| 摘要 |
PURPOSE:To permit to judge whether failure or deterioration of performance is caused by a comparison/defect decision circuit or not by an apparatus wherein the binary pattern data properly prepared by a computer can be directly supplied to the comparison/defect decision circuit. CONSTITUTION:Corresponding chip patterns in a mask 1 to be inspected are detected using object optical system 2, 2' and pattern detectors 13, 13'. Binary pattern data from binary coding circuits 14, 14' are compared with each other in a comparison/defect decision circuit 9 to carry out the defect decision precessing. At the time of maintenance of the apparatus, change-over switches 11, 11' and 12, 12' are switched to the states indicated by dotted lines, and the binary pattern data from a computer 6 are used for the comparison/defect decision processing so as to make a diagnostic check of the circuit 9. |
