A simulated wafer image of a physical mask and a defect-free reference image
are
used to generate a severity score for each defect, thereby giving a customer meaningful
information to accurately assess the consequences of using a mask or repairing
that mask. The defect severity score is calculated based on a number of factors
relating to the changes in critical dimensions of the neighbor features to the
defect. A common process window can also be used to provide objective information
regarding defect printability. Certain other aspects of the mask relating to mask
quality, such as line edge roughness and contact corner rounding, can also be quantified
by using the simulated wafer image of the physical mask.
