CHEMICAL-MECHANICAL POLISHING OF COPPER FOR MULTILEVEL METALLIZATION

A systematic study of Cu CMP in terms of process parameters has been p erformed, Correlations were found between the processing conditions an d the across-wafer nonuniformity which is a critical aspect of the pla narization process, Higher polish pressure and lower velocity during C MP tend to increase the center-to-edge variation of the removal rate, Polishing blanket Cu films, an across-wafer nonuniformity less than 5% has been achieved. We successfully demonstrate a process to polish Cu /W-Ti on patterned SiO2 films and stop at the dielectric in order to f orm Cu lines, We have examined the effects of Cu dishing and SiO2 thin ning which lead to deviation of the Cu line thickness. Both were found to be sensitive to the pattern geometry and the overpolishing time. C u dishing is affected by the line width and line space, SiO2 thinning depends only on the line space.