An apparatus for etching an edge of a wafer includes a chamber, a chuck disposed inside the chamber upon which the wafer is disposed, a plate spaced apart from the wafer and disposed above the wafer, and an edge ring formed along the edge of the wafer and combined with an outer periphery of the plate, wherein the edge ring comprises a ring base spaced a distance apart from the wafer to form a parallel plane with respect to the wafer, and a first ring protrusion protruding from the ring base to insulate the edge of the wafer from a central region of the wafer.