| 摘要 |
With an optical inspection tool, images of a plurality of patches of a plurality of dies of a reticle are obtained. The patch images are obtained so that each patch image is positioned relative to a same reference position within its respective die as another die- equivalent one of the patch images in each the other ones of the dies. For each patch image, an integrated value is determined for an image characteristic of sub-portions of such patch image. For each patch image, a reference value is determined based on the integrated values of the patch image's corresponding die-equivalent patch images. For each patch image, a difference between that patch image's integrated value and an average or median value of its die-equivalent patch images is determined whereby a significant difference indicates a variance in a pattern characteristic of a patch and an average or median pattern characteristic of its die-equivalent patches. |
