A surface position detection device that detects a surface position of a detection target surface (Wa) includes a projection system (1˜6) that projects a light flux onto the detection target surface from a diagonal direction, a light-receiving system (7˜14) that receives a light flux reflected from...http://www.google.com/patents/US6897462?utm_source=gb-gplus-sharePatent US6897462 - Surface position detection device and exposure apparatus and exposure method achieved by utilizing detection device
