| 摘要 |
PURPOSE:To enable to accurately position a stage in high resolution and high speed response by controlling the gas pressure from a plurality of gas supply holes of a bearing, thereby positioning the stage. CONSTITUTION:A slide 2 is controlled at the position of an X axis direction by the pressure of gas injected from pads 3A1, 3A2, 3B1, 3B2. When moving leftward, the gas pressures from the pads 3A1, 3A2 are increased, while the gas pressures from the pads 3B1, 3B2 are decreased. Further, the control of the slide 2 in Y direction is performed by similarly altering the gas pressures of the pads 3C1, 3C2, 3D1, 3D2. Then, the intervals to the respective wafers are detected by a photoelectric detecting method at three positions 5 on the surface of the wafer placed on the slide 2. The detector is of telescopic structure. The gas supply pads 3A1 and 3F1, 3E2 and 3F2, 3E3 and 3F3 for positioning in Z direction are respectively automatically controlled independently, thereby varying the clearance DELTAZ. |
