METHOD AND APPARATUS FOR SELECTING DEFECT OCCURRING ON OR NEAR SURFACE OF FLAT AND SMOOTH SUBSTRATE

PROBLEM TO BE SOLVED: To identify defects such as particles, recesses, scratches or the defects under a surface, etc., generated on or near a flat and smooth surface of a substrate, and determine dimensions of the defects. SOLUTION: In an optical inspecting apparatus, types and dimensions of the defects such as the particles, the recesses or air gaps under the surface occurring on or near the flat and smooth surface of the substrate are specified based on the magnitude S of a plurality of signals generated by lights collected by N different test modes. A database having the relationship of the magnitude S of the signal versus the dimension d of the defect per test mode is referred to for the types of a plurality of virtual defects. The dimension d of the defect corresponding to the magnitude S of the measured signal is specified. An average defect dimension is specified per type of the defect. The magnitude or of the signal corresponding to the defect having the average defect dimension is specified per type of the defect. The type of the defect is specified based on the minimum deviation between the magnitude S1 or SN of the measured signal and the magnitude or of the specified signal.