Intrinsic Reliability of BEOL interlayer dielectric

As interconnect dimensions shrink, interlayer breakdown is increasingly relevant to reliability. This paper presents TDDB, voltage acceleration, and leakage data for Cu and Co interconnects. The leakage mechanism is found to be Poole-Frenkel saturation transitioning to Fowler-Nordheim tunneling at high field. We conclude the interlayer lifetime is limited by the low-k dielectric and propose an E-model acceleration. The reliability of interlayer TDDB must consider the asymmetric voltage division of the etch stop/low-k stack.