Resistivity of copper interconnects at 28 nm pitch and copper cross-sectional area below 100 nm²

The resistivity of damascene Cu is measured at cross-sectional area as low as 95 nm2. The impact of aspect ratio and line edge roughness on resistivity is investigated. Kelvin resistance test structures are demonstrated with 28 nm pitch wires patterned by directed self-assembly of lamellar block copolymers. The effective resistivity of TaN/Ta/Cu wires is compared with alternative metals.