Investigation On Wet Etching Process Of Copper Layer Of Flexible Printed Circuit Board With 18 Micron Line Center Distance

In recent years,China has gradually become the main producing district of flexible printed circuit board(FPCB),and the proportion of FPCB output value in the world has been increasing.Benefiting from the continuous transfer of the global FPCB industry to China,domestic local enterprises represented by Jiang Su Leader-Tech Semiconductor Co.,Ltd.are expected to accelerate the rise and become world-class.Jiang Su Leader-Tech Semiconductor Co.,Ltd.is committed to the research of FPCB manufacturing and packaging,and is currently the exclusive Roll To Roll(R2R)processing company in China,which greatly improves production efficiency,but it is still in the research and development stage in intelligent manufacturing.This processing method of Jiang Su Leader-Tech Semiconductor Co.,Ltd.can greatly improve the line density and production efficiency,which achieves the line forming of the minimum 20 μm line spacing level and meets the packaging requirements of traditional driver integrated circuits(ICs).However,with the rapid development of display panels towards high refresh rate and resolution,the wiring density and wiring method of chip on film(COF)are becoming more and more difficult to meet the needs of the terminal market.Firstly,the computational fluid dynamics theory of wet etching process is introduced.In the FPCB etching process,the influence of etchant pressure distribution on the dimensional accuracy was analyzed.The etchant spraying uniformity was studied based on the turbulence model of shear stress transmission.The velocity and pressure distribution of the etchant in the spraying area was studied based on a threedimensional full model of the multi-nozzle array.And the FPCB sample was prepared according to the process parameters used in the simulation.In the experiment,the pressure sensor was applied to monitor the etchant pressure on the FPCB surface,and the cross-sectional morphology of the FPCB line was observed to verify the accuracy of the numerical simulation method.And according to the simulation and experimental results,a design of multi-nozzle array was proposed,and an 18 μm line center distance FPCB was successfully prepared.Then,the influence of FPCB etching process parameters on cavity profile was analyzed,and the etching process was simulated based on the numerical method of Euler multiphase flow model,and the influence of spraying pressure and etching time on FPCB was studied.According to the process parameters in the simulation,the FPCB sample with 18 μm line center distance was fabricated,and the actual line morphology was compared with the etching cavity profile predicted by the simulation to verify the effectiveness of the numerical simulation method.The work is the application exploration of computational fluid dynamics in the field of FPCB etching process,which lays a theoretical and technical foundation for the next preparation of high-precision FPCB packaging substrates.And it will effectively promote the industrialized mass production of high-precision FPCB packaging substrates.