System and method of fast ambient switching for rapid thermal processing

• US 20030038127A1
• Filed: 08/23/2001
• Published: 02/27/2003
• Est. Priority Date: 08/23/2001
• Status: Active Grant

• Current Assignee: Axcelis Technologies Incorporated
• Original Assignee: Axcelis Technologies Incorporated
• Inventors: Hebb, Jeffrey P., Liu, Yong, Drislane, William Francis
• Granted Patent: US 6,753,506 B2
• Time in Patent Office: Days
• US Class Current: 219/390
• CPC Class Codes: C23C 16/45542 Plasma being used non-continuously during the ALD reactions
• CPC Class Codes: C23C 16/45544 characterized by the apparatus
• CPC Class Codes: C23C 16/4557 Heated nozzles
• CPC Class Codes: C23C 16/45591 Fixed means, e.g. wings, baffles
• CPC Class Codes: C23C 16/46 characterised by the method used for heating the substrate C23C16/48, C23C16/50 take precedence
• CPC Class Codes: C30B 25/14 Feed and outlet means for the gases; Modifying the flow of the reactive gases
• CPC Class Codes: C30B 31/16 Feed and outlet means for the gases; Modifying the flow of the gases
• CPC Class Codes: H01L 21/67109 mainly by convection
• CPC Class Codes: H01L 21/67115 mainly by radiation
• CPC Class Codes: H01L 21/6719 characterized by the construction of the processing chambers, e.g. modular processing chambers

Abstract

A method and apparatus for thermal processing of a workpiece is provided. The time taken for a processing gas to be purged, or switched, during one or more processing steps is significantly reduced for thermal processing systems. The thermal processing system includes a heating chamber in accordance with one example embodiment of the present invention. A small-volume workpiece enclosure is disposed about the workpiece. A translation mechanism, e.g., in the form of a positioning assembly, supports the small-volume workpiece enclosure for moving the small-volume workpiece enclosure and the workpiece within the heating chamber. The small-volume workpiece enclosure enables the use of relatively smaller amounts of process (ambient) gases, and decreases the purge time of such gases. The heating chamber can have at least one of a thermal radiation intensity gradient and a temperature gradient for thermally processing the workpiece. The heating chamber can have one or more heating elements disposed about the heating chamber.

Claims

1. A thermal processing apparatus for processing a workpiece, comprising:

a heating chamber;

a small-volume workpiece enclosure disposed about said workpiece; and

a positioning assembly supporting said small-volume workpiece enclosure for moving said small-volume workpiece enclosure and said workpiece within said heating chamber.

2. The thermal processing apparatus of claim 1, wherein said heating chamber comprises at least one of a thermal radiation intensity gradient and a temperature gradient for thermally processing said workpiece.

3. The thermal processing apparatus of claim 1, further comprising heating elements disposed about said heating chamber.

4. The thermal processing apparatus of claim 1, wherein said furnace includes a bell jar forming said heating chamber.

5. The thermal processing apparatus of claim 1, further comprising a gas supply coupled to said small-volume workpiece enclosure for introducing one or more gases into said small-volume workpiece enclosure.

6. The thermal processing apparatus of claim 5, further comprising a heating mechanism for pre-heating said gas supply and said gases.

7. The thermal processing apparatus of claim 5, further comprising a gas diffuser disposed within said small-volume workpiece enclosure for regulating a flow of said gas within said small-volume workpiece enclosure.

8. The thermal processing apparatus of claim 7, wherein said gas diffuser at least partially regulates the temperature of said workpiece.

9. The thermal processing apparatus of claim 7, wherein said gas diffuser is formed of one of quartz, quartz fiber, ceramic, silicon carbide, and sapphire materials.

10. The thermal processing apparatus of claim 7, wherein said gas diffuser has a reflective surface that reflects thermal radiation unabsorbed by said workpiece to at least partially regulate the temperature of said workpiece.

11. The thermal processing apparatus of claim 10, wherein said reflective surface has a uniform reflectivity.

12. The thermal processing apparatus of claim 10, wherein said reflective surface has a non-uniform reflectivity.

13. The thermal processing apparatus of claim 7, where said gas diffuser has a surface with a reflectivity being one of uniform and varying as a function of a location on said diffuser to effect temperature uniformity of said workpiece.

14. The thermal processing apparatus of claim 13, wherein said gas diffuser is adapted to uniformly heat the workpiece.

15. The thermal processing apparatus of claim 7, wherein said gas diffuser is adapted to pre-heat a gas flowing through said small-volume workpiece enclosure.

16. The thermal processing apparatus of claim 7, further comprising a window formed within said gas diffuser.

17. The thermal processing apparatus of claim 7, further comprising:

a window within said gas diffuser;

a temperature sensor disposed relative to said workpiece; and

a mounting device for positioning said workpiece within said small-volume workpiece enclosure;

wherein said window provides an optical path for said temperature sensor to attain a temperature of said workpiece.

18. The thermal processing apparatus of claim 1, wherein said small-volume workpiece enclosure is formed of at least a first section and a second section.

19. The thermal processing apparatus of claim 18, further comprising at least one support structure coupled to said first section of said small-volume workpiece enclosure, such that when said small-volume workpiece enclosure is lowered to a base of said thermal processing apparatus, said at least one support structure supports said first section of said small-volume workpiece enclosure and said second section of said small-volume workpiece enclosure separates from said first section, allowing loading and unloading of said workpiece into and out of said small-volume workpiece enclosure.

20. The thermal processing apparatus of claim 1, further comprising a temperature sensor disposed relative to said workpiece for determining the temperature of said workpiece.

21. The thermal processing apparatus of claim 20, wherein said temperature sensor comprises a pyrometer.

22. The thermal processing apparatus of claim 20, wherein said temperature sensor comprises a thermocouple.

23. The thermal processing apparatus of claim 1, further comprising at least one aperture formed in a wall of said small-volume workpiece enclosure, such that gas supplied to said small-volume workpiece enclosure can escape through said at least one aperture.

24. The thermal processing apparatus of claim 1, further comprising means disposed within said heating chamber for exhausting gas from said heating chamber.

25. The thermal processing apparatus of claim 1, further comprising an interior wall separating said small-volume workpiece enclosure into an outer sub-compartment and an inner sub-compartment.

26. The thermal processing apparatus of claim 25, wherein said interior wall comprises at least one aperture.

27. The thermal processing apparatus of claim 25, further comprising a gas exhaust in communication with said small-volume workpiece enclosure for exhausting gas in said small-volume workpiece enclosure to a location external to said thermal processing apparatus.

28. The thermal processing apparatus of claim 25, further comprising one or more gas conduits for introducing at least one process gas into said inner sub-compartment of said small-volume workpiece enclosure.

29. The thermal processing apparatus of claim 1, wherein said small-volume workpiece enclosure is made of material at least partially transparent to thermal radiation.

30. The thermal processing apparatus of claim 1, wherein said small-volume workpiece enclosure is made of material that is one of reflective, semi-transparent, and opaque to thermal radiation.

31. The thermal processing apparatus of claim 1, wherein said small-volume workpiece enclosure contains one or more thermal radiation shields, reflectors, and optical components, disposed about said workpiece to regulate the temperature of said workpiece.

32. The thermal processing apparatus of claim 1, wherein a ratio of the volume of said heating chamber to the volume of said small-volume workpiece enclosure is greater than approximately 2.

33. The thermal processing apparatus of claim 1, wherein said positioning assembly comprises at least one of a gas input conduit for supplying gas and a gas exhaust conduit for exhausting gas.

34. The thermal processing apparatus of claim 1, wherein said positioning assembly contains at least one path between said workpiece and a temperature sensor, for radiation emitted from said workpiece and at least one thermal radiation source.

35. The thermal processing apparatus of claim 34, wherein said path for radiation can be purged with gas that does not absorb thermal radiation.

36. The thermal processing apparatus of claim 1, wherein said positioning assembly contains at least one path between said workpiece and a temperature sensor, for an electrical signal to pass.

37. The thermal processing apparatus of claim 1, wherein said small-volume workpiece enclosure utilizes said workpiece as a wall section to confine process gas inside said enclosure.

38. The thermal processing apparatus of claim 1, further comprising a gas diffuser disposed external to said small-volume workpiece enclosure for regulating the flow of gas within said small-volume workpiece enclosure to control a temperature and temperature uniformity of said workpiece.

39. The thermal processing apparatus of claim 1, further comprising an energizing device for energizing process gases prior to entering the small volume workpiece enclosure.

40. A method of thermally processing a workpiece, comprising the steps of:

providing a heating chamber for thermally processing said workpiece;

placing said workpiece into a small-volume workpiece enclosure within said heating chamber;

heating said heating chamber and said small-volume workpiece enclosure;

positioning said small-volume workpiece enclosure within said heating chamber; and

thermally processing said workpiece.

41. The method of claim 40, wherein said step of thermally processing at least partially comprises positioning said small-volume workpiece enclosure within one or more locations of the thermal processing apparatus as required to control heating levels applied to said workpiece.

42. The method of claim 40, wherein said step of thermally processing at least partially comprises supplying said small-volume workpiece enclosure with a gas to at least partially regulate heating of said workpiece.

43. The method of claim 42, further comprising pre-heating said gas prior to supplying said gas to said workpiece.

44. The method of claim 42, wherein the step of supplying said small-volume workpiece enclosure with a gas comprises regulating a flow of said gas through a diffuser.

45. The method of claim 42, wherein said step of heating said heating chamber comprises the step of activating at least one heating element.

46. The method of claim 45, wherein the step of activating at least one heating element produces thermal radiation and generates at least one of a thermal radiation gradient and a temperature gradient.

47. The method of claim 45, wherein the step of activating at least one heating element comprises activating a plurality of heating elements disposed relative to said heating chamber.

48. The method of claim 45, wherein the step of activating at least one heating element comprises activating a plurality of heating elements disposed within a bell jar.

49. The method of claim 40, further comprising the step of removing said workpiece from said heating chamber of said small-volume workpiece enclosure within said thermal processing apparatus.

50. The method of claim 40, further comprising the step of exhausting said gas from said small-volume workpiece enclosure into said thermal processing apparatus.

51. The method of claim 40, further comprising the step of venting said thermal processing apparatus to exhaust gases released from said small-volume workpiece enclosure.

52. The method of claim 40, further comprising the step of maintaining desired ambient pressures within said small-volume workpiece enclosure and said rapid thermal processing apparatus.

53. The method of claim 42, wherein the step of supplying said small-volume workpiece enclosure with a gas comprises energizing a flow of said gas to yield at least one of a plasma and a gas containing electrons, ions, radicals and energetically excited species.

54. The method of claim 42, further comprising the step of exhausting said gas through an exhaust line from said small-volume workpiece enclosure.

55. The method of claim 42, further comprising the step of exhausting said gas to said heating chamber from said small-volume workpiece enclosure to purge said gas from said small-volume workpiece enclosure.

56. A thermal processing apparatus for processing a workpiece, said thermal processing apparatus comprising a heating chamber having at least one of a thermal radiation intensity gradient and a temperature gradient, a small-volume workpiece enclosure disposed about said workpiece, and a positioning assembly supporting said small-volume workpiece enclosure for moving said small-volume workpiece enclosure and said workpiece to desired locations within said heating chamber to effect different heating levels on said workpiece, said thermal processing apparatus capable of performing one or more of:

dry and wet rapid thermal oxidation;

rapid thermal nitridation;

rapid thermal anneal for implant diffusion and metal silicides formulation;

rapid thermal BPSG reflow;

selective oxidation of Si in the presence of metal;

rapid thermal chemical vapor deposition;

low pressure chemical vapor deposition;

metal-organic chemical vapor deposition;

remote-plasma chemical vapor deposition; and

multi-layer dielectric gate stack formation.