A mask stage RS1 and a substrate stage WS1 are synchronously moved,
and a mask stage RS2 and a substrate stage RS2 are synchronously
moved, in a state in which a mask on the mask stage RS1 and a mask on the
mask stage RS2 are irradiated with illumination light beams from illumination
optical systems IOP1, IOP2 respectively. The reaction force on a
base board due to the movement of the stages can be canceled to suppress the vibration
of an exposure apparatus by moving the mask stage RS1 and the mask stage
RS2 in mutually opposite directions. The throughput can be improved by performing
alignment operation on substrate stages WS3, WS4 concurrently with
the exposure operation.
