| 摘要 |
PURPOSE:To reduce random noise of detected signal, by compressing effectively two-dimensional reflected light intensity distribution into one-dimensional light intensity distribution in the pattern position detecting direction. CONSTITUTION:A two-dimensional reflected light intensity distribution developped on a two-dimensional array solid-state pick-up device 36 from the wafer target pattern includes two-dimensional random noise. Therefore, compressing this two-dimensional light intensity distribution in the direction perpendicular to the pattern position detecting direction results in a one-dimensional light intensity distribution caused the random noise to reduce in the pattern position detecting direction. In this way, the two-dimensional reflected light intensity distribution including random noise can be compressed into the one-dimensional light intensity distribution in the pattern position detecting direction, so that the random noise can be reduced extremely to improve the alignment pattern detecting precision.
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