Methods and masks for line end formation for back end of line (BEOL) interconnects and structures resulting therefrom

A method of fabricating an interconnect structure for a semiconductor die, the method comprising:

• forming a hardmask layer above a sacrificial material layer;
• forming a first patterned hardmask layer above the hardmask layer, the first patterned hardmask layer having a grating pattern with a first direction;
• forming a second patterned hardmask layer above the first patterned hardmask layer, the second patterned hardmask layer having a grating pattern with a second direction orthogonal to the first direction;
• forming a lithographic patterning mask above the second patterned hardmask layer, the lithographic patterning mask having openings exposing selected line end locations for the sacrificial material layer;
• removing portions of the first patterned hardmask layer not protected by the openings of the lithographic patterning mask to form a third patterned hardmask layer, wherein exposed regions of the second patterned hardmask layer also exposed by the openings confine the removal of the portions of the first patterned hardmask layer;
• removing the lithographic patterning mask and the second patterned hardmask layer;
• and
• transferring a pattern of the third patterned hardmask layer to the hardmask layer and to the sacrificial material layer.