Evaluation of inter and intra level TDDB of Cu/Low-k interconnect for high voltage application

Conduction currents and TDDB results of intra and inter level low-k dielectric structures are studied and compared for high voltage application. Electrical field distributions are different for the different structures and impact the TDDB results. Failure analysis shows that Cu ion diffusion and cap interfaces are dominant impact factors for the low-k dielectric breakdown. A layout design principle of inter level low-k structure optimization to improve dielectric reliability under high voltage operation is suggested.