Patent ID: 8040500
Filing Date: 2011-10-18
Classification: G01N,G06K

Abstract:
1. A method of picking up an image of a substrate illuminated with illumination to inspect the substrate for defects, comprising: an illuminance adjustment step of setting an optimum illuminance of the illumination; and a defect inspection step of picking up the image of the substrate illuminated with the illumination at the optimum illuminance, wherein said illuminance adjustment step has: a first step of applying illuminations at different illuminances to a plurality of measurement regions on a front surface of the substrate and picking up an image of each of the measurement regions, while moving the substrate; a second step of making a luminance of the picked up image of each of the measurement regions into a histogram to find a reference luminance where an integral value from a maximum luminance side of the histogram is a predetermined value; and a third step of calculating a correlation between each of the reference luminances and the illuminance, and setting based on the correlation an illuminance at which the reference luminance coincides with a predetermined luminance, as the optimum illuminance in said defect inspection step.