A Material Removal Modeling of Chemical Mechanical Polishing Based on Micro-Contact Mechanism
The model proposed integrates process parameters including pressure and velocity and other important input parameters including the wafer hardness, pad roughness, abrasive size, and abrasive geometry into the formulation to predict the material removal rate. Based on the deformation of hyper-elastic asperities attached to a linear-elastic pad, contact mechanism between the asperities and the wafer is analyzed. Micro-contact mechanism between the particle and wafer is proposed on the basis of elastic-plastic deformation theory. Material removal rate of single abrasive particle is calculated by the abrasive wear theory. The fluid effect in the current model is attributed to the number of active abrasives. Wafer scale material removal rate is analyzed in detail, which is agreed with the experimental results. The Preston’s coefficient, which has been determined empirically, is now given as a function of various processing variables, pad roughness, wafer material properties and slurry status.
S. W. Du et al., "A Material Removal Modeling of Chemical Mechanical Polishing Based on Micro-Contact Mechanism", Key Engineering Materials, Vols. 474-476, pp. 472-477, 2011