| 摘要 |
PURPOSE:To inspect foreign matter on a semiconductor wafer, etc., automatically by irradiating a plate body with laser light and detecting its reflected light. CONSTITUTION:When the plate body such as a semiconductor wafer is irradiated with laser light, laser light in a fixed direction which is reflected by an etched part A on a fixed angle slanting surface of the semiconductor wafer becomes nearly a horizontal wave, which is polarized in a fixed direction. Reflected light from foreign matter B having numbers of fine slanting surfaces at various angles, on the other hand, contains a vertical wave and is not polarized. Therefore, those reflected light beams are processed by a polarizing plate to detect only the reflected light from the foreign matter, thereby inspecting the foreign matter of the plate body such as a semiconductor wafer automatically. |
