McClure, Qualey & Rodack, LLP
Overlay structure and method of fabricating the same
A method includes: forming overlay structures at scribe lines of a wafer, each side of a die region of the wafer is disposed with at least one of the overlay structures, each of the overlay structures comprises at least one feature and at least one recess disposed above the feature, the feature and the recess are respectively disposed at a first and second layers of the wafer, the recess exposes a portion of the feature vertically aligned with the recess; acquiring an image of the overlay structures; measuring a first dimension and a second dimension of a first portion and a second portion of the recess, respectively; determining an overlay between the first and second layers of an edge region of the wafer based on an average of differences between the first and second dimensions; and modifying a subsequent lithography step to compensate for the overlay.
TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD.
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Chien-Kwen Chi-Chang Te-Chia Cheng-Ming Feng-Pin
Chen Wu Ku Ho Chen