| 摘要 |
PROBLEM TO BE SOLVED: To accurately measure a film thickness by considering a node in which an interference of a time lag to acquire interference information with a light is weakened. SOLUTION: A method for measuring the film thickness of an active layer 6a for an SOI substrate 6 constituted by interposing an oxide film 6c between the active layer 6a and a support substrate 6b comprises the step of first setting an analyzing wavelength range so as to remove a wavelength to become the 'node' in which the interference is weakened by reflected lights on both surfaces of the film 6b. The method further comprises the steps of dispersing the reflected light by irradiating the layer 6a with the light by a diffraction grating 4a according to respective wavelengths, and then simultaneously acquiring interference information of the light according to the dispersed wavelengths by a CCD array 4b. The method also comprises the step of thereafter calculating the film thickness of the layer 6a by using the interference information in the analyzing wavelength range.
|
