A locally relevant wafer-scale model for CMP of silicon dioxide

Wafer-scale pressure distributions developed previously are combined with locally relevant models for asperity deformation and contact pressure during chemical mechanical planarization (CMP) based on the Greenwood and Williamson model. This combined model is used to predict local and wafer-scale removal rates. The resulting predictions are compared to wafer-scale experimental data obtained in an IPEC 472 polishing platform. In addition, the model is used to investigate the nature of pad-particle-wafer contact during CMP and its changing nature as a result of variations in abrasive particle diameter, slurry solid weight percentage, and changes in pad surface morphology. It has been established that the model is sensitive to pad surface morphology, in agreement with experimental observations. Two conclusions are drawn: (i) pad topography is a key aspect to be understood and optimized in CMP and (ii) it is necessary to collect pad surface topography data in order to accurately model a CMP material removal process. (C) 2003 The Electrochemical Society.