| 摘要 |
PROBLEM TO BE SOLVED: To provide a foreign-matter-diameter determining method in a foreign- matter inspecting apparatus which determines the diameter of a foreign matter accurately in a wide foreign-matter-diameter range. without recource to the dynamic range of a signal processing system. SOLUTION: Analytical curve (analytical curve by a signal intensity) A for finding the diameter of a foreign matter on the basis of a signal intersity outputted from a photodetector, and analytical curve (analytical curve by the number of signals) B for finding the diameter of a foreign matter on the basis of the number of signals are provided. And a larger one out of diameters of a foreign matter obtained respectively by both analytical curves A, B is considered as the diameter of the foreign matter, in a range where analytical curve A for finding the diameter of a foreign matter on the basis of a signal intensity is effective. And a diameter obtained by analytical curve B for finding the diameter of a foreign matter on the basis of the number of signals is considered as the diameter of the foreign matter, in a range where analytical curve A for finding the diameter of a foreign matter on the basis of a signal intensity becomes meaningless.
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