| 摘要 |
PROBLEM TO BE SOLVED: To determine an optimum exposure condition to expose a mass of wafers under this condition by irradiating a photosensitive pattern with an incident light beam, detecting the change of this beam, using signals from light receiving means to obtain the forming condition of the photosensitive pattern. SOLUTION: A beam 305 emitted from an optical source 301 reflects on the surface of a resist formed on a wafer 103 and the surface of the wafer. Combined beam thereof changes such that the phase difference between P- and S-polarizations and amplitude ratio thereof vary according to the birefringences n1 and n2 of the resist on the wafer 103. The beam is detected by a detector 3021 after passing through a rotating quarter wavelength plate 3024 and analyzer 3022. Thus, processing means 3022 obtains sinusoidal electric signals responding to the phase differenceΔand amplitude ratioΨand computes the phase differenceΔand amplitude ratioΨfrom the phase information of sine waves having amplitudes and d-c components corresponding thereto.
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