Patent ID: 6559465
Filing Date: 2003-05-06
Classification: G03F

Abstract:
A surface position detecting method wherein an object having a region with a pattern structure formed thereon is relatively scanned relative to surface position detecting means and surface positions of the object at plural detection points in the region are detected by use of the surface position detecting means, said method comprising the steps of:detecting an error related to the detection through the surface position detecting means, with respect to each of the detection points, which error is attributable to a difference in pattern structure at the detection points in the region; detecting the surface positions of the object at the detection points through the surface position detecting means in synchronism with a relative scan of the object and the surface position detecting means, the detection of the surface positions being performed by a sensor, which is arranged to perform the detection in accordance with a predetermined cycle; and determining a timing for the detection by the surface position detecting means in accordance with the relative position of the object and the surface position detecting means during the relative scan, the timing being determined while the detection cycle of the sensor is held synchronized with the relative position of the object and the surface position detecting means.