Polishing method

Abstract

A wafer is pressed against a fixed abrasive and brought into sliding contact with the fixed abrasive. Thus, the wafer is polished. A surface of the fixed abrasive is dressed so as to generate free abrasive particles thereon. A liquid or a gas, composed of a mixture of liquid or inert gas and pure water or chemical liquid, is ejected onto the surface of the fixed abrasive during or after the dressing process.

1 . A method comprising: 
 polishing a workpiece by pressing said workpiece against a fixed abrasive and bringing said workpiece into sliding contact with said fixed abrasive; and then    water-polishing said workpiece while supplying pure water to said fixed abrasive,    wherein surface pressure of said workpiece during the water-polishing is set to be smaller than that during the polishing using said fixed abrasive.    
   
   
       2 . The method according to  claim 1 , wherein the water-polishing comprises increasing a rotational speed of a polishing table.  
   
   
       3 . The method according to  claim 1 , wherein the water-polishing comprises supplying said pure water at a flow rate larger than a flow rate of a polishing liquid supplied during the polishing using said fixed abrasive.  
   
   
       4 . The method ac cording to  claim 1 , further comprising: 
 removing said workpiece from said fixed abrasive after the water-polishing,    wherein the removing comprises reducing a rotational speed of a polishing table as compared to a rotational speed of the polishing table during the polishing using said fixed abrasive.    
   
   
       5 . A method comprising: 
 polishing a workpiece with a fixed abrasive while supplying a chemical liquid to a surface of said fixed abrasive; and    simultaneously ejecting at least one of a liquid containing the chemical liquid, and a fluid composed of a mixture of inert gas and the chemical liquid, onto said surface of said fixed abrasive.    
   
   
       6 . The method according to  claim 5 , wherein the chemical liquid comprises an anionic surface-active agent.  
   
   
       7 . The method according to  claim 6 , wherein the workpiece comprises a semiconductor wafer on which a pattern of STI is formed.  
   
   
       8 . A polishing apparatus comprising: 
 a holding device for holding a workpiece;    a polishing table having a fixed abrasive thereon, said fixed abrasive including abrasive particles and a binder;    a dressing device for generating free abrasive particles from said fixed abrasive;    an ejection nozzle for ejecting a fluid onto a surface of said fixed abrasive to remove massive particles, which adversely affect a polishing process, from the surface of said fixed abrasive;    a controller for adjusting a relative speed between said polishing table and said holding device; and    a controller for adjusting a pressing force produced between said polishing table and said holding device.