Electrostatic chuck for use in semiconductor processing

A semiconductor substrate processing apparatus includes: a vacuum chamber having a processing region in which a semiconductor substrate can be processed; a process gas source in fluid communication with the vacuum chamber to supply process gas into the vacuum chamber; a showerhead module through which a process gas is supplied from the process gas source to the processing region of the vacuum chamber; and a substrate pedestal module. The substrate pedestal module includes a platen made of a ceramic material, the platen having an upper surface configured to support a semiconductor substrate thereon during processing; a shaft made of a ceramic material; and coplanar electrodes embedded in the platen, the electrodes including an outer RF electrode and an inner electrostatic clamping electrode, the outer RF electrode including a ring electrode and a radially extending wire extending from the ring electrode to a central portion of the platen, wherein the ceramic material of the platen and the electrode comprise a