The present disclosure relates to methods for improving adhesion between a hardmask layer and a subsequent layer on the hardmask layer. Particularly, embodiment of the present disclosure relates to methods for improving adhesion between a metal-doped amorphous carbon layer and a mask layer, such as a silicon oxide layer, a silicon nitride layer, or an amorphous silicon layer. One embodiment of the present disclosure includes performing a plasma treatment to the metal-doped amorphous carbon layer.