Patent ID: 7445943

Claim:
A method for forming an array of magnetoresistive random access memory (MRAM) bits employing magnetic tunnel junctions (MTJ), wherein at least some individual MRAM bits are formed by the method, comprising: providing a substrate comprising first conductive write line insulated from the substrate and having an upper surface; forming a first etch-stop layer above the upper surface; forming above the first etch-stop layer a magnetic tunnel junction (MTJ) comprising upper and lower electrodes wherein the lower electrode is separated from the first write line by at least the first etch-stop layer; etching at least the lower electrode with a reagent to which the etch-stop layer is substantially impervious; forming an upper interconnect coupled to the upper electrode of the MTJ; forming a dielectric layer above the upper interconnect; and forming a second conductive write line overlying the dielectric layer.