Protection Layer Formation during Plasma Etching Conductive Materials

A method of processing a substrate that includes: forming a patterned hardmask layer over a conductive layer to be etched, the conductive layer disposed over a substrate; and patterning the conductive layer using the patterned hardmask layer as an etch mask, by performing a cyclic plasma etch process to gradually form a recess in the conductive layer, each cycle of the cyclic plasma etch process including exposing the substrate to a first plasma including a halogen to etch the conductive layer, and exposing the substrate to a second plasma including a silicon-containing precursor to deposit a silicon-containing protective layer over a top surface of the patterned hardmask layer.