Semiconductor wafer and processing method for same

Abstract

A semiconductor wafer which is generally circular, and which has on its face an annular surplus region present in an outer peripheral edge portion of the face, and a circular device region surrounded by the surplus region, the device region having many semiconductor devices disposed therein. A circular concavity is formed in the back of the semiconductor wafer in correspondence with the device region, and the device region is relatively thin, while the surplus region is relatively thick.

1 - 4 . (canceled) 
   
   
       5 . A processing method for a semiconductor wafer which is generally circular, and which has on a face thereof an annular surplus region present in an outer peripheral edge portion of the face, and a circular device region surrounded by the surplus region, the device region having many semiconductor devices disposed therein,
 the processing method comprising forming a circular concavity in a back of the semiconductor wafer in correspondence with the device region to decrease a thickness of the device region.   
   
   
       6 . The processing method according to  claim 5 , further comprising grinding the back of the semiconductor wafer to form the circular concavity. 
   
   
       7 . The processing method according to  claim 6 , further comprising:
 forming the circular concavity by grinding the back of the semiconductor wafer by means of a grinding tool having a plurality of arcuate grinding members arranged in a generally toroidal form, or a toroidal grinding member, the grinding members or the grinding member having an outer diameter somewhat larger than a radius of the circular concavity; and   when grinding the back of the semiconductor wafer by means of the grinding tool,   positioning the grinding tool relative to the semiconductor wafer such that an outer peripheral edge of the grinding members or the grinding member is inscribed in an outer peripheral edge of the device region, and a lower surface of the grinding members or the grinding member straddles a center of the semiconductor wafer,   rotating the semiconductor wafer about a central axis of the semiconductor wafer,   rotating the grinding tool about a central axis of the grinding members or the grinding member, and   moving the grinding tool toward the semiconductor wafer in a direction of the central axis.   
   
   
       8 . The processing method according to  claim 5 , further comprising:
 after forming the circular concavity, cutting the semiconductor wafer along an outer peripheral edge of the device region to remove the surplus region; and   then dicing the device region to separate the semiconductor devices individually.   
   
   
       9 . The processing method according to  claim 5 , further comprising:
 accommodating a circular auxiliary member corresponding to the circular concavity into the circular concavity; and   then dicing the surplus region along with the device region to separate the semiconductor devices individually.