| 摘要 |
PROBLEM TO BE SOLVED: To accurately measure the film thickness and the distribution of film thickness without influence of a base pattern by optically obtaining a film thickness of a transparent film according to the frequency and phase of spectral waveform of a detected reflection light. SOLUTION: A light reflected on a wafer passes through an iris focus 10 and a lens 9, and its optical path is changed through a beam splitter 8 and enters a diffraction grating 11, A light splitted spectrally by the diffraction grating 11 is formed on a detector 12, and its spectral intensity distribution 15 can be obtained. The reflection light produces an interference due to a film to be measured, and it has a distribution of spectral intensity corresponding to the structure within a film. The distribution of spectral intensity is subjected to film-thickness calculation processing such as correction and frequency analysis, etc., so as to obtain a film thickness. A light source having a wide wavelength band range such as a tungsten halogen lamp, a xenon lamp, etc., is perferably used as a white light source 6. A laser light with a plurality of different wavelengths may be also used. A CCD two-dimensional sensor or a one- dimensional line sensor may be used as a detector 12. |
