Interfacial Characterization of Electrodeposited Cu on 5-10 nm Ru Films Supported by Low-k Dielectrics

Recent success of the advanced physical vapor deposition development allows highly engineered Ta/TaN barrier to be extended through 90 nm node. The tri-layer Cu-seed/Ta/TaN will likely encounter scaling difficulties in the damascene trench/via features of advanced 65 and 45 nm nodes. To enhance the overall integration success, it is highly desirable to search for a Cu-plate-able single-layer barrier/liner for future Cu interconnects application. As an alternative barrier metal, ultra thin ruthenium films are investigated not only as a replacement adhesive diffusion barrier layer, but also as a suitable conductive substrate for electrochemical deposition of copper in an ILD / Ru/ECD copper stacks1-4. IC chips fabricated with more conductive Cu interconnects and low-k dielectrics operate with les