Patent ID: 8137501

Claim:
An apparatus for removing material on a bevel of a wafer with a diameter, comprising: a wafer support with a diameter that is less than the diameter of the wafer, wherein when a wafer is supported by the wafer support, wherein the wafer support is on a first side of the wafer, and an outer edge of the wafer extends beyond the wafer support around the wafer; an RF power source electrically connected to the wafer; a central cover spaced apart from the wafer support so that when the wafer is placed on the wafer support the wafer is placed between the central cover and the wafer support, so that the central cover is on a second side of the wafer; a first electrically conductive ring on the first side of and spaced apart from the wafer; a second electrically conductive ring spaced apart from the wafer, wherein an outer edge of the wafer lies between the first electrically conductive ring and the second electrically conductive ring and wherein the second electrically conductive ring is on the second side of the wafer; an electrically conductive liner surrounding the outer edge of the wafer and spaced apart from the first electrically conductive ring and the second electrically conductive ring; and a switch between the liner and ground, allowing the liner to be switched from being grounded to floating.