Partial spray refurbishment of sputtering targets
In various embodiments, eroded sputtering targets are partially refurbished by spray-depositing particles of target material to at least partially fill certain regions (e.g., regions of deepest erosion) without spray-deposition within other eroded regions (e.g., regions of less erosion). The partially refurbished sputtering targets may be sputtered after the partial refurbishment without substantive changes in sputtering properties (e.g., sputtering rate) and/or properties of the sputtered films.
1. A method of partially refurbishing an eroded sputtering target having a surface contour defining (i) an upper surface level, (ii) a first eroded region having a surface depth recessed below the upper surface level, and (iii) a second eroded region having a surface depth deeper than the surface depth of the first eroded region, the eroded sputtering target comprising a target material, the method comprising:
spray-depositing particles of the target material to at least partially fill the second eroded region without filling the first eroded region, the surface depth of the first eroded region remaining recessed below the upper surface level thereafter.
2. The method of claim 1 , further comprising sputtering the sputtering target after spray deposition without deposition of target material in the first eroded region therebetween.
3. The method of claim 2 , wherein no surface grinding or polishing is performed on the sputtering target between the spray deposition and the sputtering.
4. The method of claim 1 , wherein spray-depositing particles of the target material comprises cold spraying.
5. The method of claim 1 , wherein the target material comprises at least one of Mo, Ti, Mo/Ti, Nb, Ta, W, Zr, a mixture of two or more thereof or one or more thereof with one or more other metals, or an alloy of two or more thereof or one or more thereof with one or more other metals.
6. The method of claim 1 , wherein the target material comprises at least one of Al, Cu, Ag, Au, Ni, a mixture of two or more thereof or one or more thereof with one or more other metals, or an alloy of two or more thereof or one or more thereof with one or more other metals.
7. The method of claim 1 , wherein, before spray deposition, a volume of the second eroded region is less than a volume of the first eroded region.
8. The method of claim 1 , further comprising annealing at least the spray-deposited particles that are at least partially filling the second eroded region.
9. The method of claim 1 , wherein:
the eroded sputtering target comprises a target plate of the target material and, affixed to the target plate, a backing plate comprising a backing-plate material different from the target material, and
the particles of the target material are spray deposited on the target plate while the target plate is affixed to the backing plate.
10. The method of claim 9 , wherein the target plate is affixed to the backing plate with a bonding agent.
11. The method of claim 10 , wherein a melting point of the bonding agent is less than approximately 200° C.
12. The method of claim 10 , wherein the bonding agent comprises indium.
13. The method of claim 9 , wherein the backing-plate material comprises at least one of copper, aluminum, or steel.
14. The method of claim 1 , wherein the particles of the target material are spray deposited with a spraying apparatus comprising a hand-held spray gun.
15. The method of claim 1 , wherein:
the eroded sputtering target comprises a rectangular target plate of the target material having first and second opposing ends;
the first eroded region defines an annulus, the surface contour of at least a portion of a center of the annulus corresponding to the upper surface level; and
the second eroded region comprises (i) a first end portion of the annulus defined by the first eroded region proximate the first end of the target plate and (ii) a second end portion of the annulus defined by the first eroded region proximate the second end of the target plate.
16. The method of claim 1 , wherein the particles of the target material are spray-deposited via a jet of sprayed particles, an obliquity angle between the jet and the surface contour within the second eroded region being between approximately 45° and approximately 90°.
17. The method of claim 16 , wherein the obliquity angle is between approximately 60° and approximately 90°.
18. The method of claim 1 , wherein the second eroded region is filled with the particles of the target material at least to the surface depth of the first eroded region.
19. The method of claim 1 , wherein the second eroded region is filled with the particles of the target material at least to the upper surface level.
20. The method of claim 1 , wherein particles of the target material are spray-deposited in the first eroded region when particles of the target material are spray-deposited to at least partially fill the second eroded region.
21. The method of claim 1 , wherein substantially no particles of the target material are spray-deposited in the first eroded region when particles of the target material are spray-deposited to at least partially fill the second eroded region.