TFT technology is developed in the the 1990s, the use of new materials and processes of large-scale semiconductor full integrated circuit manufacturing technology, liquid crystal (LC), inorganic and organic thin film electroluminescent (El and Oel) flat panel display. TFT is on the glass or plastic substrate, such as non-monocrystalline tablets (of course, can also be on the wafer) through sputtering, chemical deposition process to form the necessary for manufacturing circuit of the various films, through the processing of the membrane to make large-scale semiconductor integrated circuits (Lsic). The use of non-single crystal substrate can greatly reduce the cost, is the traditional large-scale integrated circuit to large area, multi-functional, low-cost direction of the extension. In large areas of glass or plastic substrate manufacturing control pixel (LC or OLED) switch performance of TFT than on silicon wafer manufacturing large-scale IC technology more difficult. Requirements for the production environment (100 degrees of purification), the purity of raw materials requirements (electronic special gas purity of 99.999985%), the production equipment and production technology requirements are more than semiconductor large-scale integration, is a modern production of the top technology.
Its main features are: (1) Large area: The first generation of large-area glass substrate (300mmx400mm) TFT-LCD production line in the early 90, to the first half of 2000 glass substrate area has been expanded to 680mmx880mm), and 950mmx1200mm glass substrate will also be put into operation.
In principle there is no area limit. (2) High integration: For LCD projection of the 1.3-inch TFT chip resolution of XGA contains millions of pixels.
With a resolution of SXGA (1280x1024) 16.1-inch TFT array amorphous silicon film thickness is only 50nm, and the tab on glass and system on glass technology, its IC integration, the equipment and supply technology requirements, technical difficulties are beyond the traditional LSI. (3) Powerful: TFT as the first matrix location circuit to improve the light valve characteristics of the liquid crystal. For high-resolution display, the precise control of object element is achieved by 0-6v range voltage regulation (typical value 0.2 to 4V), which makes it possible for LCD to achieve high quality high-resolution display. TFT-LCD is the first flat panel display in human history that exceeds the CRT in quality.
And people began to integrate the drive IC to the glass substrate, the entire TFT function will be more powerful, this is the traditional large-scale semiconductor integrated circuit can not match.
(4) Low cost: glass substrates and plastic substrates fundamentally solve the cost of large-scale semiconductor integrated circuits, and open up wide application space for the application of large-scale semiconductor integrated circuits. (5) Flexible process: In addition to the use of sputtering, CVD (chemical vapor deposition) MCVD (molecular chemical vapor deposition), such as the traditional process of film, laser annealing technology has also begun to apply, not only can make amorphous film, polycrystalline film, can also make single crystal film.
Not only can the silicon film be made, but also other Ⅱ-ⅵ and Ⅲ-ⅴ semiconductor films can be made.
(6) A wide range of applications, TFT technology based liquid crystal Flat panel display is the backbone of the information society, but also the technology can be applied to the rapid growth of the thin film transistor organic light-emitting (tft-oled) flat panel display also in the rapid growth.