Abstract: A calibration tool and method for a robot includes a circular transparent plate with at least one reference or "symbolize" line on a planar surface of the tool and a guide groove on an edge of the tool. The size of the tool is equal to the size of a wafer to be processed by the robot. A calibration method using the tool involves placement of the tool on a wafer just before the robot is used to process the wafer, and then driving the robot to catch the tool and move it between the cassette and processing chambers. Because a non-transparent wafer is replaced by the transparent plate, it is easy to adjust the motion of the robot and record information about the motion of the robot, which can then be used to control the motion of the robot.