Symmetric plasma process chamber
Embodiments of the present invention provide a plasma chamber design that allows extremely symmetrical electrical, thermal, and gas flow conductance through the chamber. By providing such symmetry, plasma formed within the chamber naturally has improved uniformity across the surface of a substrate disposed in a processing region of the chamber. Further, other chamber additions, such as providing the ability to manipulate the gap between upper and lower electrodes as well as between a gas inlet and a substrate being processed, allows better control of plasma processing and uniformity as compared to conventional systems.
1. A plasma processing apparatus, comprising:
a lid assembly and a chamber body enclosing a processing region; and
a substrate support assembly disposed in the chamber body, wherein the substrate support assembly comprises:
a support pedestal disposed in a central region of the chamber body, the central region fluidly sealed from the processing region;
a lower electrode supported by the support pedestal;
a central support member sealed to the chamber body and the lower electrode;
a plasma screen supported by the lower electrode and extending along a periphery of the substrate support assembly;
an upper liner having an inner wall that overlaps a portion of the plasma screen;
a plurality of lift pins disposed in the substrate support assembly; and
an actuation device disposed within the central region and configured to vertically move the plurality of lift pins, wherein the plurality of lift pins are coupled to a lift pin plate;
a plurality of access tubes positioned symmetrically through the chamber body and below the central support member to provide access to the central region, wherein each access tube is vertically spaced a distance from the processing region;
a plurality of evacuation passages positioned in the bottom wall of the upper liner and symmetrically disposed about the central axis of the substrate support assembly; and
a plurality of evacuation channels symmetrically disposed in the chamber body, each evacuation channel of the plurality of evacuation channels extends between two of the plurality of access tubes and each evacuation channel of the plurality of evacuation channels extends below a corresponding one of the plurality of evacuation passages.
2. The plasma processing apparatus of claim 1 , further comprising a vent line fluidly coupled to one or more lift pin holes disposed within the lower electrode.
3. The plasma processing apparatus of claim 2 , further comprising a gas supply line fluidly coupled to a gas port disposed in the lower electrode.
4. The plasma processing apparatus of claim 2 , wherein the vent line is fluidly coupled to an exhaust region of the chamber body.
5. The plasma processing apparatus of claim 1 , wherein the lid assembly comprises:
an upper electrode having one or more fluid inlets and one or more fluid outlets each having conductive fittings; and
a plurality of conductive plugs, wherein the conductive fittings and conductive plugs are arranged symmetrically about a central axis of the substrate support assembly.
6. The plasma processing apparatus of claim 1 , wherein the lid assembly comprises:
an upper electrode having a central manifold configured to distribute processing gas into the processing region and one or more outer manifolds configured to distribute processing gas into the processing region; and
a ring manifold coupled to the one or more outer manifolds via a plurality of gas tubes arranged symmetrically about a central axis of the substrate support assembly.
7. The plasma processing apparatus of claim 1 , wherein the actuation device comprises;
a lead screw coupled to the lift pin plate; and
an actuator configured to advance and retract the lead screw.
8. The plasma processing apparatus of claim 7 , wherein the lead screw extends within the support pedestal.
9. The plasma processing apparatus of claim 1 , wherein the lift pin plate is disposed within an opening within the lower electrode.
10. A substrate support assembly for a plasma processing apparatus, comprising:
a support pedestal;
a lower electrode coupled to and supported by the support pedestal;
a central support member sealed to a chamber body and the lower electrode, wherein a plurality of access tubes are positioned symmetrically through the chamber body and below the central support member to provide access to the central region, wherein each access tube is vertically spaced a distance from the processing region;
a plasma screen supported by the lower electrode and extending along a periphery of the substrate support assembly, the plasma screen overlaps a portion of an upper liner:
a plurality of lift pins coupled to a lift pin plate;
a plurality of evacuation passages positioned in the bottom wall of the upper liner and symmetrically disposed about a central axis of the substrate support assembly; and
a plurality of evacuation channels symmetrically disposed in the chamber body, each evacuation channel of the plurality of evacuation channels extends between two of the plurality of access tubes and each evacuation channel of the plurality of evacuation channels extends below a corresponding one of the plurality of evacuation passages.
11. The substrate support assembly of claim 10 , further comprising an actuation device coupled to the lift pin plate and configured to vertically move the plurality of lift pins.
12. The substrate support assembly of claim 11 , wherein the actuation device comprises;
a lead screw coupled to the lift pin plate; and
an actuator configured to advance and retract the lead screw.
13. The substrate support assembly of claim 12 , where the lead screw extends within the support pedestal.
14. The substrate support assembly of claim 10 , wherein the lift pin plate is disposed within an opening within the lower electrode.
15. A plasma processing apparatus, comprising:
a lid assembly and a chamber body enclosing a processing region;
a substrate support assembly disposed in the chamber body, wherein the substrate support assembly comprises:
a support pedestal disposed in a central region of the chamber body, the central region fluidly sealed from the processing region; and
a lower electrode supported by the support pedestal;
a central support member sealed to the chamber body and the lower electrode, wherein a plurality of access tubes are positioned symmetrically through the chamber body and below the central support to provide access to the central region, wherein each access tube is vertically spaced a distance from the processing region; and
a plasma screen supported by the lower electrode and extending along a periphery of the substrate support assembly;
an upper liner having an inner wall that overlaps a portion of the plasma screen, wherein a plurality of evacuation passages are positioned in a bottom wall of the upper liner and symmetrically disposed about the central axis of the substrate support assembly; and
an exhaust assembly defining an evacuation region within the chamber body, wherein the chamber body includes a plurality of evacuation channels symmetrically disposed about a central axis of the substrate support assembly fluidly connecting the processing region with the evacuation region,
wherein each evacuation channel of the plurality of evacuation channels extends between two of the plurality of access tubes, each evacuation channel of the plurality of evacuation channels extending below a corresponding one of the plurality of evacuation passages.
16. The plasma processing apparatus of claim 15 , wherein the chamber body has an exhaust port formed therethrough that is symmetric about the central axis of the substrate support assembly.
17. The plasma processing apparatus of claim 15 , further comprising an actuation device coupled to a lift pin plate and configured to vertically move a plurality of lift pins.
18. The plasma processing apparatus of claim 17 , wherein the actuation device comprises;
a lead screw coupled to the lift pin plate; and
an actuator configured to advance and retract the lead screw.
19. The plasma processing apparatus of claim 18 , wherein the lead screw extends within the support pedestal.
20. The plasma processing apparatus of claim 17 , wherein the lift pin plate is disposed to be within an opening within the lower electrode.