Test Structure Design for Precise Understanding of Cu/Low-k Dielectric Reliability

Single line test structures are suggested for failure analysis and reliability improvement development, apart from using the conventional comb test structures. This is due to the challenges in controlling the damage after electrical tests as well as in pin-pointing sub-surface failures with present techniques. Three failure modes were observed in the new test structure, which can be identified by its I-V leakage characteristics. These also demonstrate the importance of including different geometrical layouts for backend reliability characterization