Gas distribution showerhead for inductively coupled plasma etch reactor

Patent metadata

Field	Value
Publication number	US-9934979-B2
Application number	US-201514800850-A
Country	US
Kind code	B2
Filing date	Jul 16, 2015
Priority date	May 31, 2011
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

A two piece ceramic showerhead includes upper and lower plates which deliver process gas to an inductively coupled plasma processing chamber. The upper plate overlies the lower plate and includes radially extending gas passages which extend inwardly from an outer periphery of the upper plate, axially extending gas passages in fluid communication with the radially extending gas passages and an annular recess forming a plenum between the upper and lower plates. The lower plate includes axially extending gas holes in fluid communication with the plenum. The upper plate can include eight radially extending gas passages evenly spaced around the periphery of the upper plate and the lower plate can include inner and outer rows of gas holes. The two piece ceramic showerhead forms a dielectric window of the chamber through which radiofrequency energy generated by an antenna is coupled into the chamber. A gas delivery system delivers process gas to a plenum between the upper and lower plates having a gas volume of no greater than 500 cm 3 . The gas holes in the lower plate extend between the plenum and a plasma exposed yttria coated surface of the lower plate. The gas delivery system is operable to supply an etching gas and a deposition gas into the processing chamber such that the etching gas in the plenum can be replaced with the deposition gas within about 200 milliseconds and vice versa.

First claim

We claim:

1. A lower plate of a ceramic showerhead assembly useful in an inductively coupled plasma processing apparatus wherein semiconductor substrates supported on a substrate support are subjected to plasma etching, the lower plate comprising:
a lower surface having a lower central portion and a lower outer portion;
a stepped upper surface having an upper central portion and an upper outer portion, wherein the upper central portion is thicker than the upper outer portion, wherein the upper outer portion includes an annular zone, and wherein the upper central portion is stepped up from the upper outer portion; and
a plurality of gas holes located in the annular zone and axially extending between the stepped upper surface and the lower surface;
wherein the lower surface includes a lower vacuum sealing surface located on the lower outer portion; and
wherein the upper outer portion includes inner and outer upper vacuum sealing surfaces defining the annular zone.

2. The lower plate of claim 1 wherein the lower plate is made of ceramic material.

3. The lower plate of claim 1 wherein the lower central portion is thicker than the lower vacuum sealing surface.

4. The lower plate of claim 1 , wherein the plurality of gas holes include at least two concentric rings of gas holes.

5. The lower plate of claim 4 , wherein each of the at least two concentric rings includes 20 to 50 gas holes.

6. The lower plate of claim 1 , wherein the lower plate has a diameter of about 20 inches, a thickness of about 1.5 inches at the upper central portion and a thickness of about 0.8 inch at the upper outer portion.

7. The lower plate of claim 5 , wherein the at least two concentric rings of gas holes include an inner ring of 32 gas holes having diameters of about 0.04 inch and located about 5 inches from a center of the lower plate and an outer ring of 32 gas holes having diameters of about 0.04 inch and located about 6.5 inches from the center of the lower plate.

8. The lower plate of claim 1 , wherein the lower vacuum sealing surface is located on a step in the lower outer portion.

9. The lower plate of claim 8 , wherein the step has a depth of about 0.4 inch and a width of about 1.2 inches.

10. The lower plate of claim 1 , wherein the lower plate is made of high purity alumina and the lower surface includes a coating of high purity yttria covering all of the lower surface except the lower vacuum sealing surface.

11. The lower plate of claim 1 , wherein the upper central portion includes a blind hole configured to receive a temperature sensor adapted to monitor temperature of the lower plate when mounted in the ceramic showerhead assembly.

12. The lower plate of claim 1 , wherein the lower plate is further configured to couple to an upper plate.

13. A lower plate of a ceramic showerhead assembly useful in an inductively coupled plasma processing apparatus wherein semiconductor substrates supported on a substrate support are subjected to plasma etching, the lower plate comprising:
a lower surface having a lower central portion and a lower outer portion;
a stepped upper surface having an upper central portion and an upper outer portion, wherein the upper central portion is thicker than the upper outer portion, wherein the upper outer portion includes an annular zone; and
a plurality of gas holes located in the annular zone and axially extending between the stepped upper surface and the lower surface;
wherein the lower surface includes a lower vacuum sealing surface located on the lower outer portion;
wherein the upper outer portion includes inner and outer upper vacuum sealing surfaces defining the annular zone;
wherein the lower plate is further configured to couple to an upper plate; and
wherein the upper plate includes an upper surface, a lower surface, a first plurality of gas passages extending radially and inwardly from an outer periphery of the upper plate, an annular opening, an annular zone surrounding the annular opening and recessed from the lower surface, and a second plurality of gas passages extending axially from the annular zone to the first plurality of gas passages.

14. The lower plate of claim 12 , wherein the lower plate is configured to couple to the upper plate by vacuum forces.

15. An upper plate of a ceramic showerhead assembly useful in an inductively coupled plasma processing apparatus wherein semiconductor substrates supported on a substrate support are subjected to plasma etching, the upper plate comprising:
an upper surface;
a lower surface;
a first plurality of gas passages extending radially and inwardly from an outer periphery of the upper plate;
an annular opening;
an annular zone surrounding the annular opening and recessed from the lower surface; and
a second plurality of gas passages extending axially from the annular zone to the first plurality of gas passages,
wherein the upper plate is configured to couple to a central portion of a lower plate via the annular opening and overlie an upper surface of the lower plate such that the second plurality of gas passages are in fluid communication with a third plurality of gas holes in the lower plate when the upper plate is coupled to the lower plate.

16. The upper plate of claim 15 , wherein a lower plate includes a lower surface having a lower central portion and a lower outer portion; a stepped upper surface having an upper central portion and an upper outer portion, wherein the upper central portion is thicker than the upper outer portion, wherein the upper outer portion includes an annular zone; and a plurality of gas holes located in the annular zone and axially extending between the stepped upper surface and the lower surface; wherein the lower surface includes a lower vacuum sealing surface located on the lower outer portion; and wherein the upper outer portion includes inner and outer upper vacuum sealing surfaces defining the annular zone.

17. The upper plate of claim 15 , wherein the upper plate is made of ceramic material.

18. The upper plate of claim 15 , wherein the first plurality of gas passages include at least 8 radially extending gas passages having diameters of about 0.125 inch and located 45° apart; and the second plurality of gas passages include at least 8 axially extending gas passages having diameters of about 0.125 inch and located about 5.75 inches from a center of the upper plate.

19. The upper plate of claim 15 , wherein the annular zone has a width of about 1.7 inches and depth of about 0.015 to 0.02 inch, the annular zone defining an annular plenum when the upper plate is coupled to a lower plate.

20. An upper plate of a ceramic showerhead assembly useful in an inductively coupled plasma processing apparatus wherein semiconductor substrates supported on a substrate support are subjected to plasma etching, the upper plate comprising:
an upper surface;
a lower surface;
a first plurality of gas passages extending radially and inwardly from an outer periphery of the upper plate;
an annular opening;
an annular zone surrounding the annular opening and recessed from the lower surface;
a second plurality of gas passages extending axially from the annular zone to the first plurality of gas passages; and
inner and outer O-ring grooves surrounding the annular zone.

21. The upper plate of claim 15 , further including 8 pairs of axially extending mounting holes having diameters of about 0.4 inch located in the upper surface of the upper plate; and 8 pairs of radially extending mounting holes havin

Assignees

• Lam Res Corp

Inventors

• Kang Michael
• Paterson Alex
• Kenworthy Ian J

Classifications

• H10P72/0421

  for drying etching · CPC title

• H10P50/244

  comprising alternated and repeated etching and passivation steps · CPC title

• H10P50/642 Primary

  Chemical etching · CPC title

• B05B1/185

  characterised by their outlet element; Mounting arrangements therefor · CPC title

• H10P50/242

  of Group IV materials · CPC title