High ac current high rf power ac-rf decoupling filter for plasma reactor heated electrostatic chuck

Abstract

An RF blocking filter isolates a two-phase AC power supply from at least 2 kV p-p of power of an HF frequency that is reactively coupled to a resistive heating element, while conducting several kW of 60 Hz AC power from the two-phase AC power supply to the resistive heating element without overheating, the two-phase AC power supply having a pair of terminals and the resistive heating element having a pair of terminals. The filter includes a pair of cylindrical non-conductive envelopes each having an interior diameter between about one and two inches and respective pluralities of fused iron powder toroids of magnetic permeability on the order of about 10 stacked coaxially within respective ones of the pair of cylindrical envelopes, the exterior diameter of the toroids being about the same as the interior diameter of each of the envelopes. A pair of wire conductors of diameter between 3 mm and 3.5 mm are helically wound around corresponding ones of the pair of envelopes to form respective inductor windings in the range of about 16 to 24 turns for each the envelope, each of the conductors having an input end and an output end. The input end of each one of the conductors is coupled to a corresponding one of the pair of terminals of the two-phase AC power supply, and the output end of each one of the conductors is coupled to a corresponding one of the pair of terminals of the resistive heating element.