Research On Process Optimization Of Dry Etching Process Using TFT Multi-mode Glass Technology

With the rapid development of the TFT-LCD industry,many new technologies and processes have been applied in it.In order to meet the market demand for different sizes panels and to prevent the waste of actual production capacity because of the simplification of dimensional production,the Multi-Mode Glass?MMG?technology is applied.MMG technology can mix and match different size panels on the same substrate according to the product specification requirements,which can avoid product singulation and improve the utilization rate of glass substrates,thereby reducing production costs and improving market competitiveness.Now MMG technology is widely used in actual production,but there are still some problems,such as the poor a-Si Remain uniformity after dry etching,resulting in abnormal electrical performance of products,affecting product quality and yield.The study found that the reason of this problem is the significant load effect of the MMG mixed-cut product because of the large difference of its two-size pixels per inch?PPI?and metal density.In order to improve this problem,optimization is generally performed from both the dry etching process surface and the design surface.In this paper,the a-Si Remain uniformity defects occurred in the actual production of the MMG technology was studied and analyzed.The a-Si Remain uniformity of the product was optimized through the adjustment of the dry etching process parameters,whose optimal value is ultimately determined by the influence degree of the process parameters,such as temperature,gas flow rate,power,and pressure on the etching rate and so on,on the a-Si Remain uniformity in the design of experiment?DOE?.Among them,the etching gas will shrink at high pressure as its pressure increases,which makes etching rate in the middle of the substrate fast,while the Plasma expands as the pressure is reduced,which makes Etching rate around the base plate greater than etching rate in the middle of the substrate;the more the number of plasma per unit volume are more and the larger the power supply power is,the greater the number of units in the Plasma are,and the faster the etching rate is;the higher the proportion of the main etching gas is,the greater the density of the active groups is and the faster the etching rate is;and the etching gas distribution mainly affects the uniformity of the main plate,so that the local etching rate is accelerated or slowed,which is a match witn the pre-CVD process film-forming conditions.In this paper,the samples are analyzed by scanning electron microscope,electrical tester and thickness measurement instrument.The results show that the optimum conditions for the production of pure cut products?55 inches?are as follows,Power:source/bias is 3000/4000V,pressure is 30 mT,FRC is 5%,MMG mixed-cut products?43&22?dry etching process optimal conditions pressure is 30 mT,source is 3000V,bias is 6000V,Cl₂ and SF₆ ratio is 10 to 1.At the same time,it is found that widening process margin can be prevented through the refinement of the design specifications of MMG mixed products,such as sizing value,dummy pixel,Photo Spacer?PS?density,a-com Separate design,and so on.