| 摘要 |
PURPOSE: To provide a stamper inspection machine by which a stamper for an optical disk can be inspected without a visual inspection difference owing to the difference of an inspector. CONSTITUTION: A stamper which is formed of an Ni electroformed layer is set in such a way that a groove in which information has been recorded becomes the surface and that a face which has been polished precisely becomes the rear surface. It is chucked magnetically on a substrate 2. The surface is irradiated with a light from a light source 7 which radiates light of wavelengths of 500 to 700nm. The depth of the groove on the stamper 6 is at 1000 to 2000Å, and it is close to the wavelengths of the light from the light source 7. As a result, reflected light becomes weak owing to the diffraction of the light, and reflected light which is reflected from an uneven surface defect of the stamper 6 can be observed easily.
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