Investigation of Fenton-electrochemical oxidation behavior and polishing mechanism of SiC

SiC is applied extensively in semiconductor fields because of outstanding characteristics. Nevertheless, its high hardness and chemical inertness hinder the polishing before application. This article introduces the Fenton reaction, ultrasound, and electrochemistry in SiC polishing. The effects of voltage, pH, and downward pressure on ultrasonic-assisted electrochemical mechanical polishing (UAECMP) are investigated through experiments and tests. The optimal polishing parameters have been determined: voltage of 3 V, pH 10, and downward pressure of 8 psi. The MRR of SiC is nearly 4.5 times that of conventional CMP. The polished surface roughness is Ra 0.127 nm. In addition, the polishing mechanism is studied through polarization curves, EIS, XPS, Zeta potential, and abrasive size. A material removal model of SiC UAECMP is put forward. It is helpful to develop new polishing technology of SiC and improve the machining efficiency and quality.