(Printedcircuitboard, referred to as PCB) is a substrate for assembling electronic parts, is a printed board that forms point-to-point connections and printed components on a general substrate according to a predetermined design. The main function of the product is to make a variety of electronic components form a predetermined circuit connection, play the role of relay transmission, is the key electronic interconnection of electronic products. The manufacturing quality of printed circuit boards not only directly affects the reliability of electronic products, but also affects the overall competitiveness of system products, so printed circuit boards are known as "the mother of electronic system products." The development level of the printed circuit board industry can reflect the development speed and technical level of the electronics industry in a country or region to a certain extent.

　　Glass fiber yarn: glass fiber yarn is calcined into liquid state by silica sand and other raw materials in kiln, pulled into very fine glass fiber through a very fine alloy nozzle, and then twisted hundreds of glass fiber into glass fiber yarn. Kiln construction investment is huge, for the capital intensive industry, 30,000 tons of kiln needs 400 million yuan, the new kiln needs 18 months, the business cycle is difficult to master, and once the ignition must be 24 hours uninterrupted production, and after five years or so, must stop production for half a year maintenance, enter the exit cost is huge.

　　Glass fiber cloth: Glass fiber cloth is one of the raw materials of copper clad plate, made of glass fiber yarn, accounting for about 40% of the cost of copper clad plate (thick plate) and 25%(sheet). Glass fiber cloth manufacturing and weaving enterprises are similar, you can control the speed to control the production capacity and quality, and the specifications are relatively single and stable, since the Second World War almost no big changes in specifications. Unlike CCL, the price of glass fiber cloth is most affected by supply and demand, and the price has fluctuated between $0.50 and $1.00 / meter in recent years. Taiwan and China now account for about 70 per cent of global production capacity. The upstream and downstream relationship is the key to the operation, the price of a loom is 100,000 to 150,000, generally more than 100 units can be normally produced, but the subsequent heat treatment and chemical treatment equipment capital requirements are higher, up to 10 million levels, the production capacity of weaving is easy to expand, more flexible.

　　Copper foil: Copper foil is the raw material accounting for the largest proportion of the cost of copper clad plate, accounting for about 30%(thick plate) and 50%(sheet) of the cost of copper clad plate, so the price increase of copper foil is the main driving force of the price increase of copper clad plate. Copper foil is widely used, not only in the copper clad plate industry, when the copper clad plate industry is depressed, copper foil manufacturers can switch to other uses of copper foil. The price of copper foil is closely reflected in the price of copper, with the rising price of copper, copper foil manufacturers transfer the cost pressure to the downstream. The high technical barriers of the copper foil industry lead to a lack of domestic supply, high-grade copper foil still needs a large number of imports, and the cost of investment is also very large.