Rf grounding configuration for pedestals

Abstract

Embodiments of the present disclosure generally relate to substrate supports for process chambers and RF grounding configurations for use therewith. Methods of grounding RF current are also described. A chamber body at least partially defines a process volume therein. A first electrode is disposed in the process volume. A pedestal is disposed opposite the first electrode. A second electrode is disposed in the pedestal. An RF filter is coupled to the second electrode through a conductive rod. The RF filter includes a first capacitor coupled to the conductive rod and to ground. The RF filter also includes a first inductor coupled to a feedthrough box. The feedthrough box includes a second capacitor and a second inductor coupled in series. A direct current (DC) power supply for the second electrode is coupled between the second capacitor and the second inductor.

What is claimed is: 
     
         1 . An apparatus, comprising:
 a pedestal;   an electrode disposed in the pedestal;   a conductive rod coupled to the electrode; and   a radio frequency (RF) filter, the RF filter comprising:
 a first capacitor coupled to the conductive rod and configured to be coupled to ground; 
 an LC resonant circuit coupled to the conductive rod; and 
 a second capacitor coupled to the LC resonant circuit and configured to be coupled to ground. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the LC resonant circuit and the second capacitor are downstream of the first capacitor. 
     
     
         3 . The apparatus of  claim 1 , further comprising:
 a power supply coupled to the electrode through the LC resonant circuit and the conductive rod.   
     
     
         4 . The apparatus of  claim 3 , wherein the power supply is a direct current (DC) power supply configured to provide direct current to the electrode. 
     
     
         5 . The apparatus of  claim 1 , wherein the LC resonant circuit includes a third capacitor and an inductor coupled in parallel. 
     
     
         6 . The apparatus of  claim 5 , wherein the RF filter is disposed in a housing that is configured to be coupled to ground. 
     
     
         7 . The apparatus of  claim 6 , wherein the housing is an enclosure. 
     
     
         8 . The apparatus of  claim 6 , wherein the first capacitor and the third capacitor are coupled to the housing, and the housing is electrically conductive. 
     
     
         9 . The apparatus of  claim 8 , wherein the conductive rod extends through a top of the housing. 
     
     
         10 . The apparatus of  claim 9 , wherein the pedestal comprises a substrate support and a shaft coupled to the substrate support. 
     
     
         11 . The apparatus of  claim 10 , wherein the conductive rod extends through the shaft of the pedestal. 
     
     
         12 . An apparatus, comprising:
 a chamber body at least partially defining a process volume therein;   a pedestal disposed in the process volume, the pedestal comprising a substrate support and a shaft coupled to the substrate support;   a first electrode disposed in the process volume opposite the pedestal;   a second electrode disposed in the pedestal;   a conductive rod extending through the shaft of the pedestal, the conductive rod coupled to the second electrode; and   a radio frequency (RF) filter disposed in a housing and coupled to the conductive rod, the RF filter comprising:
 a first capacitor coupled to the conductive rod and coupled to the housing, 
 an LC resonant circuit coupled to the conductive rod, and 
 a second capacitor coupled to the LC resonant circuit and coupled to the housing. 
   
     
     
         13 . The apparatus of  claim 12 , further comprising:
 a power supply coupled to the second electrode through the LC resonant circuit and the conductive rod.   
     
     
         14 . The apparatus of  claim 13 , further comprising:
 an RF cable extending at least partially between the housing and the power supply, the RF cable disposed in series with the LC resonant circuit.   
     
     
         15 . The apparatus of  claim 14 , wherein the second capacitor couples the RF cable to the housing. 
     
     
         16 . The apparatus of  claim 12 , wherein the housing is coupled to ground and the conductive rod extends through a top of the housing, and the housing is electrically conductive. 
     
     
         17 . The apparatus of  claim 16 , wherein the housing extends at least partially through the chamber body, and the housing surrounds the first capacitor, the LC resonant circuit, and the second capacitor. 
     
     
         18 . An apparatus for processing a substrate, comprising:
 a pedestal comprising a substrate support and a shaft;   an electrode disposed in the pedestal;   a conductive rod coupled to the electrode;   an RF filter coupled to the conductive rod, the RF filter comprising:
 a housing coupled to ground, 
 a first capacitor coupled between the conductive rod and the housing, and 
 a first inductor coupled to the conductive rod; 
   a feedthrough box coupled to ground, the feedthrough box having a second inductor and a second capacitor coupled in series disposed therein, the second capacitor coupled between the second inductor and the feedthrough box; and   an RF cable extending at least partially between the housing and the feedthrough box, the RF cable disposed in series with the RF filter and the second inductor of the feedthrough box.   
     
     
         19 . The apparatus of  claim 18 , wherein the conductive rod extends through the shaft and through a top of the housing, and the housing is electrically conductive. 
     
     
         20 . The apparatus of  claim 19 , further comprising:
 a power supply coupled to the electrode through the second inductor and the RF filter;   a second electrode; and   an RF source coupled to the second electrode.