Method and apparatus for polishing a substrate

Abstract

A substrate such as a semiconductor wafer, a glass substrate, or a liquid crystal display is polished to a flat mirror finish, and then is cleaned to a high degree of cleanliness. A polishing section having at least one polishing unit performs primary polishing and secondary polishing of the substrate by pressing the substrate against a polishing surface. A cleaning section cleans the substrate which has been polished to remove particles attached to the substrate by a scrubbing cleaning. Metal ions are removed from the substrate by supplying an etching liquid.

What is claimed is:  
     
         1 . A method of polishing and then cleaning a substrate, comprising: 
 polishing a substrate by pressing said substrate against a polishing surface; then    primarily cleaning said substrate in at least one of two first cleaning units; and then    secondarily cleaning said substrate in a common second cleaning unit, wherein said common second cleaning unit is constructed and arranged to receive a substrate from each of said two first cleaning units.    
     
     
         2 . The method according to  claim 1 , wherein 
 primarily cleaning said substrate comprises primarily cleaning said substrate in each of said two first cleaning units.    
     
     
         3 . The method according to  claim 2 , wherein 
 primarily cleaning said substrate in each of said two first cleaning units comprises cleaning said substrate in each of said two first cleaning units by subjecting said substrate to the same cleaning function in said each of said two first cleaning units.    
     
     
         4 . The method according to  claim 2 , further comprising: 
 drying said substrate after secondarily cleaning said substrate.    
     
     
         5 . The method according to  claim 2 , wherein 
 primarily cleaning said substrate comprises supplying an etching liquid to said substrate, or    secondarily cleaning said substrate comprises supplying an etching liquid to said substrate.    
     
     
         6 . The method according to  claim 2 , wherein 
 primarily cleaning said substrate in each of said two first cleaning units comprises primarily cleaning said substrate in each of said two first cleaning units for a time period that is greater than a time period for which said substrate is secondarily cleaned in said common second cleaning unit.    
     
     
         7 . The method according to  claim 2 , wherein 
 primarily cleaning said substrate comprises using ionic water, ozone water, or hydrogenated water as a cleaning liquid, or    secondarily cleaning said substrate comprises using ionic water, ozone water, or hydrogenated water as a cleaning liquid.    
     
     
         8 . The method according to  claim 2 , wherein 
 primarily cleaning said substrate in each of said two first cleaning units comprises primarily cleaning said substrate in each of two first cleaning units that are arranged parallel to one another.    
     
     
         9 . The method according to  claim 1 , further comprising: 
 polishing another substrate by pressing said another substrate against a polishing surface; then    primarily cleaning said another substrate in a first of said two first cleaning units; and then    secondarily cleaning said another substrate in said common second cleaning unit, wherein    primarily cleaning said substrate in at least one of said two first cleaning units comprises primarily cleaning said substrate in a second of said two first cleaning units.    
     
     
         10 . The method according to  claim 9 , wherein 
 primarily cleaning said substrate in said second of said two first cleaning units comprises cleaning said substrate in said second of said two first cleaning units by subjecting said substrate to a first cleaning function, and    primarily cleaning said another substrate in said first of said two first cleaning units comprises cleaning said another substrate in said first of said two first cleaning units by subjecting said another substrate to a second cleaning function that is the same as said first cleaning function.    
     
     
         11 . The method according to  claim 9 , further comprising: 
 drying said substrate and said another substrate after secondarily cleaning said substrate and said another substrate.    
     
     
         12 . The method according to  claim 9 , wherein 
 primarily cleaning said substrate and said another substrate comprises supplying an etching liquid to said substrate and said another substrate, or    secondarily cleaning said substrate and said another substrate comprises supplying an etching liquid to said substrate and said another substrate.    
     
     
         13 . The method according to  claim 9 , wherein 
 primarily cleaning said substrate in said second of said two first cleaning units comprises primarily cleaning said substrate in said second of said two first cleaning units for a time period that is greater than a time period for which said substrate is secondarily cleaned in said common second cleaning unit, and    primarily cleaning said another substrate in said first of said two first cleaning units comprises primarily cleaning said another substrate in said first of said two first cleaning units for a time period that is greater than a time period for which said another substrate is secondarily cleaned in said common second cleaning unit.    
     
     
         14 . The method according to  claim 9 , wherein 
 primarily cleaning said substrate and said another substrate comprises using ionic water, ozone water, or hydrogenated water as a cleaning liquid, or    secondarily cleaning said substrate and said another substrate comprises using ionic water, ozone water, or hydrogenated water as a cleaning liquid.    
     
     
         15 . The method according to  claim 9 , wherein 
 primarily cleaning said substrate and primarily cleaning said another substrate comprises primarily cleaning said substrate in parallel with primarily cleaning said another substrate.    
     
     
         16 . The method according to  claim 1 , wherein 
 primarily cleaning said substrate in at least one of said two first cleaning units comprises cleaning said substrate in said at least one of said two first cleaning units by subjecting said substrate to a cleaning function that is the same as a cleaning function to be performed in the other of said two first cleaning units.    
     
     
         17 . The method according to  claim 1 , further comprising: 
 drying said substrate after secondarily cleaning said substrate.    
     
     
         18 . The method according to  claim 1 , wherein 
 primarily cleaning said substrate comprises supplying an etching liquid to said substrate, or    secondarily cleaning said substrate comprises supplying an etching liquid to said substrate.    
     
     
         19 . The method according to  claim 1 , wherein 
 primarily cleaning said substrate in at least one of said two first cleaning units comprises primarily cleaning said substrate in said at least one of said two first cleaning units for a time period that is greater than a time period for which said substrate is secondarily cleaned in said common second cleaning unit.    
     
     
         20 . The method according to  claim 1 , wherein 
 primarily cleaning said substrate comprises using ionic water, ozone water, or hydrogenated water as a cleaning liquid, or    secondarily cleaning said substrate comprises using ionic water, ozone water, or hydrogenated water as a cleaning liquid.    
     
     
         21 . The method according to  claim 1 , wherein 
 primarily cleaning said substrate in at least one of said two first cleaning units comprises primarily cleaning said substrate in at least one of two first cleaning units that are arranged parallel to one another.