Effects of chemical action of polishing medium on the material removal of SiC

The chemical action mechanism in the chemical mechanical polishing of SiC substrate remains elusive, which has great limitations on the selection of polishing solution and polishing parameters. In this paper, the cutting process of unreacted SiC (U-SiC) and the SiC reacted with H2O (R-SiC-H2O) and H2O2 (R-SiC-H2O2) was studied with an individual diamond abrasive particle by molecular dynamics simulation. The influence of chemical reaction and cutting speed on the material removal of SiC was explored by focusing on the removal rate, surface quality, machining temperature and machining stress. The simulation results showed that the number of removed atoms increased, and the surface roughness and subsurface damage depth decreased for SiC at the same cutting speed after the chemical action. Although the number of removal atoms increased with the increase of cutting speed, the surface roughness and subsurface damage depth increased at the same time. The effects of the polishing medium on the material removal process for SiC can be attributed to the decrease of surface hardness and Si-C bonding energy after the reaction of the polishing medium and SiC. The results provide a guidance for the selection of chemical mechanical polishing systems and machining parameters.