Method of processing workpiece

Abstract

A method of thinning down a workpiece having a first region and a second region that are layered together includes acquiring a thickness of the first region, thinning down the second region by bringing a processing tool into contact with the workpiece held on a holding table, measuring a thickness of the second region of the workpiece that has been thinned down, adjusting a positional relation between the processing tool and the holding table by referring to a total thickness of the workpiece that includes the thickness of the first region and the thickness of the second region, and thinning down the workpiece by bringing the processing tool into contact with the workpiece held on the holding table.

What is claimed is: 
     
         1 . A method of processing a workpiece having a first region and a second region that are layered together to thin down the workpiece, comprising:
 acquiring a thickness of the first region;   thinning down the second region by bringing a processing tool into contact with the workpiece held on a holding table;   measuring and acquiring a thickness of the second region of the workpiece that has been thinned down;   adjusting a positional relation between the processing tool and the holding table by referring to a total thickness of the workpiece that includes the acquired thickness of the first region and the acquired thickness of the second region; and   thinning down the workpiece by bringing the processing tool into contact with the workpiece held on the holding table after the positional relation between the processing tool and the holding table has been adjusted.   
     
     
         2 . The method of processing a workpiece according to  claim 1 , wherein
 the measuring and acquiring the thickness of the second region includes measuring the thickness of the second region of the workpiece with a thickness measuring instrument that performs thickness measurement while out of contact with the workpiece.   
     
     
         3 . The method of processing a workpiece according to  claim 1 , wherein
 the measuring and acquiring the thickness of the second region includes measuring the thickness of the second region of the workpiece with a thickness measuring instrument that performs thickness measurement using light or ultrasonic waves while out of contact with the workpiece, and   the second region of the workpiece is more transmissive of the light or ultrasonic waves used by the thickness measuring instrument than the first region of the workpiece.   
     
     
         4 . The method of processing a workpiece according to  claim 1 , wherein
 the acquiring the thickness of the first region includes acquiring thicknesses of the first region at a position spaced from a center of the workpiece by a first distance and a position spaced from the center of the workpiece by a second distance different from the first distance, and   the measuring and acquiring the thickness of the second region includes acquiring thicknesses of the second region at the position spaced from the center of the workpiece by the first distance and the position spaced from the center of the workpiece by the second distance.   
     
     
         5 . The method of processing a workpiece according to  claim 1 , wherein
 the measuring and acquiring the thickness of the second region is carried out while the processing tool is not being in contact with the workpiece after the thinning down the second region but before the thinning down the workpiece.   
     
     
         6 . The method of processing a workpiece according to  claim 1 , wherein
 the measuring and acquiring the thickness of the second region is carried out while the thinning down the second region is being carried out or while the processing tool is being in contact with the workpiece after the thinning down the second region.   
     
     
         7 . The method of processing a workpiece according to  claim 1 , wherein
 the acquired thickness of the first region is calculated by subtracting the thickness of the second region from the total thickness of the workpiece.   
     
     
         8 . The method of processing a workpiece according to  claim 1 , wherein
 the acquiring the thickness of the first region is carried out while the workpiece is not being held on the holding table.