Dry etching of single-point cutting tool made of nanopolycrystalline diamond using oxygen plasma (Translated) (Shapeable cutting-edge radius)

Dry etching with oxygen plasma was performed on a single-point cutting tool composed of nano-polycrystalline diamond to elucidate the shapeable cutting-edge radius (CER). The tool's CER was measured using an atomic force microscope employing a cantilever made of single-crystal silicon with a tetrahedral shape and a probe tip radius ranging from 4 to 10 nm. The determination of the actual CER involved subtracting the fixed probe tip radius from the measured CER. The dry-etching test results demonstrated a continuous decrease in the measured CER, ultimately converging to a constant value equivalent to the probe tip radius as etching time increased. This phenomenon was utilized to fabricate a standard tool suitable for calibrating the probe tip radius, ensuring a CER and its variation within 0.1 nm. Calibration using the standard tool enabled the identification of the actual CER from the measured values. Notably, the actual CER converged to less than 0.1 nm, with the variation in the converged CER remaining under 0.5 nm. Thus, the shaped actual CER achievable through dry etching with oxygen plasma was less than 0.5 nm.