Method and apparatus for shaping a magnetic field in a magnetic field-enhanced plasma reactor

• US 20040182516A1
• Filed: 02/13/2004
• Published: 09/23/2004
• Est. Priority Date: 02/14/2003
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Horioka, Keiji, Pu, Bryan Y., Liu, Jingbao, Lindley, Roger Alan
• Granted Patent: US 7,422,654 B2
• Time in Patent Office: Days
• US Class Current: 156/345.46
• CPC Class Codes: H01J 37/32623 Mechanical discharge control means
• CPC Class Codes: H01J 37/3266 Magnetic control means
• CPC Class Codes: H01J 37/32688 Multi-cusp fields

Abstract

A magnetic field generator which provides greater control over the magnetic field is provided. The magnetic field generator has a plurality of overlapping main magnetic coil sections for forming a magnetic field generally parallel to the top surface of the supporting member. In other embodiments, sub-magnetic coil sections are placed symmetrically around the main magnetic coil sections.

Claims

1. A magnetic field generator in a semiconductor substrate processing system comprising:

a plurality of overlapping main magnetic coils for forming a magnetic field generally parallel to a top surface of a substrate support.

2. The magnetic field generator of claim 1, wherein each main magnetic coil has two ends and each end of each main magnetic coil overlaps an end of an adjacent main magnetic coil.

3. The magnetic field generator of claim 2, wherein sub-magnetic coils are proximate to the overlapping ends of the main magnetic coils.

4. The magnetic field generator of claim 1, wherein at least one main magnetic coil is overlapped by two adjacent main magnetic coils.

5. The magnetic field generator of claim 1, wherein each main magnetic coil has two ends and two of said main magnetic coils are oppositely positioned to each other and said two have adjacent ends overlapped by a same main magnetic coil.

6. The magnetic field generator of claim 5, wherein each end is curved.

7. The magnetic field generator of claim 6, further comprising sub-magnetic coils proximate to the overlapping ends of the main magnetic coils.

8. The magnetic field generator of claim 1, wherein said plurality comprises a first pair and a second pair of main magnetic coils, each main magnetic coil in said first pair is positioned about 180 degrees from each other and each main magnetic coil in said second pair is positioned about 180 degrees from each other, each main magnetic coil in said plurality has two ends, wherein one end of each main magnetic coil in said first pair is overlapped by a first main magnetic coil in said second pair and the other end of each main magnetic coil in said first pair is overlapped by a second main magnetic coil in said second pair.

9. The magnetic field generator of claim 8, wherein sub-magnetic coils proximate to the overlapping ends of the main magnetic coils.

10. The magnetic field generator of claim 8, wherein spaces are formed between adjacent ends of main magnetic coils in each respective pair and sub-magnetic coils are adjacent to each space.

11. The magnetic field generator of claim 1, wherein said plurality of overlapping main magnetic coils comprises a first sub-plurality of main magnetic coils and a second sub-plurality of main magnetic coils, each main magnetic coil in said plurality of overlapping main magnetic coils has two ends, wherein spaces are formed between the ends of adjacent main magnetic coils in said first sub-plurality, and spaces are formed between the ends of adjacent main magnetic coils in said second sub-plurality, said first sub-plurality is offset from said second sub-plurality by about 180 degrees.

12. The magnetic field generator of claim 11, wherein a sub-magnetic coil is proximate to each respective space.

13. The magnetic field generator of claim 1, wherein said plurality comprises a sub-plurality of main magnetic coils and a sub-plurality of sub-magnetic coils, each main magnetic coil has two ends and is adjacent to another main magnetic coil to form spaces between adjacent main magnetic coils, and each coil in said sub-plurality of sub-magnetic coils is proximate to a space.

15. The magnetic coil configuration of claim 1, wherein each coil in said plurality has two ends, said plurality comprises a first plurality of main magnetic coils and a second plurality of sub-magnetic coils, wherein both ends of each main magnetic coil is adjacent to an end of one of said sub-magnetic coils, and each respective sub-magnetic coil in a third plurality of sub-magnetic coils is proximate to one of said sub-magnetic coils in said second plurality.

16. The magnetic field generator of claim 1, wherein each main magnetic coil has two ends and one end of each main magnetic coil overlaps an end of an adjacent main magnetic coil to form overlapping and non-overlapping portions and sub-magnetic coils are positioned proximate to said non-overlapping portions.

17. The magnetic field generator of claim 1, further comprising:

a first plurality of sub-magnetic coils, where each one of the sub-magnetic coil sections is associated with adjacent main magnetic coils.

18. The magnetic field generator of claim 17, further comprising:

a second plurality of sub-magnetic coils positioned near a top portion of said main magnetic coils.

19. The magnetic field generator of claim 18, further comprising:

a third plurality of sub-magnetic coils positioned near a bottom portion of said main magnetic coils.

20. The magnetic field generator of claim 17, wherein the dimensions of said sub-magnetic coils are smaller than the dimensions of said main magnetic coils.

21. The magnetic field generator of claim 17, wherein said sub-magnetic coils are placed between said overlapping portions.

22. The magnetic field generator of claim 17, further comprising other pluralities of sub-magnetic coils positioned proximate to each said main magnetic coil.

23. The magnetic field generator of claim 17, further comprising a first current supply for supplying electric currents to said main magnetic coil sections and with a second current supply for supplying electric currents to sub-magnetic coil sections.

24. The magnetic field generator of claim 18, further comprising:

a plurality of sub-magnetic coils, wherein each main magnetic coil and each sub-magnetic coil has a separate current source.

25. The magnetic field generator of claim 1 wherein each main magnetic coil has one end that is overlapped by an adjacent main magnetic coil and another end that overlaps another adjacent main magnetic coil.

14. The magnetic field generator of claim 14, further comprising another plurality of sub-magnetic coils wherein each sub-magnetic coil in said another plurality is adjacent to a coil in said sub-plurality of sub-magnetic coils.

26. A magnetic field generator in a semiconductor substrate processing system comprising:

a plurality of first coils that form a first magnetic field having a convex shape; and

a plurality of second coils, positioned proximate to said plurality of first coils, for providing a second magnetic field having a concave shape, where a combination of said first magnetic field and said second magnetic field form a magnetic field having a desired shape.

27. The magnetic field generator of claim 26 further comprising:

a plurality of first current sources coupled to said first coils; and

a plurality of second current sources coupled to said second coils.

28. The magnetic field generator of claim 26 further comprising:

a plurality of first current sources coupled to said first and second coils.

29. A method of forming a magnetic field in a semiconductor substrate processing system comprising:

energizing a plurality of first coils to form a first magnetic field having a convex shape;

energizing a plurality of second coils to form a second magnetic field having a concave shape;

combining the first magnetic field and the second magnetic field to form a magnetic field having a desired shape.

30. The method of claim 29 further comprising:

applying a first plurality of currents to the plurality of first coils to energize the plurality of first coils; and

applying a second plurality of currents to the plurality of second coils to energize the plurality of second coils.

31. The method of claim 30 further comprising:

generating a magnetic field having a particular gradient and shape defined by a ratio of currents applied to the pluralities of first and second coils.

32. The method of claim 31 further comprising:

sequentially switching the currents applied to the pluralities of first and second coils to rotate the magnetic field.