Method of plasma etching of high-K dielectric materials

• US 20030211748A1
• Filed: 05/09/2002
• Published: 11/13/2003
• Est. Priority Date: 05/09/2002
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Kumar, Ajay, Nallan, Padmapani, Jin, Guangxiang
• Granted Patent: US 7,094,704 B2
• Time in Patent Office: Days
• US Class Current: 438/709
• CPC Class Codes: H01L 21/31122 of layers not containing Si, e.g. PZT, Al2O3

Abstract

A method of etching high dielectric constant materials using a halogen gas, a reducing gas and an etch rate control gas chemistry.

Claims

1. A method of plasma etching a layer of dielectric material having a dielectric constant that is greater than 4 comprising the steps of:

exposing said dielectric material layer to a plasma comprising a reducing gas, a halogen containing gas and an etch rate control gas.

2. The method of claim 1 wherein the dielectric material is at least one of HfO₂, ZrO₂, Al₂O₃, BST, PZK, ZrSiO₂, HfSiO₂, and TaO₂

3. The method of claim 1 wherein the dielectric material is HfO₂.

4. The method of claim 1 wherein the halogen containing gas comprises a chlorine containing gas.

5. The method of claim 1 wherein the reducing gas comprises carbon monoxide.

6. The method of claim 1 wherein halogen gas comprises chlorine and the reducing gas comprises carbon monoxide.

7. The method of claim 4 wherein said chlorine containing gas is Cl₂.

8. The method of claim 1 wherein the etch rate control gas is argon.

9. The method of claim 1 wherein the etch rate control gas is oxygen.

10. The method of claim 1 wherein the etch rate control gas comprises at least one of argon and oxygen.

11. The method of claim 6 wherein said exposing step further comprises the step of:

supplying 20 to 300 sccm of Cl₂ and 2 to 200 sccm of CO.

12. The method of claim 1 further comprising the step of:

maintaining a gas pressure of between 2-100 mTorr.

13. The method of claim 6 further comprising the step of:

maintaining a gas pressure of 4 mTorr.

14. The method of claim 1 further comprising the step of:

applying a bias power to a cathode pedestal of 0 to 100 W.

15. The method of claim 6 further comprising the step of:

applying a bias power to a cathode pedestal of 0 W.

16. The method of claim 1 further comprising the step of:

applying an inductive source power to an inductively coupled antenna of 200 to 2500 W.

17. The method of claim 6 further comprising the step of:

applying an inductive source power to an inductively coupled antenna of 1100 W.

18. The method of claim 1 further comprising the step of:

maintaining a workpiece containing said hafnium-oxide layer at a temperature between 100 to 500 degrees Celsius.

19. The method of claim 6 further comprising the step of:

maintaining a workpiece containing said hafnium-oxide layer at a temperature of 350 degrees Celsius.

20. A method for plasma etching a workpiece having a layer of hafnium-oxide comprising the steps of:

supplying between 20 to 300 sccm of chlorine, between 2 to 200 sccm of carbon monoxide between 1 to 100 sccm of an etch rate control gas;

maintaining a gas pressure of between 2-100 mTorr;

applying a bias power to a cathode pedestal of between 0 to 100 W;

applying power to an inductively coupled antenna of between 200 to 2500 W to produce a plasma containing said chlorine gas and said sulfur dioxide gas;

maintaining said workpiece at a temperature between 100 and 500 degrees Celsius.

21. The method of claim 20 wherein the etch rate control gas comprises at least one of argon and oxygen.

22. A computer-readable medium containing software that when executed by a computer causes an etch reactor to plasma etch a layer of dielectric material having a dielectric constant that is greater than 4 using a method comprising:

exposing said dielectric material layer to a plasma comprising a reducing gas, a halogen containing gas and an etch rate control gas.

23. A computer-readable medium of claim 22 wherein the dielectric material is at least one of HfO₂, ZrO₂, Al₂O₃, BST, PZK, ZrSiO₂, HfSiO₂, and TaO₂

24. A computer-readable medium of claim 22 wherein the dielectric material is HfO₂.

25. A computer-readable medium of claim 22 wherein the halogen containing gas comprises a chlorine containing gas.

26. A computer-readable medium of claim 22 wherein the reducing gas comprises carbon monoxide.

27. A computer-readable medium of claim 22 wherein halogen gas comprises chlorine and the reducing gas comprises carbon monoxide.

28. A computer-readable medium of claim 25 wherein said chlorine containing gas is Cl₂.

29. The computer-readable medium of claim 22 wherein the etch rate control gas is argon.

30. The computer-readable medium of claim 22 wherein the etch rate control gas is oxygen.

31. The computer-readable medium of claim 22 wherein the etch rate control gas comprises at least one of argon and oxygen.

32. A computer-readable medium of claim 27 wherein said exposing step further comprises the step of:

supplying 20 to 300 sccm of Cl₂ and 2 to 200 sccm of CO.

33. A computer-readable medium of claim 22 further comprising the step of:

maintaining a gas pressure of between 2-100 mTorr.

34. A computer-readable medium of claim 22 further comprising the step of:

maintaining a gas pressure of 4 mTorr.

35. A computer-readable medium of claim 22 further comprising the step of:

applying a bias power to a cathode pedestal of 0 to 100 W.

36. The method of claim 35 further comprising the step of:

applying a bias power to a cathode pedestal of 0 W.

37. A computer-readable medium of claim 22 further comprising the step of:

applying an inductive source power to an inductively coupled antenna of 200 to 2500 W.

38. A computer-readable medium of claim 37 further comprising the step of:

applying an inductive source power to an inductively coupled antenna of 1100 W.

39. A computer-readable medium of claim 22 further comprising the step of:

maintaining a workpiece containing said hafnium-oxide layer at a temperature between 100 to 500 degrees Celsius.

40. A computer-readable medium of claim 39 further comprising the step of:

maintaining a workpiece containing said hafnium-oxide layer at a temperature of 350 degrees Celsius.

41. A computer-readable medium containing software that when executed by a computer causes a etch reactor to plasma etch a workpiece having a layer of hafnium-oxide using a method comprising:

supplying between 20 to 300 sccm of chlorine, between 2 to 200 sccm of carbon monoxide between 1-100 sccm of an etch rate control gas;

maintaining a gas pressure of between 2-100 mTorr;

applying a bias power to a cathode electrode of between 0 to 100 W;

applying power to an inductively coupled antenna of between 200 to 2500 W to produce a plasma containing said chlorine gas and said sulfur dioxide gas;

maintaining said workpiece at a temperature between 100 and 500 degrees Celsius.

42. The computer readable medium of claim 41 wherein said etch rate control gas comprises at least one of an argon and oxygen.