A method of assessing damage of a dual damascene structure includes
obtaining a wafer after the wafer has been processed using a dual
damascene process. A first damage-assessment procedure is performed on
the wafer using an optical metrology process to gather damage-assessment
data for a first set of measurements sites on the wafer. For each
measurement site in the first set of measurement sites, the optical
metrology process determines an amount of damage of a damaged area of a
periodic grating in the measurement site. The damage-assessment data
includes the amount of damage determined by the optical metrology
process. A first damage-assessment map is created for the dual damascene
process. The first damage-assessment includes the damage-assessment data
and the locations of the first set of measurement sites on the wafer. One
or more values in the damage-assessment map are compared to
damage-assessment limits established for the dual damascene process to
identify the wafer as a damaged or undamaged wafer.