Cavitation-driven nanosecond laser irradiation assisted chemical–mechanical-polishing (CMP) for atomic-scale material removal of 4H-SiC

Silicon carbide (SiC) is one of the most promising three-generation semiconductor materials owing to its remarkable properties and numerous potential applications. Nevertheless, the polishing efficiency of hard-to-process single crystal SiC remains a significant challenge due to its high hardness and chemical inertness. A novel approach by employing nanosecond laser irradiation in deionized water as a pre-process for the chemical mechanical polishing (CMP) process was presented. By irradiating the Si-face in transverse and cross-scanning irradiation sequentially, the SiC wafers were processed with CMP using the eco-friendly polishing slurry. The polishing performance of underwater nanosecond laser assisted (UNLA)-CMP, including material removal rate (MRR) and surface roughness (R_a), was evaluated, and the mechanisms of underwater nanosecond laser irradiation of SiC surfaces were investigated. The results indicate that the proposed UNLA-CMP process can meet the various requirements for surface accuracy in the surface polishing of SiC wafers. The study offers a beneficial exploration of applying the post-treatment of underwater nanosecond laser irradiation to the efficient atomic-scale SiC-CMP process.