Study on the Mechanism of Chemical Mechanical Polishing for 4H-SiC Based on Photoelectro-Fenton Reaction

Abstract In order to meet the requirements of atomic-level smoothness and non-damaging wafer surface with a high material removal rate (MRR) of silicon carbide (SiC), a new method assisted by photoelectron-Fenton reaction was studied to assist in chemical mechanical polishing. The coupling effects of ultraviolet light, electric field, and Fenton reaction in improving the slurry oxidation performance and the oxidation ability on the 4H-SiC wafer surface has been verified by measuring the oxidation-reduction potential, using probe detection methods, and conducting electrochemical experiments. Through immersion oxidation experiments, the oxidation mechanisms of SiC wafers were analyzed in depth using scanning electron microscope, energy-dispersive spectrometry, and X-ray photoelectron spectroscopy tests. The results showed that the photoelectro-Fenton reaction greatly enhanced the oxidation ability of the slurry, which improved the efficiency of oxide layer generation on the wafer surface. The high MRR of 102.4 nm/h and the low surface roughness (Ra) of 0.57 nm can be obtained after polishing under the condition of pH = 3, and the polishing and synergistic mechanism of 4H-SiC in the photoelectron-Fenton reaction solution was proposed.