Integration of CVD W- and Ta-based Liners for Copper Metallization

Both TaNx and WNx are candidates for copper liner applications. A thermal CVD process for the deposition of WNx liners, as well as both thermal CVD and plasma-assisted CVD processes for the deposition of TaNx, have been developed, all of which are carried out at wafer temperatures under 425°C. The basic material properties, conformality, thermal stability, and integration and diffusion barrier properties of these materials make them appropriate for use in advanced copper-based interconnect applications.