Nickel-vanadium sputtering target is in the process of preparing nickel-vanadium alloy, adding vanadium to the nickel melt, so that the prepared alloy is more conducive to magnetron sputtering, combining the advantages of nickel sputtering target and vanadium sputtering target. With the progress of society and the development of semiconductor industry, the demand for nickel-vanadium targets in electronics and information, integrated circuits, displays and other industries is increasing.

Sputtering targets are mainly used in information storage, integrated circuits, displays, automotive rear-view mirrors and other industries, mainly for magnetron sputtering various thin film materials. Magnetron sputtering is a method of preparing thin film materials. The ions generated by ion sources are accelerated to gather into high-speed ion flow in vacuum. The accelerated particle flow bombards the surface of the object to be deposited with the thin film. The bombarded solid is the raw material for deposition of the film by sputtering method, which is called the sputtering target.

In the production of integrated circuits, pure gold is generally used as the surface conductive layer, but gold and silicon wafers are easy to generate AuSi low melting point compounds, resulting in the interface bond between gold and silicon is not strong, people proposed to add a bonding layer on the surface of gold and silicon wafers, commonly used pure nickel as the bonding layer, but the nickel layer and gold conductive layer will also form diffusion, so there is a need for a barrier layer. To prevent diffusion between the gold conductive layer and the nickel bonding layer. Barrier layer needs to use high melting point metal, but also to withstand a larger current density, high purity metal vanadium can meet the requirements, so in the production of integrated circuits will use nickel sputtering target, vanadium sputtering target, gold sputtering target and so on.

Nickel-vanadium sputtering target is in the process of preparing nickel-vanadium alloy, adding vanadium to the nickel melt, so that the prepared alloy is more conducive to magnetron sputtering, combining the advantages of nickel sputtering target and vanadium sputtering target, can complete the sputtering nickel layer (bonding layer) and vanadium layer (barrier layer). Nickel-vanadium alloy is non-magnetic, which is conducive to magnetron sputtering, and basically replaces pure nickel sputtering targets in the electronics and information industry.

First, the characteristics of nickel vanadium alloy sputtering target requirements

Sputtering nickel-vanadium target requires high purity, less impurities, uniform chemical composition, no segregation, no porosity, uniform grain structure, grain size is micron, a single sputtering target requires the grain size difference as small as possible, so that it is not easy to produce discharge in magnetron sputtering, and the magnetron sputtering film is uniform.

Step 1: Purity

Sputtering target is first of all to high purity, because the impurities in the sputtering target has the greatest impact on the performance of the magnetron sputtering film, so the impurity content in the sputtering target should be reduced as much as possible, many semiconductor or electronic product manufacturing companies at home and abroad put forward high requirements for the impurity content of the sputtering target. 2. Impurity content

The impurities in the sputtering target are strict, the content of Cr, Al, Mg impurities in the nickel-vanadium alloy sputtering target does not exceed 10ppm, more than 10ppm, the corrosion performance becomes worse. The content of U and Th does not exceed 1ppb, and the content of Pb and Bi is less than 0.1ppb, exceeding this content, it will have an adverse effect on the electronic charge, and there will be a failure. The N content is between 1-100ppm, the N content increases, and the corrosion performance is poor, so the content of impurities should be strictly controlled.

3. Density

Sputtering targets have very strict requirements for internal pores, because the pores in the target will affect all aspects of the performance of the sputtered film, and the abnormal discharge generated during the magnetron sputtering process will affect the photoelectric performance of the magnetron sputtering film, so the target is required to have a high density. In addition, high-density and high-strength sputtering targets can better withstand the thermal stress generated in magnetron sputtering. The preparation process of nickel-vanadium sputtering targets is generally divided into powder metallurgy and melting. The sputtering target prepared by powder metallurgy has many pores and low density. Smelting methods are divided into ordinary smelting and vacuum smelting. Ordinary melting method, in the melting process, the gas in the atmosphere is easy to enter the melt, resulting in the melting of the ingot gas content can not meet the requirements of the sputtering target, so the preparation of nickel-vanadium sputtering target alloy is generally used vacuum melting method, which can ensure that there is no porosity inside the material.

4. Grain size and grain size distribution

Nickel-vanadium targets need to go through multiple cold and hot processing processes, and the prepared target blank has polycrystalline structure, and the grain size is strictly required, and the grain size should be controlled within 100 microns. From the perspective of sputtering performance, for magnetron sputtering targets with the same chemical composition, the sputtering rate of small grains is faster than that of large grains, and the more uniform the grains inside the target, the more uniform the thickness of the film sputtered on the silicon wafer.

Second, preparation of nickel-vanadium alloy target

In the nickel-vanadium alloy, a slight change in the amount of vanadium will significantly change the performance of the nickel-vanadium alloy, so that the Ni-V alloy can not be obtained through subsequent processing of sputtering targets. Typical nickel-vanadium alloy composition is Ni-7V, the production of high-purity Ni-V alloy, the key is:

Must use high-grade metal raw materials nickel and vanadium, the purity must be above 95wt%, of which the purity of nickel raw materials reached 4N5 (99.995wt%) or even 5N is no problem, but the purity of vanadium raw materials is generally only 2N5-3N (99.5wt%-99.9wt%), the purity of vanadium limits the purity of nickel-vanadium alloy.
The melting point of vanadium is 1919± 2℃, which is a refractory metal, and the melting point of nickel and vanadium is very different (about 336℃), so it is difficult to prepare a target ingot with uniform composition by general melting methods. In special applications, the ingots of nickel and vanadium are first obtained by vacuum melting methods (electron beam or vacuum arc remelting (VAR) or vacuum induction melting (VIM)), and the total purity of the alloy ingots is improved by repeated vacuum melting.
3) The introduction of impurity elements is strictly controlled during the preparation process. 

Adding 7% vanadium to nickel has the following effects:

1. Improve hardness and strength: Vanadium can form a solid solution with nickel, which enhances the hardness and strength of the alloy. At high temperatures, vanadium can form stable carbides and borides, further improving the hardness and strength of the alloy.

2. Improve corrosion resistance: Vanadium can improve the corrosion resistance of the alloy, especially in oxidation and reducing environments. The role of vanadium in nickel alloys is similar to that of chromium in stainless steel.

3. Improve high temperature resistance: Vanadium can improve the high temperature strength and stability of nickel alloy, so that it shows excellent performance at high temperatures. The addition of vanadium can effectively inhibit the grain growth of the alloy, reduce grain boundary cracks and fractures, and improve the fracture toughness of the alloy at high temperature.

4. Improve oxidation resistance: Vanadium can promote the formation of a dense oxide layer on the surface of the alloy, enhance the oxidation resistance of the alloy, inhibit the spalling and shedding of the oxide layer, and extend the service life of the alloy.

Third, the characteristics and applications of nickel-vanadium alloy targets

Nickel-vanadium alloy targets are mainly used in solar energy industry, electronics industry and other fields, nickel-vanadium targets

Application and required purity.

1. Optical storage;

2. Solar thin film battery;

    

3. Flat panel display coating;

    

4. Electronics and semiconductors;

    

5. Architectural glass;