US Patent 7535563 Systems configured to inspect a specimen

Systems configured to inspect a specimen are provided. One system includes an illumination subsystem configured to illuminate a two-dimensional field of view on the specimen. The system also includes a collection subsystem configured to collect light scattered from the specimen. In addition, the system includes an array of micro-mirrors configured to reflect a two-dimensional pattern of light diffracted from periodic structures on the specimen out of the optical path of the system without reflecting light across an entire dimension of the array out of the optical path. The system further includes a detection subsystem configured to generate output responsive to light reflected by the array into the optical path. The output can be used to detect defects on the specimen. In one embodiment, the system includes an optical element configured to increase the uniformity of the wavefront of the light reflected by the array into the optical path.