Physical, Electrical, and Reliability Characterization of Ru for Cu Interconnects

Thin film characterization, electrical performance, and preliminary reliability of physical vapor-deposited (PVD) TaN/chemical vapor-deposited (CVD) Ru bilayer were carried out to evaluate its feasibility as a liner layer for back-end of line (BEOL) Cu-low k integration. Adhesion and barrier strength were studied using 4-point bend, X-ray diffraction (XRD), and triangular voltage sweep (TVS) techniques. Electrical yields and line/via resistances were measured at both single and dual damascene levels, with PVD TaN/Ta liner layer as a baseline control. Reliability studies included electromigration (EM) and current-voltage (I-V) breakdown tests