Sputtering targets can be divided into planar targets and rotating targets according to their shapes. Planar targets are long targets, square targets, or round targets with a certain thickness, etc., which are made by binding a target blank and a backing plate. During sputtering, the target blank and the substrate are parallel to each other, and an electromagnetic field is formed between the target blank and the substrate. Rotating targets are tubular targets, and an electromagnetic field is formed toward the substrate during sputtering. Planar targets are more versatile, but have a lower utilization rate; rotating targets have a higher utilization rate, but poor coating uniformity.
Advantages Of Rotating Targets
1. Rotating targets have higher material utilization
Rotating targets can evenly consume the target surface during rotation, thereby improving the material utilization of the target, which can usually reach 70%-90%. However, since only one fixed side of the planar target is involved in sputtering, "grooves" or "pits" will be formed during use, resulting in uneven material consumption, and the material utilization rate is generally 30%-40%. For expensive targets (such as precious metals or rare earth materials), rotating targets can significantly reduce costs and improve economic benefits.
2. Rotating targets have better sputtering uniformity
Rotating targets rotate continuously during operation, so that each position on the target surface is evenly exposed to the plasma, forming a more uniform sputtering rate. This has obvious advantages for applications with high requirements for film uniformity (such as displays and semiconductor processes). Planar targets are prone to uneven film thickness due to local over-sputtering, especially in large-area substrates or continuous production.
3. Rotating targets have a longer service life
Since rotating targets consume more uniform material, their service life is usually longer than that of planar targets. This means that under the same working conditions, the replacement frequency of the rotating target is lower, which reduces equipment downtime and improves production efficiency. For some continuous production processes, such as large-area coating and roll-to-roll coating, the rotating target can significantly extend the production cycle and reduce maintenance costs.
4. Rotating targets have higher film quality
The film layer sputtered by the rotating target is denser and more uniform, which is suitable for some applications with extremely high requirements for film quality (such as high-end electronic devices and semiconductor device manufacturing). This is because the rotating target can effectively reduce the defects caused by uneven sputtering on the target surface and improve the quality and consistency of the film layer.
Conclusion
Compared with planar targets, rotary targets have higher material utilization, longer service life, more uniform sputtering effect, and adaptability to large-area and high-volume production. This makes rotary targets an important choice in the field of modern thin film deposition, especially in large-area coating, continuous production, and high-end electronic device manufacturing.