Process and apparatus for making discrete type substrates by re-slicing a wafer

A process for making a substrate of a semiconductor for use as a discrete element from a wafer including opposed surfaces, edges, and a core portion, comprising the steps of:

• providing said wafer having impurity diffusion layers on both surfaces of said wafer but not containing any impurity diffusion layer in the core portion of said wafer;
• adhering a slice base to a first portion of said edge surface of said unprocessed wafer;
• holding one side of said unprocessed wafer by a vacuum means;
• loading said unprocessed wafer with said slice base into a re-slicing machine provided to rotate a slicing saw at a predetermined speed and at predetermined position;
• re-slicing said unprocessed wafer together with said slice base into two pieces by starting to re-slice said wafer from a second portion of said edge surface which is opposed to said first portion, at substantially the center of the core thickness by said re-slicing machine, by holding an opposed side of said one side of said unprocessed wafer by another vacuum means before finishing re-slicing said slice base;
• whereby a surface of said re-sliced wafer having a plain surface without any impurity diffusion layer, and the other surface having an impurity diffusion layer are formed.