Systems and methods for controlling directionality of ions in an edge region by using an electrode within a coupling ring

Patent metadata

Field	Value
Publication number	US-10115568-B2
Application number	US-201715825021-A
Country	US
Kind code	B2
Filing date	Nov 28, 2017
Priority date	Jun 22, 2016
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

Systems and methods for controlling directionality of ion flux at an edge region within a plasma chamber are described. One of the systems includes a radio frequency (RF) generator that is configured to generate an RF signal, an impedance matching circuit coupled to the RF generator for receiving the RF signal to generate a modified RF signal, and a plasma chamber. The plasma chamber includes an edge ring and a coupling ring located below the edge ring and coupled to the first impedance matching circuit to receive the modified RF signal. The coupling ring includes an electrode that generates a capacitance between the electrode and the edge ring to control the directionality of the ion flux upon receiving the modified RF signal.

First claim

The invention claimed is:

1. A coupling ring comprising:
an insulator material having an annular shape, wherein the insulator material has a top surface, a bottom surface, and an inner side surface;
an electrode embedded within the insulator material, wherein the electrode is located at a first distance below the top surface of the insulator material and at a second distance above the bottom surface of the insulator material; and
a through path formed into the insulator material to extend from the bottom surface of the insulator material to an undersurface of the electrode, wherein the through path is configured to receive a power pin for electrically coupling to the undersurface of the electrode;
wherein the coupling ring is configured to be placed within a plasma chamber in an orientation that has the inner side surface surrounding a portion of a chuck of the plasma chamber.

2. The coupling ring of claim 1 , wherein a portion of the insulator material located between the electrode and the top surface of the insulator material acts as a dielectric to facilitate capacitive coupling between the electrode and an edge ring of the plasma chamber.

3. The coupling ring of claim 1 , wherein the first distance is less than the second distance.

4. The coupling ring of claim 1 , wherein the electrode is a mesh electrode having a plurality of crossings of wires to form a net-like structure.

5. The coupling ring of claim 1 , wherein the electrode is a ring-shaped electrode that is flat.

6. The coupling ring of claim 1 , wherein the power pin includes a coaxial cable and a sleeve surrounding the coaxial cable.

7. The coupling ring of claim 1 , wherein a portion of the insulator material located between the electrode and the top surface of the insulator material acts as a dielectric to facilitate capacitive coupling between the electrode and an edge ring of the plasma chamber, wherein the power pin is coupled via a feed ring to an RF transmission line for receiving an RF signal to facilitate the capacitive coupling, wherein the feed ring has a circular portion and a plurality of arms, wherein one of the arms is coupled to an RF rod of the RF transmission line for receiving the RF signal from the RF rod, wherein another one of the arms is coupled to the power pin for providing the RF signal to a location on the electrode.

8. The coupling ring of claim 1 , wherein the top surface of the insulator material is configured to be located adjacent to a bottom surface of an edge ring of the plasma chamber and a portion of the bottom surface of the insulator material is configured to be located adjacent to a surface of an insulator ring of the plasma chamber, wherein the edge ring faces an upper electrode of the plasma chamber to form a gap between the upper electrode and the edge ring.

9. The coupling ring of claim 1 ,
wherein the power pin is coupled to an impedance matching circuit via a radio frequency (RF) transmission line for receiving a modified RF signal from the impedance matching circuit via the RF transmission line, wherein the impedance matching circuit is coupled to an RF generator for receiving an RF signal from the RF generator.

10. The coupling ring of claim 9 , wherein the power pin is coupled to the impedance matching circuit via an RF filter, wherein the RF filter is configured to filter a direct current (DC) signal to protect an edge ring of the plasma chamber from the DC signal, wherein the top surface of the insulator material is adjacent to the edge ring.

11. The coupling ring of claim 1 , wherein a portion of the insulator material separates the power pin from the chuck of the plasma chamber.

12. The coupling ring of claim 1 ,
wherein the power pin is coupled to a radio frequency (RF) filter via an RF transmission line for receiving a filtered RF signal from the RF filter via the RF transmission line, wherein the RF filter is coupled to a ground potential.

13. The coupling ring of claim 12 , wherein the power pin is coupled to the RF filter via an additional RF filter, wherein the additional RF filter is configured to filter a direct current (DC) signal to protect an edge ring of the plasma chamber from the DC signal, wherein the top surface of the insulator material is adjacent to the edge ring.

14. A coupling ring comprising:
a body having an annular shape, a top surface, a bottom surface, an inner side surface; and an outer side surface;
an electrode embedded within the body, wherein the electrode is located at a first distance below the top surface of the body and at a second distance above the bottom surface of the body; and
an opening in the body extending from the bottom surface to an undersurface of the electrode, wherein the opening is configured to receive a connection for electrically coupling to the undersurface of the electrode;
wherein the inner side surface of the body is configured to surround a portion of a chuck in a plasma chamber.

15. The coupling ring of claim 14 , wherein a portion of the body between the electrode and the top surface of the body acts as a dielectric to facilitate capacitive coupling between the electrode and an edge ring of the plasma chamber.

16. The coupling ring of claim 14 , wherein the first distance is less than the second distance.

17. The coupling ring of claim 14 , wherein the electrode is a mesh electrode having a plurality of crossings of wires to form a net-like structure.

18. The coupling ring of claim 14 , wherein the electrode is a ring-shaped electrode that is flat.

19. The coupling ring of claim 14 , wherein the connection is a power pin including a coaxial cable and a sleeve surrounding the coaxial cable.

20. The coupling ring of claim 14 , wherein the top surface of the body is configured to be located adjacent to a bottom surface of an edge ring of the plasma chamber and a portion of the bottom surface of the body is configured to be located adjacent to a surface of an insulator ring of the plasma chamber, wherein the edge ring faces an upper electrode of the plasma chamber to form a gap between the upper electrode and the edge ring.

21. The coupling ring of claim 14 ,
wherein the connection is coupled to an impedance matching circuit via a radio frequency (RF) transmission line for receiving a modified RF signal from the impedance matching circuit via the RF transmission line, wherein the impedance matching circuit is coupled to an RF generator for receiving an RF signal from the RF generator.

22. The coupling ring of claim 14 , wherein a portion of the body separates the connection from the chuck of the plasma chamber.

23. The coupling ring of claim 22 , wherein the connection is coupled to the impedance matching circuit via an RF filter, wherein the RF filter is configured to filter a direct current (DC) signal to protect an edge ring of the plasma chamber from the DC signal, wherein the top surface of the body is adjacent to the edge ring.

24. The coupling ring of claim 14 ,
wherein the connection is coupled to a radio frequency (RF) filter via an RF transmission line for receiving a filtered RF signal from the RF filter via the RF transmission line, wherein the RF filter is coupled to a ground potential.

25. The coupling ring of claim 24 , wherein the connection is coupled to the RF filter via an additional RF filter, wherein the additional RF filter is configured to filter a direct current (DC) signal to protect an edge ring of the plasma chamber

Assignees

• Lam Res Corp

Inventors

• Kellogg Michael C
• Marakhtanov Alexei
• Holland John Patrick
• Chen Zhigang
• Kozakevich Felix
• Lucchesi Kenneth

Classifications

• H01J37/32091

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

• H01J37/32155 Primary

  Frequency modulation · CPC title

• H01J37/32642 Primary

  Focus rings · CPC title

• H01J37/32715

  Workpiece holder · CPC title

• H01J37/32623

  Mechanical discharge control means · CPC title