Capacitively coupled plasma reactor with magnetic plasma control

Abstract

A plasma reactor includes a vacuum enclosure including a side wall and a ceiling defining a vacuum chamber, and a workpiece support within the chamber and facing the ceiling for supporting a planar workpiece, the workpiece support and the ceiling together defining a processing region between the workpiece support and the ceiling. Process gas inlets furnish a process gas into the chamber. A plasma source power electrode is connected to an RF power generator for capacitively coupling plasma source power into the chamber for maintaining a plasma within the chamber. The reactor further includes at least a first overhead solenoidal electromagnet adjacent the ceiling, the overhead solenoidal electromagnet, the ceiling, the side wall and the workpiece support being located along a common axis of symmetry.

1 . A wafer processing apparatus, comprising: 
 a housing defining a process chamber    a wafer support configured to support a wafer within the chamber during processing;    a first process gas inlet;    a second process gas inlet;    a gas distribution system, comprising: 
 a center circular gas disperser configured to receive a process gas from the first process gas inlet and to distribute the process gas into the chamber over the wafer through a first plurality of injection ports; and  
 an outer annular gas disperser centered around the center gas disperser configured to receive the process gas from the second process gas inlet and to distribute the process gas into the chamber over the wafer through a second plurality of injection ports.  
   
   
   
       2 . The apparatus of  claim 1  wherein the first and second plurality of injection ports are annular.  
   
   
       3 . The apparatus of  claim 1  wherein the first and second plurality of injection ports are circular holes, wherein the holes have diameters ranging between 0.01 and 0.03 inches.  
   
   
       4 . The apparatus of  claim 1  wherein the gas distribution system comprises an annular wall that separates the center gas disperser and the outer gas disperser.  
   
   
       5 . The apparatus of  claim 1  further comprising: 
 a first gas flow controller coupled to the first process gas inlet, wherein the first gas flow controller can be independently controlled to adjust the amount of the process gas flowing into the center gas disperser;    a second gas flow controller coupled to the second process gas inlet; and    wherein the first and the second gas flow controllers can be independently controlled to adjust the amount of the process gas flowing into the center circular gas disperser relative to the amount of process gas flowing into the outer annular gas disperser.    
   
   
       6 . The apparatus of  claim 5  wherein the first gas flow controller comprises a first valve and wherein the second gas flow controller comprises a second valve.  
   
   
       7 . The apparatus of  claim 5  further comprising a dual zone controller coupled to the first gas flow controller and the second gas flow controller, the dual zone controller configured to adjust flow through the first gas flow controller and through the second gas flow controller.  
   
   
       8 . A wafer processing apparatus, comprising: 
 a housing defining a processing chamber, the housing coupled to an RF ground;    a substrate support located in a chamber configured to support a wafer during processing;    first and second process gas inlets configured to deliver a process gas into the chamber;    a gas distribution system comprising a circular gas disperser having a circular center gas dispersing region fluidly coupled to the first process gas inlet and an annular gas dispersing region surrounding the center region and fluidly coupled to the second process gas inlet, wherein the center gas dispersing region comprises a first plurality of gas injection holes configured to introduce the process gas into the chamber above a wafer supported on the substrate support and the annular gas dispersing region comprises a second plurality of gas injection holes configured to introduce the process gas into the chamber annularly to the center gas dispersion region above the wafer; and    an RF generator coupled to an impedance match circuit used to provide RF power to the wafer support, wherein the impedance match circuit is coupled to the wafer support and wherein the RF generator is coupled to the RF ground.    
   
   
       9 . The apparatus of  claim 8  wherein the first and second plurality of gas injections holes are annular.  
   
   
       10 . The apparatus of  claim 8  wherein the first and second plurality of injection holes have diameters ranging between 0.01 and 0.03 inches.  
   
   
       11 . The apparatus of  claim 8  wherein the gas distribution system comprises an annular wall that forms a boundary separating the center gas disperser and the outer gas disperser.  
   
   
       12 . The apparatus of  claim 8  wherein the first plurality of gas injection holes are configured to introduce the process gas into a center portion of a wafer supported on the substrate support and the second plurality of gas injection holes are configured to introduce the process gas into the chamber above an outer peripheral portion of the wafer.  
   
   
       13 . The apparatus of  claim 8  further comprising: 
 a first gas flow controller coupled to the first process gas inlet, wherein the first gas flow controller can be independently controlled to adjust the amount of the process gas flowing into the center gas disperser; and    a second gas flow controller coupled to the second process gas inlet, wherein the second gas flow controller can be independently controlled to adjust the amount of the process gas flowing into the outer annular gas disperser.    
   
   
       14 . The apparatus of  claim 13  further comprising a dual zone controller coupled to the first gas flow controller and the second gas flow controller, the dual zone controller configured to adjust flow through the first gas flow controller and through the second gas flow controller.  
   
   
       15 . The apparatus of  claim 8  further comprising an annular pumping channel below and surrounding the wafer support coupled to an exhaust line.  
   
   
       16 . A wafer processing apparatus, comprising: 
 a vacuum chamber configured to support a plasma;    a process gas inlet configured to deliver a process gas used for the plasma into the vacuum chamber;    a gas disperser coupled to the process gas inlet, comprising: 
 a base having a plurality of injection ports formed throughout, surrounded by an annular wall having an interior shoulder;  
 a cover having a top surface, a bottom surface and a plurality of fingers, the plurality of fingers attached to the bottom surface and extending downwardly from the bottom surface, the top surface coupled to the process gas inlet; and  
 wherein the fingers extend into the injection ports of the base to form a plurality of annular ports in the base for the process gas to flow from the gas disperser to a processing region.  
   
   
   
       17 . The apparatus of  claim 16  wherein the plurality of injection ports are circular holes, wherein the holes have diameters ranging between 0.01 and 0.03 inches.  
   
   
       18 . The apparatus of  claim 17  further comprising an annular wall positioned between the base and the cover forming a center gas disperser and an outer gas disperser.  
   
   
       19 . The apparatus of  claim 18  further comprising a second process gas inlet coupled to the top surface of the cover and positioned to be over the outer gas disperser.  
   
   
       20 . The apparatus of  claim 19  further comprising: 
 a first gas flow controller coupled to the process gas inlet, wherein the first gas flow controller can be independently controlled to adjust the amount of the process gas flowing into the center gas disperser; and    a second gas flow controller coupled to the second process gas inlet, wherein the second gas flow controller can be independently controlled to adjust the amount of the process gas flowing into the outer gas disperser.    
   
   
       21 . The apparatus of  claim 19  further comprising a dual zone controller coupled to the first gas flow controller and the second gas flow controller, the dual zone controller configured to adjust flow through the first gas flow controller and through the second gas flow controller.