TDDB reliability assessments of 0.13 μm Cu/low-k interconnects fabricated with PECVD low-k materials

Time-dependent dielectric breakdown (TDDB) measurements were used to predict lifetime of Cu/low-k interconnects. A voltage ramp test (Vramp) was performed in the beginning, to determine appropriate TDDB stress conditions. The low-field "E-Model" was then used to extrapolate to MTTF at 3.3V and 100°C. The calculated E-Model parameters are comparable to other published results. It was observed that thermally induced diffusion dominates the lifetime extrapolation by at least two orders of magnitude. By delaying the Cu diffusion process by relevant interface engineering, reliability of Cu/low-k interconnects can be improved.