Patent ID: 7693323

Claim:
A method for inspecting a substrate for defects, the substrate comprising a plurality of elements, the method comprising the steps of: for each element of the substrate, obtaining a detection signal set comprising a plurality of wafer element detection signals generated by a plurality of detectors, and a neighborhood detection signal group comprising a plurality of wafer element neighborhood signal sets, each wafer element neighborhood signal set comprising a plurality of wafer element neighborhood detection signals generated by the plurality of detectors for a wafer element within a neighborhood pattern of one of the substrate elements; calculating for the detection signal set at least one wafer element attribute value; calculating for each neighborhood detection signal set at least one wafer element neighborhood attribute value, to constitute a collection of wafer element neighborhood attribute values; and determining a relationship between the at least one wafer element attribute value, the collection of wafer element neighborhood attribute values, at least one threshold, at least one corresponding reference wafer element attribute value, and corresponding reference wafer element neighborhood attribute values, to indicate a presence of a defect; wherein the at least one wafer element attribute value is calculated by applying one attribute operator on at least two of the wafer element detection signals belonging to the same detection signal set and generated from at least two of the detectors; and wherein the step of obtaining a wafer element detection signal set is preceded by a step of selecting a subset of attribute operations out of a set of attribute operators.