| 摘要 |
<p>A digital exposure apparatus for forming a pattern on a topside surface of a substrate has an alignment unit, which detects a position of the substrate from image data obtained through a camera from a reference mark provided on the topside surface of the substrate. The alignment unit further has a Z-direction sensor to measure a fluctuation amount Delta of the topside surface of the substrate from a predetermined focal plane of the camera. Depending upon the measured amount Delta, a set of distortion correction data is selected from or calculated on the basis of previously stored distortion correction data. The image data of the reference mark is corrected with the selected or calculated distortion correction data, so that errors induced by the fluctuation from the focal plane are corrected without adjusting the position of the substrate in the direction of an optical axis of the camera of the alignment unit.</p> |
