| abstract |
A defect detection system for inspecting objects such as reticles, photomasks, semiconductor wafers, flat panel displays and other patterned objects has two or more stages, whereby the object is examined separately for fine defects, by inspecting a binary level representation of the object, and for ultra fine defects, by inspecting a gray level representation of the object. The system also includes re-inspection apparatus for re-inspection of detected defects, thereby to reduce the false alarm rate, and for classifying the remaining defects by size, area and type. |