Importance

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Abstract

A method and apparatus for transferring a semiconductor wafer in both a theta axis and a z-axis is provided. The apparatus is able to maintain maximum process and wafer throughput while minimizing the footprint of the processing machine by utilizing the concept of 'vertical integration' to maximize the use of process slots and minimize the machine foot print. The wafer lift apparatus includes a bipolar electrostatic pick-up for engaging the article at an off-center position near an edge thereof. The electrostatic pick-up is positioned near one end of a transfer arm, the other end of the transfer arm being connected to a drive means for rotating the transfer arm and electrostatic pick-up in the theta axis, or vertically moving the transfer arm and electrostatic pick-up in the z-axis. The electrostatic pick-up is preferably connected to a power source by inductive coupling. According to the method of the present invention, the electrostatic pick-up is positioned beneath the wafer at an off-center position, lifted to contact a lower surface of the wafer, and energized to create an attractive force upon the wafer. The wafer is then lifted and rotated to remove the wafer from the end effector. Finally, the wafer is lifted to a pre/post processing plane located above the processing plane.

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First Claim