High density plasma source for semiconductor processing

• US 6,028,285 A
• Filed: 11/19/1997
• Issued: 02/22/2000
• Est. Priority Date: 11/19/1997
• Status: Expired due to Fees

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Cherrington, Blake E., Khater, Marwan H., Overzet, Lawrence J.
• Primary Examiner(s): PASCHALL, MARK H
• Application Number:
  US08/974,111
• Time in Patent Office: 825 Days
• Field of Search: 219/121.4, 219/121.43, 219/121.52, 118/723 I, 156/345, 156/646.1, 315/111.31, 315/111.51, 315/111.21
• US Class Current: 219/121.43
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma

Abstract

An apparatus for producing a plasma (70) within a vacuum chamber (50) comprising a high density plasma source (10) is disclosed wherein the source (10) comprises a top layer (13) and a bottom layer (11) electrically connected to and spaced apart from each other, in a manner to adjust the fields generated by the source (10), hence the uniformity of the plasma (70), wherein the top and bottom layers (13, 11) are formed by a plurality of conductive loops.

Claims

1. A plasma source comprising:

a first loop forming a first layer; and

a second loop forming a second layer electrically connected to and spaced apart from said first loop, wherein subsequent conducting loops are electrically connected to loops in layers other than their own.

2. The source as recited in claim 1 wherein said first and second layers further comprise a plurality of loops.

3. The source as recited in claim 2 wherein said plurality of loops of said first layer and said second layer are generally concentric.

4. The source as recited in claim 2 wherein said plurality of loops of said first layer have a plurality of centers of rotation.

5. The source as recited in claim 2 wherein said loops of said first layer further comprise circumferential arcs between about 20 degrees and 360 degrees.

6. The source as recited in claim 5 wherein said loops of said first layer further comprise circumferential arcs between about 90 degrees and 270 degrees.

7. The source as recited in claim 2 wherein the ends of each of said loops of said first layer define a circumferential gap therebetween.

8. The source as recited in claim 7 wherein each of said circumferential gap has the same length.

9. The source as recited in claim 7 wherein each of said circumferential gap has the same arc length.

10. The source as recited in claim 2 wherein said loops of said first layer further comprise circumferential arcs between about 20 degrees and 360 degrees and said loops of said second layer further comprise circumferential arcs between about 20 degrees and 360 degrees.

11. The source as recited in claim 10 wherein said loops of said first layer further comprise circumferential arcs between about 90 degrees and 270 degrees.

12. The source as recited in claim 2 wherein adjacent loops of said second layer define radial gaps therebetween and wherein at least one of said loops of said first layer is disposed radially between at least one of said radial gaps.

13. The source as recited in claim 2 wherein at least one of said loops of said second layer has the same radius as at least one of said loops of said first layer.

14. The source as recited in claim 2 wherein the cross-sectional area of at least one of said loops of said first layer is greater than the cross-sectional area of at least one of the other of said loops of said first layer.

15. The source as recited in claim 2 wherein the cross-sectional area of at least one of said loops of said first layer varies along the length of said at least one of loops of said first layer.

16. The source as recited in claim 2 wherein a current flows in a first direction in at least one of said loops of said first layer and in a second direction in at least one of said loops of said second layer.

17. The source as recited in claim 2 wherein said loops of said first layer each have the same radius such that said loops of said first layer substantially form a circle.

18. The source as recited in claim 2 wherein half of said loops of said first layer have a first radius and the other half of said loops of said first layer have a second radius such that said loops of said first layer substantially form first and second circles.

19. The source as recited in claim 1 wherein said first layer has a substantially planar profile.

20. The source as recited in claim 1 wherein said first layer has a non-planar profile.

21. The source as recited in claim 1 further comprising a support structure disposed generally between said first and second layers.

22. The source as recited in claim 1 further comprising at least one spacer member disposed generally between said first and second layers.

23. An apparatus for generating a uniform plasma in a chamber by producing magnetic fields of high symmetry comprising:

a first layer of loops; and

a second layer of loops electrically connected to and spaced apart from said first layer of loops, wherein alternating loops are electrically connected to loops in layers other than their own.

24. The source as recited in claim 23 wherein said loops of said first layer further comprise circumferential arcs between about 20 degrees and 360 degrees.

25. The source as recited in claim 23 wherein the ends of each of said loops of said first layer define a circumferential gap therebetween.

26. The source as recited in claim 25 wherein each of said circumferential gap has the same length.

27. The source as recited in claim 25 wherein each of said circumferential gap has the same arc length.

28. The source as recited in claim 23 wherein said loops of said first layer further comprise circumferential arcs between about 20 degrees and 360 degrees and said loops of said second layer further comprise circumferential arcs between about 20 degrees and 360 degrees.

29. The source as recited in claim 23 wherein adjacent loops of said second layer define radial gaps therebetween and wherein at least one of said loops of said first layer is disposed radially between at least one of said radial gaps.

30. The source as recited in claim 23 wherein at least one of said loops of said second layer has the same radius as at least one of said loops of said first layer.

31. The source as recited in claim 23 wherein the cross-sectional area of at least one of said loops of said first layer near the perimeter of said source is greater than the cross-sectional area of at least one of said loops of said first layer near the center of said source.

32. The source as recited in claim 23 wherein the cross-sectional area of at least one of said loops of said first layer near the center of the source is greater than the cross-sectional area of at least one of said loops of said first layer near the perimeter of said source.

33. The source as recited in claim 23 wherein a current flows in a first direction in at least one of said loops of said first layer and in a second direction in at least one of said loops of said second layer.

34. The source as recited in claim 23 wherein said loops of said first layer each have the same radius such that said loops of said first layer substantially form a circle.

35. The source as recited in claim 23 wherein half of said loops of said first layer have a first radius and the other half of said loops of said first layer have a second radius such that said loops of said first layer substantially form first and second circles.

36. The source as recited in claim 23 wherein said first layer has a substantially planar profile.

37. The source as recited in claim 23 wherein said first layer has a non-planar profile.

38. The source as recited in claim 23 further comprising a support structure disposed generally between said first and second layers.

39. The source as recited in claim 23 further comprising at least one spacer member disposed generally between said first and second layers.