Abstract: The present invention includes 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 the 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.

Abstract: A substrate inspection method capable of accurately inspecting a substrate is provided. A jig having reference points represented by known coordinates in a three-dimensional world coordinate system is photographed by a camera and coordinates of the reference points in a pixel image coordinate system defined by pixels of an image forming device is determined. The coordinates in the pixel image coordinate system are transformed into those in a camera coordinate system set on the camera, and world-camera coordinate system transformation parameters are calculated. Image data in the pixel image coordinate system obtained by photographing a substrate to be inspected is transformed into image data in a world coordinate system for inspection. The accurate inspection of the substrate to be inspected can be achieved because distortion in the image of the substrate to be inspected in the world coordinate system attributable to the position and attitude of the camera is reduced.

Abstract: The present invention includes 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 the 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.