| 摘要 |
Two X encoder heads (X heads) and one Y head are mounted on one wafer stage, and an X scale and a Y scale corresponding to these heads are arranged on a surface facing the wafer stage so that the scales connect the exposure area and the alignment area. The wafer stage is made to move back and forth between the exposure area and the alignment area along a path where the X scale and the Y scale are set, while performing position measurement using three encoder heads. In this case, a switching process between XZ interferometer will not be necessary.
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