Impact of the barrier/dielectric interface quality on reliability of Cu porous-low-k interconnects

The purpose is to show that TDDB reliability of damascene structures has to be assessed as a system composed of a dielectric, copper diffusion barrier and copper. This becomes mandatory when porous low-k materials are considered, since barrier integrity is a key contributor in TDDB behavior. Solely addressing the dielectric properties is not adequate. When a not fully dense barrier is considered the apparent dielectric properties are degraded due to copper migration into the dielectric.