Patent ID: 9557169
Date: 2017-01-31
CPC Classifications: G01B,G01N,G03F

Claim:
1. A computer implemented method for tracking a repeated defect in a lithographic photomask that has undergone at least one photomask inspection using a plurality of inspection systems, wherein each photomask inspection has resulted in generating of an inspection report that includes information about defects in the photomask, the computer implemented method comprising: translating a plurality of inspection reports that contain X and Y coordinates of a plurality of defects, wherein each inspection report reports the X and Y coordinates of a defect with respect to a non-standard origin that is specific to the mask inspection system used for generating that particular inspection report, by converting the X and Y coordinates of the non-standard origin into a new set of X and Y coordinates for a common origin, wherein the common origin is the same for the plurality of other inspection reports, wherein translating further includes converting other non-standard fields, such as orientation, into a common set of fields, such as common orientation, that are then populated into a relational database, wherein the common set of fields includes at a minimum horizontal and vertical die count, and horizontal and vertical inter die distance; tagging each inspection report with a unique product code or field that can relate all inspection reports belonging to the same photomask or wafer; matching all defects having coordinates that fall within a tolerance distance of defects flagged in prior inspection records of the same photomask or wafer, that have also undergone a similar translational and tagging step from the relational database, wherein, such matching comprises: identifying defect A from inspection report A performed by inspection system A, identifying a defect B from a subsequent inspection report B performed by inspection system B, wherein defect A and defect B are the same defect that have been reported in inspection report A and inspection report B, wherein inspection system A and inspection system B are two separate types of inspection systems, wherein each inspection system having a defect reporting methodology that is distinct from the other inspection system, wherein such distinction includes each inspection system using a distinct reference point as it coordinate frame origin, and reporting the defect as a repeated defect if defect A and defect B are within a tolerance distance of each other, and enabling overlaying of inspection reports such that any repeating defects can be distinguished from non-repeating defects, and applying additional repair as needed.