Tantalum sputtering target with improved performance and predictability and method of manufacturing
AssigneeTosoh SMD, Inc.
InventorsWeifang Miao, Eduardo del Rio Perez, Alex Kuhn, Michael McCarthy, John Rizer, Erich Theado
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Abstract
A method for making tantalum sputtering targets with stable through thickness {100}+{111} preferred crystallographic orientation volume fraction is disclosed. Starting from electron beam melted tantalum ingots, the method includes various forging, controlled rolling and recrystallization annealing. The resultant tantalum sputtering targets yield stable deposition rate and film uniformity from burn-in through the end-of-life during sputtering. Also disclosed is a tantalum sputtering target made in accordance with the disclosed method.
Claims11
A method of making a tantalum sputtering target comprising the steps of:
- providing a tantalum ingot, said ingot having a generally cylindrical configuration with a central longitudinal axis;
- sectioning said tantalum ingot by cutting said tantalum ingot transverse to said central longitudinal axis to form at least a billet slice;
- wherein said billet slice is generally cylindrical and shorter than said tantalum ingot, when measured along said central longitudinal axis of said tantalum ingot and a central longitudinal axis of said billet slice;
- thermo-mechanically processing said billet slice to form a tantalum target blank, wherein said thermo-mechanically processing is comprised of upset forging reduction and varying rolling reduction;
- said upset forging reduction results in a thickness reduction between about 15%-35% of said billet slice and said varying rolling reduction results in a thickness reduction of said billet slice varying between about 5%-15% per pass;
- wherein localized shear forces are not imparted into said billet slice by said varying rolling reduction.
Dependencies are inferred from the claim text.