Patent ID: 6979526

Claim:
A method of manufacturing a magnetoresistive semiconductor device, comprising: providing a semiconductor workpiece; forming an insulating layer over the workpiece; defining a pattern of trenches as a plurality of alignment mark trenches and a plurality of trenches for conductive lines within the insulating layer; forming a liner over said plurality of alignment mark trenches and said plurality of trenches for conductive lines; forming a resist over the alignment mark trenches; depositing a conductive material over the insulating layer not covered by the resist to fill the conductive line trenches and form conductive lines, leaving excess conductive material disposed over the conductive lines; removing the resist from over the alignment mark trenches and removing the excess conductive material from over the conductive lines, wherein the alignment mark trenches in the insulating layer are not covered by said conductive material; and then depositing a magnetic stack layer over all exposed surfaces including the conductive lines, the insulating layer top surface and the alignment mark trenches; patterning the magnetic stack layer to form a magnetic tunnel junction (MTJ) over each conductive line; and removing said liner and said resist in said alignment mark trenches to expose the insulating layer at the bottom and sidewalls of said alignment mark trenches, so that said alignment mark trenches are suitable for alignment of subsequent layers of the magnetoresistive semiconductor device.