Active edge grip rest pad
View Patent ↗The present invention comprises a distal rest pad for supporting a portion of a wafer seated on an end effector. In one embodiment, the rest pad includes a bottom support pad and an edge stop. Each element is mounted separately to the distal end of a support plate. The bottom support pad includes an inclined surface that transitions to a substantially horizontal surface at its distal end. The edge stop has a substantially vertical wafer contact surface that the peripheral edge of a wafer eventually contacts as the wafer is urged towards the distal rest pad. In another embodiment, the bottom support pad comprises an inclined surface. In yet another embodiment, the distal rest pad comprises a single structure. This distal rest pad includes a backstop portion and a bottom support separated by a particle collection groove. The bottom support may include an inclined lead-in surface that transitions into a flat contact surface or only comprise an inclined lead-in surface.
1. A rest pad for supporting a workpiece, the rest pad being mounted to an end effector, comprising:
a support pad having a proximal end, a distal end, and a support surface, said support surface including an inclined surface that transitions to a substantially flat surface at said distal end; and
an edge stop having a wafer contact surface, an edge stop proximal end, and an edge stop distal end, said edge stop being located adjacent to said distal end of said support pad, wherein the support pad and the edge stop are maintained in fixed positions on the rest pad and the wafer contact surface and the support pad remain proximal to each other to restrain the workpiece;
wherein a first imaginary vertical plane is defined to pass through a central axis of said support pad and a second imaginary vertical plane is defined to pass through a central axis of said edge stop, the first and second imaginary vertical planes are offset by an angle so that said first imaginary vertical plane does not intersect said edge stop, said central axis of said support pad extending between said proximal end and said distal end of said support pad and said central axis of said edge stop extending between the edge stop proximal end and the edge stop distal end.
2. The rest pad as recited in claim 1 , wherein said support pad comprises a different material than said edge stop.
3. The rest pad as recited in claim 1 , wherein said wafer contact surface of said edge stop forms an obtuse angle with said substantially flat surface of said support pad.
4. The rest pad as recited in claim 1 , wherein said support pad includes a first protrusion and a second protrusion extending from a bottom surface of said support pad.
5. The rest pad as recited in claim 4 , wherein said first protrusion comprises a different cross-sectional area than the cross-sectional area of said second protrusion.
6. The rest pad as recited in claim 5 , further including a plurality of mounting holes in the end effector, and wherein two of said plurality of mounting holes are adapted to receive said first and second protrusions.
7. The rest pad as recited in claim 1 , further including a first proximal rest pad and a second proximal rest pad mounted to said end effector.
8. The rest pad as recited in claim 1 , wherein said support pad and said edge stop comprise a unitary structure.
9. A rest pad for supporting a workpiece seated on an end effector, comprising:
a support pad having a proximal end and a distal end, a support surface, and a central axis extending from the proximal end to the distal end, said support surface including an inclined surface that transitions to a substantially flat surface at said distal end; and
an edge stop pad having a wafer contact surface, said edge stop pad being located adjacent to said distal end of said support pad so that said central axis of said support pad does not intersect said wafer contact surface,
wherein the support pad and the edge stop are maintained in fixed positions on the rest pad, and the wafer contact surface and the support pad remain proximal to each other to restrain the workpiece.
10. The rest pad as recited in claim 9 , wherein said support pad comprises a different material than said edge stop pad.
11. The rest pad as recited in claim 9 , wherein said wafer contact surface of said edge stop pad forms a 90° angle with said substantially flat surface of said support pad.
12. The rest pad as recited in claim 9 , wherein said wafer contact surface of said edge stop forms an obtuse angle with said substantially flat surface of said support pad.
13. The rest pad as recited in claim 9 , further including a first protrusion and a second protrusion extending from a bottom surface of said support pad.
14. The rest pad as recited inc claim 13 , wherein said first protrusion comprises a different cross-sectional area than the cross-sectional area of said second protrusion.
15. The rest pad as recited in claim 9 , further including a first proximal rest pad and a second proximal rest pad mounted on the end effector.
16. A rest pad for supporting a workpiece, the rest pad being mounted to an end effector, comprising:
a support pad having a proximal end, a distal end, and a support surface, said support surface including an inclined surface that transitions to a substantially flat surface at said distal end and said support pad includes a first protrusion and a second protrusion extending from a bottom surface of said support pad; and
an edge stop having a wafer contact surface, said edge stop being located adjacent to said distal end of said support pad,
wherein an imaginary vertical plane passing through a central axis of said support pad does not intersect said wafer contact surface of said edge stop, said central axis extending between said proximal end and said distal end of said support pad.
17. A rest pad for supporting a workpiece seated on an end effector, comprising:
a support pad having a proximal end and a distal end, a support surface, and a central axis extending from the proximal end to the distal end, said support surface including an inclined surface that transitions to a substantially flat surface at said distal end; and
an edge stop pad having a wafer contact surface, said edge stop pad being located adjacent to said distal end of said support pad so that said central axis of said support pad does not intersect said wafer contact surface,
wherein said support pad includes a first protrusion and a second protrusion extending from a bottom surface of said support pad.