Patent ID: 8189185

Claim:
An apparatus for inspecting an object, the apparatus comprising: an illumination system for illuminating the object; an optical detection system for detecting light from the object, the optical detection system including: a high-angle detection system orientated so as to have a high-angle with respect to the object, wherein said high-angle detection system acquires first information related to a luminous intensity of light detected by the high-angle detection system, and a low-angle detection system orientated so as to have a low-angle with respect to the object, wherein said low-angle detection system acquires second information related to a luminous intensity of light detected by the low-angle detection system, and a processing system for classifying each defect of the object based on a relationship between the first information and the second information, using at least one of following conditions: the defect is classified to be a void when the luminous intensity detected by the high-angle detection system is greater than the luminous intensity detected by the low-angle detection system, a defect is classified to be a scratch when the luminous intensity detected by the low-angle detection system is greater than the luminous intensity detected by the high-angle detection system, and a defect is classified to be a particle when the difference between the luminous intensity detected by the low-angle detection system and the luminous intensity detected by the high-angle detection system is not more than a predetermined value.