| 摘要 |
PURPOSE:To enable the detection of the adhering condition of foreign matters on a substrate by a method wherein beams are scanned on the top surface and the under surface of the substrate in a pellicle equipping condition, light scattered by the foreign matters adhered to the substrate is detected, and detected signals at the positions of the foreign matters are compared. CONSTITUTION:When a laser beam 1 is scanned, light 1a scattered by a foreign matter A is received by a photoelectric element 6 on the top surface side, and at the same time scattered light 1c attenuated by a pellicle 4 is received by a photoelectric element 7 on the under-surface side. Light 1d scattered by a foreign matter B is transmitted again in the pellicle 4 to be detected by the photoelectric element 6, and at the same time, scattered light 1e is received also by the photoelectric element 7 on the under-surface side. When a laser beam 2 is scanned next, scattered lights 2a, 2b are generated to the under-surface side and the top-surface side from the foreign matter A to be received by the photoelectric elements 7, 6, and scattered lights 2c, 2d are generated from the foreign matter B to be received by the photoelectric elements 7, 6. By comparing signals sent from the respective photoelectric elements, the foreign matter adhering surfaces can be judged together with sizes of the foreign matters. |
