Effects of Particle Concentration on Chemical Mechanical Planarization

Effects of particle concentration on removal rates in chemical mechanical planarization (CMP) were investigated. Experimental data shows the removal rate scales with the cubic root of weight percent solids and is proportional to mean separation distance between particles in the slurry. Results show similar removal rate scaling with solid concentration for both silicon dioxide and copper films. This work also identifies a critical solid concentration needed to initiate removal for oxide or copper surfaces. The effects of particles on copper surface oxidation and roughness are further characterized by voltammetry and atomic force microscopy. Results show copper films become progressively smoother with additional solids in the slurry.