As semiconductor technologies continue to decrease in size and the number or metallization layers increase, traditional methods to localize the fault in failing semiconductor circuits such as micro-probing or light emission are severely limited if not impossible to perform. In response to this situation, nano-probe technologies have been developed to overcome this obstacle. In this tutorial, both AFM based and in-situ beam tool based (FIB/SEM) nano-probe technologies will be reviewed. Techniques for proper sample preparation will be presented as well as techniques for the characterization and identification of various semiconductor defects. Case studies for several types of defects will also be presented.