The choice of high performance coating technology: sputtering coating vs vacuum coating

     (1)  Technical characteristics of sputtering coating

      A. Material diversity and coating selection

Sputtering coating technology is notable for its material diversity and the development of multilayer coating technology. Common sputtering materials include aluminum, gold, titanium and so on. These materials show excellent properties in different applications. For example, aluminum has good electrical conductivity and reflection, and is widely used in electronic devices and optical films. Gold is often used in high-end electronic products because of its excellent corrosion resistance and electrical conductivity. Titanium is used in aerospace and medical devices because of its high strength and high temperature resistance. The development of multilayer coating technology makes it possible to deposit multiple layers of different materials on the same substrate, so as to obtain composite coatings with various excellent properties.

     B. Uniformity and density of coating

Sputtering technology can form a uniform and dense coating, which is an important advantage in high-precision applications. Because the material atoms hit the substrate surface with high energy during sputtering, the coating formed is not only uniform and dense, but almost no pores or cracks. This characteristic makes sputtering coating widely used in semiconductor device manufacturing requiring high surface quality.

     C. Application field of sputtering coating

Sputtering coatings are widely used in many fields such as semiconductor devices, optical films and protective coatings. In semiconductor device manufacturing, sputtering coating technology is used to prepare metal interconnect layers, providing excellent electrical conductivity and corrosion resistance. In the field of optics, sputtering coating technology is used to manufacture films with high reflectivity and high transmittance, such as mirrors and filters. In terms of protective coating, sputtering coating technology can form a wear-resistant and corrosion-resistant protective layer on the surface of the substrate, extending the service life of the equipment.

     (2)  Technical characteristics of vacuum coating

     A. Advantages of high vacuum environment

Vacuum coating technology utilizes a high vacuum environment to vaporize the material and deposit it on the substrate surface by heating or ion bombardment from an evaporation source. The advantage of a high vacuum environment is that impurities and pollutants in the air can be greatly reduced, and the purity and quality of the coating can be improved. Evaporation source heating is often used for high-precision film fabrication, while ion bombardment can further enhance the adhesion and densification of the coating.

     B. Adhesion and uniformity of the coating

The coating in vacuum environment, because there is no air obstruction, the material particles can be uniformly deposited on the surface of the substrate to form a uniform coating. In addition, during ion bombardment, ions impact the substrate surface with high energy, which can not only deposit materials, but also clean the substrate surface to form a firm adhesive layer. This characteristic makes vacuum coating widely used in high performance coating and industrial coating.

     C. Application field of vacuum coating

Vacuum coating is widely used in decorative coating, industrial coating and high performance coating. In decorative coating, vacuum coating can form a variety of colors and textures of coating, widely used in jewelry and high-end consumer goods. In industrial coating, vacuum coating technology is used to manufacture wear-resistant, corrosion-resistant tools and mechanical parts. In the field of high performance coatings, vacuum coatings provide high hardness, low coefficient of friction coating, significantly improve the service life and performance of parts.

     (3) Comparison of sputtering coating and vacuum coating

     A. Comparison of process temperature and environmental requirements

Sputtering coatings are usually performed at lower temperatures, which makes them suitable for temperature-sensitive substrate materials. The vacuum coating needs to be carried out in a high vacuum environment, which has higher requirements for the equipment and process environment.

     B. Comparison of coating thickness and quality

Sputtering enables precise control of coating thickness for applications requiring high precision and meticulous control. Vacuum coating is more suitable for large area coating and high performance coating applications due to its uniform coating quality.

     C. Comparison of production efficiency and cost

Sputtering coating is suitable for large-scale continuous production, high production efficiency, but high equipment cost. The initial equipment investment of vacuum coating is large, but its coating quality is superior, and it is suitable for the production of high value-added products.

Practical application cases of sputtering and vacuum coating in industry

     A. Application cases in the electronics industry

1. Sputtering coating in integrated circuit manufacturing

In the process of IC manufacturing, sputtering coating technology is widely used in the preparation of metal interconnect layer. The fabrication of an integrated circuit (IC) requires depositing a series of metal layers on a semiconductor substrate that serve as conductive paths to connect different circuit components. The sputtering coating technology can be carried out in a low temperature environment, avoiding the damage that may be caused to the semiconductor substrate by high temperature. In addition, the sputtering coating enables the formation of a coating of precise and uniform thickness, which is essential for the high-density interconnection of microelectronic devices.

Material selection: Aluminum, copper and titanium are commonly used sputtering materials. Among them, aluminum was widely used in early IC manufacturing because of its good electrical conductivity and relatively low cost. With the development of technology, copper has gradually replaced aluminum because of its lower resistance and better electromobility, and has become the mainstream material for modern IC manufacturing. In addition, titanium, as a transition layer material, can improve the adhesion between copper and the substrate and prevent the diffusion of copper.

Process flow: The typical sputtering coating process includes target selection, substrate cleaning, vacuum cavity preparation, plasma generation and sputtering deposition. Under the action of plasma, the atoms on the surface of the target are knocked out and a dense metal layer is formed on the substrate.

2. Vacuum coating in display film technology

The development of display technology cannot be separated from the support of vacuum coating technology. Whether it is liquid crystal display (LCD), organic light-emitting diode (OLED) or the emerging quantum dot display (QD-LED), vacuum coating technology has played an important role in it.

Advantages of high vacuum environment: Coating in a vacuum environment can effectively avoid the impact of impurities in the air on the quality of the film and ensure the purity and uniformity of the coating. The vacuum coating process enables highly accurate film thickness control, which is essential for the manufacture of transparent electrodes and light-emitting layers in displays.

Application example: In the manufacture of OLED displays, vacuum evaporation technology is used to deposit layers of organic materials and metal cathodes. These layers are typically only tens of nanometers thick, requiring extremely high uniformity and precision. Vacuum coating technology can not only meet these requirements, but also achieve complex display structure through multi-layer superposition, improve the display effect and device performance.

     B. Application cases in aerospace industry

1. Sputtering coating in turbine blade coating

Turbine blade is the core component of aero engine, its working environment is extremely harsh, high temperature, high pressure and strong corrosive gas put forward a severe test to blade materials. By depositing a layer of high hardness and high wear resistance on the surface of the blade, sputtering coating technology can significantly improve the service life and performance of the blade.

Material selection: Commonly used coating materials include chromium, aluminum titanium alloy and carbide. These materials maintain stable structure and properties at high temperatures, providing excellent oxidation and corrosion resistance.

Process flow: The sputtering coating process of turbine blades includes surface pretreatment, target selection, vacuum cavity preparation, plasma generation and sputtering deposition. Under the action of plasma, the atoms on the surface of the target are knocked out, and a uniform and dense coating is formed on the surface of the blade.

2. Vacuum coating in spacecraft surface protection

As spacecraft operate in space, they are subjected to intense radiation from the sun, collisions with space particles, and extreme temperature changes. These environmental factors place extremely high demands on the materials on the spacecraft surface. Vacuum coating technology can form a high-performance protective layer on the surface of spacecraft to improve its durability and reliability.

Advantages of high vacuum environment: vacuum coating technology can be carried out in a high vacuum environment, effectively avoiding the impact of pollutants in the earth's atmosphere on the quality of the coating. This feature makes vacuum coating the preferred technology for spacecraft surface treatment.

Application example: In the spacecraft surface protection, the commonly used vacuum coating materials include aluminum, silver and gold. These materials not only have excellent reflection performance, which can effectively reduce the impact of solar radiation on spacecraft, but also have good corrosion resistance and wear resistance, and can maintain stable performance in the space environment for a long time.

    C. Application cases in the optical industry

1. Sputtering coating in lens coating

The performance of optical lenses directly affects the imaging quality of optical instruments. Sputtering coating technology is widely used in the manufacture of optical lenses. By deposting a high-precision coating on the surface of the lens, the transmittance and reflectivity of the lens can be significantly improved.

Material selection: Commonly used coating materials include titanium dioxide, silicon dioxide and aluminum. These materials have excellent optical properties in the spectral range of different wavelengths, enabling the design of thin films with specific optical properties as required.

Process flow: The sputtering coating process of optical lenses includes target selection, substrate cleaning, vacuum cavity preparation, plasma generation and sputtering deposition. Under the action of plasma, the atoms on the surface of the target are knocked out, and a uniform and dense coating is formed on the surface of the lens.

2. Vacuum coating in laser devices

Laser devices occupy an important position in the field of modern optics and electronics, and their performance directly affects the efficiency and stability of related equipment. The vacuum coating technology plays a key role in the manufacture of laser devices, which can significantly improve the output efficiency and stability by deposition of high reflectivity thin films on the surface of laser devices.

Advantages of high vacuum environment: vacuum coating technology can be carried out in a high vacuum environment, effectively avoiding the impact of impurities in the air on the quality of the film, to ensure the purity and uniformity of the coating. High quality vacuum coating can not only improve the reflectivity of laser devices, but also enhance their durability and stability.

Application example: In the manufacture of laser devices, the commonly used vacuum coating materials include gold, silver and multilayer dielectric materials. These materials can provide highly reflective films in different wavelength ranges, significantly improving the output efficiency and stability of laser devices.