In the peripheral surface defective method of detection of the disk and

摘要

PROBLEM TO BE SOLVED: To provide a method and device for detecting a peripheral surface of a disk capable of detecting highly accurately an outer peripheral defect such as a chuck impression, a flaw or a chip remaining when chucking a disk substrate, almost without detecting foreign matter which is one of defects.;SOLUTION: Regularly reflected light of light incident at an angle in the range of 45°±5° with respect to the surface of a chamfer part is received by a photodetector through a diaphragm, and thereby decline of a level of a light receiving signal of foreign matter generating much scattered light is suppressed small, similarly to a noise, and a level of a light receiving signal of a flaw or the like caused by the chuck impression is lowered greatly, to thereby enlarge a level difference between each detection signal of the foreign matter and the flaw. Then, fluctuation of a signal reference level of the light receiving signal caused by deflection in the vertical direction of a disk outer circumferential surface generated by rotation of the disk is suppressed, or the fluctuation is canceled. Hereby, a detection signal of the outer peripheral defect having a greatly reduced level in the light receiving signal can be acquired easily.;COPYRIGHT: (C)2008,JPO&INPIT