltage, good step coverage for the antifuse layer and the upper conductive layer, a low, stable resistance value, and minimal shearing effects on the filament.
Inventors
- 👤 Kevin T. Look
- 👤 Evert A. Wolsheimer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:54
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/064; H10W20/065; H10W20/40; H10W20/49; H10W20/491; Y; Y10; Y10S; Y10S148/00; Y10S148/055
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
95 words
An antifuse comprising: a first conductive layer; a field oxide layer formed on said first conductive layer and having a via formed therein to the top surface of said first conductive layer, wherein said via includes a lower portion forming a profile perpendicular to said first conductive layer, and an upper portion forming a concave profile; an antifuse layer formed on said first conductive layer, wherein the top surface of said antifuse layer follows the contours of said lower and upper portions of said via; and a second conductive layer formed on said antifuse layer.
Claim 2
Dependent Claim
95 words
An antifuse comprising: a first conductive layer; a field oxide layer formed on said first conductive layer and having a via formed therein to the top surface of said first conductive layer, wherein said via includes a lower portion forming a profile perpendicular to said first conductive layer, and an upper portion forming a concave profile; an antifuse layer formed on said first conductive layer, wherein the top surface of said antifuse layer follows the contours of said lower and upper portions of said via; and a second conductive layer formed on said antifuse layer.
Claim 3
Dependent Claim
14 words
The antifuse of claim 1 wherein said antifuse layer includes an amorphous silicon layer.
Claim 4
Dependent Claim
19 words
The antifuse of claim 2 wherein said amorphous silicon layer has a thickness between 350 Å and 550 Å.
Claim 5
Dependent Claim
17 words
The antifuse of claim 3 wherein said amorphous silicon layer has a thickness of approximately 450 Å.
Claim 6
Dependent Claim
32 words
The antifuse of claim 2 wherein said antifuse layer further includes a first oxide layer formed on the bottom of said via between said first conductive layer and said amorphous silicon layer.
Claim 7
Dependent Claim
17 words
The antifuse of claim 5 wherein said first oxide layer is formed from said first conductive layer.
Claim 8
Dependent Claim
19 words
The antifuse of claim 5 wherein said first oxide layer has a thickness between 35 Å and 70 Å.
Claim 9
Dependent Claim
13 words
The antifuse of claim 5 wherein said first oxide layer is titanium oxide.
Claim 10
Dependent Claim
13 words
The antifuse of claim 5 wherein said first oxide layer is tungsten oxide.
Claim 11
Dependent Claim
19 words
The antifuse of claim 5 wherein said first oxide layer is a combination of titanium oxide and tungsten oxide.
Claim 12
Dependent Claim
26 words
The antifuse of claim 5 wherein said antifuse layer further includes a second oxide layer formed between said amorphous silicon layer and said second conductive layer.
Claim 13
Dependent Claim
15 words
The antifuse of claim 11 wherein said second oxide layer is a silicon dioxide layer.
Claim 14
Dependent Claim
19 words
The antifuse of claim 11 wherein said second oxide layer has a thickness between 10 Å and 30 Å.
Claim 15
Dependent Claim
21 words
The antifuse of claim 11 wherein said second oxide layer completely insulates said amorphous silicon layer from said second conductive layer.
Claim 16
Dependent Claim
18 words
The antifuse of claim 1 wherein said first conductive layer forms a lower conductive terminal of said antifuse.
Claim 17
Dependent Claim
14 words
The antifuse of claim 15 wherein said first conductive layer includes a conductive metal.
Claim 18
Dependent Claim
11 words
The antifuse of claim 16 wherein said conductive metal includes aluminum.
Claim 19
Dependent Claim
13 words
The antifuse of claim 16 wherein said conductive metal includes an aluminum-silicon alloy.
Claim 20
Dependent Claim
13 words
The antifuse of claim 16 wherein said conductive metal includes an aluminum-silicon-copper alloy.
Claim 21
Dependent Claim
11 words
The antifuse of claim 16 wherein said conductive metal includes titanium.
Claim 22
Dependent Claim
12 words
The antifuse of claim 16 wherein said conductive metal includes titanium nitride.
Claim 23
Dependent Claim
12 words
The antifuse of claim 16 wherein said conductive metal includes titanium tungsten.
Claim 24
Dependent Claim
18 words
The antifuse of claim 1 wherein said second conductive layer forms an upper conductive terminal of said antifuse.
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) | 1998-12-11 | 1999-06-12 | 1999-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-12-11 | 2003-06-12 | 2003-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-12-11 | 2007-06-12 | 2007-12-12 | $7700.00 | Window Closed / Lapsed |