Electrode designs for controlling uniformity profiles in plasma processing reactors

• US 5,716,485 A
• Filed: 06/07/1995
• Issued: 02/10/1998
• Est. Priority Date: 06/07/1995
• Status: Expired due to Term

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Varian Associates, Inc. (Siemens AG)
• Inventors: Heller, Carol M., Li, Lumin, Salimian, Siamak
• Primary Examiner(s): Tsai, Jey
• Assistant Examiner(s): CHANG, JONI YUK YING
• Application Number:
  US08/476,966
• Time in Patent Office: 979 Days
• Field of Search: 156/345, 216/67, 216/68, 216/71, 118/723 E, 118/723 ER, 118/723 I, 118/723 IR, 118/723 MP, 204/298.06, 204/298.34, 204/298.39
• US Class Current: 156/345.43
• CPC Class Codes: H01J 37/32009 Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources plasma generation in general H05H1/24
• CPC Class Codes: H01J 37/32541 Shape

Abstract

Electrode designs for reducing the problem of non-uniform etch in large diameter substrates are presented. The electrode opposite the substrate being etched in a plasma reactor can be tailored as to its shape so as to control the uniformity of the etching across the substrate. This is achieved with a number of generally dome-shaped electrode structures including generally cone-shaped electrodes, generally pyramidally-shaped electrodes and generally hemispherically-shaped electrodes. It is believed that non-uniformity of etching is due, at least in part, to excess ion density at the center of the reactor. The dome-shaped electrodes serve to disperse the high concentration of ions from the center of the reactor out toward the periphery of the substrate and thereby even out the ion density distribution across the substrate being etched. The electrodes are useable in diode plasma reactors, triode plasma reactors and ICP plasma reactors.

Claims

1. A plasma reactor for etching a substrate, said reactor comprising:

.

a first powered electrode adapted to support the substrate, said first powered electrode connected to a source of RF energy;

a second electrode disposed at a distance from said first powered electrode, said second electrode having a generally conical shape, an apex of said conical shape closer to said first electrode than a base of said conical shape.

2. A reactor according to claim 1 wherein the reactor is a diode type reactor and said second electrode is grounded.

3. A reactor according to claim 1 wherein the reactor is a triode type reactor and said second electrode is a powered electrode connected to a source of RF energy.

4. A reactor according to claim 1 wherein the reactor is an inductively coupled type type reactor and said second electrode is connected to a source of RF energy.

5. A plasma reactor for etching a substrate, said reactor comprising:

a first powered electrode adapted to support the substrate, said first powered electrode connected to a source of RF energy;

second electrode disposed at a distance from said first powered electrode, said second electrode having a generally pyramidal shape, an apex of said pyramidal shape closer to said first powered electrode than a base of said pyramidal shape.

6. A reactor according to claim 5 wherein the reactor is a diode type reactor and said second electrode is grounded.

7. A reactor according to claim 5 wherein the reactor is a triode type reactor and said second electrode is a powered electrode connected to a source of RF energy.

8. A reactor according to claim 5 wherein the reactor is an inductively coupled type type reactor and said second electrode is connected to a source of RF energy.

9. A plasma reactor for etching, a substrate, said reactor comprising:

a first powered electrode adapted to support the substrate, said first powered electrode connected to a source of RF energy;

a second electrode disposed at a distance from said first powered electrode, said second grounded electrode having a generally truncated conical shape, an apex of said truncated conical shape closer to said first powered electrode than a base of said truncated conical shape.

10. A reactor according to claim 9 wherein the reactor is a diode type reactor and said second electrode is grounded.

11. A reactor according to claim 9 wherein the reactor is a triode type reactor and said second electrode is a powered electrode connected to a source of RF energy.

12. A reactor according to claim 9 wherein the reactor is an inductively coupled type type reactor and said second electrode is connected to a source of RF energy.

13. A plasma reactor for etching a substrate, said reactor comprising:

a first powered electrode adapted to support the substrate, said first powered electrode connected to a source of RF energy;

a second electrode disposed at a distance from said first powered electrode, said second electrode having a generally truncated pyramidal shape, an apex of said truncated pyramidal shape closer to said first powered electrode than a base of said truncated pyramidal shape.

14. A reactor according to claim 13 wherein the reactor is a diode type reactor and said second electrode is grounded.

15. A reactor according to claim 13 wherein the reactor is a triode type reactor and said second electrode is a powered electrode connected to a source of RF energy.

16. A reactor according to claim 13 wherein the reactor is an inductively coupled type type reactor and said second electrode is connected to a source of RF energy.

17. A plasma reactor for etching a substrate, said reactor comprising:

a first powered electrode adapted to support the substrate, said first powered electrode connected to a source of RF energy;

a second electrode disposed at a distance from said first powered electrode, said second electrode having a generally truncated hemispherical shape, an apex of said truncated hemispherical shape closer to said first electrode than a base of said truncated hemispherical shape.

18. A reactor according to claim 17 wherein the reactor is a diode type reactor and said second electrode is grounded.

19. A reactor according to claim 17 wherein the reactor is a triode type reactor and said second electrode is a powered electrode connected to a source of RF energy.

20. A reactor according to claim 17 wherein the reactor is an inductively coupled type type reactor and said second electrode is connected to a source of RF energy.

21. A plasma reactor for etching a substrate, said reactor comprising:

a first powered electrode adapted to support the substrate, said first powered electrode connected to a source of RF energy;

a second electrode disposed at a distance from said first powered electrode, said second electrode having a generally folded conical shape, an apex of said folded conical shape closer to said first electrode than a base of said folded conical shape.

22. A reactor according to claim 21 wherein the reactor is a diode type reactor and said second electrode is grounded.

23. A reactor according to claim 21 wherein the reactor is a triode type reactor and said second electrode is a powered electrode connected to a source of RF energy.

24. A reactor according to claim 21 wherein the reactor is an inductively coupled type type reactor and said second electrode is connected to a source of RF energy.

25. A plasma reactor for etching a substrate, said reactor comprising:

a first powered electrode adapted to support the substrate, said first powered electrode connected to a source of RF energy;

a second electrode disposed at a distance from said first powered electrode, said second electrode having a generally folded pyramidal shape, an apex of said folded pyramidal shape closer to said first electrode than a base of said folded pyramidal shape.

26. A reactor according to claim 25 wherein the reactor is a diode type reactor and said second electrode is grounded.

27. A reactor according to claim 25 wherein the reactor is a triode type reactor and said second electrode is a powered electrode connected to a source of RF energy.

28. A reactor according to claim 25 wherein the reactor is an inductively coupled type type reactor and said second electrode is connected to a source of RF energy.

29. A plasma reactor for etching a substrate, said reactor comprising:

a first powered electrode adapted to support the substrate, said first powered electrode connected to a source of RF energy;

a second electrode disposed at a distance from said first powered electrode, said second electrode having a generally folded hemispherical shape, an apex of said folded hemispherical shape closer to said first electrode than a base of said folded hemispherical shape.

30. A reactor according to claim 29 wherein the reactor is a diode type reactor and said second electrode is grounded.

31. A reactor according to claim 29 wherein the reactor is a triode type reactor and said second electrode is a powered electrode connected to a source of RF energy.

32. A reactor according to claim 29 wherein the reactor is an inductively coupled type type reactor and said second electrode is connected to a source of RF energy.