Method of grinding wafer

Abstract

A method of grinding a wafer includes a grinding step of grinding, by a grinding wheel, a central region of a wafer held by a holding table, to form a circular recessed part and form a ring-shaped reinforcing part 18 on the outer circumferential side of the circular recessed part. The wafer has such a thickness that the deformation of the wafer in which the circular recessed part 17 is formed is able to be suppressed by the ring-shaped reinforcing part.

What is claimed is: 
     
         1 . A method of grinding a wafer, the method comprising:
 a grinding step of grinding, by a grinding wheel, a central region of the wafer held by a holding table, to form a circular recessed part and form a ring-shaped reinforcing part on an outer circumferential side of the circular recessed part,   wherein the wafer has such a thickness that deformation of the wafer in which the circular recessed part is formed is able to be suppressed by the ring-shaped reinforcing part.   
     
     
         2 . The method of grinding a wafer according to  claim 1 ,
 wherein the wafer has, in a front surface of the wafer, a device region in which a plurality of devices are formed and an outer circumferential surplus region that surrounds the device region, and   the ring-shaped reinforcing part is formed in a region corresponding to the outer circumferential surplus region.   
     
     
         3 . The method of grinding a wafer according to  claim 1 ,
 wherein the thickness of the wafer is equal to or larger than 800 μm.   
     
     
         4 . The method of grinding a wafer according to  claim 1 ,
 wherein the wafer satisfies an expression of the thickness of the wafer≥a diameter of the wafer×0.725/200.   
     
     
         5 . The method of grinding a wafer according to  claim 1 ,
 wherein a diameter of the wafer is equal to or larger than 300 mm.