| 摘要 |
The application describes a method for calibrating a wafer transport robot as well as a method and an apparatus for loading/unloading a wafer boat, the wafer boat having a plurality of plates, which are arranged generally parallel to each other in an opposed manner and a plurality of receptacles for receiving the wafers between adjacent plates. The wafer transport robot comprises a wafer gripper which is adapted to insert a wafer into the receptacles between the plates and to remove the wafer therefrom. In one method, the wafer gripper is moved to at least one position, which corresponds approximately to a theoretical loading position, and the spatial position of the wafer gripper is automatically determined in this position. Based on a difference between the determined spatial position of the wafer gripper and the theoretical loading position, at least one correction or compensation parameter for positioning the wafer gripper is determined. In an alternative process, a predetermined point of the wafer gripper, e.g. the center point thereof, is moved to different positions within a theoretical loading zone for a wafer boat by use of a robot coordinate system, and a corresponding spatial position of the wafer gripper is determined in these positions. The corresponding coordinate data of the robot coordinate system are stored in relation to the corresponding determined spatial position of the wafer gripper. For loading/unloading a wafer boat, the wafer boat is measured by use of the same measuring system which was used for determining the spatial position of the wafer gripper for a calibration. The measuring system comprises at least three sensors which are movable along predetermined movement paths, and which are able to measure a distance between the sensor and an edge region of an element entering the measuring range of the sensor along a measuring direction. |
