Assessment of copper contamination impact on inter-level dielectric reliability performed with time-dependent-dielectric-breakdown tests

Time-Dependent-Dieiectric-Breakdown (TDDB) tests have been conducted on dif ferently copper-contaminated Metal-Oxide-Silicon (MOS) capacitors in which the insulator was the same as the interconnects Inter-Level Dielectric (ILD ). TDDB tests are particularly sensitive in addressing the properties of Cu -contaminated dielectric and they are suitable for the characterization of diffusion barrier layers for Cu based interconnects. The lifetime dependenc e of (LH) on Cu contamination clearly shows that the lost of insulating per formances can be a new degrading mechanism related to Cu-based interconnect s. It is also shown that technological process steps could impact the relia bility of Cu interconnects: without effective cleaning steps any effort mad e in providing strong diffusion barrier could vanish. (C) 2000 Elsevier Sci ence Ltd. All rights reserved.