A new removal rate model which is a modification to the Preston equation is developed to re-account the dependence of removal rate on the down force (pressure) and rotation speed during the chemical-mechanical polishing (CMP) process. The removal rate is first expressed as a linear function of both normal and shear stresses. The analogy of the CMP removal process to traveling indenters is considered and the stresses acting upon the abrasive particles (indenters) are formulated using previous models based on principles of elasticity and fluid mechanics. An expression is then derived which predicts the (pressure)5'6 and (speed)112 dependences of the removal rate. Experimental results with thermal oxides are consistent with the predictions. Chemical-mechanical polishing (CMP) has been widely recognized as the most promising method that achieves both local and global planarization for ultralarge scale integrated circuit (ULSI) manufacturing processes.t'2 The polishing (material removal) mechanism is still obscure however and the process control and basic understanding of this technology remain essentialy on the empirical level. So far most CMP users and researchers adopt Preston's equation3 to monitor removal rate. This equation incorporates the pressure (I and speed ( as the main contributors to removal rate (R.R.)