Method of cooling wafers

• US 6,108,937 A
• Filed: 09/10/1998
• Issued: 08/29/2000
• Est. Priority Date: 09/10/1998
• Status: Expired due to Term

• Current Assignee: ASM America Incorporated (ASM International NV)
• Original Assignee: ASM America Incorporated (ASM International NV)
• Inventors: Raaijmakers, Ivo
• Primary Examiner(s): Ferensic, Denise L.
• Assistant Examiner(s): RAGONESE, ANDREA M
• Application Number:
  US09/150,986
• Time in Patent Office: 719 Days
• Field of Search: 34/428, 34/433, 34/62, 34/391, 34/393, 34/380, 34/508, 34/448
• US Class Current: 34/433
• CPC Class Codes: C23C 16/54 Apparatus specially adapted for continuous coating
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: C30B 25/10 Heating of the reaction chamber or the substrate
• CPC Class Codes: H01L 21/67109 mainly by convection

Abstract

Methods and apparatuses are provided for cooling semiconductor substrates prior to handling. In one embodiment, a substrate and support structure combination is lifted after high temperature processing to a cold wall of a thermal processing chamber, which acts as a heat sink. Conductive heat transfer across a small gap from the substrate to the heat sink speeds wafer cooling prior to handling the wafer (e.g., with a robot). In another embodiment, a separate plate is kept cool within a pocket during processing, and is moved close to the substrate and support after processing. In yet another embodiment, a cooling station between a processing chamber and a storage cassette includes two movable cold plates, which are movable to positions closely spaced on either side of the wafer.

Claims

1. A method of treating substrates in a processing chamber, comprising:

loading a substrate onto a support structure within the processing chamber;

heating the substrate to at least one treatment temperature;

treating the substrate at the treatment temperature in a treatment position within the processing chamber;

after treating the substrate, moving an element to bring the substrate and a cooling surface of a heat sink into a cooling position within the processing chamber wherein the substrate loses heat to the cooling surface; and

maintaining the substrate and the cooling surface in the cooling position.

2. The method of claim 1, wherein the substrate and the cooling surface are spaced by between about 0.2 mm and 3.0 mm in the cooling position.

3. The method of claim 1, wherein the substrate and the cooling surface are spaced by between about 0.5 and 1.5 mm in the cooling position.

4. The method of claim 1, further comprising removing the substrate from the support structure after maintaining the substrate and the cooling surface in the cooling position, removing the substrate from the chamber, and loading a second substrate onto the support structure.

5. The method of claim 1, wherein moving the element comprises moving the heat sink.

6. The method of claim 1, wherein the heat sink is actively cooled.

7. The method of claim 6, further comprising withdrawing the heat sink from the cooling position to an actively cooled location after maintaining the substrate and the cooling surface in the cooling position.

8. The method of claim 6, wherein the element comprises the support structure, and further comprising withdrawing the element from the cooling position prior to removing the substrate from the support structure.

9. The method of claim 1, wherein the heat sink comprises at least a portion of a wall of the processing chamber, and moving the element comprises moving the support structure.

10. The method of claim 1, wherein the heat sink comprises a cooling plate, and moving the element comprises moving the plate.

11. The method of claim 1, wherein the cooling surface is substantially parallel to a surface of the substrate in the cooling position.

12. The method of claim 1, further comprising providing a purge gas to the chamber while cooling the substrate.

13. The method of claim 1, wherein a chamber pressure is maintained at a level resulting in viscous flow between the substrate and the cooling surface in the cooling position.

14. The method of claim 1, wherein the substrate remains supported upon the substrate support structure in each of the treatment and cooling positions.

15. The method of claim 1, further comprising rotating the substrate in the cooling position.

16. The method of claim 1, wherein the support structure comprises a susceptor.

17. A method for cooling a substrate after treating the substrate at at least one processing temperature while supported at a first position in a processing chamber, the method comprising moving the substrate from the first position to a second position within the processing chamber proximate a cold element, maintaining the substrate at the second position, and transferring heat from the substrate to the cold element until the substrate reaches a handling temperature lower than the processing temperature.

18. The method of claim 17, wherein the cold element comprises a cold wall of the processing chamber, the wall comprising a material substantially transparent to radiant heat.

19. The method of claim 18, wherein the wall is actively cooled by forced convection.

20. The method of claim 18, wherein the substrate has a surface, the cold wall has a flat inner surface, and the surfaces are positioned facing and substantially parallel to each other in the second position.

21. The method of claim 20, wherein the upper surface of the substrate and the inner surface of the cold wall are substantially horizontal in each of the first and second positions.

22. The method of claim 17, wherein adjacent surfaces of the substrate and the cold element are spaced apart by between about 0.2 mm and 3 mm in the second position.

23. The method of claim 17, wherein adjacent surfaces of the substrate and the cold element are spaced apart by between about 0.5 mm and 1.5 mm in the second position.

24. The method of claim 17, wherein the processing temperature is between about 1,000°

C. and 1,200°

C., the handling temperature is less than about 900°

C., and the substrate is maintained at the second position for less than about 60 seconds.

25. The method of claim 24, wherein the substrate is maintained at the second position for less than about 10 seconds.

26. The method of claim 17, wherein the processing temperature is between about 600°

C. and 1,200°

C., the handling temperature is less than about 600°

C., and the substrated is maintained at the second position for less than about 60 seconds.

27. The method of claim 26, wherein the substrate is maintained at the second position for less than about 10 seconds.

28. The method of claim 17, wherein the substrate is supported by a substrate support structure in each of the first and second positions, and moving the substrate comprises moving the substrate support structure.

29. The method of claim 17, wherein the substrate support structure comprises a susceptor supported by a shaft, and moving the substrate support structure comprises vertically extending the shaft upward toward the cold element.

30. A method of cooling a semiconductor substrate from a first temperature to a second temperature within a processing chamber, the method comprising:

moving a cooling member from a retracted position to a location adjacent and spaced from the substrate, the cooling member having a third temperature in the retracted position, the third temperature lower than the second temperature; and

maintaining the cooling member adjacent and spaced from the substrate until the substrate cools to the second temperature; and

lifting the substrate with a substrate handling device after the substrate cools to the second temperature.

31. The method of claim 30, wherein the cooling member is within an actively cooled structure at the retracted position.

32. The method of claim 30, further comprising withdrawing the cooling member from the location adjacent the substrate to the retracted position after the substrate cools to the second temperature.

33. The method of claim 30, wherein moving the cooling member comprises horizontally translating the cooling member to the location adjacent the substrate, the cooling member having a cooling surface substantially parallel and vertically spaced from an upper surface of the substrate.

34. The method of claim 33, wherein the upper surface of the substrate is spaced by between about 0.5 mm and 1.5 mm from the cooling surface of the cooling member.

35. The method of claim 33, wherein the cooling member is sheltered within the processing chamber from a heat source at the retracted position.

36. A method of cooling a semiconductor substrate from a first temperature to a second temperature within a chamber, the method comprising:

moving a cooling member from a retracted position to a location adjacent and spaced from the substrate, the cooling member having a third temperature in the retracted position, the third temperature lower than the second temperature; and

maintaining the cooling member adjacent and spaced from the substrate until the substrate cools to the second temperature;

lifting the substrate with a substrate handling device after the substrate cools to the second temperature; and

moving a second cooling member to a position adjacent and spaced from the substrate on an opposite side of the substrate from the cooling member, and simultaneously transferring heat from the substrate to each of the cooling member and the second cooling member.

37. The method of claim 36, wherein the second cooling member comprises a movable platform beneath a wafer supported on pins.

38. The method of claim 36, wherein the chamber comprises a cooling chamber adjacent a substrate processing chamber.