Methods for etching doped oxides in the manufacture of microfeature devices

• US 8,513,086 B2
• Filed: 07/02/2012
• Issued: 08/20/2013
• Est. Priority Date: 09/01/2005
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Rana, Niraj
• Primary Examiner(s): Rizkallah, Kimberly
• Assistant Examiner(s): HENRY, CALEB E
• Application Number:
  US13/540,510
• Publication Number:
  US 20120276748A1
• Time in Patent Office: 414 Days
• Field of Search: 438/724, 438/738, 438/744, 438/757, 438/381, 257/E21.265, 257/E21.215, 257/E21.309
• US Class Current: 438/381
• CPC Class Codes: C09K 13/08 containing a fluorine compound
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 28/91 made by depositing layers, e.g. by depositing alternating conductive and insulating layers
• CPC Class Codes: H10B 12/033 the capacitor extending over the transistor

Abstract

Methods for selectively etching doped oxides in the manufacture of microfeature devices are disclosed herein. An embodiment of one such method for etching material on a microfeature workpiece includes providing a microfeature workpiece including a doped oxide layer and a nitride layer adjacent to the doped oxide layer. The method include selectively etching the doped oxide layer with an etchant comprising DI:HF and an acid to provide a pH of the etchant such that the etchant includes (a) a selectivity of phosphosilicate glass (PSG) to nitride of greater than 250:1, and (b) an etch rate through PSG of greater than 9,000 Å/minute.

Claims

1. A method for etching material on a microfeature workpiece, the method comprising:

forming a framework on a microfeature workpiece, the framework including a conductive material, a doped oxide material, and a nitride material adjacent to the doped oxide material and the conductive material; and

selectively etching the doped oxide material over the conductive and nitride materials of the framework with an etchant including DI;

HF and an acid to provide a pH of the etchant such that the etchant includes (a) a selectivity of phosphosilicate glass (PSG) to nitride of greater than 250;

1, and (b) an etch rate through PSG of greater than 9,000 Å

/minute.

2. The method of claim 1 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material a with an etchant including a pH below about 2.0.

3. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant including DI;

HF;

HNO₃, the etchant having a ratio of DI to HF to HNO₃ of approximately 2;

1;

X to approximately 100;

1;

X, wherein X is a value from 0.0001 to 5.0.

4. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant including DI;

HF;

HNO₃, the etchant having a ratio of DI to HF to HNO₃ of approximately 2-30;

1;

0.5-3.0.

5. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant including DI;

HF;

HNO₃,the etchant having a ratio of DI to HF to HNO₃ of approximately 10;

1;

1.0-2.0.

6. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant including DI;

HF;

HCl, the etchant having a ratio of DI to HF to HCl of approximately 2;

1;

X to approximately 100;

1;

X, wherein X is a value from 0.0001 to 5.0.

7. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant including DI;

HF;

HCl, the etchant having a ratio of DI to HF to HCl of approximately 2-30;

1;

0.5-3.0.

8. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant including DI;

HF;

HCl, the etchant having a ratio of DI to HF to HCl of approximately 10;

1;

1.0-2.0.

9. The method of claim 2 wherein selectively etching the doped oxide material a with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant including DI;

HF;

H₂SO₄, the etchant having a ratio of DI to HF to H₂SO₄ of approximately 2;

1;

X to approximately 100;

1;

X, wherein X is a value from 0.0001 to 5.0.

10. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant including DI;

HF;

H₂SO₄, the etchant having a ratio of DI to HF to H₂SO₄ of approximately 2-30;

1;

0.5-3.0.

11. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant including DI;

HF;

H₂SO₄, the etchant having a ratio of DI to HF to H₂SO₄ of approximately 10;

1;

1.0-2.0.

12. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant including DI;

HF;

H₃SO₄, the etchant having a ratio of DI to HF to H₃SO₄ of approximately 2;

1;

X to approximately 100;

1;

X, wherein X is a value from 0.0001 to 5.0.

13. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant including DI;

HF;

H₃SO₄, the etchant having a ratio of DI to HF to H₃SO₄ of approximately 2-30;

1;

0.5-3.0.

14. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant including DI;

HF;

H₃SO₄, the etchant having a ratio of DI to HF to H₃PO₄ of approximately 10;

1;

1.0-2.0.

15. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant having a selectivity of PSG to nitride of greater than about 300;

1.

16. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant having a selectivity of PSG to nitride of greater than about 400;

1.

17. The method of claim 2 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant having an etch rate of over about 9,500 Å

/minute through the doped oxide material.

18. The method of claim 1 wherein selectively etching the doped oxide material with an etchant including DI:

HF and an acid includes etching the doped oxide material with an etchant that generally includes no acetic acid.

19. The method of claim 1 wherein forming the framework on the microfeature workpiece comprises forming a microfeature workpiece having a PSG material and/or borophosphosilicate glass (BPSG) material.

21. The method of claim 1 wherein the selectivity of PSG to the conductive material is greater than 1000:

1.

22. The method of claim 1 wherein the conductive material comprises Titanium Nitride (TiN).

23. The method of claim 1 wherein the conductive material comprises polysilicon.

20. The method of claim wherein the conductive material comprises a first conductive material, and wherein the method further comprises:

depositing the first conductive material over at least a portion of the doped oxide material before etching the doped oxide material, the first conductive material including Titanium Nitride (TiN);

depositing a second conductive material over at least a portion of the first conductive material before etching the doped oxide material, the second conductive material including polysilicon; and

wherein selectively etching the doped oxide material includes using an etchant that etches up to and generally not into the first and second conductive materials.