| 摘要 |
PURPOSE:To eliminate to the need for stable real image information or a sensitivity adjusting function of the real image information to be compared by including a means to calculate a difference with surface shape information to be compared from interference light intensity and reflected light intensity. CONSTITUTION:A reflection mirror 12 is vibrated by a vibrator 13 according to the surface shape information to be compared on a data disk 14. The interference light intensity, a wavelength of light, the laser light intensity for inspection, the laser light intensity for reference, an optical path difference from the inspection surface, the reference surface and a beam splitter 7 are denoted as I, lambda, I1, I2 and X, respectively, 1 is equal to I1+I2+2X(I1.I2)<1/2>cos(4piX1//lambda). Here, since the reflection mirror 12 for reference is moved according to the surface shape information to be compared, in case a shape of the inspection surface on a sample 1 is equal to the comparison information, I is not changed. In case I is changed, it is detected that a defect exist there. Further, in case the reflectivity of the sample is changed according to a location, the correction can be performed by considering a change of I2 from a photomultiplier 5b.
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