International Business Machines Corporation
Back end of line structures with metal lines with alternating patterning and metallization schemes

Abstract:

Techniques are provided to fabricate semiconductor devices. For example, a method includes forming an interconnect structure having a base, a first conductive metal layer disposed on the base; and a first hardmask layer disposed on the first conductive metal layer. Metal lines are formed by subtractive etching. The metal lines have negative tapered sidewalls, and an opening is formed between adjacent metal lines. A first interlevel dielectric layer is deposited in the openings. A portion of the first interlevel dielectric layer is removed to form trench openings having positive tapered sidewalls. A dielectric layer is deposited in one of the openings. A liner layer and a second conductive metal layer are deposited in the other trench openings. The liner layer and the second conductive metal layer are recessed. A second hardmask layer is deposited on a top surface of the liner layer and the second conductive metal layer.