Varian Associates, Inc.

Edward D MacIntosh

Richard John Hertel

Eric L Mears

Robert E Jennings

Adrian C Delforge

Akhil Bhargava

Wafer transfer apparatus for horizontal transfer of a wafer between a cassette and an input station of a vacuum processing system includes a wafer transfer arm with a primary section linked to a secondary section so as to move a wafer in a straight line to a location and orientation station and then to the input station. The actual location of the wafer center and the angular orientation of the wafer flat are determined, and the wafer is rotated to a desired angular orientation at the location and orientation station. A solar cell is used to sense actual wafer position by sensing the wafer edge as it is rotated. The required correction and rotation are calculated from the solar cell output. As the wafer is transferred to the input station, correcting displacements are added to the movement so that the wafer is accurately positioned at the input station. A strain gauge is used to reliably sense wafer presence or absence on the transfer arm.

Wafer transfer system

A system for the automated transfer of semiconductor wafers between a cassette and a wafer processing chamber. Included in the system are a cassette conveyor assembly, a wafer transfer assembly and a wafer handling assembly associated with the entrance to the processing chamber. Wafers of any standard size can be accommodated by the system. The cassette conveyor assembly includes a cassette holder which retains and precisely positions two standard plastic cassettes. The cassette holder is positioned by a ball reverser driven by a motor and a mechanical stepper. The wafer transfer assembly includes an elevator blade which vertically raises and lowers wafers to and from the wafer handling assembly. The elevator blade is actuated by a crank driven by a motor and a mechanical stepper. The crank provides a high rate of wafer transfer and a low risk of wafer damage.

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Gloucester, MA, United States of America

Edward D MacIntosh