The present invention relates to an inspection apparatus and method which include projecting a measurement radiation beam onto a target on a substrate in order to measure the radiation reflected from the target and obtain information related to properties of the substrate. In the present embodiments, the measurement spot, which is the focused beam on the substrate, is larger than the target. Information regarding the radiation reflected from the target is kept and information regarding the radiation reflected from the surface around the target is eliminated. This is done either by having no reflecting (or no specularly reflecting) surfaces around the target or by having known structures around the target, the information from which may be recognized and removed from the total reflected beam. The reflected beam is measured in the pupil plane of the projector such that the information obtained is related to diffraction orders of the reflected beam and profile, critical dimension or overlay of structures on the substrate may be determined.