摘要 |
<p>Position information of a movable body (WTB) within an XY plane is measured with high accuracy by an encoder system (39X 1 , 39X 2 , 39Y 1 , 39Y 2 , 62B, 62D, 62A, 62C) whose measurement values have favorable short-term stability, without being affected by air fluctuations, and also position information of the movable body in a Z-axis direction orthogonal to the XY plane is measured with high accuracy by a surface position measuring system (74, 76), without being affected by air fluctuations. In this case, since both of the encoder system and the surface position measuring system directly measure the upper surface of the movable body, simple and direct position control of the movable body can be performed.</p> |