Metrology technique that provides true flattening

摘要

An apparatus and method for topographically characterizing a workpiece. The method includes scanning a first surface of a workpiece with a scanning probe at a first resolution to derive a first topographical image, and performing a refining operation on the first topographical image to obtain a true first topographical image. The method also includes scanning, with the scanning probe, a surface of interest of the workpiece, which is a sub-portion of the first surface, at a second resolution that is higher than the first resolution to derive a second topographical image. The second topographical image is scaled down to the first resolution. The method further includes performing a pattern recognition operation to substantially match the scaled-down second topographical image to a corresponding sub-portion of the true first topographical image. The matched sub-portion of the true first topographical image is employed to refine the second topographical image.