| 摘要 |
PROBLEM TO BE SOLVED: To easily and exactly determine at least the refractive index of the film on a sample by eliminating the labor of preparing a standard film thickness sample and previously measuring the film thickness or the like. SOLUTION: This optical system receives position information on the light intensity at an arbitrary point on the X-Y plane on the surface of a sample 14 and on the vertical direction (Z direction) of an objective lens 26, stores the light intensity I-objective lens position information Z, selects the two maximal values of the light intensity I from the relation of the light intensity I- objective lens position information Z, determines the light intensity values of a prescribed ratio to the two selected maximum values, for example, ratio of 1/2 of the respective maximum values, determines the half value widths d'Z1 (3 dB), d'Z2 (3 dB)}, of the change in the light intensity I at the light intensity values and calculates the refractive index n2 of the film 14b in accordance with the width of the change in the light intensity I.
|
