| 摘要 |
PURPOSE:To accomplish alignment in a highly precise manner without being influenced by the intensity or the shape of an illumination light by a method wherein the light is received on a mark image using a storage-type sensor in which the positional relation of each element against the reference position is stored, and the center position in the direction of alignment of the mark image on the storage-type sensor is computed from the output of each element of the storage-type sensor. CONSTITUTION:Light is received on a mark image 9, which is obtained by illuminating the region including the mark of the material to be aligned, for an arbitrary period using a storage type sensor having the information on the positional relation of each element against the reference position. The center position P of the alignment direction of the mark image 9 on the storage type sensor 4 is computed from the output of each element of the storage type sensor 14. The distance of alignment direction between the above-mentioned center position P and the reference position is computed, and the material to be aligned is shifted corresponding to the above-mentioned distance. When the intensity of light on the mark image 9a is low, light-receiving time is prolonged. In other words, the time a shutter 15 is opened is made longer, and as a result, an excellent S/N mark-image signal can be obtained. Consequently, even when the magnification of the mark image 9a is increased in order to enhance the resolution of alignment, a sufficient countermeasure can be performed. |
