A method of forming a semiconductor structure that comprises implantation of ions into a material to be etched layer

A method of forming a semiconductor structure comprising: Providing a semiconductor substrate, wherein the substrate is a structural element is formed and having the structural element of a side surface and a top surface; Forming a first material layer over the substrate, wherein the first material layer covering at least the side surface of the structural element; Performing a first ion implantation process to form a first ion-implanted region in the material layer; and Performing a first etching process, which is designed to remove the first ion-implanted region in the first material layer having a greater etching rate than other portions of the first material layer.