Implementations described herein generally relate to semiconductor manufacturing and more particularly to the process of plasma etching an amorphous carbon layer. In one implementation, a method of etching a feature in an amorphous carbon layer is provided. The method comprises transferring a substrate including a patterned photoresist layer disposed above the amorphous carbon layer into an etching chamber, exposing the amorphous carbon layer to a fluorine-free etchant gas mixture including a fluorine-free halogen source gas and a passivation source gas and etching the amorphous carbon layer with a plasma of the fluorine-free etchant gas mixture. It has been found that plasma etching with a fluorine-free halogen based gas mixture reduces the formation of top critical dimension clogging oxides.