| CPC G02B 6/4256 (2013.01) [G02B 6/4214 (2013.01); G02B 6/4296 (2013.01); G06T 7/0004 (2013.01); G06T 2207/30204 (2013.01)] | 20 Claims |

|
1. A structure comprising:
a semiconductor substrate;
a photonic structure; and
a back-end-of-line stack over the semiconductor substrate, the back-end-of-line stack including a first plurality of fill features, a first exclusion area surrounded by the first plurality of fill features, and a first calibration marker in the first exclusion area, the first calibration marker adjacent to the photonic structure, the first calibration marker including a first feature and a second feature adjacent to the first feature, the first feature and the second feature disposed in a row, the first feature having a first predetermined dimension, the second feature has a second predetermined dimension, and the first predetermined dimension of the first feature is larger than the second predetermined dimension of the second feature.
|