| 摘要 |
<p>A wafer prealignment method comprises: a high-precision transmission laser sensor calculating, according to circumferential edge data of a wafer and by building a mathematical model for detecting the centroid of the wafer, position coordinates (x̅, y̅) of the centroid, a radial displacement maximum eccentricity vector emax, and an angleθ̅ between a radial displacement maximum eccentric position and the horizontal Y-direction, and actuating the wafer to rotate by the angleθ̅ to make the radial displacement maximum eccentricity vector emax and the horizontal Y-direction in a straight line, so as to accomplish the positioning of the centroid of the wafer; and positioning a notch of the wafer precisely according to the centroid algorithm. The method uses a light transmission sensor to detect an edge of a wafer, and uses a centroid algorithm to determine the positions of a centroid and a notch of the wafer, thereby effectively enhancing the precision of the positioning method, reducing time and space occupied by the prealignment apparatus, and lowering the cost.</p> |
