| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface treatment state monitoring device capable of measuring the thickness of a measured layer changing by the minute in real time.SOLUTION: The device comprises: a light source emitting measurement light having wavelength width; an interference optical system having light, which is reflected by upper and lower faces of a measured layer, interfered; a spectroscopic part for performing wavelength dispersion of interference light; and a detection part for detecting light on which the wavelength dispersion is performed for each wavelength. The device further comprises: a storage unit in which a theoretical formula is stored, the formula including the first term which changes depending on a value of ratio between the product of the thickness of the measured layer by a refraction index and the wavelength and which corresponds to the intensity of interference light of light reflected by the upper face of the measured layer and light entering the measured layer and then reflected by the lower face, and a second term which corresponds to the intensity of interference light of the upper face reflected light and light entering the measured layer, reflected again thereinside and then emitted; and a thickness determination unit which determines a thickness of the measured layer so that a plurality of intensity values detected and a theoretical value of the intensity of the interference light match.SELECTED DRAWING: Figure 1 |
