Analysis of influential factors in determining adhesive strength of ACF joints

Abstract

This paper investigates the test speed dependency of peel strength of model ACF joints in order to clarify the influential factors in determining adhesive strength of ACF joints. Three types of flexible substrates including polyimide, polyimide covered with Cu foil and polyimide with an interdigitated Cu circuit were bonded to a glass substrate using a typical ACF with an epoxy-based binder for fabricating the model joints. The interdigitated Cu electrode pattern on the flexible substrates is able to contribute to the improvement in the peel strength of the joints by acting as an anchoring pattern. The strong interfacial adhesion that is achieved with appropriate bonding conditions can enhance the effect of the anchoring pattern. The effect of the electrode pattern also plays an important role in suppressing the decrease in the peel strength during the exposure to severe environments such as 85°C /85%RH and 85°C.