Deterioration mechanism of flip chip attachment using an anisotropic conductive film and design technology for high reliability

The flip-chip technique, in which a bare chip is directly connected to a substrate, has become a key technology in producing compact electronic products, including cellular phones. In particular, the technique of using Au bumps to connect the bare chip with the substrate, with the aid of an anisotropic conductive film (ACF), is one of the most useful technologies. The most serious problem with ACF bonding technology today is that the deterioration mechanism of interconnections is not clear. This study is motivated to clarify the mechanism of deterioration and to establish the method of obtaining reliability in the design of interconnections for which ACF is used.