摘要 |
A mask for evaluating overlay error comprises a plurality of replicate device regions and an overlay mark. The plurality of replicate device regions are disposed uniformly on the mask, wherein each comprises a plurality of device patterns; and a plurality of current layer check patterns are formed adjacent to the plurality of device patterns. The overlay mark is formed on the corner of the mask's peripheral region. In particular, the current layer check patterns are configured to evaluate the pattern offset of a current mask, and the overlay mark and the current layer check patterns are configured to evaluate the overlay error by performing an exposure process using the current mask and a next mask.
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