Berkeley Process Control, Inc.

Stephen A Gaudio

Paul Sagues

Tim K Wong

An alignment device for use with a robot for manipulating and aligning a series of semiconductor wafers with respect to an edge fiducial and the center of each wafer is disclosed. The device includes a rotary vacuum chuck for holding a wafer, and an edge detector comprising a light source that extends across the wafer edge as it moves and creates a shadow that falls on a charge coupled device (CCD) below. Output data from the CCD relative to the wafer edge position is processed by a programmable logic circuit and converted to quadrature data which is fed to the logic section of a controller. The controller is programmed to calculate the location of the wafer fiducial relative to the chuck axis and further to calculate the angular and distance offset of the wafer center from the longitudinal axis of the robot arm so that the robot arm can be moved to center the wafer with its fiducial at a preselected location before the wafer is removed from the rotary chuck.

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Berkeley, CA, United States of America

Stephen A Gaudio