Method of etching a magnetic material

• US 6,911,346 B2
• Filed: 03/21/2003
• Issued: 06/28/2005
• Est. Priority Date: 04/03/2002
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Jain, Mohit, Kumar, Ajay, Chen, Xiaoyi, Ying, Chentsau
• Primary Examiner(s): Lee, Hsien Ming
• Application Number:
  US10/394,464
• Publication Number:
  US 20030219984A1
• Time in Patent Office: 830 Days
• Field of Search: 438/3, 438/710, 438/694, 438/706, 438/689, 257/296, 257/421, 257/414
• US Class Current: 438/3
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C23F 4/00 Processes for removing metallic material from surfaces, not provided for in group C23F1/00 or C23F3/00
• CPC Class Codes: G11B 5/653 containing Fe or Ni containing Co G11B5/656; containing inorganic, non-oxide compounds of Si, N, P, B, H or C G11B5/657; containing oxygen G11B5/658
• CPC Class Codes: G11B 5/656 containing Co containing inorganic, non-oxide compounds of Si, N, P, B, H or C G11B5/657; containing oxygen G11B5/658
• CPC Class Codes: G11B 5/855 Coating only part of a support with a magnetic layer
• CPC Class Codes: H01F 41/308 lift-off processes, e.g. ion milling, for trimming or patterning
• CPC Class Codes: H03J 2200/36 Circuit arrangements for, e.g. increasing the tuning range, linearizing the voltage-capacitance relationship, lowering noise, constant slope in different bands
• CPC Class Codes: H10N 50/01 Manufacture or treatment

Abstract

A method of etching a magnetic material (e.g., nickel-iron alloy (NiFe), cobalt-iron alloy (CoFe), and the like) using a gas mixture comprising a hydrogen halide gas and a fluorocarbon-containing gas is disclosed. The method provides high etch selectivity for the magnetic materials over non-magnetic dielectric materials, such as aluminum oxide (Al₂O₃) and the like, as well as to photoresist.

Claims

1. A method of etching a magnetic material, comprising:

(a) providing a substrate having a layer of a magnetic material thereon;

(b) forming a patterned mask on the layer of magnetic material; and

(c) etching the layer of magnetic material using a gas mixture comprising a hydrogen halide gas and a fluorocarbon-containing gas.

2. The method of claim 1 wherein the fluorocarbon-containing gas is selected from the group consisting of carbon tetrafluoride (CF₄), trifluoromethane (CHF₃), difluoromethane (CH₂F₂) and fluoromethane (CH₃F).

3. The method of claim 1 wherein the magnetic material comprises at least one of NiFe and CoFe.

4. The method of claim 1 wherein step (c) provides an etch selectivity for the magnetic material over a dielectric material of about 15:

1.

5. The method of claim 1 wherein step (c) provides an etch selectivity for the magnetic material over a photoresist patterned mask of about 0.2:

1.

6. The method of claim 1 wherein the gas mixture of step (c) comprises the hydrogen halide gas and the fluorocarbon-containing gas at a hydrogen halide:

fluorocarbon-containing gas flow ratio within a range of about 1;

1 to 8;

1.

7. The method of claim 6 wherein the gas mixture further comprises a diluent gas.

8. The method of claim 7 wherein the diluent gas comprises one or more gases selected from the group consisting of argon (Ar), helium (He) and neon (Ne).

9. The method of claim 6 wherein the fluorocarbon-containing gas is selected from the group consisting of carbon tetrafluoride (CF₄), trifluoromethane (CHF₃), difluoromethane (CH₂F₂) and fluoromethane (CH₃F).

10. The method of claim 6 wherein the magnetic material comprises at least one of NiFe and CoFe.

11. The method of claim 1 wherein the gas mixture further comprises a diluent gas.

12. The method of claim 11 wherein the diluent gas comprises one or more gases selected from the group consisting of argon (Ar), helium (He) and neon (Ne).

13. The method of claim 11 wherein the gas mixture of step (c) comprises the hydrogen halide and the diluent gas at a hydrogen halide to diluent gas flow ratio within a range of about 1:

1 to 8;

1.

14. The method of claim 1 wherein step (c) further comprises:

providing hydrogen bromide (HBr) and carbon tetrafluoride (CF₄) at an HBr;

CF₄ flow ratio within a range of about 1;

1 to 8;

1;

providing argon (Ar) at an HBr;

Ar flow ratio within a range of about 1;

1 to 8;

1;

maintaining the substrate at a temperature of about 15 to about 80 degrees Celsius;

applying a plasma power of about 200 W to about 3000 W;

applying a substrate bias power of about 50 W to about 300 W; and

maintaining a process chamber pressure within a range of about 5 mTorr to about 40 mTorr.

15. The method of claim 1 wherein the hydrogen halide gas is selected from the group consisting of hydrogen bromide (HBr), hydrogen chloride (HCl), and hydrogen fluoride (HF).

16. The method of claim 1 wherein the hydrogen halide gas comprises hydrogen bromide (HBr).

17. The method of claim 16 wherein the fluorocarbon-containing gas is selected from the group consisting of carbon tetrafluoride (OF₄), trifluoromethane (CHF₃), difluoromethane (CH₂F₂) and fluoromethane (CH₃F).

18. The method of claim 16, wherein the hydrogen bromide gas and the fluorocarbon-containing gas of the gas mixture of step (c) is provided at a hydrogen bromide:

fluorocarbon-containing gas flow ratio within a range of about 1;

1 to 8;

1.

19. A method of fabricating a magneto-resistive random access memory (MRAM) device, comprising:

(a) providing a substrate having a top electrode and a free magnetic layer formed on a film stack comprising a tunnel layer, one or more magnetic layers and a bottom electrode;

(b) forming a patterned mask on the top electrode;

(c) etching the top electrode; and

(d) etching the free magnetic layer using a gas mixture comprising a hydrogen halide gas and a fluorocarbon-containing gas.

20. The method of claim 19 wherein the hydrogen halide gas is selected from the group consisting of hydrogen bromide (HBr), hydrogen chloride (HCl) and hydrogen fluoride (HF).

21. The method of claim 19 wherein the fluorocarbon-containing gas is selected from the group consisting of carbon tetrafluoride (CF₄), trifluoromethane (CHF₃), difluoromethane (CH₂F₂) and fluoromethane (CH₃F).

22. The method of claim 19 wherein the magnetic material comprises at least one of NiFe and CoFe.

23. The method of claim 19 wherein step (d) provides an etch selectivity for the magnetic material over the tunnel layer of about 15:

1.

24. The method of claim 19 wherein step (d) provides an etch selectivity for the magnetic material over a photoresist patterned mask of about 0.2:

1.

25. The method of claim 19 wherein a protective film is formed on the tunnel layer during step (d).

26. The method of claim 25 wherein the tunnel layer comprises aluminum oxide (Al₂O₃) and the protective film comprises aluminum fluoride (AlF_x).

27. The method of claim 19 wherein the gas mixture of step (d) comprises the hydrogen halide and fluorocarbon-containing gas at a hydrogen halide:

fluorocarbon-containing gas flow ratio within a range of about 1;

1 to 8;

1.

28. The method of claim 19 wherein the gas mixture further comprises a diluent gas.

29. The method of claim 28 wherein the diluent gas comprises one or more gases selected from the group consisting of argon (Ar), helium (He) and neon (Ne).

30. The method of claim 28 wherein the gas mixture of step (d) comprises the hydrogen halide and diluent gas at a hydrogen halide:

diluent gas flow ratio within a range of about 1;

1 to 8;

1.

31. The method of claim 19 wherein step (d) further comprises:

providing hydrogen bromide (HBr) and carbon tetrafluoride (CF₄) at an HBr;

CF₄ flow ratio within a range of about 1;

1 to 8;

1;

providing argon (Ar) at an HBr;

Ar flow ratio within a range of about 1;

1 to 8;

1;

maintaining the substrate at a temperature of about 15 to about 80 degrees Celsius;

applying a plasma power of about 200 W to about 3000 W;

applying a substrate bias power of about 50 W to about 300 W; and

maintaining a process chamber pressure within a range of about 5 mTorr to about 40 mTorr.

32. The method of claim 19 wherein the hydrogen halide gas comprises hydrogen bromide (HBr).

33. The method of claim 32 wherein the fluorocarbon-containing gas is selected from the group consisting of carbon tetrafluoride (CF₄), trifluoromethane (CHF₂), difluoromethane (CH₂F₂) and fluoromethane (CH₃F).

34. The method of claim 33 wherein the hydrogen bromide gas and the fluorocarbon-containing gas of the gas mixture of step (c) is provided at a hydrogen bromide:

fluorocarbon-containing gas flow ratio within a range of about 1;

1 to 8;

1.

35. A computer-readable medium containing instructions that when executed by a computer causes a semiconductor wafer processing system to etch a magnetic material using a method comprising:

(a) forming a patterned mask on a layer of magnetic material disposed on a substrate; and

(b) etching the layer of magnetic material using a gas mixture comprising a hydrogen halide gas and a fluorocarbon-containing gas.

36. The computer-readable medium of claim 35 wherein the fluorocarbon-containing gas is selected from the group consisting of carbon tetrafluoride (CF₄), trifluoromethane (CHF₃), difluoromethane (CH₂F₂) and fluoromethane (CH₃F).

37. The computer-readable medium of claim 35 wherein the magnetic material comprises at least one of NiFe and CoFe.

38. The computer readable medium of claim 35 wherein the hydrogen halide gas is selected from the group consisting of hydrogen bromide (HBr), hydrogen chloride (HCl), and hydrogen fluoride (HF).