Lithium sputter targets
Described are methods of fabricating lithium sputter targets, lithium sputter targets, associated handling apparatus, and sputter methods including lithium targets. Various embodiments address adhesion of the lithium metal target to a support structure, avoiding and/or removing passivating coatings formed on the lithium target, uniformity of the lithium target as well as efficient cooling of lithium during sputtering. Target configurations used to compensate for non-uniformities in sputter plasma are described. Modular format lithium tiles and methods of fabrication are described. Rotary lithium sputter targets are also described.
1. A lithium sputter target comprising:
i) a backing support having a planar topography; and
ii) a layer of lithium metal adhered to the planar topography of the backing support; and
iii) an external non-planar lithium target surface of the lithium metal layer,
wherein the external non-planar lithium target surface varies in planarity in its central region, having contours that vary in height between about 1 mm and about 20 mm, and
wherein the central region of the external non-planar lithium target surface is a sputter surface.
2. The lithium sputter target of claim 1 , wherein the backing support is a backing plate or a backing tube.
3. The lithium sputter target of claim 2 , wherein the backing support comprises copper.
4. The lithium sputter target of claim 3 , wherein the backing support comprises an adhesion layer.
5. The lithium sputter target of claim 4 , wherein the adhesion layer comprises at least one of nickel and molybdenum.
6. A lithium sputter target comprising:
i) a backing support having one or more textured features comprising a heat exchanger having a network of coolant conduits outside the outer surface of the backing support; and
ii) lithium cast or sprayed onto the one or more textured features, wherein the lithium covers at least a portion of the network of coolant conduits forming a target surface.
7. The lithium sputter target of claim 6 , wherein the backing support is a backing plate or a backing tube and wherein the one or more textured features further comprises at least one of knurling, and ground or milled features.
8. The lithium sputter target of claim 6 , wherein the backing support is a backing plate or a backing tube, and wherein the one or more textured features further comprises a bolt, a stud, a pin or a rod, each optionally comprising knurling, threads or an uneven surface topography.
9. The lithium sputter target of claim 6 , wherein the network of coolant conduits comprises copper.
10. The lithium sputter target of claim 8 , wherein the bolt, the stud, the pin, or the rod comprises copper.
11. The lithium sputter target of claim 8 , wherein the one or more textured features comprises an adhesion layer.
12. The lithium sputter target of claim 11 , wherein the adhesion layer comprises at least one of nickel and molybdenum.
13. A sputter target backing plate comprising:
i) a unitary body comprising copper; and
ii) a recess in the unitary body;
wherein the recess comprises perimeter sidewalls and an opening between the perimeter sidewalls, and wherein the top of the perimeter sidewalls have a surface area that is between 1% and 10% of the surface area of the opening of the recess.
14. The sputter target backing plate of claim 13 , wherein perimeter sidewalls have an outer surface that is substantially planar and vertical or angled, or curved and convex or concave.
15. A rotary sputter target comprising:
i) a backing tube;
ii) a heat exchanger outside the outer surface of the backing tube, the heat exchanger comprising a network of coolant conduits; and
iii) a target metal with a melting point below 450 degrees Celsius, wherein the target metal is applied to the outer surface of the backing tube such that the target metal covers at least a portion of the network of coolant conduits and the target metal forms a target surface that approximates the shape of the outer surface of the backing tube.
16. The rotary sputter target of claim 15 , wherein the network of cooling conduits extend between about 1 mm and about 20 mm from the surface of the backing tube and wherein the rotary sputter target is between 1000 mm and about 2500 mm long.