Methods and apparatus for in-situ cleaning of electrostatic chucks
Methods and apparatus for cleaning an electrostatic chuck (ESC) in a semiconductor chamber allow in-situ cleaning of the ESC. An apparatus may include an adapter or cover ring that is electrically isolated from a deposition ring; an annular grounding bracket mounted to and surrounding a pedestal, the annular grounding bracket has at least one horizontal grounding loop on an upper perimeter surface configured to provide electrical contact with the adapter or cover ring and to provide an RF return path to the ESC during plasma generation; and a bracket with a horizontal grounding loop on a first end to make electrical contact with the deposition ring and a vertical grounding loop on a second end to make electrical contact with a lift hoop which is electrically grounded, the bracket is mounted to, but electrically isolated from, the annular grounding bracket.
1. An apparatus for cleaning an electrostatic chuck (ESC) in a semiconductor chamber, comprising:
a deposition ring surrounding a perimeter of and electrically connected to the ESC;
an adapter or cover ring surrounding and interfacing with an outer perimeter of the deposition ring, the adapter or cover ring is electrically isolated from the deposition ring;
an annular grounding bracket configured to be mounted to and surrounding a pedestal, the annular grounding bracket has at least one horizontal grounding loop on an upper perimeter surface which is configured to provide electrical contact with the adapter or cover ring and to provide an RF (radio frequency) return path to the ESC during plasma generation; and
a bracket with at least one horizontal grounding loop on an upper surface of a first end configured to make electrical contact with the deposition ring and at least one vertical grounding loop on a side surface of a second end that is distal to the first end and configured to make electrical contact with a lift hoop which is electrically grounded, the bracket is configured to be mounted to, but electrically isolated from, the annular grounding bracket.
2. The apparatus of claim 1 , wherein the deposition ring has at least one portion of at least one surface of the deposition ring coated with aluminum deposited by a twin wire arc spray, the at least one portion of at least one surface of the deposition ring configured to contact the at least one horizontal grounding loop of the bracket.
3. The apparatus of claim 2 , wherein the at least one portion of at least one surface of the deposition ring includes a portion of a top surface and a portion of a bottom surface of the deposition ring.
4. The apparatus of claim 1 , wherein the first end of the bracket is configured to be mounted to the annular grounding bracket using at least one insulative spacer.
5. The apparatus of claim 4 , wherein the at least one insulative spacer is a ceramic material.
6. The apparatus of claim 1 , wherein fasteners used to mount the bracket to the annular grounding bracket are surrounded by ceramic sleeves that are configured to maintain electrical isolation between the bracket and the annular grounding bracket.
7. The apparatus of claim 1 , wherein the at least one horizontal grounding loop of the bracket is configured to compress approximately 50% when in contact with the deposition ring.
8. The apparatus of claim 1 , wherein the at least one vertical grounding loop of the bracket is configured to compress approximately 5% to approximately 10% when in contact with the lift hoop.
9. The apparatus of claim 1 , wherein the annular grounding bracket has at least six horizontal grounding loops.
10. The apparatus of claim 1 , wherein the at least one horizontal grounding loop of the bracket is radially inward of the at least one horizontal grounding loop of the annular grounding bracket.
11. The apparatus of claim 1 , wherein the annular grounding bracket is made of stainless steel.
12. An apparatus for cleaning an electrostatic chuck (ESC) when installed in a semiconductor chamber, comprising:
an elongated bracket formed of stainless steel with a horizontal surface at a first end and a vertical surface at a second end distal to the first end, the elongated bracket configured to be mounted in a vertical position when installed in the semiconductor chamber and to be mounted to, but electrically isolated from, an annular grounding bracket at the first end;
at least one first grounding loop electrically connected to the horizontal surface of the first end and configured to make electrical contact by compression when contacting a deposition ring; and
at least one second grounding loop electrically connected to the vertical surface of the second end and configured to make electrical contact by compression when contacting a lift hoop.
13. The apparatus of claim 12 , wherein the first end of the elongated bracket is configured to be mounted to the annular grounding bracket using at least one insulative spacer.
14. The apparatus of claim 13 , wherein the at least one insulative spacer is a ceramic material.
15. The apparatus of claim 12 , wherein the elongated bracket is configured to use fasteners to mount the elongated bracket to the annular grounding bracket that are surrounded by ceramic sleeves that are configured to maintain electrical isolation between the elongated bracket and the annular grounding bracket.
16. The apparatus of claim 12 , wherein the at least one first grounding loop of the elongated bracket is configured to compress approximately 50% when contacting the deposition ring.
17. The apparatus of claim 12 , wherein the at least one second grounding loop of the elongated bracket is configured to compress approximately 5% to approximately 10% when in contact with the lift hoop.
18. The apparatus of claim 12 , wherein the at least one first grounding loop of the elongated bracket is configured to be radially inward of at least one horizontal grounding loop of the annular grounding bracket when installed in the semiconductor chamber.
19. An apparatus for cleaning an electrostatic chuck (ESC) in a semiconductor chamber, comprising:
a deposition ring surrounding a perimeter of and electrically connected to the ESC;
an adapter or cover ring surrounding and interfacing with an outer perimeter of the deposition ring, the adapter or cover ring is electrically isolated from the deposition ring;
an annular grounding bracket is configured to be mounted to and surrounding a pedestal, the annular grounding bracket has at least one horizontal grounding loop on an upper perimeter surface which is configured to provide electrical contact with the adapter or cover ring and to provide an RF (radio frequency) return path to the ESC during plasma generation;
a bracket with at least one horizontal grounding loop on an upper surface of a first end configured to make electrical contact with the deposition ring and at least one vertical grounding loop on a side surface of a second end that is distal to the first end and configured to make electrical contact with a lift hoop which is electrically grounded, the bracket is configured to be mounted to, but electrically isolated from, the annular grounding bracket; and
a controller configured to perform an in-situ cleaning process of the ESC by:
moving the lift hoop to a position that contacts the at least one vertical grounding loop of the bracket to ground the ESC and deposition ring through the bracket;
forming a plasma in the semiconductor chamber with an RF bias applied to the ESC with an RF return path formed by the adapter or cover ring, annular grounding bracket, and the pedestal; and
etching with the plasma a process film buildup from at least a portion of a surface of the deposition ring and at least a portion of a surface of the ESC to perform in-situ cleaning of the ESC and the deposition ring.
20. The apparatus of claim 19 , wherein the deposition ring has at least one portion of at least one surface of the deposition ring coated with aluminum, the at least one portion of at least one surface of the deposition ring configured to contact the at least one horizontal grounding loop of the bracket.