Hollow cathode target and methods of making same
View Patent ↗Sputtering targets and methods of making sputtering targets are described. The method includes the steps of: providing a sputtering metal workpiece made of a valve metal; transverse cold-rolling the sputtering metal workpiece to obtain a rolled workpiece; and cold-working the rolled workpiece to obtain a shaped workpiece. The sputtering targets exhibits a substantially consistent grain structure and/or texture on at least the sidewalls.
1. A method of making a hollow cathode magnetron sputtering target comprising the steps of:
providing a sputtering metal workpiece comprising at least one valve metal;
transverse cold-rolling the sputtering metal workpiece to obtain a rolled workpiece; and
cold-working the rolled workpiece to obtain a shaped workpiece that is hollow cylindrical or cup-shaped, wherein said valve metal is tantalum, niobium, or an alloy thereof, and
wherein the step of cold-working the rolled workpiece comprises deep-drawing the rolled workpiece, spin-forming the rolled workpiece, or flow forming the rolled workpiece, or combinations thereof; and
further comprising cutting a disc shaped work piece from said rolled work piece prior to cold-working the rolled work piece.
2. The method of claim 1 , wherein the sputtering metal workpiece is not annealed or stress relieved between the steps of transverse cold-rolling and cold-working.
3. The method according to claim 1 , further comprising a step of machine-cleaning the shaped workpiece to obtain the sputtering target.
4. The method according to claim 1 , wherein the step of transverse cold-rolling comprises the step of cold-rolling the sputtering workpiece as a rolling workpiece as many times in the first direction as in the second direction.
5. The method of claim 1 , wherein the step of cold-working the rolled workpiece comprises first deep drawing the rolled workpiece to form a preform, and then flow forming the preform over a mandrel.
6. The method according to claim 1 , wherein the shaped workpiece exhibits at least 50% cold reduction with respect to the rolled sputtering metal workpiece (SMW).
7. The method according to claim 1 , wherein a sidewall of the shaped workpiece exhibits less than 50% cold reduction with respect to the rolled workpiece.
8. The method according to claim 1 , wherein the step of cold-working the rolled workpiece comprises deep-drawing the rolled workpiece or spin-forming the rolled workpiece, or both.
9. The method according to claim 1 , wherein the sputtering target is cup-shaped or cylindrical and has a height of about 10.5 inches, an inner diameter of about 9.25 inches, an outer diameter of about 9.50 inches and a sidewall thickness of about 0.25 inch.
10. The method of claim 1 , wherein said shaped work piece has an edge, wherein said edge is subjected to cold-rolling in order to form a flange.
11. The method of claim 1 , wherein said cold-working is a multi-directional cold-working.
12. The method according to claim 1 , wherein the step of transverse cold-rolling comprises the step of cold-rolling the sputtering workpiece as a rolling workpiece a number of times in a first direction and a number of times in a second direction perpendicular to the first direction.
13. The method according to claim 12 , wherein the step of transverse cold-rolling comprises the steps of:
cold-rolling the sputtering workpiece a number of times in the first direction, and
thereafter cold-rolling the rolling workpiece a number of times in the second direction.
14. The method according to claim 1 , wherein the rolled workpiece has a predetermined cold-rolling thickness.
15. The method according to claim 14 , wherein the predetermined cold-rolling thickness is from about 0.25 inch to about 2″-gauge.
16. The method according to claim 1 , further including a step of annealing the sputtering metal workpiece before the step of transverse cold-rolling.
17. The method according to claim 16 , wherein the step of annealing before the step of transverse cold-rolling is at a temperature of from about 1050° C. to about 1300° C.
18. The method according to claim 16 , wherein the step of annealing before the step of transverse cold-rolling comprises the step of annealing the sputtering metal workpiece for about two hours.
19. The method according to claim 1 , further comprising a step of stress relieving the shaped workpiece after the step of cold-working.
20. The method according to claim 19 , wherein the step of stress relieving after the step of cold-working occurs at a temperature of from about 600° C. to about 850° C.
21. The method according to claim 1 , further comprising a step of annealing the shaped workpiece after the step of cold-working.
22. The method according to claim 21 , wherein the step of annealing after the step of cold-working occurs at a temperature of from about 900° C. to about 1300° C.
23. A method of recovering valve metal from a spent sputtering target made according to the method of claim 1 comprising a step of hydriding the valve metal to obtain hydrided valve metal.
24. The method according to claim 23 , further comprising the steps of:
separating the hydrided valve metal from non-hydrided metal shell;
milling the hydrided valve metal to obtain valve metal hydrided powder;
degassing the valve metal hydrided powder to obtain degassed valve metal powder, and
processing the degassed valve metal powder to obtain a valve metal ingot.
25. The method according to claim 1 , further including a step of stress relieving the sputtering metal workpiece between the steps of transverse cold-rolling and cold-working.
26. The method according to claim 25 , wherein the step of stress relieving is at a temperature of from about 600° C. to about 850° C.
27. The method according to claim 26 , wherein the step of stress relieving comprises the step of stress relieving the sputtering metal workpiece for about 2 hours.
28. The method according to claim 1 , further including a step of annealing the sputtering metal workpiece between the steps of transverse cold-rolling and cold-working.
29. The method according to claim 28 , wherein the step of annealing is at a temperature of from about 950° C. to about 1300° C.
30. The method according to claim 29 , wherein the step of annealing comprises the step of annealing the sputtering metal workpiece for about 2 hours.
31. The method of claim 1 , wherein said sputtering metal work piece is a first plate, and further comprising bonding a second metal backing plate onto the first plate prior to subjecting the rolled work piece to cold-working.
32. The method of claim 31 , wherein said bonding is explosive bonding, mechanical bonding, roll bonding, or combinations thereof.
33. The method of claim 31 , wherein said second metal backing plate is copper.
34. The method of claim 31 , wherein said second metal backing plate is a metal different from said sputtering metal work piece.
35. A method of making a hollow cathode magnetron sputtering target comprising:
a) providing a sputtering metal workpiece comprising at least one valve metal, wherein the step of providing a sputtering metal workpiece comprises steps of forging flat an ingot comprising at least one valve metal, cutting the forged ingot into slabs, and machine-cleaning the slabs and;
b) transverse cold-rolling the sputtering metal workpiece to obtain a rolled workpiece; and
c) cold-working the rolled workpiece to obtain a shaped workpiece that is hollow cylindrical or cup-shaped, wherein said valve metal is tantalum, niobium, or an alloy thereof, and
wherein the step of cold-working the rolled workpiece comprises deep-drawing the rolled workpiece, spin-forming the rolled workpiece, or flow forming the rolled workpiece, or combinations thereof.