Back end of line structures with metal lines with alternating patterning and metallization schemes

A method comprising:

• forming an interconnect structure comprising a base, a first conductive metal layer disposed on the base, and a first hardmask layer disposed on the first conductive metal layer;
• forming metal lines by patterning the first hardmask layer and the first conductive metal layer above the base by subtractive etching, wherein the metal lines have negative tapered sidewalls, and further wherein an opening is formed between adjacent metal lines;
• depositing a first interlevel dielectric layer in the opening between the adjacent metal lines;
• removing a portion of the first interlevel dielectric layer to form trench openings having positive tapered sidewalls;
• depositing a dielectric layer in a trench opening;
• depositing a liner layer on the exterior surfaces of the other trench openings;
• depositing a second conductive metal layer on the liner layer;
• recessing the liner layer and the second conductive metal layer;
• and
• depositing a second hardmask layer on a top surface of the liner layer and the second conductive metal layer.