Synergistic Effect of Photocatalysis and Fenton on Improving the Removal Rate of 4H-SiC during CMP

To improve the material removal rate (MRR) of single-crystal silicon carbide (SiC) by chemical mechanical polishing (CMP), an ultraviolet (UV) photocatalysis–Fenton (UV + TiO ₂ + Fenton) composite reaction is used to increase the hydroxyl radical (·OH) concentration. In this study, the effects of UV photocatalysis, the Fenton reaction, and their composite reaction on ·OH concentration are experimentally investigated by the chemical degradation of methyl orange. Subsequently, the oxidation–reduction potential (ORP) during the reaction is measured to characterize the oxidisability of the chemical reaction. Finally, a CMP experiment is conducted to verify the synergistic effect of the UV + TiO ₂ + Fenton composite reaction. The ·OH test results show that the ·OH concentration in the UV + TiO ₂ + Fenton composite reaction is relatively significantly improved. They are 6 and 1.38 times those obtained in the Fenton and UV + TiO ₂ + H ₂ O ₂ systems, respectively, and 11.4% higher than the summations of these properties achieved in both the systems. The CMP experiment results show that the MRR reaches 387.2 nm h ⁻¹ when the single-crystal 4H-SiC is polished by the UV + TiO ₂ + Fenton system, which is 44.1% and 22.4% higher than those of the Fenton and UV + TiO ₂ + H ₂ O ₂ systems, respectively. The synergistic mechanism of the UV + TiO ₂ + Fenton composite reaction system for CMP is discussed.