Method of manufacturing a process chamber component having yttrium-aluminum coating

1. A method of manufacturing a substrate processing chamber component, the method comprising:

(a) forming a chamber component comprising a structure comprising a metal alloy composed of yttrium and aluminum; and

(b) anodizing a surface of the metal alloy structure by applying an electrical bias to the structure in an acidic solution to form an anodized coating of yttrium aluminum garnet.

2. A method according to claim 1 comprising forming a structure comprising a metal alloy having an yttrium content of less than about 50% by weight.

3. A method according to claim 1 comprising anodizing the surface of the metal alloy of the structure to form an anodized coating having a thickness of from about 0.5 mils to about 8 mils.

4. A method according to claim 1 comprising anodizing the surface of the metal alloy of the structure in an acidic solution comprising one or more of oxalic acid, chromic acid and sulfuric acid.

5. A method according to claim 1 comprising anodizing the surface of the metal alloy of the structure for from about 30 minutes to about 120 minutes.

6. A method according to claim 1 comprising anodizing the surface of the metal alloy of the structure to form an anodized coating of yttrium aluminum garnet having a compositional gradient through a thickness of the anodized coating.

7. A method according to claim 1 wherein the molar ratio of yttrium to aluminum in the metal alloy is 3:5.

8. A method according to claim 1 comprising forming the structure of the chamber component by at least one of: casting and machining.

9. A method according to claim 1 comprising anodizing the surface of the metal alloy of the structure in an acid solution comprising from about 0.5 M to about 1.5 M of sulfuric acid.

10. A method according to claim 1 comprising, before (b), cleaning the surface of the metal alloy of the structure by at least one of: immersing the metal alloy in acidic solution and ultrasonically cleaning.

11. A method of manufacturing a plasma process chamber component, the method comprising:

(a) forming a structure comprising a metal alloy composed of yttrium and aluminum; and

(b) anodizing a surface of the structure by applying an electrical bias to the structure in an acidic solution while controlling the anodizing process parameters to form on the structure, a coating comprising yttrium aluminum garnet having a compositional gradient through a thickness of the coating.

12. A method according to claim 11 comprising anodizing the surface of the metal alloy of the structure in an acidic solution comprising one or more of oxalic acid, chromic acid and sulfuric acid.

13. A method according to claim 11 comprising anodizing the surface of the metal alloy of the structure in an acidic solution comprising from about 0.5 M to about 1.5 M of sulfuric acid.

14. A method according to claim 11 wherein the molar ratio of yttrium to aluminum in the metal alloy is 3:5.

15. A method according to claim 11 comprising forming the chamber component by at least one of: casting and machining.

16. A method according to claim 11 comprising, before (b), cleaning the surface of the metal alloy of the structure by at least one of: immersing the metal alloy in acidic solution and ultrasonically cleaning.

17. A method of manufacturing a plasma process chamber component, the method comprising:

(a) anodizing a surface of a metal alloy composed of aluminum and yttrium by applying an electrical bias to the structure in an acidic solution to form, on the metal alloy, an anodized coating of yttrium aluminum garnet; and

(b) shaping the anodized metal alloy into a structure capable of use as a plasma process chamber component.

18. A method according to claim 17 comprising anodizing the surface of the metal alloy in an acidic solution comprising one or more of oxalic acid, chromic acid and sulfuric acid.

19. A method according to claim 17 comprising anodizing the metal alloy in an acidic solution comprising from about 0.5 M to about 1.5 M of sulfuric acid.

20. A method according to claim 17 wherein the molar ratio of yttrium to aluminum in the metal alloy is 3:5.

21. A method according to claim 17 comprising forming the chamber component by at least one of: casting and machining.

22. A method according to claim 17 comprising, before (a), cleaning the surface of the metal alloy by at least one of: immersing the metal alloy in acidic solution and ultrasonically cleaning.

23. A method according to claim 17 wherein (b) comprises shaping the anodized metal alloy by welding.