Patent ID: 6285035
Filing Date: 2001-09-04
Classification: B24B,H01L

Abstract:
An apparatus for polishing a first side of a semiconductor wafer down to a desired level, comprising:a polishing platen having a polishing surface;a wafer carrier having a first sub-carrier and a second sub-carrier which is concentric to said first sub-carrier, wherein (i) said first sub-carrier is configured to (a) engage a first radial portion of said wafer by a second side of said wafer, and (b) apply first pressure to said first radial portion in order to press said first radial portion against said polishing surface of said polishing platen, and (ii) said second sub-carrier is configured to (a) engage a second radial portion of said wafer by said second side of said wafer, and (b) apply second pressure to said second radial portion in order to press said second radial portion against said polishing surface of said polishing platen;a first endpoint detector operable to (i) determine when said first radial portion of said wafer has reached said desired level, and (ii) cause said first sub-carrier to adjust said first pressure applied to said first radial portion of said wafer in response to determining that said first radial portion has reach said desired level; anda second endpoint detector operable to (i) determine when said second radial portion of said wafer has reached said desired level, and (ii) cause said second sub-carrier to adjust said second pressure applied to said second radial portion of said wafer in response to determining that said second radial portion has reach said desired level.