Patent ID: 8737719
Filing Date: 2014-05-27
Classification: H01L

Abstract:
1. An alignment unit control apparatus comprising: an imaging section configured to control cameras to image a plurality of regions on a surface of a substrate to generate a plurality of images; a region detecting section configured to select a detection region from the plurality of regions based on the plurality of images; an aligning section configured to align the substrate based on an alignment image obtained by imaging a mark of said substrate in the detection region by one of said plurality of cameras; and a brightness summation distribution calculating section configured to calculate a plurality of brightness summation distributions based on the plurality of images, wherein when a first image of the plurality of images and a second image of the plurality of images are different from each other, said region detecting section selects said detection region from a first region shown by the first image and a second region shown by the second image, wherein one of the plurality of brightness summation distributions calculated based on a one of the plurality of images shows a distribution of brightness summations obtained when the image is projected in a projection direction, wherein said region detecting section selects the detection region from the first region and the second region when a first brightness summation distribution calculated based on the first image among the plurality of brightness summation distributions and a second brightness summation distribution calculated based on the second image among the plurality of brightness summation distributions are different from each other, wherein the alignment unit control apparatus further comprises: a ratio change calculating section configured to calculate a ratio change based on the first brightness summation distribution and the second brightness summation distribution, wherein the ratio change at each of positions shows a ratio as a result of dividing a brightness summation at each of positions of the first brightness summation distribution by a brightness summation at the position of the second brightness summation distribution, and wherein when the ratio change has a value which is out of a predetermined range, said region detecting section selects the detection region from the first region and the second region.