| 摘要 |
PURPOSE:To simultaneously measure film thickness and a refractive index of a light transmissive film by irradiating an electromagnetic wave to the light transmissive film while varying its incident angle, and measuring the incident angle at which the reflection or transmission intensity takes an extreme value. CONSTITUTION:A monochromatic light from a laser oscillator 1 travels in order of a rotary reflecting mirror 2 lenses 3a, 3b a measuring film 10 a condensing lens, and its light quantity is detected 5. A reflecting point G on the reflecting mirror 2 coincides with a focus of the lens 3a, and parallel rays which have passed through the lens 3a are all placed so as to pass through a focus of the lens 3b. Also, the surface of the film 10 is positioned on the focus of the lens 3b, therefore, the monochromatic light which has been reflected by the reflecting mirror 2 reaches a point H on the film 10, and a measuring position is not shifted. From a CPU7, an incident angle command signal is sent to a galvanometer 8 and the reflecting mirror 2 is oscillated, and the monochromatic light reaches the point H while varying the incident angle. A detected light quantity signal by the detector 5 is sent to the CPU7 and a light quantity variation by the incident angle is analyzed, the incident angle at which the light quantity takes an extreme value is measured continuously, and film thickness and a refractive index of the film 10 are measured.
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