Capacitively coupled RF-plasma reactor

• US 6,281,469 B1
• Filed: 07/23/1999
• Issued: 08/28/2001
• Est. Priority Date: 01/17/1997
• Status: Expired due to Term

• Current Assignee: TEL Solar AG (OC Oerlikon Corporation AG)
• Original Assignee: Unaxis Balzers AG (Oerlikon USA, Inc. (Florida))
• Inventors: Elyaakoubi, Mustapha, Schmitt, Jacques, Perrin, Jerome
• Primary Examiner(s): Paschall, Mark
• Application Number:
  US09/360,247
• Time in Patent Office: 767 Days
• Field of Search: 219/121.52, 219/121.4, 219/121.41, 219/121.43, 219/121.48, 315/111.21, 315/111.31, 196/345, 196/646.1, 118/723.R, 118/723.I
• US Class Current: 219/121.43
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01J 37/32541 Shape

Abstract

A capacitively coupled RF plasma reactor allows treatment of large workpiece surfaces with an accurate control of ion bombardment onto the respective electrode surfaces and thus an adjacent workpiece, be it to a desired low or to a desired high level. The reactor includes a first and a second electrode arrangement mutually spaced and confining a plasma reaction volume, at lest one of the electrode arrangements comprising electrically mutually isolated sub-electrodes, a first group of the sub-electrodes being commonly connected to a first electric input, and a second group of the sub-electrodes being commonly connected to a second electric input. The reactor thus substitutes at least one of the two customarily used reactor electrodes by an array of sub-electrodes which, by way of their respective first and second electric inputs, may be independently and thus differently electrically operated, usually but not exclusively with RF voltages.

Claims

1. A method for manufacturing a workpiece based on a silicon wafer substrate or a flat display with a substrate, comprising:

(a) providing first and second extended electrode arrangements mutually and substantially constantly spaced and substantially enclosing a plasma reaction volume within a reactor chamber;

(b) subdividing said first of said electrode arrangements into electrically mutually isolated subelectrodes;

(c) commonly connecting a first group of said subelectrodes to a common first electric input;

(d) commonly connecting a second group of said subelectrodes to a second electric input independent of said first electric input; and

(e) introducing said substrate onto said second electrode arrangement;

(f) operatively connecting both said first and second electric inputs to one common Rf signal generator via respective signal adjusting unite;

(g) generating by said Rf signal generation an Rf plasma discharge within said plasma reaction volume; and

(h) controlling ion bombardment on and along said substrate by respective signal adjusting units operatively connected to said first and second electric inputs.

2. The method of claim 1, wherein subdividing includes shaping said subelectrodes as bars.

3. The method of claim 1, further comprising subdividing said first electrode arrangement into a two-dimensional pattern of said subelectrodes.

4. The method of claim 1, wherein subdividing comprises subdivision of said first electrode arrangements into one of frame-like and annular subelectrodes.

5. The method of claim 1, further comprising grouping of subelectrodes in at least one direction along said first electrode arrangement into a periodically alternating pattern.

6. The method of claim 1, further comprising providing said subelectrodes with surfaces pointing towards said substrate and being convexly or concavely enlarged.

7. The method of claims 1, further providing said first and second electrode arrangements comprised of planar parallel electrode arrangements.

8. The method of claim 1, further comprising applying electric signals to said first and second electric inputs via said signal adjusting units, and mutually controlling said signals with respect to at least one amplitude phasing and signal shapes.

9. The method of claim 1, further comprising spacing neighboring subelectrodes less than by dark space distance of said plasma generated in said plasma reaction volume.

10. The method of claim 1, further comprising controlling temperature of at least one of said first and second electrode arrangements.

11. The method of claim 1, further comprising inletting gas between at least a part of said subelectrodes.

12. The method of claim 11, further comprising providing a gas distribution chamber on a backside of said first electrode arrangement, and inletting gas into said plasma reaction space from between at least some of said subelectrodes.

13. The method of claim 1, further comprising shielding at least some of said subelectrode, at least one of between adjacent ones of said subelectrodes and behind said subelectrodes.

14. The method of claim 1, further comprising providing said first electrode arrangement with a corrugated surface pattern, thereby considerably enlarging a surface of said first electrode arrangement exposed to said plasma.

15. The method of claim 1, further comprising separating neighboring ones of said subelectrodes by intermediate gaps, and providing said subelectrodes with surfaces pointing towards said substrate, said surfaces being convexly enlarged, thereby abruptly enlarging a mutual distance between neighboring subelectrode surfaces beyond said gaps.

16. The method of claim 1, further comprising electrically operating said second electrode via an impedance matching network.

17. The method of claim 1, further comprising providing at least one third electrode arrangement bordering at least one of said first and of said second electrode arrangements.

18. The method of claim 17, further comprising providing said third electrode arangement substantially all around at least one of said first and of said second electrode arrangements.

19. The method of claim 1, further comprising subdividing said first electrode arrangement into more than two groups of said subelectrodes.

20. The method of claim 1, further comprising operating at least one of said first and second inputs and of said second electrode arrangements at a reference potential via at least one of a passive impedance matching network and of an active signal generator, and further generating with said active generator (i) an AC signal of a predetermined or adjustable frequency spectrum, said spectrum being constant in time or varying in time with respect to at least one of spectral amplitudes, frequency distribution and phasing, or (ii) a DC signal.

21. The method of claim 17, further comprising operating said third electrode arrangement at a reference potential via at least one of a passive impedance matching network and of an active signal generator, and further generating with said active generator (i) an AC signal of a predetermined or adjustable frequency spectrum, said spectrum being constant in time or varying in time with respect to at least one of spectral amplitudes, frequency distribution and phasing, or (ii) a DC signal.

22. The method of claim 1, further comprising electrically operating two of said first and said second electric inputs and of said second electrode arrangement with equal electric signals.

23. The method of claim 17, further comprising electrically driving at least two of said third electrode, said first, and said second inputs, and said second electrode arrangement with equal electric signals.

24. The method of claim 1, further comprising selecting a distance between subelectrodes of the same group at most equally to a distance between said first and said second electrode arrangements.

43. The method of claim 20, further comprising electrically operating said two of first and second electric inputs and of second electrode arrangements with equal electric signals.

25. A method for manufacturing a workpiece based on a silicon wafer substrate or a flat display with a substrate, comprising

(a) providing therein a first and a second extended electrode arrangement mutually and substantially constantly spaced and substantially enclosing a plasma reaction volume within a reactor chamber;

(b) subdividing said first electrode arrangement into electrically mutually isolated subelectrodes;

(c) connecting commonly a first group of said subelectrodes to a first electric input;

(d) connecting commonly a second group of said subelectrodes to a second electric input, said first and said second electric inputs being independent of each other;

(e) providing slits between said subelectrodes of said first electrode arrangement with a width smaller than a dark space distance of a plasma to be generated in said plasma reaction volume;

(f) introducing said substrate into said reactor and onto said second electrode arrangement;

(g) generating in said plasma reaction volume an Rf plasma with said first and second electrode arrangements; and

(h) feeding a gas through said slits between said subelectrodes into said plasma reaction volume.

26. The method of claim 25, further comprising forming said subelectrodes by subelectrode bars.

27. The method of claim 25, further comprising subdividing said first electrode arrangement into a two-dimensional pattern of subelectrodes.

28. The method of claim 25, further comprising subdividing said first electrode arrangement into one of a frame-like and of an annular subelectrode pattern.

29. The method of claim 25, further comprising arranging said subelectrodes of said groups in a periodically alternating pattern in at least one direction along said first electrode arrangement.

30. The method of claim 25, further comprising forming said subelectrodes with surfaces pointing towards said second electrode arrangement, which surfaces are convexly or concavely enlarged.

31. The method of claim 25, further comprising arranging said first and second electrode arrangements substantially planar and mutually parallel.

32. The method of claim 25, further comprising mutually controlling electric signals applied to said first and second electric inputs with respect to at least one of amplitude, phasing and signal shapes.

33. The method of claim 25, further comprising temperature-controlling at least one of said first and said second electrode arrangements.

34. The method of claim 25, further comprising shielding at least one of between adjacent subelectrodes and behind subelectrodes.

35. The method of claim 25, further comprising providing said first electrode arrangement with a corrugated surface pattern to enlarge a surface of the first electrode arrangement exposed to said plasma.

36. The method of claim 25, further comprising providing surfaces of said subelectrodes pointing towards said first electrode arrangement, which surfaces are convely enlarged, whereby a mutual distance of said surfaces of said subelectrode beyond said gaps are abruptly enlarged.

37. The method of claim 25, further comprising electrically feeding said second electrode arrangement via an impedance-matching network.

38. The method of claim 25, further comprising providing at least one third electrode arrangement bordering at least one of said first and of said second electrode arrangements.

39. The method of claim 38, further comprising providing said third electrode arrangement all around at least one of said first and of said second electrode arrangements.

40. The method of claim 25, further comprising subdividing said first electrode arrangement into more than two groups of subelectrodes.

41. The method of claim 25, further comprising operating at least one of said first and of said second electrode arrangements at a reference potential via at least one of a passive impedance matching network and of an active signal generator and further generating with said signal generator (i) an AC signal of a predetermined or adjustable frequency spectrum, said spectrum being constant in time or varying in time with respect to at least one of spectral amplitudes, frequency distribution and phasing, or (ii) a DC signal.

42. The method of claim 38, further comprising operating said third electrode arrangement at a reference potential via at least one of a passive impedance matching network and of an active signal generator and further generating with said active generator (i) an AC signal of a predetermined or adjustable frequency spectrum, said spectrum being constant in time or varying in time with respect to at least one of spectral amplitudes, frequency distribution and phasing, or (ii) a DC signal.

44. The method of claim 38, further comprising electrically driving at least two of said third electrode arrangement, said first and said second inputs, and said second electrode arrangement with equal electric signals.

45. The method of claim 25, further comprising selecting a distance between subelectrodes of the same group to be at most equal to a distance of said first and second electrode arrangements.