Mask inspection method and mask inspection apparatus

An apparatus for detecting a defect of a semiconductor exposure mask, the apparatus comprising:

• an optical system configured to make light of an arbitrary wavelength incident on the mask;
• and
• a controller configured to control the optical system, the controller being configured to execute:
• acquiring background intensities at a plurality of points on the mask from a surface height distribution of the mask;
• acquiring a standard background intensity distribution from the background intensities using a fitting approximation;
• making light of an arbitrary wavelength incident on the mask, and acquiring an image at a position of interest of the mask;
• acquiring background intensity raw data, based on a signal intensity of the acquired image at the position of interest and a mean value of image intensity data in a peripheral area of the position of interest;
• finding a correction coefficient of the signal intensity, based on a ratio of the background intensity raw data to the standard background intensity distribution;
• correcting the signal intensity by multiplying the signal intensity at the position of interest by the correction coefficient;
• and
• determining whether the corrected signal intensity is a predetermined threshold or more.