| 摘要 |
A calibration method to calibrate an encoder position measurement system of a stage, the encoder position measurement system including an encoder grid and at least two sensor heads cooperating with the encoder grid, each sensor head providing a sensor head output signal showing a position sensitivity in a horizontal and a vertical direction, the method including a) moving the stage such that the sensor heads are moved with respect to the encoder grid, or vice versa; b) during the moving, measuring the position of the stage with respect to the encoder grid by the two sensor heads; c) determining a vertical position data map from the sensor head output signals of the dual sensor heads; d) calculating a horizontal position data map from the vertical position data map; and e) calibrating the encoder position measurement system applying the calculated horizontal position data map. |
