Surface examining apparatus for detecting the presence of foreign particles on the surface

摘要

An apparatus usable with an object having a surface with a pattern, for examining the state of the surface, includes a projecting system for directing a light beam to the surface of the object, and a collecting system for collecting scattered light from the surface of the object. A projection of the optical axis of the collecting system onto the surface of the object extends in a direction different from a projection onto the surface of the object of a major portion of light diffracted from the pattern. A light-receiving unit receives the scattered light as collected by the collecting system and for producing an output corresponding to the state of the surface of the object.