IMPROVED SIMULTANEOUS MULTI-SPOT INSPECTION AND IMAGING

摘要

A multi-spot inspection system employs an objective (30) for focusing an array of radiation beams (24) to a surface of an object (28) and a second objective (32) having a large numerical aperture for collecting scattered radiation (64) from the array of illuminated spots. The scattered radiation from each illuminated spot is focused to a corresponding optical fiber channel (34) so that information about a scattering may be conveyed to a corresponding detector in a remote detector array (36) for processing. For patterned surface inspection, a cross-shaped filter (90) is rotated along with the surface to reduce the effects of diffraction by Manhattan geometry. A spatial filter (92) in the shape of an annular aperture may also be employed to reduce scattering from patterns such as arrays on the surface.