On the wafer/pad friction of chemical–mechanical planarization (CMP) processes—Part I: Modeling and analysis

Abstract—This paper presents the experimental validation and some application examples of the proposed wafer/pad friction models for linear chemical–mechanical planarization (CMP) pro-cesses in the companion paper. An experimental setup of a linear CMP polisher is first presented and some polishing processes are then designed for validation of the wafer/pad friction modeling and analysis. The friction torques of both the polisher spindle and roller systems are used to monitor variations of the friction coefficient in situ. Verification of the friction model under various process parameters is presented. Effects of pad conditioning and the wafer film topography on wafer/pad friction are experimen-tally demonstrated. Finally, several application examples are presented showing the use of the roller motor current measure-ment for real-time process monitoring and control. Index Terms—Chemical–mechanical planarization (CMP), fric-tion, process modeling and monitoring, shallow trench isolatio