| 摘要 |
The present invention provides a method for determining a location on an object without prealignment and for positioning an object, such as a semiconductor, which has an array of generally perpendicular grid lines on its surface and a plurality of directional features. According to one embodiment the method determines the directions for the grid lines relative to the direction of a reference coordinate system, detects a grid junction and detects a direction of a reference coordinate system, detects a grid junction and detects a direction of one of the plurality of directional features, thereby providing a location of the grid junction in the reference coordinate system. According to an alternative embodiment, the method includes the steps of determining the directions of the grid lines relative to the direction of a reference coordinate system, detecting an asymmetrical directional feature, its orientation with respect to the directions of the grid lines and the distance of the asymmetrical feature from a geometrical center of the surface being known; and detecting a direction of the asymmetrical directional feature, thereby providing a location of the asymmetrical feature in the reference coordinate system. The object is positioned in accordance with the provided location of the grid junction.
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