Process kit for erosion resistance enhancement

Abstract

A process kit is described that resists plasma erosion, preserves the spatial uniformity of plasma properties, reduces particle generation in the chamber, and significantly enhances the lifetime of the process kit. A layer of polymer material covers the top surface of the process kit. The polymer material is fluorocarbon-based and not reactive with the species in the plasma. The polymer material not only protects the process kit from progressive erosion, but also prevents the generation of particles in the chamber. The polymer material has similar permittivity to that of the process kit and therefore maintains the spatial uniformity of plasma properties, e.g., etch rate, near the wafer perimeter. The thickness of the layer is controlled between 0.5 and 1.5 mm such that the difference between its coefficient of thermal expansion and that of the process kit will not cause the layer to peel off the process kit's top surface.

1 . A process kit for erosion resistance enhancement in a plasma etching chamber comprising: 
 a ring shaped to surround a semiconductor wafer; and    a layer of polymer material covering at least the top surface of the ring.    
   
   
       2 . The process kit of  claim 1  wherein the ring is made of quartz.  
   
   
       3 . The process kit of  claim 1  wherein the polymer material is a fluorocarbon-based material.  
   
   
       4 . The process kit of  claim 1  wherein the polymer material is Polytetrafluoroethylene.  
   
   
       5 . The process kit of  claim 1  wherein the polymer material completely covers at least the top surface of the ring.  
   
   
       6 . The process kit of  claim 1  wherein the polymer material is not reactive with any etchant in the plasma.  
   
   
       7 . The process kit of  claim 1  wherein the polymer material has similar permittivity to that of silicon oxide.  
   
   
       8 . The process kit of  claim 1  wherein the thickness of the layer of polymer material is between 0.5 and 1.5 mm.  
   
   
       9 . The process kit of  claim 1  wherein the polymer material is sputtered onto the surface of the ring.  
   
   
       10 . The process kit of  claim 1  wherein the polymer material is coated onto the surface of the ring.