Patent ID: 6844696

Claim:
A scanning exposure apparatus that exposes a pattern of a mask onto an object, comprising: a mask stage that is movable while holding the mask; a first electromagnetic driver having a first portion coupled to the mask stage and a second portion to move the mask stage in a scanning direction; a position detector having an interferometer system that cooperates with a reflective portion of the mask stage to detect a position of the mask stage, the reflective portion being positioned along the scanning direction; a counter weight having a first bearing, a second bearing, and at least one beam extending along the scanning direction to move in a direction opposite to a movement direction of the mask stage in response to a reaction force generated by a movement of the mask stage by the first electromagnetic driver, the counter weight being heavier than the mask stage, and the at least one beam being coupled to the second portion of the first electromagnetic driver; a base member having a surface extending in the scanning direction and in a non-scanning direction different from the scanning direction to movably support the counter weight via the first bearing; and a guide mounted on the base member and extending along the scanning direction to guide the movement of the counter weight in the scanning direction via the second bearing, a length of the guide along the scanning direction being longer than a length of the reflective portion along the scanning direction.