Patent ID: 9230778
Filing Date: 2016-01-05
CPC Classification: C23C,H01J,H01L

Claim Text:
1. Process for reactive de-coating of carbon layers deposited by means of PVD or CVD methods on a substrate, the process being particularly suitable for the reactive removal of ta-C coatings from the surface of parts and tools, the process comprising the steps: placing the substrate to be de-coated on a substrate holder in a vacuum chamber, charging the vacuum chamber with at least one reactive gas for supporting the stripping of the carbon layers which are to be stripped in gaseous form, initiating a plasma discharge in the vacuum chamber for forming a plasma of the reactive gas for supporting the necessary chemical reaction or reactions to produce a reactive stripping of the carbon layers in gaseous form from the substrate to be de-coated, conducting the reactive stripping in one or more steps, characterized in that the plasma discharge is produced as a low voltage direct current arc discharge, with discharge current between 20 A and 1000 A and with discharge voltage of at most 120 V, and during the at least one step of the reactive stripping: a gas containing nitrogen is used as the reactive gas, and the reactive gas used comprises predominantly nitrogen, and the substrate to be de-coated is connected as an anode for the low voltage direct current arc discharge, and thereby the surface of the substrate to be de-coated is bombarded essentially exclusively with electrons, so that at least a portion of the carbon layers is removed from the substrate to be de-coated without producing any sputtering of the carbon layers.