| 摘要 |
PURPOSE:To hold the degree of parallelism and height of the surface of the wafer regardless of the operation of an XY stage and a theta stage by forming a correction plane to the surface of the wafer to the upper surface of a vertical driving mechanism and moving a wafer base plate together with the XY stage and the theta stage. CONSTITUTION:A wafer 16 is adsorbed and fixed onto the wafer base plate 17, and a pulse motor 21 is driven to correct the displacement of height and an inclination. The plane correcting the displacement of the degree of parallelism and height of the surface of the wafer 16 is formed to a scanning base 15 by the top section of a feed screw mechanism 22. When an alignment mark of a mask pattern and an alignment mark of the wafer 16 are aligned by driving the XY stage 18 and the theta stage 19, the wafer base plate 17 is moved in a horizontal plane by a steel ball 23 while being pushed against the three-point planes of the feed screw mechanism 22 formed onto the scanning base 15 by the resilient force of a coil spring 29 and a leaf spring 20. The wafer can be held in the depth of focus of a projection optics system, and stable resolution can be obtained. |
