Method of processing workpiece

Abstract

A method of processing a workpiece using a chuck table, a grinding unit, a polishing unit, and a measuring unit includes a grinding step of grinding the workpiece with the grinding unit, a measuring step of measuring thicknesses of the workpiece at a plurality of measurement sites and acquiring information with respect to a thickness distribution of the workpiece with the measuring unit, and a polishing step of polishing the workpiece with the polishing unit. The polishing step includes determining polishing conditions based on the information with respect to the thickness distribution of the workpiece acquired in the measuring step and polishing the workpiece under the determined polishing conditions.

What is claimed is: 
     
         1 . A method of processing a workpiece using a chuck table for holding the workpiece, a grinding unit including a grinding wheel for grinding a surface of the workpiece, a polishing unit including a polishing pad for polishing the surface of the workpiece held on the chuck table, and a measuring unit for measuring a thickness of the workpiece, comprising:
 a grinding step of grinding the workpiece from the surface thereof with the grinding unit;   after the grinding step, a measuring step of measuring thicknesses of the workpiece at a plurality of measurement sites thereon with the measuring unit and acquiring information with respect to a thickness distribution of the workpiece with the measuring unit; and   a polishing step of polishing the workpiece from the surface thereof with the polishing unit, wherein   the polishing step includes determining polishing conditions on a basis of the information with respect to the thickness distribution of the workpiece acquired in the measuring step and polishing the workpiece under the determined polishing conditions.   
     
     
         2 . The method of processing a workpiece according to  claim 1 , the method further using a controller for controlling the polishing unit, the controller having a storage section in which a plurality of kinds of polishing conditions are registered, wherein,
 in the polishing step, the controller reads polishing conditions favorable for uniformizing the thickness of the workpiece from among the kinds of polishing conditions registered in the storage section, on the basis of the information with respect to the thickness distribution of the workpiece acquired in the measuring step, and controls the polishing unit to keep polishing the workpiece under the polishing conditions thus read.   
     
     
         3 . The method of processing a workpiece according to  claim 2 , wherein
 the polishing pad of the polishing unit is larger in diameter than the workpiece,   in the polishing step, the workpiece is polished with the polishing pad while the chuck table that is holding the workpiece and the polishing pad are being oscillated relatively to each other along directions parallel to the surface of the workpiece, and,   in the polishing step, a distance that the chuck table and the polishing pad are oscillated relatively to each other and a central position across which the chuck table and the polishing pad are oscillated relatively to each other are determined, on a basis of the polishing conditions read from the storage section.   
     
     
         4 . The method of processing a workpiece according to  claim 3 , wherein
 the polishing conditions registered in the storage section include a distance between a reference position representing relative positions of the polishing pad and the workpiece at a time when the workpiece has an outer circumferential edge inscribed in an outer circumferential edge of the polishing pad on the processed surface of the workpiece, and the central position across which the chuck table and the polishing pad are oscillated relatively to each other and the distance that the chuck table and the polishing pad are oscillated relatively to each other.