Composite member its separation method and preparation method of semiconductor substrate by utilization thereof

摘要

In order to separate first and second base substrate without cracking them, and use a damaged base substrate again as a semiconductor substrate to enhance a yield, there is disclosed a preparation method of a semiconductor substrate comprising the steps of separating a composite member formed by bonding the first and second base substrates to each other via an insulating layer into a plurality of members at a separation area formed in a position different from a bonded face to transfer a part of one base substrate onto the other base. A mechanical strength of the separation area is non-uniform along the bonded face in the composite member.