Polycrystalline CVD diamond film possesses many outstanding physical and mechanical properties which make it a very important engineering material. However, high hardness value and extreme brittleness have made CVD diamond a very difficult material to be machined by conventional grinding and polishing process. In this present study, the diamond wafer was pre-treated with RIE before it was thermo-chemically polished. It was found when diamond wafer was ion-etched in O2 (25 min, 200W, 50sccm), the top layer pyramidal diamond crystals were anisotropically etched into micro-pillar structures. These micro-pillars have significantly weakened the structure of diamond grains and paved the way for subsequent thermo-chemical polishing. Based on the obtained results, this method has great potential to be applied to speed up the polishing process of CVD diamond films in the future.
