| 摘要 |
<P>PROBLEM TO BE SOLVED: To correct a measured value of an encoder head due to a distortion of a diffraction grating provided to a moving body with high precision. <P>SOLUTION: An X position of a stage WST is measured using encoder heads (X heads) 66<SB>7</SB>and 66<SB>0</SB>having a measurement direction along an X axis, and an X scale 39X<SB>1</SB>provided on the stage WST opposite them. The stage WST is moved along the X axis and a difference between measured values of both the heads 66<SB>7</SB>and 66<SB>0</SB>is found at each of measurement points set at predetermined intervals along the X axis. A distortion of the X scale 39X<SB>1</SB>is found from differences of all the step positions. Similarly, distortions of other scales are measured. Based upon the measured distortions, the measured value of the encoder measuring the position of the stage WST is corrected. <P>COPYRIGHT: (C)2010,JPO&INPIT |
