| 摘要 |
PURPOSE:To position accurately a wafer by selecting an edge signal satisfying a condition such as area without pattern of circumference of mark so as to distinguish it from a signal from other patterns. CONSTITUTION:A wafer 3 having reference patterns (alignment marks) YM1- YM3, thetaM1-thetaM3 for positioning and other patterns (circuit patterns or the like) C1-C3 is aligned to an exposure for patterning of a large scale integrated circuit. A photoelectric microscope for alignment obtaining an edge signal L0 in response to a pattern distribution with a spot light YS from a seeking region including the reference pattern is provided in a seeking direction Y' in crossing with an angle of, e.g., 90 deg. to the reference pattern. A signal satisfying the condition that no circuit pattern or the like exists with respect to the seeking direction Y' and the interval of the reference marks is concident when the reference patterns consist of plural marks is discriminated from the signal L0. The discriminated signal controls the drive of a turntable aligning the wafer 3.
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