Patent ID: 8553970

Claim:
A method, comprising: analyzing a plurality of wafer defect density maps to identify one or more zones of interest on each of the plurality of wafer defect density maps, each of the plurality of wafer defect density maps indicating defect densities at a plurality of areas on a wafer and each being at a different resolution associated with a different size of the plurality of areas, the plurality of wafer defect density maps being derived from a single defect map of the wafer obtained by an inspection tool and including information concerning the plurality of areas on the wafer, and the zones of interest representing those areas of the plurality of areas on the wafer containing defects with a density above a predetermined number of defects per area; generating spatial signatures in response to relations between the zones of interest and the defect densities within the zones of interest; and performing an inspection process responsive to information obtained from the spatial signatures.