Sputtering target and manufacturing method thereof
View Patent ↗A sputtering target manufactured by die forging is provided. It is characterized in that an average crystal grain size D at a portion where an average crystal grain size is the largest and an average crystal grain size d at a portion where an average crystal grain size is the smallest are related as 1.0<D/d<2.0. Further provided is a method capable of constantly manufacturing a sputtering target excellent in characteristics by improving and elaborating forging and heat treatment processes to render a crystal size fine and uniform, and a sputtering target excellent in quality obtained by this method.
1. A method of manufacturing a sputtering target, comprising the steps of:
performing hot or cold kneading and straightening annealing to an ingot or billet material;
adjusting crystal grains of the material by performing cold preforming and recrystallization annealing;
thereafter performing die forging; and
after said die forging step, performing straightening or recrystallization annealing.
2. A method according to claim 1 , wherein the sputtering target produced by the method is a hexagonal sputtering target having an erosion face with a total intensity ratio of a (002) face, and a (103) face, (014) face and (015) face within a 30° angle thereof of 30% or more, and variation is within ±10% of an average value.
3. A method according to claim 2 , wherein the sputtering target is made of titanium.
4. A method according to claim 1 , wherein a total absolute value of true strain in said hot or cold kneading is 4 or more.
5. A method according to claim 4 , wherein the material has a melting point of Tm, and said die forging step is performed at a temperature of 0.5Tm or less.
6. A method according to claim 5 , wherein said recrystallization annealing step performed after said cold preforming step and said straightening or recrystallization annealing step performed after said die forging step are performed at a temperature of 0.6Tm or less.
7. A method according to claim 6 , wherein said cold preforming step is performed at a processing ratio of 20 to 90%.
8. A method according to claim 1 , wherein said material has a melting point of Tm and said die forging step is performed at a temperature of 0.5Tm or less.
9. A method according to claim 1 , wherein said material has a melting point of Tm and said recrystallization annealing step performed after said cold preforming is performed at a temperature of 0.6Tm or less.
10. A method according to claim 1 , wherein said material has a melting point of Tm and said straightening or recrystallization annealing step performed after said die forging step is performed at a temperature of 0.6Tm or less.
11. A method according to claim 1 , wherein said cold preforming step is performed at a processing ratio of 20 to 90%.
12. A method according to claim 1 , wherein, as a result of performing recrystallization annealing after cold preforming, an average crystal grain size D 0 at a portion of said target where an average crystal grain size is largest and an average grain size d 0 at a portion of said target where an average crystal grain size is smallest are related as 1.0<D 0 /d 0 <1.5.
13. A method according to claim 1 , wherein, as a result of performing recrystallization annealing after cold preforming, a grain size of said material is 200% or less of an ultimate average crystal grain size of said target.
14. A method according to claim 1 , wherein, as a result of performing straightening or recrystallization annealing after die forging, an average crystal grain size of said target is in a range of 1 to 500 μm.
15. A method according to claim 1 , wherein an average crystal grain size D at a portion of said target where an average crystal grain size is largest and an average grain size d at a portion where an average crystal grain size is smallest are related as 1.0<D/d<2.0.
16. A method according to claim 1 , wherein said target is made of a material selected from a group consisting of copper, titanium, aluminum, nickel, cobalt, tantalum, and alloys thereof.