| 摘要 |
PROBLEM TO BE SOLVED: To surely and quickly detect defects existing on the surface of layered film formed on a wafer, for example and surely and quickly detect small defects even with the roughness on the surface of wafer. SOLUTION: A defect detector for detecting defects on wafer W surface is provided. It has a light source 2 radiating light in a specific frequency zone, a light frequency shifter 6 for converting the light from the source 2 to a plurality of light for inspection and for reference with close frequencies, an object lens 24 in which light for inspection is introduced, condensing light on the wafer W and a plurality of different focus corresponding to each light for inspection is formed, a laser scanner 11 scanning the light for inspection on the wafer W, a light detection part 12 and a co-focus pin hole plate 13 for co-focus detecting the light intensity of the duplicate light of reflection light and reference light, an analyzer 21 as a contrast waveform producing means producing and synthesizing the contrast waveform of scanning direction at each focus position based on the light intensity detected with the light detector 12.
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