Patent ID: 7313462

Claim:
In a tool having (a) a plurality of stations for processing microfeature workpieces at known locations relative to a reference frame, (b) cassettes for holding workpieces at known locations relative to the reference frame, (c) an automated workpiece handling system with a robot having a base unit, an arm rotatably coupled to the base unit, and an end-effector rotatably coupled to the arm, and (d) a controller operatively coupled to the automated workpiece handling system, a method of calibrating the robot to the reference frame comprising: providing an initial rotational alignment value indicative of alignment of an arm axis of the arm to a first axis of the reference frame and providing an initial axial position value indicative of a location of the base unit along the first axis; operating the controller to execute a computer operable medium that automatically— (a) aligns the arm axis of the arm with the first axis by contacting a first end of the arm with a rotational reference sensor at a know location relative to the reference frame, recording a first displacement value indicative of a first angle between the arm axis and the first axis, contacting a second point of the arm with the rotational sensor, recording a second displacement value indicative of a second angle between the arm axis and the first axis, and moving the arm according to an arm offset value based upon the first and second displacement values to align the arm axis with the first axis; (b) refines the initial axial position value for the base by rotating the arm to a reference angle relative to the first axis and contacting the arm with an axial sensor at a known location relative to the reference frame to determine an actual location of the base along the first axis; and (c) aligns the end-effector to the first axis by contacting a first side of a workpiece loaded on the end-effector to the rotational reference sensor, recording a first end-effector displacement value, contacting a second side of the workpiece loaded on the end-effector to the rotational reference sensor, recording a second end-effector displacement value, and moving the end-effector according to an end-effector offset value based upon the first and second end-effector displacement values.