Lithography method to reduce spacing between interconnect wires in interconnect structure

Abstract

In some embodiments, the present disclosure relates to a method that includes depositing multiple hard mask layers over an interconnect dielectric layer. A first patterning layer is deposited over the multiple hard mask layers, and a first masking structure is formed over the first masking structure. The first masking structure has openings formed by a first extreme ultraviolet (EUV) lithography process. Portions of the first patterning layer are removed according to the first masking structure. A second masking structure is formed within the patterned first patterning layer. A third masking structure is formed over a topmost one of the hard mask layers and has openings formed by a second EUV lithography process. Removal processes are performed to pattern the multiple hard mask layers to form openings in the interconnect dielectric layer, and interconnect wires having rounded corners are formed within the openings of the interconnect dielectric layer.