TFT technology was developed in the 1990s. Large-scale semiconductor all-integrated circuit manufacturing technologies using new materials and new processes are used in liquid crystal (LC), inorganic and organic thin film electroluminescent (EL and OEL) flat panel displays. basis. The TFT is formed on a non-single wafer such as a glass or plastic substrate (on the wafer, of course) by sputtering, chemical deposition processes, and various films necessary for the production of a circuit, and a large-scale semiconductor integrated circuit (LSIC) manufactured by processing the film. . The use of non-single-crystal substrates can significantly reduce costs, which is an extension of traditional large-scale integrated circuits to a large area, multi-function, and low-cost direction. Fabricating TFTs that control pixel (LC or OLED) switching performance on large area glass or plastic substrates is more difficult than making large scale ICs on silicon wafers. The requirements for the production environment (purity is 100), the purity of the raw materials (the purity of the electronic special gas is 99.999985%), the requirements for production equipment and production technology exceed the large-scale integration of semiconductors, and it is the top of modern production. technology. Its main features are:
(1) The use of good characteristics: low voltage applications, low drive voltage, solid-state use of improved safety and reliability; flat, thin, saving a lot of raw materials and use of space; low power consumption, its power consumption is about CRT monitors One-tenth of that, reflective TFT-LCDs are only about one-hundredth that of CRT, which saves a lot of energy; TFT-LCD products also have specifications, size series, variety of types, easy and flexible to use, repair and update. , easy to upgrade, long life and many other features. The display range covers the application range of all displays from 1 inch to 40 inches and the large projection plane, is a full-size display terminal; display quality from the simplest monochrome character graphics to high resolution, high color fidelity, High-brightness, high-contrast, high-response speed video display of various specifications; direct-view, projection, perspective, and reflective.
(2) Manufacturing technology has a high degree of automation, and large-scale industrial production features are good. TFT-LCD industry technology is mature, the production rate of large-scale production reaches more than 90%.
(3) TFT-LCD is easy to integrate and update, and it is a perfect combination of large-scale semiconductor integrated circuit technology and light source technology, and has great potential for further development. Currently, there are amorphous, polycrystalline, and monocrystalline TFT-LCDs. In the future, there will be TFTs of other materials, both glass substrates and plastic substrates.
(4) Good environmental protection characteristics: no radiation, no flicker, no harm to the user's health. In particular, the advent of TFT-LCD e-books will bring humans into the era of paperless office and paperless printing, which will lead to a revolution in the way humans learn, disseminate and record their civilization.
(5) Wide application range, normal temperature range from -20°C to +50°C can be used. After the temperature-reinforced TFT-LCD, the low temperature operating temperature can reach minus 80°C. Can be used as a mobile terminal display, desktop terminal display, but also for large-screen projection TV, is a full-size high-performance video display terminal.
(6) Low cost: Glass substrates and plastic substrates fundamentally solve the problem of the cost of large-scale semiconductor integrated circuits, and open up a vast application space for the application of large-scale semiconductor integrated circuits.