Behaviour of anisotropic conductive joints under mechanical loading

Abstract

Anisotropic conductive films (ACFs) received a great deal of attention in recent years for interconnection applications in electronic packaging. This paper reports the behaviour of ACF joints under various mechanical loading, i.e., die shear and cyclic fatigue in shear. The mechanical behaviour of ACF joints that have been exposed to environmental effects, i.e., high moisture and elevated temperature (autoclave test conditions) has been examined using die shear test. The maximum shear force prior to fracture was determined as 465.0 N, at which the contact resistance is found extremely high and can be considered as open circuits. Epoxy based ACF exhibits insignificant plastic deformation, especially for samples that have undergone autoclave test. Reduction trend was observed in the shear moduli over autoclave test time for ACF joints. Fracture surface of ACF that failed in shear test shows spalling and less plastic deformation after exposed to autoclave test. For cyclic fatigue test, the endurance limit is determined at about 143.5 N and the corresponding calculated endurance ratio is around 32.0%.