Selective etching of oxides to metal nitrides and metal oxides

• US 8,119,537 B2
• Filed: 06/17/2005
• Issued: 02/21/2012
• Est. Priority Date: 09/02/2004
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Shea, Kevin R., Torek, Kevin J.
• Primary Examiner(s): Vinh, Lan
• Application Number:
  US11/155,809
• Publication Number:
  US 20060046513A1
• Time in Patent Office: 2,440 Days
• Field of Search: 438/706, 438/710, 438/714, 438/754, 438/756, 438/757, 438/740, 438/745, 438/723, 216/67, 216/72, 216/73, 216/75, 216/79, 216/99, 216/100
• US Class Current: 438/756
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/76802 by forming openings in dielectrics
• CPC Class Codes: H01L 21/76838 characterised by the formation and the after-treatment of the conductors etching for patterning the conductors H01L21/3213

Abstract

A method is provided for selectively etching native oxides or other contaminants to metal nitrides and metal oxides during manufacture of a semiconductor device. The method utilizes a substantially non-aqueous etchant which includes a source of fluorine ions. In a preferred embodiment, the etchant comprises H₂SO₄ and HF. The etchant selectively etches native and doped oxides or other contaminants without excessively etching metal nitrides or metal oxides on the substrate or on adjacent exposed surfaces.

Claims

1. A method for selectively etching silicon oxide on a semiconductor-based substrate surface in the presence of directly underlying or exposed surfaces of metal oxides and metal nitrides without attacking said metal oxides and metal nitrides comprising exposing the silicon oxide to a substantially non-aqueous etchant comprising a source of fluorine ions, said substantially non-aqueous etchant containing less than about 1.0% by weight water and having a H+ ion concentration of greater than 10⁻

4 g moles of H+ ions per liter of etchant.

2. The method of claim 1 wherein said etchant comprises a mixture of an organic solvent and ammonium fluoride.

3. The method of claim 2 wherein said organic solvent comprises isopropyl alcohol.

4. The method of claim 2 wherein said etchant further comprises ammonium hydroxide.

5. The method of claim 1 wherein said etchant comprises dilute hydrogen fluoride, an organic solvent, and ammonium fluoride.

6. The method of claim 5 wherein said organic solvent comprises isopropyl alcohol.

7. The method of claim 1 wherein said etchant comprises sulfuric acid and hydrogen fluoride.

8. The method of claim 1 wherein said etchant comprises acetic acid and hydrogen fluoride.

9. The method of claim 1 wherein said etchant comprises a fluorinated gas plasma.

10. The method of claim 1 wherein said etchant comprises a vapor phase solution comprising hydrogen fluoride.