Patent ID: 8855400

Claim:
A method for inspecting a photolithographic mask to identify lithographically significant defects, the method comprising: providing a mask comprising a plurality of printable features and a plurality of non-printable features, the mask configured to achieve lithographic transfer of the printable features onto a substrate using a lithography system; by one or more inspection systems, producing a transmitted image and a reflected image of the mask; constructing a band limited spot image based on the transmitted and reflected images to reduce noise introduced by the one or more inspection systems; restoring the spot image to a mask image to thereby minimize further optical aberrations from the one or more inspection systems in the mask image; using the restored mask image, generating anon-printable feature map for the non-printable features and printable feature map for the printable features; growing the non-printable feature map while preventing encroachment of such non-printable feature map into the printable features based on the printable feature map; and analyzing one or more test images of the mask to detect defects on such mask, wherein a sensitivity level of defect detection is reduced in areas of the one or more test images defined by the non-printable feature map, as compared with areas of the one or more test images that are not defined by the non-printable features map.