Pre-liner dielectric nitridation for resistance reduction in copper interconnects

Adhesion tests, parametric measurements, and reliability evaluations of an in-situ pre-liner dielectric nitridation process prior to pure Ta liner deposition were carried out, to evaluate the feasibility of reducing via resistance in BEOL Cu/low-k interconnects. Replacing TaN/Ta with Ta in the conventional liner stack reduces Cu via resistance, while the nitridation treatment maintains Cu interconnect integrity and reliability.