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How to Compare Rotated and Offset Design Data with DBdiff


Chip level design data can be rotated, reflected (mirrored), or offset prior to tape-out to address reticle alignment or other requirements.

Validating the transformed data with XOR as a sanity check can help to identify any unexpected changes to the mask data prior to delivery to

the foundry. However, traditional XOR validation was typically done between designs with the same orientation. DBdiff and Calibre Fast XOR

enable transformation of the input design data such that transformed data can be automatically compared with the reference design for

accurate sign-off validation. The DBdiff configuration can be used during Calibre FastXOR comparison to validate mask changes with standard

XOR output.


This video demonstrates how to understand the transformation existing between the current and reference designs, and

how to configure DBdiff and FastXOR for comparison.


• Understand how reflection, rotation and offsetting designs impacts XOR

• Determine necessary design transformations for DBdiff compare

• Run DBdiff with design transformation options

• Review transformation requirements for in Calibre FastXOR compare