Slurries for Copper Damascene Patterning:Similarities and Differences

摘要

Two first-step copper damascene slurries and one commercial second-step slurry are characterized in terms of their intrinsic properties and CMP performance.A prototype first-step slurry with high static etch rate (approx 150 nm/min) yielded higher dishing in the copper lines (approx 200 nm in 100 mum lines) compared to a commercial first-step slurry with negligible static etch rate.In both the cases,dishing in copper lines is observed to be a strong function of line width and radial position on the wafer.High static etch rate of the prototype slurry is believed to be responsible for the high dishing.Non-selective second-step polishing removes the linear layer while maintaining planarity.