US Patent 9355208 Detecting defects on a wafer

Systems and methods for detecting defects on a wafer are provided. One method includes determining locations of all instances of a weak geometry in a design for a wafer. The locations include random, aperiodic locations. The weak geometry includes one or more features that are more prone to defects than other features in the design. The method also includes scanning the wafer with a wafer inspection system to thereby generate output for the wafer with one or more detectors of the wafer inspection system. In addition, the method includes detecting defects in at least one instance of the weak geometry based on the output generated at two or more instances of the weak geometry in a single die on the wafer.