The Role of Particle Adhesion and Surface Deformation in Chemical Mechanical Polishing Processes

A conventional chemical mechanical polishing (CMP) removal rate model considered surface deformation by abrasive particles as an elastic Hertzian process. In this study, the contact pressure between a particle and surface is calculated and compared with the Young's modulus of the polished material. The particle penetration depth is also calculated and compared with surface roughness of post‐CMP wafers. It is found that plastic deformation is the most likely deformation mechanism of polished surfaces in CMP processes. For the first time, a new removal rate model based on the plastic deformation of the polished material and incorporating the important contribution of particle adhesion forces is established to monitor the polishing process and the model prediction is in good agreement with experimental removal rate data. The effects of the adhesion forces on the removal rate, surface roughness, and post‐CMP cleaning are also addressed. ©1998 The Electrochemical Society