Wafer center finding with kalman filter

• US 8,634,633 B2
• Filed: 09/14/2012
• Issued: 01/21/2014
• Est. Priority Date: 11/10/2003
• Status: Active Grant

• Current Assignee: Brooks Automation Ltd. (United Kingdom) (Azenta, Inc.)
• Original Assignee: Brooks Automation Incorporated (Azenta, Inc.)
• Inventors: Kiley, Christopher C, van der Meulen, Peter, Buzan, Forrest T, Fogel, Paul E.
• Primary Examiner(s): MARIAM, DANIEL G
• Application Number:
  US13/617,333
• Publication Number:
  US 20130085595A1
• Time in Patent Office: 494 Days
• Field of Search: 382/141, 382/145, 382/151, 382/153, 382/288, 348/86, 700/245, 702/150
• US Class Current: 382/141
• CPC Class Codes: B65G 25/02 the carrier or impeller having different forward and return paths of movement, e.g. walking beam conveyors
• CPC Class Codes: B65G 37/00 Combinations of mechanical conveyors of the same kind, or of different kinds, of interest apart from their application in particular machines or use in particular manufacturing processes series of co-operating belt conveyor units B65G15/22; series of co-operating chain conveyor units B65G17/26; sequence control of combined conveyors B65G43/10
• CPC Class Codes: G05B 19/02 electric
• CPC Class Codes: H01L 21/67259 Position monitoring, e.g. misposition detection or presence detection
• CPC Class Codes: H01L 21/67742 Mechanical parts of transfer devices robots in general in B25J
• CPC Class Codes: H01L 21/67748 horizontal transfer of a single workpiece
• CPC Class Codes: H01L 21/68 for positioning, orientation or alignment
• CPC Class Codes: H01L 21/681 using optical controlling means
• CPC Class Codes: Y10S 901/09 Closed loop, sensor feedback controls arm movement
• CPC Class Codes: Y10S 901/47 Optical

Abstract

A device is provided having a robotic arm for handling a wafer, the robotic arm including one or more encoders that provide encoder data identifying a position of one or more components of the robotic arm. The device also having a processor adapted to apply an extended Kalman Filter to the encoder data to estimate a position of the wafer.

Claims

1. A semiconductor handling device comprising:

a vacuum environment including a plurality of robotic handling facilities, each of the robotic handling facilities having a plurality of entrances configured to allow wafer transport to and from an interior of a respective robotic handling facility;

a controller;

a first wafer center finding system including a plurality of sensors connected to the controller and arranged so that no more than two sensors are provided for each entrance of a first one of the plurality of robotic handling facilities, the first wafer center finding system being configured to determine a wafer position using the plurality of sensors and to apply an extended Kalman Filter to estimate the wafer position based upon encoder data from one or more robots; and

a second wafer center finding system including

at least one sensor connected to the controller, where the second wafer center finding system is configured to determine the wafer position within a second one of the plurality of robotic handling facilities by detecting wafer presence, using the at least one sensor, during a robotic movement that includes at least one rotation, or

at least one image contact sensor connected to the controller and configured to capture an image of the wafer within the second one of the plurality of robotic handling facilities while the wafer moves through the second one of the robotic handling facilities, where the second wafer center finding system is configured to determine the wafer position using the contact image sensor.

2. The semiconductor handling device of claim 1, wherein the controller is further configured to determine a predicted sensor transition using the extended Kalman filter.

3. The semiconductor handling device of claim 1, wherein the extended Kalman filter is updated using detected wafer transitions.

4. The semiconductor handling device of claim 1, wherein the controller recalculates the wafer position when new encoder data is received.

5. The semiconductor handling device of claim 1, wherein the wafer position includes a wafer center.

6. The semiconductor handling device of claim 1, wherein the wafer position includes a wafer radius.

7. The semiconductor handling device of claim 1, wherein each of the robotic handling facilities includes a robotic arm having a center axis of rotation within a respective interior, the robotic arm including an end effector for handling wafers, wherein the wafer position is determined with reference to the end effector of the robotic arm or the center axis of the robotic arm.

8. The semiconductor handling device of claim 1, wherein the plurality of entrances include four entrances, seven entrances or eight entrances.

9. The semiconductor handling device of claim 1, wherein the plurality of sensors of the first wafer center finding system and the at least one sensor of the second wafer center finding system includes optical sensors.

10. The semiconductor handling device of claim 1, wherein the plurality of sensors of the first wafer center finding system form an inner and outer array of sensors such that two sensors are disposed at each one of the plurality of entrances, each sensor being configured to detect a presence of a wafer at a predetermined location within the interior.

11. The semiconductor handling device of claim 10, wherein the inner array of sensors is positioned to detect a wafer entering linearly through each one of the plurality of entrances and the outer array of sensors are positioned substantially immediately outside the maximum diameter of the wafer entering linearly through each one of the plurality of entrances.

12. The semiconductor handling device of claim 10, wherein each one of the plurality of entrances shares a sensor from the outer array and one sensor from the inner array with each neighboring one of the plurality of entrances.