9Development of New Diamond Slurry, Diamond Disk and Catalyst Etching Mechanical Polishing Method for Polishing Single-Crystal Silicon Carbide

In this study, a novel diamond slurry for mechanical polishing is developed, in which the diamond is heated at different temperatures in a furnace to allow for diamond oxidation to occur; this results in improved diamond surface roughness and sharpness. In addition, a novel catalyst etching mechanical polishing (CEMP) technique is presented, which combines chemical, loose, and fixed polishing methods to improve the polishing process. The surface characteristics, surface damage, and removal rate of silicon carbide (SiC) samples polished with the developed slurry and CEMP are examined and compared with the corresponding attributes yielded by both a conventional diamond slurry and conventional chemical mechanical polishing (CMP). A novel Fe-impregnated polishing pad with a nautilus groove pattern is also developed and used in this study. In addition, we evaluate diamond disks manufactured using polymer-bonded diamond grits, known as polyepoxide combined organic diamond disks (PCDDs). Three kinds of diamond disks are fabricated, containing 600, 1200, and 3000 diamond grits with regular grit distributions, and their performances are compared with that of a traditional 25000-grit diamond disk. The experimental results reveal that the new diamond slurry can yield 4 5 times the material removal rate compared with commercial diamond slurry. Consequently, a mechanical polishing time reduction of more than half is expected. Further, the experimental results also show that the SiC removal rate for CEMP combined with the Fe-impregnated polishing pad is approximately three times higher than that provided by traditional CMP. The surface roughness obtained via CEMP is approximately 1.37 angstrom, which is close to the standard commercial value (1 angstrom). It is found that the PCDD dressing rate is approximately three times that of the traditional diamond disk, whereas the PCDD manufacturing cost is approximately 300% lower. When the proposed process is applied to single-crystal SiC polishing, both the polishing time and the cost are reduced. Therefore, this novel design can facilitate extensive use of well-polished single-crystal SiC wafers in the future.