Circuits for edge ring control in shaped dc pulsed plasma process device
The present disclosure relates to an apparatus and method that manipulate the voltage at an edge ring relative to a substrate located on a substrate support assembly. The substrate support assembly has a body having a substrate support portion having a substrate electrode embedded therein for applying a substrate voltage to a substrate. The body of the substrate support assembly further has an edge ring portion disposed adjacent to the substrate support portion. The edge ring portion has an edge ring electrode embedded therein for applying an edge ring voltage to an edge ring. An edge ring voltage control circuit is coupled to the edge ring electrode. A substrate voltage control circuit is coupled to the substrate electrode. The edge ring voltage control circuit and the substrate voltage control circuit are independently tunable to generate a difference in voltage between the edge ring voltage and the substrate voltage.
1. A substrate support assembly comprising:
an electrostatic chuck (ESC) having a ceramic body, the ceramic body having a center and an outer perimeter, the ceramic body comprising:
a substrate support portion disposed at the center and having a substrate electrode embedded in the ceramic body of the ESC for applying a substrate voltage to a substrate; and
an edge ring portion adjacent the outer perimeter and circumscribing the substrate support portion, the edge ring portion having an edge ring electrode embedded in ceramic body of the ESC for applying an edge ring voltage to an edge ring;
an edge ring voltage control circuit coupled to the edge ring electrode disposed in the ceramic body, wherein the edge ring voltage control circuit further comprises:
a first fixed resistor coupled in series with a first fixed capacitor; and
a second variable capacitor coupled in parallel with the first fixed resistor and first capacitor, wherein a first common terminal between the second variable capacitor and the first fixed resistor is coupled to at least one shaped DC pulse voltage source and wherein a second common terminal between the second variable capacitor and the first fixed capacitor is coupled to the edge ring electrode; and
a substrate voltage control circuit coupled to the substrate electrode, wherein the edge ring voltage control circuit and substrate voltage control circuit are independently tunable to supply a different direct current voltage to the edge ring electrode and the substrate electrode.
2. The substrate support assembly of claim 1 , wherein the edge ring portion and the substrate support portion of the ceramic body of the ESC are formed of a single piece of ceramic material.
3. The substrate support assembly of claim 2 , wherein the body is an electrostatic chuck.
4. The substrate support assembly of claim 2 , wherein the edge ring voltage control circuit and the substrate voltage control circuit are identical circuits.
5. The substrate support assembly of claim 2 , wherein the edge ring voltage control circuit and the substrate voltage control circuit differ from each other.
6. The substrate support assembly of claim 2 , further comprising:
a first shaped DC pulse voltage source coupled in parallel to both the edge ring voltage control circuit and the substrate voltage control circuit.
7. The substrate support assembly of claim 2 , further comprising:
a first shaped DC pulse voltage source coupled to the edge ring voltage control circuit and
a second shaped DC pulse voltage source coupled to the substrate voltage control circuit.
8. The substrate support assembly of claim 2 , further comprising:
a cooling base disposed in contact with the body; and
a facility plate disposed below a cooling plate.
9. The substrate support assembly of claim 8 , wherein the cooling plate is in contact with both the edge ring portion and the substrate support portion of the body.
10. The substrate support assembly of claim 8 , wherein the facility plate is electrically insulated from the cooling base.
11. The substrate support assembly of claim 1 , further comprising:
a third capacitor coupled between the at least one shaped DC pulse voltage source and the substrate electrode.
12. The substrate support assembly of claim 1 , further comprising:
a second resistor coupled in series with the first fixed resistor.
13. A process chamber comprising:
a chamber body;
a lid disposed on the chamber body;
a capacitively coupled plasma apparatus; and
a substrate support assembly positioned within the chamber body, the substrate support assembly having an electrostatic chuck (ESC), the ESC having a ceramic body, the ceramic body having a center and a outer perimeter, the ceramic body comprising:
a substrate support portion disposed at the center and having a substrate electrode embedded in ceramic body of the ESC for applying a substrate voltage to a substrate; and
an edge ring portion adjacent the outer perimeter and circumscribing the substrate support portion, the edge ring portion having an edge ring electrode embedded in ceramic body of the ESC for applying an edge ring voltage to an edge ring, wherein the edge ring portion and the substrate support portion of the ceramic body of the ESC are formed of a single piece of ceramic material;
an edge ring voltage control circuit coupled to the edge ring electrode disposed in the ceramic body, wherein the edge ring voltage control circuit further comprises:
a first fixed resistor coupled in series with a first fixed capacitor; and
a second variable capacitor coupled in parallel with the first fixed resistor and first capacitor, wherein a first common terminal between the second variable capacitor and the first fixed resistor is coupled to at least one shaped DC pulse voltage source and wherein a second common terminal between the second variable capacitor and the first fixed capacitor is coupled to the edge ring electrode; and
a substrate voltage control circuit coupled to the substrate electrode, wherein the edge ring voltage control circuit and substrate voltage control circuit are independently tunable to supply a different direct current voltage to the edge ring electrode and the substrate electrode.
14. The process chamber of claim 13 , further comprising:
a first shaped DC pulse voltage source coupled in parallel to both the edge ring voltage control circuit and the substrate voltage control circuit.
15. The process chamber of claim 13 , further comprising:
a first shaped DC pulse voltage source coupled to the edge ring voltage control circuit and
a second shaped DC pulse voltage source coupled to the substrate voltage control circuit.
16. The process chamber of claim 13 , further comprising:
a third capacitor coupled between at least one shaped DC pulse voltage source and the the substrate electrode; and
an inductor coupled in series with the first capacitor.