Methods of forming molybdenum sputtering targets
In various embodiments, tubular sputtering targets are produced by forming a tubular billet at least by pressing molybdenum powder in a mold and sintering the pressed molybdenum powder, working the tubular billet to form a worked billet, and heat treating the worked billet.
1. A method of making a tubular sputtering target comprising:
forming a tubular billet having an inner diameter ID I and an outer diameter OD I , the formation comprising pressing molybdenum powder in a mold and sintering the pressed molybdenum powder;
working the tubular billet to form a worked billet having an outer diameter OD f smaller than OD I ; and
heat treating the worked billet.
2. The method of claim 1 , wherein the molybdenum powder is pressed at a pressure selected from the range of 32 ksi to 40 ksi.
3. The method of claim 1 , wherein the molybdenum powder is pressed at a pressure of at least 16 ksi.
4. The method of claim 1 , wherein pressed molybdenum powder is sintered at a temperature of at least 1785° C.
5. The method of claim 1 , wherein pressed molybdenum powder is sintered at a temperature selected from the range of 1785° C. to 2200° C.
6. The method of claim 1 , wherein a ratio of O I to OD f is at least 3:1.
7. The method of claim 1 , wherein the worked billet is heat treated at a temperature selected from the range of 815° C. to 1375° C.
8. The method of claim 1 , wherein the molybdenum powder is pressed isostatically.
9. The method of claim 1 , wherein the pressed molybdenum powder is sintered in hydrogen.
10. The method of claim 1 , wherein working the tubular billet comprises extruding the tubular billet.
11. The method of claim 10 , wherein the tubular billet is extruded at a temperature of at least 925° C.
12. The method of claim 10 , wherein the tubular billet is extruded at a temperature selected from the range of 925° C. to 1260° C.
13. The method of claim 1 , wherein working the tubular billet comprises rotary forging the tubular billet.
14. The method of claim 1 , wherein the worked billet is substantially recrystallized after heat treating.
15. The method of claim 1 , wherein the worked billet is substantially free of strain after heat treating.
16. The method of claim 1 , wherein the worked billet has a texture having a 110 orientation parallel to a longitudinal direction and a 111 orientation parallel to a radial direction.
17. The method of claim 1 , wherein the worked billet is heat treated at a temperature selected from the range of 1250° C. to 1375° C.
18. The method of claim 1 , wherein the worked billet is heat treated at a temperature selected from the range of 815° C. to 960° C.