High throughput method of in transit wafer position correction in system using multiple robots

• US 8,060,252 B2
• Filed: 11/30/2007
• Issued: 11/15/2011
• Est. Priority Date: 11/30/2007
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Genetti, Damon, Gage, Chris
• Primary Examiner(s): Trammell; James
• Assistant Examiner(s): Marc; McDieunel
• Application Number:
  US11/998,858
• Publication Number:
  US 20090143911A1
• Time in Patent Office: 1,446 Days
• Field of Search: 701/217, 701/218, 701/245, 701/248, 701/249, 701/259, 701/250, 701/260, 701/261, 701/262, 701/263, 414/217, 414/222.01, 414/416.03, 414/416.08, 414/744.2, 414/744.5, 414/744.6, 414/783, 414/804, 414/93, 414/5, 414/936, 414/937, 414/939, 414/941, 901/2, 901/6, 901/8, 901/9, 901/14, 901/15, 901/30, 901/40, 901/47, 318/568.11, 318/568.12, 318/568.21, 118/719, 118/715, 118/729, 291/1.1, 702/150, 356/614, 204/298.25, 700/217, 700/218, 700/245, 700/248, 700/249, 700/259, 700/250, 700/260, 700/261, 700/262, 700/263
• US Class Current: 700/248
• CPC Class Codes: H01L 21/67196 characterized by the construction of the transfer chamber
• CPC Class Codes: H01L 21/67201 characterized by the construction of the load-lock chamber
• CPC Class Codes: H01L 21/67742 Mechanical parts of transfer devices robots in general in B25J
• CPC Class Codes: H01L 21/68 for positioning, orientation or alignment

Abstract

Methods correcting wafer position error are provided. The methods involve measuring wafer position error on a robot, e.g. a dual side-by-side end effector robot, during transfer to an intermediate station. This measurement data is then used by a second robot to perform wafer pick moves from the intermediate station with corrections to center the wafer. Wafer position correction may be performed at only one location during the transfer process. Also provided are systems and apparatuses for transferring wafers using an intermediate station.

Claims

1. A method of transferring wafers from a first location to a second location, comprising:

extending a dual end effector arm of a first robot to a first location having first and second side-by-side wafers to pick the wafers such that each wafer is supported by an end effector;

retracting the dual end effector arm along a nominal path

transferring the dual end effector arm along a nominal path to an intermediate station;

extending the dual end effector arm along a nominal path to simultaneously place the wafers at the intermediate location;

wherein position information of the wafers relative to the end effectors is measured at some point during the nominal retraction, transfer or extension moves;

sending the position information to a second robot and receiving the position information with the second robot;

picking the first wafer from the intermediate location with a first end effector of the second robot, wherein the position of the first end effector of the second robot during the pick move is adjusted based on the received position information;

picking the second wafer from the intermediate location with a second end effector of the second robot, wherein the position of the second end effector of the second robot during the pick move is adjusted based on the received position information;

transferring the wafers to the second location along a nominal path; and

simultaneously placing the wafers at the second location.

2. The method of claim 1 wherein the dual end effectors of the dual end effector arm of the first robot are fixed with respect to each other.

3. The method of claim 1 wherein the second robot is capable of single wafer transfers and simultaneous transfers of two stacked wafers.

4. The method of claim 1 wherein the first and second end effectors of the second robot are stacked end effectors.

5. The method of claim 1 wherein the first and second end effectors of the second robot are independently articulated end effectors on a single arm.

6. The method of claim 1 wherein the second robot comprises multiple stacked single end effector arms.

7. The method of claim 1 wherein the intermediate location is a loadlock.

8. The method of claim 1 wherein the second location has stacked supports for holding wafers in a stacked configuration.

9. The method of claim 1 wherein the second location is a Front Opening Unified Pod (FOUP) or wafer cassette.

10. The method of claim 1 wherein the intermediate location does not have wafer lift mechanisms.

11. An apparatus for transferring two wafers from a first location to a second location, comprising:

a first location having side-by-side wafer stations;

a first robot having dual side-by-side end effectors with fixed relative positions;

an intermediate station having side-by-side wafer stations;

a second robot; and

a controller for controlling the transfer of the wafers, wherein said controller includes instructions for

extending a dual end effector arm of the first robot to the first location having two side-by-side wafers to pick the wafers such that each wafer is supported by an end effector;

retracting the dual end effector arm along a first nominal path;

transferring the dual end effector arm along a second nominal path to an intermediate station;

extending the dual end effector arm along a third nominal path to place the wafers at the intermediate location, wherein position information of the wafers relative to the end effectors is measured at some point during the nominal retraction, transfer or extension moves;

storing the position information;

picking a first wafer from the intermediate location with a first end effector of the second robot, wherein the position of the first end effector during the pick move is adjusted based on the position information;

picking a second wafer from the intermediate location with a second end effector of the second robot, wherein the position of the second end effector during the pick move is adjusted based on the stored position information;

transferring the wafers to the second location along a fourth nominal path; and

simultaneously placing the wafers at the second location.

12. A method of transferring wafers from a first location to a second location, comprising:

extending an arm of a first robot to a first location having one or more wafers to pick the one or more wafers such that each wafer is supported by an end effector;

retracting the arm along a first nominal path and transferring the arm along a second nominal path to an intermediate station;

extending the arm along a third nominal path to place the one or more wafers at the intermediate location, wherein position information of the one or more wafers relative to its respective end effector is measured at some point during the nominal retraction, transfer or extension moves;

storing the position information and/or sending the position information to a second robot;

picking the one or more wafers from the intermediate location with the second robot wherein picking the one or more wafers comprises adjusting an end effector based on the position information of the wafer being picked such that each wafer is centered on the end effector;

transferring the one or more wafers to the second location along a fourth nominal path; and

placing the one or more wafers at the second location.

13. The method of claim 12 wherein the arm of the first robot has dual side-by-side end effectors that are fixed relative to one another.

14. The method of claim 12 wherein the first location is a loadlock having side-by-side wafer stations.

15. The method of claim 12 wherein extending the arm of the first robot to the first location to pick the one or more wafers comprises simultaneously picking two side-by-side wafers from the first location.

16. The method of claim 12 wherein the second robot has two stacked end effectors.

17. The method of claim 12 wherein picking the one or more wafers from the intermediate location comprises picking two wafers sequentially.

18. The method of claim 12 wherein placing the one or more wafers at the second location comprises simultaneously placing two wafers at the second location.

19. A method of transferring wafers from a first location to a second location, comprising:

measuring wafer position information of one or more wafers handled by a first robot during transfer from the first location to an intermediate location; and

picking the one or more wafers from the intermediate location with a second robot for transfer to the second location, wherein picking the one or more wafers comprises using the measured position information to determine the trajectory of one or more end effectors of the second robot during the pick move.