【New process announcement】Two-stage reactive sputtering method

Dahyoung has newly developed the "two-stage reactive sputtering method" technology. By separating the interaction between sputtering and reactive gas, it can effectively improve the shortcomings of the reactive sputtering process while maintaining the high film quality and quality of the sputtering process. In addition to the advantages of large area uniformity, the process has higher stability and a high deposition rate comparable to that of the sputtering target metal!

Technology Introduction

The sputtering and reaction are divided into two stages [1]: the cathode target sputters the target particles, which adhere to the surface of the substrate to form an ultra-thin metal film with a thickness of about 1 to 4 Å, and generate reactive gas plasma in a closed area to make reactive gases such as oxygen and nitrogen gas radicals react with the ultra-thin metal on the surface of the substrate, and form a variety of reactants, such as SiOx, NbxOy or SixNy compounds through the mixed gas ratio. This is the nucleation stage of film growth. Repeat the above process to make the target particles continue to react and condense to form a dielectric film. By separating the interaction between sputtering and reactive gas, this eliminates charge accumulation, arcing and process instability, and achieves a high deposition rate. This process method is called two-stage reactive sputtering method [2], as shown in Figure 1.

Figure 1. The intention of the two-stage reactive sputtering process

In addition to the field of vapor deposition optics, Dayong Vacuum has developed its own two-stage reactive sputtering equipment to introduce the characteristics of the sputtering process into the optics field. The film characteristics of traditional reactive sputtering are shown in Table 1:

Table 1. Comparison of evaporation and reactive sputtering characteristics

However, reactive sputtering can easily cause target poisoning and reduce the plating rate, and arcing can easily occur after accumulated charges, which can cause film defects, as shown in Figure 2:

Figure 2. Schematic diagram of film defects caused by Arcing

Dahyoung uses the two-stage reactive sputtering method to properly solve the shortcomings of reactive sputtering with low deposition rate and easy arcing due to target poisoning, and further improve the optical film to "high deposition rate" and "high film quality. "High stability", and overcome the limitation of non-planar substrates to a certain extent, so that uniform optical films can be prepared from curved substrates. This feature is very suitable for automotive lenses in the self-driving industry. Figure 3 shows the transmittance curve of single-layer films with high and low refractive index prepared by Dayong Vacuum using the two-stage reactive sputtering method:

Figure 3. SiO2, Nb2O5 transmittance curve

The anti-reflective film coated with this is shown in Figure 4:

Figure 4. Reflectance curve of anti-reflective film made by two-stage reactive sputtering

In the future, Dahyoung will continue to deepen the field of sputtering optics, carry out more front-end process research and development, and enter the self-driving car industry, with the best performance of sputtering technology, to provide customers with high-quality optical film coating options.