Amorphous thin film TaWSiC as a diffusion barrier for copper interconnects

摘要

A very thin and amorphous TaWSiC film with relatively low resistivity of 233μΩ-cm was studied for its effectiveness as a diffusion barrier for copper interconnects. A 5 nm thick TaWSiC barrier effectively prevents copper diffusion and maintains structural integrity up to an annealing temperature of at least 550 ℃, with copper silicide formation observed at 650 ℃. In comparison, a barrier of 5 nm of nanocrystalline Ta already fails at 550 ℃. Being very thin and amorphous, while having low resistivity and good thermal stability, are crucial properties of a good diffusion barrier for future technology, and this film meets these requirements.