Lcd Cof Flexible Printed Circuit Board Production Process And Pcb Failure Analysis

Chip on Flex (Chip on Film, COF), a new generation package technology has been developed vigorously, in the drive of electronics miniaturizing and development of Liquid Crystal Display (LCD), which becomes one of the main package of the drive integrated circuit of LCD, PDP, etc. Flex printed circuit for COF, as one of the most important component, is in the state of rapid developing technology and great market potential. Currently, there is no domestic COF-producing factory. The COF FPC production technology at home is in the primary stage of development. So it is the hot spot of research that produce COF FPC with right fine lines adapted to the increasing IC density of integration and deceasing I/O spacing. This paper has done the beforehand research of the crucial technology of the production of COF FPC, and got the following positive results:In respect of substrate dimension stability, two substrates are verified to meet the need of COF technology though the measurement of substrates'dimension stability after vacuum lamination. There are TAIHONG 2LPSE0503MW-250 single unadhesive ED flexible copper coated lamination (FCCL) and Nippon Steel CIPW-25080 single ED FCCL.Regards to photoresists, Dupont FX915 dry film would be the best choice for the production of COF FPC after the comparison in photosensitive property, resolution, adhesiveness and operating procedure between the different resist thicknesses of Dupont FX900 series. The exposure parameters of the dry film are also optimized to fit the production of fine lines. The optimized parameters are exposure step 5 (21 step), exposure energy 150mJ/cm2 for Panel to Panel and 110mJ/cm~2 for Roll to Roll.In the aspect of fine lines producing, the effects of copper thickness, exposure energy, etching line speed of two kinds of processes to produce fine lines have been studied. Two substrates mentioned above are suited to the production of fine lines, while the property of Nippon Steel CIPW-25080 FCCL is superior to TAIHONG 2LPSE0503MW-250 FCCL. The best parameters of producing COF FPC for Panel to Panel process are exposure energy 150mJ/cm~2, exposure step 5 (21 step), etching speed 2.5m/min, while the best parameters for Roll to Roll process are exposure energy 110mJ/cm~2, exposure step 5 (21 step), etching speed 4.0m/min. By comparison between Panel to Panel and Roll to Roll mass process, Roll to Roll is outstanding of higher yield for the advantages of automation, less manual operation and management and little influence to the temperature, humidity and lustration.This paper has done mass pre-research for key technology of producing COF FPC for LCD. COF FPCs with width/spacing of 30μm/30μm are produced successfully in trial, which proves that it is feasible to produce COF FPC and brings about a bright future.Furthermore, this paper presents the failure analysis of the failure cases in the PCB application. The analysis methods and processes of the failure of BGA (Ball Grid Array), CAF (Conductive Anodic Filamentation) and chip capacitor have been studied. The contribution of failure analysis to production and quality control of PCB and electronic devices and components was also displayed.