Cleaning device and method for cleaning polishing cloths used for polishing semiconductor wafers

Abstract

A cleaning device is used to clean a polishing pad and has a first cleaning system with a grinding wheel and a second cleaning system with a distributor for discharging a gas-water mixture at high pressure. The polishing pad, which is arranged on a polishing table, can be set in rotary motion, so that the surface sections that will be cleaned are first preliminarily cleaned by the grinding wheel and are then subjected to a second cleaning by the gas-water mixture of the distributor.

We claim:  
     
         1 . A cleaning device for cleaning a polishing pad, comprises: 
 a first cleaning system including a grinding wheel; and    a second cleaning system including a distributor for discharging a gas-water mixture under high pressure;    said distributor having an elongate shape;    said distributor having an outlet side with a plurality of nozzles;    said distributor positionable above a surface of the polishing pad that will be cleaned while located next to an axis of rotation of the polishing pad; and    said distributor extending in a longitudinal direction not aligned with the axis of rotation of the polishing pad.    
     
     
         2 . The cleaning device according to  claim 1 , wherein: 
 the polishing pad is positionable such that the surface of the polishing pad faces said grinding wheel and said outlet side of said distributor;    said first cleaning system includes a holding arm for positioning said grinding wheel opposite a first section of the surface of the polishing pad;    said second cleaning system includes a holding arm for positioning said distributor opposite a second section of the surface of the polishing pad; and    said polishing pad is mounted to rotate about the axis of rotation.    
     
     
         3 . The cleaning device according to  claim 2 , wherein at least one holding arm, which is selected from a group consisting of said holding arm of said first cleaning system and said holding arm of said second cleaning system, is pivotable.  
     
     
         4 . The cleaning device according to  claim 2 , further comprising: 
 a spray nozzle secured to said holding arm of said first cleaning system;    said spray nozzle for washing off abrasive particles that have been removed from the surface of the polishing pad by said grinding wheel.    
     
     
         5 . The cleaning device according to  claim 2 , further comprising a liquid nozzle configured for applying a liquid to a third section of the surface of the polishing pad.  
     
     
         6 . The cleaning device according to  claim 5 , wherein the liquid is water.  
     
     
         7 . The cleaning device according to  claim 1 , in combination with the polishing pad, wherein: 
 the polishing pad is a substantially circular polishing pad; and    said grinding wheel and said distributor are configured at different circumferential sections of the polishing pad.    
     
     
         8 . The cleaning device according to  claim 1 , in combination with the polishing pad, wherein: 
 the polishing pad is a substantially circular polishing pad;    the cleaning device includes a liquid nozzle that is configured to apply a liquid to the surface of the polishing pad; and    said grinding wheel, said distributor, and said liquid nozzle are configured at different circumferential sections of the polishing pad.    
     
     
         9 . The cleaning device according to  claim 1 , in combination with the polishing pad, wherein the polishing pad is a polishing cloth.  
     
     
         10 . A method for cleaning a polishing pad, which comprises: 
 constructing a cleaning device from a first cleaning system having a grinding wheel, and a second cleaning system having a distributor for discharging a gas-water mixture under high pressure;    configuring the distributor with an elongate shape and configuring the distributor with an outlet side having a plurality of nozzles;    providing the cleaning device for cleaning the polishing pad;    positioning the distributor above a surface of the polishing pad that will be cleaned such that the distributor is located next to an axis of rotation of the polishing pad and a longitudinal direction of the distributor is not aligned with the axis of rotation of the polishing pad; and    simultaneously or alternately, grinding down the surface of the polishing pad and directing the gas-water mixture under high pressure onto the surface of the polishing pad.    
     
     
         11 . The method according to  claim 10 , which comprises: 
 simultaneously, grinding down a first section of the surface of the polishing pad and directing the gas-water mixture onto a second, different section of the surface of the polishing pad; and    setting the polishing pad into rotary motion about the axis of rotation so that substantially each section of the surface of the polishing pad is subjected to both the grinding down and the gas-water mixture at least once.    
     
     
         12 . The method according to  claim 10 , which comprises first grinding down the surface of the polishing pad and subsequently directing the gas-water mixture onto the surface of the polishing pad.  
     
     
         13 . The method according to  claim 10 , which comprises alternately grinding down the surface of the polishing pad and subsequently directing the gas-water mixture onto the surface of the polishing pad a number of times in succession.  
     
     
         14 . The method according to  claim 10 , which comprises washing the surface of the polishing pad with a targeted water jet.  
     
     
         15 . The method according to  claim 10 , which comprises using a targeted water jet to wash a surface of the polishing pad that had shortly beforehand been acted on by the gas-water mixture.