| 摘要 |
The present invention addresses the problem of measuring the optical film thickness of an interference film by reflection interference spectroscopy and, when there is a change in the optical film thickness of the interference film, measuring the amount of the change of the optical film thickness. In the measurement of the optical film thickness of an interference film in a laminate in which the interference film is laminated on a substrate by reflection interference spectroscopy, attention is paid to the tendency that as the optical film thickness of the interference film increases, the peak position of the spectral distribution of spectral reflectivity (or the change amount thereof) moves to the long wavelength side, for example, in the order of a curve (b1), a curve (b2), a curve (b3), and a curve (b4) and the number of peaks thereof increases, the relationship between a wavelength at which the optical film thickness of the interference film provides the extreme value of spectral reflectivity (or change amount) in a known laminate and the optical film thickness is created in advance for each of different optical film thicknesses, and the optical film thickness which provides an extreme value at an approximate wavelength is identified by applying, to the abovementioned relationship, a wavelength at which the extreme value of spectral reflectivity (or change amount) in the laminate to be measured obtained by the reflection interference spectroscopy is provided, thereby finding the optical film thickness of the interference film to be measured. |
