Titanium target for sputtering and manufacturing method thereof
A high-purity titanium target for sputtering having a purity of 5N5 (99.9995%) or higher, wherein the high-purity titanium target has no macro pattern on the target surface. An object of this invention is to provide a high-quality titanium target for sputtering, in which impurities causing particles and abnormal discharge phenomena are reduced, and which is free from fractures and cracks even during high-rate sputtering, and capable of stabilizing the sputtering characteristics, effectively inhibiting the generation of particles during deposition, and improving the uniformity of deposition.
1. A high-purity titanium target for sputtering having a purity of 5N5 (99.9995%) or higher, wherein the high-purity titanium target has no macro pattern in which a difference in average crystal grain size is 20% or more and a difference in crystal orientation ratio is 10% or more on the target surface.
2. The high-purity titanium target for sputtering according to claim 1 , wherein an average crystal grain size is 10 μm or less.
3. A method of producing a high-purity titanium target for sputtering having a purity of 5N5 (99.9995%) or higher, wherein a melted and cast ingot is subject to primary forging at a temperature of 800 to 950° C., and subject to secondary forging at a temperature exceeding 500° C. but 600° C. or lower to produce the target having no macro pattern on its surface.
4. The method of producing a high-purity titanium target for sputtering according to claim 3 , wherein cold rolling is performed after the secondary forging, heat treatment is additionally performed at 400 to 460° C., and the ingot is thereafter processed into a target.
5. The method of producing a high-purity titanium target for sputtering according to claim 4 , of which average crystal grain size is 10 μm or less.
6. The method of producing a high-purity titanium target for sputtering according to claim 3 , wherein an average crystal grain size of the target is 10 μm or less.
7. The method of producing a high-purity titanium target for sputtering according to claim 6 , wherein an average crystal grain size at a center part of the target surface, an average crystal grain size of a peripheral part of the target surface, and an average crystal grain size of a part halfway between the center part and the peripheral part of the target surface differ by no more than 20%.
8. The high-purity titanium target for sputtering according to claim 2 , wherein an average crystal grain size at a center part of the target surface, an average crystal grain size of a peripheral part of the target surface, and an average crystal grain size of a part halfway between the center part and the peripheral part of the target surface differ by no more than 20%.
9. The method of producing a high-purity titanium target for sputtering according to claim 6 , wherein the high-purity titanium target has no macro pattern on the target surface such that no part of the target surface has a difference in average crystal grain size of 20% or more and a difference in crystal orientation ratio of 10% or more relative to other parts of the target surface.
10. A method of producing a high-purity titanium target for sputtering, comprising the steps of:
melting and casting titanium having a purity of 5N5 (99.9995%) or higher to produce an ingot;
forging the ingot during a primary forging step at a temperature of 800 to 950° C.;
after said primary forging step, forging the ingot during a secondary forging step at a temperature exceeding 500° C. but 600° C. or lower;
after said secondary forging step, cold rolling the ingot;
after said cold rolling, subjecting the ingot to heat treatment at a temperature of 400 to 460° C.; and
after said heat treatment, processing the ingot into a titanium sputtering target such that the titanium sputtering target has a purity of 5N5 (99.9995h%) or higher, an average crystal grain size of 10 μm or less, and no macro pattern on a surface thereof in which a difference in average crystal grain size is 20% or more and a difference in crystal orientation ratio is 10% or more on the surface.