Effect of Silane Coupling Agents on the Underfill Adhesion undergoing Heat Aging Test

Underfill (UF) is a thermosetting electronic material commonly used in flip chip packaging. Filling the gap between the silicon chip and the substrate using UF can improve the reliability of the flip chip system. However, as a polymer electronic material, the properties of UF can be significantly influenced by the high temperature in the working environment of flip chip. High temperature can lead to the degradation of adhesion between underfill and silicon chips, and thereby compromise the reliability of the flip chip. One method to improve the high temperature reliablity of UF is to add silane coupling agent in to UF. Silane coupling agent is a type of organic or inorganic compound linking material, which can enhance the silicon/underfill adhesion at high temperatures. At present, in most studies on silane coupling agents, the selected types of silane coupling agents are too single, and there is a lack of systematic research on silane coupling agents. Therefore, from the point of view of the active properties of molecular functional groups and the length of molecular chains, a batch of silane coupling agents were systematically screened and underfill was reconfigured to explore the influence of silane coupling agents on the bonding strength of underfill at high temperatures. The bonding performance of different types underfills at different temperatures was characterized by adhesive strength. The results show that the decreasing trend of underfill adhesive strength at high temperatures is related to the type of coupling agent.