| 摘要 |
PURPOSE:To enable six freedoms of a stage to be controlled with high accuracy and to increase the positioning rigidity, by interposing transmitting means that allows movements other than a feeding direction so that six sets of feeding mechanisms drive independently a stage directly. CONSTITUTION:A base 41 for placing a wafer thereon fixes a pulse motor 46 for constituting a set of X-direction feeding mechanisms, two pulse motors for constituting two sets of Y-direction feeding mechanisms, and three motors 52 for constituting three sets of Z-direction feeding mechanisms. A floating pad 43 of the X-direction feeding apparatus is held on a spherical seat of a nut 44, and would not exert resistance to the vertical movement or backward or forward movement of the stage 42 or the inclination thereof about the X, Y or Z axes, but transmits the corresponding feeding in the X axis. Steel balls 48 and floating pads 49 transmit the feeding in the Z direction to the stage 42, but would not exert resistance to the inclination of the stage 42 in the horizontal plane owing to the presence of the other feeding mechanisms. |
