Anti-arc zero field plate

Abstract

Embodiments of the present invention generally relate to apparatus for reducing arcing and parasitic plasma in substrate processing chambers. The apparatus generally include a processing chamber having a substrate support, a backing plate, and a showerhead disposed therein. A showerhead suspension electrically couples the backing plate to the showerhead. An electrically conductive bracket is coupled to the backing plate and spaced apart from the showerhead. The electrically conductive bracket may include a plate, a lower portion, an upper portion, and a vertical extension. The electrically conductive bracket contacts an electrical isolator.

We claim: 
     
         1 . A vacuum processing chamber, comprising:
 a backing plate disposed in a chamber body;   a showerhead disposed in the chamber body and coupled to the backing plate;   one or more showerhead suspensions electrically coupling the backing plate to the showerhead;   an electrically conductive bracket coupled to the backing plate and spaced apart from the showerhead suspension, the electrically conductive bracket comprising:
 a plate positioned substantially perpendicular to a face of the showerhead; 
 a lower portion coupled to a bottom edge of the plate, the lower portion substantially perpendicular to the plate; and 
 a vertical extension coupled to the lower portion, the vertical extension parallel to the plate, wherein the vertical extension has a length less than a length of the plate; and 
   an electrical isolator having a first side contacting the plate of the electrically conductive bracket and a second side contacting the chamber body.   
     
     
         2 . The processing chamber of  claim 1 , wherein the processing chamber is a PECVD chamber, and the PECVD chamber further comprises an RF source coupled to the backing plate. 
     
     
         3 . The processing chamber of  claim 1 , wherein the electrical isolator comprises ceramic, alumina, or polytetrafluoroethylene. 
     
     
         4 . The processing chamber of  claim 1 , wherein the electrically conductive bracket comprises aluminum. 
     
     
         5 . The processing chamber of  claim 1 , wherein the vertical extension includes cut-outs therein to accommodate a tool. 
     
     
         6 . The processing chamber of  claim 1 , wherein the electrically conductive bracket further comprises an upper portion coupled to the plate and positioned substantially parallel to the lower portion. 
     
     
         7 . The processing chamber of  claim 1 , wherein there is substantially no space between the electrically conductive bracket and the electrical isolator. 
     
     
         8 . The processing chamber of  claim 7 , wherein the electrically conductive bracket comprises aluminum. 
     
     
         9 . The processing chamber of  claim 1 , wherein the electrically conductive bracket is flexible. 
     
     
         10 . A processing chamber, comprising:
 a chamber body;   a chamber lid positioned on the chamber body;   a backing plate coupled to the chamber lid;   a showerhead coupled to the backing plate;   an electrically conductive bracket coupled to the backing plate and spaced apart from the showerhead, the electrically conductive bracket comprising:
 a plate positioned substantially perpendicular to a face of the showerhead; 
 a lower portion coupled to a bottom edge of the plate, the lower portion substantially perpendicular to the plate; and 
 an upper portion extending from the plate and positioned parallel with the lower portion; and 
   a first electrical isolator comprising polytetrafluoroethylene positioned proximate to the backing plate, the chamber body, and the showerhead, the electrical isolator having a first side contacting the chamber body and a second side contacting the plate of the electrically conductive bracket.   
     
     
         11 . The processing chamber of  claim 10 , wherein there is substantially no space between the first electrical isolator and the plate of the electrically conductive bracket. 
     
     
         12 . The processing chamber of  claim 10 , further comprising a second electrical isolator disposed between and electrically isolating the chamber body and the backing plate. 
     
     
         13 . The processing chamber of  claim 12 , wherein the electrically conductive bracket comprises aluminum. 
     
     
         14 . The processing chamber of  claim 10 , wherein the lower portion of the electrically conductive bracket and the plate of the electrically conductive bracket are connected at a right angle to one another. 
     
     
         15 . The processing chamber of  claim 10 , wherein the substrate processing chamber is a PECVD chamber. 
     
     
         16 . The processing chamber of  claim 10 , wherein the plate, the lower portion and the upper portion each have one or more holes disposed therethrough. 
     
     
         17 . A processing chamber, comprising:
 a chamber body;   a chamber lid positioned on the chamber body;   a backing plate coupled to the chamber lid;   a showerhead coupled to the backing plate;   an electrically conductive bracket coupled to the backing plate and spaced apart from the showerhead, the electrically conductive bracket comprising:
 a plate positioned substantially perpendicular to a face of the showerhead; 
 a lower portion coupled to a bottom edge of the plate, the lower portion substantially perpendicular to the plate; 
 a vertical extension coupled to the lower portion, the vertical extension parallel to the plate; and 
 an upper portion extending from the plate and positioned parallel with the lower portion; and 
   a first electrical isolator comprising one or more of ceramic, alumina, and polytetrafluoroethylene positioned proximate to the backing plate, the chamber body, and the showerhead, the electrical isolator having a first side contacting the chamber body and a second side contacting the plate of the electrically conductive bracket.   
     
     
         18 . The processing chamber of  claim 17 , wherein the electrically conductive bracket comprises aluminum. 
     
     
         19 . The processing chamber of  claim 18 , wherein the processing chamber is a PECVD chamber, and the PECVD chamber further comprises an RF source coupled to the backing plate. 
     
     
         20 . The processing chamber of  claim 19 , wherein the vertical extension includes cut-outs therein to accommodate a tool.