| 摘要 |
<p>A system is provided for determining an eccentricity vector ⊂ which defines the magnitude and direction of an initial placement displaced from a desired location of a centroid O of a right quadrilateral semiconductor wafer (22) which may be clear or opaque. With an initial point for reference desirable established on its peripheral edge (108) for detection by an edge sensor, the wafer is rotated about a point P and a curve defining the profile of the peripheral edge (108) is obtained. The eccentricity vector is computed from the sensed positions of the corners of the wafer and has a magnitude representative of the spatial dislocation of the centroid O relative to the point P and having an orientation Ζ representative of the angle subtended by a first line connecting the point P and the centroid O relative to a second line connecting opposite corners of the wafer. As processing proceeds, the wafer (96) is inserted into an aligner station, then repositioned from an initial position to a desired position, then advanced seriatim into a plurality of processing station (96) while maintaining the desired position previously attained.</p> |
