This paper discusses the basic physics of scanning acoustic microscopy, the counterfeit features it can detect, and how it compares with other screening methods. Unlike traditional optical inspection and IR and X-ray techniques, SAM can identify recycled and remarked chips by exposing ghost markings, fill material differences, delaminations from excessive handling, and popcorn fractures caused by trapped moisture. The paper presents several examples along with detailed images of these telltale signs of semiconductor counterfeiting. It also discusses the potential of developing an automated solution for detecting counterfeits on a large scale.