Semiconductor device and manufacturing method thereof

Abstract

A thin semiconductor wafer, on which a top surface structure and a bottom surface structure that form a semiconductor chip are formed, is affixed to a supporting substrate. Then, on the wafer, a trench to become a scribing line is formed with a crystal face exposed so as to form a side wall of the trench. On that side wall, an isolation layer for holding a reverse breakdown voltage is formed by ion implantation and low temperature annealing or laser annealing so as to be extended to the top surface side while being in contact with a p collector region as a bottom surface diffused layer. Then, laser dicing is carried out to dice a collector electrode, formed on the p collector region, together with the p collector region.

1 . A method of manufacturing a semiconductor device including the steps of:
 forming a plurality of diffused layers, a first main electrode and a control electrode on a first principal surface side of a semiconductor wafer;   thinning the semiconductor wafer by grinding a second principal surface of the semiconductor wafer;   forming a diffused layer and a second main electrode in contact with the diffused layer on the second principal surface side of the thinned semiconductor wafer;   affixing the second main electrode to a supporting substrate with an adhesive layer in between;   forming a trench reaching the diffused layer on the second principal surface side from the first principal surface side;   forming on the whole area of the surface of the side wall of the trench an isolation layer having the same conductivity type as the diffused layer on the second principal surface side so that the isolation layer is in contact with the diffused layer on the second principal surface side; and   removing the adhesive layer from the thinned semiconductor wafer to produce a plurality of semiconductor chips.   
     
     
         2 . The method of manufacturing a semiconductor device as claimed in  claim 1 , wherein the adhesive layer is formed of at least a thermal foaming tape. 
     
     
         3 . The method of manufacturing a semiconductor device as claimed in  claim 1 , wherein a crystal face of the first principal surface of the thinned semiconductor wafer is a {100} plane, and a crystal face of the surface of the trench is a {111} plane.