Aluminum Sputtering Targets: Properties, Applications, and Benefits

The aluminum target is one of the sputtering targets used in the vacuum coating industry. It is a product of high-purity aluminum after a series of processing. It has a specific size and shape. The high-purity aluminum material is installed on a vacuum coating machine and sputtered into a film.

Classification of aluminum targets

Aluminum targets are divided into planar aluminum targets and rotating aluminum targets:Planar aluminum targets are flakes, such as round and square.

The rotating aluminum target is tubular and has high utilization efficiency, but it is not easy to process. It takes high-purity aluminum extrusion, stretching, straightening heat treatment, machining and other processing procedures to finally produce the finished aluminum rotating target.

Production of aluminum target

1. Production and purification of aluminum:Aluminum is obtained by extracting Al2O3 from bauxite and electrolyzing it in molten cryolite. The purity is generally above 99%. However, aluminum with such purity cannot be used as a raw material for the production of aluminum targets. The first and most important requirement is high purity. The high-purity aluminum used in the aluminum target is produced by segregation method, three-layer electrolysis method or combined regional smelting method, and the price is more expensive than industrial pure aluminum 99.7. There are many, and the highest purity in China is around 99.9999% (6N).

2. Deformation treatment of aluminum target:With high-purity aluminum ingots as raw materials, the raw materials are forged, rolled, and heat-treated to make the grains in the aluminum ingots smaller and denser to meet the requirements of aluminum targets for sputtering.

3. Machining the high-purity aluminum material after deformation treatment. The processing of aluminum target requires high precision and high surface quality. It is enough to process the target size required by vacuum coating machine. Aluminum target and coating machine are mostly based on threaded connection.

The appliaction of aluminum target

Suitable for DC two-pole sputtering, three-pole sputtering, four-stage sputtering, radio frequency sputtering, facing target sputtering, ion beam sputtering, magnetron sputtering, etc., can be coated with reflective film, conductive film, semiconductor film , Capacitor film, decorative film, protective film, integrated circuit, display, etc. Compared with other targets, the price of aluminum target is lower, so aluminum target is the preferred target material under the premise of satisfying the function of the film layer.

Advantages of high-purity aluminum tube sputtering targets

Sputtering targets for PVD are one of the most important raw materials in the production and processing of semiconductor chips. The most used sputtering targets are high-purity aluminum and ultra-high-purity aluminum alloy targets. High-purity aluminum with a purity of up to 99.999% has good conductivity and fast signal transmission speed, so it is made into a target material, and it is made into thin-film wires of thin-film transistors in LCDs through vacuum sputtering, which plays the role of signal transmission.

According to the principle of sputtering process, the finer the grain of the target material, the more uniform the composition structure, the more concentrated the orientation, the smaller the surface roughness of the target material, and the better the quality of the film formed on the silicon wafer by physical vapor deposition. Therefore, The target requires a fine-grained structure, and the average grain size is required to be less than 150 μm.

Because the original grain size of high-purity aluminum is coarse, as much as 1500-3000 μm, it is very difficult to reduce the grain size to less than 150 μm in the subsequent extrusion deformation process, and it will not meet the requirements if there is a slight deviation. For this reason, in order to make the high-purity aluminum grain size within 150 μm, certain methods must be adopted in the early stage to reduce the original high-purity aluminum grain size to within 1000 μm, so as to ensure that the grain size meets the requirements for subsequent extrusion into tubes.