| 摘要 |
A method and apparatus for controlling trajectory in a scan and step wafer stepper are described. A control computer controls the motion of a stage by accelerating the stage during an acceleration period. The computer commands the stage to move at a constant velocity during a working period that starts after an end of the acceleration period, so that acceleration of the stage is continuous at the endpoints of the acceleration period. The stage is accelerated and moved so that jerk of the stage is zero and continuous at the endpoints of the acceleration period. The stage may be adapted to support a workpiece. The workpiece may be a semiconductor wafer, in which case the computer causes the wafer to be exposed to radiation during the working period.
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