Patent ID: 7067330

Claim:
A method of forming an MTJ MRAM cell between the intersection of ultra-thin word and bit lines comprising: providing a substrate having a substantially planar upper surface; forming on said substrate an ultra-thin horizontal bit line of high conductivity material, extending in a first direction and having a width between approximately 300 nm and 500 nm and a thickness that is less than 100 nm, wherein said formation further comprises: forming a first layer of high conductivity material on said substrate, said layer having a thickness that is less than 100 nm; forming a layer of photoresist on said first conducting layer; patterning said photoresist layer to leave a strip of width between approximately 300 nm and 500 nm; using said strip as an etch mask to remove portions of said first high conductivity material layer peripheral to said strip; depositing a layer of insulating material to refill said removed first conducting layer portions; removing a photoresist strip, leaving thereby a bit line and surrounding insulating layer having a common and substantially planar upper surface; forming a multilayered magnetic tunnel junction (MTJ) element on the substantially planar upper surface of said bit line, a lower surface of said MTJ element electrically contacting said bit line; forming a layer of insulation surrounding said MTJ element, an upper surface of said layer being co-planar with an upper surface of said MTJ element and with a planar substrate surface.