The manufacturing process of the manufacturing process of TFT-LCD TFT-LCD has the following parts: forming a TFT array on the TFT substrate; forming a color filter pattern on a color filter substrate and a ITO conductive layer; forming a liquid crystal box with two substrates; assembling the module assembly of the peripheral circuit and the assembly of the backlight.
1. the process of forming TFT arrays on the TFT substrate has now realized the industrialization of TFT types including: amorphous silicon TFT (a-Si TFT), polysilicon TFT (p-Si TFT), and monocrystalline silicon TFT (c-Si TFT). A-Si TFT is still the most used at the moment. The manufacturing process of a-Si TFT is first sputtering the gate material film on the borosilicate glass substrate, and then forming the grid wiring pattern after mask exposure, development and dry etching. A stepper exposure machine is used in general mask exposure. The second step is to use PECVD method to form continuous film forming SiNx film, undoped a-Si film and phosphorus doped n+a-Si film. Then mask exposure and dry etching are used to form the a-Si pattern of the TFT part. The third step is to form transparent electrode (ITO film) by sputtering film forming method, and then form the display electrode pattern through mask exposure and wet etching. The fourth step is the use of mask exposure and dry etching. The fifth step is to make AL and other sputtering films, and then use the mask exposure and etching to form the source, drain and signal line patterns of TFT. Finally, the protective insulating film is formed by the PECVD method, and the etch of the insulating film is made by the mask exposure and dry etching, which is used to protect the gate and the end of the signal wire electrode and the display electrode. At this point, the whole process is completed. TFT array technology is the key of TFT-LCD manufacturing process, and it is also the most investment part of equipment. The whole process needs to be carried out under very high purification conditions (such as level 10).
2. the coloring parts of color filter formed on the color filter (CF) substrate are dyestuff, pigment dispersion, printing, electrodeposition and inkjet. At present, the pigment dispersion method is the main method. The first step of the pigment dispersing method is to disperse the uniform fine particles (the average particle size is less than 0.1 micron m) (R, G and B trichromatic) in the transparent photosensitive resin. Then, they are sequentially formed by R., G. and B tricolor patterns by coating, exposing and developing. Photolithography technology is used in manufacturing, and the devices used are mainly coating, exposure and developing devices. In order to prevent light leakage, usually with a black matrix at the junction of three RGB (BM)
In the past, multi layer sputtering was used to form single layer metal chromium film. Now there are also BM BM or Cr resin composite carbon resin. In addition, it is necessary to make a protective film on BM and to form a IT0 electrode, because the substrate with color filter is the liquid crystal box which is used as the front base plate of the LCD screen and the rear substrate with TFT. So we must focus on the location problem, so that each element of the color filter corresponds to every pixel of the TFT substrate.
The preparation process of the 3. liquid crystal box is first to apply polyimide film on the surface of the upper and lower substrates and through the friction process to form the orientation films which can be arranged by the inducible molecules according to the requirements. After that, the sealant material was laid around the TFT array substrate, and the gasket was sprayed on the substrate. At the same time, silver paste was coated on the transparent electrode end of CF substrate. Then the two substrates are bonded to each other, so that the CF pattern and TFT pixel pattern are aligned one by one, and then the sealing material is solidified by heat treatment. When printing the sealing material, we need to leave the injection port to vacuum the liquid crystal. In recent years, with the progress of technology and the increase of the size of the substrate, the process of making the box has also been greatly improved. It is more representative of the change of the mode of the filling crystal. From the original box to the box, the perfusion is changed to the ODF method, that is, the perfusion crystal is synchronized with the box. Besides, the way of gasket is no longer using traditional spraying method, but is directly made on the array by photolithography.
4. peripheral circuit, assembly backlight module assembly process, after the liquid crystal box manufacturing process is completed, on the panel needs to install the peripheral drive circuit, and then on the two substrate surface pasted on the polarizer. In the case of transmission LCD., the backlight is also installed.