Development of plasma-enhanced atomic layer deposition grown Ru-WCN mixed phase films for nanoscale diffusion barrier and copper direct-plate applications

A novel mixed phase Ru-WCN film grown by plasma-enhanced atomic layer deposition has been investigated as a novel direct-plate liner for advanced copper metallization. Ru-WCN films were grown using a nanolaminate approach, and the. properties of the films were investigated as they relate to specific changes to processing conditions. The microstructure was found to consist of polycrystalline Ru grains within an amorphous WCN matrix. Preliminary results show that both mixed phase liner composition and thickness contribute to the ability of the film to facilitate dense copper electrolytic plating. Electrical diffusion barrier testing indicates that similar to 2-3 nm thick liners with metal ratios as high as 11:1 Ru:W can be employed as a directly platable Cu diffusion barrier solution. (C) 2009 American Vacuum Society. [DOI: 10.1116/1.3097856]