Tantalum-containing barrier layers for copper

摘要

An improved barrier layer of tantalum to prevent diffusion of copper into a dielectric layer or silicon substrate is made by alternately sputter depositing thin amorphous tantalum layers and tantalum nitride layers. The resultant wholly amorphous tantalum-containing layer leads to a stronger barrier and prevents formation of a columnar structure in thick tantalum layers. The sputter depositions of tantalum and tantalum nitride can be repeated until the desired thickness of the barrier is obtained.