| 摘要 |
PURPOSE:To ensure the high-accuracy defect test in an economical way by obtaining the point where the tested patterns on two chips are opposing to each other via the correlation method and the electric process and then producing the defect candidate pattern through the space filtering operation to give a test to the pattern. CONSTITUTION:The coherent light of He, Ne or the like given from light source 1 is converted into parallel light 4 through collimator composed of optical lens 2 and 3 to be irradiated on tested pattern 5 such as the IC photo mask or the like. The information light transmitted through pattern 5 is condensed through optical lens 6 to undergo the Fourier conversion, thus obtaining the spectrum distribution corresponding to pattern 5. After this, only the defect information is image-formed on image formation surface 8 via space filter 7 featuring directivity, and the defect candidata is detected through solid state detector 9 such as CCD or the like. This output is then supplied processor 10 via A/D converter 11, and at the same time feeding mechanism 12 is actuated via processor 10. Thus, the output is compared at comparator 14 through memory 13a and 13b while shifting the pattern. |
