Diffusion bonded assemblies and fabrication methods

• US 20040129559A1
• Filed: 10/15/2003
• Published: 07/08/2004
• Est. Priority Date: 04/12/2002
• Status: Abandoned Application

• Current Assignee: Josh W. Misner
• Original Assignee: Josh W. Misner
• Inventors: Misner, Josh W.
• Application Number:
  US10/475,251
• Publication Number:
  US 20040129559A1
• Time in Patent Office: Days
• US Class Current: 204/298.12
• CPC Class Codes: B23K 20/023 Thermo-compression bonding
• CPC Class Codes: C23C 14/3407 Cathode assembly for sputtering apparatus, e.g. Target

Abstract

A diffusion bonded PVD target assembly (30) includes a target blank (34) bonded directly to a backing plate (32), a majority crystal structure of the target blank comprising a HCP structure. The target blank can include cobalt and the backing plate can include an aluminum or copper alloy. The target assembly can exhibit a thickness dependent high PTF, such as at least about 60%. A PVD target fabrication method includes diffusion bonding a target blank to a backing plate, a majority crystal structure of the target blank comprising a HCP structure; transitioning at least some of the HCP structure to a non-HCP structure; and restoring a majority of the non-HCP structure to the HCP structure. The transitioning can include hot pressing the target blank and backing plate at a temperature exceeding a HCP to non-HCP transition temperature of the target blank. The restoring can include cooling at a specified low rate.

Claims

1. A diffusion bonded PVD target assembly comprising a target blank bonded directly to a backing plate, a majority crystal structure of the target blank comprising a HCP structure and the target blank comprising a magnetic material.

2. The target assembly of claim 1 wherein the target assembly lacks an interlayer between the target blank and the backing plate.

3. The target assembly of claim 1 wherein the target blank consists essentially of cobalt or a cobalt alloy with cobalt as the predominate metal.

4. The target assembly of claim 1 wherein the backing plate consists essentially of aluminum, an aluminum alloy with aluminum as the predominate metal, copper, or a copper alloy with copper as the predominate metal.

5. The target assembly of claim 1 exhibiting a high PTF.

6. The target assembly of claim 1 exhibiting a PTF of at least about 60%.

7. The target assembly of claim 1 wherein the diffusion bond exhibits a bond strength of greater than about 11 ksi (76 MPa).

8. The target assembly of claim 1 wherein the target assembly comprises a sputtering target assembly.

9. A diffusion bonded PVD target assembly comprising a target blank bonded directly to a backing plate, the target blank consisting essentially of cobalt or a cobalt alloy, with cobalt as the predominate metal, and exhibiting a high PTF.

10. The target assembly of claim 9 wherein the target assembly lacks an interlayer between the target blank and the backing plate.

11. The target assembly of claim 9 wherein the target blank consists of cobalt.

12. The target assembly of claim 9 wherein the backing plate consists essentially of aluminum, an aluminum alloy with aluminum as the predominate metal, copper, or a copper alloy with copper as the predominate metal.

13. The target assembly of claim 9 exhibiting a PTF of at least about 60%.

14. The target assembly of claim 9 wherein the target blank comprises a target surface, a majority crystal structure of the target blank comprises a HCP structure, and a majority crystallographic orientation of the target blank comprises a {002} HCP plane that is substantially parallel to the target surface within a test region.

15. The target assembly of claim 14 wherein the target surface comprises a sputtering surface of the target assembly and the {002} HCP plane is substantially parallel to the sputtering surface across the entirety of the sputtering surface.

16. A diffusion bonded PVD target assembly comprising a target blank bonded to a backing plate, the target blank comprising a target surface and a magnetic material, a majority crystal structure of the target blank comprising a HCP structure, and a majority crystallographic orientation of the target blank comprising a {002} HCP plane that is substantially parallel to the target surface within a test region.

17. The target assembly of claim 16 wherein the target blank is bonded directly to a backing plate.

18. The target assembly of claim 16 wherein the test region defines a representative test region.

19. The target assembly of claim 16 wherein the target surface comprises a sputtering surface of the target assembly and the {002} HCP plane is substantially parallel to the sputtering surface across the entirety of the sputtering surface.

20. The target assembly of claim 16 wherein the target blank consists essentially of cobalt or a cobalt alloy with cobalt as the predominate metal.

21. The target assembly of claim 16 exhibiting a high PTF.

22. A PVD target fabrication method comprising:

diffusion bonding a target blank to a backing plate and forming a target assembly, a majority crystal structure of the target blank comprising a HCP structure;

transitioning at least some of the HCP structure to a non-HCP structure; and

restoring a majority of the non-HCP structure to the HCP structure.

23. The method of claim 22 wherein the target blank comprises a magnetic material.

24. The method of claim 22 wherein the target blank consists essentially of cobalt or a cobalt alloy with cobalt as the predominate metal.

25. The method of claim 22 wherein the backing plate consists essentially of aluminum, an aluminum alloy with aluminum as the predominate metal, copper, or a copper alloy with copper as the predominate metal.

26. The method of claim 22 wherein the transitioning comprises hot pressing the target blank and backing plate during the diffusion bonding at a temperature exceeding a HCP to non-HCP transition temperature of the target blank.

27. The method of claim 22 wherein the non-HCP structure comprises a FCC structure.

28. The method of claim 22 wherein the target blank exhibits a high PTF both before the diffusion bonding and after the restoring.

29. The method of claim 28 wherein the restoring comprises cooling the target blank from a diffusion bonding temperature to a room temperature of from about 10°

C. to about 30°

C. at a rate sufficient that the PTF after the restoring changes by greater than −

10% in comparison to the PTF before the diffusion bonding.

30. The method of claim 22 wherein the target assembly lacks an interlayer between the target blank and the backing plate.

31. The method of claim 22 wherein the diffusion bond exhibits a bond strength of greater than about 11 ksi (76 MPa).

32. The method of claim 22 wherein the target assembly comprises a sputtering target assembly.

41. A PVD target assembly produced by the method of claim 22.

33. A PVD target fabrication method comprising:

diffusion bonding a target blank to a backing plate at a bonding temperature and forming a target assembly; and

cooling the target blank from the bonding temperature to a room temperature of from about 10°

C. to about 30°

C. at a rate sufficient that PTF of the diffusion bonded target blank changes by greater than −

10% in comparison to the target blank PTF before the diffusion bonding.

34. The method of claim 33 wherein the cooling rate comprises less than or equal to about 5°

C. per minute.

35. The method of claim 33 wherein the PTF changes by about 0%.

36. The method of claim 33 wherein the target blank consists essentially of cobalt or a cobalt alloy with cobalt as the predominate metal.

37. The method of claim 33 wherein the backing plate consists essentially of aluminum, an aluminum alloy with aluminum as the predominate metal, copper, or a copper alloy with copper as the predominate metal.

38. The method of claim 33 wherein the target blank exhibits a high PTF both before the diffusion bonding and after the cooling.

42. A PVD target assembly produced by the method of claim 33.

39. A PVD target fabrication method comprising:

diffusion bonding a cobalt-comprising target blank to an aluminum-comprising backing plate at a bonding temperature of greater than 412°

C. and forming a target assembly, the target blank exhibiting a PTF of at least about 60% before the diffusion bonding; and

cooling the target blank from the bonding temperature to a room temperature of from about 10°

C. to about 30°

C. at a rate of no more than about 5°

C. per minute, the diffusion bonded target assembly exhibiting a PTF of at least about 60% after the cooling.

40. The method of claim 39 wherein the target blank comprises a target surface, a majority crystal structure of the target blank comprises a HCP structure, and a majority crystallographic orientation of the target blank comprises a {002} HCP plane that is substantially parallel to the target surface within a test region.

43. A PVD target assembly produced by the method of claim 39.