Patent ID: 6102786
Filing Date: 2000-08-15
Classification: B24B

Abstract:
An apparatus for polishing a semiconductor wafer to a flat mirror finish, said apparatus comprising:a turntable having an abrasive cloth mounted on an upper surface thereof;a top ring disposed above said turntable for supporting a wafer to be polished and for pressing the wafer against said abrasive cloth, said top ring having a lower wafer-holding area against which the wafer is held during pressing thereof against said abrasive cloth;moving means for moving said turntable and said top ring relative to each other, thereby to cause said abrasive cloth supported by said turntable to polish a surface of the wafer pressed by said top ring against said abrasive cloth, during which polishing areas of the surface of the wafer tend to be polished less intensively at a lower polishing rate than at least one other area of the surface of the wafer, thus tending to create polishing irregularities on the surface of the wafer; andmeans for polishing the areas of the surface of the wafer more intensively than the at least one other area of the surface of the wafer and thereby to correct the polishing irregularities thereof, said means comprising:a surface of said abrasive cloth having a non-projecting region and projecting regions extending upwardly from said non-projecting region;said projecting regions each having a dimension in a radial direction of said turntable that is smaller than a diameter of said wafer-holding area of said top ring;said projecting regions being located at positions relative to said top ring to come into greater contact with the areas of the surface of the wafer than with the at least one other area of the surface of the wafer; andsaid projecting regions being divided into a plurality of groups each having at least one projection region.