Etch method using supercritical fluids

• US 20040118812A1
• Filed: 08/07/2003
• Published: 06/24/2004
• Est. Priority Date: 08/09/2002
• Status: Abandoned Application

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Watkins, James J., Powell, Ronald, Van Cleemput, Patrick A.
• Application Number:
  US10/637,947
• Publication Number:
  US 20040118812A1
• Time in Patent Office: Days
• US Class Current: 216/83
• CPC Class Codes: C23F 1/16 Acidic compositions C23F1/42 takes precedence
• CPC Class Codes: C23F 1/18 for etching copper or alloys thereof
• CPC Class Codes: C23F 1/44 Compositions for etching metallic material from a metallic material substrate of different composition
• CPC Class Codes: C23G 5/032 containing oxygen-containing compounds
• CPC Class Codes: C23G 5/06 using emulsions

Abstract

Methods are described for removing a material from a substrate by dissolving an etchant into a solvent to form a solution; and exposing the substrate to the solution so that the etchant in the solution removes material from the substrate; wherein during the exposure the solution is maintained in a supercritical or near-supercritical phase. The described methods can include additional steps, such as exposing a precursor of the material to a reagent to form the material, and depositing a second material onto the substrate after removing the material from the substrate.

Claims

1. A method of etching a material from a substrate, the method comprising:

dissolving an etchant into a solvent to form a solution;

exposing the substrate to the solution such that the etchant in the solution removes material from the substrate;

wherein during the exposure the solution is maintained in a supercritical or near-supercritical phase.

2. The method of claim 1, wherein the etchant comprises a diketone etchant.

3. The method of claim 2, wherein the etchant comprises hexafluoropentanedione.

4. The method of claim 2, wherein the etchant comprises a non-fluorinated diketone etchant.

5. The method of claim 4, wherein the etchant comprises tetramethylheptanedione.

6. The method of claim 4, wherein the etchant comprises tetramethyloctanedione.

7. The method of claim 1, wherein the solvent comprises CO₂.

8. The method of claim 1, wherein the material comprises a metal oxide.

9. The method of claim 8, wherein the material comprises copper oxide.

10. The method of claim 1, wherein the substrate comprises silicon, a metal, or a metal nitride.

11. The method of claim 1, wherein the substrate comprises a thin film disposed on a layer of a base material.

12. The method of claim 11, wherein the thin film comprises a metal or a metal nitride

13. The method of claim 11, wherein the base material comprises silicon.

14. The method of claim 1, further comprising depositing a derivative of the etched material onto the substrate.

15. The method of claim 14, wherein the removed material is reduced to provide the derivative.

16. The method of claim 15, wherein the removed material comprises copper oxide and the derivative comprises copper.

17. The method of claim 1, wherein the solution comprises a reducing agent.

18. The method of claim 17, wherein the reducing agent is hydrogen.

19. The method of claim 1, further comprising exposing a precursor of the material to a reagent to form the material on the substrate.

20. The method of claim 19, wherein the material comprises a metal oxide, the precursor comprises a metal, and the reagent comprises an oxidizing agent.

21. The method of claim 20, wherein the solvent is the oxidizing agent.

22. The method of claim 20, wherein the oxidizing agent is oxygen.

23. The method of claim 20, wherein the oxidizing agent comprises a peroxide.

24. The method of claim 20, wherein the oxidation occurs while exposing the substrate to the solution.

27. The method of claim 24, wherein the metal portions are simultaneously oxidized and etched.

25. A method of depositing a metal film on a substrate, the method comprising:

maintaining supercritical carbon dioxide and a chelating agent in contact with the substrate to remove an oxide layer from a metal surface of the substrate, thereby forming a precleaned substrate; and

depositing the metal film on the precleaned substrate without exposing the precleaned substrate to a material which oxidizes the metal surface of the precleaned substrate.

26. A method of patterning a metal layer, the method comprising:

selectively oxidizing portions of the metal layer to form metal oxide portions; and

exposing the metal oxide portions to a solution including an etchant to remove the metal oxide portions from the metal layer thereby patterning the metal layer;

wherein during the exposure the solution is maintained in a supercritical or near-supercritical phase.