According to the forecast of IEA, the proportion of renewable energy in global energy consumption will reach 30% by 2020. Among them, photovoltaic power generation is considered to be the most important in the 21st century because of its advantages of pollution-free, safety, longevity, simple maintenance, inexhaustible resources and wide distribution. The new energy has an immeasurable development potential. In 2009, polycrystalline silicon accounted for about 25% of global production capacity, silicon wafers accounted for 65%, solar cells accounted for 51%, and components accounted for 61%. According to statistics, in 2009, China accounted for 4 seats in the world’s top 10 solar energy enterprises. At the same time, there are more than 580 enterprises engaged in solar photovoltaic industry in China. In the solar photovoltaic industry, silicon-based materials are one of the best photovoltaic conversion materials and the main body of the current market. Silicon-based (polycrystalline silicon, monocrystalline silicon) solar cells account for more than 80%. The rapid development of photovoltaic industry has directly led to the rapid development of key supporting thermal field materials. The thermal field materials in photovoltaic industry mainly include high purity carbon graphite materials and C/C composites to produce high purity and large size single crystal silicon rods. At present, graphite products are widely used in the manufacturing process of silicon materials. Among them, graphite products are especially typical in Czochralski silicon process. According to incomplete statistics, there are more than 2000 units of single product in our country. Among them, the single crystal materials used in Czochralski furnace to produce silicon semiconductor devices are mainly 16 inch thermal field, while the single crystal materials used in Czochralski furnace to produce solar cells are mainly 18 inch thermal field. In addition to thermal insulation felt, the thermal field components of single crystal furnace are mainly composed of high purity specialty graphite, with more than 20 parts. With the increase of the size of single crystal, the requirements for the specification and characteristics of graphite are also higher and higher. With the progress of semiconductor technology, the diameter of silicon wafer has experienced the development process from 2 inches in 1970s to 12 inches in this century, even 16 inches. The size of the thermal field is 3 times the size of the silicon bar. That is to say, the production of 12 inch silicon single product requires 36 inch (900mm) diameter thermal field components. As mentioned above, the requirement of modern industry for material specification of thermal monocrystalline furnaces is developing towards a large scale. At present, the equipments of isostatic pressing graphite production owned by domestic graphite rods manufacturers can not meet the demand of the market. Large graphite basically depends on imports. The total amount of imported large-scale isostatic graphite should be more than 1000 tons per year. The imported graphite is expensive and the supply is not timely. This will affect the development of China’s microelectronics industry.
