| 摘要 |
PURPOSE:To enable the inspection of a foreign matter with high sensitivity and high precision, by a method wherein a detection signal from each pixel of a parallel output type photoelectric conversion element is subjected to arithmetic processing and it is detected as foreign matter data when the result of said processing is a prescribed value or above. CONSTITUTION:A laser 2 (2a to 2d) irradiates the surface of a sample 1 at a high angle thetaH, while a laser 3 (3a to 3d) irradiates the same at a low angle thetaL. In order to inspect the whole surface of the sample 1, the sample 1 is subjected to an X-Y scan or a spiral scan. Scattered light from the sample 1 is condensed by an objective lens 1 and imaged on the light-sensing surface of a sensor 8 of a parallel output type photoelectric conversion element through a relay lens 7. Next, a detection signal of the sensor 8 is subjected to a foreign matter detection processing for each pixel by using an amplifier circuit and a processing circuit of an arithmetic processing circuit 9. The lasers 2 and 3 are all of S polarization and can be turned ON and OFF individually, and by putting in and out a polarization filter 10 on an optical path, a foreign matter on three kinds of wafers, a specular wafer, a smooth film water and a wafer with a pattern, can be detected. |
