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 partially refurbished sputtering target comprising:
a target plate (i) comprising a target material and (ii) having a surface contour defining (a) a top surface and (b) a recessed region having a surface recessed below the top surface; and
disposed on the target plate adjacent but not within the recessed region, a layer of unmelted metal powder (i) having a top surface (a) approximately coplanar with the top surface of the target plate or (b) recessed below the top surface to a depth no deeper than a depth of the surface of the recessed region, and (ii) having an interface with the plate disposed at a depth deeper than the surface of the recessed region.
2. The partially refurbished sputtering target of claim 1 , wherein the top surface of the layer of unmelted metal powder is approximately coplanar with the top surface of the target plate.
3. The partially refurbished sputtering target of claim 1 , wherein the top surface of the layer of unmelted metal powder is recessed below the top surface to a depth shallower than the depth of the surface of the recessed region.
4. The partially refurbished sputtering target of claim 1 , wherein the top surface of the layer of unmelted metal powder is recessed below the top surface to a depth substantially equal to ±10% the depth of the surface of the recessed region.
5. The partially refurbished sputtering target of claim 1 , further comprising a sputtering tool in which the target plate is disposed.
6. The partially refurbished sputtering target of claim 1 , wherein the layer of unmelted metal powder comprises the target material.
7. The partially refurbished sputtering target of claim 1 , further comprising a backing plate affixed to the target plate.
8. The partially refurbished sputtering target of claim 7 , wherein the backing plate comprises a material having a melting point lower than a melting point of the target material.
9. The partially refurbished sputtering target of claim 7 , wherein the backing plate comprises at least one of copper, aluminum, or steel.
10. The partially refurbished sputtering target of claim 7 , wherein the target plate is affixed to the backing plate with a bonding agent.
11. The partially refurbished sputtering target of claim 10 , wherein a melting point of the bonding agent is less than approximately 200° C.
12. The partially refurbished sputtering target of claim 10 , wherein the bonding agent comprises indium solder.
13. The partially refurbished sputtering target of claim 1 , wherein:
the target plate has a first grain size and a first crystalline microstructure, and
the layer of unmelted metal powder has at least one of (i) a second grain size finer than the first grain size, or (ii) a second crystalline microstructure more random than the first crystalline microstructure.
14. The partially refurbished sputtering target of claim 13 , wherein the target plate was initially formed by ingot metallurgy or powder metallurgy.
15. The partially refurbished sputtering target of claim 13 , further comprising a distinct boundary line between the target plate and the layer of unmelted powder.
16. The partially refurbished sputtering target 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.
17. The partially refurbished sputtering target 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.
18. The partially refurbished sputtering target of claim 1 , wherein a volume of the layer of unmelted metal powder is less than a volume of the recessed region.
19. The partially refurbished sputtering target of claim 1 , wherein:
the target plate is rectangular and has first and second opposing ends;
the recessed region and the layer of unmelted metal powder collectively define an annulus, the surface contour of at least a portion of a center of the annulus corresponding to the top surface of the target plate; and
the layer of unmelted metal powder is disposed within (i) a first end portion of the annulus proximate the first end of the target plate and (ii) a second end portion of the annulus proximate the second end of the target plate.