| 摘要 |
PURPOSE:To enable a wafer to be softly chucked without impact force being applied to it and improve reliability of a carrying system, by regulating a speed of ratchet closing operation in accordance with materials of the wafer. CONSTITUTION:When voltage is impressed on a piezo-electric element 11, the element 11 is deformed as shown in an arrow (a) to turn an arm 12 toward the outside, and then the arm overpowers the force of a spring 10 so that a ratchet 9 enters into opening operation. Resultantly this Operation releases a wafer 8. When the voltage impressed on the element 11 is gradually lowered to 0 volt, the element 11 is deformed as shown in an arrow (b) to inversely turn the arm 12 by the force of the spring 10, and then the arm returns to an initial position so that the ratchet 9 enters into closing operation. Resultantly this operation allows the wafer 8 to be chucked with definate chucking force. Patterns of voltage impressed on the element 11 are changed in accordance with materials of the wafer 8. Hence, the wafer 8 can be softly chucked without impact force being applied to it, so that reliability of a carrying system can be improved.
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