Patent ID: 7411678
Filing Date: 2008-08-12
Classification: G03F,H01L

Abstract:
1. An alignment apparatus which drives to a target position a stage capable of moving at least in a two-dimensional direction, said apparatus comprising: a first measurement device and a second measurement device which have a function of measuring positions of the stage in one direction from different positions; a switching device which performs a switching operation for switching the first measurement device to the second measurement device; and a controller which sets an initial value for the second position measurement device, which is used after the switching operation, based on the position of the stage finally measured by the first position measurement device before the switching operation, wherein the initial value is obtained by adding the position of the stage finally measured by the first measurement device to a product of a moving velocity of the stage calculated based on a measurement result of said first position measurement device and an execution time from when the first measurement device finally measures the position of the stage before the switching operation to when the second position measurement device starts the measurement of the position of the stage.