US6153443A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of fabricating a magnetic random access memory
Assignee: Everspin Technologies Inc
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Filing: 1998-12-21
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Granted: 2000-11-28
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Expires: 2018-12-21
Abstract
Abstract An improved and novel fabrication method for magnetoresistive random access memory (MRAM) is provided. An MRAM device has memory elements and circuitry for managing the memory elements. The circuitry includes transistor (12a), digit line (29), etc., which are integrated on a substrate (11). The circuitry is fabricated first under the CMOS process and then magnetic memory elements (53, 54). A dielectric layer (40, 41) is deposited on the circuit, and trenches (42, 43) are formed in the dielectric layer. A blanket layer (46), which includes magnetic layers (48, 49) and a non-magnetic layer (50) sandwiched by the magnetic layers, is deposited on dielectric layer (41) and in the trenches. Then, the blanket layer outside the trenches is removed and MRAM elements (53, 54) are formed in the trenches.
Inventors
- 👤 Mark Durlam
- 👤 Gloria Kerszykowski
- 👤 Jon M. Slaughter
- 👤 Eugene Chen
- 👤 Saied N. Tehrani
- 👤 Kelly W. Kyler
- 👤 X. Theodore Zhu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:56
CPC Classifications
B; B82; B82Y; B82Y10/00; G; G11; G11C; G11C11/00; G11C11/02; G11C11/14; G11C11/15; H; H10; H10B; H10B61/00; H10B61/20; H10B61/22; H10B69/00
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
81 words
A method of fabricating a random access memory having a magnetic memory cell and circuitry for controlling operations of the magnetic memory cell, the method comprising the steps of: providing a substrate on which the magnetic memory cell and the circuitry are formed; forming the circuitry on the substrate; depositing a dielectric layer on the circuitry; forming a trench in the dielectric layer; and forming the magnetic memory cell in the trench, the magnetic memory cell being coupled to the circuitry.
Claim 2
Independent Claim
81 words
A method of fabricating a random access memory having a magnetic memory cell and circuitry for controlling operations of the magnetic memory cell, the method comprising the steps of: providing a substrate on which the magnetic memory cell and the circuitry are formed; forming the circuitry on the substrate; depositing a dielectric layer on the circuitry; forming a trench in the dielectric layer; and forming the magnetic memory cell in the trench, the magnetic memory cell being coupled to the circuitry.
Claim 3
Dependent Claim
47 words
The method of fabricating the random access memory as claimed in claim 1 wherein the step of depositing the dielectric layer includes a step of depositing a first dielectric layer on the circuitry and a step of depositing a second dielectric layer on the first dielectric layer.
Claim 4
Dependent Claim
62 words
The method of fabricating the random access memory as claimed in claim 1 wherein the step of forming the magnetic memory cell includes steps of: depositing a blanket layer over the dielectric layer and in the trench; depositing an electrically conductive layer overlying the blanket layer; and removing the electrically conductive layer and the blanket layer which are outside of the trench.
Claim 5
Dependent Claim
48 words
The method of fabricating the random access memory as claimed in claim 3 wherein the step of depositing the blanket layer includes steps of: depositing a first magnetic layer; depositing a non-magnetic layer on the first magnetic layer; and depositing a second magnetic layer on the non-magnetic layer.
Claim 6
Dependent Claim
46 words
The method of fabricating the random access memory as claimed in claim 3 wherein the step of removing the electrically conductive layer and the blanket layer includes a step of polishing the electrically conductive layer and the blanket layer by a chemical mechanical polishing (CMP) technique.
Claim 7
Dependent Claim
35 words
The method of fabricating the random access memory as claimed in claim 1 wherein the step of forming the circuitry includes a step of forming a first electrically conductive line adjacent the magnetic memory cell.
Claim 8
Dependent Claim
46 words
The method of fabricating the random access memory as claimed in claim 6 wherein the step of forming the first electrically conductive line includes a step of forming a flux concentrating layer around the first electrically conductive line except a surface toward the magnetic memory cell.
Claim 9
Dependent Claim
42 words
The method of fabricating the random access memory as claimed in claim 6 further including a step of forming a second electrically conductive line that is perpendicular to the first electrically conductive line and is electrically coupled to the magnetic memory cell.
Claim 10
Dependent Claim
46 words
The method of fabricating the random access memory as claimed in claim 8 wherein the step of forming the second electrically conductive line includes a step of forming a flux concentrating layer around the second electrically conductive line except a surface toward the magnetic memory cell.
Claim 11
Dependent Claim
49 words
The method of fabricating the random access memory as claimed in claim 1 wherein the step of forming the magnetic memory cell includes steps of: depositing a first magnetic layer; depositing a non-magnetic layer on the first magnetic layer; and depositing a second magnetic layer on the non-magnetic layer.
Claim 12
Dependent Claim
39 words
The method of fabricating the random access memory as claimed in claim 10 wherein the step of depositing a non-magnetic layer includes a step of forming a tunneling junction between the first magnetic layer and the second magnetic layer.
Claim 13
Dependent Claim
40 words
The method of fabricating the random access memory as claimed in claim 1 wherein the step of forming the circuitry on the substrate includes a step of fabricating the circuitry under a process for a complimentary metal oxide semiconductor (CMOS).
Claim 14
Dependent Claim
58 words
The method of fabricating the random access memory as claimed in claim 1 wherein the step of forming the magnetic memory cell includes steps of: depositing a blanket layer over the dielectric layer and in the trench; depositing a dielectric layer overlying the blanket layer and in the trench; and removing the dielectric layer on the blanket layer.
Claim 15
Dependent Claim
48 words
The method of fabricating the random access memory as claimed in claim 13 wherein the step of depositing the blanket layer includes steps of: depositing a first magnetic layer; depositing a non-magnetic layer on the first magnetic layer; and depositing a second magnetic layer on the non-magnetic layer.
Claim 16
Dependent Claim
36 words
The method of fabricating the random access memory as claimed in claim 13 wherein the step of removing the dielectric layer includes a step of polishing the dielectric layer by a chemical mechanical polishing (CMP) technique.
Claim 17
Independent Claim
153 words
A method of fabricating a random access memory having a magnetic memory cell and circuitry for controlling operations of the magnetic memory cell, the method comprising the steps of: providing a substrate on which the magnetic memory cell and the circuitry are formed; forming the circuitry on the substrate including a first electrically conductive line; depositing a dielectric layer on the circuitry; isotropicly etching the dielectric layer to form an undercut trench on the first electrically conductive line; depositing a blanket layer over the dielectric layer and in the undercut trench; depositing an electrically conductive layer overlying the blanket layers; removing the electrically conductive layer outside of the undercut trench and the blanket layers on the dielectric layer; and forming a second electrically conductive line that is perpendicular to the first electrically conductive line and is electrically coupled to the magnetic memory cell through the electrically conductive layer on the magnetic memory cell.
Claim 18
Independent Claim
153 words
A method of fabricating a random access memory having a magnetic memory cell and circuitry for controlling operations of the magnetic memory cell, the method comprising the steps of: providing a substrate on which the magnetic memory cell and the circuitry are formed; forming the circuitry on the substrate including a first electrically conductive line; depositing a dielectric layer on the circuitry; isotropicly etching the dielectric layer to form an undercut trench on the first electrically conductive line; depositing a blanket layer over the dielectric layer and in the undercut trench; depositing an electrically conductive layer overlying the blanket layers; removing the electrically conductive layer outside of the undercut trench and the blanket layers on the dielectric layer; and forming a second electrically conductive line that is perpendicular to the first electrically conductive line and is electrically coupled to the magnetic memory cell through the electrically conductive layer on the magnetic memory cell.
Claim 19
Dependent Claim
43 words
The method of fabricating the random access memory as claimed in claim 16 wherein the step of forming the circuitry includes a step of forming a flux concentrating layer around the first electrically conductive line except a surface toward the magnetic memory cell.
Claim 20
Dependent Claim
47 words
The method of fabricating the random access memory as claimed in claim 16 wherein the step of depositing a dielectric layer includes a step of depositing a first dielectric layer on the circuitry and a step of depositing a second dielectric layer on the first dielectric layer.
Claim 21
Dependent Claim
46 words
The method of fabricating the random access memory as claimed in claim 16 wherein the step of forming the second electrically conductive line includes a step of forming a flux concentrating layer around the second electrically conductive line except a surface toward the magnetic memory cell.
Claim 22
Dependent Claim
48 words
The method of fabricating the random access memory as claimed in claim 16 wherein the step of depositing the blanket layer includes steps of: depositing a first magnetic layer; depositing a non-magnetic layer on the first magnetic layer; and depositing a second magnetic layer on the non-magnetic layer.
Claim 23
Dependent Claim
39 words
The method of fabricating the random access memory as claimed in claim 20 wherein the step of depositing a non-magnetic layer includes a step of forming a tunneling junction between the first magnetic layer and the second magnetic layer.
Claim 24
Dependent Claim
40 words
The method of fabricating the random access memory as claimed in claim 20 wherein the step of forming the circuitry on the substrate includes a step of fabricating the circuitry under a process for a complimentary metal oxide semiconductor (CMOS).
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-11-28 | 2004-05-29 | 2004-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-11-28 | 2008-05-29 | 2008-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-11-28 | 2012-05-29 | 2012-11-28 | $7700.00 | Window Closed / Lapsed |