Surface modulation to enhance chemical mechanical polishing performance of sliced silicon carbide Si-face

Ultra-precision machining of silicon carbide (SiC) Si-face has been one of the difficulties in manufacture. Various new processing methods were proposed, targeting to address the issue. However, mechanism of surface structure and composition changes effects on machining performance were still unclear. In this study, the structure with different cluster size and oxide content is prepared on SiC Si-face by nanosecond laser modulation. Benefiting from the increased content of oxygen and the consistency of oxide composition on the surface/subsurface, the stability of the removal rate (MRR) in the continuous chemical mechanical polishing (CMP) is improved, resulting in advanced removal efficiency. Additionally, the oxide coating on the SiC surface reduces the probability of contact between abrasives and SiC Si-surface, leading to minor scratches after polishing. The roughness (Ra) is as low as 0.081 nm polished with alumina (Al2O3) slurry. Remarkably, it is found that the change of oxide content is closely related to MRR of CMP, which provides a new perspective for the design of high-performance SiC Si-face ultraprecision manufacturing.