| 摘要 |
<p>PURPOSE:To detect only the minute white defect part by transmitting and casting only dark-field light or both dark-field light and bright-field light at the same time through a sample having a periodic or nearly periodic pattern region, detecting the transmitted light, emphasizing the image signal, and thereafter performing slice process. CONSTITUTION:In an imaging camera 1, one or more CCD line sensors are arranged in the linear shape. The image of a color filter 2 is focued on the light receiving surface of the line sensor with a lens. The camera 1 picks up only the image of the straight line of the filter 2. The camera 1 is moved in the direction intersecting the linear line sensor at a right angle, and the image of the entire surface of the sample 2 is picked up. A light source 3 performs the transmitting bright-field lighting for the filter 2 in the entire field of view of the camera 1. Light sources 3a and 3b simiarly perform the transmitting dark-field lighting for the filter 2. When the dark-field light is cast on the minute pinhole part of the colored part of the sample, the image of the diffracted light is formed on the line sensor. Thus, S/N is improved, and the minute white defect is detected. The defect detecting rate for the size less than 5mum dia. becomes 50%.</p> |
