Abstract: The present invention provides an optical inspection method capable of detecting a finer defect in the surface of a substrate, including the steps of: irradiating a surface of a sample which is rotating and continuously moving in one direction with illumination light which is incident in a direction obliquely to the sample surface; detecting an image of light formed by a forward scattering light around an optical axis of regular-reflection light while excluding the regular-reflection light from the sample surface irradiated with the illumination light; condensing and detecting lateral scattering light which scatters laterally from the sample surface with respect to an incidence direction of the illumination light; and processing a signal obtained by detecting the image of light formed by the forward scattering light and a signal obtained by condensing and detecting the lateral scattering light to extract a defect including a scratch defect.

Abstract: The present invention provides an optical inspection method capable of detecting a finer defect in the surface of a substrate, including the steps of: irradiating a surface of a sample which is rotating and continuously moving in one direction with illumination light which is incident in a direction obliquely to the sample surface; detecting an image of light formed by a forward scattering light around an optical axis of regular-reflection light while excluding the regular-reflection light from the sample surface irradiated with the illumination light; condensing and detecting lateral scattering light which scatters laterally from the sample surface with respect to an incidence direction of the illumination light; and processing a signal obtained by detecting the image of light formed by the forward scattering light and a signal obtained by condensing and detecting the lateral scattering light to extract a defect including a scratch defect.

Abstract: The present invention provides a disk surface defect inspection method including: irradiating a laser beam from an oblique direction onto a disk surface being rotated; detecting intensities of a first light that is scattered with low-angle and a second light that is scattered with high-angle from minute concave and convex defects; determining that a defect is the minute convex defect if a ratio of the intensity of the first light to the intensity of the second light is constant; and determining that a defect is the minute concave defect if the ratio of the intensity of the first light to the intensity of the second light is changed.