| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a device used for inspecting a surface of a workpiece, using a light reflected from the surface of the workpiece. SOLUTION: This optical testing device includes (a) a motor for rotating a spindle for rotating the workpiece such as a magnetic disk substrate, (b) an upper test head including a laser for supplying an upper laser beam onto the upper surface of the workpiece, an upper lens for receiving the light reflected from the upper surface, and an upper detector for generating an electric signal expressing the received light, and (c) an under test head including an under laser for supplying a laser beam onto the under surface of the workpiece, an under lens for receiving light reflected from the under surface and an under detector for generating an electric signal expressing the received light. A route of the under laser beam is displaced from a radial direction of the workpiece so as to arrange the under lens more closely to a laser spot, compared with the case where the under laser beam is not displaced. COPYRIGHT: (C)2007,JPO&INPIT
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