Mechanical gripper for wafer handling robots

• US 20020009359A1
• Filed: 09/21/2001
• Published: 01/24/2002
• Est. Priority Date: 03/18/1999
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Sundar, Satish
• Granted Patent: US 6,514,033 B2
• Time in Patent Office: Days
• US Class Current: 414/744.5
• CPC Class Codes: B25J 15/0206 comprising articulated grippers
• CPC Class Codes: H01L 21/68707 the wafers being placed on a robot blade, or gripped by a gripper for conveyance

Abstract

The present invention generally provides a robot that can transfer workpieces, such as silicon wafers, at increased speeds and accelerations and decelerations. More particularly, the present invention provides a robot wrist associated with the robot arm for mechanically clamping a workpiece to a workpiece handling member attached to the arm. The workpiece clamp selectively applies sufficient force to hold the workpiece and prevent slippage and damage to the workpiece during rapid rotation and linear movement of the handling member. In one embodiment, a clamp for securing silicon wafers uses two clamp fingers connected to a single flexure member to position and hold the wafer with minimal particle generation and wafer damage. The clamp is designed so that wafers are normally clamped except near full extension of the workpiece handling member to deliver or pick up a wafer.

Claims

1. A clamp wrist for a robot assembly having one or more arms and one or more actuators for driving the one or more arms to handle a workpiece, comprising:

a) a wrist housing pivotally coupled to the one or more arms;

b) at least one clamp finger associated with the wrist housing; and

c) a biasing member coupled to the at least one clamp finger for urging the at least one clamp finger against the workpiece.

2. The clamp wrist of claim 1, further comprising:

a translational member coupled to at least one of the one or more arms; and

a contact pad movably connected to the at least one clamp finger.

3. The clamp wrist of claim 2, wherein the at least one clamp finger is pivotally mounted to the wrist housing;

and the contact pad is positioned to move the at least one clamp finger away from the workpiece when the robot arm reaches a given degree of extension.

4. The clamp wrist of claim 3, further comprising:

a stop member attached to the wrist housing and adapted and positioned to limit the movement of the at least one clamp finger away from the workpiece.

5. The clamp wrist of claim 4, wherein the biasing member is at least one spring.

6. The clamp wrist of claim 5, further comprising:

two clamp fingers mounted in spaced relation to one another and connected to the spring.

7. The clamp wrist of claim 1, further comprising:

a translational member coupled to at least one of the one or more arms;

a flexure member movably connected to the at least one clamp finger;

a contact pad coupled to the flexure member and adapted and positioned to engage the at least one clamp finger and move the at least one clamp finger away from the workpiece when the robot arm reaches a given degree of extension.

8. The clamp wrist of claim 7, further comprising:

two clamp fingers mounted in spaced relation to one another; and

wherein the flexure member is attached to the clamp fingers and adapted to cause the clamp fingers to move apart and away from the workpiece upon engagement of the translational member with the contact pad.

9. The clamp wrist of claim 8, further comprising:

a lever pivotally mounted to the wrist housing and adapted and positioned to engage the contact pad of the flexure member upon engagement of the lever by the translational member.

10. The clamp wrist of claim 1, wherein the at least one clamp finger includes a first clamp finger and a second clamp finger, the clamp fingers located proximate opposing sides of the wafer.

11. A clamping mechanism for securing a workpiece to a workpiece handling member coupled to the distal end of a robot arm, the workpiece handling member comprising a wafer handling blade having a workpiece receiving region and a retaining member at the distal end thereof, comprising:

at least one clamp finger adapted and positioned to contact the edge of the workpiece; and

a biasing member coupled to the at least one clamp finger adapted to urge the at least one clamp finger against the workpiece when the workpiece is positioned on the workpiece receiving region to clamp the workpiece between the at least one clamp finger and the retaining member.

12. The clamping mechanism of claim 11, further comprising a lever arrangement coupled to the at least one clamp finger and adapted to move the finger away from the workpiece when the workpiece handling member and the robot arm are extended.

13. The clamping mechanism of claim 12, wherein the lever arrangement is adapted to be engaged by the relative angular rotation between the robot arm and the workpiece handling member.

14. The clamping mechanism of claim 13, wherein the at least one clamp finger pivotally mounted to the workpiece handling member;

and further comprising a translational member attached to the robot arm positioned and adapted to engage the at least one clamp finger and move the at least one clamp finger away from the workpiece when the robot arm reaches a given degree of extension.

15. The clamping mechanism of claim 14, wherein the lever arrangement further comprises:

a flexure member movably connected to the at least one clamp finger; and

a contact pad coupled to the flexure member for selective engagement with the translational member, and adapted and positioned to engage the at least one clamp finger and move the at least one clamp finger away from the workpiece when the robot arm reaches a given degree of extension.

16. The clamping mechanism of claim 15, wherein the lever arrangement further comprises:

a lever pivotally mounted to the workpiece handling member;

the lever having an end portion;

a contact pad coupled to the lever proximate the end portion for selective mating with the translational member;

the contact pad of the flexure member positioned for selective mating with the lever, whereby engagement of the lever by the translational member causes engagement of the at least one clamp finger to move the clamp finger away from the workpiece when the robot arm reaches a given degree of extension.

17. The clamping mechanism of claim 16 further comprising:

two clamp fingers mounted in spaced relation to one another; and

wherein the flexure member is attached to the clamp fingers and adapted to cause the clamp fingers to move apart upon engagement of the translational member with the contact pad.

18. The clamping mechanism of claim 15, further comprising a stop member attached to the workpiece handling member and adapted and positioned to limit the movement of the at least one clamp finger away from the workpiece.

19. A robot arm assembly, comprising:

a pair of frog-leg type robot arms, each arm having a distal end with a clamp wrist attached thereto; and

the clamp wrist comprising;

a wrist housing pivotally coupled to the robot arm;

at least one clamp finger disposed in the wrist housing; and

a biasing member coupled to the at least one clamp finger adapted to urge the at least one clamp finger against a workpiece.

20. The robot arm assembly of claim 19, further comprising:

a translational member attached to the distal end of the robot arm;

a lever arrangement connected to the at least one clamp finger and adapted and positioned for engagement by the translational member to cause the at least one clamp finger to move away from the workpiece when the robot arm reaches a given degree of extension.

21. The robot arm assembly of claim 20, further comprising:

a stop member attached to the wrist housing and adapted and positioned to limit the movement of the at least one clamp finger away from the workpiece.

22. A robot, comprising:

a pair of first hub members rotatable about a first axis;

a pair of magnetic drives for driving each of the hub members;

a pair of robot arms, each robot arm comprising a first and second strut, the first strut mounted to a hub member;

a translational member disposed on each of the second struts;

a workpiece handling member pivotally attached to the pair of robot arms, the workpiece handling member comprising;

at least one clamp finger;

a biasing member coupled to the at least one clamp finger adapted to urge the at least one clamp finger against a workpiece;

a lever arrangement adapted and positioned to engage the at least one clamp finger in response to engagement of the lever arrangement by the translational member when the attached arm assembly reaches a given degree of extension; and

the lever arrangement is adapted to pull the at least one clamp finger away from the workpiece when the attached arm assembly reaches a given degree of extension.

23. The robot of claim 22, wherein the biasing member is at least one spring.

24. The robot of claim 23, further comprising a lever pivotally mounted to the wrist housing.

25. The robot of claim 24 further comprising:

a stop member attached to the wrist housing and adapted and positioned to limit the movement of the at least one clamp finger away from the workpiece.

26. The robot of claim 25, wherein rotation of the first and second arms in a same direction are converted into one of the two independent motions and rotation of the first and second arms in opposite directions are converted into another of the two independent motions.