INSPECTION DEVICE FOR DEFECT OF REGULAR PATTERN

摘要

PURPOSE:To recognize the presence and kind of defects by comparing detecting signals with reference values by the inspection device of a laser light diffraction pattern space frequency filtering system detecting the defects in a regular pattern by utilizing the defraction phenomenon of light. CONSTITUTION:A detecting signals PS from a unit photodetector is amplified by an amplifier 50 and the signal PS is compared with the lower values ST1, ST2 of a height-type defect by comparators 51, 52 and the output PSC11 and a signal PSC12 converted into length by a counter 54 counting clocks from a gate circuit 53 are fed to an interrupt signal and interrupt address generation circuit through a selection circuit 55. A comparator 57 compares the signal PS with the lower value of a height-type defect and the signal AN1 is fed to the interrupt signal and interrupt address generation circuit through an AND circuit 611. In this way, the defect of a height-type of regular pattern and that of a length-type pattern can precisely be detected.