A study on the thermal deformation of ACF assemblies using moire interferometry and FEM

The use of flip-chip technology has many advantages over other approaches for high-density electronic packaging. ACF (anisotropic conductive film) is a major flip-chip technology, which has short chip-to-chip interconnection length, high productivity, and package miniaturization. Therefore, many researchers and manufacturers are interested in the ACF connection scheme. In this paper, the thermal deformations of ACF flip-chip assemblies are studied using moire interferometry and finite element analysis. First, the effects of filler content on the mechanical properties of ACF are studied theoretically and experimentally. In the theoretical study, material properties are calculated by analytical methods for composite materials such as the Mori-Tanaka method and the Shapery model. Effective material properties are utilized for finite element analysis. Second, thermal deformations of ACF assemblies are measured via moire interferometry. Isothermal loading, where ΔT=-75°C, is applied to ACF assemblies. Finally, numerical verification between moire measurement and theoretical prediction is performed with finite element analysis