SILICON-SELECTIVE DRY ETCH FOR CARBON-CONTAINING FILMS

• US 20110053380A1
• Filed: 08/31/2009
• Published: 03/03/2011
• Est. Priority Date: 08/31/2009
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Ingle, Nitin, Tang, Jing, Wang, Linlin, Sapre, Kedar, Mallick, Abhijit Basu
• Granted Patent: US 8,211,808 B2
• Time in Patent Office: Days
• US Class Current: 438/715
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/31116 by dry-etching

Abstract

A method of etching silicon-and-carbon-containing material is described and includes a SiConi™ etch in combination with a flow of reactive oxygen. The reactive oxygen may be introduced before the SiConi™ etch reducing the carbon content in the near surface region and allowing the SiConi™ etch to proceed more rapidly. Alternatively, reactive oxygen may be introduced during the SiConi™ etch further improving the effective etch rate.

Claims

1. A method of etching a silicon-and-carbon-containing layer on a surface of a substrate in a substrate processing region of a substrate processing chamber, the method comprising:

flowing a fluorine-containing precursor and a hydrogen-containing precursor into a first remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the first remote plasma region to produce plasma effluents;

etching the silicon-and-carbon containing layer by flowing the plasma effluents and reactive oxygen into the substrate processing region while forming solid by-products on the surface of the substrate; and

sublimating the solid by-products by increasing a temperature of the substrate above a sublimation temperature of the solid by-products.

2. The method of claim 1 wherein the fluorine-containing precursor comprises at least one precursor selected from the group consisting of nitrogen trifluoride, hydrogen fluoride, diatomic fluorine, monatomic fluorine and fluorine-substituted hydrocarbons.

3. The method of claim 1 wherein the hydrogen-containing precursor comprises at least one precursor selected from the group consisting of atomic hydrogen, molecular hydrogen, ammonia, a hydrocarbon and an incompletely halogen-substituted hydrocarbon.

4. The method of claim 1 wherein a temperature of the substrate is increased by at least 20°

C. above the temperature of the substrate during the etching operation in order to sublimate the solid by-products.

5. The method of claim 1 wherein a temperature of the substrate during the etching operation is less than or about 80°

C.

6. The method of claim 1 wherein a temperature of the substrate during the etching operation is less than or about 100°

C.

7. The method of claim 1 wherein the surface of the substrate is patterned.

8. The method of claim 1 wherein the reactive oxygen comprises ozone.

9. The method of claim 1 wherein the reactive oxygen comprises atomic oxygen (O).

10. The method of claim 1 wherein the reactive oxygen comprises ozone generated in an ozone generator fluidly coupled to the substrate processing region.

11. The method of claim 1 wherein the reactive oxygen comprises ozone generated by flowing molecular oxygen (O₂) into a second remote plasma region.

12. The method of claim 1 wherein the reactive oxygen comprises ozone generated by flowing a nitrogen-and-oxygen-containing precursor into a second remote plasma region.

13. The method of claim 1 wherein the reactive oxygen does not flow through the first remote plasma region.

14. The method of claim 1 wherein the operations are repeated to remove additional material from the silicon-and-carbon-containing layer.

15. The method of claim 1 wherein a thickness of about 150 Å

or less is removed from the silicon-and-carbon-containing layer.

16. The method of claim 11 wherein the second remote plasma region is coupled to a microwave power source.

17. A method of etching a silicon-and-carbon-containing layer on an interior surface bordering a substrate processing region within a substrate processing system, the method comprising:

flowing a fluorine-containing precursor and a hydrogen-containing precursor into a remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the remote plasma region to produce plasma effluents;

etching the silicon-and-carbon-containing layer by flowing the plasma effluents and reactive oxygen into the substrate processing region while forming solid by-products on the interior surface; and

sublimating the solid by-products by increasing a temperature of the interior surface above a sublimation temperature of the solid by-products.

18. The method of claim 17 wherein the fluorine-containing precursor comprises at least one precursor selected from the group consisting of nitrogen trifluoride, hydrogen fluoride, diatomic fluorine, monatomic fluorine and fluorine-substituted hydrocarbons.

19. The method of claim 17 wherein the hydrogen-containing precursor comprises at least one precursor selected from the group consisting of atomic hydrogen, molecular hydrogen, ammonia, a hydrocarbon and an incompletely halogen-substituted hydrocarbon.

20. A method of etching a silicon-and-carbon-containing layer on a surface of a substrate in a substrate processing region, the method comprising the sequential steps of:

flowing reactive oxygen into the substrate processing region to reduce a concentration of carbon in a near-surface region of the silicon-and-carbon-containing layer;

etching the silicon-and-carbon-containing layer by flowing a fluorine-containing precursor and a hydrogen-containing precursor into a first remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the first remote plasma region to produce plasma effluents, which are flown into the substrate processing region; and

sublimating solid by-products left on the surface following the etching step by raising a temperature of the substrate above a sublimation temperature of the solid by-products.

21. The method of claim 20 wherein the fluorine-containing precursor comprises at least one precursor selected from the group consisting of nitrogen trifluoride, hydrogen fluoride, diatomic fluorine, monatomic fluorine and fluorine-substituted hydrocarbons.

22. The method of claim 20 wherein the hydrogen-containing precursor comprises at least one precursor selected from the group consisting of atomic hydrogen, molecular hydrogen, ammonia, a hydrocarbon and an incompletely halogen-substituted hydrocarbon.

23. The method of claim 20 wherein the reactive oxygen comprises ozone generated by flowing molecular oxygen (O₂) into a second remote plasma region.

24. The method of claim 23 wherein the first remote plasma region is the second remote plasma region.

25. The method of claim 20 wherein a thickness of about 150 Å

or less is removed from the silicon-and-carbon-containing layer.

26. The method of claim 20 wherein the reactive oxygen comprises ozone generated in an ozone generator fluidly coupled to the substrate processing region.

27. The method of claim 20 wherein the steps are repeated to remove additional material from the silicon-and-carbon-containing layer.

28. The method of claim 27 wherein each repetition removes a thickness of about 150 Å

, or less from the silicon-and-carbon-containing layer.

29. The method of claim 20 wherein the reactive oxygen comprises ozone created by flowing oxygen (O₂) into the remote plasma region.

30. The method of claim 20 wherein the reactive oxygen comprises ozone created by flowing a nitrogen-and-oxygen-containing precursor into the remote plasma region.