摘要 |
A method of measuring the topography of a large, thin, non-flat specular substrate in a production environment with minimal movement of a majority of the measurement apparatus. A gimbal-mounted reflecting element is used to steer a short coherence length probe beam such that the probe beam is substantially perpendicular to a local surface of the substrate. The probe beam and the reference beam are combined and the resulting interference pattern used to characterize defects on the local surface.
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