Symmetrical Inductively Coupled Plasma Source with Symmetrical Flow Chamber

Abstract

A plasma reactor has an overhead multiple coil inductive plasma source with symmetric RF feeds and a symmetrical chamber exhaust with plural struts through the exhaust region providing access to a confined workpiece support. A grid may be included for masking spatial effects of the struts from the processing region.

1 - 20 . (canceled) 
     
     
         21 . A plasma reactor comprising:
 an axially symmetric side wall, a lid assembly overlying the side wall, and a workpiece support having a workpiece support surface, wherein the side wall, lid assembly and workpiece support define a processing region;   at least one coil antenna coaxial with the side wall;   an exhaust chamber wall defining an evacuation region below the processing region;   a chamber body defining a central space, the chamber body including a chamber body wall that extends downward from the workpiece support and is surrounded by the exhaust chamber wall, the central space positioned below the workpiece support and surrounded by the evacuation region and sealed from the processing region and from the evacuation region by the chamber body;   a plurality of struts extending from the chamber body wall through the evacuation region to the exhaust chamber wall;   a gas flow grid having a top surface positioned below the workpiece support surface and a bottom surface positioned above the plurality of struts, the gas flow grid including plural exhaust passages extending in an axial direction through the gas flow grid to couple the processing region to the evacuation region; and   a vacuum pump port coupled to the evacuation region and centered relative to the side wall.   
     
     
         22 . The plasma reactor of  claim 21 , wherein the workpiece support comprises a pedestal having a support post. 
     
     
         23 . The plasma reactor of  claim 22 , wherein the support post extends into the central space. 
     
     
         24 . The plasma reactor of  claim 22 , further comprising a lift mechanism secured to the chamber body and configured to move the pedestal in an axial direction. 
     
     
         25 . The plasma reactor of  claim 21 , wherein the plurality of struts are hollow access struts and the plasma reactor comprises respective utility lines extending through respective ones of said hollow access struts. 
     
     
         26 . The plasma reactor of  claim 21 , wherein the struts are distributed symmetrically with respect to the axis of symmetry. 
     
     
         27 . The plasma reactor of  claim 21 , comprising a chamber body liner coupling an outer edge of the gas flow grid to the exhaust chamber wall, the chamber body liner including a vertically extending cylindrical section. 
     
     
         28 . The plasma reactor of  claim 27 , wherein the vertically extending cylindrical section is spaced apart from the exhaust chamber wall such that a portion of the evacuation volume surrounds the processing region. 
     
     
         29 . The plasma reactor of  claim 27 , wherein the vertically extending cylindrical section extends from a lower edge to an upper edge that is above the workpiece support surface. 
     
     
         30 . The plasma reactor of  claim 27 , wherein the gas flow grid and chamber liner are metal. 
     
     
         31 . The plasma reactor of  claim 21 , wherein the gas flow grid comprises an annular array of elongate openings each extending in a radial direction. 
     
     
         32 . The plasma reactor of  claim 31 , wherein the elongate openings are uniformly spaced around the axis of symmetry. 
     
     
         33 . The plasma reactor of  claim 31 , wherein at least some of the elongate openings are positioned laterally over the struts. 
     
     
         34 . The plasma reactor of  claim 21 , wherein the gas flow grid forms an inverted truncated cone. 
     
     
         35 . The plasma reactor of  claim 21 , wherein the evacuation region extends below a floor of the chamber body.