Inductively coupled plasma source using induced eddy currents

Abstract

Methods and apparatus are provided for generating an inductively coupled plasma using induced eddy currents. An inductively coupled plasma source of the invention generally comprises a body constructed substantially of a conductive material interrupted by at least one dielectric gap. Radio frequency power is coupled from a current carrier into the conductive body. The one or more dielectric interruptions in the conductive body are disposed so as to cause eddy currents to circulate about portions of the body and thereby couple RF power into a plasma in proximity to the conductive body. By utilizing induced eddy currents to couple power into a plasma, the invention allows for substantial bodies of conductive materials, such as structural metals, to be interposed between the induction coils that receive power from a power generator and the plasma.

1 . A plasma source apparatus, comprising: 
 a) a substantially conductive body comprising one or more conductive segments interrupted by at least one dielectric break;    b) a current carrier adjacent to the substantially conductive body; and    c) a power supply that furnishes alternating current power to the current carrier, the current carrier inducing eddy currents within the one or more conductive segments, the eddy currents coupling power into a plasma adjacent to the substantially conductive body.    
   
   
       2 . The apparatus of  claim 1  wherein the substantially conductive body forms at least a portion of a plasma chamber that substantially confines the plasma.  
   
   
       3 . The apparatus of  claim 2  wherein the plasma chamber is substantially cylindrical and the at least one dielectric break comprises one or more grooves that separate at least a portion of the chamber into the conductive segments.  
   
   
       4 . The apparatus of  claim 3  wherein the conductive segments are longitudinally aligned, and wherein the current carrier is an induction coil disposed coaxially about the plasma chamber.  
   
   
       5 . The apparatus of  claim 3  wherein the one or more grooves are covered by gastight dielectric seals.  
   
   
       6 . The apparatus of  claim 2  wherein the plasma chamber is a substantially cylindrical body formed by longitudinal alignment of the conductive segments, and wherein the current carrier is an induction coil disposed coaxially about the plasma chamber.  
   
   
       7 . The apparatus of  claim 6  wherein the at least one dielectric break comprises an insulating layer disposed upon mating surfaces of the conductive segments.  
   
   
       8 . The apparatus of  claim 7  wherein the insulating layer results from an anodization treatment of one or more of the mating surfaces.  
   
   
       9 . The apparatus of  claim 7  wherein the insulating layer comprises a dielectric adhesive.  
   
   
       10 . The apparatus of  claim 1  wherein one or more cooling channels is disposed within at least one of the conductive segments.  
   
   
       11 . The apparatus of  claim 1  wherein the current carrier is disposed within a hollow region of the substantially conductive body.  
   
   
       12 . The apparatus of  claim 1 , further comprising at least one inlet for a gas to enter the plasma chamber.  
   
   
       13 . The apparatus of  claim 1  wherein the dielectric break interrupts a wall of a cavity in at least one of the one or more conductive segments.  
   
   
       14 . A plasma processing system, comprising: 
 a) a substantially conductive body comprising one or more conductive segments interrupted by at least one dielectric break;    b) a current carrier adjacent to the substantially conductive body; and    c) a power supply that furnishes alternating current power to the current carrier, the current carrier inducing eddy currents within the one or more conductive segments, the eddy currents coupling power into a plasma adjacent to the substantially conductive body.    
   
   
       15 . The system of  claim 14 , further comprising a plasma chamber that substantially contains the plasma.  
   
   
       16 . The system of  claim 15  wherein the substantially conductive body forms at least one portion of the plasma chamber.  
   
   
       17 . The system of  claim 16  wherein the plasma chamber is a substantially cylindrical body formed by longitudinal alignment of the conductive segments, and wherein the current carrier is an induction coil disposed coaxially about the plasma chamber.  
   
   
       18 . The system of  claim 16  wherein the substantially conductive body is a planar disk formed by radial dispersal of the conductive segments, and wherein the current carrier is a helical induction coil disposed adjacent to the planar disk.  
   
   
       19 . The system of  claim 16  wherein the substantially conductive body is a conformal dome formed by radial dispersal of the conductive segments, and wherein the current carrier is a helical induction coil disposed about the conformal dome.  
   
   
       20 . The system of  claim 15 , further comprising a first gas inlet for injection of a processing gas into the plasma chamber.  
   
   
       21 . The system of  claim 20 , further comprising a second gas inlet for injection of a precursor gas into the plasma.  
   
   
       22 . A method of plasma processing, comprising: 
 a) providing a substantially conductive body comprised of one or more conductive segments interrupted by at least one dielectric break;    b) inducing eddy currents in the conductive segments by furnishing alternating current power to a current carrier disposed adjacent to the substantially conductive body; and    c) coupling power into a plasma adjacent to the substantially conductive body using the induced eddy currents.    
   
   
       23 . The method of  claim 22  wherein the plasma is substantially contained within a plasma chamber.  
   
   
       24 . The method of  claim 23  wherein the substantially conductive body forms at least one portion of the plasma chamber.  
   
   
       25 . The method of  claim 22 , further comprising the step of dissociating a feed gas in the plasma.  
   
   
       26 . The method of  claim 22 , further comprising the step of abating a feed gas in the plasma.  
   
   
       27 . The method of  claim 22 , further comprising the step of etching material from a workpiece using the plasma.  
   
   
       28 . The method of  claim 22 , further comprising the step of depositing material from the plasma upon a workpiece.  
   
   
       29 . The method of  claim 23 , further comprising the steps of injecting a feed gas into the plasma chamber to form an activated gas; injecting a precursor gas into the plasma, the precursor gas reacting with the activated gas to form a vapor deposition compound; and depositing the vapor deposition compound upon a workpiece.