TDDB and voltage-ramp reliability of SiC-base dielectric diffusion barriers in Cu/low-k interconnects

Failure modes for inter-level dielectric layers under accelerated test conditions are evaluated for copper/low-k interconnects. The dominant failure mode under high voltage stress conditions appears to be mechanical cracking at the dielectric barrier/low-k interface. A simple model for the electrostatic force between interdigitated lines is able to account for the failure with certain assumptions about interfacial adhesion strength of the dielectric diffusion barrier.