Apparatus for polishing wafer and process for polishing wafer

Abstract

An apparatus for polishing wafers and a process for polishing wafers are provided. The apparatus for polishing a wafer which polishes the wafer W held by a carrier plate which rotates around an axis, by pressing and rubbing the wafer to a polishing pad disposed to a polishing platen 12 which rotates around another axis which differs from said axis, in which the polishing pad 11 is equipped with plural areas including a first area 11 a and a second area 11 b having hardness different from each other, each of the first 11 a area and second area 11 b being formed at a distribution and/or an area ratio such that the rate of the time or distance that the wafer W passes through the first area 11 a during polishing to the time or distance that the wafer W passes through the second area 11 b during polishing becomes a predetermined value.

1 . An apparatus for polishing a wafer which polishes the wafer held by a carrier plate which rotates around an axis, by pressing and rubbing the wafer to a polishing pad disposed to a polishing platen which rotates around another axis which differs from said axis, 
 wherein said polishing pad is equipped with plural areas including a first area and a second area having hardness different from each other, each of said first area and second area being formed at a distribution and/or an area ratio such that the rate of the time or distance that said wafer passes through said first area during polishing to the time or distance that said wafer passes through said second area during polishing becomes a predetermined value.    
     
     
         2 . The apparatus for polishing a wafer as set forth in  claim 1 , wherein each of said first area and said second area is shaped into a planar sector, and said first area and said second area are arranged alternately to constitute said plural areas.  
     
     
         3 . The apparatus for polishing a wafer as set forth in  claim 1 , wherein each of said first area and said second area is shaped into a planar spiral, and said first area and said second area are arranged alternately to constitute said plural areas.  
     
     
         4 . A process for polishing a wafer comprising rotating a polishing pad equipped with plural areas including a first area and a second area having hardness different from each other, and pressing and rubbing a wafer which rotates to said polishing pad thereby polishing surface of said wafer.