Methods of rejuvenating sputtering targets
View Patent ↗In various embodiments, a sputtering target initially formed by ingot metallurgy or powder metallurgy and comprising a sputtering-target material is provided, the sputtering-target material (i) comprising a refractory metal, (ii) defining a recessed furrow therein, and (iii) having a first grain size and a first crystalline microstructure. A powder is spray-deposited within the furrow to form a layer therein, the layer (i) comprising the metal, (ii) having a second grain size finer than the first grain size, and (iii) having a second crystalline microstructure more random than the first crystalline microstructure. Spray-depositing the powder within the furrow forms a distinct boundary line between the layer and the sputtering-target material.
1. A method of rejuvenating a sputtering target, the method comprising:
providing a sputtering target initially formed by ingot metallurgy or powder metallurgy and comprising a sputtering-target material, the sputtering-target material (i) comprising a refractory metal, (ii) defining a recessed furrow therein, and (iii) having a first grain size and a first crystalline microstructure; and
spray-depositing a powder within the furrow to form a layer therein, the layer (i) comprising the metal, (ii) having a second grain size finer than the first grain size, and (iii) having a second crystalline microstructure more random than the first crystalline microstructure,
wherein spray-depositing the powder within the furrow forms a distinct boundary line between the layer and the sputtering-target material.
2. The method of claim 1 , wherein the sputtering target comprises a backing plate upon which the sputtering-target material is disposed.
3. The method of claim 2 , wherein the powder is spray deposited without removal of the backing plate from the sputtering-target material.
4. The method of claim 1 , wherein spray-depositing the powder comprises cold spray.
5. The method of claim 1 , wherein the refractory metal is selected from the group consisting of niobium, tantalum, tungsten, molybdenum, zirconium, titanium, and alloys thereof.
6. The method of claim 1 , wherein the layer has a uniformly random texture.
7. The method of claim 1 , wherein the second grain size is less than 44 microns.
8. The method of claim 1 , wherein the second grain size is less than 10 microns.
9. The method of claim 1 , wherein the layer is substantially free of grain-size banding and texture banding.
10. The method of claim 1 , further comprising, after spray-depositing the powder, annealing the sputtering target.
11. The method of claim 1 , further comprising, after spray-depositing the powder, at least one of grinding or polishing a surface of the layer.
12. The method of claim 1 , wherein spray-depositing the powder comprises spray-depositing the powder only in the furrow.
13. The method of claim 1 , wherein spray-depositing the powder comprises spray-depositing the powder in the furrow and on the sputtering-target material outside of the furrow.
14. The method of claim 1 , wherein the sputtering-target material comprises regions of different preferred crystalline orientations, and the layer substantially lacks a preferred crystalline orientation.
15. The method of claim 1 , further comprising, after spray-depositing the powder, diffusion bonding the layer to the sputtering-target material.