US2004126905A1PendingUtilityA1

Magnetic shielding for MRAM devices

39
Individually held — no corporate assignee on recordPriority: Apr 18, 2002Filed: Dec 15, 2003Published: Jul 1, 2004
Est. expiryApr 18, 2022(expired)· nominal 20-yr term from priority
Inventors:Manoj BhattacharyyaDarrel BloomquistJudy BloomquistAnthony HoldenSarah Brandenberger
Y10T428/26H10B 61/00
39
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Claims

Abstract

A magnetic random access memory module includes a magnetic memory array. A permeable metal layer extends over a first side of the magnetic memory array. An electrically insulating layer is disposed between the permeable metal layer and the magnetic memory array.

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
         1 . A magnetic random access memory module comprising: 
 a magnetic memory array;    a permeable metal layer extending over a first side of the magnetic memory array; and    an electrically insulating layer disposed between the magnetic memory array and the permeable metal layer.    
     
     
         2 . The memory module of  claim 1 , wherein the permeable metal layer comprises a soft magnetic material.  
     
     
         3 . The memory module of  claim 2 , wherein soft magnetic material is selected from the group consisting of iron, nickel, cobalt, alloys of iron, alloys of nickel and alloys of cobalt.  
     
     
         4 . The memory module of  claim 1 , wherein the permeable metal layer has a permeability of greater than 10.  
     
     
         5 . The memory module of  claim 1 , wherein the permeable metal layer has an anisotropy of less than 100 Oe.  
     
     
         6 . The memory module of  claim 1 , wherein the permeable metal layer is isotropic.  
     
     
         7 . The memory module of  claim 1 , wherein the magnetic memory array comprises: 
 a plurality of magnetic memory cells; and    a pair of write conductors operatively positioned adjacent each of the plurality of magnetic memory cells.    
     
     
         8 . The memory module of  claim 7 , wherein each of the plurality of magnetic memory cells comprises: 
 a reference layer having a pinned magnetization;    a sense layer having an alterable magnetization; and    a dielectric layer separating the reference layer and the sense layer.    
     
     
         9 . The memory module of  claim 1 , wherein the permeable metal layer has an area larger than an area of the magnetic memory array.  
     
     
         10 . The memory module of  claim 9 , wherein the area of the permeable metal layer is at least twice the area of the magnetic memory array.  
     
     
         11 . The memory module of  claim 7 , wherein the spacing between the permeable metal layer and the plurality of memory cells is 10 microns or less.  
     
     
         12 . The memory module of  claim 1 , wherein the permeable metal layer has an annealing temperature lower than an annealing temperature of the magnetic memory array.  
     
     
         13 . A method for shielding a magnetic random access memory module from stray magnetic fields, comprising: 
 attaching a layer of electrically insulating material adjacent a magnetic memory array in the memory module; and    attaching a layer of permeable metal over the insulating material.    
     
     
         14 . The method of  claim 13 , wherein attaching a layer of permeable metal over the insulating material comprises sputtering the permeable metal in a rotating magnetic field.  
     
     
         15 . The method of  claim 13 , wherein attaching a layer of permeable metal over the insulating material comprises: 
 sputtering the permeable metal; and    annealing the sputtered permeable metal in a rotating magnetic field.    
     
     
         16 . The method of  claim 15 , wherein annealing the sputtered permeable metal in a rotating magnetic field comprises annealing the sputtered permeable metal while rotating the memory module in an annealing station in the presence of a stationary magnetic field.  
     
     
         17 . The method of  claim 15 , wherein annealing the sputtered permeable metal in a rotating magnetic field comprises annealing the sputtered permeable metal while rotating a permanent magnet in an annealing station.  
     
     
         18 . The method of  claim 15 , wherein annealing the sputtered permeable metal includes annealing the permeable metal at a temperature that is lower than an annealing temperature of a magnetic material in the memory module.  
     
     
         19 . The method of  claim 13 , wherein attaching a layer of isotropic permeable metal comprises adhesively securing a sheet of high permeability metal to the insulating layer.  
     
     
         20 . The method of  claim 19 , wherein the insulating layer is an adhesive.  
     
     
         21 . A magnetic random access memory module comprising: 
 a plurality of magnetic memory cells;    a plurality of write conductors, each of the write conductors positioned adjacent an associated one of the plurality of magnetic memory cells;    an isotropic magnetically permeable metal layer extending continuously over at least one side of the magnetic memory cells and associated write conductors; and    an electrically insulating layer disposed between the permeable metal layer and the write conductors.    
     
     
         22 . A method for shielding a magnetic random access memory module from stray magnetic fields, the method comprising: 
 depositing a layer of electrically insulating material over a surface of a magnetic memory array;    sputtering a layer of permeable metal layer over the layer of electrically insulating material such that the permeable metal layer extends continuously over the magnetic memory array;    annealing the sputtered layer of permeable metal to make the layer of permeable metal isotropic.

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