Method to selectively polish silicon carbide films

Patent metadata

Field	Value
Publication number	US-9548211-B2
Application number	US-63028809-A
Country	US
Kind code	B2
Filing date	Dec 3, 2009
Priority date	Dec 4, 2008
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

Abstract

The present invention provides a method for selectively removing silicon carbide from the surface of a substrate in preference to silicon dioxide. The method comprises abrading a surface of substrate with a polishing composition that comprises a particulate abrasive, at least one acidic buffering agent, and an aqueous carrier.

First claim

What is claimed is:

1. A chemical-mechanical polishing (CMP) method for selectively removing silicon carbide from the surface of substrate in preference to silicon dioxide, the method comprising the steps of:
(a) contacting a surface of the substrate with a polishing pad and an aqueous CMP composition; and
(b) causing relative motion between the substrate and the polishing pad while maintaining a portion of the aqueous CMP composition in contact with the surface between the pad and the substrate for a period of time sufficient to abrade at least a portion of the silicon carbide present in the substrate from the surface;
wherein the aqueous CMP composition contains a particulate alumina-doped colloidal silica abrasive present at a concentration in the range of about 0.1 to about 5 percent by weight, wherein the particulate alumina-doped colloidal silica abrasive is about 600 to about 800 ppm of aluminum based on the particulate weight, and an acidic buffering agent providing a pH in the range of about 2 to about 7, the aqueous CMP composition being capable of abrading silicon carbide present on the surface of the substrate at a higher removal rate than the concurrent abrading of silicon dioxide present on the surface of the substrate.

2. The method of claim 1 wherein the acidic buffering agent comprises an organic acid.

3. The method of claim 2 wherein the organic acid comprises a carboxylic acid, a phosphonic acid, or a combination thereof.

4. The method of claim 2 wherein the organic acid comprises acetic acid.

5. The method of claim 2 wherein the organic acid comprises 1-hydroxyethylidene-1,1-diphosphonic acid.

6. The method of claim 2 wherein the organic acid comprises an amino acid.

7. The method of claim 1 wherein the aqueous CMP composition comprises less than about 0.5 percent by weight of organic materials.

8. The method of claim 1 wherein the acidic buffering agent comprises an inorganic acid.

9. The method of claim 1 wherein the acidic buffering agent comprises a phosphoric acid.

10. The method of claim 1 wherein the particulate alumina-doped colloidal silica abrasive is present at a concentration in the range of about 0.1 to about 2 percent by weight.

11. The method of claim 1 wherein the particulate alumina-doped colloidal silica abrasive comprises alumina-doped colloidal silica having a mean particle size in the range of about 40 to about 150 nm.

12. The method of claim 1 wherein the particulate alumina-doped colloidal silica abrasive has a mean particle size in the range of about 20 nanometers to about 150 nanometers.

13. The method of claim 1 wherein the particulate alumina-doped colloidal silica abrasive has a mean particle size in the range of about 40 nanometers to about 50 nanometers.

14. The method of claim 1 wherein the particulate alumina-doped colloidal silica abrasive has a mean particle size in the range of about 40 nanometers to about 150 nanometers.

15. The method of claim 1 wherein the acidic buffering agent provides a pH in the range of about 2 to about 5.

16. The method of claim 1 wherein the pH of the aqueous CMP composition is in the range of about 3.5 to about 7.

17. A chemical-mechanical polishing (CMP) method for selectively removing silicon carbide from the surface of a substrate in preference to silicon dioxide, the method comprising the steps of:
(a) contacting a surface of the substrate with a polishing pad and an aqueous CMP composition; and
(b) causing relative motion between the substrate and the polishing pad while maintaining a portion of the aqueous CMP composition in contact with the surface between the pad and the substrate for a period of time sufficient to abrade at least a portion of the silicon carbide present in the substrate from the surface;
wherein the aqueous CMP composition contains about 0.1 to about 1 percent by weight of particulate alumina-doped colloidal silica having a mean particle size in the range of about 40 to about 150 nanometers, and wherein the particulate alumina-doped colloidal silica abrasive is about 600 to about 800 ppm of aluminum based on the particulate weight, and a buffering agent comprising an organic acid, the buffering agent providing a pH in the range of about 2 to about 5; the aqueous CMP composition being capable of abrading silicon carbide present on the surface of the substrate at a higher removal rate than the concurrent abrading of silicon dioxide present on the surface of the substrate.

18. The method of claim 17 wherein the organic acid comprises a carboxylic acid, a phosphonic acid, or a combination thereof.

19. The method of claim 17 wherein the organic acid comprises a carboxylic acid.

20. The method of claim 19 wherein the carboxylic acid comprises an amino acid.

21. The method of claim 20 wherein the amino acid comprises glycine.

22. The method of claim 17 wherein the organic acid comprises a phosphonic acid.

23. The method of claim 17 wherein the aqueous CMP composition comprises less than about 0.5 percent by weight of organic materials.

24. The method of claim 17 wherein the pH of the aqueous CMP composition is in the range of about 3.5 to about 7.

Assignees

• Ward William
• Johns Timothy
• Cabot Microelectronics Corp

Inventors

• Ward William
• Johns Timothy

Classifications

• H10P52/403

  of conductive or resistive materials · CPC title

• H10P95/062 Primary

  involving a dielectric removal step · CPC title

• C09G1/02

  containing abrasives or grinding agents {(abrasives as such C09K3/14; polishing of semi-conductors H10P52/40)} · CPC title

• H10P52/00 Primary

  Grinding, lapping or polishing of wafers, substrates or parts of devices · CPC title

• H01L21/31053 Primary

  Electricity · mapped topic