Abstract: One or more images of a portion of a wafer with fabricated devices are acquired using an imaging tool. A pattern of repeating features in an input image of a wafer is identified using various methods, such as correlation and clustering of neighboring vectors. A template is generated based on the found pattern of repeating features. The template is aligned with the acquired image to identify target locations. The target locations are then isolated from the original image for performing detailed metrology.

Abstract: One or more images of a device feature are acquired using an imaging tool. A geometrical shape is defined encompassing the relevant pixels of each image, where the geometrical shape is represented in terms of one or more parameters. A cost function is defined whose variables comprise the one or more parameters of the geometrical shape. For each image, numerical optimization is applied to obtain optimal values of the one or more parameters for which the cost function is minimized. The optimal values of the one or more parameters are reported as metrology data pertaining to the device feature.