Study on polishing performance of single crystal SiC assisted by FeSO4 microcapsules

Single crystal silicon carbide (SiC) ranks among the representative third-generation semiconductor materials. Owing to its superior physical and chemical characteristics, it is regarded as a highly desirable substrate candidate for the preparation of high-power electronic chips. However, the exceptional hardness and outstanding chemical inertness of this material present substantial technical obstacles to the high-efficiency chemical mechanical polishing (CMP) of single crystal SiC substrates. In this work, the Fenton component (FeSO 4 ) in the CMP polishing slurry was encapsulated to form microcapsules. During the polishing process, these microcapsules make contact with the surface of the workpiece and liberate hydroxyl radicals (•OH) characterized by strong oxidizing properties, thereby facilitating efficient interfacial chemical reactions, effectively improving CMP processing efficiency, and extending the useful life of the polishing slurry. First, the influence of different polishing systems on the polishing effect was investigated. Subsequently, how abrasive category, particle size, abrasive concentration, contact pressure, rotational speed, and processing time affect the polishing of single crystal SiC were systematically analyzed. According to the experimental results, under the optimum process conditions—W0.5 CeO 2 abrasive, 1 wt% abrasive concentration, 228.7 kPa contact pressure, 60 rpm rotational speed, and 80 min processing time—high-efficiency and high-quality polishing of single crystal SiC can be achieved. The material removal rate (MRR) is 2.391 μm/h, and the surface roughness (Sa) is 0.617 nm.