CPC C23C 16/45565 (2013.01) [H01J 37/32743 (2013.01); H01J 2237/332 (2013.01); H01J 2237/334 (2013.01)] | 18 Claims |
1. A showerhead for a substrate processing system, the showerhead comprising:
an upper surface;
a lower surface;
a gas plenum defined between the upper surface and the lower surface;
a plurality of through holes that extend from the upper surface to the lower surface, wherein the plurality of through holes comprise a plurality of first through holes and a plurality of nominal through holes, wherein diameters of the first through holes are different than diameters of the nominal through holes, wherein the plurality of through holes is in fluid communication with volume above the upper surface and a volume below the lower surface;
a plurality of injectors distributed on the lower surface, wherein (i) the plurality of injectors is in fluid communication with the gas plenum such that gas exits from the gas plenum inside the showerhead through the plurality of injectors and (ii) the plurality of injectors does not extend through the upper surface; and
a plurality of gas injector nozzles that extend downward from the lower surface, the plurality of gas injector nozzles aligned with and extending from respective ones of the injectors such that gas exits from the plurality of gas injector nozzles to a volume below the showerhead, wherein, on the lower surface of the showerhead, the plurality of through holes is located in a plurality of separate groups each comprising three through holes distributed in a triangular pattern around a respective one of the plurality of injectors;
wherein the plurality of first through holes comprise a primary type of through holes that have a first diameter, a secondary type of through holes that have a second diameter, and a tertiary type of through holes that have a third diameter, wherein an average diameter of the primary type of through holes satisfies a first predetermined ratio relative to an average diameter of the nominal through holes (Davg_primary)4/(Davg_nominal)4, wherein an average diameter of the secondary type of through holes satisfies a predetermined ratio relative to the average diameter of the nominal through holes (Davg_secondary)4/(Davg_nominal)4, and wherein an average diameter of the tertiary type of through holes satisfies a predetermined ratio relative to the average diameter of the nominal through holes (Davg_tertiary)4/(Davg_nominal)4.
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