Plasma source with symmetrical rf feed

Abstract

A plasma reactor includes inner, middle and outer current distributors to carry RF power to be supplied to a plasma in the processing region, and a plurality of RF power feeds connected between a plurality of RF power terminals and the inner, middle and outer current distributors. The current distributors are successive concentric axially symmetric hollow bodies. The plurality of current feeds include a middle RF power feed that includes an axial upper portion connected to one of the plurality of RF power terminals, a plurality of arms extending radially outwardly from the axial upper portion, and a plurality of axially extending RF connection rods extending from outer ends of the plurality of arms to the middle current distributor.

1 - 20 . (canceled) 
     
     
         21 . A plasma reactor comprising:
 a chamber enclosing a processing region, the chamber having a ceiling;   a workpiece support to hold the workpiece in the chamber;   inner, middle and outer current distributors to carry RF power to be supplied to a plasma in the processing region, wherein the inner, middle and outer current distributors each comprise an axially symmetric hollow body with the outer current distributor surrounding and concentric with the middle current distributor and the middle current distributor surrounding and concentric with the inner current distributor; and   a plurality of RF power feeds connected between a plurality of RF power terminals and the inner, middle and outer current distributors, wherein the plurality of current feeds includes a middle RF power feed that includes an axial upper portion connected to one of the plurality of RF power terminals, a plurality of arms extending radially outwardly from the axial upper portion, and a plurality of axially extending RF connection rods extending from outer ends of the plurality of arms to the middle current distributor.   
     
     
         22 . The plasma reactor of claim  1 , wherein each axially symmetric hollow body is a cylinder. 
     
     
         23 . The plasma reactor of claim  1 , wherein the upper axial portion comprises an axial rod. 
     
     
         24 . The plasma reactor of claim  3 , wherein the plurality of axially extending RF connection rods extend through apertures in one or more conductive plates. 
     
     
         25 . The plasma reactor of claim  1 , wherein the plurality of current feeds includes an axially extending inner RF power feed. 
     
     
         26 . The plasma reactor of claim  5 , wherein the inner RF power feed comprises an axially extending cylindrical body. 
     
     
         27 . The plasma reactor of claim  1 , wherein the plurality of current feeds includes a radially extending outer RF power feed. 
     
     
         28 . The plasma reactor of claim  7 , wherein the radially extending outer RF power feed comprises a radially extending skirt. 
     
     
         29 . The plasma reactor of claim  1 , wherein inner ends of the plurality of arms that are connected to the axial upper portion to the middle current distributor are positioned radially inward of the middle current distributor. 
     
     
         30 . The plasma reactor of claim  1 , comprising a bottom electrode embedded in the workpiece support.