Low-Temperature fine-pitch flip-chip bonding by using snap cure adhesives and Au stud bumps

Fine-pitch flip-chip bonding with a low-temperature budget can be considered not only as the key enabler of hybrid and flexible electronics, but also as a requirement for 3D packaging platforms with temperaturesensitive components. In this study, low-temperature flip chip bonding by using snap cure non-conductive paste (NCP) and anisotropic conductive paste (ACP) was investigated. By exploiting the compliancy of soft gold-studbumps and compressive stress induced by snap cure adhesives, flip-chip bonding with both adhesives were successfully conducted in a thermode station at 170°C within a few seconds. It was also found out, that for finepitch flip-chip bonding with Au-stud bumps, snap cure NCA is the better choice, since it can handle finer pitches, provide sufficient underfilling, has lower cost and simplified process.