Patent attributes
Methods and systems for diagnosing a semiconductor wafer are provided. A plurality of raw images are captured with a tilt angle from the semiconductor wafer according to graphic data system (GDS) information regarding a layout of a target die, by an inspection apparatus. A first image-based comparison is performed on the plurality of raw images, by a determining circuitry, to obtain a defect image in the plurality of raw images. A second image-based comparison is performed on a reference image and the defect image, so as to classify a defect type of an image difference in the defect image, by the determining circuitry. The number of the plurality of raw images is greater than 2.