| CPC C23C 16/45565 (2013.01) [C23C 16/4557 (2013.01); C23C 16/45572 (2013.01); H01J 37/3244 (2013.01)] | 18 Claims |

|
1. An apparatus comprising:
a showerhead that includes:
a faceplate;
a backplate;
a gas distribution plenum interposed between the faceplate and the backplate;
a stem including a gas inlet;
one or more heater elements;
an inner cooling channel;
an outer cooling channel; and
a cooling plate assembly, wherein:
the stem is supported by the cooling plate assembly and extends from the cooling plate assembly along a center axis,
the one or more heater elements are located at least partially within the stem and extend at least along a direction parallel to the center axis,
the cooling plate assembly includes at least the outer cooling channel,
the outer cooling channel extends around the inner cooling channel when viewed along the center axis,
the inner and outer cooling channels both extend around the one or more heater elements when viewed along the center axis,
the cooling plate assembly includes a plurality of through-holes,
the stem includes a plurality of threaded holes in a top face of the stem,
each threaded hole in the plurality of threaded holes is aligned with one of the through-holes in the plurality of through-holes in the cooling plate assembly,
the top face of the stem is butted up against a bottom face of the cooling plate assembly,
a corresponding clamping fastener is inserted through each through-hole of the plurality of through-holes in the cooling plate assembly and threaded into the threaded hole in the plurality of threaded holes in the stem aligned therewith,
counterbores exist in one or both of the top face of the stem and the bottom face of the cooling plate assembly, and
each counterbore is centered on one of the through-holes in the plurality of through-holes through the cooling plate assembly.
|