Multi-plenum, dual-temperature showerhead

Patent metadata

Field	Value
Publication number	US-9677176-B2
Application number	US-201313934597-A
Country	US
Kind code	B2
Filing date	Jul 3, 2013
Priority date	Jul 3, 2013
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

A dual-temperature, multi-plenum showerhead for use in semiconductor processing equipment is described. The showerhead may supply multiple separate gases to a wafer reaction area while keeping the gases largely segregated within the showerhead. Additionally, the showerhead may be configured to allow a faceplate of the showerhead to be maintained at a significantly higher temperature than the rest of the showerhead.

First claim

The invention claimed is:

1. A showerhead for use in semiconductor processing equipment, the showerhead comprising:
a first plenum volume;
a second plenum volume;
a faceplate;
a plenum divider;
one or more low-contact-area (LCA) features; and
a first low-thermal-conductance barrier having an inner perimeter, wherein:
the plenum divider has a first side and a second side opposite the first side of the plenum divider,
the faceplate has a first side and a second side opposite the first side of the faceplate,
the first side of the faceplate faces the second side of the plenum divider and is offset from the second side of the plenum divider by a first distance to form a first gap,
the first side of the plenum divider partially bounds the first plenum volume,
the second plenum volume is located between the plenum divider and the faceplate within the first gap,
the plenum divider includes a plurality of tubular structures that protrude from the second side of the plenum divider by a second distance, each tubular structure having an exterior surface and a first through-hole passing through the tubular structure and the plenum divider and into the first plenum volume,
the faceplate includes a plurality of second through-holes passing through the faceplate and into the second plenum volume, each second through-hole corresponding to a different one of the tubular structures and having an interior surface offset from the exterior surface of the corresponding tubular structure by at least a third distance,
the first distance is less than the second distance,
the faceplate is substantially conductively thermally isolated from the plenum divider,
the one or more LCA features support the faceplate with respect to the plenum divider,
the first low-thermal-conductance barrier is interposed between the faceplate and the plenum divider so as to span the first gap, and
the first low-thermal-conductance barrier is positioned such that the second through-holes are located within the inner perimeter of the first low-thermal-conductance barrier.

2. The showerhead of claim 1 , wherein:
the faceplate and the plenum divider are configured to have a thermal conductance of 0.05 W/(in 2 K) or less between them.

3. The showerhead of claim 1 , further comprising a backplate, wherein:
the first plenum volume is also partially bounded by the backplate, and
the backplate includes internal cooling passages and is configured to be actively cooled.

4. The showerhead of claim 1 , wherein the plenum divider includes one or more internal cooling passages configured to circulate coolant within the plenum divider.

5. The showerhead of claim 1 , further comprising a plasma dome connected with a radio frequency generator and fluidly connected with a first gas inlet, wherein:
the first plenum volume is also partially bounded by the plasma dome, and
the plasma dome and RF generator are configured to generate a plasma within the first plenum volume using gas from the first gas inlet.

6. The showerhead of claim 1 , wherein:
the faceplate has a plurality of additional second through-holes in addition to the plurality of second through-holes, and
the additional second through-holes do not have corresponding tubular structures.

7. The showerhead of claim 1 , wherein the tubular structures are substantially cylindrical, the first through-holes and the second through-holes are substantially round, and the offset between the interior surface of each second through-hole and the exterior surface of each corresponding tubular structure results in an annular gap region between the second through-hole and the corresponding tubular structure.

8. The showerhead of claim 1 , wherein the third distance is less than about 0.1″.

9. The showerhead of claim 1 , wherein the third distance is between about 0.005″ and 0.020″.

10. The showerhead of claim 1 , wherein each tubular structure terminates at a location substantially even with the second side of the faceplate proximate to the corresponding second through-hole.

11. The showerhead of claim 1 , further comprising: a first gas inlet; and a second gas inlet, wherein: the first gas inlet is configured to supply gas to the first plenum volume, the second gas inlet is configured to supply gas to the second plenum volume, the second gas inlet is substantially tubular, passes through the plenum divider, and spans between the first side of the faceplate and the second side of the plenum divider, the second gas inlet has a circular array of radial gas distribution holes, each radial gas distribution hole fluidly connecting the second gas inlet with the second plenum volume.

12. The showerhead of claim 1 , wherein the first low-thermal-conductance barrier has a serpentine cross-section in a plane perpendicular to the faceplate with a serpentine length that is greater than the first distance.

13. The showerhead of claim 1 , wherein substantially all of the thermally conductive paths from the faceplate to other components of the showerhead are provided by the one or more LCA features and the first low-thermal-conductance barrier.

14. The showerhead of claim 1 , wherein the one or more LCA features are provided by a plurality of posts spaced about the first low-thermal-conductance barrier, the posts configured to support the faceplate in tension.

15. The showerhead of claim 1 , further including a collar having an interior collar surface that is offset from the faceplate by at least a fourth distance and having an interior aperture smaller than the faceplate, wherein the one or more LCA features are provided by a plurality of LCA balls that support the second side of the faceplate in compression, the LCA balls located between the interior collar surface and the faceplate.

16. The showerhead of claim 1 , further comprising a second low-thermal-conductance barrier having an inner perimeter, wherein:
the second low-thermal-conductance barrier is interposed between the faceplate and the plenum divider so as to span the first gap, and
the first low-thermal-conductance barrier is located within the inner perimeter of the second low-thermal-conductance barrier.

17. The showerhead of claim 16 , wherein substantially all of the thermally-conductive paths from the faceplate to other components of the showerhead are provided by the one or more LCA features, the first low-thermal-conductance barrier, and the second low-thermal-conductance barrier.

18. The showerhead of claim 16 , wherein:
a third plenum volume is at least partially defined by the first side of the faceplate, the second side of the plenum divider, the first low-thermal-conductance barrier, and the second low-thermal-conductance barrier;
the faceplate includes:
a plurality of internal flow passages, and
a plurality of third holes in the first side of the faceplate, wherein:
each third hole spans between one of the internal flow passages and the first side of the faceplate; and
each third hole exits the first side of the faceplate in a region between the first low-thermal-conductance barrier and the second low-thermal-conductance barrier.

19. The showerhead of claim 18 , wherein the first plenum volume, the second plenum volume, and the third plenum volume are all fed from separate gas inlets.

20. The showerhead of claim 18 , wherein the second through-holes intersect the internal flow passages and the second through-holes are thereby in fluidic communication with the internal flow passages within the faceplate.

21. The show

Assignees

• Novellus Systems Inc

Inventors

• Chandrasekharan Ramesh
• Petraglia Jennifer L

Classifications

• C23C16/45574

  Nozzles for more than one gas · CPC title

• B05B1/18

  Roses; Shower heads · CPC title

• C23C16/45565

  Shower nozzles · CPC title

• C23C16/45572 Primary

  Cooled nozzles · CPC title

• C23C16/45568 Primary

  Porous nozzles · CPC title