Patent ID: 7907270

Claim:
An inspection apparatus for inspecting a photomask having a pattern formed surface on which light intercepting patterns are formed and a rear surface opposite to the pattern formed surface, so as to detect defects existing on the photomask, the apparatus comprising; an illumination system providing a transmission illumination beam and a reflection illumination beam simultaneously, and directing respectively said transmission and reflection illumination beams onto the photomask from the opposite sides of the photomask, wherein said transmission illumination beam is directed onto the rear surface of the photomask to illuminate a first larger area of the photomask, and the reflection illumination beam is directed onto a pattern formed surface of the photomask to illuminate a second smaller area which overlaps with a part of the first area, so that composite light consisting of transmitted light through the photomask and reflected light by the photomask emanates from the second area, and the transmitted light through the photomask emanates from a third area which is the remaining area of the first area except the second area simultaneously; a detection system comprising a first image sensor for receiving and detecting the composite light emanating from the second area so as to capture a composite image consisting of a transmitted image and a reflected image of the second area of the photomask, and a second image sensor for receiving and detecting the transmitted light emanating from the third area so as to capture the transmitted image of the third area of the photomask; a light directing system directing the composite light emanating from the second area and the transmitted light emanating from the third area onto the detection system; and a processor coupled to the detection system and processing image signals outputted from the detection system to produce data indicative of the defects; wherein said inspection apparatus captures the composite image consisting of the transmitted image and the reflected image of the second area of the photomask and the transmitted image of the third area of the same photomask simultaneously.