Method for hardening the wear portion of a retaining ring

Abstract

A one piece plastic or two piece, metal and plastic, retaining ring used for chemical mechanical polishing of semiconductor substrates. In one embodiment, the plastic is selected from polyphenylene sulfide (PPS), polyethylene terephthalate, polyetheretherketone, polybutylene terephthalate, Ertalyte TX, PEEK, Torlon, Delrin, PET, Vespel, or Duratrol. The plastic wear surface is hardened by electron beam or gamma ray irradiation.

1 . A method of fabricating a multilayer retaining ring for a CMP carrier head the method 
 comprising    machining a metal upper portion;    machining a lower plastic portion;    attaching the lower portion to the upper portion, such that the plastic portion has an exposed bottom surface; and    treating the exposed plastic bottom surface with electron beam irradiation, thereby hardening the surface of the plastic portion.    
     
     
         2 . The method of  claim 1  wherein 
 the plastic is selected from the group from a material selected from the group consisting of polyphenylene sulfide (PPS), polyethylene terephthalate, polyetheretherketone, polybutylene terephthalate, Ertalyte TX, PEEK, Torlon, Delrin, PET, Vespel, or Duratrol;    
     
     
         3 . A method of fabricating a multilayer retaining ring for a CMP carrier head the method 
 comprising    machining a metal upper portion;    machining a lower plastic portion;    attaching the lower portion to the upper portion, such that the plastic portion has an exposed bottom surface; and    treating the exposed plate surface with gamma ray irradiation, thereby hardening at least the surface of the plastic portion.    
     
     
         4 . The method of  claim 1  wherein 
 the plastic portion is selected from the group consisting of polyphenylene sulfide (PPS), polyethylene terephthalate, polyetheretherketone, polybutylene terephthalate, Ertalyte TX, PEEK, Torlon, Delrin, PET, Vespel, or Duratrol.    
     
     
         5 . A method of fabricating a plastic retaining ring, the method comprising 
 machining the plastic ring, the ring having a lower wear surface; and    hardening at least the wear surface of the ring with a radiation process.    
     
     
         6 . The method of  claim 5  wherein 
 the radiation process is an electron beam process.    
     
     
         7 . The method of  claim 5  wherein 
 the radiation process is a gamma ray process.