Apparatus for plasma processing system with tunable capacitance

Abstract

A plasma processing system having a plasma processing chamber configured for processing a substrate is provided. The substrate is disposed above a chuck and surrounded by an edge ring, which is electrically isolated from the chuck. The system includes a RF power, which provides power to the chuck. The system also includes a tunable capacitance arrangement, which is coupled to the edge ring to provide RF coupling to the edge ring, resulting in the edge ring having an edge ring potential. The system further includes the plasma processing chamber configured to strike plasma to process the substrate, which is processed while the tunable capacitance arrangement is configured to cause the edge ring potential to be dynamically tunable to a DC potential of the substrate while processing the substrate.

1 - 20 . (canceled) 
     
     
         21 . A plasma processing system having a plasma processing chamber configured for processing a substrate, said substrate being disposed above a chuck and surrounded by an edge ring, said edge ring being electrically isolated from said chuck, comprising:
 RF power is provided to said chuck;   a tunable capacitance arrangement, said tunable capacitance arrangement being coupled to said edge ring to provide RF coupling to said edge ring, resulting in said edge ring having an edge ring potential; and   said plasma processing chamber is configured to strike plasma to process said substrate, said substrate being processed while said tunable capacitance arrangement is configured to cause said edge ring potential to be dynamically tunable to a DC potential of said substrate while processing said substrate.   
     
     
         22 . The plasma processing system of  claim 21 , wherein said tunable capacitance arrangement includes a coupling ring assembly. 
     
     
         23 . The plasma processing system of  claim 22 , wherein said coupling ring assembly comprising:
 an upper coupling ring;   a lower coupling ring, said lower coupling ring is coupled with said upper coupling ring to form a hermetic seal; and   a hermetically sealed cavity, said hermetically sealed cavity being disposed inside said coupling ring assembly, wherein said hermetically sealed cavity is configured with an inlet and an outlet to transport dielectric material into or out of said hermetically sealed cavity to change the capacitance of said coupling assembly.   
     
     
         24 . The plasma processing system of  claim 23 , wherein said dielectric material includes at least one of a solid, a liquid, and a gas. 
     
     
         25 . The plasma processing system of  claim 24 , wherein said dielectric material includes at least one of air, nitrogen, mineral oil, castor oil, water, and glycerol. 
     
     
         26 . The plasma processing system of  claim 23 , wherein said transport of said predetermined dielectric material is achieved by at least one of an active flow control system and a passive flow control system. 
     
     
         27 . The plasma processing system of  claim 21 , wherein said tunable capacitance arrangement is a mechanical switch. 
     
     
         28 . The plasma processing system of  claim 27 , wherein said mechanical switch comprises:
 a shaft;   a contact foot; and   a moveable connector, said moveable connector being disposed above said shaft, said shaft is configured facilitate moving said moveable connector up or down relative to said contact foot, said contact foot is configured to couple to said edge ring.   
     
     
         29 . The plasma processing system of  claim 28 , wherein said shall is RF coupled to said chuck by a strap. 
     
     
         30 . The plasma processing system of  claim 28 , wherein said edge ring is configured to achieve maximum RF coupling if said moveable connector physically contacts with said contact foot. 
     
     
         31 . The plasma processing system of  claim 28 , wherein said edge ring is configured to achieve minimum RF coupling if said moveable connector does not physically contact with said contact foot enabling bevel edge cleaning of said substrate. 
     
     
         32 . The plasma processing system of  claim 21 , wherein said tunable capacitance arrangement is a mechanical capacitor arrangement. 
     
     
         33 . The plasma processing system of  claim 32 , wherein said mechanical capacitor arrangement comprising:
 a first plate;   a second plate, said second plate is configured to be parallel with said first plate, said first plate is configured to protrude downward from said edge ring, said first plate and said second plate are separated by an air gap;   a plurality of straps, said plurality of straps are configured to RF couple said second plate to said chuck; and   means to move said second plate up or down to adjust an overlapping area with said first plate during plasma processing.   
     
     
         34 . The plasma processing system of  claim 32 , wherein said mechanical capacitor arrangement comprising:
 a first concentric ring, said first concentric ring is configured with a first plurality of cutouts;   a second concentric ring, said second concentric ring is configured with a second plurality of cutouts, said second concentric ring is configured to be parallel with said first concentric ring, said first concentric ring and second concentric ring are separated by an air gap; and   means to rotate said second concentric ring to adjust an overlapping area with said first concentric ring during plasma processing.   
     
     
         35 . The plasma processing system of  claim 33 , wherein said second plate being movable such that said overlapping area with said first plate is maximized to minimized potential difference between said substrate and said edge ring to attain uniform etching of said substrate. 
     
     
         36 . The plasma processing system of  claim 33 , wherein said second plate being movable such that said overlapping area with said first plate is minimized to maximize potential difference between said substrate and said edge ring to enable bevel edge cleaning of said substrate. 
     
     
         37 . The plasma processing system of  claim 34 , wherein said second concentric ring being movable such that said overlapping area with said first concentric ring is maximized to minimized potential difference between said substrate and said edge ring to attain uniform etching of said substrate. 
     
     
         38 . The plasma processing system of  claim 34 , wherein said second concentric ring being movable such that said overlapping area with said first concentric ring is minimized to maximize potential difference between said substrate and said edge ring to enable bevel edge cleaning of said substrate. 
     
     
         39 . The plasma processing system of  claim 23 , wherein said capacitance of said coupling assembly being adjusted by said dielectric material to minimize electrical potential difference between said substrate and said edge ring to attain uniform etching of said substrate. 
     
     
         40 . The plasma processing system of  claim 23 , wherein said capacitance of said coupling assembly being adjusted by said dielectric material to maximize electrical potential difference between said substrate and said edge ring to enable bevel edge cleaning of said substrate.