A mark for position detection formed on a substrate has a first pattern disposed near the center of the mark and having periodicity in a Y-axis direction, and second patterns respectively disposed near both sides of the first pattern in an X-axis direction and each having periodicity in the X-axis direction....http://www.google.de/patents/US6356343?utm_source=gb-gplus-sharePatent US6356343 - Mark for position detection and mark detecting method and apparatus
