U-PCR And Line Mura Realization And Application Of Display Panel Detection

With the continuous development of the display industry and the wide application of the display panel,people have higher requirements for its display quality,panel clarity and other indicators,so in the display panel production industry,more efficient detection technology is needed.At present,LTPS(low temperature polycrystalline silicon)uses excimer as the material of the heat source.After the incident light passes through the optical shaping system,it becomes a light beam with uniform energy.The light beam irradiates to the surface of glass substrate with amorphous silicon characteristic structure.When each unit on the glass substrate receives the energy of laser beam,it,its structure will be changed to polysilicon,and the operation conditions of the operation process need to be below 600 ?,so the process is also called low temperature polysilicon process.)The polysilicon thin film transistor in has been widely introduced as a new technology,and the detection of polysilicon needs electrical and optical tests.According to the electrical characteristics,although the wave photoconductivity decay(u-pcd: Microwave photo conductivity decay,using high-energy laser to excite the semiconductor material to generate electron and hole pairs,using high-density microwave to detect the material A non-destructive measurement technique for the concentration and recombination time of mesons and oligons.)It is a universal technology for testing minority carrier lifetime in the world,but for polysilicon deposited on glass substrate,the signal is very weak,and the stability is not good,so it is difficult to realize the accurate measurement of carrier concentration,and it is also difficult to judge the electrical performance uniformity of polysilicon in large generation production lines.The u-pcr(microwave photo conductivity response,a kind of thin film detection in the field of display panel,is realized by improving the equipment.By means of UHF microwave reflection,the photoconductivity reduction of semiconductor samples excited by short wave laser is detected,so as to obtain a non-contact test method of sample carrier concentration before and after recombination.)This technology can greatly improve the stability of the test results,and help the display panel to break through the bottleneck of large generation detection.With the development of display panel towards large size,light weight and high resolution,excimer laser anneal process(ELA,exciter laser annel)is mainly used to realize the rapid preparation of polysilicon thin film transistors.However,due to the control of laser beam stretching and stability,the probability of defects(mura)[1] in the production process is greatly increased,and the mura produced by ELA is basically The lighting module can only be found in the rear section,which takes a long time and has a great impact.However,the traditional visual inspection method mainly depends on the experience and subjective feelings of the inspector to detect mura defects and evaluate their grades,which results in different inspectors' different judgment results for the same mura defect.The existing automatic optical inspection instrument(AOI,automated optical inspection,full name is automatic optical inspection,which is based on the optical principle to detect the common defects encountered in production.)It can only identify the macro dirtiness mura,but it is still helpless to the mura produced by ELA.Therefore,it is necessary to develop an accurate and fast method of mura defect detection based on machine vision,which is not interfered by external conditions.The line mura detection technology is realized through the improvement of the existing AOI equipment(that is,a technology that scans the display panel by using the high-definition CCD camera at a specific angle,uses the LED highlight light source to take pictures in real time,and processes the video signal to obtain the complete mura characteristic curve of the plane.)It realizes the accurate measurement and judgment of ELA mura,realizes the tedious process of replacing the manual visual inspection,and greatly improves the production efficiency.Faced with the expanding demand for OLED screen at home and abroad,the domestic flat panel display industry has been expanding production on a large scale,and the low yield is an important problem faced by domestic manufacturers before realizing mass production.In order to improve the yield,it is urgent to have a technology that can quickly detect the film forming quality of each process and feedback the defects of each process in real time.The microwave photoconductive decay response can be used to test the parameters of the deposited film quickly and accurately.If the linear Mura test is combined,the defects of the previous process can be feedback in real time.This will promote the steady development of domestic flat panel display industry and improve the positive output and yield.Therefore,through the re optimization of the key modules of upcd,this paper realizes and verifies the application value of u-pcr technology in the film detection of display panel,realizes the module design of Mura detection module for ELA process,which greatly improves the efficiency of Mura detection existing in Ela process.At the same time,by discussing the relationship between u-pcr and line Mura technology and the quality of polysilicon film,a new automatic polysilicon rating method which can be used in the field of display panel detection is proposed.The manual detection of Mura is abandoned,the production efficiency is improved,and the quality of polysilicon and the uniformity of electrical performance are improved.