Trajectory uniformity of the double-sided mechanical polishing of SiC single crystal substrate

摘要

SiC single crystal substrate has a useful range of physical, mechanical and electronic properties that makes it a promising material for semiconductor devices. To obtain the relationship between a certain abrasive on the polishing pad and SiC single crystal substrate, the model of double-sided mechanical polishing has been established and the kinematics equations also been derived. As a key to the process, the best optimized polishing trajectory parameters have been carried out. The specific detailed distribution ranges of abrasive distribution radius RA, speed ratio of ring gear to sun gear m and speed ratio of lower polishing disk to sun gear n have been proposed. To acquire the trajectory uniformity of the double-sided mechanical polishing, the coefficient of variation firstly based on statistical analysis has been calculated. Surface quality of the double-sided mechanical polishing of SiC single crystal substrate has been characterized by flatness, micro-morphology and surface roughness (C-face and Si-face). All these results greatly provide a key guarantee for the next step of chemical mechanical polishing to improve efficiency and ensure ultra-precision polishing quality.