Oxygen plasma etching of diamond-like carbon coated mold-die for micro-texturing

Diamond-like carbon (DLC) coating via PVD/CVD on the SKD11 substrate was employed to make micro-texturing by using high density oxygen plasma etching. Original pattern by metal chromium was first line-drawn on the surface of DLC coating; then, it was subjected to oxygen plasma etching. Even without any hazardous etchants such as CF4, high etching rate was attained only by using oxygen gas; i.e. 5 μm/H. Plasma diagnosis by spectroscopy proved that this etching process should be controlled by activated oxygen atom flux of {O, O*}. Direct chemical reaction by C (in DLC) + O → CO, or, C (in DLC) + O* → CO, drove this etching process. Detection of CO peaks in the wave length range from 200 to 300 nm also proved that this oxygen plasma etching should be advanced by chemical reactions. This etching behavior was insensitive to line width (WG) and pitch width (PG) for 2 μm < WG < 100 μm and 5 μm < PG < 100 μm. Scanning electron microscope and laser-profilometer were also used to make precise measurement on the etched profiles.