Method of manufacturing wafer

Abstract

A method of manufacturing a wafer from a workpiece that has a first surface, a second surface positioned opposite the first surface, and a side surface joined to outer peripheral edges of the first and second surfaces, the first and second surfaces containing warpage, the method includes grinding the first surface of the workpiece while holding the workpiece on a first holding table such that the second surface faces the first holding table and the first surface is exposed, by gripping and securing the side surface of the workpiece with at least two fixing members of the first holding table without holding the second surface under suction on the first holding table, grinding the second surface of the workpiece, forming a peel-off layer in the workpiece, and peeling off the wafer from the workpiece along the peel-off layer that acts as peel-off initiating points.

What is claimed is: 
     
         1 . A method of manufacturing a wafer from a workpiece that has a first surface, a second surface positioned opposite the first surface, and a side surface joined to an outer peripheral edge of the first surface and an outer peripheral edge of the second surface, the first and second surfaces containing warpage, the method comprising:
 a first grinding step of grinding the first surface of the workpiece while holding the workpiece on a first holding table such that the second surface faces the first holding table and the first surface is exposed, by gripping and securing the side surface of the workpiece with at least two fixing members of the first holding table without holding the second surface under suction on the first holding table;   after the first grinding step, a second grinding step of grinding the second surface of the workpiece;   after the second grinding step, a peel-off layer forming step of forming in the workpiece a peel-off layer that includes modified layers and cracks developed from the modified layers, by positioning a focused spot of a laser beam having a wavelength transmittable through the workpiece in the workpiece at a predetermined depth corresponding to a thickness of the wafer to be manufactured from the workpiece and moving the focused spot and the workpiece relatively to each other in a predetermined direction perpendicular to a thicknesswise direction of the workpiece; and   after the peel-off layer forming step, a peeling step of peeling off the wafer from the workpiece along the peel-off layer that acts as peel-off initiating points.   
     
     
         2 . The method of manufacturing a wafer according to  claim 1 , wherein the second grinding step includes holding the first surface that has been ground in the first grinding step under suction on a holding surface of a second holding table such that the second surface is exposed. 
     
     
         3 . The method of manufacturing a wafer according to  claim 1 , wherein the first surface that is exposed in the first grinding step has protruding warpage, and
 the first grinding step includes reducing the warpage of the first surface by grinding the first surface.   
     
     
         4 . The method of manufacturing a wafer according to  claim 1 , further comprising:
 before the peel-off layer forming step, a planarizing step of reducing surface roughness of one, to be irradiated with the laser beam in the peel-off layer forming step, of the first surface that has been ground in the first grinding step or the second surface that has been ground in the second grinding step.