Method of selectively removing conductive material
An electrolyte solution, methods, and systems for selectively removing a conductive metal from a substrate are provided. The electrolyte solution comprising nanoparticles that are more noble than the conductive metal being removed, is applied to a substrate to remove the conductive metal selectively relative to a dielectric material without application of an external potential or contact of a processing pad with the surface of the substrate. The solutions and methods can be applied, for example, to remove a conductive metal layer (e.g., barrier metal) selectively relative to dielectric material and to a materially different conductive metal (e.g., copper interconnect) without application of an external potential or contact of a processing pad with the surface of the substrate.
1. A method for removing a conductive metal selectively relative to dielectric material on a substrate, comprising: contacting the substrate with an electrolyte solution absent an abrasive component and without application of an external potential, for a time effective to remove the conductive metal from the substrate selectively relative to the dielectric material by galvanic chemical reaction between the conductive metal and nanoparticles, the electrolyte solution comprising the nanoparticles in a chemically-compatible alcohol solvent and at least one of hydrofluoric acid (HF) in an HF to alcohol ratio of about 5:1 to about 50:1, a salt or an ionic liquid, the nanoparticles comprising a material more noble than said conductive metal.
2. The method of claim 1 , wherein the conductive material is a metal and selectively removed at a metal:dielectric selectivity of about 2:1 or greater without application of an external potential.
3. The method of claim 1 , wherein said material of the nanoparticles is selected from the group consisting of colloidal carbon, glassy carbon, silver, platinum, gold, nickel-chromium, conductive oxides, and engineered colloids or catalysts.
4. The method of claim 1 , wherein said conductive metal is selected from the group consisting of tungsten, chromium and aluminum.
5. The method of claim 1 , wherein the electrolyte solution comprises an ionic liquid.
6. The method of claim 1 , wherein the conductive metal is a barrier metal.
7. The method of claim 6 , wherein the barrier metal is selected from the group consisting of tantalum, tantalum nitride, tantalum silicon nitride, titanium, titanium nitride, titanium silicon nitride, tungsten, tungsten nitride, tungsten silicon nitride, ruthenium, and ruthenium oxide.
8. The method of claim 1 , wherein contacting the substrate with the electrolyte solution comprises dispensing the electrolyte solution onto the substrate.
9. The method of claim 1 , wherein contacting the substrate with the electrolyte solution comprises forming a layer of the electrolyte solution on a processing pad and immersing the substrate in the electrolyte solution.
10. The method of claim 9 , wherein the substrate is immersed in the electrolyte solution but not in contact with the processing pad.
11. The method of claim 9 , wherein the processing pad is soft or compressible.
12. The method of claim 9 , further comprising applying a downward force onto the substrate while immersing to cause a pressure of the electrolyte solution against the substrate.
13. The method of claim 9 , wherein the processing pad comprises channels extending therethrough and the electrolyte solution is flowed through said channels to contact the substrate.
14. The method of claim 1 , wherein the electrolyte solution comprises hydrofluoric acid.
15. The method of claim 14 , wherein the electrolyte solution comprises the hydrofluoric acid and alcohol at a ratio of about 5:1 to about 50:1.
16. The method of claim 1 , wherein the electrolyte solution comprises a salt.
17. The method of claim 16 , wherein the salt is selected from the group consisting of salts of chloride, fluoride, succinate and citrate.
18. The method of claim 17 , wherein the salt is selected from the group consisting of ammonium salts and potassium salts.
19. The method of claim 16 , wherein the electrolyte solution comprises the salt at saturation.
20. The method of claim 16 , comprising at least about 1 wt-% of the salt, based on the total weight of the solution.
21. A method for removing a first conductive metal from a substrate, comprising: contacting the substrate with an electrolyte solution absent an abrasive component and without application of an external potential, for a time effective to remove the first conductive metal from the substrate selectively relative to dielectric material and a second conductive metal on the substrate by galvanic chemical reaction between the first conductive metal and nanoparticles, the electrolyte solution comprising the nanoparticles in a chemically-compatible alcohol solvent and at least one of hydrofluoric acid (HF) in an HF to alcohol ratio of about 5:1 to about 50:1, a salt or an ionic liquid, the nanoparticles comprising a material more noble than said first conductive metal.
22. The method of claim 21 , wherein the first conductive metal is a barrier metal, and the second conductive metal is a non-barrier metal.
23. The method of claim 21 , wherein the second conductive metal is selected from the group consisting of copper, platinum, molybdenum, cobalt, magnesium, nickel, silver, and palladium, aluminum, and alloys thereof.
24. The method of claim 21 , wherein the first conductive metal is selectively removed relative to the second conductive metal at a selectivity of about 10:1 to about 100:1, without an applied potential.
25. A method for removing a conductive metal selectively relative to dielectric material on a substrate, comprising:
continuously moving an electrolyte solution absent an abrasive component over the conductive metal for a time effective to remove the conductive metal from the substrate selectively relative to the dielectric material by galvanic chemical reaction between the conductive metal and nanoparticles within the electrolyte solution without application of an external potential;
the electrolyte solution comprising said nanoparticles in a chemically-compatible alcohol solvent and at least one of hydrofluoric acid (HF) in an HF to alcohol ratio of about 5:1 to about 50:1, a salt or an ionic liquid, the nanoparticles comprising a material more noble than said conductive metal.
26. The method of claim 25 , wherein continuously moving the electrolyte solution over the conductive metal comprises applying an oscillating force or vibrations to agitate the electrolyte solution.
27. The method of claim 25 , wherein continuously moving the electrolyte solution over the conductive metal comprises rotating, vertically moving or horizontally moving the substrate in the electrolyte solution.
28. A method for removing a conductive metal selectively relative to dielectric material on a substrate, comprising:
continuously moving an electrolyte solution absent an abrasive component over the conductive metal, while applying a pressure onto the electrolyte solution, for a time effective to remove the conductive metal from the substrate selectively relative to the dielectric material by galvanic chemical reaction between the conductive metal and nanoparticles within the electrolyte solution without application of an external potential;
the electrolyte solution comprising said nanoparticles in a chemically-compatible alcohol solvent and at least one of hydrofluoric acid (HF) in an HF to alcohol ratio of about 5:1 to about 50:1, a salt or an ionic liquid, the nanoparticles comprising a material more noble than said conductive metal.
29. The method of claim 28 , wherein the pressure is provided by a processing pad situated proximal to the substrate with the electrolyte solution therebetween.
30. The method of claim 28 , wherein the pressure is up to about 5 psi.
31. The method of claim 28 , wherein the pressure is provided by action of a solution dispensing device onto the substrate.
32. A method for electrochemically removing a metal from a substrate surface with an electrolyte solution, comprising:
positioning the substrate comprising said metal to interface with the electrolyte solution, said solution comprising nanoparticles in a chemically-compatible alcohol solvent and at least one of hydrofluoric acid (HF) in an HF to alcohol ratio of about 5:1 to about 50:1, a salt or an ionic liquid, the nanoparticles being more noble than said metal; and
flowing the electrolyte solution over the substrate surface to remove the metal selectively relative to dielectric material by galvanic chemical reaction between the conductive metal and nanoparticles within the electrolyte solution without application of an external potential and absent an abrasive component.
33. A method for electrochemically removing a metal from a substrate surface with an electrolyte solution, comprising:
positioning the substrate surface comprising said metal to interface with the electrolyte solution, said solution comprising nanoparticles in a chemically compatible ionic liquid absent an abrasive component, the nanoparticles being more noble than said metal; and
flowing the electrolyte solution over the substrate surface to remove the metal by galvanic chemical reaction between the metal and the nanoparticles within the electrolyte solution without application of an external potential.
34. A method of removing a conductive metal selectively relative to dielectric material on a substrate, comprising:
positioning the substrate proximal to but not in contact with a processing pad;
applying an electrolyte solution absent an abrasive component over the conductive metal between the substrate and the processing pad without application of an external potential, the electrolyte solution comprising nanoparticles in a chemically compatible alcohol solvent and at least one of hydrofluoric acid (HF) in an HF to alcohol ratio of about 5:1 to about 50:1, a salt or an ionic liquid, the nanoparticles being more noble than said conductive metal; and
causing movement of the electrolyte solution between the substrate and the processing pad for a time effective to selectively remove the conductive metal relative to the dielectric material by galvanic chemical reaction between the metal and the nanoparticles within the electrolyte solution.
35. A method of removing a conductive metal selectively relative to dielectric material on a substrate, comprising:
spraying an electrolyte solution onto the substrate to remove the conductive metal from the substrate selectively relative to the dielectric material by galvanic chemical reaction between the metal and nanoparticles within the electrolyte solution without application of an external potential and absent an abrasive component, the electrolyte solution comprising said nanoparticles in a chemically compatible alcohol solvent and at least one of hydrofluoric acid (HF) in an HF to alcohol ratio of about 5:1 to about 50:1, a salt or an ionic liquid, the nanoparticles being more noble than the conductive metal.
36. A method of removing a conductive metal selectively relative to dielectric material on a substrate, comprising:
immersing the substrate into an electrolyte solution for a time effective to remove the conductive metal selectively relative to the dielectric material by galvanic chemical reaction between the metal and nanoparticles within the electrolyte solution without application of an external potential and absent an abrasive component;
the electrolyte solution comprising said nanoparticles in a chemically-compatible alcohol solvent and at least one of hydrofluoric acid (HF) in an HF to alcohol ratio of about 5:1 to about 50:1, a salt or an ionic liquid, the nanoparticles being more noble than the conductive metal.
37. A method for removing a conductive metal selectively relative to dielectric material on a substrate, comprising:
contacting the substrate with an electrolyte solution absent an abrasive component and without application of an external potential or force for a time effective to remove the conductive metal from the substrate selectively relative to the dielectric material by galvanic chemical reaction between the metal and nanoparticles within the electrolyte solution, the electrolyte solution comprising said nanoparticles in a chemically-compatible alcohol solvent and at least one of hydrofluoric acid (HF) in an HF to alcohol ratio of about 5:1 to about 50:1, a salt or an ionic liquid, the nanoparticles comprising a material more noble than said conductive metal.