Chemical mechanical planarization (CMP) has been widely recognized as the most promising technology to eliminate topographic variation and achieve wafer-level (global) planarization for ultralarge-scale integrated (ULSI) circuits. 2-3 Despite its extensive utilization, however, the process control of CMP remains at an empirical stage and most users still refer to the Preston equation 4 as the wafer-scale material removal model. This equation states that the removal rate, RR, is proportional to the product of the polish pressure, P, and velocity, V, i.e. RR ϭ k p PV [1] where k p is the Preston coefficient. Originally proposed for glass polishing, the Preston equation is also of an empirical nature and lacks scientific basis. Uncertainty remains regarding the basic polish behavior. Recent theoretical work and experimental evidence suggest that the Preston equation may overestimate the CMP removal rate. 1,5 Tseng and Wang 1 proposed an analytical model that predicts a P 5/6 V 1/2 , instead of Preston's PV dependence of CMP removal rate RR ϭ MP 5/6 V 1/2 [2]