Edge placement error (EPE)

Edge placement error (EPE) is the difference between the intended and the printed features of an IC layout. It involves patterning of tiny features in precise locations. For example, a feature could be a line, and that line has right and left edges. But in a device, the line and its edges must be precise and placed in exact locations. Then, a contact may land on that line in the device. If these are not precise and exact, that results in misalignment, or an EPE. And if one or more EPE issues crop up in the production flow, the device is subject to shorts or poor yields, which could cause the entire chip to fail.