Rf plasma method

Abstract

An RF plasma etch reactor having an etch chamber with electrically conductive walls and a protective layer forming the portion of the walls facing the interior of the chamber. The protective layer prevents sputtering of material from the chamber walls by a plasma formed within the chamber. The etch reactor also has an inductive coil antenna disposed within the etch chamber which is used to generate the plasma by inductive coupling. Like the chamber walls, the inductive coil antenna is constructed to prevent sputtering of the material making up the antenna by the plasma. The coil antenna can take on any configuration (e.g. location, shape, orientation) that is necessary to achieve a desired power deposition pattern within the chamber. Examples of potential coil antenna configurations for achieving the desired power deposition pattern include constructing the coil antenna with a unitary or a segmented structure. The segmented structure involves the use of at least two coil segments wherein each segment is electrically isolated from the other segments and connected to a separate RF power signal. The unitary coil antenna or each of the coil segments can have a planar shape, a cylindrical shape, a truncated conical shape, a dome shape, or any combination thereof. The conductive walls are electrically grounded to serve as an electrical ground (i.e. anode) for a workpiece-supporting pedestal which is connected to a source of RF power to create a bias voltage at the surface of the workpiece.