Method Of Recovering Sem Inspection Induced Mosfets Degradation Before Electrical Characterization

With technology scaling, semiconductor devices have become more prone to damage induced by SEM inspection. In this work, we find that today's widely-used 0.5KeV SEM can also alter the electrical performance of the devices at 20nm technology node. Vts shift with SEM exposure time on nMOS and pMOS has been studied extensively. The cause of the degradation is the positive charge trapped in the gate oxide during SEM radiation. A conventional UV_eraser for EPROM was applied to SEM-damaged devices. The measurement data show that UV exposure can cure most of SEM-induced damage. In the future, if a regular SEM inspection is followed by nanoprobing device characterization, UV curing or another curing methods is required to recover the electric characteristics of the device before nanoprobing.