INSPECTION APPARATUS, LITHOGRAPHIC APPARATUS, LITHOGRAPHIC PROCESSING CELL AND INSPECTION METHOD

摘要

For angular resolved spectrometry a radiation beam with an illumination profile having four quadrants is used. The first and third quadrants are illuminated whereas the second and fourth quadrants aren't illuminated. The resulting pupil plane is thus also divided into four quadrants with only the zeroth order diffraction pattern appearing in the first and third quadrants and only the first order diffraction pattern appearing in the second and third quadrants.