Tantalum target is a typical metal target, which is widely used in PVD due to its excellent corrosion resistance, electromagnetic shielding performance and energy materials. For example, tantalum can be used as a decorative and protective coating on other metal surfaces and can be produced by vacuum sputtering on tantalum targets. The internal structure, grain size and crystal orientation of tantalum target are the key factors to determine whether the final tantalum target assembly can meet the requirements of semiconductor sputtering.
Tantalum target is obtained by processing tantalum ingot. At present, the purity of tantalum ingot is required to be above 4N(Ta content is not less than 99.99%) when it is used to manufacture tantalum target. Among the existing technologies, the plastic deformation of high purity tantalum ingot to produce high purity tantalum target for semiconductor is less and imperfect, mainly the tantalum target made by conventional forging and emulsification production process. The grain orientation of the tantalum target manufactured by this method is mainly (111), and the grain orientation is not uniform on the cross section. When the tantalum target is applied to the sputtering target, the resistivity of the tantalum film on the silicon wafer is high and the tantalum film is not uniform after sputtering.
Put the first tantalum target blank into the heating furnace, set the temperature of the heating furnace as the hot milk temperature, and the hot milk temperature is 800°C ~ 1200°C; After that, the first tantalum target blank is taken out from the heating furnace and put into the calendering machine for multi-pass mulching. After each pass mulching, the next batch of mulching is performed by rotating the preset Angle. The total deformation after multi-pass mulching is 70% ~ 90%.
Provide tantalum ingot, the tantalum ingot forging and dairy, after the formation of the tantalum target material blank, and then to the second electrodes in the tantalum target material for the first heat treatment, the three stages the first heat treatment, three phase step heating for thermal insulation and in each stage, so the first heat treatment can be three phases to improve the atoms diffusion ability, In order to reduce the internal microstructure defects caused by forging and emulsion and eliminate the residual stress of the second tantalum target blank. In addition, the step heat treatment of the second tantalum target billet with step heating and heat preservation will also cause the phenomenon of recrystallization inside the second tantalum target billet and increase the content of crystal direction (100) in the subsequent tantalum target. And uniform crystal direction, fine grain (grain size less than or equal to 100 μ m) tantalum leather material.
