Patent ID: 8634070
Filing Date: 2014-01-21
Classification: G01N

Abstract:
1. A disk surface inspection apparatus comprising: a stage unit on which a disk of magnetic media is placed as a sample that can be rotated and moved in a direction orthogonal to a center axis of rotation; a first illumination unit for irradiating a front surface on a front side of the sample placed on the stage unit with light; a first regular reflection light detection unit for detecting regular reflection light reflected from the front surface on the front side of the sample irradiated with the light by the first illumination unit; a first low angle scattered light detection unit for detecting scattered light in the vicinity of the regular reflection light reflected from the front surface on the front side of the sample irradiated with the light by the first illumination unit, by separating the scattered light from the regular reflection light; a first high angle scattered light detection unit for detecting scattered light scattered in a direction at a higher angle than the direction of the regular reflection light with respect to a normal direction of the sample, from the sample irradiated with the light by the first illumination unit; a second illumination unit for irradiating a back surface on the back side of the sample placed on the stage unit with light; a second regular reflection light detection unit for detecting regular reflection light reflected from the back surface on the back side of the sample irradiated with the light by the second illumination unit; a second low angle scattered light detection unit for detecting scattered light in the vicinity of the regular reflection light reflected from the back surface on the back side of the sample irradiated with the light by the second illumination unit, by separating the scattered light from the regular reflection light; a second high angle scattered light detection unit for detecting scattered light scattered in the direction at a higher angle than the direction of the regular reflection light reflected from the back surface on the back side of the sample with respect to the normal direction of the sample, from the back surface on the back side of the sample irradiated with the light by the second illumination unit; and a processing unit for detecting defects on the front surface of the sample by processing an output signal from the first regular reflection light detection unit, an output signal from the first low angle scattered light detection unit, and an output signal from the first high angle scattered light detection unit, and detecting defects on the back surface of the sample by processing an output signal from the first regular reflection light detection unit, an output signal from the first low angle scattered light detection unit, and an output signal from the first high angle scattered light detection unit, wherein the regular reflection light detection unit includes a detector having a plurality of detection elements to detect the regular reflection light reflected from the front side of the sample, and wherein the processing unit includes a concave-convex defect determination unit for determining concave and convex features of the defects on the sample by processing the output signal from the detector having the detection elements in the regular reflection light detection unit.