Polishing apparatus and polishing method

Abstract

A polishing apparatus for polishing a periphery of a substrate includes a substrate holder configured to rotate the substrate, a first polishing section configured to polish the periphery of the substrate by bringing a polishing layer of a first polishing tool into contact with the periphery of the substrate when rotated by the substrate holder, and a second polishing section configured to polish the periphery of the substrate by bringing a polishing layer of a second polishing tool into contact with the periphery of the substrate when rotated by the substrate holder. The polishing layer of the first polishing tool has hard first abrasive grains, and the polishing layer of the second polishing tool has second abrasive grains that are softer than the first abrasive grains.

1 . A polishing apparatus for polishing a periphery of a substrate, said polishing apparatus comprising:
 a substrate holder configured to rotate the substrate;   a first polishing section configured to polish the periphery of the substrate by bringing a polishing layer of a first polishing tool into contact with the periphery of the substrate when rotated by said substrate holder; and   a second polishing section configured to polish the periphery of the substrate by bringing a polishing layer of a second polishing tool into contact with the periphery of the substrate when rotated by said substrate holder,   wherein said polishing layer of said first polishing tool has hard first abrasive grains, and   said polishing layer of said second polishing tool has second abrasive grains that are softer than said first abrasive grains.   
   
   
       2 . The polishing apparatus according to  claim 1 , wherein at least one of said polishing layer of said first polishing tool and said polishing layer of said second polishing tool has said first abrasive grains and said second abrasive grains. 
   
   
       3 . The polishing apparatus according to  claim 1 , wherein:
 said first abrasive grains are diamond abrasive grains; and   said second abrasive grains are one of cerium oxide abrasive grains and silica abrasive grains.   
   
   
       4 . The polishing apparatus according to  claim 3 , further comprising:
 a third polishing section configured to polish the periphery of the substrate by bringing a polishing layer of a third polishing tool into contact with the periphery of the substrate when rotated by said substrate holder,   wherein said second abrasive grains are cerium oxide abrasive grains, and   said polishing layer of said third polishing tool has silica abrasive grains.   
   
   
       5 . A polishing method for polishing a periphery of a substrate, said polishing method comprising:
 rotating the substrate;   a first polishing process of polishing the periphery of the substrate by bringing a polishing layer of a first polishing tool into contact with the periphery of the rotating substrate, the polishing layer of the first polishing tool having hard first abrasive grains; and   a second polishing process of polishing the periphery of the substrate by bringing a polishing layer of a second polishing tool into contact with the periphery of the rotating substrate, the polishing layer of the second polishing tool having second abrasive grains that are softer than the first abrasive grains.   
   
   
       6 . The polishing method according to  claim 5 , wherein at least one of the polishing layer of the first polishing tool and the polishing layer of the second polishing tool has the first abrasive grains and the second abrasive grains. 
   
   
       7 . The polishing method according to  claim 5 , wherein:
 the first abrasive grains are diamond abrasive grains; and   the second abrasive grains are one of cerium oxide abrasive grains and silica abrasive grains.   
   
   
       8 . The polishing method according to  claim 7 , further comprising:
 a third polishing process of polishing the periphery of the substrate by bringing a polishing layer of a third polishing tool into contact with the periphery of the rotating substrate,   wherein the second abrasive grains are cerium oxide abrasive grains, and   the polishing layer of the third polishing tool has silica abrasive grains.