| 摘要 |
Described are computer-based methods and apparatuses, including computer program products, for aligning a wafer for fabrication. A first image of a first portion of a wafer is received from a first image capturing device. A second image of a second portion of the wafer is received from a second image capturing device, wherein an image capturing device transform defines a first relationship between the first image capturing device and the second image capturing device. A first fiducial pattern in the first image and a second fiducial pattern in the second image are identified, based on the image capturing device transform, a fiducial transform that defines, based on a specification for the wafer, a second relationship between the first fiducial pattern and the second fiducial pattern, and a threshold value configured to identify low contrast fiducial patterns on wafers. An alignment of the wafer is determined based on the identified first and second fiducial patterns.
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