In a flatness measurement apparatus, a sensor unit having a flatness-detection sensor is slidable along the linear guide rail. A support system supports the linear guide rail such that the linear guide rail is rotatable in a horizontal plane, whereby a surface of a wafer stage to be measured is scanned all over with the sensor unit having the flatness-detection sensor so as to ensure a flatness measurement of the whole surface of the wafer stage.

 
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< Apparatus for analyzing and sorting biological particles

> Reduction of MEMS mirror edge diffraction in a wavelength selective switch using servo-based multi-axes rotation

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