Simulated aerial image of transparent EUVL 45 degree phase defect. The dotted-line white square is the phase defect edge. The dark region corresponds to the area of the image where the intensity was reduced more than 10%. The intensity reduction is localized around the phase edge. The illumination conditions are 13.5 nm wavelength, numerical aperture = 0.25, sigma (partial coherence) = 0.8. The defect size is 40 nm (wafer scale) and assumed pitch is 80 nm (wafer scale).