Patent ID: 6844695

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 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 a length of the at least one beam along the scanning direction being longer than a length of the reflective portion along the scanning direction; and a projection system that projects the pattern onto the object, wherein at least a portion of the projection system is disposed vertically below the mask stage and the counter weight.