Self contacting bit line to mram cell

Abstract

Embodiments of the invention disclose magnetic memory cell configurations in which a magnetic storage structure is coupled to an upper metal layer with minimal overlay margin. This greatly reduces a size of the memory cell.

1 . A magnetic memory cell, comprising:
 a memory element; and   an upper metal layer; wherein the memory element is directly coupled to the upper metal layer without the use of a via.   
     
     
         2 . The magnetic memory cell of  claim 1 , wherein the memory element comprises a Magnetic Tunnel Junction (MTJ) stack. 
     
     
         3 . The magnetic memory cell of  claim 2 , wherein a size of the MTJ stack is f and a width of the upper metal layer is f+2∂, where ∂ is an overlay margin for the upper metal layer. 
     
     
         4 . The magnetic memory cell of  claim 2 , further comprising dielectric sidewalls formed on opposed sides of the MTJ stack. 
     
     
         5 . The magnetic memory cell of  claim 1 , further comprising: a hard mask layer etched and patterned to sit atop the memory element. 
     
     
         6 . The magnetic memory cell of  claim 5 , wherein the memory element comprises a Magnetic Tunnel Junction (MTJ) stack. 
     
     
         7 . The magnetic memory cell of  claim 5 , wherein a size of the MTJ stack is f and a width of the upper metal layer is f+2∂, where ∂ is an overlay margin for the upper metal layer. 
     
     
         8 . The magnetic memory cell of  claim 5 , wherein the hard mask layer comprises a material selected from the group consisting of titanium nitride, titanium, aluminum, and tantalum. 
     
     
         9 - 11 . (canceled) 
     
     
         12 . A magnetic memory cell, comprising:
 a magnetic memory element;   a read lead directly coupled to a lower end of the magnetic memory element;   a bit line directly coupled to an upper end of the magnetic memory element; and   a word line positioned under the magnetic memory element such that the read lead passes between the word line and the magnetic memory element.   
     
     
         13 . The magnetic memory cell of  claim 12 , wherein a size of the magnetic storage element is f and a width of the bit line is f+2∂, where ∂ is an overlay margin for the bit line. 
     
     
         14 . The magnetic memory cell of  claim 12 , wherein the magnetic memory element comprises a Magnetic Tunnel Junction (MTJ) stack. 
     
     
         15 . The magnetic memory cell of  claim 13 , further comprising dielectric sidewalls formed on sides of the MTJ stack. 
     
     
         16 . The magnetic memory cell of  claim 12 , further comprising a hard mask layer etched and patterned to sit atop the memory element. 
     
     
         17 . A magnetic memory cell, comprising:
 a Magnetic Tunnel Junction (MTJ) stack including a plurality of layers;   a read lead directly coupled to a lower layer of the MTJ stack;   a bit line directly coupled to an upper layer of the MTJ stack; and   a word line positioned under the MTJ stack such that the read lead passes between the word line and the MTJ stack.   
     
     
         18 . The magnetic memory cell of  claim 17 , wherein a size of the MTJ stack is f and a width of the bit line is f+2∂, where ∂ is an overlay margin for the bit line. 
     
     
         19 . The magnetic memory cell of  claim 17 , wherein the plurality of layers of the MTJ stack comprises a pin layer, a tunnel oxide layer, and a fixed layer. 
     
     
         20 . The magnetic memory cell of  claim 17 , further comprising dielectric sidewalls formed on sides of the MTJ stack. 
     
     
         21 . The magnetic memory cell of  claim 17 , further comprising a hard mask layer etched and patterned to sit atop the MTJ stack. 
     
     
         22 . The magnetic memory cell of  claim 21 , wherein a size of the MTJ stack is f and a width of the upper metal layer is f+2∂, where ∂ is an overlay margin for the upper metal layer. 
     
     
         23 . The magnetic memory cell of  claim 21 , wherein the hard mask layer comprises a material selected from the group consisting of titanium nitride, titanium, aluminum, and tantalum.