EQUIVALENT CIRCULAR DEFECT MODEL OF REAL DEFECT OUTLINES IN THE IC MANUFACTURING PROCESS

For efficient yield prediction and inductive fault analysis of integra ted circuits (IC's), it is usually assumed that defects related to pho tolithography have the shape of circular discs or squares. Real defect s, however, exhibit a great variety of shapes. This paper presents an accurate model to characterize those real defects. The defect outline is used in this model to determine an equivalent circular defect such that the probability that the circular defect causes a fault is the sa me as the probability that the real defect causes a fault, so a norm i s available which can be used to determine the accuracy of a defect mo del, and thus estimate approximately the error that will be aroused in the prediction of fault probability of a pattern by using circular de fect model, Finally, the new model is illustrated with the real defect outlines obtained by optical inspection.