Nidec Genmark Automation provides the technology to slash the time needed to calibrate a typical semiconductor manufacturing tool from hours to minutes. This Automated Teaching Technology, or Autoteach for short, does not require huge additional capital investments in the form of complex tool modifications and expensive third-party equipment. Autoteach eliminates the subjectivity of manual teaching, ensuring safe and fast manipulation on the production material.
Every time a semiconductor tool is down for repair or scheduled maintenance, the fab loses large amounts of money because of the added repair cost and missed revenue. A considerable amount of this downtime is actually due to robot calibration, a common part of semiconductor tools. Moreover, if this calibration is not performed correctly, the robot can damage or potentially destroy the transferred material, incurring further costs. This is where Autoteach comes in.
How it Works
Autoteach, through its hardware and software resources, translates the absolute XYZ coordinates of the center of the wafer at a pickup location into coordinates
understandable to the robot control system. To get the pickup location coordinates, Autoteach uses the geometry of the given end effector and four through-beam sensors - two horizontal and two vertical. The horizontal sensors define a plane with a known relation to the plane of the wafer at the pickup location, while the vertical ones define the line perpendicular to the wafer plane, drawn through the center of that wafer, and the angle of approach to retrieve or deliver the wafer to that location.
By executing a predefined sequence of motions, the robot's end effector crosses the beams and latches the beam coordinates to the robot coordinate frame. Based on the latched coordinates, and on the known absolute (XYZ) coordinates of the beams, Nidec Genmark's control software calculates the coordinates of the center of the wafer in the robot coordinate space.
Flexible Teaching Methods
Autoteach, through its hardware and software resources, translates the absolute XYZ coordinates of the center of the wafer at a pickup location into coordinates understandable to the robot control system. To get the pickup location coordinates, Autoteach uses the geometry of the given end effector and four through-beam sensors - two horizontal and two vertical. The horizontal sensors define a plane with a known relation to the plane of the wafer at the pickup location, while the vertical ones define the line perpendicular to the wafer plane, drawn through the center of that wafer, and the angle of approach to retrieve or deliver the wafer to that location.
By executing a predefined sequence of motions, the robot's end effector crosses the beams and latches the beam coordinates to the robot coordinate frame. Based on the latched coordinates, and on the known absolute (XYZ) coordinates of the beams, Nidec Genmark's control software calculates the coordinates of the center of the wafer in the robot coordinate space.
Auto-teaching is the process of automatically moving the robot to a configuration, where the end-effector’s position and orientation match those of an ideally placed substrate at the desired location.
This process is facilitated by the use of measurement devices such as substrate aligners or dedicated sensor arrays. When substrate aligners are used, the operator manually places a substrate in the desired position and orientation at the target location (station) to be taught. The robot then picks up the substrate from a default, approximate location—typically determined offline and situated in close proximity to the ideal location.
After picking up the substrate, the robot places it into the aligner, which measures the lateral and angular deviations (offsets) from the desired position. The robot then returns the substrate to the station, applying the corrections provided by the aligner. Typically, one iteration is sufficient, but if higher teaching accuracy is required, a few additional iterations may be performed.
Another approach to teaching utilizes equipment-specific adapters, which aid in accurately positioning or referencing a universal measurement device at the equipment location, while encapsulating the geometric specifics of that location. This allows the same measurement device (tower) to be used across a variety of equipment types.
Once the adapter is placed on the equipment and the measurement tower is mounted on the adapter, the robot performs a set of preprogrammed reference moves, triggering sensors (by breaking light beams) and hardware-latching a series of robot positions—sufficient to derive the position and orientation of the target location. End-effector adapters are also used to unify the shape of a variety of end-effector paddles used for various substrate handling and for geometrical compliance with constraints imposed by the process modules.
A set of adapters allowing automated teaching of a complex material handling system, including 300 mm load ports, a load port for reticle library, track interface, reticle transfer arm, aligner and process modules, is shown.
