| 摘要 |
PURPOSE:To enable the stable automatic inspection of pattern deffects by detecting an accurate brightness and edge position by providing optical systems for obtaining edge information and brightness information separately and optically extracting only a high-order reflected beam from an edge in the former and removing a stray beam in the latter to process the both informations separately. CONSTITUTION:By arraigning a light shielding plate 27 for preventing only a right reflected light 7 on a Fourier transformation plane of an objective 2, only a high-order reflected light 6 reaches a detector 5a. The detector 5a and a sample 1 are relatively scanned to obtain a detection signal 8b. By this optical system, an edge shape can be obtained steadily without an influence of the right reflected light 7. If the S-polarization of light is used for an illuminating light 3a, it is totally reflected by a polarization beam splitter 4a and a stray light 2 from the surface of the objective 2 keeps the S-polarization, so that it does not reach the detector 5a. As the illuminating light for lightening a sample 1a passes through a 1/4 wavelength plate 29 twice, it becomes the P- polarization and reaches the detector 5a through the polarization beam splitter 4a. A detection signal 8c is not influenced by a stray light 27. |
