| 摘要 |
PURPOSE:To display a defect image to a picture surface by modulating the brightness of a CRT by a detecting signal of reflection diffraction beams from the defect section of the pattern and synchronizing beams for a picture with scan light-beams. CONSTITUTION:A sample 4 is scanned by laser beams 1, and outputs from diffraction beam detectors 8, 8' arranged in the directions of (2n+1)X22.5 deg. are added 9, amplified 25 and recognized made correspond to a position on the sample as a defect signal in a signal processing system (an electronic calculator) 17. A positional information is decided by the information transfer for the processing system 17 and a drive control section. The defect signal is given to the CRT 23. Reflected beams 30 are detected 20 and used as a second signal in order to grasp the correlation of a normal pattern and the defect, and diffraction beams from the fringe of the normal pattern are detected by eight detectors 26, 26' arranged in the directions of nX45 deg., and outputs are added 27, amplified 28 and used as a scan brightness modulation signal. Second and third signals are selected 21 and used. According to said constitution, the signal by higher diffraction beams is added to the signal of lower diffraction beams (reflected) while being emphasized and a sharp picture is obtained, and the defect is easily extracted. |
