Investigation of increased removal rate during polishing of single-crystal silicon carbide

The application field of silicon carbide (SiC) as a next-generation compound semiconductor is expanding because of its significant advantages: high power, high frequency, low coefficient of thermal expansion, and high thermal conductivity. Many researchers have investigated SiC polishing for the manufacturing of semiconductor substrates using SiC. However, because SiC is a chemically and mechanically stable material, these researchers have faced difficulties due to its very low polishing rate (95–540 nm/h). Therefore, methods are required for increasing the material removal rate of SiC. The aim of this study was to investigate the increase in removal rate during the polishing of single-crystal SiC subjected to simultaneous polishing and dressing by using a diamond-impregnated polishing pad. Two types of pads—containing 1 and 5 wt% nanodiamond—were fabricated, and their performances were compared with that of a polyurethane polishing pad. A novel arrangement of conditioners was created in brazed diamond patterns, which were radially arranged in a cluster with 3–4 grits per cluster. Furthermore, a combined diamond disk was developed. The surface characteristics of the nanodiamond-impregnated pads, as well as the surface roughness, surface damage, and removal rate of the SiC polished with these pads and diamond disks, were investigated and compared with the corresponding attributes displayed by a polyurethane polishing pad and a conventional diamond disk. Experimental results showed that the removal rate of SiC with dressing was approximately 73 % higher than that of without dressing. The novel conditioner resulted in a dressing rate approximately two times higher and a removal rate approximately 38 % higher than those obtained by using the conventional diamond disk. In addition, SiC polishing tests revealed that the nanodiamond-impregnated polishing pads provided better surface roughness with no damage, as well as a removal rate approximately 2.5 times higher than that provided by the polyurethane polishing pad.