Sputtering is to use the ions generated by ion source to accelerate the aggregation into high-speed ion flow in vacuum to bombard the solid surface, so that the atoms on the solid surface leave the target and deposit on the surface of the base material, so as to form nano (or micron) film. The solid body bombarded is called the sputtering target. Sputtering coating is the basic means of preparing functional thin films in the fields of integrated circuit, flat panel display (including LIQUID crystal display and touch screen, etc.), thin film solar battery and light emitting diode (LED), etc. Sputtering target has become an indispensable basic material in these fields.
With the continuous improvement of the requirements for the comprehensive performance of electronic products and the use of the environment, the performance of sputtering target material is also put forward higher and higher requirements. Although molybdenum has become an ideal electrode and wiring material for flat panel display, thin film solar cell and semiconductor barrier material, it is found that there are still problems in corrosion resistance (discoloration) and density (film stripping). The study and practice show that adding niobium and other alloying elements into molybdenum sputtering target can balance the properties of sputtering films such as specific impedance, stress and corrosion resistance, and it is more and more popular. At present, the mo nb alloy spatter target has been applied in the preparation of functional films such as touch screen (mobile phone, public field display, etc.) and LIQUID crystal display, showing significant advantages and broad application prospects.
Generally, the preparation process of molybdenum and niobium alloy sputtering target material includes: 1) smelting casting process a certain proportion of molybdenum and niobium raw materials are melted, and then the alloy molten liquid is poured into the mold to get the ingot, and then the target material is made by heat treatment, forging, extrusion and emulsion. The problems of this process are: ingot inevitably has casting defects, such as shrinkage cavity, shrinkage porosity, inclusion, segregation, and so on, and ingot coarse grain, resulting in reduced coating efficiency and film quality decline, if further processing, low rate of finished products, high cost; Because molybdenum and niobium are both high melting point metals, vacuum arc melting or vacuum electron beam melting is usually used, which requires high equipment conditions and high cost. It is difficult to obtain the target material of molybdenum niobium alloy with uniform composition, even if the secondary remelting process is used, the composition uniformity is difficult to meet the requirements, resulting in the uniformity of the film layer.
