METHOD AND EQUIPMENT FOR OPTICAL MEASUREMENT AND OPTICAL MEASURING EQUIPMENT FOR PATTERNED SUBSTRATE

摘要

PROBLEM TO BE SOLVED: To measure the properties of an object to be measured with high sensitivity and accuracy by irradiating the object with a light principally comprising an S polarized component at an incident angle within a specified range and detecting the scattering light by a light receiving means. SOLUTION: An objective glass substrate 12 is irradiated with a coherent light 13 principally comprising an S polarized component from a light source 11 through an optical system 18 at an incident angleθof 45-90 deg.. A part of the irradiating light 13 reflected on the surface serves as an indirect illumination light 19. Scattering light 15 from a defect 14 on the glass substrate 12 is detected by a light receiving means 17 for both the irradiating light 13 and the indirect illumination light 19 in order to obtain the information concerning to the state of the defect 14 on the glass substrate 12. Reflectance is higher constantly under S polarized state than under P polarized state or circularly polarized state and when the incident angleθexceeds about 45 deg., the reflectance is doubled and it is increased drastically when the incident angle exceeds about 70 deg.. Consequently, the indirect illumination light 19 can be utilized effectively regardless of the position of the defect 14 resulting in the enhancement of the measurement accuracy.