Study on the surface polishing with large area plasma modification for 4H-SiC wafer

In this study, the atmospheric plasma assisted polishing technology combining the CMP process and large area atmospheric pressure plasma modification process is investigated for 4 inch 4H-SiC wafers to enhance MRR and improve surface quality. The Si-C bond of SiC material is effectively modified to Si-O bond on the surface of the SiC wafers processed by the irradition of the atmospheric plasma. Comparing with and without the plasma modification, the MRRs of C face and Si face of 4H-SiC wafer are increased about 5.7 and 6.25 times, respectively. The finished surface of the 4H-SiC wafer is near defect-free and the average surface roughness is less than 1 nm. Obviously, the atmospheric plasma assisted polishing technology with large area plasma midification process can be simultaneously obtain high MRR and fine surface quality.