Fine Grained, Non Banded, Refractory Metal Sputtering Targets with a Uniformly Random Crystallographic Orientation, Method for Making Such Film, and Thin Film Based Devices and Products Made Therefrom

• US 20080271779A1
• Filed: 11/08/2007
• Published: 11/06/2008
• Est. Priority Date: 05/04/2007
• Status: Active Grant

• Current Assignee: Materion Newton Incorporated (Materion Corporation)
• Original Assignee: H.C. Starck Inc. (OPUS Investment SARL)
• Inventors: Kumar, Prabhat, Zimmermann, Stefan, Sun, Shuwei, Miller, Steven A., Wu, Richard, Schmidt-Park, Olaf
• Granted Patent: US 8,197,894 B2
• Time in Patent Office: Days
• US Class Current: 136/252
• CPC Class Codes: B22F 1/052 characterised by a mixture of particles of different sizes or by the particle size distribution
• CPC Class Codes: B22F 2005/103 Cavity made by removal of insert
• CPC Class Codes: B22F 5/106 Tube or ring forms
• CPC Class Codes: C22C 1/045 Alloys based on refractory metals
• CPC Class Codes: C22C 2200/00 Crystalline structure
• CPC Class Codes: C23C 14/0057 using reactive gases other than O2, H2O, N2, NH3 or CH4
• CPC Class Codes: C23C 14/0089 in metallic mode
• CPC Class Codes: C23C 14/0641 Nitrides C23C14/0617 takes precedence
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence
• CPC Class Codes: C23C 14/14 Metallic material, boron or silicon
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: C23C 24/04 Impact or kinetic deposition of particles
• CPC Class Codes: C23C 4/134 Plasma spraying
• CPC Class Codes: H01J 2237/332 Coating
• CPC Class Codes: H01J 37/3426 Material

Abstract

The invention relates to a sputtering target which has a fine uniform equiaxed grain structure of less than 44 microns, no preferred texture orientation as measured by electron back scattered diffraction (“EBSD”) and that displays no grain size banding or texture banding throughout the body of the target. The invention relates a sputtering target with a lenticular or flattened grain structure, no preferred texture orientation as measured by EBSD and that displays no grain size or texture banding throughout the body of the target and where the target has a layered structure incorporating a layer of the sputtering material and at least one additional layer at the backing plate interface, said layer has a coefficient of thermal expansion (“CTE”) value between the CTE of the backing plate and the CTE of the layer of sputtering material. The invention also relates to thin films and their use of using the sputtering target and other applications, such as coatings, solar devices, semiconductor devices etc. The invention further relates to a process to repair or rejuvenate a sputtering target.

Claims

1. A sputtering target which comprises a fine uniform equiaxed grain structure of less than 44 microns, no preferred texture orientation as measured by electron back scattered diffraction (“

EBSD”

) and that displays no grain size banding or texture banding throughout the body of the target.

2. The target of claim 1 in which there is substantially no interparticle diffusion.

3. The target as claimed in claim 1, wherein the average grain size is smaller than 20 microns.

4. The target as claimed in claim 1, wherein the average grain size is smaller than 10 microns.

5. The target as claimed in claim 1, wherein the target has a layered structure incorporating a layer of the desired sputtering material and at least one additional layer at the backing plate interface, said layer having a coefficient of thermal expansion (“

CTE”

) value between the CTE of the backing plate and the CTE of the layer of sputtering material.

18. A method of sputtering which comprises subjecting the sputtering target of claim 1 to sputtering conditions and thereby sputtering the target.

19. The method as claimed in claim 18, wherein the sputtering is done using a sputtering method selected from the group consisting of magnetron sputtering, pulse laser sputtering, ion beam sputtering, triode sputtering, and combinations thereof.

22. A method for making a thin film, comprising the steps of:

(a) making a sputtering target by cold spray or kinetic spray;

(b ) sputtering the sputtering target according to claim 1;

(c) removing metal atoms from the target; and

(d) forming a thin film comprising those metal atoms onto a substrate.

23. The method as claimed in claim 22, wherein after (b), a step further comprising a step of supplying a reactive gas to the metal atoms can be added.

24. The method as claimed in claim 23, wherein the reactive gas is oxygen, nitrogen and/or a silicon containing gas.

25. The method according to claim 24, wherein the thin film has a thickness ranging from 0.5 nm to 10 μ

m.

26. A thin film made in accordance with the method of claim 22.

27. A flat panel display device comprising the thin film according to claim 26.

28. The flat panel device according to claim 27, wherein the device is selected from the group consisting of Thin Film Transistor—

Liquid Crystal Displays, Plasma Display Panels, Organic Light Emitting Diodes, Inorganic Light Emitting Diode Displays, and Field Emission Displays.

33. A thin film made in accordance with the method of claim 29, with a film nonuniformity of less than 4% from a target with the microstructure of claim 1.

34. A flat panel display device comprising the thin film according to claim 33.

35. The flat panel device according to claim 34, wherein the device is selected from the group consisting of Thin Film Transistor Liquid Crystal Displays, Plasma Display Panels, Organic Light Emitting Diodes, Inorganic Light Emitting Diode Displays, and Field Emission Displays.

36. A solar cell device comprising the thin film as claimed in claim 33 as barrier a layer and back contact.

37. A magnetic disk-drive storage device comprising the film according to claim 33.

38. A semiconductor memory device comprising the film according to claim 33.

39. A coated architectural glass which comprises the thin film according to claim 33 in contact with the surface of the architectural glass and wherein the thin film is a zinc oxide thin film.

40. A process of coating architectural glass which comprises coating architectural glass with the thin film as claimed in claim 33.

41. An ink jet printing head which comprises the film as claimed in claim 33.

42. An optical coating with comprises a reflective or antireflective material and the film as claimed in claim 33 wherein said film is in contact with said reflective or antireflective material.

43. A diffusion barrier layer in between a copper layer and a silicon substrate which comprises the film as claimed in claim 33.

44. The target as claimed in claim 1, wherein the target is a plate, tubular or profiled target.

47. A sputtering target and a sputtering target assembly that has been previously sputtered to the end of its useful life and has then been repaired by filling in the eroded volume with a densified powder resulting in the entire volume of the target having the microstructure of claim 1.

6. A sputtering target with a lenticular or flattened grain structure, no preferred texture orientation as measured by electron back scattered diffraction (“

EBSD”

) and that displays no grain size or texture banding throughout the body of the target and where the target has a layered structure incorporating a layer of the sputtering material and at least one additional layer at the backing plate interface, said layer has a coefficient of thermal expansion (“

CTE”

) value between the CTE of the backing plate and the CTE of the layer of sputtering material.

7. The target as claimed in claim 6, in which there is substantially no interparticle diffusion.

20. A method of sputtering which comprises subjecting the sputtering target of claim 6 to sputtering conditions and thereby sputtering the target.

21. The method as claimed in claim 20, wherein the sputtering is done using a sputtering method selected from the group consisting of magnetron sputtering, pulse laser sputtering, ion beam sputtering, triode sputtering, and combinations thereof

29. A method for making a thin film, comprising the steps of:

(a) making a sputtering target by cold spray or kinetic spray;

(b) sputtering the sputtering target according to claim 6;

(c) removing metal atoms from the target; and

(d) forming a thin film comprising those metal atoms onto a substrate.

30. The method as claimed in claim 29, wherein after (b), a step further comprising a step of supplying a reactive gas to the metal atoms can be added.

31. The method as claimed in claim 30, wherein the reactive gas is oxygen, nitrogen and/or a silicon containing gas.

32. The method according to claim 29, wherein the thin film has a thickness ranging from 0.5 nm to 10 μ

m.

45. The target as claimed in claim 6, wherein the target is a plate, tubular or profiled target.

48. A sputtering target and a sputtering target assembly that has been previously sputtered to the end of its useful life and has then been repaired by filling in the eroded volume with a densified powder resulting in the entire volume of the target having the microstructure of claim 6.

8. A process for manufacturing a sputtering target assembly in an additive manner which comprises depositing a target powder material via a powder spray directly upon the backing plate or backing tube so that the target assembly is manufactured in a single step and subsequent machining of backing plate or backing tube to final target assembly dimensions wherein the target comprises a fine uniform equiaxed grain structure of less than 44 microns, that has substantially no interparticle diffusion and no preferred texture orientation as measured by electron back scattered diffraction (“

EBSD”

) and that displays no grain size or texture banding throughout the body of the target.

9. The process as claimed in claim 8, wherein the spray is performed by a cold spray process.

10. The process as claimed in claim 8, wherein the spray is performed by a kinetic spray process.

11. The process as claimed in claim 8, wherein the target has a lenticular or flattened grain structure characterized by no interparticle diffusion that has no preferred texture orientation as measured by electron back scattered diffraction (“

EBSD”

) and that displays no grain size or texture banding throughout the body of the target.

14. The process as claimed in claim 8, wherein the process is a cold spray process which comprises directing on a target a gas flow wherein the gas flow forms a gas-powder mixture with a powder of a material selected from the group consisting of niobium, tantalum, tungsten, molybdenum, titanium, zirconium and mixtures of at least two thereof or their alloys with at least two thereof or with other metals, the powder has a particle size of from 0.5 to 150 μ

m , wherein a supersonic speed is imparted to the gas flow and the jet of supersonic speed is directed onto the surface of target thereby cold spraying a target with a fine, completely random and uniformly random (thru thickness) grain size and crystallographic texture.

15. The process as claimed in claim 14, wherein the spraying is performed with a cold spray gun and the target to be coated and the cold spray gun are located within an environmental control chamber at pressures greater than 0.1 MPa.

12. A target assembly which comprises a target and a backing plate material wherein the coefficients of thermal expansion of the backing plate material and the target are closely matched and the melting point of the backing plate material is at least 200 C above the temperature at which the target material can be annealed.

13. The target assembly of claim 12, wherein the target has been annealed as an assembly to relax any as sprayed stresses.

16. A process for making targets of multiple metal powders which comprises applying a mixture of metal powders to a backing plate to provide compliance between the target and the backing plate so that there is no detectable interdiffusion of the metals that would result in the formation of undesirable phases.

17. The process as claimed in claim 16, wherein the metal powders comprise a mixture of at least two metals selected from the group consisting of tungsten, molybdenum, tantalum, niobium, titanium and zirconium.

46. The process as claimed in claim 16, wherein said applying the mixture of powders is by cold spraying or kinetic spraying.

49. A sputtering target and a sputtering target assembly that has been previously sputtered to the end of its useful life and has then been repaired by filling in the eroded volume with a densified powder resulting in a equiaxed microstructure of the new material being significantly finer in grain size than the original material.

50. A thermal management material made by a process which comprises cold or kinetic spraying a mixture of powders consisting of a refractory powder and a highly thermally conducting metal powder to form a composite structure on substrate.

51. The process as claimed in claim 50, wherein said thermally conducting metal powder is Ag, Au and the substrate is a stainless steel substrate.

52. The process as claimed in claim 51, wherein the stainless steel substrate is removed by machining.