Material removal mechanism under non-contact condition between the pad and the wafer in the chemical mechanical polishing (CMP) process is investigated. Based on the assumption that almost all effective material removals take place due to the active abrasives which cut material through the plowing effects. A novel model is developed to predict the material removal rate (MRR) under non-contact condition between the pad and the wafer in CMP. Validated by the experimental data, the model is proved to be able to predict the change of MRR under non-contact condition. Numerical simulation of the model shows: the relative velocity u between the pad and the wafer and fluid viscosity η are the most important factors which impact MRR under non-contact condition; load changes of wafer also affects the MRR, but the effect is not as obvious as the relative velocity and fluid viscosity; when the radius of abrasive is not less than 50nm, the impact of MRR alone with the changes in the size of the abrasive can be ignored.
