By Liu Qiang, China National Chemical Information Center

With the gradual maturing of the fifth-generation mobile communication technology (5G technology) and its industry, the applications of the technology will become wider in various fields. By 2030, direct and indirect output driven by 5G are expected to reach RMB6.3 trillion and RMB10.6 trillion in China, respectively.

5G Industrial Chain

   Upstream industries: including chips, optical devices, and RF devices. Among them, chips are mainly dependent on importing. However, driven by 5G technology, Huawei and ZTE have made great progress in research and development of chips in recent years, which is expected to change the situation in the future.

   Midstream industry: including base stations, transmission equipment, and base station antennas. The segment is crucial to the full coverage of 5G, so huge investments have been put in especially in the construction of base stations.

   Downstream industry: including operator market and terminal equipment market. This is a segment that should be greatly developed in the future. Specifically, a combination of 5G and artificial intelligence, big data, cloud computing can give rise to more application scenarios, such as unmanned driving, smart cities, Internet of Things (IoT), and smart medical treatment, and hence will facilitate people’s daily life.

Major 5G-related materials and markets

   Key material for filter: microwave ceramic dielectric

   Compared with other materials, microwave ceramic dielectric is more advantageous in making filters. The properties, such as good frequency selection, good stability, and small size, make the material one of the first choices for 5G market in the future. The main performance of ceramic dielectric-based filters is determined by the ceramic powder formulation and production process.

   Key materials for PCB: high frequency substrate

   High frequency substrate is the most basic material for high-frequency communication. At present, the commercialized high frequency substrates include PTFE/ceramic fillers, hydrocarbon thermal/ceramic materials, thermal engineering plastics/ceramic fillers, and LCP.

   The market shares of high frequency substrates are mostly occupied by a few manufacturers such as Rogers, Taconic, Nelco, Isola, Polyflon. The total availability in the market is relatively limited.

   Antenna materials: LCP and MPI

   Industrialized liquid crystal polymer (LCP) is a new type of thermoplastic organic material, which is featured with low transmission loss (smaller than traditional substrates by ten times), and strong performance in terms of bendability, dimensional stability, and hygroscopicity.

   The US, Japanese, and Taiwanese manufacturers are dominating the global LCP market. In 2018, the global LCP capacity was approximately 70 000 tons. In China, Shengyi Technology and Luxshare Precision Industry Co., Ltd. are two major manufacturers.

   MPI is a modified material of traditional PI. Compared with LCP, MPI is lower in prices, but similar in properties.

   Plastic antenna oscillator: 3D plastic oscillator

   The plastic vibrator is one of the key components of an antenna. Compared with the traditional metal vibrator, it features small weight, low cost and handy installation. It is still in the feasibility study stage and has not yet been put into mass production. 

   The third-generation semiconductor

   The third-generation semiconductor materials SiC and GaN are resistant to high voltage and high temperature, and are applicable to a high frequency environment.

   The third-generation semiconductor materials, represented by silicon carbide, are featured with wide band gaps, high breakdown electric fields, high thermal conductivity, high electron saturation rates, and higher radiation resistance. They exhibit great application potential in fields such as optoelectronic devices, power electronics, radio frequency microwave devices, as well as lasers and detectors. Its suppliers are mostly from the US, Europe, and Japan, so the development and production of silicon carbide devices in China largely depend on imports.

   In recent years, the 48th Research Institute of China Electronics Technology Group Corporation has developed critical equipment applicable to the manufacturing of 4-6- inch silicon carbide materials and devices, including high-temperature and high-energy ion implanters, single crystal growth furnaces, and epitaxial growth furnaces, and has initially put them into practical use. The main third-generation semiconductor wafer production lines in China are shown in Table 1.

   Table 1  Key third-generation semiconductor wafer production lines in China

   Metal middle-frame of mobile phones

   In the 5G era, smartphones are becoming larger in screen and thinner in streamline. While ordinary aluminum alloys cannot meet these performance requirements because of their low strength, series 7 aluminum alloys and stainless steels will be important solutions in the future. The main manufacturers of mobile phone middle frames are shown in Table 2.

   Table 2   Main manufacturers of mobile phone middle-frame

   3D glass

   3D glass, as a cover material for mobile phones, is light, thin, transparent, clean, and is featured with anti-fingerprint. At present, mainstream brands adopt 3D glass in the production of front and rear covers for most of their high-end models. The industry is anticipated to see rapid development in the next three to five years, during which, the domestic listed companies will expand their capacities in order to occupy more market shares.

   Table 3   Major producers of 3D glass  (KKpcs)

   Ceramic cover

   Ceramic, as a mobile phone cover material, has a good texture and is featured with good abrasion resistance and good heat dissipation that can meet the requirements of communication and wireless charging technologies for the phone models.

   At present, the manufacturers of high-end nano-scale composite powders are mostly concentrated in Japan and Europe, whereas ceramic processing is relatively matured in China, led by producers such as Chaozhou Three-Circle (Group) Co., Ltd. (CTCC), LENS Technology, Sunlord Electronics Co., Ltd. and Everwin Precision.

   Electromagnetic shielding materials for mobile phones

   In the 5G era, the shortened space between internal chips in a smartphone has caused an increasing level of electromagnetic interference between the internal devices. In the context, electromagnetic shielding materials, mainly consisting of conductive plastic devices, conductive silica gel, metal products, and absorbing devices, will be badly needed in the future. 

   Heat conduction and heat dissipation materials for mobile phones

   The heat conduction materials widely used in electronic devices include heat conduction silicone wafer, heat conduction silicone grease, and heat conduction phase change materials. General materials are becoming difficult to meet the growing heat dissipation needs of current high-tech equipment, as the running speed of chips is getting faster and faster. Graphene, with heat conductivity of 5 300W/mK, boasts the best performance in heat conduction among all known materials.

   PC/PMMA composites

   In the 5G era, the application of non-metal back covers on smart products is becoming a trend. 3D glass and ceramics are mostly used as back covers on high-end models, while plastics are penetrating into low- and mid-end models because the materials are easy for processing and are low in costs.

   PC/PMMA has excellent scratch resistance, extremely high transparency and colorability, and excellent heat resistance, making it one of the best choices for making back covers of low-end models in the future. Most of the manufacturers are foreign companies, including Teijin, Kuraray, Sumitomo chemical, and Covestro, and there are a few leading producers in China, such as Longhua Film and Guangdong Dowstone Technology.

Key problems in the development of 5G communication materials in China

   Core technologies yet to make breakthroughs

   More efforts should be taken on key technologies for core upstream materials. The upstream materials for components are of low quality and poor stability; there are scarce raw materials available in China. For example, the raw materials supplied to domestic optical fiber preform plants are highly dependent on importing. Specifically, 80% of high-purity deposition and fully synthetic quartz sleeves are imported, which results in high production costs of domestic optical preforms.

   Insufficient capacity of some products 

   As for key materials for components, although compound semiconductor materials have been put into mass production in China, the total capacity is small. The output of GaAs, GaN and SiC is less than 50 000 wafers/month. At present, the demand for 8-inch and 12-inch wafers is about 5 million wafers/month.

   In terms of electronic packaging materials, only low-end polyimide films and polyimide fibers have been put into mass production, while the production of high-end materials remains scarce.

   Disconnected upstream and downstream 

   Many domestic raw materials have no information of specifications (i.e. processing standards and production parameters) available when they are supplied to users, so users may burden risks in production. 

Integrating advantageous resources to promote the development of 5G materials

   Upstream enterprises should join hands with downstream ones to make breakthroughs in technologies in information material, so as to reduce the dependence on imported high-end raw materials. For example, they should develop large-size Si wafers, high-performance GaAs, GaN and SiC, as well as upstream materials applied in electronic packaging technologies.