| 摘要 |
The present invention relates to wafer alignment. A reticle (50) is employed which includes, a design (54), and a first and second set of scribe marks (60, 62, 64, 66). The first and second sets of scribe marks (60, 62, 64, 66) have an associated symmetry relative to the reticle design (54). The design and scribe marks are printed at selected field locations on a surface layer of the wafer (96). The first and second sets of scribe marks as printed (102, 110, 130, 140) at adjacent fields on the surface layer of wafer (96) form a composite set of scribe marks (98a, 98b). The symmetric relationship between the first and second sets of scribe marks results in the composite set of scribe marks substantially negating print errors of the marks due to reticle rotation and/or lens magnification with respect to a geometric reference point of the composite set of scribe marks (98a, 98b). The employment of the composite set of scribe marks, such as to locate a corresponding virtual alignment mark (162, substantially facilitates mitigation of overlay error in wafer alignment.
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