Breakthrough in 19 nm half-pitch W damascene interconnects using nanoimprint lithography and atomic-scale processing

Abstract To evaluate the lithographic capability in nanoimprint lithography (NIL) through electrical (E)-test, we fabricate tungsten (W) damascene interconnects with a minimum half-pitch (HP) of 19 nm, using atomic-scale transfer etching, atomic layer deposition (ALD) of TiN/W, and chemical mechanical polishing (CMP). In-situ carbon deposition in the transfer etching is the key to adjusting the critical dimension at the atomic-scale, thereby suppressing the collapse of the hard mask pattern of the spin-on-carbon layer during the etching. Seamless metal embedding was achieved by combining ALD and CMP in the trenches of the 19 nm HP interconnect test element group (TEG) patterned by NIL. The E-test results obtained from a single-wafer test indicate that the open/short TEG exhibits narrow distributions in the W line resistances and the interline leakage currents for the 19 nm HP across 76 chips on the 300 mm wafer.