Gas distribution plate for thermal deposition
Apparatus and methods for providing high velocity gas flow showerheads for deposition chambers are described. The showerhead has a faceplate in contact with a backing plate that has a concave portion to provide a plenum between the backing plate and the faceplate. A plurality of thermal elements is within the concave portion of the backing plate and extends to contact the faceplate.
1. A gas distribution backing plate comprising a front surface and a back surface defining a thickness, the front surface having a concave portion with a concave surface, a plurality of thermal elements extend from the concave surface to a front surface of the thermal element, each of the front surfaces of the thermal elements are substantially coplanar.
2. The gas distribution backing plate of claim 1 , wherein each of the thermal elements has a tapered profile with a flared base at the concave surface of the concave portion and a narrower end at the front surface.
3. The gas distribution backing plate of claim 1 , wherein the backing plate has an outer peripheral edge and the concave portion has an outer peripheral edge.
4. The gas distribution backing plate of claim 3 , wherein an outer front face ring defined as the front surface of the backing plate between the outer peripheral edge of the concave portion and the outer peripheral edge of the backing plate is substantially flat.
5. The gas distribution backing plate of claim 4 , wherein the front surface of the backing plate at the outer front face ring is substantially coplanar with the front surfaces of the thermal elements.
6. The gas distribution backing plate of claim 4 , wherein the concave portion has a concave portion diameter D C less than an outer peripheral diameter D P of the backing plate to provide a sealing surface at the outer front face ring.
7. The gas distribution backing plate of claim 6 , wherein the concave portion diameter D C is greater than or equal to about 70% of the outer peripheral diameter D P .
8. The gas distribution backing plate of claim 1 , wherein the backing plate further comprises a gas inlet providing fluid communication between the back surface of the backing plate and the concave surface.
9. The gas distribution backing plate of claim 8 , wherein the gas inlet is at a center of the concave surface.
10. The gas distribution backing plate of claim 9 , wherein thermal elements located equidistant from the center have substantially the same length.
11. The gas distribution backing plate of claim 8 , wherein the back surface of the backing plate comprises a groove formed around the gas inlet.
12. The gas distribution backing plate of claim 1 , wherein the backing plate further comprises a thermal control component within a body of the backing plate to control a temperature of the backing plate and faceplate.
13. The gas distribution backing plate of claim 1 , wherein each of the thermal elements has a substantially uniform diameter from the concave portion to the front surface.
14. The gas distribution backing plate of claim 13 , wherein the thermal elements extend directly from the concave surface, creating a hard angle at a point of extension from the concave surface.
15. The gas distribution backing plate of claim 13 , wherein the thermal elements have a radiused portion at the portion of the thermal element at the concave portion so that the transition from the concave portion to a sidewall of the thermal element is slightly tapered.
16. The gas distribution backing plate of claim 1 , wherein the thermal elements have an elongate profile having a smaller cross-sectional area perpendicular to a flow of gas from a center of the concave portion.
17. The gas distribution backing plate of claim 16 , wherein the thermal elements have one or more of a diamond-like shape in which an inner edge of the thermal element faces the center.
18. The gas distribution backing plate of claim 16 , wherein the thermal elements have a prolate spheroid shaped profile with a distinct inner edge and outer edge and curved surfaces connecting the inner edge to the outer edge.