US5902690A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stray magnetic shielding for a non-volatile MRAM
Assignee: Everspin Technologies Inc
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Filing: 1997-02-25
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Granted: 1999-05-11
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Expires: 2017-02-25
Abstract
Abstract A non-volatile magneto-resistive memory positioned on a semiconductor substrate is shielded from stray magnetic fields by a passivation layer partially or completely surrounding the non-volatile magneto-resistive memory. The passivation layer includes non-conductive ferrite materials, such as Mn--Zn-Ferrite, Ni--Zn-Ferrite, MnFeO, CuFeO, FeO, or NiFeO, for shielding the non-volatile magneto-resistive memory from stray magnetic fields. The non-conductive ferrite materials may also be in the form of a layer which focuses internally generated magnetic fields on the non-volatile magneto-resistive memory to reduce power requirements.
Inventors
- 👤 Clarence J. Tracy
- 👤 Eugene Chen
- 👤 Mark Durlam
- 👤 Theodore Zhu
- 👤 Saied N. Tehrani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:53
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/02; G11C11/14; G11C11/15; H; H10; H10B; H10B61/00; H10B61/20; H10B61/22; H10W; H10W42/00; H10W42/20; H10W42/281; H10W42/287; Y; Y10; Y10S; Y10S977/00; Y10S977/70; Y10S977/832; Y10S977/838; Y10T; Y10T428/00; Y10T428/11; Y10T428/1164
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
50 words
A non-volatile magneto-resistive memory with stray magnetic shielding comprising: a non-volatile magneto-resistive memory positioned on a substrate and defining an upper surface; and a passivation layer at least partially surrounding the non-volatile magneto-resistive memory, the passivation layer including ferrite materials for shielding the non-volatile magneto-resistive memory from stray magnetic fields.
Claim 2
Dependent Claim
50 words
A non-volatile magneto-resistive memory with stray magnetic shielding comprising: a non-volatile magneto-resistive memory positioned on a substrate and defining an upper surface; and a passivation layer at least partially surrounding the non-volatile magneto-resistive memory, the passivation layer including ferrite materials for shielding the non-volatile magneto-resistive memory from stray magnetic fields.
Claim 3
Dependent Claim
27 words
A non-volatile magneto-resistive memory with stray magnetic shielding as claimed in claim 1 wherein the ferrite materials include one of Mn--Zn-Ferrite, Ni--Zn-Ferrite, MnFeO, CuFeO, FeO, and NiFeO.
Claim 4
Dependent Claim
29 words
A non-volatile magneto-resistive memory with stray magnetic shielding as claimed in claim 1 wherein the ferrite materials are in the form of a powder intermixed with an encapsulation material.
Claim 5
Dependent Claim
34 words
A non-volatile magneto-resistive memory with stray magnetic shielding as claimed in claim 1 wherein the ferrite materials are in the form of a layer of the ferrite material positioned adjacent the non-volatile magneto-resistive memory.
Claim 6
Dependent Claim
113 words
A non-volatile magneto-resistive memory with stray magnetic shielding comprising: a non-volatile magneto-resistive memory positioned on a substrate and defining an upper surface, the non-volatile magneto-resistive memory including at least first and second layers of magneto-resistive material separated by a layer of non-magnetic material; a layer of high permeability, non-conductive magnetic material positioned adjacent the upper surface of the non-volatile magneto-resistive memory so as to focus internally generated magnetic fields on at least one of the first and second layers of magneto-resistive material and shield the non-volatile magneto-resistive memory from stray magnetic fields; and a passivation layer at least partially surrounding the layer of high permeability, non-conductive magnetic material and the non-volatile magneto-resistive memory.
Claim 7
Dependent Claim
113 words
A non-volatile magneto-resistive memory with stray magnetic shielding comprising: a non-volatile magneto-resistive memory positioned on a substrate and defining an upper surface, the non-volatile magneto-resistive memory including at least first and second layers of magneto-resistive material separated by a layer of non-magnetic material; a layer of high permeability, non-conductive magnetic material positioned adjacent the upper surface of the non-volatile magneto-resistive memory so as to focus internally generated magnetic fields on at least one of the first and second layers of magneto-resistive material and shield the non-volatile magneto-resistive memory from stray magnetic fields; and a passivation layer at least partially surrounding the layer of high permeability, non-conductive magnetic material and the non-volatile magneto-resistive memory.
Claim 8
Dependent Claim
25 words
A non-volatile magneto-resistive memory with stray magnetic shielding as claimed in claim 5 wherein the layer of high permeability, non-conductive magnetic material includes ferrite materials.
Claim 9
Dependent Claim
27 words
A non-volatile magneto-resistive memory with stray magnetic shielding as claimed in claim 6 wherein the ferrite materials include one of Mn--Zn-Ferrite, Ni--Zn-Ferrite, MnFeO, CuFeO, FeO, and NiFeO.
Claim 10
Dependent Claim
20 words
A non-volatile magneto-resistive memory with stray magnetic shielding as claimed in claim 5 wherein the passivation layer includes ferrite materials.
Claim 11
Dependent Claim
122 words
A non-volatile magneto-resistive memory with stray magnetic shielding comprising: a non-volatile magneto-resistive memory positioned on a semiconductor substrate, the non-volatile magneto-resistive memory including an array of individual cells with each cell including at least first and second layers of magneto-resistive material separated by a layer of non-magnetic material, the non-volatile magneto-resistive memory further including integrated circuitry addressing and controlling the individual cells with input/output terminals; and a layer of high permeability, non-conductive magnetic material coating at least an upper surface of the non-volatile magneto-resistive memory so as to focus internally generated magnetic fields on at least one of the first and second layers of magneto-resistive material in each of the individual cells and shield the non-volatile magneto-resistive memory from stray magnetic fields.
Claim 12
Dependent Claim
122 words
A non-volatile magneto-resistive memory with stray magnetic shielding comprising: a non-volatile magneto-resistive memory positioned on a semiconductor substrate, the non-volatile magneto-resistive memory including an array of individual cells with each cell including at least first and second layers of magneto-resistive material separated by a layer of non-magnetic material, the non-volatile magneto-resistive memory further including integrated circuitry addressing and controlling the individual cells with input/output terminals; and a layer of high permeability, non-conductive magnetic material coating at least an upper surface of the non-volatile magneto-resistive memory so as to focus internally generated magnetic fields on at least one of the first and second layers of magneto-resistive material in each of the individual cells and shield the non-volatile magneto-resistive memory from stray magnetic fields.
Claim 13
Dependent Claim
25 words
A non-volatile magneto-resistive memory with stray magnetic shielding as claimed in claim 9 wherein the layer of high permeability, non-conductive magnetic material includes ferrite materials.
Claim 14
Dependent Claim
27 words
A non-volatile magneto-resistive memory with stray magnetic shielding as claimed in claim 10 wherein the ferrite materials include one of Mn--Zn-Ferrite, Ni--Zn-Ferrite, MnFeO, CuFeO, FeO, and NiFeO.
Claim 15
Dependent Claim
36 words
A non-volatile magneto-resistive memory with stray magnetic shielding as claimed in claim 9 including in addition a passivation layer at least partially surrounding the layer of high permeability, non-conductive magnetic material and the non-volatile magneto-resistive memory.
Claim 16
Dependent Claim
20 words
A non-volatile magneto-resistive memory with stray magnetic shielding as claimed in claim 12 wherein the passivation layer includes ferrite materials.
Claim 17
Dependent Claim
27 words
A non-volatile magneto-resistive memory with stray magnetic shielding as claimed in claim 13 wherein the ferrite materials include one of Mn--Zn-Ferrite, Ni--Zn-Ferrite, MnFeO, CuFeO, FeO, and NiFeO.
Claim 18
Dependent Claim
31 words
A non-volatile magneto-resistive memory with stray magnetic shielding as claimed in claim 13 wherein the layer of high permeability, non-conductive magnetic material includes openings therethrough for access to the input/output terminals.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-05-10 | 2002-11-09 | 2003-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-10 | 2006-11-09 | 2007-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-10 | 2010-11-09 | 2011-05-11 | $7700.00 | Window Closed / Lapsed |