| 摘要 |
PURPOSE:To prevent the deterioration of workability of a defect inspection by a method wherein a signal detected from a chip is recorded in a memory to be compared with a signal detected from another chip, and the difference signal thereof is determined as a defect. CONSTITUTION:When a mask 9 is transferred in the direction of a broken line arrow mask, a detector system is transferred in the direction of a solid line arrow mark, a lens 1 and a sensor 3 face with the chip A, and detection of a pattern is performed. At this time, no chip exists to face with a lens 2 and a sensor 4. Then, when an automatic change-over switch 12 is operated to connect the output terminal of an amplifier 7 to the memory 11, the detected signal of the chip A is stored in the memory 11. When the mask 9 is transferred by one pitch, the lens 2 and the sensor 4 face with the chip B, while no chip exists to face with the lens 1 and the sensor 3. Then, a change-over switch 13 is operated automatically, and when the input terminal of a comparator 10 is connected to the memory 11, the memory 11 reads out at any time the detected signal of the chip A following the detection to the chip B of the lens 2 and the sensor 4, and the read out signal is applied to the comparator 10. The comparator 10 compares the presently detected signal of the chip B with the detected signal of the chip A, and determines the difference signal thereof as the defect. |
