Study on heterogeneous Fenton reaction parameters for polishing single-crystal SiC using magnetorheological elastomers polishing pads

Abstract

Magnetorheological elastomers (MRE) are intelligent controllable materials used as polishing pads in chemical mechanical polishing (CMP), and the magnetic particles in the MRE polishing pad are used as solid-phase catalysts for heterogeneous Fenton reactions for oxidizing single-crystal SiC surfaces, thereby helping reduce the processing difficulty and obtain high-quality surfaces. The influence of the solid-phase catalyst (Fe3O4 mass fraction, particle size) and polishing solution environment (H2O2 concentration, pH value) on the CMP heterogeneous Fenton reaction polishing single-crystal SiC were investigated. The material removal behavior of the MRE polishing pad was investigated. The results demonstrated that the solid-phase catalyst, Fe3O4, has a better superior effect than the carbonyl iron powder (CIP). The polishing material removal rate (MRR) increased and the surface roughness (Ra ) decreased with an increase in the Fe3O4 mass fraction. Superior polishing results were obtained at a particle size of 0.3 μm. The higher the H2O2 concentration in the polishing solution, the greater the MRR, with lower Ra at 10% concentration. The highest MRR and lowest Ra were achieved at pH = 3 in acidic environments. During polishing, the heterogeneous Fenton reaction can significantly enhance the removal ability of polishing materials. The MRR increased by 33.4% with the heterogeneous Fenton reaction compared with those without the heterogeneous Fenton reaction, and the contribution of the heterogeneous Fenton reaction to total material removal was 25.03%. The analysis of the SiC–Abrasive–MRE polishing pad contact state revealed that the heterogeneous Fenton reaction can oxidize the SiC surface and reduce the surface hardness, increasing the indentation depth δwa of the abrasive grain into the SiC surface and exhibiting greater material removal.