| 摘要 |
The presence of a workpiece on an end effector of a vacuum robotic handler is detecting using any of a number of non-contact techniques in which some or all of the detection hardware is positioned outside a vacuum chamber that encloses the vacuum robotic handler. Various deployments include laser beam breaking, analysis of radar reflection signals, or analysis of radio frequency identification tag signatures. By providing non-physical couplings between hardware inside and outside of a vacuum environment, integrity of the vacuum is improved. These non-contact techniques are further adapted as described herein to multi-wafer and multi-end effector environments so that independent detection of multiple wafers (e.g., for each end effector) can be performed.
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