| 摘要 |
PROBLEM TO BE SOLVED: To provide a film thickness measuring instrument measuring a film thickness with higher accuracy. SOLUTION: The longer the wavelength of measurement light is, the shorter the period of reflectivity waveforms measured on a measuring object is. Assuming that respective array elements of InGaAs, etc. are disposed at even intervals as to wavelengths, disposition intervals of the respective array elements as to wave numbers are larger as the wave numbers are smaller. Accordingly, in order to accurately sampling the reflectivity waveforms changing with a prescribed period as to the wave numbers, it is necessary that the disposition intervals (wavelength resolutionΔλ) of the respective array elements satisfy a Nyquist's sampling theorem. An upper limit value d<SB>max</SB>of a film thickness measurement range is determined by a condition that this sampling theorem is satisfied. COPYRIGHT: (C)2010,JPO&INPIT |
