A method of fabricating a miniaturized semiconductor device so as to form MTJ elements therein include the steps of depositing a magnetic tunnel junction (MTJ) precursor layer on a substrate and planarizing the precursor layer; forming a sacrificial and patternable dielectric layer on the MTJ precursor layer; patterning the sacrificial dielectric layer in accordance with predetermined placements and shapes of a to-be-formed hard mask, the patterning forming corresponding openings in the sacrificial dielectric layer; depositing an etch-resistant conductive material such as Cu in the openings for example by way of plating, and selectively removing the sacrificial dielectric layer so as to leave behind the etch-resistant conductive material in the form of a desired hard mask. Using the hard mask to etch and thus pattern the MTJ precursor layer so as to form MTJ elements having desired locations, sizes and shapes.