Modeling of real defect outlines for defect size distribution and yield prediction

For efficient yield, prediction defects are usually modeled by circular disks or squares. A more accurate model is presented. It considers the real outline of physical defects. To utilize this model, only the maximum and the minimum extension of detected defects must be determined. That can be done easily using a checkerboard test structure including a defect localization procedure. The accuracy of the predicted number of defects can be substantially enhanced by modeling real defect outlines with this elliptical model. If the elliptical model of the defect outlines is applied, the defect size distribution implicitly contains information about the physical defect outlines. Hence, for yield prediction the inspection of defect outlines can be omitted