Patent ID: 7847927

Claim:
A defect inspection apparatus comprising: a stage that is movable relative to an optical system; an illumination system for illuminating an inspection area on a substrate; an optical element comprising a reflecting mirror that reflects light which emanates from the inspection area on the substrate; a detection optical system arranged behind said optical element, for detecting light from the inspection area in the substrate; a forming optical system which is arranged behind said detection optical system; an image sensor for converting, to a signal, an image which is formed on the image sensor by the detection optical system; and a signal processing system for processing the signal thus converted by the image sensor, and thus detecting defects; wherein: the reflecting mirror is configured to be moved in and out of the light path by a switching mechanism; the reflecting mirror forms a detection optical system for oblique inspection with the reflecting mirror in the light path, and a detection optical system for inspection from above with the reflecting mirror out of the light path; and either of oblique inspection and inspection from above is selectable.