Passive compensation for temperature-dependent wafer gap changes in plasma processing systems

Abstract

Passive wafer gap compensation arrangements and methods relying on temperature-driven dimensional change of thermally expanding component(s) to counteract, substantially or partially, the change in the wafer gap due to chamber component temperature change is provided. The passive arrangements and techniques involve passively raising or lowering the substrate-facing component or the substrate support to counteract, substantially or partially, the gap-narrowing effect or gap-expanding effect of rising temperature, thereby reducing or eliminating the change in the wafer gap due to a change in the chamber component temperature. Cooling arrangement(s) and thermal break(s) are optionally provided to improve performance.

1 . A plasma processing system for processing a substrate, said plasma processing system having at least a chamber, said chamber having at least a substrate support and a substrate-facing component that faces an upper surface of said substrate in a spaced-apart relationship above said substrate, said substrate disposed on top of said substrate support and between said substrate support and said substrate-facing component during said processing, comprising:
 substrate-facing component support structure coupled between said substrate-facing component and an upper chamber component of said plasma processing chamber to position said substrate-facing component above said substrate during said processing such that a desired gap exists between a lower surface of said substrate-facing component and an upper surface of said substrate; and   means for passively moving said substrate-facing component responsive to temperature change experienced by at least one component of said plasma processing chamber, said temperature change experienced by said at least one component causing said desired gap to change if said substrate-facing component is not passively moved, said means for passively moving said substrate-facing component relying on thermally-driven dimensional change of said means to accomplish said moving.   
     
     
         2 . The plasma processing system of  claim 1  wherein said substrate-facing component is an upper insulator plate and where in said chamber is a bevel etch chamber. 
     
     
         3 . The plasma processing system of  claim 1  wherein said substrate-facing component is an upper electrode. 
     
     
         4 . The plasma processing system of  claim 1  wherein said substrate support is a lower electrode. 
     
     
         5 . The plasma processing system of  claim 1  wherein said change represents a narrowing of said desired gap when said at least one component experiences an increase in temperature, said means for passively moving configured to raise said substrate-facing component responsive to said narrowing. 
     
     
         6 . The plasma processing system of  claim 1  wherein said change represents an expansion of said desired gap when said at least one component experiences an increase in temperature, said means for passively moving configured to lower said substrate-facing component responsive to said expansion. 
     
     
         7 . The plasma processing system of  claim 1  wherein said passively moving includes passively moving said upper chamber component. 
     
     
         8 . The plasma processing system of  claim 1  wherein said upper chamber component includes an attachment site for attaching said substrate-facing component support structure. 
     
     
         9 . The plasma processing system of  claim 1  wherein said means for passively moving includes at least one thermal break. 
     
     
         10 . The plasma processing system of  claim 1  wherein said means for passively moving includes at least one thermally expanding component. 
     
     
         11 . The plasma processing system of  claim 1  wherein said means for passively moving includes a plurality of thermally expanding components configured for symmetrically moving said substrate-facing component responsive to temperature change. 
     
     
         12 . The plasma processing system of  claim 1  wherein said means for passively moving is configured to substantially cancel out an amount by which said desired gap would have been changed in the absence of said means for passively moving if a temperature of said at least one component is increased. 
     
     
         13 . The plasma processing system of claim A 1  wherein said means for passively moving includes a cooling subsystem. 
     
     
         14 . A plasma processing system for processing a substrate, said plasma processing system having at least a chamber, said chamber having at least a substrate support and a substrate-facing component that faces an upper surface of said substrate in a spaced-apart relationship above said substrate, said substrate disposed on top of said substrate support and between said substrate support and said substrate-facing component during said processing, comprising:
 substrate-facing component support structure coupled between said substrate-facing component and an upper chamber component of said plasma processing chamber to position said substrate-facing component above said substrate during said processing such that a desired gap exists between a lower surface of said substrate-facing component and an upper surface of said substrate; and   means for passively moving said substrate support responsive to temperature change experienced by at least one component of said plasma processing chamber, said temperature change experienced by said at least one component causing said desired gap to change if said substrate support is not passively moved, said means for passively moving said substrates support relying on thermally-driven dimensional change of said means to accomplish said moving.   
     
     
         15 . The plasma processing system of  claim 14  wherein said substrate-facing component is an upper insulator plate and where in said chamber is a bevel etch chamber. 
     
     
         16 . The plasma processing system of  claim 14  wherein said substrate-facing component is an upper electrode. 
     
     
         17 . The plasma processing system of  claim 14  wherein said substrate support is a lower electrode. 
     
     
         18 . The plasma processing system of  claim 14  wherein said change represents a narrowing of said desired gap when said at least one component experiences an increase in temperature, said means for passively moving configured to lower said substrate support responsive to said narrowing. 
     
     
         19 . The plasma processing system of  claim 14  wherein said change represents an expansion of said desired gap when said at least one component experiences an increase in temperature, said means for passively moving configured to raise said substrate support responsive to said expansion. 
     
     
         20 . The plasma processing system of  claim 14  wherein said means for passively moving includes at least one thermal break. 
     
     
         21 . The plasma processing system of  claim 14  wherein said means for passively moving includes at least one thermally expanding component. 
     
     
         22 . The plasma processing system of  claim 14  wherein said means for passively moving includes a plurality of thermally expanding components configured for symmetrically moving said substrate support responsive to temperature change. 
     
     
         23 . The plasma processing system of  claim 14  wherein said means for passively moving is configured to substantially cancel out an amount by which said desired gap would have been changed in the absence of said means for passively moving if a temperature of said at least one component is increased. 
     
     
         24 . The plasma processing system of  claim 14  wherein said means for passively moving includes a cooling subsystem.