Copper and low-k dielectrics as interconnect materials for advanced microelectronic devices have reliability concerns due to their electrical and mechanical vulnerability. The leakage current of low-k dielectric was studied widely to understand the reliability property. Previous studies focused on intra level voltage bias and emphasized the effect and leakage conduction mechanism in the cap layer, but the role of low k dielectric was not clear . Other low-k leakage study showed different conduction mechanism but not under practical interconnect environment . The characteristic of carrier injection between metal and dielectric was not well addressed previously. Therefore, we study the leakage currents of intra and inter level low-k dielectric with different electron injection directions in practical IC environment, in order to have thorough understanding of the conduction effect on low-k dielectric reliability.