US Patent 10950434 Methods of reducing gate spacer loss during semiconductor manufacturing

A method includes forming a gate spacer on sidewalls of a dummy gate structure disposed over a semiconductor substrate; performing a first implantation process to the gate spacer, wherein the first implantation process includes bombarding an upper portion of the gate spacer with silicon atoms; after performing the first implantation process, performing a second implantation process to the upper portion of the gate spacer, wherein the second implantation process includes bombarding the upper portion of the gate spacer with carbon atoms; and after performing the second implantation process, replacing the dummy gate structure with a high-k metal gate structure, wherein the replacing includes forming an interlayer dielectric (ILD) layer.