| 摘要 |
PURPOSE:To make it possible to automatically detect the relative position to a pattern with good accuracy, by respectively measuring the positional shifts of two sets of marks present at opposed positions with respect to the center of a circle in the specific axial direction crossing a glance direction at right angles. CONSTITUTION:A pattern wherein circular marks 1-4 having an almost same diameter are present at quartered positions on the circumference of a circle having a radius r0 is assumed to be present so that the center of a circle wherein the marks 1-4 are arranged on the x', y'-plane of the x', y', z' rotary coordinates system allowed to take an arbitrary posture by imparting the rotation around each coordinates axis to a x, y, z fixed coordinates system is allowed to coincide with the origin of the rotary coordinates system. The coordinates of the marks 1, 2 in the x', y', z'-rotary coordinates system are respectively set to P1', P2' and converted to the coordinates P1, P2 in the x, y, z-fixed coordinates system to calculate the coordinates values of the coordinates P1, P2. Then, when the positional shifts P31, P42 of the marks 1, 3 and 2, 4 in the axial direction crossing a glance direction at right angles are respectively measured to take the ratio (r) thereof, r=tan theta is formed. The posture angle thetaof the pattern can be detected on the basis of the ratio (r).
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