| 摘要 |
PURPOSE:To accurately position a mask and wafer to prescribed positions, by distributing the set driving quantity of a projecting optical system or object calculated from the output of a measuring means to a coarse moving means and fine moving means in accordance with the current position information of the fine moving means. CONSTITUTION:Responding pressures from air sensor nozzles 12-15 are converted into electrical signals by a voltage converter circuit 22d and the electrical signals are converted into digital data by an A/D converter 22c. The digital data are transmitted to a main body controlling CPU 22a. At the CPU 22a only measured values by effective air sensors are extracted in accordance with the effective/ineffective information of the air sensors stored in a memory 22b in advance and a set driving quantity is instantaneously calculated. The CPU 22a distributes the driving quantity to the driving quanties of a pulse motor 3 and piezo element 5 and inputs the values to a Z-unit driving circuit 22e. At a Z unit 23, the pulse motor 3 and piezo element 5 are drived in accordance with the input values and a wafer 1 is moved in Z direction. |
