Hybrid ceramic showerhead

1. A gas distributor comprising:

a ceramic faceplate for a substrate processing showerhead of a processing chamber, the ceramic faceplate including a first pattern of first through-holes;

an electrode including a second pattern of second through-holes; and

a contact ring having one or more standoffs, wherein the contact ring and the one or more standoffs are all electrically conductive and electroconductively coupled with one another, wherein:

the electrode is embedded within the ceramic faceplate,

the second pattern matches the first pattern,

the first pattern includes all of the holes through which processing gases flow through the ceramic faceplate when the ceramic faceplate is installed in the substrate processing showerhead of the processing chamber,

each second through-hole is larger in size than the corresponding first through-hole,

the contact ring encircles the first pattern of first through-holes,

the ceramic faceplate includes one or more blind standoff apertures that terminate at the electrode,

each standoff extends into a respective blind standoff aperture and is in electrically conductive contact with the electrode, and

the electrode forms either an anode or a cathode of an RF plasma generation system when the ceramic faceplate is installed in the substrate processing showerhead of the processing chamber.

2. The gas distributor of claim 1 , wherein the ceramic faceplate is configured to be removable from the substrate processing showerhead without requiring removal of the substrate processing showerhead from the processing chamber.

3. The gas distributor of claim 1 , wherein each second through-hole has a diameter that is at least the larger of:

the diameter of the corresponding first through-hole plus 0.04″, and

twice the diameter of the corresponding first through-hole.

4. The gas distributor of claim 1 , wherein the first through-holes have diameters of approximately 0.05″.

5. The gas distributor of claim 1 , wherein the first through-holes have diameters of between 0.02″ to 0.06″.

6. The gas distributor of claim 1 , wherein the electrode is embedded within the ceramic faceplate at a depth of approximately 0.05″ from a face of the ceramic faceplate which faces away from an interior plenum volume of the substrate processing showerhead when the ceramic faceplate is installed in the substrate processing showerhead.

7. The gas distributor of claim 1 , wherein the electrode is approximately 0.002″ thick.

8. The gas distributor of claim 1 , wherein the electrode is fully encased by ceramic material of the ceramic faceplate with the exception of one or more electrical contact patches located on a side of the electrode which faces towards an interior plenum volume of the substrate processing showerhead when the ceramic faceplate is installed in the substrate processing showerhead.

9. The gas distributor of claim 8 , further comprising one or more electrically-conductive pathways, wherein:

the one or more electrically-conductive pathways includes at least the contact ring, and

at least a portion of the electrically-conductive pathways is exposed to provide an electrically-conductive contact interface with an electrode power or ground source of the substrate processing showerhead.

10. The gas distributor of claim 9 , further comprising a DC voltage source, the DC voltage source electrically connected to the electrically-conductive contact interface.

11. The gas distributor of claim 10 , wherein the DC voltage source is configured to supply one or more DC voltages between 0 and 200 volts.

12. The gas distributor of claim 1 , further comprising a backplate, wherein:

the backplate is part of the substrate processing showerhead,

the backplate is configured to mechanically interface with the contact ring,

the backplate is configured to mechanically interface with a gas distribution stem or stem sleeve of the substrate processing showerhead, and

the backplate forms an electrically-conductive pathway from the contact ring to the gas distribution stem or stem sleeve.

13. The gas distributor of claim 1 , wherein:

the ceramic faceplate includes a mechanical interface located near the center of the ceramic faceplate and configured to mate with a complementary mechanical interface of a gas distribution stem of the substrate processing showerhead, and

when the ceramic faceplate is installed in the substrate processing showerhead, the mechanical interface and the complementary mechanical interface are mated together and the gas distribution stem, via the mated mechanical interface and complementary mechanical interface, supports the center of the ceramic faceplate.

14. The gas distributor of claim 13 , further comprising the gas distribution stem and a gas distribution stem sleeve, wherein:

the gas distribution stem is mated with the gas distribution stem sleeve via a sliding interface,

the sliding interface includes a spring which constrains sliding movement of the gas distribution stem with respect to the gas distribution stem sleeve,

the gas distribution stem sleeve and the ceramic faceplate are substantially fixed in space relative to each other and with respect to movement along the sliding interface direction of travel, and

the amount of support provided to the center of the ceramic faceplate is governed by displacement of the spring.

15. The gas distributor of claim 1 , wherein:

the contact ring includes interface features which are configured to rigidly connect the contact ring with a substrate processing showerhead, and

the one or more standoffs support the contact ring with respect to the ceramic faceplate and vice-versa.

16. The gas distributor of claim 15 , wherein the interface features are selected from the group consisting of: a threaded interface formed about a circumference of the contact ring, a bayonet mount formed about the circumference of the contact ring, and a pattern of threaded fastener features spaced about the circumference of the contact ring.

17. The gas distributor of claim 1 , further comprising an RF collar, wherein the RF collar is made of an electrically-conductive material and includes:

a thin-walled hoop of a larger diameter than the ceramic faceplate and a smaller diameter than an interior diameter of the contact ring;

a plurality of inner collar tabs, each inner collar tab:

protruding from the thin-walled hoop towards the ceramic faceplate,

overlapping with the ceramic faceplate, and

substantially parallel to a plane normal to a central axis of the thin-walled hoop; and

a plurality of outer collar tabs, each outer collar tab:

protruding from the thin-walled hoop away from the ceramic faceplate,

overlapping with the contact ring, and

substantially parallel to the plane normal to the central axis of the thin-walled hoop.

18. The gas distributor of claim 17 , wherein the thin-walled hoop is formed from one or more segments arranged end-to-end to form an overall hoop shape.

19. The gas distributor of claim 17 , wherein each outer collar tab is located approximately halfway between neighboring pairs of inner collar tabs about the RF collar's circumference.

20. The gas distributor of claim 17 , wherein each inner collar tab is located approximately halfway between neighboring pairs of outer collar tabs about the RF collar's circumference.

21. The gas distributor of claim 1 , further comprising at least one heater element, wherein the at least one heater element:

is embedded within the ceramic faceplate,

is not in electrical contact with the electrode,

follows a path which does not intersect any of the first through-holes, and

maintains a minimum distance from each first through-hole of at least the larger of 0.04″ and the radius of the first through-hole.

22. The gas distributor of claim 1 , further comprising a heater element embedded within the ceramic faceplate, the heater element substantially encircling the first pattern of first through-holes and located in close proximity to an outermost nominal diameter of the ceramic faceplate.

23. The gas distributor of claim 1 , further comprising:

the processing chamber;

the substrate processing showerhead;

and

a pedestal, wherein the substrate processing showerhead, the ceramic faceplate, and the pedestal are located substantially within the processing chamber.

24. The gas distributor of claim 23 , further comprising a gas distribution stem with a first end and a second end, wherein:

the first end is opposite the second end on the gas distribution stem,

the first end of the gas distribution stem is connected with a top of the processing chamber,

the second end of the gas distribution stem is connected to the substrate processing showerhead, and

the ceramic faceplate is removable from the substrate processing showerhead without removing the gas distribution stem from the top of the processing chamber.