flagged as a critical defect requiring costly repair turning to fig8 the alignment of the photomasks 100 200 300 and 500 is shown with the defective metal photomask 400 from fig7 as can be seen relatively small defect 702 will create a conductive metal path between the wells formed on the wafer by means of features 102 and 104 and across the gate that bridges these wells the fact that this defect is critical is easy to ascertain when the location of features on photomasks 100 and 200 are known likewise relatively small defect 706 will substantially prevent the pad formed by feature 506 from contacting with the conductive metal path formed by feature 406 determining that defect 706 is critical is greatly simplified by examining the location of features on photomask 500 it may even happen that a defect occurring on a mask does not connect the critical features while the result of the defect as projected onto a wafer connects the corresponding metal paths furthermore relatively large defect 704 which is relatively close to feature 406 may appear to be a critical defect if only mask 400 is considered as shown in fig8 however defect 704 will not affect the functionality of a die created from the mask set even if defect 704 were in contact with feature 406 a transistor created from the mask set would function normally the fact that relatively large defect 704 is not critical is simple to determine when the mask set is viewed as a whole commercially available photomask inspection systems generally allow the operator to select a single sensitivity level for inspecting.