Effects of kinematic variables on nonuniformity in chemical mechanical planarization

The effects of kinematic variables on the nonuniformity of the wafer in chemical mechanical planarization (CMP) are investigated. The nonuniform amount of material removal is calculated by the velocity integral and the experimental nonuniformity is measured. This analysis becomes more important as the wafer size increases and the requirement for within-wafer nonuniformity is more rigorous. The effects of the rotational and translational speeds and carrier eccentricity are discussed. The significance of velocity uniformity is proved based on the analysis and experiment. The wafer size possesses great importance in the nonuniformity. Large eccentricity is useful, while the translation speed of the carrier plays a minor role in view of kinematics. The analysis provides a guide to the design of a process window in CMP. The experimental results support the analytical approach.