Temperature controlled showerhead
A temperature controlled showerhead for chemical vapor deposition (CVD) chambers enhances heat dissipation to enable accurate temperature control with an electric heater. Heat dissipates by conduction through a showerhead stem and fluid passageway and radiation from a back plate. A temperature control system includes one or more temperature controlled showerheads in a CVD chamber with fluid passageways serially connected to a heat exchanger.
1. A chandelier-type showerhead comprising:
(a) a stem comprising a convective cooling fluid passageway, a gas delivery passageway, a first end, and a second end opposite the first end, wherein the first end is configured for attachment to a chamber, wherein the convective cooling fluid passageway enters and exits the stem at the first end, and wherein the gas delivery passageway enters the stem at the first end and exits the stem at the second end;
(b) a back plate thermally coupled to the stem at the second end;
(c) a heater physically attached to the back plate;
(d) a face plate thermally coupled to the back plate; and
(e) a temperature sensor for measuring a temperature of the face plate,
wherein the face plate is configured to be removably attached to the back plate via a mating feature and wherein the face plate material is chemical- and plasma-resistant aluminum alloy.
2. The chandelier-type showerhead of claim 1 , wherein the mating feature comprises a circumferential sidewall.
3. The chandelier-type showerhead of claim 1 , wherein the face place further comprises a plurality of small through-holes.
4. The chandelier-type showerhead of claim 3 , wherein the plurality of small through-holes is 3000-4000 through-holes.
5. The chandelier-type showerhead of claim 3 , wherein the plurality of small through-holes form a pattern of non-uniform hole density.
6. The chandelier-type showerhead of claim 3 , wherein the holes in the plurality of small through-holes have a diameter of about 0.01 to 0.5 inch.
7. The chandelier-type showerhead face plate of claim 1 , wherein the thickness of the face plate is about 0.125 to 0.5 inches.
8. The chandelier-type showerhead face plate of claim 1 , further comprising a thermocouple contact hole.
9. The chandelier-type showerhead face plate of claim 1 , wherein the face plate further comprises a plurality of threaded blind holes.
10. The face plate of claim 3 , wherein the plurality of small through-holes is 100 to 10,000 through-holes.
11. The chandelier-type showerhead of claim 9 , further comprising a plurality of spacers, each spacer coupled to one of the threaded blind holes.
12. The chandelier-type showerhead of claim 1 , the stem further comprising a central core and an outer sleeve.
13. The chandelier-type showerhead of claim 12 , wherein the outer sleeve contacts the central core along an exterior surface region of the central core, wherein the convective cooling fluid passageway comprises a channel in the exterior surface region of the central core.
14. The chandelier-type showerhead of claim 13 , wherein the channel is a helical channel wrapped around the central core.
15. The chandelier-type showerhead of claim 13 , wherein the convective cooling fluid passageway further comprises a conduit located within the central core, and wherein the conduit and the channel are fluidly connected at the second end.
16. The chandelier-type showerhead of claim 13 , wherein the gas delivery passageway further comprises tubing routed through the central core.
17. The chandelier-type showerhead of claim 16 , wherein the convective cooling fluid passageway further comprises a conduit located within the central core, and wherein the conduit and the channel are fluidly connected at the second end by an annular volume, wherein the interior diameter of the annular volume is defined by an outer surface of the tubing.
18. The chandelier-type showerhead of claim 13 , wherein the channel has a substantially rectangular cross-section.