Reactor filament assembly with enhanced misalignment tolerance

• US 10,450,649 B2
• Filed: 01/29/2014
• Issued: 10/22/2019
• Est. Priority Date: 01/29/2014
• Status: Active Grant

• Current Assignee: Advanced Material Solutions, LLC
• Original Assignee: GTAT Corporation (ON Semiconductor Corporation)
• Inventors: Rhodes, Aaron D, Ballenger, Keith H
• Primary Examiner(s): Bennett, Charlee J C
• Application Number:
  US14/166,879
• Publication Number:
  US 20150211111A1
• Time in Patent Office: 2,092 Days
• Field of Search: 427248
• CPC Class Codes: C01B 33/035 by decomposition or reduction of gaseous or vaporised silicon compounds in the presence of heated filaments of silicon, carbon or a refractory metal, e.g. tantalum or tungsten, or in the presence of heated silicon rods on which the formed silicon is deposited, a silicon rod being obtained, e.g. Siemens process
• CPC Class Codes: C23C 16/24 Deposition of silicon only
• CPC Class Codes: C23C 16/4418 Methods for making free-standing articles C23C16/01 takes precedence

Abstract

A tubular filament assembly for a CVD silicon deposition reactor is disclosed that provides consistent, low resistance connections to vertical tubular filaments by forming slidable connections between upper and/or lower ends of the tubular filaments and shaped elements cooperative with the bridge and/or the support chucks, so that the connections are insensitive at least to small variations in tilt angle of the vertical filaments and/or the horizontal bridge. The shaped elements can be incorporated into or separate and cooperative with the bridge and/or the chucks. Various embodiments are described.

Claims

1. A CVD reactor for bulk production of polysilicon, comprising:

a base plate configured with a first filament support chuck and a second filament support chuck;

an enclosure attachable to said base plate so as to form a deposition chamber; and

a filament assembly comprising;

a first tubular silicon filament, said first tubular silicon filament being vertically oriented and having a bottom end making an electrical connection with said first filament support chuck;

a second tubular silicon filament, said second tubular silicon filament being vertically oriented and having a bottom end making an electrical connection with said second filament support chuck, said first and second tubular silicon filaments being non-concentric;

a horizontal bridge configured for electrically connecting top ends of said first and second tubular silicon filaments, such that current flowing between the first and second tubular filaments is required to flow through the bridge;

a first shaped element forming an electrical connection between the horizontal bridge and the top of the first tubular filament, said first shaped element having a first peripheral surface surrounding a substantially vertical central axis of the first shaped element, said first peripheral surface being slanted or curved so as to form a first region of contact that is slidable against a perimeter of said top end of said first tubular silicon filament when said first peripheral surface is placed adjacent to said top end of the first tubular silicon filament and an angle between the vertical central axis of the first shaped element and a vertical central axis of the first tubular silicon filament is varied;

said first peripheral surface being configured to maintain at least 50% of said first region of contact when the angle between the central axis of the first shaped element and the central axis of the first tubular silicon filament is varied up to a maximum tilt angle; and

a second shaped element forming an electrical connection between the horizontal bridge and the top of the second tubular filament, said second shaped element having a second peripheral surface surrounding a substantially vertical central axis of the second shaped element, said second peripheral surface being slanted or curved so as to form a second region of contact that is slidable against a perimeter of said top end of said second tubular silicon filament when said second peripheral surface is placed adjacent to said top end of the second tubular silicon filament and an angle between the vertical central axis of the second shaped element and a vertical central axis of the second tubular silicon filament is varied;

said second peripheral surface being configured to maintain at least 50% of said second region of contact when the angle between the central axis of the second shaped element and the central axis of the second tubular silicon filament is varied up to a maximum tilt angle.

2. The CVD reactor of claim 1, wherein the first tubular silicon filament has a cross section shaped as a circular annulus.

3. The filament assembly of claim 1, wherein said first and second shaped elements are male elements in electrical communication with first and second ends, respectively, of said horizontal bridge, said first and second peripheral surfaces being slanted or curved outward to rest on inner perimeters of the tops of the first and second tubular silicon filaments.

4. The filament assembly of claim 1, wherein said first shaped element is a female element in electrical communication with a first end of said horizontal bridge, said first peripheral surface being slanted or curved inward to rest on an outer perimeter of the top of the first tubular silicon filament.

5. The filament assembly of claim 1, wherein the top end of the first tubular silicon filament includes a chamfer that is slanted or curved so as to be compatible with the first peripheral surface of the first shaped element for said first slidable region of contact.

6. The CVD reactor of claim 1, wherein the first shaped element is incorporated into the horizontal bridge.

7. The CVD reactor of claim 1 wherein the first shaped element is recessed into a lower surface of a first end of the horizontal bridge.

8. The CVD reactor of claim 1, wherein the first peripheral surface of the first shaped element is a wall of a groove formed in a lower surface of a first end of the horizontal bridge.

9. The CVD reactor of claim 1, wherein the first shaped element extends below a lower surface of the horizontal bridge.

10. The CVD reactor of claim 1, wherein the first peripheral surface is a sloped, substantially flat surface.

11. The CVD reactor of claim 1, wherein the first peripheral surface is shaped as a section of a sphere taken perpendicular to a diameter of the sphere.

12. The CVD reactor of claim 1, wherein an angle between the first peripheral surface and the central axis of the first shaped element is approximately 45 degrees.

13. The CVD reactor of claim 1, wherein the first tubular silicon filament has a cross section shaped as a hollow rectangle.

14. The CVD reactor of claim 1, wherein the first shaped element includes a separate component, distinct from the bridge and the tubular silicon filaments.

15. The CVD reactor of claim 14, wherein the separate component is in direct physical contact with the horizontal bridge or the first tubular silicon filament.

16. The CVD reactor of claim 1, wherein said first peripheral surface is configured to maintain at least 75% of said first region of contact when the angle between the central axis of the first shaped element and the central axis of the first tubular silicon filament is varied up to the maximum tilt angle.

17. The CVD reactor of claim 1, wherein said first peripheral surface is configured to maintain at least 90% of said region of contact when the angle between the central axis of the first shaped element and the central axis of the first tubular silicon filament is varied up to a maximum tilt angle.

18. A filament assembly configured for bulk production of polysilicon in a CVD reactor, said CVD reactor including a base plate configured with a first filament support chuck and a second filament support chuck, said filament assembly comprising:

a first tubular silicon filament, said first tubular silicon filament being vertically oriented and having a bottom end configured to make an electrical connection with said first filament support chuck;

a second tubular silicon filament, said second tubular silicon filament being vertically oriented and having a bottom end configured to make an electrical connection with said second filament support chuck, said first and second tubular silicon filaments being non-concentric;

a horizontal bridge configured for electrically connecting top ends of said first and second tubular silicon filaments, such that current flowing between the first and second tubular filaments is required to flow through the bridge;

a first shaped element proximal to a first end of said horizontal bridge and forming an electrical connection between the horizontal bridge and the top of the first tubular filament, the first shaped element having a first peripheral surface surrounding a substantially vertical central axis of the first shaped element, said first peripheral surface being slanted or curved so as to form a first region of contact that is slidable against a perimeter of said top end of said first tubular silicon filament when said first peripheral surface is placed on top of said first tubular silicon filament and an angle between the vertical central axis of the first shaped element and a vertical central axis of the first tubular silicon filament is varied;

said first peripheral surface being configured to maintain at least 50% of said first region of contact when an angle between the vertical central axis of the first shaped element and a vertical central axis of the first tubular silicon filament is varied up to a maximum tilt angle; and

a second shaped element proximal to a second end of said horizontal bridge and forming an electrical connection between the horizontal bridge and the top of the second tubular filament, the second shaped element having a second peripheral surface surrounding a substantially vertical central axis of the second shaped element, said second peripheral surface being slanted or curved so as to form a second region of contact that is slidable against a perimeter of said top end of said second tubular silicon filament when said second peripheral surface is placed on top of said second tubular silicon filament and an angle between the vertical central axis of the second shaped element and a vertical central axis of the second tubular silicon filament is varied;

said second peripheral surface being configured to maintain at least 50% of said second region of contact when an angle between the vertical central axis of the second shaped element and a vertical central axis of the second tubular silicon filament is varied up to a maximum tilt angle.

19. The filament assembly of claim 18, wherein the first tubular silicon filament has a cross section shaped as a circular annulus.

20. The filament assembly of claim 18, wherein said first shaped element is a male element, said first peripheral surface being slanted or curved outward to rest on an inner perimeter of the top of the first tubular silicon filament.

21. The filament assembly of claim 18, wherein said first shaped element is a female element, said first peripheral surface being slanted or curved inward to rest on an outer perimeter of the top of the first tubular silicon filament.

22. The filament assembly of claim 18, wherein the top end of the first tubular silicon filament includes a perimeter that is slanted or curved so as to be compatible with the first peripheral surface of the first shaped element for said first slidable region of contact.

23. The filament assembly of claim 18, wherein the first tubular silicon filament has a cross section shaped as a hollow rectangle.

24. The filament assembly of claim 18, wherein the top end of the first tubular silicon filament is shaped as a horizontal, flat annulus.

25. The filament assembly of claim 18, wherein the first shaped element is a separate component, distinct from the tubular silicon filaments and the horizontal bridge.

26. The filament assembly of claim 18, wherein said first peripheral surface is configured to maintain at least 75% of said first region of contact when the angle between the central axis of the first shaped element and the central axis of the first tubular silicon filament is varied up to a maximum tilt angle.

27. The filament assembly of claim 18, wherein said first peripheral surface is configured to maintain at least 90% of said first region of contact when the angle between the central axis of the first shaped element and the central axis of the first tubular silicon filament is varied up to a maximum tilt angle.

28. A horizontal filament bridge configured for electrically connecting top ends of a first vertical tubular silicon filament and a second vertical tubular silicon filament in a CVD reactor, such that current flowing between the first and second tubular filaments is required to flow through the bridge, said first and second tubular silicon filaments being non-concentric, said horizontal filament bridge comprising:

a horizontal bridge;

a first shaped element proximal to a first end of the horizontal bridge and forming an electrical connection between the horizontal bridge and the top of the first tubular filament, the first shaped element having a first peripheral surface surrounding a substantially vertical central axis of the first shaped element, said first peripheral surface being slanted or curved so as to form a first region of contact that is slidable against a perimeter of said top of the first tubular silicon filament when said first peripheral surface is placed on top of said first tubular silicon filament and an angle between the vertical central axis of the first shaped element and a vertical central axis of the first tubular silicon filament is varied;

said first peripheral surface being configured to maintain at least 50% of said first region of contact when an angle between the vertical central axis of the first shaped element and a vertical central axis of the first tubular silicon filament is varied up to a maximum tilt angle; and

a second shaped element proximal to a second end of the horizontal bridge and forming an electrical connection between the horizontal bridge and the top of the second tubular filament, the second shaped element having a second peripheral surface surrounding a substantially vertical central axis of the second shaped element, said second peripheral surface being slanted or curved so as to form a second region of contact that is slidable against a perimeter of said top of the second tubular silicon filament when said second peripheral surface is placed on top of said second tubular silicon filament and an angle between the vertical central axis of the second shaped element and a vertical central axis of the second tubular silicon filament is varied;

said second peripheral surface being configured to maintain at least 50% of said second region of contact when an angle between the vertical central axis of the second shaped element and a vertical central axis of the second tubular silicon filament is varied up to a maximum tilt angle.

29. The horizontal filament bridge of claim 28, wherein said first shaped element is a male element, said first peripheral surface being slanted or curved inward to rest on an inner perimeter of the top of the first tubular silicon filament.

30. The horizontal filament bridge of claim 28, wherein said first shaped element is a female element, said first peripheral surface being slanted or curved inward to rest on an outer perimeter of the top of the first tubular silicon filament.

31. The horizontal filament bridge of claim 28, wherein the first shaped element is incorporated into the horizontal bridge.

32. The horizontal filament bridge of claim 28, wherein the first shaped element includes a separate component, distinct from the horizontal bridge.

33. The horizontal filament bridge of claim 28, wherein the first tubular silicon filament has a cross section shaped as a circular annulus.

34. The horizontal filament bridge of claim 28, wherein said first peripheral surface is configured to maintain at least 75% of said first region of contact when the angle between the central axis of the first shaped element and the central axis of the first tubular silicon filament is varied up to a maximum tilt angle.

35. The horizontal filament bride of claim 28, wherein said first peripheral surface is configured to maintain at least 90% of said region of contact when the angle between the central axis of the first shaped element and the central axis of the first tubular silicon filament is varied up to a maximum tilt angle.