Sputtering coating and vacuum evaporation coating
IKS PVD vacuum coating machine and target materials
PVD (Physical Vapor Deposition) technique is one of the main technology of preparation of thin film materials, under the condition of vacuum with Physical method, some material gasification into gaseous atoms, molecules or partial ionization ion, and through the low pressure gas (or plasma) process, the Deposition with anti-reflection, reflecting on the surface of substrate material, protect conductive, permeability, insulation, anti corrosion and oxidation resistance, radiation protection, decoration and so on special function of the technology of thin film materials. The material used to prepare the thin film material is called PVD coating material. After years of development, PVD coating technology is widely used in the fields of electronics, optics, machinery, building and materials. Sputtering coating and vacuum evaporation coating are the two most mainstream PVD coating methods.
Sputtering coating and sputtering target material
Sputtering technology, use ions from an ion source to accelerate in a high vacuum to form a high-velocity ion beam that bombards the solid surface. The atoms on the solid surface exchange kinetic energy, causing the atoms on the solid surface to leave the solid and deposit on the substrate surface to form a thin film material. The solid material being bombarded is the raw material of the film deposited by sputtering method, which is called sputtering target material.
Sputtering target material is characterized by high purity, high density, multiple components and uniform grain, and is generally composed of target blank and back plate. The target billet belongs to the core of sputtering target material and is the target material of high speed ion beam bombardment. When the target billet is hit by ions, the surface atoms are sputtered and deposited on the substrate to make electronic films. Due to the low strength of high-purity metal, sputtering target material needs to complete the sputtering process in the machine environment with high voltage and vacuum. The sputter target of ultra-high pure metal joined with the back plate through different welding processes. The back plate plays the role of fixing the sputtering target, and needs to have good electrical and thermal conductivity.
Sputtering targets can be classified into metal/non-metal single target, alloy target, compound target, etc. Sputtering coating process, good repeatability, film thickness can be controlled, can be obtained in large area on the substrate material thickness of thin film, the preparation of the thin film has high purity, good compactness and strong bonding force with substrate material advantages, has become one of the main technology of preparation of thin film materials, various types of sputtering film materials have been widely used, therefore, of sputtering target materials that functional materials with high added value demand increased year by year, sputtering target material market are also has become the largest PVD coating material.
Sputtering technology originated in 1842 when grove discovered cathode sputtering in the laboratory. When he studied the corrosion of the cathode of the tube, he found that the cathode material migrated to the wall of the vacuum tube. However, the physical mechanism of sputtering was not clear because of the backward experimental equipment. By the early 20th century, sputtering technology was applied only to materials with strong chemical activity. After the 1970s, magnetron sputtering technology really emerged, and commercial sputtering equipment emerged and was applied to small-scale production. In the 1980s, sputtering technology really entered the era of industrial mass production. Then came to the 21st century, various of new sputtering technologies come out, led to the brilliant sputtering technology. Now sputtering technology has become a rather mature process, and widely used in semiconductor, photovoltaic, display and other industries.
Ultra-high purity metals and sputtering target materials are important components of electronic materials. The sputtering target industry chain mainly includes metal purification, target material manufacturing, sputtering coating and terminal application, among which target manufacturing and sputtering coating are key links in the whole sputtering target industry chain.
The upstream metal purification is mainly carried out from the key metal ore in the nature, and the general metal can achieve the purity of 99.8%, and the sputtering target material needs to achieve the purity of 99.999%. The manufacturing process of target material first needs to carry out process design according to the performance requirements of the downstream application field, and then carry out repeated plastic deformation and heat treatment to control the key indicators such as grain and orientation, and then go through water cutting, mechanical processing, metallization, ultrasonic test, ultrasonic cleaning and other processes. The manufacturing process of sputtering target is very detailed and various. The process flow management and manufacturing process level will directly affect the quality and yield of sputtering target. The quality of sputtering films has an important influence on the quality of downstream products. In the process of sputtering coating, sputtering target material needs to be installed in the machine platform to complete the sputtering reaction. The sputtering machine platform has strong specificity and high precision.
The terminal application is made into end-user oriented products according to various market demands, including solar cells, smart phones, tablet computers, household appliances and other terminal consumer electronic products. In the application field of sputtering target materials, semiconductor chips set extremely harsh standards for metal material purity and internal microstructure of sputtering target materials. Therefore, semiconductor chips have the highest requirements for sputtering target materials, which usually require more than 99.9995% (5N5) and are the most expensive. Compared with semiconductor chips, planar displays and solar cells have a slightly lower requirement for purity and technology of sputtering target materials, which are required to reach 99.999%(5N) and 99.995%(4N5) and above respectively. However, with the increase of the target size, higher requirements are put forward for the indexes of welding bonding rate and flatness of sputtering target.
Vacuum evaporation coating and evaporation material
Vacuum evaporation coating is a kind of technology to obtain the thin film by heating and evaporating some material from the evaporation source and depositing it on the surface of substrate material under vacuum condition. The evaporated material is called the vapor 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: vacuum chamber, evaporation source or evaporation heating device, substrate placement and substrate heating device. In order to vaporize the material to be deposited in a vacuum, a vessel is required to hold or hold the vaporization, and a heat of evaporation is provided to bring the vaporization to a high enough temperature to produce the desired vapor pressure.
Vacuum evaporation coating technology is characterized by simple convenience, easy operation and fast film forming speed. It is a widely used coating technology, mainly used in optical components, LED, flat panel display and semiconductor splitter coating. According to the chemical composition, the vacuum coating material can be divided into metal/non-metal granule vaporization material, oxide evaporative material and fluoride evaporative material.
The main technological processes of evaporation materials include mixing, raw material pretreatment, molding, sintering and inspection. The prepared raw materials are mixed mechanically to achieve uniform dispersion (mixing), and then processed at room temperature or high temperature (raw material pretreatment) to improve the purity of the materials, refine the particle size, stimulate the reactivity of the materials and reduce the sintering temperature of the materials. The material is then machined to the required specification (molding). After forming, the material is sintered at a high temperature, which makes the solid particles of the green ceramics bond with each other, and finally becomes a process of dense polycrystalline sinter with a certain microstructure (sintering). After the production of the evaporation materials, the evaporative coating equipment is used to inspect the properties of the materials and check whether the product performance indicators are qualified.
Sputtering deposition and evaporation coating contrast: sputtering coating process good repeatability, film thickness can be controlled, can be obtained in large area on the substrate material thickness of thin film, the preparation of the thin film has high purity, good compactness and strong bonding force with substrate material advantages, has become one of the main technology of preparation of thin film materials, various types of sputtering film materials have been widely used, therefore, of sputtering target materials that functional materials with high added value demand increased year by year, sputtering target material market are also has become the largest PVD coating material. The evaporation coating is simple and convenient, easy to operate and the film forming speed is fast. From the point of view of technological manufacturing, the manufacturing complexity of evapotranspiration is much lower than that of sputtering target.