PVD (Physical Vapor Deposition) technology is one of the main technologies for preparing thin film materials. Physical methods are used under vacuum conditions to vaporize a material into gaseous atoms, molecules or partial ionization into ions, and pass through low-pressure gas (or plasma) Process, the technology of depositing thin film materials with special functions such as anti-reflection, reflection, protection, conduction, magnetic permeability, insulation, corrosion resistance, oxidation resistance, radiation protection, decoration, etc. on the surface of the substrate material. The substances used to prepare thin film materials are called PVD coating materials. Sputtering coating and vacuum evaporation coating are the two most mainstream PVD coating methods.
sputter coating
The sputtering target has the characteristics of high purity, high density, multi-component, uniform grain, etc. It is generally composed of a target blank and a backing plate. The target blank is the core part of the sputtering target and is the target material bombarded by high-speed ion beams. After the target blank is hit by ions, its surface atoms are scattered by sputtering and deposited on the substrate to form an electronic thin film. Due to the low strength of high-purity metals, sputtering targets need to be sputtered in a high-voltage, high-vacuum machine environment. The sputtering target blank of ultra-high-purity metal needs to be joined with the backplate through different welding processes. The backplate mainly plays the role of fixing the sputtering target, and needs to have good electrical and thermal conductivity.
According to the different raw materials used, sputtering targets can be divided into metal/non-metal elemental targets, alloy targets, compound targets, etc. The sputtering coating process has good repeatability and controllable film thickness, and a thin film with uniform thickness can be obtained on a large-area substrate material. It has become one of the main technologies for preparing thin-film materials. Various types of sputtering thin-film materials have been widely used. Therefore, the demand for sputtering targets, a functional material with high added value, is increasing year by year, and sputtering targets have also been It has become the most widely used PVD coating material in the market.
Ultra-high-purity metals and sputtering targets are an important part of electronic materials. The sputtering target industry chain mainly includes metal purification, target manufacturing, sputtering coating and terminal applications. Among them, target manufacturing and sputtering coating The link is the key link in the entire sputtering target industry chain.
The upstream metal purification is mainly purified from the key metal ores in nature. The general metal can reach the purity of 99.8%, and the sputtering target needs to reach the purity of 99.999%.
The target manufacturing process first needs to carry out process design according to the performance requirements of downstream applications, and then repeats plastic deformation and heat treatment to control key indicators such as grain and crystal orientation, and then undergoes water cutting, mechanical processing, metallization, and supersonic testing. Ultrasonic cleaning and other processes.
The processes involved in the manufacture of sputtering targets are fine and numerous, and the process management and manufacturing process level will directly affect the quality and yield of sputtering targets.
This link is the link with the highest requirements for production equipment and technical processes in the sputtering target industry chain. The quality of the sputtering film has an important impact on the quality of downstream products.
In the sputtering coating process, the sputtering target needs to be installed in the machine to complete the sputtering reaction. The sputtering machine is highly specialized and has high precision. The market has long been monopolized by American and Japanese multinational groups. The main equipment providers include AMAT ( United States), ULVAC (Japan), ANELVA (Japan), Varian (United States), ULVAC (Japan) and other well-known enterprises in the industry.
Vacuum Evaporation Coating
Vacuum evaporation coating refers to a technology that obtains a thin film by heating and evaporating a certain substance by an evaporation source under vacuum conditions to deposit it on the surface of the substrate material. The vaporized substance is called vapor deposition material. Evaporation coating was first proposed by M. Faraday in 1857. After more than 100 years of development, it has become one of the mainstream coating technologies.
The vacuum evaporation coating system generally consists of three parts: a vacuum chamber, an evaporation source or an evaporation heating device, a substrate placement and a heating device for the substrate. In order to evaporate the material to be deposited in a vacuum, a container is required to support or contain the evaporative material, while the heat of evaporation needs to be provided to bring the evaporative material to a temperature high enough to generate the desired vapor pressure.
Schematic diagram of the working principle of vacuum evaporation coating
Vacuum evaporation coating technology has the characteristics of simplicity and convenience, convenient operation and fast film forming speed. It is a widely used coating technology, mainly used in the coating of optical components, LEDs, flat panel displays and semiconductor discretes. Vacuum coating materials can be mainly divided into metal/non-metal particle evaporation materials, oxide evaporation materials, fluoride evaporation materials, etc. according to their chemical composition.
Types of Evaporation Materials
Metal and non-metal particles
Aluminum evaporation material, nickel evaporation material, copper evaporation material, silver evaporation material, titanium evaporation material, silicon evaporation material, vanadium evaporation material, magnesium evaporation material, tin evaporation material, chromium evaporation material, indium evaporation material, silver copper evaporation material, gold evaporation material Evaporation material, microcrystalline silver powder, etc.
oxide
Titanium-tantalum alloy, zirconium-titanium alloy, silicon-aluminum alloy, aluminum oxide, zirconium dioxide, titanium pentoxide, quartz ring, quartz plate, erbium oxide, lanthanum titanate, etc.
Fluoride
Magnesium fluoride, dysprosium fluoride, lanthanum fluoride, etc.
The main process flow of vapor deposition materials includes mixing, raw material pretreatment, molding, sintering and testing. The prepared raw materials are mechanically mixed to achieve uniform dispersion (mixing), and then treated at room temperature or high temperature (raw material pretreatment) to improve the purity of the material, refine the particle size, stimulate the reactivity of the material, and reduce the sintering temperature of the material. The material is then mechanically processed to the required specifications (forming). After molding, the material is sintered at high temperature, so that the solid particles of the green ceramic body are bonded to each other, and finally become a process (sintering) of a dense polycrystalline sintered body with a certain microstructure. After the production of the evaporated material, use the evaporation coating equipment to test the performance of the material to check whether the product performance index is qualified.
Process flow of vacuum coating material
Raw material powder - batching - mixing - raw material pretreatment - forming - pre-burning - vacuum sintering - sorting - vacuum packaging
Comparison of sputter coating and evaporation coating:
The sputtering coating process has good repeatability and controllable film thickness, and a thin film with uniform thickness can be obtained on a large-area substrate material. It has become one of the main technologies for preparing thin-film materials. Various types of sputtering thin-film materials have been widely used. Therefore, the demand for sputtering targets, a functional material with high added value, is increasing year by year, and sputtering targets have also been It has become the most widely used PVD coating material in the market.
Evaporation coating is simple and convenient, easy to operate, and fast to form a film. From the perspective of process manufacturing, the manufacturing complexity of evaporation materials is much lower than that of sputtering targets, and evaporation coatings are often used for the coating of small-sized substrate materials.
Competitive Landscape
Flat panel displays mainly include liquid crystal display (LCD), plasma display (PDP), electroluminescence display (EL), field emission display (FED), organic light emitting diode display (OLED) and touch control (TP) developed on the basis of LCD. ) to display the product.
Among them, the market application is dominated by liquid crystal displays. Coating is the basic link of the modern flat panel display industry. In order to ensure the uniformity of large-area film layers, improve productivity and reduce costs, almost all types of flat panel display devices use a large number of coating materials to form various functional films. PVD coating materials are mainly sputtering targets, and many properties of flat-panel displays, such as resolution and light transmittance, are closely related to the properties of sputtered films.
The flat panel display industry mainly uses PVD coating materials in the production of display panels and touch screen panels. Among them, in the production process of flat-panel display panels, the glass substrate is subjected to multiple sputtering coatings to form ITO glass, which is then coated, processed and assembled for the production of LCD panels, PDP panels and OLED panels. For the production of touch screens, ITO glass needs to be processed, coated to form electrodes, and then assembled with protective screens and other components.
In addition, in order to realize the functions of anti-reflection and anti-shadowing of flat panel display products, it is also possible to increase the coating of the corresponding film layer in the coating process.
In the OLED process, the two stages of TFT array and cell forming contain many complex processes. The key equipment (TFT equipment, evaporation equipment and packaging equipment) is almost monopolized by Japan, South Korea and the United States, and the equipment is expensive, among which evaporation deposition equipment Equipment is the core link in the entire panel production process, which directly affects the yield and quality of finished products. Currently, the evaporation equipment on the market is monopolized by Japan and South Korea.
The PVD coating process originated abroad. In the early stage of industry development, the matching of coating equipment and coating materials were mainly from foreign manufacturers. The coating materials of foreign PVD coating material manufacturers have experienced long-term running-in with the coating equipment and coating processes of downstream customers. The performance indicators have been well matched with customers, and they have a strong first-mover advantage. Therefore, for a long time, the global PVD coating Material development and production are mainly concentrated in a few companies in the United States, Japan and Germany, with a high degree of industrial concentration.
High-purity sputtering targets belong to a typical technology-intensive industry, and the R&D and production equipment is highly specialized. To a certain extent, the regional agglomeration of the global semiconductor industry has created high-purity sputtering
High concentration of shooting target manufacturers. Since its birth, high-purity sputtering target manufacturers represented by the United States and Japan have implemented strict confidentiality measures on core technologies, resulting in the sputtering target industry showing obvious regional agglomeration characteristics on a global scale. Mainly concentrated in the United States and Japan.
Globally, multinational companies such as Nippon Mining Metals, Honeywell, Tosoh, Praxair, Sumitomo Chemical and other multinational companies with strong financial strength, leading technology and rich industrial experience occupy the leading position in the global high-purity sputtering target industry. It belongs to the traditional strong enterprises of sputtering targets, occupies most of the market share of the global sputtering target market, and dominates the development of the global sputtering target industry.
