Apparatus for aligning substrate to chuck in processing chamber

• US 6,126,382 A
• Filed: 11/26/1997
• Issued: 10/03/2000
• Est. Priority Date: 11/26/1997
• Status: Expired due to Term

• Current Assignee: Novellus Systems Incorporated (LAM Research Corporation)
• Original Assignee: Novellus Systems Incorporated (LAM Research Corporation)
• Inventors: Stowell, R. Marshall, Pechin, David A., Scales, Martin N., Benzing, Jeffrey C.
• Primary Examiner(s): MORSE, GREGORY ALLAN
• Application Number:
  US08/980,125
• Time in Patent Office: 1,042 Days
• Field of Search: 414/754, 414/757, 414/774, 414/936, 198/379, 198/394, 118/728, 118/729, 118/730
• US Class Current: 414/754
• CPC Class Codes: H01L 21/68 for positioning, orientation or alignment
• CPC Class Codes: Y10S 414/136 including wafer orienting means

Abstract

A passive mechanism for centering a wafer on a chuck and with respect to a backside exclusion gas ring includes a plurality of wheels that are rotatably mounted in a circular pattern at the top surface of a chuck. The axis of rotation of each wheel is parallel to the top surface of the chuck and perpendicular to a radius extending outward from the centerpoint of the chuck surface. When a wafer is placed on the chuck, its edge contacts the wheels and, by its own weight, the wafer moves toward the center of the chuck, thereby centering itself. The wafer either slides on the wheels or, if the frictional force between the wafer and one or more of the wheels is great enough, the wafer causes the wheel to turn. The wheels may be mounted on the chuck, a carrier ring or a wafer transfer arm for moving wafers between processing stations. In one embodiment the alignment wheels are mounted on a carrier ring, and a second alignment mechanism aligns the carrier ring to the chuck.

Claims

1. Apparatus for aligning a flat substrate with respect to another body, said apparatus comprising:

at least three rotatable wheels mounted on horizontal axles, each of the wheels being rotatable independently of the other wheels, respective edges of said wheels defining a shape substantially congruent with the shape of said flat substrate, said axles being positioned substantially in the same plane and each of the axles being aligned substantially parallel to an edge of said substrate to be contacted by the wheel mounted on said axle;

a body to which said flat substrate is to be aligned, said body having a supporting surface for supporting said flat substrate, said supporting surface being positioned generally in an area between said wheels; and

a mechanism for lowering said flat substrate from a position above said wheels to a position wherein a peripheral region of said flat substrate makes contact with at least two of said wheels.

2. The apparatus of claim 1, wherein said wheels are generally cylindrical.

3. A processing chamber for performing a process on a flat circular substrate and containing a chuck for supporting said flat circular substrate during said processing, said chamber further comprising an arrangement for aligning said flat circular substrate on said chuck, said arrangement comprising:

at least three rotatable wheels mounted on horizontal axles on said chuck, each of the wheels being rotatable independently of the other wheels, respective edges of said wheels defining a shape substantially congruent with the shape of said flat circular substrate, said axles being positioned substantially in the same plane and each of the axles being aligned substantially parallel to an edge of said flat circular substrate to be contacted by the wheel mounted on said axle; and

a mechanism for lowering said substrate from a position above said wheels to a position wherein a peripheral region of said flat circular substrate makes contact with at least two of said wheels.

4. The processing chamber of claim 3 wherein said wheels are mounted to said chuck.

5. The processing chamber of claim 4 wherein said wheels are mounted to said chuck by means of wheel holders.

6. The processing chamber of claim 4 wherein one end of each of said axles is mounted to said chuck, the other end of each of said axles remaining free.

7. The processing chamber of claim 6 wherein each of said axles is flexible.

8. The processing chamber of claim 4 wherein both ends of each of said axles is mounted to said chuck.

9. The processing chamber of claim 8 wherein each of said axles is flexible.

10. The processing chamber of claim 4 further comprising an exclusion gas ring, said exclusion gas ring being positioned such that said exclusion gas ring is centered above said flat circular substrate when said substrate is supported on said chuck.

11. The processing chamber of claim 4 comprising four of said wheels.

12. The processing chamber of claim 3 wherein said wheels are mounted to a substrate transfer arm.

13. The processing chamber of claim 12 further comprising an exclusion gas ring, said substrate transfer arm containing a first set of features, said exclusion gas ring containing a second set of features, said first and second sets of features being shaped and sized so as to correctly align said exclusion gas ring and said substrate transfer arm when said first and second sets of features are mated together.

14. The processing chamber of claim 13 wherein said first set of features comprises a plurality of pins and said second set of features comprises a plurality of slots, said slots being oriented radially with respect to a center of said exclusion gas ring when said pins and slots are mated together.

15. The processing chamber of claim 12 comprising a plurality of lips for supporting said substrate, each of said lips being located adjacent at least one of said wheels.

16. The processing chamber of claim 12 wherein a pair of wheels is located adjacent each of said lips.

17. The processing chamber of claim 12 comprising a mechanism for lowering said substrate transfer arm such that a substrate comes to rest on a supporting surface of said chuck.

18. The processing chamber of claim 12 comprising a plurality of processing stations, said substrate transfer arm being configured so as to transfer a substrate from a first processing station to a second processing station.

19. The processing chamber of claim 18 wherein said processing chamber comprises a chemical vapor deposition chamber.

20. The processing chamber of claim 18 wherein said processing chamber comprises a plasma-enhanced chemical vapor deposition chamber.

21. A processing chamber for performing a process on a substrate while said substrate is supported on a chuck, said chamber comprising:

said chuck, said chuck having a supporting surface for supporting a central region of said substrate;

a carrier ring comprising;

a first plurality of wheels rotatable about respective horizontal axes, said first plurality of wheels having edges which define a shape congruent with a shape of said substrate; and

a plurality of shelf portions for supporting a peripheral region of said substrate; and

an alignment mechanism for aligning said carrier ring to said chuck, said alignment mechanism comprising a second plurality of wheels and a plurality of alignment faces, respective ones of said alignment faces contacting one of said second plurality of wheels when said carrier ring is aligned to said chuck.

22. The processing chamber of claim 21 comprising a rotatable ball mounted in each of said shelf portions.

23. The processing chamber of claim 21 wherein said alignment faces are formed in said carrier ring and said second plurality of wheels are mounted in said chuck.

24. The processing chamber of claim 23 wherein said second plurality of wheels are mounted in pairs on opposite sides of channels, said channels being oriented radially in said chuck.

25. The processing chamber of claim 21 comprising a plurality of processing stations, said carrier ring being supported on a lift plate, said lift plate being for transporting said ring carrier from a first processing station to a second processing station.

26. The processing chamber of claim 21 wherein said chuck comprises a groove for introducing an exclusion gas.

27. The processing chamber of claim 26 wherein said carrier ring comprises an exclusion gas ring.