Dielectric SiO₂ Planarization Using MnO₂ Slurry

Abstract

MnO2 slurry can polish SiO2 film faster and planarize wide feature steps (2 ×2 mm2) to a lower height than conventional silica slurry. A comparison of Gibbs free energies indicates that the MnO2 abrasive directly reacts on the SiO2 film. In post-Chemical mechanical polishing (CMP), the MnO2 abrasive can be completely removed by dipping it in mixed solutions of inorganic acids and H2O2 followed by scrubbing and dipping in HF solution. A comparison of Gibbs free energies clarifies that the MnO2 abrasive on the wafer is easily dissolved in a mixed solution of an inorganic acid and H2O2.