Patent ID: 6969966

Claim:
A scanning exposure method that exposes a pattern of a mask onto an object, the method comprising: moving a mask stage that holds the mask in a scanning direction by a first electromagnetic driver, the first electromagnetic driver having a first portion coupled to the mask stage and a second portion; detecting a position of the mask stage by a position detector that cooperates with a reflective portion of the mask stage, the reflective portion being positioned along the scanning direction; moving a counter weight that comprises a bearing and at least one beam extending along the scanning direction 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 projecting the pattern onto the object by a projection system, at least a portion of the projection system being disposed vertically below the mask stage and the counter weight.