Feasibility study of non-conductive film (NCF) for plasma display panel (PDP) application
In this study, attempts were made to develop an electrically reliable and low cost bonding process for plasma display panels (PDPs) by using non-conductive film (NCF). The adhesive joints were constructed with Ag electrodes on a glass substrate and Au finished Cu electrodes on a flexible printed circuit (FPC). To clarify the feasibility of NCF application, all experimental results of NCF were compared with those of anisotropic conductive film (ACF) which is currently used for PDP application. The reliability of adhesive interconnections using NCF and ACF was evaluated by measuring daisy resistance during high temperature and humidity storage test (85 °C, 85% RH for 1000 h). Ag electrochemical migration, which leads to the degradation of surface insulation resistance, was also investigated by measuring insulation resistance during the storage test (1000 h at 85 °C and 85% RH). The initial resistance of NCF joints was lower than that of ACF joints due to larger contact area between Ag and Au finished Cu electrodes in the NCF joints. During the reliability test, the daisy resistances of both joints increased slightly due to Z-directional swelling of the adhesives, but NCF joints showed more stable resistance than ACF joints. In addition, upon application of high voltage of 100 V (DC current), severe degradation of insulation resistance due to the Ag migration was observed in ACF joints, whereas no remarkable decrease of insulation resistance was observed in NCF joints. Conclusively, the application of NCF to PDP interconnection process has good potential from a practical point of view.