Operations and Maintenance Manual Control System Description
Version 1.2 - June 2004 5 - 7
ROBOT AND CONTROLLER,
PRE-ALIGNER AND CONTROLLER
The Equipe Technologies robot and controller and pre-aligner and controller packages
incorporate closed loop DC servo motor control and precision mechanics for wafer
handling with full servo control of the radial, theta, and Z axes.
The robot's radial motion extends and retracts the robot arm through a center point;
its theta motion rotates the arm around the center point; its Z motion raises and
lowers the arm.
The pre-aligner consists of a servo driven three-axis mechanism which first rotates the
incoming wafer over a linear array CCD sensor. The CCD sensor, with an associated
uniform light source, provides data to the separate controller box and its internal PC
computer over a parallel input/output link. The computer in the controller then
analyzes this data and computes a vector of offset for the wafer to permit positioning
of the wafer concentrically on the chuck. The pre-aligner is equipped with vacuum
pins around the rotating chuck. The pins can move up and down to lift the wafer and
in an "X" direction to shift the wafer's center position. The vector of offset for the
wafer is then lined up with the directional movement of the pins, which move up to
perform the offset. The pre-aligner then moves the primary flat or notch back over the
sensor for a high resolution scan. It then moves the center of the flat or notch to the
user specified position.
The pre-aligner's radial motion centers the wafer; its theta motion rotates the chuck;
its Z motion raises and lowers the pins.
The PC-based controller permits the robot to make intelligent decisions based upon its
environment utilizing 16 standard external I/O's. The open software structure allows
intelligent macros to be stored in the controller. A "PUT" command is given to the
robot to place a wafer. Likewise, a "GET" command is given to tell the robot to get
the wafer.
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