Patent ID: 8864935

Claim:
A remote plasma generator configured to generate plasma for ashing a large diameter substrate, comprising: a conical upper portion comprising a narrow end and a wide end; a gas flow tube comprising a top end and a bottom end, the top end of the gas flow tube attached to and capping the wide end of the conical upper portion, a part of the gas flow tube and a part of the conical upper portion being continuously surrounded by a symmetrical coil, the symmetrical coil connected to a first capacitor at one end of the symmetrical coil and to a second capacitor at the other end of the symmetrical coil; a gas distribution nozzle attached to the narrow end of the of the conical upper portion, the gas distribution nozzle comprising a hemispherical tip having a first plurality of through holes configured for preferentially directing an incoming flow of gas along sidewalls of the conical upper portion and toward sidewalls of the gas flow tube, the first plurality of through holes further configured to form a region of higher gas density to provide higher plasma density inside the plasma generator proximate an interface between the conical upper portion and the gas flow tube than in regions not proximate the interface between the conical upper portion and the gas flow tube; and a gas distribution plate attached to the bottom end of the gas flow tube, the gas distribution plate comprising a second plurality of through holes for distributing and directing an outgoing flow of the gas out of the plasma generator and to the substrate positioned outside of the remote plasma generator, the gas distribution plate having a diameter substantially the same as the substrate.