Apparatus for changing area ratio in a plasma processing system

Patent metadata

Field	Value
Publication number	US-10161042-B2
Application number	US-201213670350-A
Country	US
Kind code	B2
Filing date	Nov 6, 2012
Priority date	Feb 8, 2008
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

A plasma processing system has an upper electrode and a lower electrode. The upper electrode includes a first and a second upper electrode portions. The first upper electrode portion annularly surrounds the second upper electrode portion. The lower electrode includes a first and a second lower electrode portions, and the first lower electrode portion annularly surrounds the second lower electrode portion. A radio frequency (RF) power source provides RF energy to the second lower electrode portion. The lower surface of the first upper electrode portion is non-planar with a substrate-facing surface of the second upper electrode portion such that the first gap between the lower surface of the first upper electrode portion and the upper surface of the first lower electrode portion is smaller than the second gap between the substrate bearing surface of the second lower electrode portion and the substrate-facing surface of the second upper electrode portion.

First claim

What is claimed is:

1. A plasma processing system having a plasma processing chamber for processing a substrate, said plasma processing chamber comprising:
an upper electrode, said upper electrode having a first upper electrode portion and a second upper electrode portion, said first upper electrode portion annularly surrounding said second upper electrode portion;
a lower electrode, said lower electrode having a first lower electrode portion and a second lower electrode portion, said first lower electrode portion annularly surrounding said second lower electrode portion and being disposed opposite the first upper electrode portion, said second lower electrode portion having a substrate bearing surface configured to support said substrate during said processing; and
a radio frequency (RF) power source for providing RF energy to said second lower electrode portion, wherein a lower surface of said first upper electrode portion defines a protrusion that extends toward the first lower electrode portion of the lower electrode and is not co-planar with a substrate-facing surface of said second upper electrode portion such that a first gap between said lower surface of said first upper electrode portion and an upper surface of said first lower electrode portion is smaller than a second gap between said substrate bearing surface of said second lower electrode portion and said substrate-facing surface of said second upper electrode portion, wherein a first angled step at the inner circumference of the first upper electrode portion transitions to a second angled step that transitions onto the protrusion and a gradual transition extending to an outer circumference of the first upper electrode portion to transition off of the protrusion;
wherein the protrusion enables the plasma processing chamber to be operable in two regimes, a first regime involves sustaining of plasma within the second gap and within the first gap, a second regime involves sustaining of plasma within the second gap and a reduction of sustaining of plasma within the first gap.

2. The plasma processing system of claim 1 , wherein both said first upper electrode portion and said second upper electrode portion of said upper electrode are grounded during said processing.

3. The plasma processing system of claim 1 , wherein said first lower electrode portion of said lower electrode is grounded during said processing.

4. The plasma processing system of claim 1 , wherein one of said upper electrode and said lower electrode is movable in a direction that is perpendicular to the substrate bearing surface.

5. The plasma processing system of claim 1 , wherein both said upper electrode and said lower electrode are movable.

6. The plasma processing system of claim 1 , wherein said upper surface of said first lower electrode portion is substantially co-planar with said substrate bearing surface of said second lower electrode portion.

7. The plasma processing system of claim 1 , wherein said upper surface of said first lower electrode portion is not co-planar with said substrate bearing surface of said second lower electrode portion.

8. The plasma processing system of claim 1 , wherein the first regime provides one or both of said upper electrode and said lower electrode to be further apart for the sustaining of plasma within the first gap and within the second gap, the second regime provides one or both of said upper electrode and said lower electrode to be closer together for the sustaining of plasma within the second gap and the reduction of sustaining of plasma within the first gap.

9. The plasma processing system of claim 8 , wherein an area ratio of RF coupling between said upper electrode and said lower electrode is about 1:1 in said second regime.

10. The plasma processing system of claim 1 , wherein the protrusion further includes a flat surface between the second angled step and the gradual transition, wherein the flat surface of the protrusion faces toward the first lower electrode portion.

11. A plasma processing system having a plasma processing chamber for processing a substrate, said plasma processing chamber comprising:
an upper electrode, said upper electrode having a first upper electrode portion and a second upper electrode portion, said first upper electrode portion annularly surrounding said second upper electrode portion, both said first upper electrode portion and said second upper electrode portion being grounded during said processing;
a lower electrode, said lower electrode having a first lower electrode portion and a second lower electrode portion, said first lower electrode portion being grounded and being electrically separated from and annularly surrounding said second lower electrode portion, wherein the first lower electrode portion is disposed opposite said first upper electrode portion, said second lower electrode portion having a substrate bearing surface configured to support said substrate during said processing; and
a radio frequency (RF) power source for providing RF energy to said second lower electrode portion, wherein a lower surface of said first upper electrode portion extends as a protrusion below a substrate-facing surface of said second upper electrode portion such that a first gap between said lower surface of said first upper electrode portion and an upper surface of said first lower electrode portion is smaller than a second gap between said substrate bearing surface of said lower electrode portion and said substrate-facing surface of said second upper electrode portion, wherein a first angled step at an inner circumference of the first upper electrode portion transitions to a second angled step that transitions onto the protrusion of the first upper electrode portion and a gradual transition transitions off of the protrusion and extends to an outer circumference of said first upper electrode portion;
wherein the protrusion enables the plasma processing chamber to be operable in two regimes, a first regime involves sustaining of plasma within the second gap and within the first gap, a second regime involves sustaining of plasma within the second gap and a reduction of sustaining of plasma within the first gap.

12. The plasma processing system of claim 11 , wherein said upper surface of said first lower electrode portion is substantially co-planar with said substrate bearing surface of said second lower electrode portion.

13. The plasma processing system of claim 11 , wherein said upper surface of said first lower electrode portion is not co-planar with said substrate bearing surface of said second lower electrode portion.

14. The plasma processing system of claim 11 , wherein the first regime provides one or both of said upper electrode and said lower electrode to be further apart for the sustaining of plasma within the first gap and within the second gap, the second regime provides one or both of said upper electrode and said lower electrode to be closer together for the sustaining of plasma within the second gap and the reduction of sustaining of plasma within the first gap.

15. The plasma processing system of claim 14 , wherein an area ratio of RF coupling between said upper electrode and said lower electrode is about 1:1 in said second regime.

16. The plasma processing system of claim 11 , wherein said first upper electrode portion of said upper electrode moves with said second upper electrode portion of said upper electrode.

17. The plasma processing system of claim 11 , wherein one of said upper electrode and said lower electrode is movable in a direction that is perpendicular to the substr

Assignees

• Lam Res Corp

Inventors

• Dhindsa Rajinder

Classifications

• H01J37/32091

  the radio frequency energy being capacitively coupled to the plasma · CPC title

• H01J37/32082

  Radio frequency generated discharge (H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence) · CPC title

• H05H2001/466

  Electricity · mapped topic

• H01J37/32816

  Pressure · CPC title

• H01J37/32568 Primary

  Relative arrangement or disposition of electrodes; moving means · CPC title