Selective silicon oxide etchant formulation including fluoride salt, chelating agent, and glycol solvent

• US 6,383,410 B1
• Filed: 08/08/2001
• Issued: 05/07/2002
• Est. Priority Date: 12/19/1997
• Status: Expired due to Fees

• Current Assignee: Advanced Technology Materials, Inc. (Entegris Incorporated)
• Original Assignee: Advanced Technology Materials, Inc. (Entegris Incorporated)
• Inventors: Fine, Stephen A., Wojtczak, William A., Nguyen, Long
• Primary Examiner(s): Utech, Benjamin L.
• Assistant Examiner(s): UMEZ ERONINI, LYNETTE T
• Application Number:
  US09/925,874
• Publication Number:
  US 20020043644A1
• Time in Patent Office: 272 Days
• Field of Search: 252/79.1, 252/79.3, 252/79.4, 438/745, 438/756
• US Class Current: 252/79.1
• CPC Class Codes: C09K 13/00 Etching, surface-brightening or pickling compositions for glass C03C15/00, C03C25/66; for mortars, concrete, artificial or natural stone or ceramics C04B41/5338 ; for metallic material C23F, C23G1/00, C25F1/00; for semi-conductors H01L
• CPC Class Codes: C09K 13/06 with organic material
• CPC Class Codes: C09K 13/08 containing a fluorine compound
• CPC Class Codes: H01L 21/31105 Etching inorganic layers
• CPC Class Codes: H01L 21/31111 by chemical means

Abstract

The formulations of the present invention etch doped silicon oxide compounds, such as BPSG and PSG layers, at rates greater than or equal to the etch rate of undoped silicon oxide such as thermal oxide. The formulations have the general composition of a chelating agent, preferably weakly to moderately acidic (0.1-10%; preferably 0.2-2.8%); a fluoride salt, which may be ammonium fluoride or an organic derivative of either ammonium fluoride or a polyammonium fluoride (1.65-7%; preferably 2.25-7%); a glycol solvent (71-98%; preferably 90-98%); and optionally, an amine.

Claims

1. A chemical formulation for etching various types of oxide consisting essentially of:

a chelating agent, wherein said chelating agent is selected from the group consisting of iminodiacetic, malonic, oxalic, succinic, boric and malic acids and 2,4 pentanedione;

a fluoride; and

a glycol solvent.

2. The chemical formulation of claim 1, wherein said chelating agent is weakly to moderately acidic, and consists of approximately 0.1-10% by weight of the formulation;

and wherein said fluoride consists of a compound selected from the group consisting of ammonium fluoride, an organic derivative of ammonium fluoride, and a organic derivative of a polyammonium fluoride; and

wherein said fluoride consists of approximately 1.65-7% by weight of the formulation; and

wherein said glycol solvent consists of approximately 73-98.25% by weight of said formulation.

3. The chemical formulation of claim 1, further comprising:

an amine, wherein said amine consists of approximately 0.1-10% by weight of said formulation.

4. The chemical formulation of claim 1, wherein said fluoride is selected from the group consisting of:

Ammonium fluoride,

Pentamethyldiethylenetriammonium trifluoride,

Tetramethylammonium fluoride, and

Triethanolammonium fluorides.

5. The chemical formulation of claim 2, wherein said fluoride is selected from the group consisting of:

Ammonium fluoride,

Pentamethyldiethylenetriammonium trifluoride,

Tetramethylammonium fluoride, and

Triethanolammonium fluorides.

6. The chemical formulation of claim 2, wherein said amine is selected from the group consisting of:

Dicyclohexylamine,

Pentamethyldiethylenetriamine, and

Triethanolamine.

7. The chemical formulation of claim 6, comprising:

8. The chemical formulation of claim 6, comprising:

9. The chemical formulation of claim 6, comprising:

10. The chemical formulation of claim 6, comprising:

11. The chemical formulation of claim 6, comprising:

12. The chemical formulation of claim 6, comprising:

13. The chemical formulation of claim 10, comprising: