Method for determining a position of a robot

• US 7,039,501 B2
• Filed: 04/03/2003
• Issued: 05/02/2006
• Est. Priority Date: 07/12/2001
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Hudgens, Jeffrey C., Rice, Michael, Cox, Damon Keith, Freeman, Marvin L., Pencis, Chris Holt, Van Gogh, David A.
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): Marc, McDieunel
• Application Number:
  US10/406,644
• Publication Number:
  US 20040199291A1
• Time in Patent Office: 1,125 Days
• Field of Search: 204/298.35, 204/298.15, 204/298.25, 204/298.26, 204/192.12, 700/218, 700/229, 700/245, 700/253, 700/262, 700/258, 318/640, 318/568.16, 414/806, 414/217, 414/936, 414/937, 414/393
• US Class Current: 700/258
• CPC Class Codes: B25J 9/0009 Constructional details, e.g. manipulator supports, bases
• CPC Class Codes: B25J 9/107 of the froglegs type
• CPC Class Codes: G05B 19/404 characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia G05B19/19, G05B19/41 take precedence
• CPC Class Codes: G05B 2219/37608 Center and diameter of hole, wafer, object
• CPC Class Codes: G05B 2219/39192 Compensate thermal effects, expansion of links
• CPC Class Codes: G05B 2219/49169 Compensation for temperature, bending of tool
• CPC Class Codes: G05B 2219/49207 Compensate thermal displacement using measured distance
• 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: Y10S 414/136 including wafer orienting means
• CPC Class Codes: Y10S 414/137 including means for charging or discharging wafer cassette
• CPC Class Codes: Y10S 414/139 including wafer charging or discharging means for vacuum chamber

Abstract

Generally, a method of determining a position of a robot is provided. In one embodiment, a method of determining a position of a robot comprises acquiring a first set of positional metrics, acquiring a second set of positional metrics and resolving the position of the robot due to thermal expansion using the first set and the second set of positional metrics. Acquiring the first and second set of positional metrics may occur at the same location within a processing system, or may occur at different locations. For example, in another embodiment, the method may comprise acquiring a first set of positional metrics at a first location proximate a processing chamber and acquiring a second set of positional metrics in another location. In another embodiment, substrate center information is corrected using the determined position of the robot.

Claims

1. A method of determining a position of a robot, the method comprising:

recording at least one robot positional attribute in response to a first triggering event;

recording at least one robot positional attribute in response to a second subsequent triggering event; and

resolving the position of the robot due to thermal expansion of the robot using the positional attributes recorded at the first and second triggering events.

2. The method of claim 1, wherein first triggering event further comprises:

causing at least a first sensor to change states.

3. The method of claim 2, wherein the step of causing at the first sensor to change states further comprises:

passing a portion of a robot or a substrate disposed on the robot proximate the first sensor.

4. The method of claim 2, wherein the first sensor is a detection mechanism selected from the group of sensors consisting of optical sensors, proximity sensors, limit switches, reed switches and Hall-effect switches.

5. The method of claim 2, wherein the step of causing the first sensor to change states further comprises:

interrupting a beam of light emitted from the first sensor.

6. The method of claim 5, wherein the step of interrupting the beam further comprise passing the beam through a window disposed in a chamber.

acquiring a second set of robot metrics;

and

resolving a correction of the position of the robot due to thermal expansion of the robot using the robot positional attributes recorded at the first and second triggering events.

7. The method of claim 1, wherein the first triggering event further comprises:

causing a plurality of sensors to change states.

8. The method of claim 7, wherein the step of causing the plurality sensor to change states further comprises:

passing a portion of a robot proximate the first sensor; and

passing a substrate disposed on proximate the first sensor.

9. The method of claim 1, wherein data representing said at least one robot positional attribute recorded in response to the first triggering event is stored in a memory.

10. The method of claim 9, wherein said memory comprises at least one of a buffer memory and a controller memory.

11. The method of claim 1, wherein the step of recording said at least one robot positional attribute in response to the first triggering event further comprises:

causing at least a first sensor disposed proximate a first aperture in a chamber to change states; and

wherein the step of recording said at least one robot positional attribute in response to the second triggering event further comprises;

causing at least the first sensor disposed proximate the first aperture to change states.

12. The method of claim 1, the step of recording said at least one robot positional attribute in response to the first triggering event further comprises:

causing at least a first sensor disposed proximate a first aperture in a chamber to change states; and

wherein the step of recording said at least one robot positional attribute in response to the second triggering event further comprises;

causing at least a second first sensor disposed proximate a second aperture in the chamber to change states.

13. The method of claim 1, wherein the at least one robot positional attribute recorded in response to the first triggering event further comprises one or more data attributes selected from the group consisting of a sensor identification, a time of data collection, position of a first robot motor, position of a second robot motor, velocity of the first robot motor, velocity of the second robot motor, and a state of the sensor.

14. The method of claim 1, wherein the step of resolving the position of the robot due further comprises:

determining a change in length of a linkage extending between the robot and a substrate support blade.

15. The method of claim 14, wherein the step of determining the change in length of the linkage further comprises:

determining an actual reach R_a of the robot;

wherein the linkage comprising a frog-legged linkage having a pair of wings extending from a central body of the robot, the wings coupled by a respective arm to a wrist, each arm coupled to the wrist by a bushing, and the wrist coupled to the substrate support blade; and

wherein R_a is described by;

R_a=R′

(θ

)=A′

cos θ

+√

{square root over (B′

²−

(A′

sin θ

−

C′

)²)}+D

where A′

is the expanded length of a wing linkage;

θ

is the angular position of the wing linkage, B′

is the expanded length of an arm linkage which is coupled to the wing, C′

is half the expanded distance between a bushings on a wrist and D′

is the length of the blade defined from the blade center point to the wrist bushing.

16. The method of claim 1 further comprising:

correcting a stored reference point using the determined reference point.

17. The method of claim 16, wherein the correcting step further comprises rotating a first motor and a second motor coupled to a frog-leg linkage in opposite directions through an angle θ

, wherein θ

is described by;

${\mathrm{\theta <br><br>}}^{\mathrm{\prime <br><br>}}=\arctan <br><br>\left(\frac{C^{\mathrm{\prime <br><br>}}}{R_{\mathrm{CH}}-D}\right)+\arccos <br><br>\left(\frac{{B^{\mathrm{\prime <br><br>}}}^2-{A^{\mathrm{\prime <br><br>}}}^2-\left(\left({C^{\mathrm{\prime <br><br>}}}^2+{\left(R-D\right)}^2\right)\right)}{\sqrt{{C^{\mathrm{\prime <br><br>}}}^2+{\left(R-D\right)}^2-2<br><br>A^{\mathrm{\prime <br><br>}}}}\right)$

where R_CH is the reach at ambient conditions

A′

=A+dA

B′

=B+dB

C′

=C+dC.

18. The method of claim 16 further comprising:

recording at least one robot positional attribute in response to a third triggering event;

resolving a new position of the robot due to thermal expansion of the robot using the positional attributes recorded in response to the second and third triggering events; and

updating the stored reference point using the new position.

19. The method of claim 1 further comprising:

recording at least one robot positional attribute in response to a third triggering event;

resolving a new position of the robot due to thermal expansion of the robot using the positional attributes recorded in response to the second and third triggering events; and

correcting a stored reference point using the determined reference point.

20. The method of claim 1 further comprising:

determining a center position of a substrate disposed on the robot.

21. The method of claim 20 further comprising:

correcting the determined center position by the determined position.

22. The method of claim 1, wherein the robot includes at least one linkage fabricated from ceramic.

23. The method of claim 1, wherein the robot includes at least one linkage fabricated from titanium-doped alumina.

24. A method of determining a position of a robot in a semiconductor processing system having a plurality of ports through which a substrate is passed, at least one process chamber coupled to one of the ports, the method comprising:

determining a center position of the substrate;

adjusting the position by the relative position of the center position;

recording at least one robot positional attribute in response to a first triggering event;

recording at least one robot positional attribute in response to a second subsequent triggering event;

resolving the position of the robot due to thermal expansion of the robot using the positional attributes recorded at the first and second triggering events; and

adjusting the position by the resolved change in position.

25. The method of claim 24, wherein the step of recording the at least one robot positional attribute in response to the first triggering event further comprises:

causing at least a first sensor disposed proximate a first aperture in a chamber to change states; and

wherein the step of recording the at least one robot positional attribute in response to the second subsequent triggering event further comprises;

causing at least the first sensor disposed proximate the first aperture to change states.

26. The method of claim 24, wherein the step of recording at least one robot positional attribute in response to the first subsequent triggering event;

further comprises;

causing at least a first sensor disposed proximate a first aperture in a chamber to change states; and

wherein the step of recording the at least one robot positional attribute in response to the second subsequent triggering event further comprises;

causing at least a second first sensor disposed proximate a second aperture in the chamber to change states.

27. A computer-readable medium having stored thereon a plurality of instructions, the plurality of instructions including instructions which, when executed by a processor, determines a change in position of a robot in a semiconductor processing system comprising:

recording at least one robot positional attribute in response to a first triggering event;

recording at least one robot positional attribute in response to a second subsequent triggering event; and

resolving the position of the robot due to thermal expansion of the robot using the positional attributes recorded at the first and second triggering events.

28. The computer-readable media of claim 27, wherein the step of recording the at least one robot positional attribute in response to the first triggering event further comprises:

causing at least a first sensor to change states.

29. The computer-readable media of claim 28, wherein the step of recording the at least one robot positional attribute in response to the first triggering event further comprises:

passing a portion of a robot or a substrate disposed on the robot proximate the first sensor.

30. The computer-readable media of claim 28, wherein the first sensor is a detection mechanism selected from the group of sensors consisting of optical sensors, proximity sensors, limit switches, reed switches and Hall-effect switches.

31. The computer-readable media of claim 28, wherein the step of causing the first sensor to change states further comprises:

sending a beam from the first sensor; and

reflecting the beam to the first sensor.

32. The computer-readable media of claim 31, wherein the steps of sending and receiving the beam further comprise passing the beam through a window disposed in a chamber.

33. The computer-readable media of claim 27, wherein the step of recording the at least one robot positional attribute in response to the first triggering event further comprises:

causing at plurality of sensors to change states.

34. The computer-readable media of claim 33, wherein the step of causing at the plurality sensor to change states further comprises:

passing a portion of a robot proximate the first sensor; and

passing a substrate disposed on proximate the first sensor.

35. The computer-readable media of claim 27, wherein data representing said least one robot positional attribute recorded in response to the first triggering event is stored in a memory.

36. The computer-readable media of claim 35, wherein said memory comprises at least one of a buffer memory and a controller memory.

37. The computer-readable media of claim 27, wherein the step of recording the at least one robot positional attribute in response to the first triggering event further comprises:

causing at least a first sensor disposed proximate a first aperture in a chamber to change states; and

wherein the step of recording the at least one robot positional attribute in response to the second triggering event further comprises;

causing at least the first sensor disposed proximate the first aperture to change states.

38. The computer-readable media of claim 27, wherein the step of recording the at least one robot positional attribute in response to the first triggering event further comprises:

causing at least a first sensor disposed proximate a first aperture in a chamber to change states; and

wherein the step of recording the at least one robot positional attribute in response to the second triggering event further comprises;

causing at least a second first sensor disposed proximate a second aperture in the chamber to change states.

39. The computer-readable media of claim 27, wherein the at least one robot positional attribute recorded in response to the first triggering event further comprises one or more data attributes selected from the group consisting of a sensor identification, a time of data collection, position of a first robot motor, position of a second robot motor, velocity of the first robot motor, velocity of the second robot motor, and a state of the sensor.

40. The computer-readable media of claim 27, wherein the step of resolving the position of the robot due further comprises:

determining a change in length of a linkage extending between the robot and a substrate support blade.

41. The computer-readable media of claim 40, wherein the step of determining the change in length of the linkage further comprises:

determining an actual reach R_a of the robot;

wherein the linkage comprising a frog-legged linkage having a pair of wings extending from a central body of the robot, the wings coupled by a respective arm to a wrist, each arm coupled to the wrist by a bushing, and the wrist coupled to the substrate support blade; and

wherein R_a is described by;

R_a=R′

(θ

)=A′

cos θ

+√

{square root over (B′

²−

(A′

sin θ

−

C′

)²)}+D

where A′

is the expanded length of a wing linkage;

θ

is the angular position of the wing linkage, B′

is the expanded length of an arm linkage which is coupled to the wing, C′

is half the expanded distance between a bushings on a wrist and D′

is the length of the blade defined from the blade center point to the wrist bushing.

42. The computer-readable media of claim 27 further comprising:

correcting a stored reference point using the determined reference point.

43. The computer-readable media of claim 42, wherein the correcting step further comprises rotating a first motor and a second motor coupled to a frog-leg linkage in opposite directions through an angle θ

, wherein θ

is described by;

${\mathrm{\theta <br><br>}}^{\mathrm{\prime <br><br>}}=\arctan <br><br>\left(\frac{C^{\mathrm{\prime <br><br>}}}{R_{\mathrm{CH}}-D}\right)+\arccos <br><br>\left(\frac{{B^{\mathrm{\prime <br><br>}}}^2-{A^{\mathrm{\prime <br><br>}}}^2-\left(\left({C^{\mathrm{\prime <br><br>}}}^2+{\left(R-D\right)}^2\right)\right)}{\sqrt{{C^{\mathrm{\prime <br><br>}}}^2+{\left(R-D\right)}^2-2<br><br>A^{\mathrm{\prime <br><br>}}}}\right)$

where R_CH is the reach at ambient conditions

A′

=A+dA

B′

=B+dB

C′

=C+dC.

44. The computer-readable media of claim 42 further comprising:

recording at least one robot positional attribute in response to a third triggering event;

resolving a new position of the robot due to thermal expansion of the robot using the positional attributes recorded in response to the second and third triggering events; and

correcting a stored reference point using the determined reference point.

45. The computer-readable media of claim 42 further comprising:

correcting the determined center position by the determined position.

46. The computer-readable media of claim 27 further comprising:

recording at least one robot positional attribute in response to a third triggering event;

resolving a new position of the robot due to thermal expansion of the robot using the positional attributes recorded in response to the second and third triggering events; and

correcting a stored reference point using the determined reference point.

47. The computer-readable media of claim 27 further comprising:

determining a center position of a substrate disposed on the robot.