Effect of Mn-Based Slurries on Chemical Mechanical Polishing of SiC Substrates

Abstract

High-efficiency and high-quality chemical mechanical polishing (CMP) of silicon carbide (SiC) substrates was achieved using slurries prepared with manganese oxide (MnO2, Mn2O3) particles. Experimental results showed that the oxidation-reduction potential (ORP) and zeta potential of these manganese (Mn)-based slurries decreased with increasing pH. For alkaline pH values (> 7), MnO2 particles were converted into strongly oxidizing MnO4 2− ions that promoted interfacial chemical reactions during CMP, thereby increasing the material removal rate. Observation and analysis of the SiC substrate surface showed that the surface roughness (Ra) reached 1 nm after polishing, but slight surface scratches remained. The binding energy of elemental oxygen (O) and Mn (O1s and Mn2p) indicated that the atoms on the substrate surface underwent an oxidation reaction, which weakened the Si-C molecular bond and thus increased the material removal rate.