| 摘要 |
<p>PURPOSE:To surely discriminate a foreign matter from a pattern regardless of the direction and form of the pattern formed on a photomask 24, in a foreign matter inspecting device for photomask, and judge the presence of the foreign matter. CONSTITUTION:A foreign matter inspection device has a pair of light detectors 1a, 1b arranged at an optional central angle to the center O of the laser beam scanning area of a photomask 24 and having visual fields including the laser beam scanning area; and a central angle variable device containing a ring gear 6 for changing the central angle theta. The central angle 6 set according to the form of a pattern is varied, the photomask 24 is moved while scanning the laser beam, the directivity of the reflected light from the pattern and a foreign matter is recognized by the light detectors 1a, 1b, and the output signals of the light detectors 1a, 1b are inputted and waveform-processed by a signal processing/judging part 4 to judge the presence of the foreign matter.</p> |
