Methods of etching silicon nitride substantially selectively relative to an oxide of aluminum

• US 7,030,034 B2
• Filed: 09/18/2003
• Issued: 04/18/2006
• Est. Priority Date: 09/18/2003
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Li, Li, Fucsko, Janos, Torek, Kevin J., Waldo, Grady S.
• Primary Examiner(s): Norton, Nadine G.
• Assistant Examiner(s): GEORGE, PATRICIA ANN
• Application Number:
  US10/664,738
• Publication Number:
  US 20050061768A1
• Time in Patent Office: 943 Days
• Field of Search: 438/745, 438/747, 438/749, 438/750, 438/757
• US Class Current: 438/757
• CPC Class Codes: C09K 13/08 containing a fluorine compound
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/76224 using trench refilling with dielectric materials trench filling with polycristalline silicon H01L21/763; together with vertical isolation, e.g. trench refilling in a SOI substrate H01L21/76264

Abstract

A method of etching silicon nitride substantially selectively relative to an oxide of aluminum includes providing a substrate comprising silicon nitride and an oxide of aluminum. The silicon nitride and the oxide is exposed to an etching solution comprising HF and an organic HF solvent under conditions effective to etch the silicon nitride substantially selectively relative to the oxide. Other aspects and implementations are contemplated.

Claims

1. A method of etching silicon nitride substantially selectively relative to an oxide of aluminum, comprising:

providing a substrate comprising silicon nitride and an oxide of aluminum; and

exposing the silicon nitride and the oxide to an etching solution comprising HF and an organic HF solvent under conditions effective to etch the silicon nitride substantially selectively relative to the oxide.

2. The method of claim 1 comprising providing the substrate to comprise an oxide of silicon and an oxide of aluminum, with the exposing being effective to etch the silicon nitride substantially selectively relative to each of said oxides.

3. The method of claim 1 wherein the etching solution comprises from 0.1% to 50% by weight water.

4. The method of claim 1 wherein the etching solution comprises from 0.1% to 15% by weight water.

5. The method of claim 1 wherein the etching solution comprises from 0.1% to 5% by weight water.

6. The method of claim 1 wherein the etching solution comprises from 0.1% to 1.0% by weight water.

7. The method of claim 1 wherein the etching solution has from 0% to less than 0.1% by weight water.

8. The method of claim 1 wherein the etching solution comprises from 0.01% to 50% by weight HF.

9. The method of claim 1 wherein the etching solution comprises from 0.1% to 15% by weight HF.

10. The method of claim 1 wherein the etching solution comprises from 1% to 5% by weight HF.

11. The method of claim 1 wherein the etching solution consists essentially of from 0.01% to 50% by weight HF, organic HF solvent, and from 0.1% to 50% by weight water.

12. The method of claim 1 wherein the etching solution consists essentially of from 0.1% to 15% by weight HF, organic HF solvent, and from 0.1% to 10% by weight water.

13. The method of claim 1 wherein the etching solution consists essentially of HF and organic HF solvent.

14. The method of claim 1 wherein the conditions comprise a temperature of at least 60°

C.

15. The method of claim 1 wherein the conditions comprise a temperature of from 70°

C. to 90°

C.

16. The method of claim 1 wherein the etching solution comprises 0% by weight water.

17. The method of claim 1 wherein the organic HF solvent comprises an alcohol.

18. The method of claim 17 wherein the alcohol is aliphatic.

19. The method of claim 17 wherein the alcohol is alicyclic.

20. The method of claim 17 wherein the organic HF solvent comprises ethanol.

21. The method of claim 17 wherein the alcohol is aromatic.

22. The method of claim 17 wherein the alcohol is heterocyclic.

23. The method of claim 1 wherein the organic HF solvent comprises a polyol.

24. The method of claim 23 wherein the polyol has a boiling point of at least 150°

C.

25. The method of claim 23 wherein the polyol comprises a glycol.

26. The method of claim 23 wherein the polyol comprises a glycerol.

27. The method of claim 23 wherein the polyol comprises a carboxylic acid.

28. A method of etching silicon nitride substantially selectively relative to aluminum oxide, comprising:

providing a substrate comprising silicon nitride and a densified aluminum oxide; and

exposing the silicon nitride and the densified aluminum oxide to an etching solution comprising HF and an organic HF solvent under conditions effective to etch the silicon nitride substantially selectively relative to the densified aluminum oxide.

29. The method of claim 28 wherein the etching solution comprises from 0.1% to 50% by weight water.

30. The method of claim 28 wherein the etching solution comprises from 0.1% to 15% by weight water.

31. The method of claim 28 wherein the etching solution comprises from 0.1% to 5% by weight water.

32. The method of claim 28 wherein the etching solution comprises no more than 1% by weight water.

33. The method of claim 28 wherein the etching solution has from 0% to less than 0.1% by weight water.

34. The method of claim 28 wherein the etching solution comprises from 0.01% to 50% by weight HF.

35. The method of claim 28 wherein the etching solution comprises from 0.1% to 15% by weight HF.

36. The method of claim 28 wherein the etching solution comprises from 1% to 5% by weight HF.

37. The method of claim 28 wherein the etching solution consists essentially of from 0.01% to 50% by weight HF, organic HF solvent, and from 0.1% to 50% by weight water.

38. The method of claim 28 wherein the etching solution consists essentially of from 0.1% to 15% by weight HF, organic HF solvent, and from 0.1% to 10% by weight water.

39. The method of claim 28 wherein the etching solution consists essentially of HF and organic HF solvent.

40. The method of claim 28 wherein the conditions comprise a temperature of at least 60°

C.

41. The method of claim 28 wherein the conditions comprise a temperature of from 70°

C. to 90°

C.

42. The method of claim 28 wherein the etching solution comprises 0% by weight water.

43. The method of claim 28 wherein the organic HF solvent comprises an alcohol.

44. The method of claim 43 wherein the alcohol is aliphatic.

45. The method of claim 43 wherein the alcohol is alicyclic.

46. The method of claim 43 wherein the organic HF solvent comprises ethanol.

47. The method of claim 43 wherein the alcohol is aromatic.

48. The method of claim 43 wherein the alcohol is heterocyclic.

49. The method of claim 28 wherein the organic HF solvent comprises a polyol.

50. The method of claim 49 wherein the polyol has a boiling point of at least 150°

C.

51. The method of claim 49 wherein the polyol comprises a glycol.

52. The method of claim 49 wherein the polyol comprises a glycerol.

53. The method of claim 49 wherein the polyol comprises a carboxylic acid.