Multi axes motion mechanism enabling multiple optical columns metrology system

Abstract

The system includes a stage configured to support a workpiece and a plurality of optical heads arranged above the stage. Each optical head includes a camera configured to capture a first image of one of a plurality of targets defined on a surface of the workpiece positioned along an optical axis of the camera and a motion mechanism configured to translate the optical head along three axes relative to the stage and rotate the optical head along two axes orthogonal to the optical axis. For each optical head, a processor determines a corrective movement of the optical head based on a misalignment of the optical axis of the camera relative to the target in a first image of the target captured by the camera, and sends instructions to the motion mechanism to move the optical head according to the corrective movement to align the optical axis with the target.

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