Novel reactive chemical mechanical polishing technology for fabrication of SiC mirrors

A new reactive chemical mechanical polishing process has been developed and optimized for polishing CVD SiC mirror samples. The studies show that the abrasives, chemical nature of the slurry, and other additives play an important role in the material removal rate and surface finish of the SiC mirror. The use of different abrasive types and sizes resulted in differing roughness and removal rates. The smaller abrasives created surface defectivity or higher roughness. This can be explained by different polishing rates of different orientations of SiC grains, resulting in the grain enhancement. Under optimal conditions with appropriate abrasive particles, roughness RMS as low as 0.2 nm was achieved on CVD SiC samples. The process also did not show any scratch-like features in the optical interferometry measurements.