Effect of misalignment on the electrical characteristics of anisotropic conductive adhesive joints

The effect of misalignment on the electrical properties of anisotropic conductive film (ACF) joints is investigated in this work. It is found that along with the increase of misalignment, the connection resistance of ACF joints increases. When the misalignment in the x-direction is less than 5 μm, the increase rate of connection resistance is quite large. Then, along with the severity of misalignment, the increase rate becomes smaller. Finally, when the misalignment is close to 20 μm, the increase rate rises again. The Holm´s electric contact theory is used for understanding the connection resistance variation. On the other hand, with the increase of misalignment in the x-direction, the insulation resistance between ACF joints decreases. If the misalignment exceeded 10 μm, the decrease is prominent for the Ni particle ACF joints. This phenomenon can be explained by the effect of dielectric damage of the epoxy. The mathematical models are developed to calculate the variation of the probability of open and shorting after misalignment and predicate the maximum misalignment tolerance.