Composition, microstructure, and reliability of anisotropic conductive film(ACF) for flip chip on organic substrate application

Abstract

Flip chip technology using anisotropic conductive films (ACFs) is of growing interest of its some benefits such as green, simple, and cost effective process. And it is well known that the performance of flip chip assembly using ACFs is closely related with epoxy matrix properties and process conditions of chip connection. To improve thermo-mechanical properties of anisotropic conductive films (ACFs) and reliability of flip chip on organic substrate using ACFs, composition of ACFs and processing temperature of flip chip connection were studied. Related to ACF composition, the effects of epoxy monomer functionality, content of thermoplastic resin, and addition of inorganic ($SiO_2) fillers on the composite properties of cured ACFs and reliability of ACF flip chip assembly were considered. And in other aspect, the effect of processing temperature of flip chip assembly on the ACF composite properties and reliability of ACF flip chip assembly was also investigated. In chapter 1 and 2, introduction and literature survey for this study were described respectively. In chapter 3, the changes of physical and thermo-mechanical properties of ACFs, which were prepared by using di-, tri-, and tetra-functional epoxy monomers, were investigated. And the reliability of flip chip on organic board using thereof also studied. As the functionalities of epoxy monomers increased, the thermal decomposition temperature and elastic modulus of ACFs increased. Furthermore, the glass transition temperature (Tg), which was important to the high temperature stability, was also increased as the functionalities of epoxy monomers increased. But the coefficient of thermal expansion (CTE) decreased at the same time. The reason of these improvements of ACFs composite properties was originated from the increase of cure density of cured ACFs, which was proved by the measurement of density and rubber elasticity theory. Finally, the thermal cycling reliability was improved significantly as the functio...