| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a film-thickness measuring apparatus comprising a function of easily finding the refractive index of a film to be measured. SOLUTION: In the film-thickness measuring method, all maximum wavelengths and all minimum wavelengths due to an interference are found on the basis of a spectral reflectance, a temporary interference order corresponding to a wavelength giving a maximum value and a minimum value is changed, a plurality of film thicknesses are calculated, an interference order in a case where irregularities in a plurality of calculated film thickness values are smallest is used as a true interference order, and the mean value of the film thickness values calculated by the interference order is regarded as a film thickness. The measuring method is provided in such a way that a sample whose film thickness is already known is measured when the refractive index of the film is found, that the interference order is calculated by the method by using the temporary refractive index of the film, that the refractive index of the film at the maximum wavelengths and the minimum wavelengths is calculated in a plurality of points on the basis of the obtained interference order, a maximum wavelength value, a minimum wavelength value and a film thickness value, and that they are substituted by using an approximation expression so as to find the refractive index of the film.</p> |
