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

Abstract

Dry etching using oxygen plasma was conducted on a single-point cutting tool made of nano-polycrystalline diamond to clarify the shapeable cutting edge radius (CER). The CER of the tool was measured by atomic force microscopy (AFM). The cantilever employed was made of single crystal silicon and had a tetrahedral shape with a probe tip radius of 4 to 10 nm. The CER can be identified by subtracting the probe tip radius from a measured CER when the probe tip radius is fixed at a certain value. Dry etching tests revealed that the measured CER decreased and converged to a constant value equivalent to the probe tip radius with increasing etching time. Utilizing this phenomenon, a standard tool suitable for calibrating the probe tip radius was fabricated. The CER and the variation in the CER of the standard tool were less than 0.1 nm. This calibration using the standard tool made it possible to identify the CER from the measured CER. It became clear that the CER converged to less than 0.1 nm, and the variation in converged CER was less than 0.5 nm. Hence, it can be concluded that the shapeable CER that can be formed by dry etching using oxygen plasma is less than 0.5 nm.

Keywords

• dry etching
• oxygen plasma
• single-point cutting tool
• nano-polycrystalline diamond
• cutting edge radius