Estimation of ACF packaging failure probability for IC/substrate assemblies with different pad array dimensions

Abstract

An analytical model based on the V-shaped curve method is proposed for estimating the failure probability of anisotropic conductive film (ACF) packages with different pad array dimensions. In analyzing the failure probability of the ACF package, the probability of an opening event in the conductivity direction is modeled as a Poisson distribution, while the probability of a bridging event in the insulation direction is modeled using the enhanced box model. The overall failure probability of the package is then calculated in accordance with the inclusion–exclusion principle of combinatorial mathematics. The results presented in this study suggest that the failure probability of ACF packages with a high pad array dimension can be improved by reducing the pad height, decreasing the conductive particle size, increasing the pad pitch, increasing the pad size, or setting the ACF volume fraction close to the tip of the V-shaped curve.