Ultra low contact area end effector
View Patent ↗The present invention comprises a vacuum end effector having workpiece supports that work in conjunction with distorted workpiece surfaces. In one embodiment, each workpiece support has the ability to gimbal and conform the workpiece surface in contact with an outer edge of the support. Each workpiece support preferably provides a knife-like contact edge to minimize the contact area between the support and the workpiece while still providing an effective vacuum area to hold the wafer securely on the support. In another embodiment, each workpiece support is replaceable without having to remove the end effector from the robot assembly
1. An end effector for transporting semiconductor workpieces, comprising:
a low-profile body having a proximal end and a distal end, said distal end including a recessed pocket in fluid communication with a vacuum channel passing through a portion of said low-profile body, said recessed pocket having a pivot socket;
a support pad having a central portion with a spherically-shaped bottom surface and a top surface including an elevated contact ridge, said central portion having a vacuum passage extending through, said support pad seated on said pivot socket forming a ball-and-socket joint between said pivot socket and said central portion of said support pad; and
a retaining device removably affixed to a portion of said recessed pocket for limiting the motion of said support pad.
2. The end effector as recited in claim 1 , wherein said recessed pocket includes an opening in a bottom surface of said recessed pocket and said pivot socket is affixed to said bottom surface.
3. The end effector as recited in claim 1 , wherein said support pad comprises a polymer.
4. The end effector as recited in claim 1 , wherein said elevated contact ridge rises above said top surface of said low-profile body such that a wafer seated on said raised contact ridge does not contact said top surface of said low-profile body.
5. An end effector for transporting semiconductor workpieces, comprising:
a low-profile body having a top surface and a distal end forming a first finger and a second finger, said first and second fingers each having a recessed pocket having a bottom surface with an opening to a vacuum passage that travels through a portion of said low-profile body;
a pivot socket located within each one of said recessed areas, each pivot socket having a central opening for allowing gas to travel between said vacuum passage and said recessed pocket;
a wafer support having a top surface with a raised contact edge for contacting a bottom surface of a workpiece and a central portion having a spherically-shaped bottom surface adapted to sit in said pivot socket and form a ball-and-socket joint; and
a retaining device for limiting the motion of said wafer support.
6. The end effector as recited in claim 5 , wherein a bottom surface of a workpiece only contacts said raised contact edge.
7. The end effector as recited in claim 5 , further comprising at least one proximal end workpiece support pad affixed to said low-profile body.
8. The end effector as recited in claim 5 , wherein said raised contact edge comprises a circular geometry.
9. The end effector as recited in claim 5 , wherein said rounded edge comprises a polymer.
10. An end effector for transporting wafers, comprising:
a body having a top surface and a distal end forming a first elongated finger and a second elongated finger, each said finger having a recessed pocket with an opening in a bottom surface of said recessed pocket that is in fluid communication with a vacuum passage traveling through a portion of said body;
a support pad located within each said recessed pocket, said support pad adapted to form a ball-and-socket joint with said opening in said recessed pocket; and
a retaining ring for retaining said support pad within said recessed pocket and limiting the motion of said support pad.
11. The end effector as recited in claim 10 , wherein said support pad includes a central portion having a channel extending through and a top surface extending from said central portion having a raised contact edge.
12. The end effector as recited in claim 11 , wherein said raised contact edge is circular.
13. The end effector as recited in claim 10 , wherein said retaining ring comprises a pad having a top surface affixed to a portion of said support pad and a bottom surface affixed to a portion of said recessed pocket.
14. An end effector for transporting workpieces, comprising:
a body having a vacuum passage extending from a proximal end to a distal end, said distal end forming a first elongated finger and a second elongated finger, said first and second fingers each having a recessed pocket that includes a bottom surface with an opening to provide a passageway between said recessed pocket and said vacuum passage;
a chuck seated in each said recessed pocket, each said chuck having a central body portion with a vacuum channel extending through and a top portion that extends outward from said central body portion, said central body portion adapted to form a ball-and-socket joint with said opening and said top portion adapted to contact a bottom surface of a workpiece seated on said chuck; and
a retaining device located in each said recessed pocket for retaining said chuck within said recessed pocket.
15. The end effector as recited in claim 14 , wherein said retaining device comprises a circular shaped pad having a top surface affixed to said top portion of said chuck and a bottom surface affixed to said bottom surface of said recessed opening.
16. The end effector as recited in claim 14 , wherein said opening in said bottom surface comprises a conical surface.
17. The end effector as recited in claim 14 , wherein said top portion of said chuck includes a circular raised edge.
18. The end effector as recited in claim 17 , wherein said circular raised edge comprises a knife-like edge.
19. The end effector as recited in claim 18 , wherein said circular raised edge comprises a polymer.