Patent ID: 7760349
Filing Date: 2010-07-20
Classification: G01N

Abstract:
1. A mask-defect inspecting apparatus, comprising: a plurality of illumination optical systems for illuminating different areas on a mask on which a pattern is formed, one of the plurality of illumination optical systems being a transmission-type illumination optical system to illuminate the mask and the other of the plurality of illumination optical systems being a reflection-type illumination optical system to illuminate the mask; each of the illumination optical systems includes an aperture stop, which are independently adjustable; an objective lens disposed to face the mask; at least a pair of detection optical systems each having a detection sensor to form an image of the pattern and for receiving illumination light from each of the different areas through the objective lens; and an illumination light switch-over mechanism configured to carry out switching over of the illumination light between the transmission-type illumination optical system and the reflection-type illumination optical system; each of the detection optical systems including a mechanism for adjusting an angle of an aperture, wherein each of the mechanisms is capable of adjusting the angle of the aperture independently of the other; each of the detection optical systems including a movable focusing lens to receive light passing through the objective lens; each of the detection optical systems including a focusing control mechanism to control movement of the focusing lens, wherein one of the detection optical systems comprises a transmitted-type detection optical system for receiving light from the area illuminated by the transmitted illumination light and the other of the detection optical systems comprises a reflection-detection optical system for receiving an image from the area illuminated by the reflecting illumination light, wherein a distance of one of the detection sensors from an image plane is different from a distance of another one of the detection sensors from the image plane.