Substrate centering apparatus and method
A semiconductor substrate centering mechanism includes a plurality of substrate support pins, each pin having a top surface. The top surfaces of the pins define a plane in which the substrate is supported. Each pin has a tab mounted eccentrically at the top surface of the pin. The tabs extend upwardly relative to the top surfaces of the pins. The centering mechanism further includes a pin rotation mechanism adapted to rotate each pin. The pin rotation mechanism rotates the pins between a first position in which the tabs define an envelope that is larger than a circumference of the substrate and a second position in which the tabs define a centered position for the substrate. A telescoping arrangement of nesting shield segments may also be provided for each pin to prevent processing fluid from reaching a shaft of the pin. In one aspect the centering mechanism is coupled to a substrate support of a substrate processing location, and thus allows a substrate to be centered as it is lowered to the processing location.
1. An apparatus for supporting and centering a substrate, comprising:
a substrate chuck having:
a plurality of pins, each pin having a top surface and a longitudinal axis of rotation, the top surfaces of the pins defining a plane in which the substrate is supported, each pin having a tab mounted eccentrically with respect to the pin's longitudinal axis of rotation at the top surface of the pin and extending upwardly relative to the top surface of the pin; and
a pin rotation mechanism adapted to rotate each pin about a longitudinal axis of the respective pin, the pin rotation mechanism rotating the pins between a first position in which the tabs define an envelope that is larger than a circumference of the substrate and a second position in which the tabs define a centered position for the substrate.
2. The apparatus of claim 1 , further comprising a fluid dispenser positioned relative to the substrate chuck so as to direct fluid to a substrate supported thereby;
wherein the fluid dispenser is positioned relative to the substrate chuck so as to direct fluid toward an edge of a substrate supported thereon.
3. The apparatus of claim 1 wherein the pin rotation mechanism includes:
a plurality of pin rotation mechanisms each mounted concentrically with respect to one of the pins, and
a central transmission mechanism adapted to simultaneously transfer rotary motion to each of the plurality of pins.
4. The apparatus of claim 3 wherein the substrate chuck has a central axis of rotation, and the central transmission mechanism is mounted on the substrate chuck's central axis of rotation.
5. The apparatus of claim 3 wherein the plurality of pin rotation mechanisms comprises a plurality of sprockets, and wherein the central transmission mechanism comprises a gear which meshes with each of the plurality of sprockets.
6. The apparatus of claim 5 , wherein the gear has a hole formed therein concentric with an axis of rotation of the gear, the hole being sized to accommodate a spindle for a rotary chuck.
7. The apparatus of claim 3 wherein each lift pin further comprises a mechanism for preventing lift pin rotation relative to the respective pin rotation mechanism.
8. The apparatus of claim 7 wherein the mechanism for preventing lift pin rotation comprises a spline and a guide through which the spline lifts and lowers.
9. The apparatus of claim 1 further comprising:
a pin lift/lower mechanism adapted to move the pins along the longitudinal axes of the pins; and
a controller operatively coupled to the pin rotation mechanism and the pin lift/lower mechanism and adapted to control the pin rotation mechanism and the pin lift/lower mechanism such that the pin rotation mechanism rotates the pins from the first position to the second position while the pin lift/lower mechanism is lowering the pins.
10. An apparatus for supporting and centering a substrate, comprising:
a substrate chuck having:
a plurality of pins, each pin having a top surface and a longitudinal axis of rotation, the top surfaces of the pins defining a plane in which the substrate is supported, each pin having a tab mounted eccentrically with respect to the pin's longitudinal axis of rotation at the top surface of the pin and extending upwardly relative to the top surface of the pin;
a pin rotation mechanism adapted to rotate each pin about a longitudinal axis of the respective pin, the pin rotation mechanism rotating the pins between a first position in which the tabs define an envelope that is larger than a circumference of the substrate and a second position in which the tabs define a centered position for the substrate;
a pin lift/lower mechanism adapted to move the pins along the longitudinal axes of the pins; and
a controller operatively coupled to the pin rotation mechanism and the pin lift/lower mechanism and adapted to control the pin rotation mechanism and the pin lift/lower mechanism such that the pin rotation mechanism rotates the pins from the first position to the second position while the pin lift/lower mechanism is lowering the pins.
11. An apparatus for supporting and centering a substrate, comprising:
a plurality of pins, each pin having a top surface and a longitudinal axis of rotation, the top surfaces of the pins defining a plane in which the substrate is supported, each pin having a tab mounted eccentrically with respect to the pin's longitudinal axis of rotation at the top surface of the pin and extending upwardly relative to the top surface of the pin; and
a pin rotation mechanism adapted to rotate each pin about a longitudinal axis of the respective pin, the pin rotation mechanism rotating the pins between a first position in which the tabs define an envelope that is larger than a circumference of the substrate and a second position in which the tabs define a centered position for the substrate.
12. The apparatus of claim 11 , further comprising:
a pin lift/lower mechanism adapted to move the pins along the longitudinal axes of the pins.
13. The apparatus of claim 12 , further comprising:
a controller operatively coupled to the pin rotation mechanism and the pin lift/lower mechanism and adapted to control the pin rotation mechanism and the pin lift/lower mechanism such that the pin rotation mechanism rotates the pins from the first position to the second position while the pin lift/lower mechanism is lowering the pins.
14. A method of centering a substrate, comprising:
supporting the substrate on a plurality of pins; and
rotating each pin about a longitudinal axis of the pin to bring a tab on each pin in contact with the substrate.
15. The method of claim 14 , wherein each pin is rotated substantially 90°.
16. The method of claim 14 , further comprising:
lowering the substrate, via the plurality of pins, onto a chuck after the rotating step.
17. The method of claim 16 , further comprising:
lowering the substrate during the rotating step.
18. The method of claim 14 , further comprising:
moving the substrate in a vertical direction during the rotating step.
19. The method of claim 18 , wherein the moving step includes lowering the substrate.
20. The method of claim 18 , wherein the moving step includes lifting the substrate.
21. A method of centering a substrate, comprising:
supporting the substrate on a plurality of pins; and
rotating each pin about a longitudinal axis of the pin to bring a tab on each pin into proximity with an edge of the substrate to thereby center the substrate.
22. The method of claim 21 , wherein each pin is rotated substantially 90°.
23. The method of claim 21 , further comprising:
lowering the substrate, via the plurality of pins, onto a vacuum chuck after the rotating step.
24. The method of claim 21 , further comprising:
moving the substrate in a vertical direction during the rotating step.
25. A method of centering a substrate, comprising:
supporting the substrate on a plurality of pins;
rotating each pin in a first direction about a longitudinal axis of the pin to bring a tab on each pin into contact with the substrate; and
rotating each pin in a second direction that is opposite to the first direction to move the tabs out of contact with the substrate, leaving the substrate in a centered position.
26. The method of claim 25 , further comprising:
lowering the substrate, via the plurality of pins, onto a chuck after the second rotating step.
27. The method of claim 26 , further comprising:
lowering the substrate during at least one of the rotating steps.
28. The method of claim 27 , wherein the substrate is lowered during both of the rotating steps.
29. The method of claim 25 , wherein each pin is rotated less than 1° during the second rotating step.
30. The method of claim 28 , further comprising:
lowering the substrate during at least one of the rotating steps.