Electrical conduction of anisotropic conductive adhesives: effect of size distribution of conducting filler particles

Abstract

The force–resistance relationship is investigated by considering for the first time the effect of size distribution of metallic filler particles in anisotropic conductive adhesives. It is shown, for both the elastic and plastic interactions between the metallic particle and the conducting plate, that the relationships between the applied force ( F) and the resistance can be described as power–laws (i.e. ∝ F − n ). The universal power–law relationships are found to be independent of both the mean particle size and the standard deviation of the particle size distribution. However, the exponent constant n is much larger for a non-monosized filler particle distribution than that for a monosized one. Although the power–law relationships are independent of the standard deviation of the particle size distribution and the mean particle size, a large standard deviation of particle size distribution leads to a large resistance. The theoretical prediction of the power–law relationship is found to be supported by available experimental observations.