| 摘要 |
PURPOSE:To control the thickness of a thin film to the desired value when the thin film is deposited on the surface of a substrate by vapor deposition or other method, by radiating rays of light having a specified wavelength related to the thickness and refractive index of the thin film on the thin film and by measuring the quantity of light reflected from the thin film. CONSTITUTION:When a ZnS evaporating source 102 in a vacuum vessel 101 is evaporated by heating with electron beams to deposit a thin ZnS film on a polycarbonate substrate 103 to a thickness d1, a fixed quantity of incident light from a light emitting part 106 above the substrate 103 is radiated and the quantity of light reflected from the surface of the thin film is measured with a light receiving part 107 to obtain a signal of the quantity of reflected light. At this time, light having a wavelength lambdasatisfying relation represented by an equality lambda=4n1d1/m (where n1 is the refractive index of the thin ZnS film and the index measured with an ellipsometer is 2.3) is used as the incident light. For example, light having a wavelength lambda calculated by the equality in which m=2 is used as the incident light, the thickness d1 is calculated by an equality d1=4n1 from the value of reflected light and a shutter 104 is shut at the time when the thickness is increased to the desired value. Thus the thickness of the ZnS film is controlled to the desired value.
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